JP2000124837A - Spread spectrum communication equipment, transmission equipment and reception equipment for spread spectrum communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent communication from being disabled, even when there are a large numbers of users. SOLUTION: This transmission equipment is composed of pattern generators 12 and 13 for generating different hopping patterns, synthesizers 14 and 15, to which these patterns are supplied for sending out the hopping patterns of different oscillation frequencies, primary modulator 11 for modulating an input signal into a narrow band, second modulator 26 for multiplying this primary modulated signal and the outputs of synthesizers 14 and 15 and sending out a spread modulated signal, and switching function for transmission power and the reception equipment is composed of pattern generators 22 and 23 of the same configuration as the transmission equipment, synthesizers 24 and 25, second demodulator 26 and first demodulator 28 for multiplying the hopping patterns of different oscillation frequencies from these synthesizers 24 and 25 and a reception signal and inversely spreading and demodulating them. Since the signal modulated into narrow band is communicated by a minimum transmission power while made to undergo double hopping at different frequencies, the collision of data can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention An ordinary radio signal is converted into a narrow-band modulated signal, and the converted signal is transmitted with a minimum transmission power of two.
The present invention relates to a spread-spectrum communication device, a spread-spectrum communication transmitting device, and a receiving device that perform wireless communication by heavy hopping.

[0002]

2. Description of the Related Art Spread spectrum communication systems include a direct sequence (DS) system and a frequency hopping (FH) system.

In the former DS method, as shown in FIG. 3, primary modulation (PSK: Phase Shift) is performed on transmission data by a primary modulator 41.
4 (a) is obtained from the output, and the primary modulation signal is multiplied with the PN sequence from the PN sequence generator 42 by the multiplier 43, as shown in FIG. 4
A spread signal shown in (b) is obtained, and this spread signal is supplied to the antenna 24.

[0004] In the latter FH system, a signal that is primary-modulated on the transmitting side is frequency-converted into a target frequency band, and the transmission frequency of the frequency synthesizer is switched one after another according to a certain pattern, thereby carrying the signal to be transmitted. On the other hand, on the receiving side, the receiving side switches the oscillation frequency of the frequency synthesizer in synchronization with the hopping pattern of the received wave, converts the frequency to a narrow band signal having a certain intermediate frequency, and the original modulated wave It is intended to be obtained.

In the FH system, as shown in FIG. 5, transmission data is subjected to primary modulation by a primary modulator 45 to obtain a primary modulation signal, and a hopping pattern generator is applied to the primary modulation signal. The output of 46 is output by a hopping synthesizer 47,
As shown in FIG. 6, the frequency hopping is performed and the product is multiplied by the multiplier 48.
Through the antenna 50.

[0006] For example, primary modulation signal as a PSK a (t) cos (ω 1 t) cos (ω 2 t) = a (t) co
s ｛(ω ₁ + ω ₂ ) t｝ / 2 + a (t) cos ｛(ω ₁ −ω ₂ )
t｝ / 2 By extracting only the necessary one of the first and second terms with the band-pass filter 49, the frequency can be converted into a carrier.

[0007]

When viewed in a short time, the spectrum of a modulated wave in the frequency hopping system has the same form as that of ordinary narrow-band modulation. (If the frequency of a narrow-band modulated signal is narrow-band modulated and the frequency is not hopped but the frequency is not hopped as in the case where the frequency is fixed at a fixed frequency, it becomes the same as a normal modulation method.) If it is slow, it will cause interference for users of narrowband communication. Also, if there are a large number of users using the frequency hopping scheme, communication from a plurality of users at a certain frequency will be superimposed, making communication impossible.

[0008] When wireless communication is performed in the same area, a problem such as interference occurs, and when data communication is performed with the maximum transmission power, other devices are affected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a spread spectrum communication apparatus and a spread spectrum communication apparatus which do not become unable to communicate even when there are a large number of users. A transmitting device and a receiving device are provided.

[0010]

SUMMARY OF THE INVENTION A spread spectrum communication apparatus according to the present invention comprises two hopping pattern generators for generating different hopping patterns, a pattern supplied from the generation of the hopping patterns, and a hopping pattern having a different oscillation frequency for each output. Two synthesizers to be transmitted, a primary modulator for modulating a signal to be transmitted, a primary modulation signal modulated by the primary modulator, and a hopping pattern of the different oscillation frequency are multiplied, and the output is spread. A second modulator for transmitting a modulated signal and a transmission device having a transmission power switching function, and two hopping pattern generators and two synthesizers formed in the same configuration as the hopping pattern generator and the synthesizer of the transmission device are provided. Hopping pattern of oscillation frequency transmitted from two synthesizers By multiplying the received signal which has received the radio wave transmitted from the transmitting apparatus and is characterized in that comprising a receiver including a demodulator for obtaining a demodulated signal to output to despreading.

