JPH08265244A - Base station device for spread spectrum communication - Google Patents

Abstract

PURPOSE: To reduce loss in a delay circuit, to vary a delay amount and to improve a path diversity effect by providing a frequency conversion means before and behind the delay circuit and operating the delay circuit in a low frequency band. CONSTITUTION: Between the duplexer 100 and antenna 102 of a base station 100, a mixer circuit 131, the delay circuit 133 operated in the low frequency band and the mixer circuit 132 are provided. Signals received by the antenna 102 are mixed with local oscillation signals and converted to the signals of the low frequency band in the mixer circuit 132, delayed by delay time τ in the delay circuit 133 and further, mixed with the local oscillation signals and returned to the signals of a high frequency band in the mixer circuit 131. In the meantime, the signals distributed from a spread spectrum transmitter 110 to the antenna 102 are similarly mixed with the local oscillation signals and converted to the signals of the low frequency band in the mixer circuit 131, delayed by the delay time τ in the delay circuit 133, further mixed with the local oscillation signals and returned to the signals of the high frequency band in the mixer circuit 132 and transmitted from the antenna 102.

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 base station device for transmitting / receiving a spread spectrum signal to / from a mobile station. In particular, the present invention relates to a base station device for spread spectrum communication provided with a delay circuit in order to enhance the path diversity effect.

[0002]

2. Description of the Related Art A spread spectrum communication system is a system in which signal energy is spread over a band much wider than the bandwidth of information for communication. Until now, it has been often used for space communication because of its small influence on other communication methods and its excellent distance measuring performance between transmitter and receiver. On the other hand, even in mobile radio communication where the number of users is rapidly increasing like mobile phones, spread spectrum communication methods are being considered with a focus on features such as multipath fading resistance and strong confidentiality. In mobile radio communication, all of the outdoor and indoor areas are assumed as a service area, so it is an issue to overcome the multipath fading peculiar to mobile radio and provide a high quality communication service.

FIG. 8 shows a first configuration example of a conventional spread spectrum communication system. Here, a configuration example of a base station and a mobile station that support a frequency division multiplexing (FDD) system in which the transmission frequency and the reception frequency are different from each other is shown. In the figure, the base station 100 has a plurality of (here, two) antennas 101 and 102, and the mobile station 200 has one antenna 201. The signal output from the spread spectrum transmitter 210 of the mobile station 200 is transmitted from the antenna 201 via the duplexer (transmission / reception duplexer) 202,
The antenna 101 of the base station 100 via the multipath propagation path,
102 is received. The signal received by the antenna 101 is input to the combining circuit 105 via the duplexer 103, and the signal received by the antenna 102 is delayed by the delay circuit 10.
It is delayed by the delay time τ at 6 and input to the combining circuit 105 via the duplexer 104. The signals combined by the combining circuit 105 are input to the spread spectrum receiver 120. Correlator 121 of spread spectrum receiver 120
Correlates the received signal to 1 of the spread code PN signal
A correlation signal for each chip length T (1 / spreading bandwidth) is output. The maximum peak detection circuit 122 selects the one with the highest level from the output signal of the correlator 121, and the demodulator 123 demodulates the selected signal.

Spread spectrum transmitter 1 of base station 100
The signal output from 10 is divided into two, and one of the signals is transmitted from the antenna 101 via the duplexer 103. The other signal is input to the delay circuit 106 via the duplexer 104, delayed by the delay time τ, and transmitted from the antenna 102. The signal transmitted from each antenna is received by the antenna 201 of the mobile station 200 via the multiple wave propagation path, and input to the spread spectrum receiver 220 via the duplexer 202. The correlator 221 of the spread spectrum receiver 220 performs correlation processing on the received signal, and the maximum peak detection circuit 222 selects the one with the highest level from the output signal of the correlator 221 and the demodulator 223.
Demodulates the selected signal.

