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 antenna. 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 we can apply STTC to UWB-IR and how good the performance of the combination scheme is. In this paper, 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. From the 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.