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Wireless Personal Multimedia Communications (WPMC), 2012 15th International Symposium on

Date 24-27 Sept. 2012

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Displaying Results 1 - 25 of 144
  • [Front cover]

    Page(s): 1
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    Freely Available from IEEE
  • [Front matter]

    Page(s): 1 - 40
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    Freely Available from IEEE
  • Table of contents

    Page(s): 36 - 68
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    Freely Available from IEEE
  • A cross-layer design for video applications based on QoE prediction

    Page(s): 534 - 538
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (314 KB) |  | HTML iconHTML  

    In this paper, we propose a cross-layer design scheme for optimizing resource allocation of video applications based on Quality of Experience (QoE) prediction. A novel mapping model between Peak Signal-to-Noise Ratio (PSNR) and Mean Opinion Score (MOS) based on hyperbolic tangent function is presented to reflect the relation between objective parameters and subjective perceived quality. On the basis of this model, we propose a QoE prediction function and utilize the Particle Swarm Optimization (PSO) method to solve the resource allocation problem. Simulation results show that our QoE-based cross-layer design scheme leads to significant improvements in terms of maximizing user-perceived quality as well as maintaining fairness among users. View full abstract»

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  • A dynamic channel switching mechanism based on vehicle density

    Page(s): 212 - 216
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB) |  | HTML iconHTML  

    The Wireless Access in Vehicular Environment (WAVE) protocol should be widely used in vehicle-to-infrastructure and vehicle-to-vehicle radio communications. In the traditional mechanism, channel switching method cannot self-adjust the time point of channel switching flexibly according to the density of the vehicles, causing the problem of driving safety and channel usage efficiency over Control Channel (CCH). In this paper, we propose an adaptively dynamic channel switching mechanism based on vehicle density to overcome above problems. Furthermore, we introduce a practical road scenario model and carry out a series of rigorous simulations based on NS3 simulator. Numerous simulation results have witnessed an improvement in successful ratio of sending beacon message as well as Service Channel (SCH) throughput. View full abstract»

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  • A joint source-channel decoder for H.264 SPS and PPS headers

    Page(s): 443 - 447
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (755 KB) |  | HTML iconHTML  

    This paper proposes a joint source-channel decoder (JSCD) to decode the Sequence Parameter Set (SPS) and Picture Parameter Set (PPS) headers for the H.264 encoded video sequence. Erroneously received headers can render the entire video sequence un-decodable. By exploiting the syntax and semantics of the headers as well as certain a priori information, our proposed JSCD is capable of reducing the probability of erroneous headers and hence improving the overall PSNR of the video by as high as 3 dB. View full abstract»

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  • A listening power-saving Mechanism in MAC layer for the DCF of 802.11n

    Page(s): 529 - 533
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (324 KB) |  | HTML iconHTML  

    In this article, we propose a listening power-saving Mechanism (LPSM) which consists of an intelligent scheme for intelligent idle listening [16], a Network Allocation Vector (NAV) scheme to reduce the energy consumed in listening to the transmissions from other active stations, and a sleeping technique for an idle station to reduce the energy consumed in idle listening regardless of whether the station is busy or not. Our analysis and simulation results show that our schemes can reduce the total power consumption of a busy station by about 80% through shortening the time in listening to the idle channel and to the transmission of other busy stations effectively. In particular, energy consumption is significantly reduced when the number of active stations is very large. The power consumption for an idle station applying the sleeping technique in Listening Power-Saving Mechanism (LPSM) can be reduced by 33.7% if the maximal beacon interval is set to 320ms. An important characteristic of our scheme is that it is fully compatible with the legacy Distributed Coordination Function (DCF) and that there will be no throughput reduction if this power saving mechanism is applied to the DCF of 802.11. View full abstract»

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  • A model for evaluating QoE of mobile Internet services

    Page(s): 438 - 442
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (334 KB) |  | HTML iconHTML  

    In recent years, with the increasingly intense competition in mobile Internet services, both network operators and application developers pay more and more attention to Quality of Experience (QoE). However, there is no universal QoE evaluation model and method for mobile Internet services. In this paper, we propose a universal QoE model and evaluation method for mobile Internet services from a mobile application perspective. The QoE value obtained through our model is the overall subjective feelings of end-users for a mobile application in specific network, instead of simple “Excellent” or “Good”. View full abstract»

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  • A multi-mode space-time coded MIMO system using lattice-reduction aided detection

    Page(s): 399 - 403
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB) |  | HTML iconHTML  

