CN104753638B - A kind of chaos spread spectrum underwater acoustic communication method - Google Patents
A kind of chaos spread spectrum underwater acoustic communication method Download PDFInfo
- Publication number
- CN104753638B CN104753638B CN201510093138.5A CN201510093138A CN104753638B CN 104753638 B CN104753638 B CN 104753638B CN 201510093138 A CN201510093138 A CN 201510093138A CN 104753638 B CN104753638 B CN 104753638B
- Authority
- CN
- China
- Prior art keywords
- mrow
- signal
- spread spectrum
- binary message
- chaos
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Abstract
The invention discloses a kind of chaos spread spectrum underwater acoustic communication method, step includes：Step 1, by BnBe converted to each code element biiDuration is TbSquare-wave signal u0；Step 2, using chaotic signal u caused by hybrid system as chaos spread spectrum sequence；Step 3, the u for obtaining step 10The signal u being multiplied with the u that step 2 obtains after being spread1；Step 4, to signal u1Add synchronizing information, the signal u finally launched2；Step 5, receiving terminal use matched filter, and the output signal of the matched filter is u4；Step 6, to output signal u4Detected in particular moment and sign determination；Step 7, the decision symbol value multiplication by the corresponding spread-spectrum signal section of the decision symbol value corresponding to synchronizing information corresponding to every binary message, the binary message of transmission is recovered,.The method of the present invention, good confidentiality, accuracy rate are high.
Description
Technical field
The invention belongs to communication technical field, is related to a kind of chaos spread spectrum underwater acoustic communication method.
Background technology
2/3rds of ball surface product are taken up an area in ocean, contain the abundant energy.As shortage of resources, environmental pollution etc. are asked
Topic is become increasingly conspicuous, and sight is invested ocean by every country one after another, realizes the development and utilization of marine resources, and the too busy to get away underwater sound leads to
Letter.With the foundation of various communication networks, frequency spectrum resource is more crowded, and the interference between communication is even more serious, spread spectrum technique
It is a kind of very important Anti-jam Communication Technology.
Chaotic signal has wide spectrum, the characteristic such as initial value sensitivity and pulse auto-correlation function, is applied to communication system for it
System provides supremacy clause.Chaos is combined with spread spectrum and forms Chaotic Spread Spectrum Communication Technology.Conventional spread spectrum communication using it is pseudo- with
Machine sequence PN codes (such as m-sequence, gold sequences etc.) are used as spreading code.PN codes are produced by linear shift register, and its structure is fixed
And, it is known that with periodically, confidentiality is high, the shortcomings that a large amount of peak values occurs in cross-correlation function under multi-path environment.Due to chaos
Signal has aperiodicity, using chaotic signal as spreading code, can improve the performance of traditional pseudorandom spread spectrum code.Chaos expands
Frequency communication is broadly divided into two classes：Chaos two-value is spread and chaos real value spread spectrum, block diagram such as Fig. 1 and Fig. 2 of both communication systems
It is shown.Fig. 3, Fig. 4 and Fig. 5 are respectively digital information, chaos two-value spreading code and the expansion that chaos two-value spread spectrum communication system is sent
Signal after frequency, wherein chaos two-value spreading code quantify to obtain by chaotic signal, due to the precision of hardware, may lead
Chaos two-value spreading code is caused the short cycle occur；Meanwhile chaos two-value spread spectrum communication system needs the synchronization acquistion of spreading code, realize
Get up more difficult；Fig. 6, Fig. 7 and Fig. 8 are respectively digital information, the chaos real value spread spectrum that chaos real value spread spectrum communication system is sent
Signal after sequence and spread spectrum.Comparison diagram 7 is visible with Fig. 8 signal waveforms, before 0.5 second, chaos real value frequency expansion sequence and this
When the digital information " 1 " that sends be multiplied, keep constant；And after 0.5 second chaos real value frequency expansion sequence with " -1 " be multiplied so that it is mixed
The amplitude of ignorant real value frequency expansion sequence is overturn.The receiving terminal of chaos real value spread spectrum communication system needs to use filtering technique
(such as：EKF (EKF) algorithm, Unscented kalman filtering (UKF) algorithm or population filtering (PF)) estimate to mix
Ignorant frequency expansion sequence, the bit error rate are higher.But in the case of channel distortions serious (underwater acoustic channel), it is necessary to dropped using balancing technique
Low error rate, which increase the complexity of chaos real value spread spectrum communication system algorithm.