FIG. 9 shows a second configuration example of a conventional spread spectrum communication system. Here, a configuration example of a base station and a mobile station corresponding to a time division multiplexing (TDD) system in which the transmission frequency and the reception frequency are the same and communication is performed alternately in time is shown. In the figure, a plurality of base stations 100 (here, 2
Mobile station 200 has one antenna 201. The signal output from the spread spectrum transmitter 210 of the mobile station 200 is transmitted from the antenna 201 via the transmission / reception changeover switch 203, and the antenna 10 of the base station 100 via the multiple wave propagation path.
1, 102 are received. The signal received by the antenna 101 is transmitted via the transmission / reception changeover switch 107 to the synthesizing circuit 10
The signal input to the antenna 5 and received by the antenna 102 is delayed by the delay time τ in the delay circuit 106, and input to the combining circuit 105 via the transmission / reception changeover switch 108. The signals combined by the combining circuit 105 are input to the spread spectrum receiver 120. The correlator 121 of the spread spectrum receiver 120 performs correlation processing on the received signal, the maximum peak detection circuit 122 selects the one with the highest level from the output signal of the correlator 121, and the demodulator 123 demodulates the selected signal. .

Spread spectrum transmitter 1 of base station 100
The signal output from 10 is divided into two, and one of the signals is transmitted from the antenna 101 via the transmission / reception changeover switch 107. The other signal is the transmission / reception changeover switch 10.
The signal is input to the delay circuit 106 via 8 and is transmitted from the antenna 102 after being delayed by the delay time τ. The signal transmitted from each antenna is transmitted to the mobile station 20 via the multipath propagation path.
0 is received by the antenna 201, and the transmission / reception changeover switch 2
It is input to the spread spectrum receiver 220 via 03. The correlator 221 of the spread spectrum receiver 220 performs correlation processing on the received signal, and the maximum peak detection circuit 222 selects the one with the highest level from the output signal of the correlator 221.
The demodulator 223 demodulates the selected signal.

The transmission / reception changeover switches 107, 108, 203 in the base station 100 and the mobile station 200 are switched by the switch control circuit (not shown) by the same transmission / reception timing signal as the TDD frame signal. The purpose of inserting the delay circuit 106 into the base station of the conventional spread spectrum communication system shown in FIG. 8 and FIG. 9 is to provide a plurality of independent paths separated by time τ as shown in FIG. The purpose is to increase the number of paths for selecting and increase the path diversity effect.

[0008]

In order to enhance the path diversity effect, the delay circuit 106 in the conventional spread spectrum communication system usually uses a delay element having a large delay amount such as SAW (surface acoustic wave element). Was there. However, since such a delay element has a large loss,
It was necessary to separately provide an amplifier for compensating for the loss. Further, since the delay circuit 106 is configured to operate in the high frequency band, it is difficult to arbitrarily change the delay amount.

It is an object of the present invention to provide a base station apparatus for spread spectrum communication which can reduce the loss in a delay circuit and can increase the path diversity effect by varying the delay amount.

[0010]

A base station device for spread spectrum communication according to the present invention is a delay circuit for setting a predetermined delay time difference between each signal transmitted from a plurality of antennas and each signal received by a plurality of antennas. The delay circuit is configured to operate in the low frequency band by including means for performing frequency conversion between the high frequency signal and the low frequency signal in the front and rear.

Further, in a spread spectrum communication base station apparatus for performing spread spectrum communication with a mobile station by a time division multiplexing (TDD) system, a delay circuit includes a band pass filter having a predetermined pass band and a band pass filter. An A / D conversion circuit for converting the output signal of the filter into a digital signal, a shift register for setting a predetermined delay amount for the digital signal, and a delay control circuit for controlling the delay amount,
D that converts the output signal of the shift register into an analog signal
A / A conversion circuit and transmission / reception switching in which the transmission signal or the reception signal is input to the bandpass filter according to the same transmission / reception timing signal as the frame signal, and the signal output from the D / A conversion circuit is extracted as the output signal of the delay circuit And a switch.

The delay amount set in the shift register of the delay circuit is controlled according to the spread of the delay time obtained from the correlation detection output of the spread spectrum receiver.

[0013]

The base station device for spread spectrum communication of the present invention can use a delay circuit which operates in a low frequency band because of the frequency conversion before and after the delay circuit. Further, by using the shift register as the delay circuit, the delay amount can be easily changed. further,
By controlling the delay amount according to the correlation detection output of the spread spectrum receiver, it becomes possible to perform adaptive control so as to increase the delay amount when the delay is small.

