JP2000124874A - Device and method for relay transmission for spread spectrum communication and recording medium with control program recorded therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide spread spectrum communication relay transmission equipment, capable of relay transmission while effectively utilizing frequencies without lowering the reception quality. SOLUTION: A spreading code sequence control part 15 of a repeater 1 discriminates the spreading code of a received signal, based on a correlative value outputted by a correlator 13 and outputs a spreading code sequence A and a spreading code sequence B, having mutual correlative characteristics orthogonal to the spreading code sequence A or having nearly the same characteristics. A spreader 16 spreads a regenerative signal through the spreading code sequence B outputted from the spreading code sequence control part 15. The regenerative signal spread by the spreader 16 is transmitted through a modulating part 17, transmitting part 18 and transmitting antenna 19 to a receiver 2. A spread code sequence control part 25 of the receiver 2 discriminates the spread code of the received signal, based on a correlative value outputted by a correlator 23 and outputs the spreading code sequence B.

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 relay transmission apparatus, a relay transmission method thereof, and a recording medium storing a control program thereof, and more particularly to a relay transmission system in a communication system using a geostationary satellite.

[0002]

2. Description of the Related Art Broadcasting using geosynchronous satellites has become popular at present, and with the progress of digitalization of communication devices,
In the future, the use of mobile communication devices is expected to expand further.

Conventionally, in a communication system using a geostationary satellite, there are places where transmission signals from the geostationary satellite are shielded by mountains, buildings, and the like, and cannot be received. Particularly in urban areas, there is a problem of shielding by buildings.

As a method of stably receiving a transmission signal from a geostationary satellite in such a place, there is a method of performing regenerative relay transmission as shown in FIG. In this case, a transmission signal from the base station 51 is transmitted to the receiver 54 via the communication satellite 52, but the transmission signal is shielded by the building A or the like.

Therefore, the antenna of the repeater 53 is installed on the building B which is not affected by the shielding by the building A, and the transmission signal from the communication satellite 52 is transmitted via the repeater 53 to the receiver 5.
4

When the transmission signal from the communication satellite 52 is received by the relay device 53, the power of the modulated wave of the reproduced signal is simply amplified and relayed to the receiver 54, or the frequency is converted before being transmitted to the receiver 54. Sending.

[0007]

In the above-mentioned conventional relay transmission system in a communication system using a geostationary satellite,
If the relay device simply amplifies the power of the modulated wave of the reproduced signal and relays the signal, the receiver will not only receive the signal received from the relay device, but also receive the signal reflected by the building from the transmission signal of the communication satellite. However, the reception quality at the receiver deteriorates due to the influence of the multipath fading.

[0008] Further, when performing transmission after performing frequency conversion in the relay apparatus, the above-mentioned effect of multipath fading is eliminated, but a new frequency band is consumed for relaying, so from the viewpoint of effective use of frequency resources. There's a problem.
In particular, when the communication method is spread spectrum communication, there is a problem because the transmission speed of information and the frequency bandwidth after spread are generally in a proportional relationship.

As means for solving these problems, Japanese Patent Laid-Open Publication No.
In the technique disclosed in Japanese Patent No. 36794, it is proposed that data be framed and transmitted by time division. However, control for time division transmission is required, and continuous transmission is performed as in satellite broadcasting. Cannot be applied when

Accordingly, an object of the present invention is to solve the above-mentioned problems, to provide a spread spectrum communication relay transmission apparatus and a relay transmission method capable of relay transmission without deteriorating reception quality and effectively using frequency, and a relay transmission method thereof. An object of the present invention is to provide a recording medium on which the control program is recorded.

[0011]

SUMMARY OF THE INVENTION A spread spectrum communication relay transmission apparatus according to the present invention is a spread spectrum communication relay transmission apparatus for regenerating and relaying a transmission signal from a transmission source to a receiver, and regenerating and relaying the transmission signal. In this case, the transmission is performed after spreading using a spreading code sequence different from that at the time of reception.

