Data transmission process with auto-synchronized correcting code, auto-synchronized coder and decoder, corresponding transmitter and receiver

Abstract

A data transmission process with auto-synchronised correcting code, auto-synchronised coder and decoder, corresponding transmitter and receiver. According to the invention, synchronisation management signals (HS, SS, ID) are formed and, under the control of these signals, a header is inserted before a data group and after it a correcting code. At receive end, these synchronisation management signals are reconstituted, the presence of a header is detected and any erroneous symbols are corrected. The invention also provides for an auto-synchronised coder and a decoder and for a transmitter and a receiver using them.

1. A data transmission process with auto-synchronized correcting code, comprising:
 defining a timing of bits of the data, to be transmitted, by a clock signal and forming synchronization management signals comprising: 
 a symbol clock signal m number of times less fast than the clock signal, where m is an integer, and m bits constituting an information symbol,  
 a symbol synchronization signal capable of designating the first symbol of a packet, and  
 a data acquisition interruption signal intervening every K number of symbols, where K is a pre-set integer;  
 inserting a header before a first group of K symbols and inserting a second group of R symbols after said first group, the second group of R symbols comprising a correcting code corresponding to the K symbols of the first group, R being a pre-set integer dependent on a correcting code type used, the first and second groups of(R+K) symbols forming a packet, and the header being a header specific to this packet, under control of the data acquisition interrupting signal; and  
 modulating and transmitting each packet with its header;  
 demodulating the signal received and extracting the clock signal;  
 implementing a header search process in the demodulated signal and, when the header is detected, inhibiting the header search process and generating a symbol synchronization symbol;  
 processing the received packet so as to correct any erroneous symbols of the first group by the correcting code of the second group and reactivating the header search process after each packet processing, under the control of the symbol clock and symbol synchronization signals; and  
 retrieving, from the corrected symbols, the transmitted data.  
 
 
     
     
       2. The process according to  claim 1 , wherein:
 at transmission, said modulating is effected by spread spectrum by means of pseudo-random sequences; and  
 correlating with the pseudo-random sequences at transmission.  
 
     
     
       3. The process according to  claim 1 , wherein the correcting code is a Reed-Solomon type code. 
     
     
       4. An auto-synchronized coder, comprising:
 means for forming synchronization management signals, wherein the synchronization management signals comprise: 
 a symbol clock signal m times less fast as a clock signal timing the data bits, where m is an integer, and m bits constitute an information symbol,  
 a symbol synchronization signal locating the start of each symbol,  
 a data acquisition interruption signal intervening every K number of symbols, where K is a pre-set integer; and  
 
 means for inserting, under control of the acquisition interruption signal, a packet header before a first group of K symbols, and a second group of R symbols after said first group, the second group of R symbols constituting a correcting code assigned to the K symbols of the first group, R being a pre-set integer based at least in part upon the correcting code type used, the first and second group of (R+K) symbols forming a packet, and the header being a header specific to this packet.  
 
     
     
       5. A transmitter, comprising:
 a transmission module configured to modulate the data and to spread the spectrum of the data by a pseudo-random sequence; and  
 an auto-synchronized coda, before said transmission module, comprising: 
 means for forming synchronization management signals, the synchronization management signals comprising: 
 a symbol clock signal m times less fast than a clock signal timing the data bits, where m is an integer, m bits constituting an information symbol,  
 a symbol synchronization signal locating the start of each symbol, and  
 a data acquisition interruption signal intervening every K number of symbols, where K is a pre-set integer;  
 
 
 means for inserting, under control of the acquisition interruption signal, a packet header before a first group of K symbols and a second group of R symbols after said first group, the second group of R symbols constituting a correcting code assigned to the K symbols of the first group, R being a pre-sent integer dependent on the correcting code type used, the first and second group of(R+K) symbols forming a packet, and the header being a header specific to this packet.  
 
     
     
       6. A method of auto- synchronizing a correcting code for a data stream of information symbols, comprising:      inserting a packet header into the data stream before a group of K information symbols in the data stream, the packet header being associated with and being specific to the group of K information symbols:        inserting a group of R correction code symbols in the data stream after the group of K information symbols, the group of R correction code symbols comprising a correcting code for the group of K information symbols, and R comprising an integer value that is based at least in part on the correcting code;        transmitting the data stream containing the packet header and the correcting code; and,        generating a data acquisition interruption signal based at least in part on a timing of bits in an information symbol the data acquisition interruption signal indicating K number of information symbols,        wherein a symbol has m bits, and        wherein inserting a packet header into the data stream before a group of K information symbols in the data stream includes interrupting the data stream and inserting the packet header into the data stream based at least in part on the data acquisition interruption signal.     
     
