Soft-Switch WAC Implementation via Number Transformation
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Solution Overview
Problem
Current methods for implementing Wide Area Centrex (WAC) require significant changes to existing network infrastructure, including software and hardware modifications, which are costly and difficult to implement across different switch manufacturers and versions, and do not fully utilize existing network techniques and facilities.
Innovation Solution
The implementation of WAC using a soft-switch that routes calls based on long and short number transformations, without requiring changes to existing switches, by saving the corresponding relationship between long and short numbers in the soft-switch or an external database, allowing calls to be routed efficiently across PSTN/PLMN and NGN users using standard ISUP/TUP protocols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If WAC is implemented through IN with multiple cities covered by intelligent network, then users can call each other with short numbers across regions, but the system complexity and cost increase due to requiring SCP, SSP, and extensive number transformation tables
Solution Approach 1:
The patent extracts the number transformation function from the complex IN system (SCP/SSP) and relocates it to the access switch (LS). The LS directly stores and transforms long numbers to short numbers based on a configured correspondence relationship, eliminating the need for intelligent network components while achieving the same cross-region short number calling capability.
Solution Approach 2:
The patent introduces an intermediary configuration mechanism where the access switch LS acts as a mediator between users and the number transformation function. The LS stores a correspondence relationship table that maps long numbers to short numbers, and automatically performs transformation during call setup, serving as an intermediary that simplifies the overall system architecture.
2Productivity
If WAC is implemented by distributing number memorization across multiple switches, then each switch can handle local transformations, but the device complexity and maintenance difficulty increase due to requiring consistent data synchronization across all switches
Solution Approach 1:
The patent segments the number transformation function to be performed locally at each access switch LS that has WAC users. Each LS independently stores and applies the correspondence relationship between long and short numbers for its own users, eliminating the need for complex inter-switch data synchronization while maintaining distributed call handling capability.
3Adaptability or versatility
If existing switches are modified with software or hardware changes to support WAC, then WAC service can be provided, but the ease of manufacture and deployment deteriorates due to compatibility issues across different switch manufacturers and versions
Solution Approach 1:
The patent makes the access switch LS universal by enabling it to perform multiple functions: traditional call switching and WAC number transformation. The LS uses its existing number analysis capability to determine whether a dialed number is a long or short number, and automatically performs appropriate transformation based on the correspondence relationship, eliminating the need for manufacturer-specific modifications.
4Adaptability or versatility
If long number and short number correspondence is stored in SCP, then centralized management is achieved, but the loss of time and system resources increase due to heavy workload and high cost at the intelligent network level
Solution Approach 1:
The patent performs preliminary action by pre-configuring the correspondence relationship between long and short numbers directly in the access switch LS. This allows the LS to immediately perform number transformation during call setup without needing to query external databases or intelligent network components, significantly reducing access and processing time.
Data Source
AI summary
The present invention discloses a method for implementing Wide Area Centrex (WAC), wherein the long number and short number corresponding relationship of the WAC users is set and saved. The method includes: routing the call initiated by a user to a soft-switch; receiving by the soft-switch the call information the calling user sends; after determining that the calling user is a WAC user based on the calling number, the soft-switch determining the route to the called user based on the call information and completing the call. The WAC, covering the Public Switched Telephone Network (PSTN)/Public Land Mobile Network (PLMN) user and the Next Generation Network (NGN) user of different physical networks, can be implemented by using the method of the present invention without any software or hardware change to the switches in the existing network.