WPANs and Ad Hoc Networking

WPANs and Ad Hoc Networking
It is useful to describe wideband wireless local access technologies as falling into two
categories, WLANs and WPANs. Each of these technology categories has been the
subject of considerable standardization effort. In this section we provide an overview
of WPAN activities. In recent years, WPANs have been differentiated from WLANs by their smaller area of coverage, ad-hoc-only topology, plug-and-play architecture,
support of voice and data devices, and low power consumption. WPANs originated as
BodyLANs that connect sensors and information devices attached to the body or to
clothing. In military applications, wireless connectivity is provided to other personnel
or to data collection stations. In commercial applications, WPANs can provide interconnection
among personal electronic devices such as laptops, notepads, and cell phones.
The very first personal area network to be announced was the BodyLAN, which
emerged from a DARPA-sponsored project in the mid-1990s. BodyLAN was a lowpower,
small, inexpensive wireless PAN with modest bandwidth that could connect
personal devices in many collocated systems within a range of about 5 ft [Den96].
Motivated by the BodyLAN project, a WPAN group was started in June 1997 as
part of the IEEE 802.11 standardization activity. In January 1998 the WPAN group
published the original functionality requirement. In May 1998 the study group invited
participation from WATM, Bluetooth, HomeRF, BRAN (HIPERLAN), IrDA (IR shortrange
access), IETF (Internet standardization), and WLANA (a marketing alliance for
WLAN companies in the United States). Only the HomeRF and Bluetooth groups
responded to the invitations. In March 1998, the Home RF group was formed. In
May 1998 the Bluetooth development was announced and the Bluetooth special group
was formed within the WPAN group [Sie00]. In March 1999, the IEEE 802.15 group
was approved as a separate initiative in the 802 community to handle WPAN standardization.
Currently, IEEE 802.15 WPAN has four task groups: Bluetooth (TG1),
coexistence (TG2), high data rate (TG3), and low data rate (TG4). Bluetooth has been
selected as the base specification for IEEE 802.15. In the remainder of this chapter we
provide an overview of the WPAN, HomeRF, and Bluetooth activities.