PUCCH Format Configuration for Shortened TTI Uplink Control
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Solution Overview
Problem
In wireless communication systems supporting unlicensed bands, there is a challenge in efficiently transmitting uplink control information between user equipment (UE) and base stations, particularly when the transmission time interval (TTI) is shorter than a single subframe, as existing methods do not effectively optimize the physical uplink control channel (PUCCH) format for efficient data transfer.
Innovation Solution
The method involves configuring a PUCCH format according to the TTI length by the base station, allowing the UE to transmit uplink control information in a subframe using a PUCCH format tailored to the TTI length, which includes options like rate-matching or puncturing to accommodate shorter TTIs, ensuring efficient data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a UE transmits uplink control information with a TTI shorter than a single subframe, then the data transfer efficiency is improved, but the PUCCH format compatibility and reliability deteriorate
Solution Approach 1:
The patent introduces dynamic PUCCH format selection based on TTI length. The base station configures multiple PUCCH formats (first format for normal TTI, second format for shortened TTI) and dynamically indicates which format to use through downlink control information. This allows the system to adapt the PUCCH structure to match the actual TTI duration, ensuring reliable control information transmission whether using normal or shortened TTIs.
Solution Approach 2:
The patent changes key PUCCH parameters including format type, resource allocation, and timing based on TTI length. For shortened TTIs, the system adjusts the PUCCH format to accommodate the reduced time duration, modifies resource element mapping, and adjusts transmission timing. These parameter changes ensure that PUCCH transmission remains reliable regardless of whether normal or shortened TTI is used.
2Device complexity
If a fixed PUCCH format is used for all TTI lengths, then the system complexity is reduced, but the adaptability to different TTI lengths deteriorates
Solution Approach 1:
The patent implements dynamic PUCCH format configuration where the base station maintains multiple PUCCH format definitions and selectively activates the appropriate format based on the scheduled TTI length. The base station sends format indication information through downlink control information, allowing the UE to switch between formats without complex local decision-making logic. This centralized dynamic configuration provides adaptability while keeping UE implementation relatively simple.
Solution Approach 2:
The base station pre-configures multiple PUCCH formats and stores them in the UE's memory before actual transmission occurs. When a shortened TTI is scheduled, the base station simply indicates which pre-configured format to use, avoiding the need for real-time format generation or complex calculations. This preliminary configuration approach reduces runtime complexity while maintaining full adaptability.
Data Source
AI summary
Disclosed are a method for transmitting/receiving uplink control information between a terminal and a base station and a device supporting same in a licensed assisted access (LAA) system in which the base station or the terminal executes listen-before-talk (LBT)-based signal transmission. Specifically, disclosed are: a method for a terminal efficiently transmitting uplink control information to a base station when the terminal transmits the uplink control information to a transmission time interval (TTI) that is shorter than the length of one subframe; and a device supporting same.