Introduction
The traditional telecommunications industry is separated into two worlds: the world of mobile and the world of fixed line communication. Each has different business models, various tailored networks for specific purposes, diverged organizations and services. This separation was reasonable in times of steady and strong vertical market growth for each respective domain, however recent declining voice ARPUs (Average Revenues Per User) and new emerging services (like presence, push-to-services (to-talk, to-view, to-video), rich call (Video ,data), group chat, colored ring tones, instant messaging, unified messaging, multiparty gaming, personal info services (calendars, alerts, ect.),video streaming, video, audio and web conferencing are exerting tremendous pressure on both mobile and fixed operators as they compete for the same subscriber and service revenues.
Fixed-mobile-convergence (FMC) – the integration of wireline, wireless and cellular technologies with services to create a single telecommunications network enables telecom service providers to reach all of their potential customers with different types of services, whether being wireless, wireline, cable, or cellular clients. This trend is strongly pushed (or advocated) by the ever-increasing availability of new wireless network technologies, particularly the IMS (IP Multimedia Core Network Subsystem) framework.
IMS Architecture and Standards
In 1998, a group known as the Third Generation Partnership Project (3GPP) was founded by a global consortium of standards bodies to define a next-generation mobile architecture that continued to build on the success of GSM. The architects of the 3GPP recognized that the traditional approach of deploying vertically integrated enhanced services was inefficient and set out to develop a horizontally layered architecture for enhanced service delivery. This new architecture was designed to minimize costs for the service provider, whilst supporting the universal delivery of enhanced services, regardless of the access technology used by subscribers to reach those services. The 3GPP subsystem responsible for enhanced services is known as the IMS or IP Multimedia Subsystem.
The key components of the IMS are shown in figure 1. The Serving Call State Control Function (S-CSCF) provides the centralized “intellect” of the IMS through interactions with the various service platforms. The S-CSCF maintains session state, while interacting with the gateways, service platform elements, and charging functions for the overall service delivery. The Home Subscriber Server (HSS) continues its role as the main data storage for all subscriber and service-related data. Interworking with the PSTN and Internet is provided by various gateway elements defined by the 3GPP – namely the Media Gateway (MGW) for the PSTN or younger-generation wireless networks, and the Gateway GPRS Support Node (GGSN) for connectivity with the Internet. The IMS uses a common IP core with SIP-controlled end points, whereby SIP is used to setup, maintain and terminate multimedia sessions. Key elements of the IMS architecture relate to enhanced service delivery and include, Application Server (AS), the Multimedia Resource Function Controller (MRFC) and the Multimedia Resource Function Processor (MRFP).
- The MRF is used for multiparty call control- it is composed of MRFC and MRFP
- Those entities are responsible for interworking between IMS and CS domain/PSTN
AudioCodes offerings
The solution proposed by AudioCodes for Fixed Mobile Convergence is based on a common IP Multi-Media Subsystem (IMS) approach. AudioCodes provides the fixed-mobile-converged MediantTM 2000/3000/5000/8000 platforms such as the MGW, SG entities and IPmedia 2000/3000/5000/8000 as the MRFP entity in the IMS infrastructure. Figure 2 below shows IMS centric architecture for Fixed-Mobile Converged network:
AudioCodes Converged Mediant™ carrier grade MGW key features are:
- Cost-effective and scalable platforms
- Starts as a single T1, E1 or J1
- Scales up to 18,000 channels per shelf and 54,000 channels per frame, with STM-1/OC-3 PSTN interfaces
- Supports wireline, carrier or enterprise deployments
- Supports cable deployments (PacketCable compliant)
- Supports CDMA, GSM and UMTS (R4 & IMS-based) deployments with VoIP and/or cellular vocoders on a single platform
- Suitable for fixed-mobile-converged deployments
- Provides broad global PSTN CAS, ISDN PRI and SS7 signaling and SIGTRAN (SS7: M2UA/M3UA,PRI: IUA) as a SG
- Integrates 3G and 2G packet-enabled media gateway functionality into end-to-end system solutions
- Meets the demands of both ATM and IP from a single media gateway platform
- Field-proven, high quality voice processing
- Easy straight forward management with AudioCodes’ Element Management System (EMS)
The IPmedia™ platforms (as MRFP entity in the IMS framework) meet the needs for enhanced media services in VoIP/VoATM, wireline, cable and wireless markets with a right-sized and cost-effective media server ,enabling enhanced services such as network announcements, conferencing, Interactive Voice Response (IVR), pre-paid, transcoding and messaging.