[0014]

【Example】

(First Embodiment) FIG. 1 shows the configuration (F) of the first embodiment of the present invention.
(Compatible with the DD system). In the figure, the base station 100
Is a plurality (here, two) of antennas 101, 102 and duplexers 103, 10 as in the conventional example shown in FIG.
4, combining circuit 105, spread spectrum transmitter 110,
It has a spread spectrum receiver 120. Mobile station 200
Is a single antenna 201, similar to the conventional example shown in FIG.
Duplexer 202, spread spectrum transmitter 21
0, having a spread spectrum receiver 220.

The feature of this embodiment is that a mixer circuit 131, a delay circuit 133 operating in a low frequency band, and a mixer circuit 132 are provided between the duplexer 104 of the base station 100 and the antenna 102. The mixer circuit 131,
A local oscillator signal of a predetermined frequency is input from the local oscillator 141 to 132. As a result, the signal received by the antenna 102 is mixed with the local oscillator signal by the mixer circuit 132 to be converted into a low frequency band signal, delayed by the delay circuit 133 by the delay time τ, and further transmitted by the mixer circuit 131 by the local oscillator. The signal is mixed with the signal and returned to a high frequency band signal, and is input to the combining circuit 105 via the duplexer 104. On the other hand, the signal distributed from the spread spectrum transmitter 110 to the antenna 102 is similarly mixed with the local oscillation signal by the mixer circuit 131 to be converted into a low frequency band signal, and delayed by the delay circuit 133 by the delay time τ, Further, the mixer circuit 132 mixes it with the local oscillation signal to return it to a high frequency band signal, and transmits it from the antenna 102.

FIG. 2 shows a configuration example of the high frequency circuit section of the first embodiment. In the figure, the transmission signal of frequency f ₃ output from the spread spectrum transmitter 210 of the mobile station 200 is input to the mixer circuit 242, and the local oscillator of the frequency (f ₀ + f ₁ −f ₃ ) output from the local oscillator 241 is transmitted. The signal is frequency mixed with the signal and becomes a signal of frequency (f ₀ + f ₁ ). This signal is transmitted from the antenna 201 via the duplexer 202.

The signal of the frequency (f ₀ + f ₁ ) received by the antenna 101 of the base station 100 is input to the mixer circuit 143 via the duplexer 103, and the local oscillator 141
The frequency is mixed with the local oscillation signal of frequency f ₀ output from the signal to be a signal of frequency f ₁ and input to the synthesis circuit 105.
The signal of the frequency (f ₀ + f ₁ ) received by the antenna 102 is input to the mixer circuit 132, is frequency-mixed with the local oscillation signal of the frequency f ₀ and becomes the signal of the frequency f ₁ , and the delay circuit 133
Is input to Signal delayed by a delay time τ in the delay circuit 133 is input to the mixer circuit 131, back to the signal of the frequency (f ₀ + f ₁₎ is the local oscillation signal and frequency mixing frequency f _0, the mixer circuit via the duplexer 104 The signal is input to 142, frequency-mixed with the local oscillation signal of frequency f ₀ to become a signal of frequency f ₁ , and is input to the synthesis circuit 105. The signals combined by the combining circuit 105 are input to the spread spectrum receiver 120.

Spread spectrum transmitter 1 of base station 100
The transmission signal of frequency f ₃ output from 10 is the mixer circuit 1
The frequency is mixed with the local oscillation signal of frequency f ₀ input to the local oscillator 44 and output from the local oscillator 141 to become a signal of frequency (f ₀ −f ₃ ), which is divided into two. One of the signals is transmitted from the antenna 101 via the duplexer 103.
The other signal is input to the mixer circuit 131 via the duplexer 104, is frequency-mixed with the local oscillation signal of the frequency f ₀ , becomes a signal of the frequency f ₃ , and is input to the delay circuit 133. The signal delayed by the delay time τ in the delay circuit 133 is input to the mixer circuit 132, frequency-mixed with the local oscillation signal of frequency f ₀ , and becomes a signal of frequency (f ₀ −f ₃ ) and transmitted from the antenna 102.

