Voice Call Handover via QBSS Load Monitoring
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Solution Overview
Problem
Dual-mode phones face challenges in maintaining high Quality of Service (QoS) for voice calls as network load increases, leading to degradation, especially when transitioning between Wi-Fi access points, and there is a need to automatically handover voice calls to alternate networks when QoS degrades.
Innovation Solution
Implementing a network monitor using IEEE 802.11e QoS Basic Service Set (QBSS) to track load metrics on wireless access points and send BSS Transition Management frames to idle voice clients when predetermined thresholds are exceeded, allowing them to transition to alternative networks or cellular connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If voice calls are maintained on Wi-Fi networks with increasing load, then network utilization is maximized, but Quality of Service (QoS) degrades due to bandwidth constraints, delay, jitter, and packet loss
Solution Approach 1:
The system performs preliminary actions by continuously monitoring QoS metrics (bandwidth, delay, jitter, packet loss) and predicting future QoS conditions. When degradation is anticipated before it significantly impacts voice calls, the system proactively triggers handover to alternative networks, preventing QoS deterioration while maintaining efficient Wi-Fi utilization.
Solution Approach 2:
The system implements continuous feedback loops by monitoring QoS metrics on Wi-Fi networks and using this information to dynamically control handover decisions. The feedback mechanism compares actual QoS performance against threshold values and automatically triggers network transitions when degradation is detected, ensuring reliable voice service while maximizing Wi-Fi utilization during good conditions.
2Adaptability or versatility
If manual handover between Wi-Fi access points is implemented, then users can transition to alternative networks, but the complexity of network management increases and seamless transitions are difficult to achieve
Solution Approach 1:
The system enables self-service by implementing automated QoS monitoring and handover trigger mechanisms that operate without user intervention. The network infrastructure itself monitors its performance metrics and automatically initiates handover processes when degradation is detected, eliminating the need for complex manual network management while providing seamless transitions for users.
Solution Approach 2:
The system performs preliminary actions by pre-evaluating alternative network conditions and preparing handover parameters before actual QoS degradation occurs. This includes monitoring candidate APs in advance and pre-configuring handover settings, which simplifies the execution phase and reduces management complexity during actual transitions.
3Reliability
If QoS monitoring and automatic handover triggers are implemented, then voice call quality is maintained, but the device complexity and processing requirements increase
Solution Approach 1:
The system extracts and separates the complex QoS monitoring and handover control functions into dedicated network infrastructure components rather than burdening end devices. By placing the monitoring intelligence in the network and using simple trigger-based handover signals, the system maintains high voice call quality while minimizing the complexity burden on user devices.
Solution Approach 2:
The system performs preliminary QoS analysis and handover preparation in the network infrastructure before involving user devices. This allows complex monitoring and decision-making to occur centrally, with user devices receiving simplified handover commands, thereby maintaining voice call quality while reducing device complexity.
Data Source
AI summary
Transitioning voice clients among network resources. A network monitor using IEEE 802.11e QBSS Load IE elements monitors the load on one or more wireless access points. When the load on an access point, as reported in the QBSS Load Element IE exceeds a predetermined threshold, the network monitor sends a message to that AP which causes the AP to send BSS Transition Management Request frames to all connected voice clients which are currently idle. The information passed to the AP and then to the client may include one or more neighboring APs with capacity.