Method for prolonging elastic wave through-the-earth communication distance
A communication distance and flexible technology, applied in the direction of digital transmission system, electrical components, error prevention, etc., to achieve the effect of improving processing gain and extending communication distance
Inactive Publication Date: 2015-07-01
SHANDONG UNIV OF SCI & TECH
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[0004] The purpose of the present invention is to solve the problem of carrying out emergency rescue when danger occurs, and when the existing communication system is affected, the idea of spread spectrum communication is used for reference to time-expand the pulse width of the signal source output symbols, and then use the extended symbols Modulate the pseudo-random sequence so that the receiving end can obtain additional processing gain when performing correlation reception, improve receiving sensitivity, and extend the communication distance accordingly when the transmitting power of the sending end remains unchanged
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[0055] The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.
[0056] A method for prolonging the communication distance of elastic waves through the ground, comprising the following specific steps:
[0057] Step 1: Take 1024 bits as a piece of data with complete meaning, divide it into 64 frames, each frame is 16 bits, add a start marker frame before the start of 64 frames, and add an end marker frame at the end, so that all the data is 66 frames, that is, 1056 bits;
[0058] Step 2: Convert this total of 1056 bits of data to the bit rate 200bit / s, sent continuously figure 2 For the rate converter shown, the total time required for the entire sending process is: 1056(bit)÷200(bit / s)=5280ms, that is, it takes 5280 ms for the rate converter to receive all 66 frames of data;
[0059] Step 3: Write data in 1 frame figure 2 After buffering in the rate converter, the rate converter then rates t...
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The invention discloses a method for effectively prolonging an elastic wave through-the-earth communication distance under the condition of no changes in a signal transmission bandwidth, and belongs to the technical field of through-the-earth communication. The method is characterized in that a rate changer is used for finishing the time spreading of a bit code element with different input and output clocks, spreading a pulse width into M times an original pulse width, generating a pseudo-random sequence for local pseudo-noise (PN) codes at rate the same as the output rate of a signal source, outputting the pseudo-random sequence, and performing pseudo-random sequence spreading with the time-spread code element; and after a signal is transmitted to a receiving unit, the code element de-spread and demodulated by a synchronization unit is output to a rate inverse changer at rate fc, and is read to a terminal output unit at rate fs. According to the method, a high processing gain can be obtained under the condition of no changes in the signal transmission bandwidth, and under the condition of no changes in the sensitivity of a receiver, the through-the-earth communication distance of an elastic wave signal is equivalently prolonged; and the method is applied to non-real-time data communication, and can be effectively applied to the emergency relief communication of a mine.
Description
technical field [0001] The invention belongs to the technical field of ground-penetrating communication, and in particular relates to a method for extending the distance of elastic wave ground-penetrating communication. Background technique [0002] In the production process of coal mines and other underground mines, safety accidents occur from time to time, such as water penetration, gas explosions, fires, etc., which not only cause casualties and property losses, but also destroy the existing communication channels, making it impossible for underground and ground Contact, unable to know the specific situation of the underground personnel, affecting the progress of the rescue. Because the ground-penetrating communication uses the earth as a transmission channel, the channel characteristics are stable and not affected by accidents, so the ground-penetrating communication can become a reliable support means for rescue. [0003] Several current ground-penetrating communicatio...
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IPC IPC(8): H04L27/26H04L1/00
Inventor 郝建军王凤瑛丁晓明孙绪保颜斌
Owner SHANDONG UNIV OF SCI & TECH