The signal of the frequency (f ₀ -f ₃ ) received by the antenna 201 of the mobile station 200 is input to the mixer circuit 243 via the duplexer 202, and the local oscillator 241.
The frequency is mixed with the local oscillation signal of the frequency (f ₀ + f ₁ −f ₃ ) output from the signal to be the signal of the frequency f ₁ and input to the spread spectrum receiver 220. With such a configuration, the delay circuit 133 of the base station 100 can be used in the low frequency band, and the circuit loss can be reduced as compared with the conventional high frequency band.

FIG. 3 shows a configuration example of the delay circuit 133 of the first embodiment. The delay circuit 133 processes a signal of frequency f ₃ during transmission and processes a signal of frequency f ₁ during reception.
In addition, the A / D conversion circuit that constitutes the delay circuit 133, the D / D conversion circuit
Since the A conversion circuit and the shift register are unidirectional, input / output reversibility is not established. Therefore, the delay circuit 13
In order to use 3 in two directions, two circuits are prepared for each of the above circuits, and in order to select each direction, the center frequency f ₁ ,
A band pass filter (BPF) of f ₃ is provided.

In the figure, during reception, the mixer circuit 13
At 2, a signal of frequency (f ₀ + f ₁ ) is converted into a signal of frequency f ₁ . The received signal is input to the A / D conversion circuit 305 via the bandpass filter 301 having the center frequency f ₁ and converted into a digital signal. This signal is input to the shift register 307, and the delay control circuit 320 sets a predetermined delay amount. The output signal of the shift register 307 is input to the D / A conversion circuit 309, converted into an analog signal, and output through the bandpass filter 302 having the center frequency f ₁ . The signal of this frequency f ₁ is the mixer circuit 1
It is input to 31 and converted into a signal of frequency (f ₀ + f ₁ ).

During transmission, the mixer circuit 131 converts a signal of frequency (f ₀ −f ₃ ) into a signal of frequency f ₃ . This transmission signal is input to the A / D conversion circuit 306 via the band pass filter 303 having the center frequency f ₃ and converted into a digital signal. This signal is input to the shift register 308, and the delay control circuit 320 sets a predetermined delay amount. The output signal of the shift register 308 is input to the D / A conversion circuit 310, converted into an analog signal, and output via the bandpass filter 304 having the center frequency f ₃ . This signal of frequency f ₃ is input to the mixer circuit 132 and converted into a signal of frequency (f ₀ −f ₃ ).

(Second Embodiment) FIG. 4 shows the configuration of the second embodiment of the present invention (corresponding to the TDD system). In the figure, the base station 100 includes a plurality of (two in this case) antennas 101 and 102, a combining circuit 105, as in the conventional example shown in FIG.
It has transmission / reception changeover switches 107, 108, a spread spectrum transmitter 110, and a spread spectrum receiver 120. The mobile station 200 has one antenna 201, a transmission / reception changeover switch 203, a spread spectrum transmitter 210, and a spread spectrum receiver 220 as in the conventional example shown in FIG.
Have.

The feature of this embodiment is that a mixer circuit 131, a delay circuit 134 operating in a low frequency band, and a mixer circuit 132 are provided between the transmission / reception changeover switch 108 of the base station 100 and the antenna 102. Mixer circuit 13
A local oscillator signal having a predetermined frequency is input from the local oscillator 141 to 1,132. As a result, the signal received by the antenna 102 is mixed with the local oscillator signal by the mixer circuit 132 to be converted into a low frequency band signal, delayed by the delay time τ by the delay circuit 134, and further transmitted by the mixer circuit 131 by the local oscillator. The signal is mixed with the signal and returned to a high frequency band signal, and is input to the combining circuit 105 via the transmission / reception changeover switch 108.
On the other hand, the spread spectrum transmitter 110 to the antenna 10
Similarly, the signal distributed to 2 is mixed with the local oscillation signal by the mixer circuit 131 to be converted into a low frequency band signal, delayed by the delay time τ by the delay circuit 134, and further mixed by the mixer circuit 1.
At 32, it is mixed with the local signal and returned to the high frequency band signal,
It is transmitted from the antenna 102.

