Precoding Matrix Subset Selection for Wireless Mobility
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Solution Overview
Problem
Existing wireless communication systems face performance degradation at high mobility scenarios due to channel variations, as closed loop precoding is not suitable for fast-changing channels, and open loop precoding lacks adaptability to different antenna setups and mobility conditions.
Innovation Solution
A method that defines at least two subsets of precoding matrices for each transmission rank, selecting the subset based on channel quality estimates, antenna setup, and antenna gain imbalance, to improve precoding performance for both uplink and downlink in high mobility scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If closed loop precoding is used, then precoding performance is improved for static channels, but performance degrades at high mobility scenarios due to channel variations
Solution Approach 1:
The codebook is segmented into multiple subsets (first subset and second subset) with different properties. The first subset contains precoding matrices optimized for static or low mobility scenarios, while the second subset contains precoding matrices optimized for high mobility scenarios. This segmentation allows the system to adapt to different channel conditions by selecting the appropriate subset.
Solution Approach 2:
The system dynamically switches between different precoding matrix subsets based on channel conditions, specifically mobility indicators. When mobility is detected to be high, the system switches to the second subset; when mobility is low, it uses the first subset. This dynamic adaptation resolves the contradiction between optimized static performance and adaptability to channel variations.
2Adaptability or versatility
If open loop precoding is used, then adaptability to different scenarios is improved, but precoding performance lacks optimization for specific antenna setups and mobility conditions
Solution Approach 1:
Different subsets of precoding matrices are designed with local optimizations for specific scenarios. The first subset is locally optimized for static channels with specific antenna configurations, while the second subset is locally optimized for high mobility scenarios. This local quality approach ensures that each subset provides optimal performance for its intended scenario, resolving the contradiction between adaptability and performance optimization.
3Device complexity
If a single codebook is used for all scenarios, then device complexity is reduced, but the system cannot support different antenna setups and mobility conditions effectively
Solution Approach 1:
The codebook is divided into multiple subsets with distinct characteristics. Each subset contains precoding matrices tailored for specific scenarios (static vs. high mobility). This segmentation increases adaptability while maintaining a relatively simple overall structure, as the subsets are organized systematically and selection is based on simple mobility indicators.
Solution Approach 2:
The multi-subset codebook structure serves multiple functions: it provides optimized precoding for static scenarios, optimized precoding for high mobility scenarios, and a mechanism for seamless adaptation between scenarios. This multi-functionality resolves the contradiction by making the codebook structure itself adaptable to different requirements without requiring entirely separate systems.
Data Source
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AI summary
The present invention relates to a method in a multiple antenna wireless communication system, said wireless communication system comprising at least one transmit node and at least one receive node, said method comprising the steps of: signalling by said receive node at least one first transmission rank r to said transmit node, where 1< r < R, wherein R is a maximum available rank for a transmission between said transmit node and said receive node, and wherein at least one predefined precoding matrix corresponds to said first transmission rank r; determining by said transmit node a second transmission rank r' for transmitting data from said transmit node to said receive node, where 1< r' < R, and comprising the further steps of: defining at least two subsets of precoding matrices for at least one of said at least one first transmission rank r; selecting one of said at least two subsets of precoding matrices based on a channel quality estimate for a radio channel between said transmit node and said receive node; and signalling said selected one subset of precoding matrices, wherein said selected one subset of precoding matrices is associated with said at least one predefined precoding matrix corresponding to said at least one first transmission rank r. Furthermore, the invention also relates to a method in a receive node, a receive node device, a method in a transmit node, a transmit node device, a computer program and a computer program product.