SINR balancing techniques for a cognitive radio relay network with multiple peer-to-peer users

We consider multiple peer-to-peer secondary users that are assisted by multiple multi-antenna relays for mitigating spatial interference and forwarding signals. We propose a joint semidefinite programming and geometric programming based optimization technique to determine optimum relay transceiver matrices and power allocation at the source and the relay so that all users are able to transmit signals simultaneously in the same frequency band while maximizing the balanced signal-to-interference and noise ratio (SINR) of the users and ensuring interference leakage to the primary user is below a specific threshold. We evaluate the performance of the proposed scheme in terms of the mean SINR for different number of relays and transmission power at the relays.