Massive MIMO Beamformer Selection with Partial Channel Information
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Solution Overview
Problem
In massive MIMO communication systems, the challenge lies in selecting an appropriate modulation and coding scheme (MCS) when only partial channel information is available, due to the need for efficient beamforming design and the high overhead of transmitting full channel information through sounding reference signals (SRS).
Innovation Solution
The method involves determining beamformers for known and unknown channels using singular value decomposition (SVD) of the known channel matrix and applying random orthogonal beamformers for unknown channels, followed by selecting the MCS based on channel quality indicator (CQI) feedback to optimize transmission throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full channel information is transmitted through sounding reference signals, then beamforming design accuracy is improved, but system overhead increases
Solution Approach 1:
The patent applies partial action by using only a subset of antenna elements for SRS transmission instead of all antennas. The BS configures the UE to transmit SRS from a selected subset of antennas, which provides sufficient channel information for beamforming design while significantly reducing the overhead compared to using all antennas. This resolves the contradiction by achieving adequate measurement precision without the excessive overhead of full channel information transmission.
2Quantity of substance
If channel information is obtained through SRS with subset of antennas, then system overhead is reduced, but beamforming design accuracy deteriorates
Solution Approach 1:
The patent employs feedback mechanisms where the UE reports channel quality indicator (CQI) information back to the BS based on the subset of antennas used for SRS transmission. This feedback allows the BS to compensate for the limited channel information by adjusting beamforming weights and selecting appropriate modulation and coding schemes, thereby maintaining beamforming design accuracy despite using only a subset of antennas for SRS.
3Productivity
If MCS is selected based on partial channel information, then system throughput is improved, but transmission reliability deteriorates
Solution Approach 1:
The patent implements dynamic MCS selection where the BS adjusts the modulation and coding scheme based on real-time channel quality feedback from the UE. The BS determines appropriate beamforming weights and selects MCS dynamically according to the channel conditions observed from the subset of antennas, allowing the system to adapt to changing conditions and maintain both high throughput and reliable transmission by optimizing the MCS for the actual channel state.
Data Source
AI summary
A method and system are herein disclosed. The method includes receiving sounding reference signals (SRS) at a massive multiple-input multiple-output (MIMO) base station (BS) from a user equipment (UE), determining, at the BS, beamformers for known channels of the SRS, determining, at the BS, beamformers for unknown channels of the SRS based on the determined beamformers for the known channels, and selecting a modulation and coding scheme (MCS) based on the determined beamformers.