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3G Mobile Communication Technologies, 2002. Third International Conference on (Conf. Publ. No. 489)

Date 8-10 May 2002

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Displaying Results 1 - 25 of 112
  • Downlink soft handover gain in UMTS networks under different power control conditions

    Page(s): 47 - 51
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (423 KB)  

    The downlink soft handover gain is analysed in UMTS networks under three different power control situations: without power control, with perfect power control and with imperfect power control. The results show that although power control in the downlink direction is not as crucial as it in the uplink direction, it does have a significant influence on the downlink soft handover gain. The downlink soft handover gain will be overestimated without considering the power control and underestimated without considering the imperfection of the power control process. View full abstract»

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  • Theory and practice in 3G network planning

    Page(s): 74 - 80
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (951 KB)  

    This paper discusses 3G network planning in a 3G network environment, and compares this to network planning for GSM. An overview of 3G network planning is then given. Network optimisation is discussed with a specific example of some work carried out on soft handover processing in a real network environment. View full abstract»

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  • Measurement-based optimisation of in-building coverage for UMTS

    Page(s): 221 - 224
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (631 KB)  

    Using measurements, a method for optimising in-building UMTS coverage is proposed, minimising cost, complexity and development time. This approach also increases reliability, capacity and system performance for UMTS networks, where interference management is the key to success in improving coverage and capacity. View full abstract»

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  • Enabling network redundancy in the radio access network

    Page(s): 27 - 31
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    In the current UTRAN (UMTS terrestrial radio access network) architecture, redundancy is one of the major issues, usually provided by means of robust network elements with high reliability and protection switching in the transport network. When the radio access network evolves to a more distributed architecture, the functions of the RNC (radio network controller) are split according to control and user plane and functional scope (cell, user, multi-cell). In such a way, the network topology becomes more complex, and the contribution of the transmission network becomes a much more important part of the network reliability. A certain availability of single nodes is still needed, which may require also the application of node redundancy mechanisms. In such an access network, there are certain nodes that are location-independent, of a distributed (nonhierarchical) topology and with less stringent delay requirements. For these types of new nodes, network redundancy and the pooling of server nodes promises to be a good alternative to provide reliability in the radio access network. View full abstract»

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  • Predictive power control for S-UMTS based on least-mean-square algorithm

    Page(s): 128 - 132
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (533 KB)  

    In order to exploit the presence of non-zero autocorrelation between consecutive samples of channel variations, predictive schemes based on a recursive least squares (RLS) adaptive algorithm have been proposed. The main motivation for using RLS is its fast convergence property. The RLS algorithm places enormous computational burden on the transmit power control system. In slow power control, however, the fast convergence property is not a stringent requirement. Therefore, we propose a predictive power control scheme based on a least-mean-square (LMS) algorithm. Unlike the RLS algorithm, the LMS algorithm is simple to implement and has low computational complexity. Furthermore, the LMS algorithm has better tracking properties than the RLS algorithm in a nonstationary environment. We demonstrate, through simulation, that a performance gain of up to 0.5 dB in terms of the standard deviation of transmit power control error, over the conventional closed-loop transmit power control, can be achieved through the use of the LMS algorithm. Furthermore, we optimise the performance of the closed-loop power control based on parameters of the LMS predictor, namely adaptation constant and predictor order. View full abstract»

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  • IP based services at the UMTS radio interface

    Page(s): 32 - 36
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    The Universal Mobile Telecommunications System (UMTS) as a 3rd generation mobile telecommunications system is designed to provide mobile Internet access to the user. E-mail and World Wide Web (WWW) browsing sessions as mobile data service applications are examined for performance analysis by simulation. A WWW traffic model is presented as the basis of a WWW load generator. The paper presents this traffic load generator integrated into an event driven, bit accurate UMTS radio interface simulator (URIS). The simulator is based on a detailed implementation of the standardized UMTS protocol stack extended by the Transmission Control Protocol (TCP) and the Internet Protocol (IP). Simulation results of quality of service parameters like delay and throughput depict the performance of mobile Internet access over UMTS. View full abstract»