    This paper presents a multi-mode space-time coded MIMO system with the assistance of lattice-reduction-aided MIMO detection. The proposed system switches among a number of pre-designed signaling modes, which include the spatial multiplexing (SM) and quasi orthogonal space-time block coding (QOSTBC) with different code rates. By switching among these signaling modes, the system dynamically trades off between spatial multiplexing and diversity gain according to the instantaneous channel state information. In order to further reduce the computational complexity of decoding, we also introduce the lattice-reduction (LR) technique in the proposed system. The performance advantages of the proposed multi-mode system are demonstrated via extensive computer simulations. View full abstract»

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  • A multi-path data exclusion model for RSSI-based indoor localization

    Page(s): 336 - 340
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (175 KB) |  | HTML iconHTML  

    Positioning a device with the only help of an RF transmitter in an indoor environment is difficult because of the complexity and of the unpredictable nature of radio propagation in such a scenario. The effects of fading, multipath, shadowing make it difficult to infer distance between two points from a blind measurement of the signal attenuation. However, the Received Signal Strength Indicator (RSSI) remains a popular ranging technique when it comes to the Internet of Things, as it does not require dedicated or expensive hardware. The variability of the RSSI is often addressed by modeling channel attenuation by a parametric model like the log-normal shadowing. Such model parameters are generally evaluated by maximum likelihood estimation (MLE). In this paper, we confront this technique to an indoor realistic testbed and show that it achieves a low accuracy. We propose to use an alternate model named biased log-normal shadowing model that is able to alleviate the effects of multipath and show that MLE on this biased model achieves a better precision. View full abstract»

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  • A new standard activity in IEEE 802.22 wireless regional area networks: Enhancement for broadband services and monitoring applications in TV whitespace

    Page(s): 108 - 112
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB) |  | HTML iconHTML  

    This paper presents the recent update on IEEE 802.22 wireless regional area network (WRAN) working group activities, especially IEEE 802.22b task group (IEEE 802.22b) for enhancement for broadband services and monitoring applications in TV whitespace (TVWS). As an action to extend and enhance IEEE 802.22 applications, a new IEEE 802.22b task group has been formed and approved by the IEEE 802 executive committee. The objective of IEEE 802.22b specifies new amendment of IEEE 802.22-2011 to include low complexity monitoring applications, as well as enhance the currently available broadband services. In this paper, we briefly introduce use cases and technical topics, as well as future direction on system design, system classes such as introduction of low complexity devices, possible access methods, throughput improvement options etc. View full abstract»

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  • A non-invasive detection of respiration by using ultra wideband signals

    Page(s): 514 - 518
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (217 KB) |  | HTML iconHTML  

    Recent research on extracting biological information by radio waves has attracted much attention for application in disaster areas or medical scenes. This technology enables the collection of biological information even from people not wearing any sensors such as RFID (Radio Frequency IDentification) tags. The purpose of this paper is to detect respiration non-invasively regardless of a person's shape using ultra wideband signals, which are less harmful to the body or medical equipment. The respiratory detection experiment involves the analysis of reflected waves from the target body using two double-ridged guide horn antennas. The received power in the measurement system varies with time as a function of respiration. By measuring the periodicity, the possibility of non-invasive detection of respiration was demonstrated. View full abstract»

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  • A novel distributed cluster combination method for CoMP in LTE-A system

    Page(s): 614 - 618
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (230 KB) |  | HTML iconHTML  

    In LTE-A system, the coordinated multipoint transmission (CoMP) strategy is usually implemented among a group of base stations called coordination cluster. In this paper, in order to obtain a better balance between cell-edge UE performance promotion and overhead, a novel distributed coordination cluster combination method is proposed, in which the coordination cluster no longer keeps static but is dynamically combined by multiple sectors, an index called effective cell-edge UE number is used to quantify the performance of cluster combination, and a utility function based on collision strategy is employed to guarantee that the best combination decision is made. A revised joint proportional fairness scheduling method is also proposed to improve the frequency resource utilization. The system level simulation shows that the novel method outperforms Network-defined method, and very approximates to UE-specific method when maximum cluster size is set to 6. Meanwhile, its overhead and delay are both very low. View full abstract»

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  • A novel interference avoidance scheme based on blind polarization signal processing for cognitive Femtocell network

    Page(s): 40 - 44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (795 KB) |  | HTML iconHTML  

    Femtocell technology has been recently proposed as a potential solution to improve spectrum efficiency. However, serious interference problem has also been brought in as well as the benefits. In this paper, a novel interference avoidance scheme based on blind polarization signal processing for cognitive Femtocell network is proposed. Femtocell network uses the polarization state which is orthogonal to the macrocell user (MUE) so as to avoid the interference to MUE. Cognitive Femtocell base station (FBS) obtains information from MUE firstly and then obtains polarization state for the whole Femtocell network with blind polarization signal processing without any prior information of channel between FBS and MUE. Polarized noise suppression method is also included to mitigate the random interference from additive white Gaussian noise to the arrived signal at FBS. Numerical simulation results show that the scheme can perform well under flat Rayleigh-fading channel. View full abstract»

