JPH09270737A - Spread spectrum communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten initial. synchronization acquisition time when a receiver starts reception. SOLUTION: A transmitter 101 is provided with means (113-117 and 108) for generating the spread code synchronization pulses of a band narrower than the band of an information communication channel, adding them to the information communication channel and transmitting the spread code synchronization pulses. Also, the receiver 118 is provided with the means (128-131) for utilizing the synchronization pulses of the narrow band and limiting the phase search range of a spreading code used for the spreading of the information communication channel.

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 device used for digital radio communication such as a car phone and a mobile phone.

[0002]

2. Description of the Related Art FIG. 3 shows the configuration of a conventional spread spectrum communication device. In FIG. 3, 301 is a transmitter,
312 is a receiver. The transmitter 301 includes a frame assembling circuit 302, a multiplier 303, a band limiting filter 304,
DA conversion circuit 305, mixer 306, carrier wave oscillation circuit 3
07, power amplification circuit 308, transmission antenna 309, clock generation circuit 310, and spread code generation circuit 311. The receiver 312 includes a reception antenna 313, a low noise amplification circuit 314, a carrier wave oscillation circuit 315, and a mixer 3.
16, an AD conversion circuit 317, a reception filter 318, a multiplier 319, a frame decomposition circuit 320, a spread code phase search circuit 321, a spread code generation circuit 322, and a power detection circuit 323.

The operation of the spread spectrum communication device configured as described above will be described with reference to FIG.
First, in the transmitter 301, the transmission data is incorporated into a transmission frame format accompanied by various control information and the like in the frame assembling circuit 302, and then multiplied by a spreading code generated in the spreading code generating circuit 311. Bowl 303
And spread to a wideband signal. The spread signal is
Band-limited by the band-limiting filter 304, the DA converter 3
After being converted into an analog signal in 05, the mixer 306 modulates the carrier wave signal from the carrier wave oscillating circuit 307. This modulated signal is amplified by the power amplification circuit 309 and transmitted from the antenna 310. The spread code generation circuit 311 is driven by the clock supplied from the clock generation circuit 310.

On the other hand, in the receiver 312, the antenna 313
The signal received by the signal A is amplified by the low noise amplifier circuit 314, and then converted by the mixer 316 into a signal in the baseband band by the signal from the carrier wave oscillator circuit 315.
It is converted into a digital signal at 17. The waveform of this digital signal is shaped by the reception filter 318, multiplied by the spreading code from the spreading code generation circuit 322 and multiplied by the multiplier 319 to despread, and decomposed by the frame decomposing circuit 320 into received data and various control information. . In addition, the maximum value of the power of the despread received signal is detected by the power detection circuit 323, the phase of the spreading code is determined by the spreading code phase search circuit 321 based on the maximum value, and the phase of the spreading code is passed to the spreading code generation circuit 322. Be done.

[0005]

However, in the above-described conventional spread spectrum communication apparatus, the phase of the spread code generated by the spread code generation circuit of the receiver is set in the initial synchronization acquisition when the receiver starts reception. Since the operation to match the phase of the spreading code included in the received signal was performed using only the power information of the despread signal obtained by the power detection circuit, when the code length of the spreading code is long,
There was a problem that it took a long time to capture the initial synchronization.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an excellent spread spectrum communication device capable of performing initial synchronization in a short time.

[0007]

In order to solve the above problems, the present invention provides a transmitter, in a transmitter, which transmits a synchronization pulse having a narrower band than the band of the information communication channel, and a receiver. , The narrow-band synchronization pulse sent from the transmitter is used to limit the phase search range of the spreading code used for spreading the information communication channel, thereby shortening the initial synchronization acquisition time. is there. As a result, it is possible to obtain an excellent spread spectrum communication device capable of performing initial synchronization acquisition in a short time.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the invention described in claim 1 of the present invention, a transmitter is provided with transmitting means for transmitting, in addition to an information communication channel, a synchronization pulse having a narrower band than the band of the information communication channel, and the receiver is , Is provided with means for limiting the phase search range of the spreading code used for spreading the information communication channel by using the narrow band synchronization pulse, and has an effect of shortening the initial synchronization acquisition time. .

