CN104468451B - A kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication - Google Patents

A kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication Download PDF

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CN104468451B
CN104468451B CN201410751477.3A CN201410751477A CN104468451B CN 104468451 B CN104468451 B CN 104468451B CN 201410751477 A CN201410751477 A CN 201410751477A CN 104468451 B CN104468451 B CN 104468451B
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ccsk
mccsk
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CN104468451A (en
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郇浩
常诚
陶然
谭维凤
张竞文
徐宇轩
陈星逸
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Beijing Institute of Technology BIT
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • H04L27/2626Arrangements specific to the transmitter only
    • H04L27/2627Modulators
    • H04L27/2628Inverse Fourier transform modulators, e.g. inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00Modulated-carrier systems
    • H04L27/26Systems using multi-frequency codes
    • H04L27/2601Multicarrier modulation systems
    • H04L27/2647Arrangements specific to the receiver only
    • H04L27/2649Demodulators
    • H04L27/265Fourier transform demodulators, e.g. fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators

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  • Computer Networks & Wireless Communication (AREA)
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Abstract

The present invention relates to a kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication, belong to radio digital communication field.Comprise the following steps:Transmitting terminal generation normalization frequency domain basic function, and by normalized frequency domain basic function progress inverse Fourier transform generation Temporal Basis Function, MCCSK subsymbols are then generated according to Temporal Basis Function, and transmitting after data modulation is carried out using subsymbol;Then receiving terminal generation carries out MCCSK data demodulation according to Temporal Basis Function, obtains demodulating data corresponding to the Temporal Basis Function of transmitting terminal.The present invention lifts the diversity of modulation symbol using the method for number of combinations, combination is overlapped to the symbol that basic function cyclic shift is generated, generate more escape characters, the symbol combination for therefrom selecting average minimum mark space larger is modulated, demodulating end multistage demodulation by way of demodulating data, both the quantity of unit waveform carrying information had been added, again bit-error rate penalty has been effectively controlled.

Description

A kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication
Technical field
The present invention relates to a kind of modulation-demo-demodulation method, more particularly to a kind of multiple stage circulation shift key based on transform-domain communication Modulation-demo-demodulation method is controlled, belongs to radio digital communication field.
Background technology
Transform domain communication system (Transform Domain Communication System, TDCS) is that one kind is based on Spectrum environment is cognitive, and the jamproof new technology that communicates is realized by transform-domain processing and spread spectrum, because resisting for its uniqueness is dry Disturb mode and by lot of domestic and foreign focus of attention and research.Different from the anti-interference method such as traditional Direct-Spread, frequency hopping, it is not It is passively to adapt to spectrum environment again, but actively by spectrum environment sensing, construction is mutual with interference in transmission band Orthogonal basic modulation waveform, reaches the purpose for making full use of spectrum signature to realize communication under strong interference environment.In addition, Due to the introducing of CCSK (Cyclic Code Shift Keying, cyclic shift keying) modulation systems and random phase so that System has low detection/low interception capability (Low Probability of Detect/Low Probability of Intercept, LPD/LPI) and multiple access capabilities.During TDCS basic thought is the article delivered by German in 1988 Propose, he devises a kind of transmitting terminal and receiving terminal using change for not enough present in Direct-Spread and frequency-hopping system The system for changing domain processing, it is proposed that the concept of transform domain Waveform Design.1991, the Andren of Harris companies applied for one The technical patent similar with German, realizes that LPI communicates with this, but without the specific theoretical and implementation of offer.Until 1997, USAF entered the extremely strong electronic interferences problem faced when enemy territorial sky performs task for military aircraft, uses What Andren was proposed sample to electromagnetic environment, the transceiver architecture of waveform generation and German are based on spectrum