JP2894381B2 - Spread spectrum communication equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum communication apparatus in which an error rate characteristic caused by an interference wave is less deteriorated.

[0002]

2. Description of the Related Art Conventionally, as a spread spectrum communication apparatus in which the deterioration of the error rate characteristic caused by this kind of interference wave is small, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. 58-200649. FIG. 30 is a block diagram of the demodulation unit of the spread spectrum communication apparatus disclosed in the above document. In the figure,
1A and 1B are correlators, 3 is an AGC amplifier, 4A and 4B are bandpass filters, 5 is a detector, 18 is a local reference code generator, 19 is a delay line, 20 is a demodulator 21 is a switch,
22 is a subtractor.

Next, the operation will be described. Received signal Vi
Are the same local reference code sequences V _C1 and V _C2 (for example, a sequence length of 10) as the transmission code sequences in the two correlators 1A and 1B.
23 PN code). Where V
_C2 is have configured delay line 19 to delay by a time corresponding to a sequence length of about 510 bits for example V _C1. Reference numerals 4A and 4B denote bandpass filters having a pass band substantially equal to the band of the information signal, 22 denotes a subtractor, 3 denotes an AGC amplifier, and 5 denotes a detector which detects one of the correlator output signals V _d1 and V _d2. The output is fed back to the AGC amplifier 3. 20 is a typical demodulator, for example synchronous detection and synchronization determiner, a carrier regenerator, a synchronous detector, identification, have a regenerator, the information data signal V _I transmitted from the transmitting side
Is demodulated.

Next, an outline of interference wave suppression of the spread spectrum communication apparatus of FIG. 30 will be described with reference to FIG. FIG.
1 (a) is a spectrum of transmission data transmitted from the transmission side. FIG. 31B shows the spectrum of the received signal Vi, and shows a case where a narrow band interfering wave is mixed in the received signal as an interference wave. When there is a timing of the spread code sequence on the transmission side and the local reference code sequence V _C1 , the output V _d1 of the correlator 1A is compressed as shown in FIG. Is spread in reverse. At this time, since the output V _d2 of the correlator 1B cannot be correlated, the spectrum of the signal and the interference wave is expanded regardless of whether the input signal is a desired wave or an interference wave as shown in FIG. Conversely, if the timing of the spreading code sequence on the transmitting side matches the local reference code sequence V _C2 , the spectrum distribution of the signals V _d1 and V _d2 is in the opposite state. The above correlator output V
The spectra after _d1 and _Vd2 have passed through the narrow band pass filters 4A and 4B are shown in FIGS. 31 (e) and (f), respectively.
Shown in Then, the difference output V
yields a. As shown in FIG. 31 (g), most of the signal Va is a signal component, and slightly contains pseudo noise having a very low power density (a desired signal component despread by the correlator 1B). Va in which the interference wave is suppressed can be obtained. Similarly, when a spread spectrum signal from another station is mixed in the received signal Vi instead of a narrow band desired wave, the despreading is performed by the correlators 1A and 1B, and then the subtractor 2
It is deducted and suppressed by 2.

However, there is a problem that an interference wave component remains as it is without being suppressed for an interference wave as shown in the following example. FIG. 32 is a diagram for explaining the operation of suppressing interference waves by the demodulation unit of the spread spectrum communication apparatus of FIG. FIG. 32 (a) shows the vector locus of the narrow band interference wave mixed into the received signal Vi of FIG. 30 together with the transition of time. In the figure, I and Q indicate an in-phase axis and an orthogonal axis, respectively. Also, in the same figure, the vector of the interference wave at each time point is represented by an orthogonal component. Here, the signal component exists on the in-phase axis, the interference wave is sinusoidal, and the interference wave power is 100 times the carrier power of the signal component (10 times in voltage ratio).
And the center frequency difference between the interference wave and the signal wave is T
An example of {(π / 4) / 7} · Ts where s is the transmission data interval will be described.

If there is a difference between the center frequencies of the interference wave and the signal wave, the vector trajectory of the interference wave rotates with time as shown in FIG. In FIG. 32 (b),
The figure shows the in-phase axis component of the interference wave obtained by projecting the interference wave on the in-phase axis, and this is one factor that degrades the error rate characteristics.
FIGS. 32C and 32D show local reference code sequences V _C1 and V _C2 generated by local reference code generators 18 and 19, respectively. Here, the code sequence shows an example of a PN code having a sequence length of 7. In the correlators 1A and 1B and the bandpass filters 4A and 4B in FIG. 30, the in-phase component of the interference wave and the local reference codes V _C1 and V _C2 are multiplied and averaged, respectively. The vectors of the interference waves shown in FIGS. 32C and 32D indicate the in-phase axis components of the interference wave obtained by multiplying the interference wave mixed into the received signal Vi with the local reference code sequence. And
The band-pass filter cancels out the upward and downward ones by averaging, and acts to suppress the in-phase component of the interference wave during data demodulation. The remaining vector components are residual interference wave components. FIG. 32 (c)
In the case of, the residual interference wave component on the in-phase axis is 10, but FIG.
In the case of 2 (d), the following values are obtained. 10−10 × 2 ^{1/2, that} is, when there is a difference between the center frequencies of the interference wave and the signal wave, different interference wave components are detected by the local reference codes V _C1 and V _C2, and Va , The interference wave component of the next value remains without being suppressed. 10− (10−10 × 2 ^1/2 ) = 10 × 2 ^1/2 This is obtained by delaying the correlation characteristics between the interference wave component mixed into the received signal and the local reference code V _C1 and the above-mentioned interference wave component. This is a phenomenon that occurs because the correlation characteristics with the local reference code V _C2 do not always match.

[0007]

Since the conventional spread spectrum communication apparatus is configured as described above, the spread spectrum communication apparatus includes a case where there is a difference between the center frequency of the interference wave and the center frequency of the signal wave mixed in the received signal. When the correlation characteristic between the spread code sequence and the interference wave does not match the correlation characteristic between the time-delayed spread spectrum code and the interference wave, there remains a problem that the interference wave is not effectively suppressed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and includes a case where there is a difference between the center frequencies of an interference wave and a signal wave. It is an object of the present invention to obtain a spread spectrum communication apparatus capable of effectively suppressing an interference wave even when the correlation characteristics of the spread spectrum code and the interference wave do not match.

[0009]

