Secure transmission using optimal antenna selection for MIMO underlay CRN with multiple primary users

Abstract

The authors present a method of utilisation diversity combining to improve the secrecy performance of an underlay cognitive radio network (CRN) with single or multiple primary users (PUs) over Rayleigh fading environment. They consider a practical scenario where a secondary transmitter (STX), a secondary receiver (SRX), and an eavesdropper (Eve) receiver are equipped with multiple antennas while all PUs are employed with a single antenna. The confidential information is transmitted from STX to SRX under the malicious attempt of an Eve. Generalised selection combining is applied at the SRX, and maximal ratio combining is adopted at the Eve. Depending upon the availability of the global channel state information of the main and eavesdropper's channels at STX, the secrecy outage performances of optimal antenna selection and sub-optimal antenna selection schemes have been examined. They derive a closed-form expression for the exact secrecy outage probability, asymptotic secrecy outage probability and intercept probability in a Rayleigh fading environment. Numerical results show that secrecy performance of the network improves with increasing the transmitting antennas while it degrades with increasing the number of PUs. © The Institution of Engineering and Technology 2019.