Another spread-spectrum communication relay transmission apparatus according to the present invention is a spread-spectrum communication relay transmission apparatus that reproduces and relays a transmission signal from a transmission source to a receiver, and includes a spread code sequence of the transmission signal from the transmission source. And a transmitting unit that spreads the transmission signal using a spreading code sequence different from the spreading code sequence determined by the determining unit and then transmits the spread signal.

[0013] A spread spectrum communication relay transmission method according to the present invention is a spread spectrum communication relay transmission method for regenerating and relaying a transmission signal from a transmission source to a receiver. Transmission is performed after spreading using a spreading code sequence.

Another spread-spectrum communication relay transmission method according to the present invention is a spread-spectrum communication relay transmission method for regenerating and relaying a transmission signal from a transmission source to a receiver, wherein a spread code sequence of the transmission signal from the transmission source is provided. And transmitting the transmission signal after spreading the transmission signal using a spreading code sequence different from the determined spreading code sequence.

A recording medium storing a spread spectrum code sequence control program according to the present invention is a recording medium storing a spread spectrum code sequence control program for causing a spread code sequence control unit to select a spread code sequence. The spread-spectrum code sequence control program causes the spread-code sequence control unit to transmit the transmission signal after regenerating and relaying the transmission signal using a spread code sequence different from that at the time of reception.

A recording medium storing another spread spectrum code sequence control program according to the present invention is a recording medium storing a spread spectrum code sequence control program for causing a spread code sequence control section to select a spread code sequence. The spread spectrum code sequence control program causes the spread code sequence control unit to determine a spread code sequence of a transmission signal from the transmission source, and sets the transmission signal to a spread code sequence different from the determined spread code sequence. After being used and spread, it is transmitted.

That is, the spread-spectrum communication relay transmission apparatus of the present invention is a device that, when a shield such as a building is present in a propagation path in communication using a spread-spectrum system, bypasses the shield and relays the same. is there.

More specifically, in the spread spectrum communication relay transmission apparatus of the present invention, when the receiver cannot directly receive the transmission signal of the communication satellite due to a shield or the like, the transmission signal of the communication satellite is regenerated and relayed by the relay apparatus. Thus, reception at the receiver becomes possible.

In the case of regenerating and relaying in a relay device, a signal received by the relay device is spread using a spreading code sequence different from that at the time of reception, and then transmitted, so that a frequency band to be used is not expanded and multipath fading is performed. Relay transmission excluding the effects of

[0020]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a spread spectrum communication relay transmission apparatus according to one embodiment of the present invention. In the figure, a relay device 1 includes a receiving antenna 11, a receiving unit 12, a correlator 13, a demodulating unit 14,
Spreading code sequence control section 15, spreader 16, modulation section 17
, Transmission unit 18, transmission antenna 19, control memory 2
0.

The receiver 2 includes a receiving antenna 21 and a receiving unit 2
2, a correlator 23, a demodulation unit 24, a spreading code sequence control unit 25, and a control memory 26. The spreading code sequence control unit 15 of the relay device 1 and the receiver 2
25 operates by executing a program stored in the control memories 20 and 26, and the control memories 20 and 26
(Read only memory), IC (integrated circuit) memory, and the like can be used.

The receiving unit 12 of the relay device 1
1 is subjected to quasi-synchronous detection and converted into a baseband signal. The correlator 13 correlates the output of the receiving unit 12 with the spread code sequence A, and outputs a received signal synchronized with the spread code. The demodulation unit 14 synchronizes the carrier of the received signal and the clock, and outputs a reproduced signal.

The spread code sequence control unit 15 determines the spread code of the received signal based on the correlation value output from the correlator 13 and determines the spread code sequence A and the characteristics that the cross code characteristics of the spread code sequence A are orthogonal or similar. And outputs the spreading code sequence B. Here, as the spreading code sequence B having a cross-correlation characteristic similar to that of orthogonal, a PN (Pseudo No.) composed of linear feedback shift registers having different feedback tap positions.
is) sign.

