DoCoMo explores single silicon handset

Giant mobile operator NTT DoCoMo is working on a single piece of silicon that will allow phone handsets to roam between 3G and earlier GSM networks around the world.

The company is paying Renesas, a Japanese semiconductor designer, Y7bn (£35m) over three years to help develop the technology, according to a report in this morning's FT.

NTT's 3G phones, based on a version of the W-CDMA standard most countries will use, don't at the moment work with other countries' 2G networks and until now most 'dual-mode' handset designs have relied on two separate chips - which adds cost and complexity.

DoCoMo, Japan's largest operator, is among the few around the world large enough to subsidise phones in this way, the aim ultimately being more customers.