FDD Shortened TTI Timing Association for Latency Reduction
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Solution Overview
Problem
Current wireless communication systems face limitations in flexibility and efficiency, particularly in managing different sizes of transmission time intervals (TTIs) for downlink and uplink channels, which affects latency and processing delays in HARQ-ACK reporting and PUSCH scheduling.
Innovation Solution
The implementation of frequency-division duplex (FDD) transmission time interval (TTI) systems that allow for independently configured shortened TTI sizes for downlink and uplink channels, with flexible association timing based on the larger TTI size, enabling reduced latency through scaled processing delays and adjusted HARQ-ACK feedback and PUSCH scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If shortened TTI sizes are configured for downlink and uplink channels, then latency is reduced, but processing delays and association timing complexity increase
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting TTI sizes for downlink and uplink channels based on traffic conditions and service requirements. The system configures different TTI lengths (e.g., 1ms, 0.5ms, 0.25ms) to optimize latency while managing processing complexity through standardized timing relationships.
Solution Approach 2:
The system implements dynamic TTI configuration where the base station can independently set different shortened TTI sizes for downlink and uplink channels. This dynamic adaptation allows the system to respond to varying traffic demands while maintaining manageable association timing through defined scaling rules.
2Adaptability or versatility
If different TTI sizes are configured for downlink and uplink channels, then flexibility is improved, but system complexity increases
Solution Approach 1:
The patent applies local quality by allowing different TTI sizes to be configured for specific downlink and uplink channels based on local traffic requirements. Each channel can have optimized TTI configuration independent of others, providing granular control over flexibility while managing overall system complexity through localized adjustments.
Solution Approach 2:
The system segments the TTI configuration into independent downlink and uplink components, each with its own size parameters. This segmentation allows flexible configuration of each direction separately while simplifying the overall system design by treating them as independent configurable elements with standardized association rules.
3Productivity
If TTI sizes are optimized for specific channels, then channel efficiency is improved, but overall system coordination complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining standardized association timing relationships between downlink and uplink TTIs. The base station configures TTI sizes and their timing associations in advance based on expected traffic patterns, allowing channels to operate efficiently with pre-coordinated timing rather than requiring complex real-time coordination.
Data Source
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AI summary
A user equipment (UE) is described. The UE is configured to determine a duplex method of a serving cell. The UE is also configured to determine that shortened transmission time interval (sTTI) is configured on at least one of one or more downlink subframes or one or more uplink subframes. The UE is further configured to determine a sTTI downlink size and a sTTi uplink size. The UE is additionally configured to determine an association timing reference sTTI size based on the sTTI downlink size and the sTTI uplink size. The UE is also configured to determine a sTTI PDSCH HARQ-ACK transmission timing for the serving cell. The UE is further configured to determine a sTTI PUSCH scheduling timing for the serving cell. The UE is additionally configured to determine a sTTI PUSCH HARQ-ACK transmission timing for the serving cell.