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TANDBERG TANDBERG and Wireless LANs
1. Overview Of Wireless Standards
1.1 802.11 Wireless Ethernet
Ethernet was pioneered by Xerox in the 1970’s and was in fact a registered trademark of
Xerox Corporation. After further development, the technology was improved and became
known as Ethernet II. Xerox, with the help from Digital and Intel began establishing and
publishing the standards. Realizing the international community would not recognize the
standard, IEEE was charged with formalizing the standard along with other LAN
technologies. The 802 committee was assembled to investigate Ethernet, Token Ring, Fiber
Optic, and other LAN technology.
1.1.1 802.11a
The 802.11a specification applies to wireless ATM systems and is primarily used in access
hubs. This specification operates at 5GHz and 6GHz. By using a modulation scheme of
orthogonal frequency division multiplexing (OFDM), 802.11a can achieve speeds up to
54Mbps. However, speeds of 6Mbps, 12Mbps and 24Mbps are more common.
1.1.2 802.11b
The 802.11b specification, also known as Wi-Fi, uses complementary code keying (CCK)
phase-shift keying (PSK) instead of the traditional phase-shift keying (PSK) used in 802.11.
The use of CCK allows for higher data speeds and less interference to multipath-propagation
interference. 802.11b operates at 2.4GHz and allows for speeds up to 11Mbps.
1.1.3 802.11g
The 802.11g specification allows for speeds up to 54Mbps over short distances. The
802.11g standard also operates at 2.4GHz and is compatible with 802.11b.
1.2 BlueTooth
BlueTooth is another wireless standard named for the 10
th
Century Viking king Harald
Blåtand of Denmark. The Bluetooth wireless specification defines a low-power, low-cost
technology that provides a standardized platform for eliminating cables between mobile
devices and facilitating connections between products. Bluetooth operates at the unlicensed
2.4GHz frequency. The standard uses a spread spectrum, frequency hopping, full-duplex
signal at up to 1600 hops/sec. The signal hops among 79 frequencies at 1 MHz intervals to
give a high degree of interference immunity.