Communication method and apparatus for providing an enhanced signal from diverse signals

• US 4,074,230 A
• Filed: 05/24/1976
• Issued: 02/14/1978
• Est. Priority Date: 05/24/1976
• Status: Expired due to Term

• Current Assignee: Teledyne Industries Incorporated (Teledyne Technologies Incorporated)
• Original Assignee: Teledyne Industries Incorporated (Teledyne Technologies Incorporated)
• Inventors: Icenbice, Phineas J. Jr.
• Primary Examiner(s): Atkinson, Charles E.
• Application Number:
  US05/689,331
• Time in Patent Office: 631 Days
• Field of Search: 340/146.1 BE, 340/146.1 R, 325/41, 325/56
• US Class Current: 714/777
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/06 using space diversity

Abstract

A communication method and apparatus for providing an enhanced signal from diverse signals whereby high accuracy communication may be established between remote points, even in the presence of severe signal fading and drop outs. The information to be transmitted is provided in digital form and formatted so as to have a Barker code or sync code of adequate length to achieve the desired false alarm rate filtering, followed by the data broken up into data blocks each containing an error detection and correction code for the respective block so that accurate microsecond processing of the signals is possible. The digital signals are modulated and transmitted, ideally with a plurality of frequencies, and are received, preferably at a plurality of remote satellite receiving sites with a plurality of space, path and polarization diversity techniques. The received signals are then processed and a data output signal is constructed from the multiple signals by utilizing the data blocks for which the sync code was properly received and for which the respective error detection and correction code indicates is true data.

Claims

1. A method of communicating comprising the steps of:

(a) providing a digital signal to be communicated;

(b) formating the digital signal into a serial digital signal having a plurality of information bits, the digital signal being preceded by a predetermined recognition code, and containing an error detection code, the error detection code having a number of bits which is less than the number of information bits;

(c) modulating and transmitting the digital signal;

(d) receiving and demodulating a plurality of diverse signals each representing the transmitted signal, to provide a plurality of received digital signals;

(e) interrogating the plurality of received digital signals for recognition of the predetermined recognition code;

(f) interrogating the plurality of received information bits in the digital signals in conjunction with their error detection code; and

(g) assembling a digital signal by selecting at least one received digital signal for which the recognition code was in fact recognized and which the respective error detection code indicates is accurate.

2. The method of claim 1 wherein step (b) comprises the step of formating the digital signal into a serial digital signal preceded by a predetermined recognition code, and containing a plurality of data blocks, each containing a plurality of information bits and an error detection code;

and step (g) comprises the step of assemblying a digital signal by selecting data blocks from the received digital signals for which the recognition code was in fact recognized and for which the respective data block was indicated as true by the associated error detection code.

3. The method of claim 2 wherein the error detection code comprises a Hamming code for single error detection and correction and double error detection.

4. The method of claim 3 wherein single errors detected in step (f) of claim 1 are corrected.

5. The method of claim 1 wherein step (c) comprises the step of modulating and transmitting the digital signal on at least two carrier frequencies.

6. The method of claim 1 wherein step (d) comprises the step of receiving the signals at a plurality of remote receiving stations.

7. The method of claim 1 wherein the diverse signals received are signals having a plurality of diversities.

8. A method of communicating comprising the steps of:

(a) providing a digital signal to be communicated;

(b) formating the digital signal into a serial digital signal having a plurality of data blocks preceded by a predetermined recognition code, each of the data blocks having a plurality of information bits and an error detection code, the error detection code having a number of bits which is less than the number of information bits;

(c) modulating and transmitting the formated digital signal at a plurality of frequencies;

(d) receiving the frequency diverse signals at a plurality of remote satellite receiving stations;

(e) demodulating each of the frequency diverse signals received at each of the plurality of remote satellite receiving stations to provide a plurality of received digital signals;

(f) interrogating the plurality of received digital signals for recognition of the predetermined recognition code;

(g) interrogating at least some of the data blocks of the plurality of received digital signals in conjunction with their error detection code; and

(h) assembling a digital signal by selecting data blocks from the received digital signals for which the recognition code was in fact recognized and for which the respective data block was indicated as being accurate by the associated error detection code.

9. The method of claim 8 wherein the error detection code comprises a Hamming code for single error detection and correction and for double error detection.

10. The method of claim 9 wherein single errors detected in data blocks of the received digital signals are corrected.

11. Communication apparatus comprising:

transmitting means for transmitting a signal containing digital information having a recognition code and at least one data block having a plurality of information bits and a lesser plurality of error detection code bits;

receiving means for receiving diverse signals each representing said transmitted signal;

comparing means coupled to said receiving means for comparing said recognition code of said received signals with a predetermined recognition code;

interrogating means coupled to said receiving means for interrogating data blocks in light of their error detection code; and

means coupled to said comparing means and said interrogating means for providing an output representing a data block from at least one of said diverse signals for which the recognition code was recognized and for which the respective error detection code failed to indicate an error.

12. The apparatus of claim 11 wherein said transmitting means comprises means for transmitting a recognition code and a plurality of data blocks associated therewith, said interrogating means is a means for interrogating successive data blocks, each in light of its error detection code, and said means for providing an output is a means for providing an output comprised of successive data blocks, each data block representing a data block from at least one of said diverse signals for which the recognition code was recognized and for which the respective error detection code failed to indicate an error.

13. The apparatus of claim 11 wherein said receiving means comprises a plurality of means for receiving diverse signals, each spaced from the others and being distributed about an area.

14. The apparatus of claim 11 wherein said transmitting means comprises a means for transmitting a signal at a plurality of frequencies, each representing said signal, and said means for receiving diverse signals comprises means for receiving signals at said plurality of frequencies.

15. The apparatus of claim 14 wherein said means for receiving diverse signals comprises a plurality of means for receiving diverse signals, each spaced from the others and being distributed about an area.