The content of the invention
It is an object of the invention to provide a kind of chaos spread spectrum underwater acoustic communication method, solves existing chaotic spread spectrum sequence
The problem of method system is complicated, and the bit error rate is higher.
The technical solution adopted in the present invention is a kind of chaos spread spectrum underwater acoustic communication method, to be embodied according to the following steps：
Step 1, binary message to be launched are expressed as Bn={ b1,b2,...,bn, wherein bii={ 1, -1 }, ii=1,
2 ..., n, biiWhat is represented is the i-th i positions binary message, by BnBe converted to each code element biiDuration is TbSquare wave
Signal u0；
Step 2, using chaotic signal u caused by hybrid system as chaos spread spectrum sequence, the hybrid system is by continuous state
Formed with discrete state, its expression formula is as follows：
WhenS (t)=sgn (u (t))；WhenS (t) keeps constant,
It is therein
Wherein, parameter w=2 π f, β=f ln2, integer f are signal baseband frequency；Discrete state s switching cycle is Tc
=2 π/w=1/f, the binary character of discrete state behalf are expressed as si, i=1,2 ..., l, l represent discrete state s
The number of symbol switching,
Spreading gain is defined as L=Tb/Tc；
Step 3, the square-wave signal u that will be obtained in step 10It is multiplied and is expanded with the chaos spread spectrum sequence u obtained in step 2
Signal u after frequency1, expression formula u1=u0×u；
Step 4, to the signal u after spread spectrum1Add synchronizing information, the signal u finally launched2,
Choose every binary message biiAny one position in the discrete spreading code contained in corresponding frequency expansion sequence u, such as
Synchronizing information of the chaotic signal fragment as the binary message corresponding to jth position, j=1,2 ..., L, this is synchronously believed
Breath is placed on the front or behind of signal after every binary message spread spectrum；Every binary message selects different positions as needed
Discrete spreading code corresponding to chaotic signal fragment as synchronizing information, to design different selection rules and insertion position,
This is advantageous to the confidentiality of raising system；
Step 5, receiving terminal use matched filter, and the filter expression is as follows：
Wherein, parameter w, β, TcDefinition is with consistent above, the signal u that will be received3Input as the matched filter is believed
Number, the output signal of the matched filter is u4；
Step 6, to output signal u4Detected in particular moment and sign determination,
If time-ofday signals u4The value of detection is determined as 1 more than 0, if time-ofday signals u4The value of detection is less than 0 judgement
For -1, its symbol detection expression formula is：
σjj=sgn (u4(jjTc- Δ t)), (4)
Wherein Δ t is time delay, and it is that jj is represented for which test point；
Step 7, by the corresponding spread spectrum of the decision symbol value corresponding to synchronizing information corresponding to every binary message
The decision symbol value of signal segment is multiplied, it becomes possible to the binary message of transmission is recovered,
If the corresponding spread spectrum information discrete code section of synchronizing information decision symbol value corresponding to every binary message
Decision symbol value is identical, then the binary message of original transmitted is 1, and otherwise, the binary message of original transmitted is just -1, is obtained
Corresponding square-wave signal u5,.
The invention has the advantages that specifically include：
1) during the symbol s spread spectrums that chaotic signal includes in itself in the inventive method PN codes are similar to spread, and continuous chaos
Chaos real value is similar to when signal u is spread to spread.The fundamental frequency of this chaotic signal can be realized by parameter setting, flexible to adapt to
Channel width；Without Channel Modulation-demodulation after spread spectrum, the structure of communication system is simplified；In addition, what the inventive method used
Chaos spread spectrum sequence avoids due to quantization without quantifying and causes chaos sequence short-period problem occur.
2) the inventive method reduces multipath and influence of noise using chaos matched filter, it is not necessary to using balancing technique,
Simplify the structure of communication system.Still can be with proper communication in the case where noise floods signal, there is system good resisting to do
Immunity and low error rate.
3) despreading method of the inventive method is simple.In traditional chaos two-value spread spectrum system, if receiving terminal do not know it is original
Chaos spread spectrum sequence, it is necessary to carry out the synchronization acquistion of spreading code so that receiving terminal frequency expansion sequence reaches with transmitting terminal frequency expansion sequence
Precise synchronization, this make it that system architecture is complicated, implemented more difficult.In traditional chaos real value spread spectrum system, using EKF,
UKF, PF algorithm realize the synchronization of chaos spread spectrum sequence, but the algorithm is very sensitive to multipath channel and noise, causes error code
Rate is very high.And in context of methods, it is only necessary to which the signal that chaos matched filter exports exists according to the selection rule of synchronizing information
Corresponding moment detection symbols can simply recover original transmitted information, and despreading method is simple.
