Abstract
Reconfigurable intelligent surfaces (RISs) consisting of multiple reflective elements are a promising technique to enhance communication quality as they can create favorable propagation conditions. In this letter, we characterize the fundamental relations between the number of reflective elements and the system sum-rate in RIS-assisted multi-user communications. It is known from previous works that the received signal-to-noise ratio (SNR) can linearly increase with the squared number of RIS reflective elements, but how many elements are sufficient to provide an acceptable system sum-rate still remains an open problem. To this end, we derive the asymptotic capacity with zero-forcing (ZF) precoding, and then analyze how many reflective elements are required so that the ratio of the system sum-rate to the capacity can exceed a predefined threshold. Numerical results verify our analysis.
| Original language | English (US) |
|---|---|
| Article number | 9352958 |
| Pages (from-to) | 1098-1102 |
| Number of pages | 5 |
| Journal | IEEE Wireless Communications Letters |
| Volume | 10 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2021 |
| Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Electrical and Electronic Engineering
- Control and Systems Engineering
Keywords
- Reconfigurable intelligent surface
- multi-user communications
- reflective elements