The spreader 16 spreads the reproduced signal with the spread code sequence B output from the spread code sequence control unit 15. The reproduced signal spread by the spreader 16 is transmitted to the receiver 2 via the modulation unit 17, the transmission unit 18, and the transmission antenna 19.

The receiving section 22 of the receiver 2 has a receiving antenna 21
Is converted into a signal in the baseband. The correlator 23 outputs a correlation value between the output of the receiving unit 22 and the spread code sequence B, and outputs a received signal synchronized with the spread code.

The demodulation unit 24 synchronizes carrier and clock of the received signal and demodulates the received data. The spread code sequence control unit 25 determines the spread code of the received signal based on the correlation value output from the correlator 23, and outputs a spread code sequence B.

It should be noted that the relay device 1 and the receiver 2 having the above configuration
As shown in FIG. 6, a transmission signal from a base station 51 is relayed by a communication satellite 52 and a relay device 53
Is used in a communication system that is received by the receiver 54 after being relayed.

FIG. 2 is a block diagram showing a configuration of the spread code sequence control unit 15 of the relay apparatus 1 of FIG. In the figure,
The spreading code sequence control unit 15 includes a peak value detector 31, a spreading code sequence selection unit 32, and switches 33 and 34.

The peak value detector 31 of the spreading code sequence controller 15 detects the peak value of the output of the correlator 13. Switches 33 and 34 are respectively provided with spreading code sequences A1 to An and B1 to B
n is switched. The spreading code sequence selection unit 32 determines the spreading code sequence A of the received signal based on the peak value detected by the peak detector 31, selects the spreading code sequence B to be used for the spreader 16, and further determines the determination results and The switches 33 and 34 are set based on the selection result.

FIG. 3 is a block diagram showing a configuration of the spread code sequence control unit 25 of the receiver 2 of FIG. In the figure, the spreading code sequence control unit 25 includes a peak value detector 41, a spreading code sequence selection unit 42, and a switch 43.

The peak value detector 41 of the spreading code sequence control unit 25 detects the peak value of the output of the correlator 23. The switch 43 switches the spreading code sequences B1 to Bn. The spreading code sequence selection unit 42 determines the spreading code sequence B of the received signal based on the peak value detected by the peak detector 41, and sets the switch 43 based on the determination result.

FIG. 4 is a flowchart showing the processing operation of the spreading code sequence control unit 15 of the relay apparatus 1 of FIG.
5 is a flowchart showing a processing operation of the spreading code sequence control unit 25 of the receiver 2 in FIG. The processing operation of the communication system according to the embodiment of the present invention will be described with reference to FIGS. Note that the processing operations shown in FIGS. 4 and 5 are realized by executing the programs stored in the control memories 20 and 26 by the spreading code sequence control units 15 and 25.

The transmission signal from the communication satellite 52 is received by the reception antenna 11 of the relay device 1, is quasi-synchronously detected by the reception unit 12, and is converted into a baseband signal. In the correlator 13, a baseband signal output from the receiving unit 12,
The correlation with the spreading code sequence A is obtained, the spreading code is synchronized (despreading), and a correlation value is output.

At the time of initialization, the spreading code sequence control unit 15 outputs a plurality of spreading code sequences A1 to An predetermined in the spreading code sequence selection unit 31 to the correlator 13 while switching them by the switch 33 (step S1 in FIG. 4). , S
2).

The spread code sequence selector 32 determines the spread code used in the received signal based on the peak value of the correlation value output of the correlator 13 detected by the peak value detector 31 (step S3 in FIG. 4). , S4), and sets a spreading code sequence A to be output to the correlator 13 based on the determination result.

The demodulation unit 14 reproduces a received signal by performing carrier synchronization and phase synchronization. The spreading code sequence control unit 15 determines a plurality of predetermined spreading code sequences B1 to B1.
From Bn, a spreading code sequence B having a cross-correlation characteristic that is orthogonal or nearly orthogonal to the spreading code sequence A used for the correlator 13 is selected and output to the spreader 16 (step S in FIG. 4).
5).

