The fourth generation of mobile services - 4G - will be a combination of 3G and WiMax technologies, analyst Forrester has predicted.

According to Bernt Østergaard, vice president and research director at Forrester, 3G will not become the unifying technology umbrella it was originally planned to be, while wireless local area networks (Lans) have crept up on the world.

He predicted that 4G will offer access at Ethernet speeds (such as 10Mbps) and integrated wireless local and wide area networking (Wan) by combining 3G and WiMax in a single handset.

WiMax - or 802.16 - potentially offers wireless broadband services with a range of up to 30 miles, with speeds likely to be around 10Mbps.

Speaking at Forrester's GigaWorld conference in Barcelona, Østergaard said standards around WiMax would begin to solidify by November this year, with devices expected in the first quarter of next year. But he said it would be two to three years before the standard is sufficiently accepted to make 4G a viable service.

Telcos are already investigating the integration of WiMax with their billing systems, he added.

Østergaard said the WiMax standard under development does not allow calls to move from one base station to another without losing the call. Also, as WiMax coverage will not be as wide as 3G, a combination of the two will be needed.

"[WiMax] is not going to replace 3G but it will create the integration between wireless Lan and Wan. Mobile operators have a global coverage that WiMax can't rival," he said, adding that dual WiMax and 3G handsets could be available by 2006/7.

He said companies should develop a wireless policy covering Lans, Wans and metropolitan area networks.