Hardware Reference
In-Depth Information
might not be available. Using this standard, devices such as digital video recorders can
connect to other recorders to transfer recorded movies or shows, items such as personal
organizers can transfer data to other organizers, and so on. USB On-The-Go greatly en-
hances the usage and capabilities of USB, both in the PC and in the consumer electronics
markets. USB On-The-Go has been included in some of the latest smartphones, allowing
them to easily and directly interface to USB devices such as flash drives, without the use
of a PC.
Wireless USB
Wireless USB (WUSB) is just what the name denotes—USB without wires. WUSB is
basedonultrawideband(UWB)radiotechnology,whichthemilitaryoriginallydeveloped
in 1962 for secure radio communications and radar use. Recognizing the usefulness of
thisradiotechnologyforthepublic,in2002theFederalCommunicationsCommissionre-
leased frequencies from 3.1GHz to 10.6GHz for general-purpose UWB use.
In June 2003, a group called the Multiband OFDM (orthogonal frequency division multi-
plexing) Alliance Special Interest Group (MBOA-SIG) formed to develop a UWB phys-
ical layer interface standard. The MBOA-SIG completed its UWB physical layer 1.0 spe-
cification in November 2004 and subsequently merged with another group called the
WiMedia Alliance in March 2005. The WiMedia Alliance had originally formed in 2002
to promote the standardization and adoption of UWB wireless standards.
InFebruary2004,severalcompanies,includingAgere,HP,Intel,Microsoft,NEC,Philips,
andSamsung,togetherannouncedtheformationoftheWirelessUSBPromoterGroupand
began working on the WUSB specification, which would use the common WiMedia MB-
OFDM (multiband orthogonal frequency division multiplexing) UWB radio platform for
the physical connection layer. The WUSB Promoter Group subsequently developed and
released the WUSB 1.0 specification on May 12, 2005. Wireless USB 1.1 was introduced
on September 29, 2010, and included several improvements such as UWB support for
frequencies 6GHz and above, improved power management, and support for Near Field
Communications (NFC) and proximity-based association, which allows for easier install-
ation and configuration.
WUSB devices are now certified to conform to the standard by the USB Implementers
Forumandenablehigh-speedwirelessconnectivitybyadaptingUSBprotocolstotheMB-
OFDM UWB radio platform as developed by the WiMedia Alliance. Certified WUSB
devices carry the official Wireless USB logo shown in
Figure 14.13
.
Figure 14.13
The Wireless USB logo carried by devices certified to comply with the Wireless USB spe-
cification.
