Design and Analysis of Asynchronous Space-Time Codes over Multiple Base Stations Coordinating Downlink Systems

Via transformations of existing orthogonal space-time block codes (STBC) for synchronous multiple input-multiple output (MIMO) wireless communication systems with collocated transmit antennas, the proposed encoding method and decoding algorithm can generate asynchronous orthogonal or diagonal STBC applied in coordinated multiple base stations downlink transmission systems. This method requires channel information state (CSI) only at the receiver. With a cost of code rate and coding gains in form of a circular prefix, the resulting codes allow to provide full space diversity with low-complexity decoding in asynchronous settings. Finally, system performance and the ability to process asynchronous reception of signals element from different geographically separated transmit antennas are analyzed.