BER Performance Analysis of Coarse Quantized Uplink Massive MIMO

TL;DR

This paper derives an analytical BER approximation for coarse quantized uplink massive MIMO systems with various quantization levels and modulation types, revealing the impact of quantization resolution and quantizer type on system performance.

Contribution

It provides a closed-form expression for BER in quantized massive MIMO with different quantization resolutions and quantizer types, validated by simulations.

Findings

Non-uniform quantizers yield tighter BER bounds than uniform ones.

Coarse quantization causes small BER degradation, mitigated by more antennas.

Performance degradation is minimal for 2-3 bits QPSK and 3-4 bits 16-QAM.

Abstract

Having lower quantization resolution, has been introduced in the literature, as a solution to reduce the power consumption of massive MIMO and millimeter wave MIMO systems. In this paper, we analyze bit error rate (BER) performance of quantized uplink massive MIMO employing a few-bit resolution ADCs. Considering Zero-Forcing (ZF) detection, we derive a closed-form quantized signal-to-interference-plus-noise ratio (SINR) to achieve an analytical BER approximation for coarse quantized M-QAM massive MIMO systems, by using a linear quantization model. The proposed expression is a function of quantization resolution in bits. We further numerically investigate the effects of different quantization levels, from 1-bit to 4-bits, on the BER of three modulation types of QPSK, 16-QAM, and 64-QAM. Uniform and non-uniform quantizers are employed in our simulation. Monte Carlo simulation results reveal that our approximate formula gives a tight upper bound for the BER performance of $b$-bit resolution quantized systems using non-uniform quantizers, whereas the use of uniform quantizers cause a lower performance for the same systems. We also found a small BER performance degradation in coarse quantized systems, for example 2-3 bits QPSK and 3-4 bits 16-QAM, compared to the full-precision (unquantized) case. However, this performance degradation can be compensated by increasing the number of antennas at the BS.