JPH08251077A - Spread spectrum communication system - Google Patents

Abstract

PURPOSE: To obtain a spread spectrum communication system which can reduce the cost and circuit scale taking advantage of a spread spectrum communication system by a conventional delay multiplexing system and is applicable even when fading is large. CONSTITUTION: The transmitter of a spread spectrum communication system multiplexes and transmits an I signal generated by modulating data spread with delayed spread codes by a modulator 5 and a Q signal generated by modulating only the spread codes by a modulator 7 through a multiplexer 13. A receiver distributes the received signals into two by a distributor 23 and correlates them by a correlator 27 after making one distributed signal into an I1 signal of a base band to obtain an I2 signal. The other distributed signal after being made into a Q1 signal of the base band is correlated by a correlator 31 to obtain a Q3 signal which is delayed by a delay element 39. The I2 signal and Q3 signal are multiplied by a multiplier 40 and the resulting signal is demodulated by a data demodulating circuit 41 into data.

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 system, and more particularly to a spread spectrum communication system using QPSK (quadrature phase modulation) and direct spread.

[0002]

2. Description of the Related Art Generally, communication using a narrow band modulation system is put to practical use for data communication. These can realize demodulation in a receiver with a relatively small circuit, but have a drawback that they are vulnerable to multipath and narrow band colored noise, which is often observed indoors (offices, factories, etc.).

On the other hand, the spread spectrum communication system has an advantage that these drawbacks can be eliminated because the spectrum of data is spread by a spread code and is transmitted in a wide band. However, such a general spread spectrum communication system has drawbacks such that it takes time to reproduce a carrier, a large number of users cannot be secured, and a phase cannot be determined.

Therefore, a spread spectrum communication system based on the delay multiplexing method has been developed. The delay-multiplexing spread spectrum communication system can demodulate the data phase without error without reproducing the carrier, and distinguishes the user by both the delay amount and the spread code. It has advantages such as having many users.

FIG. 13 is a schematic block diagram showing a transmitter in a spread spectrum communication system using such a conventional delay / multiplex method, BPSK (two-phase phase modulation) and direct spread.

Referring to FIG. 13, a transmitter in a conventional spread spectrum communication system includes a data generator 1, a multiplier 3, modulators 5 and 7, a delay element 81, a spread code generator 9,
Local signal generator 85, multiplexer 13, frequency converter 8
3, a power amplifier 17 and a transmission antenna 19.

The multiplier 3 multiplies the data to be transmitted generated by the data generator 1 by the spread code generated by the spread code generator 9. The data generated by multiplying the data generated by the data generator 1 and the spread code will be referred to as multiplication data.

The modulator 5 multiplies the multiplication data from the multiplier 3 by the local signal from the local signal generator 85. Note that BPSK is used in the conventional modulation method of the spread spectrum communication system. Data obtained by multiplying the multiplication data and the local signal by the modulator 5 will be referred to as modulation data. The delay element 81 delays the modulated data from the modulator 5 by an arbitrary number of chips.

On the other hand, the modulator 7 multiplies the spreading code from the spreading code generator 9 by the local signal from the local signal generator 85. Data obtained by multiplying the spread code and the local signal by the modulator 7 will be referred to as a modulated spread code.

The multiplexer 13 multiplexes the modulation data delayed by the delay element 81 and the modulation spread code from the modulator 7. The data multiplexed by the multiplexer 13 will be referred to as combined data. The combined data is the frequency conversion unit 8
After passing through 3, the signal is amplified by the power amplifier 17 and transmitted to the receiver (not shown) by the transmitting antenna 19.

Since the conventional spread spectrum communication system using the delay / multiplex method, BPSK and direct spread is configured as described above, the PDI (Post Detection Int.
The advantage of being able to maximize the effect of egrator), and by combining the delay amount by the delay element 81 and the spread code by the spread code generator 9, many users can be identified.

[0012]

FIG. 14 shows waveforms of signals in a, b, and c of FIG. 13 in the conventional spread-spectrum communication system of FIG. 13, the spread spectrum communication system using BPSK and direct spread. It is a figure.

FIG. 14A shows the waveform of the delayed modulation data in FIG. 13A. FIG. 14B shows
The waveform of the modulation spread code in b of 3 is shown. 14
13C shows the waveform of the combined data in FIG. 13C.

A conventional spread spectrum communication system using the delay multiplexing method and direct spreading uses BPSK and multiplexes two signals modulated by BPSK by the multiplexer 13 in FIG. Therefore, when the phase is shifted by 180 ° as shown in FIG. 14C (T1, T3), the signal is lost. If the phases are not shifted (T
2), an amplitude component appears.

For this reason, the waveform is similar to the on-off keying of ASK (amplitude modulation). That is,
Signal information is present in the amplitude term. Moreover, even if the phase is not completely shifted by 180 °, signal information may exist in the amplitude term.

As described above, the conventional delay / multiplex system, BP
In a spread spectrum communication system using SK and direct spread, signal information exists in the amplitude term, and when a non-linear circuit is used for the power amplifier 17 or the like, the signal (amplitude component) is distorted, which is expensive. There is a problem that it is necessary to use a circuit having a good linear characteristic and the cost becomes high.

In addition, in applications where fading such as indoor propagation is large, a dynamic range of tens of dB is required, and since a non-linear circuit cannot be used for the power amplifier 17 etc., it is difficult to realize an actual circuit. There was a problem.

The present invention has been made in order to solve the above-mentioned problems, and it is a conventional delay / multiplex system, BPS.
An object of the present invention is to provide a spread spectrum communication system in which a nonlinear circuit can be used for a power amplifier and the like, and the cost can be reduced while keeping the advantages of the spread spectrum communication system using K and direct spread.

Another object of the present invention is to provide a spread spectrum communication system which can relax restrictions on the dynamic range and can be applied even in the case of large fading.

Still another object of the present invention is to provide a spread spectrum communication system capable of realizing miniaturization of circuit scale.

Still another object of the present invention is to provide a spread spectrum communication system capable of increasing the throughput of bursty data communication.

[0022]

A spread spectrum communication system according to claim 1 of the present invention comprises transmitting means and receiving means, and the transmitting means comprises means for generating data and at least two predetermined spreading codes. Spreading code generating means for generating one output, and spreading means for spreading the data by the spreading code output to one side of the spreading code generating means to generate spread data, and the other side of the spreading data and the spreading code generating means. One of the spreading codes output is delayed to generate a delay signal on the transmitting side, and the spreading data and the spreading code output to the other side of the spreading code generating means that is not delayed, A quadrature phase modulation means for modulating a side delay signal into an in-phase signal and a quadrature signal whose phases are quadrature, and a transmission signal generation means for transmitting a transmission signal obtained by multiplexing the in-phase signal and the quadrature signal to the receiving means. And a receiving means for distributing the transmission signal into two signals, a converting means for converting the two distributed signals into a baseband in-phase signal and a quadrature signal, respectively, and a baseband In-phase correlation means for outputting an in-phase correlation signal obtained by correlating the in-phase signal and the spreading code, and orthogonal correlation means for outputting an orthogonal correlation signal obtained by correlating the baseband quadrature signal and the spreading code, and in-phase correlation Of the signal and the quadrature correlation signal, the one which is not involved in the delay in the transmission means is delayed by the same time as the delay time in the transmission side to generate the reception side delay signal, and the in-phase correlation signal and the quadrature correlation signal. Of the signals, the one involved in the delay in the transmission means, the multiplication means for multiplying the reception side delay signal to generate a multiplication signal, and the demodulation means for demodulating the data based on the multiplication signal are provided. No.

