BD precoding schemes for cognitive MIMO system

This paper focuses on pre-coding schemes for the downlink of multiple user multi-input multi-output (MU-MIMO) system in cognitive radio (CR) network. The spectrum band can be utilized by allowing a number of cognitive users to coexist with primary users (PUs) through a pre-coding scheme. The capacity problems maximize the sum rate of CUs subject to the interference constraint for PUs and total transmitted power constraint can be solved with high complexity. To simplify the problem, this paper presents two suboptimal pre-coding schemes that pre-cancel the co-channel interference to PUs as well as mitigate interference between cognitive users (CUs). Simulation results show that the two suboptimal algorithms are able to achieve high sum rate throughput with low complexity.