An iterative reweighted minimization framework for joint channel and power allocation in the OFDMA system

We consider the joint channel and power allocation problem for the OFDMA system. The problem is to find a joint channel and power allocation strategy to minimize the total transmission power subject to quality of service constraints and the OFDMA constraint (i.e, at most one user is allowed to access each channel). Since the problem is generally NP-hard, the idea of the existing algorithms is to heuristically allocate the channel and power resources separately. In this paper, we propose a novel iterative reweighted minimization framework based on an effective relaxation, which is beneficial by reformulating the combinatorial OFDMA constraint as an equivalent continuous optimization problem. The proposed framework simultaneously allocates the channel and power resources, and thus is sharply different from the existing ones. Simulation results show the proposed iterative reweighted minimization methods significantly outperform the existing algorithms.