Wireless USBWireless 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.

[edit]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.

[edit]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.

[edit]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.

[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.

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.

[edit]Comparison of digital RF systems

Wireless USB vs. 802.11a/b/g & Bluetooth[9]

Specification

Wireless

USB

Specificatio

n Rev. 1.1

Bluetooth

4.

0(proposed)

Wi-Fi (IEEE 802.11n)

Wi-Fi 

(IEEE

802.11a

c)

Bluetoot

h 2.1

+ EDR

Frequency

band

3.1 GHz–

10.6 GHz2.4 GHz 2.4 GHz and/or 5 GHz 5 GHz 2.4 GHz

Bandwidth53-480

Mbit/s1 Mbit/s Max. 450 Mbit/s per band

Max.

6.93

Gbit/s per

band

Max. 3

Mbit/s

Distance 3–10 munknown

distance100 m unknown

1–100 m

dependin

g on

output

Modulation MB-OFDM MB-OFDM DSSS, DBPSK, DQPSK, CC OFDM GFSK

K,OFDM

Standardizatio

n

September

2010June 2010 September 2009

pre-

standardJuly 2007

[edit]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.

References

1. ̂  "Ecosystem". Wireless Gigabit Alliance. Retrieved 2011-12-02.

2. ̂  [1][dead link]

3. ̂  "WiMedia Tech Transfer". USB.org. 2009-03-16. Retrieved 2011-12-02.

4. ̂  "Incisor Wireless News: What to make of the Bluetooth SIG / WiMedia merger?". Incisor.tv. 2009-03-16.

Retrieved 2011-12-02.

5. ̂  Bluetooth group drops ultrawideband, eyes 60 GHz

6. ̂  Report: Ultrawideband dies by 2013

7. ̂  "Incisor Magazine November 2009". Incisor.tv. Retrieved 2011-12-02.

8. ̂  http://www.usb.org/press/USB-IF_Press_Releases/WirelessUSB_1.1_TechBulletin_Spec_FINAL.pdf

9. ̂  Nikkei Electronics 2007/10/8

10. ̂  "Pulse-LINK". Pulse-LINK. Retrieved 2011-12-02.

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

REFERENCES

Alereon: http://www.alereon.com/

Artaflex: http://www.artaflexmodules.com/products.html?cat_id=1

Aurel: http://www.aurelwireless.com/

Bluetooth: http://www.bluetooth.com/

Cypress: http://www.cypress.com/products/

Fontana 2004: http://www.multispectral.com/pdf/MTT52No9.pdf

Griffith 2006: http://www.ultrawidebandplanet.com/resources/article.php/3578521

Hazen 2006: http://rfdesign.com/next_generation_wireless/ieee-task-group/

Intel: http://www.intel.com/technology/comms/uwb/

Lunttila et. al 2004: http://www.prosessori.fi/es04/ARKISTO/PDF/UWB_TEKNIIKKA.PDF

Unigen: http://www.unigen.com/

USB.org: http://www.usb.org/

Wimedia: http://www.wimedia.org

ADVANTAGES AND DISADVANTAGESAdvantages:

Flexible if there is ad-hoc situation when additional workstation was required. 

Implementation cost is cheaper than wired network.

Ideal for the non-reachable places such as across river or mountain or rural area.

Ideal for temporary network setups. 

Disadvantages: 

Lower speed compared to wired network. (of course!)

Less secure because hacker's laptop can act as Access Point. If you connected to their laptop,

they'll read all your information (username, password.. bla..bla..bla..).

More complex to configure than wired network.

Affected by surrounding. E.g: walls (blocking), microwave oven (interference), far distance

(attenuation)

CERTIFIED WIRELESS USB

Certified Wireless USB is the natural evolution and extension of the ubiquitous Universal Serial

Bus (USB) protocol, first introduced in 1994. Since its introduction, USB has become the de

facto standard in the personal computing industry, with billions of devices in use around

the world. Wireless USB promises to expand on the legendary ease of use of traditional

wired USB by extending the "plug-and-play" paradigm to an environment where the

cables between the PC and devices no longer exist.

At the heart of Certified Wireless USB is a radio technology new to the consumer space:

Ultra-wideband. This high-bandwidth, low-power method of wireless data transmission

enables the secure, high-speed connection required for the USB-like user experience.

