Achieving full transmit diversity for PPM constellations with any number of antennas via double position and symbol permutations

We present a general technique for constructing minimal-delay rate-1 Space-Time (ST) block codes for Pulse Position Modulations (PPM) with an arbitrary number of transmit antennas. We show that the novel idea of time-domain constellation extension as well as introducing joint position and symbol permutations achieves a full transmit diversity order while maintaining unipolar transmissions. This renders the proposed scheme suitable for low-cost Time-Hopping Ultra- Wideband (TH-UWB) systems as well as Free-Space Optical (FSO) communications with direct detection.