Uplink Shared Channel Configuration for Short TTI Compatibility
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Solution Overview
Problem
Future radio communication systems, such as LTE after Rel. 13 and 5G, face challenges in providing sufficient communication services due to the need for communicating small amounts of data in high frequency bands, where existing one-ms transmission time intervals (TTIs) may be insufficient.
Innovation Solution
The implementation of short TTIs, which are shorter than one-ms TTIs, with configurations that include maintaining compatibility with normal TTIs, allowing for efficient processing and reduced processing delay, and enabling the configuration of uplink shared channels (PUSCH) suitable for these systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If one-ms transmission time intervals (TTIs) are used in existing systems, then system compatibility is maintained, but processing delay increases and communication efficiency decreases in high frequency bands
Solution Approach 1:
The patent segments the transmission time interval into two types: normal TTIs (one-ms) for maintaining system compatibility and short TTIs (shorter than one-ms) for reducing processing delay. This segmentation allows the system to use appropriate TTI lengths depending on the communication scenario, thereby resolving the contradiction between maintaining compatibility and reducing delay.
Solution Approach 2:
The patent implements dynamic TTI configuration where the system can flexibly switch between normal TTIs and short TTIs based on communication conditions. This dynamic adaptation allows the system to optimize processing delay when needed while maintaining compatibility with existing systems during normal operation.
2Productivity
If short TTIs are implemented to reduce processing delay, then communication efficiency improves, but system complexity increases
Solution Approach 1:
The patent designs the uplink shared channel to serve multiple functions: it can operate as a normal uplink channel during normal TTIs and as a shortened uplink channel during short TTIs. This multi-functionality allows the same channel structure to adapt to different TTI lengths without requiring entirely separate channel designs, thereby reducing system complexity.
Solution Approach 2:
The patent changes the time parameter of the uplink shared channel based on TTI length. By adjusting the channel duration and resource allocation parameters according to whether a normal TTI or short TTI is being used, the system achieves efficient communication with short TTIs while maintaining a unified channel framework that limits complexity increase.
3Quantity of substance
If uplink shared channels are configured for short TTIs, then communication capacity in high frequency bands increases, but compatibility with existing systems decreases
Solution Approach 1:
The patent implements partial configuration of uplink shared channels for short TTIs. Instead of completely redesigning the channel for short TTIs, the system partially adapts the existing channel structure by adjusting timing and resource allocation parameters. This partial action maintains sufficient compatibility with existing systems while achieving the needed communication capacity in high frequency bands.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
The present invention is designed so as to carry out communication using an uplink shared channel having a configuration that is suitable for short TTIs. A user terminal according to the present invention configures short TTI so that one of two symbols, in which a demodulation reference signal for an uplink shared channel of a normal TTI is transmitted, is included in the short TTI. This user terminal transmits the uplink shared channel in the short TTI, and transmits a demodulation reference signal for the uplink shared channel of the short TTI in the one symbol.