Wireless networking involves connecting one computer to another in a peer-to-peer network or using an access point to connect a wireless local area network (LAN) to a wired LAN. The use of an access point allows the wireless computers to use the wired LAN resources including an existing Internet connection. Wireless LAN connection allows for flexibility and mobility but also can be used to connect many computers when wiring would be inconvenient and expensive.
An access point is a transmitter/receiver (transceiver) device that connects individual computers to a wired network via standard cabling. The access point receives, buffers and transmits data between the wireless LAN and the wired network infrastructure. Each access point can support a small group of users (around a dozen) at the same time who may be anywhere from 200-300 feet away inside a building or up to 1,000 feet away outside.
Wireless LANs use electromagnetic airwaves (radio frequency or infrared light pulses) to transmit and receive data through the air to the access point without any physical connectivity. The access point then sends and accepts data through regular wiring of Ethernet cables. Data to be sent across these networks is first superimposed on the radio carrier through modulation (a process in which the data is broken down into smaller parts for transmission). The radio signal can occupy more than one frequency in order to increase communication speed.
The Institute of Electrical and Electronics Engineers creased wireless-Ethernet specification know as IEEE 802.11. This specification is useful because it allows for multi-vendor interoperability. The specification also designated two methods of wireless communication; direct-sequence spread spectrum (DSSS) and frequency-hoping spread spectrum (FHSS). DSSS uses modulation to send each data packet simultaneously on different frequencies. FHSS sends a short burst of data and then "hops" to another frequency to send another short burst. FHSS uses much less bandwidth than DSSS but also can be a lot slower.
Individual computers must have a wireless-LAN adapter such as a wireless NIC card in order to communicate with an access point. Wireless cards are drivers that are usually external and thus can be inserted and removed as the user desires. A portion of the card remains outside of the computer and functions as an antenna to direct the data airwaves from the source (access point) to the end user on a computer and vice versa. Other computers may come with an integrated wireless adapter that is completely internal and does not need to be installed.
Wireless cards (as well as access points) are manufactured by many different vendors and each different type must be installed differently. Directions for the specific card to be used should be followed. After installation, end users must register their wireless cards just as they would Ethernet cards to gain access to LAN networks. Once registration has been completed, users may move about the area of wireless coverage without having to reregister. For directions on how to install a Cisco Wireless 340 PC Card and register it to the UNC network visit ATN's help page. Users with integrated wireless adapters must also register for network use. Instructions for connecting to the UNC network with integrated adaptors can also be found on ATN's help page.