Uplink Control Channel Format for Shortened TTI
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Solution Overview
Problem
Future radio communication systems, such as 5G, face challenges in reducing latency and supporting various communication services like eMBB, IoT, MTC, and URLLC, particularly in configuring an appropriate shortened Physical Uplink Control Channel (PUCCH) format for shortened Transmission Time Intervals (TTIs) to maintain communication quality and throughput.
Innovation Solution
A user terminal is designed to operate using shortened TTIs with a compatible uplink control channel format that supports multiple TTI durations, featuring variable symbol configurations and demodulation reference signal mappings to ensure efficient transmission of uplink control information, allowing for a trade-off between communication quality and overhead for both large and small payload sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If shortened TTI is used to reduce latency, then transmission speed is improved, but communication quality and spectral efficiency deteriorate
Solution Approach 1:
The patent applies dynamics by making the uplink control channel format adaptable to different TTI durations. The control channel format includes a variable number of symbols that can be configured according to the specific TTI length, allowing the system to dynamically adjust the control channel structure to match the shortened TTI requirements while maintaining sufficient resources for reliable control information transmission.
Solution Approach 2:
The patent changes key parameters of the uplink control channel format to suit shortened TTIs. Specifically, it modifies the number of symbols allocated to the control channel, the resource block allocation, and the demodulation reference signal configuration. These parameter adjustments enable the control channel to function effectively within the compressed time frame of shortened TTIs while preserving communication quality.
2Loss of time
If shortened TTI is used to reduce latency, then processing time is reduced, but spectral efficiency deteriorates
Solution Approach 1:
The patent implements dynamics by configuring the uplink control channel format to adapt to varying TTI durations. The control channel can be flexibly adjusted in terms of symbol count and resource allocation based on the specific shortened TTI configuration, enabling efficient use of spectral resources despite the reduced time available for transmission.
Solution Approach 2:
The patent creates a universal uplink control channel format that can serve multiple TTI durations (both normal and shortened). This multi-functional design allows the same control channel structure to be used across different TTI configurations, maximizing spectral efficiency by avoiding the need for separate specialized formats for each TTI type.
3Device complexity
If a specific sPUCCH configuration is not defined for shortened TTI, then system complexity is reduced, but communication throughput deteriorates
Solution Approach 1:
The patent defines a universal sPUCCH format that can be used for both normal and shortened TTIs. This single configurable format specifies the necessary parameters including the number of symbols, resource block allocation, and demodulation reference signal configuration. By providing this universal format with clear configuration rules, the patent maintains system simplicity while ensuring adequate throughput performance.
Solution Approach 2:
The patent specifies particular parameter configurations for the sPUCCH format adapted to shortened TTIs, including reduced symbol counts and adjusted resource allocations. These parameter changes are explicitly defined in the patent to ensure that the control channel operates efficiently within the constrained time resources of shortened TTIs without requiring complex additional configurations.
Data Source
AI summary
The present invention is designed to suitably support transmission of uplink control information even when shortened TTIs are used. According to one aspect of the present invention, a user terminal that communicates using a shortened transmission time interval (TTI), in which the TTI duration is shorter than one ms, has a control section that controls transmission of uplink control information, and a transmission section that transmits the uplink control information in a predetermined shortened TTI, using an uplink control channel format, which is for shortened TTIs and which is compatible with multiple TTI durations.