S1 Handover Frequency Avoidance Signaling for Coexistence Interference
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Solution Overview
Problem
During S1 handover in mobile terminals, in-device coexistence interference issues arise due to the loss of frequency avoidance information, leading to increased coexistence interference and a 'ping-pong' effect where frequencies previously avoided are reused, causing interference.
Innovation Solution
A method and apparatus that provide signaling to the mobility management entity (MME) to indicate S1 handover and specify frequencies to be avoided, ensuring the target access point learns from the source access point's interference mitigation strategies to reduce coexistence interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If frequency separation is implemented to reduce coexistence interference, then coexistence interference is reduced, but frequency avoidance information is lost during S1 handover leading to increased interference post-handover
Solution Approach 1:
The source access point performs preliminary action by determining and storing frequency avoidance information before handover occurs. This information is then proactively transferred to the target access point through the MME during the handover signaling process, ensuring the target access point has the necessary frequency avoidance information before the mobile terminal connects to it, thus preventing coexistence interference from occurring in the first place.
Solution Approach 2:
The mobility management entity (MME) serves as an intermediary to transfer frequency avoidance information from the source access point to the target access point. The source access point sends the frequency avoidance information to the MME as part of the handover signaling, and the MME forwards this information to the target access point, ensuring the information is preserved and transferred during the S1 handover process.
2Adaptability or versatility
If mobile terminal switches to target access point during S1 handover, then mobility is enabled, but frequency avoidance information is not transferred causing ping-pong effect
Solution Approach 1:
The system performs preliminary action by preparing and transferring frequency avoidance information from the source access point to the target access point before the mobile terminal completes its connection to the target access point. This ensures that when the mobile terminal switches to the target access point, the frequency avoidance information is already in place, preventing the ping-pong effect and maintaining stable frequency usage patterns during mobility.
Solution Approach 2:
The system implements feedback by having the source access point determine frequency avoidance information based on observed coexistence interference conditions, then transfer this information to the target access point. The target access point uses this transferred information to maintain the same frequency avoidance strategy, creating a feedback loop that preserves the effectiveness of interference mitigation across handovers.
Data Source
AI summary
A method, apparatus, and computer program product are provided to reduce coexistence interference that may occur following a S1 handover. The method, apparatus and computer program product may provide the target access point with information regarding one or more frequencies to be avoided so as to reduce instances of coexistence interference that might otherwise occur following a SI handover.