Study on comparison of subcarrier coupling schemes over AF realy OFDM networks

다국어 초록 (Multilingual Abstract)

In this paper, we analyze subcarrier coupling which is performed in OFDM multiuser amplify-and-forward relaying networks where a transmitter is communicating with users through an intermediate relay that covers multiple users. There are three methods for subcarrier coupling in the system. First method is ES (Exact Search) which finds all cases. Second method is MTM (Mean Threshold Method) and third method is THF (Two Hop Feedback) method. We analyze channel capacity, system complexity and feedback load of the three cases. ES (Exact Search) method has high complexity and feedback load but the method has best sum rate of users. MTM also has same system complexity. However, feedback load of MTM is decreased by mean threshold and throughput of MTM is lower than ES method in a few users and subcarrier. THF method has same performance. But, THF method has lower feedback load and system complexity than ES method. In addition to this research, there is method which exploits a part of subcarrier in THF method. This method is selected subcarrier of THF method. The method allocates superior carriers to more power. The more allocated power makes system throughput raised. This result is illustrated by simulation figures.