CN101267424A - Ultra-broadband wireless communication modulation method based on scanning frequency pulse - Google Patents

Abstract

The invention relates to an ultra-wideband wireless communication modulating method based on sweeping frequency pulse. The united modulation of binary orthogonality keying and phase shift keying of sweeping frequency pulse is used, the orthogonality keying and the direct modulation are integrated, which improves the data transmission rate under a sweeping frequency pulse having the same time width as that of binary orthogonality keying modulation, without introducing overlapping technology, the intersymbol interference brought by pulse overlapping is avoided, and wide space is provided for the appearance of better ultra-wideband modulation and multi-access method based on sweeping frequency pulse.

Description

Ultra-broadband wireless communication modulation method based on scanning frequency pulse

Technical field

Patent of the present invention relates to a kind of ultra-broadband wireless communication modulation method based on scanning frequency pulse, belongs to the communications field.

Background technology

Ultra broadband (UWB) is a rising in recent years and a fast-developing wireless communication technology, is current one of the focus of studying in the world.Relative bandwidth greater than 25% or in 3.1GHz ~ 10.6GH frequency range system bandwidth be called as ultra-wideband communication system greater than the wireless communication system of 500MHz.Being different from the sine wave is the legacy wireless communication system of carrier wave, and owing to modulation bandwidth is expanded to several GHz magnitudes, thereby system can carry out transfer of data with high speed on the basis of occupying utmost point low power spectral density.Simultaneously also to have low cost, low-yield loss, low capture rate, penetration power strong for UWB, advantages such as anti-multipath, therefore the appearance of UWB technology is not taking under the close-packed now frequency spectrum resource situation, and a kind of brand-new voice communications versus data communications mode is provided.The UWB technology is in the short-distance wireless broadband access, and indoor imaging is accurately located and the military communication field has wide application value.

Mainly there are two kinds of physical-layer techniques schemes in UWB at present.A kind of direct sequence spread spectrum (DSS) physical layer technical specification suggestion that is based on wireless pulses (IR); Another kind then is based on the suggestion of multi-carrier OFDM physical layer standard technique specification.UWB system based on the direct sequence spread spectrum (DSS) of wireless pulses (IR) comes transmission information by transmitting and receiving the pulse signal with subnanosecond level.It transmits and receives the narrow pulse signal of pulsewidth less than 1ns with the speed of per second tens of million, and information is modulated in the pulse train of leading accurate timing by pulse position modulation (PPM), pulse amplitude modulation (PAM) or other modulation systems and gone.Another kind is based on the UWB system of multi-carrier OFDM (OFDM), and wherein each subband bandwidth is 528MHz, divides 128 subcarriers, and is mutually orthogonal between each subcarrier, information bit is modulated to respectively on all subcarriers transmits.

Remove this, also have a kind of UWB physical-layer techniques that is in the research starting stage to cause the concern of some tissues and enterprise, promptly based on the ultra-wideband communications of scanning frequency pulse (Chirp).The Chirp signal is a kind of spread-spectrum signal, show chirped characteristic in signal period at a Chirp, the variation that signal frequency is linear along with the variation of time, because the frequency of Chirp signal is the certain bandwidth of meeting " inswept " in a signal period, the Chirp signal is called " swept-frequency signal " again visually.The frequency sweep characteristic of Chirp signal can be applied in the communications field, and the expression data symbol reaches the effect of spread spectrum.This communication mode that carries out spread spectrum with the Chirp signal is called as Chirp spread spectrum (CSS).

Ultra broadband modulation system based on Chirp mainly contains binary orthogonal keying (BOK) and directly modulation (DM) at present.The modulation of binary orthogonal keying is to represent to import data at transmitting terminal generation Up-Chirp and Down-Chirp signal; And directly modulation adopts one road Chirp signal to come the expression data symbol, and data symbol can be a binary character, also can be the multi-system symbol that obtains by various modulation systems.Because Up-Chirp and Down-Chirp signal exist certain correlation to cause indoor intensive many under environment, performance sharply descends.Though and reactance modulation system can utilize the overlapping technology to improve data rate, under synchronous unfavorable situation, also there is big intersymbol interference.

Summary of the invention

The objective of the invention is to defective at the prior art existence, a kind of ultra-broadband wireless communication modulation method based on scanning frequency pulse is provided, be called based on the binary orthogonal keying and the phase-shift keying of scanning frequency pulse and unite modulation, be designated hereinafter simply as the Chirp-BOK-BPSK modulation, when not introducing pulse overlapping technology, improved with BOK modulation and had message transmission rate under the scanning frequency pulse condition of identical time width, avoided the intersymbol interference that brings by the overlapping technology, simultaneously also for to have opened up wide space for the new UWB proposition of modulation system efficiently based on Chirp.

