Codebook Subset Restriction Signaling for Lower Precoder Overhead
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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 resources and increased complexity.
Innovation Solution
A method that generates codebook subset restriction signaling by jointly restricting precoders within groups based on common components, such as beam precoders, using techniques like Kronecker products and bit pattern signaling to reduce the number of bits required for transmission, thereby lowering overhead while maintaining flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual bitmap restriction is used for each precoder, then precise codebook subset restriction is achieved, but signaling overhead increases significantly
Solution Approach 1:
The patent merges multiple individual precoder restriction indicators into a single joint restriction signal. Instead of using separate bitmap bits for each precoder, the invention groups precoders and uses a unified signaling mechanism to restrict multiple precoders simultaneously, thereby reducing signaling overhead while maintaining restriction precision.
Solution Approach 2:
The patent segments the codebook into multiple subsets or groups of precoders. By dividing the large codebook into smaller manageable groups, the system can apply restriction signaling more efficiently to each segment, reducing the total number of bits required compared to restricting the entire codebook individually.
2Reliability
If large codebook size is used, then better channel condition matching is achieved, but feedback channel capacity requirements increase
Solution Approach 1:
The patent applies partial action by restricting only certain subsets of precoders rather than the entire codebook. This allows the system to maintain a large codebook for better channel matching performance while only signaling restrictions for specific problematic precoder subsets, thereby reducing feedback overhead without sacrificing overall performance.
Solution Approach 2:
The patent applies local quality by allowing different parts of the codebook to have different restriction states. Some precoder subsets are restricted while others remain available, enabling the system to maintain high performance in unrestricted regions while managing overhead through selective restriction in specific local areas of the codebook.
3Quantity of substance
If codebook subset restriction is applied, then signaling overhead is reduced, but flexibility in precoder selection is limited
Solution Approach 1:
The patent implements dynamic codebook subset restriction where the restricted subsets can be adaptively configured based on channel conditions, interference patterns, and network requirements. This dynamic approach allows the system to maintain flexibility by adjusting which precoders are restricted in different scenarios, rather than applying static restrictions that would permanently limit adaptability.
Data Source
AI summary
A network node signals to a wireless communication device which precoders in a codebook are restricted from being used. The network node 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 sends the generated signaling to the wireless communication device.