Bluetooth
Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. Connections between Bluetooth devices allow these devices to communicate wirelessly through short-range, ad hoc networks. Bluetooth operates in the 2.4 GHz unlicensed ISM band.
Note:
Industrial, scientific and medical (ISM) band is a part of the radio spectrum that can be used by anybody without a license in most countries. In the U.S, the 902-928 MHz, 2.4 GHz and 5.7-5.8 GHz bands were initially used for machines that emitted radio frequencies, such as RF welders, industrial heaters and microwave ovens, but not for radio communications. In 1985, the FCC Rules opened up the ISM bands for wireless LANs and mobile communications. Nowadays, numerous applications use this band, including cordless phones, wireless garage door openers, wireless microphones, vehicle tracking, amateur radio…
WiMAX
Worldwide Interoperability for Microwave Access (WiMax) is defined by the WiMax forum and standardized by the IEEE 802.16 suite. The most current standard is 802.16e.
Operates in two separate frequency bands, 2-11 GHz and 10-66 GHz
At the higher frequencies, line of sight (LOS) is required – point-to-point links only
In the lower region, the signals propagate without the requirement for line of sight (NLOS) to customers
Basic Service Set (BSS)
A group of stations that share an access point are said to be part of one BSS.
Extended Service Set (ESS)
Some WLANs are large enough to require multiple access points. A group of access points connected to the same WLAN are known as an ESS. Within an ESS, a client can associate with any one of many access points that use the same Extended service set identifier (ESSID). That allows users to roam about an office without losing wireless connection.