According to a first aspect of the present invention, there is provided a spread spectrum communication apparatus.
In a spread spectrum communication apparatus that performs spread spectrum transmission of transmission data from the transmission side and transmits the data, and performs correlation detection on the detection signal using the same spread spectrum code sequence as the transmission side and demodulates the transmission data, the following elements are used. M1 and D1 assuming that the modulating unit has
And D2. (A) Modulation section M1 having the following elements: (a1) Spread spectrum code generator for generating a spread spectrum code sequence; (a2) Multiplying transmission data with the above spread spectrum code sequence to obtain a spread spectrum signal Multiplier, (a
3) observation channel insertion means for inserting an observation channel into the above spread spectrum code sequence or the above spread spectrum signal, (a4) a waveform shaping filter for shaping the spread spectrum signal into which the observation channel is inserted, (a5)
A modulator for obtaining a modulated wave by multiplying the output of the above-mentioned waveform shaping filter and a carrier wave; (b) a demodulation unit D1 having the following elements;
(B1) a waveform shaping filter for shaping the waveform of the detection signal;
(B2) a sampler that samples the output of the waveform shaping filter, (b3) a serial-parallel converter that classifies the output of the sampler into observation channel sample values and signal channel sample values, and (b4) from the above observation channel sample values. ,
Estimating means for estimating an interference wave component mixed in a signal channel; (b5) a canceller for subtracting the estimated value of the interference wave component from the signal channel sample value; (b6)
A matched filter for detecting the correlation of the canceller output using the same spread spectrum code sequence as that of the transmitting side, (b
8) a data determiner for determining transmission data with respect to the output of the matched filter, (c) a demodulation unit D2 having the following elements, (c1) a waveform shaping filter for shaping a waveform of a detection signal, and (c2) a waveform shaping filter described above. (C3) a sampler that samples the output, (c3) a channel matched filter that performs correlation detection on the sampler output using the same code sequence as the spread spectrum code sequence on the transmission side, (c4)
(C5) a correlation canceler for subtracting an interference wave component remaining after signal channel correlation detection using a correlation detection value output from each stage of the delay device, (c5) c6) A data determiner that determines transmission data for the correlation canceler output. A spread spectrum communication apparatus according to claim 2, wherein transmission data is transmitted from the transmission side, and the reception side demodulates the transmission data by performing correlation detection on the detection signal using the same spread spectrum code sequence as the transmission side. In the device, the modulator having the following elements is M2, and the demodulator is D
3, D4 includes M2 and at least one of D3 and D4. (A) Modulating section M2 having the following elements: (a1) Spread spectrum code generator for generating a spread spectrum code sequence; (a2) Multiplying transmission data with the above spread spectrum code sequence to obtain a spread spectrum signal (A3) observation channel insertion means for inserting an observation channel into the above-mentioned spread spectrum code sequence or the above-mentioned two spread spectrum signals, and (a4) a spectrum into which the above-mentioned two observation channels are inserted. A timing offsetter for controlling one of the timings so that the signal channels of the spread signals do not overlap with each other in time; (a5) a waveform shaping filter for shaping the waveforms of the two systems of spread spectrum signals; and (a6) a waveform shaping filter of the two systems A quadrature modulator that modulates mutually orthogonal carriers using the output of the waveform shaping filter as a modulation signal, (b) (B1) a waveform shaping filter that shapes the in-phase and quadrature-axis components of the detected signal, (b2) a sampler that samples the output of each of the above-described waveform shaping filters, (b3) A timing offsetter for controlling the time relationship between the sampler output values, (b4) a serial-to-parallel converter for classifying the respective sampler outputs into observation channel sample values and signal channel sample values, and (b5) each of the above. (B6) estimating means for estimating the interference wave component of the signal channel from the observed channel sample value of (b6), a canceller for subtracting the estimated value from the respective signal channel sample values, (b6)
7) a matched filter that performs correlation detection on the respective canceler outputs using the same spread spectrum code sequence as that on the transmitting side; (b8) a data determiner that determines transmission data for the respective matched filter outputs;
(C) a demodulation unit D4 having the following elements; (c1) a waveform shaping filter that shapes the in-phase axis component and the quadrature-axis component of the detected signal; and (c2) a sampler that samples the output of each of the above-described waveform shaping filters. , (C3)
A timing offsetter for controlling the mutual timing relationship between the sample values of the in-phase axis component and the quadrature axis component of the waveform-shaped detection signal; (c4) the in-phase axis component and the quadrature axis component whose mutual timing relationship is controlled (C5) a delay unit that holds the output of each of the above-mentioned channel matched filters, and (c6) a delay unit that holds the output of each of the above-mentioned channel matched filters. A correlation canceller for subtracting interference wave components remaining after signal channel correlation detection using the output correlation detection value; and (c7) a data determiner for determining transmission data with respect to the correlation canceler output. In the spread spectrum communication apparatus according to claim 3,
This is provided with at least one of the modulation units M1 and M2 defined above. In the spread spectrum communication apparatus according to claim 4, the demodulation units D1, D2, D
3, D4.

[0010]

In the spread spectrum communication apparatus according to the first aspect of the present invention, the transmission side modulating section has a spread spectrum code sequence or a spread spectrum code obtained by multiplying transmission data and a spread spectrum code sequence. In the signal, an observation channel is inserted, a spread spectrum signal in which the signal channel and the observation channel exist alternately is generated and transmitted, and a demodulation unit on the receiving side that receives the signal generates a signal component in a signal channel of the detection signal. And the interference wave component mixed in, and only the interference wave component exists in the observation channel. Therefore, the sampler output of the detected signal is divided into a signal channel and an observation channel, and the estimated value of the interference wave component existing in the signal channel obtained by the estimating means from the sample value of the observation channel is subtracted from the sample value of the signal channel. The correlation detection is performed by using the same spread spectrum code sequence as that of the transmission side by the matched filter, or the correlation detection is performed by using the same spread spectrum code sequence as that of the transmission side by the channel matched filter for the sampler output of the detection signal. Then, by the delay unit and the correlation canceller, from the correlation detection value of the signal channel,
By subtracting the interference wave component remaining after the signal channel correlation estimated from the correlation detection value of the observation channel at the timing adjacent to the correlation timing, there is a case where there is a difference between the center frequencies of the interference wave and the signal wave, and thus the spread spectrum. Even when the correlation characteristic between the code and the interference wave and the correlation characteristic between the delayed spread spectrum code and the interference wave do not match, the interference wave component mixed in the detection signal can be suppressed.

According to a second aspect of the present invention, in the spread spectrum communication apparatus, the transmitting side modulating section inserts an observation channel into a spread spectrum code sequence or a spread spectrum signal obtained by multiplying transmission data and a spread spectrum code sequence. Two systems of spread spectrum signals in which signal channels and observation channels alternate are provided, and two orthogonally modulated carriers are modulated by two modulation signals whose timings are controlled so that the two signal channels do not overlap with each other. In the demodulator on the receiving side for transmitting and receiving the signal, the timing relationship of the two systems for each of the orthogonal detection axis outputs, the timing of the transmitting side being returned to that before the control, is the spectrum spreader according to the invention of claim 1. The operation is the same as that described for one system of the communication device. By having a free signal waveforms temporally output null section, there is an effect that alleviates the envelope variation accompanying insertion of the observation channel. The spread spectrum communication apparatus according to claim 3 includes at least one of the modulation units M1 and M2 of the spread spectrum communication apparatus according to claim 1 and claim 2 and has been described. The spread spectrum communication apparatus according to claim 4 is based on claims 1 and 2.
Demodulation units D1, D2 of the spread spectrum communication apparatus in
It is provided with at least one of D3 and D4, and has already been described.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 8 of the modulator of the spread spectrum communication apparatus according to the first aspect of the present invention will be described below.
Next, the ninth to fourteenth embodiments of the demodulation unit that receives the transmission signal of the modulated wave output from the modulation unit of the first to eighth embodiments will be described.

Embodiment 1 FIG. FIG. 1 is a block diagram of a modulator of a spread spectrum communication apparatus according to a first embodiment of the present invention. In the figure, 101 is a transmission data input terminal, 10
2 is a multiplier, 103 is a spread spectrum code generator, 10
5 is an observation channel inserter, 108 is a waveform shaping filter,
109 is a transmission baseband signal, and 110 is a modulator.

Next, the operation will be described with reference to FIGS. 1, 9 and 10. In FIG. 1, an observation channel inserter 1
FIG. 9 shows the output of the spread spectrum code generator 103 in FIG.
The observation channel is inserted into the spread spectrum code sequence 104 shown in FIG. As shown in FIG. 9C, the spread spectrum code sequence 106 into which the observation channel is inserted has two types of channels, ie, a section where a signal is present and a section where no signal is present. A section where no signal exists is called a channel and an observation channel is called an observation channel. As a method of inserting the observation channel, a pulse sequence of the spread spectrum code sequence 104 as shown in FIG.
A method of converting into an RZ (Return to Zero) code pulse sequence 106 shown in FIG.
There is a method of inserting an output zero section for each unit pulse of the spread spectrum code sequence 104 as shown in FIG. 10B and converting it into a pulse sequence 106 shown in FIG. 10C. What is necessary is just to select suitably according to the balance of a spreading code etc., and it does not specifically limit in this invention.

Here, an example is shown in which an M sequence having a sequence length of 7 is used as the spread spectrum code sequence 104 shown in FIGS. 9B and 10B. Further, R shown in FIG.
Z (Return to Zero) code pulse sequence 1
06 shows an example in which the duty ratio of the RZ pulse is 50%. In the pulse sequence 106 shown in FIG. 10C in which the output zero section is inserted for each unit pulse of the spread spectrum code sequence 104, the time width of the output zero section and the time width of the unit pulse of the spread spectrum code sequence 104 are determined. An example in which the values are equal is shown.

The transmission data shown in FIG. 9A input to the modulation section is multiplied by the multiplier 102 with the spread spectrum code sequence 106 into which the observation channel shown in FIG. 9C is inserted. A spread spectrum signal 107 into which the observation channel shown in (d) is inserted is obtained. The spread spectrum signal 107 into which the observation channel is inserted is waveform-shaped by the waveform shaping filter 108 to obtain a modulation signal shown in FIG. 9E, and the modulator 110 modulates, for example, phase shift keying (hereinafter, referred to as PSK). Then, a PSK modulated wave is output. In the case of another method for inserting the observation channel, the transmission data shown in FIG.
The product is multiplied by the multiplier 102 with the spread spectrum code sequence 106 into which the observation channel shown in FIG.
A spread spectrum signal 107 into which the observation channel shown in (d) is inserted is obtained. The spread spectrum signal 107 into which the above-described observation channel is inserted is waveform-shaped by a waveform shaping filter 108 to obtain a modulation signal shown in FIG. 10E, and is modulated by, for example, PSK by a modulator 110 to output a PSK modulated wave. Here, the waveform shaping filter may be replaced with a low-pass filter having a sufficient band for passing a signal component (baseband component) unless it is particularly necessary to limit the signal band on the transmission side. Good or omitted.

