Wireless network refers to any type of computer network that is wireless, and is commonly associated with a telecommunications network whose interconnections between nodes is implemented without the use of wires.^[1] 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.^[2]

[edit] Types

[edit] Wireless PAN

Wireless Personal Area Networks (WPANs) interconnect devices within a relatively small area, generally within reach of a person. For example, Bluetooth provides a WPAN for interconnecting a headset to a laptop. ZigBee also supports WPAN applications.^[3]

[edit] Wireless LAN

Wireless Local Area Networks (WLANs) provide a Local Area Network (LAN) using radio instead of wires over a small area such as a home, office, or school. Most wireless LANs are based on the IEEE 802.11 standards.

Screenshots of Wi-Fi Network connections in Microsoft Windows. Figure 1, left, shows that not all networks are encrypted (locked unless you have the code, or key), which means anyone in range can access them. Figures 2 and 3, middle and right, however, show that many networks are encrypted.

• Wi-Fi: Wi-Fi is increasingly used as a synonym for 802.11 WLANs, although it is technically a certification of interoperability between 802.11 devices.
• Fixed Wireless Data: This implements point to point links between computers or networks at two locations, often using dedicated microwave or laser beams over line of sight paths. It is often used in cities to connect networks in two or more buildings without physically wiring the buildings together.

[edit] Wireless MAN

Wireless Metropolitan area networks are a type of wireless network that connects several Wireless LANs.

• WiMAX is the term used to refer to wireless MANs and is covered in IEEE 802.16d/802.16e.

[edit] Mobile devices networks

With the development of smart phones, cellular telephone networks routinely carry data in addition to telephone conversations:

• Global System for Mobile Communications (GSM): The GSM network is divided into three major systems: the switching system, the base station system, and the operation and support system. 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 to where it needs to go. GSM is the most common standard and is used for a majority of cell phones.^[4]
• Personal Communications Service (PCS): PCS is a radio band that can be used by mobile phones in North America and South Asia. Sprint happened to be the first service to set up a PCS.
• D-AMPS: Digital Advanced Mobile Phone Service, an upgraded version of AMPS, is being phased out due to advancement in technology. The newer GSM networks are replacing the older system.

See also mobile telecommunications.

[edit] Uses

An embedded RouterBoard 112 with U.FL-RSMA pigtail and R52 mini PCI Wi-Fi card widely used by wireless Internet service providers (WISPs) in the Czech Republic.

Wireless networks have had a significant impact on 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, efficiently and more reliably. Since then, wireless networks have continued to develop and their uses have grown significantly. Cellular phones are part of huge wireless network systems. People use these phones daily to communicate with one another. Sending information overseas 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.^[5]

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, as in most developing countries.

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 these issues. Wireless networks are typically slower than those that are directly connected through an Ethernet cable.

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.

[edit] Environmental concerns and health hazard

In recent times, there have been increased concerns about the safety of wireless communications, despite little evidence of health risks so far.^[6] The president of Lakehead University refused to agree to installation of a wireless network citing a California Public Utilities Commission study which said that the possible risk of tumors and other diseases due to exposure to electromagnetic fields (EMFs) needs to be further investigated.^[7]

[edit] See also

• Exposed terminal problem
• Physical layer
• Public Safety Network
• Wireless community network
• Wireless LAN
• Wireless access point
• Wireless LAN client comparison

[edit] References

[edit] Further reading

• Wireless Networking in the Developing World: A practical guide to planning and building low-cost telecommunications infrastructure (2nd ed.). Hacker Friendly LLC. 2007. pp. 425. http://wndw.net/pdf/wndw2-en/wndw2-ebook.pdf. 

[edit] External links

• Wireless at the Open Directory Project