A spread spectrum communication system according to a second aspect of the present invention comprises a transmitting means and a receiving means, the transmitting means means for generating data and a spreading means for generating a predetermined spreading code on at least two outputs. A code generating means, a spreading means for spreading data by the spreading code output to one side of the spreading code generating means, and generating spread data, and a spreading code and spreading data output to the other side of the spreading code generating means. Quadrature phase modulation means for modulating an in-phase signal and a quadrature signal having quadrature in phase, a transmission-side delay means for delaying one of the in-phase signal and the quadrature signal to generate a transmission-side delay signal, and a transmission-side delay And a transmission signal generating means for transmitting to the reception means a transmission signal obtained by multiplexing a signal and a non-delayed one of the in-phase signal and the quadrature signal, and the reception means divides the transmission signal into two signals. Distributing means, converting means for converting the two distributed signals into a baseband in-phase signal and a quadrature signal, respectively, and an in-phase correlation signal obtained by correlating the baseband in-phase signal and the spread code. An in-phase correlation means, an orthogonal correlation means for outputting an orthogonal correlation signal obtained by correlating a baseband orthogonal signal and a spread code, and one of the in-phase correlation signal and the orthogonal correlation signal which is not involved in the delay in the transmission means. Receiving side delay means that delays by the same time as the delay time at the transmitting side to generate a receiving side delay signal, and one of the in-phase correlation signal and the quadrature correlation signal that is involved in the delay at the transmitting means and the receiving side delay It includes a multiplication unit that multiplies the signal with the signal to generate a multiplication signal, and a demodulation unit that demodulates the data based on the multiplication signal.

A spread spectrum communication system according to claim 3 of the present invention is the spread spectrum communication system according to claim 1 or 2, wherein the demodulating means multiplies a multiplication signal having a time spread within a predetermined time range. A filter that extracts only the signal, an integrating means that integrates the extracted multiplication signal and demodulates the data within a predetermined time range, and one of the in-phase correlation signal and the quadrature correlation signal that does not contribute to the delay in the transmission means as the pilot signal. , And a control means for controlling the filter and the integrating means.

A spread spectrum communication system according to claim 4 of the present invention comprises a transmitting means and a receiving means, and the transmitting means comprises means for generating data and spreading for generating a predetermined spreading code on at least two outputs. The code generating means and the spreading code for spreading the data by the spreading code output to one side of the spreading code generating means to generate the spreading data, and the spreading data and the spreading code output to the other side of the spreading code generating means. The transmitting side delay means for delaying one side and generating the transmitting side delay signal, the spreading data and the spreading code outputted to the other side of the spreading code generating means which are not delayed, and the transmitting side delay signal are phased. A quadrature phase modulation means for modulating a quadrature signal and a quadrature signal which are orthogonal to each other, and a transmission signal generation means for transmitting a transmission signal obtained by multiplexing the in-phase signal and the quadrature signal to the reception means. Is a distribution means for distributing the transmission signal into two signals, a conversion means for converting the two distributed signals into a pseudo baseband in-phase signal and a quadrature signal, respectively, and a pseudo baseband in-phase signal and a spreading signal. In-phase correlation means for outputting an in-phase correlation signal correlated with the code, quadrature correlation means for outputting an orthogonal correlation signal correlated with the quasi-baseband quadrature signal and the spread code, and the in-phase correlation signal on the transmission side And a first receiving-side delay means for generating a first receiving-side delay signal and a quadrature correlation signal for a same time as the delay time.
Second receiving-side delay means for generating a receiving-side delay signal, and first
A first multiplication means for multiplying the reception side delay signal and the quadrature correlation signal to generate a first multiplication signal, and a second multiplication means for multiplying the second reception side delay signal and the in-phase correlation signal to generate a second multiplication signal. And an addition means for adding the first multiplication signal and the second multiplication signal and outputting the addition signal, and a demodulation means for demodulating data based on the addition signal.

A spread spectrum communication system according to a fifth aspect of the present invention comprises a transmitting means and a receiving means, the transmitting means means for generating data and a spreading means for generating a predetermined spreading code on at least two outputs. A code generating means, a spreading means for spreading data by the spreading code output to one side of the spreading code generating means, and generating spread data, and a spreading code and spreading data output to the other side of the spreading code generating means. Quadrature phase modulation means for modulating an in-phase signal and a quadrature signal having quadrature in phase, a transmission-side delay means for delaying one of the in-phase signal and the quadrature signal to generate a transmission-side delay signal, and a transmission-side delay And a transmission signal generating means for transmitting to the reception means a transmission signal obtained by multiplexing a signal and a non-delayed one of the in-phase signal and the quadrature signal, and the reception means divides the transmission signal into two signals. Distributing means, converting means for converting the two distributed signals into a pseudo baseband in-phase signal and a quadrature signal, respectively, and an in-phase correlation signal obtained by correlating the pseudo baseband in-phase signal and the spread code. , A quadrature correlation means for outputting a quadrature correlation signal obtained by correlating a quasi-baseband quadrature signal and a spread code, and And a first receiving side delayed signal is generated.
The receiving side delay means, the second receiving side delay means for delaying the orthogonal correlation signal by the same time as the delay time to generate the second receiving side delay signal, the first receiving side delay signal and the orthogonal correlation signal First multiplication means for multiplying to generate a first multiplication signal;
Second multiplication means for multiplying the reception side delay signal and the in-phase correlation signal to generate a second multiplication signal, addition means for adding the first multiplication signal and the second multiplication signal, and outputting an addition signal, and addition Demodulation means for demodulating data based on the signal.

A spread spectrum communication system according to a sixth aspect of the present invention is the spread spectrum communication system according to the fourth or fifth aspect, wherein the demodulation means adds within a predetermined time range of the addition signals having a time spread. A filter for extracting only the signal, an integrating means for integrating the extracted added signal within a predetermined time range to demodulate the data, and a pilot signal for the in-phase correlation signal and the quadrature correlation signal to control the filter and the integrating means. And control means.

A spread spectrum communication system according to claim 7 of the present invention is the spread spectrum communication system according to any one of claims 1 to 6, wherein the user is distinguished by combining a spreading code and a delay time.

A spread spectrum communication system according to claim 8 of the present invention is the spread spectrum communication system according to any one of claims 1 to 6, wherein the communication area is divided into a plurality of areas, and delay times differ within the same area. Is provided to distinguish a plurality of communication lines, and different spreading codes are used for different areas to distinguish communication lines.

According to a ninth aspect of the spread spectrum communication system of the present invention, in the spread spectrum communication system according to the first to sixth aspects, the communication area is divided into a plurality of areas, and the spreading codes are different in the same area. Then, the communication lines are distinguished, and a plurality of communication lines are distinguished by giving a delay time difference between different areas.

[0031]

In the spread spectrum communication system according to claim 1, the transmitting means comprises: spread data spread by the spread code;
One of the spread data and the spread code that is not delayed is modulated into an in-phase signal and a quadrature signal, and these are multiplexed and transmitted, so that phase modulation is performed and the amplitude component becomes constant.

Further, the receiving means converts the transmission signal transmitted from the transmitting means into a baseband in-phase signal and a quadrature signal, performs correlation with a spread code, and then selects one of the in-phase correlation signal and the quadrature correlation signal. Data is demodulated by multiplying the delayed signal on the receiving side delayed by the one not involved in the delay by the transmitting means by the in-phase correlation signal and the quadrature signal which is involved in the delay by the transmitting means.

In the spread spectrum communication system according to claim 2, the transmitting means modulates the spread data and the spread code spread by the spread code into an in-phase signal and a quadrature signal, and one of the in-phase signal and the quadrature signal. Since the delayed signal on the transmission side, which is delayed, and the undelayed one of the in-phase signal and the quadrature signal are multiplexed and transmitted, phase modulation is performed and the amplitude component becomes constant.

Further, the receiving means converts the transmission signal transmitted from the transmitting means into a baseband in-phase signal and a quadrature signal, performs correlation with a spread code, and then selects one of the in-phase correlation signal and the quadrature correlation signal. Data is demodulated by multiplying the reception side delay signal delayed by the transmitting means that is not involved in the delay and the in-phase correlation signal or the quadrature correlation signal that is involved in the delay by the transmitting means.