Second purpose of the present invention has been to provide a kind of transmitter of the Chirp-BOK-BPSK of realization modulation.

The 3rd purpose of the present invention has been to provide a kind of receiver of Chirp-BOK-BPSK modulation signal.

For reaching above purpose, the present invention is by the following technical solutions: the present invention adopts to unite with phase-shift keying based on the binary orthogonal keying of scanning frequency pulse and modulates Chirp-BOK-BPSK, binary data information is modulated on the positive antiphase and positive and negative chirp rate of scanning frequency pulse, therefore the amount of information of a scanning frequency pulse is 2 bits, belongs to quaternary modulation.Suppose that the binary data that will send is b _n∈ 1,1} (subscript n is represented n binary data, n ∈ (0 ,+∞)), wherein each data duration is T _s/ 2, if make binary data b _nEven bit data bit b _2n+2Modulation sends the positive and negative frequency sweep slope of pulse, binary data b _nOdd bits bit b _2n+1Modulation sends the positive antiphase of symbol, and then the output signal s of transmitter (t) can be expressed as follows:

$s\left(t\right)=\underset{n=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{b}_{2n+1}a\left(t\right)\cos \left[2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="A20081003386500112.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+b_{2n+2}\frac{\mathrm{\&mu;}}{2}t)t\right]$ $(n-\frac{1}{2})T_s<t<(n+\frac{1}{2})T_s---\left(1\right)$

Wherein a (t) is the envelope of scanning frequency pulse signal, here gets

f ₀Be the centre frequency of scanning frequency pulse, μ is the frequency sweep slope of scanning frequency pulse, and its value equals B/T _s, t is the time.According to binary data to { b _2n+2, b _2n+1Value, the time domain waveform of signal has four kinds of possible states and is expressed as follows respectively:

$\{+1,+1\}{s}_1\left(t\right)=a\left(t\right)\cos \left[2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="A20081003386500112.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\frac{\mathrm{\&mu;}}{2}t)t\right]$

$\{+1,-1\}{s}_2\left(t\right)=a\left(t\right)\cos \left[2\mathrm{\&pi;}(f_0-\frac{\mathrm{\&mu;}}{2}t)t\right]$

$\{-1,+1\}{s}_3\left(t\right)=-a\left(t\right)\cos \left[2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="A20081003386500112.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\frac{\mathrm{\&mu;}}{2}t)t\right]$

$\{-1,-1\}{s}_4\left(t\right)=-a\left(t\right)\cos \left[2\mathrm{\&pi;}(f_0-\frac{\mathrm{\&mu;}}{2}t)t\right]$

So Chirp-BOK-BPSK is modulated to quaternary modulation, whole modulated process comprises serial to parallel conversion, binary phase modulation and three steps of binary orthogonal keying modulation, and knowing clearly, it is as follows to write:

Step 1: transmitter is at first to binary data b _nCarry out serial to parallel conversion, become two paths of signals and be expressed as b respectively _2n+1, b _2n+2And it is T that the time width of every circuit-switched data bit becomes original twice _s

Step 2: after finishing serial to parallel conversion, utilize wherein one road binary data b _2n+1The positive antiphase of modulation scanning frequency pulse realizes the binary phase BPSK modulation in the Chirp-BOK-BPSK modulation.The i.e. b that has underscore on equal sign the right in (1) formula _2n+1, rewrite as follows,

$s\left(t\right)=\underset{n=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}\underset{\&OverBar;}{\underset{\&OverBar;}{b_{2n+1}}}a\left(t\right)\cos \left[2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="A20081003386500112.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+b_{2n+2}\frac{\mathrm{\&mu;}}{2}t)t\right]$ $(n-\frac{1}{2})T_s<t<(n+\frac{1}{2})T_s---\left(3\right)$

B in the formula _2n+1With b _2n+2Represent binary data b respectively _nOdd bits bit and even bit bit, identical in other parameters and the formula (1).

