How Wireless Internet Works Using Waves
Since 1999, Wi-Fi systems have been available to deliver broadband Internet access throughout a home or business without cables. Wi-Fi routers are an increasingly common consumer product. Several computers can share the same Internet connection as long as they are within range of the Wi-Fi router. Communication between computers and routers occurs by radio waves.
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Radio Waves
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You might visualize a radio wave as a tall bump. In fact, the wave starts half way up, rises to its maximum, falls to its minimum, then rises to the half-way mark. A true radio wave looks like a slanted "S." This configuration of signal runs from zero to maximum positive, down to maximum negative and back to zero. This is called a cycle, which is the industry term for a complete radio wave.
Frequencies
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Radio waves travel at different speeds. This speed is called a frequency. The more waves per second, the higher the frequency. Frequency is also the measure of the length of a cycle. The unit of measurement for radio waves is called a "hertz," which reports cycles per second. A kilohertz is 1,000 hertz; a megahertz is 1 million hertz; and a gigahertz is 1 billion hertz. The microwave range of radio frequency falls between 1 and 100 GHz. Wi-Fi networks run within this range. They use either 2.4 GHz or 5 GHz -- or both.
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Computer Data
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Computers cannot connect to networks unless they have a network adapter. Both wired and wireless network adapters have to convert the computer's parallel data to serial data. In computers bits (binary numbers) travel from one point to another along eight wires. All 8 bits of a byte leave and arrive together. Communications require bits in a line: bit 1 is followed by bit 2 and so on. So, computer data has to be made serial and then converted to an electronic pulse.
Network Wires
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Despite its name, wireless communication has wires. The antenna of a wireless adapter is a copper wire, the same as the wire inside a network cable. In network cable, that wire reaches to another device. In wireless systems, it is grounded at one end and hanging in thin air at the other end. In both cabled and wireless systems, the network adapter pulses data onto the wire as an electronic signal. When current passes along a wire, it creates a magnetic field around that wire, the pulse of the charge on the wire inside an antenna creates a pulsing magnetic field that radiates through the air.
Modulation
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A Wi-Fi transmitter sends out a regular pulse called a "carrier wave," a uniform wave marking frequency. The network adapter merges the data signal it receives from the computer with the carrier wave. This alters the shape of the carrier wave. This is called "modulation." Any receiver within range, which is another copper wire hanging in thin air, catches the magnetic wave and transmits the pulse to a network adapter. The network adapter subtracts the carrier wave frequency, leaving the data signal. This is then converted into parallel data and sent into the receiving computer.
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References
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