Joint Design of Power Control and Fronthaul Quantization Strategies for C-RAN and D2D Coexisting System

This work studies the uplink of a cloud radio access network (C-RAN) coexisting with a set of in-band device-to-device (D2D) communication links. In the system, the radio access communication from the user equipments (UEs), served by the C-RAN system, to the remote radio heads (RRHs) and the D2D communications take place at the same frequency band so that they interfere with each other while degrading the overall spectral efficiency performance. To mitigate this impact, the joint design of C-RAN uplink power control, D2D transmit power control as well as fronthaul quantization strategies is tackled with the goal of maximizing the sum-rate of all the UEs of the C-RAN and D2D communication systems. For the fronthaul quantization, both the Gaussian test channel and uniform scalar quantization approaches are considered. An iterative algorithm is derived based on the concave convex procedure (CCCP) approach to find an efficient solution, and numerical results are provided to examine the advantages of the proposed joint design as compared to the conventional separate optimization algorithms.