ULL Data Bearer Latency Reduction in Unlicensed LTE
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Solution Overview
Problem
Current LTE technologies face challenges in reducing transmission latency, especially in unlicensed spectrum, which is critical for supporting high-bandwidth applications like high-resolution graphics and video on mobile devices.
Innovation Solution
The implementation of listen-before-talk (LBT) access rules for establishing dedicated ultra-low latency (ULL) data bearers, allowing faster channel access priority than control and signal traffic, along with techniques like mapping ULL traffic to high priority classes, updating contention windows, and managing discontinuous reception (DRX) to reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional LTE channel access procedures are used in unlicensed spectrum, then control and signal traffic can be transmitted reliably, but transmission latency increases due to lower access priority
Solution Approach 1:
The patent segments channel access procedures into different priority classes, creating separate access paths for ULL data traffic (higher priority) and control/signal traffic (lower priority). This segmentation allows ULL traffic to bypass the conventional lower-priority access procedure, reducing latency while maintaining reliable access for control functions through their dedicated procedure.
2Loss of time
If faster channel access priority is allocated to ULL data traffic, then transmission latency is reduced, but channel access contention increases
Solution Approach 1:
The patent changes the LBT parameters (contention window size, defer period, priority level) specifically for ULL data traffic compared to conventional control/signal traffic. By adjusting these parameters, ULL traffic achieves faster access with optimized contention characteristics, reducing both latency and excessive contention through parameter optimization rather than simple priority escalation.
Data Source
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AI summary
Methods and apparatuses for wireless communication in a wireless communication system are described. An uplink grant is ignored and scheduled uplink transmissions are cancelled for the transmission of ultra low latency (ULL) data in a downlink subframe of a channel in a portion of an unlicensed frequency spectrum.