Wireless Local Area Network (WLANs) and Wireless Personal Area Network (WPANs) technologies are
emerging today as local wireless communication systems.
While both WPANs and WLANs allow a number of independent devices to communicate, WPANs are mainly
intended as cable replacement technologies and communications are normally confined to a person or object and
extend up to 10 meters in all directions. This is in contrast to WLANs that typically cover a moderately sized
geographic area such as a single building, or campus. WLANs operate in the 100 meter range and are intended to
augment rather than replace traditional wired LANs.
Today most radio technologies considered by WPANs (Bluetooth Special Interest Group, IEEE 802.15, WiMedia
Alliance, and Zigbee Alliance) employ the 2.4 GHz ISM frequency band. In addition both WPANs and WLANs devices, which
implement the IEEE 802.11 standard specifications, will be sharing the same frequency band. It is anticipated that some
interference will result from all these technologies operating in the same environment. WLAN devices operating in proximity
to WPAN devices may significantly impact the performance of WPAN and vice versa.
In November 1999, the IEEE 802.15.2 Coexistence Task Group was formed in order to evaluate the performance of
Bluetooth devices interfering with WLAN devices and to develop a model for coexistence. The results consist of a set of
recommended practices and modifications to the Bluetooth and the IEEE 802.11 standard specifications that allow the proper
operation of these protocols in a cooperating way. The approach consists of using modeling and simulation of both the
medium access control (MAC) and physical (PHY) layers, analysis and data collected from field experiments.
The IEEE 802.15.2 recommended practice document was completed August 27, 2003.
NIST is continuing the coexistence work by participating in the IEEE 802.19 Technical Advisory Group (TAG),
which is tasked with developing a coexistence methodology, which the other IEEE 802 wireless working groups can use to
demonstrate coexistence among other IEEE 802 devices.
Our achievements so far consisted of:
- Building a detailed simulation platform consisting of the MAC, PHY and channel models for the IEEE 802.11
and Bluetooth protocols.
- Conducting the performance evaluation and quantifying the impact of interference on the performance of Bluetooth
and IEEE 802.11 devices operating in the same environment.
- Developing coexistence mechanisms including MAC scheduling algorithms and PHY layer interference mitigation techniques.
- Download the simulation models developed in
OPNET and C.
- SDL Behavior models of the protocols in the various drafts of IEEE 802.15.4.
- The SDL behavior models created for the IEEE 802.15.1 are posted on the IEEE web pages.
|Related IEEE 802.15 contributions for this project: |