CSR gives boost to VoIP mobiles

Chipmaker CSR is hoping to make voice-over-IP (VoIP) a feature common to mass-market mobile phones with the release of a reference design to simplify the addition of a Wi-Fi interface and VoIP software to handsets. Existing handsets can be adapted to take the kit, and it will be built in to new models due later this year, CSR said.

Called UniVox Mobile, the reference design makes use of CSR's UniFi Wi-Fi chip for portable devices combined with a software stack that provides drivers, the session initiation protocol (SIP) for IP voice calls and TCP/IP support.

Some analysts have predicted that VoIP will feature in over 300 million handsets by 2011, but there are still hurdles to overcome to ensure users are comfortable making IP calls, according to CSR.

"Users are not happy with Wi-Fi draining their handset battery, so they often just switch it off. They also want to use their existing phone book for all calls," said Simon Finch, vice-president of CSR's W-Fi Business Unit.

UniVox is so power efficient that handsets will be able to provide up to eight hours of talk time and up to 250 hours standby even with Wi-Fi enabled, CSR said. This is because the UniFi chip was designed from the outset for low-power devices, unlike rival Wi-Fi hardware, and can go into sleep mode between packets.

Software support is equally vital, and CSR said it can provide almost a complete stack for handset makers, especially those using Microsoft's Windows Mobile platform. Vendors only need add a low-level device driver and the station management entity (SME) that governs how a device looks for and connects to Wi-Fi access points.

Finch said that UniVox Mobile also works with CSR's Bluetooth chips to enable both wireless interfaces to operate simultaneously, even though they share much of the same 2.4GHz radio spectrum. This means that users will still be able to use a Bluetooth headset when making VoIP calls over Wi-Fi.

CSR did not disclose how much UniVox Mobile adds to the build cost of a handset, but said it was slightly more than to add Bluetooth. A couple of handsets using the technology are already in the pipeline, Finch said.