CN110792435A - Rapid coding algorithm for mud pulse - Google Patents

Abstract

The invention discloses a rapid coding algorithm of mud pulses, which adopts a multi-pulse time slot multiplexing technology, wherein a plurality of pulses share the same time slot coordinate, so that the number of required time slots is less when the pulse width and the data are the same, the transmission time is reduced, the coding efficiency is improved, meanwhile, the pulse width of the coding time slot is 1.5 times of the time slot width, the allowable deviation of the pulse position is larger under the same pulse width, and the coding fault tolerance is improved.

Description

Rapid coding algorithm for mud pulse

Technical Field

The invention relates to the field of petroleum drilling, in particular to a mud pulse rapid coding algorithm.

Background

In the field of petroleum drilling, a mud pulser is used for transmitting downhole data to the ground in real time in measurement while drilling. The underground data needs to be converted into a mud pressure pulse signal through coding, mud pressure pulses are collected on the ground, and are reversely decoded according to a coding mode to be restored into uploading data. With the upgrading and increasing of downhole measurement while drilling tools, the data volume needing to be uploaded also increases rapidly. The existing mud pulser data coding uses a pulse position coding method, has low coding efficiency and poor fault tolerance, and cannot meet the requirements of actual use.

Disclosure of Invention

The invention aims to provide a rapid coding algorithm of mud pulses, which solves the problem of improvement in the background technology.

The invention is realized in such a way that the rapid coding algorithm of the mud pulse comprises the following steps:

step 1: obtaining the number of the set coding pulses and the time slot width, and entering the step 2;

step 2: determining the number of time slots according to the number of pulses, and entering a step 3;

and step 3: initializing pulse positions, sequentially placing all pulses at the leftmost side of a time slot, placing a high-order pulse at the left side of a low-order pulse, initializing coded data to be 0, and entering a step 4;

and 4, step 4: obtaining coded data, and entering step 5;

and 5: comparing the coded data with the coded data, if equal, entering step 9, and if not equal, entering step 6;

step 6: if the current pulse is not at the rightmost end of the time slot which can be moved to, the pulse at the lowest position moves to the right for 1 time slot, the coded data is increased by 1, the step 8 is carried out, if the current pulse reaches the rightmost end of the time slot, the carry is required to be carried to the high position, and the step 7 is carried out;

and 7: the carry operation is as follows, the high-order pulse of the current moving pulse moves to the right by 1 bit, the current moving pulse and the low-order pulse thereof return to the time slot immediately adjacent to the right side of the high-order pulse, the coded data is increased by 1, and the step 5 is entered;

and 8: repeating the steps 5 and 6 until the coded data and the coded data are equal;

and step 9: converting the time slot and the pulse into a 0 and 1 sequence, coding the position of the time slot with the pulse into 1, coding the position of the time slot without the pulse into 0, obtaining a coded sequence, and finishing coding.

The further technical scheme of the invention is as follows: the width of the pulse is 1.5 times the slot width.

The invention has the beneficial effects that: the rapid coding algorithm of the mud pulse has the advantages that the number of the needed time slots is less when the pulse width and the data are the same through time slot multiplexing, the transmission time is reduced, the coding efficiency is improved, meanwhile, the pulse width of the coding time slot is 1.5 times of the time slot width, the allowable deviation of the pulse position is larger under the same pulse width, and the coding fault tolerance is improved.

Detailed Description

The first embodiment is as follows: the invention discloses a rapid coding algorithm of mud pulses, which comprises the following steps:

step 1: obtaining the number of the set coding pulses and the time slot width, and entering the step 2;

step 2: determining the number of time slots according to the number of pulses, and entering a step 3;

and step 3: initializing pulse positions, sequentially placing all pulses at the leftmost side of a time slot, placing a high-order pulse at the left side of a low-order pulse, initializing coded data to be 0, and entering a step 4;

and 4, step 4: obtaining coded data, and entering step 5;

and 5: comparing the coded data with the coded data, if equal, entering step 9, and if not equal, entering step 6;

step 6: if the current pulse is not at the rightmost end of the time slot which can be moved to, the pulse at the lowest position moves to the right for 1 time slot, the coded data is increased by 1, the step 8 is carried out, if the current pulse reaches the rightmost end of the time slot, the carry is required to be carried to the high position, and the step 7 is carried out;

and 7: the carry operation is as follows, the high-order pulse of the current moving pulse moves to the right by 1 bit, the current moving pulse and the low-order pulse thereof return to the time slot immediately adjacent to the right side of the high-order pulse, the coded data is increased by 1, and the step 5 is entered;

and 8: repeating the steps 5 and 6 until the coded data and the coded data are equal;

and step 9: converting the time slot and the pulse into a 0 and 1 sequence, coding the position of the time slot with the pulse into 1, coding the position of the time slot without the pulse into 0, obtaining a coded sequence, and finishing coding.

The method adopts a multi-pulse time slot multiplexing technology, a plurality of pulses share the same time slot coordinate, the pulses are not overlapped and crossed, and the positions of the pulses have correlation; the pulse width is 1.5 times of the slot width; the high-order pulse is positioned at the left side of the low-order pulse; the pulse position is shifted to the right by one slot to represent an increase of 1 in the encoded data; when the low-order pulse moves to the rightmost side of the time slot, a carry is generated from the low order to the high order, the high-order pulse moves to the right by one time slot, and meanwhile, the high-order weight correspondingly changes; the bit weight of the lowest pulse is always 1, the bit weight of the second lowest pulse is determined by the distance from the second lowest pulse to the rightmost end of the time slot, and the bit weight of the pulse above the second lowest pulse is determined by the pulse lower than the second lowest pulse; the rapid coding algorithm of the mud pulse has the advantages that the number of the needed time slots is less when the pulse width and the data are the same through time slot multiplexing, the transmission time is reduced, the coding efficiency is improved, meanwhile, the pulse width of the coding time slot is 1.5 times of the time slot width, the allowable deviation of the pulse position is larger under the same pulse width, and the coding fault tolerance is improved.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (2)

1. A rapid coding algorithm for mud pulses, characterized in that it comprises the following steps:

step 1: obtaining the number of the set coding pulses and the time slot width, and entering the step 2;

step 2: determining the number of time slots according to the number of pulses, and entering a step 3;

and step 3: initializing pulse positions, sequentially placing all pulses at the leftmost side of a time slot, placing a high-order pulse at the left side of a low-order pulse, initializing coded data to be 0, and entering a step 4;

and 4, step 4: obtaining coded data, and entering step 5;

and 5: comparing the coded data with the coded data, if equal, entering step 9, and if not equal, entering step 6;

step 6: if the current pulse is not at the rightmost end of the time slot which can be moved to, the pulse at the lowest position moves to the right for 1 time slot, the coded data is increased by 1, the step 8 is carried out, if the current pulse reaches the rightmost end of the time slot, the carry is required to be carried to the high position, and the step 7 is carried out;

and 7: the carry operation is as follows, the high-order pulse of the current moving pulse moves to the right by 1 bit, the current moving pulse and the low-order pulse thereof return to the time slot immediately adjacent to the right side of the high-order pulse, the coded data is increased by 1, and the step 5 is entered;

and 8: repeating the steps 5 and 6 until the coded data and the coded data are equal;

and step 9: converting the time slot and the pulse into a 0 and 1 sequence, coding the position of the time slot with the pulse into 1, coding the position of the time slot without the pulse into 0, obtaining a coded sequence, and finishing coding.

2. The algorithm of claim 1 wherein the width of the pulses is 1.5 times the width of the slots.