Briefly describe the 802.11b (2.4GHz) and 802.11a (5GHz) frequency ranges with respect to the channels available in them to transmit wireless data.

2.4Ghz Band

• Only channels 1-11 are used in US. It gives us a range 72Mhz (2.401- 2.473) to transmit data in the 2.4GHz spectrum.
• Only channels 1,6 and 11 are non overlapping and hence used when we deploy the Access Points.
• Channel Width of each channel is 22MHz.
• 2.4GHz is also used by microwave ovens, cordless phones, baby monitors and wireless video cameras.
• This frequency range is heaviliy used and is the potential for interference.

5GHz Band

• 5GHz have 4 UNII bands (Unlicensed National Information Infrastructure Bands).
• UNII-1 (lower) band ranges from 5.15-5.25 GHz and has 4 channels. All the channels are non-overlapping. (Range: 100MHz)
• UNII-2 (Middle) band ranges from 5.25-5.35 GHz and has 4 channels. All the channels are non-overlapping. (Range: 100MHz)
• UNII-2 Extended (Extended) band ranges from 5.470-5.725 GHz and has 11 channels. All the channels are non-overlapping. (Range: 255MHz)
• UNII-3 (Upper) band ranges from 5.725-5.825 GHz and has 4 channels. All the channels are non-overlapping. (Range: 100MHz)
• Total of 23 channels are present in the 5GHz range and all the channels are non-overlapping and we get a range of 550MHz to transmit data.
• Channel Width of each channel is 20Mhz.

Note: In 2.4ghz we get a frequency range of 72Mhz whereas in 5GHz we get a frequency range of 555Mhz to transmit data.