CN114826848A - Communication method of enhanced high-efficiency short-parameter DCSK chaotic communication system - Google Patents
Communication method of enhanced high-efficiency short-parameter DCSK chaotic communication system Download PDFInfo
- Publication number
- CN114826848A CN114826848A CN202210210354.3A CN202210210354A CN114826848A CN 114826848 A CN114826848 A CN 114826848A CN 202210210354 A CN202210210354 A CN 202210210354A CN 114826848 A CN114826848 A CN 114826848A
- Authority
- CN
- China
- Prior art keywords
- signal
- chaotic
- dcsk
- information
- reference signal
- 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.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/001—Modulated-carrier systems using chaotic signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J13/00—Code division multiplex systems
- H04J13/0007—Code type
- H04J13/004—Orthogonal
- H04J13/0048—Walsh
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0018—Arrangements at the transmitter end
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0024—Carrier regulation at the receiver end
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
The invention requests to protect a communication method of an enhanced high-efficiency short-parameter DCSK chaotic communication system, and belongs to the technical field of communication. Which comprises the following steps: step 1: generating a chaotic reference signal by using a second-order Chebyshev polynomial function; step 2: modulating an information signal and transmitting a signal; and step 3: channel transmission: and 4, step 4: the receiving end demodulates the received signal and restores the information signal. The method is characterized in that the defects of low data rate and low energy efficiency of a classical short-spread differential chaos keying (SR-DCSK) modulation technology are improved in a related mode, a reference signal with the length of R is adopted at a transmitting end to be transmitted in the same first frame duration as the SR-DCSK, an orthogonal signal base is used for transmitting the addition of 2N orthogonal information signals in the second frame duration, and a data signal and the corresponding reference signal are correlated at a receiver to restore the information signals.
Description
Technical Field
The invention belongs to the technical field of communication, and relates to a communication method of an enhanced high-efficiency short-spread-differential chaotic keying (VHE-SR-DCSK) communication system.
Background
Chaotic communication draws wide attention in the aspects of low power consumption and low complexity, and the good multipath fading resistance and autocorrelation and cross-correlation characteristics enable the chaotic communication to be widely applied to the field of wireless communication. Meanwhile, the chaotic signal has good aperiodic and wide spectrum characteristics similar to random noise, meets the special requirements of secret communication, and can be used for hiding useful information. Therefore, the research of the chaotic communication system has practical significance. At present, most chaotic communication systems applied to the field of digital communication have certain defects. For example, a Differential Chaotic Shift Keying (DCSK) system adopts a transmission-reference mode, and transmits both a reference carrier and a signal carrying information to a receiving party without channel estimation and spreading code synchronization, thereby greatly simplifying the system structure and reducing the design cost of the system. However, the transmission rate of the system is low because transmitting a reference signal that does not carry any data takes half the time of the system.
The transmitting end of a related delay shift keying (CDSK) system transmits the chaos reference signal and the modulated signal together, and because the receiving end does not need spread spectrum code synchronization in the traditional spread spectrum communication and only needs to perform delay related operation on the received signal, the data transmission rate of the CDSK system is 2 times that of the DCSK system, and simultaneously, the approximate orthogonality among different chaos sequences is utilized, so that the information transmitted among each frame has no correlation, the transmission signal of the CDSK is more difficult to intercept, and the information transmission safety is also improved to a certain extent.
From the beginning of the 20 th century, scientists and scholars studying chaotic communication at home and abroad have conducted deep exploration and research on how to better apply chaotic communication technology to the field of wireless communication.
CN106341221A is a repeated correlation delay keying method for improving performance of a wireless chaotic communication system, in which a switch is added to a correlated delay keying CDSK transmitting end, that is, the transmitting end of the repeated correlation delay keying R-CDSK continuously transmits a chaotic modulation signal corresponding to the same information, a differential chaotic modulation signal thereof, and a reference chaotic signal common to both in two symbol periods. The method fully utilizes the time diversity of the wireless channel, reduces the bit error rate of transmission by repeatedly sending the chaos modulation signals which are mutually differential, thereby effectively improving the reliability of the CDSK. In addition, because the R-CDSK transmits the differential modulation symbols carrying information, the safety communication performance of the system is improved. Compared with the existing scheme, the invention realizes the information transmission which is more reliable than CDSK and safer than DCSK with lower complexity.
