초록 ▼

A reduced cost, robust data communication scheme for very small aperture terminal satellite communication systems combines non-coherent frequency detection and trellis-coded, multi-frequency modulation. The data code width is associated with the size of a multiple frequency set and the selection of

A reduced cost, robust data communication scheme for very small aperture terminal satellite communication systems combines non-coherent frequency detection and trellis-coded, multi-frequency modulation. The data code width is associated with the size of a multiple frequency set and the selection of a given combination of frequencies for transmission during a respective baud. One portion the data is convolutionally encoded and points to an orthogonal signal set associated with frequencies of a partitioned multiple frequency set. Another portion of the data identifies the frequency combination within the group pointed to by the one portion. The combined portions encode a multi-frequency transmission waveform. At the receiver, the multi-frequency tone sequence is detected by non-coherent frequency detection. For each baud, matched filters output a most likely set of frequencies transmitted during that baud, as soft decisions to a Viterbi decoder.

대표청구항 ▼

[ What is claimed:] [1.] A method of communicating data over a communication link from a transmit site to a receive site comprising the steps of:(a) at said transmit site, trellis-encoding data to be transmitted into successive waveforms, each of which waveforms is comprised of a respective pluralit

[ What is claimed:] [1.] A method of communicating data over a communication link from a transmit site to a receive site comprising the steps of:(a) at said transmit site, trellis-encoding data to be transmitted into successive waveforms, each of which waveforms is comprised of a respective plurality of different simultaneously occurring frequencies in dependence upon respective digital code values of successive digital data words of said data, and transmitting said successive waveforms during successive bauds associated with successive digital data words of said data; and(b) at said receive site, detecting and trellis-decoding said successive waveforms to derive said data.