Wi-Fi Data Transfer Speed

Wi-Fi is the colloquial name for the popular 802.11 wireless data networking protocol which supports PCs, smartphones, printers and many other devices. In addition to providing Internet access without the hassle of traditional cabling, Wi-Fi data transfers operate at relatively high speeds under optimal conditions. However, distance can reduce a Wi-Fi router's signal strength, compromising data speed.

Wi-Fi sends data bits over the air as radio waves, essentially taking the place of the cables used in earlier Ethernet technology. Each device and network router has low-power radio transmitters and receivers. The earliest version of Wi-Fi, 802.11, operates at a frequency of 5.2 GHz; equipment using the more recent 802.11n uses 2.4 GHz -- the same commercial frequency range used by cordless phones, baby monitors and other wireless equipment. Wi-Fi avoids conflicts with other devices by automatically switching among multiple channels; this lets you have several different wireless systems in the same office or household.

The speed at which Wi-Fi sends data depends on the particular 802.11 standard to which the equipment was built, among other factors. After its introduction in 1997, Wi-Fi continued to evolve, allowing technology advances to improve performance. Each 802.11 implementation automatically adjusts the data rate to allow computers to work under a variety of conditions. The earliest 802.11 standard, for example, allows rates of 1 to 2 megabits per second. With multiple antennas, Wi-Fi equipment with the 802.11ac standard can achieve speeds up to gigabits per second.

Radio signals grow weaker as the distance between the transmitter and receiver increases; the maximum distance for Wi-Fi depends on the standard, with 802.11a allowing 95 feet and 802.11n topping out at 230 feet. Outside this range, Wi-Fi may not work at all. The use of data networks in large buildings requires multiple wireless access points set up with overlapping areas of coverage.

Walls, furniture, equipment and other obstacles block and scatter radio signals, compromising the speed of wireless networks. Non-metallic objects tend to absorb radio energy, reducing signal strength. Metal ductwork, desks, appliances and other objects reflect radio waves, creating “dead spots” in certain areas. Because typical homes and businesses are loaded with such obstacles, real-world Wi-Fi data transfer rates are typically a fraction of the maximum possible speed; changing the location of computers, peripherals and obstacles can significantly improve network communications.