Both Motorola and Nortel have announced efforts to combine 3G phone technology with Wi-Fi, joining an increasing number of companies that see the technologies as complimentary.

NTT DoCoMo will begin selling a new Motorola mobile phone that combines Wi-Fi and 3G from the start of next month. Outwardly, the phone resembles another Motorola 3G phone, the A1000, and like its sibling can connect to 3G networks and older, slower GSM and GPRS networks. However, the M1000 can also connect to wireless LANs based on the Wi-Fi 802.11b.

Like the A1000, the M1000 has a touch-sensitive, 2.9in screen (208x320), a 1.2 megapixel camera and a 300,000 pixel video camera. The M1000's battery contains enough energy for 80 minutes of videoconferencing over a 3G network, 280 minutes just talking over a GSM connection, or 200 hours on standby, according to Motorola.

In addition to its Wi-Fi connection, the Symbian phone can link to computers via Bluetooth or USB. It contains the Opera 7.5 browser; an e-mail client; the movianVPN 4.0 IPsec VPN client; and document viewers for e-mail attachments in formats including Acrobat, Word, Excel, PowerPoint and Zip. It can also run Java applets compatible with the MIDP 2.0 spec.

The phone will initially only be sold in Japan and there are no plans yet to launch the device elsewhere, according to Motorola spokeswoman Naomi Kondo.

Meanwhile, Nortel and BB Mobile have demonstrated a system - again in Japan - that allows mobile-phone users to roam between 3G and Wi-Fi networks.

The two said they have conducted test calls while roaming between a WCDMA network and a wireless LAN. Based on technology developed by Nortel, the system allows users to switch between the two networks without interrupting voice calls or data sessions, such as downloading e-mail or surfing the Internet.

The announcement follows a statement released earlier this month that Nortel and BB Mobile had conducted tests of a mobile network based on HSDPA, a high-speed data add-on for WCDMA.