Wireless USB
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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 differentiate it from competitors (see below, "Competitors"). Wireless USB is based on the WiMedia Alliance's Ultra-WideBand (UWB) common radio platform, which is capable of sending 480 Mbit/s at distances up to 3 meters and 110 Mbit/s at up to 10 meters. 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.
[edit] Uses
Wireless USB is used in game controllers, printers, scanners, digital cameras, MP3 players, hard disks and flash drives. It is also suitable for transferring parallel video streams.
[edit] Development
The Wireless USB Promoter Group was formed in February 2004 to define the Wireless USB specification. 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 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. Since then, in mid-2007 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.
[edit] Host wire adapters, device wire adapters, and dual-role devices
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 the 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.
[edit] 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. 2001. 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 Penetration 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.
[edit] WUSB vs. Bluetooth
Wireless USB and Bluetooth are two different protocols trying to accomplish two entirely different goals. Wireless USB is a high bandwidth wireless protocol with a smaller range than WiFi (and larger bandwidth, and a much reduced power profile), but with higher transfer rates than Bluetooth (though both share a similar range and may be able to use the same PHY/Transceiver hardware much like combo Bluetooth+WiFi devices). Theoretically, a single 2.4 GHz radio device could be constructed that works with all three protocols seamlessly, with any necessary decoding/encoding performed within software.
Bluetooth specification 3.0 is currently ongoing and has the goal to also use UWB. In parallel also WiFi shall be seamlessly integrated. There will be negligible differences in throughput when the 3.0 specification is finished. Bluetooth has advantages compared to Wireless USB when it comes to connection establishment. Wireless USB does not have service level security and service discovery. Bluetooth has long experience with connection establishment so a connection can be established from any device. In Wireless USB connection establishment can only be done from the device side.
[edit] Comparison with other digital RF communication systems
| Specification | Wireless USB Specification Rev. 1.0 |
Bluetooth 3.0(proposed) | IEEE802.11a/b/g | Bluetooth 2.0 + EDR |
|---|---|---|---|---|
| Frequency band | 3.1 GHz–10.6 GHz | UWB (not decided) | 2.4 GHz/5 GHz | 2.4 GHz |
| Transfer speed (distance) |
480 Mbit/s (3 m), 110 Mbit/s (10 m) |
53 - 480 Mbit/s (unknown distance) |
Max. 54 Mbit/s (100 m) |
Max. 3 Mbit/s (1 m–100 m, depending on output) |
| Modulation | MB-OFDM | MB-OFDM | DSSS, DBPSK, DQPSK, CCK, OFDM |
GFSK |
[edit] Comparison of 4 regions RF bands
[edit] Competitors: Certified Wireless USB vs WirelessUSB
[edit] WirelessUSB
"WirelessUSB" by Cypress Semiconductor is not related to "Certified Wireless USB".
Cypress's "WirelessUSB" is a protocol that uses the 2.4 GHz band with a range from 10 meters (at max 1 Mbit/s) to 50 meters (at max 62.5 kbit/s) and is designed for Human Interface Devices (HIDs), with current offerings from companies such as Belkin, Logitech, Gyration Inc., and Virtual Ink.
[edit] UWB
Other forms of USB over wireless exist, such as those based on the competing direct sequence UWB technology by Freescale (Cable-Free USB). 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.
[edit] References
[edit] See also
- Bluetooth – IEEE 802.15.1
- Wibree
- WirelessHD
- Wireless USB specification – technical overview
- ZigBee – IEEE 802.15.4
- List of device bandwidths