The demodulation unit for receiving and demodulating the transmission signal of the modulated wave output from the modulation unit shown in the first embodiment is shown in FIGS. 11 and 16 showing the ninth and twelfth embodiments as described later.
And can suppress the interference wave component included in the detection signal.

Embodiment 2 FIG. FIG. 2 is a block diagram showing a modulator of a spread spectrum communication apparatus according to a second embodiment of the present invention. Transmission data and spread spectrum code sequence 10
4 is multiplied by the multiplier 102 to obtain a spread spectrum signal 111, and then the observation channel is inserted into the above spread spectrum signal by the observation channel inserter 105, as in the first embodiment. On the receiving side, as will be described later, the configuration of the demodulation units in FIGS. 11 and 16 showing the ninth and twenty-first embodiments can suppress the interference wave component included in the detection signal.

Embodiment 3 FIG. Third Embodiment FIG. 3 is a block diagram of a modulator of a spread spectrum communication apparatus according to a third embodiment of the present invention. In the figure, 151 is a second transmission data input, 1
53 is a second spread spectrum code generator, and 155 is a second spread spectrum code generator.
158 is a second waveform shaping filter, and 120 is a quadrature modulator. The difference from the first embodiment is as follows.
The multipliers 102 and 152 multiply the two transmission data and the two systems of spread spectrum code sequences 106 and 156 with the observation channel inserted therein to obtain two systems of spread spectrum signals 107 and 157 with the observation channel inserted. After the respective waveforms are shaped, the orthogonal modulator 120 modulates mutually orthogonal carriers to obtain a transmission signal. Here, the quadrature modulator 120 multiplies, for example, each of the two modulation signals, one of the outputs of the carrier wave oscillator, and the other with the output of the above-described carrier wave oscillator phase-shifted by a π / 2 phase shifter. It is composed of an adder that performs analog addition.

The demodulation unit for receiving and demodulating the transmission signal of the modulated wave output from the modulation unit shown in the third embodiment is a demodulation unit shown in FIG. 12 showing the tenth embodiment described later or FIG. 19 showing the thirteenth embodiment. It is a demodulation unit and can suppress an interference wave component included in the detection signal.

Embodiment 4 FIG. FIG. 4 is a block diagram of a modulator of a spread spectrum communication apparatus according to a fourth embodiment of the present invention. The difference from the second embodiment is that the same operation as in the second embodiment is performed for each of the two transmission data, and the two systems of spread spectrum signals 107,
157, and after waveform shaping, quadrature modulator 1
20 is configured to modulate orthogonal carrier waves to obtain a transmission signal. The signal waveforms at various points in FIG. 4 are shown in FIGS. 26 (a), (b), (c), (d) and (f). As shown in FIG. 26 (f), at the output of the quadrature modulator 120, four-phase shift keying (hereinafter, QPSK)
) Signal and an observation channel are obtained alternately. Here, the effects of the waveform shaping filters 108 and 158 are omitted, and the quadrature modulator 120
Are decomposed into respective orthogonal axes.

The demodulation unit for receiving and demodulating the transmission signal of the modulated wave output from the modulation unit shown in the fourth embodiment is similar to the third embodiment shown in FIG. FIG. 19 is a demodulator of FIG. 19 showing Example 13, and can suppress an interference wave component included in a detection signal.

Embodiment 5 FIG. FIG. 5 is a block diagram of a modulator of a spread spectrum communication apparatus according to a fifth embodiment of the present invention. The difference from the third embodiment described above is that one transmission data is divided into two spread spectrum code sequences 104 and 1 having an independent phase difference or a constant phase difference from each other.
54, the same operation as in the third embodiment is performed, and two systems of spread spectrum signals 107 and 1 into which an observation channel is inserted.
After obtaining the signal 57 and shaping the waveform, the orthogonal modulator 120 modulates the mutually orthogonal carriers to obtain a transmission signal. The demodulation unit for receiving and demodulating the transmission signal of the modulated wave output from the modulation unit shown in the fifth embodiment is a demodulation unit shown in FIG. 13 showing the eleventh embodiment described later or FIG. 20 showing the fourteenth embodiment. Yes, it is possible to suppress the interference wave component included in the detection signal. Example 1,
2, a spread spectrum communication apparatus having a large spread gain can be obtained as compared with the case of the first system.

Embodiment 6 FIG. FIG. 6 is a block diagram of a modulator of a spread spectrum communication apparatus according to a sixth embodiment of the present invention. The difference from the fourth embodiment described above is that one transmission data is divided into two spread spectrum code sequences 104 and 1 having an independent phase difference or a fixed phase difference from each other.
54, the same operation as in the fourth embodiment is performed, and two systems of spread spectrum signals 107 and 1 into which an observation channel is inserted.
After obtaining the signal 57 and shaping the waveform, the orthogonal modulator 120 modulates the mutually orthogonal carriers to obtain a transmission signal.

FIG. 26 shows the signal waveform of each section of the modulation section shown in FIG.
(A), (b), (c), (d) and (f) are shown. FIG.
As shown in FIG. 6 (f), at the output of the quadrature modulator 120, Q
A spread spectrum signal in which the PSK signal and the observation channel alternate is obtained. Here, the effects of the waveform shaping filters 108 and 158 are omitted, and the output signal of the quadrature modulator 120 is shown decomposed into each quadrature axis. here,
The method of inserting observation channels by observation channel inserters 105 and 155 is an example in which pulses of spread spectrum signals 111 and 161 are converted into RZ codes, and spread spectrum code sequences 104 and 154 use M sequences having a sequence length of 7. An example is shown. The demodulation unit that receives and demodulates the transmission signal of the modulated wave output from the modulation unit is described in Example 11 described later.
13 or FIG. 20 showing the fourteenth embodiment, and can suppress an interference wave component included in a detection signal. As compared with the case of one system of Embodiments 1 and 2,
A spread spectrum communication apparatus having a large spread gain can be obtained.

Embodiment 7 FIG. FIG. 7 is a block diagram of a modulator of a spread spectrum communication apparatus according to a seventh embodiment of the present invention. The configuration is the same as that of the third embodiment described above, except that the same spread spectrum code sequence 104 is used for two pieces of transmission data to obtain two systems of spread spectrum signals 107 and 157 into which an observation channel is inserted. After the shaping, the orthogonal modulator 120 modulates mutually orthogonal carriers to transmit a transmission signal. The demodulation unit that receives and demodulates the transmission signal of the modulated wave output from the modulation unit is the demodulation unit illustrated in FIG. 12 illustrating the tenth embodiment described later or FIG. 19 illustrating the thirteenth embodiment. The two systems of matched filters, in the thirteenth embodiment, the two systems of channel matched filters each hold the same spread spectrum code sequence as the transmission side, so that the interference wave component included in the detection signal can be suppressed. .

Embodiment 8 FIG. FIG. 8 is a block diagram of a modulator of a spread spectrum communication apparatus according to an eighth embodiment of the present invention. The configuration is the same as that of the fourth embodiment described above, except that the two transmission data are spread using the same spread spectrum code sequence 104. The operation is also similar to that of the fourth embodiment except for the above components.
Is the same as The demodulation unit for receiving and demodulating the transmission signal of the modulated wave output from the modulation unit is the same as that in the seventh embodiment.

Although not shown in FIG. 1 to FIG. 8, it goes without saying that the timing relationship among the transmission data, the spread spectrum code generator and the observation channel inserter is all controlled by the control clock. In the third, fourth, seventh, and eighth embodiments using a spread spectrum signal into which two observation channels are inserted, one of the systems is for data modulation, and the other is for transmission of a pilot signal. > Can also be used for

Next, embodiments 9 to 14 of the demodulation unit of the spread spectrum communication apparatus according to the present invention will be described. The demodulation unit receives and demodulates the transmission signal of the modulated wave output from the modulation unit of the spread spectrum communication apparatus according to the first to eighth embodiments described above.

