Sum-rate Maximization for RIS-assisted IoT.

Abstract—With the development of smart devices, Internet of Things(IoT) has requirements for high coverage, high reliability, and low power consumption for wireless communication systems. The emergence of reconfigurable intelligent surfaces(RIS) provides an achievable solution for further development of IoT. RIS consists of passive low-cost components, which can reshaping the wireless channel. Thus it can improve multi-stream transmission gain, enhance edge coverage and realize large-scale Device-to-Device communication. In this paper, we consider RIS-assisted multiple-input single-output(MISO) communication systems, and our goal is to maximize the sum-rate of all IoT receiving devices by jointly designing the beamforming of access points(AP) and the phase shift of RIS elements. For the non-convex problem form, we propose the Improved Elite Genetic Algorithm(IEGA) to obtain a smooth solution of the problem. Numerical results demonstrate the effectiveness of RIS and the proposed joint algorithm for the performance improvement of IoT wireless communication systems.We analyzed the impact of the deployment of RIS and the number of RIS elements on the sum-rate at the receiving devices, which facilitates the balance between the cost and benefit of increasing RIS elements in practical deployments.