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    QoE-based performance evaluation of scheduling algorithms over LTE

    Alfayly, A. ; Mkwawa, I. ; Sun, L. ; Ifeachor, E.
    Globecom Workshops (GC Wkshps), 2012 IEEE

    DOI: 10.1109/GLOCOMW.2012.6477781
    Publication Year: 2012 , Page(s): 1362 - 1366

    IEEE Conference Publications

    The LTE specification provides Quality of Service (QoS) of multimedia services with fast connectivity, high mobility, and security. However, 3GPP specifications have not defined scheduling algorithms to support real-time and non-realtime application services, this has led to the development of a variety of scheduling algorithms in the recent years. Performance is a key factor for assessing the scheduling algorithms. However, the performance analysis and evaluation for existing scheduling algorithms are limited to QoS parameters (e.g. in terms of throughput, packet loss and delay) and/or fairness metrics. It is not clear how these scheduling algorithms perform in terms of Quality of Experience (QoE) metrics (e.g. MOS score) which are more closely linked with end user experience or user perceived quality. In this paper, we investigate and evaluate the performance of three popular LTE downlink schedulers (proportional fairness (PF), exponential proportional fairness (EXP-PF), and modified largest weight delay first (M-LWDF)) in terms of QoE metric (i.e. MOS score) in addition to normal QoS metrics (e.g. packet loss and delay) for VoIP applications. Simulation results (based on LTE-Sim) show that the best suitable downlink scheduling algorithm is MLWDF, which has short end-to end delay (less than 50ms) and allowing maximum number of user access (more than 50 users) at acceptable MOS score (MOS over 3.5). The widely used scheduling algorithm (PF) will increase its end-to-end delay over 200ms, when number of user access is over 30. This will limit its application for VoIP when user access number increases. This work would help to assist the design and development of QoE-driven scheduling algorithms for mobile multimedia applications in the future. View full abstract»

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    Admission control strategies and QoS evaluation based on mobility in LTE

    Ben Rejeb, S. ; Nasser, N. ; Tabbane, S.
    Global Communications Conference (GLOBECOM), 2013 IEEE

    DOI: 10.1109/GLOCOMW.2013.6855724
    Publication Year: 2013 , Page(s): 4883 - 4888

    IEEE Conference Publications

    Mobile communication systems have evolved considerably in recent years encouraging the deployment of multiple systems or multi-cellular technology. Quality of service (QoS) offered to mobile users improves from one system to another for example 4G systems, offer better QoS than that offered by 3G and 3.5G systems. In addition, 4G systems such as LTE (Long Term Evolution) can expand cellular coverage and provide higher throughput. New technologies enhance accessibility to the Internet. Migration services from Internet to mobile networks become an important research topic for telecommunications sector. This paper calculates and evaluates system performance by developing a new LTE mechanism for allocating resources in the downlink based on call admission control (CAC) taking into account mobility within and between cellular users. This mechanism uses adaptive modulation and coding (AMC) that divided the geographical area into several concentric regions. With this mechanism each call accepted by the system maintains its initial throughput regardless of the position of the user in the cell. View full abstract»

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    Feasibility evaluations for secondary LTE usage in 2.7–2.9GHz radar bands

    Rahman, M.I. ; Karlsson, J.S.
    Personal Indoor and Mobile Radio Communications (PIMRC), 2011 IEEE 22nd International Symposium on

    DOI: 10.1109/PIMRC.2011.6140017
    Publication Year: 2011 , Page(s): 525 - 530
    Cited by:  Papers (6)

    IEEE Conference Publications

    In this paper, we have studied the potential for secondary usage of radar bands by 3GPP LTE eNB devices in different scenarios, such as HeNB transmitters located at street level, HeNB transmitters located at high-rise buildings, macro LTE transmitter, etc. Different pathloss models are used to best suite the scenarios. By using different types of radar characteristics (e.g. radio navigations radars, meteorological radars, etc) and a protection requirement of -10dB Interference-to-Noise Ratio (INR), we have shown that in some scenarios, the required distances for adjacent channel radar usage in 2.7-2.9GHz band are quite reasonable. This means, in those scenarios, it could be possible to utilize the radar bands for secondary LTE systems. A protection margin of 18 to 20dB can be added for capturing the aggregate interference effects from multiple secondary interferers for downlink direction. More detailed system level investigations are required in this direction for further understanding the secondary usage in this band. View full abstract»

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    Downlink MIMO with Frequency-Domain Packet Scheduling for 3GPP LTE

    Suk-Bok Lee ; Choudhury, S. ; Khoshnevis, A. ; Shugong Xu ; Songwu Lu
    INFOCOM 2009, IEEE

    DOI: 10.1109/INFCOM.2009.5062041
    Publication Year: 2009 , Page(s): 1269 - 1277
    Cited by:  Papers (27)

    IEEE Conference Publications

    This paper addresses the problem of frequency domain packet scheduling (FDPS) incorporating spatial division multiplexing (SDM) multiple input multiple output (MIMO) techniques on the 3GPP long term evolution (LTE) downlink. We impose the LTE MIMO constraint of selecting only one MIMO mode (spatial multiplexing or transmit diversity) per user per transmission time interval (TTI). First, we address the optimal MIMO mode selection (multiplexing or diversity) per user in each TTI in order to maximize the proportional fair (PF) criterion extended to frequency and spatial domains. We prove that the SU-MIMO (single-user MIMO) FDPS problem under the LTE requirement is NP-hard and therefore, we develop two approximation algorithms (one with full channel feedback and the other with partial channel feedback) with provable performance bounds. Based on 3GPP LTE system model simulations, the approximation algorithm with partial channel feedback is shown to have comparable performance to the one with full channel feedback, while significantly reducing the channel feedback overhead by nearly 50%. View full abstract»

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    Exponential Effective SIR metric for LTE downlink

    Olmos, J. ; Serra, A. ; Ruiz, S. ; Garcia-Lozano, M. ; Gonzalez, D.
    Personal, Indoor and Mobile Radio Communications, 2009 IEEE 20th International Symposium on

    DOI: 10.1109/PIMRC.2009.5449772
    Publication Year: 2009 , Page(s): 900 - 904
    Cited by:  Papers (6)

    IEEE Conference Publications

    3GPP LTE is the evolution of UMTS which will make possible to deliver next generation high quality multimedia services according to the users' expectations. The flexibility of the downlink OFDM radio interface with Adaptive Modulation and Coding (AMC), MIMO and H-ARQ plays a crucial role in achieving the low latency and high spectral efficiency promised by the new radio access standard. This paper presents a LTE DL link level simulator whose main purpose is to generate suitable look-up tables to interface with a system level simulator. In this context, the Exponential Effective SIR (EESIR) metric is a link abstraction model that is used to properly characterize multistate channels. The reference BLER curves in AWGN channel and the parameters of the EESIR model are given for the complete list of CQI's specified for LTE DL. The obtained results also include curves of mean link level throughput for different AMC formats and MIMO configurations. View full abstract»

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    Energy-throughput simulation approach for heterogeneous LTE scenarios

    Baddour, R. ; Chiumento, A. ; Desset, C. ; Torrea-Duran, R. ; Pollin, S. ; Van der Perre, L. ; Lauwereins, R.
    Wireless Communication Systems (ISWCS), 2011 8th International Symposium on

    DOI: 10.1109/ISWCS.2011.6125377
    Publication Year: 2011 , Page(s): 327 - 331

    IEEE Conference Publications

    In order to increase overall LTE system performance femtocells have been proposed, as a user-based solution promising to give much better service to the user specially indoor. Their deployment should improve the total system capacity noticeably and decrease drastically the power consumption. On the other hand these small indoor cells make network planning strategies much more complex given the uncertainty of their position and their load; femtocells are, after all, managed by the users. The goal of this work is to provide a simulation approach to determine the effects of heterogeneous cell deployment on the performance of an LTE network. The simulation framework allows to realistically compare the power consumption and throughput of the overall system. The key components are the combination of indoor and outdoor propagation modeling, and the diversification of femto, micro and macro-cell energy consumption models. The model further contains complex citylike building structures, multiple communication layers (eNodeBs and femtocells) distributed over a three-dimensional map and numerous users moving across different areas while adapting their service requirements. The simulation approach results in relatively computationally inexpensive simulations and allows to model the expected throughput and energy consumption for various heterogeneous LTE scenarios. View full abstract»

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    A packet age based LTE uplink packet scheduler for M2M traffic

    Afrin, N. ; Brown, J. ; Khan, J.Y.
    Signal Processing and Communication Systems (ICSPCS), 2013 7th International Conference on

    DOI: 10.1109/ICSPCS.2013.6723987
    Publication Year: 2013 , Page(s): 1 - 8

    IEEE Conference Publications

    M2M applications exhibit a wide variety of QoS requirements, but many, particularly those associated with monitoring and/or control, are delay sensitive and therefore have specific packet delay budgets. One of the issues when supporting such delay sensitive M2M applications over a wide area cellular standard such as LTE is that the base station scheduling entity cannot precisely ascertain when pending uplink packets at devices were generated. This makes scheduling according to deadlines based upon packet delay budgets very challenging and ultimately involves some degree of error. In this paper, we propose a new delay sensitive scheduler that increases the probability of satisfying the delay budget of packets by exploiting Packet Age (PA) data explicitly reported by devices. The PA is a new MAC Control Element that represents the age of the oldest pending packet in the device buffers and is sent by devices in parallel with the existing Buffer Status Report (BSR) that contains volume and priority data. The overhead associated with the PA MAC control element is extremely small (2 bytes). We demonstrate the performance of the new technique with an OPNET simulation of an LTE TDD system serving event driven delay sensitive M2M traffic, comparing the results when PA reporting is enabled versus disabled for essentially the same uplink scheduling algorithm. View full abstract»

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    Power efficient resource mapping techniques and their tradeoffs in LTE Multiple Access

    Boyapati, H.K. ; Chaudhari, S. ; Thirija Sharmila, A.
    Recent Advances and Innovations in Engineering (ICRAIE), 2014

    DOI: 10.1109/ICRAIE.2014.6909228
    Publication Year: 2014 , Page(s): 1 - 5

    IEEE Conference Publications

    Orthogonal Frequency Division Multiple Access (OFDMA) has become the key physical layer technology for all future wireless standards including LTE, because of its high spectral efficiency and its capacity to combat multipath fading. Inspite of its advantages, one of the major drawbacks of OFDMA system is its high Peak to Average Power Ratio (PAPR) value which is directly related to power consumption of the system. Although power consumption is not a problem for downlink channel, it is one of the main issues for uplink channel because the available power for the mobile user is limited. To overcome this issue, in LTE, for the uplink channel, Discrete Fourier Transform (DFT) spread OFDMA or Single Carrier-FDMA (SCFDMA) system is used. In this paper, we intend to analyze PAPR variation by varying critical parameters of LTE baseband such as number of subcarriers and different modulation and coding schemes. We also examine the power savings and their tradeoffs for resource mapping schemes such as OFDMA, Localized SCFDMA(LFDMA) and Interleaved SCFDMA (IFDMA). View full abstract»

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    Live field trial of Licensed Shared Access (LSA) concept using LTE network in 2.3 GHz band

    Palola, M. ; Matinmikko, M. ; Prokkola, J. ; Mustonen, M. ; Heikkila, M. ; Kippola, T. ; Yrjola, S. ; Hartikainen, V. ; Tudose, L. ; Kivinen, A. ; Paavola, J. ; Heiska, K.
    Dynamic Spectrum Access Networks (DYSPAN), 2014 IEEE International Symposium on

    DOI: 10.1109/DySPAN.2014.6817778
    Publication Year: 2014 , Page(s): 38 - 47

    IEEE Conference Publications

    This paper presents the results from a live field trial of the new Licensed Shared Access (LSA) concept using a TD-LTE network in the 2.3 GHz spectrum band in Finland. In the trial a live LTE network shares the spectrum from incumbent programme making and special events (PMSE) service including cordless cameras without causing harmful interference. The trial implements the new LSA concept and the required new building blocks including LSA Repository for spectrum availability information and LSA Controller for commanding the mobile communication network in the band. The trial uses a real TD-LTE base station, real network management system, and real core network. Incumbent spectrum usage data is collected to the LSA Repository and used by the LSA Controller to retrieve available spectrum bands. LSA Controller uses the network management system to configure the base station according to the spectrum availability information. Incumbent spectrum users' rights are protected by evacuating the LSA band and handing users over from the LTE network to other networks when requested by the incumbent spectrum user. Numerical results are presented to quantify the duration of the LSA band evacuation process. The demonstration shows that the new LSA concept can be implemented with existing network elements and a minimum amount of new components. The first performance results on the LSA band evacuation times indicate that the LSA band can be evacuated and released in good time and the incumbents' rights can be protected. View full abstract»

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    Priority Access for public safety on shared commercial LTE networks

    Borkar, S. ; Roberson, D. ; Zdunek, K.
    Telecom World (ITU WT), 2011 Technical Symposium at ITU

    Publication Year: 2011 , Page(s): 105 - 110

    IEEE Conference Publications

    In order to provide nationwide broadband access to public safety users especially during emergencies, it is an imperative that the public safety user has access to a shared commercial network This document provides a summary of a proposed LTE based architecture and presents the results for ensuring that the spectrum usage is maximized and public safety requirements are fully met. Simulation based results for various scenarios show the guaranteeing of the radio admission and traffic bearer assignments for the public safety users based on the LTE radio admission control mechanisms and allocation and retention priority schemes. A meaningful approach of a public user allocated space in the shared commercial network results in maximizing the frequency spectrum use as well as ensuring that the public safety priority requirements are met. View full abstract»

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    Modeling 3GPP LTE Advanced DRX Mechanism Under Multimedia Traffic

    Ke Wang ; Xi Li ; Hong Ji
    Communications Letters, IEEE

    Volume: 18 , Issue: 7
    DOI: 10.1109/LCOMM.2014.2323231
    Publication Year: 2014 , Page(s): 1238 - 1241

    IEEE Journals & Magazines

    The discontinuous reception (DRX) mechanism is adopted in the Long Term Evolution Advanced (LTE-A) system as a core technology to lower the power consumption of user equipment. With the development of Mobile Internet, there is an increasing need to optimize the DRX parameter configuration to accommodate the mobile multimedia applications that exhibit self-similarity. In this letter, we model the LTE-A DRX mechanism under self-similar traffic based on a Discrete Time Semi-Markov Process. With our model, the power saving factor and the expectation of wake-up delay can be accurately estimated for a specific DRX parameter configuration. The accuracy of the proposed model is validated through comparison with simulation results. View full abstract»

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    Self-configuration of basic LTE radio parameters using Magnetic Field Model

