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GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.最新文献

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A symbol decision scheme to mitigate effects of scintillations and MAIs in optical atmospheric PPM-CDMA systems 一种减轻大气PPM-CDMA系统中闪烁和MAIs影响的符号决策方案
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1578016
Kohki Ohba, T. Hirano, T. Miyazawa, I. Sasase
{"title":"A symbol decision scheme to mitigate effects of scintillations and MAIs in optical atmospheric PPM-CDMA systems","authors":"Kohki Ohba, T. Hirano, T. Miyazawa, I. Sasase","doi":"10.1109/GLOCOM.2005.1578016","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1578016","url":null,"abstract":"In optical atmospheric (OA) pulse position modulation (PPM) code division multiple access (CDMA) systems, the conventional scheme which applies the maximum-value detection has a serious problem that the multiple access interferences (MAIs) become large due to scintillations. In this paper, to mitigate both effects of scintillations and MAIs, we propose a symbol decision scheme by using the comparing detection. In our proposed scheme, the minimum output in all weighted positions is detected in each PPM slot. Then, the maximum-value out of the minimum outputs is detected, and, the symbol corresponding to the PPM slot in which the output has the maximum-value is decided. Since the received symbol is correctly decided as long as there is at least one weighted position without MAIs in other PPM slots, the proposed scheme can mitigate both effects of MAIs and scintillations. We show that the proposed scheme can improve the bit error rate performance","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133359310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
Error performance of multicarrier CDMA in frequency-selective fading 频率选择性衰落下多载波CDMA的误差性能
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1577910
Dongning Guo
{"title":"Error performance of multicarrier CDMA in frequency-selective fading","authors":"Dongning Guo","doi":"10.1109/GLOCOM.2005.1577910","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1577910","url":null,"abstract":"This paper extends a previous work on direct-sequence code-division multiple access (DS-CDMA) to multicarrier (MC) CDMA systems. New results on the error performance of a family of multiuser detectors for MC-CDMA are obtained using the replica method, which was originally developed in statistical physics. The central result is the \"decoupling principle\", namely, an MC-CDMA channel with frequency-selective fading followed by a generic multiuser detection front end can be decoupled into a bank of single-user fading channels in the large-system limit. Thus conditioned on one's fading coefficients, each user essentially experiences an equivalent single-user Gaussian channel with a degradation in the signal-to-noise ratio (SNR) in lieu of multiaccess interference. A set of joint equations is identified that determine the degradation for each user, known as the multiuser efficiency. The result applies to arbitrary input distribution and SNRs, and to optimal multiuser detection, as well as various other suboptimal schemes.","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115237820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
A playback-adaptive approach for video streaming over wireless networks 无线网络视频流的自适应播放方法
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1578459
Mohamed S. Hassan, M. Krunz
{"title":"A playback-adaptive approach for video streaming over wireless networks","authors":"Mohamed S. Hassan, M. Krunz","doi":"10.1109/GLOCOM.2005.1578459","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1578459","url":null,"abstract":"Video streaming over wireless networks is challenged with the time-varying nature of the underlying channels and the stringent requirements of video applications. In this paper, we propose a new scheme for streaming video over wireless channels. The scheme is designed to prevent potential playback discontinuities that may result due to quality variations of the wireless link while gracefully degrading the rendered video quality. We approximate the frame delay statistics and playback process by a simple queueing model. In this queueing system, the rates at which frames are received and played back are occupancy-dependent. This allows us to compute the steady-state probability of the playback buffer occupancy. This in turn, allows us to obtain an expression for the probability of starvation which we use to determine a threshold occupancy and hence the optimal source and channel rates for the upcoming frames. Simulation and numerical investigations are carried out to study the interactions among various key parameters and verify the adequacy of the analysis","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"235 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115673703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 16
Upper bounds on MIMO channel capacity with channel Frobenius norm constraints 信道Frobenius范数约束下MIMO信道容量的上界
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1577902
Zukang Shen, J. Andrews, B. Evans
{"title":"Upper bounds on MIMO channel capacity with channel Frobenius norm constraints","authors":"Zukang Shen, J. Andrews, B. Evans","doi":"10.1109/GLOCOM.2005.1577902","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1577902","url":null,"abstract":"The motivation of this paper is to find the class of channels that provides the largest capacity with both the transmit power constraint and channel Frobenius norm constraints. We study both the point-to-point case and the broadcast case. For point-to-point MIMO channels, the optimal channels must have T* equal singular values, where T* is dependent on the available transmit power and the channel Frobenius norm. This result agrees with the previous work by Chiurtu et al. For multiuser broadcast channels, we obtain an upper bound on the sum capacity. We also show that the bound is asymptotically tight for high SNR when all user channels have the same Frobenius norm constraint and N/sub t/ /spl ges/ KN/sub r/, where N/sub t/ and N/sub r/ are the numbers of transmit and receive antennas and K is the number of users.","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124869260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 11
On the multiple-access capability of a shared Rayleigh wireless channel with binary feedback 基于二进制反馈的共享瑞利无线信道的多址性能研究
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1577901
K. Hamdi
{"title":"On the multiple-access capability of a shared Rayleigh wireless channel with binary feedback","authors":"K. Hamdi","doi":"10.1109/GLOCOM.2005.1577901","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1577901","url":null,"abstract":"In this paper we consider the capacity of a Rayliegh faded wireless channel that is shared by K independent transmitter-receiver pairs. No cooperation is assumed between the different pairs. We examine the possible gain in the sum rate capacity when a binary side information is passed by each receiver to its corresponding transmitter on whether the instantaneous local signal-to-interference-plus-noise-ratio (SINR) is greater or less than a given threshold, and transmitters adapt their transmission power accordingly. It is shown that a substantial improvement in the channel capacity can be achieved by using this \"opportunistic\" transmission strategy. Our numerical results reveal that the total sum capacity increases linearly with the logarithm of the number of users sharing the channels.","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"29 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120910829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Multi-packet signature detection using prefix bloom filters 使用前缀布隆过滤器的多包签名检测