Step 3: utilize other one road binary data b _2n+2The positive and negative frequency sweep slope of modulation scanning frequency pulse is realized the binary orthogonal keying BOK modulation in the Chirp-BOK-BPSK modulation, promptly in (1) formula equal sign the right have underscore b _2n+2, rewrite as follows

$s\left(t\right)=\underset{n=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{b}_{2n+1}a\left(t\right)\cos \left[2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="A20081003386500112.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\underset{\&OverBar;}{\underset{\&OverBar;}{b_{2n+2}}}\frac{\mathrm{\&mu;}}{2}t)t\right]$ $(n-\frac{1}{2})T_s<t<(n+\frac{1}{2})T_s---\left(4\right)$

Through after above three steps, the information of two bits has been modulated onto respectively on the phase place and frequency sweep slope of scanning frequency pulse, has both finished the Chirp-BOK-BPSK modulation.The time width of modulated scanning frequency pulse is T _s, and each scanning frequency pulse through ovennodulation carries two Bit datas, so message transmission rate is 2/T _s

Transmitter of the present invention is a kind of transmitter of realizing the Chirp-BOK-BPSK modulation, as Fig. 3.Its primary structure is to comprise a serial-parallel conversion circuit (31), and data transaction is become two channel parallel datas, realizes the step 1 in this modulator approach; Positive and negative frequency sweep slope is selected circuit (32), according to the binary data b of input _2n+2Select to have scanning frequency pulse (Up-Chirp) cos[2 π (f of positive frequency sweep slope ₀+ μ t/2) t] and negative frequency sweep slope scanning frequency pulse (Down-Chirp) cos[2 π (f ₀-μ t/2) t], realize step 3 in this modulator approach.

Receiver of the present invention is a kind of receiver that receives the Chirp-BOK-BPSK modulation signal, as Fig. 4.Its primary structure comprises two multipliers 4 (1) and 4 (2), two integrators 4 (3) and 4 (4), two each and every one sample circuits 4 (5) and 4 (6) and decision devices 4 (7), as shown in Figure 3.Wherein multiplier and integrator are formed a matched filter, and sample circuit is in order at the scanning frequency pulse complete cycle of (t=nT constantly _s) sample, decision device is adjudicated the data that sample and is demodulated the emission data.Whole receiver structure as shown in Figure 4.

The invention has the beneficial effects as follows: ultra broadband modulator approach provided by the invention has been introduced based on the binary orthogonal keying of scanning frequency pulse and has been modulated the technology that combines with direct chopping phase, having improved the data rate that simple BOK modulation or simple BPSK modulate under the situation of not introducing scanning frequency pulse overlapping technology, also is that the better ultra broadband based on scanning frequency pulse of performance is modulated and wide space has been opened up in the appearance of multi-address method simultaneously.

Description of drawings

Fig. 1 is in the Chirp-BOK-BPSK modulation, the frequency change of scanning frequency pulse and the relation of binary data.Wherein, 1 is the scanning frequency pulse frequency and the time relation curve of binary data+1 o'clock correspondence, and 2 is the scanning frequency pulse frequency sweep rate and the time relation curve of binary data-1 o'clock correspondence.

Fig. 2 is in the Chirp-BOK-BPSK modulation, the phase place of scanning frequency pulse and the relation of binary data.Wherein, 21 is binary data+1 o'clock, and to the phase place and the time relation curve of deserved scanning frequency pulse, 22 is binary data-1 o'clock, to the phase place and the time relation curve of deserved scanning frequency pulse.

Fig. 3 is based on the transmitter principle figure of Chirp-BOK-BPSK modulation.Wherein, 31 is a deserializer, is input as one road serial signal output two-way parallel signal, and 32 is to select circuit fast, according to the binary data b of input _2n+2, select a conduct output among Up-Chirp and the Down-Chirp, 33 is the scanning frequency pulse generating device, in order to produce the Up-Chirp pulse, 34 is the scanning frequency pulse generating device, in order to produce the Down-Chirp pulse, 35 is multiplier, follows the binary data b according to input _2n+1Scanning frequency pulse is carried out phase modulation.

Fig. 4 is based on the receiver principle figure of Chirp-BOK-BPSK modulation.Wherein, 41 is multiplier, and its input is received signal r (t) and local template signal φ ₁(t), 42 is multiplier, and it is input as received signal r (t) and local template signal φ ₂(t), 43 is integrating circuit, to r (t) and φ ₁(t) product carries out integration, and 44 is integrating circuit, to r (t) and φ ₂(t) product carries out integration, and 45 is sample circuit, at t=nT _s(n is an integer) samples to the input of integrating circuit 43 constantly, and 46 is sample circuit, at t=nT _s(n is an integer) samples to the input of integrating circuit 4 constantly, and 47 is a decision device, and it is input as the output of sample circuit 46 and sample circuit 47, in order to recover initial data b _n

Fig. 5 goes up compressed oscillogram with high time-bandwidth product the time.