    Premnath, K.N. ; Pradhan, P. ; Darshan, R. ; Schmelz, L.C.
    Wireless Communication Systems (ISWCS), 2012 International Symposium on

    DOI: 10.1109/ISWCS.2012.6328325
    Publication Year: 2012 , Page(s): 36 - 40

    IEEE Conference Publications

    The success of communication service providers (CSPs) relies on efficient operational strategies for managing their networks, including the planning, optimisation and maintenance, in order to meet the desired Quality of Service (QoS), Quality of Experience (QoE) and business goals and requirements. Such business goals and requirements include, amongst others, the reduction of Operational and Capital Expenditure (OPEX and CAPEX). Self Organising Networks (SON) functionalities, including self-configuration, self-optimisation and self-healing, play a crucial role in minimising OPEX [1]. SON has been leveraged by the operator forum Next Generation Mobile Networks (NGMN) [12] and standardised by the 3rd Generation Partnership Project (3GPP) [9][11], in particular for Long Term Evolution (LTE) radio access networks. This paper presents a new solution for the self-configuration of the basic LTE radio parameters Physical Cell ID (PCI) and Physical Random Access Channel (PRACH) using Magnetic Field Model (MFM) techniques, providing a new approach with respect to the existing solutions for PCI allocation [3] in LTE networks. View full abstract»

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    A low complexity channel estimation approach of LTE downlink system

    Subin Wang ; Chunjing Hu ; Tao Peng ; Wenbo Wang
    Communication Technology (ICCT), 2012 IEEE 14th International Conference on

    DOI: 10.1109/ICCT.2012.6511204
    Publication Year: 2012 , Page(s): 143 - 147

    IEEE Conference Publications

    Channel estimation is critical to receiver performance in the long term evolution (LTE) system. Reference signals are interspersed with data signals among the subcarriers to aid channel estimation. Linear minimum mean square error (LMMSE) channel estimation is an efficient approach to estimate the knowledge of channel with high complexity. This paper proposed a channel estimation approach based on singular value decomposition (SVD) for downlink channel in LTE system. Compared to the conventional algorithm, the proposed approach investigates the channel autocorrelation matrix respectively and substitutes it by small submatrices to reduce the complexity. The simulation result demonstrates that the complexity is significantly reduced with negligible performance degradation, so it could be a candidate of the channel estimation algorithm for downlink channel estimation in LTE system. View full abstract»

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    A novel underlay TV spectrum sharing scheme based on polarization adaption for TD-LTE system

    Dongming Li ; Caili Guo ; Zhimin Zeng ; Xiaolin Lin
    Wireless Communications and Networking Conference (WCNC), 2013 IEEE

    DOI: 10.1109/WCNC.2013.6554951
    Publication Year: 2013 , Page(s): 2484 - 2489
    Cited by:  Papers (1)

    IEEE Conference Publications

    Spectrum opportunities in time, space and power domain are exploited by secondary users in traditional cognitive radio studies. While spectrum opportunities in polarization domain, namely simultaneous utilization of spectrum between primary and secondary system with polarization signal characteristics, is exploited inadequately. With the merits of polarization mismatch, primary system lies in the orthogonal polarized domain of secondary system, and interference to primary system can be mitigated. This work studies the cognitive underlay TV spectrum sharing with the merits of polarization mismatch for TD-LTE system. In this direction, a novel Polarized Underlay Spectrum Sharing (PUSS) scheme is proposed for the coexistence of TD-LTE and DTV system. It aims to characterize the spectrum efficiency of the cognitive radio setup while transmission of Polarization States (PSs) is affected by channel depolarization effect and interference constraint of DTV receiver is taken into account. Transmitting and receiving PSs are optimized by Particle Swarm Optimization with the polarized channel state information and primary PSs. Theoretical analysis and numerical results indicate that the proposed PUSS scheme could enable TD-LTE system share TV spectrum without causing much interference to incumbent DTV communication, while improvement in spectrum efficiency is achieved. View full abstract»

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    A monolithic LTE interleaver generator for highly parallel SMAP decoders

    Ilnseher, T. ; May, M. ; Wehn, N.
    Wireless Telecommunications Symposium (WTS), 2011

    DOI: 10.1109/WTS.2011.5960839
    Publication Year: 2011 , Page(s): 1 - 4
    Cited by:  Papers (2)

    IEEE Conference Publications

    The LTE standard specifies a throughput of 150MBit/s, while the upcoming true 4G LTE Advanced standard will push this throughput to 1 GBit/s. To achieve this throughput while fulfilling the low power requirements of mobile devices, future receiver circuit architectures need to deploy a high internal parallelism. The LTE standard has been designed with this parallelism in mind, using a QPP interleaver inside the turbo code decoder. In this paper we present a novel method to implement the QPP interleaver which significantly reduces power and area of this circuit. View full abstract»

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    Demonstration of an LTE portable network for private and emergency use - Introducing a fully distributed LTE network architecture

    Verin, G.
    Consumer Communications and Networking Conference (CCNC), 2014 IEEE 11th

    DOI: 10.1109/CCNC.2014.6994409
    Publication Year: 2014 , Page(s): 1146 - 1147

    IEEE Conference Publications

    Guaranteed and reliable access to mobile communications is important for consumers but it is fundamental for mission-critical business applications and in disaster recovery scenarios. During emergencies and events that gather many people in the same place, mobile networks typically become congested or even unavailable. Technologies such as WiFi, that operate on an unlicensed frequency spectrum, are affected by congestion and are susceptible to external interference that can make the technology unusable. Licensed frequencies are not subjected to interference but current solutions based on trasportable base stations (e.g. cells-on-wheels) that are dependent on backhaul connectivity cannot adequately serve the needs of mission critical communications. Mobile operator networks lack disaster recovery and congestion control mechanisms that allow the system to work even in case of a failure of key backhaul network links. Instead a private mobile network based on the latest cellular technology can deliver IP connectivity efficiently during emergencies, events and in general for mission critical communications. This demo shows how a private LTE network can offer privileged access to voice and video services for enterprise and government using standardized cellular technology. View full abstract»

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    Position Assisted Coordinate HARQ in LTE Systems for High Speed Railway

    Wantuan Luo ; Xuming Fang ; Shasha Li ; Yingying Xia
    Vehicular Technology Conference (VTC Spring), 2013 IEEE 77th

    DOI: 10.1109/VTCSpring.2013.6692716
    Publication Year: 2013 , Page(s): 1 - 5

    IEEE Conference Publications

    Voice over IP (VoIP) in LTE-R (LTE for Railway) will replace the circuit-switched (CS) voice service of the GSMR (GSM for Railway). However, it will face new problems in high speed railway scenario. In overlapping areas, the handover signaling (i.e. handover measurement and decision) is of higher priority than Hybrid Automatic Repeat reQuest (HARQ) retransmission so that the HARQ retransmission will be canceled when conflicts happen. If an user equipment (UE) is handed over to the target eNodeB (eNB), the HARQ retransmission or ACK/NACK of source eNB will not be received by the UE as normal, and the UE will wait for the potential retransmission and ACK/NACK. These particular problems will increase the VoIP packet error rate (PER) significantly. In order to solve these problems, a position assisted coordinate HARQ scheme in LTE system for high speed railway is proposed. With the help of trains position, the source eNB and target eNB share packets through coordination. If the handover is triggered, the UE will stop sending ACK/NACK. When the handover is completed, the UE sends the ACK of the last continuous packet to ensure lossless handover. Simulation results show that our proposal can reduce the VoIP PER in high speed railway scenario, and improve the system reliability, as well as VoIP capacity. View full abstract»

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    High efficiency wideband envelope tracking power amplifier with direct current sensing for LTE applications

    Myoungbo Kwak ; Jinseong Jeong ; Hassan, M. ; Yan, J.J. ; Kimball, D.F. ; Asbeck, P.M. ; Larson, L.E.
    Power Amplifiers for Wireless and Radio Applications (PAWR), 2012 IEEE Topical Conference on

    DOI: 10.1109/PAWR.2012.6174933
    Publication Year: 2012 , Page(s): 41 - 44
    Cited by:  Papers (3)

    IEEE Conference Publications

    A high efficiency wideband envelope tracking power amplifier for LTE applications is presented. The CMOS envelope amplifier with direct current sensing has a measured average efficiency of 78% with a 5 MHz LTE signal. The envelope tracking power amplifier including a GaAs HBT RF stage has overall power added efficiency (PAE) above 46% with an average LTE output power of 27.6 dBm and a gain of 26.5 dB. View full abstract»

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    Accurate SINR estimation model for system level simulation of LTE networks

    Ikuno, J.C. ; Pendl, S. ; Simko, M. ; Rupp, M.
    Communications (ICC), 2012 IEEE International Conference on

    DOI: 10.1109/ICC.2012.6364098
    Publication Year: 2012 , Page(s): 1471 - 1475
    Cited by:  Papers (3)

    IEEE Conference Publications

    This paper presents an SINR prediction model for LTE systems with the aim of improving the accuracy of physical layer models used for higher-than-physical-level simulations. This physical layer SINR abstraction for zero-forcing receivers takes channel estimation errors into account. It allows for the calculation of the post-equalization receive SINR of an LTE MIMO transmission on a per-layer and subcarrier basis. This estimate is further used as input for a link performance model to accurately predict the receiver throughput. The accuracy of the model is validated by simulations for 2×2 and 4×4 MIMO antenna configurations with different levels of spatial multiplexing employing also the precoding matrices defined in the LTE standard. Memory requirements and complexity for the model are quantified as well. The whole simulation environment together with the fully reproducible results of this paper are made available for download from our homepage. View full abstract»

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    Research Roadmap Driven by Network Benchmarking Lab (NBL): Deep Packet Inspection, Traffic Forensics, Embedded Benchmarking, 4G LTE, and Beyond

    Ying-Dar Lin
    Computing and Networking (CANDAR), 2013 First International Symposium on

    DOI: 10.1109/CANDAR.2013.7
    Publication Year: 2013 , Page(s): 1 - 7

    IEEE Conference Publications

    Most researchers look for topics from the literature. But my research has been driven mostly by development which in turn has been driven by industrial projects or lab works. We spanned into the areas of cable TV networks, multi-hop cellular, Internet QoS, deep packet inspection, traffic forensics, embedded benchmarking, and LTE. Among them, our multi-hop cellular work was the first along this line and has a high impact on both academia and industry, with over 600 citations and standardizations in WLAN mesh (IEEE 802.11s), WiMAX (IEEE 802.16j), Bluetooth (IEEE 802.15.5), and 3GPP LTE-advanced. Side products from our research include a startup (L7 Networks Inc., in 2002), a test lab (Network Benchmarking Lab, NBL, since 2002), and a textbook "Computer Networks: An Open Source Approach" (McGraw-Hill, 2011). It is a perfect time to report my 20-year research as we celebrate the 70th birthday of my Ph.D. thesis advisor, Prof. Mario Gerla. Inspired by his persistent and profound impacts, I think this is merely a half-time report and look forward to another 20 years of research. View full abstract»

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    Video capacity and QoE enhancements over LTE

    Singh, S. ; Oyman, O. ; Papathanassiou, A. ; Chatterjee, D. ; Andrews, J.G.
    Communications (ICC), 2012 IEEE International Conference on

    DOI: 10.1109/ICC.2012.6364806
    Publication Year: 2012 , Page(s): 7071 - 7076
    Cited by:  Papers (12)  |  Patents (1)

    IEEE Conference Publications

    Quality of Experience (QoE) has taken a center stage in the performance evaluation of multimedia delivery technologies. The Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) system is the latest generation of wireless cellular technology expected to deliver higher data rates and meet the burgeoning data demand. With the projected dominant share of video services in mobile traffic, providing satisfactory QoE to video users is a key objective for LTE system design. In this paper, we present a QoE-based evaluation methodology to assess the LTE system video capacity in terms of the number of unicast video consumers that can be simultaneously supported for a given target QoE. We define and use the notion of rebuffering outage capacity to quantify the video service capacity. Our evaluation further incorporates adaptive streaming, a promising technology for video delivery over wireless, and presents its consequent QoE-capacity tradeoff. The impact of QoE-based outage criteria is also investigated on the downlink video capacity. Finally, we propose a QoE-aware radio resource management (RRM) framework which allows the network operator to further enhance the video capacity. Our results demonstrate that there is a significant potential to optimize video capacity through QoE awareness both at the application level and radio access network (RAN) level. View full abstract»

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    Suppression of Cyclic Prefix in Down-Link LTE like Systems to Increase Capacity

    Prieto del Amo, C. ; Fernandez-Getino Garcia, M.J.
    Vehicular Technology Conference (VTC Spring), 2013 IEEE 77th

    DOI: 10.1109/VTCSpring.2013.6692775
    Publication Year: 2013 , Page(s): 1 - 5

    IEEE Conference Publications

    In this paper it is presented a proposal to increase the capacity of Down-Link (DL) transmissions in Long Term Evolution (LTE) like systems based on Multiple-Input Multiple-Output (MIMO)-Orthogonal Frequency Division Multiplexing (OFDM). The augment of the data rate is achieved with the total or partial suppression of the Cyclic Prefix (CP), which requires the use of a variable number of samples without conveying any information. The proposal is based on an iterative cancellation of the main impairments that the CP suppression supposes, the Inter Symbol and Inter Carrier Interferences. The interference mitigation procedure demands adequate channel estimations obtained in two different stages. Firstly, this new scheme requires the utilization of a preamble symbol appended to the beginning of the data transmission, which enables an initial Maximum Likelihood channel estimation. Secondly, time-variant channels will be estimated using a Least Squares estimator by the use of scattered pilots within the LTE frame structure. Through simulations it has been demonstrated that, despite the interferences arisen due to the CP suppression, our proposal attains adequate channel estimations which converge to theoretical bounds and the overall system obtains values of Bit Error Rate similar to the ideal situation of not suppressing the CP. It is also presented that considering the typical values of CP in the LTE standard the increment of the capacity employing this strategy can range between 7% and 25%. View full abstract»

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    Performance of well known packet scheduling algorithms in the downlink 3GPP LTE system

    Ramli, H.A.M. ; Basukala, R. ; Sandrasegaran, K. ; Patachaianand, R.
    Communications (MICC), 2009 IEEE 9th Malaysia International Conference on

    DOI: 10.1109/MICC.2009.5431383
    Publication Year: 2009 , Page(s): 815 - 820
    Cited by:  Papers (22)

    IEEE Conference Publications

    This paper investigates the performance of well known packet scheduling algorithms developed for single carrier wireless systems from a real time video streaming perspective. The performance evaluation is conducted using the downlink third generation partnership project long term evolution (3GPP LTE) system as the simulation platform. This paper contributes to the identification of a suitable packet scheduling algorithm for use in the downlink 3GPP LTE system supporting video streaming services. Simulation results show that, in the downlink 3GPP LTE system supporting video streaming services, maximum-largest weighted delay first (M-LWDF) algorithm outperforms other packet scheduling algorithms by providing a higher system throughput, supporting a higher number of users and guaranteeing fairness at a satisfactory level. View full abstract»