4) bit error rate is low.The inventive method has the lower bit error rate compared with traditional Chaotic Spread Spectrum Communication System.
5) the inventive method has good confidentiality.It is embodied on the selection rule and insertion position of synchronizing information.
6) transmission signal is noise like broadband signal, small on organism in water and Underwater Acoustic Environment influence, does not interfere with dolphin, whale
The navigation feature of the biology such as fish, have environment friendly higher.
Brief description of the drawings
Fig. 1 is existing chaos two-value spread spectrum system block diagram；
Fig. 2 is existing chaos real value spread spectrum system block diagram；
Fig. 3 is the wavy curve of transmitting information；
Fig. 4 is chaos two-value spreading code wavy curve；
Fig. 5 is signal waveform curve after being spread in chaos two-value spread spectrum system；
Fig. 6 is the wavy curve of transmitting information；
Fig. 7 is chaos real value frequency expansion sequence wavy curve；
Fig. 8 is the signal waveform curve after being spread in chaos real value spread spectrum system；
Fig. 9 is the chaos spread spectrum underwater sound communication system block diagram of the inventive method；
The wavy curve of two binary messages of transmission is assumed when Figure 10 is emulation；
Figure 11 is the chaos spread spectrum sequence wavy curve that the inventive method uses；
Figure 12 is the signal waveform curve after the inventive method spread spectrum；
Figure 13 is that the signal that synchronizing information is inserted into before spread-spectrum signal by the inventive method launches format chart；
Figure 14 is the signal waveform that the inventive method adds synchronizing information before spread-spectrum signal, i.e., the letter transmitted in channel
Number wavy curve；
Figure 15 is that the signal that synchronizing information is inserted into behind spread-spectrum signal by the inventive method launches format chart；
Figure 16 is the signal waveform that the inventive method adds synchronizing information behind spread-spectrum signal, i.e., is transmitted in channel
Signal waveform curve；
Figure 17 is the signal waveform curve received in the inventive method to solid-line signals in Figure 14 after underwater acoustic channel；
Figure 18 is the wavy curve of the inventive method chaos matched filter output signal；
Figure 19 is the original transmitted signal wavy curve that the inventive method recovers；
Figure 20 is that the bit error rate of the existing method from the inventive method under different bit state of signal-to-noise changes correlation curve.
Embodiment
The inventive method is described in detail with reference to the accompanying drawings and detailed description.
The chaos spread spectrum underwater acoustic communication method of the present invention, is embodied according to the following steps：
Step 1, binary message to be launched are expressed as Bn={ b1,b2,...,bn, wherein bii={ 1, -1 }, ii=1,
2 ..., n, biiWhat is represented is the i-th i positions binary message, by BnBe converted to each code element biiDuration is TbSquare wave
Signal u0；
Step 2, using chaotic signal u caused by hybrid system as chaos spread spectrum sequence, the hybrid system is by continuous state
Formed with discrete state, its expression formula is as follows：
WhenS (t)=sgn (u (t))；WhenS (t) keeps constant,
It is therein
Wherein, parameter w=2 π f, β=f ln2, integer f are signal baseband frequency；Discrete state s switching cycle is Tc
=2 π/w=1/f, the binary character of discrete state behalf are expressed as si, i=1,2 ..., l, l represent discrete state s
The number of symbol switching,
Spreading gain is defined as L=Tb/Tc；
Step 3, the square-wave signal u that will be obtained in step 10It is multiplied and is expanded with the chaos spread spectrum sequence u obtained in step 2
Signal after frequency is u1, its expression formula is u1=u0×u；
Step 4, to the signal u after spread spectrum1Add synchronizing information, i.e., the signal u finally launched2,
Choose every binary message biiAny one position in the discrete spreading code contained in corresponding frequency expansion sequence u, such as
Synchronizing information of the chaotic signal fragment as the binary message corresponding to jth position, j=1,2 ..., L, this is synchronously believed
Breath is placed on the front or behind of signal after every binary message spread spectrum；
Moreover, every binary message selects chaotic signal fragment corresponding to the discrete spreading code of different positions to make as needed
For synchronizing information, to design different selection rules and insertion position, this is advantageous to the confidentiality of raising system.
