Codebook Subset Restriction for Uplink Transmission
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Solution Overview
Problem
In 5G/NR mobile communication systems, the issue of relative phase discontinuity (RPD) and antenna gain imbalance (AGI) affects uplink transmission, particularly due to diverse antenna configurations and propagation conditions, which complicates the design of codebooks for wireless communications.
Innovation Solution
A method involving a processor in user equipment (UE) that receives a signal indicating codebook subset restriction (CBSR) from a network node, selects appropriate codewords or codebooks from a master codebook, and performs physical uplink shared channel (PUSCH) transmission, incorporating techniques such as port combining and selection to mitigate RPD and AGI, while supporting both DFT-OFDM and CP-OFDM waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a comprehensive codebook is designed to support diverse antenna configurations and propagation conditions, then the adaptability of uplink transmission is improved, but the device complexity and signaling overhead increase
Solution Approach 1:
The codebook is segmented into multiple subsets, each optimized for specific antenna configurations and propagation conditions. The network node can indicate which subset to use via CBSR, allowing the UE to select an appropriate codebook without needing to process the entire comprehensive codebook, thus reducing complexity while maintaining adaptability.
Solution Approach 2:
The codebook selection is made dynamic through CBSR signaling from the network node. The UE can adaptively switch between different codebook subsets based on current transmission conditions, antenna configuration, and channel characteristics, enabling flexibility without requiring a single overly complex static codebook design.
2Ease of operation
If codebook subset restriction (CBSR) is implemented to reduce codebook selection complexity, then the ease of operation is improved, but the loss of information increases due to restricted codebook options
Solution Approach 1:
CBSR is implemented dynamically, allowing the network node to adjust the restricted codebook subset based on current channel conditions, UE capability, and transmission requirements. This ensures that while the codebook is restricted for ease of selection, the restriction is optimized to minimize performance loss by excluding only suboptimal codebook options.
Solution Approach 2:
The CBSR mechanism changes parameters such as codebook subset size and composition based on transmission conditions. By adapting these parameters dynamically, the system maintains ease of operation through restricted selection while minimizing information loss by ensuring the restricted subset still contains appropriate codebooks for current conditions.
3Adaptability or versatility
If multiple codebooks are supported for different waveforms (DFT-OFDM and CP-OFDM), then the adaptability to waveform requirements is improved, but the device complexity increases
Solution Approach 1:
The codebook support is segmented by waveform type. Separate codebooks are maintained for DFT-OFDM and CP-OFDM waveforms, each optimized for the specific requirements of that waveform. This segmentation allows the UE to manage multiple codebooks more efficiently by processing only the relevant codebook for the active waveform, reducing overall management complexity.
Solution Approach 2:
The codebook design incorporates universal structures and principles that can be applied across different waveform types. By using common codebook frameworks that can be adapted to both DFT-OFDM and CP-OFDM, the patent reduces the complexity of managing multiple waveform-specific codebooks while maintaining the adaptability to support both waveforms effectively.
Data Source
AI summary
Various solutions with respect to codebook-based uplink transmission in wireless communications are described. A user equipment (UE) receives a signal indicating codebook subset restriction (CBSR) from a network node of a wireless network. The UE selects one or more codewords or a codebook from a master codebook based on the CBSR. The master codebook includes codewords from multiple components. The UE then performs a physical uplink shared channel (PUSCH) transmission to the network node using the one or more codewords or the codebook.