The battle over short-range, high-speed wireless technology Ultra Wideband (UWB) has entered a new phase with the announcement by CSR, a major Bluetooth and Wi-Fi chip maker, that it will back one of the two competing UWB standards.

CSR said it will align its efforts with the Intel-backed WiMedia Alliance, and will begin integrating Bluetooth profiles with WiMedia's flavor of UWB, based on multi-band orthogonal frequency division multiplexing (MB-OFDM) technology. UWB is primarily aimed at extending USB into the wireless realm, but CSR argued that integration with Bluetooth will give WiMedia quick access to a well-established market.

"UWB is the next logical step for Bluetooth development. The decision to work with the WiMedia Alliance is based on end-user experience and that is where WiMedia excels," said CSR chief technology officer James Collier, in a statement. CSR was already a member of the WiMedia alliance, so its announcement was perhaps to be expected, but the company hasn't previously given details of its plans.

Last month the IEEE backed away from the standards-making process around UWB, which promises gigabit speeds over short distances (see also our UWB feature). The decision followed a multiple-year standoff between WiMedia and its rival, Freescale, with its direct sequence-UWB (DS-UWB).

Freescale was first to market with UWB products, and believes its head-start will win the day, while WiMedia is counting on the muscle of its backers -- its 190 members include industry heavyweights such as HP, Intel, Microsoft, Nokia and Sony.

Freescale members such as Belkin are promoting "Cable-Free USB" products, which they say are closer to a simple extension on existing USB technology. Freescale argues WiMedia's "Certified Wireless USB" requires more of a bottom-up redesign from wired USB, adding complexity and development costs.

At the Consumer Electronics Show last month Belkin and Gefen last month launched Cable-Free USB products, the first of what West Technology Research predicts will be nearly 4 million DS-UWB products to ship this year. Belkin has since delayed its Cable-Free USB delivery until the summer.

Certified Wireless USB devices won't be available until the third quarter of this year, according to the Wireless USB implementer's group; last week, testing equipment maker LeCroy delivered the first Certified WUSB testing equipment.