Wireless USB

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 discouraged this practice and instead prefers to call the technology Certified Wireless USB to distinguish it from the competing UWB standard.

Wireless USB was 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 protocols

Wireless USB is used in game controllers, printers, scanners, digital cameras, portable media players, hard disk drives and USB flash drives. It is also suitable for transferring parallel video streams, using USB over ultra-wideband protocols.

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, Staccato Communications, Alereon, Wisair and Samsung.

In May 2005, the Wireless USB Promoter Group announced version 1.0 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 Staccato Communications PHY, all using Microsoft Windows XP drivers developed for Wireless USB.

In October 2006 the U.S. Federal Communications Commission (FCC) approved a Host Wire Adapter (HWA) and Device Wire Adapter (DWA) wireless USB products 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 released a Wireless USB universal docking station in August, 2008 for 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.

On March 16, 2009, the WiMedia Alliance announced transfer agreements for the WiMedia ultra-wideband (UWB) specifications. WiMedia transferred specifications, to the Bluetooth Special Interest Group (SIG), Wireless USB Promoter Group and the USB Implementers Forum. After the technology transfer the WiMedia Alliance ceased operations.[1][2][3] 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.[4][5][6]

On September 29, 2010, version 1.1 of the Wireless USB Specification was announced.[7] 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 is a general term for 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 use UWB for ground penetrating radar, through wall radar and yet another company Pulse~LINK used 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 Implementers Forum 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.

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.[8] 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 products need higher power consumption, and more electronics, which are less suitable for mobile units or devices.

Comparison of digital RF systems

Wireless USB vs. 802.11a/b/g and Bluetooth[9]
Specification Wireless USB Specification Rev. 1.1 Bluetooth 4.0 Wi-Fi (IEEE 802.11n) Wi-Fi (IEEE 802.11ac) Bluetooth 2.1 + EDR
Frequency band 3.1 GHz–10.6 GHz 2.4 GHz 2.4 GHz and/or 5 GHz 5 GHz 2.4 GHz
Bandwidth 53-480 Mbit/s 24 Mbit/s Max. 600 Mbit/s per band[10] Max. 6.93 Gbit/s per band Max. 3 Mbit/s
Distance 3–10 m[11] unknown distance 100 m unknown 1–100 m depending on output
Modulation MB-OFDM MB-OFDM DSSS, DBPSK, DQPSK, CCK, OFDM OFDM GFSK
Standardization September 2010 June 2010 September 2009 December 2013 July 2007

Competitors

Other forms of USB over wireless exist, such as those based on the competing direct sequence ultra-wideband technology by Cable-Free USB.[12] 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.

There is also USB over IP, which may use any IP-based networking solution to transfer USB traffic wirelessly. For example, with proper drivers the host side may use 802.11a/b/g/n/ac Wi-Fi (or wired Ethernet) to communicate with the device side.[13]

See also

References

  1. ↑
  2. ↑ "WiMedia Tech Transfer". USB.org. 2009-03-16. Retrieved 2011-12-02.
  3. ↑ "Incisor Wireless News: What to make of the Bluetooth SIG / WiMedia merger?". Incisor.tv. 2009-03-16. Retrieved 2011-12-02.
  4. ↑ Bluetooth group drops ultrawideband, eyes 60 GHz
  5. ↑ Report: Ultrawideband dies by 2013
  6. ↑ "Incisor Magazine November 2009". Incisor.tv. Retrieved 2011-12-02.
  7. ↑ http://www.usb.org/press/USB-IF_Press_Releases/WirelessUSB_1.1_TechBulletin_Spec_FINAL.pdf
  8. ↑ "Ecosystem". Wireless Gigabit Alliance. Retrieved 2011-12-02.
  9. ↑ Nikkei Electronics 2007/10/8
  10. ↑ "Emerging Technologies in Wireless LANs: Theory, Design, and Deployment". books.google.com. Retrieved 2014-07-13.
  11. ↑ "How fast is Certified Wireless USB? What is its operating range?". Wireless USB FAQ. Everythingusb.com. Retrieved 2014-04-10.
  12. ↑ "Pulse-LINK". Pulse-LINK. Retrieved 2011-12-02.
  13. ↑ "USB/IP Project". Usbip.sourceforge.net. Retrieved 2014-02-23.

External links