Wireless LAN

The notebook is connected to the wireless access point using a PC card wireless card.

A diagram showing a Wi-Fi network

In computing, Wireless LAN (WLAN) or Wireless local area network is a term to refer to a Local Area Network that does not need cables to connect the different devices. Instead, radio waves and IEEE 802.11 are used to communicate.

Benefits of Wireless LANs

• People can access the network from where they want; they are no longer limited by the length of the cable
• Some places and vehicles have a Wireless LAN hotspot. This lets people access the internet even outside their normal work environment, for example in a restaurant or train.
• Setting up a wireless LAN can be done with one box called wireless access point or wireless router. This box can handle many connections at the same time. Wired networks require cables to be laid. This can be difficult for certain places.
• Access points can serve a varying number of computers.

Disadvantages of Wireless LANs

• Wireless LANs use radio waves to communicate. Special care needs to be taken to encrypt information.
• The signal is noisier than on wires, and more bandwidth needs to be spent on error correction.
• A typical IEEE 802.11 access point has A range of meters from where devices can connect. To extend the range more access points are needed.
• There are many reliability problems, especially those connected to interference from other devices.
• Wireless LANs are much slower than wired ones; this may not matter for most users though, because the bottleneck in a home network is usually the speed of the ADSL line or other Internet connection.

Technologies used

Today, most technologies used for WLANs use Orthogonal Frequency Division Multiplexing. This means that several frequencies are used at the same time. Signals that are close to each other, but that belong to different channels do not disturb each other, as they use different coding schemes. Depending on the material used, it is possible to cover between 30 metres and 100 metres indoors; outdoors, the range is about 100-300m, if there are no obstacles.

Wireless LAN Media

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  54 Mbit/s WLAN PCI Card (802.11g)

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  Peer-to-Peer or ad hoc wireless LAN

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  Hidden node problem: Devices A and C are both communicating with B, but are unaware of each other

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  Roaming among Wireless Local Area Networks