Disclosure of Invention
The present invention is directed to solving the above problems of the prior art. The method is characterized in that the defects of low data rate and low energy efficiency of a classical short-spread differential chaos keying (SR-DCSK) modulation technology are improved in a related mode, a reference signal with the length of R is adopted at a transmitting end and is transmitted in the same first frame duration as the SR-DCSK, an orthogonal signal base is used for transmitting the addition of 2N orthogonal information signals in the second frame duration, and a data signal and the corresponding reference signal are related in a receiver to recover the information signal. A communication method of an enhanced high-efficiency short-parameter DCSK chaotic communication system is provided. The technical scheme of the invention is as follows:
a communication method of an enhanced high-efficiency short-parameter DCSK chaotic communication system comprises the following steps:
step 1: generating a chaotic reference signal by using a second-order Chebyshev polynomial function;
step 2: the Hilbert transform and WALSH are used for generating an orthogonal signal set to modulate an information signal and a transmission signal;
and step 3: and (3) carrying out channel transmission by adopting a multipath Rayleigh fading channel:
and 4, step 4: the receiving end correlates the received signal after delaying it, and then multiplies it with the respective WALSH code and restores the information signal by the decision threshold.
Further, the step 1: the method for generating the chaotic reference signal by using the second-order Chebyshev polynomial function specifically comprises the following steps:
step 1.1: generating an initial chaotic sequence: generation of chaotic sequence y using a second order Chebyshev polynomial function i,k Then useSign function sgn (. gamma.) is normalized by y i,k Making the energy of the signal constant to obtain a chaotic sequence x i,k ：
Step 1.2: the chaotic sequence generated in step 1.1 is processed
With its signal after Hilbert transform
The method is divided into two groups, Hilbert transform is used for distinguishing chaotic signals, and strict orthogonality between two chaotic sequences is guaranteed;
step 1.3: according to the number of users N, Walsh codes are used to define signals in the same group, i.e., when the number of users N is assumed to be 2, two second-order Walsh codes are required to distinguish signals in the group.
Further, the step 2 of modulating the information signal and transmitting the signal specifically includes:
step 2.1: transmitting a reference signal: generating a reference signal with a sequence length of R by the chaotic signal generator, and transmitting the reference signal in a reference time slot;
step 2.2: copying a reference signal: copying the reference signal for P times to obtain a chaotic signal with the sequence length of beta; β ═ PR;
step 2.3: the signal obtained after copying and the Hilbert transform thereof are respectively modulated by N information bits, and then the two paths of signals are added and transmitted as information signals, so that 2N information bits can be transmitted in one time slot.
Further, the step 3: the method for channel transmission by using a multipath Rayleigh fading channel model specifically comprises the following steps:
in the multipath Rayleigh fading channel model, the gain of each channel is set to be alpha l L is 1,2,3, …, L and they all obey a Rayleigh distribution with a delay of τ per channel l 1,2,3, …, L, signals transmitted by all channelsAfter the addition, the signal is also subjected to additive white Gaussian noise delta k (t), the received signal after passing through a multipath rayleigh fading channel is expressed as:
where L denotes the ith path and L denotes the maximum number of paths of the channel.
Further, the step 4: the receiving end demodulates the received signal and restores the information signal, and the method specifically includes:
step 4.1: processing the received signal: assuming that the signal is only interfered by additive white gaussian noise during transmission, the expression of the received signal can be expressed as: r is i,k ＝s i,k +δ i,k ，r i Representing signals received by the system at the receiving end, s i Representing signals, delta, transmitted by the transmitting end of the system i Representing a mean of 0 and a variance of N 0 Additive white Gaussian noise of/2;
step 4.2: a received signal r i,k After delaying R, correlating the reference signal with P continuous information signal samples of the frame to obtain the length of each information signal sample as R;
step 4.3: multiplying the information signal by the respective WALSH code to obtain the respective corresponding information bit;
step 4.4: and adding the P independent correlation values to obtain a decision variable, and comparing the symbol of the decision variable with a zero threshold value to recover the original signal bit.