[0011] Then, it is preferable to transmit the cyclic frame to the receiving side while switching the power on the transmitting side, and confirm the minimum communicable power.

Also, a band-pass filter for selecting a desired frequency is provided at the output of the second modulator of the transmitting device, and a band-pass filter having the same characteristics as the band-pass filter of the receiving device is provided for the receiving device. Is preferably selected and input to the demodulator.

In the transmitter for spread spectrum communication according to the present invention, two hopping pattern generators for generating different hopping patterns and patterns supplied from the generators are provided, and hopping patterns of different oscillation frequencies are supplied to respective outputs. Two synthesizers to be transmitted, a primary modulator that modulates a signal to be transmitted, and a hopping pattern having an oscillation frequency different from the primary modulation signal modulated by the primary modulator are multiplied and output. And a second modulator for transmitting a spread modulation signal.

Then, it is preferable to provide a band-pass filter for selecting a desired frequency at the output of the second modulator to be transmitted.

In the receiver for spread spectrum communication according to the present invention, two hopping generators for generating different hopping patterns, and patterns from the generators are supplied, and hopping patterns having different oscillation frequencies are transmitted to respective outputs. And a demodulator that multiplies the hopping pattern of the oscillating frequency transmitted from the two synthesizers and the received signal that has received the radio wave transmitted from the transmitting device, and despreads to obtain a demodulated signal at the output. It is characterized by consisting of.

The received signal may be supplied to a demodulator via a band-pass filter for selecting a desired frequency.

[0017]

FIG. 1 is a block diagram of a frequency double hopping spread spectrum communication apparatus according to an embodiment of the present invention.

FIG. 1A shows the configuration of the transmitting side.
11 is PSK or FSK for the digital input signal to be transmitted.
The primary modulators 12 and 13 generate primary hopping patterns and the primary and secondary hopping pattern generators 14 and 15 generate different hopping patterns. The hopping pattern is supplied, the frequency hops over the frequency range with time, and the hopping pattern having a different oscillation frequency is changed to the secondary modulator 16.
And a first and a second hopping synthesizer.

The secondary modulator 16 multiplies the primary modulated wave signal from the primary modulator 11 with hopping patterns of different oscillation frequencies sent from the first and second hopping synthesizers 14 and 15, and outputs the product. This is a modulator for transmitting a spread modulation signal. The output of the secondary modulator 6 is selected by a band-pass filter (not shown) for selecting a desired frequency.
The selected spread modulation signal is transmitted from the antenna 17.

The transmitting side is provided with a function of receiving a reply signal from the receiving side and, when the reply signal does not return from the receiving side for a certain time, increasing the transmission power again and transmitting the spread modulated signal. ing.

FIG. 1B shows a configuration on the receiving side. A band-pass filter 21 selects a desired frequency of the spread modulated wave signal received by the antenna 20 and outputs it to the secondary demodulator 26. Reference numerals 22 and 23 denote first and second hopping pattern generators for generating different hopping patterns synchronized with the transmission side, respectively, and reference numerals 24 and 25 each receive a pattern from the pattern generators 22 and 23 and output a different oscillation wave number. Are the first and second hopping synthesizers for transmitting the hopping pattern to the secondary demodulator 26.

The secondary demodulator 26 multiplies the hopping patterns sent from the first and second hopping synthesizers 24 and 26 by the received signal from the band-pass filter 11, despreads, and performs secondary demodulation on the output. It is a demodulator that outputs a signal.

Reference numeral 27 denotes a band-pass filter for selecting a desired frequency of the output of the secondary demodulated signal. Reference numeral 28 denotes a primary demodulation of the secondary demodulated wave signal from the band-pass filter 17 to produce an output signal similar to the transmission-side input signal. This is the primary demodulator that outputs. The receiving side has a function of transmitting a reply signal to the transmitting side when a transmission signal is received.

The operation of the above embodiment will be described.
The transmitting side transmits the digital input signal to the primary modulator 1
1 and is supplied to the secondary modulator 16. The first and second hopping pattern generators 12 and 13 generate different hopping patterns, and the first and second hopping synthesizers 14 and 15 to which the hopping patterns are supplied are provided.
Hopping patterns of different frequencies
To supply.

The hopping pattern having a frequency different from that of the primary modulation signal is multiplied by the secondary modulator 16 and spread-modulated. When a series of the above operations is observed while following the change in the oscillation frequency on the time axis, a pattern as shown in FIG. 2 is obtained. The spread-modulated signal is transmitted as a radio wave from the antenna 17 via a band-pass filter having an appropriate frequency with minimum power.

Here, when the reply signal does not return from the receiving side for a certain time, the transmission power is increased again and the same operation is repeated. The series of operations from the primary modulation to the transmission generates and transmits only the cyclic frame on the receiving side with each settable transmission power. Check the power that can not be transmitted at this time,
The data is transmitted between the transmission and reception at the previous transmission power.

