Dual-Mode Handoff Threshold Adaptation
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Solution Overview
Problem
Current technologies lack effective mechanisms for seamless vertical hand-off of communication sessions, such as voice calls, between wireless local area networks (WLANs) and cellular networks, particularly in dual-mode mobile devices, leading to suboptimal switching decisions based on signal strength and failure rates.
Innovation Solution
A method is implemented in dual-mode mobile devices to monitor signal strength thresholds and adjust failure and success rates for switching between WLANs and cellular networks, dynamically adjusting these thresholds based on historical data to optimize hand-off decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If signal strength threshold is used for hand-off decision, then switching between WLAN and cellular network can be automated, but suboptimal switching decisions occur leading to poor reliability
Solution Approach 1:
The patent implements feedback mechanisms where hand-off decisions are continuously evaluated based on actual outcomes. Success and failure rates are tracked for each access point, and these feedback metrics are used to dynamically adjust future hand-off decisions. The system learns from past hand-off results to improve subsequent switching reliability while maintaining automated operation.
Solution Approach 2:
The system performs preliminary evaluations by monitoring signal strength thresholds and historical hand-off performance before making switching decisions. By pre-assessing access point quality metrics and maintaining records of past hand-off outcomes, the system prepares optimal switching decisions in advance, improving reliability while keeping the automation process efficient.
2Device complexity
If fixed signal strength threshold is used for switching, then device complexity is reduced, but adaptability to different network conditions deteriorates
Solution Approach 1:
The patent transforms fixed thresholds into dynamic, adaptive parameters. Signal strength thresholds and hand-off decisions are no longer static but continuously adjust based on historical performance data, success rates, and failure rates specific to each access point. This dynamic approach enables the system to adapt to varying network conditions while maintaining manageable device complexity through automated learning.
Solution Approach 2:
The system changes parameters dynamically by modifying signal strength thresholds and hand-off criteria based on observed network conditions and historical outcomes. Each access point develops customized parameter sets through accumulated experience, allowing the device to adapt to different network environments without requiring complex manual configuration or increasing overall system complexity.
3Speed
If hand-off attempts are made based on current signal strength, then switching speed is improved, but failure rate increases due to lack of historical context
Solution Approach 1:
The system performs preliminary assessments by evaluating historical hand-off data and access point performance metrics before initiating switching attempts. By pre-analyzing success rates, failure patterns, and signal strength histories, the system prepares informed hand-off decisions that maintain quick switching speed while reducing failure rates through experience-based optimization.
Solution Approach 2:
The patent implements feedback loops where each hand-off attempt's outcome is recorded and used to refine future decisions. The system learns from past successes and failures, adjusting hand-off timing, threshold selections, and access point preferences based on accumulated experience. This feedback mechanism enables fast switching while continuously improving success rates through adaptive learning.
Data Source
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AI summary
To handle a communication session at a wireless mobile communications device, after receiving an indication of current signal strength of an access point for a wireless local area network ("WLAN") a signal strength threshold associated with the access point is retrieved. If the communication session is currently carried by a cellular network and the current signal strength exceeds the signal strength threshold, the communication session is switched from the cellular network to the WLAN. A metric is then adjusted based on timing of the switch relative to any switch of the communication session from the WLAN to the cellular network over a preceding time window associated with the access point. Based on the metric, the signal strength threshold associated with the access point is selectively adjusted. If, on the other hand, the communication session is currently carried by the WLAN and the current signal strength is below the signal strength threshold, an attempt is made to switch the communication session from the WLAN to the cellular network and a metric associated with the access point is adjusted based on whether or not the switch failed. Based on this second metric, the signal strength threshold associated with said access point is adjusted.