A Multiple-Relay Communication Protocol for Achieving Fairness in Dense Networks

Increasing the density of base stations deployment is regarded as a means to satisfy the growing demand of wireless connectivity over a shared bandwidth, however, increasing the disparity in the service received by each user. Fairness can be realized by dynamically allocating resources to users using detailed channel state information at the transmitter (CSIT), which constitutes an expensive overhead, especially, for dense networks. One solution to improve the fairness without CSIT is to introduce spatial diversity through the use of relays in combination with physical-layer network coding (PNC). Most relaying-PNC solutions focus on the particular case of the two-way relay channel or they require additional relays and a large transmission time. In this paper, we propose a multiple-relay communication protocol (MRCP) for achieving fairness in dense networks. It exploits spatial diversity without requiring additional relays since it uses the base stations as relays. Furthermore, MRCP is applicable to an arbitrary number of base stations and users, while keeping a small transmission time. We show that our approach achieves the highest max-min fairness among users and almost full diversity with asymmetric transmissions.