A Novel Information and Energy Cooperation Transmission Scheme in Cognitive Spectrum Sharing-Based D2D Communication Systems

Abstract

Spectrum efficiency and energy efficiency are two critical issues in designing wireless communication networks. In this paper, we consider cognitive spectrum sharing-based cooperation between a single-antenna primary system and a multi-antenna wireless-powered device-to-device (D2D) communication system. A novel joint time division and power splitting-based three-phase information and energy cooperation transmission scheme are proposed for cognitive spectrum sharing-based D2D communication system. In the proposed scheme, the cognitive D2D transceiver pair adopts the power splitting technique to receive information and energy simultaneously from the primary transmitter (PT) in the first phase. Then, they utilize the beamforming technique and the harvested energy as half-duplex (HD) relays to jointly forward the primary user (PU) signal in the second phase. Eventually, in the third phase, they can communicate directly with each other by using the licensed spectrum and their remaining energy. We focus on the design of time division ratios, power splitting ratios, and beamforming vectors, with the objective to maximize the data rate of the cognitive D2D communication system, subject to the quality of service (QoS) requirement of the primary system, and the cognitive D2D communication system's minimum energy harvesting requirements and maximum power consumption constraints. The simulation results demonstrate that our proposed scheme is the best and significantly improves the average data rate of the cognitive D2D communication system under different PU target rate requirements or PT rated transmit power. Furthermore, a large number of simulations are demonstrated to verify the feasibility and effectiveness of the proposed scheme.