Optimal Power and Density Allocation of D2D Communication under Heterogeneous Networks on Multi-Bands with Outage Constraints

This paper analyzes the optimal power and density allocation for D2D (Device-to-Device) communication in heterogeneous networks on multi-bands with target of maximizing D2D achievable transmission capacity. The heterogeneous networks contain one or several cellular systems, and D2D communication shares uplink resources with them. By utilizing stochastic geometry, the problem is formed as sum capacity optimization for D2D network with constraints that guarantee outage probabilities of both cellular and D2D transmissions. The original problem is non- convex but we find the D2D transmission capacity has a remarkable property: it is sectional continuous with limited discontinuous point in the feasible region of power and density allocation and the maximum capacity is reached on the critical point. Based on this, we propose a algorithm as follows: first we figure out all of critical points as a candidate set and then obtain the optimal solution from them. The numerical results demonstrate the effectiveness of the algorithm and it shows that optimal parameters of D2D transmission is affected by outage constraints as well as the interference from cellular systems.