TABLE OF CONTENTS IEEE802.11b is the prevalent standard across the world. This is down to a number of factors, the most important of which is the compatibility standard (WiFi) introduced by the WiFi Alliance [1] [3] (discussed further in section 3.2.3). The low cost of hardware and its inclusion in many new laptop computers and personal digital assistants (PDAs) has also helped IEEE802.11b become one of the world's most popular wireless networking standards. We will consider the operation of IEEE802.11b in some detail, as this is useful to understand the strengths and weaknesses of current wireless networks.
IEEE802.11b is part of a series of wireless LAN standards, some existing and others under development. These standards differ at the physical layer.
The protocol at the air interface needs to be very resilient to cope with high levels of interference, which will occur from other wireless LAN systems and from the other users of the band. Other wireless LAN systems in the vicinity may well employ a carrier sense mechanism to ensure politeness when attempting to gain access to the medium, but other sources will be less friendly. Many of the different standards are about different physical layer techniques to improve the achievable bit rate, or for different frequency bands.
In networking terms the MAC layer is responsible for overseeing that stations take it in turn to access a shared transmission medium. The shared medium can take the form of physical...