environment sampled result The thought of modulation basic function is produced, this is also TDCS blank.Because this technology has great military significance, in 2001 U.S. Department of Defense is on also there is the introduction for TDCS development situations in the report of electronic warfare development plan. V.Chakravarthy proposes to regard TDCS as cognitive radio (Cognitive Radio, CR) transceiver on WCNC2005 Alternative.Hereafter, research TDCS upsurge has been started both at home and abroad.It is external main with USAF technical college and air force's skill Art research department is representative, and the domestic research for TDCS is still in theory stage, focuses primarily upon its interference free performance and biography Unite Direct-Spread, the contrast of frequency-hopping method and with OFDM (Orthogonal Frequency Division Multiplexing, OFDM), frequency spectrum interaction etc. other technologies combination.The method for improving TDCS system spectral efficiencies is mainly divided For two kinds:More reasonably system architecture and more efficient modulation-demo-demodulation method.Hu etc. devises a kind of orthogonal transform domain communication system System, the characteristics of having same frequency spectrum using the real and imaginary parts of complex signal distinguishes carrying information, demodulates, reach respectively in receiving terminal The purpose of spectrum efficiency is improved, but hoisting power is limited.They also proposed a kind of transform-domain communication clustered based on frequency spectrum System, spectrum interposition is grouped, respectively carrying information, exchanges the lifting of spectrum efficiency for the loss of bit error rate performance, but exist The problem of penalty is serious under the mutual interference of symbol and strong interference environment.Budiarjo etc. proposes a kind of combination PSK's and CCSK Two-dimensional modulation system architecture, the problem of making waveform carry more information, but there are mutual interference and cumulative errors simultaneously.Galias Etc. a kind of modulator approach of orthogonal chaos offset keying is proposed, the front half section of waveform is transmitted into reference waveform, second half section transmission Modulation data, although systematic function gets a promotion, but efficiency halves.Fumat etc. proposes a kind of method of multi-dimensional modulation and carried Raising frequency spectrum efficiency, although used the method for number of combinations to carry out subsymbol extension, but article all uses the subsymbol of extension In modulation so that symbol and data can not map one by one, add the bit error rate of demodulating end.Therefore, seek a kind of more efficient Modulation-demo-demodulation method becomes a major issue for improving spectrum efficiency.
The content of the invention
The invention aims to solve the problem of existing CCSK methods information transfer efficiency is relatively low, propose based on conversion The multiple stage circulation shift keying modulation demodulation method of field communication.
The present invention is realized based on following thought:When usable spectrum hole exceedes certain proportion, CCSK subsymbols can It is considered quasi-orthogonal, therefore auto-correlation correlation peak height and sharp during correlation demodulation, cross-correlation peak tends towards stability, but in demodulation It is that a kind of of modulation demodulation resource is wasted that a relevant peaks demodulation is used only in the correlation length of end.The method of number of combinations can be effective The diversity of difference is lifted, therefore combination, the more extensions of generation can be overlapped to the symbol that basic function cyclic shift is generated Symbol, the symbol for therefrom selecting average minimum mark space larger is modulated, in demodulating end by way of multistage demodulation solution Adjusting data, had both added the information content of unit waveform carrying, and effectively controlled bit-error rate penalty.
The purpose of the present invention is achieved through the following technical solutions:
Transform domain communication system belongs to spread spectrum system, and there is also information transfer speed while possessing good antijamming capability The problem of rate is relatively low.The relativity of information of each symbol should be improved as far as possible by improving efficiency of transmission, therefore can be by the side of superposition Formula makes unit waveform carry more information content, and the information of superposition is obtained using multistage demodulation in receiving terminal.So both ensure The increase of transmission rate, and signal and the orthogonality disturbed in spectrum environment are not destroyed, maintain interference free performance.Set accordingly MCCSK modulation demodulation systems are counted, and corresponding TDCS communication systems are constructed with this.
A kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication, comprises the following steps:
Step 1, transmitting terminal generation normalization frequency domain basic function;
By energy detection technique, spectrum environment in service bandwidth is sampled and estimated, generation Frequency and Amplitude spectrum.Will Element in Frequency and Amplitude spectrum is compared with interference threshold thresholding one by one, and the corresponding frequency spectrum disposal of element more than thresholding is 0, is represented The frequency spectrum is interfered;The corresponding frequency spectrum disposal of element not less than thresholding is 1, and expression is not interfered or disturbed not tight The frequency spectrum (spectrum interposition) of weight, generates spectrum amplitude matrix.Pass through linear shift register generation and spectrum amplitude matrix length Identical random phase, and it is multiplied to frequency domain basic function with spectrum amplitude matrix dot.To ensure that transmission signal energy is unified, to frequency Domain basic function carries out energy normalized according to spectrum interposition number, obtains normalized frequency domain basic function;
Step 2, normalized frequency domain basic function is carried out inverse Fourier transform generation Temporal Basis Function by transmitting terminal;
Normalized frequency domain basic function is subjected to inverse Fourier transform, the Temporal Basis Function of identical points is obtained;By time domain Basic function is stored, for generating MCCSK subsymbol and carrying out MCCSK modulation;
Step 3, transmitting terminal generates MCCSK subsymbols according to Temporal Basis Function, and is carried out using subsymbol after data modulation Transmitting;
M ranks circulative shift operation is carried out to Temporal Basis Function (successively that signal is overall by stepping of Δ t=T/M in time domain Translate backward, and wave tail mended to shift signal front portion beyond the part of original signal length, T is signal duration), it is raw Into M CCSK subsymbol.If MCCSK subsymbol stacking fold is ns, then can generate Individual extension subsymbol, order M is modulated according to MCCSKs(And be 2 power), from newly-generated extension subsymbol Choose the larger M of average minimum mark spacesThe subsymbol that individual subsymbol is modulated as MCCSK.By MCCSK subsymbols with log2MsBit is mapped one by one, and is modulated according to mapping ruler, is sent by emitter;
Preferably,
Step 4, Temporal Basis Function of the receiving terminal generation corresponding to transmitting terminal;
Receiving terminal obtains receiving terminal spectrum amplitude matrix using the method for step 1, and by identical with step 1 transmitting terminal Random phasic serial signal dot product obtain the frequency domain basic function of receiving terminal;
According to the Temporal Basis Function that receiving terminal is obtained with step 2 identical method;
Step 5, the Temporal Basis Function that receiving terminal is obtained according to step 4 carries out MCCSK data demodulation, obtains demodulating data;
MCCSK demodulation mode is that the match peak detection using number of combinations as criterion is carried out on the basis of correlation demodulation. Using peak-peak as primary judgment condition during demodulation, i.e., the corresponding CCSK subsymbols of peak-peak are first detected, then according to step 3 The middle MCCSK subsymbols one by one mapping ruler same with binary number, selection peak-peak is corresponding in corresponding candidate combination CCSK subsymbols, the like carry out nsMinor peaks are detected, obtain the MCCSK subsymbols represented by these CCSK subsymbols.Root According to the mapping ruler determined in step 3, the reception data that these MCCSK subsymbols are represented are obtained.
The derivation for the efficiency of transmission being related in the present invention is as follows:
Assuming that detection bandwidth is B, the sample frequency of base band is fs=B, and the sampling number of each symbol is N, modulation order Number is M.Then the bit rate and spectrum efficiency of traditional Resistant DS Spread Spectrum System are respectively:
The TDCS modulated using CCSK is when spectrum interposition ratio is 0 < β≤1, its bit rate and spectrum efficiency difference For:
Relative to traditional direct spread system, during TDCS actual transmissions, signal energy is only distributed in where spectrum interposition Frequency at, spread equivalent to by original signal in the range of total hole after spectrum aggregating so that its spectrum efficiency is Improve.Especially, when spectrum environment is noiseless, it is all spectrum interposition in frequency band, TDCS can be regarded as a kind of special straight Connect spread spectrum system.But because the number and scope in hole in actual spectrum environment are continually changing, hole is reduced by reducing thresholding The method that ratio improves spectrum efficiency is not easily accomplished, and it is easy and effective to improve spectrum efficiency by increasing order of modulation.
