Scalable TTI Design for Low Latency Mission Critical Traffic
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Solution Overview
Problem
Wireless communication networks face challenges in achieving low latency and high reliability, particularly for mission critical traffic that requires timely and error-free transmission, as existing HARQ schemes rely on round trip times that can be lengthy, impacting the efficiency and reliability of data transmission.
Innovation Solution
The implementation of a scalable transmission time interval (TTI) design with optimized HARQ, where data is transmitted during a first TTI and feedback is processed and transmitted during subsequent TTIs, allowing for early pilot and acknowledgement scheduling, and using multi-symbol TTIs to reduce latency and increase link budget, enabling faster turn-around HARQ and improved communication performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional HARQ schemes are used with fixed TTI duration, then system compatibility is maintained, but latency is increased and reliability is reduced for mission critical traffic
Solution Approach 1:
The patent implements dynamic TTI scaling where the TTI duration is adjusted based on traffic requirements. For mission critical traffic, the TTI is scaled down to a shorter duration (e.g., 0.5ms or 0.25ms) to reduce latency, while for non-critical traffic, the traditional TTI duration is maintained. This dynamic adaptation allows the system to optimize latency and reliability for different traffic types without compromising overall system compatibility.
Solution Approach 2:
The patent changes the TTI duration parameter from a fixed value to a scalable parameter. By introducing a scaling factor that can adjust the TTI duration based on traffic characteristics, the system can modify this key parameter to achieve lower latency for mission critical traffic while maintaining compatibility with existing systems that use traditional TTI durations.
2Loss of time
If TTI duration is reduced to decrease latency, then latency is improved, but processing time for feedback generation is reduced which may impact reliability
Solution Approach 1:
The patent segments the TTI into distinct phases: a first portion for data transmission and a second portion for feedback processing and transmission. This segmentation allows the data to be transmitted in a shortened TTI to reduce latency, while the feedback processing occurs in a separate, adequately timed portion that ensures reliable processing. The feedback TTI is scaled appropriately to provide sufficient processing time without increasing the overall latency of the data transmission.
3Adaptability or versatility
If scalable TTI with multiple configurations is implemented, then adaptability to different traffic requirements is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic TTI scaling where the TTI duration is adjusted based on traffic requirements. For mission critical traffic, the TTI is scaled down to a shorter duration (e.g., 0.5ms or 0.25ms) to reduce latency, while for non-critical traffic, the traditional TTI duration is maintained. This dynamic adaptation allows the system to optimize latency and reliability for different traffic types without compromising overall system compatibility.
Solution Approach 2:
The patent changes the TTI duration parameter from a fixed value to a scalable parameter. By introducing a scaling factor that can adjust the TTI duration based on traffic characteristics, the system can modify this key parameter to achieve lower latency for mission critical traffic while maintaining compatibility with existing systems that use traditional TTI durations.
Data Source
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AI summary
The disclosure relates in some aspects to a scalable transmission time interval (TTI) and hybrid automatic repeat request (HARQ) design. The TTI is scalable to, for example, achieve latency and/or efficiency tradeoffs for different types of traffic (e.g., mission critical traffic versus traffic with more relaxed latency requirements). In the event a longer TTI is employed, various techniques are disclosed for ensuring a fast turn-around HARQ, thereby maintaining a high level of communication performance.