University: University of Texas at Arlington
Professor: Dr . Jonathan Bredow
Department: Department of Electrical Engineering

MAC Layer simulation of Wireless LAN 802.11x  using OPNET Modeler:

The IEEE 802.11b specification allows for the wireless transmission of approximately 11 Mbps of raw data at distances upto several hundred feet over the 2.4 GHz unlicensed ISM band. The distance depends on impediments, materials, and line of sight.

802.11b is an extension of Ethernet to wireless communication, and as such is ecumenical about the kinds of data that pass over it. It's primarily used for TCP/IP. PCs and Macs may communicate over 802.11b, using equipment from a variety of vendors. The client hardware is typically a PC card or a PCI card, although USB and other forms of 802.11b radios are also being introduced. 

Each radio may act, depending on software, as a hub or for computer-to-computer transmission, but it's much more common that a WLAN (wireless local area network) installation uses one or more access points, which are dedicated stand-alone hardware with typically more powerful antennae. The access point often includes routing, DHCP server, NAT, and other features necessary for small to large business operation. The standard is backwards compatible to earlier specifications, known as 802.11, allowing speeds of 1, 2, 5.5 and 11 Mbps on the same transmitters.

Several new, incompatible protocols are in the process of being released, including 802.11a (54 Mbps over the 5 GHz band), 802.11g (22 Mbps over 2.4 GHz), and Texas Instruments' PBCC 22 Mbps standard.

OPNET Modeler is being used by Masters Students at our university for research in the areas of Wireless LAN's 802.11a and 802.11b. Issues such as packet throughput, delay, retransmission etc for different load conditions and Q0S are being studied. We are thankful to OPNET for their continued support to our research projects.