Further, the received signal satisfies the mean value E [ n ] i,k ]0, variance Var [ n [ ] i,k ]＝N 0 /2。
The pth partial correlation for the pth transmitted information bit can be expressed as:
wherein
Is the extracted reference signal, n i,p,k For the i-th noise interference experienced in the P-th information signal sample, n i-R,k Representing AWGN noise, w, received by the reference signal during transmission i,u Is the walsh code corresponding to the u-th information bit. r is i,p,k P-th information bit, r, representing the ith received signal in k slots i-R,k Representing the signal, alpha, obtained after a delay R of the received signal l And the attenuation coefficient of the multipath Rayleigh channel on the ith path is shown.
Further, the instantaneous BER formula of VHE-SR-DCSK becomes:
where P denotes the number of copies of the reference signal, N denotes the number of users,
represents the ratio of each binary bit energy to the noise energy spectral density, erfc (x) represents the complementary error function, which can be defined as:
the invention has the following advantages and beneficial effects:
the invention carries out relevant improvement on the defects of low data rate and low energy efficiency of the classic short-spread differential chaos keying (SR-DCSK) modulation technology, a reference signal with the length of R is adopted at a transmitting end to be transmitted in the same first frame duration as the SR-DCSK, an orthogonal signal base is used for transmitting the addition of 2N orthogonal information signals during the second frame duration, and a data signal and the corresponding reference signal are correlated at a receiver to recover the information signal.
Compared with an SR-DCSK system, the enhanced high-efficiency short-parameter DCSK chaotic communication system provided by the invention not only has remarkable improvement on energy efficiency and rate, but also obtains better BER performance.
Drawings
FIG. 1 is a schematic diagram of an orthogonal chaotic base signal set according to a preferred embodiment of the present invention;
FIG. 2 is a diagram of a transmitting end structure of the VHE-SR-DCSK system of the invention;
FIG. 3 is a diagram of a receiving end structure of the VHE-SR-DCSK system of the invention;
FIG. 4 is a diagram of the transmission structure of RFC channel of VHE-SR-DCSK system of the present invention;
FIG. 5 is a graph comparing theoretical BER with simulation results for AWGN channels in accordance with the present invention;
FIG. 6 is a graph of the BER performance variation for different numbers of users in the AWGN channel;
FIG. 7 different E's under AWGN channel in accordance with the invention b /N 0 Under the condition, a curve graph of the change relation of the system BER performance and the sequence length R;
FIG. 8 is a graph comparing the BER performance of the system of the present invention under AWGN channel with that of DCSK, SR-DCSK under AWGN channel;
FIG. 9 is a diagram comparing the theoretical BER of the system of the present invention under the multi-path RFC channel with the simulation result;
FIG. 10 is a diagram comparing BER performance of the system of the present invention under multipath RFC channel with that of DCSK, SR-DCSK system.
Detailed Description
The technical solutions in the embodiments of the present invention will be described in detail and clearly with reference to the accompanying drawings. The described embodiments are only some of the embodiments of the present invention.
The technical scheme for solving the technical problems is as follows:
the following detailed description of the embodiments of the invention will be made with reference to the accompanying drawings. Strictly speaking, the finite-duration chaotic sequences are not perfectly orthogonal to each other. In order to reduce the error rate and prevent the influence of intersymbol interference on the error rate, the invention designs an orthogonal chaotic base signal set, and combines the Hilbert transform technology and the WALSH code to realize strict orthogonality among signals.
Firstly, a chaos sequence is generated and paired through a second-order Chebyshev polynomial function by the systemNormalizing the data by a sign function to obtain x i (t) generating a chaotic sequence by Hilbert transform
X is to be i (t) and
it is divided into two groups. The Walsh codes are then used to define the signals within the same group based on the number of users N. That is, when the number N of users is 2, two second-order WALSH codes are required to distinguish the intra-group signals. Specific grouping procedure as shown in fig. 1, the signals between the first and second groups are orthogonal, and the internal signals of each group are also orthogonal. Meanwhile, the division method can be easily expanded to a function set with a larger size through a higher-order WALSH code.
