PUCCH Cross-Carrier Scheduling for Low-Latency UCI Transmission
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Solution Overview
Problem
Current mobile communication frameworks, particularly in NR, lack support for cross-carrier scheduling of PUCCH, leading to increased latency and alignment delays that hinder the application of URLLC and other latency-critical services due to the asymmetric uplink and downlink TDD patterns in TDD systems.
Innovation Solution
Implementing dynamic and semi-static cross-carrier scheduling for PUCCH by configuring multiple carriers with different TDD patterns and using a PUCCH carrier pattern to switch between them, allowing UCI transmission on the most suitable carrier based on a semi-static or dynamic configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If cross-carrier scheduling for PUCCH is not supported, then the system maintains simple PUCCH carrier configuration, but alignment delay increases and latency performance deteriorates
Solution Approach 1:
The patent segments the PUCCH transmission function across multiple carriers by introducing a PUCCH carrier pattern that indicates different PUCCH carriers for different slots. This allows the system to divide the uplink control information transmission across multiple component carriers, thereby reducing alignment delay without requiring complex per-slot carrier switching configurations.
Solution Approach 2:
The patent introduces dynamic PUCCH carrier selection through a PUCCH carrier pattern that can be configured semi-statically or dynamically. This allows the system to adaptively select which carrier to use for PUCCH transmission based on current TDD patterns and latency requirements, resolving the contradiction between simple configuration and reduced alignment delay.
2Reliability
If multiple PUCCH resources are allocated per uplink slot, then UCI transmission reliability improves, but transmission latency increases due to resource accumulation
Solution Approach 1:
The patent moves the PUCCH transmission resource selection from the time dimension (multiple resources in one slot) to the frequency dimension (different carriers). By introducing cross-carrier scheduling, the system can provide multiple PUCCH resources across different component carriers, improving reliability without requiring multiple time-accumulated transmissions within a single slot.
Data Source
AI summary
Various solutions for cross-carrier scheduling with respect to user equipment and network apparatus in mobile communications are described. An apparatus may receive a physical downlink control channel (PDCCH) on a component carrier (CC) in a PUCCH cell group. The apparatus may receive downlink data on a physical downlink shared channel (PDSCH) on a CC in the PUCCH cell group scheduled by the PDCCH. The apparatus may receive a physical uplink control channel (PUCCH) carrier pattern semi-statically configured via a radio resource control (RRC) signal or dynamically configured via a downlink control information (DCI). The apparatus may transmit uplink control information (UCI) corresponding to the downlink data on a PUCCH on a CC according to the PUCCH carrier pattern.