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    A 60% efficient envelope tracking power amplifier for 40W, 2.6GHz LTE base station with in/output harmonic tuning

    Tango, H. ; Hashinaga, T. ; Totani, K. ; Kuriyama, H. ; Hamada, Y. ; Asaina, T.
    Microwave Symposium Digest (IMS), 2013 IEEE MTT-S International

    DOI: 10.1109/MWSYM.2013.6697761
    Publication Year: 2013 , Page(s): 1 - 4

    IEEE Conference Publications

    This paper presents the results of the development of a highly efficient GaN HEMT-based envelope tracking (ET) Class-E power amplifier (PA) for 2.6GHz LTE base stations. This PA incorporates a unique harmonic tuning technique at both input and output to perform a wide frequency range operation. The fabricated internally-matched PA module exhibited a saturation output power level of 200W with 74% drain efficiency and 15dB gain. In combination with an ET modulator and digital pre-distorter (DPD), it was confirmed that our ET PA can achieve an average efficiency of over 60% and an adjacent carrier leakage ratio of -49dBc, which is, to the best of author's knowledge, the best performance of 2.6GHz LTE base station with a 40W average output power level. In the measurements, two carriers with 10MHz band LTE signal across 2.62-2.69GHz were used, where the peak to average power ratio (PAPR) was 6.5dB. View full abstract»

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    Licensed Shared Access (LSA) trial demonstration using real LTE network

    Palolo, M. ; Rautio, T. ; Matinmikko, M. ; Prokkola, J. ; Mustonen, M. ; Heikkila, M. ; Kippola, T. ; Yrjola, S. ; Hartikainen, V. ; Tudose, L. ; Kivinen, A. ; Paavola, J. ; Okkonen, J. ; Makelainen, M. ; Hanninen, T. ; Kokkinen, H.
    Cognitive Radio Oriented Wireless Networks and Communications (CROWNCOM), 2014 9th International Conference on

    Publication Year: 2014 , Page(s): 498 - 502

    IEEE Conference Publications

    This paper presents a demonstration of the new Licensed Shared Access (LSA) concept using a TD-LTE access network in the 2.3 GHz spectrum band in Finland. In the demonstrated trial, the TD-LTE network shares the spectrum of an incumbent spectrum user, who is focused on programme making and special events (PMSE) services. The demonstrator implements the new LSA concept and the required new building blocks including LSA Repository for spectrum protection information and LSA Controller for controlling the mobile communication network in the same band. The trial uses commercial network components like multiband-terminals, TD-L TE base stations, network management system, and core network. Spectrum usage data of incumbents is collected to LSA Repository using two incumbent user tools and is actively updated to LSA Controller for radio network planning to protect the incumbent's activity in the area. LSA Controller uses the information from the base stations and incumbents to protect incumbent spectrum users' rights. This is demonstrated by providing different algorithms, which analyze base stations and sectors that need to be reconfigured to prevent interference from LTE to incumbent (and vice versa). The demonstration shows that the new LSA concept can be implemented with existing network elements and a minimum amount of new components. View full abstract»

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    Energy-efficient and interference-aware handover decision for the LTE-Advanced femtocell network

    Xenakis, D. ; Passas, N. ; Merakos, L. ; Verikoukis, C.
    Communications (ICC), 2013 IEEE International Conference on

    DOI: 10.1109/ICC.2013.6654902
    Publication Year: 2013 , Page(s): 2464 - 2468
    Cited by:  Papers (1)

    IEEE Conference Publications

    Femtocells will play a key role for the wide adoption of the LTE-Advanced system, as they bring the access network closer to the end user in a cost-effective manner. This disruptive communication paradigm, however, dictates the use of advanced interference and mobility management algorithms to cope with the dense yet unplanned network layout. In this paper, we present an interference-aware handover decision algorithm for the LTE-Advanced femtocell network, which utilizes standard signal measurements to select the candidate cell that a) attains the minimum required channel gain for sustaining service continuity and b) minimizes the mean UE transmit power for a prescribed mean SINR target. The proposed algorithm attains backwards compatibility with the LTE-Advanced system, as it is deployed by using the private mechanism for non-standard use. Based on the evaluation methodology of the Small Cell forum, we validate the performance of the proposed algorithm and compare it against that of other state-of-the-art algorithms. View full abstract»

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    A dynamic Priority update Granularity adjustment algorithm based on user density and service delay requirement in LTE downlink scheduling

    Wenyu Li ; Li Jin ; Zhongfang Wang ; Lin Zhang ; Yu Liu
    Network Infrastructure and Digital Content (IC-NIDC), 2012 3rd IEEE International Conference on

    DOI: 10.1109/ICNIDC.2012.6418725
    Publication Year: 2012 , Page(s): 122 - 127
    Cited by:  Papers (1)

    IEEE Conference Publications

    LTE is a Long Term Evolution of wireless technology developed by 3GPP. In order to achieve the rapid growth of subscriber number and the ever increasing need for higher data rates, an ideal scheduling algorithm is needed for LTE system. In this article, we propose a new factor, Priority Upgrade Granularity (PUG), whose value influences the scheduling performance greatly. In addition, a dynamic PUG adjustment method according to user density and service delay requirement are presented. Numerous simulation results witness the increase in system throughput and user fairness compared with three widely used scheduling schemes, i.e. max C/I, Round Robin (RR) and Proportion Fair (PF). View full abstract»

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    Vulnerability Analysis of LTE Location Services

    Hofer, M. ; McEachen, J. ; Tummala, M.
    System Sciences (HICSS), 2014 47th Hawaii International Conference on

    DOI: 10.1109/HICSS.2014.635
    Publication Year: 2014 , Page(s): 5162 - 5166

    IEEE Conference Publications

    To meet government requirements for positioning emergency services, Long Term Evolution (LTE), the latest generation of mobile communications popular in North America and Europe, incorporates the ability to ascertain the position of the user equipment via the network. This additional signaling means that there is also the chance that the user position may be vulnerable to being intercepted by unauthorized parties. Several different potential vulnerabilities are explored in this paper and is a proof of concept for three vulnerabilities, including the presence of location data on the network when there is no authorized request for that data active. A series of simulations were constructed to analyze and test the logical flow of messages through the LTE core network and to see what vulnerabilities existed. The first simulation established a baseline, and each additional simulation examined a possible vulnerability. View full abstract»

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    An architecture for mobile computation offloading on cloud-enabled LTE small cells

    Lobillo, F. ; Becvar, Z. ; Puente, M.A. ; Mach, P. ; Lo Presti, F. ; Gambetti, F. ; Goldhamer, M. ; Vidal, J. ; Widiawan, A.K. ; Calvanesse, E.
    Wireless Communications and Networking Conference Workshops (WCNCW), 2014 IEEE

    DOI: 10.1109/WCNCW.2014.6934851
    Publication Year: 2014 , Page(s): 1 - 6

    IEEE Conference Publications

    Small cell networks are currently seen as a new way to satisfy the increasing wireless traffic demand. The proximity of base stations to subscribers brings many possibilities for the development of new applications, including new offerings based on cloud computing. Smartphones can directly offload applications to close base stations, provided that these are equipped with additional computational and storage resources. The cloud concept applied in the framework of small cells can also combine radio and computation aspects in order to optimise the service delivery. This paper introduces a new element called the Small Cell Manager (SCM), which optimises the overall operation of a cluster of cloud-enabled small cells. The SCM, aware of the cluster situation in terms of both radio and cloud aspects, interacts not only with the cloud-enabled base stations, but also with LTE core network components. To that end, different possibilities for the general architecture of a small-cell-cloud are analysed. Furthermore, the paper describes different evaluation criteria an LTE operator has to consider before adopting this approach in order to optimise the required investment and maximise benefits. View full abstract»

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    Neighbour list optimization for real LTE radio networks

    Duarte, D. ; Vieira, P. ; Rodrigues, A. ; Martins, A. ; Oliveira, N. ; Varela, L.
    Wireless and Mobile, 2014 IEEE Asia Pacific Conference on

    DOI: 10.1109/APWiMob.2014.6920278
    Publication Year: 2014 , Page(s): 183 - 187

    IEEE Conference Publications

    With the increasing complexity of current networks, it became evident the need for Self-Organizing Networks (SON), which aims to automate most of the associated radio planning and optimization tasks. Within SON, this paper aims to optimize the Neighbour Cell List (NCL) for Long Term Evolution (LTE) evolved NodeBs (eNBs). An algorithm composed by three decisions were were developed: distance-based, Radio Frequency (RF) measurement-based and Handover (HO) stats-based. The distance-based decision, proposes a new NCL taking account the eNB location and interference tiers, based in the quadrants method. The last two algorithms consider signal strength measurements and HO statistics, respectively; they also define a ranking to each eNB and neighbour relation addition/removal based on user defined constraints. The algorithms were developed and implemented over an already existent radio network optimization professional tool. Several case studies were produced using real data from a Portuguese LTE mobile operator. View full abstract»

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    Comparison of Policy Realization Strategies for LTE Networks

    Mir, U. ; Nuaymi, L.
    Vehicular Technology Conference (VTC Fall), 2012 IEEE

    DOI: 10.1109/VTCFall.2012.6399314
    Publication Year: 2012 , Page(s): 1 - 6
    Cited by:  Papers (2)

    IEEE Conference Publications

    Efficient radio resource usage and quality of service (QoS) provision are important criterions in order to choose the right QoS policy for the LTE operators. In our previous work, we have proposed to add a new database named as BSLRC (Base Station Load and Radio Conditions) to optimize the operator policy with regard to the radio efficiency. Some concrete voice capacity estimations were also proposed. In this paper, we extend our earlier work by addressing some novel concerns. As a first step, we start by calculating the signaling load due to the use of BSLRC. Then, for voice services the BSLRC method is compared with the explicit congestion notification (already proposed for LTE systems). Both BSLRC and ECN (Explicit Congestion Notification) share the same objective of optimizing the choice of codec rate with regard to radio use efficiency. We also propose some capacity estimates for video services as an extension to our previously proposed voice capacity estimations over LTE systems. View full abstract»

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    Optimized dual relay deployment for LTE-Advanced cellular systems

    Hamdi, A. ; El-Khamy, M. ; El-Sharkawy, M.
    Wireless Communications and Networking Conference (WCNC), 2012 IEEE

    DOI: 10.1109/WCNC.2012.6214291
    Publication Year: 2012 , Page(s): 2869 - 2873

    IEEE Conference Publications

    LTE-Advanced adopts relay deployment to support higher data rates and better coverage, especially at the cell edges which suffer from inter-cell interference. The solution of relaying is attractive because of its low cost and easy deployment. In this paper, we show that deploying just two relays per sector can significantly improve system capacity and coverage. We optimize the geometric deployment of relays that maximizes the spectral efficiency of the worst users or minimize outage. We consider the effects of different backhauling techniques such as wirelessly connected relays or wired radio remote heads. We also investigate the effect of different downlink frame structures and their impact on the system capacity or outage. The paper shows that the proper choice of the geometric deployment, frame structure and backhauling technique of the relays can improve the performance of LTE-Advanced. View full abstract»

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    UE performance evaluation on LTE indoor and outdoor testbeds

    Hung, J.-T.J. ; Chia-Yu Ku ; Hsiao-Chin Cheng ; Li-Ping Tung ; Lin, B.-S.P.
    Wireless and Pervasive Computing (ISWPC), 2013 International Symposium on

    DOI: 10.1109/ISWPC.2013.6707431
    Publication Year: 2013 , Page(s): 1 - 5

    IEEE Conference Publications

    As the ever increasing demands for higher data rate, lower system latency, and high speed in mobile communications, 4G/LTE systems widely deployed provide better support for these requirements. This increased the complexity of UE (user equipment) and eNBs (evolved Node B) structures, but with simplified core networks. A more flat architecture is achieved to raise data rate and low system latency that are appreciated by users using real-time or high throughput applications such as MAR (mobile augmented reality) or video game applications. The work introduces indoor and outdoor LTE (Long Term Evolution) testbeds for UE performance evaluation via IOT (interoperability) tests and field trials. Throughput for distinct UL-DL (uplink-downlink) configurations were measured to evaluate devices' performance. View full abstract»

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    System level performance evaluation of various carrier aggregation scenarios in LTE-advanced

    Chang Min Park ; Hae Beom Jung ; Song Hee Kim ; Duk Kyung Kim
    Advanced Communication Technology (ICACT), 2013 15th International Conference on

    Publication Year: 2013 , Page(s): 814 - 817
    Cited by:  Papers (1)

    IEEE Conference Publications

    The LTE-Advanced as an enhanced form of the LTE standardized at the 3GPP, is a promising technology for a higher spectral efficiency and reliable transmission. Carrier aggregation (CA) is the most important one among other technologies since it is difficult to ensure a single wide frequency band for operators. Despite active standardization of CA, little studies for system level performance have been made. This paper evaluates the performance of CA schemes in deployment scenarios 1 and 2 with different inter-site distances by using a LTE-A based system level simulator. Round robin and proportional fair schedulers are adopted for performance evaluation. The simulation results can help to provide an appropriate guideline for CA deployment and management in upcoming B4G mobile communications. View full abstract»

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    Third-order intermodulation product canceller for LTE base station receiver

    Kamizuma, H. ; Masuda, T. ; Onishi, M.
    Microwave Conference (EuMC), 2011 41st European

    Publication Year: 2011 , Page(s): 230 - 233

    IEEE Conference Publications

    This paper reports a low-IF receiver with a feedforward IM3 canceller for an LTE base station system. The proposed IM3 canceller utilizes a mixed-signal feed-forward path. The analog front-end of the feed-forward path, which detects an IM2 product for regeneration of an IM3 product, consists of only low frequency circuitry. Under IM3 cancellation, the receiver, which uses a dielectric duplexer in the RF front-end, achieves an effective IIP3 of 13 dBm and meets the LTE blocking requirement (IIP3 >; 11 dBm) with a 2 dB margin. View full abstract»

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    RF interference to DVB-T reception from multiple LTE devices in adjacent bands

    Sam, S. ; Biyanwilage, S. ; Gunawardana, U. ; Liyanapathirana, R.
    A World of Wireless, Mobile and Multimedia Networks (WoWMoM), 2014 IEEE 15th International Symposium on

