In this paper, we study the performance of network-coded cooperativediversity systems with practical communication constraints. More specifically,we investigate the interplay between diversity, coding, and multiplexing gainwhen the relay nodes do not act as dedicated repeaters, which only forward datapackets transmitted by the sources, but they attempt to pursue their owninterest by forwarding packets which contain a network-coded version ofreceived and their own data. We provide a very accurate analysis of the AverageBit Error Probability (ABEP) for two network topologies with three and fournodes, when practical communication constraints, i.e., erroneous decoding atthe relays and fading over all the wireless links, are taken into account.Furthermore, diversity and coding gain are studied, and advantages anddisadvantages of cooperation and binary Network Coding (NC) are highlighted.Our results show that the throughput increase introduced by NC is offset by aloss of diversity and coding gain. It is shown that there is neither a codingnor a diversity gain for the source node when the relays forward anetwork-coded version of received and their own data. Compared to other resultsavailable in the literature, the conclusion is that binary NC seems to be moreuseful when the relay nodes act only on behalf of the source nodes, and do notmix their own packets to the received ones. Analytical derivation and findingsare substantiated through extensive Monte Carlo simulations.
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