Embodiment 9 FIG. FIG. 11 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to a ninth embodiment of the present invention. A demodulation unit for receiving and demodulating a transmission signal of a modulated wave output from the modulation unit of the spread spectrum communication apparatus of FIGS. In the figure, 301
Is a terminal to which a detection signal is input, 302 is a waveform shaping filter, 304 is a sampler, and 306 is a serial-parallel converter (hereinafter, referred to as a serial-parallel converter).
S / P converter), 307 is a signal channel sample value, 308 is an observation channel sample value, 309 is a delay unit, 310 is an interpolation estimator, 312 is an interpolation estimation value of an interference wave included in a signal component, and 313 is A canceler 315 is a matched filter, 317 is a data decision unit, and 318 is a demodulated data output terminal. Although not shown in the figure, these components are controlled by a control clock, and the control clock is performed by a timing recovery system using a matched filter output. The timing reproduction system is constituted by, for example, a conventionally used DLL (delay lock loop).

Next, the operation will be described with reference to FIGS. FIG. 14 is a diagram for explaining an interference wave suppressing operation of the demodulation unit of the spread spectrum communication apparatus of FIG.
FIG. 14A is a diagram showing the vector trajectory of the interference wave included in the received signal with time. Here, the relationship between the signal and the interference wave is the same as that shown in FIG. 32 in the description of the conventional technique. That is, the signal component is included only in the in-phase axis, the power of the interference wave is 100 times (10 times in voltage ratio) the carrier power (carrier peak power) in the section where the signal exists, and the interference wave and the signal wave An example in which the difference between the center frequencies is {(π / 4) / 7} · Ts (where Ts is a transmission data interval) will be described. In addition, the time ratio between the signal channel and the observation channel is set to 1: 1. For convenience of explanation, the influence of the band limitation is omitted here. FIG.
FIG. 14B shows the in-phase axis I of the interference wave vector shown in FIG.
And the component of the orthogonal axis Q. The rectangular pulse train in FIG. Here, the amplitude of the signal component is +1 or -1, and is shown scaled 10 times in the figure.
The in-phase axis component shown in FIG. 14C is input to the input terminal 301 in FIG. () Shown in the vector of FIG.
The numerical values in the parentheses are the amplitude values of the in-phase axis components of the interference wave.
As can be seen from FIG. 14C, the signal channel includes the signal and the interference wave component, and the observation channel includes only the interference wave component.

Next, the signal channel and the observation channel of the detection signal are sampled by the sampler 304, and the sample value of the signal channel is sampled by the S / P converter 306 to the delay unit 30.
9, the sample values of the observation channel are output to the interpolation estimator 310. This can be realized by a 1-bit / 2-bit S / P converter because the signal channel and the observation channel are transmitted alternately. The interpolation estimator 310 is, for example, an adder, a multiplier, or a digital signal processor (DS).
P), and has a CPU and the like , and interpolates and estimates the interference wave component included in the sample value of the signal channel from the interference wave component sample value of the observation channel. As an interpolation estimation method, linear interpolation will be described as an example. Linear interpolation is a method in which an average value of interference wave component sample values of observation channels before and after a signal channel is used as an estimated value of an interference wave component included in the signal channel. Now, the estimated value of the interference component 3302 included in the signal component 3304 in FIG.
It is given by the average value of 303 and becomes the next value. (9.2 + 3.8) /2=6.5 Interference wave components included in other signal channels are similarly estimated by interpolation. The delay unit 309 holds the sample value of the signal channel until the interpolation estimated value is output.

The canceller 313 has an adder that includes a code shown in the figure and performs addition, and subtracts the interpolated estimated value of the interference wave component from the sample value of the signal channel.
FIG. 14D shows each component input to the canceller 313. The black vector shown in FIG. 14D indicates the interference wave component included in each signal channel, and the white vector indicates the interpolated estimated value of the interference wave component included in the signal channel described above. Therefore, at the canceller output 314, the interference wave component included in the previous signal channel 3304 is suppressed and becomes the next value. 7.1-6.5 = 0.6 Similarly, in the canceler output 314, FIG.
As shown in (1), the interference wave component included in the signal channel is effectively suppressed. Numerical values in parentheses in each signal channel of FIG. 14E indicate interference wave components of the output of each canceller.

The canceler output 314 further performs a correlation detection by a matched filter 315 using the same spread spectrum code sequence as that on the transmitting side. FIG. 15 shows an example in which a digital matched filter whose internal configuration is shown in FIG. 15 is used as the matched filter 315. In FIG.
The memory 3150 holds the same spread spectrum code sequence as that on the transmitting side. The delay unit 3151 outputs the canceller output 3
14, the contents of the memory and the contents of each stage of the delay device are multiplied by multipliers 3152 to 3158,
The outputs of the multipliers are summed by an adder 3159 and output to a terminal 316. Numerical values in parentheses shown in FIG. 14F indicate output values of the multipliers 3152 to 3158 in FIG. 15, respectively. Accordingly, the sum of the outputs of the respective multipliers by the adder 3159 becomes the following value, and it can be seen that the interference wave component is effectively suppressed. 0.8 (interference component) +7.0 (signal component) Finally, the data determination unit 317 determines transmission data, and obtains demodulated data at the output terminal 318. Example 9
Since the interference wave is suppressed before the correlation detection, there is an advantage that the load on the matched filter 315 can be reduced and the dynamic range can be relatively widened.

Although the influence of the band limitation is omitted in FIG. 14, for example, the waveform shaping filter 108 in FIG. 1 of the modulator on the transmitting side and the waveform shaping filter 302 in FIG. Is such that the Nyquist condition is satisfied with respect to the unit pulse length T ₀ , the two are mutually banded at the center point of the signal channel and the observation channel.
Since the influence of the area limitation is not exerted, the concept of FIG. 14 can be applied as it is.

In the ninth embodiment, an example using a digital matched filter whose internal configuration is shown in FIG. 15 as the matched filter 315 in FIG. 11 has been described. However, the present invention is not limited to this. May be used. For example, Kazuo Tsubouchi: "Applications and Devices of Spread Spectrum Communication", IEICE Transactions, Vo
l. J74-B2 No. 5, (1991.5).
Further, an example in which linear interpolation is used as the interpolation method of the interpolation estimator 310 has been described. However, the present invention is not limited to this, and another interpolation method may be used. For example, Jiro Yamauchi, Shigeru Moriguchi and Shin Ichimatsu: “Numerical calculation method 1 for electronic computers”, Baifukan (1970.9) pp. It is also realized by using a numerical calculation algorithm such as Lagrange interpolation and Aitkin interpolation shown in FIGS.

Embodiment 10 FIG. FIG. 12 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to Embodiment 10 of the present invention. A demodulation unit for receiving and demodulating a transmission signal of a modulated wave output from the modulation unit of the spread spectrum communication apparatus of FIGS. 3 and 4 showing the third and fourth embodiments, respectively.
The demodulation unit having the configuration shown in FIG. 11 showing the ninth embodiment described above has two demodulators, one for the in-phase axis and one for the orthogonal axis
The in-phase component and the quadrature-axis component of the detection signal are input to the input terminals 301 and 351 respectively, and the interference wave components included in the signal channels of the in-phase axis and the quadrature axis are operated in the same manner as in the ninth embodiment. Can be suppressed.
Also, in the seventh and eighth embodiments, the spread spectrum signals generated and transmitted by the modulators of the spread spectrum communication apparatuses shown in FIGS. Is configured as shown below, it is possible to suppress the interference wave component included in the detection signal. That is, the two matched filters 315 and 365 of the demodulation unit shown in FIG. 12 are both configured to hold the same spread spectrum code sequence in the memory on the transmission side and perform correlation detection.

Embodiment 11 FIG. FIG. 13 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to an eleventh embodiment of the present invention. FIGS. 5 and 6 show Examples 5 and 6, respectively.
6 is a demodulation unit that receives and demodulates a transmission signal of a modulated wave output from the modulation unit of the spread spectrum communication apparatus of No. 6. The configuration is the same as that of the tenth embodiment already described and shown in FIG. 12, except that in this case, the same transmission data is transmitted by two systems of the in-phase axis and the quadrature axis. The same data is obtained from the correlation detection outputs of the matched filters 315 and 365. Therefore, the output of the matched filters 315 and 365 of the two systems is added by the adder 366, and then the demodulated data is obtained by the data decision unit 317. Thus, a spread spectrum communication apparatus having a large spread gain can be obtained.