In the spread spectrum communication system according to the third aspect, the demodulation means can obtain the in-phase correlation signal or the quadrature correlation signal before integrating the multiplication signal.
Using the pilot signal as a pilot signal, the demodulating means in the receiving means demodulates the data by controlling the predetermined time range of the filter for extracting the multiplication signal in the predetermined time range and the integration by the integrating means.

In the spread spectrum communication system according to claim 4, the transmitting means delays one of the spread data and the spread code spread by the spread code, and the spread signal and the spread code which are not delayed. Since both are modulated into an in-phase signal and a quadrature signal, and they are multiplexed and transmitted, phase modulation is performed and the amplitude component becomes constant.

Further, the receiving means correlates the in-phase correlation signal of the pseudo baseband with the spread code and the first reception side delayed signal obtained by delaying the in-phase correlation signal with the spreading code and the orthogonal signal of the pseudo baseband with the spread code. First multiplied by the orthogonal correlation signal
Data is demodulated by adding the multiplication signal and the second multiplication signal obtained by multiplying the second reception-side delay signal obtained by delaying the orthogonal correlation signal and the in-phase correlation signal.

In the spread spectrum communication system according to claim 5, the transmitting means modulates the spread data and the spread code spread by the spread code into an in-phase signal and a quadrature signal, and one of the in-phase signal and the quadrature signal. Since the delayed signal on the transmission side, which is delayed, and the undelayed one of the in-phase signal and the quadrature signal are multiplexed and transmitted, phase modulation is performed and the amplitude component becomes constant.

Further, the receiving means correlates the in-phase correlation signal of the pseudo baseband with the spreading code and the first reception side delayed signal obtained by delaying the in-phase correlation signal with the spreading code and the orthogonal signal of the pseudo baseband with the spreading code. First multiplied by the orthogonal correlation signal
Data is demodulated by adding the multiplication signal and the second multiplication signal obtained by multiplying the second reception-side delay signal obtained by delaying the orthogonal correlation signal and the in-phase correlation signal.

In the spread spectrum communication system according to the sixth aspect, since the in-phase correlation signal and the quadrature correlation signal can be obtained before the demodulation means integrates the added signal, the demodulation means uses them as pilot signals and the predetermined demodulation means. The data is demodulated by controlling the predetermined time range of the filter for extracting the addition signal in the time range and the integration by the integrating means.

In the spread spectrum communication system of claim 7, by combining the spread code and the delay time,
The number of channels can be increased.

In the spread spectrum communication system according to claim 8, since the communication lines are distinguished by the difference in delay time within the same area and the difference in spreading code between different areas, even if there are few kinds of spreading codes. The division of the communication area can be easily realized.

In the spread spectrum communication system according to claim 9, since the communication lines are distinguished in the same area by the difference of the spread codes and the different areas by the difference of the delay time, there are few kinds of the spread codes. However, division of the communication area can be easily realized.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A spread spectrum communication system according to the present invention will be described below with reference to the drawings.

(First Embodiment) First, in order to show the difference between a spread spectrum communication system using QPSK according to the first embodiment of the present invention and a general spread spectrum communication system using QPSK, A transmitter in a spread spectrum communication system using conventional QPSK will be described.

FIG. 1 is a schematic block diagram showing a transmitter in a spread spectrum communication system using a general QPSK.

In FIG. 1, a transmitter in a spread spectrum communication system using a general QPSK comprises a data generator 1, a serial / parallel (S / P) converter 2, multipliers 3, 6, modulators 5, and 5. 7, a spreading code generator 9, a transmission side local signal generator 11, a multiplexer 13, a transmission side frequency converter 15, a power amplifier 17 and a transmission antenna 19.

The data generated from the data generator 1 is
It is converted into a parallel signal by the S / P converter 2. The multiplier 3 multiplies one of the parallel signals from the S / P converter 2 and the spread code from the spread code generator 9. That is, the multiplier 3 on the other hand spreads the parallel signal by the spreading code. The modulator 5 multiplies one of the spread parallel signals by the cos component from the transmission side local signal generator 11. That is, the modulator 5 modulates one of the spread parallel signals into an in-phase signal (I signal).

The multiplier 6 multiplies the other parallel signal from the S / P converter 2 by the spread code from the spread code generator 9. That is, the multiplier 6 spreads the other parallel signal by the spreading code. The modulator 7 multiplies the other spread parallel signal by the sin component from the transmission side local signal generator 11. That is, the modulator 7 modulates the other spread parallel signal into a quadrature signal (Q signal).

The I signal and the Q signal are multiplexed by the multiplexer 13, passed through the transmission side frequency conversion section 15 and the power amplification section 17, and transmitted by the transmission antenna 19.

As described above, the transmitter of the spread spectrum communication system using the general QPSK spreads the two parallel signals from the S / P converter 2 and converts them into the I signal and the Q signal. Modulate and combine, then transmit.

FIG. 2 is a schematic block diagram showing a transmitter in a spread spectrum communication system using a delay / multiplex system, direct spread and QPSK according to a first embodiment of the present invention.

In FIG. 2, the spread spectrum communication system according to the first embodiment of the present invention includes a data generator 1, a multiplier 3, modulators 5 and 7, a spread code generator 9, a transmission side delay device 10, and a transmission device. Side local signal generator 11, multiplexer 13,
The transmission side frequency conversion unit 15, the power amplifier 17, and the transmission antenna 19 are included.

The data generator 1 generates data to be transmitted. The transmission side delay device 10 delays the spread code generated from the spread code generator 9 by a predetermined delay time. The multiplier 3 includes the data from the data generator 1 and the delay device 1 on the transmission side.
Multiply with the spreading code delayed by 0. That is, the multiplier 3 spreads the data with the delayed spread code.

The modulator 5 multiplies the spread data by the cos component from the transmission side local signal generator 11.
That is, the modulator 5 modulates the spread data into an in-phase signal (I signal).

The modulator 7 multiplies the spread code generated by the spread code generator 9 and the sin component from the local signal 11. That is, the modulator 7 modulates the spread code,
A quadrature signal (Q signal) is used.

The I signal and the Q signal are multiplexed by the multiplexer 13, and transmitted to the receiver (not shown) by the transmitting antenna 19 via the transmitting side frequency converter 15 and the power amplifier 17.

As described above, the transmitter of the spread spectrum communication system according to the first embodiment of the present invention modulates the data spread by the delayed spread code and the spread code into the I signal and the Q signal, respectively. Then, after multiplexing them, they are transmitted.

FIG. 3 is a schematic block diagram showing a receiver in a general spread spectrum communication system using QPSK.

In FIG. 3, the receiver of the spread spectrum communication system using general QPSK is a receiving antenna 21, a receiving side frequency conversion section 22, a distributor 23, and a multiplier 2.
5, 29, correlators 27 and 31, receiving side local signal generator 35, phase detector 37 and data demodulation circuit 38. The data demodulation circuit 38 includes a parallel / serial (P / S) converter (not shown).

The receiving antenna 21 receives the signal from the transmitter.
To receive. The received signal is received by the receiving side frequency conversion unit 22.
Then, it is input to the distributor 23. The distributor 23
Divide the issue into two. The multiplier 25 outputs from the distributor 23
One distribution signal and one from the receiving side local signal generator 35
The cos component and the baseband in-phase signal (I ₁
Signal). I₁The signal is the spreading code used during transmission
Is input to a correlator 27 that can take₂As a signal
Is output.

The multiplier 29 multiplies the other distributed signal from the distributor 23 by the sin component from the receiving side local signal generator 35 and converts it into a baseband quadrature signal (Q ₁ signal). The baseband Q ₁ signal is input to a correlator 31 that can obtain correlation with the spreading code used during transmission, and is output as a Q ₂ signal.

The phase detector 37 detects the carrier phase offset of the signal by using the outputs from the correlators 27 and 31, and controls the receiving side local signal generator 35 by using the control signal CS, thereby performing carrier synchronization. Is taking The data demodulation circuit 38 demodulates the data using the I ₂ signal and the Q ₂ signal from the correlators 27 and 31.

