More and more people are making voice calls over wireless data networks, and as technology develops further, VoWLAN is going to experience exponential growth. These are the conclusions of two research groups -- Frost & Sullivan and Infonetics Research. Of special importance is the increasing number and sophistication of dual-mode handsets, which allow customers to switch between cellular and WiFi networks. In 2004, worldwide revenue from dual-mode handsets reached $6.7 million and totaled $54.7 million from all WiFi VoIP handsets, according to Infonetics. F&S said that dual-mode handsets would help mobile providers increase revenue per user and reduce customer churn, because allowing customers to switch between WiFi and mobile phone networks effectively increases coverage.

The debates over which standards and technologies to use for VoWLAN need to be settled first. Fourteen major phone vendors and telecom operators push unlicensed mobile access (UMA), but this is problematic as a long-term solution because it does not fully support SIP, which is used for VoIP, push-to-talk, and messaging. It is also not aligned with Internet protocol for multimedia subsystems (IMS) for creating converged networks. QoS is also an issue, but many see 802.11e effectively addressing it since it would prioritize voice over data communications and would also help in interoperability. 80211e will be ratified later this year.

F&S predicts that revenues for the European VoWLAN market will increase from €6.6 million in 2004 to €1.9 billion in 2010, an annual growth of nearly 160 percent.

For more on this latest vote of confidence in VoWLAN:
- see silicon.com's report