Sidelink DMRS Positioning for Variable LBT Success in Unlicensed Bands
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Solution Overview
Problem
Existing sidelink communication in unlicensed bands requires optimization of listen before talk (LBT) operations and demodulation reference signal (DMRS) configurations to enhance communication efficiency.
Innovation Solution
A method and apparatus for configuring DMRS positions based on the success of LBT operations within a slot, where DMRS positions vary depending on the symbol where LBT succeeds, and DMRS configuration information is received from a base station to adapt to different slot types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DMRS positions are configured based on fixed slot structure, then configuration simplicity is maintained, but communication efficiency deteriorates due to LBT operation variability in unlicensed bands
Solution Approach 1:
The patent applies dynamics by making DMRS positions variable based on the actual LBT success position within the slot. Instead of using fixed DMRS positions, the configuration adapts dynamically to the random backoff outcome, allowing the system to optimize communication efficiency for each transmission opportunity while managing the complexity through predefined mapping rules.
Solution Approach 2:
The patent changes the parameter of DMRS position indexing based on the LBT success position. By adjusting the starting index and offset of DMRS positions according to where LBT succeeded within the slot, the system optimizes resource utilization and communication efficiency without requiring completely new configuration mechanisms.
2Reliability
If LBT operation uses random backoff, then channel access fairness is improved, but transmission timing uncertainty increases
Solution Approach 1:
The patent applies preliminary action by pre-defining multiple DMRS position configurations corresponding to different possible LBT success positions. This allows the system to quickly select the appropriate configuration after LBT succeeds, reducing the time loss from timing uncertainty while maintaining the fairness benefits of random backoff.
Solution Approach 2:
The system dynamically adjusts DMRS positions based on the actual LBT success position, transforming the timing uncertainty into a controlled variable. This dynamic adaptation allows the system to maintain reliability through fair channel access while minimizing the impact of timing variations on communication performance.
3Productivity
If DMRS positions are adjusted to match LBT success position, then resource utilization is improved, but configuration complexity increases
Solution Approach 1:
The patent changes DMRS position parameters (index and offset) based on LBT success position to improve resource utilization. By systematically adjusting these parameters according to the random backoff outcome, the system optimizes resource usage while managing complexity through standardized parameter mapping rules.
Solution Approach 2:
The patent creates a universal DMRS configuration mechanism that handles multiple LBT success positions through a unified approach. The same configuration rules and mapping relationships apply regardless of where LBT succeeds within the slot, making the system multi-functional while avoiding the need for separate configuration mechanisms for each scenario.
Data Source
AI summary
A method and apparatus for configuration of a DMRS considering an LBT operation in sidelink communication in an unlicensed band are disclosed. The method for first UE comprises the steps of: performing an LBT operation for transmission of a channel in an unlicensed band; identifying, within a first slot, one or more DMRS locations on the basis of a first location of a symbol in which the LBT operation is successful; transmitting the channel to second UE after the LBT operation is successful; and transmitting a DMRS to the second UE at the one or more DMRS locations.