Uplink Control Information Codebooks for Reduced CSI Overhead
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Solution Overview
Problem
The overhead for uplink control information (UCI) transmission is excessive due to the need to report Channel State Information (CSI) for multiple beams in New Radio (NR) communication systems, particularly with the enhanced type II codebook, which lacks subband parameters and requires efficient handling of CSI omission and compression.
Innovation Solution
A method for UCI transmission involving the determination of codebooks and bit sequences to indicate the presence or absence of gains for spatial and frequency domain basis pairs, with adjustments and discarding of non-zero coefficients to fit available resources, and a two-step FD basis selection to reduce overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If CSI is reported for multiple beams in NR communication systems using enhanced type II codebook, then channel state information completeness is improved, but UCI transmission overhead increases excessively
Solution Approach 1:
The patent segments the codebook into first and second codebooks corresponding to different transmission layers, and divides the CSI reporting into parts for different beams. This segmentation allows selective reporting of CSI for only the active transmission layers, reducing overhead while maintaining completeness for reported beams.
Solution Approach 2:
The patent applies local quality by differentiating between transmission layers and beams, reporting CSI only for active layers and using beam indication rather than full CSI for inactive beams. This localized approach reduces the quantity of reported information while maintaining necessary channel state awareness.
2Loss of information
If full CSI is reported for all transmission layers, then channel state information completeness is improved, but available uplink resources are insufficient
Solution Approach 1:
The patent applies partial action by reporting full CSI only for active transmission layers and using compressed beam indication for inactive layers. This partial reporting approach provides sufficient channel state information for active communication while avoiding the excessive overhead of reporting for all layers.
Solution Approach 2:
The patent changes the reporting parameter from full CSI details to beam indication parameters for inactive transmission layers. This parameter change reduces the amount of data to be transmitted while maintaining the ability to identify active beams for communication.
3Device complexity
If enhanced type II codebook is used without subband parameters, then codebook complexity is reduced, but CSI reporting overhead increases
Solution Approach 1:
The patent segments the codebook structure into layer-specific components, allowing the simplified enhanced type II codebook to be applied selectively only where needed (for active layers), thereby reducing overall reporting overhead while maintaining codebook simplicity.
Solution Approach 2:
The patent uses the simplified codebook structure partially for active transmission layers where full CSI is needed, and relies on beam indication for inactive layers. This partial application of the simplified codebook reduces reporting overhead compared to using the full codebook with subband parameters for all layers.
Data Source
AI summary
Embodiments of the present disclosure relate to methods, devices and computer readable media for Uplink Control Information (UCI) transmission. In example embodiments, a method for communication includes determining, at a terminal device, a first part of a first codebook and a second part of a second codebook, the first part and the second part indicating presence or absence of gains for a plurality of pairs of spatial domain (SD) basis and frequency domain (FD) basis, the first codebook and the second codebook being used for different transmission layers between the terminal device and a network device; determining a bit sequence based on the first part and the second part, each bit in the bit sequence corresponding to one of the plurality of pairs of SD basis and FD basis; and transmitting, to the network device, uplink control information including the bit sequence.