Weighted Sum Rate Optimization for Cognitive Radio MIMO Broadcast Channels

In this paper, we consider a cognitive radio (CR) network in which the unlicensed (secondary) users are allowed to concurrently access the spectrum allocated to the licensed (primary) users provided that their interference to the primary users (PUs) satisfies certain constraints. We study a weighted sum rate maximization problem for the secondary user (SU) multiple input multiple output (MIMO) broadcast channel (BC), in which the SUs have not only the sum power constraint but also interference constraints. We transform this multi-constraint maximization problem into its equivalent form, which involves a single constraint with multiple auxiliary variables. Fixing these multiple auxiliary variables, we propose a duality result for the equivalent problem. Our duality result can solve the optimization problem for MIMO-BC with multiple linear constraints, and thus can be viewed as a generalization of the conventional results, which rely crucially on a single sum power constraint. Furthermo...

• Type: Journal
• Year: 2008
• Where: CORR
• Authors: Lan Zhang, Yan Xin, Ying-Chang Liang
• Keywords: CORR 2008, Education, Maximization Problem, Multiple Auxiliary Variables, Sum Power Constraint