Method of protection against errors in transmission of radiotelegraph messages and a device for the application of said method

Claim 1

A method of protection against errors in transmission of radiotelegraph messages utilizing an alternate two-way radiotelegraph link for establishing a communication between a transmitting station and a receiving station each provided with a receiver and a transmitter, wherein the method consists in having recourse both to error self-correction coding and to a repetition procedure for transmission of coded messages, said transmission being carried out in a synchronous manner and the following steps being involved: at the transmitting end, suppression of start bits and end bits of the usual telegraphic code; splitting of the messages into n-bit words; coding of n-bit words in the form of k-bit words, where (k-n) is equal to p bits and p corresponds to correction and detection coding; splitting of the message thus coded into blocks of N words consisting of k bits to which is added a z-bit control word, said N+1 word block being thus intended to constitute a field; transmission of the blocks thus formed after having performed interlacing of order N+1 and adding a bit and field synchronization sequence; at the receiving end, reception and decoding of each block emitted (by transmitting station) in the presence of the synchronization sequence; de-interlacing and correction of a maximum of one error per erroneous k-bit word and detection of words containing more than one error with formation of a repetition prase of N+1 bits, each bit being intended to correspond to each word of the received block; reading of the control word z transmitted with the k bit words storage of error-free words in memory at a predetermined address; transmission of a repetition request message interruption of the communication link.

Claim 2

A method of protection against errors in transmission of radiotelegraph messages utilizing an alternate two-way radiotelegraph link for establishing a communication between a transmitting station and a receiving station each provided with a receiver and a transmitter, wherein the method consists in having recourse both to error self-correction coding and to a repetition procedure for transmission of coded messages, said transmission being carried out in a synchronous manner and the following steps being involved: at the transmitting end, suppression of start bits and end bits of the usual telegraphic code; splitting of the messages into n-bit words; coding of n-bit words in the form of k-bit words, where (k-n) is equal to p bits and p corresponds to correction and detection coding; splitting of the message thus coded into blocks of N words consisting of k bits to which is added a z-bit control word, said N+1 word block being thus intended to constitute a field; transmission of the blocks thus formed after having performed interlacing of order N+1 and adding a bit and field synchronization sequence; at the receiving end, reception and decoding of each block emitted (by transmitting station) in the presence of the synchronization sequence; de-interlacing and correction of a maximum of one error per erroneous k-bit word and detection of words containing more than one error with formation of a repetition prase of N+1 bits, each bit being intended to correspond to each word of the received block; reading of the control word z transmitted with the k bit words storage of error-free words in memory at a predetermined address; transmission of a repetition request message interruption of the communication link.

Claim 6

A device for protection against errors in transmission of messages by radio in which an alternate two-way radiotelegraph link is established between a transmitting station and a receiving station each hsving a receiver and a transmitter, comprising bit synchronization means connected to the receiver for delivering an output signal and a clock signal, field synchronization means connected to the bit synchronization means for delivering a synchronization detection signal, a microprocessor having an interruption request input connected to the clock output of the bit synchronization means for performing the steps of. at the transmitting end, suppression of start bits and end bits of the usual telegraphic code; splitting of the messages into n-bit words; coding of n-bit words in the form of k-bit words, where (k-n) is equal to p bits and p corresponds to correction and detection coding; splitting of the message thus coded into blocks of N words consisting of k bits to which is added a z-bit control word, said N+1 word block being thus intended to constitute a field; transmission of the blocks thus formed after having performed interlacing of order N+1 and adding a bit and field synchronization sequence; C at the receiving end, reception and decoding of each block emitted (by the transmitting station) in the presence of the synchronization sequence; de-interlacing and correction of a maximum of one error pererroneous k-bit word and detection of words containing more than one error with formation of a repetition phrase of N+1 bits, each bit being intended to correspond to each word of the received block; reading of the control word z transmitted with the k-bit words; storage of error-free words in memory at a predetermined adresse; transmission of a repetition request message; interruption of the communication link; and array of peripheral equipment interfaces connected to the microprocessor via a bus line, storage means connected via said bus line to the microprocessor which is thus permitted to write and then to read the data managed by said microprocessor.

Claim 7

A device for protection against errors in transmission of messages by radio in which an alternate two-way radiotelegraph link is established between a transmitting station and a receiving station each hsving a receiver and a transmitter, comprising bit synchronization means connected to the receiver for delivering an output signal and a clock signal, field synchronization means connected to the bit synchronization means for delivering a synchronization detection signal, a microprocessor having an interruption request input connected to the clock output of the bit synchronization means for performing the steps of. at the transmitting end, suppression of start bits and end bits of the usual telegraphic code; splitting of the messages into n-bit words; coding of n-bit words in the form of k-bit words, where (k-n) is equal to p bits and p corresponds to correction and detection coding; splitting of the message thus coded into blocks of N words consisting of k bits to which is added a z-bit control word, said N+1 word block being thus intended to constitute a field; transmission of the blocks thus formed after having performed interlacing of order N+1 and adding a bit and field synchronization sequence; C at the receiving end, reception and decoding of each block emitted (by the transmitting station) in the presence of the synchronization sequence; de-interlacing and correction of a maximum of one error pererroneous k-bit word and detection of words containing more than one error with formation of a repetition phrase of N+1 bits, each bit being intended to correspond to each word of the received block; reading of the control word z transmitted with the k-bit words; storage of error-free words in memory at a predetermined adresse; transmission of a repetition request message; interruption of the communication link; and array of peripheral equipment interfaces connected to the microprocessor via a bus line, storage means connected via said bus line to the microprocessor which is thus permitted to write and then to read the data managed by said microprocessor.