Walsh codes, which are often used to cancel interference between signals due to their good orthogonality, are usually formed by Hadamard matrices, and are generated as follows:
generating end structure of VHE-SR-DCSK system as shown in fig. 2, in order to improve data rate, energy efficiency and BER performance, the system uses the orthogonal chaotic base signal set mentioned in fig. 1 to prevent BER performance of VHE-SR-DCSK from being deteriorated due to inter-symbol interference. In a VHE-SR-DCSK system, a chaotic sequence with the sequence length of R is generated at first and is transmitted in a reference time slot. Then, the reference signal is copied P times to obtain a chaotic signal with a sequence length β (β ═ PR). And modulating the copied chaotic sequence and the sequence subjected to Hilbert transform by N information bits respectively, and finally adding the chaotic sequence and the sequence for transmission.
The signal transmitted by the generating end can be expressed as:
wherein x i,k Representing the reference signal, R is the sequence length of the reference signal, b j And b N+j Representing information bits, P representing the number of copies of the reference signal, w i,j Is an information bit b j And b N+j The corresponding Walsh code.
Fig. 3 is a system block diagram of a receiving end of a VHE-SR-DCSK system, which uses non-coherent demodulation to decode information bits. The u (1 ≦ u ≦ N) th signal bit is taken as an example in the demodulation process to better illustrate the decoding process of all information bits. . To demodulate the u-th information bit, r needs to be demodulated first i,k The delay sequence length R. Next, the reference signal is correlated with P consecutive information signal samples of the frame, each information signal sample having a length R. Multiplying the P independent correlation values by the information bit b u Corresponding Walsh code w i,u . Finally, the P independent correlation values are added to obtain a decision variable, and the information bit b is recovered by comparing the decision variable with a zero threshold value u . Other information bits of the first N information bits may also be extracted using the same method. The reference signal in the decoding process is replaced by the Hilbert transform, and the same decoding operation is performed, so that the next N information bits can be decoded. Finally, all information bits are estimated using a sign function.
During the actual transmission, s i,k Under the influence of obstacles such as buildings, trees and the like, the VHE-SR-DCSK system reaches a receiving end through a plurality of paths such as reflection, refraction, diffraction and the like, and in order to enable the derivation result to be closer to the error rate in actual transmission, a multipath RFC model shown in figure 4 is adopted to analyze the performance of the VHE-SR-DCSK system.
Thus, the received signal r i,k Can be expressed as:
wherein alpha is l Representing the channel coefficient, τ l Time delay of the L-th path, L tableIndicates the number of paths, and n i,k Is additive white Gaussian noise, satisfies the mean value of E [ n ] i,k ]0, variance Var [ n [ ] i,k ]＝N 0 /2。
The pth partial correlation for the pth transmitted information bit can be expressed as:
wherein
Is the extracted reference signal, n i,p,k For the i-th noise interference experienced in the P-th information signal sample, n i-R,k Representing the AWGN noise, w, received by the reference signal during transmission i,u Is the walsh code corresponding to the u-th information bit.
From the above equation, P consecutive information signal samples need to be calculated to obtain P independent correlation values, so the above equation needs to be rewritten as:
the decision variable expression in the partial correlation drive-in formula can be rewritten as:
when the length R of the reference signal is large, the following approximate expression is used:
by the above expressionCan be substituted by Z u,k Further simplification and calculation:
Z u,k ＝X+Y+H
wherein:
all decision variables for 2N information bits are equal, so for simplicity of analysis, the following section takes the u-th information bit as an example.
Z u,k The calculation in (1) follows a gaussian distribution based on the central limit theorem. Therefore, the BER expression for the u-th information bit can be expressed as:
for the u-th (1. ltoreq. u. ltoreq.N) information bit in the k-th frame, Z u,k Can be calculated as:
where Eb is the average bit energy, E [ ] represents the desired operator:
depending on the nature of the statistical variance, the variance of the sum of the individual terms X, Y, H can also be obtained by summing the variances of the individual terms, where Var [. multidot.]Representing a variance operator. Thus, it is possible to provideVariance Z u,k By calculating:
Var[Z u,k ]＝Var[X]+Var[Y]+Var[H]
wherein:
Var[X]＝0
substituting the variance into a variance expression Z u,k Can be written as:
the instantaneous BER formula of the available VHE-SR-DCSK becomes:
where erfc (, denotes the complementary error function, which can be defined as:
the invention calculates the Energy Efficiency (EE) and the Bit Rate (BR) of the VHE-SR-DCSK system, and analyzes the comparison of the VHE-SR-DCSK with the traditional DCSK and SR-DCSK. EE is calculated from the ratio of the total transmitted bit energy to the total transmitted energy, and BR can be defined as the number of bits transmitted per unit time. The table below specifically shows EE and BR for these three systems. From the table, we can easily find that both EE and BR of VHE-SR-DCSK are higher than DCSK and SR-DCSK, therefore, the result shows that VHE-SR-DCSK is more suitable for actual chaotic communication.
