Achievable Rate Analysis of Intelligent Omni-Surface Assisted NOMA Holographic MIMO Systems
Qingchao Li, Mohammed El-Hajjar, Yanshi Sun, Ibrahim Hemadeh, Yingming Tsai, Arman Shojaeifard, Lajos Hanzo
TL;DR
The paper tackles enabling high spectral efficiency in IOS-assisted holographic MIMO downlinks with 360° coverage under practical hardware impairments. It develops a NOMA scheme with SIC and derives a moment-matching based ergodic-rate lower bound that accounts for HWIs, complemented by asymptotic analyses for infinite IOS elements and continuous apertures. Key findings show that NOMA outperforms OMA, but HWIs cause rate saturation at high SNR, while increasing IOS size or moving toward a continuous aperture yields bounded but improved performance under realistic conditions. The results provide design insights for IOS-based HMIMO systems and quantify the impact of HWIs on achievable rates in near-field/far-field channel fusion scenarios.
Abstract
An intelligent omni-surface (IOS) assisted holographic multiple-input and multiple-output architecture is conceived for $360^\circ$ full-space coverage at a low energy consumption. The theoretical ergodic rate lower bound of our non-orthogonal multiple access (NOMA) scheme is derived based on the moment matching approximation method, while considering the signal distortion at transceivers imposed by hardware impairments (HWIs). Furthermore, the asymptotically ergodic rate lower bound is derived both for an infinite number of IOS elements and for continuous aperture surfaces. Both the theoretical analysis and the simulation results show that the achievable rate of the NOMA scheme is higher than that of its orthogonal multiple access counterpart. Furthermore, owing to the HWIs at the transceivers, the achievable rate saturates at high signal-to-noise ratio region, instead of reaching its theoretical maximum.