Tradeoff of Transmitted Power in Time-Reversed Impulse Radio Ultrawideband Communications

In this letter, the tradeoff of transmitted power in time-reversed impulse radio ultrawideband (UWB) communications is investigated to make sure that the system works under the Federal Communications Commission´s (FCC´s) emission mask and, at the same time, keeps its enhanced performance. The energy spectral density of time-reversed pulses is discussed, and then an approximate value of 0.79 for the so-called compensation coefficient is obtained using the Monte Carlo simulation. In addition, an evaluation of the time-reversed transmission under an indoor office environment is carried out based on the finite-difference time-domain (FDTD) method. It is verified that the time-reversed UWB communication remains the improvement compared to the conventional ones, though the tradeoff demands lower transmit power.