The method of discrete information transmission

 

The invention relates to the field of radiocommunications, telecommunications and computing, and more particularly to methods and devices for data transmission in computer networks. The invention consists in the conversion of the input message signal at the transmitting end of a communication line into a sequence of code combinations consisting of n information bits, are added to each code combination of information bits k - control bit, the combination of which is determined depending on the combination of n information bits, and on the receiving end of the communication line restoring messages from received code combinations and applying it to the target device, and the transmitting end of a communication line combination of k control bits are selected in accordance with the symbolidetermined by summing modulo P=2kicorresponding to the combination of k - selected information bit symboli-1appropriate combinations of k - control bit of the previous code messagesi=i-1+*ifor the selected combination of k information bits by adding modulo P=2kicorresponding to the received combination of the control bits, with the dual symbolci-1corresponding to the combination of the control bits of the previous code messages*i=i+ci-1(mod P), whereci-1=P-i-1compare the generated corrective characters*iwith charactersiappropriate combinations of k - selected and received data bits, in this case, if there is no distortion in two adjacent matching symbols replace all distorted combination of k - selected information bitsiin combination, appropriate corrective charactersifor the combination of k - selected data bits, and if there are differences in the two adjacent comparison *ii+1then correct the distorted adjacent combinations of k - selected and received information bits only for the case when the combination of the control bits is not distorted. Technical result achieved in the implementation of the invention is to increase the noise immunity of discrete information transmission 2 C.p. f-crystals, 1 Il.

The invention relates to the field of radiocommunications, telecommunications and computing, and more particularly to methods and devices for data transmission in computer networks.

Known methods of discrete information transmission (see, for example, [1] pages 357-369, [2] pages 200-231, the application for invention No. 99120097/09 from 17.12.1998 [3]).

In the known methods the transmission of discrete information is carried out by converting the message into a sequence of perceptible signals (code combinations, which change so that they have the ability to detect and correct errors in reception caused by interference, and to recover messages from received code combinations.

Known methods provide a robust connection, but have a large excess is appropriated method is a method, described in [1] page 358. The method includes transmitting end of a communication line conversion of the input message signal into a sequence of code combinations consisting of n information bits, is added to each code combination of information bits k - control bit, the combination of which is determined depending on the combination of n information bits, and on the receiving end of the communication line is carried out restoration messages from received code combinations and feeds it to the target device.

However, the prototype method has a drawback. With increasing noise in the communication line and active intrusion reduced immunity because correcting capability of the code is limited to input redundancy.

Thus, the invention solves the problem of increasing noise immunity due to noise conditions.

This is achieved by the known method of transmitting digital data, which consists in the conversion of the input message signal at the transmitting end of a communication line into a sequence of code combinations consisting of n information bits, are added to each code combination of information bits k - control bit, the combination of which is determined in zavisimost for the adopted code combinations and applying it to the target device according to the invention on the sending end of the line, a combination of k - the control bits are selected in accordance with the symbolidetermined by summing modulo P=2ksymbol aicorresponding to the combination of k - selected information bit symboli-1appropriate combinations of k - control bit of the previous code messagesii-1+ai(mod P), and on the receiving end of the communication line for each code combination form a corrective character and*ifor the selected combination of k information bits by adding modulo P=2kicorresponding to the received combination of the control bits, with the dual symbolwithi-1corresponding to the combination of the control bits of the previous code combination of the message and*ii+ci-1(mod P), whereci-1=P-i-1compare SFOR is selected and received information bits, if there is no distortion in two adjacent matching symbols replace all distorted combination of k - selected data bits andiin combination, appropriate corrective symbols a*ifor the combination of k - selected data bits, and if there are distortions in two adjacent matching symbols andiand*iand andi+1and*i+1then form a corrective characters*ifor combinations of control bits by adding modulo P=2ksymbol andicorresponding to the combination of k - selected and received information bits with all the previous characters corresponding to the combinations of k - selected and received data bits of this message*iai+*i-1(mod P), compare them with the symbolsiappropriate combinations of k - adopted control bit and correct distorted adjacent combinations of k - selected and received information bits if there are any discrepancies in the following two combinations of control

discrete information are messages or data written in binary code and represented by the signal as a sequence of zeros and a single bit;

the symbol is a number, for example, and recorded in the form of digits of the binary number system and is represented as a sequence (combination) of zero and a single bit, if we assume that the position of each biticorresponds to the binary digit a=200+211+222+... +2n-1n-1;

- the ratio of comparability (a=b(mod p)) and comparable to b modulo p: two numbers a and b are called comparable modulo p, if you divide both numbers by R residues are equal;

- addition of numbers a and b modulo p means that two numbers are added in the usual way, and their sum is translated into a nite set by comparing modulo R.

