JPH10145263A - Spread spectrum communication device, transmitter and receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stop interference and also to prevent communication from plural users from being disabled. SOLUTION: A digital signal to be transmitted is inputted to a primary modulator 11, and a signal inputted here undergoes primary modulation in a narrow-band modulation system. A primary modulation signal that is modulated by the modulator 11 is supplied to a diffusion modulator 12. A pattern which is generated by 1st and 2nd hopping pattern generators 13A and 13B is inputted to 1st and 2nd hopping synthesizes 14A and 14B, in which a frequency hops in a wide frequency range with respect to time. When the pattern is inputted, the synthesizers 14A and 14B acquire a hopping pattern of an oscillation frequency in an output. The acquired hopping pattern is supplied to the modulator 12, where it is multiplied by the 1st modulation signal and later it is emitted as a radio wave from an antenna 16, via a band-pass filter of a suitable frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spread spectrum communication apparatus, a transmission apparatus, and a reception apparatus for converting a normal radio signal into a narrow-band modulated signal and hopping the converted signal twice to perform wireless communication. .

[0002]

2. Description of the Related Art Spread spectrum communication systems include direct spread (DS) and frequency hopping (FH) systems. In the former DS system, when primary data (PSK: Phase Shift Keying) is applied to transmission data by a primary modulator 41 as shown in FIG. 4, a primary modulated signal shown in FIG.
When this primary modulation signal is multiplied by a PN sequence from a PN sequence generator 42 by a multiplier 43, a spread signal shown in FIG. 5B is obtained, and this spread signal is supplied to an antenna 44.

[0003] In the latter FH system, a signal that has been primary-modulated on the transmission side is frequency-converted into a target frequency band, and the transmission frequency of a frequency synthesizer is switched one after another according to a certain pattern, so that the carrier frequency of the signal to be transmitted is changed. On the other hand, on the receiving side, the oscillation frequency of the frequency synthesizer is switched in synchronization with the hopping pattern of the received wave, and the frequency is converted to a narrow-band signal with a certain intermediate frequency to obtain the original modulated wave. It is intended to be.

In the FH system, as shown in FIG. 6, transmission data is subjected to primary modulation by a primary modulator 61 to obtain a primary modulation signal on an output, and a hopping pattern generator 62 The output is output by a hopping synthesizer 63 in FIG.
As shown in FIG. 6, the frequency hopping is performed, the product is multiplied by a multiplier 64, and then supplied to an antenna 66 through a band-pass filter 65 of an appropriate frequency.
For example, let a (t) cos (ω ₁ t) be the primary modulation signal as PSK,
Further, the output signal of the hopping synthesizer 63 is represented by cos (ω
When ₂ t) to the output of the multiplier 64 is expressed by the following equation.

A (t) cos (ω ₁ t) cos (ω ₂ t) = a (t) cos ｛(ω ₁
+ Ω ₂ ) t｝ / 2 + a (t) cos ｛(ω ₁ −ω ₂ ) t｝ / 2 Only the required one of the first and second terms is extracted by the band-pass filter 65 so that the carrier wave is obtained. Can be converted.

[0006]

As described above, there are two types of spread spectrum communication systems. However, the spectrum of a modulated wave in the latter FH system is, when viewed in a short time, a normal narrow band modulation. It becomes the same shape.
If the hopping speed is slow, there is a possibility that interference will occur for users of narrowband communication. Also, F
If there are a large number of users using the H method, there is a problem that communication from a plurality of users at a certain frequency overlaps and communication becomes impossible.

The present invention has been made in view of the above circumstances, and provides a spread spectrum communication apparatus, a transmission apparatus, and a reception apparatus that eliminate interference and prevent communication from a plurality of users. That is the task.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, a first aspect of the present invention provides a first and second hopping pattern generators for generating different hopping patterns,
A pattern from the generator is supplied, and first and second synthesizers for outputting hopping patterns having different oscillation frequencies to an output, a primary modulator for modulating a signal to be transmitted, and a primary modulator for modulating the signal to be transmitted. A transmission device having a second modulator that multiplies the next modulation signal and the hopping pattern having the different oscillation frequency and sends out a spread modulation signal to an output;
Oscillation frequencies transmitted from the first and second synthesizers, having first and second hopping pattern generators and first and second synthesizers formed in the same configuration as the hopping pattern generator and the synthesizer of the transmission device And a demodulator that multiplies a hopping pattern of the above and a received signal that has received a radio wave transmitted from the transmitting device, and despreads to obtain a demodulated signal at an output. It is.

According to a second aspect of the present invention, a band-pass filter for selecting a desired frequency is provided at an output of a second modulator of the transmitting device, and the same band-pass filter as that of the transmitting device is provided for the receiving device to adjust a desired frequency. It is characterized by being selected and input to the demodulator.

According to a third aspect of the present invention, there are provided first and second hopping pattern generators for generating different hopping patterns, and first and second hopping patterns which are supplied with patterns from the generators and output hopping patterns having different oscillation frequencies to an output. 2 synthesizer, a primary modulator for modulating a signal to be transmitted, a primary modulation signal modulated by the primary modulator, and a hopping pattern having a different oscillation frequency are multiplied, and a spread modulation signal is output to an output. And a second modulator for transmitting.

A fourth invention is characterized in that a band-pass filter for selecting a desired frequency is provided at the output of the second modulator.

According to a fifth aspect of the present invention, there are provided first and second hopping pattern generators for generating different hopping patterns, and first and second hopping patterns which are supplied with patterns from the generator and output hopping patterns having different oscillation frequencies to an output. Demodulator which multiplies a 2 synthesizer by a hopping pattern of an oscillation frequency transmitted from the first and second synthesizers and a received signal which receives a radio wave transmitted from a transmitting device, and despreads to obtain a demodulated signal at an output. And a container.

