Space-time trellis coding for UWB-IR

Ultra wideband impulse radio (UWB-IR) has attractive features for high-speed multiple access with very low power. Space-time (ST) coding has gained much attention as an effective technique to increase channel capacity with multiple antennas. In particular, space-time trellis codes (STTC) generally can achieve better performance than space-time block codes (STBC). However, it has not been clarified how STTC be can applied to UWB-IR and how good the performance of the combination scheme is. We propose a space-time trellis coded UWB-IR (STTC-UWB-IR) system. To apply STTC to UWB-IR, the proposed system employs the biorthogonal modulation scheme that consists of pulse position modulation (PPM) with the polarity of the pulse. By computer simulation, we show that the proposed STTC-UWB-IR can achieve better error rate performance and accommodate more asynchronous users than a UWB-IR system with a single transmit antenna.