5G UE Reference-Time Handling After Radio Link Failure
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Solution Overview
Problem
Existing 5G networks face challenges in maintaining accurate synchronization of wireless devices with the 5G system clock during temporary radio link failures, which can lead to inaccuracies in time-sensitive network communications.
Innovation Solution
Implement methods for user equipment (UE) to synchronize timing by receiving timing adjustment values and declaring radio link failure when necessary, and for network nodes to retransmit these values or adjust timing based on UE indications, ensuring accurate propagation delay compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the network node transmits timing adjustment values periodically, then the UE can maintain synchronization during normal operation, but the UE cannot detect or respond to radio link failures that cause timing information loss
Solution Approach 1:
The patent implements a feedback mechanism where the UE monitors the reception of timing adjustment values and provides feedback about their successful receipt. The network node uses this feedback to determine whether to retransmit timing adjustment values, creating a closed-loop system that improves reliability while enabling failure detection.
Solution Approach 2:
The patent applies preliminary action by having the UE declare radio link failure conditions before complete synchronization loss occurs. The UE proactively notifies the network node when it detects that timing adjustment values are not being received, allowing the network to take corrective action before the synchronization issue fully impacts service.
2Measurement precision
If the UE continuously monitors for timing adjustment values, then synchronization accuracy is maintained, but the UE cannot efficiently handle temporary radio link outages without unnecessary reconnection attempts
Solution Approach 1:
The patent applies preliminary action by having the UE prepare and cache timing adjustment values before radio link failures occur. When a failure is detected, the UE can continue using cached timing information for a predetermined period, eliminating the need for immediate reconnection and improving productivity while maintaining timing accuracy.
Solution Approach 2:
The patent implements beforehand cushioning by establishing a predetermined period during which the UE can operate without receiving timing adjustment values. This cushioning period allows the UE to maintain synchronization using previously received timing information, preventing unnecessary reconnection attempts during temporary outages and improving overall system efficiency.
3Reliability
If the network node retransmits timing adjustment values upon failure indication, then synchronization reliability is improved, but the network complexity increases with additional retransmission logic
Solution Approach 1:
The patent uses feedback to simplify the retransmission logic. The network node receives feedback from the UE about timing adjustment value reception status and automatically determines when retransmission is needed. This feedback-based approach improves reliability while keeping the retransmission logic relatively simple and rule-based rather than complex.
Data Source
AI summary
Embodiments include methods for a user equipment (UE) to synchronize timing with a wireless network. Such methods include receiving, from a first node serving a first cell in the wireless network, a first message that includes an absolute reference time and a corresponding reference event within downlink, DL, transmissions by the first node; and determining whether the UE received, from the first node, a timing adjustment value from which the UE can estimate a propagation delay of the DL transmissions. Such methods include, based on determining that the UE did not receive the timing adjustment value, performing one of the following: transmitting, to the first node, an indication that the UE did not receive the timing adjustment value; or declaring radio link failure with respect to the first cell and establishing a connection with a second cell capable of providing the information included in the first message.