Corporate fixed-mobile comms stuck at first base

Phones that work over both Wi-Fi and 3G networks are on the way, but are aimed at consumers

Fixed mobile convergence (FMC) solutions that allow users to make calls over both mobile 3G and static Wi-Fi networks will first emerge as a consumer technology, rather than a business option, as corporate kit continues to be hamstrung by problems of handover between access points.

A number of vendors, including Nokia, Motorola and Sony Ericsson, will introduce new dual mode 3G/Wi-Fi mobile handsets at the 3GSM show in February. Passing calls from Wi-Fi to cellular networks has been proved to work effectively, but network equipment vendors cannot yet guarantee efficient call handover from one Wi-Fi base station to another, with significant latency making continued conversations impossible.

“The IEEE is working on it [the handover problem], but there are still several tens of milliseconds, even 100s of milliseconds, of delay in a call depending on proprietary infrastructure implementations,” said Mikko Salminen, Nokia’s director of FMC marketing.

Mobile operators and service providers are expected to launch commercial FMC services before the end of this year, but they will target residential customers using single rather than multiple Wi-Fi access points, where handover is not an issue.

Business interest in FMC stems from the potential for savings if mobile calls made from the office can be routed as VoIP calls through the private branch exchange (PBX) via the wireless LAN, bypassing expensive cellular tariffs. But return on investment cannot be proven until service providers reveal proposed billing strategies, which now seem likely to involve pre-pay monthly subscriptions for a set number of minutes using dual-mode phones.

For the moment, nobody knows how such costs would work out for businesses, added Salminen.