National Chiao Tung University
The authors propose an optimal and a suboptimal resource allocation algorithms for sum rate maximization in an MISOOFDMA based cognitive radio network subject to a primary user outage constraint. By converting the outage constraint into user and subcarrier dependent peak power constraints, they obtain the optimal joint subcarrier assignment and power allocation solution by applying Lagrange dual-decomposition method. They also propose a low-complexity, fast-convergent suboptimal algorithm which uses an opportunistic channel gain-to-noise ratio based subcarrier assignment and an efficient constrained power allocation scheme. The optimality of the latter power allocation scheme is verified as well.