An increasing number of fixed/mobile convergence, or FMC, deployments are being announced worldwide. In mid-2005, inCode counted two commercial deployments, but more than seven are now underway, with others in the works. Questions have been raised about the relationship between such near-term convergence solutions, which use a combination of cellular and voice-over-IP technologies, and longer-term IP multimedia subsystem architectures. Some have wondered aloud whether operators should simply wait and deploy IMS architecture to support new “blended” services rather than deploy a near-term, pre-IMS, FMC solution and move to IMS later.

The relationship between alternative near-term FMC solutions and IMS turns on several key considerations, including simplicity and cost. Remember that customers buy services and not technology. FMC solutions can offer packaged services while IMS offers the enabling infrastructure. To be sure, IMS is not a precondition for offering FMC services. These services are currently planned or deployed using either unlicensed mobile access (UMA), such as conventional GSM in the cellular area and VoIP over Wi-Fi for in-building coverage, or some version of session initiation protocol (SIP) with conventional CDMA in the cellular area and VoIP/Wi-Fi for in-building coverage. FMC can offer an operator a potentially simpler approach for voice services without significantly altering existing network architecture or changing the way legacy services are supported — both significant cost items.

Several considerations could determine the future path of FMC and IMS developments.

• Pre-IMS FMC services can serve a valuable function by testing customer preference and adoption for converged services. Very little is known about consumer buying patterns and preferences, even when it comes to voice. For example, other than lowering cost by substituting low-cost VoIP for expensive radio minutes, what are the key drivers of converged services? What is the customer buying experience? Are these services integrated, simple, user-friendly and easy to buy? Are existing and new users easily supported? Early deployments of FMC have shown that these aspects have been quite challenging.

• Near-term FMC services can help provide a reality check on many common technology components. These include devices, voice over Wi-FI, back-office systems support and mobility management platforms. By its very nature, FMC requires interaction across multiple billing, provisioning and customer-care systems. Dual-mode device availability and stability across different modes has presented challenges in early trials. By addressing all these important success factors, near-term FMC services can smooth out technology issues on the road to IMS.

• Initial FMC services cannot offer meaningful customer feedback on IMS “blended” services. Almost all the initial focus in FMC deployments has been on voice services. However, this approach does not exploit the blended nature of IMS — the ability to include multiple bearer types within a single session, especially with video. In addition, the value proposition is always under attack by fixed/mobile substitution. As operators roll out FMC for voice, it is critical to plan the evolution to an IMS-enabled multimedia, multi-service session to obtain the true service and economic benefits of convergence.

• Pre-IMS FMC solutions could provide a near-term entry strategy for Tier 2 operators and MVNOs. Current FMC solutions (both UMA- and SIP-based) can enable Tier 2 operators and mobile virtual network operators to offer converged services to their customer base without the expense of building a full-fledged IMS infrastructure.

Yet, momentum appears to be building for IMS, so when purchasing pre-IMS solutions, it is important to do so with a clear evolution path to IMS. Of course, there is no “one size fits all” solution because each provider's strategy and tactics differ. The optimal path to deployment depends greatly upon an operator's commitment to IMS as a unifying infrastructure — typically the case with consolidated carriers — and its ability to commit resources to adoption of the technology.

PK Prasanna is IMS/convergence lead for inCode, a global wireless business and technology consulting firm. For more information, e-mail pprasanna@incodewireless.com.