Secrecy performance comparison of diversity combining techniques in wireless multicast networks

Multipath fading significantly affects the reliability and secrecy performance of wireless multicast networks, especially in Nakagami-0.5 fading environments, which characterize highly scattered and deep fading scenarios. Among various countermeasures, diversity combining techniques have been widely recognized as effective solutions for mitigating fading and enhancing secrecy performance, making them particularly suitable for multicast networks. This paper presents a comparative study of Selection Combining and Maximal Ratio Combining schemes for improving the physical layer security performance of multicast networks operating over Nakagami-0.5 fading channels in the presence of multiple eavesdroppers. Performance analysis is carried out through mathematical modeling of key secrecy metrics, including probability of non-zero secrecy capacity and secrecy outage probability. The results reveal that the detrimental impact of multipath fading can be significantly mitigated by employing diversity combining techniques at the receiver. However, Maximal Ratio Combining consistently outperforms Selection Combining due to its optimal signal to noise ratio maximization capability, providing higher secrecy capacity and lower outage probability, although at the cost of increased implementation complexity. Conversely, Selection Combining offers a simpler and energy-efficient solution with moderate performance improvements. Analytical findings are validated through Monte Carlo simulations, confirming the accuracy and practical relevance of the proposed model.