FIG. 4 is a schematic block diagram showing a receiver in a spread spectrum communication system using the delay / multiplex system, direct spread and QPSK according to the first embodiment of the present invention.

In FIG. 4, the receiver of the spread spectrum communication system according to the first embodiment of the present invention comprises a receiving antenna 21, a receiving side frequency converter 22, a distributor 23, multipliers 25 and 29, and correlators 27, 27. 31, reception side local signal generator 35, phase detector 37, delay element 39, multiplier 40
And a data demodulation circuit 41.

The receiving antenna 21 receives a signal from the transmitter shown in FIG. The received signal is input to the distributor 23 via the reception side frequency conversion unit 22. Distributor 23
Splits the signal in two.

The multiplier 25 multiplies one distribution signal from the distributor 23 by the cos component from the reception side local signal generator 35, and converts it into a baseband in-phase signal (I ₁ signal). The baseband I ₁ signal is input to a correlator 27 that can obtain correlation with the spreading code used during transmission, and is output as an I ₂ signal.

The multiplier 29 multiplies the other distributed signal from the distributor 23 by the sin component from the receiving side local signal generator 35, and converts it into a baseband quadrature signal (Q ₁ signal). The baseband Q ₁ signal is input to a correlator 31 that can obtain correlation with the spreading code used during transmission, and is output as a Q ₂ signal.

The Q ₂ signal from the correlator 31 is the delay element 3
By 9, it is delayed by the same time as the delay time by the transmitting side delay device 10 of the transmitter of FIG. 2, the Q ₃ signal.

The phase detector 37 detects the carrier phase offset of the signal by using the outputs from the correlators 27 and 31 and the multiplier 40 which will be described later, and outputs the control signal C.
S is used to control the receiving side local signal generator 35,
The carrier is synchronized. The I ₂ signal from the correlator 27 and the Q ₃ signal from the delay element 39 are multiplied by the multiplier 40 and become a multiplication signal M. The data demodulation circuit 41 demodulates data based on the multiplication signal M.

FIG. 5 shows a receiver of the spread spectrum communication system according to the first embodiment of the present invention shown in FIG.
Of a diagram illustrating the I ₂ signal, Q ₂ signal at b, the waveform of the multiplied signal M at Q ₃ signals and d in c in a.

FIG. 5 (a) shows the waveform of the I ₂ signal in FIG. 4 (a). FIG. 5B shows the waveform of the Q ₂ signal in FIG. 4B. FIG. 5C shows Q ₃ in FIG. 4C.
The waveform of a signal is shown. FIG. 5D shows the waveform of the multiplication signal M in d of FIG.

FIG. 5 shows a signal when the carrier is perfectly synchronized. As shown in FIGS. 5A and 5B, I
_{The 2} signals are the Q ₂ signals, and the transmission side delay device 1 of the transmitter of the spread spectrum communication system according to the first embodiment of FIG.
It is delayed in time by a delay time τ at 0 (time delayed at the transmitting side).

Therefore, as shown in FIG. 5 (c), the Q ₂ signal is delayed by the time τ by the delay element 39 of FIG. 4, so that the timing is the same as that of the I ₂ signal from the correlator 27 of FIG. _You are getting ₃ signals. Then, the multiplier 40 of FIG.
Thus, the I ₂ signal and the Q ₃ signal are multiplied to obtain a multiplication signal M as shown in FIG.

In this case, the I ₂ signal is modulated by both the data from the data generator 1 and the spread code from the spread code generator 9 in the transmitter of the spread spectrum communication system according to the first embodiment of FIG. It is a signal, Q ₃ signal,
Since the signal is modulated only with the spread code, the multiplier 40 in FIG. 4 multiplies them to eliminate the spread code component and output only the data component.

In a general spread spectrum communication system, the number of channels is secured by using a technique called CDMA (code division multiple access), and users are distinguished by the difference in spread codes. However, there are not so many spreading codes with good auto-correlation and cross-correlation, and there are only 6 for m-sequences of 63 chips, for example.

In the present embodiment, as is clear from FIG. 5, the coincidence of the correlation due to the spread code and the output timing from the correlator 27 and the delay element 39 of FIG. 4 are shown in (a) and (c). It can be seen that both coincidence and coincidence result in the multiplication output M as shown in FIG.

That is, even if the same spreading code is used,
If the delay time by the delay element 39 is different, the multiplication output from the multiplier 40 is not output, so that the user can be distinguished also by the delay time. Therefore, the number of channels can be increased by using the two parameters of the spread code and the delay time, and a child having many users can be provided.

As described above, in the spread spectrum communication system according to the first embodiment of the present invention, the transmitter of FIG. 2 uses the same data as the data spread by the delayed spreading code and the non-delayed spreading code, respectively. Since the phase signal (I signal) and the quadrature signal (Q signal) are modulated and then multiplexed and transmitted, phase modulation occurs and the amplitude component becomes constant.

Further, the spectrum according to the first embodiment of FIG.
In the spread spectrum communication system, the receiver of FIG.
The transmission signal transmitted from the transmitter is converted into the baseband in-phase
Signal (I₁Signal) and quadrature signal (Q₁Signal) and send
After correlating with the same spreading code as the transmitter,
Of the quadrature component (Q component) that is not involved in the delay ₂
Q delayed signal₃Involved in delays in the signal and transmitter
I of the in-phase component (I component)₂The signal is multiplied by
Demodulate data.

As a result, in the spread spectrum communication system according to the first embodiment of the present invention, since the amplitude component of the transmission signal from the transmitter becomes constant, a non-linear circuit is used for the power amplifier 17 in FIG. Therefore, the cost can be reduced.

The spread spectrum communication system according to the first embodiment of the present invention is the power amplifier 1 of the transmitter shown in FIG.
By using a non-linear circuit for 7 or the like, the constraint on the dynamic range can be relaxed and it can be applied even when fading is large.

Also, since the number of channels can be increased by combining the spread code and the delay amount, it is possible to have many users. That is, the first aspect of the present invention
Also in the spread spectrum communication system according to the embodiment of the present invention, the advantages of the spread spectrum communication system using the delay multiplexing method and BPSK shown in the conventional technique can be utilized as they are.

The modulation method of the above-mentioned embodiment is the QPSK method, but the MSK method and OQ which are more resistant to nonlinear circuits are used.
Any quadrature modulation method such as the PSK method can be used. Also in this case, the same effect as that of the spread spectrum communication system according to the first embodiment described above is obtained.

Further, in the transmitter of the spread spectrum communication system according to the first embodiment, the transmission side delay device 10 of FIG. 2 can be installed between the multiplier 3 and the modulator 5 or after the modulator 5. . Also in this case, the same effect as that of the spread spectrum communication system according to the first embodiment described above is obtained.

(Second Embodiment) The configuration and operation of the transmitter of the spread spectrum communication system according to the second embodiment are as follows.
It is similar to the configuration and operation of the transmitter shown in FIG. 2 of the spread spectrum communication system in the first exemplary embodiment. Less than,
The transmitter of FIG. 2 will be described as a transmitter of the spread spectrum communication system according to the second embodiment.

FIG. 6 is a schematic block diagram showing a receiver in a spread spectrum communication system using a delay multiplexing method, direct spread and QPSK according to a second embodiment of the present invention.

In FIG. 6, the receiver of the spread spectrum communication system according to the second embodiment of the present invention comprises a receiving antenna 21, a receiving side frequency converting section 22, a distributor 23, multipliers 25 and 29, correlators 27, 31, a reception side local signal generator 35, an I delay element 43, an IQ multiplier 45, a Q delay element 47, a QI multiplier 49, an adder 51 and a data demodulation circuit 41.

The transmission signal from the transmitter of FIG. 2 is received by the reception antenna 21. The received signal is input to the distributor 23 via the reception side frequency conversion unit 22. The distributor 23 divides the received signal into two. Multiplier 2
5 multiplies one of the distribution signals from the distributor 23 and the cos component from the local signal generator 35 to form an in-phase signal (I ₁ signal) of almost baseband (hereinafter referred to as “pseudo baseband”). Convert. This is because they are not perfectly synchronized.