Step 5, receiving terminal are as follows using (chaos) matched filter, the filter expression：
Wherein, parameter w, β, TcDefinition is with consistent above, the signal u that will be received3Input as the matched filter is believed
Number, the output signal of the matched filter is u4, the wave filter filtered out noise, reduced the influence of multipath effect；
Step 6, to output signal u4Detected in particular moment and sign determination,
If time-ofday signals u4The value of detection is determined as 1 more than 0, if time-ofday signals u4The value of detection is less than 0 judgement
For -1, its symbol detection expression formula is：
σjj=sgn (u4(jjTc- Δ t)), (4)
Wherein Δ t is time delay, preferably Tc15%, jj represent be which test point；
Step 7, by the corresponding spread spectrum of the decision symbol value corresponding to synchronizing information corresponding to every binary message
The decision symbol value of signal segment is multiplied, it becomes possible to the binary message of transmission is recovered,
If the corresponding spread spectrum information discrete code section of synchronizing information decision symbol value corresponding to every binary message
Decision symbol value is identical, then the binary message of original transmitted is 1, and otherwise, the binary message of original transmitted is just -1, is obtained
Corresponding square-wave signal u5,.
Reference picture 9, the operation principle of the inventive method are, by transmitting information Bn={ b1,b2,...,bnBe converted to square wave
Signal u0, biiRepresent the i-th i positions binary message, bii={ 1, -1 }, ii=1,2 ..., n, this square-wave signal is with mixing
Chaos spread spectrum sequence u caused by system is multiplied, and such as formula (1), obtains the chaos spread spectrum signal u of carrying information1；Chaos spread spectrum is chosen again
A segment signal in sequence u is inserted into spread-spectrum signal u as synchronizing information1In, obtain the signal u of addition synchronizing information2；This letter
Number after underwater acoustic channel, by reception signal u3As the input signal of matched filter, such as formula (3), wave filter output is obtained
Signal u4；To this output signal u4Detected and sign determination in proper timing, finally by synchronizing information decision symbol value and its
Corresponding spread spectrum information decision symbol value is multiplied, it is possible to recovers original transmitted information B'n。
Embodiment
Step 1, binary message B to be launchedn={ b1,b2,...,bnBe converted to each code element biiDuration is Tb
Square-wave signal u0, wherein bii={ 1, -1 }, ii=1,2 ..., n, biiWhat is represented is the i-th i positions binary message.This reality
Apply official holiday and set two i.e. B of binary message of n=2 transmissions2={ b1,b2, if by B2Be converted to each code element duration Tb=
0.5s square-wave signal u0, as shown in Figure 10.
Step 2, by the use of chaotic signal u caused by hybrid system as frequency expansion sequence, the hybrid system by continuous state and
Discrete state forms, and its expression formula is as follows：
WhenS (t)=sgn (u (t))；WhenS (t) keeps constant.Wherein：
Wherein, parameter w=2 π f, β=f ln2, integer f are signal baseband frequency；Discrete state s switching cycle is Tc
=2 π/w=1/f, the binary character of discrete state behalf are expressed as si, i=1,2 ..., l, l represent discrete state s
The number of symbol switching,
Then spreading gain is defined as L=Tb/Tc, the value of the present embodiment is f=8, then discrete spreading code s switching cycle
For Tc=0.125s, spreading gain L=Tb/Tc=0.5/0.125=4.
It is shown in solid in chaos spread spectrum sequence u such as Figure 11 caused by hybrid system (1).
Step 3, the signal u to be sent that will be obtained in step 10It is multiplied to obtain with the chaos spread spectrum sequence u obtained in step 2
Signal u after spread spectrum1It is as seen from Figure 12, (preceding in the code-element period when transmitting binary message is 1 as Figure 12 is shown in solid
Signal u in 0.5s)1It is identical with signal u；When transmitting binary message is -1, in code-element period (rear 0.5s) the interior signal u1With letter
Number u is compared to being overturn.In Figure 11 and Figure 12, si、s'iDiscrete state and spread spectrum respectively in chaos spread spectrum sequence are believed
Discrete state in number.Compares figure 11 is visible with Figure 12, and the inventive method uses continuous chaotic signal as frequency expansion sequence, wherein
Also the discrete spreading code s' to be changed after the discrete spreading code s and spread spectrum of similar PN codes is included, it has chaos real value spread spectrum concurrently
The characteristics of both being spread with PN codes.