    DOI: 10.1109/WoWMoM.2014.6919009
    Publication Year: 2014 , Page(s): 1 - 3

    IEEE Conference Publications

    In this paper, we study the compatibility of operating multiple Long Term Evolution (LTE) mobile handheld devices in the digital dividend spectrum identified in Australia. European studies provide some valuable insights on the operation of mobile services in the digital dividend, the results however do not provide a direct comparison due to difference in the DVB-T transmission band plan, the DVB-T channel bandwidth and the preferred duplexing arrangement. The European studies also only take into consideration compatibility of operating single LTE handheld devices in adjacent bands. Thus our study is into the impact of multiple LTE transmission on the DVB-T reception in the boundary of the Australian digital dividend using Monte Carlo simulations. View full abstract»

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    Stationary Transformation of Video Traffic in LTE Networks

    Albasheir, Suliman ; Kadoch, Michel
    Future Internet of Things and Cloud (FiCloud), 2014 International Conference on

    DOI: 10.1109/FiCloud.2014.62
    Publication Year: 2014 , Page(s): 351 - 355

    IEEE Conference Publications

    In recent years, digital communication and telecommunication have gained immense usage and introduced several innovative services (e.g. video conferencing, online banking, e-Health, etc) that change the life of people. By 2020, some telecommunication providers expect to have 50 Billion devices connected to each others. The whole world is getting closely connected with the new telecommunication technologies especially the Mobile broadband technology. The expectations indicate that not only human will be connected but also devices and machines will be connected communicating altogether through the Mobile broadband technology. These tremendous improvements in telecom will introduce new and innovative services that touch every small detail of people's life. Consequently, telecom networks will become more complex, involve more resources, and demand more requirements. Thus, network optimization will be crucial to avoid wasting the resources and ensure service availability and network efficiency. To help achieving that, network operators require intelligent methods to understand the ongoing traffic and services characteristics in order to control and forecast the live/ongoing traffic. In LTE networks, video traffic makes up the largest segment of data traffic. This paper discusses the video traffic characteristics in LTE networks, checks the stationarity status of the LTE video traffic and presents a method to transform the non-stationary LTE video traffic to stationary data. View full abstract»

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    3GPP LTE downlink scheduling strategies in vehicle-to-infrastructure communications for traffic safety applications

    Kihl, M. ; Bur, K. ; Mahanta, P. ; Coelingh, E.
    Computers and Communications (ISCC), 2012 IEEE Symposium on

    DOI: 10.1109/ISCC.2012.6249337
    Publication Year: 2012 , Page(s): 000448 - 000453

    IEEE Conference Publications

    Long Term Evolution (LTE) is the new generation of infrastructure-based wireless technologies that can be used for vehicular communications, and already a standard considered as the preliminary version of 4G mobile communications. It provides a cellular networks-based solution, generally called vehicle to infrastructure (V2I), for vehicular safety applications. In this work, we evaluate the performance of different downlink scheduling strategies under various urban and rural scenarios, in which voice, video and safety data traffic coexist. The traffic safety application scenarios we consider are variations of collision avoidance using LTE-based broadcast communication. Our main evaluation criteria are delay and packet loss rate. We present our findings for each scenario and compare the results. View full abstract»

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    W-AKA: Privacy-enhanced LTE-AKA using secured channel over Wi-Fi

    Hamandi, K. ; Sarji, I. ; Elhajj, I.H. ; Chehab, A. ; Kayssi, A.
    Wireless Telecommunications Symposium (WTS), 2013

    DOI: 10.1109/WTS.2013.6566240
    Publication Year: 2013 , Page(s): 1 - 6

    IEEE Conference Publications

    In this paper, we propose a privacy-enhanced LTE authentication and key agreement scheme, W-AKA. The scheme promises to improve privacy by employing a dynamic identity instead of the static IMSI. In order to exchange the IMSI and inform the user of the new randomized identity, we propose two methods. The first method uses a Wi-Fi secured side channel since Wi-Fi hotspots are becoming ubiquitous. The other method is incorporated as part of the mobile AKA. We also present a simple method through which a random temporary identity is generated. We studied the conditions where W-AKA outperforms the original AKA and where it underperforms. Our analysis shows that in the presence of Wi-Fi, and unless an attacker jams the Wi-Fi channel, W-AKA can sustain both active and passive attacks. On the other hand, in the absence of Wi-Fi, it can only mitigate risks of passive attacks. The difficulties and challenges of the proposed work are also analyzed. The scheme was implemented and compared with previously-published techniques in order to study the computational overhead to accomplish enhanced privacy. View full abstract»

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    A roadmap from UMTS optimization to LTE self-optimization

    Sallent, O. ; Pérez-Romero, J. ; Sánchez-González, J. ; Agusti, R. ; Díaz-guerra, M.A. ; Henche, D. ; Paul, D.
    Communications Magazine, IEEE

    Volume: 49 , Issue: 6
    DOI: 10.1109/MCOM.2011.5784003
    Publication Year: 2011 , Page(s): 172 - 182
    Cited by:  Papers (10)

    IEEE Journals & Magazines

    Self-Organizing Networks (SON) are currently being introduced by the 3rd Generation Partnership Project (3GPP) as part of the Long Term Evolution (LTE) system as a key driver for improving the operation of wireless networks. Given that many challenges have been identified when moving from the SON concept to practical implementation, this article claims the suitability to gain insight into the problem by taking advantage of optimization mechanisms in live Universal Mobile Telecommunications System (UMTS) networks. From that perspective, this article outlines a roadmap from actual manual optimization toward the inclusion of SON concepts in future networks. In particular, an optimization framework is developed considering different stages that include the collection of inputs from different sources (network counters, measurement reports, drive tests), the tuning parameters to achieve optimization, and the optimization procedure itself. Even though the proposed framework is presented and evaluated for convenience in a UMTS context, it is rather generic and technology-agnostic and, therefore, it can be formulated as an initial reference for LTE self-optimization use cases. The proposed framework is applied to a practical coverage optimization use case supported by data extracted from a real UMTS network in a European city, illustrating the capability to automatically identify a cell with sub-optimal coverage and to provide a solution to the problem. The extension of the case study to LTE is also analyzed. Finally, as a result of the lessons learned, the article makes a projection to the LTE context by identifying the key points to be solved for the materialization of a self-optimization procedure. View full abstract»

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    Comparison of MAC protocols between WiMAX and LTE

    Zhongmin Li ; Lu Gao ; Min Liu
    Circuits,Communications and System (PACCS), 2010 Second Pacific-Asia Conference on

    Volume: 2
    DOI: 10.1109/PACCS.2010.5626660
    Publication Year: 2010 , Page(s): 209 - 212

    IEEE Conference Publications

    WiMAX based on series of IEEE 802.16 standards and 3GPP LTE are the two important development directions of next generation broadband wireless communication. In physical layers, in order to transmit high speed data flow in limited bandwidth, they both use the OFDM technology and MIMO technology to enhance system capacity and frequency spectral efficiency, avoid inter symbol interference, and improve system performance. But, they have more different methods in design of MAC protocols and sublayer allocation of MAC functions. In this paper, we firstly introduce the MAC protocols in WiMAX 16e and 3GPP LTE Release 8. Then compare their MAC functions in control plane and data plane, and provide the comparison chart of MAC functions between WiMAX and LTE. It shows that they both provide the MAC basic functions though they have various differences in realization mechanism and function division. View full abstract»

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    Differential Precoding Scheme of LTE Systems over Temporally Correlated Channels

    Xun Li ; NoeYoon Park ; YoungJu Kim
    Vehicular Technology Conference (VTC Fall), 2011 IEEE

    DOI: 10.1109/VETECF.2011.6093045
    Publication Year: 2011 , Page(s): 1 - 5
    Cited by:  Papers (1)

    IEEE Conference Publications

    In this paper, a novel differential precoding scheme is proposed for LTE systems. The proposed scheme utilizes a differential codebook to update the precoding matrix. Due to the temporal correlation of adjacency time slots in temporally correlated channels, the current precoding matrix is restricted in a limited scope around the previous precoding matrix. This approach utilizes the differential information of the channel instead of quantizing the whole channel subspace, which involves less quantization distortion. The proposed precoding scheme has perfect compatibility with the conventional LTE precoding scheme. So, it has the good properties of LTE codebooks. We analyze the capacity and SER of the differential precoding scheme and compare the results with the performances of other existing precoding schemes. View full abstract»

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    Transmit diversity in LTE network

    Iordache, A.V. ; Marghescu, I.
    Telecommunications Forum (TELFOR), 2013 21st

    DOI: 10.1109/TELFOR.2013.6716193
    Publication Year: 2013 , Page(s): 145 - 148

    IEEE Conference Publications

    This paper investigate the effect of transmit diversity in LTE downlink transmission. Transmit diversity scheme known as Space Frequency Block Codes (SFBC) is considered. As performances metrics, the average BER is evaluated in terms of signal to interference-plus-noise ratio (SINR). We evaluate the channel estimation scheme for LTE downlink based on 3GPP LTE downlink specifications in presence of high Doppler deviations. Finally the accuracy and effectiveness of the theoretical analysis is verified by the simulation with idealized multipath channel models as well as the ITU pedestrian and vehicular channel with high order modulation and coding scheme. View full abstract»

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    Towards the efficient performance of LTE-A systems: Implementing a cell planning framework based on cognitive sensing

    Passas, V. ; Makris, N. ; Keranidis, S. ; Korakis, T. ; Tassiulas, L.
    Cognitive Cellular Systems (CCS), 2014 1st International Workshop on

    DOI: 10.1109/CCS.2014.6933813
    Publication Year: 2014 , Page(s): 1 - 5

    IEEE Conference Publications

    LTE and LTE-A have dominated as a 4G enabler protocol, adopted by the majority of the network providers worldwide. The efficient performance of an LTE network relies on the selected frequency within an operating band that the cell operates, by taking into account all the potential factors that can affect it. Since cognitive radio is targeting towards the maximization of spectrum utilization, it is crucial that it is adopted in the spectrum allocation process. In this work, we propose an efficient scheme for cell planning by employing spectrum sensing techniques. By exploiting spectral information collected by several sensing devices, we appropriately select the center frequency inside the operating band, towards maximizing the quality of the end user experience. Our algorithms are implemented for the downlink channel, considering a variety of configurations and topologies. Finally, our implemented mechanism is evaluated in the real world deployment of the NITOS Future Internet facility, using commercial LTE enabled femto cells and UEs, while USRP sensing devices are employed for high quality spectral information provisioning. View full abstract»

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    Optimal resource allocation in LTE-Advanced network using hybrid Cooperative Relaying and network coding

    Zainaldin, A. ; Halabian, H. ; Lambadaris, I.
    Communications (ICC), 2013 IEEE International Conference on

    DOI: 10.1109/ICC.2013.6654895
    Publication Year: 2013 , Page(s): 2427 - 2432

    IEEE Conference Publications

    Cooperative relaying (CoR) and network coding (NC) are two promising techniques for improving the performance of next generation LTE-Advanced networks. In this paper, a dynamic resource allocation scheme is proposed in relay-assisted LTE-Advanced networks which consists of three nodes: User Equipment (UE), Base Station or eNodeB (eNB) and an intermediate Relay Station (RS). In such a network, LTE UEs and eNB can choose between different transmission schemes: direct transmission, pure CoR (CoR scheme) using an intermediate relay station, or via the combination of Network Coding and Cooperative Relaying (NC/CoR scheme). We study the achievable rate regions for direct transmission, CoR and NC/CoR and it is noticed that NC/CoR does not always achieve better performance than CoR or direct transmission. Therefore, a hybrid transmission scheme with adaptive resource allocation is proposed to dynamically choose the best transmission scheme among NC/CoR, CoR or direct transmission. The proposed hybrid scheme determines the best transmission strategy and the optimal resource allocation decision at each bidirectional transmission time-frame based on the system channel information as well as the queue length information. The simulation results show that the hybrid algorithm significantly outperforms conventional schemes for both SISO and MIMO systems. View full abstract»

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    Experimental testbed for 5G cognitive radio access in 4G LTE cellular systems

    Danneberg, M. ; Datta, R. ; Festag, A. ; Fettweis, G.
    Sensor Array and Multichannel Signal Processing Workshop (SAM), 2014 IEEE 8th

    DOI: 10.1109/SAM.2014.6882406
    Publication Year: 2014 , Page(s): 321 - 324

    IEEE Conference Publications

    Cognitive radio technology addresses the limited availability of wireless spectrum and inefficiency of spectrum usage. Cognitive Radio (CR) devices sense their environment, detect spatially unused spectrum and opportunistically access available spectrum without creating harmful interference to the incumbents. In cellular systems with licensed spectrum, the efficient utilization of the spectrum as well as the protection of primary users is equally important, which imposes opportunities and challenges for the application of CR. This paper introduces an experimental framework for 5G cognitive radio access in current 4G LTE cellular systems. It can be used to study CR concepts in different scenarios, such as 4G to 5G system migrations, machine-type communications, device-to-device communications, and load balancing. Using our framework, selected measurement results are presented that compare Long Term Evolution (LTE) Orthogonal Frequency Division Multiplex (OFDM) with a candidate 5G waveform called Generalized Frequency Division Multiplexing (GFDM) and quantify the benefits of GFDM in CR scenarios. View full abstract»

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    Performance evaluation of LTE EPC self-healing solutions

    Rahman, M.M. ; Heydari, S.S.
    Globecom Workshops (GC Wkshps), 2012 IEEE

    DOI: 10.1109/GLOCOMW.2012.6477680
    Publication Year: 2012 , Page(s): 813 - 817

    IEEE Conference Publications

    The Long Term Evolution (LTE) defined by 3rdGeneration Partnership Project (3GPP) is a dominant cellular wireless technology which is currently being commercialized worldwide. In this paper, we evaluate the performance of self-healing schemes for LTE Evolved Packet Core (EPC) network elements failures in different architectural configurations. We also analyze message overhead and bandwidth requirements for the signaling traffic incurred by this design and its ramification to LTE core network. The simulation experiments are conducted to evaluate the performance of the self-healing schemes. View full abstract»

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    Dual-band printed asymmetric dipole antenna array for LTE applications

    Peng, C.-M. ; Chen, I.-F. ; Shen, S.-M. ; Lin, D.-B.
    Antennas and Propagation Society International Symposium (APSURSI), 2013 IEEE

    DOI: 10.1109/APS.2013.6711006
    Publication Year: 2013 , Page(s): 692 - 693

    IEEE Conference Publications

    In this article, a dual-band printed asymmetric dipole antenna array suitable for Long Term Evolution (LTE) standard is proposed. This antenna consists of two bent dipole antennas with V-shaped feeding structure, making it easy to combine omni-directional, multi-band and broad bandwidth. The optimized antenna exhibits a good impedance matching within the LTE bands at 700MHz and 1600MHz. The experimental results of the constructed prototype are provided. View full abstract»