Further, the invention according to claim 2 is characterized in that the transmitter comprises means for transmitting a synchronization pulse having a narrower band than the band of the information communication channel on the same carrier as the communication channel.
Since the receiver is provided with a means for extracting a narrow band synchronization pulse from the received signal, it is possible to shorten the initial synchronization acquisition time without using a band other than the communication channel. Have. Further, it has the effect of simplifying the configuration of the circuit portion required in the transmitter and the receiver for shortening the synchronization acquisition time.

An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a configuration of a spread spectrum communication apparatus according to a first embodiment of the present invention. In FIG. 1, 101 is a transmitter and 118 is a receiver. The transmitter 101 includes the frame assembly circuit 10
2, multiplier 103, band limiting filter 104 (wide band), DA conversion circuit 105, mixer 106, carrier wave oscillation circuit 107, combining circuit 108, power amplification circuit 109, transmission antenna 110, clock generation circuit 111, spread code generation circuit 112. , Counter 113, band limiting filter (narrow band) 114, DA conversion circuit 115, mixer 11
6. The carrier wave oscillator circuit 117. The receiver 118 includes a receiving antenna 119 and a low noise amplifier circuit 12.
0, mixer 121, carrier wave oscillation circuit 122, AD conversion circuit 123, reception filter (wide band) 124, multiplier 12
5, spread code generation circuit 126, frame decomposition circuit 12
7, mixer 128, carrier wave oscillation circuit 129, AD conversion circuit 130, reception filter (narrow band) 131, spread code phase search circuit 132, and power detection circuit 133.

The operation of the spread spectrum communication apparatus configured as described above will be described with reference to FIG. First, in the transmitter 101, the transmission data is incorporated into a transmission frame format accompanied by various control information and the like in the frame assembling circuit 102, and then multiplied by a spreading code generated in a spreading code generating circuit 112 for multiplication. 10
3 and spread to a wideband signal. The spread signal is band-limited by the band-limiting filter 104, converted into an analog signal by the DA converter circuit 105, modulated by the mixer 106 by the carrier-band modulated signal from the carrier oscillator circuit 107, and amplified by the power amplifier circuit 109. And antenna 1
Sent from 10. The spread code generating circuit 112 and the counter 113 are driven by the clock supplied from the clock generating circuit 111. The counter 113 outputs a spread code start pulse at the start of the spread code cycle. The spread code head pulse output from the counter 113 is band-limited by the band limiting filter 114 having a narrower band than the spread data signal, converted into an analog signal by the DA conversion circuit 115, and spread by the mixer 116 from the carrier wave oscillation circuit 117. The signal is converted into a modulated signal in a carrier band different from the signal, added with the spread signal in the synthesis circuit 108, and then the power amplification circuit 109
Is amplified and transmitted.

In the receiver 118, first, the signal captured by the antenna 119 is amplified by a low noise amplifier and converted into signals of different basebands from the carrier wave oscillator circuits 122, 129 by the mixers 121, 128, respectively. After being converted into digital signals by the AD conversion circuits 123 and 130, respectively, the reception filters 1 of different bands are generated.
The waveform is shaped by 24 and 131, and a spread data signal and a spread code head pulse are obtained, respectively.

In the spreading code phase search circuit 132, the timing of the spreading code reset pulse for setting the state of the spreading code generation circuit 126 to the beginning of the cycle of the spreading code,
An operation is performed to match the timing of the received narrow band spreading code head pulse. At this point, the spread code generated by the spread code generation circuit 126 has a timing substantially matching the spread code of the received spread data signal.
Since the spread code head pulse is transmitted in a narrow band, it has a certain range of timing error. However, it is easy to make this error sufficiently shorter than the time of one cycle of the spreading code.

