Lite Sidelink Sync Signal Demand for Power Efficiency
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Solution Overview
Problem
Current sidelink synchronization signal block (S-SSB) transmissions in 5G NR are resource inefficient and power consuming, particularly for power-limited sidelink user equipments (UEs) and vehicles out of network coverage, leading to increased latency and reduced communication efficiency in vehicle-to-everything (V2X) communications.
Innovation Solution
The implementation of a 'lite' S-SSB transmission method that includes only a sidelink primary synchronization signal (S-PSS) and/or sidelink secondary synchronization signal (S-SSS) without a physical sidelink broadcast channel (PSBCH), allowing receiving UEs to demand additional SL-SSs from transmitting UEs on indicated resources, which can include pre-configured or dynamically indicated resources, and adjusting transmit power based on UE behavior and coverage status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional S-SSB transmission with PSBCH is used, then synchronization information is complete, but power consumption and system overhead increase
Solution Approach 1:
The S-SSB transmission is segmented into two parts: a lite S-SSB containing only S-PSS and S-SSS for basic synchronization, and an optional PSBCH for additional system information. This segmentation allows receiving UEs to perform initial synchronization with minimal power consumption, while only requesting PSBCH when actually needed, thus resolving the contradiction between synchronization completeness and power consumption.
Solution Approach 2:
Instead of transmitting the complete S-SSB with PSBCH every time, the system transmits only the partial lite S-SSB (S-PSS and S-SSS) as a baseline. The PSBCH is transmitted partially or excessively only when requested by receiving UEs, reducing overall power consumption while maintaining the capability for complete synchronization when needed.
2Reliability
If traditional S-SSB transmission with PSBCH is used, then synchronization information is complete, but resource efficiency decreases
Solution Approach 1:
The S-SSB transmission is segmented into a lite version (S-PSS and S-SSS only) and an extended version with PSBCH. This segmentation improves resource efficiency by allowing the lite version to be transmitted more frequently or to more UEs without consuming excessive resources, while the PSBCH is transmitted only when needed, thus resolving the contradiction between synchronization completeness and resource efficiency.
Solution Approach 2:
The system transmits partial synchronization information (lite S-SSB) as a baseline to multiple UEs efficiently, and only transmits the complete information with PSBCH to specific UEs that request it. This partial action approach improves overall resource efficiency while maintaining the ability to provide complete synchronization when needed.
3Use of energy by moving object
If lite S-SSB without PSBCH is transmitted, then power consumption is reduced, but additional signaling overhead is required
Solution Approach 1:
The transmitting UE pre-configures resource indicators for potential PSBCH transmissions and pre-establishes the lite S-SSB structure. When a receiving UE needs additional information, the transmitting UE can quickly respond using the pre-configured resources, reducing the signaling overhead compared to establishing new transmission parameters dynamically. This preliminary action resolves the contradiction between power reduction and signaling overhead.
4Use of energy by moving object
If adaptive transmit power is used based on UE behavior, then power efficiency is improved, but complexity of power management increases
Solution Approach 1:
The system changes the transmit power parameter adaptively based on UE behavior patterns, coverage status, and synchronization needs. By dynamically adjusting this single critical parameter rather than redesigning the entire power management system, the patent achieves improved power efficiency while keeping the complexity increase manageable. The parameter changes are based on observable UE behaviors rather than complex predictive models.
Data Source
AI summary
A method of wireless communications by a receiving sidelink user equipment includes detecting a lite sidelink synchronization signal (SL-SS) transmitted by a transmitting sidelink UE. The lite SL-SS may have a pattern with a reduced number of physical sidelink broadcast channel (PSBCH) symbols. The method also includes transmitting a demand requesting additional SL-SSs from the transmitting sidelink UE on indicated resources. Another method includes receiving a demand for additional sidelink synchronization signals (SL-SSs) from a receiving sidelink UE. This method further includes transmitting the additional SL-SSs in response to the demand.