Ultra Wideband

Ultra Wideband (UWB), is a modulation technique based on transmitting very-short-duration pulses, often of duration of only nanoseconds, whereby the occupied bandwidth goes to very large values. There are two major methods used to modulate waveforms: Time Modulated Pulse-position modulation and Bi-Phase Modulated Pulse-position modulation.

By long-established practice, UWB is considered to occupy a fractional bandwidth of 20% or greater, or a bandwidth of 250 MHz or more, of spectrum.

Processing gain, defined as the ratio of occupied bandwidth relative to the modulation bandwidth, is similar to spread spectrum for transmission. However, UWB is only typically able to benefit from processing gain during transmission. Reception of UWB is usually based on time-correlation of pulses, and the receiving benefits of processing gain possible with spread spectrum are not usually realized in practice.