The spread code phase search circuit 132 searches only the range of the spread code timing error obtained by receiving the narrow band spread code head pulse. This is called a synchronization acquisition operation. This synchronization acquisition operation is a normal sliding correlation method. That is, the spread code generation circuit 1
26, the timing of the spread code generated is changed, and the spread code is added to the received spread data signal by the multiplier 125.
Is multiplied by to perform despreading, and a timing for maximizing the output of the power detection circuit 123 is searched for. After the synchronization acquisition operation is completed, the despread reception data signal is decomposed by the frame decomposition circuit 127 into reception data and various control information.

As described above, according to the first embodiment,
In addition to the information communication channel, the transmitter 101 is provided with means 113 to 117 and 108 for transmitting a sync pulse having a narrower band than the band of the information communication channel, and the receiver 118 is provided with the narrow band transmitted from the transmitter. By providing means 128 to 131 for limiting the phase search range of the spread code used for spreading the information communication channel by using the synchronization pulse, the range for performing the phase search of the spread code at the time of synchronization acquisition can be narrowed. This is possible, and an excellent effect that the synchronization acquisition time can be shortened is obtained.

(Second Embodiment) FIG. 2 shows the configuration of a spread spectrum communication apparatus according to a second embodiment of the present invention. In FIG. 2, 201 is a transmitter and 215 is a receiver. The transmitter 201 includes the frame assembly circuit 20.
2, multiplier 203, band limiting filter (wide band) 20
4, adder circuit 205, DA converter circuit 206, mixer 20
7, a carrier wave oscillation circuit 208, a power amplification circuit 209, a transmission antenna 210, a clock generation circuit 211, a spread code generation circuit 212, a counter 213, and a band limiting filter (narrow band) 214. The receiver 215 includes a reception antenna 216, a low noise amplification circuit 217, and a mixer 21.
8, carrier wave oscillation circuit 219, AD conversion circuit 220, reception filter (wide band) 221, multiplier 222, frame decomposition circuit 223, reception (narrow band) filter 224, spread code phase search circuit 225, spread code generation circuit 226, power It is composed of a detection circuit 227.

The operation of the spread spectrum communication apparatus configured as described above will be described with reference to FIG. First, in the transmitter 201, the transmission data is incorporated into a transmission frame format in which various control information and the like are attached by a frame assembling circuit 202, and then multiplied by a spread code generated by a spread code generating circuit 212. Bowl 2
03, spread to a wideband signal. The spread signal is band-limited by the band-limiting filter 204, converted into an analog signal by the DA conversion circuit 206, modulated by the mixer 207 by the carrier band modulation signal from the carrier oscillation circuit 208, and amplified by the power amplification circuit 209. And antenna 2
Sent from 10. The spread code generating circuit 212 and the counter 213 are driven by the clock supplied from the clock generating circuit 211. The counter 213 outputs a spread code head pulse at the head of the spread code cycle. The spread code head pulse output from the counter 213 is band-limited by the band limiting filter 214 having a band narrower than that of the spread signal, added by the wide band spread signal from the band limiting filter 204 by the adder circuit 205, and transmitted as a common carrier. To be done.

In the receiver 215, the signal first captured by the antenna 216 is the low noise amplifier 217.
Is amplified by the mixer 218, converted into a baseband signal by the signal from the carrier oscillation circuit 219 by the mixer 218, converted into a digital signal by the AD conversion circuit 220, and then spread data signals are extracted by the wideband reception filters 221. The narrow band reception filter 224 extracts the frequency component of the spread code head pulse to obtain the spread code head pulse.

In the spread code phase search circuit 225, the timing of the spread code reset pulse for setting the state of the spread code generation circuit 226 to the beginning of the cycle of the spread code,
An operation is performed to match the timing of the received narrow band spreading code head pulse. At this time, the spread code generated by the spread code generation circuit 226 has a timing substantially matching the spread code of the received spread data signal.
Since the spread code head pulse is transmitted in a narrow band, it has a certain range of timing error. However, it is easy to make this error sufficiently shorter than the time of one cycle of the spreading code.

The spread code phase search circuit 225 performs synchronization acquisition as in the case of the first embodiment. After the synchronization acquisition operation is completed, the despread reception data signal is decomposed by the frame decomposition circuit 223 into reception data and various control information. Here, the multiplier 222 that performs despreading has
Both the wideband spread data signal and the component of the narrowband spread code head pulse are input, but since the narrowband signal is attenuated in the process of despreading, the influence on the received data quality is a practical problem. It is possible to reduce it to a non-existent range.