The invention carries out numerical simulation on AWGN and multipath RFC channels, and emphatically verifies the accuracy of the theoretical BER expression derived by the reasoning in the above. We also compared BER performance to existing conventional DCSK and SR-DCSK. The parameters such as the number of users N, the length R of the reference signal and the like are mainly analyzed.
In fig. 5, a simulation curve is plotted and compared with a BER curve obtained by theoretical analysis, and the theoretical value of BER is highly consistent with the simulated value for [ R, P, N ], [128,2,4], [256,2,4], thereby proving the correctness of the BER theoretical formula. Further observation of this graph shows that as R increases, the BER decreases significantly, resulting in an increase in the interference between chaotic signal and noise as R increases.
Figure 6 shows the BER performance at different values of N. In fig. 6, it can be clearly seen that BER performance deteriorates as N increases, while the values of R and P are determined. This can be interpreted as the interference between the information signal and the noise increases with increasing N, resulting in a deterioration of BER performance.
The BER versus R value for Eb/N0 at 10dB, 15dB and 18dB is shown in fig. 7. It is clear that the BER performance of VHE-SR-DCSK deteriorates with increasing R. Consistent with the results depicted in fig. 5, the reason for this phenomenon is the same as explained in fig. 6. There is therefore a trade-off between BER performance and data rate, depending on the specific requirements of the user.
In FIG. 8, BER performance curves for DCSK, SR-DCSK and VHE-SR-DCSK systems are plotted under AWGN channel. For fair comparison, here the same spreading factor β is set, we further set [ R, P ] ═ 128,2] in SR-DCSK and VHE-SR-DCSK systems. As is clear from fig. 8, the BER performance of VHE-SR-DCSK is slightly better than that of SR-DCSK under the same conditions, and the BER performance of these two systems is much better than that of DCSK system under the same conditions. However, the bit rate of the VHE-SR-DCSK system is significantly faster than the DCSK and SR-DCSK systems in terms of transmission rate.
FIG. 9 shows the theoretical results of BER expression and multipathAnd (5) simulation results under different conditions under the RFC channel. The following table shows simulation parameters in each specific case, where R represents the length of the reference signal, P represents the number of repetitions of the chaotic sequence, N represents the number of transmission bits, L represents the number of paths, and E [ α [ ] 2 l ]Denotes the average power gain, τ, of the l-th path l Representing the time delay, alpha l The path gain is indicated.
As is clear from fig. 9, the theoretical value of BER is consistent with the simulation results under different conditions of multipath RFC channels, which proves the validity of the theoretical BER expression. We also note that BER performance is better when the average power gain per channel is equal.
BER performance curves of DCSK, SR-DCSK and VHE-SR-DCSK systems under a three-path RFC channel are shown in FIG. 10. The delay of the 3-path RFC channel is tau 1 ＝0,τ 2 ＝1,τ 3 2 and all paths have equal average power gain. To demonstrate comparative fairness, we set β -256 in DCSK systems, R-128 and P-2 in SR-DCSK and VHE-SR-DCSK systems to ensure spreading factors are equal. As can be seen from fig. 10, the BER performance of the VHE-SR-DCSK system is the best under the same channel environment compared to the DCSK and SR-DCSK systems.