This radio platform, developed by the WiMedia Alliance, was chosen in 2004 to serve as

the foundation for wireless USB. The official specification, released as version 1.0 in

May 2005 by the Wireless USB Promoter Group, will be revised to version 1.1

sometime in 2008 and add updates for better power efficiency and support for

frequencies above 6 GHz.

Certified Wireless USB was designed from the ground up to address the specific

challenges of wireless communications and personal networking. It is based on an

Ultra-wideband (UWB) radio system called orthogonal frequency division multiplexing

(OFDM) which was created by the WiMedia Alliance expressly for wireless USB. The

Wireless Promoter Group, consisting of seven companies - Intel Corporation, HP, LSI

Logic, Microsoft Corporation, NEC Corporation, NXP Semiconductors, and Samsung

Electronics - defined the core specification with the support of more than 100

contributing members. This specification, called Wireless USB Specification version 1.0

(soon to be 1.1), is managed by the USB Implementers Forum (USB-IF). Certified

Wireless USB includes features necessary for the long-term viability of the solution,

such as radio power management, additional security features, and, the potential for the

datarate to improve as Certified Wireless USB support is adopted natively by new

hardware and operating system updates. 

1. How fast is Certified Wireless USB? What is its operating range?Real-world performance is expected to vary greatly depending on the distance required.

Wireless USB is designed for optimal performance when the devices are less than 10

meters (33 ft) away from the computer. Although speeds of up to 480 Mbps are

advertised, this is a theoretical maximum. It is reasonable to expect performance

upwards of 50-100 Mbps at short range, with performance decreasing as distance

increases. As more computing systems integrate native support for Wireless USB rather

than using dongles or adapters, it is reasonable to expect performance approaching 200

Mbps and beyond. 

2. Why might I want Certified Wireless USB?Certified Wireless USB builds upon the consumer awareness of USB and its legendary

ease of use. Similar to the impact on networking and the freedom that Wi-Fi brought to

mobile internet access in the last decade, wireless USB promises a user experience

with fewer cables. This means consumer electronics without the typical rat's nest of

wires, easier installation and set-up for devices in the digital home, and revolutionary

new products such as wireless monitors and displays.

Apart from removing the wires from computer peripherals to make them more

convenient to use, wireless USB opens up some rather interesting product

opportunities. Imagine eliminating the thick cables between your display and your

computer. Or streaming video to multiple displays within a room - including your 60-inch

flat panel - without a video splitter and without video cables. Digital cameras would be

able to store the captured images not just on large flash cards in the camera, but on

much larger storage devices stored in a briefcase or in a jacket pocket. That same

digital camera could then stream pictures and video to any wireless USB enabled

display in the room. Because the maximum throughput of wireless USB promises to be

significantly higher than the fastest Wi-Fi connections, richer and more interactive user

experiences will be possible. 

3. How does Wireless USB work?Certified Wireless USB builds on top of the fundamental operational model of traditional

wired USB. That is, wireless USB connects devices such as printers, keyboards, and

storage media to the computer in a "plug-and-play" fashion, but without cables. In order

to accomplish this, both new hardware adapters and new software drivers are required.

At the heart of a wireless USB system is the radio and antenna system. Certified

Wireless USB employs a wireless technology called Ultra-wideband (UWB), which

operates in the frequency range of 3.1 to 10.6 GHz. (For reference, 802.11 Wi-Fi

networks are commonly operating at 2.4 GHz, the same frequency as some cordless

phones, microwave ovens, and Bluetooth devices). One of the key advantages to a

UWB system is the low power consumption (great for portable devices) and wide

frequency spectrum of operation.

UWB is actually not a new technology - it was invented in the 1960s primarily for military

use in secure communications and ground-penetrating radars. Mainly a technology

developed under classified US government programs, UWB now enjoys much more

research and development attention without classification restrictions.

The ultra-wideband radio system employed by Certified Wireless USB is different from

other wireless technologies on the market because it spreads data transmission over a

very wide frequency spectrum in the form of brief, low-power pulses. In short, this allows

the wireless system to avoid transmission at troublesome frequencies, such as the 5

GHz range (802.11a, some cordless phones). The orthogonal frequency division

multiplexing (OFDM) scheme, developed by the WiMedia Alliance and selected as the

exclusive radio platform for Certified Wireless USB, allows the bit rate and signal

strength of each carrier to adapt so that good channels get used more than those that

hamper transmission.

