PUCCH Cell Switching for HARQ-ACK Timing in Multi-Cell Uplink
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Solution Overview
Problem
The increasing number of user equipment (UEs) and the growing demand for data throughput in wireless communication systems pose challenges in efficiently managing limited radio resources, particularly in terms of latency and reliability.
Innovation Solution
A method for a user equipment (UE) to efficiently transmit hybrid automatic repeat request (HARQ) acknowledgement (ACK) information by performing physical downlink shared channel (PDSCH) reception in multiple cells, determining a HARQ-ACK feedback timing value, and transmitting the HARQ-ACK information in a slot on a secondary cell based on PUCCH cell switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PUCCH cell switching is implemented to transmit HARQ-ACK information on secondary cells, then system throughput and resource utilization are improved, but timing alignment and slot determination complexity increase
Solution Approach 1:
The patent implements dynamic PUCCH cell switching where the UE can switch between primary and secondary cells for PUCCH transmission based on scheduling conditions. The determination of slot n+K dynamically adapts to the selected PUCCH cell, allowing flexible resource utilization while maintaining proper timing alignment through the relationship between slot n (last overlapping slot) and feedback timing value K.
Solution Approach 2:
The patent extends the traditional single-cell PUCCH transmission to multi-cell dimension by allowing PUCCH transmission on both primary and secondary cells. The slot determination mechanism operates across multiple cell dimensions, selecting slot n from overlapping slots and determining slot n+K based on the chosen PUCCH cell, thereby utilizing additional spatial resources.
2Productivity
If HARQ-ACK feedback timing is determined based on multiple cells with different subcarrier spacings, then resource utilization efficiency is improved, but timing alignment accuracy deteriorates
Solution Approach 1:
The patent handles different subcarrier spacings by dynamically selecting the appropriate feedback timing value K from a set of configured values based on the selected PUCCH cell. The slot determination mechanism adapts parameters (slot n and slot n+K) according to the specific cell's subcarrier spacing, maintaining timing alignment accuracy while utilizing multiple cells with different spacing configurations.
3Adaptability or versatility
If the number of configured HARQ-ACK feedback timing values is increased to support multiple cells, then adaptability to different service requirements is improved, but control signal overhead increases
Solution Approach 1:
The patent establishes a universal set of HARQ-ACK feedback timing values configured for the primary cell that serves multiple functions: it provides timing guidance for both primary cell PUCCH transmission and secondary cell PUCCH transmission after switching. This multi-functional timing value set reduces control overhead while maintaining adaptability to different service requirements across multiple cells.
Data Source
AI summary
A UE may perform PDSCH reception in a plurality of cells including a primary cell and including a secondary cell configured for PUCCH cell switching, determine a slot n+K on the primary cell, based on a HARQ-ACK feedback timing value K for the PDSCH reception determined among a set of HARQ-ACK feedback timing values configured for the primary cell and on a last slot n overlapping with the PDSCH reception among slots of the primary cell, and transmit the HARQ-ACK information for the PDSCH reception in a slot m on the secondary cell, based on using the secondary cell for transmission of the HARQ-ACK information for the PDSCH reception based on the PUCCH cell switching. The slot m may be a slot including start of the slot n+K among slots of the secondary cell overlapping with the slot n+K.