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  • Performance improvement for real-time video communications by link adaptation in E-GPRS networks

    Page(s): 489 - 494
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (557 KB)  

    The provision of video communications over wireless links is a challenging task due to the poor performance of video compression algorithms in time-varying error-prone environments. The paper presents a performance enhancement method for real-time video communications by employing link adaptation in enhanced general packet radio service (E-GPRS) cellular networks. A novel link adaptation algorithm, which is based on physical layer measurable quantities, including block error rate (BLER), received signal strength (RSS) and the gradient of RSS, is proposed and analysed. The effects of a link adaptation scheme at video frame level on improving video quality with variable source rate by varying the channel-coding scheme for a fixed channel allocation is studied. The algorithm is tested for MPEG-4 coded video transmissions over simulated channel conditions based on the GSM mobile radio multipath propagation models (see 3GPP TS 05.05, 1999). The performance obtained using the proposed method is compared to a non-adaptive case and to the ideal adaptive case, where the choice of channel coding scheme is made based on the carrier-to-interference ratio (CIR) of the transmission channel. View full abstract»

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  • Performance of antenna hopping techniques for packet radio transmission

    Page(s): 525 - 528
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (425 KB)  

    A transmission diversity scheme based upon antenna hopping is investigated for packet radio transmission for a typical urban environment. Our simulation results reveal that the gain obtained with antenna hopping at high speed is not significant. However, considerable gain is observed for low code rates such as CSI in GPRS, and MCS 5 and MCS 6 in EGPRS. View full abstract»

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  • Multicasting in UMTS

    Page(s): 96 - 101
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (598 KB)  

    Future third generation wireless network operators, such as those holding UMTS (Universal Mobile Telecommunications System) licenses will be able to deliver higher bandwidth content rich services over new infrastructure to end-users of innovative new terminal equipment. In order to reduce the risk of potential network overload, it is envisaged that in future, multimedia of mass interest will be multicast simultaneously to multiple users in the network. Applications such as those becoming more widely deployed on the Internet, (video/audio streaming) will provide the revenue pull to compel UMTS operators to consider re-using them in their networks. The Internet Engineering Task Force, (IETF) has accounted for these traffic requirements by introducing optional protocols that would avoid the replication of packets so that applications could be transported in a more cost effective way, (IP Multicast). In order to allow similar one-to-many services to be used in UMTS, the Third Generation Partnership Project, (3GPP) has begun optimising the future global standards for UMTS. In future UMTS networks, high bit rate services could be transported over bearers in a more resource efficient manner, (broadcast/multicast applications) addressing the issues that are unique to wide area wireless environment. This paper provides an overview of the potential architectural design challenges that would allow more efficient distribution of unidirectional point-to-multipoint multimedia to multiple subscribers, whilst conserving network resources both in the core-network and the radio access network. View full abstract»

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  • Application of load control in 3G CDMA networks for improved system level modelling and performance analysis

    Page(s): 297 - 301
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (591 KB)  

    In this paper we developed a system level model of a CDMA network based on the power control ability of the system. From the load control problem formulation a measure of the system performance in terms of the system outage probability was derived, which is based on the system load and the resource consumption of each service. By means of dynamic system simulations we also showed how well the system level model fits with the numerical results. The presented system level model can be used for efficient network wide studies. For example, the end-to-end performance of the overall system may be evaluated without going into a deep level of detail for the CDMA network. Moreover, accurate models of the system behaviour can be used to enhance the decision criteria for the inherent load control methods, like call admission control. View full abstract»

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  • Standardised service capabilities: the need for standardisation illustrated by the development of the presence service

