CN102546501B - Multivariate position random polar MCP-EBPSK (Multivariate Continuous Phase-Extended Binary Phase Shift Keying) modulation and demodulation method - Google Patents

Abstract

The invention discloses a multivariate position random polar MCP-EBPSK (Multivariate Continuous Phase-Extended Binary Phase Shift Keying) modulation and demodulation method, which is based on a corrected random polar continuous phase-extended binary phase shift keying modulation mode. The method involves a multivariate position random polar MCP-EBPSK modulator and a multivariate position random polar MCP-EBPSK signal demodulator. The multivariate position random polar MCP-EBPSK modulator is used for carrying out corrected random polar continuous phase keying to different phase modulation periods of sine wave carriers according to multivariate information symbols; and the multivariate position random polar MCP-EBPSK signal demodulator comprises an impulse filter used for highlighting the phase modulation information of received signals and eliminating the polar change of the received signals so that the demodulation performance is not influenced by the modulation of the multivariate position random polar. In the invention, the transmission rate and the spectrum utilization rate of a random polar CP-EBPSK communication system are multiplied by modulation signals, and the system has narrow occupied bandwidth, wide code rate application range, good demodulation performance and good flexibility for use.

Description

The random polarity MCP-EBPSK modulation and demodulation of multielement positional method

Technical field

The present invention relates to the information modulation and demodulation in digital communication, the particularly MCP-EBPSK modulation and demodulation method of the random polarity of a kind of multielement positional, belongs to the technical field of high spectrum utilization digital information transmission.

Background technology

The broadband wireless business demand of rapid growth has proposed more and more higher requirement to radio communication, directly cause aerial radio frequency more and more crowded, particularly along with the third generation (3G) and the 4th generation (4G) wide-band mobile communication network development, almost depleted compared with the continuous frequency spectrum of low-frequency range.Europe 10MHz frequency spectrum 20 years usufructuary auction prices are up to 4,000,000,000 Euros, and in China, spend to be also hard to buy best frequency and bandwidth.Therefore, the same with the energy and water resources, frequency spectrum is also national grand strategy resource, compresses to greatest extent wireless transmission frequency spectrum and has important practical significance and direct economic benefit.And for high-speed transfer information in unit frequency band, will improve as far as possible the availability of frequency spectrum (examining with bps/Hz), this has become core competitiveness indicator and the key common technology of generation information transmission system.

1, CP-EBPSK modulation

In order to tighten frequency spectrum, we once invented one " binary phase shift keying of continuous phase expansion " (CP-EBPSK:Continue Phase-Extended Binary Phase Shift Keying) modulation and (saw " the extended binary phase shift keying modulation and demodulation method of frequency spectrum compression ", invention patent mandate notification number: CN101582868B), its uniform expression is:

s ₀(t)＝sinω _ct， 0≤t<T

$S_1\left(t\right)=\left\{\begin{array}{cc}\sin ({\mathrm{\&omega;}}_{c}t\&PlusMinus;\mathrm{\&Delta;}\sin {\mathrm{\&omega;}}_{c}t),& 0\&le;t<\mathrm{\&tau;},0<\mathrm{\&Delta;}<1\\ \sin {\mathrm{\&omega;}}_{c}t,& 0<\mathrm{\&tau;}\&le;t<T\end{array}\right.---\left(1\right)$

Wherein, s ₀and s (t) ₁(t) represent respectively the modulation waveform of code element " 0 " and " 1 ", ω _cfor the angular frequency of modulated carrier, 0< Δ <1 is phase-modulation index.Visible code-element period T=2 π N/ ω _ccontinued N>=1 carrier cycle, the modulation period of " 1 " code element has continued K<N carrier cycle, and K and N are integer to ensure modulation complete cycle.

From (1) formula, CP-EBPSK modulation waveform has following features:

1) phase place is continuous, and time waveform is also continuous;

2) angular frequency of data " 0 " is ω _c, the angular frequency of data " 1 " is ω _c± Δ ω _ccos ω _ct (signal phase ω _ct ± Δ ω _csin ω _ct is for the derivative of time t), be changed to ± Δ of instantaneous frequency ω _c, be a finite value, in the time of Δ <<1, the frequency spectrum of CP-EBPSK modulated wave is expected to be tightened;

3) if getting τ=T can realize the modulation in single carrier cycle, thereby the highest code check numerically just equals carrier frequency, and it is the widest that bandwidth reaches.Along with the reducing of modulation duty cycle τ/T=K/N (or modulation index Δ reduce),, on certain power spectral density (PSD:Power Spectrum Density) level, the bandwidth of the modulated waveform of CP-EBPSK can be tending towards so-called super arrowband (UNB:Ultra Narrow Band) always.

For example, in (1) formula, get Δ=0.01, N=16, K=2, f _c=ω _c/ 2 π=40kHz, obtain the time waveform of CP-EBPSK modulation signal as shown in Fig. 1 (a) solid line, it is compared with the time waveform of the sinusoidal signal (line of dots in Fig. 1 (a)) of standard, and the signal waveform of visible CP-EBPSK modulation approaches sine wave very much.Fig. 1 (b) is the power spectrum of CP-EBPSK modulation signal, and wherein ordinate is that power spectrum amplitude using carrier frequency place is as 0dB.From Fig. 1 (b), in the time of Δ <<1, the energy height of CP-EBPSK modulation signal is concentrated, and carrier frequency (being positioned at 40kHz place) amplitude is higher than the about 70dB of other sideband (1 thousands of times).

Specific implementation is: when modulator input symbols " 0 ", modulator is just selected s ₀(t) the waveform sample output shown in, on the contrary in the time being input as code element " 1 ", modulator is selected s ₁(t) the waveform sample output shown in, the phase-modulation index Δ of all code elements " 1 " institute corresponding modulating waveform all equates, and remains unchanged.

2, the CP-EBPSK of random polarity modulation

Because phase-modulation index Δ is larger, better for the demodulation performance of CP-EBPSK modulation signal, therefore the selection of Δ is often because the compromise availability of frequency spectrum and capacity usage ratio of needs is can not value too little simultaneously.For example, in order to obtain high code check, we get f _c(now code check is f for=30MHz, N=4 _c/ N=30/N=7.5Mbps), K=2 and Δ=0.1 carried out emulation, now the power spectrum of CP-EBPSK modulation signal is as shown in Fig. 2 (a), in figure, abscissa is frequency, the MHz of unit, ordinate is relative amplitude, and the dB of unit has got 10,000 code elements when rated output spectrum.The power spectrum sideband of visible now CP-EBPSK modulation signal just fails to reach the stricter requirement lower than-60dB, is mainly because contain higher discrete spectrum (being line spectrum) component in sideband.Therefore,, if can remove or reduce the line spectrum in CP-EBPSK modulation signal power spectrum sideband, be expected further to reduce the sidebands levels of CP-EBPSK modulation signal power spectrum.

