Statistical analysis of a class of secure relay assisted cognitive radio networks

In this paper, the problem of communication security in an underlay wiretap cognitive radio network is addressed and statistically investigated. We rely on a simple dual-hop communication model of decode and forward relay assisted network. Regarding the interference from primary users, interference power and maximum transmit power constraints; this network is subjected to multiple eavesdropping attacks which employ a specific interception strategy. To confound this eavesdropping, proposed selection schemes are exploited that aim at maximizing the minimum of the dual secrecy rates in order to strengthen the physical layer security. Moreover, exact and asymptotic closed form expressions are derived for specific performance metrics over independent and identically distributed Rayleigh fading channels. At high signal to interference noise ratio (SINR), tangential system bounds are also derived and discussed. Monte Carlo simulation results emphasize our assumption. It is found out that at the full diversity of the system, any additional node that enters the cooperative eavesdropping system becomes significantly of no effect.