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  • A novel secure wireless communication using side information from spatially distributed nodes in private wireless network

    Page(s): 453 - 457
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (138 KB) |  | HTML iconHTML  

    This paper proposes a novel secure wireless communication scheme using side information transmitted from nodes spatially distributed in private wireless network. In the proposed scheme, spatially distributed nodes apart from source and destination pair transmits the side information which is necessary to encrypt and decrypt the secret information. Because a detectable region of the side information can be spatially separated from that of the encrypted information by transmitting the side information from the spatially distributed node, the exposure region where the secret information is interpreted can be narrowed. Numerical results prove that the proposed scheme reduces the area of exposure region and the opportunity of eavesdropping by a malicious node. View full abstract»

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  • A Polarization-Amplitude-Phase Modulation scheme for the Power Amplifier energy efficiency enhancement

    Page(s): 369 - 373
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (303 KB) |  | HTML iconHTML  

    To improve the Power Amplifier (PA) energy efficiency, a Polarization-Amplitude-Phase Modulation (PAPM) scheme in wireless communication, which introduces the signal's Polarization State (PS), amplitude and phase as the information-bearing parameter, is proposed. Since that the transmitted signal's PS can be completely determined by a pair of orthogonal dual-polarized antennas and is unaffected by the PA, using the PS as the information-carrying parameter can further increase the data rate and allow PA to work in its non-linear region. Thus, the PA energy efficiency can be enhanced. On the basis of the above, to optimize the PA energy efficiency, an optimization problem regarding the output back off value and the ratio between the data carried by the PS and the amplitude-phase has been formulated, and the distribution of the optimum solutions is presented. The simulation results show that, with the same symbol error rate and channel state, PAPM can reduce the energy consumption per bit by 50% compared with QAM on average. View full abstract»

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  • A primary study on location estimation system for ad-hoc networks with considering incorrect nodes

    Page(s): 577 - 578
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (65 KB) |  | HTML iconHTML  

    Ad-hoc mesh network can be a practical and feasible workaround when mobile phone networks will be unavailable in large-scale disasters. This paper aim to construct a location estimation system for temporary deployed ad-hoc mesh networks with considering incorrect anchor nodes. View full abstract»

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  • A space-time block code with temporal and spatial modulation

    Page(s): 519 - 523
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (169 KB) |  | HTML iconHTML  

    This paper proposes a space-time block code with temporal and spatial modulation to increase spectral efficiency with low decoding complexity. Compared to the conventional space-time block code with spatial modulation (STBC-SM) that transmits Alamouti's STBC symbols with the combinations of the transmission antennas, the proposed STBC-SM further expands the transmission time slots. The transmitter of the proposed STBC-SM has three antennas and uses three time slots for transmitting STBC symbols whereas that of the conventional STBC-SM uses two time slots. In this paper, the validity of the proposed STBC-SM is confirmed by the numerical evaluation in terms of the bit error rate and the spectral efficiency. The results show the proposed STBC-SM can improve the spectral efficiency and the bit error rate of the conventional STBC-SM. View full abstract»

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  • A study of network infrastructure optimization for data center servers

    Page(s): 164 - 168
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (844 KB) |  | HTML iconHTML  

    Data center plays an important role in cloud computing. Cloud computing provides novel perspectives in Internet technologies and raises issues in the architecture, protocol, and implementation of existing networks and data centers. Although various cloud-based data center architectures have been proposed in recent years, some challenging issues, e.g., congestion control, load balancing and energy efficiency, still need to be addressed. In this paper, we present the designs of network architecture for data center servers, and then analyze and compare several promising solutions to tackle those challenging problems. View full abstract»

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  • A study on channel prediction for dynamic spectrum control aided spectrum sharing

    Page(s): 30 - 34
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (634 KB) |  | HTML iconHTML  

    This paper proposes a channel prediction scheme suitable for selfish dynamic spectrum control (Selfish DSC) in which each link dynamically chooses a necessary amount of spectrum having the highest signal to noise plus interference power ratio (SINR) from the entire shared band. For channel prediction in such a Selfish DSC, although it is mandatory to predict channel frequency response for the entire system band to choose the best spectrum for the next transmission, it is quite difficult because each link can measure only a part of the band. In other words, each user has to solve an ill-conditioned least square (LS) problem. Thus, the proposed scheme chooses a certain amount (which is smaller than the total amount) of spectrum with the highest SINR, followed by the selection of the rest of spectrum uniformly from the other part to mitigate the impact of ill-conditioned LS problem. Then data and reference signals are transmitted via the selected spectrum. Numerical analysis reveals that the proposed scheme can achieve satisfactory average channel capacity due to a good balance between frequency diversity effect by the dynamic spectrum selection and enhanced reliability by the selection of a certain amount of spectrum uniformly from the entire system band. View full abstract»

