Performance analysis of adaptive maximal ratio/ selection combining based on full CSI and maximum flow constraint

Cooperative diversity effectively mitigates the fading effect in wireless communication. The system with a source, a destination and the multiple relays is considered for performance analysis. The relay with best channel conditions perform the Decode and Forward (DF) relaying in distributed manner. Then the receiver combines the received signal with the full Channel State Information (CSI) using Maximum Ratio Combining (MRC) for the received instantaneous Signal to Noise Ratio (SNR) of source-relay channel greater than the SNR of relay-destination channel, otherwise Selection Combining (SC) is used to select the channel with maximum SNR. The end-to-end Symbol Error Probability (SEP) with DF relaying for QPSK symbol using proposed combining techniques is derived in closed form, the results shows proposed adaptive combining has better performance than the conventional cooperation scheme.