Security Provisioning for Non-Orthogonal Multiple Access Networks With Limited Feedback

In this letter, we investigate the information security problem for non-orthogonal multiple access (NOMA) networks against an external eavesdropper. Considering the overhead of the channel state information (CSI) feedback, we utilize the quantized CSI during the secure NOMA transmission, and derive the secrecy rate for each receiver by adopting the successive interference cancellation. In order to optimally allocate the transmit power, an optimization problem is formulated such that the minimum secrecy rate of the receivers is maximized. For the proposed scheme, we also analyze the secrecy outage and transmission outage probabilities, and their closed-form expressions are derived. In addition, the security-reliability tradeoff is analyzed. Numerical results are demonstrated to verify the analytical results.