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    A practical approach for base station on/off switching in green LTE-A HetNets

    Yaacoub, E.
    Wireless and Mobile Computing, Networking and Communications (WiMob), 2014 IEEE 10th International Conference on

    DOI: 10.1109/WiMOB.2014.6962165
    Publication Year: 2014 , Page(s): 159 - 164

    IEEE Conference Publications

    This paper describes a method for BS on/off switching in LTE-Advanced (LTE-A). The proposed method uses information exchanged between base stations (BSs) on the X2 interface in order to determine the BSs that should be switched on or off. It does not require centralized intelligence controlling the on/off switching in the network. Instead, it relies on always active coverage BSs that control the on/off switching of capacity BSs within their coverage area. Hence, it can be implemented locally in a distributed way. Simulation results show that the proposed switch off method can lead to significant energy savings in the network. View full abstract»

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    Practical Network Coding for Two Way Relay Channels in LTE Networks

    Hamdoun, H. ; Loskot, P. ; O'Farrell, T. ; Jianhua He
    Vehicular Technology Conference (VTC Spring), 2011 IEEE 73rd

    DOI: 10.1109/VETECS.2011.5956329
    Publication Year: 2011 , Page(s): 1 - 5
    Cited by:  Papers (3)

    IEEE Conference Publications

    In this paper, the implementation aspects and constraints of the simplest network coding (NC) schemes for a two-way relay channel (TWRC) composed of a user equipment (mobile terminal), an LTE relay station (RS) and an LTE base station (eNB) are considered in order to assess the usefulness of the NC in more realistic scenarios. The information exchange rate gain (IERG), the energy reduction gain (ERG) and the resource utilization gain (RUG) of the NC schemes with and without subcarrier division duplexing (SDD) are obtained by computer simulations. The usefulness of the NC schemes are evaluated for varying traffic load levels, the geographical distances between the nodes, the RS transmit powers, and the maximum numbers of retransmissions. Simulation results show that the NC schemes with and without SDD, have the throughput gains $0.5%$ and $25%$, the ERGs $7-12%$ and $16-25%$, and the RUGs $0.5-3.2%$, respectively. It is found that the NC can provide performance gains also for the users at the cell edge. Furthermore, the ERGs of the NC increase with the transmit power of the relay while the ERGs of the NC remain the same even when the maximum number of retransmissions is reduced. View full abstract»

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    LTE codebook capacity loss for single-cell multi-user MIMO channels

    Ahmad, A. ; Papathanassiou, A. ; Serpedin, E. ; Smith, P. ; Shafi, M.
    Personal Indoor and Mobile Radio Communications (PIMRC), 2012 IEEE 23rd International Symposium on

    DOI: 10.1109/PIMRC.2012.6362663
    Publication Year: 2012 , Page(s): 1902 - 1906

    IEEE Conference Publications

    Multi-user downlink MIMO communication has the potential to increase throughput using efficient beamforming. However, the precoding criteria assume perfect knowledge of the beamforming matrices at the base station (BS). This requires a user to transmit its complete channel information to the BS, a task that entails significant overhead. Limited feedback precoding, a part of LTE standardization now, needs only limited information be fed back to the BS. This paper studies the capacity loss incurred by using LTE codebooks, under different power allocation schemes with varying degrees of optimality. The sub-optimal power allocation schemes also ensure a better throughput-fairness trade-off. It is observed that using LTE codebooks results in a significant loss and that there is a need to develop codebooks which offer better adaptation to channel variations. View full abstract»

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    Capacity evaluation of Carrier Aggregation techniques in LTE-Advanced system

    Shayea, I. ; Ismail, M. ; Nordin, R.
    Computer and Communication Engineering (ICCCE), 2012 International Conference on

    DOI: 10.1109/ICCCE.2012.6271160
    Publication Year: 2012 , Page(s): 99 - 103
    Cited by:  Papers (1)

    IEEE Conference Publications

    In Long Term Evaluation (LTE)-Advanced system, Carrier Aggregation (CA) technique that provide substantial enhancement in data rate transmission for downlink and uplink over wider bandwidth have been proposed. The basic idea of CA technique is to aggregate several smaller contiguous or noncontiguous components, thus concurrent radio resources across multiple carriers are utilized. This paper overview CA technique including data aggregation schemes, bandwidth structure, and CA implementation in LTE-Advanced systems. A simulation model for LTE-Advanced in the downlink has been developed to investigate the impact of CA using up to five Component Carriers (CCs) on the system performance in terms of average throughput and number of active users per cell with respect to non-CA. Simulation show that CA improves the system performance in term of average user throughput within the cell coverage area as CCs increases. Furthermore, CA implementation can enhance the system capacity in term of number of active users in each cell. View full abstract»

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    Efficient location management mechanism for overlay LTE macro and femto cells

    Yixue Lei ; Yongsheng Zhang
    Communications Technology and Applications, 2009. ICCTA '09. IEEE International Conference on

    DOI: 10.1109/ICCOMTA.2009.5349167
    Publication Year: 2009 , Page(s): 420 - 424
    Cited by:  Papers (3)

    IEEE Conference Publications

    Femto cells will be adopted in LTE to provide indoor coverage, and CSG (closed subscriber group) will be supported for service provisioning. Due to potential huge number of femto cells and the impacts from CSG related functionalities, conventional location management may cause low efficiency in LTE deployment. This paper analyzes the technical issues and proposes an efficient location management mechanism for LTE femto cells considering the overlay macro cells. Performance analysis is conducted to demonstrate the effectiveness and advantages. The proposed mechanism can be applied to large scale deployment of LTE femto cells in the near future. View full abstract»

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    Resource Efficiency of Traffic-Centric Models for Complex LTE Systems

    Pileggi, P.
    Computational Intelligence, Modelling and Simulation (CIMSiM), 2012 Fourth International Conference on

    DOI: 10.1109/CIMSim.2012.11
    Publication Year: 2012 , Page(s): 357 - 362

    IEEE Conference Publications

    Simulation is the dominating method to model wireless communication systems, especially fourth generation (4G) wireless technologies, such as 3GPP long term evolution (LTE). However, orthodox simulation, i.e., discrete-event simulation (DES), has severe short-comings. It takes days, weeks, and even months, to produce sound performance estimates. As for 4G in general, LTE is connection-oriented. Including connection -- and packet-level activities in one model poses serious resource-requirement problems because the time-resolution of events at each respective level differs to the order of magnitude of at least 10E06. Consequently, Traffic-Centric Modelling (TCM) has been proposed as a feasible alternative to DES. In this paper, we present a TCM model of an LTE uplink scenario as proof-of-concept that TCM is, in fact, capable of modelling complex systems. Moreover, experimental results indicate a significant improvement in temporal and spatial resource-requirements achieved by TCM. View full abstract»

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    Implementation of LTE-R transceiver and the performance with WINNER D2a channel model

    Weihua Zhang ; Dongping Yao ; Meirong Yang
    Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications (MAPE), 2013 IEEE 5th International Symposium on

    DOI: 10.1109/MAPE.2013.6689852
    Publication Year: 2013 , Page(s): 704 - 708

    IEEE Conference Publications

    With the rapid development of high-speed railway, the train speed can reach up to 350 km/h. Much more technical demands for high-speed railway mobile communication system are put forward. As the next generation wireless communication technology of 3GPP, Long Term Evolution for railway, known as LTE-R, is proposed to provide railway communication services including railway control, passenger services, wireless surveillance video, etc. The main goal of this paper is to evaluate the detailed performance of LTE-R on the WINNER D2a channel model which has been presented as an appropriate choice for the wireless channel model in high-speed scenario, and implement a LTE-R transceiver based on LabVIEW software and National Instruments Universal Software Radio Peripheral 2920 (NI USRP2920) platform for further research. The experimental results show that LTE-R has promising potential to be used in high-speed railway scenario. View full abstract»

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    Predictive connection time based small cell discovery strategy for LTE-advanced and beyond

    Yateng Hong ; Xiaodong Xu ; Mingliang Tao
    Wireless Communications and Networking Conference (WCNC), 2014 IEEE

    DOI: 10.1109/WCNC.2014.6952607
    Publication Year: 2014 , Page(s): 2061 - 2066

    IEEE Conference Publications

    In LTE-Advanced (LTE-A) and beyond networks, deploying complementary small cells on an existing macro layer is recognized as an attractive solution to improve the network capacity and provide seamless broadband services in local areas. However, existing cell discovery mechanism is tailored for homogeneous networks (macro only). User Equipment (UE) can't energy-efficiently detect the small cells on a dedicated carrier or maximally exploit the offloading opportunities provided by such heterogeneous deployments. In this paper, we propose a Predictive Connection time based Inter-frequency Measurement (PCIM) solution to cope with the problems. With the aid of the positioning results, the small cell connection time is derived, both user velocity and moving direction are taken into account. Using 3rd Generation Partnership Project (3GPP) LTE-A Heterogeneous Network (HetNet) mobility evaluation methodology, the proposed PCIM scheme is compared with some currently standardized techniques. Simulation results provide insights on the small cell discovery schemes in terms of energy efficiency and small cell usage efficiency, and demonstrate the benefits of the proposed PCIM scheme over the other alternatives. View full abstract»

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    A highly-efficient BiCMOS cascode Class-E power amplifier using both envelope-tracking and transistor resizing for LTE-like applications

    Yan Li ; Ruili Wu ; Lopez, J. ; Lie, D.Y.C.
    Bipolar/BiCMOS Circuits and Technology Meeting (BCTM), 2011 IEEE

    DOI: 10.1109/BCTM.2011.6082767
    Publication Year: 2011 , Page(s): 142 - 145
    Cited by:  Papers (1)

    IEEE Conference Publications

    This paper presents the design of a SiGe differential cascode power amplifier (PA) to perform the envelope-tracking (ET) along with transistor resizing for efficiency enhancement for the 16QAM LTE. A new parallel-circuit class-E PA model is developed to analyze and design the cascode PA. The analytic results are compared with SPICE simulation and measurement data to provide circuit design insights. Measurement shows the ET-based PA system reaches an overall power-added-efficiency (PAE) of 38% at its 1 dB compression point (P1dB) of 22 dBm for its high power mode. Additionally, at the low power mode, some of the transistor cells can be disabled by the integrated MOSFET switches, and the overall PAE is improved by 4-5% at ≥4 dB back-off from its P1dB. This ET-based cascode PA satisfies the LTE 16QAM linearity specs without needing predistortions. View full abstract»

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    A recursive PRB allocation algorithm using AMC for MIMO-OFDMA LTE systems

    Ben Hassen, W. ; Afif, M. ; Tabbane, S.
    Systems, Signals & Devices (SSD), 2013 10th International Multi-Conference on

    DOI: 10.1109/SSD.2013.6564021
    Publication Year: 2013 , Page(s): 1 - 6

    IEEE Conference Publications

    3GPP LTE is a suitable candidate for high quality wireless communication insurance according to the mobile users' requirements thanks to its radio link flexibility using Adaptive Modulation and Coding (AMC), Multiple Input Multiple Output (MIMO) and Orthogonal Frequency Division Multiple Access (OFDMA) technologies. This paper addresses the resource allocation optimisation problem aiming to guarantee a high spectral efficiency promised over the LTE-downlink network. Therefore, we propose here a recursive Physical Resource Bloc (PRB) allocation algorithm is developed in this paper. In this context, we use the Effective Signal-to-Interference-plus-Noise Ratio (ESINR) metric to properly characterize multi-state channels conditions. Then, the basic idea of the proposed algorithm is to allocate to each mobile user its best PRB according to the highest measured ESINR in order to ensure the maximum system capacity. Simulations results show that the proposed algorithm provides better performance in terms of system capacity than other recent works thanks to its recursion procedure. View full abstract»

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    Edge-prioritized channel- and traffic-aware uplink Carrier Aggregation in LTE-advanced systems

    Sivaraj, R. ; Pande, A. ; Kai Zeng ; Govindan, K. ; Mohapatra, P.
    World of Wireless, Mobile and Multimedia Networks (WoWMoM), 2012 IEEE International Symposium on a

    DOI: 10.1109/WoWMoM.2012.6263691
    Publication Year: 2012 , Page(s): 1 - 9
    Cited by:  Papers (6)

    IEEE Conference Publications

    LTE-Advanced (LTE-A) systems support wider transmission bandwidths and hence, higher data rates for bulk traffic, as a result of Carrier Aggregation (CA). However, existing literature lacks efforts on channel-aware CA, especially in the uplink. The cell-edge users particularly suffer from exhaustion of resources, higher fading losses, lower SINR values (hence, requiring a higher power consumption) due to lossy channels that their traffic requirements are least-satisfied by channel-blind CA. This paper addresses the above concern by proposing an edge-prioritized channel- and traffic-aware uplink CA comprising Component Carrier (CC) assignment and resource scheduling. The LTE-A UEs are spatially-grouped and the under-represented edge UE groups, having the least assignable resources (good CCs), are prioritized for CA. This results in assigning the best channels to the edge groups. The frequency resources are scheduled to the groups based on inter-group and intra-group Proportional Fair Packet Scheduling (PFPS) in the time and frequency domains respectively, to resolve resource contention. The proposed approach outperforms the existing channel-blind Round-Robin and channel-aware Opportunistic CA, in terms of overall uplink throughput, by 33% in CC assignment and 21% in PFPS, in addition to significant throughput improvements for the edge UEs. View full abstract»

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    WiFi Direct and LTE D2D in action

    Asadi, A. ; Mancuso, V.
    Wireless Days (WD), 2013 IFIP

    DOI: 10.1109/WD.2013.6686520
    Publication Year: 2013 , Page(s): 1 - 8

    IEEE Conference Publications

    With the evolution of high-performance multi-radio smartphones, Device-to-Device (D2D) communications became an attractive solution for enhancing the performance of cellular networks. Although D2D communications have been widely studied within past few years, the majority of the literature is confined to new theoretical proposals and did not consider implementation challenges. In fact, the implementation feasibility of D2D communications and its challenges are still a relevant research question. In this paper, we introduce a protocol that focuses on D2D communications using LTE and WiFi Direct technologies. We also show that currently available WiFi Direct features permits to deploy the D2D paradigm on top of the LTE cellular infrastructure, without requiring any fundamental change in LTE protocols. View full abstract»

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    Non-regular network performance comparison between HSDPA and LTE

    Puttonen, J. ; Repo, I. ; Aho, K. ; Nihtila, T. ; Kurjenniemi, J. ; Henttonen, T. ; Moisio, Martti ; Chang, K.
    Wireless Pervasive Computing (ISWPC), 2010 5th IEEE International Symposium on