    Page(s): 360 - 365
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    It has been frequently stated that services will no longer be standardised but it is the service capabilities available as tool kits for developers that will be standardised. Such tool kits provide the foundation upon which numerous services can be deployed to serve the end user. Despite this, industry bodies such as the 3rd Generation Project Partnership (3GPP) still standardise complete services such as the multimedia messaging service. The rationale for this latter approach should be questioned and the reasons why the toolkit approach has not been more widely adopted analysed. In a 3G wireless environment, the provision of services could be provided by different players and is not reserved to the traditional telecommunications service providers. It is therefore essential to reach an agreement between the operators that run the networks, the manufacturers that provide telecommunications equipment and application developers to ensure interoperability. Clearly it is desirable to reuse as much work that as been done in bodies such as the Internet Engineering Task Force (IETF). This paper provides a case study on the presence service, a capability that is currently being standardised in 3GPP, to identify a successful approach to toolkit standardisation and the development of a broad range of support across different players in the industry. View full abstract»

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  • Transport solutions for 3G cellular radio access network

    Page(s): 292 - 296
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (510 KB)  

    Although the planning, design, acquisition, and deployment of radio base station sites are seen as the major challenges in the roll out of 3G networks, the associated provision and optimisation of transport capacity to link these sites to the controller and switching sites presents its own problems to network operators. This paper examines the requirements and standards for transport within the 3GPP Release 99 Asynchronous Transfer Mode (ATM) based UMTS Terrestrial Radio Access Network (UTRAN), and presents a number of solution architectures that address these requirements. View full abstract»

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  • Intelligent cellular coverage control according to geographic call traffic distribution

    Page(s): 423 - 427
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (603 KB)  

    We investigate a smart antenna based load balancing scheme, which dynamically changes cell size and shapes according to the geographic call traffic distribution over time. The performance of the whole cellular network can be improved by contracting the antenna pattern around the source of peak traffic and expanding adjacent cells coverage to fill in the coverage loss. Our previous work based on scenarios with nonuniformly distributed traffic scenarios has shown the improvement of system capacity of such a dynamical cellular coverage planning scheme exceeds 20%. A negotiation approach for the real-time control of cellular network coverage is described. View full abstract»

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  • Radio planning of third generation networks in urban areas

    Page(s): 64 - 68
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (550 KB)  

    We examine some of the key issues facing radio network design engineers as they set about planning third generation networks in urban areas. 3G networks have one major difference compared with their second generation (2G) predecessors; they are designed to support data rates of up to 2 Mbit/s, and hence a much wider range of services. It also means that the task of designing and planning 3G networks become far more demanding because of the wide variation in the type and mix of traffic offered. We show the importance of having good models for traffic and user distribution in radio network planning and we also discuss the requirements of 3G planning tools. We highlight some of the challenges associated with using multi-tier cellular structures (e.g., macrocells and microcells) and discuss some of the factors that influence design decisions. At present, most of the focus of 3G network operators is on network rollout. However, if 3G becomes the hoped for runaway success, then the problems of designing high capacity, high quality urban networks are likely to present themselves sooner rather than later. Therefore, these issues need to be considered now. View full abstract»

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  • An efficient algorithm for distributed power control in cellular radio systems

    Page(s): 123 - 127
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (502 KB)  

    In most modern cellular radio systems, efficient interference management aims at acceptable carrier-to-interference (CIR) ratios in all active communication links in the system. Power control is an integral technique in the design and operation of such cellular radio systems. It can be used to reduce cochannel interference and hence the near-far effects. Two main approaches have been adopted for power control, which are known as centralized and distributed. Centralised power control requires knowledge of the information of all link gains between base stations and mobiles, which is very difficult to implement for large real-time systems. We consider distributed power control algorithms, which are based only on local information at the base station. A new technique, based on the method of projection onto convex sets (POCS), is developed and is used to obtain the minimum protection ratio. Simulation results show that the POCS method achieves much faster convergence and improved outage probability than other conventional methods. View full abstract»

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  • Applications of speech quality measurement for 3G

