Spectral Efficiency of One-Bit Sigma-Delta Massive MIMO

TL;DR

This paper investigates the uplink spectral efficiency of massive MIMO systems using a novel one-bit Sigma-Delta spatial sampling scheme, which shapes quantization noise to improve performance.

Contribution

It introduces a new spatial Sigma-Delta sampling method for massive MIMO, with an analytical model and performance analysis demonstrating significant gains.

Findings

Spatial Sigma-Delta reduces quantization noise in the sector of interest.

Theoretical spectral efficiency matches simulation results.

Performance gains are evident for both MRC and zero-forcing receivers.

Abstract

We examine the uplink spectral efficiency of a massive MIMO base station employing a one-bit Sigma-Delta sampling scheme implemented in the spatial rather than the temporal domain. Using spatial rather than temporal oversampling, and feedback of the quantization error between adjacent antennas, the method shapes the spatial spectrum of the quantization noise away from an angular sector where the signals of interest are assumed to lie. It is shown that, while a direct Bussgang analysis of the Sigma-Delta approach is not suitable, an alternative equivalent linear model can be formulated to facilitate an analysis of the system performance. The theoretical properties of the spatial quantization noise power spectrum are derived for the Sigma-Delta array, as well as an expression for the spectral efficiency of maximum ratio combining (MRC). Simulations verify the theoretical results and illustrate the significant performance gains offered by the Sigma-Delta approach for both MRC and zero-forcing receivers.