Zero Forcing Algorithms for a Multi-User Cognitive Wireless Communication System
Fazhong Liu, Dongxu Wang, Chong Li, Mingming Li · ASME Press eBooks · 2011
Though cognitive radio (CR) technology has been presented as one useful technology to enhance the spectrum efficiency, co-channel interference from the cognitive user (CU) to primary user (PU) can not be ignored. In order to obtain the maximal throughput, PUs should find out a new technique to derive good performance. In this paper, we present precoding schemes for the downlink of a MIMO system with the coexistence between a set of primary users and a cognitive user. The effective Zero-Forcing Beamforming (ZFB) algorithm is proposed to maximize the sum rate of PUs and satisfy the co-channel interference constraint from the CU to PUs, the total transmitted power constraint for primary access point (PAP) as well as the Signal to Interference and Noise Ratio of the CU is bigger than a given threshold γ . Simulation results show that our suboptimal algorithm is able to achieve high sum rate throughput with low complexity.