Low-Resolution DAC Beamforming for Energy-Efficient Massive MIMO

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Solution Overview

Problem

Existing 5G wireless communication systems face challenges in energy efficiency due to the high power consumption of digital-to-analog converters (DACs), especially in millimeter wave (mmWave) spectrum, where massive Multiple-Input and Multiple-Output (MIMO) systems struggle with digital massive MIMO deployment and hybrid beamforming techniques result in performance loss.

Innovation Solution

The implementation of low-resolution digital-to-analog converters (DACs) with signal processing algorithms and circuits that reduce the number of bits per sample and sampling rate, enabling all-digital beamforming and reducing power consumption, while maintaining key performance indicators such as throughput and signal quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-resolution DACs and high sampling rates are used in mmWave MIMO systems, then signal quality and throughput are improved, but power consumption increases significantly

Engineering Contradiction:

Improvesignal qualityVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the resolution parameter of DACs from traditional high-resolution (12-14 bits) to low-resolution (2-4 bits) while compensating through advanced signal processing algorithms that operate in the symbol domain, maintaining signal quality despite reduced per-sample precision

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of using high-resolution DACs for every sample, the system uses low-resolution DACs with excessive processing compensation, applying sophisticated digital signal processing and machine learning algorithms to recover the performance that would be lost through quantization

Inventive Principle:

Principle #16Partial or excessive action

2Productivity

If the number of transceiver chains and antennas is increased for massive MIMO, then spectral efficiency is improved, but device complexity and cost increase

Engineering Contradiction:

Improvespectral efficiencyVSAvoidnumber of transceiver chains

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the signal processing function by removing the digital-to-analog conversion function from each individual transceiver chain, centralizing the high-resolution conversion at the baseband unit while keeping only low-resolution converters at the antenna units, thereby reducing per-antenna complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The baseband unit performs multiple functions including high-resolution DAC conversion, digital beamforming, and signal processing for all antenna chains, while each antenna unit only performs simple low-resolution conversion and analog beamforming, creating a universal processing architecture

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Use of energy by moving object

If low-resolution DACs are used, then power consumption is reduced, but manufacturing precision and signal accuracy deteriorate

Engineering Contradiction:

Improvepower consumptionVSAvoidsignal accuracy

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent replaces the traditional hardware-based high-resolution DAC approach with a software/algorithm-based correction system that uses machine learning models and digital signal processing to compensate for the imperfections introduced by low-resolution quantization

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system implements feedback mechanisms where received signals are processed through machine learning algorithms that continuously adapt and refine the signal reconstruction, using error feedback from the low-resolution quantization to correct and improve signal accuracy iteratively

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10834632B2Energy-efficient wireless communications for advanced networks with low-resolution digital-to-analog converters

Publication Date: 2020.11.10 AT&T INTELLECTUAL PROPERTY I L P

AI summary

Facilitating energy-efficient wireless communications for advanced networks (e.g., 4G, 5G, and beyond) with low-resolution digital-to-analog converters is provided herein. Operations of a system can comprise determining first values. Respective values of the first values can be digital samples of transmission and reception chains determined based on symbols transformed from bits. The operations can also comprise facilitating a quantization of the first values resulting in second values. Facilitating the quantization can be based on a cost function associated with processing the first values. Further, the operations can comprise outputting the second values as a continuous time signal over antennas of a base station device. The second values can comprise fewer values than the first values.