LTE: Breathing New Life Into IMS?

By Simo Isomäki, Dynamic OSS Solutions, Comptel Corporation

Do you remember the hype around IMS – IP Multimedia Subsystem? A few years ago, a frenzy erupted around the network infrastructure, until communications service providers (CSPs) faced a stark reality check when forced to justify the costs of the technology deployment. When first introduced, IMS was an “all or nothing" proposition, and operators became uncertain whether it would drive enough revenue. In the end, only a few actually rolled IMS out.

But IMS is now back on the table. According to a recent ABI Research study, there will be more than a 100 percent increase in IMS sales over the next five years, from an approximate $8.4 billion IMS spend during 2009, to an estimated $17.3 billion spend 2014. The technology that was once thought dead has been revived.

IMS: A Long-Term Evolution Itself

There’s no doubt, Long Term Evolution (LTE) has played a major role in IMS’ comeback. But the rapid adoption of LTE and the resurgence of IMS are not as intrinsically linked as they may at first appear. LTE certainly benefits from key elements of the IMS architecture, but there are a number of other factors that are also driving adoption of IMS, albeit more gradually and incrementally.

Trends, such as the massive increase in mobile broadband and the development of packet core networks, are slowly moving the industry toward an all-IP environment in which IMS components naturally fit. For example, look at the amount of work completed around the Diameter protocol – a guideline embraced by the 3rd Generation Partnership Project (3GPP) and the European Telecommunications Standards Institute (ETSI) standard bodies. This serves as the foundation for Authentication, Authorization and Accounting (AAA) functionalities.

Recently, the NGN/IMS Forum also named Diameter the de facto protocol for policy management. Both Diameter and IMS are gaining momentum because CSPs are seeking operations support systems (OSS) solutions to engage in a customer-centric approach to policy control. By addressing the main concepts involved with Diameter – interoperability and integration – and how it fits with IMS, operators will be able to bridge the gap between legacy and newer technologies, monetize next-generation network (NGN) services, and improve the customer experience. This, in turn, will help drive the adoption of next-generation, IMS-based networks.

Another factor driving the longer term evolution toward all-IMS architectures is the growing interest in using customers’ data for active decision-making in business and OSS. There is an increased need for customer-centric fulfillment and charging, mirrored by the evolving role of customer information repositories, such as Generic User Profile (GUP), Subscriber Profile Repository (SPR), Home Subscriber Server (HSS) and Home Location Register (HLR) and others, as well as the significantly increased awareness and adoption of 3GPP-aligned strategies. While data management is still a major challenge and syncing all of these repositories is still a major headache, there is no doubt that customer data and intelligence are moving toward the network – as IMS requires it.

Evolution, Not Revolution

There is clear evidence the foundations for IMS are already being laid pre-LTE. But when operators do eventually deploy LTE, they are unlikely to switch to all-IMS architectures right away because of established 2.5G and 3G networks. Despite the growth in data, voice still contributes the lion share of revenue and does not require an all-IP environment for service delivery. The Circuit Switched (CS) core is still there, why not use it? Just like Public Switched Telephone Network (PSTN), the CS core will be more or less a place where no new investments are made, and if they are made, it’s because the latest network solutions offer substantially lower costs, if nothing else.

Furthermore, while the IP core is struggling to cope with the load of data traffic caused by smartphones, netbooks and other advanced devices, operators are adopting the wrong strategy if they put their money-making voice onto an overloaded (or soon-to-be overloaded) IP network. There may be a time when it will make economic sense to move to an all-IP network, but operators will also be keeping a CS network. And that also means that IMS will have to sit alongside more traditional and indeed legacy systems.

It is also worth highlighting China. While the rest of the world is contemplating a move to IMS, China Mobile, and more recently China Telecom, are going where virtually no other CSP has gone before – a large scale, nationwide IMS infrastructure. Aside from the examples these operators are setting, this will mean some OSS vendors who supply the network-side kits to these investments will be in a fairly strong position in the future –gaining invaluable experience that will serve to reassure other CSPs about IMS. This move will impact the telco sector much more than can even be imagined today.

Slow and Steady Wins the Race?

Simo Isomäki is the vice president of Comptel Dynamic OSS solutions at Comptel Corporation.  Simo has more than ten years of experience in the telecommunications and BSS/OSS industry.  He has a broad range of expertise in telecom business processes, OSS/BSS systems, standards (e.g. TM Forum (eTOM, SID, TAM), 3GPP, IETF, ITU-T, GSMA) and telecom software architectures.  Prior to joining Comptel, Simo held a number of positions at Nokia Networks (now NSN).