Wi-Fi - ExplainedThe popular wireless networking technology known as Wi-Fi, is a way in which high-speed Internet and network connections are supplied using radio waves. The term Wi-Fi, which is a register trademark of the Wi-Fi Alliance, is specifically defined as any “wireless local area network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers’ (IEEE) 802.11 standards.” A common misconception is that the term Wi-Fi stands for “Wireless Fidelity”, however, this is not the case.

The Federal Communications Commission opened several bands of the wireless spectrum up to the consumer market in 1985. The three bands, 900Mhz, 2.4Ghz, and 5.8Ghz, were already allocated to other devices such as microwave ovens. In fact, many devices that operate on this spectrum, such as cordless landline phones and baby monitors, carry a warning that they may be affected by interference from microwaves.

The first major adopter of Wi-Fi was Apple. Apple told Lucent, a member of the Wi-Fi alliance (Then WECA), that if it could make an adapter for under $100, it would include Wi-Fi as an option on its new iBook. Apple used the name Airport, and other computer manufacturers soon followed in Apple’s footsteps. One such company was Cisco, which bought up LinkSys.

Wi-Fi, the technical specification, was developed by the 802.11 committee of the Institute of Electrical and Electronics Engineers between 1988 and 1997, as several companies in the WECA negotiated among themselves as to which standard would be adopted. After nearly a decade, the committee agreed to a specification which would allow for variations as legislation, speed and signal strength evolved. 802.11 had a speed of two megabits per second, and worked using spread spectrum. Spread spectrum means that that wireless transmissions are sent over a wide range of frequencies, and collected by the receiver. 802.11 is capable of both jumping between radio frequencies and spreading a signal over a wide band of frequencies.

The first two variations were 802.11b, which was ratified in December of 1999, and operates in the 2.4Ghz spectrum, and 802.11a, ratified in January 2000, which operates in the 5.8Ghz spectrum. 802.11b has a maximum speed of 11Mbit/s, and 802.11a has a maximum speed of 54Mbit/s. Many devices were “dual band,” meaning they could switch between 802.11a and 802.11b.

802.11a uses orthogonal frequency-division multiplexing (OFDM), which splits the signal into several smaller sub-signals and sends them over different frequencies at the same time. 802.11a is less subject to interference from other devices. 802.11b uses complementary code keying (CCK), which uses a set of 64 eight-bit code words, which have unique mathematical properties that allow a receiver to distinguish them from each other. The 802.11b standard is less susceptible to interference.

By June 2003, the third variation, 802.11g, came on the market, which, like 802.11b, works in the 2.4Ghz band, and had a speed of 54Mbit/s. The faster real-world performance and backwards compatibility of 802.11g made it successful. In October 2009, another improvement, 802.11n was developed and could operate in either the 5.8Ghz or 2.4Ghz spectrum, making it less susceptible to interference.

Wi-Fi and Wi-Fi-related standards continue to be developed by the IEEE. 802.11P is called Wireless Access in Vehicular Environments. With WAVE, vehicles will be able to communicate with each other and with infrastructure. In conjunction with transparent LCD, you will be able to have a heads-up display that will tell you things like if a car is coming from the other direction before you pass on a two way street, or warn you of hazardous road conditions. The 802.16 standard, also called WiMax, may be able to give wireless access to entire cities, making it competitive with 4G. Commercial airplanes use air-to-ground wireless data connections or satellite internet to create a hotspot for passengers to use.

Here are some very common types of devices that use Wi-Fi:

  • Tablets
  • Smartphones
  • PCs/Laptops
  • Video Game Consoles
  • Wireless VoIP Phones
  • Digital Audio Players/MP3

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