    Page(s): 250 - 255
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (554 KB)  

    The speech quality delivered by a 3G network is determined by many factors, including speech and channel coding, the design of the device, and signal processing algorithms and their interactions. This paper examines the key speech quality issues in 3G networks, describes the basics of objective speech quality measurement, and highlights its application in 3G planning, procurement, optimisation and network monitoring. View full abstract»

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  • Blind adaptive single user detection with adjustable step size for DS/CDMA communication over a Rayleigh fading mobile channel

    Page(s): 180 - 184
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (530 KB)  

    An adaptive single user algorithm with adjustable step size has been proposed for use in DS/CDMA based communications. In addition, the adaptive step size algorithm has been incorporated into two multipath combiners in the forms of the RAKE receiver and the general sidelobe canceller architecture for use in a Rayleigh fading channel. The frame error rate results obtained by means of computer simulation illustrate the superior multiple access interference resistance of the proposed detectors compared to the conventional RAKE receiver. Furthermore, the results also reflect the enhanced convergence speed of the detectors and their ability to adjust the step sizes according to the rate of change of the received signal. Joint blind detection and blind channel parameter estimation and the robustness of the gradient adaptive step size constant modulus algorithm to imperfect channel estimation are the topics of future study by the authors. View full abstract»

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  • Redefining user input on handheld devices

    Page(s): 388 - 393
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (662 KB)  

    In migrating users to 3G applications, developers, device manufacturers and network operators are asking the public to believe in the wireless Internet. While improvements have been made in many areas, we believe that the user input methods are a remaining inhibitor. Devices have continued to get smaller, while at the same time require more functionality. We present a technology called the Fastap keypad with a 3D arrangement of keys where two keyboards have effectively been superimposed on top of each other to form keys that are each close to the size of desktop keyboard keys. More than fifty keys can be placed on the front of a handheld device the size of a phone. The 3G applications that are envisioned currently use 12 keys for data entry of letters, numbers and punctuation characters. Applications requiring data input will all benefit from an arrangement of full sized "1 key per character" keys that can be used with much less learning and key actuations than current methods. We believe that many applications will not make a smooth transition to wireless without an improved data entry method. Fastap technology provides an option for user input that is not available today on devices. It provides ease of use, large keys, versatile implementation methods, and simple manufacturing. By combining these features in one place, users can access applications more quickly, with fewer keystrokes, and without accessories. View full abstract»

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  • Accuracy and hearability of mobile positioning in GSM and CDMA networks

    Page(s): 350 - 354
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (504 KB)  

    We investigate the problems encountered in mobile position locating (PL) in cellular networks. The two main problems are the inaccuracy of the estimated position and the hearability of the PL terminal, i.e., the ability to receive sufficient signals from at least 3 base stations (BS) to estimate its position. Our work is based on the downlink time difference of arrival (TDOA) positioning technique proposed for the LoCating Services (LCS) in GSM and wideband CDMA. We also study the effect of the non-line-of-sight (NLOS) link between the BS and mobile terminal (MT) on the accuracy of the estimated position. The idle period downlink (IPDL) scheme, proposed for the WCDMA network to mitigate the inaccuracy and hearability problems caused by interferences from other 'active' users or BS, is also addressed. View full abstract»

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  • Dynamic spectrum allocation in hybrid networks with imperfect load prediction

    Page(s): 444 - 448
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (663 KB)  

    The paper presents an investigation into the effects of imperfect load prediction on the performance of a dynamic spectrum allocation (DSA) scheme. Previous work has assessed the performance of DSA, but this has assumed that the DSA could make an accurate prediction of the future loads on networks sharing the spectrum. The paper investigates the performance of nine different load prediction schemes in adapting to seven different traffic scenarios. The results show how the performance of DSA can be improved with time-series prediction schemes combined with load histories, under unexpected traffic scenarios. In addition, the paper investigates when the prediction should be based on a time-series prediction algorithm or on a load history, and also the effect of the time interval between spectrum reallocations on the load prediction. View full abstract»