FIG. 5 shows a first example of the high frequency circuit section of the second embodiment.
A configuration example of is shown. In the figure, the transmission signal of frequency f ₃ output from the spread spectrum transmitter 210 of the mobile station 200 is input to the mixer circuit 242 and mixed with the local oscillation signal of frequency f ₀ output from the local oscillator 241 to generate a frequency The signal becomes (f ₀ −f ₃ ). This signal is transmitted from the antenna 201 via the transmission / reception changeover switch 203.

The signal of the frequency (f ₀ -f ₃ ) received by the antenna 101 of the base station 100 is transmitted / received by the switch 10
7 is input to the mixer circuit 143, and the local oscillator 1
The frequency is mixed with the local oscillation signal of frequency f ₀ output from 41, and a signal of frequency f ₃ is input to the combining circuit 105. The signal of the frequency (f ₀ −f ₃ ) received by the antenna 102 is input to the mixer circuit 132, frequency-mixed with the local oscillation signal of the frequency f ₀ to become the signal of the frequency f ₃ , and the delay circuit 1
34 is input. Signal delayed by a delay time τ in the delay circuit 134 is input to the mixer circuit 131, back to the signal of the frequency (f ₀ -f ₃₎ are the local oscillation signal and frequency mixing frequency f _0, through the transceiver changeover switch 108 TE mixer circuit 1
The signal is input to 42, is frequency-mixed with the local oscillation signal of frequency f ₀ and becomes a signal of frequency f ₃ , and is input to the synthesis circuit 105. The signals combined by the combining circuit 105 are input to the spread spectrum receiver 120.

Spread spectrum transmitter 1 of base station 100
The transmission signal of frequency f ₃ output from 10 is the mixer circuit 1
The frequency is mixed with the local oscillation signal of frequency f ₀ input to the local oscillator 44 and output from the local oscillator 141 to become a signal of frequency (f ₀ −f ₃ ), which is divided into two. One of the signals is transmitted from the antenna 101 via the transmission / reception changeover switch 107. The other signal is input to the mixer circuit 131 via the transmission / reception changeover switch 108, frequency-mixed with the local oscillation signal of frequency f ₀ to become a signal of frequency f ₃ , and the delay circuit 134
Is input to The signal delayed by the delay time τ in the delay circuit 134 is input to the mixer circuit 132, frequency-mixed with the local oscillation signal of frequency f ₀ , and becomes a signal of frequency (f ₀ −f ₃ ) and transmitted from the antenna 102.

The signal of the frequency (f ₀ -f ₃ ) received by the antenna 201 of the mobile station 200 is transmitted / received by the transmission / reception changeover switch 20.
3 is input to the mixer circuit 243, and the local oscillator 2
41 is mixed with the local oscillation signal of frequency f ₀ output from 41 to form a signal of frequency f ₃ , and the spread spectrum receiver 2
It is input to 20. Switch control circuit 1 of base station 100
Reference numeral 51 switches transmission / reception changeover switches 107 and 108 in conjunction with each other in accordance with the same transmission / reception timing signal as the TDD frame signal given from the spread spectrum receiver 120. Switch control circuit 251 of mobile station 200
Is the TD provided by the spread spectrum receiver 220.
The transmission / reception changeover switch 203 is switched according to the same transmission / reception timing signal as the D frame signal.

With such a configuration, the delay circuit 134 of the base station 100 can be used in the low frequency band, and the circuit loss can be reduced as compared with the conventional high frequency band. FIG. 6 shows a second configuration example of the high frequency circuit section of the second embodiment. In the figure, the configuration of the mobile station 200 is the same as that of the first configuration example shown in FIG.

The signal of the frequency (f ₀ −f ₃ ) received by the antenna 101 of the base station 100 is input to the mixer circuit 145 and mixed with the local oscillation signal of the frequency f ₀ output from the local oscillator 141. Becomes a signal of frequency f ₃ and is input to the synthesizing circuit 105 via the transmission / reception changeover switch 161. The signal of the frequency (f ₀ −f ₃ ) received by the antenna 102 is input to the mixer circuit 132, frequency-mixed with the local oscillation signal of the frequency f ₀ to become the signal of the frequency f ₃ , and the delay circuit 1
34 is input. The signal delayed by the delay time τ in the delay circuit 134 is input to the combining circuit 105 via the transmission / reception changeover switch 162. The signals combined by the combining circuit 105 are input to the spread spectrum receiver 120.

