Uplink Subframe Scheduling in Unlicensed Spectrum LBT
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Solution Overview
Problem
Existing signaling methods for listen-before-talk (LBT) parameters in LTE systems operating in unlicensed spectrum do not fully account for various use cases and inefficiencies, leading to suboptimal uplink transmission management and increased signaling overhead.
Innovation Solution
Efficient signaling of LBT parameters, specifically for Category 4 LBT schemes, is implemented by determining starting and stopping symbols for uplink data transmission based on indicated LBT types, allowing for flexible gap management between transmissions and reducing unnecessary signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing signaling methods for LBT parameters are used, then uplink transmissions can be scheduled in unlicensed spectrum, but signaling overhead increases and transmission efficiency decreases
Solution Approach 1:
The patent extracts only the essential LBT parameters needed for uplink transmission from the complete set of signaling parameters. By identifying and transmitting only the critical parameters (such as LBT type, contention window size, and minimum contention window size) rather than all possible parameters, the signaling overhead is significantly reduced while maintaining sufficient information for UEs to perform LBT procedures effectively.
Solution Approach 2:
The patent applies partial action by providing LBT parameter signaling only when and where it is truly necessary for uplink transmissions in unlicensed spectrum. Rather than continuously signaling all LBT parameters in every subframe, the system signals parameters selectively based on scheduling decisions and LBT requirements, reducing redundant signaling while ensuring parameters are available when needed for efficient uplink access.
2Adaptability or versatility
If LBT parameters are signaled for all use cases, then comprehensive coverage is achieved, but device complexity increases
Solution Approach 1:
The patent applies local quality by providing different levels of LBT parameter signaling针对不同 scenarios and UE capabilities. Rather than uniformly signaling all possible LBT parameters to all UEs in all situations, the system tailors the signaling to the specific use case, UE capability, and transmission requirements. This allows comprehensive coverage of different LBT scenarios while keeping individual UE processing complexity manageable by only processing the parameters relevant to their specific configuration and current transmission needs.
3Manufacturing precision
If gap management is rigidly controlled, then transmission timing is precise, but flexibility in handling LBT outcomes is reduced
Solution Approach 1:
The patent applies dynamics by making gap management flexible and adaptive rather than rigid and fixed. The system dynamically adjusts gap durations and timing based on LBT outcomes, channel conditions, and transmission requirements. UEs are provided with guidance on minimum and maximum gap durations but have the flexibility to adapt within this range based on actual LBT results and channel state, allowing precise timing control while maintaining adaptability to varying transmission scenarios.
Data Source
AI summary
According to some embodiments, a method for use in a user equipment (UE) of transmitting uplink data in unlicensed spectrum comprises receiving, from a network node, an uplink grant comprising an indication of one or more subframes to use for transmitting uplink data. Each subframe comprises a plurality of symbols. The method further comprises obtaining an indication of a listen-before-talk (LBT) type. The LBT type indicates a type of LBT procedure that the UE should perform before transmitting uplink data. The method further comprises determining, using the obtained LBT type, at least one of a starting symbol and a stopping symbol for transmitting uplink data, and transmitting uplink data according to at least one of the determined starting symbol and the determined stopping symbol.