Beyond Limitations of 5G with RIS: Field Trial in a Commercial Network, Recent Advances, and Future Directions

Reconfigurable intelligent surface (RIS) attracts considerable attention as a promising solution to enhance coverage and energy efficiency in 5G communication. In this paper, we validate the performance of RIS in a 5G commercial FR2 band network, proving that it can overcome the coverage limitations of 5G. We first introduce the appropriate hardware design of RIS in mm-wave and explain its performance, including a massive structure, a wide beam coverage, and its ability to transmit wideband signals without distortion. Then, we describe the topology for field trial construction using RIS-assisted ray-tracing to increase the coverage enhancement performance of RIS in indoor scenarios where coverage prediction is challenging. Finally, we confirm the improvement in indoor coverage and capacity in a commercial network, as demonstrated by an increase in throughput of up to 227.69 percent. To the best of our knowledge, our survey represents the first indoor testbed that evaluates throughput, as well as reference signal received power (RSRP) and signal-tointerference plus noise ratio (SINR) within a commercial FR2 band network. We conclude with some future challenges and the corresponding future research directions.