When the receiving side receives the transmission signal, the signal is transmitted to a band-pass filter 2 for selecting a desired frequency.
1 is supplied to the secondary demodulator 26. And the first,
The second hopping pattern generators 22 and 23 generate different hopping patterns synchronized with the transmitting side, and the first and second hopping synthesizers 24 and 25 having the same frequency as the frequency used on the transmitting side to which the pattern is supplied are supplied with different frequencies. Is supplied to the secondary modulator 26.

The hopping pattern of a frequency different from the frequency of the signal received from the band-pass filter 21 is
6 and outputs a despread demodulated signal. This despread demodulated signal is passed through the band-pass filter 27 to the primary demodulator 2.
The signal is subjected to primary demodulation at 8 and becomes an output signal similar to the transmission side entrance signal.

[0029]

Since the present invention employs the frequency double hopping method as described above, the following effects can be obtained.

(1) Since data communication is performed with the minimum transmission power, not only the influence on other devices but also the problem of interference and the like when performing multiple access is eliminated.

(2) When the number of simultaneous users using the frequency hopping system is very large, by using different frequencies at the same time, collision between data can be avoided and communication becomes possible.

(3) Since the spectrum of the transmission wave is spread, the power density is also reduced.

(4) Even if the presence of a signal is detected, no information is restored unless the hopping pattern is notified.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a frequency double hopping method according to an embodiment, where (a) is a block diagram showing a configuration on a transmission side. (B) is a block diagram showing a configuration on the receiving side.

FIG. 2 is a diagram showing a hopping pattern of an oscillation frequency in which a frequency-hopping signal is represented by time and frequency.

FIG. 3 is a block diagram showing a configuration of a transmission side of a direct spreading system according to a conventional example.

FIG. 4 shows a signal waveform of the direct spreading method.
(A) is a primary modulation signal waveform diagram, (b) is a spread signal waveform diagram.

FIG. 5 is a block diagram showing a transmission-side configuration of a frequency hopping system according to a conventional example.

FIG. 6 is a waveform chart showing a frequency hopping signal.

[Explanation of symbols]

 11 ... primary modulator 12, 13 ... hopping pattern generator 14, 15 ... hopping synthesizer 16 ... secondary modulator, spreading modulator 21, 27 ... bandpass filter 22, 23 ... hopping pattern generator 24, 25 ... hopping Synthesizer 26 ... Secondary modulator, despread modulator 28 ... Primary demodulator

Claims (7)

[Claims] 1. generating a different hopping pattern;
Two hopping pattern generators, two synthesizers to which patterns are supplied from the generator, each of which sends out a hopping pattern having a different oscillation frequency to an output, a primary modulator for modulating a signal to be transmitted, and a primary modulation A second modulator for multiplying the primary modulation signal modulated by the modulator with the hopping pattern having the different oscillation frequency and transmitting a spread modulation signal to an output, and a transmission device having a transmission power switching function; Having two hopping pattern generators and two synthesizers formed in the same configuration as the hopping pattern generator and the synthesizer described above, the hopping pattern of the oscillation frequency transmitted from the two synthesizers and the radio wave transmitted from the transmitting device are A demodulator that multiplies the received signal and despreads to obtain a demodulated signal at the output; A spread spectrum communication apparatus, comprising: a receiving apparatus having: 2. The spread spectrum communication apparatus according to claim 1, wherein the transmitting side transmits the cyclic frame to the receiving side while switching the power, and checks a minimum communicable power. 3. The transmission device according to claim 1, further comprising a band-pass filter for selecting a desired frequency at an output of the second modulator of the transmission device, wherein the reception device has the same characteristics as the band-pass filter of the reception device. A spread spectrum communication apparatus comprising a band-pass filter, a desired frequency selected and input to a demodulator. 4. Generating different hopping patterns 2
Two hopping pattern generators, and two synthesizers to which patterns from the generator are supplied and which transmit hopping patterns having different oscillation frequencies to respective outputs,
A second modulator for transmitting a spread modulation signal to an output by multiplying a primary modulator for modulating a signal to be transmitted and a hopping pattern having an oscillation frequency different from that of the primary modulation signal modulated by the primary modulator; A transmitter for spread spectrum communication, comprising: a modulator. 5. The transmission device for spread spectrum communication according to claim 4, wherein a band-pass filter for selecting a desired frequency is provided at an output of the second modulator. 6. Generating different hopping patterns
Two hopping generators, two synthesizers that are supplied with the pattern from the generator and transmit hopping patterns of different oscillating frequencies to the output, and hopping patterns of the oscillating frequency transmitted from the two synthesizers and transmitted from the transmitting device. And a demodulator that multiplies the received radio wave by a received signal and despreads to obtain a demodulated signal at the output. 7. The receiver for spread spectrum communication according to claim 6, wherein the received signal is supplied to a demodulator via a band-pass filter for selecting a desired frequency.