Cognitive Radio Enhancement using Massive MIMO System

Abstract

In this chapter, the precoder design of a M-MIMO Overlay CR system is introduced. The optimization problem of a two-stage precoder design is formulated to serve both the SUs and PUs. The design problem is able to cancel the interference on SUs due to PUs relaying, decrease the number of constraints to become function of the number of antennas used for SUs transmission instead of the full array size. The proposed algorithm leads to an enhancement in the total sum data rate of the system compared to TAS algorithm, and maintains the achieved SUs sum rate, while the significant decrease in the computational time of the precoder optimization problem is still achieved. Simulation results demonstrate that the difference between the achieved capacity of both SUs plus PUs in case of the proposed TASD and the full array scenario is less than 3%, and the SUs sum rate is the same compared to TAS algorithm. On the other hand, the computational time of the optimization problem decreases by around 50%.