All RF communication links are subject to multipath distortions caused by the radio signal reflecting off of one or more objects, such as walls, floors, desks, etc. The receiver sees the sum of all these signals. Since the time of flight for any reflection can be different due to the change in length of the signal path, the receiver can see phase shifts in the received signal. These phase shifts can be exaggerated by the relative movement of the receiver and transmitter to one another, as well as the movement of any object reflecting the signal. Multipath effects make it harder for narrowband receivers that rely on modulated carriers to accurately decode the received signal, potentially causing communication breakdowns as a user moves around a given space.

LE-UWB uses impulses to send data. The receiver looks for the presence or absence of RF energy in a given band within a particular time slot.  This gives LE-UWB significant multipath fading rejection as the multipath signals added together at the receiver boost the amount of total energy received.  In addition, since determining phase is not fundamental to decoding data, the phase changes caused by time-of-flight differences of each multipath do not interfere with the ability to correctly decode the signal.

Because UWB transmits data using pulses, the phase shift of the received signal caused by multi-path effects does not interfere with the receiver’s ability to decode the signal. In addition, the relative movement of the receiver, transmitter, and objects reflecting signals does not matter.