Uplink Reference Signal Transmission Coordination in Unlicensed Bands
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Solution Overview
Problem
In LTE/LTE-A systems operating in unlicensed bands, there is a risk of significant cross-interference due to the lack of synchronization and coordination between different operators' radio access points, making it challenging to control uplink transmission and listening operations effectively.
Innovation Solution
A user terminal with a transmission section for uplink shared channels, control channels, and reference signals, where the control section manages these transmissions based on listening results, ensuring that uplink reference signals are transmitted only when the uplink shared channel and control channel are active, and sharing LBT timings to reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If uplink reference signals are transmitted independently without coordination with uplink shared channel and control channel, then reference signal transmission flexibility is improved, but cross-interference with other systems increases
Solution Approach 1:
The patent merges the transmission control of uplink reference signals with the control of uplink shared channels and control channels. By coordinating these transmissions under unified listening-based control, the system reduces cross-interference while maintaining operational flexibility through integrated resource management.
Solution Approach 2:
The patent implements preliminary listening before uplink transmission to detect channel availability and prevent interference. This preliminary action ensures that reference signals, shared channels, and control channels are only transmitted when the channel is clear, thereby reducing cross-interference with other systems operating in the same frequency band.
2Object-affected harmful factors
If listening operations are performed before every uplink transmission, then interference control is improved, but power consumption increases
Solution Approach 1:
The patent combines multiple listening operations into a single coordinated listening event when uplink reference signals and other uplink channels are transmitted together. This merging reduces the total number of separate listening operations, thereby controlling interference effectively while reducing power consumption compared to performing independent listening before each transmission type.
Solution Approach 2:
The patent applies listening selectively rather than continuously - performing listening operations only when uplink transmissions are scheduled rather than before every possible transmission. This partial action approach maintains adequate interference control while avoiding the excessive power consumption that would result from continuous or overly frequent listening operations.
3Object-affected harmful factors
If uplink transmissions are coordinated based on listening results, then cross-interference is reduced, but transmission complexity increases
Solution Approach 1:
The patent merges the control logic for multiple uplink channel transmissions into a unified coordination mechanism based on listening results. By handling reference signals, shared channels, and control channels through a single coordinated framework rather than separate independent controls, the system reduces cross-interference while managing complexity through consolidation rather than multiplication of control mechanisms.
Data Source
AI summary
The present invention is designed so as to carry out the listening operation that accompanies UL transmission and/or UL transmission adequately when UL transmission is controlled based on the result of listening. The present invention provides a transmission section that transmits an uplink shared channel, an uplink control channel and an uplink reference signal, and a control section that controls the transmission of the uplink shared channel, the uplink control channel and/or the uplink reference signal based on the result of listening in the uplink, and, when the uplink reference signal is configured to be transmitted in a subframe in which the uplink shared channel and/or the uplink control channel are transmitted, the control section controls the transmission of the uplink reference signal based on the result of listening that is executed before the uplink shared channel and/or the uplink control channel are transmitted.