CS to PS Call Setup via Gateway Address Resolution
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Solution Overview
Problem
Existing methods for setting up calls between Circuit Switched (CS) and Packet Switched (PS) telecommunication networks require additional network resources and modifications, leading to address format limitations and inefficient use of numbering plans, as well as the need for terminals to maintain multiple address formats.
Innovation Solution
A method where a message comprising both CS and PS network type addresses is stored in a database and retrieved by a network gateway control entity to facilitate call setup, allowing for a two-step process that resolves addresses and connects CS and PS networks without requiring extensive changes to the infrastructure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If E.164 addressing technology is extended to PS network terminals, then call setup between CS and PS networks is enabled, but the CS numbering plan runs out of available numbers and additional network resources are required
Solution Approach 1:
The patent segments the addressing function into two separate components: E.164 address for CS network identification and IP address for PS network identification. Instead of forcing PS terminals to use E.164 addresses, the system maintains both address types separately and uses them in their respective networks, thereby preserving the E.164 numbering plan for CS terminals while enabling IP addressing for PS terminals.
Solution Approach 2:
The patent introduces a gateway entity as an intermediary between CS and PS networks. This gateway performs address translation and routing, converting E.164 addresses to IP addresses and vice versa. The gateway maintains mapping tables that associate E.164 addresses with corresponding IP addresses, enabling seamless inter-network communication without depleting the E.164 numbering plan.
2Adaptability or versatility
If terminals maintain multiple address formats (E.164 and IP), then inter-network calling is possible, but device complexity and maintenance requirements increase
Solution Approach 1:
The patent implements self-service mechanisms where the network automatically manages address format conversion and selection. When a CS terminal initiates a call to a PS terminal, the gateway automatically retrieves the corresponding IP address from its mapping table and handles the translation transparently. Similarly, when a PS terminal initiates a call to a CS terminal, the gateway performs the reverse translation. This eliminates the need for terminal users to manually manage multiple address formats.
Solution Approach 2:
The gateway entity serves multiple functions: it acts as an address translator, a routing director, and a protocol adapter between CS and PS networks. By consolidating these functions in a single multi-functional entity, the system reduces overall complexity compared to requiring each terminal to independently handle multiple address formats and translation protocols.
3Reliability
If network resources are explicitly arranged for CS to PS call setup, then call connectivity is established, but infrastructure complexity and maintenance requirements increase
Solution Approach 1:
The gateway entity is designed as a universal interface that handles multiple types of calls and address translations. It can simultaneously serve CS-to-PS calls, PS-to-CS calls, and potentially other inter-network communication scenarios. This multi-functionality reduces the need for separate dedicated infrastructure for each call type, thereby reducing overall network complexity while maintaining reliable connectivity.
Solution Approach 2:
The gateway acts as an intermediary that abstracts the complexity of inter-network communication from the rest of the network infrastructure. By centralizing address translation and protocol adaptation functions in the gateway, the patent reduces the complexity burden on other network elements such as switches, routers, and terminal equipment, while still ensuring reliable call connectivity between CS and PS networks.
Data Source
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AI summary
A user with a terminal 3 residing in a Circuit Switched (CS) telecommunication network 1 calls a party having a terminal 10 residing at a Packet Switched (PS) telecommunication network 2, the CS 1 and PS 2 networks connected to each other by gateway entity 8. The party to be called at the PS network 2 is addressed by means of a Session Initiation Protocol Universal Resource Identifier (SIP-URI). The call setup is performed in a two step process. In a first step, the terminal 3 sends a the SIP-URI in a message together with the address of this terminal 3 to a network entity 13 which stores said message. In a second step, the terminal 3 calls the network entity 13, wherein the network entity 13 selects the stored SIP-URI and resolves the SIP-URI into an address of the terminal 10 at the PS network and instructs the gateway entity 8 to connect the calling terminal 3 to the terminal 10.