The invention introduces and analyzes a very efficient SR-DCSK modulation and demodulation system to meet the requirements of modern communication, and the system improves the data rate and simultaneously maintains the advantages of the traditional SR-DCSK system. VHE-SR-DCSK has the same frame structure as SR-DCSK, while we design a set of orthogonal chaotic signals, expanding the transmitted bits by using WALSH codes and hilbert transforms. These operations are intended to improve data rate and BER performance. A general theoretical BER expression over a multipath RFC channel is derived and simplified to accommodate the AWGN channel environment. The results obtained by computer simulation show that the BER performance of VHE-SR-DCSK is better than that of traditional DCSK and SR-DCSK not only in AWGN but also in multipath RFC channels.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The above examples are to be construed as merely illustrative and not limitative of the remainder of the disclosure. After reading the description of the invention, the skilled person can make various changes or modifications to the invention, and these equivalent changes and modifications also fall into the scope of the invention defined by the claims.
Claims (7)
1. A communication method of an enhanced high-efficiency short-parameter DCSK chaotic communication system is characterized by comprising the following steps:
step 1: generating a chaotic reference signal by using a second-order Chebyshev polynomial function;
step 2: hilbert transform and WALSH are used for generating an orthogonal signal set to modulate an information signal and a transmission signal;
and step 3: and (3) carrying out channel transmission by adopting a multipath Rayleigh fading channel:
and 4, step 4: the receiving end correlates the received signal after delaying, multiplies the signal by the respective WALSH code, and restores the information signal through the decision threshold.
2. The communication method of the enhanced high-efficiency short-parameter DCSK chaotic communication system as claimed in claim 1, wherein the step 1: the method for generating the chaotic reference signal by using the second-order Chebyshev polynomial function specifically comprises the following steps:
step 1.1: generating an initial chaotic sequence: generation of chaotic sequence y using a second order Chebyshev polynomial function i,k Then normalized y using sign function sgn () i,k Making the energy of the signal constant to obtain a chaotic sequence x i,k ：
Step 1.2: the chaotic sequence generated in step 1.1 is processed
With its signal after Hilbert transform
The method is divided into two groups, Hilbert transform is used for distinguishing chaotic signals, and strict orthogonality between two chaotic sequences is also ensured;
step 1.3: according to the number of users N, Walsh codes are used to define signals in the same group, i.e., when the number of users N is assumed to be 2, two second-order Walsh codes are required to distinguish signals in the group.
3. The communication method of the enhanced high-efficiency short-parameter DCSK chaotic communication system according to claim 1, wherein the step 2 of modulating the information signal and transmitting the signal specifically comprises:
step 2.1: transmitting a reference signal: generating a reference signal with a sequence length of R by the chaotic signal generator, and transmitting the reference signal in a reference time slot;
step 2.2: copying a reference signal: copying the reference signal for P times to obtain a chaotic signal with the sequence length of beta; β ═ PR;
step 2.3: the signal obtained after copying and the Hilbert transform thereof are respectively modulated by N information bits, and then the two paths of signals are added and transmitted as information signals, so that 2N information bits can be transmitted in one time slot.
4. The communication method of the enhanced high-efficiency short-parameter DCSK chaotic communication system as claimed in claim 1, wherein the step 3: the method for channel transmission by using a multipath rayleigh fading channel specifically comprises the following steps:
in the multipath Rayleigh fading channel model, the gain of each channel is set to be alpha l L1, 2,3, …, L and they all obey a Rayleigh distribution with a delay of τ per channel l L1, 2,3, …, L, the signals transmitted by all channels are added and then subjected to additive white gaussian noise δ k (t), the received signal after passing through a multipath rayleigh fading channel is expressed as:
where L denotes the ith path and L denotes the maximum number of paths of the channel.
5. The communication method of the enhanced high-efficiency short-parameter DCSK chaotic communication system as claimed in claim 1, wherein the step 4: the receiving end demodulates the received signal and restores the information signal, and the method specifically includes:
step 4.1: processing the received signal: assuming that the signal is only interfered by additive white gaussian noise during transmission, the expression of the received signal can be expressed as: r is i,k ＝s i,k +δ i,k ，r i Representing the signal, s, received by the system at the receiving end i Indicating the signal, delta, sent by the transmitting end of the system i Representing a mean of 0 and a variance of N 0 Additive white Gaussian noise of/2;
step 4.2: a received signal r i,k After delaying R, correlating the reference signal with P continuous information signal samples of the frame to obtain the length of each information signal sample as R;
step 4.3: multiplying the information signal by the respective WALSH code to obtain the respective corresponding information bit;
step 4.4: and adding the P independent correlation values to obtain a decision variable, and comparing the symbol of the decision variable with a zero threshold value to recover the original signal bit.
