Secure transmission via jamming in cognitive radio networks with possion spatially distributed eavesdroppers

This paper studies the physical layer security (PLS) in an underlay cognitive radio (CR) network. Under an interference constraint set by the primary user, we propose a secure transmission scheme from a secondary source to a secondary destination in the presence of spatially random eavesdroppers, the distribution of which is modeled as a homogeneous Possion point process (PPP). In addition to transmitting the message signal, the secondary source is allowed to use part of its power to transmit jamming signals in order to interfere the eavesdroppers. Assuming that the secondary destination has the knowledge of the jamming signals, we derive the closed-form expression for the connection outage probability and an easy-to-compute expression for the secrecy outage probability to characterize the reliability and the security performance, respectively. Moreover, we determine the optimal power allocation factor and wiretap code rates which maximize the secrecy throughput of the wiretap channel under secrecy outage probability constraint.