Future Ready

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Voice&Data Bureau
New Update

Before constructing a future-oriented core network, operators need to understand the current status and deficiencies of core networks. While access networks get more and more flattened and simplified, core networks are becoming increasingly complex, as bearer and control as well as control and service capabilities are separated from each other. The increasing number of same-type NE nodes (due to limited capacity), and numerous internal and external interfaces (and protocols) have added to the complexity, leading to a cumbersome network operation & maintenance with a low network reliability and efficiency. This is also leading to mounting operational expenses in terms of maintenance resources, room space, and power consumption.

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Isolated networks and environments cannot deliver integrated services and experience. Statistics show that 29 of industry's top 30 operators offer both fixed and mobile services and are moving towards providing full range of services. Still, most telco networks are built on a structure that separates fixed and mobile capabilities. Each system is maintained separately, resulting in heavy workloads and low efficiency. As service control points are distributed in the two systems, it is difficult to deliver a user experience that integrates fixed and mobile services impacting end user loyalty.

Operators are today struggling with increasing competition from Internet and IT applications. Analysts predict that by 2013, voice service will remain the cash cow for operators, contributing over 70% to total revenues. However, pressure is mounting from a wide variety of IT and Internet applications like IM, VoIP, SNS etc, that are more versified and grabbing market share from voice services.

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Future-oriented ALL-IP Core Network

Clearly, networks need to be convergent and unified, simplified and efficient, evolving and compatible, open and interconnected. The traditional TDM or softswitches shall hence evolve towards IMS-centric protocol systems and solutions to provide answer to these challenges.

Convergent & Unified

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The key challenge for an operator is to keep the O&M costs low while offering fixed/mobile voice and broadband services, thus making it imperative to build a convergent network free of segmentation or isolation.

A convergent and unified core network should have the following key features:

Integration of Session and Access Control: The converged core must be able to control at least the following five mainstream access modes: GSM, UMTS/HSPA, LTE/WiMAX, PSTN, and xDSL/FTTx, while delivering a unified experience. The integrated IMS core network makes sure of the authentication, routing, and triggering of services for all these access methods to offer a unified access experience.

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Common TAS for Service Consistency in Multi-access Modes: Access-independent unified control nodes require a common telephony application server (TAS) to provide unified and convergent service capabilities. In addition to the basic voice and video service combinations necessary for FBB and MBB, the common TAS must incorporate a number of traditional fixed and mobile network services. To meet requirements of enterprise customers, the common TAS must provide advanced voice service features like IP Centrex.

Convergent User Data Center for Network Convergence: Under legacy network architecture, subscription data is stored in different places. A convergent user data center is a “must have” when a network evolves from CS/PS towards IMS/SAE, as it provides a bridge for future network evolution and smooth user migration.

Simplified & Efficient

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With falling ARPU, operators need to improve networking efficiency and exploit the potential of their networks to reduce opex and capex through the following two approaches:

Unified and High-performance Software/Hardware Platform: The introduction of high-performance blade servers and virtualization technology makes possible integration of numerous NEs into one hardware platform as demonstrated by ATCA (Advanced Telecommunication Computing Architecture). The unified platform helps reduce maintenance costs by sharing spare parts.

Integrated Site Management, Optimal Collaboration of Protocols: Based on a unified software/hardware platform, different NEs in a site can be housed in the same frame and cabinet by sharing common components, such as billing server and IP inter-working units.

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Evolving & Compatible

Mass LTE deployment is predicted to happen in 2012 or 2013. New-generation Core Networks are required to support VoLTE and backward compatibility with 2G/3G networks.

Ability to Integrate All Existing Services: The evolution towards an IMS-based new-generation core network is unlikely to progress independently from existing networks as user habits and experience with legacy networks will not change radically.

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Minimal Impact on Existing Networks, Easy Deployment: Unlike access and transmission networks, the core network provides a wide variety of interfaces and protocols. A new network structure requires the transformation of related network layers.

Support for New Broadband Applications such as MMTel and RCS: The new-generation core network should support new broadband applications like multimedia telephony (MMTel) and the rich communication suite (RCS). In addition to enhancing user experience and loyalty, these services empower operators to compete with Internet based applications, such as MSN, QQ, Skype, and Google Voice.

Dynamic Resource Allocation, Software-based Smooth Evolution: Network evolution usually goes hand in hand with user migration. Amid the transition to broadband access technologies such as LTE/FTTx, voice will be moving from VoCS to VoPS. Similar to user migration from 2G to 3G, the core network must support a combination of 2G, 3G, and 4G access capabilities as these access technologies will coexist over a long time in evolution towards LTE.

Open & Interconnected

Operators will be able to create a market space if they open and charge fees on more valuable resources like subscription data, communications capabilities, user status etc.

Open Architecture: Core network NEs communicate with each other through standard protocols, and devices from different vendors can interoperate with one another, allowing operators to choose products that best suit their needs. The IMS Centralized Service (ICS) architecture, which is defined in 3GPP R8, is an option that provides the possibility for a new generation core network to support 2G/3G/4G convergence, FMC, and convergence of narrowband and broadband.

Open Capabilities: To create a winning business model, new generation core networks must have an open service gateway (OSG), allowing operators to open core network capabilities.

Open Access: End users need to have access to services on the network anytime, anywhere and the communication policies need to be adapted to their needs and preferences. A web based personal service portal is integral to the core network. Users can access the portal through any terminal to make calls (click to dial) or set communications policies, such as binding terminals and setting a routing policy for the called party.

Smooth Evolution of Core Networks

The overall core evolution can be done in a three step process:

  • All-IP and FMC
  • All-service broadband and multimedia
  • IT and CT convergence

All-IP and FMC

In the initial stage, operators that prioritize mature and widely available solutions can opt for a mature soft-switch solution. Those that hope for future-proof evolution can choose a 2G/3G/4G solution based on the 3GPP R8 ICS architecture.

All-service Broadband and Multimedia

Given an IMS based network structure, users will be gradually migrated from VoCS to VoPS as broadband technologies such as LTE/FTTH become available.

IT and CT Convergence

Broadband & IP capabilities will ultimately push networks towards ICT convergence. Telecom networks should incorporate innovative Internet applications to enhance user experience, while the Internet requires communications capabilities and user data (with real names) from telecoms to make the applications more relevant and widely available.

With the increasing maturity of computing technology, cloud computing will be integrated into telecom networks to improve their efficiency and flexibility in using hardware resources.

Sethumadhavan Srinivasan
The author is deputy director,
marketing & strategy, Huawei India
vadmail@cybermedia.co.in