The reproduced signal is spread in the spreader 16 by the spread code sequence B selected by the spread code sequence control unit 15. The output of the spreader 16 is modulated by the modulator 17,
The signal is converted to a desired frequency and output level by the transmission unit 18, amplified, and transmitted to the receiver 2 via the transmission antenna 19.

The transmission signal of the relay device 1 is received by the reception antenna 21 of the receiver 2, is subjected to quasi-synchronous detection by the reception unit 22, and is converted into a baseband signal. The correlator 23 obtains a correlation between the baseband signal output from the receiving unit 22 and the spreading code sequence B, synchronizes the spreading code, and outputs a correlation value.

At the time of initialization, the spreading code sequence control unit 25 outputs a plurality of spreading code sequences B1 to Bn predetermined in the spreading code sequence selection unit 41 to the correlator 23 while switching them by the switch 43 (step S11 in FIG. 5). , S1
2).

The spread code sequence selector 42 determines the spread code used for the received signal based on the peak value of the correlation value output of the correlator 23 detected by the peak value detector 41 (step S13 in FIG. 5). , S14), and sets a spreading code sequence B to be output to the correlator 23 based on the determination result. The demodulation unit 24 performs carrier synchronization and phase synchronization,
Outputs received data.

Although the above embodiment has been described with reference to a single relay apparatus, spreading code sequences A1 to A1 having orthogonal correlation or orthogonal cross-correlation characteristics held by the relay apparatus and the receiving station are used.
By increasing the number of n, B1 to Bn, the number of relays can be easily increased.

Further, in the above-described embodiment, the case where the terminal station performs only the reception is shown, but it is possible to extend the case where the terminal station performs the transmission. Further, in the above embodiment, the communication satellite 5
Although the method of relaying the transmission signal of No. 2 has been described, the communication satellite 52 can be expanded to other than satellite communication by replacing the communication satellite 52 with another transmission means.

Furthermore, in the above embodiment, at the time of initial setting, the spread code sequence control units 15 and 25 send the correlator 1
3, 23, the spreading code sequences A1 to An, B1 to Bn
Are sequentially switched, and the spreading code sequences A1 to An and B1 to Bn used for the received signal are determined. However, all the spreading code sequences A1 to An and B1 to B1 to B2 to be used are determined.
It is also possible to arrange the correlators suitable for each of n in parallel to synchronize the spread codes, and to always determine the spread code sequence used for the transmission signal. In this case, the peak value detector 31,
The number of input signals to 41 is the number of parallel correlators.

As described above, the spreading code sequences A1 to An used for the transmission signal of the communication satellite 52 and the spreading code sequences B1 to B used for the transmission signal from the relay device 1 to the receiver 2 are used.
By setting n and a code having a cross-correlation characteristic that is orthogonal or similar to orthogonal, the receiver 2 can receive the signal without being affected by reflected waves / diffraction waves of a communication satellite in which multipath distortion has occurred. At this time, since a frequency band is not newly consumed for relaying, effective use of frequency resources can be achieved.

In this case, even when there is an obstacle that blocks the propagation path and the transmission signal of the communication satellite 52 cannot be directly received by the receiver 2, the relay device 1 is used as in the conventional example. Therefore, the signal can be received by the receiver 2.

[0046]

As described above, according to the present invention, in a spread spectrum communication relay transmission apparatus for regenerating and relaying a transmission signal from a transmission source to a receiver, when a transmission signal is regenerated and relayed, the spread signal differs from that at the time of reception. By transmitting after spreading using a code sequence, there is an effect that relay transmission can be performed without deteriorating reception quality and effectively using frequency.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a spread spectrum communication relay transmission apparatus according to one embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a spreading code sequence control unit of the relay device of FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of a spreading code sequence control unit of the receiver in FIG. 1;

FIG. 4 is a flowchart illustrating a processing operation of a spreading code sequence control unit of the relay device of FIG. 1;

FIG. 5 is a flowchart showing a processing operation of a spreading code sequence control unit of the receiver in FIG. 1;