The I ₁ signal of the pseudo baseband is used by the correlator 27 capable of obtaining the correlation with the spreading code used in the transmitter of FIG.
And is output as an I ₂ signal. The I ₂ signal is
The signal is input to the I delay element 43, delayed by the same time as the delay time in the transmitter of FIG. 2, and becomes an I ₃ signal.

The multiplier 29 multiplies the other distribution signal from the distributor 23 by the sin component from the local signal generator 35 to generate a pseudo baseband quadrature signal (Q ₁ signal). The pseudo baseband Q ₁ signal is input to the correlator 31 capable of obtaining the correlation with the spreading code used in the transmitter of FIG. 2 and output as the Q ₂ signal. The Q ₂ signal is delayed by the Q delay element 47 by the same time as the delay time in the transmitter of FIG. 2 to become the Q ₃ signal.

The IQ multiplier 45 multiplies the I ₃ signal from the I delay element 43 by the Q ₂ signal from the correlator 31 to obtain I ₄
Generate a signal. The QI multiplier 49 multiplies the Q ₃ signal from the Q delay element 47 and the I ₂ signal from the correlator 27,
Generate the Q ₄ signal.

The I ₄ signal from the IQ multiplier 45 and the Q ₄ signal from the QI multiplier 49 are added by the adder 51,
The addition signal A is set. The data demodulation circuit 41 demodulates data based on the addition signal A.

FIG. 7 shows an I ₂ signal at a, a Q ₃ signal at b, and a Q _{4 at} c in FIG. 6 in the spread spectrum communication system according to the second embodiment of the present invention.
FIG. 3 is a diagram showing waveforms of a signal, a Q ₂ signal in d, an I ₃ signal in e, an I ₄ signal in f, and an addition signal A in g.

FIG. 7 (a) shows the waveform of the I ₂ signal in FIG. 6 (a). FIG. 7B shows the waveform of the Q ₃ signal in FIG. 6B. FIG. 7C shows Q ₄ in FIG. 6C.
The waveform of a signal is shown. FIG. 7D shows Q in FIG. 6D.
The waveform of _two signals is shown. FIG. 7 (e) shows the waveform of the I ₃ signal in FIG. 6 (e). FIG. 7 (f) shows the waveform of the I ₄ signal in f of FIG. FIG. 7G shows the waveform of the addition signal A in g of FIG.

As shown in FIGS. 7A and 7D, unlike the first embodiment, carrier synchronization is not established in the second embodiment, so that the correlators 27 and 31 of FIG. Output signal (I ₂ signal in FIG. 7A, Q ₂ signal in FIG. 7D)
Contains both the in-phase component (I component) and the quadrature component (Q component) at the time of transmission. Here, the offset with respect to the phase at the time of transmission is θ, and the original amplitude of the output signals from the correlators 27 and 31 of FIG. 6 (when carrier synchronization is established) is A
The following explanation will be given.

As the amplitude of the output signal (I ₂ signal) from the correlator 27 of FIG. 6, Acos θ is shown in (a) of FIG.
In θ appears in θ. On the other hand, as the amplitude of the output signal (Q ₂ signal) from the correlator 31 in FIG. 6, Asin θ appears in C of FIG. 7D and Acos θ appears in D.

The signal I ₃ signal in FIG.
As shown in FIG. 7E, the I ₂ signal shown in FIG.
It is delayed by the delay time τ in the transmitter by the I delay element 43 of. As shown in FIG. 7B, the Q ₃ signal in FIG. 6B is obtained by delaying the Q ₂ signal shown in FIG. 7D by the delay time τ in the transmitter by the Q delay element 47 in FIG. It is a thing.

Here, the IQ multiplier 45 shown in FIG.
Q in FIG. 7 (d)₂Signal and I of (e) ₃Multiply with signal
And I as shown in FIG._FourBecome a signal. This and
I of FIG. 7 (f)_FourThe amplitude of the signal is A²cos²θ
It has become.

The QI multiplier 49 of FIG.
When the I ₂ signal of (a) and the Q ₃ signal of FIG. 7 (b) are multiplied, it becomes like the Q ₄ signal of FIG. 7 (c). At this time, the amplitude of the Q ₄ signal in FIG. 7C becomes A ² sin ² θ.
It should be noted that since the signals C and A involved in the multiplication in FIGS. 7B and 7E are modulated only by the spread code,
The Q ₄ signal in (c) and the I ₄ signal in FIG. 7 (f) are signals modulated only with data.

Here, the adder 51 shown in FIG.
Q in (c)_FourSignal and I in Fig. 7 (f) _FourAnd the signal is added
As a result, the addition signal A as shown in FIG. here
Then, the amplitude of the addition signal A in FIG.²sin²θ + A²cos²θ = A² And the amplitude is always constant.

Generally, the error rate is poor in the asynchronous state,
The error rate can be improved by keeping the amplitude constant, and the modulated wave can be demodulated even in the asynchronous state.

As in the case of the first embodiment, the number of channels can be increased by combining the spread code and the delay amount.

As described above, the space in the second embodiment is
In the Kuttle spread communication system, the receiver of FIG.
6 from the correlator 27 of FIG.
Pseudo-baseband in-phase signal (I₂Signal)
Delayed I₃The signal and correlator 31 from the transmitter of FIG.
Pseudo baseband quadrature signal correlated with the same spreading code
(Q₂I) multiplied by_FourFrom the signal and correlator 31
Quadrature signal (Q₂Q delayed signal)₃Signal and correlator 2
In-phase signal from 7 (I₂Q) multiplied by _FourSignal and
To demodulate the data.

As a result, in the spread spectrum communication system according to the second embodiment, the amplitude of the addition signal A from the adder 51 of FIG. 6 becomes constant, and the error rate is not lowered even though it is in an asynchronous state. Can be demodulated.

Further, since the demodulation can be performed in an asynchronous state, the circuit scale is large and a phase detector and a variable oscillator that require adjustment are unnecessary, and the circuit constituting the spread spectrum communication system can be downsized.

Further, since the synchronization is not established, the time required for the synchronization becomes 0, and the throughput of burst data communication such as packet communication can be increased.

Other effects are similar to those of the spread spectrum communication system according to the first embodiment.

(Third Embodiment) FIG. 8 is a schematic block diagram showing a receiver of a spread spectrum communication system using a delay and multiplexing system, QPSK and direct spread according to a third embodiment of the present invention.

The receiver of the spread spectrum communication system according to the third embodiment of FIG. 8 is the receiver of the spread spectrum communication system according to the first embodiment of FIG. 4 further including a controller 53. Therefore, the operation of the receiver of the spread spectrum communication system according to the third exemplary embodiment is almost the same as that of the receiver of the spread spectrum communication system of FIG. 4 according to the first exemplary embodiment, and the difference will be mainly described. The configuration and operation of the transmitter of this embodiment are the same as the configuration and operation of the transmitter of the first embodiment.

Here, first, PDI (post) for synthesizing signals dispersed by multipath in indoor radio propagation.
A method called detection integration) will be described.

FIG. 9 is a diagram showing waveforms of output signals from the correlators 27 and 31 and the multiplier 40 of FIG. 8 when multipath occurs.

FIG. 9A is a signal from the correlator 27 shown in FIG.
The waveform of the output signal (I ₂ signal) in FIG. Figure 9
8B shows the waveform of the output signal (Q ₂ signal) at b from the correlator 31 in FIG. FIG. 9C shows a multiplier 40.
7 shows a waveform of a multiplication signal M in c to c.

As shown in FIG. 9, multipath occurs in the indoor radio propagation, and the output signals from the correlators 27 and 31 do not have the waveforms shown in FIG. This is because a plurality of waves having different transmission paths arrive at the same time. In a spread spectrum communication system, PDI is used in order to improve the characteristics under such multipath. The PDI is the data demodulator 4 of FIG.
1 is performed using a filter and an integrator (not shown).

