Shortened TTI Uplink Transmission Configuration in LTE
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Solution Overview
Problem
In LTE and LTE-A systems, there is a need to transmit signals in a transmission time interval shorter than a subframe, requiring a method for a UE to determine the start and duration of a shortened TTI, which is not effectively addressed by existing technologies.
Innovation Solution
A method where a terminal receives RRC messages and DCI from a base station, including information about the number of time domain scheduling units and symbols for PUSCH, to transmit uplink data based on the received information, applying this information to each scheduling unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a shortened TTI is used to reduce transmission time interval, then data transmission speed is improved, but the method for determining start and duration of shortened TTI becomes complex
Solution Approach 1:
The patent segments the TTI structure into distinct components: a start indicator field in DCI that specifies the starting symbol of the shortened TTI, and a duration indicator that specifies the number of symbols. This segmentation allows the UE to independently determine each parameter, simplifying the overall determination process while enabling flexible shortened TTI configurations for improved transmission speed
Solution Approach 2:
The patent implements preliminary action by pre-configuring the UE with RRC parameters that define the set of possible shortened TTI durations before actual data transmission. The DCI then carries only the necessary start and duration indicators selected from these pre-configured options, reducing the complexity of real-time TTI parameter determination while maintaining flexibility for speed optimization
2Duration of action of moving object
If existing technologies are used, then system compatibility is maintained, but the ability to transmit signals in shorter time intervals than a subframe is limited
Solution Approach 1:
The patent applies dynamics by making the TTI duration configurable and variable rather than fixed. The UE can dynamically adjust the shortened TTI parameters based on DCI indications, allowing the system to adapt transmission time intervals to varying channel conditions and traffic requirements, thus achieving both shorter transmission durations and enhanced versatility
Solution Approach 2:
The patent implements parameter changes by introducing new RRC parameters (such as tti-PayloadSize, tti-StartSymbol) and DCI fields that enable flexible configuration of shortened TTI characteristics. These parameter changes allow the system to transition from fixed subframe-based transmission to variable-length shortened TTI transmission, achieving reduced transmission time while maintaining system compatibility through controlled parameter evolution
Data Source
AI summary
Provided is a terminal that includes a transceiver that transmits and receives signals, and a controller that receives, from a base station, control information including uplink configuration information for a plurality of subframes, to confirm information, for uplink transmission, from the uplink configuration information, and transmit an uplink signal based on the information for the uplink transmission, and a method for controlling the terminal.