Notice the keying modulation period of CP-EBPSK in each code element " 1 ", (1) the phase-modulation index Δ in formula or remain unchanged, staggered reindexing (+Δ or-Δ), this regularity is the basic reason that produces line spectrum component (corresponding the cycle sinusoidal component of time domain) in PSD sideband.And if sending code element when " 1 ", allow symbol (the being polarity of modulation) change at random (get at random+Δ or-Δ) of phase-modulation index Δ, just be expected to reduce or eliminate sideband line spectrum, thereby further tighten the power spectrum of CP-EBPSK modulation signal, reduce the interference to adjacent channel, improve the availability of frequency spectrum.So, we have proposed again a kind of " communication system and the communication means thereof of the CP-EBPSK of pseudo random sequence modulation " (application for a patent for invention number: 201110092668.X), by increase a pseudo-random sequence generator in original CP-EBPSK modulator, utilize the pseudo random number of its generation to choose at random the polarity (being the positive and negative of symbol) of Δ, in (1) formula, modulation for data " 0 " is constant, and for data " 1 ", investigate the value of the current random number of this pseudo random sequence, if this value is 0, get+Δ in (1) formula, if this value is 1, get-Δ in (1) formula, thereby the randomness of utilizing code element " 1 " keying modulation period phase place to change has been removed the most of line spectrum on CP-EBPSK modulation signal PSD main lobe and secondary lobe, the frequency spectrum of modulated signal is tightened more (shown in Fig. 2 (b), exceeding 20dB), to its can be like a cork with harsher-60dB power bandwidth is examined, and demodulation performance is substantially unaffected.

3, MPPSK modulation

Classical pulse modulation application as radar system and pulse ultra-broad band (IR-UWB) communication system in, conventionally adopt pulsion phase to transmit different symbolic information for the difference of carrier position, as pulse position modulation (PPM:Pulse Position Modulation).We once utilized this point, invent " multielement positional phase shift keying (MPPSK:M-ary Position Phase Shift Keying) modulation and demodulation method " (patent of invention number: ZL200710025202.1), utilize the out of phase saltus step position of multiple information symbol offset of sinusoidal carrier wave to carry out phase shift keying, thereby binary phase shift keying (the EBPSK:Extended Binary Phase Shift Keying) modulator approach of expansion (for the i.e. special case of " unified binary quadrature modulation demodulation method " of ZL200710025203.6 patent that we invent before this) is extended to multi-system modulation and demodulation, in spectrum structure and transmitting power almost under constant condition, transmission code rate and the availability of frequency spectrum have doubled.

4, the demodulation of EBPSK modulation signal

About the demodulation of EBPSK modulation signal, we are at application for a patent for invention " a kind of demodulation method for unifying binary modulation signal " (application number: 200810124475.6, publication number: CN101316252) in, once disclose a kind of infinite impulse response (IIR) filter of digital zero group delay, be used for giving prominence to the phase hit of EBPSK modulation signal.This digital zero group delay filter is made up of a pair of conjugation zero point and a pair of conjugate pole, zero frequency is lower than pole frequency, signal carrier frequency is located between zero frequency and pole frequency, be positioned near the intersection point of filter amplitude frequency curve and phase frequency curve, to utilize its transient response to make described modulation signal produce overshoot phenomenon at phase-modulation place by the output of filter, and the close degree of zero frequency and pole frequency is not inferior to 10 of carrier frequency ^-2the order of magnitude.

" for strengthening the impact filtering method of asymmetric binary modulating signal " (application number: 200910029875.3, publication number: CN101599754) by increasing at least more one or more pairs of conjugate poles near the original limit at digital zero group delay filter, higher overshoot amplitude and better demodulation performance are obtained, therefore be referred to as digital shock filter.

Summary of the invention

For continuing to improve the spectrum structure of random polarity CP-EBPSK modulation signal, the object of the present invention is to provide a kind of CP-EBPSK of correction (to be denoted as MCP-EBPSK, be Modified CP-EBPSK) modulator approach, and be extended to the random polarity MCP-EBPSK modulation and demodulation method of multi-system, to improve exponentially transmission code rate and the availability of frequency spectrum of random polarity CP-EBPSK communication system.

For solving the problems of the technologies described above, realize above-mentioned technique effect, the present invention is achieved through the following technical solutions:

The random polarity MCP-EBPSK modulation and demodulation of a kind of multielement positional method, step comprises:

1, optimize the power spectrum shape of random polarity CP-EBPSK modulation signal and promote demodulation performance.

From Fig. 1 (b) and Fig. 2, CP-EBPSK modulation and random polarity CP-EBPSK modulation signal have produced the 2nd higher secondary lobe of specific power spectrum main lobe at 2 frequency multiplication places of carrier frequency, affected the further deflation of signal bandwidth, have also disperseed the energy of signal.Its reason is mainly the modulation rate of signal phase too fast.For this reason, first the present invention introduces one and is less than 1 power spectrum shape adjustment coefficient η (when η=1 time be the random polarity CP-EBPSK modulation signal that does not add correction) in the expression formula of random polarity CP-EBPSK modulation signal, thereby obtains the expression formula of the random polarity MCP-EBPSK modulation system as shown in (2) formula:

s ₀(t)＝sinω _ct， 0≤t<NT _c

$s_1\left(t\right)=\left\{\begin{array}{cc}\sin ({\mathrm{\&omega;}}_{c}t+\mathrm{\&xi;}\&CenterDot;\mathrm{\&Delta;}\sin \left(\mathrm{\&eta;}{\mathrm{\&omega;}}_{c}t\right)),& 0\&le;t<{\mathrm{KT}}_c\\ \sin {\mathrm{\&omega;}}_{c}t,& 0<{\mathrm{KT}}_c\&le;t<{\mathrm{NT}}_c\end{array}\right.---\left(2\right)$

Wherein, T _c=2 π/ω _cfor carrier cycle, { 1,1} has determined the polarity of phase place Stochastic Modulation to ξ ∈, and η ∈ (0,1) is MCP-EBPSK and modulates the power spectrum shape adjustment coefficient of introducing.The implication of other variable is identical with (1) formula.