6. The communication method of the enhanced high-efficiency short-parameter DCSK chaotic communication system as claimed in claim 4, wherein the received signal satisfies the mean value E [ n ] i,k ]0, variance Var [ n [ ] i,k ]＝N 0 /2。
The pth partial correlation for the pth transmitted information bit can be expressed as:
wherein
Is the extracted reference signal, n i,p,k For the i-th noise interference experienced in the P-th information signal sample, n i-R,k Representing AWGN noise, w, received by the reference signal during transmission i,u Is the Walsh code corresponding to the u-th information bit, r i,p,k P-th information bit, r, representing the ith received signal in k slots i-R,k Representing the signal, alpha, obtained after a delay R of the received signal l Representing the fading coefficients of the multipath rayleigh channel on the ith path.
7. The communication method of the enhanced high-efficiency short-parameter DCSK chaotic communication system as claimed in claim 6, wherein the instantaneous BER formula of the VHE-SR-DCSK is changed to:
where P denotes the number of copies of the reference signal, N denotes the number of users,
representing the ratio of the energy per binary bit to the spectral density of the noise energy, erfc (×) represents a complementary error function, which can be defined as:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210210354.3A CN114826848A (en) | 2022-03-04 | 2022-03-04 | Communication method of enhanced high-efficiency short-parameter DCSK chaotic communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210210354.3A CN114826848A (en) | 2022-03-04 | 2022-03-04 | Communication method of enhanced high-efficiency short-parameter DCSK chaotic communication system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114826848A true CN114826848A (en) | 2022-07-29 |
Family
ID=82529153
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210210354.3A Pending CN114826848A (en) | 2022-03-04 | 2022-03-04 | Communication method of enhanced high-efficiency short-parameter DCSK chaotic communication system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114826848A (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106452719A (en) * | 2016-07-15 | 2017-02-22 | 浙江工业大学 | Safety communication method based on combination of artificial Rayleigh fading and adaptive modulation |
| CN107872412A (en) * | 2016-09-27 | 2018-04-03 | 重庆邮电大学 | A kind of energy-efficient difference chaotic communication system |
| CN109412988A (en) * | 2018-11-01 | 2019-03-01 | 重庆邮电大学 | A kind of orthogonal multi-user's chaos shift keying communication plan |
| CN110417695A (en) * | 2019-08-07 | 2019-11-05 | 厦门大学 | The reference diversity algorithm for design of multilevel code shift differential chaos offset keying system |
| CN111817993A (en) * | 2020-06-09 | 2020-10-23 | 重庆邮电大学 | Improved short reference correlation delay shift keying communication scheme |
| CN111988128A (en) * | 2019-05-21 | 2020-11-24 | 重庆邮电大学 | Multi-input single-output multi-user orthogonal efficient DCSK communication scheme |
| CN111988251A (en) * | 2019-05-21 | 2020-11-24 | 重庆邮电大学 | Improved orthogonal multi-user differential chaotic communication system |
| CN113890805A (en) * | 2021-11-18 | 2022-01-04 | 重庆邮电大学 | Multi-user multi-carrier CDSK chaotic communication method and system with high transmission rate |
| CN114039825A (en) * | 2021-11-15 | 2022-02-11 | 南京铁道职业技术学院 | SIMO-HPO-CDSK communication method based on Rayleigh fading channel |
-
2022
- 2022-03-04 CN CN202210210354.3A patent/CN114826848A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106452719A (en) * | 2016-07-15 | 2017-02-22 | 浙江工业大学 | Safety communication method based on combination of artificial Rayleigh fading and adaptive modulation |
| CN107872412A (en) * | 2016-09-27 | 2018-04-03 | 重庆邮电大学 | A kind of energy-efficient difference chaotic communication system |
| CN109412988A (en) * | 2018-11-01 | 2019-03-01 | 重庆邮电大学 | A kind of orthogonal multi-user's chaos shift keying communication plan |
