Rate-Splitting Multiple Access for Uplink Massive MIMO With Electromagnetic Exposure Constraints

Abstract

Over the past few years, the prevalence of wireless devices has become one of the essential sources of electromagnetic (EM) radiation to the public. Facing with the swift development of wireless communications, people are skeptical about the risks of long-term exposure to EM radiation. As EM exposure is required to be restricted at user terminals, it is inefficient to blindly decrease the transmit power, which leads to limited spectral efficiency and energy efficiency (EE). Recently, rate-splitting multiple access (RSMA) has been proposed as an effective way to provide higher wireless transmission performance, which is a promising technology for future wireless communications. To this end, we propose using RSMA to increase the EE of massive MIMO uplink while limiting the EM exposure of users. In particularly, we investigate the optimization of the transmit covariance matrices and decoding order using statistical channel state information (CSI). The problem is formulated as non-convex mixed integer program, which is in general difficult to handle. We first propose a modified water-filling scheme to obtain the transmit covariance matrices with fixed decoding order. Then, a greedy approach is proposed to obtain the decoding permutation. Numerical results verify the effectiveness of the proposed EM exposure-aware EE maximization scheme for uplink RSMA.

Unveiling Passive and Active EMF Exposure in Large-Scale Cellular Networks

“…For EMF-aware cellular system design, a resource allocation scheme was developed in [19] to minimize the EMF exposure. Rate-splitting multiple access (RSMA)-based with EMF constraints was investigated in [20] where the uplink energy efficiency is enhanced while limiting the EMF exposure under a certain level. A reconfigurable intelligent surface (RIS)-assisted network was analyzed in [21] to minimize the EMF exposure of users while maintaining a minimum target quality of service.…”

Max-Min Fairness of Rate-Splitting Multiple Access With Finite Blocklength Communications

“…Moreover, RSMA with network slicing has been stated to provide a more flexible decoding order and a larger achievable rate region than Orthogonal Multiple Access (OMA) and NOMA [25]. Uplink MIMO RSMA with electromagnetic exposure constraints has been studied in [26], demonstrating the significant gain over NOMA and SDMA in terms of sum-rate.…”