Spread spectrum transmitter 1 of base station 100
The transmission signal of frequency f ₃ output from 10 is input to the mixer circuit 145 via the transmission / reception changeover switch 161.
The frequency is mixed with the local oscillation signal of the frequency f ₀ output from the local oscillator 141 and becomes a signal of the frequency (f ₀ −f ₃ ) and is divided into two. One of the signals is transmitted from the antenna 101. The other signal is input to the mixer circuit 146, and the frequency
The frequency is mixed with the local oscillation signal of f ₀ to become a signal of frequency f ₃ , and the delay circuit 134 is transmitted via the transmission / reception changeover switch 162.
Is input to The signal delayed by the delay time τ in the delay circuit 134 is input to the mixer circuit 132, frequency-mixed with the local oscillation signal of frequency f ₀ , and becomes a signal of frequency (f ₀ −f ₃ ) and transmitted from the antenna 102.

By adopting such a configuration, the delay circuit 134 of the base station 100 can be used in the low frequency band, and the circuit loss can be reduced as compared with the conventional high frequency band. Further, the transmission / reception changeover switches 161 and 162 may be of a low frequency band, and the transmission / reception changeover switch 10 of the high frequency band shown in FIG.
It is possible to reduce the circuit loss as compared with Nos. 7 and 108.

FIG. 7 shows a configuration example of the delay circuit 134 of the second embodiment. The delay circuit 134 processes the signal of the frequency f ₃ during transmission and reception. Further, since the A / D conversion circuit, the D / A conversion circuit, and the shift register which form the delay circuit 134 are unidirectional, reversibility of input / output is not established. Therefore, in order to use the delay circuit 134 bidirectionally, a transmission / reception changeover switch that is switched by the switch control circuit 151 is used.

In the figure, during reception, the mixer circuit 13
At 2, the signal of frequency (f ₀ −f ₃ ) is converted to the signal of frequency f ₁ . This reception signal is input from the contact point d of the transmission / reception changeover switch 332 to the band pass filter 303 of the center frequency f ₃ via the contact point a of the transmission / reception changeover switch 331. The output signal of the bandpass filter 303 is the A / D conversion circuit 30.
It is input to 6 and converted into a digital signal. This signal is input to the shift register 308, and the delay control circuit 32
A value of 0 sets a predetermined delay amount. Shift register 3
The output signal of 08 is input to the D / A conversion circuit 310, converted into an analog signal, and output through the bandpass filter 304 having the center frequency f ₃ . The signal of the frequency f ₃ is input from the contact point f of the transmission / reception changeover switch 332 to the mixer circuit 131 via the contact point c of the transmission / reception changeover switch 331, and is converted into a signal of the frequency (f ₀ −f ₃ ).

At the time of transmission, the mixer circuit 131 converts a signal of frequency (f ₀ −f ₃ ) into a signal of frequency f ₃ . This transmission signal is input to the bandpass filter 303 having the center frequency f ₃ via the contact b of the transmission / reception changeover switch 331. Similarly, the output signal of the bandpass filter 303 is A /
It is output via the D conversion circuit 306, the shift register 308, the D / A conversion circuit 310, and the band pass filter 304 having the center frequency f ₃ . The signal of the frequency f ₃ is input to the mixer circuit 132 via the contact e of the transmission / reception changeover switch 332 and converted into a signal of the frequency (f ₀ −f ₃ ).

Since signals of the same frequency are transmitted and received in the TDD method, the reversibility of the propagation path is used to adaptively adjust the delay amount given to the shift register 308 by using the correlation detection output of the spread spectrum receiver 120. It is possible to control. That is, the spread spectrum receiver 120
The correlation detection output of the correlator 121 is input to the delay control circuit 320, and the delay amount is adaptively controlled so that the delay amount is set large when the delay is small.