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  • An architecture for a distributed 3G mobile terminal

    Page(s): 459 - 463
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (667 KB)  

    The paper develops an abstract architectural view of a distributed mobile terminal for use in third generation mobile systems, including UMTS and the Mobile Internet. The actual physical form of a third generation terminal is still debatable; however, it is possible to derive an architectural prescription for the logical form such a terminal should take. The paper starts by reviewing the current status of mobile terminal development and an analysis of the perception of what comprises a third generation mobile terminal. From this analysis, hints as to what elements that comprise the architecture are extrapolated. Building upon these findings, the paper presents, for discussion, a conceptual architecture for a 3G mobile terminal, which imposes no restrictions upon implementation. The general operation of the functions that comprise the architecture are outlined. View full abstract»

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  • On signalling issues for the high speed downlink packet access in UMTS

    Page(s): 137 - 140
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (471 KB)  

    The high-speed downlink packet access (HSDPA) adopted in UMTS aims to support, integrated on the same carrier, voice on the dedicated channel (DCH) and high-speed data on the high-speed downlink shared channel (HS-DSCH). Taking account of some noticeable deficiencies in the system, the paper examines different signalling approaches for the HSDPA, based on a two-step signalling scheme. In this scheme, the downlink signalling control information associated with the HS-DSCH is carried by shared control channels (SCCH-HS). A high-speed indicator (HI) is provided by the dedicated physical channel (DPCH). We analyse the impact of using the uncoded HI on the power consumption and overall efficiency of the system. Based on that, we propose some channel coding schemes for protecting the HI and improving the deficiencies. In particular, we recommend a very similar code to the previous one for encoding the information of the transport format combination indicator (TFCI). This new coding scheme can provide protection for the HI with high error-control capacity and have good error performance for both Gaussian and fading channels. View full abstract»

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  • The effect of electrical and mechanical antenna down-tilting in UMTS networks

    Page(s): 86 - 90
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (607 KB)  

    In an interference-limited CDMA system, network planning and the optimal installation of infrastructure components are important issues. This is not only to increase system capacity but also to allow for a smooth network operation. Whereas the Node B locations can hardly be changed, modern antennas provide adaptation mechanisms with which the antenna down-tilt angle can be adapted to the various needs of the network. This is dependent on the locations of the base station sites, the resulting cell sizes, and the current traffic situations. The simulations presented in this paper show basic effects on network coverage and capacity due to changes in the antenna down-tilt angle configuration. It is differed between mechanical and electrical adjustment of the down-tilt resulting in slightly different antenna characteristics. View full abstract»

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  • WCDMA radio network planning for location services and system capacity

    Page(s): 340 - 344
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1222 KB)  

    The majority of radio network planning processes being developed for WCDMA focus upon providing adequate coverage and capacity performance. These processes generally include the requirement to tune the CPICH physical channel such that sufficient power is assigned to provide coverage without assigning excessive power that would result in less power being available to user traffic. This paper studies the performance of OTDOA based location services when the radio network has been planned without explicitly accounting for the requirement to receive at least three CPICH signals at each location. The paper continues by studying the impact upon both system capacity and OTDOA performance when the power assigned to the CPICH channel is increased. View full abstract»

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  • Novel prioritised EGPRS medium access regime for reduced file transfer delay during congested periods

    Page(s): 550 - 554
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (610 KB)  

    The goal of this paper is to investigate the efficiency of different algorithms used for resource allocation in data transfer over EGPRS networks. The focus is on the efficiency during congested periods in order to ensure reduced file transfer delay. A number of algorithms are presented for the resource allocation, and some generic mathematical results are presented for a two coding system. Simulation is relied on to produce results for the algorithms and it is found that iterative round robin (IRR) and oldest queue (OQ) produce the best results. These are then proposed to be good candidates for implementing transmission control. View full abstract»

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