Analysis And Optimization Of The Performance Of Cooperative Communication Under Non-Ideal Conditions

Using the user-relay transmission in cooperative communication can extend the coverage area, improve the system throughput, cope with fading effectively and reduce outage probability, which can enhance transmission system reliability and quality of service. The collaborate relay and its amount are uncertain, multiple potential relay nodes can be selected from these nodes in actual communication system. How to select the best cooperative nodes from these potential relay nodes reasonably and effectively is very important, which will affect the performance of cooperative network directly. However, in actual communication process, non-ideal factors of delay and co-channel interference will affect the choice of the best relay, and thus adversely affect the throughput and reliability of transmission of the cooperative communication network.This paper introduces the basic model of cooperative wireless communications,forwarding protocols and relay selection strategy based on instantaneous channel state information. Then, we investigate the impact of non-ideal conditions on performance of average bit error rate and channel capacity, including channel estimation error, co-channel interference and feedback delay. Finally, we studied the impact of feedback delay on decode and forward cooperative communication, we proposed a method on optimization of relay selection under outdated channel state information. In outdated channel state, we chose the optimal relay to cooperate with optimal relay selection method. Simulation results show that optimal relay selection reduces the average bit error rate and improves the channel capacity of the system, which improves the performance of communication system.