Energy-Efficient Resource Allocation for 5G Full-Duplex Enabled Device-to-Device Communication

Full-duplex (FD) transmission and device-to-device (D2D) communication underlaying cellular networks are viewed as key components in the fifth generation (5G) systems, and their benefit can be magnified if they are effectively combined together. However, the self- interference at FD-enabled mobile terminals and the mutual interference between D2D links and cellular links are inevitable due to spectral reuse. Furthermore, there is also a need to strike a balance between spectral efficiency and energy conservation. Therefore, we aim to optimize energy efficiency for FD D2D underlaying system by incorporating power control (PC) and channel assignment (CA) under additional quality-of-service requirements of the existing cellular links. With the property of fractional programming, we transfer the original problem into solving a sequence of parametric programs in subtractive form. Besides, for each of the above parametric programs, it can be decomposed into the PC subproblem and the CA subproblem. Moreover, the former turns out to be a difference-of-concave (D-C) programming, which can be well addressed by the sequential convex optimization technique. Based on the above optimum, the latter reduces to the assignment problem, which can be perfectly resolved by Hungary algorithm. In addition, we discuss the time complexity and implementation issue of our scheme. Thanks to the simulations, we observe the benefit of FD D2D underlaying system compared to its half-duplex counterpart and elucidate the efficacy of our scheme.