Step 4, to the signal u after spread spectrum1Add synchronizing information, the signal u finally launched2.Synchronizing information is specifically square
Method is to choose every binary message (bii) corresponding in the discrete spreading code that contains in frequency expansion sequence (u) jth (j=1,
2 ..., L) synchronizing information of the chaotic signal fragment as the binary message corresponding to position, this synchronizing information can be put
The front or behind of signal after every binary message is spread.In addition, every binary message can select different positions
Chaotic signal fragment corresponding to discrete spreading code is as synchronizing information, by designing different selection rules and insertion position, this
Be advantageous to the confidentiality of raising system.
The present embodiment chooses frequency expansion sequence corresponding to every binary message, as the duration is LT in Figure 11c=0.5s,
T1And T2Solid-line signals corresponding to section, by the contain in this frequency expansion sequence the 3rd discrete spreading code (duration Tc=
It is TT in 0.125s, Figure 111And TT2Section corresponding to dotted line signal) corresponding to chaotic signal fragment as this binary message
Synchronizing information, this synchronizing information is inserted into before spread-spectrum signal as shown in solid in Figure 13 and Figure 14, can also be inserted
As shown in solid in Figure 15 and Figure 16 behind to spread-spectrum signal.The letter for adding synchronizing information is can be seen that from Figure 14 and Figure 16
The discrete state symbol contained in number is s ", and it is made up of the symbol s ' contained in the symbol s and spread-spectrum signal in synchronizing information,
The binary character that discrete state represents is s "=[s3,s′1,s′2,s′3,s′4,s7,s′5,s′6,s′7,s′8] or s "=
[s′1,s′2,s′3,s′4,s3,s′5,s′6,s′7,s′8,s7].In addition, every binary message can select the discrete of different positions
Chaotic signal fragment is as synchronizing information corresponding to spreading code.
Step 5, reception signal is sent into (chaos) matched filter it is filtered processing, the filter expression is：
Wherein, parameter w, β, TcDefine, in the present embodiment transmission signal u identical with front2(such as Figure 14 is shown in solid) passes through
After underwater acoustic channel (underwater acoustic channel parameter is as shown in table 1), the signal u that receives3As Figure 17 is shown in solid, using this signal as filter
The input signal of ripple device, obtain the output signal u of wave filter4, the wave filter filtered out noise, reduced the shadow of multipath effect
Ring.
Step 6, the output signal u to wave filter4Detected in particular moment and sign determination, if time-ofday signals u4
The value of detection is determined as 1 more than 0, if time-ofday signals u4The value of detection is determined as -1 less than 0, its symbol detection formula
For：
σjj=sgn (u4(jjTc- Δ t)), (4)
Wherein Δ t is time delay, is taken as Tc15%, jj represent be which test point.
10 detection time t are marked as shown in figure 181-t10, it is seen that t1=Tc- Δ t=0.1063s, t4=4Tc-Δ
T=0.4813s corresponds to σ1=sign (u4(t1))=- 1, σ4=sign (u4(t4))=- 1；In t6=6Tc- Δ t=.7313s, t9
=9Tcσ at-Δ t=1.1063s6=sign (u4(t6))=- 1, σ9=sign (u4(t9))=1.
Step 7, by the corresponding expansion of synchronizing information decision symbol value corresponding to every binary message in reception signal
The decision symbol value of frequency information corresponding positions is multiplied, and has just recovered the binary message of transmitting.It is if same corresponding to binary message
It is identical to walk the corresponding spread spectrum information decision symbol value of information decision symbol value, then the binary message of original transmitted is 1, no
Then, the binary message of original transmitted is just -1.In the present embodiment, the σ that obtains according to step 61、σ6And σ4、σ9It is multiplied respectively,
Produce b '1=σ1×σ4=1, b '2=σ6×σ9=-1, then it can recover the binary message B ' of original transmitted2=B2=1 ,-
1 }, its corresponding square-wave signal is u5As shown in figure 19.