FIG. 6 is a diagram showing a configuration of a communication system using a communication satellite.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Repeater 2 Receiver 11 and 21 Receiving antenna 12 and 22 Receiving unit 13 and 23 Correlator 14 and 24 Demodulating unit 15 and 25 Spreading code sequence control unit 16 Spreader 17 Modulating unit 18 Transmitting unit 19 Transmitting antenna 20 and 26 Control Memory 31, 41 Peak value detector 32, 42 Spreading code sequence selector 33, 34, 43 Switch

Claims (14)

[Claims] 1. A spread-spectrum communication relay transmission device for regenerating and relaying a transmission signal from a transmission source to a receiver, wherein the transmission signal is regenerated and relayed by using a spreading code sequence different from that at the time of reception when regenerating and relaying the transmission signal. A spread spectrum communication relay transmission device configured to transmit. 2. A spread code sequence used when regenerating and relaying a transmission signal from the transmission source to the receiver is selected from among characteristics orthogonal to the spread code sequence used when receiving the transmission signal and characteristics similar thereto. 2. The spread spectrum communication relay transmission device according to claim 1, wherein the spread code sequence has one of them. 3. The spread spectrum communication relay transmission apparatus according to claim 1, wherein the transmission signal from the transmission source is input from a transmitter via a communication satellite. 4. A spread spectrum communication relay transmission apparatus for regenerating and relaying a transmission signal from a transmission source to a receiver, comprising: a determination unit for determining a spread code sequence of the transmission signal from the transmission source; A transmission unit for transmitting after spreading using a spreading code sequence different from the spreading code sequence determined by the determining unit, and transmitting the spread code sequence. 5. The spread code sequence used by the transmission means is a spread code sequence having one of a characteristic orthogonal to the spread code sequence determined by the determination means and a characteristic similar thereto. The spread spectrum communication relay transmission device according to claim 4. 6. The spread spectrum communication relay transmission apparatus according to claim 4, wherein the transmission signal from the transmission source is input from a transmitter via a communication satellite. 7. A spread-spectrum communication relay transmission method for regenerating and relaying a transmission signal from a transmission source to a receiver, wherein the transmission signal is regenerated and relayed using a spreading code sequence different from that at the time of reception. A spread-spectrum communication relay transmission method characterized by transmitting. 8. A spreading code sequence used when a transmission signal from the transmission source is reproduced and relayed to the receiver, wherein a spreading code sequence orthogonal to the spreading code sequence used at the time of receiving the transmission signal and a characteristic similar thereto are used. The spread spectrum communication relay transmission method according to claim 7, wherein the spread code sequence has one side. 9. The spread spectrum communication relay transmission method according to claim 7, wherein the transmission signal from the transmission source is input from a transmitter via a communication satellite. 10. A spread spectrum communication relay transmission method for regenerating and relaying a transmission signal from a transmission source to a receiver,
Determining a spread code sequence of the transmission signal from the source, and transmitting the transmission signal after spreading using a different spread code sequence from the determined spread code sequence, Spread spectrum communication relay transmission method. 11. The spread code sequence used in the step of transmitting the transmission signal is a spread code sequence having one of a characteristic orthogonal to the determined spread code sequence and a characteristic similar thereto. The spread spectrum communication relay transmission method according to claim 10. 12. The spread spectrum communication relay transmission method according to claim 10, wherein the transmission signal from the transmission source is input from a transmitter via a communication satellite. 13. A recording medium storing a spread spectrum code sequence control program for causing a spread code sequence control unit to select a spread code sequence, wherein the spread spectrum code sequence control program is provided to the spread code sequence control unit. A recording medium storing a spread spectrum code sequence control program, wherein the transmission signal is spread using a different spread code sequence from that at the time of reception when the transmission signal is reproduced and relayed, and then transmitted. 14. A recording medium on which a spread code sequence control program for causing a spread code sequence control unit to select a spread code sequence is recorded, wherein said spread spectrum code sequence control program is transmitted to said spread code sequence control unit. A spreading code sequence of a transmission signal from the transmission source, and transmitting the transmission signal after spreading the transmission signal using a spreading code sequence different from the determined spreading code sequence. A recording medium that records a sequence control program.