We examine the outage capacity of of coded cooperation. Coded cooperation is a wireless user cooperation protocol that integrates cooperative signaling with channel coding. Each user’s code word is partitioned into two subsets that are transmitted from the user’s and the partner’s antennas, respectively. A notable outcome of this research is that, unlike the decode-and-forward protocol that was shown by Laneman to have diversity of one, coded cooperation achieves diversity order in the number of cooperating users. Thus we show that coded cooperation is fundamentally distinct from decode-and-forward, despite their superficial similarities. We also apply our analysis to space-time cooperation and study the effects of cooperation resource allocation. Numerical evaluation of outage expressions show that coded cooperation has a performance advantage across a wide range of SNR over several other cooperation protocols. I.

This chapter rethinks the link abstraction for wireless networks in the context of coopera-tive communications, which has recently received interest as an untapped means for improv-ing performance of relay transmission systems operating over the ever-challenging wireless medium. The common theme of most research in this area is to optimize physical layer per-formance measures without considering in much detail how cooperation interacts with higher layers and improves network performance measures. Because these issues are important for enabling cooperative communications to practice in real-world networks, especially for the increasingly important class of mobile ad hoc networks (MANETs), the goals of this paper are to survey basic cooperative communications and outline two potential architectures for cooperative MANETs. The first architecture relies on an existing clustered infrastructure: cooperative relays are centrally controlled by cluster heads. In another without explicit clustering, cooperative links are formed by request of a source node in an ad hoc, decentralized fashion. In either case, cooperative communication considerably improves the network con-nectivity. Although far from a complete study, these architectures provide modified wireless link abstractions and suggest tradeoffs in complexity at the physical and higher layers.

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Abstract—The problem of retrieving information by a mobile access point from a sensor network where sensors cooperatively transmit messages using a common codebook is considered. It is assumed that there is a probability that a sensor is misinformed with a wrong message, which complicates the information retrieval process. The access point uses the capacity achieving stay- � scheduler that schedules a sensor to transmit for � consecutive code-letters before switching to a new sensor. The random coding exponent is derived as a function of �, and it is shown that there is an optimal � that gives the largest error exponent. The application of low-definition parity-check (LDPC) codes is considered next. It is shown in simulations that the optimal � of the stay- � scheduler for LDPC codes can be inferred from that for the random coding exponent. Index Terms—Cooperative transmission, error exponent, low-density parity-check (LDPC) codes, sensor networks. I.

Submitted to IEEE Trans. Inform. Theory as a Correspondence Very recently, we proposed the row-monomial distributed orthogonal space-time block codes (DOSTBCs) and showed that the row-monomial DOSTBCs achieved approximately twice higher bandwidth efficiency than the repetitionbased cooperative strategy [1]. However, we imposed two limitations on the row-monomial DOSTBCs. The first one was that the associated matrices of the codes must be row-monomial. The other was the assumption that the relays did not have any channel state information (CSI) of the channels from the source to the relays, although this CSI could be readily obtained at the relays without any additional pilot signals or any feedback overhead. In this paper, we first remove the row-monomial limitation; but keep the CSI limitation. In this case, we derive an upper bound of the data-rate of the DOSTBC and it is larger than that of the row-monomial DOSTBCs in [1]. Secondly, we abandon the CSI limitation; but keep the row-monomial limitation. Specifically, we propose the row-monomial DOSTBCs with channel phase information (DOSTBCs-CPI) and derive an upper bound of the data-rate of those codes. The rowmonomial DOSTBCs-CPI have higher data-rate than the DOSTBCs and the row-monomial DOSTBCs. Furthermore, we find the actual row-monomial DOSTBCs-CPI which achieve the upper bound of the data-rate. Index Terms—Cooperative networks, distributed space-time block codes, diversity, single-symbol maximum likelihood decoding.