| CN111988128A (en) * | 2019-05-21 | 2020-11-24 | 重庆邮电大学 | Multi-input single-output multi-user orthogonal efficient DCSK communication scheme |
| CN111988251A (en) * | 2019-05-21 | 2020-11-24 | 重庆邮电大学 | Improved orthogonal multi-user differential chaotic communication system |
| CN110417695A (en) * | 2019-08-07 | 2019-11-05 | 厦门大学 | The reference diversity algorithm for design of multilevel code shift differential chaos offset keying system |
| CN111817993A (en) * | 2020-06-09 | 2020-10-23 | 重庆邮电大学 | Improved short reference correlation delay shift keying communication scheme |
| CN114039825A (en) * | 2021-11-15 | 2022-02-11 | 南京铁道职业技术学院 | SIMO-HPO-CDSK communication method based on Rayleigh fading channel |
| CN113890805A (en) * | 2021-11-18 | 2022-01-04 | 重庆邮电大学 | Multi-user multi-carrier CDSK chaotic communication method and system with high transmission rate |
Non-Patent Citations (3)
| Title |
|---|
| FADIA TALEB: "\"Very high efficiency Differential Chaos Shift Keying system with Walsh Hadamard codes\"", 《IEEE 2016 5TH ICMCS》 * |
| GEORGES KADDOUM: "\"Design of a short reference noncoherent chaos-Based communication systems\"", 《IEEE TRANSACTIONS ON COMMUNICATION》 * |
| 张刚，许嘉平，张天骐: ""基于希尔伯特变换的多用户DCSK通信系统性能分析"", 《电子与信息学报》 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2134230C (en) | Method and apparatus for coherent communication in a spread-spectrum communication system | |
| CN112073352B (en) | Index modulation-based single-carrier high-speed spread spectrum underwater acoustic communication method | |
| CN101138212B (en) | Method for the flexible demodulation of estimated complex symbols | |
| CN113890805B (en) | Multi-user multi-carrier CDSK chaotic communication method and system with high transmission rate | |
| CN111988251A (en) | Improved orthogonal multi-user differential chaotic communication system | |
| CN101467380A (en) | Method and apparatus for estimating noise varience | |
| Faisal et al. | Simulation based Performance Analysis of MC-CDMA and CDMA over Rayleigh fading channel | |
| Smida et al. | MC-CDMA performance evaluation over a multipath fading channel using the characteristic function method | |
| CN114826848A (en) | Communication method of enhanced high-efficiency short-parameter DCSK chaotic communication system | |
| CN111988128A (en) | Multi-input single-output multi-user orthogonal efficient DCSK communication scheme | |
| CN103684687B (en) | Mine roadway uplink MC-CDMA wireless transmission cooperation method | |
| CN114666191B (en) | Communication method of orthogonal multi-user shift noise reduction DCSK chaotic communication system | |
| CN112822133A (en) | Multi-user orthogonal frequency division multiplexing differential chaos keying communication method | |
| STROM et al. | Iterative demodulation and channel estimation of orthogonal signaling formats in asynchronous DS-CDMA systems | |
| Berber et al. | Theoretical modeling and simulation of a chaos-based physical layer for WSNS | |
| Aswathy | Performance Analysis of Code Hopping Multiple Access using Orthogonal Complementary Codes under Rician Fading Channels | |
| Zhang et al. | Multi-user high rate security differential chaos shift keying | |
| Elnoubi et al. | Effect of overlapping between successive carriers of multicarrier CDMA on the performance in a multipath fading channel | |
| CN114189414B (en) | Multi-user efficient anti-interference CDSK chaotic communication system and method | |
| Frikel et al. | Channel identification using chaos for an uplink/downlink multicarrier code division multiple access system | |
| Chen et al. | Capacity of space–time block-coded CDMA systems: Comparison of unitary and complementary codes | |
| CN116405055B (en) | Spread spectrum communication method, system and related device | |
| Vinod et al. | Compressed sensing algorithm for pattern division multiple access (pdma) in 5g radio networks | |
| Tian et al. | Code Index Modulation CSK Spread Spectrum Underwater Acoustic Communications | |
| Yu et al. | Blind separation of ds-cdma signals with ica method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |