Adaptive tracking of optimal bit and power allocation for OFDM systems in time-varying channels

This paper presents an adaptive tracking algorithm for adaptively updating the bit and power allocation for OFDM transmission in a time-varying channel. The proposed algorithm utilities the previous bit allocation information for initialization, and then iteratively refines the allocation until it reaches the optimal solution. We prove a theorem which guarantees the convergence of the algorithm to the optimal solution. Through simulation, we find that the proposed algorithm converges quickly in just a few iterations when the variation in the channel is small. When the channel changes rapidly the adaptive tracking algorithm is still computationally much more efficient than existing algorithms which solve the problem from scratch.