Telephony: Clearing Some Fog and Noise

Just when I thought I was clear on fixed-mobile convergence (FMC), I got two new press releases that started another train of thought. They made me think that from the consumer's point of view, the choices to be made as service providers offer the quad play are going to be confusing. Depending upon where you need the seamless tie between landline and cell phone, and who your favorite carrier is, FMC means totally different types of services.

Generically speaking, the concept behind all FMC offerings is simple. You make your phone calls using a dual-mode cell phone, and sometimes you are talking over a cellular carrier's network, and other times you are talking over a landline service provider's network. As a telephone user, you don't notice when the transition occurs.

If you probe a bit deeper, however, you find out that it may pay to watch the icons on the phone screen. Depending upon which carrier you're using, the rates will change. Also, the way they change will be different for voice than for a data application.

Location, location, location

But let's forget about the pricing details for a minute, and concentrate on where the convergence is occurring. Most talk in cable has been about a residential or small business application, where the landline phone service is a wireless 802.11 (aka Wi-Fi) extension of PacketCable-based voice over Internet protocol (VoIP) through a multimedia terminal adapter (MTA) and cable modem. Knitting the seamless fabric of convergence is the job of a redesigned call management server (CMS) and elements of IP multimedia subsystem (IMS), in particular, the home subscriber server (HSS). The technology vision is that when you leave the 802.11 coverage area, the CMS sets up the signaling needed for your dual-mode handset to home onto the nearest cellular tower. The reverse happens if you originate the call via the cellular handset mode. At some point, WiMax may replace 802.11.

Vendors in our industry are pretty close to having production hardware to do the job. Arris Senior Director Jeff Brooks tells me that the Arris TTPM552 embedded MTA (EMTA) is targeted for the first half of this year, with two wireline ports, an Ethernet connection, and an 802.11 interface. The path to WiMAX is also marked. "Our early trials indicate that the 802.11 port could be used in a WiMAX mesh network," said Brooks, "but the question is how soon the WiMAX technology will be available for commercial use." Full Story »