PPM-based Orthogonal Space-Time Coding for IR-UWB MIMO channels affected by Poisson-distributed Multipaths

In this contribution we develop a single multiple-input multiple-output impulse radio UWB (IR-UWB) transceiver for orthogonal (OPPM) data transmitted over (baseband) multipath faded MIMO channels. The proposed maximum-likelihood receiver results to be "partially coherent", because it is optimized to work without any information on the path gains, but only on the knowledge of the arrivals' times of the transmitted signals' replicas. The performance of the proposed transceiver are evaluated via three suitable versions of the Union-Chernoff bound related to several indoor and outdoor propagation scenarios, and through such limits we introduce a novel family of unitary orthogonal space-time block codes (e.g., the space-time OPPM (STOPPM) codes), that are able to attain the maximum of diversity and coding gains