Adaptive Shortened Transmission Time Interval for Wireless Latency Reduction
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in packet data latency, which affects throughput and user performance due to fixed time transmission intervals (TTIs), leading to increased round-trip times and suboptimal radio-resource utilization.
Innovation Solution
Implementing adaptive shortened time transmission intervals (S-TTIs) that can vary dynamically based on user equipment (UE) and cell-specific information, allowing for flexible scheduling and trade-offs between latency and overhead, enabling faster TCP packet acknowledgment and improved downlink throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If fixed time transmission intervals (TTIs) are used, then system stability and simplicity are maintained, but packet data latency increases and throughput decreases
Solution Approach 1:
The patent implements dynamic TTI length adjustment by introducing multiple TTI length configurations (first TTI length and second TTI length) that can be selectively applied based on traffic conditions. The network device dynamically switches between different TTI lengths to optimize latency for urgent data while maintaining standard operation for normal traffic, directly resolving the contradiction between time loss and adaptability.
Solution Approach 2:
The patent changes the TTI length parameter from a fixed value to a variable parameter that can take different configurations. By defining multiple TTI length options and selectively applying them based on data urgency and traffic conditions, the system transforms the static TTI parameter into a dynamic one that adapts to different operational requirements, reducing latency without sacrificing system stability.
2Productivity
If shorter TTI lengths are used, then round-trip time is reduced and throughput is improved, but scheduling complexity and overhead increase
Solution Approach 1:
The patent segments the data traffic into different categories (urgent data requiring short TTI and normal data using standard TTI) and applies different TTI length configurations to each segment. This segmentation allows the system to use shorter TTIs only when necessary for high throughput, while maintaining standard TTIs for other traffic, thereby improving productivity without excessively increasing scheduling complexity across the entire system.
Solution Approach 2:
The patent implements dynamic switching between different TTI length configurations based on real-time traffic conditions and data urgency. The network device adjusts the TTI length dynamically rather than using a fixed short TTI for all transmissions, which reduces the average round-trip time and improves throughput while managing scheduling complexity through condition-based adaptation rather than continuous complex scheduling.
3Loss of time
If adaptive S-TTIs are implemented, then latency is reduced and user perceived throughput is enhanced, but control overhead and signaling requirements increase
Solution Approach 1:
The patent applies partial action by using shortened TTI configurations only for specific urgent data transmissions rather than for all traffic. The network device selectively applies the first TTI length configuration only when latency reduction is necessary, while using the second TTI length configuration for normal traffic. This partial application reduces control overhead and signaling requirements compared to universally applying adaptive S-TTIs, while still achieving latency reduction for time-critical data.
Data Source
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AI summary
A network device (e.g., an evolved NodeB (eNB), or other user equipment (UE)) can generate or process a shortened transmission time interval (S-TTI). Joint operations between an eNB and a UE can occur for a selection of a configuration of the S-TTI. The number of symbols can be dynamically modified and vary from among UEs based on UE-specific information and cell-specific information. The S-TTIs can be shorter than standard TTIs that enable data transmission or reception within a cell.