Massive MU-MIMO Power Allocation with Quantization Distortion
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Solution Overview
Problem
Massive MU-MIMO systems face challenges with power consumption and signal distortion due to the use of low-resolution data converters, particularly the 'near-far effect' where strong signals overpower weak signals, impairing communication for user equipment with varying received power conditions.
Innovation Solution
A method for a wireless communication device that estimates communication channels and quantization distortion to jointly determine optimal transmission power and resources for each user equipment, optimizing performance metrics such as worst-case throughput or overall throughput to mitigate signal impairment and accommodate users with different power conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low-resolution data converters are used to reduce power consumption, then power consumption is reduced, but quantization distortion increases causing the near-far effect where strong signals overpower weak signals
Solution Approach 1:
The patent changes the parameter of quantization resolution dynamically. Low-resolution data converters are used during normal operation to minimize power consumption, while high-resolution data converters are activated selectively during calibration phases or when serving users with similar received power levels. This parameter change allows the system to adapt between power efficiency and measurement precision based on operational conditions.
Solution Approach 2:
The system dynamically switches between low-resolution and high-resolution data converters based on the received power conditions of active users. When users have similar received power levels, high-resolution converters are used to maintain signal quality. When there is a large power difference (near-far scenario), the system transitions to low-resolution converters with activated compensation mechanisms to reduce power consumption while managing distortion.
2Measurement precision
If high-resolution data converters are used to reduce quantization distortion, then signal quality is improved, but power consumption increases exponentially
Solution Approach 1:
The patent implements parameter changes by switching the quantization resolution based on operational requirements. High-resolution data converters are used only when necessary (during calibration or when users have similar power levels), while low-resolution converters handle normal operations with varying power conditions. This selective parameter change reduces overall power consumption while maintaining signal quality when needed.
Solution Approach 2:
The system employs periodic calibration phases where high-resolution data converters are activated temporarily to update channel state information and compensation parameters. During these periodic high-resolution phases, the system captures accurate signal characteristics, then switches to low-resolution mode for data transmission. This periodic action allows the system to benefit from high-resolution measurements without continuously incurring the high power cost.
3Reliability
If more power is directed towards UEs with high attenuation to compensate for path loss, then coverage is improved, but quantization distortion from these high-power signals impairs signals directed towards UEs with low attenuation
Solution Approach 1:
The patent introduces digital signal processing techniques as intermediaries to separate and process signals from different users. Advanced signal processing algorithms act as intermediaries that can distinguish between high-power and low-power user signals in the digital domain, allowing the system to maintain high transmit power for coverage while preventing distortion from affecting other users. This intermediary processing layer decouples the power allocation from the distortion problem.
Solution Approach 2:
The system dynamically adjusts the quantization resolution parameter based on the power allocation strategy. When high transmit power is directed towards users with high attenuation to improve coverage, the system simultaneously activates high-resolution data converters to accurately capture and process these high-power signals without excessive distortion. This parameter change ensures that the improved coverage does not come at the cost of signal impairment to other users.
Data Source
AI summary
Disclosed is a method of a first wireless communication device configured for massive multi-user multiple-input multiple output (MU-MEMO) communication with two or more second wireless communication devices. The first wireless communication device comprises a plurality of antenna ports, each antenna port associated with at least one of a digital-to-analog converter (DAC) and an analog-to-digital converter (ADC). The method comprises acquiring an estimation of a communication channel between the first wireless communication device and the second wireless communication devices and acquiring an estimation of a quantization distortion caused by either DACs or ADCs. The method also comprises jointly determining (for the two or more second wireless communication devices) a transmission power and a transmission resource for each of the second wireless communication devices, wherein the joint determination is based on the estimation of the communication channel and on the estimation of the quantization distortion. Corresponding apparatus, network node and computer program product are also disclosed.