TDD Base Station Synchronization Degradation Handling
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Solution Overview
Problem
Mobile cellular networks in TDD mode face significant performance degradation due to cross-link interference caused by desynchronization between base stations, leading to service interruptions and increased interference when the link to an external synchronization clock is lost, resulting in shut-downs and reconnection issues.
Innovation Solution
Implementing targeted out-of-synchronisation measures, such as power reduction, TDD pattern adaptation, and adaptive modulation, to mitigate interference and maintain service even when synchronization is degraded or the external clock connection is lost, by continuously monitoring and adjusting synchronization deviations and applying specific measures based on calculated time differences and elapsed time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station maintains TDD mode operation after synchronization degradation, then service continuity is improved, but cross-link interference increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting TDD configuration parameters (uplink/downlink slot assignments) and transmission power levels based on the measured synchronization deviation. When synchronization degrades, the system modifies these parameters to reduce cross-link interference while maintaining service, directly resolving the contradiction between service continuity and interference reduction.
Solution Approach 2:
The system implements dynamics by continuously monitoring synchronization status and adaptively changing operational modes. Rather than a static shutdown threshold, the base station dynamically adjusts its behavior based on real-time synchronization quality, transitioning between different interference mitigation strategies to balance service continuity and interference control.
2Object-generated harmful factors
If the base station shuts down to avoid interference, then cross-link interference is reduced, but service interruption occurs
Solution Approach 1:
The patent implements continuity of useful action by maintaining base station operation and service provision even under synchronization degradation. Instead of shutting down, the system continues to provide service while applying interference mitigation measures, ensuring uninterrupted communication and avoiding the need for UE reconnection to other networks.
Solution Approach 2:
The system converts the harmful effect of synchronization degradation into a beneficial outcome by using the measured time deviation as a control parameter. The synchronization error, which would normally cause interference, is instead used to trigger adaptive measures that reduce interference while maintaining service, turning a problem into a solution.
3Reliability
If the base station uses internal oscillator after external clock failure, then service can be maintained temporarily, but synchronization accuracy degrades over time
Solution Approach 1:
The patent applies beforehand cushioning by implementing a graded response to synchronization degradation. Rather than allowing accuracy to degrade unchecked until shutdown, the system pre-defines threshold levels and progressively applies interference mitigation measures as accuracy degrades, cushioning the impact of prolonged operation with reduced synchronization quality.
Data Source
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AI summary
The present invention is directed to a method of handling a degradation of time synchronicity between base stations of a mobile cellular network, in particular supporting the 4G, 5G or any higher mobile communication standard, wherein the base stations perform Time Division Duplex (TDD) mode on a communication link with at least one User Equipment (UE), and wherein an internal time reference is required for control of the transmission time interval of the TDD mode, said internal time reference of the base stations is synchronized with an external synchronisation clock via a synchronisation link, characterised in that in case a link failure of the synchronisation link of a considered base station and/or a degradation of synchronicity of the internal time reference of the considered base station to any other base station, in particular to at least one adjacent base station, is detected, a TDD mode operation of the considered base station is maintained and at least one out-of-synchronisation measure is performed at the considered base station in order to mitigate a possible interference on surrounding cells caused by the degradation of synchronicity or the link failure of the considered base station.