Sidelink Synchronization Signaling with Dynamic DRX Timing

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Solution Overview

Problem

User equipment (UE) operating in sidelink communication may face challenges in maintaining synchronization when out of range of network infrastructure, leading to inefficient power consumption and delayed synchronization due to discontinuous reception modes.

Innovation Solution

UEs exchange information about sidelink synchronization and reduced reception of synchronization signals, adjusting their discontinuous reception modes to synchronize effectively, using modified master information blocks to convey synchronization status and timing adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If user equipment operates in discontinuous reception mode to save power, then power consumption is reduced, but synchronization delay increases

Engineering Contradiction:
Improvepower consumptionVSAvoidsynchronization delay
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The transmitting UE performs measurements during a predetermined evaluation time (e.g., 1.28s or 2.56s corresponding to 4 or 8 DRX cycles) before transmitting the sidelink synchronization signal. This preliminary evaluation allows the receiving UE to wake up only when necessary, reducing power consumption while maintaining timely synchronization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the evaluation time based on the DRX cycle length configured for the V2V terminal. When a longer DRX cycle is used, the evaluation time is extended proportionally, allowing the terminal to maintain synchronization efficiency while maximizing power savings during idle periods.

Inventive Principle:
Principle #15Dynamics

2Reliability

If user equipment transmits sidelink synchronization signals frequently to maintain synchronization, then synchronization reliability is improved, but power consumption increases

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system implements periodic sidelink synchronization signal transmission based on predetermined evaluation intervals (1.28s, 2.56s, or longer). The V2V terminal transmits synchronization signals only after completing measurements during these evaluation periods, creating a periodic rather than continuous transmission pattern that reduces power consumption while maintaining synchronization reliability.

Inventive Principle:
Principle #19Periodic action

3Measurement precision

If user equipment extends evaluation time for synchronization measurements, then synchronization accuracy is improved, but synchronization speed decreases

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidsynchronization speed
Core Design Contradiction:
Measurement precisionVSSpeed

Solution Approach 1:

The system allows dynamic adjustment of the evaluation time parameter based on the DRX cycle configuration. The evaluation time is set to 1.28s (4 DRX cycles) or 2.56s (8 DRX cycles) or even longer, enabling the terminal to achieve better synchronization accuracy by extending the measurement period while maintaining acceptable synchronization speed through optimized DRX cycle lengths.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4309434B1Method and apparatus for sidelink synchronization
Publication Date: 2025.08.13 NOKIA TECHNOLOGIES OY
  • EP4309434B1 patent drawingFigure 1~2
  • EP4309434B1 patent drawingFigure 3~4
  • EP4309434B1 patent drawingFigure 5~6

AI summary

There is provided a method comprising transmitting from a user equipment information about sidelink synchronization of the user equipment; and transmitting from the user equipment information about reduced reception of sidelink synchronization signals at the user equipment.