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1577961
N. S. Artan, H. J. Chao
{"title":"Multi-packet signature detection using prefix bloom filters","authors":"N. S. Artan, H. J. Chao","doi":"10.1109/GLOCOM.2005.1577961","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1577961","url":null,"abstract":"It is now a fact that manual defenses against worm epidemics are not practical. Recently, various automatic worm identification methods are proposed to be deployed at high-speed network nodes to respond in time to fast infection rates of worms. Unfortunately, these methods can easily be evaded by fragmentation of the worm packets. The straightforward defragmentation method is not applicable for these high-speed nodes, due to its high storage (memory) requirement. In this paper, this problem, namely the multi-packet signature detection problem is addressed using a defragmentation-free, space-efficient solution. A new data structure - prefix bloom filters - along with a new heuristic, called the chain heuristic is proposed to significantly reduce the storage requirement of the problem, so that multi-packet signature detection becomes feasible for high-speed network nodes.","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130684598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 19
Model for time-varying quality of speech services 时变语音服务质量模型
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1577626
Zhan Chen, H. Nakazato
{"title":"Model for time-varying quality of speech services","authors":"Zhan Chen, H. Nakazato","doi":"10.1109/GLOCOM.2005.1577626","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1577626","url":null,"abstract":"Speech services are widely deployed on new communication infrastructures. However, compared with traditional infrastructures, the ever varying conditions are native of these new infrastructures. Modeling the time-varying speech quality becomes an urgent issue. This paper proposes a computable model for time-varying speech quality evaluation, called M-Model. Considering the time-varying issue, EWMA is used in the model. M-Model is validated by a subjective experiment. The model indicates that time-varying quality with extremely high frequency does not affect perceived quality at all. In addition, we observed that the recency effect influences not only the perceived overall quality but also the perceived instantaneous quality.","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128618765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 11
Performance analysis of multicarrier DS-CDMA with imperfect power control and variable spreading factors 不完全功率控制和可变扩频因子的多载波DS-CDMA性能分析
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1578500
Li-Chun Wang, Chih‐Wen Chang
{"title":"Performance analysis of multicarrier DS-CDMA with imperfect power control and variable spreading factors","authors":"Li-Chun Wang, Chih‐Wen Chang","doi":"10.1109/GLOCOM.2005.1578500","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1578500","url":null,"abstract":"The MC-DS-CDMA possesses the advantages of the immunity against multipath dispersion of orthogonal frequency division multiple access (OFDM) and the flexibility of the time-domain and frequency-domain spreading technique. However, power control errors (PCE) may significantly degrade the performance of the MC-DS-CDMA system. In this paper, we propose an easily computed analytical method to evaluate the bit error rate performance of the multi-rate MC-DS-CDMA system with the time/frequency 2-domain spreading subject to PCE. Furthermore, the proposed analysis also considers the effect of multiple access interference (MAI) from all the subcarriers in the multi-rate MC-DS-CDMA system. We find that power control errors will offset the gain of frequency domain spreading. More importantly, the larger the value of frequency domain spreading, the more the sensitivity to PCE","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131998805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Coded layered space-time transmission with signal space diversity in OFDM systems OFDM系统中信号空间分集的编码分层空时传输
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1578494
Jihoon Kim, Inkyu Lee
{"title":"Coded layered space-time transmission with signal space diversity in OFDM systems","authors":"Jihoon Kim, Inkyu Lee","doi":"10.1109/GLOCOM.2005.1578494","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1578494","url":null,"abstract":"In multiple antenna systems, vertical Bell Labs Layered Space-Time (V-BLAST) systems enable very high throughput by nulling and cancelling at each layer detection. In this paper, we propose a V-BLAST system which combines with signal space diversity technique. The benefit of the signal space diversity is that we can obtain an additional gain without extra bandwidth and power expansion by applying inphase/quadrature interleaving and the constellation rotation. Through simulation results, it is shown that the performance of the proposed system is less than 0.5 dB away from the ideal upper bound","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128721601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
Joint channel estimation and prediction for OFDM systems OFDM系统联合信道估计与预测
GLOBECOM '05. IEEE Global Telecommunications Conference, 2005. Pub Date : 2005-12-01 DOI: 10.1109/GLOCOM.2005.1578065
I. Wong, B. Evans
{"title":"Joint channel estimation and prediction for OFDM systems","authors":"I. Wong, B. Evans","doi":"10.1109/GLOCOM.2005.1578065","DOIUrl":"https://doi.org/10.1109/GLOCOM.2005.1578065","url":null,"abstract":"Adaptive OFDM improves the system throughput by adjusting transmission parameters based on channel state information (CSI) estimated at or received by the transmitter. The improvement, however, is conditioned on the quality of the CSI, which can be compromised by estimation and quantization errors, and more significantly by delay. Channel prediction has been previously proposed to combat feedback delay. In this paper, a novel OFDM channel prediction algorithm that uses a 2 times 1-dimensional frequency estimation to determine the time-delays and Doppler frequencies of each propagation path is investigated. The algorithm assumes a general far-field scatterer, frequency-selective wireless channel model and hence is applicable to a wide variety of wireless channel conditions. It is shown that the method requires less feedback information and has better mean-squared error performance than previous methods. We provide simulation results for IEEE 802.16e channels","PeriodicalId":319736,"journal":{"name":"GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125608544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 38
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