Sum Rate Maximization by Beamforming over Cognitive Radio Network

Abstract—An effort has been made to illustrate the performance comparison of the Rayleigh and Rician fading channel models by using MATLAB simulation in terms of Sum rate and signal to noise ratio (SNR). We have developed algorithms for the Rayleigh and Rician fading channels, which computes the Sum rate for the primary and the secondary user. Cognitive radio is regarded as one the most promising technology for supporting spectrum sharing which secondary (cognitive) users coexist with users in primary network whose radio band is licensed. Two conflicting challenges are how to maintain the interferences generated by the cognitive radio network to the primary network below an acceptable threshold level while maximizing the sum-rate of the cognitive radio network. Signaling is the major issue in Cognitive Network. We propose optimum beamforming algorithms to design beamforming vectors for cognitive networks to maximize the achievable rates, where primary and cognitive users share the same spectrum and are equipped with multiple antennas. The proposed technique does not require any changes in the existing environment between the primary and secondary user. The secondary user will be allowed to transmit concurrently to the primary user. Since the primary user is a licensed one it need not to have any knowledge about the resources utilized and performance of the secondary user and it transmits independently. Simulation results are given to evaluate the performances of the proposed methods in forms of SINR and sum-rates.