Monotonic Optimization for Power Control of D2D Underlay with Partial CSI

This paper studies power allocation optimization for D2D-underlay enabled cellular systems where only channel fading information is known at the eNB. Unlike instantaneous channel state information (CSI) assumed in many existing works, statistical (partial) CSI is more readily available from long term practical measurement. Within the partial CSI framework, we study the problem of maximizing ergodic weighted D2D sum rate under cellular outage constraints. While the ergodic sum rate maximization problem is NP-hard for interference channels, the outage constraints make the problem even more challenging. We propose a solution based on the framework of monotonic optimization (MO) by identifying the monotonicity in both rate and outage functions. We apply the branch-reduce-and-bound (BRB) algorithm to solve the MO problem and improve its numerical efficiency. We present simulation results to show the feasibility of proposed solution under various channel models.