The 802.11b standard operates with the Higher Speed Physical Layer in the ISM band at 2.4 GHz. The 802.11 standard dates back to 1997 and operates with a channel bandwidth of 20 MHz. Transmission rates are available at 5.5 Mbit/s, 11 Mbit/s and 20 Mbit/s. Complementary Code Keying( CCK) is used as the modulation technique, and this is done exclusively by means of spread spectrum technology( DSSS).
The standard also takes security-related aspects into account. For example, the WEPA algorithm is used for encryption, which prevents data packets from being decrypted by other stations. The encryption works with 40 bits or 128 bits with RC4 algorithm. In addition, network access is secured by system identification, and the radio transmission methods mean that the radio signals are either transmitted in a constant frequency change or scrambled.
The standard provides for three types of connection: Point-to-point connection using directional radio, point-to- multipoint connection using access points( AP), and an unstructured access mode.
WLANs based on 802.11b comply with WiFi 1 after certification by the WiFi Alliance. WiFi certification confirms the interoperability ofWLAN products that operate in accordance with the 802.11b standard. The 802.11b standard is obsolete and is hardly used anymore.