[0037]

As described above, since the base station apparatus for spread spectrum communication of the present invention performs the delay processing for enhancing the path diversity effect by converting from the high frequency band to the low frequency band, the conventional SAW The circuit loss can be reduced as compared with the device. Furthermore, since the delay circuit can be configured by a digital circuit, the size can be reduced. Moreover, since the delay amount can be easily changed by the shift register, the delay amount corresponding to various propagation situations can be adaptively set.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration (corresponding to an FDD system) of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of a high frequency circuit unit of the first embodiment.

FIG. 3 is a block diagram showing a configuration example of a delay circuit 133 according to the first embodiment.

FIG. 4 is a block diagram showing the configuration (corresponding to the TDD system) of the second embodiment of the present invention.

FIG. 5 is a block diagram showing a first configuration example of a high frequency circuit section according to a second embodiment.

FIG. 6 is a block diagram showing a second configuration example of the high-frequency circuit unit according to the second embodiment.

FIG. 7 is a block diagram showing a configuration example of a delay circuit 134 according to a second embodiment.

FIG. 8 is a block diagram showing a first configuration example (corresponding to the FDD system) of a conventional spread spectrum communication system.

FIG. 9 is a block diagram showing a second configuration example (corresponding to the TDD system) of a conventional spread spectrum communication system.

FIG. 10 is a diagram for explaining the operation of path diversity.

[Explanation of symbols]

100 base station 101, 102 antenna 103, 104 duplexer 105 combining circuit 106 delay circuit (for high frequency) 107, 108 transmission / reception changeover switch (for high frequency) 110 spread spectrum transmitter 120 spread spectrum receiver 121 correlator 122 maximum peak detection circuit 123 Demodulators 131, 132, 142, 143, 144, 145, 1
46 Mixer circuit 133,134 Delay circuit (for low frequency) 141 Local oscillator 151 Switch control circuit 161,162 Transmission / reception selector switch (for low frequency) 200 Mobile station 201 Antenna 202 Duplexer 203 Transmission / reception selector switch 210 Spread spectrum transmitter 220 Spread spectrum Receiver 221 Correlator 222 Maximum peak detection circuit 223 Demodulator 241 Local oscillator 242, 243 Mixer circuit 251 Switch control circuit 301, 302, 303, 304 Band pass filter (BPF) 305, 306 A / D conversion circuit 307, 308 Shift Register 309,310 D / A conversion circuit 320 Delay control circuit 331,332 Transmission / reception changeover switch

Claims (3)

[Claims] 1. A plurality of antennas for transmitting and receiving a spread spectrum signal, a spread spectrum transmitter for outputting a spread spectrum signal of transmission data using a predetermined spread code, and a spread spectrum signal for the spread code. A spread spectrum receiver that despreads the spectrum to output received data, means for distributing the signal output from the spread spectrum transmitter to the plurality of antennas, and a signal received by the plurality of antennas. Spread spectrum including means for combining and inputting to the spread spectrum receiver, and a delay circuit that sets a predetermined delay time difference between each signal transmitted from the plurality of antennas and each signal received by the plurality of antennas In the base station for communication, a high frequency signal and a low frequency signal are provided before and after the delay circuit. 2. A base station apparatus for spread spectrum communication, comprising: means for performing frequency conversion, and wherein the delay circuit operates in a low frequency band. 2. The spread spectrum communication base station apparatus according to claim 1, wherein spread spectrum communication is performed with a mobile station by a time division multiplexing (TDD) system. The delay circuit has a band having a predetermined pass band. A pass filter, an A / D conversion circuit for converting the output signal of the band pass filter into a digital signal, a shift register for setting a predetermined delay amount for the digital signal, a delay control circuit for controlling the delay amount, and a shift A D / A conversion circuit for converting the output signal of the register into an analog signal, and a transmission signal or a reception signal according to the same transmission / reception timing signal as the frame signal is input to the band pass filter and output from the D / A conversion circuit. Base for spread spectrum communication, comprising: a transmission / reception changeover switch for extracting the generated signal as an output signal of the delay circuit Station equipment. 3. The spread spectrum communication base station apparatus according to claim 2, wherein the delay amount set in the shift register of the delay circuit is set in accordance with the spread of the delay time obtained from the correlation detection output of the spread spectrum receiver. A base station device for spread spectrum communication, characterized in that it is configured to control.