Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học được đăng trên tạp chí toán học quốc tế đề tài: Opportunistic wireless network coding with relay node selection | Kim and Lee EURASIP Journal on Wireless Communications and Networking 2011 2011 196 EURASIP Journal on . http content 20ii i i96 Wireless Communications and Networking a SpringerOpen Journal RESEARCH Open Access Opportunistic wireless network coding with relay node selection Jangseob Kim and Jungwoo Lee Abstract Broadcasting nature of wireless communications makes it possible to apply opportunistic network coding OPNC by overhearing transmitted packets from a source to sink nodes. However it is difficult to apply network coding to the topology of multiple relay and sink nodes. We propose to use relay node selection which finds a proper node for network coding since the OPNC alone in the topology of multiple relays and sink nodes cannot guarantee network coding gain. The proposed system is a novel combination of wireless network coding and relay selection. In this paper with the consideration of channel state and potential network coding gain we propose several relay node selection techniques that have performance gain over the conventional OPNC and the conventional channelbased selection algorithm in terms of average system throughput. 1 Introduction Channel coding concept is used to mitigate the influence of noise and interferences in the physical layer. In 1 it was also shown that we can get coding gain in higher layers. Compared to the routing and scheduling techniques that are devised to prevent bottlenecks of packets from different senders Alswede et al. 2 showed a way of making use of this disadvantage and showed that the achievable rate can be increased by applying certain innetwork processing at an intermediate node when packets are received at the node simultaneously. This type of innetwork processing is called network coding. Routing can be treated as a special case of network coding which is a simple permutation. Network coding has received attention since it can enhance system throughput and reliability. For throughput network .
