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.