D2D Synchronization Source Selection in Partial Network Coverage
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Solution Overview
Problem
In device-to-device (D2D) communication, especially in partial and out-of-network coverage scenarios, existing synchronization procedures are inefficient, leading to increased UE power consumption and reduced wireless spectrum usage due to unnecessary transmission of D2D synchronization signals.
Innovation Solution
The proposed solution involves a synchronization source selection mechanism where eNBs designate UEs at coverage borders to transmit D2D synchronization signals based on RSRP reports, and UEs can autonomously decide to act as synchronization sources based on preconfigured criteria, minimizing the number of synchronization nodes and optimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UEs transmit D2D synchronization signals continuously to ensure synchronization coverage, then synchronization reliability is improved, but UE power consumption increases
Solution Approach 1:
The system enables UEs to autonomously determine whether to transmit D2D synchronization signals by evaluating preconfigured criteria such as coverage status and RSRP thresholds, without requiring continuous network control signaling. This self-service mechanism reduces unnecessary transmissions and power consumption while maintaining synchronization reliability.
Solution Approach 2:
The patent introduces dynamic parameter changes by adjusting transmission decisions based on RSRP measurements and threshold comparisons. UEs change their transmission state (on/off) based on whether measured RSRP falls below configured thresholds, optimizing power consumption while maintaining synchronization coverage.
2Area of stationary object
If multiple UEs transmit D2D synchronization signals to ensure coverage in partial network scenarios, then synchronization coverage is improved, but signaling overhead increases
Solution Approach 1:
The patent applies local quality by enabling D2D synchronization signal transmission only in specific local conditions where UEs are determined to be out of network coverage or at coverage edges. This is achieved through local evaluation of RSRP thresholds and coverage status, ensuring synchronization coverage is provided only where needed rather than universally.
Solution Approach 2:
Instead of requiring all UEs to transmit synchronization signals, the system implements partial action by enabling transmission only for UEs that meet specific criteria (e.g., RSRP below threshold, out-of-coverage status). This reduces the number of transmitting UEs to the minimum necessary for maintaining synchronization coverage.
3Measurement precision
If eNB manages all UEs to transmit D2D synchronization signals for synchronized transmission, then synchronization precision is improved, but device complexity increases
Solution Approach 1:
The system replaces complex centralized eNB management with autonomous UE-based synchronization source selection. Each UE independently evaluates preconfigured criteria and determines its own transmission status, eliminating the need for complex eNB-controlled management while maintaining synchronization precision through standardized decision-making rules.
Solution Approach 2:
The patent implements a standardized decision-making template that is copied and executed by each UE independently. The preconfigured criteria and evaluation logic are replicated across all UEs, ensuring consistent synchronization behavior without requiring complex centralized coordination.
Data Source
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AI summary
A user equipment (UE) is configured to scan for device-to-device synchronization sources based on scanning configuration information. The UE is configured to report detection of a device-to-device synchronization source to an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node B (eNB) in response to determining that the device-to-device synchronization source meets one or more reporting requirements of the scanning configuration information. The UE is configured to receive a communication from the eNB enabling the UE as a synchronization source and transmit signals to provide a synchronization reference to one or more in-range UEs including the device-to-device synchronization source.