Performance Analysis of Multi-Antenna CR System with Beamforming Under Various Traffic Scenarios

Beamforming technology can enhance the throughput of a multi-antenna secondary user (SU) system. However, its performance depends on the accuracy of channel estimation (CE) that is influenced by CE duration. In this work, we present a three-phase transmission approach for a multi-antenna SU, where, in the first phase, the SU performs spectrum sensing, thereafter, the channel is estimated in the second phase followed by the data is transmitted using beamforming in the third phase. Consequently, based on it, we define a frame structure and closed-form expressions for SU's average throughput as well as interference energy received at the primary user's (PU's) receiver are derived. Numerical results validate the analysis and provide insights on the impact of frame duration and CE duration on SU's average throughput. Lastly, we investigate the throughput-interference tradeoff problem numerically with different values of CE duration.