Wi-fi

Wi-Fi or WiFi is a technology that allows electronic devices to connect to a wireless LAN (Local Area Network), mainly using the 2.4 gigahertz (12 cm) UHF and 5 gigahertz (6 cm) SHF ISM radio bands. 

A WLAN is usually password protected, but may be open, which allows any device within its range to access the resources of the WLAN network.

The Wi-Fi Alliance defines Wi-Fi as any "wireless local area network" (WLAN) product based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards. 

Logo for the Wi-Fi Alliance. image: wikipedia

 However, the term "Wi-Fi" is used in general English as a synonym for "WLAN" since most modern WLANs are based on these standards. "Wi-Fi" is a trademark of the Wi-Fi Alliance. The "Wi-Fi Certified" trademark can only be used by Wi-Fi products that successfully complete Wi-Fi Alliance interoperability certification testing.

A Netgear Wi-Fi Router. image: netgear

A common standard is 802.11n and it can transfer data from 54 Mbit/s to 600 Mbit/s

A little history of wifi

In 1971, ALOHAnet connected the Hawaiian Islands with a UHF wireless packet network. ALOHAnet and the ALOHA protocol were early forerunners to Ethernet, and later the IEEE 802.11 protocols, respectively.

A 1985 ruling by the U.S. Federal Communications Commission released the ISM band for unlicensed use. These frequency bands are the same ones used by equipment such as microwave ovens and are subject to interference.

In 1991, NCR Corporation with AT&T Corporation invented the precursor to 802.11, intended for use in cashier systems. The first wireless products were under the name WaveLAN.

The Australian radio-astronomer Dr John O'Sullivan with his colleagues Dr Terrence Percival AM, Mr Graham Daniels, Mr Diet Ostry, Mr John Deane  developed a key patent used in Wi-Fi as a by-product of a Commonwealth Scientific and Industrial Research Organisation (CSIRO) research project, "a failed experiment to detect exploding mini black holes the size of an atomic particle”.  In 1992 and 1996, CSIRO obtained patents for a method later used in Wi-Fi to "unsmear" the signal. 

The first version of the 802.11 protocol was released in 1997, and provided up to 2 Mbit/s link speeds. This was updated in 1999 with 802.11b to permit 11 Mbit/s link speeds, and this proved to be popular.

In 1999, the Wi-Fi Alliance formed as a trade association to hold the Wi-Fi trademark under which most products are sold


CSIRO Canberra connection to wifi development

Wi-Fi uses a large number of patents held by many different organizations.[9] In April 2009, 14 technology companies agreed to pay CSIRO $250 million for infringements on CSIRO patents.  This led to Australians labeling Wi-Fi as a Canberran invention, though this has been the subject of some controversy.  CSIRO won a further $220 million settlement for Wi-Fi patent-infringements in 2012 with global firms in the United States required to pay the CSIRO licensing rights estimated to be worth an additional $1 billion in royalties.


Celebrations:
World Wi-Fi day is 20th June , see also http://worldwifiday.com/


Adapted from: Wi-Fi. (2016, June 17). In Wikipedia, The Free Encyclopedia. Retrieved 07:25, June 20, 2016, from https://en.wikipedia.org/w/index.php?title=Wi-Fi&oldid=725767193