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  The Certified Wireless USB logo

Wireless USB is a short-range, high-bandwidth wireless radio communication protocol created by the Wireless USB Promoter Group. Wireless USB is sometimes abbreviated as "WUSB", although the USB Implementers Forum discourages this practice and instead prefers to call the technology "Certified Wireless USB" to distinguish it from the competing UWB standard. Wireless USB is based on the (now defunct) WiMedia Alliance's Ultra-WideBand (UWB) common radio platform, which is capable of sending 480 Mbit/s at distances up to 3 metres (9.8 ft) and 110 Mbit/s at up to 10 metres (33 ft). It was designed to operate in the 3.1 to 10.6 GHz frequency range, although local regulatory policies may restrict the legal operating range for any given country.

  Uses

Wireless USB is used in game controllers, printers, scanners, digital cameras, portable media players, hard disk drives and flash drives. Kensington released a Wireless USB universal docking station in August, 2008. It is also suitable for transferring parallel video streams, while utilizing the Wireless USB over Ultra-wideband bandwidth.

  Wireless USB vs. 60 GHz

A few issues differentiate Wireless USB from the use of the 60 GHz band as promoted by the Wireless Gigabit Alliance:

• Line of Sight: at 60 GHz, radio communication is blocked by any intervening object, which implies the need for open line of sight. Wireless USB is based on the Ultra-WideBand (UWB) platform, which operates in the 3.1 to 10.6 GHz frequency range, and thus can pass through intervening bodies.
• Mobility: the 60 GHz technology is appealing to the wireless video market because it is supposed to deliver multi-gigabit-speed wireless communications.^[1] In order to support such heavy demands, the underlying MAC layer should be able to process this huge amount of data. For these requirements, the 60 GHz-based solutions will need higher power consumption, and bigger chips, which are less suitable for mobile units or devices.

  Development

The Wireless USB Promoter Group was formed in February 2004 to define the Wireless USB protocol. The group consists of Agere Systems (now merged with LSI Corporation), Hewlett-Packard, Intel, Microsoft, NEC Corporation, Philips and Samsung.

In May 2005, the Wireless USB Promoter Group announced the completion of the Wireless USB specification.

In June 2006, five companies showed the first multi-vendor interoperability demonstration of Wireless USB. A laptop with an Intel host adapter using an Alereon PHY was used to transfer high definition video from a Philips wireless semiconductor solution with a Realtek PHY, all using Microsoft Windows XP drivers developed for Wireless USB.

In October 2006 the U.S. Federal Communications Commission (FCC) approved the first complete Host Wire Adapter (HWA) and Device Wire Adapter (DWA) wireless USB solution from WiQuest Communications for both outdoor and indoor use. The first retail product was shipped by IOGEAR using Alereon, Intel and NEC silicon in mid-2007. Around the same time, Belkin, Dell, Lenovo and D-Link began shipping products that incorporated WiQuest technology. These products included embedded cards in the notebook PCs or Hub/Adapter solutions for those PCs that do not currently include Wireless USB. In 2008, a new Wireless USB Docking Station from Kensington was made available through Dell. This product was unique as it was the first product on the market to support video and graphics over a USB connection, by using DisplayLink USB graphics technology. Kensington's Docking Station enables wireless connectivity between a notebook PC and an external monitor, speakers, and existing wired USB peripherals. Imation announced Q408 availability of a new external Wireless HDD. Both of these products are based on WiQuest technology.

On March 16, 2009, the WiMedia Alliance announced it is entering into technology transfer agreements for the WiMedia Ultra-wideband (UWB) specifications. WiMedia will transfer all current and future specifications, including work on future high speed and power optimized implementations, to the Bluetooth Special Interest Group (SIG), Wireless USB Promoter Group and the USB Implementers Forum. After the successful completion of the technology transfer, marketing and related administrative items, the WiMedia Alliance will cease operations.^[2][3][4] In October 2009, the Bluetooth Special Interest Group has dropped development of UWB as part of the alternative MAC/PHY, Bluetooth 3.0/High Speed solution. A small, but significant, number of former WiMedia members had not and would not sign up to the necessary agreements for the intellectual property transfer. The Bluetooth group is now turning its attention from UWB to 60 GHz.^[5][6][7]

On September 29, 2010, version 1.1 of the Wireless USB Specification was announced.^[8] It delivers several backwards-compatible improvements: UWB upper band support for frequencies 6 GHz and above, improved power management and consumption, and support for NFC and proximity based association.

  Compatibility options for older hardware

The WUSB architecture allows up to 127 devices to connect directly to a host. Because there are no wires or ports, there is no longer a need for hubs.

However, to facilitate migration from wired to wireless, WUSB introduced a new Device Wire Adapter (DWA) class. Sometimes referred to as a "WUSB hub", a DWA allows existing USB 2.0 devices to be used wirelessly with a WUSB host.

WUSB host capability can be added to existing PCs through the use of a Host Wire Adapter (HWA). The HWA is a USB 2.0 device that attaches externally to a desktop or laptop's USB port or internally to a laptop's MiniCard interface.

WUSB also supports dual-role devices (DRDs), which in addition to being a WUSB device, can function as a host with limited capabilities. For example, a digital camera could act as a device when connected to a computer and as a host when transferring pictures directly to a printer.

  Relation to ultra-wideband (UWB)

A common source of confusion is about the relationship between WUSB, WiMedia, and UWB. The UWB and WUSB technologies are not the same, and the terms WUSB and UWB are not synonymous.

UWB is a general term for a new type of radio communication using pulses of energy which spread emitted Radio Frequency energy over 500 MHz+ of spectrum or exceeding 20% fractional bandwidth within the frequency range of 3.1 GHz to 10.6 GHz as defined by the FCC ruling issued for UWB in Feb. 2002. UWB is not specific to WiMedia or any other company or group and there are in fact a number of groups and companies developing UWB technology totally unrelated to WiMedia. Some companies^[which?] use UWB for ground penetrating radar, through wall radar and yet another company Pulse-LINK uses it as part of a whole home entertainment network using UWB for transmission over both wired and wireless media. WUSB is a protocol promulgated by the USB-IF that uses WiMedia's UWB radio platform. Other protocols that have announced their intention to use WiMedia's UWB radio platform include Bluetooth and the WiMedia Logical Link Control Protocol.

  Comparison of digital RF systems

  Competitors

Other forms of USB over wireless exist, such as those based on the competing direct sequence UWB technology by Cable-Free USB.^[10] The same is also true for other radio frequency based wire replacement systems which can carry USB. The result is that the name Certified Wireless USB was adopted to allow consumers to identify which products would be adherent to the standard and would support the correct protocol and data rates.

  See also

• Bluetooth
• DASH7
• Wibree
• WirelessHD
• Wireless USB specification
• ZigBee
• IEEE 802.15.4
• List of device bandwidths
• TransferJet

  References

  External links

• Wireless USB Promoter Group
• WiMedia Alliance
• Challenges of Migrating to Wireless USB
• 5 Steps to Wireless USB Quality Assurance
• Certified Wireless USB products at USB IF official site
• Latest WiMedia Regulatory Status Chart