Embodiment 12 FIG. FIG. 16 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to a twelfth embodiment of the present invention. A demodulation unit for receiving and demodulating a transmission signal of a modulated wave output from the modulation unit of the spread spectrum communication apparatus of FIGS. 1 and 2 showing the first and second embodiments, respectively.
In FIG. 16, reference numeral 406 denotes a channel matched filter that performs correlation detection using the same spread spectrum code sequence as that on the transmission side, 408 denotes a delay device that holds the output of the channel matched filter, and 415 denotes a correlation output from each stage of the delay device. A correlation canceller 417 that suppresses the interference wave component remaining after the detection of the correlation of the signal channel using the detected value is a data determiner 417 that determines the demodulated data with respect to the output of the correlation canceller.

FIG. 17 is an internal configuration diagram of the channel matched filter 406 shown in FIG. Sampler output 304
Is input and the sampler output is temporarily held in the delay unit 4062. 4061 is a memory for holding the same spread spectrum code sequence as the transmitting side, and 4063 to 4069 are memories 4
The multiplier 4070 multiplies the content of the data 061 and the content of each stage of the delay device 4062 by 4070.
This is an adder for summing 69 outputs.

FIG. 18 shows the correlation canceller 41 shown in FIG.
5 is an internal configuration diagram of FIG. Output signals 412 and 41 of each stage of the delay unit 408 are provided to each input terminal of the correlation canceller 415.
3 and 414, and an adder 4150 for adding the above output signals 412 and 414, and an attenuator 4151 for reducing the output of the adder 4150 to half the average value calculator. The output signal of the attenuator 4151 and the output signal 413 of the delay unit 408 are added to the adder 4
The addition is performed in step 152 to obtain an output 416 of the correlation canceller 415.

Next, the operation will be described. FIG. 21 shows FIG.
FIG. 16 is a diagram for explaining an interference wave suppressing operation of a demodulation unit of the spread spectrum communication apparatus of No. 6; Here, the influence of the waveform shaping filter is omitted. FIG. 21A shows the contents of the memory 4061 of the channel matched filter 406 shown in FIG. 17, and stores the same spread spectrum code sequence as that on the transmitting side. Here, an example using an M-sequence with a sequence length of 7 is shown, but the memory 4061,
The number of stages of the delay device 4062 is also set to the number of stages . FIG.
1 (b), (d), and (f) have t = −T ₀ , t = 0, t
= T ₀ indicates the contents of the delay unit 4062 at three times,
21 (c), (e) and (g) show outputs of multipliers 4063 to 4069 (output to adder 4070).
Here, t = 0 corresponds to the reproduction timing generated by the timing reproduction system. Symbols a to g attached to the contents of 4061 in FIG. 21A are the memories 4061 in FIG.
Indicates that it is held in the column marked with.
21 (b), (d) and (f), the interference wave component of the sample value is indicated by a vector, and the spread spectrum signal is indicated by a rectangular pulse. Here, the amplitude of the rectangular pulse train is +1, -1 and is shown scaled by a factor of 10 in the figure. Numerical values in parentheses in the figure indicate the amplitude values of the interference wave components.

In the channel matched filter shown in FIG. 17, every other tap output from the delay unit is configured so that correlation detection can be performed on a spread spectrum signal in which a signal channel and an observation channel exist alternately. This is different from the configuration of the matched filter shown in FIG. Therefore,
As shown in FIG. 21, the output to the adder 4070 is only the digit connected to the multiplier among the contents of the delay device, and 4061
(In this example, the M-sequence having a sequence length of 7) determines the polarity of the content of 4062. Adder 40
At step 70, the outputs of the respective multipliers, including the polarities, are added at the same time to obtain the sum. The sum of each of FIGS. 21 (c), (e), and (g) is as follows. −1.6 (interference wave component) (when t = T ₀ ) 10.0 (interference wave component) +7.0 (signal component) (when t = 0) 20.0 (interference wave component) (t = when -T ₀₎

In FIG. 16, when the channel matched filter output at time t = 0 is held in the stage 410 of the delay unit 408, the digits 411 and 409 hold the channel matched filter outputs at time t = −T ₀ , T _0. Is done. Accordingly, in the correlation canceller 415, with the circuit configuration shown in FIGS. 16 and 18, what is input to the adder 4152 with a positive polarity is 10.0 (interference component) +7.0 (signal component). The input to the 4152 with a negative polarity is {(−1.6) +20.0} (1/2) = 9.2 (interference wave component), and the output of the adder 4152 (the output of the correlation canceller 415) 0.8 (interference wave component) +7.0 (signal component). Therefore, the 10.0 interference waves remaining after the correlation detection at time t = 0 are suppressed to 0.8.
On the other hand, the signal components are not affected by the correlation canceller. The correlation canceller 415 of the twelfth embodiment only needs to operate every time a correlation pulse is generated, and signal processing becomes easier as compared with the ninth embodiment. In the estimation in units of correlation pulses, an averaging operation is included in the correlation pulse itself, so that interference wave components can be accurately removed. Although the influence of the waveform shaping filter is omitted in FIG. 21, for example, the overall characteristics of the waveform shaping filter 108 of the modulator on the transmitting side in FIG. 1 and the waveform shaping filter 302 of the demodulator on the receiving side in FIG. If the characteristic satisfies the Nyquist condition with respect to the pulse length T ₀ , the concept of FIG. 21 can be applied as it is because the signal channel and the observation channel do not affect each other at the sampling time point due to the band limitation .

Embodiment 13 FIG. FIG. 19 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to Embodiment 13 of the present invention. A demodulation unit that receives and demodulates a transmission signal of a quadrature modulated wave output from the modulation unit of the spread spectrum communication apparatus of FIGS. 3 and 4 showing the third and fourth embodiments, respectively. The configuration similar to that of FIG. 16 showing the twelfth embodiment already described is provided with two systems, one for the in-phase axis component and the one for the quadrature axis component of the detected signal. Similarly to 12, the interference wave component included in the signal channel of the detection signal is effectively suppressed.

Embodiment 14 FIG. FIG. 20 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to a fourteenth embodiment of the present invention. A demodulation unit for receiving and demodulating a transmission signal of a modulated wave output from the modulation unit of the spread spectrum communication apparatus of FIGS. The configuration is the same as the configuration of the demodulation unit in FIG. 19 showing the thirteenth embodiment described above. However, in this case, the same transmission data is transmitted on the two systems of the in-phase axis and the quadrature axis on the transmission side.
The two-system correlation cancellers 415 and 465 of the demodulation unit shown in FIG.
The output is the same data. Therefore, the outputs of the two correlation cancellers 415 and 465 are added by an adder 370, and then demodulated data is obtained by a data determiner 317. A device can be obtained.

Hereinafter, embodiments 15 to 18 of the modulator of the spread spectrum communication apparatus according to the second aspect of the present invention will be described. Next, embodiments 19 and 20 of the demodulation unit for receiving and demodulating the transmission signal of the modulated wave output from the modulation unit will be described.

Embodiment 15 FIG. FIG. 22 is a block diagram of a modulator of a spread spectrum communication apparatus according to Embodiment 15 of the present invention. The difference from the block configuration diagram of the modulator of FIG. 4 showing the fourth embodiment of claim 1 is that a timing offsetter 201 having a delay unit is newly provided to observe one of the two systems of the modulator. The spread spectrum signal 157 into which the channel is inserted is delayed by a time corresponding to the control amount.

Next, the operation will be described with reference to FIGS. FIG. 26 is a diagram for explaining the operation of the modulation unit in FIG. 22, and shows the waveforms of each unit of the modulation unit in FIG. Here, spread spectrum code sequences 104 and 154
As an example using an M sequence having a sequence length of 7,
As an observation channel insertion method of observation channel insertion circuits 105 and 155, unit pulses of spread spectrum signals 111 and 161 shown in FIGS. 26A and 26B are converted into RZ codes having a duty ratio of 50%, respectively. FIG.
An example is shown in which the pulse trains are shown in (c) and (d). The timing offsetter 201 generates the spread spectrum signal 157 into which the observation channel shown in FIG.
Are offset by T ₀ as shown in FIG. 26 (e), and the spread spectrum signals 107 and 207 into which the two observation channels shown in FIGS. 26 (c) and (e) are inserted.
Are not simultaneously present with each other.
The spread spectrum signals 107 and 207 into which the two observation channels shown in FIGS. 26 (c) and (e) are inserted are modulated by the quadrature modulator 120 via the waveform shaping filters 108 and 158, respectively. I do.

