Throughput maximization in wireless powered communication networks with minimum node throughput requirement

This paper considers wireless powered communication network consisting of one hybrid access point and a set of one-hop nodes. Hybrid access point conducts wireless energy transfer (WET) in the downlink and nodes conduct wireless information transmissions (WITs) in the uplink based on the time division multiple access (TDMA) mode. Specifically, for the scenario where each node has its own minimum throughput requirement and different nodes' data have different levels of utility, we aim to achieve the minimum node throughput constrained weighted sum throughput maximization (MT-WSTM) by jointly optimizing the time allocations of the WET and the WITs. First, we formulate the MT-WSTM problem as a nonlinear optimization problem and further transform it into a more tractable form. Then, we prove the MT-WSTM problem is convex and develop an efficient algorithm utilizing the dual decomposition technique to obtain the optimal solution of this problem. Compared with two schemes which use the optimal WET time and allocate the surplus WIT time evenly to all nodes and solely to the best node, respectively, the weighted sum throughput of the MT-WSTM scheme is obviously larger in both homogeneous and heterogeneous scenarios.