Certified Wireless USB allows up to 127 devices to connect directly to the host

computer. Unlike wired USB, this is possible without hubs, because there are no wires. 

4. What hardware do I need to use WUSB? Will my existing USB peripherals still work? Think of wireless USB as an additional way in which to connect devices to a computer.

Thus, traditional USB ports are here to stay, at least for the foreseeable future. All of

your current USB peripherals will still utilize the wired USB connection they always

have.

Wireless USB, however, opens up a variety of new types of devices. Wireless USB

hubs, or bridging devices, will allow you to plug wired USB peripherals into the hub, but

the hub itself will enjoy a wireless connection to the computer. In this way, you can

experience the convenience of wireless connectivity without replacing all your USB

peripherals with wireless versions.

To aid in the transition from a world with only wired USB to one where Certified Wireless

USB will one day be supported natively on the motherboard of new computers, the

concept of Device Wire Adapters (DWA) and Host Wire Adapters (HWA) was created.

HWAs are essentially "dongles" that physically connect to the computer via USB 2.0 or

a laptop's CardBus or ExpressCard interface, and provide Wireless USB host capability

to any number of WUSB devices. DWAs, or "Wireless USB hubs", allow existing wired

USB devices to be used wirelessly with a WUSB host.

Over time, the industry will move towards more integrated solutions where any required

hardware is built-in to the computer and adapters will not be necessary. Of course, you

would need a computer so-equipped to enjoy wireless USB built-in. 

5. Where are all the Wireless USB products? Wireless USB products have been late in arriving,

mainly due to manufacturers needing to overcome

technical hurdles inherent in any new technology

launch. But the wait is over, and you can expect to

see numerous product announcements leading up to the Christmas season. While this

is exciting for the industry as a whole, it will be a while before native hardware and

driver support for Certified Wireless USB is built into computers and major operating

systems. Naturally, speed, compatibility and robustness will improve in successive

product generations as the technology becomes more widely adopted and

manufacturers tweak, revise, and redesign their products for optimal performance.

Everything USB will be bringing you a new Wireless USB section soon. For now, here

are the links to some Certified Wireless USB products on this site:

Cables Unlimited Wireless USB Adapter Set  - A low-cost adapter that converts a single USB node to wireless

Imation Wireless Projection Link  - WUSB video solution with zero-install option, Mac compatible

Imation Pro WX Wireless Hard Drive  - A 1.5TB hard drive housed in a Staccato-powered WUSB enclosure

IOGear Wireless USB AV Kit  - Adapter set capable of streaming both 720p to VGA and stereo sound to RCA

Kensington WUSB Dock for Notebooks  - Wireless video, wireless USB audio - 15 feet of freedom

Toshiba DynaDock Wireless USB Dock  - Notebook dock with DisplayLink, 7.1 sound & isochronous USB support

6. Will Wireless USB eventually replace wired USB? Despite rapid advancements in wireless technology through the course of the computing industry, good old wired connections still enjoy speed and some security advantages over their wireless counterparts. It is just that much more straightforward and fast to get electrons traveling nicely down a few pieces of copper than it is to transmit signals through thin air and in the presence of interference. There is simply no chance of an unwanted party connecting to your local USB storage device, for instance, when the cable is directly connected to your PC (provided your networking environment is properly secure).

Wired USB 2.0 and the new USB 3.0 (a.k.a. SuperSpeed USB) standard are not

going away, but will remain the device interconnect standard of choice for the

foreseeable future. The issues of speed and distance pose significant challenges to any

connection standard, but are always an order of magnitude more difficult to solve in a

wireless environment.

Lastly, the issue of cost will likely always favor the wired USB solution over wireless

USB. Interface chips simply are less complex in a wired world, and that allows the cost

of products that contain them to be lower as well. For users who don't need the

convenience and freedom that wireless USB offers, wired USB is here to stay. 

7. What operating systems support Certified Wireless USB? In a nutshell, all major computer operating systems

are planned to support wireless USB. However, at

the moment, wireless USB functionality is provided

only by proprietary software drivers and is largely

device-specific.

As the standard matures and subsequent releases

of your favorite operating system become available,

we expect native wireless USB support to be built in. Products containing DWA and

DHA will utilize custom wireless USB drivers for the foreseeable future.