First, the filter not shown in FIG.
As shown in FIG. 7, the multiplication signal M from the multiplier 40 of FIG. 8 is taken out for a predetermined time range (t _{1 to} t ₂ ). The predetermined time range (t ₁ ~t ₂₎ the called filtering time window t _FW.

Next, an integrator (not shown) applies the multiplication signal M extracted by the filter to a predetermined time range (t _{1 to} t).
₂ ) Integrate only. By this means, signals spread by multipath can be combined, and the error rate under multipath can be improved.

Under the multi-pass condition, a better C / N may be obtained by adding only a part of the filter time window t _FW and weighting it. However, in general, it is unclear what the multipath state is until the demodulation, so that the processing such as weighting the integral cannot be performed.

In the receiver of the spread spectrum communication system according to the third embodiment of the present invention, as shown in FIG. 9B, before the demodulation timing (earlier than the multiplication output M shown in FIG. 9C). ), The output signal (Q ₂ signal) from the correlator 31 in FIG. 8 can be obtained, so that the weighting of integration and the like can be controlled using the Q ₂ signal as a pilot signal.

Similarly, the filter time window t _FW can be controlled. Such an integration controller that controls integration and a filter time window controller that controls the filter time window are provided in the controller 53 of FIG.

As described above, the spectrum according to the third embodiment is
In the receiver of the Toll spread communication system, the data of FIG.
Before the demodulator 41 integrates the multiplication signal M, FIG.
As shown in, the quadrature signal (Q₂signal)
Can be obtained, so Q ₂Signal as pilot signal
Then, the controller 53 of FIG.
Filter time window t_FWAnd weighting of integration are controlled.

As a result, the effect of PDI can be maximized and the error rate of multipathing can be improved. Other effects are similar to those of the spread spectrum communication system according to the first embodiment.

(Fourth Embodiment) FIG. 10 is a schematic block diagram showing a receiver of a spread spectrum communication system using the delay and multiplexing method, QPSK and direct spread according to the fourth embodiment.

The receiver of the spread spectrum communication system according to the fourth embodiment of FIG. 10 is the receiver of the spread spectrum communication system according to the second embodiment of FIG. 6 further provided with a controller 53. The operation of the receiver of the spread spectrum communication system according to the fourth exemplary embodiment is almost the same as that of the receiver of the spread spectrum communication system according to the second exemplary embodiment. Therefore, the difference will be mainly described. The configuration and operation of the transmitter of this embodiment are the same as the configuration and operation of the transmitter of the first embodiment.

The receiver of the spread spectrum communication system according to the fourth embodiment includes a controller 53 in order to improve the error rate in multipath conversion, like the receiver of the spread spectrum communication system according to the third embodiment. It is provided. The configuration and operation of the controller 53 are the same as those of the third embodiment shown in FIG.
The same as the controller 53 of.

FIG. 11 is a diagram showing waveforms of output signals from the correlators 27 and 31 and the adder 51 of FIG. 10 when multipath occurs.

FIG. 11 (a) is a diagram showing the waveform of the output signal (I ₂ signal) at a from the correlator 27 of FIG. FIG. 11B is a diagram showing the waveform of the output signal (Q ₂ signal) at b from the correlator 31 of FIG. 10. FIG.
1 (c) is a diagram showing the waveform of the addition signal A in c from the adder 51 of FIG.

In the receiver of the spread spectrum communication system according to the fourth embodiment, before demodulation timing (before the addition signal A is processed by the data demodulation circuit 41), as shown in FIGS. As shown, the output signals (I ₂ signal, Q ₂ signal) from the correlators 27 and 31 of FIG.
Therefore, based on the signal (a) in FIG. 11A and the signal (c) in FIG. 11B, the controller 53 causes the filter time window t _FW of the filter (not shown) in the data demodulation circuit 41 and the diagram shown in FIG. Not control the integration of the integrator.

As described above, in the receiver of the spread spectrum communication system according to the fourth embodiment, before the data demodulation circuit 41 of FIG.
As shown in (a) and (b), since it is possible to obtain the pseudo baseband in-phase signal (I ₂ signal) and quadrature signal (Q ₂ signal) from the correlators 27 and 31, they are used as pilot signals. As a control, the controller 53 controls the filter time window of the filter in the data demodulation circuit 41 and the integration of the integrator.

As a result, the effect of PDI can be maximized and the error rate in multipathing can be improved.

Other effects are similar to those of the spread spectrum communication system according to the second embodiment.

(Fifth Embodiment) The transmitter and the receiver of the spread spectrum communication system according to the fifth embodiment are the same as the first embodiment.
Either the receiver or the transmitter of the spread spectrum communication system in any one of the first to fourth embodiments is used.

In mobile communication, the service area is divided into cells, and there are several mobile stations in each cell, and communication is performed with base stations installed in the respective cells.

FIG. 12 is a diagram showing a model when the service area is divided into cells, for explaining the spread spectrum communication system in the fifth embodiment of the present invention.

As shown in FIG. 12, base stations 55 to 67 are arranged in each cell, and mobile stations 69 to 79 are installed in the cell in which the base station 55 is arranged. It is considered that other cells have mobile stations in the same manner.

In this case, in the vicinity of the cell boundary, the required electric field strengths of the base station 55 and the adjacent base station 57 become substantially equal, causing interference. Therefore, in the conventional spread spectrum communication system, the same spreading code cannot be used between adjacent cells, and it is necessary to use different spreading codes. Therefore, as shown in FIG. 12, when there are six adjacent cells, a spreading code of 7 times (6 + 1) is required, and when there are few types of spreading codes, the spreading code alone is used to form cells. Was difficult. That is, assuming that each cell has six mobile stations, 7 × 6 = 42 codes are required.

However, in the spread spectrum communication system of the fifth embodiment of the present invention, the communication systems of the first to fourth embodiments are used as described above,
Separate cells using different spreading codes for each cell, 1
Within a cell, mobile stations can be distinguished by using the difference in delay amount. In this case, at least seven types of spread codes should be prepared.

As described above, in the spread spectrum communication system according to the fifth embodiment of the present invention, even if there are few kinds of codes, the division of the communication area can be easily realized. As a result, it is possible to easily construct a networked wireless communication system and realize a system with a high degree of freedom.

It is also possible to distinguish each cell by the amount of delay, and distinguish the mobile station in the same cell by the spreading code used. Also in this case, the same effect as that of the above-described embodiment is obtained.

Other effects are the same as those of the spread spectrum communication system in the first to fourth embodiments.

[0140]

As described above, in the spread spectrum communication system according to the first aspect of the present invention, the transmitting means includes the spread data spread by the spread code and the delay signal on the transmission side in which one of the spread codes is delayed. One of the spread data and the spread code that is not delayed is modulated into an in-phase signal and a quadrature signal, and these are multiplexed and transmitted, so that phase modulation is performed and the amplitude component becomes constant.

Further, the receiving means converts the transmission signal transmitted from the transmitting means into a baseband in-phase signal and a quadrature signal, performs correlation with a spread code, and then selects one of the in-phase correlation signal and the quadrature correlation signal. Data is demodulated by multiplying the delayed signal on the receiving side delayed by the one not involved in the delay by the transmitting means by the in-phase correlation signal and the quadrature signal which is involved in the delay by the transmitting means.

As a result, in the spread spectrum communication system according to claim 1 of the present invention, it is possible to use a non-linear circuit for the power amplifier and the like, while taking advantage of the advantage of the spread spectrum communication system using the conventional delaying and multiplexing system. Therefore, the cost can be reduced, the constraint on the dynamic range can be relaxed, and the delay and multiplexing method can be applied even in the case of large fading.

In the spread spectrum communication system according to claim 2, the transmitting means modulates the spread data and the spread code spread by the spread code into the in-phase signal and the quadrature signal, and one of the in-phase signal and the quadrature signal. Since the delayed signal on the transmission side, which is delayed, and the undelayed one of the in-phase signal and the quadrature signal are multiplexed and transmitted, phase modulation is performed and the amplitude component becomes constant.

