{"title":"The Amplify-based Multiple-Relay Multiple-Access Channel: Capacity Region and MAC-BC Duality","authors":"A. D. Coso, C. Ibars","doi":"10.1109/ITWITWN.2007.4318059","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318059","url":null,"abstract":"We consider the multiple access channel (MAC) assisted by N parallel relays that only have buffering and amplifying capabilities. For this channel, we derive the capacity region applying results on MAC with finite memory. Later, the MAC-broadcast (BC) duality is demonstrated using duality arguments for vector channels. Indeed, the capacity region of the Gaussian amplify-based BC with N parallel relays is shown to be the capacity region of the amplify-based MAC with sum power constraint, and to be achievable through dirty paper coding.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"97 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":"121581213","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}
{"title":"Space-Time Block Codes using Diversity Transform","authors":"A. Salomon, O. Amrani","doi":"10.1109/ITWITWN.2007.4318060","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318060","url":null,"abstract":"This paper presents a method for constructing space-time block codes for multiple-input multiple-output (MIMO) Rayleigh fading channels. It employs orthogonal designs combined with the so-called diversity transform. Orthogonal designs provide the maximum diversity order for a given number of transmit and receive antennas. The diversity transform relies on unitary transforms that increase the channel alphabet; it does not alter the distance between input sequences, nor the bandwidth or information rate. A scheme of high diversity gain is tailored for any antenna array and signal constellation. Simulation results reveal that this scheme attains higher coding gains than other results known in the art.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"13 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":"122299769","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}
{"title":"A Decentralized Approach to Network Coding Based on Learning","authors":"Mohammad Jabbarihagh, F. Lahouti","doi":"10.1109/ITWITWN.2007.4318025","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318025","url":null,"abstract":"Network coding is used to efficiently transmit information in a network from source nodes to sink nodes through intermediate nodes. It has been shown that linear coding is sufficient to achieve the multicast network capacity. In this paper, we introduce a method to design capacity achieving network codes based on reinforcement learning and makes using the market theory concepts. We demonstrate that the proposed algorithm is decentralized and polynomial time complex; while it constructs the codes much faster than other random methods with the same complexity order, especially in large networks with small field sizes. Furthermore, the proposed algorithm is robust to link failures and is used to reduce the number of encoding nodes in the network.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"45 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":"128163895","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}
{"title":"On the Limits of Spatial Reuse and Cooperative Communication for Dense Wireless Networks","authors":"Venkatesh Ramaiyan, Anurag Kumar","doi":"10.1109/ITWITWN.2007.4318071","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318071","url":null,"abstract":"We consider a dense ad hoc wireless network comprising n nodes confined to a given two dimensional region of fixed area. For the Gupta-Kumar random traffic model and a realistic interference and path loss model (i.e., the channel power gains are bounded above, and are bounded below by a strictly positive number), we study the scaling of the aggregate end-to-end throughput with respect to the network average power constraint, P macr, and the number of nodes, n. The network power constraint P macr is related to the per node power constraint, P macr, as P macr = np. For large P, we show that the throughput saturates as Theta(log(P macr)), irrespective of the number of nodes in the network. For moderate P, which can accommodate spatial reuse to improve end-to-end throughput, we observe that the amount of spatial reuse feasible in the network is limited by the diameter of the network. In fact, we observe that the end-to-end path loss in the network and the amount of spatial reuse feasible in the network are inversely proportional. This puts a restriction on the gains achievable using the cooperative communication techniques studied in and, as these rely on direct long distance communication over the network.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"25 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":"126840944","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}
{"title":"Multi-User Gain and Maximum Eigenmode Beamforming for MIMO Systems with Rate Constraints","authors":"L. Ping, Peng Wang","doi":"10.1109/ITWITWN.2007.4318044","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318044","url":null,"abstract":"We consider the sum-power minimization problem for multi-user multiple-input multiple-output (MIMO) systems with rate constraints. We show that significant performance improvements, qualified by multiuser gain (MUG), can be achieved by allowing multiple users to transmit simultaneously on their individual maximum eigenmodes. We also show that a major part of MUG can be achieved even with quite a small number of users and increasing the number of antennas at the base station is an efficient method for maximizing MUG.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"1 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":"129399203","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}
