Abstract: In this paper, we consider a joint beamforming, channel allocation in Multiple-Input Multiple-Output cognitive radio network (CRN). In this system, primary usersí (PUsí) spectrum can be reused by the secondary user transmitters (SUTXs) to maximize the spectrum utilization while the intra-user interference is minimized by implementing beamforming at each SU-TX. After formulating the joint optimization problem in MIMO (Multiple-Input Multiple-Output) we propose a solution which consists of two stages. In the first stage, a feasible solution for channel allocation and beamforming vectors is derived under SVD Algorithm and also by using Genetic Algorithm (GA). After that, in the second stage, two explicit searching algorithms, i.e., SVD Algorithm and Genetic Algorithm (GA) are proposed to determine the Throughput rate achievement. Simulation results show that beamforming, channel allocation with Genetic Algorithm (GA) can achieve close-to-optimal sum-rate while having a lower computational complexity compared with beamforming, channel allocation with Singular Value Decomposition (SVD) algorithm. Furthermore, our proposed allocation scheme has significant improvement in achievable sum-rate compared to the existing zero-forcing beamforming (ZFBF).

Keywords: MIMO System,Cognitive radio network (CRN), beamforming, Singular Value Decomposition Algorithm, Genetic algorithm.