Design and measurement of reconfigurable intelligent surface-aided millimeter-wave coverage enhancement with wide beam

To address the issue of weak signal coverage of the millimeter-wave in wireless communication Systems, the method for using the reconfigurable intelligent surface(RIS) to reflect wide beams is proposed, which enhances the signal strength in weak coverage areas. First, an RIS is introduced between the transmitter and receiver, with no direct line-of-sight path between them, to enhance the received signal strength in weak coverage areas. A general electromagnetic wave propagation model for RIS-aided millimeter-wave communication is established, with an analytical expression for the received signal power derived. Subsequently, based on different levels of prior information about the area, a general design framework for the reflection phase shift of RIS is proposed. For the optimization problem of discrete phase shifts of RIS, a heuristic algorithm is employed for efficient optimization. Simulation results demonstrate that the proposed algorithm can synthesize reflection beams with any width based on RIS. Additionally, further optimization based on specific information about the area shape can further improve the millimeter-wave signal coverage Performance in the target area. Finally, a radiation pattern measurement System and a RIS-based millimeter-wave communication pro to type System are set up. Measurement campaigns are conducted in the 35 GHz frequency band, yielding results that match those in the simulations. Radiation pattern measurement results in an anechoic chamber validate the effectiveness of the wide beam synthesis algorithm. In real-world signal coverage measurements, the signal coverage rate is improved from 1.5% to 90 % after deploying RIS and the proposed algorithm, as compared to the scenario without RIS. © 2024 Science Press. All rights reserved.