Reserch Of Relay Selection And Power Allocation In Two-Way Cooperative System

Due to the size and power constraints of mobile terminals, it is difficult to obtain MIMO gainwith multi-antenna. Cooperative communication technology, by sharing the attemas belong todifferent users, can give the destination user spatial diversity gain which is close to the performanceof MIMO. Two-way cooperative communication has obvious advantage in system data ratecompared with one-way cooperative communication. The current two-way research issues includerelay selection (RS) technology, power allocation (PA) technology, relay protocol design andcross-layer optimization. This paper focuses on the relay selection and power allocation, with thefollowing work:(1) The thesis studies the relay selection problem of two-way Amplify-and-Forward(AF)network, and proposes a new relay selection algorithm which considering both relay node SNR anddouble link channel gain. Simulation results verify the advantages of the proposed algorithm inoutage performance.(2) The thesis studies the two-way AF power allocation strategies. First, based on the terminalsSNR threshold, the thesis deduces a new outage probability expression in high SNR region withoptimal relay selected. Then in accordance with the goal of minimizing outage probability, thethesis makes power allocation using the convex optimization method. Later, based on minimizingoutage probability a joint RS and PA optimization is proposed. The joint algorithm is proved to havefull diversity. Simulation results verify the advantages of the proposed algorithm in outageprobability and BER.(3) The thesis studies the PA under OFDM two-way AF multi-relay system. Analysis andderivation verifies that, with subcarrier matching the PA strategy can be converted into a singlerelay policy. Next, if without subcarrier matching a low complexity subcarrier matching policy isproposed to make PA.