Method and system for satellite communication

• US 10,567,141 B2
• Filed: 07/03/2018
• Issued: 02/18/2020
• Est. Priority Date: 05/20/2014
• Status: Active Grant

• Current Assignee: SatixFy Israel Ltd.
• Original Assignee: SatixFy Israel Ltd.
• Inventors: Rainish, Doron
• Primary Examiner(s): Lam, Kenneth T
• Application Number:
  US16/026,399
• Publication Number:
  US 20180316479A1
• Time in Patent Office: 595 Days
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/1851 Systems using a satellite or space-based relay H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 43/18 Protocol analysers
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames

Abstract

The present invention provides communication technology (transmitter and receiver systems) for communicating data from the transmitter to one or more terminals'"'"' receivers over one or more communication channels. The communication channel is transmitted in burst communication mode such that transmission signal includes transmission data time slots at which one or more of said communication frames are encoded in the signal and one or more recess time slots between them. The communication receiver is adapted for processing signals of the burst mode communication channel and is operable for processing at least a portion of a signal received in the communication channel after a recess time period during which communication frames were not transmitted to determine a carrier frequency of the communication channel, based on a single communication frame appearing in the communication channel after the recess time period.

Claims

1. A communication receiver adapted for processing signals of a burst mode communication channel from a remote communication system, wherein the communication receiver is configured and operable for processing at least a portion of a signal received in said communication channel after a recess time period during which communication frames were not transmitted in said communication channel to determine a carrier frequency of said communication channel, based on a single communication frame appearing in the communication channel after said recess time period;

wherein the communication receiver comprises an input adapted to receive said signal and a signal time frame processor connectable to the input and configured and operable for continuous processing of time frame portions of the received signal to identity at least one code word of a group of one or more predetermined code words, being encoded in a time frame portion of the received signal;

said signal time frame processor comprising;

a. a carrier frequency analyzer configured and operable for analyzing said a time frame portion of the received signal in conjunction with said plurality of possible carrier frequencies simultaneously, by transforming said time frame portion to generate carrier-data including a plurality of carrier-data-pieces associated with each possible carrier frequency of said plurality of possible carrier frequencies respectively, whereby each of said carrier-data pieces being indicative of data encoded in said time frame portion over a carrier frequency associated with said carrier-data piece; and

b. a convolver configured and operable for processing the time frame portion of the signal to simultaneously identify whether said time frame portion encodes said at least one code word, over any one of said a plurality of possible carrier frequencies;

wherein said time frame processor is adapted to determine a time index of said code word in the received signal based on said time frame portion of the received signal at which said code word is identified; and

wherein said communication receiver further comprises an output adapted to output said time index.

2. The communication receiver of claim 1 configured and operable for identifying at least one code word in said communication frame and determine a time index at which said code word is encoded in the received signal and a carrier frequency over which said code word is encoded in the received signal.

3. The communication receiver of claim 1 wherein the input is adapted to receive said signal (e.g. EM signal) whereby said signal encodes communicated data over a certain unknown carrier frequency, being any one of a plurality of possible carrier frequencies residing within a predetermined frequency band.

4. The communication receiver of claim 1 wherein said signal encodes communicated data over a certain unknown carrier frequency, being any one of a plurality of possible carrier frequencies;

and said carrier frequency analyzer comprises a plurality of n signal mixers configured and operable for processing the received signal simultaneously whereby said plurality of signal mixers are adapted to apply a plurality of n respectively different predetermined frequency shifts to the received signals and thereby generate a plurality of at least n respectively different frequency shifted signals having their carrier frequencies shifted respectively by said different predetermined frequency shifts relative to said certain unknown carrier frequency of the received signal.

5. The communication receiver of claim 4 wherein said convolver comprises a plurality of at least n correlator modules connectable to said plurality of n signal mixers respectively and configured and operable for simultaneously convolving said plurality of frequency shifted signals respectively with said code word, to thereby generate a n convolved signal representations indicative of whether said code words is encoded in said frequency shifted signals respectively.

6. The communication receiver of claim 5 wherein said convolver comprises a plurality of at least nXm correlator modules, whereby m being an integer number greater than one;

and wherein each group of m correlator modules of said nXm correlator modules is connectable to a respective one signal mixer of said plurality of n signal mixers and is configured for simultaneously convolving a respective frequency shifted signal obtained by said respective one signal mixer with up to m code word simultaneously;

said convolver thereby generates up to nXm convolved signal representations indicative of whether any one of said m code words is encoded in any one of said n frequency shifted signals respectively.

7. The communication receiver of claim 6 comprising a code word identifier comprising a comparison module adapted for comparing at least one convolved signal representation of said n convolved signal representations with a predetermined criteria and thereby to determine whether said code word is encoded in the frequency shifted signal corresponding to said convolved signal representation.

