Uband Reference Signal Transmission via Candidate Positions
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Solution Overview
Problem
The challenge in the LTE system is to ensure reliable reference signal measurement performance in Unlicensed Bands (Ubands) due to the indeterminate transmission occasions caused by the listening before talk (LBT) mechanism, which affects the Radio Resource Management (RRM) measurement performance of user equipment (UE).
Innovation Solution
The proposed solution involves extending the transmission occasion for reference signals in Unlicensed Bands by introducing multiple predetermined candidate transmission positions, allowing the eNB to sense and utilize idle channels for reliable reference signal transmission, and adaptively regulating the transmission density based on channel contention state and RRM measurement results to improve sending and receiving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LBT mechanism is used for reference signal transmission in Ubands, then channel access fairness is improved, but transmission occasion determinacy deteriorates
Solution Approach 1:
The patent introduces multiple candidate transmission positions with different periodicities (first periodicity for default positions, second periodicity for non-default positions). The eNB dynamically selects which candidate positions to use based on channel contention outcomes, allowing the transmission pattern to adapt between more frequent and less frequent occasions while maintaining determinacy within each pattern type.
2Reliability
If multiple candidate transmission positions are introduced, then reference signal transmission reliability is improved, but system complexity increases
Solution Approach 1:
The patent segments candidate transmission positions into two distinct groups: default candidate transmission positions with a first periodicity and non-default candidate transmission positions with a second periodicity. This segmentation allows the system to manage complexity by treating different position types separately, with the eNB selecting from predefined patterns rather than managing all positions uniformly.
Solution Approach 2:
The patent changes the periodicity parameter of transmission positions based on their type (default vs. non-default). Default positions use a first periodicity while non-default positions use a second periodicity. This parameter differentiation simplifies the management of multiple candidate positions by applying distinct rules to different groups, reducing overall system complexity while maintaining multiple transmission opportunities.
3Measurement precision
If transmission density is increased, then measurement performance is improved, but channel resource consumption increases
Solution Approach 1:
The patent enables dynamic adjustment of transmission density by allowing the eNB to adaptively select between default and non-default candidate transmission positions based on channel conditions and RRM measurement requirements. When better measurement performance is needed, more frequent non-default positions can be utilized; when resource conservation is prioritized, only default positions are used, creating a dynamic balance between measurement quality and resource consumption.
Data Source
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AI summary
An Unlicensed Band (Uband) reference signal sending method, receiving method and devices are provided, a Uband channel includes multiple predetermined candidate transmission positions for transmitting a reference signal, and each candidate transmission position is a transmission occasion for the reference signal. The sending method includes that: an Evolved Node B (eNB) senses whether the Uband channel is idle or not at all or part of the candidate transmission positions, and determines idle candidate transmission positions; and the eNB selects to send the reference signal to User Equipment (UE) at all or part of the idle candidate transmission positions according to historical Uband channel contention state information.