Conjoint Routing and Resource Allocation in OFDMA-Based D2D Wireless Networks

In this paper, we develop a highly efficient two-tier technique for jointly optimizing the routes, the subcarrier schedules, the time-shares, and the power allocations in device-to-device communication networks with thousands of randomly dropped wireless nodes. The network is first divided into a set of non-overlapping sub-networks, each with its own regional controller. The role of such a controller is to optimize the sub-network within its region and to act as an interface between nodes communicating across regions. The first tier of the proposed technique uses a novel approach for splitting a set of highly non-convex constraints into effectively two sets of convex ones and optimization proceeds by using two loops: an outer loop for iterating between the power allocations and the subcarrier schedules, and an inner loop for iterating between the two sides of the split constraints. In the second tier, a technique analogous to the one used in the first tier is applied to the network composed of the regional controllers. Optimization in this tier is performed by a global controller. The proposed technique is capable of efficiently optimizing networks with tens of thousands of nodes and with significantly better performance than existing joint design techniques, which can only optimize networks with a few tens of nodes.