Wireless Communication TTI Determination for Latency Reduction
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Solution Overview
Problem
Current wireless communication methods face challenges in reducing latency, particularly in determining valid transmission time intervals (TTIs) for physical channels, which can increase UE complexity and decoding times, especially when TTI lengths vary within a subframe.
Innovation Solution
The approach involves determining valid TTIs based on resource element numbers within a subframe and using bitmaps in the RRC or MAC layer to indicate candidate TTIs, allowing the UE to blindly decode only the necessary TTIs, optimizing bitmap size according to TTI lengths, and enabling transmission in multiple TTIs if individual TTIs are not sufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE blindly decodes all possible TTIs in a subframe to ensure reliable reception, then the reliability of physical channel reception is improved, but the UE complexity and decoding time increase significantly
Solution Approach 1:
The patent extracts and identifies only the valid TTIs within a subframe based on resource element patterns, allowing the UE to focus decoding efforts only on these extracted valid TTIs rather than all possible TTIs, thereby reducing complexity while maintaining reliability
Solution Approach 2:
The patent performs preliminary identification of valid TTIs using resource element pattern matching before the actual decoding process, enabling the UE to prepare and limit its decoding operations in advance, thus reducing overall decoding time and complexity
2Reliability
If the UE blindly decodes all possible TTIs in a subframe to ensure reliable reception, then the reliability of physical channel reception is improved, but the decoding time increases significantly
Solution Approach 1:
The patent extracts only the valid TTI positions from the subframe based on resource element patterns, eliminating unnecessary decoding operations on invalid TTIs and thereby significantly reducing decoding time while preserving reliability
Solution Approach 2:
The patent performs preliminary identification of valid TTI positions using resource element pattern matching before the actual decoding process, enabling the UE to limit its decoding operations in advance and reduce overall decoding time
3Device complexity
If a fixed-size bitmap is used to indicate candidate TTIs, then the signaling structure is simplified, but the bitmap size becomes inefficient when TTI lengths vary
Solution Approach 1:
The patent makes the bitmap size dynamic and adaptive to the actual TTI configuration in each subframe, allowing the bitmap to expand or contract based on the number and length of TTIs, thereby optimizing signaling efficiency while maintaining structural simplicity
Solution Approach 2:
The patent changes the bitmap size parameter according to the TTI configuration, adapting the signaling overhead to match the actual transmission requirements, which improves communication efficiency without significantly increasing system complexity
4Loss of time
If the TTI length is reduced from 1 ms to 1 OFDM symbol to reduce latency, then the transmission latency is largely reduced, but the UE complexity in determining valid TTIs increases
Solution Approach 1:
The patent extracts valid TTI positions using resource element pattern matching, which provides a systematic method to handle the increased number of shorter TTIs without proportionally increasing UE complexity, thus maintaining latency reduction benefits
Solution Approach 2:
The patent uses resource element patterns as templates to identify valid TTIs, creating a reusable recognition mechanism that simplifies the process of determining validity among multiple short TTIs, thereby controlling complexity despite reduced TTI length
Data Source
AI summary
Provided are an eNB, a UE and wireless communication methods. A UE according to an embodiment of the present disclosure can comprise circuitry operative to determine valid transmission time interval(s) (TTI(s)) for a physical channel in a subframe based on the resource element (RE) number of each TTI in the subframe; and a receiver operative to receive the physical channel in one or more of the valid TTI(s) by blindly decoding part or all of the valid TTI(s), wherein each TTI comprises 1-7 orthogonal frequency division multiplexing (OFDM) symbols.