Proactive Handoff Policy Function for QoS Preservation
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Solution Overview
Problem
Current handoff schemes between wireless access networks fail to preserve the Quality of Service (QoS) constraints for ongoing IP service sessions, leading to adverse effects on user experience and network resource efficiency in next-generation wireless access networks.
Innovation Solution
An enhanced handoff scheme that monitors mobile device and network conditions to proactively initiate a handoff operation, using a policy function to select an appropriate access gateway that maintains QoS constraints by ordering a list of preferred access networks based on received signal quality, bandwidth, latency, and other indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If typical handoff schemes between wireless access networks are used, then handoff operation can be performed, but QoS constraints for ongoing IP service sessions are not preserved
Solution Approach 1:
The patent applies preliminary action by establishing a list of preferred access networks in advance, ordered by their ability to satisfy QoS constraints. The policy function pre-evaluates and ranks access networks based on QoS capabilities before handoff is needed, so that when handoff is required, the system can quickly select from the pre-ordered list rather than evaluating all networks in real-time, thus preserving QoS while managing complexity.
Solution Approach 2:
The patent introduces a policy function as an intermediary between the mobile device and access networks. This policy function receives QoS constraints from the mobile device, evaluates access network conditions, and makes handoff decisions based on QoS satisfaction. The policy function acts as a mediator that centralizes the complex QoS evaluation logic, separating it from the mobile device and access networks, thereby preserving QoS constraints while managing system complexity.
2Reliability
If proactive handoff monitoring is implemented to preserve QoS constraints, then seamless IP multimedia service delivery is achieved, but system complexity increases
Solution Approach 1:
The patent implements feedback mechanisms where the policy function continuously monitors access network conditions and mobile device status, compares current state against QoS requirements, and triggers handoff decisions when QoS constraints are no longer satisfied. The system receives feedback about network conditions and service quality, and uses this feedback to make proactive handoff decisions, ensuring seamless service delivery while managing complexity through automated closed-loop control.
3Reliability
If handoff decisions are based on multiple parameters (signal quality, bandwidth, latency), then QoS preservation is improved, but decision-making complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically evaluating multiple network parameters (signal quality, bandwidth, latency) and transforming them into a unified QoS satisfaction assessment. The policy function monitors changes in these parameters and determines whether they collectively satisfy QoS constraints. By changing the state of multiple parameters and evaluating their combined effect, the system makes informed handoff decisions that preserve QoS while managing decision complexity through systematic parameter evaluation.
Data Source
AI summary
A system and method are described whereby an enhanced handoff scheme provides for monitoring of mobile device conditions and network conditions associated with a current access network attachment, as well as with a plurality of access networks on a preferred access network list, to proactively initiate a handoff operation, thereby preserving the QoS constraints necessary for seamless delivery of IP multimedia services. In an embodiment, each of the plurality of access networks is connected to an IMS core network, whereby a policy function receives quality of service constraints associated with the launched application from the mobile device and orders a list of preferred access networks accordingly. Preferably, the policy function selects an appropriate access gateway associated with a target access network based at least in part on the mobile device conditions reported by the mobile device and the access network conditions monitored by the policy function.