Space-Time Diversity Schemes with Blind Channel Estimation for TH-PPM UWB MIMO Communications

—For a time-hopping (TH) pulse position modulation (PPM) based ultra-wideband (UWB) multiantenna system, we propose four coherent space-time (ST) diversity schemes, corresponding to which the correlation template signals with blind channel estimation are also presented. First of all, the issue of channel identifiability based on first-order statistics is addressed, aspired by the singleantenna case [1]. Then, we shed light on that the determination of space-time structure is related to both channel estimation and signal detection. After that, four ST diversity structures are presented to guarantee both the feasibility of blind channel estimation and no multi-antenna interference introduced into signal detection. Finally, substantial simulations show that the proposed ST diversity schemes can significantly outperform the traditional single-antenna system especially for high signal-tonoise ratios whether channel state information is perfect or not.