Research On Cooperative Relay Communications Network And Energy Harvesting Technology

Whether in the theory or in the engineering, the cooperative relay communications system makes a sense. Meanwhile, the research on the energy harvesting attracts more and more attention. For the amplify-and-forward cooperative relay communications system under the imperfect channel state information(CSI), we consider the impact of the channel estimation error on the performance of the system based on which we summarize four kinds of power allocation schemes to improve the system performance. At last, we validate the results by MATLAB. For the decode-and-forward cooperative relay communications system based on the technology of energy harvesting under perfect channel state information, we study the system performance, analyze the relation between the performance and the influencing parameters and validate the results by MATLAB. Specifically, the main contributions of this thesis are summarized as follows: 1. With the imperfect CSI, we focus on the performance and power allocation schemes of the two-way cooperative relay communications system based on the amplify-and-forward protocol under the Rayleigh fading channel.For the system performance, we consider the outage probability and the bit error rate based on the effective signal noise ratio(SNR):(1) For the outage probability, we present the accurate expression and the approximate expression at the high SNR region. Then we consider the error floor when the SNR is infinite. At last, we validate the results of the outage probability and the error floor by MATLAB.(2) For the symbol error rate, we present the accurate expression, approximate expression and the error floor for the single relay system. Then we summarize the expression of the bit error rate for the multiple relays system. At last, we validate the variation tendency of performance and the error floor of the system by MATLAB.For the power allocation, we focus on the multiple relays and the best relay system:(1) For the multiple relays, we introduce the scheme aiming at minimizing the outage probability and the bit error rate while satisfying the demand of the system and individual power.(2) For the best relay, because of involving the outage probability of the nodes, the average symbol error rate and the power restriction, we summarize three power allocation schemes to improve the performance of the system. In the end, we validate them by MATLAB.2. With the perfect CSI, we focus on the performance of the energy harvesting cooperative relay system based on the decode-and-forward protocol under the Rayleigh and Nakagami-m fading channels.For the system performance, we consider the outage probability and the throughput based on the power splitting relay and time switching relay protocols: Firstly, we derive the exact expression of the system outage probability and the throughput under two kinds of fading channels. Then we analyze the relation between the performance and the influencing parameters(the system SNR, the target transmission rate, the power splitting parameter, the time switching parameter, the location of the relay, the fading channel parameters and the energy conversion efficiency). At last, we validate the results by MATLAB.