As described above, according to the second embodiment,
The transmitter 201 is provided with means 213, 214, 205 for transmitting a sync pulse having a narrower band than the band of the information communication channel on the same carrier as the communication channel, and the receiver 215 is provided with
Means 224 for extracting a narrow band sync pulse from the received signal
By providing the above, it is possible to obtain an excellent effect that the acquisition time can be shortened while the frequency band used remains the same as that of the conventional spread spectrum communication device. Further, there is an effect that the number of components added to the transmitter and the receiver can be reduced.

[0023]

As described above, according to the present invention, in the transmitter, in addition to the information communication channel, the synchronization pulse having a narrower band than the band of the information communication channel is transmitted, and in the receiver,
By providing a function for limiting the phase search range of the spreading code used for spreading the information communication channel by utilizing the narrow band synchronization pulse, it is possible to reduce the initial synchronization acquisition time. can get.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a spread spectrum communication device according to a first embodiment of the present invention.

FIG. 2 is a schematic block diagram of a spread spectrum communication device according to a second embodiment of the present invention.

FIG. 3 is a schematic block diagram of a conventional spread spectrum communication device.

[Explanation of symbols]

 101 transmitter 102 frame assembly circuit 103 multiplier 104 band limiting filter 105 DA conversion circuit 106 mixer 107 carrier wave oscillating circuit 108 synthesis circuit 109 power amplification circuit 110 transmission antenna 111 clock generation circuit 112 spreading code generation circuit 113 counter 114 band limitation filter 115 DA converter circuit 116 Mixer 117 Carrier wave oscillator circuit 118 Receiver 119 Receive antenna 120 Low noise amplifier circuit 121 Mixer 122 Carrier wave oscillator circuit 123 AD converter circuit 124 Receive filter 125 Multiplier 126 Spread code generator circuit 127 Frame decomposition circuit 128 Mixer 129 Transmit wave Oscillation circuit 130 AD conversion circuit 131 Reception filter 132 Spread code phase search circuit 133 Power detection circuit 201 Transmitter 202 Frame assembly circuit 2 03 Multiplier 204 Band-limiting filter 205 Adder circuit 206 DA conversion circuit 207 Mixer 208 Carrier wave oscillation circuit 209 Power amplification circuit 210 Transmission antenna 211 Clock generation circuit 212 Spreading code generation circuit 213 Counter 214 Band-limiting filter 215 Receiver 216 Reception antenna 217 Low Noise amplification circuit 218 Mixer 219 Carrier wave oscillation circuit 220 AD conversion circuit 221 Reception filter 222 Multiplier 223 Frame decomposition circuit 224 Reception filter 225 Spread code phase search circuit 226 Spread code generation circuit 227 Power detection circuit 301 Transmitter 302 Frame assembly circuit 303 Multiply Unit 304 Band limiting filter 305 DA conversion circuit 306 Mixer 307 Carrier wave oscillation circuit 308 Power amplification circuit 309 Transmission antenna 310 Clock generation Circuit 311 Spread code generation circuit 312 Receiver 313 Reception antenna 314 Low noise amplification circuit 315 Carrier wave oscillation circuit 316 Mixer 317 AD conversion circuit 318 Reception filter 319 Multiplier 320 Frame decomposition circuit 321 Spread code phase search circuit 322 Spread code generation circuit 323 Power Detection circuit

Claims (2)

[Claims] 1. A transmitter comprises means for transmitting, in addition to an information communication channel, a sync pulse narrower than the band of the information communication channel, and a receiver utilizes the narrow band sync pulse to transmit information. A spread spectrum communication device having means for limiting a phase search range of a spread code used for spreading a communication channel. 2. The transmitter comprises means for transmitting a synchronization pulse in a narrower band than that of the information communication channel on the same carrier as that of the communication channel, and a receiver extracts the synchronization pulse in the narrow band from the received signal. Spread spectrum communication device having means for performing.