When CCSK superposition subsymbol numbers are nsWhen, from MsContrast system, whereinBit rate now and frequency Spectrum efficiency is:
If thinking farthest to improve transmission rate, MCCSK order of modulation MsIt should be and be no more thanMaximum integer.Root According to stirling formula, obtaining the ratio between MCCSK and tradition CCSK spectrum efficiencies modulated is:
WhereinTo be rounded downwards to x.
Beneficial effect
The present invention devises a kind of MCCSK modulation-demo-demodulation methods based on transform-domain communication, and it is ensureing system rejection to disturbance While ability, the efficiency of transmission of conventional transformation domain communication system is effectively increased.
Brief description of the drawings
Fig. 1 is the TDCS transmitter architectures based on MCCSK;
Fig. 2 is the TDCS receiver structures based on MCCSK;
Fig. 3 is that MCCSK modulates flow;
Fig. 4 is that MCCSK demodulates flow;
Fig. 5 contrasts for MCCSK and CCSK maximum spectral efficiency;
Fig. 6 contrasts for MCCSK and CCSK bit error rate performance;
Fig. 7 contrasts for the bit error rate of MCCSK distinct symbols selection modes;
Embodiment
According to the discussion in above " content of the invention " part, the inventive method is done specifically with reference to accompanying drawing and simulation example It is bright, by constructing the transform domain communication system using MCCSK as modulation and demodulation mode, degree and the bit error rate are improved with spectrum efficiency Lose as standard to weigh the pros and cons of the inventive method.
The present invention relies on transform domain communication system, as depicted in figs. 1 and 2, gives the whole transform domain based on MCCSK The composition and message processing flow of communication system transmitting terminal and receiving terminal:
Step 1, transmitting terminal generation normalization frequency domain basic function;
By energy detection technique, spectrum environment in service bandwidth is sampled and estimated, generation Frequency and Amplitude spectrum.Will Element in Frequency and Amplitude spectrum is compared with interference threshold thresholding one by one, and the corresponding frequency spectrum disposal of element more than thresholding is 0, is represented The frequency spectrum is interfered;The corresponding frequency spectrum disposal of element not less than thresholding is 1, and expression is not interfered or disturbed not tight The frequency spectrum (spectrum interposition) of weight, generation spectrum amplitude matrix A (ω).Pass through linear shift register generation and spectrum amplitude matrix Length identical random phase ejθ(ω)(wherein θ (ω) for pseudo-random function) with frequency dependence, and with spectrum amplitude matrix dot It is multiplied to arrive frequency domain basic functionWhereinFor random phase Vector, C is the cycle that linear shift register generates random phase, mkFor k-th of random real number using C as the cycle.To ensure Transmission signal energy is unified, and energy normalized is carried out according to spectrum interposition number to frequency domain basic functionWherein N and N1Respectively spectrum amplitude matrix points are (with unit symbol sampling number phase 1 number, obtains normalized frequency domain basic function together) and in spectrum amplitude matrix;
Step 2, normalized frequency domain basic function is carried out inverse Fourier transform generation Temporal Basis Function by transmitting terminal;
Normalized frequency domain basic function B (ω) is subjected to inverse Fourier transform, the Temporal Basis Function b of identical points is obtained (t);Temporal Basis Function is stored, for generating MCCSK subsymbol and carrying out MCCSK modulation;
Step 3, transmitting terminal generates MCCSK subsymbols according to Temporal Basis Function, and is carried out using subsymbol after data modulation Transmitting;
