Resource Allocation for Secure Communication in Cooperative CR Networks

This paper investigates joint resource allocation to provide information security in a five nodes CRNS system, which includes a primary transmitter (PT), a primary receiver (PR), a secondary transmitter (ST), a secondary receiver (SR) and an eavesdropper (E). To ensure the security of the information, PT and PR are allowed to use part of power to transmit artificial noise to confuse the eavesdropper. PT firstly transmits signal containing secrecy information and artificial noise by using all power and bandwidth resources. Then ST as a trusted relay accesses to the licensed bandwidth and allocates a fraction of bandwidth resources to forward primary information in decode-and-forward (DF) mode. As a reward, it can utilize the remaining bandwidth to transmit its own information simultaneously. We study joint optimization of the bandwidth, time and power allocation to maximize the secondary rate while satisfying the secrecy transmission rate requirements of PR. Numerical results demonstrate that our strategy can realize win-win result.