The power spectrum of η=1,1/2,1/3 equal conditions contrasting from Fig. 3 (a)～Fig. 3 (e), 1/4 and 1/5 random polarity MCP-EBPSK modulation signal, we can see that PSD energy is to carrier frequency and the concentrated trend of main lobe really.This is very natural, because in the time of η=0, (2) formula just deteriorates to the sine wave of standard.100,000 code elements and 2 when the power spectrum of calculating chart 3, are chosen ²⁶the fast Fourier transform (FFT) of point is to ensure high as far as possible precision and resolution.

And from the demodulation performance of these the 5 kinds of random polarity MCP-EBPSK modulation signals shown in Fig. 4 to recently, in the time of η <1, because the energy of random polarity MCP-EBPSK modulation signal is concentrated towards its carrier frequency and PSD main lobe more, result has obtained better bit error rate performance.Especially improve amplitude maximum with the demodulation performance of η=1/2 o'clock, for example in Fig. 4 when signal to noise ratio snr=32dB, the demodulation bit error rate of the random polarity MCP-EBPSK modulation of η=1/2 is modulated and has been reduced nearly 2 orders of magnitude than the random polarity CP-EBPSK of η=1.

2, random polarity MCP-EBPSK modulator approach is extended to multi-system by binary system.

With reference to the thinking of aforementioned MPPSK, the random polarity MCP-EBPSK modulation expression formula by the definition of (2) formula, be expanded into the MCP-EBPSK modulation system of the random polarity of multielement positional as shown in (3) formula:

$s_k\left(t\right)=\left\{\begin{array}{ccc}\sin {\mathrm{\&omega;}}_{c}t,& 0\&le;t<{\mathrm{NT}}_c,& k=0\\ \left\{\begin{array}{c}\sin {\mathrm{\&omega;}}_{c}t,\\ \sin ({\mathrm{\&omega;}}_{c}t+\mathrm{\&xi;}\&CenterDot;\mathrm{\&Delta;}\sin \left({\mathrm{\&eta;\&omega;}}_{c}t\right)),\\ \sin {\mathrm{\&omega;}}_{c}t,\end{array}\right.& \begin{array}{c}0\&le;t\&le;(k-1){\mathrm{KT}}_c,\\ (k-1){\mathrm{KT}}_c<t<(k-r_g){\mathrm{KT}}_c,\\ (k-r_g){\mathrm{KT}}_c\&le;t<{\mathrm{NT}}_c,\end{array}& 1\&le;k\&le;M-1\end{array}\right.---\left(3\right)$

Wherein, k=0,1 ..., M-1 is M binary information symbol, has the value that M>2 kind is different; 0≤r _g<1 is the symbol protection Separation control factor.By M, K, N, η, Δ and r _gform one group " modulation parameter " changing signal bandwidth, efficiency of transmission and demodulation performance.

As M=2 and r _g=0 o'clock, (3) formula just deteriorated to (2) formula.

From the power spectrum contrast of the quaternary CP-EBPSK modulation signal of random polarity shown in random polarity CP-EBPSK modulation signal and Fig. 5 (b) shown in Fig. 5 (a), compare from the power spectrum of the quaternary MCP-EBPSK modulation signal of the random polarity of η=1/2 shown in the random polarity MCP-EBPSK modulation signal of η=1/2 shown in Fig. 5 (c) and Fig. 5 (d), after we can see that introducing multi-system modulates, the power spectrum shape of random polarity CP-EBPSK modulation signal and random polarity MCP-EBPSK modulation signal is substantially constant, but line spectrum component has obviously reduced.

3, the impact filtering response of the random polarity MCP-EBPSK modulation signal of multielement positional is carried out to multichannel judgement and realize demodulation.

First the receiver of the random polarity MCP-EBPSK modulation signal of multielement positional still adopts digital shock filter the phase-modulation of input signal to be converted into the parasitic amplitude modulation of output signal, then is aided with multichannel adaptive threshold judgement and detects the demodulation that realizes the random polarity MCP-EBPSK modulation signal of described multielement positional.And described digital shock filter is a kind of special iir filter, in extremely narrow pass band width, present trap-selecting frequency characteristic, phase hit small in modulation signal is converted into the impact in amplitude, thereby give prominence to the different wave shape on amplitude output signal, be conducive to realize by threshold judgement the demodulation of phase-modulated signal.

From the demodulation bit error rate contrast of the quaternary MCP-EBPSK modulation signal of the random polarity of the random polarity CP-EBPSK modulation shown in Fig. 6, quaternary CP-EBPSK modulation and η=1/2, under the same error rate, the required signal to noise ratio (SNR) of the random polarity quaternary MCP-EBPSK modulation signal of demodulation η=1/2 is minimum on the contrary.This is to waste the line spectrum component of transmitting power and the result that power spectrum energy is concentrated more owing to having removed major part.The more important thing is, compare with the CP-EBPSK modulation of random polarity, because the random polarity quaternary MCP-EBPSK modulation of η=1/2 makes transmission bit rate multiplication, reduced half therefore transmit the required signal to noise ratio of each data (being EbN0).

We's ratio juris is described as follows:

Taking the MCP-EBPSK modulation system of random polarity as basis, the MCP-EBPSK modulation system of described random polarity is expressed as (2) formula, and (2) formula is expanded to multi-system from binary system, and its expression formula is as shown in (3) formula.By M, K, N, η, Δ and r _gform one group " modulation parameter " changing signal bandwidth, efficiency of transmission and demodulation performance.

The MCP-EBPSK modulator of the random polarity of multielement positional comprises a pseudo-random sequence generator, utilize that it produces only have-1 and+1 two kind may value pseudo random number ξ control the symbol of Δ, i.e. the phase-modulation polarity of non-" 0 " data in (2) formula or (3) formula.The MCP-EBPSK modulator of the random polarity of multielement positional is engraved in the position occurring in each non-" 0 " code-element period while adopting M binary information symbol directly to control the phase hit of sinusoidal carrier by (3) formula.The MCP-EBPSK modulator of the random polarity of multielement positional is introduced power spectrum shape adjustment coefficient η and is regulated the shape of modulated signal power spectrum and promote demodulation performance.