As shown in figure 3, carrying out circulative shift operation to Temporal Basis Function, generation M is using T/M as the CCSK of time delay spacing Symbol SymCCSK,0,SymCCSK,1,……,SymCCSK,M-1.If MCCSK subsymbol stacking fold is ns, then can generateIndividual extension subsymbol Wherein x is to extend subsymbol number, x=0,1,2 ... ...,I ≠ j ≠ ... ≠ k ∈ [0, M-1] are different CCSK Symbol, has nsIt is individual to sum up.According to MCCSK modulation orders Ms(And be 2 power), from the extension of generation The larger M of average minimum mark space is chosen in subsymbolsThe subsymbol that individual subsymbol is modulated as MCCSK, is designated as SymMCCSK,0,SymMCCSK,1,……,SymMCCSK,Ms-1, the bit number that each MCCSK subsymbols can carry information is bs= log2Ms.By MCCSK subsymbols and bsBit carries out mapping one by one, and (mapping mode is any, but transmitting terminal and receiving terminal must Must use identical mapping mode, such as MCCSK subsymbols according to superposition CCSK subsymbols sequencing and binary number according to Order from small to large is mapped), and be modulated according to mapping ruler, sent by emitter;
Step 4, Temporal Basis Function of the receiving terminal generation corresponding to transmitting terminal;
Receiving terminal using the method for step 1 obtain receiving terminal spectrum amplitude matrix A ' (ω), and by with step 1 transmitting terminal Middle identical random phasic serial signal ejθ(ω)Dot product obtains the frequency domain basic function B'(ω of receiving terminal).According to step 2 identical side Method obtains the Temporal Basis Function b'(t of receiving terminal).=b (t special) not, when transmitting terminal is identical with the spectrum environment residing for receiving terminal Or when relative to signal being transmitted as slow changing environment, it is believed that B'(ω)=B (ω), b'(t)=b (t);
Step 5, the Temporal Basis Function that receiving terminal is obtained according to step 4 carries out MCCSK data demodulation, obtains demodulating data;
As shown in figure 4, the Temporal Basis Function that the signal received is generated with receiving terminal successively according to symbol lengths is circulated Shift the conjugation of M CCSK subsymbol of generation Dot product, is then integrated, and obtains M correlation function Xcor0,Xcor1,……,XcorM-1, and using peak value judgement to be many according to carrying out Level judgement.The first order:The correlation function where peak-peak, this phase are relatively obtained by the match peak to M correlation function Close function multiplied to this CCSK subsymbol is designated as into n by the conjugate point of reception signal He some CCSK subsymbol1;The second level:Press According to the mapping mode in step 3, all M are searchedsIn individual MCCSK subsymbols and n1Corresponding CCSK subsymbols be overlapped its His CCSK subsymbols, and the correlation function that the conjugation of these CCSK subsymbols and received signal points multiply generation is compared, obtain Correlation function to where maximum match peak point, n is designated as by its corresponding CCSK subsymbol2;It is sequentially completed nsLevel most value search Operation, obtains nsIndividual CCSK subsymbols.The represented MCCSK subsymbols of these CCSK subsymbols combination are the symbol demodulated Number, and according to the mapping relations in step 3, MCCSK subsymbols are mapped as bsThe data of bit obtain demodulating data d'(t).
So far whole communication process is completed.
Performance Evaluation:
The performance of described system and modulation demodulation system, is given below specific simulation example and divides to illustrate the invention Analysis.
Actual transmission bandwidth is set as B=150MBps, the sampling number N=256 of unit symbol waveform can use hole number For n=128, then CCSK order of modulation is up to 256CSK, and the bit number that unit symbol is at most carried is log2N=8.
If based on 8CSK subsymbols (each symbol carries 3 bit informations), using the MCCSK of 2 subsymbol superpositions (being designated as S2-M8-MCSK), its extend subsymbol number beThen MCCSK maximum can use order of modulation Ms=24=16 < 28, each symbol can carry 4 bit informations.For 8CSK, its efficiency of transmission improves 1/3.Table 1 is different CCSK order of modulation and the corresponding MCCSK contrasts of stacking fold, it can be seen that different according to stacking fold, are generated by 8CSK MCCSK spectrum efficiencies can reach 16CSK, 32CSK and 64CSK spectrum efficiency, and stacking fold is more, and improved efficiency is got over Greatly.
