Beidou short message communication method and system for low-power user terminal

A Beidou short message communication method for a low-power user terminal, wherein the method comprises:

• by a user terminal, receiving outbound signals broadcast by a central station and forwarded by a satellite transponder, determining a response beam according to the outbound signals, carrying out Doppler frequency compensation, and constructing a short message access frame with a fixed length for transmission;
• wherein the short message access frame comprises a synchronous head and a user mark;
• by the central station, receiving and parsing the short message access frame, obtaining user characteristic information, time information and spatial distance between the user terminal and the central station, carrying out a time-frequency resource block allocation according to the user characteristic information, the time information and the spatial distance, and transmitting time-frequency resource blocks to the user terminal;
• by the user terminal, transmitting a short message communication frame with a fixed format to the central station according to the time-frequency resource blocks;
• wherein the short message communication frame comprises the synchronous head and a data segment;
• and
• by a communication receiving device of the central station, receiving and sequentially carrying out sampling preprocessing, anti-interference processing, rapid capture and tracking demodulation on the short message communication frame to obtain communication service information, and pushing receipt information to the user terminal to complete an information push.