Secrecy Performance of Cognitive Radio Networks Using Arbitrary Transmit Antenna Selection and Threshold- Based MRC

This paper postulates the secrecy performance of an underlay cognitive radio network where legitimate receiver combines signal replicas per threshold-based maximal ratio combining (MRC), and secondary transmitter selects a single antenna based on combined signal to noise ratio at a legitimate receiver in the presence of multiple eavesdroppers. Output threshold-based MRC scheme is the variant of the MRC scheme which saves processing power at the legitimate receiver and also provides considerable improvement in secrecy performance. For this scenario, we derive new closed-form expressions for exact secrecy outage probability. Numerical results show that output- threshold MRC technique leads to less power consumption while providing the same performance as conventional MRC.