Fig. 6 goes up the oscillogram that is spread the time.

Fig. 7 is the time domain waveform figure of Chirp-BOK-BPSK modulation signal.Wherein, be the Up-Chirp waveform (a), (b) be-the Up-Chirp waveform, be the Down-Chirp waveform (c), (d) be-the Down-Chirp waveform.

Embodiment

A preferred embodiment of the present invention accompanying drawings is as follows:

Referring to Fig. 1 and Fig. 2, this is based on the ultra-wideband communications modulator approach of scanning frequency pulse, adopt the binary orthogonal keying and the phase-shift keying of scanning frequency pulse to unite modulation Chirp-BOK-BPSK, binary orthogonal keying BOK is combined with direct modulation DM, when not introducing the overlapping technology, improved with BOK modulation and had message transmission rate under the scanning frequency pulse condition of identical time width, avoided the intersymbol interference that brings by the overlapping technology; The concrete operations step is as follows:

The Chirp-BOK-BPSK modulation is a kind of modulation system of leaning on different frequency sweep slope of scanning frequency pulse and phase place thereof to transmit binary data information, is quaternary modulation.If be input to the binary data information of Chirp-BOK-BPSK modulator be: b _n∈ 1,1}, n ∈ [0 ,+∞), the time width of establishing every Bit data is T _s/ 2; A (t) is a rectangular pulse, perhaps can reduce the waveform (as triangular pulse, raised cosine pulse, Gaussian pulse etc.) of intersymbol interference, and simple for expressing, a (t) gets square waveform:

Because of Chirp-BOK-BPSK is modulated to quaternary modulation, therefore before the data input modulator, at first to binary data b _nCarry out serial to parallel conversion, become the odd bits bit and even bit bit two paths of signals is expressed as b respectively _2n+1, b _2n+2And it is T that the time width of every circuit-switched data bit becomes original twice _s, utilize b then _2n+1The positive antiphase of modulation scanning frequency pulse, and b _2n+2The positive and negative frequency sweep slope of modulation scanning frequency pulse, the time width of scanning frequency pulse is T _s, each scanning frequency pulse through ovennodulation will carry two Bit datas like this, so message transmission rate is 2/T _sTherefore modulator has four kinds of different frequency sweep waveforms outputs according to the difference of input bit, represent respectively data message be+1+1 ,+1-1 ,-1+1 and-signal expression during 1-1:

$s_1\left(t\right)=a\left(t\right)\cos \left[2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="A20081003386500112.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\frac{\mathrm{\&mu;}}{2}t)t\right],(n-1/2)T_s<t<(n+1/2)T_s$

$s_2\left(t\right)=a\left(t\right)\cos \left[2\mathrm{\&pi;}(f_0-\frac{\mathrm{\&mu;}}{2}t)t\right],(n-1/2)T_s<t<(n+1/2)T_s$

$s_3\left(t\right)=-a\left(t\right)\cos \left[2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="A20081003386500112.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+\frac{\mathrm{\&mu;}}{2}t)t\right],(n-1/2)T_s<t<(n+1/2)T_s$

$s_4\left(t\right)=-a\left(t\right)\cos \left[2\mathrm{\&pi;}(f_0-\frac{\mathrm{\&mu;}}{2}t)t\right],(n-1/2)T_s<t<(n+1/2)T_s.$

The transmitter of present embodiment is for to unite the transmitter of modulating Chirp-BOK-BPSK based on the binary orthogonal keying and the phase-shift keying of scanning frequency pulse, as shown in Figure 3.The Chirp-BOK-BPSK transmitter mainly contains serial to parallel conversion circuit (31), positive and negative frequency sweep selects circuit (32), scanning frequency pulse generator (33,34) and a multiplier (35) to form.Wherein serial-parallel conversion circuit is with the binary data b of input _nConvert two-way b to _2n+1, b _2n+2And its time width become original twice; Positive and negative frequency sweep selects circuit according to data b _2n+2Select pulse of positive frequency sweep slope or the pulse of negative frequency sweep slope; The scanning frequency pulse generator is used for producing the pulse of positive frequency sweep slope, negative frequency sweep slope pulse respectively; The main effect of multiplier is the phase modulated that realizes scanning frequency pulse, and two input is respectively data b _2n+1(33) or (34) scanning frequency pulse waveform producing, its output is modulated Chirp-BOK-BPSK signal.