The CCSK of table 1 and MCCSK spectrum efficiency contrast
Modulation system Extend subsymbol number Maximum MCCSK subsymbols number Symbol maximum carries bit number Maximum spectral efficiency
8CSK 8 3 0.0234
S2-M8-MCSK 28 16 4 0.0313
S3-M8-MCSK 56 32 5 0.0391
S4-M8-MCSK 70 64 6 0.0469
16CSK 16 4 0.0313
32CSK 32 5 0.0391
64CSK 64 6 0.0469
From the property of number of combinations, when extracting the half that quantity is total amount, number of combinations is most.For MCCSK, whenWhen, extension subsymbol number is most.From Table 2, it can be seen that the increase of the CCSK order of modulation with generation MCCSK, The maximum spectral efficiency that theory can reach is improved, and reaches theoretical maximum spectral efficiency in CCSK maximum modulation exponent numbers.Fig. 5 Contrasted for MCCSK and CCSK maximum spectral efficiency.
The MCCSK theoretical maximum spectral efficiency of table 2
Modulation system Extend subsymbol number Maximum MCCSK subsymbols number Symbol maximum carries bit number Maximum spectral efficiency
S4-M8-MCSK 70 64 6 0.0469
S8-M16-MCSK 12870 8192 13 0.1016
S16-M32-MCSK 601080390 536870912 29 0.2266
S32-M64-MCSK 1.8326E18 1.1529E18 60 0.4688
S64-M128-MCSK 2.3951E37 2.1268E37 124 0.9688
S128-M256-MCSK 5.7687E75 3.6185E75 251 1.9609
MCCSK also increases the bit error rate and system complexity of demodulating end while system spectral efficiency is greatly improved. Fig. 6 compared for CCSK and the MCCSK bit error rate, it can be seen that:The 8CSK and S2-M8- that generation is superimposed based on 8CSK progress 2,3 times 16CSK is compared with S3-M8-32CSK, and its unit symbol carries bit number and adds 1 and 2 bits respectively, and efficiency has obtained difference Degree is heightened, but its bit error rate performance is 10-3The order of magnitude reduces about 2dB and 3dB respectively, and this is due to energy normalizing Change, while symbol is superimposed the match peak of receiving terminal correlation demodulation is reduced;If wanting to reach 32CSK efficiency, S2- M16-32CSK and S3-M8-32CSK can be on low order MCSK by being superimposed realization, but is superimposed the S2- of realization twice The S3-M8-32CSK bit error rates that than three times superpositions of M16-32CSK are realized are low, 10-3The order of magnitude about 2dB poor performance; For with the S2-M16-32CSK and S2-M16-64CSK for being superimposed realization twice by 16CSK, its performance is more or less the same, 10-3The order of magnitude about differs 0.3dB, but can carry 1 bit information more.It is hereby achieved that following rule:
1, MCCSK can be regarded as the CCSK of broad sense, and CCSK is the equal of the MCCSK, i.e. S1-MM- for carrying out 1 superposition MCSK;
2, the MCCSK being overlapped based on identical CCSK subsymbols, unit symbol carry information bit with superposition time Count and increase (preceding M/2), but bit error rate is increased;
3, if wanting, the unit symbol for reaching MCSK carries bit level, and the MCCSK of few superposition is carried out by high-order CCSK Bit error rate performance is better than the MCCSK bit error rate performances that multiple stacking is carried out by low order CCSK;
4, selection is no more than the power of the maximum 2 of MCCSK escape characters as order of modulation, is risen with minimum signal to noise ratio The lifting of maximum spectral efficiency is obtained for cost.
