A Low Complexity Resource Allocation Algorithm with Increasing Capacity in Cooperative OFDMA Systems

We investigated a conventional adaptive resource allocation scheme for the downlink of multi-hop orthogonal frequency division multiple access (OFDMA) systems. In addition, we formulated an optimization problem for an adaptive allocation for the subcarriers, paths, and power so that the system capacity could be maximized while minimum resources are guaranteed for each user. Since the optimization problem should be performed in real-time, a heuristic algorithm was recently proposed as a means of reducing the complexity. However, the implementation in cooperative OFDMA systems with radio frequency (RF) relays is not appropriate; moreover, the quantity of feedback is excessive for real-time operation, and the relay load balancing scheme is iterative and slightly inefficient. Thus, we propose an improved heuristic resource allocation algorithm that performs better than the conventional scheme. The proposed algorithm is suitable for cooperative OFDMA systems with RF relays; furthermore, it can reduce the complexity and increase the capacity.