Optimal Base Station Design with Limited Fronthaul: Massive Bandwidth or Massive MIMO?

TL;DR

This paper investigates the optimal design of base stations in 5G networks with limited fronthaul capacity, balancing the number of antennas, bandwidth, and quantization to maximize data rates.

Contribution

It provides an analytical framework for optimizing antenna count, bandwidth, and quantization under fronthaul constraints, highlighting the benefits of many low-resolution antennas.

Findings

Many antennas with low-resolution ADCs are optimal under fronthaul constraints.

The optimal bandwidth depends on system parameters and fronthaul capacity.

Numerical results offer design insights for cost-effective 5G base stations.

Abstract

To reach a cost-efficient 5G architecture, the use of remote radio heads connected through a fronthaul to baseband controllers is a promising solution. However, the fronthaul links must support high bit rates as 5G networks are projected to use wide bandwidths and many antennas. Upgrading all of the existing fronthaul connections would be cumbersome, while replacing the remote radio head and upgrading the software in the baseband controllers is relatively simple. In this paper, we consider the uplink and seek the answer to the question: If we have a fixed fronthaul capacity and can deploy any technology in the remote radio head, what is the optimal technology? In particular, we optimize the number of antennas, quantization bits and bandwidth to maximize the sum rate under a fronthaul capacity constraint. The analytical results suggest that operating with many antennas equipped with low-resolution analog-to-digital converters, while the interplay between number of antennas and bandwidth depends on various parameters. The numerical analysis provides further insights into the design of communication systems with limited fronthaul capacity.