802.11b describes the 2nd generation of the WiFi. Learn here more about the standard.
The General Specifications of 802.11b
802.11b or IEEE 802.11b-1999 is an amendment to the IEEE 802.11. With this IEEE standard, WLAN technology gets the name Wi-Fi. It works in the frequency of 2.4 GHz and the maximum speed is 11 Mbps.
Read more about the WiFi on what does WiFi stand for. What is WLAN and what is there a difference between WiFi and WLAN you can read on what is WiFi? What is WLAN? Is There a Difference Between Those Two?
The Frequency Band of 2.4 GHz
The frequency of 2.4 GHz is unregulated frequency. Providers do not have to pay the license for using this band. Since there are lots of other wireless technologies that work on the same band, the interference could occur. Microwave ovens, cordless phones and Bluetooth devices work on the same band.
The Modulation of 802.11b
The standard uses DSSS (Direct-sequence spread spectrum) and CCK (Complementary Code Keying) on the frequency 2.4 to 2.483 GHZ. DSSS is the modulation technique in which transmitted signal takes up more bandwidth than the information signal that is being modulated. The name spread spectrum comes from the fact that the carrier signal occurs over the entire spectrum of the transmitting frequency.
Its range in the indoor environment is about 35 meters (117 feet), and 100 meters (333 feet) in an outdoor environment.
The Channels of the Amendment
From the table, you can observe that the standard has been divided into 14 channels. Unlike the 802.11a standard, the same maximum power for all channels is 100 mW. All the channels have the same band gap of 5MHz or 0.005 GHz, except the frequency gap between last two channels. The frequency gap between channel 13 and channel 14 is 12 MHz.