The receiver of present embodiment is for to unite the receiver of modulating Chirp-BOK-BPSK based on the binary orthogonal keying and the phase-shift keying of scanning frequency pulse, as shown in Figure 4.Mainly the achieve a butt joint compression of the modulated scanning frequency pulse received of coherent demodulation module, when the pulse that receives produces scanning frequency pulse with high time-bandwidth product as figure (5) when local template signal is complementary, otherwise the pulse that receives will be spread in time, shown in figure (6).Sample circuit is at t=nT _sThe place samples to the pulse of having compressed.Initial data b is adjudicated and then recovered to decision device according to the two-way output of sample circuit _n

Claims (3)

1. ultra-broadband wireless communication modulation method based on scanning frequency pulse, it is characterized in that adopting binary orthogonal keying and phase-shift keying to unite modulation Chirp-BOK-BPSK based on scanning frequency pulse, binary orthogonal keying BOK is combined with direct modulation DM, when not introducing the overlapping technology, improved with BOK modulation and had message transmission rate under the scanning frequency pulse condition of identical time width, avoided the intersymbol interference that brings by the overlapping technology;

The concrete operations step is as follows:

Step 1: transmitter is at first to binary data b _nCarry out serial to parallel conversion, become two paths of signals and be expressed as b respectively _2n+1, b _2n+2And it is T that the time width of every circuit-switched data bit becomes original twice _s

Step 2: after finishing serial to parallel conversion, utilize wherein one road binary data b _2n+1The positive antiphase of modulation scanning frequency pulse realizes uniting the binary phase BPSK modulation of modulating Chirp-BOK-BPSK based on the binary orthogonal keying and the phase-shift keying of scanning frequency pulse.The output signal s of transmitter (t) as shown in the formula:

$s\left(t\right)=\underset{n=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{b}_{2n+1}a\left(t\right)\cos \left[2\mathrm{\&pi;}(f_0+b_{2n+2}\frac{\mathrm{\&mu;}}{2}t)t\right]$ $(n-\frac{1}{2})T_s<t<(n+\frac{1}{2})T_s$

A in the formula (t) is the envelope of scanning frequency pulse signal, here gets

f ₀Be the centre frequency of scanning frequency pulse, μ is the frequency sweep slope of scanning frequency pulse, and its value equals B/T _s, t is the time, b _2n+1With b _2n+2Represent binary data b respectively _nOdd bits bit and even bit bit;

Step 3: utilize other one road binary data b _2n+2The positive and negative frequency sweep slope of modulation scanning frequency pulse realizes that uniting the binary orthogonal keying BOK that modulates Chirp-BOK-BPSK based on the binary orthogonal keying of scanning frequency pulse with phase-shift keying modulates, the output signal of transmitter as shown in the formula:

$s\left(t\right)=\underset{n=0}{\overset{\&infin;}{\mathrm{\&Sigma;}}}{b}_{2n+1}a\left(t\right)\cos \left[2\mathrm{\&pi;}(f_0+b_{2n+2}\frac{\mathrm{\&mu;}}{2}t)t\right]$ $(n-\frac{1}{2})T_s<t<(n+\frac{1}{2})T_s$

Through after above three steps, the information of two bits has been modulated onto respectively on the phase place and frequency sweep slope of scanning frequency pulse, has both finished the Chirp-BOK-BPSK modulation, and the time width of modulated scanning frequency pulse is T _s, and each scanning frequency pulse through ovennodulation carries two Bit datas, so message transmission rate is 2/T _s

2. the ultra-broadband wireless communication modulation method based on scanning frequency pulse according to claim 1, it is characterized in that described transmitter is for to unite the transmitter of modulating Chirp-BOK-BPSK based on the binary orthogonal keying and the phase-shift keying of scanning frequency pulse, its structure is: an output of a serial-parallel converter (31) is directly inputted to a multiplier (35), and another output is through a scanning frequency pulse generator (33 of selecting circuit (32) and two parallel connections fast, 34) produce Up-Chirp and Down-Chirp respectively, import described multiplier (35) afterwards.

3. the ultra-broadband wireless communication modulation method based on scanning frequency pulse according to claim 2, it is characterized in that with the matching used receiver of described transmitter for to unite the receiver of modulating Chirp-BOK-BPSK based on the binary orthogonal keying and the phase-shift keying of scanning frequency pulse, its structure is: two multipliers (41,42) respectively through two integrators (43,44) and two samplers (45,46) backs connect a decision device (47).

Images