Asynchronous space-time cooperative communications in sensor and robotic networks

For wireless sensor networks or robotic networks, cooperative communications encoded with space-time block code (STBC) are desirable to improve their energy efficiency and reliability. However, existing STBC-encoded cooperative communication schemes usually require perfect synchronization among the transmitting sensors or robots, which is difficult and even impossible to achieve in practice. In this paper, we address this problem by developing a new receiving scheme for Alamouti's STBC cooperative transmission where two asynchronous transmitting sensors or robots are employed. The new scheme uses a linear-prediction-based channel equalization technique to mitigate the effect of asynchronism. The performance of the new scheme is analyzed and demonstrated by simulations.