2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks最新文献_第3页

Normalized Entropy Vectors, Network Information Theory and Convex Optimization 归一化熵向量，网络信息理论和凸优化

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318051

B. Hassibi, S. Shadbakht

{"title":"Normalized Entropy Vectors, Network Information Theory and Convex Optimization","authors":"B. Hassibi, S. Shadbakht","doi":"10.1109/ITWITWN.2007.4318051","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318051","url":null,"abstract":"We introduce the notion of normalized entropic vectors-slightly different from the standard definition in the literature in that we normalize entropy by the logarithm of the alphabet size. We argue that this definition is more natural for determining the capacity region of networks and, in particular, that it smooths out the irregularities of the space of non-normalized entropy vectors and renders the closure of the resulting space convex (and compact). Furthermore, the closure of the space remains convex even under constraints imposed by memoryless channels internal to the network. It therefore follows that, for a large class of acyclic memoryless networks, the capacity region for an arbitrary set of sources and destinations can be found by maximization of a linear function over the convex set of channel-constrained normalized entropic vectors and some linear constraints. While this may not necessarily make the problem simpler, it certainly circumvents the \"infinite-letter characterization\" issue, as well as the nonconvexity of earlier formulations, and exposes the core of the problem. We show that the approach allows one to obtain the classical cutset bounds via a duality argument. Furthermore, the approach readily shows that, for acyclic memoryless wired networks, one need only consider the space of unconstrained normalized entropic vectors, thus separating channel and network coding - a result very recently recognized in the literature.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115023085","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: 33

Achieving Optimal Distortion Exponent of Parallel Quasi-Static Fading Channel with Imperfect CST 利用不完全CST实现平行准静态衰落信道最优失真指数

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318065

Albert W. C. Lim, V. Lau

{"title":"Achieving Optimal Distortion Exponent of Parallel Quasi-Static Fading Channel with Imperfect CST","authors":"Albert W. C. Lim, V. Lau","doi":"10.1109/ITWITWN.2007.4318065","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318065","url":null,"abstract":"We consider transmission of a continuous amplitude i.i.d. source over a M parallel quasi-static Rayleigh fading channels. Due to the non-ergodic nature of the channel, Shannon's source-channel separation theorem does not hold and the optimal performance requires a joint optimization of the source and channel variables. Our goal in this paper is to characterize the expected end-to-end source distortion in the high SNR regime. Defining source distortion exponent as Delta = - limSNRrarrinfin log ED/ SNR, we derive the optimal distortion exponent for any bandwidth expansion ratio b. Our optimality is with respect to system with perfect channel state information at the transmitter (CSIT) and thus refers to the best achievable performance. In particular, we prove the achievability of the source distortion exponent upper bound, derived by considering ergodic channel, with both rate adaptive channel coding diversity and source coding diversity scheme where only imperfect CSIT is available. Although we consider a memoryless Gaussian source in this paper, the derived optimal distortion exponent holds for a general class of source distribution.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124642998","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

On queueing in coded networks - queue size follows degrees of freedom 在编码网络中排队——队列大小遵循自由度

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318066

J. Sundararajan, D. Shah, M. Médard

{"title":"On queueing in coded networks - queue size follows degrees of freedom","authors":"J. Sundararajan, D. Shah, M. Médard","doi":"10.1109/ITWITWN.2007.4318066","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318066","url":null,"abstract":"We propose a new queueing mechanism for coded networks with stochastic arrivals and/or lossy links. In this context, earlier work introduced the notion of \"virtual queues\" which represent the backlog in degrees of freedom. For instance, the work by Ho and Viswanathan defined the achievable rate region for which the virtual queue size is stabilized, using intra-session coding. The queueing scheme that we propose here forms a natural bridge between the virtual queue size and the physical queue size, and thus extends their result to the stability of the physical queues as well. Specifically, we show that the amount of memory used at the transmit buffer in our scheme is upper bounded by the total backlog in the number of linearly independent degrees of freedom. Moreover, our scheme gives an online algorithm for queue update and coding, in the sense that the coding does not happen block by block, but in a streaming manner. The main idea in our scheme is to ensure that the information stored at the sender excludes any knowledge that is common to all receivers. This requires the transmitting node to track the states of knowledge of its receivers. Therefore, if the links are lossy, some form of feedback may be necessary.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116054960","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: 30

Diversity-Multiplexing Gain Trade-off of a MIMO System with Relays 带中继的MIMO系统分集-复用增益权衡

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318029

C. Rao, B. Hassibi

引用次数: 20

Distributed GABBA Space-Time Codes in Amplify-and-Forward Cooperation 扩和前向合作中的分布式GABBA空时码

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318061

B. Maham, A. Hjørungnes

引用次数: 23

Reliable Cooperative Source Transmission with Side Information 具有侧信息的可靠合作源传输

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318024

Deniz Gündüz, E. Erkip

引用次数: 24

On Maximizing Coverage in Gaussian Relay Networks 高斯中继网络中最大覆盖问题

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318027

V. Aggarwal, A. Bennatan, A. Calderbank

引用次数: 15

Packet Retransmission Diversity Schemes for Higher Order Modulation with High Power and Bandwidth Efficiency 具有高功率和带宽效率的高阶调制的分组重传分集方案

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318056

M. Gidlund

{"title":"Packet Retransmission Diversity Schemes for Higher Order Modulation with High Power and Bandwidth Efficiency","authors":"M. Gidlund","doi":"10.1109/ITWITWN.2007.4318056","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318056","url":null,"abstract":"Summary form only given. In this presentation, we present a bandwidth-efficient and power-efficient packet retransmission diversity scheme suitable for improving the performance of linear multi-level modulation schemes, such as pulse amplitude modulation (PAM), phase-shift keying modulation (PSK) and quadrature amplitude modulation (QAM), in wireless systems employing (H)ARQ protocols. Our proposed retransmission diversity scheme considers the interaction between (i) the number of retransmission diversity branches and (ii) the signal space of the modulation scheme, to improve the performance. The concept is to suitably rearrange the symbols (change the bit-to-symbol mapping) between retransmissions, while employing the modulation order M as an extra dimension. In this way the modulation order and the number of retransmission diversity branches together are viewed as creating an augmented signal space of higher dimension than the modulation signal space alone, and this is in turn exploited to improve the transmission quality. Both the robustness and the throughput performance are improved, and the number of retransmissions per packet is reduced compared to conventional packet retransmission schemes. As an extension, we apply the proposed method in conjunction with both space-time block coding and trellis coded modulation. While keeping the same rate and complexity, both analytical and simulation results show a significant improvement of the system performance. Our performance results show that the proposed concept improves the system performance over conventional packet retransmission schemes in both additive white Gaussian noise and flat-fading channels, in particular at low to medium Eb/N0. This proposed scheme is suitable for wireless LANs and future cellular applications due to its low complexity, bandwidth-and power efficiency.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133440085","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

Correlation of Multiple Bent Function Signal Sets 多个弯曲函数信号集的相关

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318052

G. Gong

引用次数: 3

On the Classification of Large Area Sequences 关于大面积序列的分类

2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks Pub Date : 2007-07-01 DOI: 10.1109/ITWITWN.2007.4318053

G. Cresp, H. Zepernick, H. H. Dam

引用次数: 1