The MCP-EBPSK demodulator of the random polarity of multielement positional comprises a digital shock filter, is used for giving prominence to receiving the phase modulation information of signal and eliminating its change in polarity, makes demodulation performance not be subject to the impact of phase-modulation polarity change at random.Described digital shock filter is a kind of infinite impulse response band pass filter, by forming at a pair of conjugation zero point and at least one pair of conjugate pole, zero frequency is lower than pole frequency, signal carrier frequency is higher than the zero frequency of shock filter but lower than all pole frequencies, and the close degree of zero frequency and pole frequency should not be inferior to 10 of signal carrier frequency ^-2～10 ^-3magnitude, to utilize its transient response to make described modulation signal produce overshoot phenomenon at phase-modulation place by the output of filter.The MCP-EBPSK demodulator of the random polarity of multielement positional utilizes digital shock filter to export envelope in amplitude and locational difference to described multi-system signal code, adopts multichannel decision method to realize the demodulation of M system symbol.

The present invention has following beneficial effect:

1) availability of frequency spectrum significantly promotes.Continuous because CP-EBPSK modulation system changes in keying period phase place, adopt random polar keying modulation significantly to reduce the height of line spectrum in power spectrum signal, so the very bandwidth that modulation signal takies is narrow, there is the very high availability of frequency spectrum, more approach traditional " super arrowband ".Introduce the shape that power spectrum shape adjustment coefficient η has optimized again power spectrum, not only make can transmit more information symbol and introduce multi-system modulation in a code-element period, the rate of information throughput significantly improves but also has reduced the quantity of line spectrum, thereby the very bandwidth of modulation signal is narrow, the availability of frequency spectrum is greatly improved.

2) capacity usage ratio significantly promotes.Because can making demodulator, shock filter is not subject to the impact of the random reversion of signal phase modulation polarity, also because power spectrum shape adjustment coefficient η can force down the secondary lobe height (for example, as η <1/2) at carrier wave 2 frequency multiplication places or make it to carrier frequency close (for example, when η=1/2), make the energy of modulation signal more concentrated, thereby the demodulation performance of system is also promoted.Again due to the sinusoidal carrier to same, adopt random polarity multi-system MCP-EBPSK modulation of the present invention and employing existing random polarity binary system CP-EBPSK as a comparison to modulate the modulation signal power obtaining identical, but the information bit rate of transmitting significantly improves, thereby without intersymbol interference in the situation that, transmitting the required signal to noise ratio of each data is E _b/ N ₀also reduce at double, capacity usage ratio significantly promotes.

3) application is wide.Aerial frequency spectrum is rare natural resources, and efficient modulation-demo-demodulation method of the present invention has reduced taking of frequency spectrum resource from bottom, be more suitable for adopting cognitive radio (Cognitive Radio, CR) thought further realizes dynamic spectrum access and static arrowband and occupies and combine, make good use of public resource from top layer, be particluarly suitable for various Bandwidth-Constrained channels and bring into play its advantage as applications such as digital Audio Broadcasting, digital handset, power line carrier, plastic fibers.

Above-mentioned explanation is only the general introduction of technical solution of the present invention, in order to better understand technological means of the present invention, and can be implemented according to the content of specification, below with preferred embodiment of the present invention and coordinate accompanying drawing to be described in detail as follows.The specific embodiment of the present invention is provided in detail by following examples and accompanying drawing thereof.

Brief description of the drawings

Fig. 1 (a) is the sinusoidal signal of standard and the contrast of the time waveform of CP-EBPSK modulation signal, and Fig. 1 (b) is the power spectrum of CP-EBPSK modulation signal.

Fig. 2 is that CP-EBPSK modulation contrasts with the power spectrum signal of random polarity CP-EBPSK modulation in the time of Δ=0.1, wherein Fig. 2 (a) is the power spectrum of CP-EBPSK modulation signal, and Fig. 2 (b) is the power spectrum of random polarity CP-EBPSK modulation signal.In figure, abscissa is frequency, and unit is MHz, and ordinate is relative amplitude, and unit is dB, has chosen 10,000 code elements when rated output spectrum.

Fig. 3 be when carrier frequency be that 21.4MHz, sample frequency are 214MHz, Δ=0.1, K:N=2:10, the power spectrum of the MCP-EBPSK modulation signal of random polarity, in figure, abscissa is frequency, unit is MHz, ordinate is relative amplitude, unit is dB.Wherein, Fig. 3 (a) is that η=1 is the power spectrum of uncorrected random polarity CP-EBPSK modulation signal; Fig. 3 (b) is the power spectrum of the random polarity MCP-EBPSK modulation signal of η=1/2; Fig. 3 (c) is the power spectrum of the random polarity MCP-EBPSK modulation signal of η=1/3; Fig. 3 (d) is the power spectrum of the random polarity MCP-EBPSK modulation signal of η=1/4; Fig. 3 (e) is the power spectrum of the random polarity MCP-EBPSK modulation signal of η=1/5.

Fig. 4 is the demodulation performance contrast to 5 kinds of random polarity MCP-EBPSK modulation signals shown in Fig. 3.

Fig. 5 is to be the power spectrum contrast of 21.4MHz, sample frequency 3 kinds of random polarity CP-EBPSK modulation signals while being 214MHz, Δ=0.1, K:N=2:10, M=4 when carrier frequency, has chosen 100,000 code elements and 2 when rated output spectrum ²⁶point FFT, in figure, abscissa is frequency, and unit is MHz, and ordinate is relative amplitude, and unit is dB.Wherein, Fig. 5 (a) is the Fig. 2 (a) redrawing for convenient contrast, i.e. the power spectrum of CP-EBPSK modulation signal; Fig. 5 (b) is the power spectrum of quaternary CP-EBPSK modulation signal; Fig. 5 (c) is the Fig. 3 (a) redrawing for convenient contrast, i.e. the power spectrum of the uncorrected random polarity CP-EBPSK modulation signal of η=1; Fig. 5 (d) is the power spectrum of the quaternary CP-EBPSK modulation signal of random polarity; Fig. 5 (e) is the Fig. 3 (b) redrawing for convenient contrast, i.e. the power spectrum of the random polarity MCP-EBPSK modulation signal of η=1/2; Fig. 5 (f) is the power spectrum of the quaternary MCP-EBPSK modulation signal of the random polarity of η=1/2.

