Bit Allocation for Increased Power Efficiency in 5G Receivers with Variable-Resolution ADCs

TL;DR

This paper proposes a variable-resolution ADC approach for 5G receivers that adaptively allocates bits based on signal strength, significantly reducing power consumption while maintaining performance.

Contribution

It introduces a novel ADC resolution optimization method for fully digital 5G receivers, enabling power savings through adaptive bit allocation per antenna.

Findings

Achieves 20-80% power savings compared to fixed low-bit ADCs.

Adaptive resolution improves efficiency depending on link SNR.

Demonstrates effectiveness in uplink scenarios with variable incoming signals.

Abstract

In future high-capacity wireless systems based on mmWave or massive multiple input multiple output (MIMO), the power consumption of receiver Analog to Digital Converters (ADC) is a concern. Although hybrid or analog systems with fewer ADCs have been proposed, fully digital receivers with many lower resolution ADCs (and lower power) may be a more versatile solution. In this paper, focusing on an uplink scenario, we propose to take the optimization of ADC resolution one step further by enabling variable resolutions in the ADCs that sample the signal received at each antenna. This allows to give more bits to the antennas that capture the strongest incoming signal and fewer bits to the antennas that capture little signal energy and mostly noise. Simulation results show that, depending on the unquantized link SNR, a power saving in the order of 20-80% can be obtained by our variable resolution proposal in comparison with a reference fully digital receiver with a fixed low number of bits in all its ADCs.