Uplink Transmission Scheduling Outside TxOP in Unlicensed Spectrum
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Solution Overview
Problem
Current LTE systems face limitations in spectral efficiency and data rate enhancement due to the scarcity of licensed spectrum, particularly in the low frequency band, and require improved uplink transmission performance in unlicensed spectrum scenarios.
Innovation Solution
The technology enables user equipment (UE) to perform uplink transmissions outside a transmission opportunity (TxOP) by modifying the listen-before-talk (LBT) procedure, allowing for enhanced physical uplink shared channel (PUSCH) and control channel (PUCCH) transmissions, and signaling LBT parameters from an eNodeB to a UE for efficient operation in unlicensed spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If uplink transmissions are performed outside TxOP in unlicensed spectrum, then spectral efficiency and data rate are improved, but LBT procedure complexity increases
Solution Approach 1:
The patent changes the parameters of the LBT procedure by introducing different LBT category types (Category 1, 2, 3, 4) with varying levels of channel access complexity. The eNodeB can dynamically select and signal appropriate LBT parameters to the UE based on channel conditions and traffic requirements, allowing simpler LBT procedures when appropriate while maintaining spectral efficiency through flexible uplink transmission scheduling outside TxOP.
2Quantity of substance
If uplink transmissions are scheduled outside TxOP, then system bandwidth is expanded, but coexistence fairness with incumbent systems may be compromised
Solution Approach 1:
The patent implements dynamic LBT parameter selection where the eNodeB adapts the LBT category and parameters based on real-time channel conditions, incumbent system activity, and traffic demands. This dynamic adjustment allows the system to expand bandwidth utilization through outside-TxOP transmissions while maintaining fair coexistence by selecting appropriate LBT strictness levels to protect incumbent systems when necessary.
Solution Approach 2:
By changing LBT parameters (contention window size, defer period, LBT category) based on channel conditions and incumbent system presence, the system can flexibly control its impact on coexistence fairness while utilizing unlicensed spectrum resources for bandwidth expansion.
3Productivity
If LBT parameters are signaled from eNodeB to UE, then uplink transmission efficiency is improved, but signaling overhead increases
Solution Approach 1:
The patent makes the uplink grant message multi-functional by embedding both scheduling information and LBT parameter configuration in a single signaling message. This allows the eNodeB to efficiently convey multiple pieces of information (resource allocation, modulation scheme, LBT category, contention window size) simultaneously, improving uplink transmission efficiency while minimizing signaling overhead through message consolidation.
Data Source
AI summary
transmissions outside a transmission opportunity (TxOP) is disclosed. The UE can process an uplink (UL) opportunity received from an eNodeB during a defined transmission opportunity (TxOP). The UL opportunity can schedule UL information to be transmitted from the UE on one or more UL subframes that are outside the defined TxOP. The UE can initiate a listen-before-talk (LBT) procedure to be performed before the UL information is transmitted from the UE on the one or more UL subframes that are outside the defined TxOP. The UE can process the UL information for transmission to the eNodeB on the one or more UL subframes located outside the defined TxOP.