Fig. 6 is the error rate contrast of the quaternary MCP-EBPSK modulation signal of the random polarity of random polarity CP-EBPSK modulation, quaternary CP-EBPSK modulation and η=1/2, and modulation parameter is Δ=0.1, K:N=2:10, M=4.

Fig. 7 is that the circuit of the MCP-EBPSK modulator of the random polarity of multielement positional is realized block diagram.

Fig. 8 is the random polarity quaternary MCP-EBPSK modulation signal time domain waveform example of η=1/2, and modulation parameter is Δ=0.1, K:N=2:10, M=4.Abscissa represents sampling number, and ordinate represents signal amplitude.

Fig. 9 is the power spectrum of the random polarity quaternary MCP-EBPSK modulation signal of η=1/2, and when bit rate is about 4.28Mbps, at the only 31.694kHz of bandwidth at-70.88dB place, the availability of frequency spectrum is up to 135bps/Hz.

Figure 10 is that the circuit of the random polarity MCP-EBPSK demodulator of multielement positional based on digital shock filter multichannel judgement is realized block diagram.

Figure 11 impacts filter coefficient based on the given numeral of the present invention, and the ber curve of the random polarity quaternary MCP-EBPSK modulation signal of demodulation η=1/2 that emulation obtains, does not all adopt chnnel coding.

Embodiment

Below with reference to the accompanying drawings and in conjunction with the embodiments, describe the present invention in detail.

1, the MCP-EBPSK modulator of the random polarity of multielement positional

Fig. 7 be described random polarity multi-system MCP-EBPSK signal modulator realize block diagram, described modulator comprises a pseudo-random sequence generator, a waveform sample memory module, a clock generator, a digital to analog converter (DAC), also has an alternative digital filter.Its course of work is as follows:

1) what described pseudo-random sequence generator utilized that it produces only have-1 and+1 two kind may value pseudo random number ξ ∈ { 1,1} controls the symbol of phase-modulation index Δ, i.e. the phase-modulation polarity of non-" 0 " data in (2) formula or (3) formula.

2) described waveform sample memory module possesses the function of read-only memory (ROM) and MUX (MUX) simultaneously, has stored the modulation signal S shown in (3) formula _k(t) waveform sample, (please notes that different wave shape is very little) as shown in Figure 8.Under the rhythm control of the clock pulse producing at described clock generator, go out corresponding modulation waveform sample by the output common choice of the multi-system information symbol sequence of inputting and described pseudo-random sequence generator.

3) when send in multi-system information sequence " 0 " code element time, directly select modulation waveform sample S ₀(t) export, needn't consider the output valve of described pseudo-random sequence generator; And when sending when non-" 0 " code element, the pseudo random number ξ ∈ that must produce according to pseudo-random sequence generator the value of 1,1}, select phase-modulation index+Δ and-the corresponding modulation waveform of Δ, directly completed computing " ξ Δ ".

4) selected go out corresponding modulation waveform sample after described digital filter filtering, send into again described DAC, converted the random polarity multi-system MCP-EBPSK modulation signal output of simulation to.

5) for example, because the power spectrum secondary lobe of the random polarity MCP-EBPSK modulation signal of multielement positional of the present invention significantly forces down (in Fig. 9 lower than-70dB), so conventionally no longer need the digital filtering link in Fig. 7.

In order to provide availability of frequency spectrum index intuitively, according to FCC (FCC) harsh-60dB bandwidth criteria, CP-EBPSK modulation to random polarity CP-EBPSK modulation, multi-system and the random polarity CP-EBPSK modulation carried out-60dB bandwidth of the multielement positional of η=1/2 and availability of frequency spectrum statistics, result as shown in Table 1 and Table 2.Signal carrier frequency in table is 21.4MHz, and in the time of N=30, the bit rate of CP-EBPSK modulation is about 713.3kbps, and the bit rate of quaternary CP-EBPSK modulation is about 1.426Mbps.Under visible all situations, the availability of frequency spectrum has all exceeded 230bps/Hz, far above used modulation system

When table 1 K=2 3 kinds of modulation systems-contrast of 60dB bandwidth and the availability of frequency spectrum

When table 2 N=30 3 kinds of modulation systems-contrast of 60dB bandwidth and the availability of frequency spectrum

2, the MCP-EBPSK demodulator of the random polarity of multielement positional

Figure 10 be the random polarity of described multielement positional MCP-EBPSK demodulator realize block diagram, described demodulator comprises an analog to digital converter (ADC), a digital shock filter, an envelope detector, M-1 integration decision device, and a multiplexer.Its course of work is as follows:

1) described ADC gives digital shock filter after the MCP-EBPSK modulation signal of the random polarity of multielement positional of the simulation receiving (generally having down-converted to intermediate-freuqncy signal) is converted to digital signal.

2) described digital shock filter is a kind of special IIR type digital band-pass filter, by forming at a pair of conjugation zero point and at least one pair of conjugate pole, the carrier frequency of the MCP-EBPSK modulation signal of the random polarity of multielement positional is higher than the zero frequency of shock filter but lower than all pole frequencies, and the close degree of zero frequency and pole frequency at least will reach 10 of signal carrier frequency ^-2～10 ^-3magnitude.Conventionally the transfer function of IIR digital filter based can be write as following form:

$H\left(z\right)=\frac{\underset{j=0}{\overset{J}{\mathrm{\&Sigma;}}}{b}_j\&CenterDot;z^{-j}}{1-\underset{i=1}{\overset{I}{\mathrm{\&Sigma;}}}{a}_i\&CenterDot;z^{-i}}=\frac{1+\underset{j=1}{\overset{J}{\mathrm{\&Sigma;}}}{b}_j\&CenterDot;z^{-j}}{1-\underset{i=1}{\overset{I}{\mathrm{\&Sigma;}}}{a}_i\&CenterDot;z^{-i}}---\left(4\right)$

Wherein a ₀=b ₀=1, z is Z-transformation domain variable, b _jfor conjugation zero point, a _ifor conjugate pole.Again because digital shock filter is by forming at a pair of conjugation zero point and at least one pair of conjugate pole, therefore 2=J≤I in (4) formula.