The underwater acoustic channel parameter of table 1
| Parameter name | Parameter value |
| Sea water advanced h | 100 meters |
| Transmitting terminal is away from water surface distance d1 | 30 meters |
| Receiving terminal is away from water surface distance d2 | 50 meters |
| Propagation distance R | 1200 meters |
| Sound velocity in seawater c | 1539m/s |
| Bottom sound speed c1 | 1650m/s |
| Density of sea water ρ | 1023kg/m3 |
| Seafloor density ρ1 | 1500kg/m3 |
| Seawater salinity S | 1.5 |
| Multipath number | 2 |
| The sea of multipath 1, sub-bottom reflection number s, b | 1 1 |
| The sea of multipath 2, sub-bottom reflection number s, b | 2 3 |
The effect of method to illustrate the invention, underwater acoustic channel parameter as shown in table 1 and carrier frequency as shown in table 2,
In the case of the identicals such as spreading gain, by the inventive method and existing chaotic spread spectrum method simultaneously using shown in the last column of table 2
Rate of information throughput numerical value, the ber curve under different bit state of signal-to-noise is as shown in figure 20, it is seen then that present invention side
Method is in the case where bit signal to noise ratio is more than 10dB, the bit error rate zero, in the case where bit signal to noise ratio is less than 10dB, the present invention
For the method for proposition in the case where traffic rate is suitable, the bit error rate is minimum.
Parameter value when 2 different chaotic spread spectrum methods of table compare
In summary, the inventive method, as frequency expansion sequence, utilizes this using continuous chaotic signal caused by hybrid system
Hybrid system produces the discrete spreading code feature contained in signal, and the continuous signal fragment for taking out one section of discrete spreading code of correspondence is made
It is added to and is sent in signal for synchronizing information (or being synchronization frame), makes despreading simple, easy；In receiving terminal use and transmitting terminal
Corresponding chaos matched filter, reducing noise and Multipath Transmission influences, and realizes low error rate underwater sound communication well.
Claims (2)
1. a kind of chaos spread spectrum underwater acoustic communication method, it is characterised in that be embodied according to the following steps：
Step 1, binary message to be launched are expressed as Bn={ b1,b2,...,bn, wherein bii={ 1, -1 }, ii=1,
2 ..., n, biiWhat is represented is the i-th i positions binary message, by BnBe converted to each code element biiDuration is TbSquare wave
Signal u0；
Step 2, using chaotic signal u caused by hybrid system as chaos spread spectrum sequence, the hybrid system by continuous state and from
Bulk state forms, and its expression formula is as follows：
<mrow>
<mover>
<mi>u</mi>
<mo>&CenterDot;&CenterDot;</mo>
</mover>
<mo>-</mo>
<mn>2</mn>
<mi>&beta;</mi>
<mover>
<mi>u</mi>
<mo>&CenterDot;</mo>
</mover>
<mo>+</mo>
<mrow>
<mo>(</mo>
<msup>
<mi>&omega;</mi>
<mn>2</mn>
</msup>
<mo>+</mo>
<msup>
<mi>&beta;</mi>
<mn>2</mn>
</msup>
<mo>)</mo>
</mrow>
<mrow>
<mo>(</mo>
<mi>u</mi>
<mo>-</mo>
<mi>s</mi>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mn>0</mn>
<mo>,</mo>
<mo>-</mo>
<mo>-</mo>
<mo>-</mo>
<mrow>
<mo>(</mo>
<mn>1</mn>
<mo>)</mo>
</mrow>
</mrow>
WhenWhenKeep constant,
It is therein
Wherein, parameter w=2 π f, β=f ln2, integer f are signal baseband frequency；Discrete state s switching cycle is Tc=2 π/w
=1/f, the binary character of discrete state behalf are expressed as si, i=1,2 ..., l, l represent discrete state s symbols and cut
