The number of worldwide 3.5G mobile broadband subscribers will jump from 2.5 million in 2006 to more than 300 million in 2011, analysts predicted today.

However, the predictions of huge growth in the sector by Informa Telecoms & Media are tempered by a warning that market growth this year and next year will be restrained by a paucity of hardware.

"A lack of compelling devices and content led to delayed launches and slow take-up of WCDMA and EV-DO services, and early HSDPA and EV-DO Revision A services are expected to suffer the same problems," said Malik Saadi, principal analyst at Informa Telecoms & Media, and co-author of the Future Mobile Broadband Strategic Report.

Saadi noted that most HSDPA services are launching with only PC cards and notebooks, although a number of early handsets are also arriving.

"However it is striking that as of June no major vendor has unveiled plans for EV-DO Rev. A handsets, although data cards are on the way," he said.

The study predicts that a lack of compelling handsets will slow mass-market take up of 3.5G mobile broadband services in 2006-07, but handsets will start to mature in 2008 leading to a sharp increase in 3.5G handset sales and subscribers in 2008-09.

By 2011 85 per cent of 3.5G devices sold will be handsets, and the remaining 15 per cent will be notebooks and PC cards.

The report defines 3.5G mobile broadband subscribers as subscribers using services based on HSDPA, HSUPA, EV-DO Revision A or EV-DO Revision B.

According to the Informa research, mobile WiMax will compete with HSPA and EV-DO Rev A/B in the mobile broadband market, but will suffer even more than those technologies from the slow arrival of compelling notebooks and handsets.

"Mobile WiMax will play a relatively minor role in the mobile broadband market through 2011, largely because mobile WiMax notebooks and tablets will not arrive in volume until 2008-09, and compelling mobile WiMax handsets won't arrive until 2010," said report co-author Mike Roberts, principal analyst at Informa Telecoms & Media.

"By comparison HSDPA notebooks and handsets are already shipping, which means that the HSDPA device market is one to two years ahead of the mobile WiMax device market."

However Roberts added that these concerns should not obscure the fact that WiMax will gain "significant momentum" in the fixed, nomadic and portable broadband segments in 2006-11, although many WiMax subscribers will be using fixed indoor modems rather than mobile devices.