The architecture known as the IP multimedia subsystem, or IMS, is at a critical stage in its development. It's one of those emerging technology areas that is not truly or fully understood by the vast majority of the industry — or at least it is understood differently by various factions of the market. IMS, like other new technologies, is in its earliest stages being trumpeted most by the developers pushing it rather than the carriers poised to deploy it. That's nothing new and certainly not surprising, as long as its life cycle continues apace.

The reason the overall telecom industry — and the wireless arm in particular — can afford to be more confident about IMS than, say, something as elusive and unpredictable as mobile applications, is that IMS is based on IP. IP technology has become nearly synonymous with the next generation of telecom networking, from the cores of networks all the way out to their edges and the applications carried over them. IP literally has redefined how networks are designed and how services are created. So for IMS — the virtual glue that promises to bind wireline and wireless architectures together and deliver on the long-promised phenomenon of network convergence — to be based on IP gives it almost immediate credibility. That's why IMS emerged and established eminency practically overnight: It is the natural next step in IP networking, a subject on which (for once) most of the telecom industry agrees.

That's also why we decided to devote the majority of this issue of Wireless Review to the subject of this architecture. IMS as a concept was spawned in the wireless sector, as part of specifications created by the 3G Partnership Project, so it seems only natural that a definitive report on the development and application of IMS should be in a publication devoted to covering wireless technology innovation.

To that end, our editorial staff has devoted many pages of this issue to an exploration of the implications of IMS: On page 30, Dan O'Shea takes a sweeping look at wireless/wireline convergence and how IMS will facilitate it. On page 38, Kevin Fitchard explores the role of voice over IP in wireless networks. And on page 42, Jason Ankeny analyzes the location-based services sector and how IMS could help it expand.

Our mission from the outset of taking on this publication was to offer wireless service providers an advanced and comprehensive look at developing technologies and to analyze how they promise to affect the future of wireless network operations and strategy. At this point in the evolution of the wireless industry — or, rather, the converged network industry as a whole — it's clear that much of that future depends on the implications of IMS.