Multi-mode Mobile Station Inter-Technology Handoff via Protocol Shims
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Solution Overview
Problem
The existing methods for inter-technology handoff in multi-mode mobile stations across different wireless communication networks result in delays due to shared components and interference, which is undesirable for real-time applications like VoIP, as they require minimizing total handoff time for seamless user experience.
Innovation Solution
A communication system that pre-establishes the registration state and authentication of a multi-mode mobile station with a target network before handoff by exchanging messaging between the source and target networks using shims in the protocol stack to tunnel signaling and bearer data, facilitating a seamless transition without interrupting the current connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If shared transmit or receive chains are used in a multi-mode mobile station to minimize cost, then device complexity and cost are reduced, but handoff delay increases due to alternating communication with source and target networks
Solution Approach 1:
The mobile station performs pre-registration and authentication with the target network before the actual handoff is triggered. This preliminary action prepares the target network in advance, so when handoff occurs, the mobile station can immediately switch to the target network without experiencing delays from alternating communication. The pre-established connection context eliminates the need for real-time negotiation during handoff, thus reducing handoff delay while maintaining shared hardware components.
2Loss of time
If separate complete implementations of each air interface technology are used in a multi-mode mobile station, then handoff can be accomplished without interaction between base stations and with minimal handoff delay, but device complexity and cost increase
Solution Approach 1:
The mobile station performs pre-registration and authentication with the target network before the actual handoff is triggered. This preliminary action prepares the target network in advance, so when handoff occurs, the mobile station can immediately switch to the target network without experiencing delays from alternating communication. The pre-established connection context eliminates the need for real-time negotiation during handoff, thus reducing handoff delay while maintaining shared hardware components.
Solution Approach 2:
A protocol stack with shims is introduced as an intermediary layer that enables communication between the mobile station and the target network through the source network. The shims intercept signaling messages and translate them into appropriate formats, allowing the mobile station to interact with the target network infrastructure without direct physical connection during the pre-registration phase. This intermediary mechanism enables complex inter-technology handoff procedures while using shared hardware components.
Data Source
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AI summary
A communication system (100) reduces set up time for an inter-technology handoff of a multi-mode mobile station (MS) (102) from a source network (110) and first radio frequency (RF) technology to a target network (120) and second RF technology by pre-establishing, prior to a handoff determination, a registration state and an authentication of the MS in association with the target network and second RF technology. In order to pre-establish the registration state and authentication, the MS exchanges messaging of the second RF technology with the second network via the source network and first RF technology. To facilitate the exchange, the MS includes shims (536, 540, 544) in a second protocol stack (530) associated with the second technology, which shims intercept second protocol stack signaling and redirect the intercepted signaling to a first protocol stack (510) of the MS, associated with the first technology, for tunneling to the source network.