Interference avoidance scheme for wireless multi-user multi-relay networks

In this paper, a cooperative communications scheme with interference management is proposed for wireless multi-user multi-relay networks. The scheme is using on demand decode and forward (DF) half-duplex (HD) relaying protocol, a relay selection method which maximizes the signal-to-noise ratio (SNR) of the second hop, and the maximum ratio combining (MRC) technique to combine the direct and best relay links. To avoid the interference problem and enhance the spectral efficiency, the proposed scheme uses a new relaying protocol based on the constellation real parts of the modulated signals. We derive closed form expressions of the power density function (PDF), the average outage probability, and the average bit error rate (BER) for the proposed scheme, and simulations are used to validate the analytical expressions. The results confirm the advantage of the proposed scheme in enhancing interference management and link reliability.