Mobile Networks
This topic page is for organizing the development of content related to wireless systems.
If you are knowledgeable in any area Wireless systems, feel free to improve upon what you see, we would greatly appreciate your contributions.
Introduction
[edit | edit source]Wireless networks have significantly impacted the world as far back as World War II. With 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 only possible through wireless network systems using satellites and other signals to communicate across the world otherwise getting information 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, 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.
Wireless networking can entail a number of technologies. Some are listed below.
Infrared
[edit | edit source]Bluetooth
[edit | edit source]Typically used to create Personal Area Networks (PANs), Bluetooth has a distance limitation of up to 100 meters. The Bluetooth standard defines 3 classes of transmitters and receivers.
- Class 1 defines a maximum permitted power of 100mW (20 dBm) and can transmit up to approximately 100 meters.
- Class 2 defines a maximum permitted power of 2.5mW (4 dBm) and can transmit up to approximately 10 meters.
- Class 3 defines a maximum permitted power of 1mW (0 dBm) and can transmit up to approximately 1 meter.
IEEE 802.11
[edit | edit source]As described in Network communication medium, IEEE 802.11 refers to the standards of wireless technology most commonly used today in network connections.
The current standard for this the IEEE 802.11x standards also called Wi-Fi for Wireless Fidelity. Wi-Fi is being used by both business and consumer as a way to share a internet connection as well as P2P connections. Currently there are three Wi-Fi Standards a, b and g, the n and i standards are currently being developed.
802.11b - 802.11b was the first wi-fi standard to be introduced and has a maximum speed of 11Mbps.
802.11a - 802.11a was the second wi-fi standard and had a maximum speed of 54Mbps with the same range transmission and is not compatible with 802.11b because it used the 5GHz band and which has less interference.
802.11g - 802.11g was the third standard and had a maximum speed of 54Mbps and much farther range than both a and b but is backward compatible with 802.11b.
Security
[edit | edit source]- Wired Equivalent Privacy (WEP)
- Wi-Fi Protected Access (WPA)
- Wi-Fi Protected Access Version 2 (WPA2)
- 802.1x
Learning resources
[edit | edit source]A good beginning is ftp://ftp.3gpp.org Specs Year 2010 Dec for instance Chose Release 8 or above Pick up a maiden document such as 36.300 Subsequently as you delve deeper on a specific subject such as PHY layer, you might want to download specs 36.211,36.212.36.213 or 36.214
Wikipedia
[edit | edit source]External links
[edit | edit source]- Sinalgo - Wireless network simulator
- Generic 802.11 Networking Subsystem
- SWANS++
- NetSim - Useful network simulator for Research and Network lab experimentation
- Wireless Mesh Networks