    DOI: 10.1109/ISWPC.2010.5483790
    Publication Year: 2010 , Page(s): 568 - 572

    IEEE Conference Publications

    In this paper we study and benchmark the performance of 3rd Generation Partnership Project (3GPP) High Speed Downlink Packet Access (HSDPA) and 3GPP Long Term Evolution (LTE) Downlink with constant bit rate type traffic. In addition a non-regular simulation scenario is considered using realistic propagation data and base station positions related to Tokyo city downtown area. HSDPA was introduced in 3GPP Release 5 and in further releases the technology has been improved with e.g. receive and transmit diversity technologies and support for higher order modulation schemes. LTE was introduced in 3GPP Release 8 with completely new physical layer and improved Radio Resource Management (RRM) functionalities. The benchmarking is performed with fully dynamic system level simulators based on detailed and commonly accepted models for e.g. mobility, propagation, call generation and fading. The results show that LTE Release 8 outperforms HSDPA Release 8 in terms of spectral efficiency and user throughput. With 8 UEs per cell and LTE MIMO about 90% of UEs are fully satisfied, while about 45% of the UEs are fully satisfied with HSDPA MIMO. This results also about 30% gain in spectral efficiency even through with LTE the network is running half empty due to uneven UE distribution in non-regular network with variable cell sizes. View full abstract»

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    Performance evaluation of coordinated multipoint reception in CRAN under LTE-Advanced uplink

    Yuan Huiyu ; Zheng Naizheng ; Yan Yuyu ; Skov, P.
    Communications and Networking in China (CHINACOM), 2012 7th International ICST Conference on

    DOI: 10.1109/ChinaCom.2012.6417589
    Publication Year: 2012 , Page(s): 778 - 783

    IEEE Conference Publications

    Coordinated Multipoint Processing (CoMP) is a promising method to improve cell edge data rate and system spectrum efficiency, which helps LTE-Advanced to meet the high data rate requirement of 4G mobile communication networks. In uplink, coordinated multipoint reception is transparent to user equipment, while significant gain can be achieved with coordination of multiple base stations. CoMP gain can be affected by network deployment, receiver algorithm, channel estimation accuracy and orthogonality of reference signals. In this article, we focuses on uplink CoMP reception in 3GPP long term evolution advanced (LTE-A). Deployment scenarios are introduced in both homogenous networks and heterogeneous networks. Evaluation are taken under system level simulation. Receiver schemes, realistic channel estimation, and impact of reference signals orthognality is taken into consideration. Performance improvement are shown and compared in different CoMP scenarios. View full abstract»

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    Enhanced Frequency Diversity Exploitation in Carrier Aggregation for LTE-Advanced Systems

    Wenxun Qiu ; Minn, H. ; Chia-Chin Chong
    Vehicular Technology Conference (VTC Fall), 2011 IEEE

    DOI: 10.1109/VETECF.2011.6092881
    Publication Year: 2011 , Page(s): 1 - 6

    IEEE Conference Publications

    LTE-Advanced systems have adopted the concept of Carrier Aggregation (CA) to meet the data rate requirements of IMT-Advanced systems. The CA approach opens up several new implementation challenges as well as opportunities for further performance improvement. Existing works on CA focus on implementation issues, but exploitation of CA-specific features for performance improvement has not been addressed yet. In this paper, we fill this gap and investigate the enhanced frequency diversity exploitation in CA based systems. New interleaving schemes for both downlink OFDMA and uplink SC-FDMA of LTE-Advanced systems are proposed to capture CA-specific enhanced frequency diversity with simple implementation. The proposed schemes also provide full backward compatibility with the LTE system. Performance evaluation via simulation in a simplified LTE system environment corroborates that the proposed approach provides performance advantages in both downlink and uplink. View full abstract»

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    Radix-4 Max-log-MAP parallel turbo decoder architecture with a new cache memory data flow for LTE

    Adiono, T. ; Marvin
    Intelligent Signal Processing and Communications Systems (ISPACS), 2012 International Symposium on

    DOI: 10.1109/ISPACS.2012.6473599
    Publication Year: 2012 , Page(s): 792 - 797

    IEEE Conference Publications

    This paper presents a design of turbo decoder VLSI arcitecture based on 3GPP-LTE standard. In order to meet the LTE peak data rate of 326.4 Mbps, parallelization of the MAP decoder and Max-log-MAP radix-4 decoding algorithm are utilized in this work. A thorough analysis of how the MAP decoder work in parallel is presented. We describe the data dependency between each MAP decoder and hazard that cames from the usage of parallelization, in which we modify the data flow and architecture of the branch/transition metric cache memory to increase the concurrency of parallelization method and eliminate the hazard. Proposed design has a maximum throughput of 347.8 Mbps. View full abstract»

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    Turbo equalization for LTE uplink under imperfect channel estimation

    Ting Li ; Wenjin Wang ; Xiqi Gao
    Personal, Indoor and Mobile Radio Communications, 2009 IEEE 20th International Symposium on

    DOI: 10.1109/PIMRC.2009.5450034
    Publication Year: 2009 , Page(s): 330 - 334
    Cited by:  Papers (3)

    IEEE Conference Publications

    Single-carrier frequency division multiple access (SC-FDMA) has appeared to be a promising technique for high data rate communication in Long Term Evolution (LTE) uplink. In this paper, we propose an improved turbo equalizer for multiuser multiple-input multiple-output (MU-MIMO) LTE uplink to enhance the performance as the channel statement information is imperfect at the receiver. we derive the optimal soft-input soft-output (SISO) detector in turbo equalizer based on minimum mean square error (MMSE) criterion under imperfect channel estimation by concerning the statistical characteristic of the channel estimation error. It can be implemented in frequency-domain and almostly cause no increase in computational complexity compared to the conventional turbo equalizer for SC-FDMA. Simulation results for LTE scenario demonstrate that the proposed turbo equalizer yields 0.8-1.0dB gain to the turbo receiver which does not consider the imperfect CSI when channel estimation errors exist. View full abstract»

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    A frequency domain joint MMSE-SIC equalizer for MIMO SC-FDMA LTE-A uplink

    Sah, B. ; Surendar, M. ; Muthuchidambaranathan, P.
    Electronics and Communication Systems (ICECS), 2014 International Conference on

    DOI: 10.1109/ECS.2014.6892727
    Publication Year: 2014 , Page(s): 1 - 4

    IEEE Conference Publications

    Single carrier frequency division multiple access (SC-FDMA) has been adopted as the air interface for the uplink transmission in 3GPP long term evolution (LTE) and long term evolution advanced (LTE-A) systems because it has low peak-to-average power ratio (PAPR). The performance of SC-FDMA system degrades in frequency selective fading channel because of the use of single carrier. Also, the performance of SC-FDMA system degrades when the orthogonality among subcarriers is lost due to the presence of carrier frequency offsets (CFOs) in the channel. In this paper, we have proposed a joint minimum mean squared error (JMMSE) successive interference cancellation (SIC) equalizer scheme that performs the frequency domain equalization (FDE) as well as the CFOs compensation jointly for multiple input multiple output (MIMO) SC-FDMA based LTE-A uplink system. The bit error rate (BER) performances of MMSE-FDE and JMMSE-SIC equalizers have been compared and the simulation results show that the proposed equalizer performs better than the MMSE-FDE equalizer for multi-user (MU) MIMO SC-FDMA system. View full abstract»

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    Performance analysis of intercell interference coordination in downlink FDD-LTE system

    Setiawan, I. ; Iskandar
    Telecommunication Systems, Services, and Applications (TSSA), 2012 7th International Conference on

    DOI: 10.1109/TSSA.2012.6366064
    Publication Year: 2012 , Page(s): 261 - 265

    IEEE Conference Publications

    Frequency reuse schemes used in LTE network planning are optimized using inter-cell interference coordination with soft frequency reuse. The parameters needed in planning LTE network is derived from the process of dimensioning, including capacity and coverage. By using conventional reuse systems, such as systems reuse one and three, the simulation results obtained do not meet network specifications issued by the 3GPP LTE, requiring repair system using soft frequency reuse. From the results of simulations, the CINR level and throughput generated through soft frequency reuse scheme is better than reuse one and three, where there is an improvement on the performance of cell edge users that has been frequently experiencing interference issues. View full abstract»

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    Planning and control of LTE femto networks

    Lau, R. ; Zhang, T.
    Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt), 2011 International Symposium on

    DOI: 10.1109/WIOPT.2011.5930057
    Publication Year: 2011 , Page(s): 423 - 427

    IEEE Conference Publications

    Adaptation of LTE femtocell transmission power levels in a distributed architecture to meet performance requirements is crucial for successful femtocell network deployment. System stability, scalability, robustness, and controllability must be addressed before large scale deployment. This paper proposes and analyzes a new method for dynamically adjusting LTE femtocell power levels to mitigate interference to meet user selectable network performance goals. The paper proves that the proposed method converges to feasible solutions. The proposed algorithm is suitable for both distributed femtocell control and centralized policy enforcement. View full abstract»

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    Effects of SINR estimation errors on the DL cell throughput of an LTE system in different environments

    Ostermayer, G. ; Neumeier, R. ; Eder, S.
    Communications (MICC), 2013 IEEE Malaysia International Conference on

    DOI: 10.1109/MICC.2013.6805824
    Publication Year: 2013 , Page(s): 196 - 201

    IEEE Conference Publications

    In this paper we analyze the influence of errors in SINR estimation on the system level performance of an LTE system. Additionally we investigate the effect of the selection of the SINR/CQI mapping curve on the cell throughput and error resistance. We focus on downlink scenarios in a macro-cell (57 cells deployed in a hexagonal grid) and a micro-cell environment (Manhattan grid deployment with 72 cells). Up to 20 users are simultaneously active in the observed cell. For that we use a Best CQI scheduling algorithm. Our investigations are done using a simulation environment based on two tools with different modeling accuracy. With that approach the simulation runtime can be kept short enough in order to produce results efficiently. Simulations have shown that the LTE system is very resistant to SINR estimation errors, but it does not always achieve the best cell throughput performance when operating with the parameters for the SINR-to-modulation-and-coding curves recommended in the LTE-standard documents [1]. However, by increasing cell throughput performance, the resistance to SINR estimation errors decreases. View full abstract»

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    Dynamic spectrum allocation in Femto based LTE network

    Sathya, R.V. ; Tamma, B.R.
    Communication Systems and Networks (COMSNETS), 2013 Fifth International Conference on

    DOI: 10.1109/COMSNETS.2013.6465585
    Publication Year: 2013 , Page(s): 1 - 2
    Cited by:  Papers (1)

    IEEE Conference Publications

    3GPP has introduced LTE Femto cells to handle the traffic for indoor users and to reduce the load on the Macro cells. However, the current LTE Femto based system is not able to utilize the spectrum efficiently. Hence, we propose a new spectrum allocation method which dynamically allocates the spectrum between Macro and Femto cells and dynamically inside Femto regions based on user traffic demands. This method is applicable only for enterprise cellular deployments in which, all Femtos are deployed in a planned manner. View full abstract»

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    Using cognitive radio interference mitigation technique to enhance coexistence and sharing between DVB-T and LTE system

    Sangtarash, S. ; Sadeghi, H. ; Hassan, W.A. ; King, H.L. ; Rahman, T.A.
    Future Network & Mobile Summit (FutureNetw), 2012

    Publication Year: 2012 , Page(s): 1 - 9
    Cited by:  Papers (1)

    IEEE Conference Publications

    Today with increasing development of wireless systems, frequency utilization is limited by the problem of insufficient spectrum. In addition with increasing the implementation of the third generation (3G) and integrated cellular phones that provide high speed packet-switching data transmission, we need more portion of spectrum. On the other hand analogue TV is moving to digital, so after this switch-over, there are some parts of the spectrum which will be free, and may be able to be used for other services. In this study we try to use the technology that is able to sense the spectrums over the DVB-T frequency band (primary system), and detect the existence/absence of primary users, and based on the detection of free spectrum, use that spectrum for LTE system as a secondary system, without harmful interference with primary users defined as Cognitive Radio (CR). Our study has shown that for coexistence and sharing between DVB-T and LTE-OFDM, at the same frequency band (662-742 MHz), the probability of interference is high and a large protection guard distance is needed. However when we apply Cognitive Radio technique, harmful interference can be avoided from secondary systems and improve spectrum efficiency. View full abstract»

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    Advanced receivers for downlink MIMO in LTE network

    Visoz, R. ; El Rawas, Z. ; Landre, J.-B.
    Wireless and Mobile Computing, Networking and Communications (WiMob), 2013 IEEE 9th International Conference on

    DOI: 10.1109/WiMOB.2013.6673423
    Publication Year: 2013 , Page(s): 630 - 637

    IEEE Conference Publications

    In MIMO LTE Networks, closed loop link adaptation together with precoding matrix selection try to reduce the interference at the receiver side while maximizing the data rate for a given QoS. However, due the constraints of limited feedback and finite size precoding codebooks, the residual spatial layer interference remains a major impediment to reach high spectral efficiency. The aim of this paper is to evaluate for LTE downlink both at link and system levels the potential gain of non linear receivers with respect to their Linear Minimum Mean Square Error (LMMSE) counterpart. Within the considered 4×4 MIMO LTE network, adopting a Cyclic Redundancy Check (CRC) based Successive Interference Cancellation receiver potentially improves the average rate by 5% and 10% in peak and off-peak traffic hours, respectively. However, the interference-free upper bound promises a gain of 45% and 60% for the same load conditions. These results militate for the adoption of more sophisticated receivers, e.g., turbo-SIC, for large MIMO systems. View full abstract»

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    A distributed, load-aware, power and frequency bargaining protocol for LTE-based networks

    Angelakis, V. ; Sajid, M. ; Siddiqui, I. ; Yuan, D.
    Communications (ICC), 2012 IEEE International Conference on

    DOI: 10.1109/ICC.2012.6364818
    Publication Year: 2012 , Page(s): 6525 - 6529

    IEEE Conference Publications

    A distributed, load-aware, joint power and frequency allocation protocol is introduced for LTE-based cellular networks, and system-level simulations are performed. Our proposed scheme aims to cooperatively limit the impact of Fractional Frequency Reuse (FFR) on the center users' throughput compared to the Reuse 1 scheme, while providing sufficient throughput for the edge users. This is achieved through an asynchronous, lightweight scheme of local message exchange between neighboring LTE eNodeBs. The proposed scheme facilitates a type of “bargain” where an overloaded sector requests permission to utilize its neighbors' edge bands for its center users at a limited set of transmit power levels. Grants are generated at each neighbor by solving a small-scale optimization problem. Using an LTE simulator we evaluate our scheme on a network with 21 sectors of varying load patterns. The proposed scheme's performance for center users is consistently improved with respect to FFR-3, while for edge users the performance degradation is controlled by a parameter we set in the optimization problems' definitions; compared to Reuse 1 edge users still have gains. Specifically, we observed up to a 46% gain in the sectors' center throughput with a cost below 9% at the edges when compared to the classic FFR scheme, while the overall system throughput goes up by up to 26% in heavily loaded scenarios. View full abstract»