A sixth invention is characterized in that the received signal is supplied to a demodulator via a band-pass filter for selecting a desired frequency.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a transmitting side showing a first embodiment of the present invention. In FIG. 1, a digital signal to be transmitted to a primary modulator 11 is input, and the input signal is added to a PSK signal. Or 1 in FSK narrowband modulation
Apply next modulation. The primary modulation signal modulated by the primary modulator 11 is supplied to a secondary modulator 12 that performs spread modulation. 1
Reference numerals 3A and 13B denote first and second hopping pattern generators for generating different hopping patterns.
The patterns generated by the hopping pattern generators 13A and 13B are first and second hopping synthesizers 14 whose frequencies hop over a wide frequency range with time.
A, 14B.

First and second hopping synthesizers 14
A and 14B output the pattern shown in FIG.
The hopping pattern of the oscillation frequency as shown in FIG. The obtained hopping pattern is the same as that of the secondary
After being multiplied by the primary modulation signal, and then passed through a band-pass filter 15 of an appropriate frequency to the antenna 1.
6 is radiated as radio waves.

In the first embodiment configured as described above, the digital signal to be transmitted is primary-modulated by the primary modulator 11, and the primary modulated signal is sent to the output. The primary modulation signal is multiplied by the secondary modulator 12 with the output signals of the first and second hopping synthesizers 14A and 14B, and
The carrier frequency of the next modulated signal is converted to any other frequency. The output signal of the secondary modulator 12 is a bandpass filter 1
5 from the antenna 16.

FIG. 3 is a block diagram of a receiving side showing a second embodiment of the present invention. A signal received by an antenna 31 is input to a band-pass filter 32, where a desired frequency is output. The output signal is despread 2
It is supplied to the next demodulator 33. Reference numerals 34A and 34B denote first and second hopping pattern generators for generating a hopping pattern synchronized with the transmitting side. The patterns generated by the first and second hopping pattern generators 34A and 34B are the frequencies used on the transmitting side. When the signals are input to the first and second hopping synthesizers 35A and 35B having the same frequency as the above, the hopping pattern of the oscillation frequency shown in FIG. 2 is obtained at the output. This hopping pattern is input to the secondary demodulator 33 and multiplied with the received signal, and then primary-demodulated by the demodulator 37 through the band-pass filter 36.

[0018]

As described above, according to the present invention,
When the number of simultaneous users using the frequency hopping method is over, by using different frequencies at the same time, communication can be avoided while avoiding collisions, and the probability of the worst collision can be reduced. Also,
Since the spectrum of the transmission wave is spread, the power density is reduced, and there is an advantage that even if the presence of a signal is detected, information cannot be restored unless the hopping pattern is known.

[Brief description of the drawings]

FIG. 1 is a block diagram of a transmitting side showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a hopping pattern of an oscillation frequency.

FIG. 3 is a block diagram on the receiving side showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a direct spread system in a spread spectrum communication system.

FIG. 5 is an explanatory diagram of a primary modulation signal and a spread signal.

FIG. 6 is a configuration diagram of a frequency hopping scheme in a spread spectrum communication scheme.

FIG. 7 is a diagram illustrating the principle of a frequency hopping operation.

[Explanation of symbols]

11 Primary modulator 12 Spread modulator 13A, 13B, 34A, 34B First and second hopping pattern generator 14A, 14B, 35A, 35B First and second hopping synthesizer 15, 32, 36 Band Pass filter 16, 31 Antenna 33 Despread demodulator 37 ... Demodulator

Claims (6)

[Claims] 1. First and second hopping pattern generators for generating different hopping patterns, first and second synthesizers for receiving patterns from the generators and transmitting hopping patterns having different oscillation frequencies to an output, and transmitting. A primary modulator for modulating a signal to be modulated, a second modulator for multiplying the primary modulation signal modulated by the primary modulator with the hopping pattern having the different oscillation frequency, and transmitting a spread modulation signal to an output. And a first and second hopping pattern generator and first and second synthesizers formed in the same configuration as the hopping pattern generator and the synthesizer of the transmission device. The hopping pattern of the oscillation frequency transmitted from the synthesizer is multiplied by the received signal that has received the radio wave transmitted from the transmitter, and despread. Spread spectrum communication apparatus characterized by comprising a receiver including a demodulator for obtaining a demodulated signal to output Te. 2. A band-pass filter for selecting a desired frequency is provided to an output of a second modulator of the transmitting device, and a band-pass filter is provided in the receiving device to select a desired frequency. 2. The spread spectrum communication apparatus according to claim 1, wherein the signal is input to a demodulator. 3. First and second hopping pattern generators for generating different hopping patterns, and first and second synthesizers to which patterns from the generators are supplied and for outputting hopping patterns having different oscillation frequencies to an output. ,
A second modulator that modulates a primary modulator that modulates a signal to be transmitted, a primary modulation signal modulated by the primary modulator, and a hopping pattern having a different oscillation frequency, and outputs a spread modulation signal to an output. A transmitter comprising a modulator. 4. The transmission device according to claim 3, wherein a band-pass filter for selecting a desired frequency is provided at an output of said second modulator. 5. First and second hopping pattern generators for generating different hopping patterns, and first and second synthesizers to which patterns from the generators are supplied and output to output hopping patterns having different oscillation frequencies. ,
A demodulator which multiplies the hopping pattern of the oscillation frequency transmitted from the first and second synthesizers by the reception signal received from the transmission device and receives the radio wave transmitted from the transmission device, and despreads to obtain a demodulated signal at the output. A receiving device, characterized in that: 6. The receiving apparatus according to claim 5, wherein the received signal is supplied to a demodulator via a band-pass filter for selecting a desired frequency.