Wireless_network

Wireless network
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Please improve this article if you can. (October 2006)


While the term wireless network may technically be used to refer to any type of network that is wireless, the term is most commonly used to refer to a telecommunications network whose interconnections between nodes is implemented without the use of wires, such as a computer network (which is a type of communications network). Wireless telecommunications networks are generally implemented with some type of remote information transmission system that uses electromagnetic waves, such as radio waves, for the carrier and this implementation usually takes place at the physical level or "layer" of the network. (For example, see the Physical Layer of the OSI Model).Contents [hide]
1 Types
2 Uses
3 Articles
4 Research institutes
5 Communities
6 Ideas
7 Environmental concerns and health hazard
8 See also
9 References
9.1 Annotated bibliography
10 External links


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Types
Wireless LAN
One type of wireless network is a WLAN or Wireless Local Area Network. Similar to other wireless devices, it uses radio instead of wires to transmit data back and forth between computers on the same network.
Screenshots of wireless LAN Networks. Figure 1, left, shows that not all networks are encrypted (locked unless you have the code), which means anyone can get onto them. Figures 2 and 3, middle and right, however, show that a lot of networks are encrypted.
Wi-Fi: Wi-Fi is a commonly used wireless network in computer systems which enable connection to the internet or other machines that have Wi-Fi functionalities. Wi-Fi networks broadcast radio waves that can be picked up by Wi-Fi receivers that are attached to different computers or mobile phones.
Fixed Wireless Data: Fixed wireless data is a type of wireless data network that can be used to connect two or more buildings together in order to extend or share the network bandwidth without physically wiring the buildings together.
Wireless MAN
A type of wireless network that connects several Wireless LANs.
WiMAX: WiMAX is the term used to refer to wireless MANs.
Mobile devices networks
Global System for Mobile Communications (GSM): The GSM network is divided into three major systems which are the switching system, the base station system, and the operation and support system (Global System for Mobile Communication (GSM)). The cell phone connects to the base system station which then connects to the operation and support station; it then connects to the switching station where the call is transferred where it needs to go (Global System for Mobile Communication (GSM)). This is used for cellular phones, is the most common standard and is used for a majority of cellular providers.
Personal Communications Service (PCS): PCS is a radio band that can be used by mobile phones in North America. Sprint happened to be the first service to set up a PCS.
D-AMPS: D-AMPS, which stands for Digital Advanced Mobile Phone Service, is an upgraded version of AMPS but it is being phased out due to advancement in technology. The newer GSM networks are replacing the older system.

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Uses

Wireless networks have significantly impacted the world as far back as World War II. Through the use of wireless networks, information could be sent overseas or behind enemy lines easily and quickly and was more reliable. Since then wireless networks have continued to develop and its uses have significantly grown. Cellular phones are part of huge wireless network systems. People use these phones daily to communicate with one another. Sending information over seas is possible through wireless network systems using satellites and other signals to communicate across the world. Emergency services such as the police department utilize wireless networks to communicate important information quickly. People and businesses use wireless networks to send and share data quickly whether it be in a small office building or across the world. Another important use for wireless networks is as an inexpensive and rapid way to be connected to the Internet in countries and regions where the telecom infrastructure is poor or there is a lack of resources, like most Developing Countries.

Wireless networks allow you to eliminate messy cables. Wireless connections offer more mobility, the downside is there can sometimes be interference that might block the radio signals from passing through. One way to avoid this is by putting the source of your wireless connection in a place where the signal will have as little interference as possible. Sometimes nearby networks are using the same frequencies, and this can also cause interference within the network and can reduce its performance.

Compatibility issues also arise when dealing with wireless networks. Different components not made by the same company may not work together, or might require extra work to fix compatibility issues. To avoid this, purchase products made by the same company so that there are fewer compatibility issues.

Wireless networks, in terms of internet connections, are typically slower than those that are directly connected through an Ethernet cable. Though the speed is slower, most things will still move at the same speed except for things like video downloads. Though wireless technology continues to develop, it is now easier to get networks up and running cheaper and faster than ever before.

A wireless network is more vulnerable because anyone can try to break into a network broadcasting a signal. Many networks offer WEP - Wired Equivalent Privacy - security systems which have been found to be vulnerable to intrusion. Though WEP does block some intruders, the security problems have caused some businesses to stick with wired networks until security can be improved. Another type of security for wireless networks is WPA - Wi-Fi Protected Access. WPA provides more security to wireless networks than a WEP security set up. The use of firewalls will help with security breaches which can help to fix security problems in some wireless networks that are more vulnerable.

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Articles
Wireless MAN - metropolitan area network
Wireless LAN - local area networks
Wireless PAN - personal area networks
GSM - Global standard for digital mobile communication, common in most countries except South Korea and Japan
PCS - Personal communication system - not a single standard, this covers both CDMA and GSM networks operating at 1900 MHz in North America
Mobitex - pager-based network in the USA and Canada, built by Ericsson, now used by PDAs such as the Palm VII and Research in Motion BlackBerry
GPRS - General Packet Radio Service, upgraded packet-based service within the GSM framework, gives higher data rates and always-on service
UMTS - Universal Mobile Telephone Service (3rd generation cell phone network), based on the W-CDMA radio access network
AX.25 - amateur packet radio
NMT - Nordic Mobile Telephony, analog system originally developed by PTTs in the Nordic countries
AMPS - Advanced Mobile Phone System introduced in the Americas in about 1984.
D-AMPS - Digital AMPS, also known as TDMA
Wi-Fi - Wireless Fidelity, widely used for Wireless LAN, and based on IEEE 802.11 standards.
Wimax - A solution for BWA (Broadband Wireless Access) and conforms to IEEE 802.16 standard.
Canopy - A wide-area broadband wireless solution from Motorola.

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Research institutes

The following institutions conduct wireless network related research:
National University San Diego, Califirnia [[1]]
Indian Institute of Science, Bangalore
G S Sanyal school of Telecommunications, IIT Kharagpur, India
University of California, Santa Barbara
University of California, Berkeley
İzmir Institute of Technology, Turkey
University of Pennsylvania
Massachusetts Institute of Technology
Helsinki University of Technology
Royal Institute of Technology (Stockholm, Sweden)
Stanford University
Iowa State University
Center for Wireless Information Network Studies, Worcester Polytechnic Institute
University of Southern California
University of Edinburgh Edinburgh, UK
Nanyang Technological University, Singapore
University of South Australia, Australia
University of Toronto, Canada
University of Alberta, Canada
Drexel University
University of Houston–Clear Lake

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Communities
Qualcomm [2]
SeattleWireless
NYCwireless
RedLibre
Personal Telco
Downtown Toronto

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Ideas
Warchalking

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Environmental concerns and health hazard

In recent time there are increased concerns and research linking usage of wireless communications with poor concentration, memory loss, nausea, premature senility and even cancer. Questions of safety have been raised, citing that long term exposure to electromagnetic radiation of the sort emitted by wireless networks may someday prove to be dangerous