Microsoft has stated officially (warning: MS DOC) that Windows drivers for the

Wireless Host Controllers Interface (WHCI), Host Wire Adapters (HWA) and Device

Wireless Adapters (DWA) are currently in Alpha. Shipping drivers are said to be

forthcoming, depending on hardware availability and other such factors, although a

specific date for wide-scale availability has not been provided.

Apple has not released any information regarding Mac OS X support for Certified

Wireless USB. In classic Apple fashion, they may be just playing these cards close to

their chest. When some official announcement is made, you can be sure to read it here

on our site. 

8. Is Certified Wireless USB secure?By design, Certified Wireless USB is a very secure method of data transmission. As

with any wireless technology, there is the possibility for data in the air to be available to

other wireless receivers in range with malicious intent. Encryption is incorporated at

multiple layers of the protocol, which forces a secure relationship to be automatically

negotiated between each wireless USB device and the host computer using unique

keys. This type of arrangement provides an extremely high-level of security to the data

link, without passwords for the user to enter or forget. Coming in the updated

specification (version 1.1), first-time device association will be simplified through the use

of Near Field Communication (NFC) capabilities, meaning that devices can be

introduced to their computers by a touch-and-go action.

The inherent low-power nature of the ultra-wideband radios used in Certified Wireless

USB also plays a factor in the security. Since the maximum range is not more than 10

metres, the threat of data being stolen or read by others is limited to those who can be

situated within close proximity to the wireless USB network.

More information about wireless USB bonding and device association methods can be

found here. 

9. Will other wireless technologies interfere with my WUSB devices?The wireless transmission techniques used in Certified Wireless USB promise to be

some of the most robust schemes of their type in the consumer market. Interference

robustness is far better than Wi-Fi. Ultra-wideband signals will not be affected by out-of-

band interferers such as Wi-Fi, Bluetooth, or cordless phones, even at close proximity.

The reason for this is the use of a wide frequency spectrum with extremely low power at

any one given frequency (but high power spectral density) versus "narrowband"

systems which occupy only a small range of dedicated bands.

UWB is very tolerant of interference from other UWB sources but equally important, will

"peacefully" co-exist with other wireless networks such as Wi-Fi and not interfere with

Wi-Fi operation. Put simply, the limited range of UWB will undoubtedly be more of a

limitation for potential users than interference robustness. 

10. What does the future hold for WUSB and what about those competing standards?Over the past few years, several alternate "flavors" of wireless USB have been

developed, none of which play any significant role in the market today.

The first such flavor was released by Cypress Semiconductor in 2003 and is technically

the only version that can be called WirelessUSB [tm] because it is trademarked. It is a

very low-speed, limited "variant" of USB that was primarily targeted as a replacement

for Bluetooth. Its key application lies in the wireless connections of human interface

devices (HIDs) such as mice and keyboards. It uses a proprietary 2.4 GHz radio with a

datarate of only 62.5 kbps. Cypress' WirelessUSB has very limited appeal in today's

consumer electronics and computer industry and is rarely mentioned in mass

publications or on the internet.

The second flavor was pioneered by Freescale

Semiconductor (formerly a division of Motorola,

Inc.), trademarked "CableFree USB", and promoted

by the UWB Forum and its partners. This variant

used an ultra-wideband radio technology called

direct sequence (DS-UWB) and its main advantage

was that it was built on top of the USB 2.0 protocol in use today. This meant that users

could make a seamless transition from wired USB 2.0 or 1.1 to a CableFree wireless

USB system with absolutely no changes required to the computer, operating system, or

software drivers. CableFree USB was a very compelling advancement in 2005 and

2006, and was actually first to market at the Consumer Electronics Show in 2006 with

the multi-award-winning Belkin CableFree USB 4-port hub. Since that time, Freescale

and its CableFree USB promoters have abandoned the market, leaving only one viable

solution remaining: Certified Wireless USB.

True competition for Certified Wireless USB will come primarily from Bluetooth and

IEEE 802.11n (the latest and fastest variant of Wi-Fi).

Bluetooth became popular primarily for low-speed

short-range personal area communications and due

to its extremely low cost of implementation. It uses

the massively crowded 2.4 GHz radio frequency and currently is limited to a maximum

datarate of about 2.1 Mbps. Knowing that the maximum throughput would need to be

able to scale higher to ensure the future viability of Bluetooth, supporters of Bluetooth

selected the OFDM-UWB radio platform for future integration with Bluetooth technology.

