Heterogeneous Statistical-Delay QoS and Security Provisioning for D2D Underlay Cellular Networks

Device-to-Device (D2D) communication has been regarded as a promising technology in the future wireless networks. Due to the co-channel interference in D2D underlaying structure, it needs to guarantee the Quality-of-Service (QoS) requirements for both cellular users (CUEs) and D2D users. Moreover, there is also the information security problem in D2D communication systems. To solve the aforementioned issues, we in this paper employ the theory of statistical queueing analysis provide heterogeneous statistical-delay QoS guarantees and statistical delay-sensitive security protection for D2D communications underlay cellular networks. Based on the above work, we formulate the nonconvex optimization problem which aims at maximizing the sum effective capacity for CUEs and D2D users subject to D2D users' statistical delay-sensitive secrecy constraint as well as CUEs and D2D users' peak and average transmit power constraints. By using the convex approximation technique, we convert the original nonconvex problem to the equivalent convex problem and obtain the optimal power allocation scheme via the Lagrangian method. Simulation results are also provided to demonstrate the impact of diverse QoS demands and distinct security requirements on the sum effective capacity as well as the advantage of our proposed power allocation strategy over the CUE-based constant power scheme and the fixed power allocation policy.