PUCCH Cell Switching With Patterned Timing for URLLC
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Solution Overview
Problem
The current PUCCH configuration in 3GPP NR Rel-15 and Rel-16 specifications fails to meet the low latency requirements of URLLC due to confusion over time resource units post-cell switching, especially when multiple target PUCCH cells are indicated with different subcarrier spacings or cyclic prefixes, and the interaction between dynamic and semi-static carrier switching is not adequately specified.
Innovation Solution
A method for PUCCH cell switching in user equipment (UE) involving the reception of an RRC message with PUCCH cell patterns and subcarrier spacings, and transmission on determined PUCCH cells during time resource units, using bitmaps and patterns to clarify cell switching and handle different numerologies and switching types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple target PUCCH cells are configured with different subcarrier spacings or cyclic prefixes, then the system provides flexibility for URLLC low latency requirements, but the UE becomes confused about which time resource unit to use for PUCCH transmission after cell switching
Solution Approach 1:
The patent segments the time resource allocation by introducing separate time domain offset parameters (K1, K2, K3) for different PUCCH cell types (primary PUCCH cell and secondary PUCCH cell). This segmentation allows the UE to clearly identify which time resource unit corresponds to which PUCCH cell, eliminating confusion while maintaining the flexibility of multiple target cells with different numerologies for URLLC low latency requirements
Solution Approach 2:
The patent introduces a new dimension of control by adding explicit time domain offset indicators in the DCI message. This dimensional addition provides the UE with clear timing information across multiple cells with different subcarrier spacings, resolving the ambiguity without sacrificing the adaptability of the multi-cell configuration
2Productivity
If dynamic carrier switching and semi-static carrier switching are both applied, then the system achieves better performance optimization, but the interaction mechanism between the two switching types needs to be specified
Solution Approach 1:
The patent implements a dynamic interaction mechanism where the DCI message can dynamically indicate both the target PUCCH cell and the time domain offset. This dynamic approach allows the system to optimize performance by flexibly switching between dynamic and semi-static carrier switching based on real-time conditions, while the standardized DCI format keeps the interaction mechanism manageable rather than complex
3Adaptability or versatility
If PUCCH configuration is provided for multiple PUCCH cells, then the system can support carrier switching, but the current configuration does not meet the low latency requirement of URLLC
Solution Approach 1:
The patent applies preliminary action by pre-configuring multiple PUCCH cells with different numerologies (subcarrier spacings and cyclic prefixes) suitable for URLLC low latency requirements. The RRC message pre-establishes the PUCCH Cell Pattern and time domain offsets, so when carrier switching is needed, the UE can immediately switch to the pre-configured appropriate cell without additional configuration delay, thus meeting URLLC latency requirements while maintaining carrier switching capability
Data Source
AI summary
A method related to physical uplink control channel (PUCCH) cell switching and a user equipment (UE) are provided. The method includes: receiving a radio resource control (RRC) message from a base station; determining a PUCCH cell from the first cell and the second cell according to at least one PUCCH cell pattern; and transmitting the PUCCH transmission on the PUCCH cell during the time resource units. The RRC message includes at least one PUCCH cell pattern associated with multiple cell indexes and a first subcarrier spacing (SCS) associated with a first cell and a second SCS associated with a second cell. Each cell index corresponds to a cell, and the PUCCH cell pattern indicates which cell corresponds to one time resource unit used for PUCCH transmission.