Grouped Codebook Restriction Signaling for Precoder Feedback
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Solution Overview
Problem
The existing methods for signaling codebook subset restrictions in wireless communication systems face high overhead due to the need for bitmaps that individually restrict each precoder, especially in large antenna arrays and multi-dimensional scenarios, leading to inefficient use of feedback resources.
Innovation Solution
A method that generates codebook subset restriction signaling by jointly restricting precoders based on common components, such as beam precoders, using bit patterns that depend on reference configurations, reducing the number of bits required for signaling by assuming likely restrictions and grouping precoders accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bitmap is used to individually restrict each precoder in the codebook, then full flexibility for restricting any subset of precoders is achieved, but the signaling overhead becomes very large especially for large antenna arrays
Solution Approach 1:
The patent merges multiple individual precoder restriction bits into grouped restriction patterns. Instead of using separate bits for each precoder, precoders are grouped together and restricted using shared bitmap patterns, thereby reducing the total number of bits required while maintaining the ability to restrict any desired subset of precoders
Solution Approach 2:
The codebook is segmented into multiple groups or subsets of precoders. Each group can be independently restricted using its own bitmap pattern, allowing the system to apply restriction at a coarser granularity level rather than at the individual precoder level, thus reducing overall signaling overhead
2Measurement precision
If a large codebook with many elements is used, then better matching of current channel conditions is achieved, but the feedback channel capacity is exceeded when reporting all precoder indicators
Solution Approach 1:
The patent extracts and reports only the most relevant precoder indicator information rather than all possible precoder details. By identifying and reporting only the dominant or most significant precoder parameters, the system maintains accurate channel condition matching while reducing the amount of feedback data transmitted
Solution Approach 2:
Instead of reporting complete information about all precoders in the large codebook, the system reports partial information about a subset of relevant precoders. This partial reporting approach provides sufficient channel condition matching accuracy while staying within feedback channel capacity constraints
Data Source
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AI summary
A network node (10) signals to a wireless communication device (14) which precoders in a codebook are restricted from being used. The network node (10) in this regard generates codebook subset restriction signaling that, for each of one or more groups of precoders, jointly restricts the precoders in the group by restricting a certain component (e.g., a certain beam precoder) that the precoders in the group have in common. This signaling may be for instance rank-agnostic signaling that jointly restricts the precoders in a group without regard to the precoders' transmission rank. Regardless, the network node (10) sends the generated signaling to the wireless communication device (14).