A Radio Resource Management Strategy for Downlink Cooperation in Distributed Networks

Downlink cooperation between base stations is a simple, efficient alternative to macrodiversity for providing QoS continuity during mobility in distributed cellular networks. It brings cooperation diversity and only requires data forwarding between base stations. This paper presents a strategy for downlink cooperation triggering, resource allocation and power control in an OFDMA-based system. Power control aims at maximizing the equivalent capacity that is achieved thanks to the diversity brought by relaying, while taking into account inter-cell interference. We use an iterative method which dedicates a proportion of the total power to relayed users. Simulation results show that our method increases capacity at any load. It importantly reduces the rejection probability thanks to SIR increase of users at cell's border. The paper also shows that cooperation should be limited to cell-border users for restricting additional resource consumption, and that it should make use of diversity as much as possible.