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Wireless Protocols

Wireless Protocols

Jason D. Knight

As with all data transmission technologies, protocols govern the manner in which information is transferred between stations. A protocol is simply an agreed upon standard that all parties use to ensure that different devices can communicate with each other. Wireless protocols can be discussed on their own, and where they fit in the OSI protocol suite. For the sake of clarity, we will limit our discussion to wireless network implementations.
Wireless protocols typically reside in layers 1 and 2, the application and presentation layers, respectively, of the OSI model. These two layers help direct how the data is gathered from the end station and prepared for transmission.
The main wireless protocol are: IEEE 802.11 covering wireless Ethernet; 802.15 dealing with wireless personal area networks (WPAN), including Bluetooth technology; and 802.16 for broadband wireless access.
802.11
The IEEE 802.11 specification family consists of four different, primary specifications:
• 802.11 – applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band using either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS).
• 802.11a – an extension to 802.11 that applies to wireless LANs and provides up to 54 Mbps in the 5GHz band. 802.11a uses an orthogonal frequency division multiplexing encoding scheme rather than FHSS or DSSS.
• 802.11b (also referred to as 802.11 High Rate or Wi-Fi) – an extension to 802.11 that applies to wireless LANS and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1 Mbps) in the 2.4 GHz band. 802.11b uses only DSSS. 802.11b was a 1999 ratification to the original 802.11 standard, allowing wireless functionality comparable to Ethernet.
• 802.11g – applies to wireless LANs and provides 20+ Mbps in the 2.4 GHz band.
• 802.11n – applies to future standards for wireless data transmission that promises a maximum bandwidth of 108 Mbps through...