Performance Analysis of a MIMO Cognitive Cooperative Radio Network with Multiple AF Relays

Abstract: With the rapid growth of wireless communications, the demand for the various multimedia services is increasing day by day leading to a deficit in the frequency spectrum resources. To overcome this problem, the concept of cognitive radio technology has been proposed which allows the unlicensed secondary user (SU) to access the licensed spectrum of the primary user (PU), thus improving the spectrum utilization. Cooperative communications is another emerging technology which is capable of overcoming many limitations in wireless systems by increasing reliability and coverage. The transmit and receive diversity techniques such as orthogonal space–time block codes (OSTBCs) and selection combining (SC) in multiple-input multiple-output (MIMO) cognitive amplify and forward relay networks help to reduce the effects of fading, increase reliability and extend radio coverage.   In this thesis, we consider a MIMO cognitive cooperative radio network (CCRN) with multiple relays. The protocol used at the relays is an amplify and forward protocol. At the receiver, the SC technique is applied to combine the signals. Analytical expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the signal-to-noise ratio (SNR) are derived. On this basis, the performance in terms of outage probability is obtained. Mathematica has been used to generate numerical results from the analytical expressions. The system model is simulated in MATLAB to verify the numerical results. The performance analysis of the system model is hence done in terms of outage probability.