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    Analysis of Throughput Performance Statistics for Benchmarking LTE Networks

    Buenestado, V. ; Ruiz-Aviles, J.M. ; Toril, M. ; Luna-Ramirez, S. ; Mendo, A.
    Communications Letters, IEEE

    Volume: 18 , Issue: 9
    DOI: 10.1109/LCOMM.2014.2337876
    Publication Year: 2014 , Page(s): 1607 - 1610

    IEEE Journals & Magazines

    In this letter, a comprehensive analysis of throughput performance statistics in a live LTE network is presented. The analysis shows the relationship between several widely accepted throughput performance indicators, i.e., the user throughput, the cell throughput, and the radio link throughput, and how these indicators are related to signal quality statistics. The analysis is performed on a per-cell and per-connection basis. For this purpose, throughput and signal quality statistics are collected from network performance counters and call traces in cells of a live LTE system. Results show that all throughput measures are strongly affected by chatty applications dominating current LTE networks due to the last transmission time interval transmissions and the outer loop link adaptation mechanism. View full abstract»

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    Analysis of interference signal from LTE phone on sound systems

    Suna Choi ; Seungkeun Park
    ICT Convergence (ICTC), 2013 International Conference on

    DOI: 10.1109/ICTC.2013.6675490
    Publication Year: 2013 , Page(s): 826 - 830

    IEEE Conference Publications

    Intermittent or periodic signals of mobile devices cause interference at audible frequency to the sound system. In this regard, it is recently issued that the intermittently transmissions of long term evolution (LTE) mobile phones cause the interference noises on sound systems, similar to that of global system for mobile communication (GSM) mobile phones. For retaining the immunity from noises, international regulations suggests a 1kHz amplitude modulation (AM) 80% and GSM modulation signal as reference signals for immunity test of sound and television broadcast receiver. In this paper, the effects of interference noise of LTE is compared with that of AM and GSM, and the LTE noise is evaluated as the reference signal for international immunity test of sound systems. View full abstract»

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    A high-efficient 3-D Nefer-antenna for LTE communication on a car

    Goncharova, I. ; Lindenmeier, S.
    Antennas and Propagation (EuCAP), 2014 8th European Conference on

    DOI: 10.1109/EuCAP.2014.6902527
    Publication Year: 2014 , Page(s): 3273 - 3277

    IEEE Conference Publications

    In this article a new antenna for Long Term Evolution (LTE) communication technology for automotive application is presented. It is designed to be set on the roof of a car underneath a standard plastic cover. Even though the antenna operates at a wide frequency band (from 698 MHz to 960 MHz and from 1470 MHz to 2700 MHz) in small mounting volume, the antenna requires no matching network. It obtains the demanded omnidirectional radiation pattern within all the above mentioned LTE frequency bands. A low-loss panel design enables a high efficiency of the antenna. The antenna properties are shown via simulation and measurement results of a functional demonstrator. View full abstract»

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    LTE-advanced carrier aggregation supporting fully standard 3GPP MIMO by optical polarization multiplexing

    Morant, M. ; Llorente, R. ; Prat, J.
    Optical Fiber Communications Conference and Exhibition (OFC), 2014

    Publication Year: 2014 , Page(s): 1 - 3

    IEEE Conference Publications

    LTE-A carrier aggregation investigation demonstrates successful 2×2 MIMO Pol-Mux RoF transmission of five LTE-A carriers modulated in 16QAM in 25 km, three LTE-A carriers in 75 km and an LTE carrier in 100 km SSMF. View full abstract»

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    Analysis of LTE and DC-HSDPA performance with variable number of users per TTI in macro cellular network

    Sheikh, M.U. ; Lempiäinen, J.
    Wireless Communications and Mobile Computing Conference (IWCMC), 2012 8th International

    DOI: 10.1109/IWCMC.2012.6314338
    Publication Year: 2012 , Page(s): 979 - 983

    IEEE Conference Publications

    Data traffic has significantly increased in the past years, and it is expected to grow even at higher pace. Long Term Evolution (LTE) technology and the concept of Dual-Cell High Speed Downlink Packet Access (DC-HSDPA) were introduced to serve the data users. The target of this paper is to analyse the impact of serving variable number of users per Transmission Time Interval (TTI) on the performance of LTE along with different antenna configuration and DC-HSDPA system with and without Power Control (PC). In this paper average cell throughput, relative throughput gain, and user's probability of no data transfer with different Intersite Distance (ISD) was analyzed in macro cellular environment. Simulation results revealed that average cell throughput decreases with the increase in both ISD and active number of users per TTI. But, LTE throughput was found to be more sensitive with the change in ISD, whereas DC-HSDPA throughput affects more with the change in serving number of users per TTI. DC-HSDPA with PC was found to offer lower probability of no data transfer compared to LTE regardless of ISD and active number of users. View full abstract»

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    Analyzing mobile applications and power consumption on smartphone over LTE network

    Gupta, M. ; Koc, A.T. ; Vannithamby, R.
    Energy Aware Computing (ICEAC), 2011 International Conference on

    DOI: 10.1109/ICEAC.2011.6403623
    Publication Year: 2011 , Page(s): 1 - 4

    IEEE Conference Publications

    The explosive number of applications now available on smart phone type of devices and the availability of high-speed mobile broadband connectivity through 4G networks such as LTE has only increased the challenges in improving battery life of these devices. In this paper, we illustrate the 4G power consumption issues through traffic traces and power measurements on LTE device over commercial LTE network. We analyzed the traces of various applications to understand the traffic characteristics. We also measured the power consumption of the various components of the device. This paper provides the cdf's of the packet size and packet inter-arrival times of background traffic of common applications (e.g., Skype, Google Talk, Twitter etc), and power consumption values and duration of low-power states which are crucial for the innovations and implementation of efficient power optimization mechanisms in LTE networks. View full abstract»

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    Design and Simulation of Random Access Procedure in TD-LTE

    Fa-Tang Chen ; Zheng Zhang
    Computational and Information Sciences (ICCIS), 2012 Fourth International Conference on

    DOI: 10.1109/ICCIS.2012.124
    Publication Year: 2012 , Page(s): 962 - 965
    Cited by:  Papers (2)

    IEEE Conference Publications

    To meet 3GPP, the latest release of LTE Release 9 Standard, this paper designs and simulates the random access procedure of Network side protocol stack in LTE system. Firstly, this paper introduces the initial events of the random access procedure, and describes contention and non-contention outlines based on the random access procedure. Then, we specifically describe contention based the random access procedure, and put forward several important problems' solutions. Based on the design, using Specification and Description Language (SDL), the simulation of the conformance requirement of specification is met, and the feasibility is validated by the simulation. View full abstract»

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    dMME: Virtualizing LTE mobility management

    Xueli An ; Pianese, F. ; Widjaja, I. ; Acer, U.G.
    Local Computer Networks (LCN), 2011 IEEE 36th Conference on

    DOI: 10.1109/LCN.2011.6115386
    Publication Year: 2011 , Page(s): 528 - 536

    IEEE Conference Publications

    With the convergence between phone and data networks in LTE and 4G, cellular signaling traffic is increasingly carried over IP. Control plane functions, once performed by dedicated machinery, are evolving into large-scale network applications with strict requirements on delay, availability, and processing throughput as mandated by 3GPP standards. In this paper we present DMME, a distributed architecture that implements mobility management for next-generation cellular systems. DMME is a scalable and cost-effective drop-in replacement for the LTE mobility management entity (MME). We evaluate the DMME scheme via analysis and simulation under several deployment scenarios, using mobility patterns drawn from synthetic models and from traces collected in a production network. We also report preliminary performance figures by our DMME prototype implementation. Our results confirm that distributed architectures are a viable choice to reliably support high-throughput, latency-sensitive control plane functions. View full abstract»

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    Secure handoff protocol in 3GPP LTE networks

    Bouabidi, I.E. ; Daly, I. ; Zarai, F.
    Communications and Networking (ComNet), 2012 Third International Conference on

    DOI: 10.1109/ComNet.2012.6217746
    Publication Year: 2012 , Page(s): 1 - 6
    Cited by:  Papers (1)

    IEEE Conference Publications

    To provide secure 3GPP LTE-WLAN interworking, Extensible Authentication Protocol-Authentication and Key Agreement (EAP-AKA) is used. However, EAP-AKA has several vulnerabilities such as disclosure of user identity, man-in-the-middle attack, Sequence Number (SQN) synchronization, and additional bandwidth consumption. Therefore, in this paper, we propose new re-authentication protocol for wireless 3GPP LTE. The proposed protocol guarantees stronger security, mutual authentication, and resistance against many attacks. The suggested solution proves its effectiveness following the studies of simulation which carried out according to different criteria handoff latency, loss and blocking rate. View full abstract»

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    Design of carrier-aggregated modulator for LTE-advanced

    Feng-Hsu Chung ; Jian-Yu Li ; Chun-Hsiang Chi ; Chang-Ming Lai ; Chia-Hao Tu ; Ping-Hsun Wu ; Yu-Ju Chuang
    Microwave Symposium (IMS), 2014 IEEE MTT-S International

    DOI: 10.1109/MWSYM.2014.6848657
    Publication Year: 2014 , Page(s): 1 - 3

    IEEE Conference Publications

    LTE-Advanced uses carrier aggregation (CA) of multiple component carriers (CCs) to achieve high-bandwidth transmission. To fulfill such technology, the novel carrier-aggregated modulator structure is proposed. In this work, the carrier-aggregated modulator is implemented in 0.18 μm CMOS technology and tested with two 10 MHz LTE-Advanced Release 10 signals to demonstrate the feasibility of the proposed architecture in both the intra-band and inter-band CA. The measured output spectrum and EVM meet the LTE-Advanced requirements. View full abstract»

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    Performance of dynamic CoMP cell selection in 3GPP LTE system level simulation

    Yuan Gao ; Yi Li ; HongYi Yu ; Shihai Gao
    Communication Software and Networks (ICCSN), 2011 IEEE 3rd International Conference on

    DOI: 10.1109/ICCSN.2011.6013577
    Publication Year: 2011 , Page(s): 210 - 213
    Cited by:  Papers (7)

    IEEE Conference Publications

    With the rapid progress of 3GPP LTE/LTE-A's standardization, research about coordinate multi point reception / transmission (CoMP) is very popular. However, topics about CoMP were freezed in around 2009 by 3GPP, so further research and performance analysis about key techniques in CoMP is very little. In this paper, we studied the dynamic cell selection method which is presented in some proposals, and a performance analysis in system level is performed using our LTE system level simulator. A better algorithm of Dynamic coordinated multi-point Cell Selection is studied and suggested according to the simulation result. View full abstract»

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    LTE and future evolutions for the benefits of security wireless networks

    Brouet, J. ; She Feng
    Wireless Mobile and Computing (CCWMC 2011), IET International Communication Conference on

    DOI: 10.1049/cp.2011.0927
    Publication Year: 2011 , Page(s): 447 - 454
    Cited by:  Papers (2)

    IET Conference Publications

    First responders make use of professional wireless system (e.g. TETRA) for conducting their missions. Those systems are today mainly used to convey voice and short messages. To improve the operational effectiveness, these organisations need wireless data transmission capabilities to exchange images, access to databases or transmit live video streams from the incident area. But, these needs cannot be realised with narrow-band technologies. However, LTE can bring these capabilities to first responders with timely exchange of files and transmission of live high definition video streams. Besides, future enhancements of LTE, LTE-Advanced, will further improve the performance not only to the benefits of mobile operators but also for first responders by providing additional coverage flexibility and more capacity especially at the cell edge, two key performance indicators of a radio security network. View full abstract»

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    Fuzzy logic based vertical handover algorithm between LTE and WLAN

    Aziz, A. ; Rizvi, S. ; Saad, N.M.
    Intelligent and Advanced Systems (ICIAS), 2010 International Conference on

    DOI: 10.1109/ICIAS.2010.5716261
    Publication Year: 2010 , Page(s): 1 - 4

    IEEE Conference Publications

    In the future there is a need to provide seamless mobility to the heterogeneous wireless network user while on the move. To achieve this there is a need to design an efficient vertical handover mechanism. User preference and system condition should be taken into consideration for efficient vertical handover. As the 3GPP Long-term evolution or LTE is the upcoming WWAN technology, performing an efficient vertical handover between LTE and next generation wireless LAN will be the challenge for future research. In this paper a fuzzy based vertical handover algorithm NG-VDA is proposed to provide an efficient vertical handover between LTE and WLAN to the user on the basis of multiple parameters. View full abstract»

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    A novel CQI-assisted sounding design for TDD LTE-Advanced system

    Baolong Zhou ; Lingge Jiang ; He Chen ; Shengjie Zhao
    Communications (ICC), 2012 IEEE International Conference on

    DOI: 10.1109/ICC.2012.6364280
    Publication Year: 2012 , Page(s): 4904 - 4908

    IEEE Conference Publications

    In the long term evolution (LTE) time division duplex (TDD) systems, base stations use uplink sounding reference signals (SRSs) to estimate downlink channel state information (CSI) for downlink beamforming transmissions. Because SRSs sent by up to 8 users are multiplexed on the same time-frequency resources, there exist mutual interferences among these SRSs over fading channels. Thus this scheme inevitably impacts the estimation accuracy of CSI and thereby degrades the beamforming performance. In this paper, we propose a novel sounding scheme to improve the quality of CSI, in which according to the CQIs (channel quality indications) periodically reported by each user and the bandwidth requirement of each user, BS dynamically schedules each user to send SRSs only on the requisite bandwidth with best CQIs instead of on full bandwidth or specified sub-bandwidth as in the current LTE TDD systems. Simulations show that the proposed scheme obtains much better estimation accuracy than the current scheme for various frequency-selective and/or time-selective fading channels, and is robust to frequency selective channels. Therefore the proposed scheme is applicable to the uplink SRS design in LTE-Advanced and other MIMO-OFDM TDD systems. View full abstract»

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    The research on the design of the RF front-end for the LTE - Advanced mobile terminals

    Fei Huang ; Jianyi Zhou ; Yingying Chu ; Zhiqiang Yu ; Weicheng Huang
    Microwave and Millimeter Wave Circuits and System Technology (MMWCST), 2013 International Workshop on

