.

Thursday, July 9, 2015

Wi-Fi (Wireless Fidelity)

wireless-world

  Wi-Fi (Wireless Fidelity)

Wi-Fi (short for "wireless fidelity") is a term for certain types of wireless local area network (WLAN) that use specifications in the 802.11 family. The term Wi-Fi was created by an organization called the Wi-Fi Alliance, which oversees tests that certify product interoperability. A product that passes the alliance tests is given the label "Wi-Fi certified" (a registered trademark).
Originally, Wi-Fi certification was applicable only to products using the 802.11b standard.The 802.11 specifications are part of an evolving set of wireless network standards known as the 802.11 family. new versions of Wi-Fi called successively 802.11b, 802.11g, 802.11n, 802.11ac, and so on. Each of these related standards can communicate with each other, although newer versions offer better performance and more features.The particular specification under which a Wi-Fi network operates is called the "flavor" of the network. A basic Wi-Fi network with one wireless access point reaches at most only a few hundred feet (100m or less) in any direction. Expanding the range of a Wi-Fi network requires installing additional access points configured to communicate with each other, which becomes expensive and difficult to support, especially outdoors. As with other wireless protocols, signal interference (from other wireless devices, or from physical obstructions such as walls) can lower the effective range of Wi-Fi and its overall reliability.Wireless broadband routers commonly used in home networks serve (along with their other functions) as Wi-Fi access points. Similarly, public Wi-Fi hotspots utilize one or more access points installed inside the coverage area.
Small Wi-Fi radios and antennas are embedded inside smartphones, laptops, printers, and many consumer gadgets enabling them to function as network clients. Access points are configured with network names that clients can discover when scanning the area for available networks.

  
Bluetooth and Wi-Fi are to some extent complementary in their applications and usage. Wi-Fi is usually access point-centered, with an asymmetrical client-server connection with all traffic routed through the access point, while Bluetooth is usually symmetrical, between two Bluetooth devices. Bluetooth serves well in simple applications where two devices need to connect with minimal configuration like a button press, as in headsets and remote controls, while Wi-Fi suits better in applications where some degree of client configuration is possible and high speeds are required, especially for network access through an access node. However, Bluetooth access points do exist and ad-hoc connections are possible with Wi-Fi though not as simply as with Bluetooth

  wireless-world


                                    1.Bluetooth

                                     2.Wi-Fi (Wireless Fidelity)

                                      3.Infrared

                                       4.Wi-max, WLANS, WPANS, WMANS, WWMANS

                                        5.GSM

                                         6.3g

                                          7.4g

                                           8.GPRS

                                            9.CDMA

                                            10.EVDO

                                             11.UMTS and HSDP