Relay-based harvest-then-transmit protocol for uplink cellular networks

We propose a relay-based harvest-then-transmit (HTT) protocol for time division multiple access uplink cellular networks. In the HTT protocol, the base stations transmit downlink wireless energy harvesting (DWEH) signals to users at the beginning of uplink time frame while the remaining time is used for uplink wireless information transfer (UWIT). Relay nodes are designed to independently broadcast energy harvesting signals for cell-edge users in the downlink while they relay information signals from cell-edge users to the base stations in the uplink. We jointly optimize DWEH and UWIT time of all users to maximize the total throughput of the system. Numerical results demonstrate that incorporation of relay nodes enhances the performance in terms of cell-edge user throughput, throughput fairness, and total network throughput.