Optimization of Simultaneous Wireless Information and Power Transfer in Cloud Radio Access Networks

In this paper, we focus on optimization of simultaneous wireless information and power transfer (SWIPT) in uplink cloud radio access network (C-RAN). The key idea is to design transceiver architecture and implement the SWIPT strategy at remote radio heads (RRHs). The minimum mean-square-error (MMSE) is considered as the performance metrics with transmit power constraint and energy constraint. Toward the goal of MMSE, the precoders and the detectors are iteratively updated in proposed scheme. However, because of the energy constraint, the precoding optimization problem with a specified detection matrix become non-convex. To solve this problem, a new precoding design based on the Lagrangian dual relaxation (LDR) is developed. Meanwhile, conditions to make sure the optimization problem has its physical interpretation and LDR become convex are determined. Finally, simulation results demonstrate that the proposed transceiver design can significantly improve the system performance.