MCCSK bit error rate performance is influenceed by superposition CCSK symbol selection mode, because in demodulation, correlation is solved Adjust the position based on relevant peaks to make decisions, the stacked system of use can increase the correlation between the adjacent subsymbols of MCCSK, lead to Symbol can effectively be reduced by crossing the larger subsymbol combination of the average minimum mark space of selection and being overlapped generation MCCSK subsymbols Sentence the probability of mistake.By taking S2-M8-16CSK as an example, under identical demodulation mode, using two kinds of different symbol selection modes, such as Shown in table 3, it is 1 that average minimum mark space is adjudicated for the first time, but difference occurs in second of judgement average symbol interval, selects The average symbol of mode 1 is selected at intervals of 2, but selection mode 2 only has 1.5.
The average minimum mark space of the MCCSK subsymbols stack combinations of table 3 and for the first time judgement
Data (4 bit) Selection mode 1 Selection mode 2 Data (4 bit) Selection mode 1 Selection mode 2
0000 M1+M3 M1+M5 1000 M1+M2 M5+M8
0001 M2+M4 M2+M6 1001 M2+M3 M6+M1
0010 M3+M5 M3+M7 1010 M3+M4 M7+M2
0011 M4+M6 M4+M8 1011 M4+M5 M8+M3
0100 M5+M7 M1+M4 1100 M5+M6 M5+M3
0101 M6+M8 M2+M5 1101 M6+M7 M6+M4
0110 M7+M1 M3+M6 1110 M7+M8 M7+M1
0111 M8+M2 M4+M7 1111 M8+M1 M8+M2
Average minimum mark space 1 1 1 1
The average minimum mark space of second of judgement of the MCCSK of table 4
Second of judgement The second judgement of selection mode the 1st is combined The second judgement of selection mode the 2nd is combined
M1 M2,M3,M7,M8 M4,M5,M6,M7
M2 M1,M3,M4,M8 M5,M6,M7,M8
M3 M1,M2,M4,M5 M5,M6,M7,M8
M4 M2,M3,M5,M6 M1,M6,M7,M8
M5 M3,M4,M6,M7 M1,M2,M3,M8
M6 M4,M5,M7,M8 M1,M2,M3,M4
M7 M1,M5,M6,M8 M1,M2,M3,M4
M8 M1,M2,M6,M7 M2,M3,M4,M5
Average minimum mark space 2 1.5
It can also be seen that the bigger MCCSK symbol selecting partys of the average minimum mark space of second of judgement from Fig. 7 Formula, bit error rate performance is better in the case of same frequency spectrum.For CCSK, a minor peaks judgement only need to be carried out, between its average minimum Every the interval equal to its order of modulation;For MCCSK, the judgement of first order peak value is identical with CCSK, but grounds of judgment thereafter Different symbol selection modes has different average minimum mark spaces.Average minimum mark space is bigger, demodulating end correlation solution The match peak of tune is less susceptible to sentence mistake from more remote.Especially, when the subsymbol of the increase of superposition number or superposition generation increases Added-time, this phenomenon will be apparent from, because MCCSK demodulating end is selected successively according to the preferential order of peak-peak, because The importance of this average minimum mark space is adjudicated to n-th from the first ordersLevel judgement gradually weakens.It is hereby achieved that following rule Rule:
1, MCCSK distinct symbols selection mode can produce influence to the demodulating end bit error rate, should be according to average minimum intersymbol MCCSK subsymbol is chosen every big coding mapping mode;
2, for multidecision, the importance of the average minimum mark space of judgement is adjudicated to n-th by the first ordersLevel judgement by It is decrescence weak.
Described in detail above is the further description carried out to the purpose of the present invention, technical scheme and beneficial effect. The instantiation that the foregoing is only the present invention is should be understood that, the protection domain being not intended to limit the present invention is all Within the spirit and principles in the present invention, any modification, equivalent substitution and improvements done etc., should be included in the guarantor of the present invention Within the scope of shield.

