Research On Performances Of Cooperative Communication System Based On Network Coding

Though transmission reliability can be improved in wireless networks through cooperative diversity technology, transmission delay will occure when the number of users who need to be cooperated is larger than that of the cooperative nodes. Network Coding is a techonology that can enhance the effectiveness of the network, besides, the outage probability is reduced. This paper mainly deals with the performances of the system which combined the two technologies together. The works are as follows:(1) The key technologies in cooperative communications and network coding are descripted in detail, and the simulation results and analysis of Amplify and Forward strategy and Decoded and Forward strategy are given.(2) The outage probabilities are anlysized in the single-user without cooperative node system, single-user with a cooperative node system, two-users without cooperative node system and two-users with a cooperative node system, meanwhile, the simulation results are given. The results show that the outage probability increases with the increasing number of the users under the same number of cooperative nodes. The probabilities drop when the number of cooperative nodes increases.(3) The outage probabilities of deterministic network coding, opportunistic network coding and complex field network coding are anylized in two-user single relay distributed antenna system, the probabilities are compared with that of traditional way, the strategies are expanded to multi-users distributed antenna system. The results show that network coding improves the network throughput for it consumes less time slots, and it can reduce the system outage probability when there is no error between the user and the relay. Opptunistic network coding has the lowest outage probability when there are errors between users and relay, however, the complexity is the largest. The outage probability of determisnistic network coding is higher than traditional way when the error rate is high, complex field network coding has the largest outage probability.(4) The performances of the collaboration strategies based on traditional route, deterministic network coding and opportunistic network coding in two-user collaborative system are anlysized, and the outage probabilities formulas are derived. Then the simulation results are given. The results show that the network coding can reduce the system outage probability effectively. The deterministic network coding can improve the system throughput, but it has a higher collaboration demand. The opportunistic network coding has the lowest outage probability, but the complexity is the highest, and there is no increasement in system throughput. In the end, strategy based on network coding in multi-user collaborative system is described.