    DOI: 10.1109/MMWCST.2013.6814527
    Publication Year: 2013 , Page(s): 372 - 375

    IEEE Conference Publications

    LTE-Advanced technology is required to support 100MHz channel bandwidth and transfer rates in excess of 1Gbps. The 2.6GHz band is one of the core band of LTE-Advanced technology. This paper provide the detailed design of the RF front-end. The receiver uses the traditional double-conversion superheterodyne structure, while transmitter uses a zero-IF structure, able to obtain high receiver sensitivity and channel selectivity and small size. The tests' results show that the overall system performance is generally satisfactory. In the transmitter, the maximum output power is up to 23dBm and IMD3 is better than 45dB, for the 100MHz 16-QAM signal, the modulation accuracy is better than 4.18%; in the receiver, the gain flatness is less than 2.66dB, for the 5MHz 16-QAM modulated signals within the passband, the modulation accuracy is better than 1.34%. The transceiver switch time is less than 1.72μs. View full abstract»

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    Relay approaches in the LTE Advanced network

    Karpovych, O.B. ; Ishchenko, M.V. ; Shelkovnikov, B.N.
    Microwave and Telecommunication Technology (CriMiCo), 2012 22nd International Crimean Conference

    Publication Year: 2012 , Page(s): 277 - 278

    IEEE Conference Publications

    Relaying is one of the proposed technologies for 3GPP LTE-Advanced networks, one of the main tasks of which is an increase of network capacity and the expansion of its coverage area. A method of dynamic relay in LTE Advanced networks was introduced. That method still maintains compatibility with the user's equipment LTE Release 8, and does not limit the flexibility and reliability expected from the relay. View full abstract»

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    On the Tail-Biting Convolutional Code Decoder for the LTE and LTE-A standards'

    Omar, M.H. ; El-Mahmoudy, A. ; Seddik, K.G. ; Elezabi, A.
    Signals, Systems and Computers, 2013 Asilomar Conference on

    DOI: 10.1109/ACSSC.2013.6810330
    Publication Year: 2013 , Page(s): 510 - 514

    IEEE Conference Publications

    In this paper, we consider the design of the Tail-Biting Convolutional Code Decoder (TB-CCD) for the Long Term Evolution (LTE) system. Tail-biting convolutional coding is used for channel coding on two downlink channels, namely the Physical Broadcast Channel (PBCH) and the Physical Downlink Control Channel (PDCCH). The decoding in the latter channel occurs blindly, with the decoder having no prior knowledge of the location of the desired bits. The crucial constraint on the TB-CCD design will be the required decoding time and the exhaustive processing for the PDCCH blind decoding. The TB-CCD will be required to carry out at most 44 decoding attempts per LTE subframe, which has a duration of 1 ms. In this paper, we describe the various aspects of our design that result in savings in processing time and complexity while showing negligible performance degradation. We then provide a description of the implementation architecture for the selected TB-CCD design and briefly describe the verification process. View full abstract»

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    Self-optimization of Random Access Channel in 3GPP LTE

    Yilmaz, O. ; Hamalainen, J. ; Hamalainen, S.
    Wireless Communications and Mobile Computing Conference (IWCMC), 2011 7th International

    DOI: 10.1109/IWCMC.2011.5982742
    Publication Year: 2011 , Page(s): 1397 - 1401

    IEEE Conference Publications

    In this paper, a mathematical framework for the Random Access Channel (RACH) modeling in Long-Term Evaluation (LTE) technology is presented on the basis of probability theory and statistics. The framework is exemplified by basic investigations on the self-optimization of RACH resource unit allocation and preamble split. Evaluations are performed by modeling a stochastic process in which outputs of a dynamic LTE network simulator are taken as inputs. View full abstract»

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    LTE system scheduling algorithm based on utility function

    Tian Xie ; Xiaowei Hui
    Communication Software and Networks (ICCSN), 2011 IEEE 3rd International Conference on

    DOI: 10.1109/ICCSN.2011.6014743
    Publication Year: 2011 , Page(s): 370 - 373

    IEEE Conference Publications

    LTE system performance largely depends on the high efficiency of frequency domain resource scheduling. This paper presents a single-cell LTE Downlink scheduling model, and then introduces the economic concept of utility function in order to design a LTE system scheduling algorithm based on the utility function (UBS) and we simulate the algorithm. We simulate and compare throughput, fairness, packet loss, packet delay and other aspects of the algorithm and the classical scheduling algorithm. The simulation results shows that the UBS algorithm have better system performance and utility value. View full abstract»

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    Adaptive Multi-Tx Multi-Rx MIMO Transmission Scheme for LTE-Advanced Downlink

    Xiaolin Hou ; Zhan Zhang ; Kayama, H.
    Global Telecommunications Conference, 2009. GLOBECOM 2009. IEEE

    DOI: 10.1109/GLOCOM.2009.5425859
    Publication Year: 2009 , Page(s): 1 - 7
    Cited by:  Papers (2)

    IEEE Conference Publications

    Multiple-input multiple-output (MIMO) spatial multiplexing has been adopted by 3GPP long term evolution (LTE) to increase the peak spectrum efficiency. However, it will lose its effectiveness for cell edge users due to the inter-cell interference (ICI). Therefore, 3GPP LTE-Advanced (LTE-A) is considering to introduce some multi-cell cooperative transmission techniques to solve this problem. In this paper, we first propose the distributed multi-Tx multi-Rx (MTMR) MIMO spatial multiplexing for LTEA downlink, which only needs partial cooperation, so the heavy backhauling overhead and the high implementation complexity encountered in the traditional full cooperation scheme can be avoided. Meanwhile, because of the efficient utilization of multicell transmit power and spatial degree of freedom, a higher spectrum efficiency can be achieved by MTMR MIMO spatial multiplexing in good channel conditions compared with the other partial cooperation schemes. Then in order to ensure the highest possible cell edge spectrum efficiency to be achieved in different channel conditions, we further integrate multiple distributed cooperation modes into the same framework and introduce a mechanism of adaptive cooperation mode selection. Both qualitative analysis and quantitative simulations show the proposal's effectiveness and indicate it a promising candidate for the cooperative transmission in LTE-A downlink. View full abstract»

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    Robust Synchronization for 3GPP LTE System

    Xu, W. ; Manolakis, K.
    Global Telecommunications Conference (GLOBECOM 2010), 2010 IEEE

    DOI: 10.1109/GLOCOM.2010.5684054
    Publication Year: 2010 , Page(s): 1 - 5
    Cited by:  Papers (14)

    IEEE Conference Publications

    This paper addresses problems related to time and frequency synchronization as well as blind CP (cyclic prefix) type identification in 3GPP LTE system. We start with a general framework based on maximum likelihood (ML) parameter estimation. Then, simplified practical algorithms for estimating time and frequency offset as well as blind CP length are described. Finally, a robust hierarchical scheme is proposed. Specifically, the CP based lagged auto-correlation is first employed to identify the CP type, estimate the carrier frequency offset (CFO), and grossly determine the symbol timing, and then the pilot (i.e. the LTE primary synchronization signal) based cross-correlation is used to more accurately determine the symbol and frame timing. A solution is given to the problem with unequal-length symbols, such as the symbols with the normal CP specified in the LTE. The proposed hierarchical scheme has both low complexity and high accuracy and can be realized without hardware support. View full abstract»

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    UL Performance of Type-1 Relay Enhanced FDD LTE-A Networks with Unaligned Backhaul Subframes

    Wei Hong ; Jing Han ; Haiming Wang
    Vehicular Technology Conference (VTC Spring), 2011 IEEE 73rd

    DOI: 10.1109/VETECS.2011.5956205
    Publication Year: 2011 , Page(s): 1 - 5

    IEEE Conference Publications

    Long Term Evolution-Advanced (LTE-A) networks are termed as the 4G cellular systems and the standardization has been included in 3GPP Release 10. There are several new techniques used in LTE-A systems to fulfill the target of 4G requirements such as Relay Node (RN), Carrier Aggregation (CA) and so on. Relay has been taken as a promising key technique in the LTE-A network to meet its demanding requirements which could enhance the coverage and increase the data rates in a cost efficient manner. In 3GPP Release 10, Type-1 relay was mainly investigated, which works in half-duplex way and in in-band mode. So the backhaul link and access link operate at the same band, while they are time multiplexed. If there are multiple relays in each cell, the backhaul sub-frames allocated for backhaul link can be the same or different in different relays. In this paper, the uplink performance of the relays with different backhaul sub-frames in FDD LTE-A system is evaluated by the system-level simulator. Some suggestions for the relay deployment are also recommended. View full abstract»

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    Power efficient uplink LTE with CPM-SC-IFDMA

    Rahman, R. ; Perrins, E. ; Green, M.
    MILITARY COMMUNICATIONS CONFERENCE, 2011 - MILCOM 2011

    DOI: 10.1109/MILCOM.2011.6127721
    Publication Year: 2011 , Page(s): 507 - 512

    IEEE Conference Publications

    Power efficiency represents a key concern in the mobile communication field. Poor power efficiency leads to shorter battery life and increases the cost of the mobile device. Improving power efficiency is more important for uplink transmission since in uplink the transmitter is placed in the battery-powered mobile device which has limited power resources. In this paper we propose a power efficient scheme, CPM-SC-IFDMA, for uplink transmission in LTE (Long Term Evolution). The proposed scheme, CPM-SC-IFDMA, combines the key advantages of CPM (continuous phase modulation) with SC-IFDMA (Single Carrier Frequency Division Multiple Access with Interleaved subcarrier mapping) in order to increase the power amplifier efficiency of the transmitter. In this work, we investigate the bit error rate (BER) performance of the proposed scheme in LTE specified channels. The BER performance of the CPM-SC-IFDMA scheme is compared with that of a LTE specified transmission scheme, QPSK-LFDMA (QPSK modulated SC-FDMA with localized subcarrier mapping), combined with convolutional coding (CC-QPSK-LFDMA). We first show that CPM-SC-IFDMA has a much higher power efficiency than CC-QPSK-LFDMA by simulating the PAPR (peak-to-average-power-ratio) plots. Then, using the data from the PAPR plots and the conventional BER plots (BER as a function of signal-to-noise-ratio), we show that, when compensated for power efficiency loss CPM-SC-IFDMA has a superior performance relative to CC-QPSK-LFDMA by up to 3.8 dB in the LTE specified channels. View full abstract»

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    Automotive grade MIMO antenna setup and performance evaluation for LTE-communications

    Thiel, A. ; Ekiz, L. ; Klemp, O. ; Schultz, M.
    Antenna Technology (iWAT), 2013 International Workshop on

    DOI: 10.1109/IWAT.2013.6518325
    Publication Year: 2013 , Page(s): 171 - 174
    Cited by:  Papers (4)

    IEEE Conference Publications

    Multiple-input-multiple-output (MIMO) is a technique to achieve high data rates in mobile communication networks and is used by the Long-Term Evolution (LTE) standard. The integration of a two antenna MIMO system for usage in worldwide LTE networks into a conventional automotive roof top antenna is discussed. In-situ antenna measurement results of the final LTE MIMO configuration are shown. Furthermore initial test results of the integrated LTE antenna system in an 800 MHz live network are presented and a comparison to a reference system consisting of two quarter-wavelength monopole antennas with ideal spatial separation is provided. View full abstract»

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    Efficient QR decomposition algorithm for LTE standard

    Kalyani, K. ; Sellathambi, D. ; Rajaram, S.
    Computing, Communications and Networking Technologies (ICCCNT),2013 Fourth International Conference on

    DOI: 10.1109/ICCCNT.2013.6726492
    Publication Year: 2013 , Page(s): 1 - 5

    IEEE Conference Publications

    LTE has become a hotspot of research and application in high speed broadband wireless access. MIMO signal detecting algorithms are necessary process in LTE receiver design. One of the main baseband function in MIMO receivers is QR decomposition of the channel matrix. This paper presents a new QR decomposition algorithm with several advantages to the previous method. The execution time of the QRD algorithm reduced by designing a new algorithm based on Householder transformation (HT) instead of existing algorithm. For QRD of large size matrices, this algorithm can achieve computational efficiency with robust numerical stability. The proposed scheme reduces the computation by half the amount to previous method. View full abstract»

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    SFBC design tradeoffs for mobile SC-FDMA with application to LTE-advanced

    Narasimhan, B. ; Al-Dhahir, N. ; Minn, H.
    Acoustics Speech and Signal Processing (ICASSP), 2010 IEEE International Conference on

    DOI: 10.1109/ICASSP.2010.5495971
    Publication Year: 2010 , Page(s): 3458 - 3461
    Cited by:  Papers (1)

    IEEE Conference Publications

    Single-carrier frequency-division multiple-access (SC-FDMA) has been adopted in the uplink of the LTE standard due to its lower peak-to-average-power ratio (PAPR) compared to orthogonal frequency-division multiple access (OFDMA). Recent activities in the LTE-advanced (LTE-A) standardization have focused on effective uplink transmit diversity schemes with low PAPR but without considering the performance degradation due to Doppler despite the fact that LTE-A is required to support high mobility. In this paper, we present an open-loop space-frequency block coding (SFBC) scheme for the SC-FDMA uplink and demonstrate its robustness to high Doppler and large multipath delay spread while enjoying full spatial diversity, low PAPR and practical decoding complexity by a suitable design of the frequency span of each SFBC codeword. In this paper, we study the design tradeoffs involved in SFBC design for mobile SC-FDMA. View full abstract»

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    NextGen wireless access gateway analysis of combining WiMAX and LTE gateway functions

    Keshava Murthy, K.S.
    Internet Multimedia Services Architecture and Applications, 2008. IMSAA 2008. 2nd International Conference on

    DOI: 10.1109/IMSAA.2008.4753911
    Publication Year: 2008 , Page(s): 1 - 6
    Cited by:  Papers (2)

    IEEE Conference Publications

    The capabilities of the wireless networks are continuously being enhanced to meet ever growing demand of the higher data rates for accessing wide range of Internet services in the mobile node. The IEEE 802.16e mobile worldwide interoperability for Microwave Access (WiMAX), 3GPP long term evolution (LTE) and 3GPP2 ultra mobile broadband (UMB) wireless technologies are identified as next generation technologies beyond 3G to meet this growing demand. All these technologies are using orthogonal frequency division multiple access (OFDMA) as the radio access technology to achieve higher data rates, efficient spectrum usage, higher cell throughput, seamless mobility and all-IP based core network for distributed, scalable network architecture to support wide range of applications/services with better quality of experience. Some of BS Original Equipment Manufacturers (OEM) already support both LTE and WiMAX base station function on the same hardware platform with different software loads. Looking at this trend, and considering the user plane transport similarities in ldquobeyond 3Grdquo networks, this paper analyses the possibility of having common access gateway functional modules for supporting LTE networks mobility management entity (MME), serving gateway (S-GW) functions and WiMAX networks access services network gateway (ASN-GW) functions. View full abstract»

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