     
       7. The method according to  claim 6  wherein transmitting the data stream including the correcting code further comprises:
   modulating the data stream including the correcting code based at least in part on a spread - spectrum modulation technique; and        transmitting the modulated data stream.     
     
     
       8. The method according to  claim 6  further comprising:
   receiving the data stream including the correcting code;        detecting a packet header in the received data stream including the correcting code; and        extracting from the received data stream the group of K information symbols associated with the detected packet header using the corresponding group of R correction code symbols to correct one or more symbols in the group of K symbols.     
     
     
       9. The method according to  claim 8 , wherein a symbol has m bits, the method further comprising generating a symbol clock signal and a symbol synchronization signal based at least in part on a timing of bits in an information symbol, the symbol clock signal including a frequency that is m times less than the timing of bits of an information symbol and the symbol synchronization signal capable of designating a first symbol of a group of K information symbols, and
   wherein extracting from the received data stream the group of K information symbols associated with the detected packet header is based at least in part on a timing provided by the symbol clock signal and the symbol synchronization signal.     
     
     
       10. The method according to  claim 8 , wherein the received data stream has been modulated based at least in part on a spread- spectrum modulation technique, and      wherein receiving the data stream includes the correcting code further comprises demodulating the modulated received data stream.     
     
     
       11. The method according to  claim 8 , wherein the correcting code comprises a Reed- Solomon - based correcting code.   
     
     
       12. The method according to  claim 6 , wherein the correcting code comprises a Reed- Solomon - based correcting code.   
     
     
       13. A coder, comprising:
   a synchronization signal generator adapted to generate a data acquisition interruption signal indicating K number of information symbols of a data stream including information symbols; and        a packet - header inserter adapted to insert a packet header into the data stream before a group of K information symbols based at least in part on the data acquisition interruption signal, the packet header being specific to the group of K information symbols, the inserter further inserting into the data stream a group of R correcting - code symbols after the group of K information symbols, the group of R correcting - code symbols being associated with the group of K information symbols, R comprising an integer based at least in part upon a correcting - code type of the correcting - code symbols, the packet header, the group of K information symbols and the group of R correcting - code symbols forming a packet.     
     
     
       14. A coder according to  claim 13 , wherein the correcting code symbols comprise a Reed- Solomon - based correcting code.   
     
     
       15. The coder according to  claim 13 , further comprising:
   a modulator adapted to modulate the data stream including the correcting code symbols based at least in part on a spread - spectrum modulation technique; and        a transmitter adapted to transmit the modulated data stream.     
     
     
       16. A coder, comprising:
   means for generating a data acquisition interruption signal indicating K number of information symbols of a data stream including information symbols; and        packet - header inserter means for inserting a packet header into the data stream before a group of K information symbols based at least in part on the data acquisition interruption signal the packet header being specific to the group of K information symbols the packet - header inserter means further adapted to insert into the data stream a group of R correcting code symbols after the group of K information symbols the group of R correcting code symbols being associated with the group of K information symbols R comprising an integer based at least in part upon a correcting - code type of the correcting - code symbols the packet header, the group of K information symbols and the group of R correcting - code symbols forming a packet.     
     
     
       17. A coder according to  claim 16 , wherein the correcting code symbols comprise a Reed- Solomon - based correcting code.   
     
     
       18. The coder according to  claim 16 , further comprising:
   modulator means for modulating the data stream including the correcting code symbols based at least in part on a spread - spectrum modulation technique; and        transmitter means for transmitting the modulated data stream.     
     
     
       19. A transmitter, comprising:
   a coder adapted to form a data stream including a correcting - code, the coder comprising:      a synchronization signal generator adapted to generate a data acquisition interruption signal indicating K number of information symbols of a data stream including information symbols, and        a packet - header inserter adapted to insert a packet header into the data stream before a group of K information symbols based at least in part on the data acquisition interruption signal, the packet header being specific to the group of K information symbols, the inserter further inserting into the data stream a group of R correcting - code symbols after the  - group of K information symbols, the group of R correcting - code symbols being associated with the group of K information symbols, R comprising an integer based at least in part upon a correcting - code type of the correcting - code symbols, the packet header, the group of K information symbols and the group of R correcting - code symbols forming a packet; and        a transmission module adapted to modulate the data stream including a correcting - code using a spread - spectrum modulation technique.       
     
     
       20. A transmitter according to  claim 19 , wherein the correcting code comprises a Reed- Solomon - based correcting code.   
     
     
       21. A transmitter according to  claim 19 , wherein the transmission module is further adapted to transmit the modulated data stream.