A 2x2 Shape-Preserving ST Code for UWB Communications with Multipulse PPM

In this paper, we consider the application of Multipulse Pulse Position Modulation (MPPM) as a power-efficient modulation scheme for Impulse-Radio Ultra-Wideband (IR-UWB) communications and we propose the first known MPPM-specific 2×2 space-time code that is convenient for this modulation. The proposed rate-1 code achieves a full transmit diversity order with all MPPM constellations without introducing any constellation expansion. We also show that the proposed code profits from a low decoding complexity in the absence of interference between the different modulated UWB pulses.