How it works? | Wi-Fi
Wi-Fi was built in 1998 in the laboratory of radio astronomy CSIRO in Australia. Creator of the wireless communication protocol is the engineer John O'Sullivan. The term "Wi-Fi" was originally coined as a play on words with "hint" on the Hi-Fi (High Fidelity - high precision). Despite the fact that in the beginning in some press releases figured the phrase "Wireless Fidelity" (or "Wireless Fidelity"), at the moment such a formulation is not used, and accordingly the term "Wi-Fi" in no way stands. How does wireless data transfer standard - Wi-Fi? This is in today's issue!
The operating principle of Wi-Fi based on the use of radio waves, and the exchange of data resembles talks on the radio. Typically, Wi-Fi-network circuit comprises at least one access point and at least one client. It is also possible to connect two clients when an access point is not used, and customers are connected by network adapters "directly." Adapters on each computer convert digital data into signals that are transmitted to other network devices. They convert incoming radio signals from the external network devices into digital data. Transmitters and receivers of one Wi-Fi-networks operate at the same frequency and use the same kind of data modulation in radio waves.
Wi-Fi-networks operate in specific bands of radio frequencies "2, 4" and "5" GHz, which are reserved in most countries under the so-called unlicensed radio services, ie those which can be used without obtaining a radio station license. To connect to the network must know the network ID. The access point transmits it using special signal packets at a speed 0, 1 Mbit / s every 100 milliseconds. Therefore, 0, 1 Mbit / s - the lowest data rate of Wi-Fi. Knowing the network ID, the customer can find out whether it is possible to connect to a given access point. After contact with the zone of the two access points with identical identifiers receiver can choose between them based on the signal strength data. Wi-Fi Standard gives the customer complete freedom in selecting the criteria for joining.
With an extensive coverage area router in the absence of obstacles - about 50-100 meters, the user can easily move around the room with your device without worrying about interrupting communications. In the memory of the router is stored routing table containing path to all devices connected to the access point. The width of the channel of Internet access provided by the ISP, is distributed uniformly among all the connected devices.
Wi-Fi standards are constantly improved. In January 2014 The standard has been adopted by the IEEE (Ai-and triple) 802.11ac, data rate using which can reach several gigabits / sec. There is also the IEEE 802.22 standard, designed for use in rural areas and capable of receiving data within a radius of 100 km at speeds up to 22 Mbit / s.