Signal transmission mechanism with diversity gain in satellite communication network

A satellite communication system for obtaining a diversity gain by transmitting a signal applied with a space and time block code (STBC) when a satellite communication network include repeaters having a simple amplifying function, comprising:

• a satellite for transmitting a first signal encoded to STBC using a band of a link formed between the satellite to a terminal and at a same time using a frequency band of a link formed between the satellite to each repeater and that differs from that a signal transmission frequency band of a link between a satellite and a repeater, respectively;
• at least one of first simple amplifying repeaters for receiving the first signal through the band of the link formed to the satellite, amplifying the received first signal, and transmitting the amplified first signal using a band of a link formed to a terminal;
• and
• at least one of second simple amplifying repeater for receiving the first signal through the band of the link formed to the satellite, transforming the first signal to a second signal having the same frequency band of the first signal, amplifying the transformed second signal, and transmitting the amplified second signal using a band of a link formed to a terminal allowing the terminal to regard the satellite and the repeater as two transmitting antennas transmitting signals encoded to STBC.

A satellite communication system for obtaining a diversity gain by transmitting a signal applied with a space and time block code (STBC) when a satellite communication network include repeaters having a frequency transforming function and a signal transmission band of a link between a satellite and a terminal differs from that of a link between the satellite and a repeater, comprising:

• the satellite for transmitting a first signal encoded to STBC using a band of a link between the satellite to the terminal and at a same time transmitting a second signal that is encoded to STBC using a frequency band of a link formed between the satellite to the repeater and that differs from that a signal transmission frequency band of a link between the satellite and the terminal;
• at least one of first frequency transforming repeaters for receiving the second signal through the band of the link to the satellite, transforming the received second signal to a second signal having a frequency band corresponding to the link between the satellite and a terminal, and transmitting the transformed second signal using a band of a link formed to the terminal;
• and
• at least one of second frequency transforming repeater for receiving the second signal through the band of the link formed to the satellite, transforming the received second signal to a first signal having a frequency band corresponding to a link between the satellite and the terminal, and transmitting the transformed first signal using a band of a link formed to the terminal allowing the terminal to regard the satellite and the repeater as two transmitting antennas transmitting signals encoded to STBC.

A method for detecting a signal in a terminal in a satellite communication system for obtaining a diversity gain by transmitting a signal applied with space time block code (STBC) from a satellite and a repeater to the terminal, the method comprising the steps of:

• estimating channel information corresponding to each received signal when receiving a signal encoded to STBC from the satellite and the repeater at the same time;
• generating a channel matrix using the estimated channel information;
• and
• detecting a transmitting signal by performing STBC decoding on the received signal based on STBC encoding information previously received from the satellite and the repeater and the generated channel matrix using a frequency band of a link formed between the satellite to the repeater and that differs from that a signal transmission frequency band of a link between the satellite and the terminal allowing the terminal to regard the satellite and the repeater as two transmitting antennas transmitting signals encoded to STBC.

A method for estimating a channel in a terminal in a satellite communication system for obtaining a diversity gain by transmitting a signal applied with space time block code (STBC) from a satellite and a repeater to the terminal, the method comprising the steps of:

• estimating channel information value by performing a predetermined channel estimation scheme on signals received from the satellite and the repeater at a same time;
• delaying the estimated channel information value as much as D′, applying to the delayed channel information value, and subtracting the result of applying the coefficient α from the estimated channel information value;
• and
• delaying the subtracted channel information value as much as D, applying to the delayed channel information value, and adding the result of applying the coefficient β to the subtracted channel information value using a frequency band of a link formed between the satellite to the repeater and that differs from that a signal transmission frequency band of a link between the satellite and the terminal allowing the terminal to regard the satellite and the repeater as two transmitting antennas transmitting signals encoded to STBC.