UE Packet-Based Synchronization After GNSS or Base Station Loss
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Solution Overview
Problem
In 5G New Radio (NR) systems, user equipment (UE) that lose connection with Global Navigation Satellite System (GNSS) or cellular base stations and lack sidelink synchronization capabilities experience timing and frequency errors, leading to communication disruptions, as they cannot maintain synchronization beyond a few seconds due to oscillator drift.
Innovation Solution
Unsynchronized UEs utilize reference signals from data packets received from synchronized UEs to perform autonomous timing adjustments, allowing them to maintain synchronization without relying on sidelink synchronization capabilities, by requesting and applying timing corrections from synchronized UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UEs rely on traditional synchronization mechanisms (GNSS, eNB, or sidelink SyncRef UEs), then synchronization accuracy is maintained, but UEs that lose connection or lack sidelink capabilities experience timing drift and communication failure
Solution Approach 1:
The UE performs autonomous timing adjustments by utilizing reference signals from received data packets to calculate and correct its own timing offset, without requiring external synchronization infrastructure. This self-service mechanism enables the UE to maintain synchronization independently when GNSS, eNB, or sidelink SyncRef UE connections are unavailable.
Solution Approach 2:
The synchronization mechanism is designed to work across multiple scenarios: connected to GNSS, connected to eNB, connected to sidelink SyncRef UE, or completely autonomous using reference signals from any data packet. This multi-functional approach allows the same timing adjustment mechanism to serve diverse synchronization needs regardless of connection status.
2Duration of action of stationary object
If UEs perform autonomous timing adjustments using reference signals from data packets, then communication continuity is maintained without external synchronization infrastructure, but timing precision may be affected by oscillator drift
Solution Approach 1:
The UE continuously monitors the timing offset between its transmitted packets and received reference signals, and adjusts its timing based on this feedback. This closed-loop mechanism compensates for oscillator drift over time by repeatedly measuring and correcting the timing offset, maintaining precision despite prolonged autonomous operation.
Solution Approach 2:
The UE is pre-configured with reference signal structures and timing offset calculation algorithms, allowing it to immediately begin autonomous synchronization upon losing external connections. This preliminary preparation enables rapid transition to independent operation without waiting for external synchronization sources.
3Reliability
If UEs continuously monitor and adjust timing using reference signals, then timing drift is compensated, but additional processing overhead and energy consumption occur
Solution Approach 1:
The UE performs timing offset measurements and adjustments periodically rather than continuously, using reference signals from received data packets at scheduled intervals. This periodic approach maintains timing accuracy by compensating for oscillator drift while reducing processing overhead and energy consumption compared to continuous monitoring.
Data Source
AI summary
Aspects of the present disclosure provide synchronization techniques for user equipment (UEs) that may be otherwise unable to support sidelink communication a synchronized UE and may have also lost global navigation satellite system (GNSS) and/or Evolved Node Base Stations (eNBs) as a synchronization source. In such instance, the unsynchronized UE may utilize reference signals (RS) from the data packets received from other UEs to track the timing and perform autonomous timing adjustments based thereon for synchronized packet transmission or reception.