  Reconfigurable Intelligent Surface (RIS) has becoming a useful tool in future
wireless communication systems for close-distance communication network. This
paper we use Reconfigurable Intelligent Surface (RIS) for downlink multi-user
communication designed to improve energy collection performance while
satisfying wireless information and Power Transfer (WIPT). The designed system
consists of an IRS-assisted system consists of a multi-antenna assisted base
station (BS) and two opposite multi-antenna assisted information receiver
cooperated (RIS) as energy receiver (ERs) that meets energy collection
requirements. Based on the electromagnetic property of Reconfigurable
Intelligent Surface (RIS), like two mirrors that are opposite each other,
setting two Reconfigurable Intelligent Surface (RIS) attached to the city
buildings to reflect the sending signals. The transmitting precoding of the
Multi-antenna Auxiliary Base Station (BS) and the angular phase transfer matrix
of the multi-antenna Auxiliary Information Receiver (IRs) need to be optimized
together to maximize the energy harvesting of IoT devices for energy efficiency
(EE) of the IRs system and to provide users with the efficiency of the received
signal. In order to solve the joint optimization problem effectively, we turn
the non-convex maximize problem into the equivalent formal error method based
on the mean square, and finally use the iterative algorithm for optimization.
As for algorithm, we respectively use MSE method, semidefinite relaxation
techniques to simplify transmitting beamforming matrix and the matrix phase
shift. Through the observation of simulation data, it can be concluded that the
performance optimization method of SDR based on RIS is effective.