The number changed,
Spreading gain is defined as L=Tb/Tc；
Step 3, the square-wave signal u that will be obtained in step 10It is multiplied with the chaos spread spectrum sequence u obtained in step 2 after obtaining spread spectrum
Signal u1, expression formula u1=u0×u；
Step 4, to the signal u after spread spectrum1Add synchronizing information, the signal u finally launched2, choose every binary message
biiAny one position in the discrete spreading code contained in corresponding frequency expansion sequence u, the chaotic signal fragment conduct as corresponding to jth position
The synchronizing information of the binary message, j=1,2 ..., L, believe after the synchronizing information is placed on into every binary message spread spectrum
Number front or behind；
Every binary message selects chaotic signal fragment corresponding to the discrete spreading code of different positions to believe as synchronous as needed
Breath, to design different selection rules and insertion position, this is advantageous to the confidentiality of raising system；
Step 5, receiving terminal use matched filter, and the filter expression is as follows：
<mrow>
<mfenced open = "{" close = "">
<mtable>
<mtr>
<mtd>
<mrow>
<msub>
<mover>
<mi>u</mi>
<mo>&CenterDot;&CenterDot;</mo>
</mover>
<mn>4</mn>
</msub>
<mrow>
<mo>(</mo>
<mi>t</mi>
<mo>)</mo>
</mrow>
<mo>+</mo>
<mn>2</mn>
<mi>&beta;</mi>
<msub>
<mover>
<mi>u</mi>
<mo>&CenterDot;</mo>
</mover>
<mn>4</mn>
</msub>
<mrow>
<mo>(</mo>
<mi>t</mi>
<mo>)</mo>
</mrow>
<mo>+</mo>
<mrow>
<mo>(</mo>
<msup>
<mi>&omega;</mi>
<mn>2</mn>
</msup>
<mo>+</mo>
<msup>
<mi>&beta;</mi>
<mn>2</mn>
</msup>
<mo>)</mo>
</mrow>
<mrow>
<mo>(</mo>
<msub>
<mi>u</mi>
<mn>4</mn>
</msub>
<mo>(</mo>
<mi>t</mi>
<mo>)</mo>
<mo>-</mo>
<mi>&eta;</mi>
<mo>(</mo>
<mi>t</mi>
<mo>)</mo>
<mo>)</mo>
</mrow>
<mo>=</mo>
<mn>0</mn>
</mrow>
</mtd>
</mtr>
<mtr>
<mtd>
<mrow>
<mover>
<mi>&eta;</mi>
<mo>&CenterDot;</mo>
</mover>
<mo>=</mo>
<msub>
<mi>u</mi>
<mn>3</mn>
</msub>
<mrow>
<mo>(</mo>
<mi>t</mi>
<mo>+</mo>
<msub>
<mi>T</mi>
<mi>c</mi>
</msub>
<mo>)</mo>
</mrow>
<mo>-</mo>
<msub>
<mi>u</mi>
<mn>3</mn>
</msub>
<mrow>
<mo>(</mo>
<mi>t</mi>
<mo>)</mo>
</mrow>
</mrow>
</mtd>
</mtr>
</mtable>
</mfenced>
<mo>,</mo>
<mo>-</mo>
<mo>-</mo>
<mo>-</mo>
<mrow>
<mo>(</mo>
<mn>3</mn>
<mo>)</mo>
</mrow>
</mrow>
Wherein, parameter w, β, TcDefinition is with consistent above, the signal u that will be received3As the input signal of the matched filter,
The output signal of the matched filter is u4；
Step 6, to output signal u4Detected in particular moment and sign determination,
If time-ofday signals u4The value of detection is determined as 1 more than 0, if time-ofday signals u4The value of detection is determined as less than 0-
1, its symbol detection expression formula is：
σjj=sgn (u4(jjTc- Δ t)), (4)
Wherein Δ t is time delay, and it is that jj is represented for which test point；
Step 7, by the corresponding spread-spectrum signal of the decision symbol value corresponding to synchronizing information corresponding to every binary message
The decision symbol value of section is multiplied, it becomes possible to the binary message of transmission is recovered,
If the judgement of the corresponding spread spectrum information discrete code section of synchronizing information decision symbol value corresponding to every binary message
Value of symbol is identical, then the binary message of original transmitted is 1, and otherwise, the binary message of original transmitted is just -1, is obtained correspondingly
Square-wave signal u5,.
