Digital-Analog Hybrid Beamforming for Millimeter Wave Power Reduction
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Solution Overview
Problem
Current millimeter wave communication systems face challenges in reducing power consumption and hardware costs due to the need for numerous RF chains, while also requiring efficient signal processing and supporting multiple users in dense urban areas.
Innovation Solution
The implementation of digital-analog hybrid beamforming technology, which reduces the number of RF chains by using a large number of antennas, performs digital beamforming based on received feedback information, and applies analog beamforming using a prestored codebook, thereby optimizing power usage and supporting multiple users in millimeter wave channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large number of RF chains are used to support many antennas for beamforming, then beamforming performance and transmission capacity are improved, but power consumption and hardware cost increase significantly
Solution Approach 1:
The patent segments the beamforming function into two independent parts: digital beamforming (performed by a limited number of RF chains) and analog beamforming (performed by phase shifters at each antenna). This segmentation allows the system to achieve full MIMO capability with far fewer RF chains, directly reducing power consumption while maintaining transmission capacity.
Solution Approach 2:
The patent introduces a new dimension of analog beamforming in the RF domain, complementing the existing digital beamforming in the baseband domain. By adding this spatial dimension control through phase shifters, the system achieves enhanced beamforming performance without proportionally increasing the number of power-consuming RF chains.
2Productivity
If a large number of RF chains are used to support many antennas for beamforming, then beamforming performance and transmission capacity are improved, but hardware cost increases significantly
Solution Approach 1:
The patent segments the beamforming function into two independent parts: digital beamforming (performed by a limited number of RF chains) and analog beamforming (performed by phase shifters at each antenna). This segmentation allows the system to achieve full MIMO capability with far fewer RF chains, directly reducing power consumption while maintaining transmission capacity.
Solution Approach 2:
The patent uses phase shifters at each antenna element to create analog beamforming capability, effectively copying the beamforming function across all antenna elements without requiring dedicated RF chains for each antenna. This approach significantly reduces hardware cost while maintaining beamforming performance.
3Adaptability or versatility
If digital beamforming is performed for all users simultaneously, then user support capability is improved, but signal processing complexity increases
Solution Approach 1:
The patent segments user support into two stages: first, analog beamforming groups users into different spatial beams; second, digital beamforming handles multiple users within each beam group. This segmentation reduces the dimensionality of signal processing required at each stage, making simultaneous multi-user support feasible with limited RF chains.
Solution Approach 2:
The patent introduces spatial dimension control through analog beamforming, which separates users into different spatial groups before digital processing. This dimensional separation reduces the complexity of digital signal processing by dividing the overall processing task into smaller, more manageable sub-tasks for each RF chain.
Data Source
AI summary
Disclosed is a method and system for digital-analog hybrid beamforming in a millimeter wave downlink channel. A hybrid beamforming method in a downlink channel with respect to at least one user terminal belonging to a transmission apparatus includes receiving feedback information from each of the at least one user terminal; selecting at least one user terminal for transmitting a transmission signal based on the received feedback information; performing digital beamforming with respect to the selected at least one user terminal; and performing analog beamforming with respect to the selected at least one user terminal based on a prestored codebook. The codebook includes a desired number of subsets calculated based on a number of transmit antennas and a number of radio frequency (RF) chains, and each of the subsets includes a number of beamforming vectors corresponding to the number of RF chains.