The output of the quadrature modulator 120 is shown in FIG.
, The carrier axes are orthogonal to each other, and there is always one of two signal channels in time, and the output of the quadrature modulator 120 of FIG. Unlike FIG. 26 (f) shown in FIG. 26, a transmission waveform having no output zero section is obtained. Here, the effect of the waveform shaping filter is omitted, and the output waveform of the output terminal 210 is decomposed into orthogonal components. As described above, the demodulation unit for receiving and demodulating the transmission signal of the modulated wave output from the modulation unit according to the fifteenth embodiment includes the demodulation units shown in FIGS. 27 and 29 showing the nineteenth and twentieth embodiments as described later. And can suppress the interference wave component included in the detection signal. In particular, since the signal is a spread spectrum signal in which a signal channel always exists in time, the influence of the non-linearity of the amplifier due to the envelope fluctuation due to the insertion of the observation channel is suppressed, and the anti-interference characteristic is obtained.

The offset amount of the timing offsetter 201 may be any value as long as the signal channel and the observation channel are alternated. In the case of FIG. 26 (g), the offset amount may be an integral multiple of T _0. The offset amount is not particularly limited in the present invention. Note that when the timing offset amount is equal to or longer than the transmission data interval Ts, an effect of interleaving between two transmission data, that is, an effect of converting a burst-like error into a random error can be expected. Also, the observation channel insertion circuit 105, 1
It goes without saying that the same object can be achieved by inserting an output zero section having a Tc time width for each unit pulse of the spread spectrum signal as the insertion method of 55.

Embodiment 16 FIG. FIG. 23 is a block diagram of a modulator of a spread spectrum communication apparatus according to a sixteenth embodiment of the present invention. The difference from the block configuration diagram of the modulator of FIG. 3 showing the third embodiment of claim 1 is that a timing offsetter 201 is newly provided and one observation channel of the two systems of the modulator is inserted. The spread spectrum signal is delayed by a time corresponding to the control amount. The output of the quadrature modulator 120 is the same as in the fifteenth embodiment,
The carrier waves shown in FIG. 26 (g) are orthogonal to each other, and there is always one of the two signal channels in time, and the transmission signal has no output zero section, and has the same advantages as the fifteenth embodiment. . The demodulation unit that receives and demodulates the transmission signal of the modulated wave output from the modulation unit as described above includes the demodulation units shown in FIGS.
9 is a demodulation unit that can suppress an interference wave component included in the detection signal.

Embodiment 17 FIG. FIG. 24 is a block diagram of a modulator of a spread spectrum communication apparatus according to a seventeenth embodiment of the present invention. The difference from the block diagram of the modulator of FIG. 8 showing the eighth embodiment of claim 1 is that a timing offsetter 201 is newly provided and one observation channel of two systems of the modulator is inserted. The spread spectrum signal is delayed by a time corresponding to the control amount. As in the fifteenth embodiment, the output of the quadrature modulator 120 is a transmission signal in which the carrier waves are orthogonal to each other and one of the two signal channels always exists in time and the zero output section does not exist. Has the same advantages as
For the transmission signal as described above, the receiving side according to the first embodiment
In the demodulation units of FIGS. 27 and 29, which show 9 and 20, one spread spectrum code sequence is used for each of the two matched filters and the channel matched filter, so that the interference wave included in the detection signal will be described later. Components can be suppressed.

Embodiment 18 FIG. FIG. 25 is a block diagram of a modulator of a spread spectrum communication apparatus according to the eighteenth embodiment of the present invention. The difference from the block diagram of the modulator of FIG. 7 showing the seventh embodiment of claim 1 is that a timing offsetter 201 is newly provided and one observation channel of the two systems of the modulator is inserted. The spread spectrum signal is delayed by a time corresponding to the control amount. As in the seventeenth embodiment, the output of the quadrature modulator 120 is a transmission signal in which the carrier waves are orthogonal to each other and one of the two signal channels always exists in time and the zero output section does not exist. Has the same advantages as
For the transmission signal as described above, the receiving side according to the first embodiment
In the demodulation units of FIGS. 27 and 29, which show 9 and 20, one spread spectrum code sequence is used for each of the two matched filters and the channel matched filter, so that the interference wave included in the detection signal will be described later. Components can be suppressed.

Embodiment 19 FIG. FIG. 27 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to a nineteenth embodiment of the present invention. This is a demodulation unit that receives and demodulates the transmission signal of the modulated wave output from the modulation unit of the spread spectrum communication apparatus of FIG. 22 illustrating the fifteenth embodiment described above or FIG. 23 illustrating the sixteenth embodiment.
Since the two signal channels are transmitted by mutually orthogonal carriers, a two-system configuration that operates on the in-phase axis and the orthogonal axis of the detection signal is provided. Since two signal channels are transmitted from the transmitting side so that they do not overlap with each other in time, the timing is controlled by a newly provided timing offsetter 519, and FIG. Alternatively, the mutual time relationship between the two signal channels before the control by the timing offsetter 201 of FIG. FIG. 28 is a diagram for explaining the operation of suppressing interference waves by the demodulation unit of the spread spectrum communication apparatus of FIG. FIG. 28A shows a detection signal of a received signal, in which an interference wave is mixed in the signal wave components of the in-phase axis (I axis) and the quadrature axis (Q axis). Here, the influence of the waveform shaping filter is omitted. Here, the timing relationship between the two signal channels is the same as that shown in FIG. 26 (g), and shows an example in which the timing of the spread spectrum signal with the orthogonal axis observation channel inserted is offset by T _0. ing. Further, the interference wave has a sinusoidal shape of 100 times (10 times in voltage ratio) the carrier power (carrier peak power) of the signal, and the difference between the center frequencies of the interference wave and the signal wave is ｛(π / 4) /
7｝ · Ts (where Ts is the transmission data interval) is shown. The amplitude of the rectangular pulse train representing the signal wave component is +1 or -1.
The figure shows a result of scaling by a factor of two. FIG. 28 (b)
Shows the sample output of the detected signal by the first sampler of the in-phase axis component, and FIG. 28C shows the sample output of the quadrature axis component of the detected signal by the second sampler. FIG.
FIG. 2D shows a state in which the sample output of the first sampler of the in-phase axis component shown in FIG. 28B is offset by T ₀ by the timing offsetter 519.
FIG. 8C shows the result of restoring the time relationship between the data and the sample output of the second sampler of the orthogonal axis component. After the timing offsetter 520 and the second support
The output from the sampler 555 is the same as that of the embodiment described above.
9 is the same as that in
Interference component can be estimated and canceled effectively
You. The operation of the demodulation unit that receives and demodulates the transmission signal of the modulated wave output from the modulation unit of the spread spectrum communication apparatus of FIG. 22 illustrating the fifteenth embodiment or FIG. 23 illustrating the sixteenth embodiment has been described. FIG. 2 showing Example 17
4. For the transmission signal of the modulated wave output from the modulation unit of the spread spectrum communication apparatus of FIG. 25 showing the eighteenth embodiment, the memory of the matched filters 515 and 565 of the two systems of the demodulation unit is the same as the same transmission side. By holding the spread spectrum code sequence, the same can be said for this embodiment.

Embodiment 20 FIG. 29 is a block diagram of a demodulator of a spread spectrum communication apparatus according to Embodiment 20 of the present invention. This is a demodulation unit of another configuration that receives and demodulates the transmission signal of the modulated wave output from the modulation unit of the spread spectrum communication apparatus of FIG. 22 illustrating the fifteenth embodiment described above or FIG. 23 illustrating the sixteenth embodiment. Since the two signal channels are transmitted by mutually orthogonal carriers, a two-system configuration that operates on the in-phase axis and the orthogonal axis of the detection signal is provided. Since the two signal channels are transmitted from the transmitting side so as not to overlap with each other in time, a newly provided timing offsetter 519 is provided.
The timing relationship is controlled in accordance with the relationship between the two signal channels before being controlled by the timing offsetter 201 in FIG. 22 showing the fifteenth embodiment of the transmitting-side modulator or FIG. 23 showing the sixteenth embodiment. return. The operation up to the timing offsetter 519 is the same as the operation in FIG. 29 showing the nineteenth embodiment, and the signal waveforms of the respective parts shown in FIGS. 28 (a), (b) and (c) are also the same. The configurations after the timing offsetter output 520 and after the second sampler output 555 are the same as those of the first and second embodiments shown in FIG.
The configuration after the sampler outputs 305 and 355 is the same as that described above, and the interference wave component remaining after the correlation detection by the channel matched filter is suppressed by the correlation canceller by performing the operation described in detail in the twelfth embodiment for each system. be able to.