These distinctive features in comparison with the prototype allows to make a conclusion on the conformity of the proposed technical solution the criterion of "novelty".

In the proposed method provides higher noise immunity due in relation to the prototype, because the combination of the control bit added to the code combination of the message is determined not only by the combination of the information bits of a given code combination, and combinations of information bits of all the previous code combinations of messages. For the used encoding combinations of control bits for the distortion of a single coded combinations of control bits error when decoding this combination extends to neighboring decoded combination, and when distorted one combination of data bits in the encoding process control bit error applies to all subsequent coded combination. These properties are used by the code allows not only to detect distorted when receiving a combination of k - selected data bits and to correct any distorted bits of these code combinations on the receiving end of the communication line. Due to this increased the number of corrected bits in all of the transmitted message, which increases the robustness of the connection.

It is a new property set of features, leading to increased noise due to interference conditions and active intrusion, allows to conclude with the transmission of discrete information tested in laboratory conditions. An example implementation of this method using the device shown in the drawing, where:

unit 1 - the signal source;

unit 2 - the encoder;

block 3 - transmitter;

unit 4 - the receiver.

unit 5 - decoding device;

unit 6 - the target device.

Signal as a sequence of zeros and a single bit {1110000010000110001010011110100011100100101101110110} in unit 2 is converted into a sequence of code combinations{1110, 0000, 1000, 0110, 0010, 1001, 1110, 1000, 1110, 0100, 1011, 0111, 0110}, which corresponds to the sequence of characters{14, 0, 8, 6, 2, 9, 14, 8, 14, 4, 11, 7, 6}.

For ease of description of the operation of the device will assume that for each combination of the 4 data bits (n=4) add 3 control bits (k=3). In this case, P=2k=8. In each code combination choose 3 information bits, the combination of which will be subject to adjustment in the event of incorrect reception of bits. Selected sequences of combinations of information bits{110, 000, 000, 110, 010, 001, 110, 000, 110, 100, 011, 111, 110} match a sequence of characters and={6, 0, 0, 6, 2, 1, 6, 0, 6, 4, 3, 7, 6} and is determined by the formulaii-1+ai(mod P), the sequence solidautoeject combinations of control bits {110, 110, 110, 100, 110, 111, 101, 101, 011, 111, 010, 001, 111}. The control bits are added to information bits and the message in coded form{1110110, 0000110, 1000110, 0110100, 0010110, 1001111, 1110101, 1000101, 1110011, 0100111, 1011010, 0111001, 0110111} transfer devices 3 and 4 on the receiving end of the communication line. In a decoding device 5 adopted a distorted combination of correct data bits and the recovered message serves on the target device 6.

For example, if you receive a message each second code combination has distorted all the selected data bits, then the sequence of symbols received combinations would be a={1, 0, 7, 6, 5, 1, 1, 0, 1, 4, 4, 7, 1}, and calculated according to the formula and*ii+ci-1(mod P), whereci-1=P-i-1the sequence of corrective characters and*={6, 0, 0, 6, 2, 1, 6, 0, 6, 4, 3, 7, 6} will be different from that adopted in each of the second code combination. If the message control bits are not distorted, because otherwise there was divergence of the compared characters a and a*in two adjacent code combinations.following up on corrective symbols {6, 0, 2, 6, 6, 3, 6}, which corresponds to the bit combination{110, 000, 010, 110, 110, 011, 110}.

