Adaptive Resource Allocation Based on Channel Information in Multihop OFDM Systems

In this paper, we investigate the adaptive resource allocation problem in multiuser multihop OFDM systems. Assuming that base station(BS) knows all channel information, we formulate capacity maximization problem(CMP) and fairness constrained capacity maximization problem(FCMP) for adaptive resource allocation. The CMP considers joint subchannel, power and path allocation problem for maximizing the system capacity, while the FCMP considers the same problem with guaranteeing a minimum number of subchannels for each user. The proposed optimization problems are productive, because BS can allocate the subchannel, power and routing path to MSs by solving one optimization problem. Since these optimizations should be performed in real time, we propose two efficient heuristic algorithms, one of which considers CMP and the other considers FCMP. In the heuristic algorithms, we separate the optimization problem into three steps, namely subchannel allocation, load balancing, and power distribution to reduce computational complexity. The proposed heuristic algorithms are simple in that the iterative computations are removed, and accurate in that two heuristic algorithms achieve a similar performance compared with optimum solution.