Practical User Pairing and Selective Network Coding for Multi-User Bidirectional Relaying
A low-complexity user pairing algorithm for the broadcast phase of the XOR-based network coding is presented. The proposed scheme achieves the same spectral efficiency as an exhaustive search approach based on maximizing the sum-rate when network coding is utilized for all transmissions. The proposed scheme is further complemented with an adaptive switch, per user pair, between network coding and conventional relaying to maximize the achievable sum-rate based on the instantaneous link conditions. The proposed user pairing and its extension are based on measurements readily available in today's networks, thus not requiring any signaling overhead.