Claims (7)

1. a kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication, it is characterised in that:Including following step Suddenly:
Step 1, transmitting terminal generation normalization frequency domain basic function;
Step 2, normalized frequency domain basic function is carried out inverse Fourier transform generation Temporal Basis Function by transmitting terminal;
Step 3, transmitting terminal generates MCCSK subsymbols according to Temporal Basis Function, and carries out transmitting after data modulation using subsymbol;
Step 4, Temporal Basis Function of the receiving terminal generation corresponding to transmitting terminal;
Step 5, the Temporal Basis Function that receiving terminal is obtained according to step 4 carries out MCCSK data demodulation, obtains demodulating data;
The normalization frequency domain basic function is generated by following step:
2.1st, by energy detection technique, spectrum environment in service bandwidth is sampled and estimated, generation Frequency and Amplitude spectrum;
2.2nd, by the way that Frequency and Amplitude is composed in element compared with interference threshold thresholding acquisition spectrum amplitude matrix;
2.3rd, by linear shift register generation with the spectrum amplitude matrix length identical random phase, and with frequency spectrum width Spend matrix dot multiplied to frequency domain basic function;
2.4th, normalized frequency domain basic function is obtained by carrying out energy normalized according to spectrum interposition number to frequency domain basic function;
The MCCSK subsymbols are generated by following step:
3.1st, M ranks circulative shift operation is carried out to the Temporal Basis Function and generates M CCSK subsymbol;
3.2nd, n is carried out to the CCSK subsymbolssSuperposition generationIndividual extension subsymbol;
3.3rd, M is chosen from the extension subsymbolsThe subsymbol that individual subsymbol is modulated as MCCSK.
2. a kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication according to claim 1, its It is characterised by:It is describedAnd be 2 power.
3. a kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication according to claim 2, its It is characterised by:The MsSelection is all to meet condition:And for the maximum time-frequency spectrum efficiency in the value of 2 power most It is good.
4. a kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication according to claim 1, its It is characterised by:If reaching same frequency spectrum efficiency, the bigger n of MsSmaller, the bit error rate is lower.
5. according to a kind of any described multiple stage circulation shift keying modulation demodulation sides based on transform-domain communication of claim 1-4 Method, it is characterised in that:The selection MsThe selection principle of individual subsymbol is bigger for average minimum mark space, in same frequency spectrum feelings Bit error rate performance is better under condition.
6. a kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication according to claim 1, its It is characterised by:The MCCSK data demodulation is generated by following step:
8.1st, M CCSK subsymbol is generated to the Temporal Basis Function cyclic shift;
8.2nd, conjugation is taken to the CCSK subsymbols;
8.3rd, to the reception signal and multiplied to M correlation function of conjugate point of CCSK subsymbols;
8.4th, n is carried out to the M correlation functionsLevel judgement obtains nsIndividual CCSK subsymbols;
8.5th, to the nsIndividual CCSK subsymbols are mapped as MCCSK subsymbols and demodulate data.
7. a kind of multiple stage circulation shift keying modulation demodulation method based on transform-domain communication according to claim 6, its It is characterised by:The nsLevel judgement is completed by following step:
9.1st, the correlation function obtained where peak-peak is compared to the match peak of the M correlation function;
9.2nd, corresponding CCSK subsymbols are conjugated to the CCSK subsymbols used in correlation function dot product where the peak-peak to remember For n1
9.3rd, search and the n1Other CCSK subsymbols of corresponding CCSK subsymbols superposition;
9.4th, the conjugation of other described CCSK subsymbols is compared with the correlation function that received signal points multiply generation and obtains maximum Peak value;
9.5th, corresponding CCSK subsymbols are conjugated to the CCSK subsymbols used in correlation function dot product where the peak-peak to remember For n2
9.6th, it is sequentially completed n according to 9.3-9.5 methods describedssLevel most value search operation obtains nsIndividual CCSK subsymbols;
9.7th, by the nsIndividual CCSK subsymbols are mapped as MCCSK subsymbols.
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