5G Millimeter Wave Cellular System Capacity with Fully Digital Beamforming
Abstract
Due to heavy reliance of millimeter-wave (mmWave) wireless systems on directional links, Beamforming (BF) with high-dimensional arrays is essential for cellular systems in these frequencies. How to perform the array processing in a power efficient manner is a fundamental challenge. Analog and hybrid BF require fewer analog-to-digital converters (ADCs), but can only communicate in a small number of directions at a time,limiting directional search, spatial multiplexing and control signaling. Digital BF enables flexible spatial processing, but must be operated at a low quantization resolution to stay within reasonable power levels. This paper presents a simple additive white Gaussian noise (AWGN) model to assess the effect of low resolution quantization of cellular system capacity. Simulations with this model reveal that at moderate resolutions (3-4 bits per ADC), there is negligible loss in downlink cellular capacity from quantization. In essence, the low-resolution ADCs limit the high SNR, where cellular systems typically do not operate. The findings suggest that low-resolution fully digital BF architectures can be power efficient, offer greatly enhanced control plane functionality and comparable data plane performance to analog BF.
Cite
@article{arxiv.1711.02586,
title = {5G Millimeter Wave Cellular System Capacity with Fully Digital Beamforming},
author = {Sourjya Dutta and C. Nicolas Barati and Aditya Dhananjay and Sundeep Rangan},
journal= {arXiv preprint arXiv:1711.02586},
year = {2018}
}
Comments
To appear in the Proceedings of the 51st Asilomar Conference on Signals, Systems, and Computers, 2017