Wireless USB Technology

Wireless USB Technology

Imagine if all the devices in a home office -- such as printer, scanner, external hard drive, and

digital camera -- could be connected to your PC without any wires. Imagine if all the

components for an entire home entertainment center could be set up and connected without a

single wire. Imagine if digital pictures could be transferred to a photo print kiosk for instant

printing without the need for a cable. These are just some of the possible scenarios for highspeed

wireless USB (WUSB) connectivity, the latest technology developed to bring even

greater convenience and mobility to devices.

Universal serial bus (USB) technology has been a popular connection type for PCs and it's

migrating into consumer electronic (CE) and mobile devices. Now this high-speed and effective

connection interface is unwiring to provide the functionality of wired USB without the burden of

cables. This next iteration of USB technology is the focus of the new Wireless USB Promoter

Group, which will define the specifications that will eventually provide standards for the

technology.

WUSB Topology

The fundamental relationship in WUSB is a hub and spoke topology, as shown in Figure . In

this topology, the host initiates all the data traffic among the devices connected to it, allotting

time slots and data bandwidth to each device connected. These relationships are referred to

as clusters. The connections are point-to-point and directed between the WUSB host and

WUSB device.

The WUSB host can logically connect to a maximum of 127 WUSB devices, considered an

informal WUSB cluster. WUSB clusters coexist within an overlapping spatial environment with

minimum interference, thus allowing a number of other WUSB clusters to be present within the

same radio cell.

Topology will support a dual role model where a device can also support limited host

capabilities. This model allows mobile devices to access services with a central host

supporting the services (i.e., printers and viewers). This model also allows a device to access

data outside an existing cluster it may currently be connected to by creating a second cluster

as a limited host.

Additionally, high spatial capacity in small areas is needed to enable multiple device access to

high bandwidth concurrently. Multiple channel activities may take place within a given area.

The topology will support multiple clusters in the same area. The number of clusters to be

supported is still being determined

Design Considerations

There are several architectural considerations in developing WUSB. In addition to providing

wireless connectivity, WUSB must be backwards compatible with wired USB and provide a

bridge to wired USB devices. Also, the host and solutions will need to enable the exchange of

data between clusters or devices not related to the same host.

Low-cost implementation of WUSB will also be important to the successful integration of the

technology. Implementation will follow the wired USB connectivity models as closely as

possible to reduce development time and to preserve the low-cost, easy-to-use model, which

has become pervasive in the PC industry.

Performance

WUSB performance at launch will provide adequate bandwidth to meet the requirements of a

typical user experience with wired connections. The 480 Mbps initial target bandwidth of

WUSB is comparable to the current wired USB 2.0 standard. With 480 Mbps being the initial

target, WUSB specifications will allow for generation steps of data throughput as the ultra

wideband radio evolves and with future process technologies, exceeding limits of 1 Gbps.

The specification is intended for WUSB to operate as a wire replacement with targeted usage

models for cluster connectivity to the host and device-to-device connectivity at less than 10

meters. The interface will support quality delivery of rich digital multimedia formats, including

audio and video, and will be capable of high rate streaming (isochronous transfers).

Summary

As the latest iteration of USB technology, wireless USB (WUSB) will offer the same

functionality as standard wired USB devices but without the cabling. As the new Wireless USB

Promoter Group prepares to develop the specifications that will help standardize the

technology, the industry is planning products that can take advantage of the convenience and

mobility that this new device interconnect will offer