A Wireless Local Area Network
Using these devices users can access shared information conveniently without having to plug in and connect to other devices physically.
The transmission of data between devices in the network takes place by the simple process of modulation with radio frequencies acting as carriers of the information being transmitted. The RF is modulated according to the information signal and carried to the receiving end. At the receiving end, the exact information is extracted from the modulated signal by the process of demodulation. A number of signals can be transmitted through air at the same time provided that their frequencies have a considerable gap between them. In other words, the frequency of operation should be different and they will not interfere. There are one or more devices known as ‘access points’ through which the wireless devices communicate. An access point (AP) is a simple transmitter/receiver or ‘Transceiver’.
A wireless network interface card (NIC) is required to access a wireless network that is available in various forms. Nowadays devices are available with built-in NICs. But they can also be installed separately later. These NICs also require necessary software drivers to be installed for their functioning.
Narrowband WLAN’s keep the bandwidth of the radio frequency signal as narrower as possible, in order to just pass the information. Although the distance between the devices is reasonable the speeds achieved are not as good as required by the corporate users. A general problem that could arise in WLAN’s is the interference, which can be overcome by allotting different frequencies to different individuals. In this case, since the bandwidth is narrow, interference can very well be avoided.
These WLANs use wideband RF. The use of wideband signal helps in attaining greater speeds. The most popular WLAN being used is 802.11b attaining a speed of about 11 Mbps. With the advancement of technology, the speeds have been boosted even up to 50 Mbps and more. A disadvantage with spread spectrum WLAN is the reduction of reliability, integrity, and security. Since the wideband signal is used, therefore it is obviously easier to detect it by an unauthorized person, making it less secure. .