Further, the receiving means converts the transmission signal transmitted from the transmitting means into a baseband in-phase signal and a quadrature signal, performs correlation with a spread code, and then selects one of the in-phase correlation signal and the quadrature correlation signal. Data is demodulated by multiplying the delayed signal on the receiving side delayed by the transmitting means that is not involved in the delay by the in-phase correlation signal and the quadrature correlation signal that is involved in the delay by the transmitting means.

As a result, the spread spectrum communication system of claim 2 has the same effect as the spread spectrum communication system of claim 1.

In the spread spectrum communication system according to the third aspect, the demodulating means can obtain the in-phase correlation signal or the quadrature correlation signal before integrating the multiplication signal.
The demodulating means in the receiving means uses the pilot signal as a pilot signal, and controls the predetermined time range of the filter for taking out the multiplication signal in the predetermined time range and the integration by the integrating means.

As a result, in the spread spectrum communication system according to the third aspect of the present invention, the effect of PDI can be maximized and the error rate under multipath can be improved.

In the spread spectrum communication system of claim 4, the transmitting means delays one of the spread data spread by the spread code and the delay signal on the transmission side delayed by one of the spread code and the spread data and the spread code. Since the in-phase signal and the quadrature signal are modulated into the in-phase signal and the signals are multiplexed and transmitted, phase modulation is performed and the amplitude component becomes constant.

Also, the receiving means correlates the first reception side delayed signal obtained by delaying the in-phase correlation signal obtained by correlating the in-phase signal of the pseudo baseband with the spread code and the orthogonal signal of the pseudo baseband with the spread code. First multiplied by the orthogonal correlation signal
Data is demodulated by adding the multiplication signal and the second multiplication signal obtained by multiplying the second reception-side delay signal obtained by delaying the orthogonal correlation signal and the in-phase correlation signal.

As a result, in the spread spectrum communication system according to claim 4 of the present invention, the amplitude of the addition signal obtained by adding the first multiplication signal and the second multiplication signal becomes constant, and the error rate is increased even though it is in an asynchronous state. Data can be demodulated without lowering.

Further, since the demodulation can be performed in an asynchronous state, the circuit scale is large, and the phase detector and the variable oscillator that require adjustment are unnecessary, and the circuit scale can be reduced.

Further, since the synchronization is not established, the time required for the synchronization becomes 0, and the throughput of burst data communication such as packet communication can be increased.

In the spread spectrum communication system of claim 5, the transmitting means modulates the spread data and the spread code spread by the spread code into an in-phase signal and a quadrature signal,
Since the transmission-side delay signal obtained by delaying one of the in-phase signal and the quadrature signal and the undelayed one of the in-phase signal and the quadrature signal are multiplexed and transmitted, phase modulation is performed and the amplitude component becomes constant. Become.

Further, the receiving means correlates the first delayed signal on the receiving side, which is a delay of the in-phase correlation signal obtained by correlating the in-phase signal of the pseudo baseband with the spread code, and the orthogonal signal of the pseudo baseband, with the spread code. First multiplied by the orthogonal correlation signal
Data is demodulated by adding the multiplication signal and the second multiplication signal obtained by multiplying the second reception-side delay signal obtained by delaying the orthogonal correlation signal and the in-phase correlation signal.

As a result, the same effect as that of the spread spectrum communication system according to claim 4 is obtained. In the spread spectrum communication system according to claim 6 of the present invention, the demodulation means can obtain the in-phase correlation signal and the quadrature correlation signal before the addition signal is integrated. A predetermined time range of the filter for extracting the addition signal in the time range and the integration by the integrating means are controlled.

As a result, in the spread spectrum communication system according to claim 6 of the present invention, the effect of PDI can be maximized and the error rate in multipathing can be improved.

In the spread spectrum communication system according to claim 7 of the present invention, the number of channels can be increased by combining the spread code and the delay time.

As a result, the spread spectrum communication system according to claim 7 of the present invention can have many users.

In the spread spectrum communication system according to claim 8 of the present invention, since the communication lines are distinguished by the difference in delay time in the same area and the difference in spreading code between different areas, there are few kinds of spreading codes. Even in this case, the division of the communication area can be easily realized.

As a result, in the spread spectrum communication system according to claim 8 of the present invention, it is possible to easily construct a networked wireless communication system and to realize a system with a high degree of freedom.

In the spread spectrum communication system according to claim 9 of the present invention, since the communication lines are distinguished by the difference of the spread codes in the same area and the difference of the delay time between the different areas, the kind of the spread code is different. Even if the number is small, division of the communication area can be easily realized.

As a result, the same effect as the spread spectrum communication system according to claim 8 is obtained.

[Brief description of drawings]

FIG. 1 is a schematic block diagram illustrating a transmitter of a general spread spectrum communication system using QPSK and direct spread.

FIG. 2 is a delay multiplexing method according to the first embodiment of the present invention, Q
FIG. 3 is a schematic block diagram illustrating a transmitter of a spread spectrum communication system using PSK and direct spread.

FIG. 3 is a schematic block diagram showing a receiver of a general spread spectrum communication system using QPSK and direct spread.

FIG. 4 is a delay multiplexing method according to the first embodiment of the present invention, Q
FIG. 3 is a schematic block diagram showing a receiver of a spread spectrum communication system using PSK and direct spread.

5 is a diagram showing waveforms of signals in a, b, c and d of FIG. 4 in the spread spectrum communication system according to the first example of the present invention.

FIG. 6 is a delay and multiplexing system according to a second embodiment of the present invention, Q
FIG. 3 is a schematic block diagram showing a receiver of a spread spectrum communication system using PSK and direct spread.

FIG. 7 is a diagram showing waveforms of signals in a, b, c, d, e, f, and g of FIG. 6 in the spread spectrum communication system according to the second example of the present invention.

FIG. 8 is a delay multiplexing method according to a third embodiment of the present invention, Q
FIG. 3 is a schematic block diagram showing a receiver of a spread spectrum communication system using PSK and direct spread.

9 is a diagram showing waveforms of output signals from the correlator and the multiplier shown in FIG. 8 when multipath occurs.

FIG. 10 is a delay / multiplex system according to a fourth embodiment of the present invention;
FIG. 3 is a schematic block diagram showing a receiver of a spread spectrum communication system using QPSK and direct spread.

FIG. 11 is a diagram showing waveforms of output signals from a correlator and an adder when multipath occurs.

FIG. 12 is a diagram showing a model when a service area is made into cells, for explaining a spread spectrum communication system according to a fifth example of the present invention.

FIG. 13 is a schematic block diagram showing a transmitter of a spread spectrum communication system using a conventional delay and multiplexing method, BPSK and direct spread.

FIG. 14 shows a spread spectrum communication system using a conventional delay / multiplex method, BPSK and direct spread.
It is a figure showing the waveform of the signal in a of 3, b, and c.

