Wireless technologies is emerging as a one of the rapidly growthing technology.It provides unintrupted access to the network for all of the campus community. Every one increasingly want un-tethered network access for general-purpose,for example,people wants laptop computers equipped with wireless Ethernet cards.Wireless is being adopted for many new applications: to connect computers, to allow remote monitoring and data acquisition, to provide access control and security etc.
There are various applications for all the different wireless technologies,but we can divided into the following:
* Voice and messaging,
* Hand-held and other Internet-enabled devices, and
* Data Networking.
Voice and Messaging
Cell phones, pagers, and commercial two-way business radios can access voice and messaging services. These devices may be based on analog or digital standards.The analog standard is AMPS. Digital standards are GSM,TDMA, or CDMA.
Generaly, devices operate within networks that provide metropolitan, statewide, or nationwide coverage and operate in different frequency bands which are allocated by the FCC. Presently in the U.S., these networks operate throughput rates up to 16 kilobits per second (Kbps).
Hand-held and Internet-enabled devices
Cell phones and Personal Digital Assistants (PDAs) enabled with Internet,have emerged as the latest products that can connect to the Internet across a digital wireless network. Protocols, such as Wireless Application Protocol (WAP), and WML (Wireless Markup Language) have been developed for these devices to connect to the Internet.
Data is transfered in various way such as,through wireless local area networks (WLANs),Bluetooth.
Wireless Local Area Networks
WLANs are implemented within a building and can provide the final few meters of connectivity between a wired network and the mobile user.It is based on the IEEE 802.11 standard.It has three physical layer,two radio frequency specification and one infrared.Most WLANs operate in the 2.4 GHz license-free frequency band and have throughput rates up to 2 Mbps.The new 802.11astandardprovides throughput rates up to 54 Mbps.
WLAN configurations provides peer-to-peer connections between a set of PCs . It also provides point-to-point and point-to-multipoint wireless solutions. A point-to-point solution is used to bridge between two local area networks, and it is an alternative to cable between two geographically distant locations (up to 30 miles). Point-to-multi-point solutions connect several, separate locations to one single location or building.
Broadband wireless (BW) is an emerging wireless technology that allows simultaneous wireless delivery of voice, data, and video. BW is considered a competing technology with Digital Subscriber Line (DSL). BW comes in two ways: Local multi-point distribution service (LMDS) and Multi-channel multi-point distribution service (MMDS).
LMDS operates at high bandwidth of 28-31 GHz range of the frequency spectrum and has sufficient bandwidth to broadcast all the channels.
MMDS operates at lower frequencies, in the 2 GHz licensed frequency bands. MMDS has wider coverage than LMDS , but has lower throughput rates.
It is important to understand that in WLANs, data is encrypted only between the wireless adapter and the access point. Data travels through a wired LAN unencrypted. Therefore, data transmitted by wireless is not more secure than data transmitted through the wire, but probably not less secure.