NIST RESEARCHERS LEAD DEVELOPMENT OF STANDARDS FOR WIRELESS PERSONAL AREA NETWORKS.A growing number of industry groups are developing specifications for Wireless Personal Area Networks (WPAN (Wireless Personal Area Network) A wireless network that is typically limited to a small cell radius. In an office environment, a WPAN would be used to transfer data between a handheld device and desktop machine or printer. ), such as the specifications developed by the Bluetooth Special Interest Group The Bluetooth Special Interest Group (SIG) is the body that oversees the development of Bluetooth standards and the licensing of the Bluetooth technologies and trademarks to manufacturers. (SIG), HomeRF, and IEEE (Institute of Electrical and Electronics Engineers, New York, www.ieee.org) A membership organization that includes engineers, scientists and students in electronics and allied fields. 802.15. WPANs, essentially cable replacement technologies, allow closely located digital devices to exchange information. Most technologies considered for WPANs employ an unlicensed radio frequency band in the range of 2.4 GHz (the so-called industrial, scientific, and medical, or ISM, band). This same frequency range also is used by existing standards for wireless local area networks (WLAN See wireless LAN.
WLAN - wireless local area network ), for example IEEE 802.11. As the number of technologies using the ISM band increases, concern arises about the possibly deleterious effects of mutual electromagnetic interference See EMI. .
Designing wireless protocols that can share this scarce spectrum presents a key challenge in the design of WPANs.
A team of NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. researchers made significant contributions to industry's ongoing efforts to standardize WPAN technology in the IEEE 802.15. Specific contributions include: (1) modeling and validation of the Bluetooth protocol specifications, (2) assessment of interference among wireless devices operating in the 2.4 GHz band, and (3) development and evaluation of coexistence mechanisms for wireless devices sharing the same spectrum.
NIST researchers led efforts within the IEEE 802.15 Task Group on Coexistence to study, characterize, and quantify the radio-frequency interference between Bluetooth and the now widely deployed IEEE 802.11b WLAN devices. Further, NIST researchers have proposed mechanisms and technical solutions to allow these devices, emitting radio frequency energy in the same 2.4 GHz frequency band, to coexist and operate effectively when in close proximity. Proposed solutions from the NIST researchers, for both the Medium Access Control (MAC) and Physical (PHY See physical layer and physical. ) layers, were combined with contributions by private companies and then adopted by the IEEE 802.15 as the basis for a document on recommended practices for device designers.
In another contribution, NIST researchers used a formal specification technique, known as the Specification and Description Language Specification and Description Language (SDL) is a specification language targeted at the unambiguous specification and description of the behaviour of reactive and distributed systems. It is defined by the ITU-T (Recommendation Z.100. (SDL (Specification and Description Language) A modeling language used to describe real time systems. It is widely used to model state machines in the telecommunications, aviation, automotive and medical industries. ), to model and validate the Bluetooth protocols for link control and MAC. Using these models, numerous flaws in the original protocol specifications were identified, resulting in hundreds of suggestions for improvement to the Bluetooth specifications. These SDL models, created by NIST, will be published as part of the official 802.15 specifications, significantly clarifying the intent of the standard and thereby improving its testability.
Due to the growing importance of the scarce unlicensed wireless spectrum, NIST's work continues within the IEEE 802.15 Task Group on Coexistence. The NIST team continues to lead industry work in this area, concentrating on modeling the MAC and the PHY layers. The studies published by NIST on the interference between various technologies under different data traffic conditions and deployment scenarios have contributed to the task group's bimonthly bi·month·ly
1. Happening every two months.
2. Happening twice a month; semimonthly.
1. Once every two months.
2. Twice a month; semimonthly.
n. pl. meetings and presented in several professional conferences. NIST researchers also serve as editors of the Recommended Practices document on the coexistence of various wireless devices in the 2.4 GHz band. IEEE 802.15 is expected to release this document later this year.
Beyond the IEEE 802.15, NIST is working with other industry partners to further disseminate relevant technical results.