{"title":"Non Traditional Relay Channels: Diversity and Secrecy Gains","authors":"H. E. Gamal","doi":"10.1109/ITWITWN.2007.4318049","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318049","url":null,"abstract":"Summary form only given. In this talk, we report some of the recent results on non traditional relay channels. More specifically, the outage-limited relay channel is discussed first. Here, a simple implementation of the dynamic decode and forward relaying scheme is presented. This scheme achieved the optimal diversity-multiplexing tradeoff for multiplexing gains r les 0.5. In the second part of the talk, we impose a secrecy constraint on the relay channel by introducing an eavesdropper to the basic setup. Several cooperation strategies for enhancing the secrecy capacity are devised, and the corresponding achievable rate-equivocation region is characterized. Of particular interest is the novel noise-forwarding (NF) strategy, where the relay node sends codewords independent of the source message to confuse the eavesdropper. This strategy is used to illustrate the deaf helper phenomenon, where the relay is able to facilitate secure communications while being totally ignorant of the transmitted messages. Furthermore, NF is shown to increase the secrecy capacity in the reversely degraded scenario, where the relay node fails to offer performance gains in the classical setting.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"11 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":"132430671","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}
{"title":"Optimal Code Constructions for SIMO-OFDM Frequency Selective Fading Channels","authors":"Hsiao-feng Lu","doi":"10.1109/ITWITWN.2007.4318022","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318022","url":null,"abstract":"A SIMO-OFDM system with nr receive antennas and Q subcarriers is considered in this paper. Under a frequency-selective Rayleigh fading channel with L multipaths, L < Q, it is first shown that the channel capacity of this channel is same as that of the flat Rayleigh fading channel and is independent of the power-delay profiles. It is also shown that the outage exponent equals dout(r) = Lnr(1-r). Finally we prove that a newly constructed multi-block space-frequency code can be used to reach the optimal diversity-multiplexing gain tradeoff of this channel with optimal diversity gain d-(r) sime Lnr(1-r).","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"51 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":"133177143","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}
{"title":"A Deterministic Model for Wreless Relay Networks an its Capacity","authors":"A. Avestimehr, S. Diggavi, David Tse","doi":"10.1109/ITWITWN.2007.4318021","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318021","url":null,"abstract":"We present a deterministic channel model which captures several key features of multiuser wireless communication. We consider a model for a wireless network with nodes connected by such deterministic channels , and compute the end-to-end capacity when there is a single source and a single destination and an arbitrary number of relay nodes. This capacity has the interpretation of the in ax-flow min-cut solution of a wireline network naturally associated with the deterministic wireless network.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"4 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":"134637781","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}
{"title":"On the Construction of 64-QAM Golay Complementary Sequences","authors":"Ying Li","doi":"10.1109/ITWITWN.2007.4318054","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318054","url":null,"abstract":"The construction of 64-QAM Golay sequences is discussed based on extensions of Lee and Golomb's construction. On length n = 2m sequences, Lee and Golomb reported 496, 808, and 976 first order offset pairs for m=2, 3, 4. We found 724, 972, and 1224 offset pairs from computer search over all first order offset pairs. Some additional pairs can be obtained by adding w = 1 to Case III in Lee and Golomb's offset pair descriptions, others are new and only exist for w>3. The descriptions of new offset pairs and the enumeration of all first order offset pairs are proposed as conjectures. The number of first order offset pairs, [240(m + 1) + 4 + 2(m - 2)(m + 1)], agrees with computer results for ;m=2~6. The peak envelope power upper bound is shown to remain as 4.6667n. An example shows that other 64-QAM Golay sequences not within this construction can be generated using QPSK Golay sequences with third order algebraic normal form.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"503 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":"127036356","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}
{"title":"On the Performance of Joint and Separate Channel and Network Coding in Wireless Fading Networks","authors":"J. Kliewer, Theodoros K. Dikaliotis, T. Ho","doi":"10.1109/ITWITWN.2007.4318067","DOIUrl":"https://doi.org/10.1109/ITWITWN.2007.4318067","url":null,"abstract":"For wireless fading networks where M source nodes wish to multicast their information to N destination nodes via a common relay, it has been shown that network coding at the relay can reduce the number of required transmissions, if the destination nodes overhear M - 1 source nodes transmitting to the relay. Nested coding is a recently proposed alternative where, unlike network coding, physical and network layers are jointly designed. We find that for a given network throughput ideal nested coding in many situations can lead to a significant increase in transmission reliability compared to network coding. We also consider the case of feedback and retransmissions when received packets fail to be decoded. For the case of two source nodes it is shown that by using nested codes the expected number of relay transmissions is reduced. However, for a larger number of source nodes the gain depends on the employed nested coding strategy at the relay.","PeriodicalId":257392,"journal":{"name":"2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks","volume":"77 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":"116742617","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}