Efficient branch and bound algorithms for prototype filter optimization in OQAM-OFDM systems.

In this paper, we address the prototype filter optimization problem in the offset quadrature amplitude modulation-based orthogonal frequency division multiplexing system and propose a series of efficient branch and bound (BB)-based methods to greatly reduce the convergence time of the optimization problem. Specifically, we first propose a constraint judge method to determine whether a subset has the possibility to obtain a feasible solution and remove the subsets that have no feasible solutions. Then, we propose a searching strategy to further decrease the number of iterations. Moreover, we propose an efficient convex relaxation method to reduce the calculation time of each iteration. Simulation results show that the proposed methods can guarantee the same global optimal solution as generated by the conventional α-based BB ( αBB) algorithm, and the BB algorithm combining the three proposed methods achieves much lower convergence time. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]