Wireless communication

Wireless communication
Wireless communication is the transfer of information over a distance without
the use of electrical conductors or "wires". Wireless technology include GPS units, garage door peners and or garage doors, wireless computer mice, keyboards and headsets, atellite television and cordless telephones.

Wireless networking
Wireless networking (i.e. the various types of unlicensed 2.4 GHz WiFi devices)
is used to meet many needs. Perhaps the most common use is to connect laptop
users who travel from location to location. Another common use is for mobile
networks that connect via satellite. A wireless transmission method is a logical
choice to network a LAN segment that must frequently change locations.

Wireless LAN
The notebook is connected to the wireless access point using a PC card wireless card.
A diagram showing a Wi-Fi networkA wireless local area network (WLAN) links two or more devices using some wireless istribution method, and usually providing a connection through an access point to the wider internet. This gives

users the mobility to move around within a local coverage area and still be connected to the network.

Types of wireless LANs

Peer-to-peer
Peer-to-Peer or ad-hoc wireless LANAn ad-hoc network is a network where stations communicate only peer to peer(P2P). There is no base and no one gives permission to talk. This is accomplished using the Independent Basic

Service Set (IBSS).
A peer-to-peer (P2P) network allows wireless devices to directly communicate with each other. Wireless devices within range of each other can discover and communicate directly without involving central access points. This method is typically used by two computers so that they can connect to each other to form a network.

Bridge
A bridge can be used to connect networks, typically of different types. A wireless Ethernet bridge allows the connection of devices on a wired Ethernet network to a wireless network. The bridge acts as the connection point to the Wireless LAN.

Wireless distribution system
A Wireless Distribution System is a system that enables the wireless interconnection of access points in an IEEE 802.11 network. It allows a wireless network to be expanded using multiple access points without the need for a wired backbone to link them, as is traditionally required. The notable advantage of WDS over other solutions is that it preserves the MAC addresses of client packets across links between access points.

WLAN standards
Several standards for WLAN hardware exist:

802.11a, b, and g
The 802.11a, b, and g standards are the most common for home wireless access points and large business wireless systems. The differences are:

•802.11a: With data transfer rates up to 54Mbps, it is faster than 802.11b and can support more simultaneous connections. Because it operates in a more regulated frequency, it gets less signal interference from other devices and is considered to be better at maintaining connections. In areas with major radio interference (e.g., airports, business call centers), 802.11a will outperform 802.11b. It has the shortest range of the three standards (generally around 60 to 100 feet), broadcasts in the 5GHz frequency, and is less able to penetrate physical barriers, such as walls.

•802.11b: It supports data transfer speeds up to 11Mbps. It's better than 802.11a at penetrating physical barriers, but doesn't support as many simultaneous connections. It has better range than 802.11a (up to 300 feet in ideal circumstances; tests by independent reviewers commonly achieve between 70 and 150 feet), and uses hardware that tends to be less expensive. It's more susceptible to interference, because it operates on the same frequency (2.4GHz) as many cordless phones and other appliances. Therefore, it's not considered a good technology for applications that require absolutely reliable connections, such as live video streaming.

•802.11g: It's faster than 802.11b, supporting data transfer rates up to 54Mbps. It has a slightly shorter range than 802.11b, but still better than 802.11a. Most independent reviews report around 65 to 120 feet in real-world situations. It is backward-compatible with 802.11b products, but will run only at 802.11b speeds when operating with them. It uses the 2.4GHz frequency, so it has the same problems with interference as 802.11b.

802.11n
The Institute of Electrical and Electronics Engineers (IEEE) has not yet ratified the 802.11.n standard. Because of this, some manufacturers advertise their 802.11n equipment as "draft" devices.

Though specifications may change once the standard is finalized, it is expected to allow data transfer rates up to 600Mbps. Product manufacturers are advertising ranges twice as large as those of as 802.11b/g devices, but as with any wireless devices, range ultimately depends more on the manufacturer and the environment than the standard.