PS to CS Domain Handoff via Interworking Gateway
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Solution Overview
Problem
In communication networks with both Circuit Switching (CS) and Packet Switching (PS) domains, handoff from the PS domain to the CS domain is complex, requiring modifications to existing CS domain networks and simulation of CS domain services, which complicates resource management and increases costs.
Innovation Solution
A method for handoff from the PS domain to the CS domain involving a Mobile Station (MS) obtaining a handoff number and initiating a CS domain session, with an Interworking Gateway (IWGW) associating the session and facilitating the air interface handoff, without modifying existing CS domain networks or simulating CS domain services, thus simplifying routing and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the A16 interface is added to the BSC in the CS network to implement handoff, then handoff functionality is achieved, but network complexity and cost increase
Solution Approach 1:
The patent introduces a handoff entity control layer in the PS domain that acts as an intermediary to simulate the CS domain service. This mediator translates PS domain calls into simulated CS domain calls, enabling handoff without modifying the existing CS network infrastructure. The handoff entity control layer forwards calls to the CS domain through existing interfaces, avoiding the need to add new A16 interfaces to BSC.
2Adaptability or versatility
If the handoff entity control layer simulates the original CS domain service, then handoff is enabled, but resource consumption and cost increase
Solution Approach 1:
The handoff entity control layer creates a virtual copy of the CS domain service environment within the PS domain. Instead of physically replicating CS network elements, it implements a software-based simulation that reproduces CS domain calling behavior. This allows PS domain devices to interact with CS domain services through a virtual interface, reducing the need for physical resource duplication.
3Adaptability or versatility
If existing CS domain networks are modified to support handoff, then handoff is achieved, but network stability and reliability deteriorate
Solution Approach 1:
The patent performs all necessary handoff preparation and service simulation actions in advance within the PS domain, before actual handoff is needed. The handoff entity control layer pre-establishes the virtual CS domain environment and prepares translation rules, so that when handoff is triggered, the existing CS network can be accessed through pre-configured interfaces without requiring real-time modifications or adjustments to the stable CS infrastructure.
Data Source
AI summary
The present invention discloses a method for handoff from a PS domain to a CS domain, including: the MS obtaining a handoff number and initiating a CS domain session request by taking the handoff number as a called number; a network side associating the CS domain session request to an original session of the MS and notifying the MS to finish an air interface handoff; the MS notifying the network side to finish a network side handoff. The present invention also discloses a CS domain access network simulating entity, a PS domain access network and an MS thereof. By adopting the solution, it is not necessary to modify existing network cells in the CS domain network, and the routing process is simplified. It is not necessary for handoff control layer entities to simulate original services of the CS domain. There is no new requirement for functions of the MGCF entity.