Although the influence of the waveform shaping filter is omitted in FIG. 28, the overall characteristics of the waveform shaping filter 108 of the modulator on the transmitting side in FIG. 22 and the waveform shaping filter 502 of the demodulator on the receiving side in FIG. Is such that the Nyquist condition is satisfied with respect to the unit rectangular pulse length T ₀ , the signal channel and the observation channel do not affect each other by the band limitation at the time of sampling, so the concept of FIG. 28 can be applied as it is. .

In the above embodiment, the data modulation method of the signal channels of each system has been described by taking digital phase modulation as an example. However, digital frequency modulation in which the frequency of a carrier is modulated by transmission data, or carrier modulation by transmission data. In the case of digital amplitude modulation that modulates the amplitude of
The same is true.

Although the received signal generally includes thermal noise and the like in addition to the interference wave, the influence of the thermal noise and the like is removed in the correlation detection process according to the spreading gain.

[0060]

As described above, according to the present invention, the following effects can be obtained. In the transmitting-side modulator, an observation channel is inserted to obtain a modulated wave modulated by a spread spectrum signal in which a signal channel and an observation channel are alternately provided. In the receiving-side demodulator, a detection signal of the above-described modulated wave is obtained. Estimate the interference wave component included in the signal channel from the sample value of the observation channel, subtract the estimated value of the interference wave component from the sample value of the signal channel,
Next, the correlation detection is performed by a matched filter, or the detected signal of the modulated wave is subjected to the correlation detection by the channel matched filter, and then the correlation canceller uses the correlation timing to calculate the correlation of the signal channel from the correlation detection value of the signal channel. By subtracting the estimated value of the remaining interference wave component from the detected value, if there is a difference between the center frequencies of the interference wave and the signal wave, the correlation characteristics between the interference wave and the spread spectrum code sequence and the interference wave are further delayed. Even in the case where the correlation characteristics with the spread spectrum code sequence do not match, it is possible to obtain a spread spectrum communication apparatus capable of suppressing an interference wave.

In the modulation section on the transmitting side, the same observation channel is inserted as described above, and two systems of spread spectrum signals in which signal channels and observation channels exist alternately are provided. The timing is controlled so as not to overlap in time, and a modulated wave obtained by modulating a carrier wave orthogonal to each other is obtained. The demodulation unit on the receiving side determines the mutual time relationship between the signal channels for the two systems of the above-described modulated wave detection signals. Return to before the timing control in the modulator,
Estimate the interference wave component included in the signal channel from the sample value of the observation channel for each system, subtract the estimated value of the interference wave component from the sample value of the signal channel, and then perform correlation detection with a matched filter, or By performing a correlation detection on each of the two systems of the modulated wave detection signal using a channel matched filter, and then subtracting an interference wave component remaining in the correlation detection value of the signal channel by a correlation canceller,
Even if there is a difference between the center frequencies of the interference wave and the signal wave, and even if the correlation characteristics between the interference wave and the spread spectrum code sequence do not match the correlation characteristics between the interference wave and the delayed spread spectrum code sequence, , And can suppress interference waves. Furthermore, the modulator output always has a signal channel in time,
Since it has a waveform without an output zero section, it is possible to obtain a spread spectrum communication apparatus capable of suppressing the influence of the non-linearity of the amplifier due to the envelope fluctuation due to the insertion of the observation channel.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a modulator of a spread spectrum communication apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a modulator of a spread spectrum communication apparatus according to a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating a modulator of a spread spectrum communication apparatus according to a third embodiment of the present invention.

FIG. 4 is a block diagram illustrating a modulator of a spread spectrum communication apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram illustrating a modulator of a spread spectrum communication apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram of a modulator of a spread spectrum communication apparatus according to a sixth embodiment of the present invention.

FIG. 7 is a block diagram illustrating a modulator of a spread spectrum communication apparatus according to a seventh embodiment of the present invention.

FIG. 8 is a block diagram illustrating a modulator of a spread spectrum communication apparatus according to an eighth embodiment of the present invention.

FIG. 9 is a diagram for explaining the operation of the modulation unit of the spread spectrum communication apparatus of FIGS. 1 to 8;

FIG. 10 is a diagram for explaining the operation of the modulator of the spread spectrum communication apparatus of FIGS. 1 to 8;

FIG. 11 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to a ninth embodiment of the present invention.

FIG. 12 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to Embodiment 10 of the present invention.

FIG. 13 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to Embodiment 11 of the present invention.

FIG. 14 is a diagram for explaining an interference wave suppressing operation of the demodulation unit of the spread spectrum communication apparatus of FIGS. 11, 12, and 13;

FIG. 15 is an internal configuration diagram of the matched filter of FIGS. 11, 12, and 13;

FIG. 16 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to a twelfth embodiment of the present invention.

FIG. 17 is an internal configuration diagram of the channel matched filter of FIGS. 16, 19, and 20;

FIG. 18 is an internal configuration diagram of the correlation canceller shown in FIGS. 16, 19, and 20;

FIG. 19 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to Embodiment 13 of the present invention.

FIG. 20 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to Embodiment 14 of the present invention.

21 is a diagram illustrating an operation of suppressing interference waves by a demodulation unit of the spread spectrum communication apparatus of FIG.

FIG. 22 is a block diagram of a modulator of a spread spectrum communication apparatus according to Embodiment 15 of the present invention.

FIG. 23 is a block diagram illustrating a modulator of a spread spectrum communication apparatus according to Embodiment 16 of the present invention.

FIG. 24 is a block diagram of a modulator of a spread spectrum communication apparatus according to a seventeenth embodiment of the present invention.

FIG. 25 is a block diagram showing a modulator of a spread spectrum communication apparatus according to Embodiment 18 of the present invention.

26 (a), (b), (c), (d),
(F) is a diagram for explaining the operation of FIGS. 3 to 6.
26 (a), (b), (c), (d), (e),
(G) is a diagram for explaining the operation of FIGS.

FIG. 27 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to Embodiment 19 of the present invention.

28 is a diagram illustrating an operation of suppressing interference waves by a demodulation unit of the spread spectrum communication apparatus of FIG. 27;

FIG. 29 is a block diagram of a demodulation unit of a spread spectrum communication apparatus according to Embodiment 20 of the present invention.

FIG. 30 is a block diagram showing a demodulation unit of a conventional spread spectrum communication apparatus.

FIG. 31 is a diagram for describing an outline of interference wave suppression of the spread spectrum communication apparatus of FIG. 30;

FIG. 32 is a diagram illustrating an operation of suppressing interference waves by a demodulation unit of the spread spectrum communication apparatus of FIG. 30;

[Explanation of symbols]

Reference Signs List 102 multiplier (first multiplier) 103 spread spectrum code generator (first spread spectrum code generator) 105 observation channel inserter (first observation channel inserter) 108 waveform shaping filter (first waveform shaping) Filter) 110 modulator 152 second multiplier 153 second spreading code generator 155 second observation channel inserter 158 second waveform shaping filter 120 quadrature modulator 201 timing offsetter 302 waveform shaping filter (first Waveform shaping filter) 304 Sampler (first sampler) 306 S / P (serial-parallel converter) (first S / P) 309 Delayer (first delayer) 310 Interpolation estimator (first interpolation estimation) 313 canceller (first canceller) 315 matched filter (first matched filter) 317 data decision unit (first 1 data decision unit) 352 second waveform shaping filter 354 second sampler 356 second S / P (serial-parallel converter) 359 second delay unit 360 second interpolation estimator 363 second canceller 365 Second matched filter 367 Second data determiner 370 Adder 3150 Memory 3151 Delayer 3152 to 3158 Multiplier 3159 Adder 406 Channel matched filter (first channel matched filter) 4061 Memory 4062 Delayer 4063 to 4069 Multiplier 4070 Adder 408 Delay unit (first delay unit) 415 Correlation canceller (first correlation canceller) 456 Second channel matched filter 458 Second delay unit 465 Second correlation canceller 502 First waveform shaping filter 504 First sampler 506 First S / P (serial-parallel converter) 509 first delay unit 510 first interpolation estimator 513 first canceller 515 first matched filter 517 first data decision unit 519 timing offsetter 552 second waveform Shaping filter 554 Second sampler 556 Second S / P (serial / parallel converter) 559 Second delay unit 560 Second interpolation estimator 563 Second canceller 565 Second matched filter 567 Second data determination 606 First channel matched filter 608 First delay unit 615 First correlation canceller 656 Second channel matched filter 658 Second delay unit 665 Second correlation canceller

Claims (4)