If distorted all the selected data bits in two adjacent combinations, for example in the third and fourth, and instead of code combinations {000, 110}, which correspond to the symbols {0, 6}, accepted combinations of {111, 001, which correspond to the symbols {7, 1}, then the sequence adopted is not distorted combinations of control bits, which corresponds to a sequence of characters={6, 6, 6, 4, 6, 7, 5, 5, 3, 7, 2, 1, 7}, will differ from that calculated by the formula*iandi+*i-1{mod P) sequence of corrective control characters{6, 6, 5, 6, 0, 1, 7, 7, 5, 1, 4, 3, 1} in all subsequent compare the characters. In this case, the only correct distorted information bits in two adjacent code combinations.

If the message is distorted all control bits, for example in the third combination, and instead of the code combinations of {110} will be adopted by the combination of {001}, and the information bits of the message is not distorted, then the sequence of characters for the combination of the received control bit*iai+*i-1(mod P) sequence of corrective control characters*={6, 6, 4, 4, 6, 7, 5, 5, 3, 7, 2, 1, 7} only one-third code combination and the sequence of characters for combinations of the received data bits and={6, 0, 0, 6, 2, 1, 6, 0, 6, 4, 3, 7, 6} will differ from the calculated sequence of corrective information symbols a=*{6, 0, 0, 3, 3, 1, 6, 0, 6, 4, 3, 7, 6} in the third and fourth code combinations. In this case, adjusted only all distorted control bits in the third code combinations.

For the considered example of the method of discrete information transmission when transmitting messages containing 30 code combinations using 4 white and 3 control bits can be corrected to 60 information bits that can be distorted in 20 code combinations. At the same time prototype method, in which control bits are chosen optimally to adjust one code combination, allows under the same conditions to correct one bit in the code combination, and considered the message to be adjusted up to 30 inform the years of the prototype method to the number of control bits in one code combination to increase to six. Only in this case, the message can be corrected 60 information bits.

If instead of the 3 control bits in the above example will be used 4 bits, the proposed method allows to correct up to 80 data bits in the message, while the efficiency of the prototype method will not change and will be 30 corrected bits in the message, since the optimal number of control bits k to adjust the r bit in the code combination is determined by the expression

Thus, the proposed method compared to the prototype provides better interference resistance of the connection.

If each code combination of data bits which must be corrected will choose depending on their importance, that reduces the damage caused by interference and active intrusion in the process of information transfer.

When determining combinations of control bits, and when computing information and control characters in the proposed method, instead of adding characters modulo P can be used in the operation bits bitwise addition modulo two.

Implementation of the proposed method is straightforward, since all the re.

Sources of information

1. Bychkov, S. I. Space radio systems. - M.: Soviet radio, 1967.

2. D. D. Klovsky Theory of signal transmission. - M.: Communication, 1973.

3. Device for encoding/decoding N-bit source words into corresponding M-bit channel words, and Vice versa. Application for invention No. 99120097/09 from 07.12.1998 - IPC 7 H 03 M 7/00.

Claims

1. The method of discrete information transmission in systems with feedback, including on the sending end of the line dividing the input signal into blocks of length n-bits, the sequence of blocks of length n-bits remember, form the message and transmit the generated message on the communication line, and on the receiving end of the line, remember the message, pass it through the feedback channel on the transmitting end of the line, take the message on the sending end of the line and compare the transmitted and received messages, pass on the receiving end of the communication line follow-up messages, if the comparison of the transmitted and received messages are the same, pass on the receiving end of the communication line commands for erasing messages if you compare the messages do not match, and re-transmit the generated message is mnom end of the line received message code each symbol in the message is determined in accordance with the formula

i=i-1+i(mod P),

where P=2n;

the characters,are numbers written as digits in the binary number system and is represented as a sequence (combination) of zero and a single bit;

i,ithe symbol and the encoded symbol generated messages;

i-1- previous encoded symbol generated message

and on the sending end of the line, the transmitted message code similarly as on the receiving end of the communication line, compare transmitted and received coded messages and transmit to the receiving end of the line commands for erasing messages if you compare the transmitted and the received encoded messages are differences in two or more adjacent characters.

2. The method according to p. 1, characterized in that the coding of messages at the receiving and transmitting ends of the link is performed by a bitwise slorenia.

3. The method according to p. 1 or 2, characterized in that the symbols of the transmitted message code on the transmitting end of the communication line correcting code that corrects single errors, and on the receiving end of the communication line perform decoding of the received symbols and their adjustment.



 

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