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  • A trust and distrust mechanism for a social network-based recommendation system

    Page(s): 172 - 176
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (318 KB) |  | HTML iconHTML  

    As people and their acquaintances are connected with one another to form a social network, social network-based recommendation systems (SNRS) enable people to make decisions based on previous experiences and knowledge of acquaintances. SNRS are implemented to take advantage of the acquaintance relationships, which form the essential links within social networks, to enable people in need of item purchasing recommendations to send requests for recommendations and receive recommendations from people throughout the network. Each person in the social network maintains a pair of trust and distrust ratings for each of their acquaintances and updates the ratings based on usefulness of received from the corresponding acquaintance. A pair of trust and distrust rating is used instead of just a single trust rating where the assumed distrust rating can be derived from the trust rating. In the proposed trust and distrust mechanism, trust represents the perceived risk of choosing a recommendation from the corresponding acquaintance while distrust is a protective measure indicating the level of doubt on the level of trust that is assigned to the same acquaintance. The proposed mechanism corresponds to studies indicating that the trust and distrust are determined separately, with the level of trust being based on a relatively rational evaluation while the level of distrust is based more on fear and other irrational emotions. When the level of distrust rises over a certain threshold for an acquaintance, recommendations received from the acquaintance will not be considered during the decision making process until the level of distrust falls below the threshold. The simulation used for this study utilizes software agents that are connected with one another via a social network to model the behavior of people when soliciting recommendations and providing recommendations. View full abstract»

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  • A VLF to UHF propagation model for evaluation of high-speed railway electromagnetic emissions in outside world

    Page(s): 414 - 418
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (715 KB) |  | HTML iconHTML  

    Considering that recent european high-speed railway system has a traction power system of 2 × 25kV 50Hz, which causes electromagnetic emission for the outside world, it is important to dimension the railway system emissions, using a frequency/distance dependent propagation model. This paper presents an enhanced theoretical model for VLF to UHF propagation, railway system oriented. It introduces the near field approach (crucial in low frequency propagation) and also considers the source characteristics and type of measuring antenna. Simulations are presented, and comparisons are set with earlier far field models. View full abstract»

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  • Accurate analysis of delay and power consumption of LTE DRX mechanism with a combination of short and long cycles

    Page(s): 384 - 388
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (872 KB) |  | HTML iconHTML  

    Long-term evolution (LTE) has been heralded as the 4G mobile communication standard to meet the demand for high-speed data transmission. But the heavy processing requirement on the user equipment (UE) leads to excessive power consumption. Discontinuous reception (DRX) is an important mechanism to tackle the issue. Delay and power saving are two contradictory performance indicators associated with DRX. This paper makes a rigorous analysis of the delay incurred and power saving achieved by a DRX scheme that uses a mix of short and long cycles. The correctness of the analysis is validated by simulation. Moreover, the values of key parameters values are varied to assess their impact on the performance of DRX. View full abstract»

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  • Adaptive one-way and two-way relaying for MIMO relay networks

    Page(s): 286 - 290
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (211 KB) |  | HTML iconHTML  

    This paper proposes a modified full-duplex one-way (FD-OW) relaying and discusses an adaptive relaying based on modified FD-OW relaying and half-duplex two-way (HD-TW) relaying. The modified FD-OW relaying applies cooperative relaying scheme to conventional FD-OW relaying to achieve diversity gain. The optimal relaying transformation matrices that maximize the capacity for each relaying scheme are derived to estimate the ability of adaptive relaying. The result of performance evaluation demonstrates the ability of adaptive relaying to improve the outage capacity. View full abstract»

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  • Affinity Propagation with file similarity based clustering for P2P file sharing in VANET

    Page(s): 70 - 74
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (493 KB) |  | HTML iconHTML  

    Vehicular Ad-hoc Network (VANET) has been widely discussed and many issues have been identified these years. Due to VANET's rapid change of structure and unstable properties, many studies proposed to use clustering architecture to improve network performance. However, most of the cluster architectures are suitable only for broadcasting applications and not applicable to p2p file sharing. In this paper, we propose a File-based Affinity Propagation Cluster (FAPC) that has the joint advantages of movement similarity and file similarity. Besides, FAPC uses adaptive cluster head election time to determine the most appropriate cluster time interval to elect cluster head adapting to traffic density. FAPC is proved to be applicable to p2p file sharing in VANET. Simulations results show that FAPC outperforms both Shea's APROVE [1] and Taleb's Social Cluster-based Overlay Structure [2] in terms of query hit ratio, retrieved file ratio, average number of clusters and average cluster head duration. View full abstract»

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