Performance tradeoff in two-zone based wireless powered communication networks

In this paper we study two-zone based wireless powered communication networks (WPCNs) to overcome doubly near-far problem which causes a severe range discrimination. In the two-zone based WPCNs, near users in the inner region (Region 1) from the hybrid access point (H-AP) help far users in the outer region (Region 2) to relay their information to the H-AP in the uplink. We define the minimum energy harvested in the downlink for information transmission of near users in Region 1, and then propose an algorithm to determine a proper boundary for the greedy algorithm being used for relay pairing. The convex optimization technique is used to maximize the throughput of two-zone based WPCNs, whose performance, in terms of throughput and fairness, is compared with those with sum-throughput and common-throughput maximization techniques operated by the harvest-then-transmit protocol.