(57) [Claims] 1. A spread spectrum communication apparatus that spreads transmission data from a transmission side and transmits the data, and a reception side performs correlation detection on a detection signal using the same spread spectrum code sequence as that of the transmission side and demodulates the transmission data. A modulation unit having the following elements is denoted by M1, and demodulation units are denoted by D1 and D2.
M1 and a spread spectrum communication apparatus comprising at least one of D1 and D2; (a) a modulation section M1 having the following elements: (a1) a spread spectrum code generator for generating a spread spectrum code sequence (A2) a multiplier for multiplying transmission data and the above-mentioned spread spectrum code sequence to obtain a spread spectrum signal; (a3) the above spread spectrum code sequence or an observation channel for inserting an observation channel into the above spread spectrum signal Insertion means, (a4) a waveform shaping filter for shaping the spread spectrum signal into which the observation channel is inserted, (a5) a modulator for multiplying the output of the waveform shaping filter and a carrier to obtain a modulated wave, (b) (B1) a waveform shaping filter for shaping the waveform of the detection signal; (b2) a waveform shaping filter output from the above. (B3) a serial-to-parallel converter that classifies the sampler output into observation channel sample values and signal channel sample values, (b4) an interference wave component mixed into the signal channel from the observation channel sample values (B5) a canceller for subtracting the estimated value of the interference wave component from the signal channel sample value, and (b6) an output of the canceller using the same spread spectrum code sequence as that on the transmitting side. (B8) a data determinator that determines transmission data for the matched filter output, (c) a demodulation unit D2 having the following elements, (c1) a waveform shaping filter that shapes the waveform of a detection signal, c2) a sampler for sampling the output of the waveform shaping filter, and (c3) a sampler for the output of the sampler. (C4) a delay unit that holds the output of the channel matched filter, (c5) a delay unit that holds the output of the channel matched filter, and (c5) a delay unit that holds the output of the channel matched filter. A correlation canceller that subtracts an interference wave component remaining after signal channel correlation detection using the output correlation detection value; (c6) a data determiner that determines transmission data for the correlation canceler output. 2. A spread spectrum communication apparatus which spreads transmission data from a transmission side and transmits the data, and a reception side performs correlation detection on a detection signal using the same spread spectrum code sequence as the transmission side and demodulates the transmission data. , A modulator having the following elements as M2 and demodulators as D3 and D4,
M2 and a spread spectrum communication apparatus comprising at least one of D3 and D4; (a) a modulation section M2 having the following elements: (a1) a spread spectrum code generator for generating a spread spectrum code sequence (A2) two systems of multipliers for obtaining a spread spectrum signal by multiplying transmission data and the above spread spectrum code sequence, (a3) observing the above spread spectrum code sequence or the two spread spectrum signals (A4) a timing offsetter for controlling one timing so that the signal channels of the spread spectrum signals into which the two systems of observation channels are inserted do not overlap with each other, (a5) Waveform shaping filters for respectively shaping the two systems of spread spectrum signals, (a6) the above two systems (B) a demodulation unit D3 having the following elements: (b1) a waveform shaping of the in-phase axis component and the quadrature axis component of the detection signal, respectively. (B2) a sampler for sampling the output of each of the waveform shaping filters, (b3) a timing offsetter for controlling the time relationship between the sampler output values, and (b4) a sampler output for each of the above. (B5) Estimating means for estimating an interference wave component of a signal channel from each of the above-mentioned observation channel sample values, (b6) each of the above-mentioned signals A canceller for subtracting the above estimated value from the channel sample value; (b7) each of the above keys A matched filter that performs correlation detection on the output of the canceller using the same spread spectrum code sequence as that of the transmitting side, (b8) a data determiner that determines transmission data for each of the matched filter outputs, and (c) a demodulation unit having the following elements: D4, (c1) a waveform shaping filter for waveform shaping the in-phase axis component and the quadrature axis component of the detected signal, (c2) a sampler for sampling the output of each of the waveform shaping filters, and (c3) a waveform shaped for the above. In-phase axis component of the detection signal,
A timing offsetter for controlling the timing relationship between the sample values of the quadrature axis components, (c4) the in-phase axis components and the quadrature axis components whose mutual timing relationships are controlled, using the same spread spectrum code sequence as that on the transmission side. (C5) a delay device that holds the output of each of the above-mentioned channel matched filters, and (c6) a signal channel correlation using the correlation detection value output from each stage of each of the above-mentioned delay devices. A correlation canceller for subtracting interference wave components remaining after detection; (c7) a data determiner for determining transmission data with respect to the correlation canceler output. 3. A spread spectrum communication apparatus which spreads transmission data and transmits the spread spectrum data, wherein a modulation unit having the following elements is defined as M1 and M2 and at least one of M1 and M2 is provided. (A) a modulation unit M1 having the following elements: (a1) a spread spectrum code generator for generating a spread spectrum code sequence; (a2) a product of transmission data and the above spread spectrum code sequence to generate a spread spectrum signal (A3) an observation channel insertion unit that inserts an observation channel into the spread spectrum code sequence or the spread spectrum signal, (a4) a waveform shaping filter that shapes the spread spectrum signal into which the observation channel is inserted, (A5) a modulator for obtaining a modulated wave by multiplying the output of the waveform shaping filter and the carrier wave, ) A modulation unit M2 having the following elements: (b1) a spread spectrum code generator for generating a spread spectrum code sequence; (b2) two systems for multiplying transmission data and the above spread spectrum code sequence to obtain a spread spectrum signal (B3) an observation channel insertion unit for inserting an observation channel into the above-mentioned spread spectrum code sequence or the above-mentioned two systems of spread spectrum signals, and (b4) a spread spectrum into which the above-mentioned two observation channels are inserted. (B5) a waveform shaping filter that shapes each of the two systems of spread spectrum signals so that the signal channels of the signals do not temporally overlap each other; A quadrature modulator that modulates mutually orthogonal carriers using a waveform shaping filter output as a modulation signal. 4. A spread spectrum communication apparatus for demodulating transmission data by performing correlation detection on a detection signal using the same spread spectrum code sequence as that on the transmission side, comprising a demodulation unit having the following elements: D1, D2, D3, D4 As D1, D
2, a spread spectrum communication apparatus having at least one of D3 and D4, (a) a demodulation unit D1 having the following elements, (a1) a waveform shaping filter for shaping a waveform of a detection signal, (a2) (A3) a serial-to-parallel converter that classifies the sampler output into observation channel sample values and signal channel sample values; (a4) a signal channel from the observation channel sample values (A5) a canceller for subtracting the estimated value of the interference wave component from the signal channel sample value, (a6) the same spread spectrum as the transmission side of the canceller output from the transmission side A matched filter for detecting a correlation using a code sequence; (a7) transmitting data for the matched filter output (B) a demodulation unit D2 having the following elements: (b1) a waveform shaping filter for shaping the waveform of a detection signal; (b2) a sampler for sampling the output of the waveform shaping filter; (B4) a delay unit that holds the output of the channel matched filter, and (b5) a delay unit that holds the output of the channel matched filter. A correlation canceller for subtracting an interference wave component remaining after signal channel correlation detection using a correlation detection value output from the stage; (b6) a data determiner for determining transmission data with respect to the correlation canceler output; (C1) a waveform shaping filter for waveform shaping the in-phase axis component and the quadrature axis component of the detected signal. (C2) a sampler for sampling each of the waveform shaping filter outputs, (c3) a timing offsetter for controlling the time relationship between the sampler output values, and (c4) a sampler output for each of the above sampler outputs. (C5) estimating means for estimating an interference wave component of a signal channel from each of the observed channel sample values; (c6) each of the signal channel samples (C7) a matched filter that performs correlation detection on the output of each of the above cancellers using the same spread spectrum code sequence as that of the transmitting side, and (c8) transmission data on the output of each of the above matched filters. (D) the following elements (D1) a waveform shaping filter for waveform shaping the in-phase axis component and the quadrature axis component of the detection signal, (d2) a sampler for sampling the output of each of the above-mentioned waveform shaping filters, (d3) the above waveform In-phase axis component of the shaped detection signal,
A timing offsetter for controlling the mutual timing relationship between the sample values of the quadrature axis components; (d4) the in-phase axis component and the quadrature axis component whose mutual timing relationships are controlled, using the same spread spectrum code sequence as that on the transmitting side. (D5) a delay device that holds the output of each of the above-mentioned channel matched filters, (d6) a correlation of a signal channel using a correlation detection value output from each stage of each of the above-mentioned delay devices. A correlation canceller for subtracting interference wave components remaining after detection; (d7) a data determiner for determining transmission data for the correlation canceler output.