Asynchrony Resilient Space-Time Block Codes

We present and evaluate methods for space-time coding over non-colocated transmit antennas. The proposed designs generate space-time block codes (STBCs) via systematic transformations of existing orthogonal STBCs. With a controlled reduction in rate in the form of a circular prefix, the resulting codes allow the maximum space diversity to be harvested in the presence of asynchrony in the transmissions. Subject to a maximum allowable relative delay in the signals received from distinct transmit antennas and assuming baud-rate sampling and circular-prefix removal at the receiver, the resulting received signal can be equivalently modeled as arising from synchronous STBC transmission with orthogonal or diagonal STBCs, implying that these designs provide full space diversity with low-complexity decoding in asynchronous settings.