Roaming Gateway Emulating Network Entities for Interworking
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Solution Overview
Problem
Existing roaming gateways lack versatility in interworking between mobile networks, particularly with the advent of 3G and 4G IP networks that rely on packet-based communication, and fail to efficiently manage subscriber profiles and authentication across different network types.
Innovation Solution
A roaming gateway with an interworking processor that emulates a non-packet mobile network entity, manages subscriber profiles, performs IMSI-based authentication, and acts as a proxy for SIP register requests, enabling seamless roaming and interworking between various network standards, including GSM, UMTS, CDMA, and WLAN networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional roaming gateways are used for interworking between mobile networks, then interworking between SS7-based networks is satisfactory, but versatility with packet-based 3G and 4G networks is insufficient
Solution Approach 1:
The gateway is designed to perform multiple functions by supporting both SS7-based signaling (MAP protocol) and packet-based IP communication (SIP protocol) simultaneously. The interworking processor can emulate different network entities (VLR, MSC) while also acting as a SIP proxy, enabling a single gateway to handle both legacy circuit-switched networks and modern packet-switched networks, thereby achieving universal compatibility across different network architectures.
Solution Approach 2:
The gateway acts as an intermediary between SS7-based networks and IP-based networks. It translates signaling between MAP and SIP protocols, and emulates network entities to bridge the gap between legacy and next-generation networks. This intermediary function allows seamless interworking without requiring changes to either the legacy HLR or the IP network elements.
2Productivity
If existing gateway architecture is used, then simple network interworking is achieved, but subscriber profile management and authentication across different network types is inefficient
Solution Approach 1:
The gateway combines multiple subscriber management functions into a single entity. It integrates the HLR database, VLR emulation, authentication mechanisms (RADIUS, DIAMETER), and SIP proxy functions into one unified system. This merging eliminates the need for separate management systems for different network types, improving efficiency while supporting multiple authentication protocols and network architectures simultaneously.
3Ease of operation
If gateway emulates non-packet network entity, then seamless roaming is enabled, but device complexity increases
Solution Approach 1:
The gateway creates virtual copies of network entities (VLR, MSC) through software emulation in the interworking processor. Instead of requiring physical separate entities for each network function, the gateway uses software-based emulations that can be dynamically configured. This copying approach enables seamless roaming by presenting the same logical interface to mobile devices regardless of the underlying network type, while keeping the physical infrastructure simpler.
Data Source
AI summary
A gateway (1) resides in an IP-based network. It acts as a controlling or home HLR for a mobile device roaming in this network, emulating an MSC or VLR to the home network HLR. Thus, as far as the home network HLR is aware, the subscriber is roaming in a foreign network of equivalent type of technology. Meanwhile, the gateway of the invention manages a subscriber profile and authentication as if the visited network were the home network. In fact, the gateway in combination with the home network HLR acts as an IMS-standard HSS. The gateway (1) enables wireless carriers to use existing legacy network infrastructure to provide a smooth evolution to the next generation network architecture, and it supports voice and data inter-working between existing 2/2.5G networks and next-generation IP based networks. For inter-standard roaming, the gateway 1 extends the existing roaming footprint of an ANSI-41 subscriber roaming in GSM foreign mode. In GSM foreign mode, the ANSI-41 subscriber may roam onto alternative access networks using a sponsor GSM IMSI.