Wi-Fi/mobile convergence approaches

The 'holy grail' of wireless/IP convergence, whereby a dual-mode phone call seamlessly hands off from a Wi-Fi network to a mobile network, is still a rare phenomenon but is becoming more common, according to industry watchers.

ABI Research noted that users are already taking small steps towards this convergence in the form of a new class of specialised Wi-Fi access points designed to support voice-over-IP.

Connected to a VoIP network and phone service, these access points provide VoIP's cheaper services to cellular phone users within range of their Wi-Fi transmitters. They may also offer indoor coverage which is better than cellular.

If users leave the Wi-Fi coverage zone, and if their mobile operator supports such services, these devices will also hand off calls from Wi-Fi to cellular. Motorola's recently announced RSG system, expected late this year, exemplifies the trend.

Philip Solis, senior analyst for wireless connectivity research at ABI, predicted that there will be considerable benefits if such projects are successful.

"It will validate the idea and the importance of voice-over-Wi-Fi," he said. "Even a system providing a limited service, without operator-supported handoffs, offers rewards in the form of cheaper calls and better indoor coverage."

Solis added that if these VoIP/Wi-Fi access products enjoy considerable market success, this would also support analyst forecasts of a boom in dual-mode cellular/voice-over-Wi-Fi devices.

However, the analyst warned that much work remains to be done by the industry to arrange how services are charged and minutes billed before seamless handoffs become an attractive proposition to most carriers.

"ABI Research would urge mobile operators that lag behind in offering con verged services to pick up the pace, or risk losing revenue to their nimbler competitors or to lower-cost workarounds," said Solis.