8. The communication receiver of claim 1 wherein said convolver comprises a word convolver comprising:

a. a plurality of k^(l)=n delays configured and operable for applying k^(l) different time delays to the received signal and thereby generate k^(l) respective time delayed signals being copies of said received signal delayed by said k^(l) respective time delays; and

b. at least a first word convolution stage S^(l) comprising;

i. a code word provider adapted to provide k^(l) data portions indicative of n symbol constituents of said code word; and

ii. a plurality of k^(l) symbol convolvers;

whereby each symbol convolver of said plurality of k^(l) symbol convolvers is connectable to a respective delay of said plurality of delays, for receiving therefrom a corresponding time delayed signal, which is generated thereby, and is connectable to said code word providers for receiving corresponding symbol constituent of said k^(l) symbol constituents which location in said code words corresponds to the respective time delay of the time delayed signal of the respective delay, and configured and operable for convolving said time delayed signal with said corresponding symbol constituent to generate a respective symbol-convolved signal representations indicative of whether said symbol constituent is encoded in the corresponding time delayed signal;

said k^(l) symbol convolvers thereby generate k^(l) symbol-convolved signal representations indicative of whether said k^(l) symbol constituents of the code word are encoded in a timely order in said received signal.

9. The communication receiver of claim 8 wherein said carrier frequency analyzer comprises a time to frequency transformation module adapted for receiving said k^(l) symbol-convolved signal representations from said code word convolver and configured and operable for applying time to frequency transformation to said k^(l) symbol-convolved signal representations to obtain a frequency based representation of said n-symbol-convolved signal representations.

10. The communication receiver of claim 9 wherein said time to frequency transformation is a Fourier transform;

and wherein a peak in said frequency based representation satisfying a predetermined criteria (threshold) indicates said code word being encoded in the received signal;

a frequency index of said peak in said frequency based representation indicates a shift of the carrier frequency of said received signal; and

an intensity of said peak indicates significance level of said code word being encoded in the received signal.

11. The communication receiver of claim 8 wherein

said word convolver comprises a convolution stage cascade comprising said first convolution stage S^(l) and one or more cascaded additional convolution stages S^{(2) to (L)} each of the additional convolution stages S^(L) being configured and operable for receiving the k^(L-1) symbol-convolved signal representations from convolution stage S^(L-1) preceding and aggregating the symbol-convolved signal representations to generate a set having a lower number of k^(L)=k^(L-1)/N symbol-convolved signal representation pertaining to larger symbols of the code word;

and

the communication receiver further comprises a selector module configured and operable for selectively operating said time to frequency transformation module based on the symbol-convolved signal representations obtained from a selected stage of the set of convolution stages thereby enabling controllable adjustment of processing power requirements and accuracy of identification of said code word in the received signal.

12. A method of receiving signals comprising:

receiving signals transmitted in a burst mode communication channel from a remote communication system;

processing at least a portion of a signal received in said communication channel after a recess time period during which communication frames were not transmitted in said communication channel; and

determining a carrier frequency of said communication channel, based on a single communication frame appearing in the communication channel after said recess time period;

wherein said signal being received encodes communicated data over a certain unknown carrier frequency, being any one of a plurality of possible carrier frequencies residing within a predetermined frequency band; and

wherein the method comprises processing time frame portions of the received signal to identify at least one code word of a group of one or more predetermined code words, being encoded in a time frame portion of the received signal;

said processing of the time frame portions comprising;

a. analyzing a time frame portion of the received signal in conjunction with said plurality of possible carrier frequencies simultaneously; and

b. convolving the time frame portion of the signal with at least one code word to simultaneously identify whether said time frame portion encodes said at least one code word, over any one of said plurality of possible carrier frequencies;

c. determining a time index of said code word in the received signal based on said time frame portion of the received signal at which said code word is identified.

13. The method of claim 12 comprising identifying at least one code word in said communication frame and determine a time index at which said code word is encoded in the received signal and a carrier frequency over which said code word is encoded in the received signal.

14. The method of claim 12 wherein said analyzing comprises transforming said time frame portion to generate carrier-data including a plurality of carrier-data-pieces associated with each possible carrier frequency of said plurality of possible carrier frequencies respectively, whereby each of said carrier-data piece being indicative of data encoded in said time frame portion over a carrier frequency associated with said carrier-data piece;

said convolving is performed simultaneously for the plurality of carrier-data-pieces.

15. The method of claim 12 comprising operating a plurality of n signal mixers for simultaneously processing the received signal, by applying a plurality of n respectively different predetermined frequency shifts to the received signal and thereby generate a plurality of n respectively different frequency shifted signals having their carrier frequencies shifted respectively by said different predetermined frequency shifts relative to said certain unknown carrier frequency of the received signal.

16. The method of claim 15 wherein said convolving comprises operation a plurality of at least n correlator modules for simultaneously convolving said plurality of frequency shifted signals respectively with said code word, to thereby generate at least n convolved signal representations indicative of whether said code words is encoded in said frequency shifted signals respectively.

17. The method of claim 16 wherein said at least n correlator modules comprises at least nXm correlator modules, whereby each group of m correlator modules of said nXm correlator modules is configured for simultaneously convolving a respective frequency shifted signal obtained by said respective one signal mixer with up to m code word simultaneously;

thereby generating up to nXm convolved signal representations indicative of whether any one of said m code words is encoded in any one of said n frequency shifted signals respectively.

18. The method of claim 16 comprises comparing at least one convolved signal representation of said at least n convolved signal representations with a predetermined criteria and thereby to determine whether said code word is encoded in the frequency shifted signal corresponding to said convolved signal representation.