This means that future versions of Bluetooth will use very much the same wireless

technology as Certified Wireless USB, with similar high data rate capabilities for

multimedia applications such as video streaming. It will certainly be very interesting to

see how this plays out, and whether Bluetooth and Certified Wireless USB will be able

to co-exist.

802.11n (and its predecessors 802.11g/b/a), are

without question the standard in wireless

networking. Originally developed to address the

problem of deploying Local Area Networks (LANs)

without cabling, it has truly changed the face of mobile computing and is supported by

every major operating system, most gaming consoles, and many mobile devices and

mobile phones. In its latest iteration, 802.11n, data rates in excess of 100 Mbps are

achievable at a range of up to 30m or greater. Starting a few years ago, due to the lack

of any other high-speed wireless protocol, many manufacturers of digital cameras and

printers proceeded to install support for 802.11 networking in order to achieve wireless

data transfer. Certified Wireless USB would have been a more logical choice, but it was

not ready and is still in its infancy.

Introduction of Wireless USB

The Universal Serial Bus (USB), with one billion units in the installed base, is the most successful interface in PC history. Projections are for 3.5 billion interfaces shipped by 2006. Benefiting from exceptionally strong industry support from all market segments, USB continues to evolve as new technologies and products come to market. It is already the de facto interconnect for PCs, and has proliferated into consumer electronics (CE) and mobile devices as well.

The Wireless USB is the first the high speed Personal Wireless Interconnect. Wireless USB will build on the success of wired USB, bringing USB technology into the wireless future. Usage will be targeted at PCs and PC peripherals, consumer electronics and mobile devices. To maintain the same usage and architecture as wired USB, the Wireless USB specification is being defined as a high-speed host-to-device connection. This will enable an easy migration path for today's wired USB solutions.

Wireless USB paper takes a brief look at the widely used interconnect standard, USB and in particular, at the emerging technology of Wireless USB and its requirements and promises.

USB Ports

Just about any computer that you buy today comes with one or more Universal Serial Bus connectors on the back. These USB connectors let you attach everything from mice to printers to your computer quickly and easily. The operating system supports USB as well, so the installation of the device drivers is quick and easy, too. Compared to other ways of connecting devices to your computer (including parallel ports, serial ports and special cards that you install inside the computer's case), USB devices are incredibly simple!

Anyone who has been around computers for more than two or three years knows the problem that the Universal Serial Bus is trying to solve -- in the past, connecting devices to computers has been a real headache!

" Printers connected to parallel printer ports, and most computers only came with one. Things like Zip drives, which need a high-speed connection into the computer, would use the parallel port as well, often with limited success and not much speed.

" Modems used the serial port, but so did some printers and a variety of odd things like Palm Pilots and digital cameras. Most computers have at most two serial ports, and they are very slow in most cases.

" Devices that needed faster connections came with their own cards, which had to fit in a card slot inside the computer's case. Unfortunately, the number of card slots is limited and you needed a Ph.D. to install the software for some of the cards.

The goal of USB is to end all of these headaches. The Universal Serial Bus gives you a single, standardized, easy-to-use way to connect up to 127 devices to a computer.

Just about every peripheral made now comes in a USB version. In fact almost all the devices manufactured today are designed to be interfaced to the computer via the USB ports.

USB Connections

Connecting a USB device to a computer is simple -- you find the USB connector on the back of your machine and plug the USB connector into it. If it is a new device, the operating system auto-detects it and asks for the driver disk. If the device has already been installed, the computer activates it and starts talking to it. USB devices can be connected and disconnected at any time.

USB Features

The Universal Serial Bus has the following features: " The computer acts as the host. " Up to 127 devices can connect to the host, either directly or by way of USB hubs.  " Individual USB cables can run as long as 5 meters; with hubs, devices can be up to 30 meters (six cables' worth) away from the host. " With USB 2.,the bus has a maximum data rate of 480 megabits per second. " A USB cable has two wires for power (+5 volts and ground) and a twisted pair of wires to carry the data. " On the power wires, the computer can supply up to 500 milliamps of power at 5 volts.  " Low-power devices (such as mice) can draw their power directly from the bus. High-power devices (such as printers) have their own power supplies and draw minimal power from the bus. Hubs can have their own power supplies to provide power to devices connected to the hub. " USB devices are hot-swappable, meaning you can plug them into the bus and unplug them any time. " Many USB devices can be put to sleep by the host computer when the computer enters a

power-saving modenbsp;