초록 ▼

The present invention relates to a technique for increasing the rain margin at ground stations of a satellite communication system. In the present technique, spare TDMA time slots in each frame sequence are shared among all ground stations as required by stations experiencing a fade condition which

The present invention relates to a technique for increasing the rain margin at ground stations of a satellite communication system. In the present technique, spare TDMA time slots in each frame sequence are shared among all ground stations as required by stations experiencing a fade condition which exceed a predetermined power margin. Additional up-link power margin at a faded transmitter can be achieved by either increasing power transmission of a normal burst or by the use of spare time slots plus encoding and preamble field extension techniques for burst extension. Additional down-link power margin to a faded receiver is accomplished by either increased transmitter power transmission or by the use of burst extension and coding and field extension techniques. Apparatus for implementing framing, carrier and clock recovery and start of message detection using extended fields and coding techniques for other data at a transmitter and receiver and disclosed to overcome fade conditions.

대표청구항 ▼

In a TDMA satellite communication system comprising a satellite and a plurality of remote, spaced-apart, ground stations which communicate with one another via the satellite using message bursts in assigned time slots of a frame sequence, a transmitter capable of launching one or more message bursts

In a TDMA satellite communication system comprising a satellite and a plurality of remote, spaced-apart, ground stations which communicate with one another via the satellite using message bursts in assigned time slots of a frame sequence, a transmitter capable of launching one or more message bursts during the frame sequence to each destination ground station where each message burst includes preamble and data information, the transmitter comprising: an input capable of receiving the data information and a certain portion of the preamble information associated with each message burst to be transmitted to each destination ground station; first means (32) capable of generating the remaining portion of the preamble information associated with each message burst to be transmitted; and means (36) capable of appropriately multiplexing the information both received at the input and generated by the first means for generating the remaining portion of the preamble information to form each message burst for transmission to a destination ground station CHARACTERIZED IN THAT the transmitter further comprises: control means (27) capable of generating a first control signal in response to a nonfade condition existing in transmissions between the transmitter and the destination ground station of a message burst to be transmitted, and a second control signal in response to a detected fade condition occurring in transmissions between the transmitter and a destination ground station of a message burst to be transmitted; an encoder (24) capable of encoding an input digital signal into a redundancy encoded output signal; second means (30) capable of generating the remaining portion of the preamble information which is an extended version of the remaining portion of the preamble information generated by the first means; and switching means (25, 38) capable of coupling both the input to the transmitter and said first means to the multiplexing means in response to a first control signal from said control means and capable of coupling both said encoder into the path between the input to the transmitter and the multiplexing means, and said second means to the multiplexing means in response to a second control signal from the control means for forming a message burst at the output of the multiplexing means.