[Explanation of symbols]

 1 Data Generator 2 S / P Converter 3, 6, 25, 29, 40 Multiplier 5, 7 Modulator 9 Spreading Code Generator 10 Transmitter Delayer 11 Transmitter Local Signal Generator 13 Combiner 15 Transmitter Frequency conversion unit 17 Power amplifier 19 Transmission antenna 21 Reception antenna 22 Reception side frequency conversion unit 23 Distributor 27,31 Correlator 33,39,81 Delay element 35 Reception side local signal generator 37 Phase detector 38,41 Data demodulation circuit 43 I delay element 45 IQ multiplier 47 Q delay element 49 QI multiplier 51 Adder 53 Controller 55-67 Base station 69-79 Mobile station 83 Frequency converter 85 Local signal generator

Claims (9)

[Claims] 1. A spread spectrum communication system using direct spread, comprising: transmitting means and receiving means, wherein the transmitting means generates data and a predetermined spreading code is output to at least two outputs. Spreading code generating means for generating, spreading data for spreading the data with the spreading code output to one side of the spreading code generating means, and spreading data, and the other of the spreading data and the spreading code generating means. One of the spreading codes output to the other side, and delays one of the spreading code output to the other side of the spreading data and the spreading code generation means and the spreading data and the spreading code output to the other side of the spreading code generation means. With the one not
Quadrature phase modulation means for modulating the transmission side delay signal into an in-phase signal and a quadrature signal whose phases are quadrature, and a transmission signal for transmitting a transmission signal obtained by multiplexing the in-phase signal and the quadrature signal to the receiving means. Generating means, the receiving means distributing means for distributing the transmission signal into two signals, and converting means for converting the two distributed signals into a baseband in-phase signal and a quadrature signal, respectively. And an in-phase correlation unit that outputs an in-phase correlation signal obtained by correlating the baseband in-phase signal and the spread code, and an orthogonal correlation signal obtained by correlating the baseband quadrature signal and the spread code. Of the in-phase correlation signal and the quadrature correlation signal, whichever is not involved in the delay in the transmitting means is delayed by the same time as the delay time in the transmitting side, Receiving side delay means for generating a signal, of the in-phase correlation signal and the quadrature correlation signal, the one involved in the delay in the transmitting means, and the receiving side delay signal, multiplying means for generating a multiplication signal, A spread spectrum communication system, comprising: demodulation means for demodulating the data based on the multiplication signal. 2. A spread spectrum communication system using direct spread, comprising: transmitting means and receiving means, wherein the transmitting means generates data and a predetermined spreading code is output to at least two outputs. Spreading code generating means for generating, spreading data for spreading the data by the spreading code output to one side of the spreading code generating means, and generating spread data, and output to the other side of the spreading code generating means. A quadrature phase modulation unit that modulates the spread code and the spread data into an in-phase signal and a quadrature signal whose phases are quadrature, delays one of the in-phase signal and the quadrature signal, and generates a transmission-side delay signal. A transmitting-side delay unit that generates the transmitting-side delay signal, a transmitting signal that combines the transmitting-side delay signal, and the in-phase signal and the quadrature signal that are not delayed, to the receiving unit. Generating means, the receiving means distributes the transmission signal into two signals, and a converting means that converts the two distributed signals into a baseband in-phase signal and a quadrature signal, respectively. And an in-phase correlation unit that outputs an in-phase correlation signal obtained by correlating the baseband in-phase signal and the spread code, and an orthogonal correlation signal obtained by correlating the baseband quadrature signal and the spread code. A quadrature correlator that performs the same in-phase and quadrature correlator signals, which is not involved in the delay in the transmitter, is delayed by the same time as the delay time in the transmitter to generate a delay signal in the receiver. The side delay means, one of the in-phase correlation signal and the quadrature correlation signal that is involved in the delay in the transmission means, and the reception side delay signal are multiplied to generate a multiplication signal. A spread spectrum communication system including a multiplication means and a demodulation means for demodulating the data based on the multiplication signal. 3. The demodulating means includes a filter for extracting only a multiplication signal in a predetermined time range from the multiplication signals having a time spread, and integrating the extracted multiplication signal in the predetermined time range. 2. An integration means for demodulating the data, and a control means for controlling the filter and the integration means with the one of the in-phase correlation signal and the quadrature correlation signal that is not involved in the delay in the transmission means being a pilot signal. Or the spread spectrum communication system according to 2. 4. A spread spectrum communication system using direct spread, comprising: transmitting means and receiving means, wherein the transmitting means generates data and a predetermined spreading code is output to at least two outputs. Spreading code generating means for generating, spreading data for spreading the data with the spreading code output to one side of the spreading code generating means, and spreading data, and the other of the spreading data and the spreading code generating means. One of the spreading codes output to the other side, and delays one of the spreading code output to the other side of the spreading data and the spreading code generation means and the spreading data and the spreading code output to the other side of the spreading code generation means. With the one not
Quadrature phase modulation means for modulating the transmission side delay signal into an in-phase signal and a quadrature signal whose phases are quadrature, and a transmission signal for transmitting a transmission signal obtained by multiplexing the in-phase signal and the quadrature signal to the receiving means. Generating means, the receiving means distributing means for distributing the transmission signal into two signals, and converting means for converting the two distributed signals into a pseudo baseband in-phase signal and a quadrature signal, respectively. And an in-phase correlation unit that outputs an in-phase correlation signal obtained by correlating the in-phase signal of the pseudo baseband and the spreading code, and an orthogonal correlation that obtains the correlation of the orthogonal signal of the pseudo baseband and the spreading code. A quadrature correlation means for outputting a signal; a first reception side delay means for delaying the in-phase correlation signal by the same time as a delay time at the transmission side to generate a first reception side delay signal; Signal delayed by a time and same time of the delay, by multiplying a second reception-side delay means for generating a second reception-side delay signal, the first reception-side delay signal and the said orthogonal correlation signal,
A first multiplication means for generating a first multiplication signal, multiplying the second reception side delay signal and the in-phase correlation signal,
Second multiplication means for generating a second multiplication signal, addition means for adding the first multiplication signal and the second multiplication signal and outputting an addition signal, and demodulating the data based on the addition signal A spread spectrum communication system including demodulation means. 5. A spread spectrum communication system using direct spread, comprising: transmitting means and receiving means, wherein the transmitting means generates data and a predetermined spreading code is output to at least two outputs. Spreading code generating means for generating, spreading data for spreading the data by the spreading code output to one side of the spreading code generating means, and generating spread data, and output to the other side of the spreading code generating means. And a quadrature phase modulation means for modulating the spread code and the spread data into an in-phase signal and a quadrature signal having quadrature in phase, and delaying one of the in-phase signal and the quadrature signal to generate a transmission-side delay signal A transmission-side delay unit that generates a transmission signal that transmits to the reception unit a transmission signal that combines the transmission-side delay signal and the undelayed one of the in-phase signal and the quadrature signal The receiving means includes a distributing means for distributing the transmission signal into two signals, and a converting means for converting the two distributed signals into a pseudo baseband in-phase signal and a quadrature signal, respectively. An in-phase correlation means for outputting an in-phase correlation signal obtained by correlating the in-phase signal of the pseudo baseband and the spread code, and an orthogonal correlation signal obtained by correlation of the orthogonal signal of the pseudo baseband and the spread code And a first receiving-side delay means for delaying the in-phase correlation signal by the same time as the delay time at the transmitting side to generate a first receiving-side delay signal, and the orthogonal correlation signal A second receiving-side delay unit that delays by the same time as the delay time to generate a second receiving-side delay signal, and multiplies the first receiving-side delay signal and the orthogonal correlation signal,
A first multiplication means for generating a first multiplication signal, multiplying the second reception side delay signal and the in-phase correlation signal,
Second multiplication means for generating a second multiplication signal, addition means for adding the first multiplication signal and the second multiplication signal and outputting an addition signal, and demodulating the data based on the addition signal A spread spectrum communication system including demodulation means. 6. The demodulation means includes a filter for extracting only the addition signal in a predetermined time range from the addition signals having a temporal spread, and integrating the extracted addition signal in the predetermined time range. 6. The spread spectrum communication according to claim 4, further comprising: an integration unit that demodulates the data, and a control unit that controls the filter and the integration unit by using the in-phase correlation signal and the quadrature correlation signal as pilot signals. system. 7. The distinction between users is made by combining the spreading code and the delay time.
A spread spectrum communication system according to any one of 1. 8. A communication area is divided into a plurality of areas, a plurality of communication lines are distinguished by giving a difference in the delay time within the same area, and the spread codes are made different between different areas for communication. 7. The spread spectrum communication system according to claim 1, wherein lines are distinguished. 9. A communication area is divided into a plurality of areas, and in the same area, the spread codes are made different so as to distinguish communication lines, and a plurality of communication is made by making a difference in the delay time between different areas. 7. The spread spectrum communication system according to claim 1, wherein lines are distinguished.