Most companies focus their initial efforts on creating a wireless USB standard in cooperation with the USB Implementer's Forum, which manages that standard. The wireless USB standard would then be built on top of the WiMedia radio technology standard. The standards are a good match because the USB interface can go to 480 Mbits/s. The standard speed for typical peripheral connections is 12 Mbits/s, while older versions were only good to 1.5 Mbits/s.
There are several ways to implement wireless USB. The ultimate goal is to embed wireless USB into every laptop, printer, and other computer device, leading to automatic linkup and function without cables. While a few early embedded wireless USB devices exist, like some Dell, Lenovo, and Toshiba laptops, initial implementation will be with UWB wireless USB dongles or adapters. Wireless USB hubs that accept four USB connections will also be popular (Fig. 2).
Many companies are looking at UWB as the newer and faster Bluetooth 3.0. With UWB as the new Bluetooth physical layer (PHY), Bluetooth can extend its reach into other products. The Bluetooth protocol stack is simply built on top of the WiMedia platform (Fig. 3).
A protocol adaption layer (PAL) interfaces the platform to the specific technology stack. PALs can be built to make the UWB PHY and media access controller (MAC) work with IEEE 1394, HDVI, and WiNet. For instance, WiNet is the WiMedia Alliance's own unique PAL for interfacing to Internet Protocol (IP) devices, including Ethernet.
Rumor has it that UWB will be adopted as a higher-speed option to work with the 802.15.4 personal-area-network (PAN) standard. Mesh networks based on 802.15.4 and ZigBee are inherently slow, as most sensor and control nets don't need the speed. But they're a great option for applications that may need a bit more speed. UWB is inherently low-power, so it's a good fit in mesh networks. UWB also may appear in cell phones to stream photos or video.
While the WiMedia Alliance and the USB Implementer's Forum developed the standards, the WiMedia specifications have been adopted by the European Computer Manufacturer's Association (ECMA) International as ECMA 368 and 369. In turn, it has become the International Standards Organization (ISO) standard.
PRODUCT PROFILES
Spun off from UWB pioneer Time Domain, Alereon now offers the AL5100 RF transceiver and the AL5300 MAC and baseband processor chips. Also, Alereon claims its AL4000-certified wireless USB chip set is the first RF chip set to cover the full 3.1- to 10.6-GHz band. This feature will make the chips a good fit for companies building products to comply with varying Asian and European frequency standards.
Artimi's A-150 UWB MAC chip works with several UWB RF transceivers. The chip's really low power consumption suits it for laptop and cell-phone applications. Artimi also has proposed a mesh network using UWB. This makes sense with UWB's short range, since mesh can greatly improve data rates by linking nodes over shorter distances. The mesh extends the overall range while maintaining data rate.
Blue7 Communications' Windeo Intelligent Array Radio two-chip set has all of the usual features and supports up to three antennas. This improves link reliability in non-line-of-sight (NLOS) environments. It also extends the range as well as provides an overall boost in data rate. Blue7 says the chip set can achieve a 106.7-Mbit/s rate at up to 20 m, which is well beyond the capability of most other chip sets.
Bluetooth chip leader CSR recently committed to the new Bluetooth UWB PHY. Though the company doesn't have a product yet, there's no doubt we can expect to see an advanced Bluetooth UWB chip set in the near future.
Focus Enhancements, which makes video decoder chips, is primarily interested in UWB for video applications. Its Telaria TT1013 UWB chip operates from 3.1 to 7.4 GHz. The radio and MAC baseband are in one chip, which can interface with almost anything. As a result, it can be used in all UWB applications, including wireless USB, digital cameras, and camcorders. It includes AES-128 encryption.
Intel was one of the early pioneers in the UWB movement. Today, its UWB Link 1480 MAC chip is WiMedia-compliant and useful in wireless USB applications.
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