For the random polarity MCP-EBPSK modulation signal of multielement positional of η=1/2, the present embodiment utilizes automatic search to obtain following shock filter design result:

The 1 pair of conjugation 0. 1 is to conjugate pole:

b ₁＝-1.618640351773825，b ₂＝1；

a ₁＝-1.449036912558672，a ₂＝0.802018791906955。

The 1 pair of conjugation 0. 2 is to conjugate pole:

b ₁＝-1.618995687176257，b ₂＝1；

a ₁＝-1.817361012430280，a ₂＝1.436763412570941，a ₃＝-0.513559435879943，

a ₄＝0.079854429688135。

The 1 pair of conjugation 0. 3 is to conjugate pole:

b ₁＝-1.618495523346314，b ₂＝1；

a ₁＝-1.973401307621458，a ₂＝1.707892238042286，a ₃＝-0.700903759306155，

a ₄＝0.130496898023677，a ₅＝-0.002568125322230，a ₆＝0.000019814679492。

The 1 pair of conjugation 0. 4 is to conjugate pole:

b ₁＝-1.618291601965442，b ₂＝1；

a ₁＝-2.168053222193768，a ₂＝2.187962929169438，a ₃＝-1.299383678361045，

a ₄＝0.492378155435954，a ₅＝-0.120711291984894，a ₆＝0.018620887125597。

a ₇＝-0.001643075331654，a ₈＝0.000066921767388。

The 1 pair of conjugation 0. 5 is to conjugate pole:

b ₁＝-1.618170608461342，b ₂＝1；

a ₁＝-1.939474919995603，a ₂＝1.681237455829215，a ₃＝-0.732433281562777，

a ₄＝0.188918888567184，a ₅＝-0.030731478479574，a ₆＝0.003265945453330，

a ₇＝-0.000226833477136，a ₈＝0.000010064787649，a ₉＝-0.000000262232114，

a ₁₀＝0.000000003180191。

3) output signal of described envelope detector impact filter is carried out low-pass filtering again after taking absolute value, receive the phase modulation information of signal and eliminate its change in polarity thereby coordinate with shock filter for outstanding, making demodulation performance not be subject to the impact of pseudo random sequence phase-modulation.

4) utilize digital shock filter to export envelope in amplitude and locational difference to described signal, adopt multichannel decision method to realize the demodulation of M binary information symbol.As shown in figure 10, the impact filtering signal envelope of described envelope detector output is divided into M-1 road and carries out respectively integration judgement, m (1≤m≤M-1) road decision device is only responsible for distinguishing symbol " m ", near the position that only may occur at code-element period internal symbol " m " to sample of signal integration after foundation " thresholding m " adjudicate, to distinguish symbol " m " and symbol " 0 " (certainly want under the control of lock-out pulse in place, and omitted the common practise of this this area of bit synchronization DISCHARGE PULSES EXTRACTION in Figure 10).In other words, the MCP-EBPSK demodulator of the random polarity of multielement positional of the present invention utilizes the amplitude of impact filtering output signal envelope to distinguish symbol " m " and symbol " 0 "; Utilize the position (with respect to the time delay of symbol " 1 ") that symbol " m " occurs in code-element period to distinguish each non-" 0 " information symbol.And for sprocket bit " 1 ", we can make the corresponding duration processed of symbol " 1 " is simply K ₁be slightly larger than other M-2 the corresponding duration K processed of non-" 0 " information symbol.For example in the time of K=2, getting K1 is 3 or 4, and after impact filtering and envelope detection, the corresponding impact amplitude of symbol " 1 " can obviously exceed other M-1 symbol amplitude of (comprising symbol " 0 ") like this.

5) utilize described multiplexer JiangM-1 road court verdict to merge output, obtain the demodulation result (if the input signal of M-1 road decision device does not all exceed the threshold value of response, last demodulation result is just adjudicated as symbol " 0 ") of final M binary information sequence.Due in the time there is no intersymbol interference, the judgement Output rusults non-overlapping copies in time on each road, thereby the output of described multiplexer is exactly the stack of M-1 road decision device Output rusults.

Impact filter coefficient based on above designed numeral the MCP-EBPSK modulator-demodulator of the random polarity of the quaternary has been carried out to emulation, obtain ber curve as shown in figure 11, show to adopt 1 pair of conjugation 0. 3 to the digital filter demodulation performance of conjugate pole best (situation that exceedes 3 pairs of conjugate poles is not drawn), and operand is moderate.

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations.Within the spirit and principles in the present invention all, any amendment of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (3)

1. the random polarity MCP-EBPSK modulation and demodulation of a multielement positional method, is characterized in that step comprises:

1) optimize the expansion of random polarity continuous phase binary phase shift keying (CP-EBPSK:Continue Phase-Extended Binary Phase Shift Keying) modulation signal power spectrum shape and promote demodulation performance;

The uniform expression of CP-EBPSK modulation is:

S ₀(t)＝sinω _ct， 0≤t<T

$S_1\left(t\right)=\left\{\begin{array}{c}\sin ({\mathrm{\&omega;}}_{c}t\&PlusMinus;\mathrm{\&Delta;}\sin {\mathrm{\&omega;}}_{c}t),0\&le;t<\mathrm{\&tau;},0<\mathrm{\&Delta;}<1\\ \sin {\mathrm{\&omega;}}_{c}t,0<\mathrm{\&tau;}\&le;t<T\end{array}\right.---\left(1\right)$

Wherein, S ₀and S (t) ₁(t) represent respectively the modulation waveform of code element " 0 " and " 1 ", ω _cfor the angular frequency of modulated carrier, 0< Δ <1 is phase-modulation index; Visible code-element period T=2 π N/ ω _ccontinued N>=1 carrier cycle, the modulation period of " 1 " code element has continued K<N carrier cycle, and K and N are integer to ensure modulation complete cycle;

In expression formula (1), introduce one and be less than 1 power spectrum shape adjustment coefficient η, in the time of η=1, do not add the random polarity CP-EBPSK modulation signal of correction, thereby obtain the expression formula of the random polarity MCP-EBPSK modulation system as shown in (2) formula:

S ₀(t)＝sinω _ct， 0≤t<NT _c

$S_1\left(t\right)=\left\{\begin{array}{c}\sin ({\mathrm{\&omega;}}_{c}t+\mathrm{\&xi;}\&CenterDot;\mathrm{\&Delta;}\sin \left(\mathrm{\&eta;}{\mathrm{\&omega;}}_{c}t\right)),0\&le;t<{\mathrm{KT}}_c\\ \sin {\mathrm{\&omega;}}_{c}t,0<{\mathrm{KT}}_c\&le;t<{\mathrm{NT}}_c\end{array}\right.---\left(2\right)$

