Diversity gain in ultra wideband impulse radio (UWB-IR)

In this paper, we propose a Time Interleave (TI)-Ultra Wideband (UWB)-Impulse Radio (IR) system where N_f monocycle pulses per information symbol are transmitted not continuously but discontinuousiy through the time interleaver to get more time diversity. Moreover, we compare the diversity gains of the UWB-IR systems on block fading channels with the fading block size q: the UWB-IR system with a single transmit antenna, the Space Time (ST)-UWB-IR system with N_t transmit antennas, and the TI-UWB-IR system with a single transmit antenna. Simulation results show that when the fading block size q = 1, the diversity gains of all the systems are same. When q is larger than or equal to 2 (q ≥ 2) and when both the number of transmit antennas N_t of the ST-UWB-IR system and the time interleaver size N_TI of the TI-UWB-IR system are larger than or equal to q (N _t, N_TI ≥ q), we show the following; both the ST-UWB-IR system and the TI-UWB-IR system achieve the same diversity gain that is constant regardless of N_t and N_TI. On the other hand, when q ≥ 2 and when N_t and N_TI < q, we show the following; when N_t = N_TI, the ST-UWB-IR system and the TI-UWB-IR system get the same diversity gain; when N_t > N _TI, the diversity gain of the ST-UWB-IR system is larger than that of the TI-UWB-IR system; and vice when N_t > N_TI.