In telecommunications, spread spectrum is a technique where a signal's original bandwidth is spread across frequencies, widening its bandwidth. This process can result in increased security of communications, a resistance to interference and jamming, and an LPI (low probability of interception) by unintended recipients. It can also benefit satellite downlinks by limiting power flux density.
The idea of spread spectrum communications originated in 1900 when Nikola Tesla proposed a similar technique called frequency hopping. Commercial use of spread spectrum began in the 1980s, and the FCC allowed for unlicensed use of spread spectrum communications starting in 1985. These advances paved the way for modern wireless technologies, such as Wi-Fi, Bluetooth, and cell phones.