Wherein, T _c=2 π/ω _cfor carrier cycle, { 1,1} has determined the polarity of phase place Stochastic Modulation to ξ ∈, and η ∈ (0,1) is MCP-EBPSK and modulates the power spectrum shape adjustment coefficient of introducing, and the implication of other variable is identical with (1) formula;

2) random polarity multielement positional phase shift keying (MPPSK:M-ary Position Phase Shift Keying) modulation system is extended to multi-system by binary system:

The random polarity MCP-EBPSK modulation expression formula by the definition of (2) formula, be expanded into the MCP-EBPSK modulation system of the random polarity of multielement positional as shown in (3) formula:

$S_k\left(t\right)=\left\{\begin{array}{c}\sin {\mathrm{\&omega;}}_{c}t,0\&le;t<{\mathrm{NT}}_c,k=0\\ \left\{\begin{array}{c}\sin {\mathrm{\&omega;}}_{c}t,0\&le;t\&le;(k-1){\mathrm{KT}}_c,\\ \sin ({\mathrm{\&omega;}}_{c}t+\mathrm{\&xi;}\&CenterDot;\mathrm{\&Delta;}\sin \left(\mathrm{\&eta;}{\mathrm{\&omega;}}_{c}t\right)),(k-1){\mathrm{KT}}_c<t<(k-r_g){\mathrm{KT}}_c,1\&le;k\&le;M-1\\ \sin {\mathrm{\&omega;}}_{c}t,(k-r_g){\mathrm{KT}}_c\&le;t<{\mathrm{NT}}_c,\end{array}\right.\end{array}\right.---\left(3\right)$

Wherein, k=0,1 ..., M-1 is M binary information symbol, has the value that M>2 kind is different; 0≤r _g<1 is the symbol protection Separation control factor; By M, K, N, η, Δ and r _gform one group " modulation parameter " changing signal bandwidth, efficiency of transmission and demodulation performance; As M=2 and r _g=0 o'clock, (3) formula just deteriorated to (2) formula;

3) the impact filtering response of the random polarity MCP-EBPSK modulation signal of multielement positional is carried out to multichannel judgement and realizes demodulation:

To the MCP-EBPSK modulation signal of the random polarity of multielement positional receiving, first adopt digital shock filter the phase-modulation that receives signal to be converted into the parasitic amplitude modulation of output signal; Be aided with again the judgement of multichannel adaptive threshold and detect the demodulation that realizes the random polarity MCP-EBPSK modulation signal of described multielement positional;

Realize the multi-system MCP-EBPSK signal modulator of the random polarity of this modulator approach, comprise a pseudo-random sequence generator, a waveform sample memory module, a clock generator and a digital to analog converter DAC, the course of work of this modulator is as follows:

What a1) pseudo-random sequence generator utilized that it produces only have-1 and+1 two kind may value pseudo random number ξ ∈ { 1,1} controls the symbol of phase-modulation index Δ, i.e. the phase-modulation polarity of non-" 0 " data in (2) formula or (3) formula;

A2) waveform sample memory module possesses the function of read-only memory and MUX simultaneously, has stored the modulation signal S shown in (3) formula _k(t) waveform sample; Under the rhythm control of the clock pulse producing at clock generator, go out corresponding modulation waveform sample by the output common choice of the multi-system information symbol sequence of inputting and described pseudo-random sequence generator;

A3) when send in multi-system information sequence " 0 " code element time, directly select modulation waveform sample S ₀(t) output; And when sending when non-" 0 " code element, the pseudo random number ξ ∈ that must produce according to pseudo-random sequence generator the value of 1,1}, select phase-modulation index+Δ and-the corresponding modulation waveform of Δ, directly completed computing " ξ Δ ";

A4) selected go out corresponding modulation waveform sample send into described DAC, converted the random polarity multi-system MCP-EBPSK modulation signal output of simulation to;

Described digital shock filter is a kind of IIR type digital band-pass filter, by forming at a pair of conjugation zero point and at least one pair of conjugate pole, the carrier frequency of the modulation signal receiving is higher than the zero frequency of shock filter but lower than all pole frequencies, and the close degree of zero frequency and pole frequency at least will reach 10 of signal carrier frequency ^-2～10 ^-3magnitude; The transfer function of described IIR digital filter based is as follows:

$H\left(z\right)=\frac{\underset{j=0}{\overset{J}{\mathrm{\&Sigma;}}}{b}_j\&CenterDot;z^{-j}}{1-\underset{i=1}{\overset{I}{\mathrm{\&Sigma;}}}{a}_i\&CenterDot;z^{-i}}=\frac{1+\underset{j=1}{\overset{J}{\mathrm{\&Sigma;}}}{b}_j\&CenterDot;z^{-j}}{1-\underset{i=1}{\overset{I}{\mathrm{\&Sigma;}}}{a}_i\&CenterDot;z^{-i}}---\left(4\right)$

Wherein a ₀=b ₀=1, z is Z-transformation domain variable, b _jfor conjugation zero point, a _ifor conjugate pole; Again because digital shock filter is by forming at a pair of conjugation zero point and at least one pair of conjugate pole, therefore 2=J≤I in (4) formula.

2. the random polarity MCP-EBPSK modulation and demodulation of multielement positional according to claim 1 method, is characterized in that also comprising digital filter, described step a4) in, modulation waveform sample is sent into described DAC after digital filter filtering again.

