Enhancing security in multicasting through correlated Nakagami-[formula omitted] fading channels with opportunistic relaying

Abstract

We consider a confidential wireless multicasting scenario in which a base station sends a common stream of information to a group of U users via K relays. V eavesdroppers are trying to decode that confidential information. We are interested to protect the decoding of that information and to see, how the opportunistic relaying can be used to enhance the level of security reducing the effect of correlations. We derive the closed-form analytical expressions for the probability of non-zero secrecy multicast capacity and the secure outage probability for multicasting in terms of the best relaying, and the correlation coefficients of constant, exponential and arbitrary correlations. Our results show that all the correlations are enemy of wireless security in multicasting and the impact of constant correlation is more significant than the exponential and arbitrary correlations. Although the performance of confidential wireless multicasting scenario decreases with the number of multicast users and due to the effect of correlations but this performance can be improved to an original one using the well known opportunistic relaying technique instead of increasing transmit signal power. Since all the relays compete to be the best relay, hence the trade off between the number of relays and multicast users has been established to maintain the acceptable security level reducing the effect of correlations. Finally, analytical results are verified via Monte-Carlo simulation.