Cooperative Relaying Network Under SWIPT MIMO System

Abstract

Energy harvesting (EH) using simultaneous wireless information and power transfer (SWIPT) is an attractive solution in the context of enhancing the battery life of wireless devices for entirely reliable communication systems. Strong signal power can increase the power transfer. However, it also creates more interference in transmitting information, causing the realization of the SWIPT as a challenging problem. In this paper, SWIPT with multi-input-multi-output (MIMO) is considered for two users based on the precoding design. The source node (SN) will send the information and energy concurrently to the relay node (RN) in the first time phase within the SWIPT framework. Then the RN will reassemble the received signal and self-signal based on the decode and forward (DF) relaying protocol in the second time phase. Our target is to increase the EH at the RN under the data rate constraint of the SN and to maximize the data rate and downlink signal-to-interference-plus-noise-ratio (SINR) of the secondary user under the conditions to satisfy the quality of service (QoS) of the first user. Semidefinite relaxation (SDR) and Charnes-cooper transformation techniques are used to solve the nonconvex optimization problem. To support both the optimization problems CVX is premeditated, which is an efficient tool to solve convex and semidefinite programming (SDP) problems.