3. the random polarity MCP-EBPSK modulation and demodulation of a multielement positional method, is characterized in that step comprises:

1) optimize the expansion of random polarity continuous phase binary phase shift keying (CP-EBPSK:Continue Phase-Extended Binary Phase Shift Keying) modulation signal power spectrum shape and promote demodulation performance;

The uniform expression of CP-EBPSK modulation is:

S ₀(t)＝sinω _ct， 0≤t<T

$S_1\left(t\right)=\left\{\begin{array}{c}\sin ({\mathrm{\&omega;}}_{c}t\&PlusMinus;\mathrm{\&Delta;}\sin {\mathrm{\&omega;}}_{c}t),0\&le;t<\mathrm{\&tau;},0<\mathrm{\&Delta;}<1\\ \sin {\mathrm{\&omega;}}_{c}t,0<\mathrm{\&tau;}\&le;t<T\end{array}\right.---\left(1\right)$

Wherein, S ₀and S (t) ₁(t) represent respectively the modulation waveform of code element " 0 " and " 1 ", ω _cfor the angular frequency of modulated carrier, 0< Δ <1 is phase-modulation index; Visible code-element period T=2 π N/ ω _ccontinued N>=1 carrier cycle, the modulation period of " 1 " code element has continued K<N carrier cycle, and K and N are integer to ensure modulation complete cycle;

In expression formula (1), introduce one and be less than 1 power spectrum shape adjustment coefficient η, in the time of η=1, do not add the random polarity CP-EBPSK modulation signal of correction, thereby obtain the expression formula of the random polarity MCP-EBPSK modulation system as shown in (2) formula:

S ₀(t)＝sinω _ct， 0≤t<NT _c

$S_1\left(t\right)=\left\{\begin{array}{c}\sin ({\mathrm{\&omega;}}_{c}t+\mathrm{\&xi;}\&CenterDot;\mathrm{\&Delta;}\sin \left(\mathrm{\&eta;}{\mathrm{\&omega;}}_{c}t\right)),0\&le;t<{\mathrm{KT}}_c\\ \sin {\mathrm{\&omega;}}_{c}t,0<{\mathrm{KT}}_c\&le;t<{\mathrm{NT}}_c\end{array}\right.---\left(2\right)$

Wherein, T _c=2 π/ω _cfor carrier cycle, { 1,1} has determined the polarity of phase place Stochastic Modulation to ξ ∈, and η ∈ (0,1) is MCP-EBPSK and modulates the power spectrum shape adjustment coefficient of introducing, and the implication of other variable is identical with (1) formula;

2) random polarity multielement positional phase shift keying (MPPSK:M-ary Position Phase Shift Keying) modulation system is extended to multi-system by binary system:

The random polarity MCP-EBPSK modulation expression formula by the definition of (2) formula, be expanded into the MCP-EBPSK modulation system of the random polarity of multielement positional as shown in (3) formula:

$S_k\left(t\right)=\left\{\begin{array}{c}\sin {\mathrm{\&omega;}}_{c}t,0\&le;t<{\mathrm{NT}}_c,k=0\\ \left\{\begin{array}{c}\sin {\mathrm{\&omega;}}_{c}t,0\&le;t\&le;(k-1){\mathrm{KT}}_c,\\ \sin ({\mathrm{\&omega;}}_{c}t+\mathrm{\&xi;}\&CenterDot;\mathrm{\&Delta;}\sin \left(\mathrm{\&eta;}{\mathrm{\&omega;}}_{c}t\right)),(k-1){\mathrm{KT}}_c<t<(k-r_g){\mathrm{KT}}_c,1\&le;k\&le;M-1\\ \sin {\mathrm{\&omega;}}_{c}t,(k-r_g){\mathrm{KT}}_c\&le;t<{\mathrm{NT}}_c,\end{array}\right.\end{array}\right.---\left(3\right)$

Wherein, k=0,1 ..., M-1 is M binary information symbol, has the value that M>2 kind is different; 0≤r _g<1 is the symbol protection Separation control factor; By M, K, N, η, Δ and r _gform one group " modulation parameter " changing signal bandwidth, efficiency of transmission and demodulation performance; As M=2 and r _g=0 o'clock, (3) formula just deteriorated to (2) formula;

3) the impact filtering response of the random polarity MCP-EBPSK modulation signal of multielement positional is carried out to multichannel judgement and realizes demodulation:

To the MCP-EBPSK modulation signal of the random polarity of multielement positional receiving, first adopt digital shock filter the phase-modulation that receives signal to be converted into the parasitic amplitude modulation of output signal; Be aided with again the judgement of multichannel adaptive threshold and detect the demodulation that realizes the random polarity MCP-EBPSK modulation signal of described multielement positional;

4) realize the MCP-EBPSK demodulator of the random polarity of multielement positional of this demodulation method, comprise an analog to digital converter ADC, a digital shock filter, envelope detector, a M-1 integration decision device and a multiplexer, the course of work of this demodulator is as follows:

B1) ADC gives digital shock filter after the MCP-EBPSK modulation signal of the random polarity of multielement positional of the simulation receiving is converted to digital signal;

B2) output signal of described envelope detector impact filter is carried out low-pass filtering again after taking absolute value;

B3) utilize digital shock filter to export envelope in amplitude and locational difference to described signal, adopt multichannel decision method to realize the demodulation of M binary information symbol;

The impact filtering signal envelope of envelope detector output is divided into M-1 integration decision device of M-1 route and carries out respectively integration judgement, m (1≤m≤M-1) road decision device is only responsible for distinguishing symbol " m ", near the position that only may occur at code-element period internal symbol " m ", adjudicate according to " thresholding m " after to sample of signal integration, to distinguish symbol " m " and symbol " 0 ";

B4) utilize multiplexer JiangM-1 road court verdict to merge output, obtain the demodulation result of final M binary information sequence;

Described digital shock filter is a kind of IIR type digital band-pass filter, by forming at a pair of conjugation zero point and at least one pair of conjugate pole, the carrier frequency of the modulation signal receiving is higher than the zero frequency of shock filter but lower than all pole frequencies, and the close degree of zero frequency and pole frequency at least will reach 10 of signal carrier frequency ^-2～10 ^-3magnitude; The transfer function of described IIR digital filter based is as follows:

$H\left(z\right)=\frac{\underset{j=0}{\overset{J}{\mathrm{\&Sigma;}}}{b}_j\&CenterDot;z^{-j}}{1-\underset{i=1}{\overset{I}{\mathrm{\&Sigma;}}}{a}_i\&CenterDot;z^{-i}}=\frac{1+\underset{j=1}{\overset{J}{\mathrm{\&Sigma;}}}{b}_j\&CenterDot;z^{-j}}{1-\underset{i=1}{\overset{I}{\mathrm{\&Sigma;}}}{a}_i\&CenterDot;z^{-i}}---\left(4\right)$

Wherein a ₀=b ₀=1, z is Z-transformation domain variable, b _jfor conjugation zero point, a _ifor conjugate pole; Again because digital shock filter is by forming at a pair of conjugation zero point and at least one pair of conjugate pole, therefore 2=J≤I in (4) formula.