2. chaos spread spectrum underwater acoustic communication method according to claim 1, it is characterised in that：In described step 5, employ
Chaos matched filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510093138.5A CN104753638B (en) | 2015-03-02 | 2015-03-02 | A kind of chaos spread spectrum underwater acoustic communication method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510093138.5A CN104753638B (en) | 2015-03-02 | 2015-03-02 | A kind of chaos spread spectrum underwater acoustic communication method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104753638A CN104753638A (en) | 2015-07-01 |
| CN104753638B true CN104753638B (en) | 2017-11-28 |
Family
ID=53592805
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510093138.5A Active CN104753638B (en) | 2015-03-02 | 2015-03-02 | A kind of chaos spread spectrum underwater acoustic communication method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104753638B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105515683B (en) * | 2015-12-23 | 2017-11-28 | 西安理工大学 | Differential Chaos Shift Keying communication means based on hybrid system |
| CN106291515A (en) * | 2016-07-20 | 2017-01-04 | 中北大学 | A kind of chaos Sonar Signal production method |
| CN108449297B (en) | 2018-02-08 | 2020-09-25 | 西安理工大学 | Phase separation differential chaos keying communication method based on hybrid system |
| CN109474305B (en) * | 2018-12-05 | 2020-05-26 | 唐山照澜海洋科技有限公司 | 5G multi-carrier spread spectrum underwater acoustic communication method |
| CN109495128B (en) * | 2018-12-05 | 2020-09-08 | 北京控制与电子技术研究所 | Chaos sequence-based 5G multi-carrier spread spectrum underwater acoustic communication method |
| AU2018451596B2 (en) * | 2018-12-05 | 2022-12-01 | Beijing Institute Of Control And Electronic Technology | 5G multi-carrier spread spectrum underwater acoustic communication method |
| CN110365365B (en) * | 2019-07-19 | 2021-04-06 | 西安理工大学 | Multi-system differential chaotic keying method based on chaotic formed filtering |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1592161A (en) * | 2003-08-29 | 2005-03-09 | 中国科学院声学研究所 | M-ary spread spectrum communication method |
| CN101645743A (en) * | 2009-03-24 | 2010-02-10 | 中国科学院声学研究所 | Chaotic sequence-based packet M element spread spectrum communication method and device |
-
2015
- 2015-03-02 CN CN201510093138.5A patent/CN104753638B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1592161A (en) * | 2003-08-29 | 2005-03-09 | 中国科学院声学研究所 | M-ary spread spectrum communication method |
| CN101645743A (en) * | 2009-03-24 | 2010-02-10 | 中国科学院声学研究所 | Chaotic sequence-based packet M element spread spectrum communication method and device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104753638A (en) | 2015-07-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104753638B (en) | A kind of chaos spread spectrum underwater acoustic communication method | |
| Ren et al. | A chaotic spread spectrum system for underwater acoustic communication | |
| Sozer et al. | Direct sequence spread spectrum based modem for under water acoustic communication and channel measurements | |
| CN101645743B (en) | Chaotic sequence-based packet M element spread spectrum communication method and device | |
| CN103312637B (en) | Method and apparatus for estimating offset value, receiving apparatus, and method of processing signal in receiving apparatus | |
| CN103501201B (en) | A kind of frequency hopping arteries and veins position based on linear FM signal coding underwater acoustic communication method | |
| CN101567727A (en) | Differential cyclic shift spread-spectrum underwater sound communication method | |
| CN103905085B (en) | One is burst hybrid spread spectrum underwater sound concealed communication method | |
| CN102170314A (en) | Hyperbolic frequency-modulation spread spectrum acoustic communication method | |
| CN106936514A (en) | The underwater sound targeting signal detection method concentrated based on energy under condition of sparse channel | |
| CN105490974A (en) | Doppler estimation method of MIMO-OFDM hydroacoustic communication system | |
| CN107769862A (en) | A kind of bionical low communication interception method | |
| Peña et al. | Implementation of Code Shift Keying signalling technique in GALILEO E1 signal | |
| CN113300993B (en) | Transmission method for bit field superposition pseudo-random sequence and sparse cascade coding | |
| CN104168233A (en) | DSSS/UQPSK signal pseudo code sequence estimation method based on characteristic decomposition and Messay algorithm | |
| CN102243309A (en) | Method and apparatus for restraining cross-correlation interference in GNSS | |
| CN106453192A (en) | Symbol synchronization method and system based on shielding complementary binary sequence pair | |
| CN106972895A (en) | Underwater sound targeting signal detection method based on accumulation coefficient correlation under condition of sparse channel | |
| CN111555856B (en) | Guiding auxiliary synchronization method based on multipath differential weighted correlation | |
| CN101616110B (en) | Method and device for evaluating frequency offset | |
| Yin et al. | Multiuser underwater acoustic communication using single-element virtual time reversal mirror | |
| CN102315883B (en) | Encoding underwater sound communication method of Pattern delay inequality based on non-fixed code element width | |
| CN110224958A (en) | A kind of orthogonal wideband modulation-demo-demodulation method based on chaos sequence | |
| CN106385392A (en) | Low-intercept probability communication waveform design method based on chaotic keying | |
| CN106910508A (en) | A kind of hidden underwater acoustic communication method of imitative ocean piling sound source |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |