written 8.4 years ago by | • modified 8.4 years ago |
Mumbai University > Computer Engineering > Sem6 > Mobile Communication and Computing
Marks: 10M
Year: Dec 2015
written 8.4 years ago by | • modified 8.4 years ago |
Mumbai University > Computer Engineering > Sem6 > Mobile Communication and Computing
Marks: 10M
Year: Dec 2015
written 8.4 years ago by |
What is IEEE 802.11?
In 1997, IEEE developed an international standard for WLANs, i.e. IEEE 802.11. Like other IEEE 802 standards, this layer also focuses on the bottom two layers of the OSI model i.e. physical layer and data link layer.
The objective of IEEE 802.11 was to define a medium access control (MAC) sublayer, MAC management protocol and service and 3 physical layers for wireless connectivity of fixed, portable and movable devices.
- | IEEE 802.11 | IEEE 802.11a | IEEE 802.11b | IEEE 802.11g | IEEE 802.11n |
---|---|---|---|---|---|
Applications | WLAN | WLAN | WLAN | ||
Frequency band | 2.4 GHz | 2.4 GHz | 5 GHz | 2.4 | 2.4, 5 GHz |
Max. Data Rate | 2 Mbps | 54 Mbps | 11 Mbps | 54 Mbps | 600 Mbps |
Rate | |||||
Approval date | 1997 | July 1999 | July 1999 | June 2003 | August 2006 |
Modulation | DSSS , FHSS | OFDM | DSSS or CCK | DSSS or CCK or OFDM | DSSS or CCK or OFDM |
Channel width | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz or 40 MHz |
Typical range | 66 feet | 75 feet | 100 feet | 150 feet | 150 feet |
Antenna configuration | 1x1 SISO | 1x1 SISO | 1x1 SISO | 1x1 SISO(Single Input-Single Output) | 4x4 MIMO (Multiple Input-Multiple Output) |
IEEE 802.11i is mainly designed for enhanced security purposes. It addresses two main weaknesses of wireless security networks which are encryption and authentication.
Encryption is accomplished by replacing WEP’s original PRNG RC4 algo by stronger cipher that performs three steps on every block of data.
The authentication and key management is accomplished by the IEEE 802.1x standard.