JPH0738468A - Spread spectrum communication equipment - Google Patents

Abstract

PURPOSE:To attain high speed frequency hopping with simple configuration by allowing a transmitter side to phase-modulate a direct spread signal in response to a 1 logical state or a combined logical state of plural bits of transmission data and reproducing the transmitter side data by pattern matching in the direct spread demodulation of the receiver side. CONSTITUTION:A matched filter 12 selects a direct pattern A when a logical state is '1' and a matched filter 13 selects a direct pattern B when a logical state is '0'. When an input signal, that is, an output of a mixer 10, that is, a frequency hopping demodulation signal is a pattern A, then the filter 12 outputs a coincidence signal, and conversely when the input signal is a pattern B, the filter 13 outputs a coincidence signal. A data discrimination circuit 14 outputs a synchronizing signal to a synchronization detection circuit 15 every time the coincidence signal is provided from the two matched filters to establish the synchronization of the frequency hopping demodulation stage. As a result, the data discrimination circuit 14 reproduces the transmission data.

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 using a hybrid system of a direct spread system and a frequency hopping system.

[0002]

2. Description of the Related Art In a spread spectrum communication device based on a hybrid system of a direct spread system and a frequency hopping system, conventionally, on the transmitting side, direct spread is applied to transmission data and phase modulation (PSK) is performed on the transmission data to perform frequency hopping. There are a type (FIG. 2) and a type (FIG. 3) that directly spreads transmission data and frequency-modulates (FSK) it to perform frequency hopping.

In the spread spectrum communication apparatus shown in FIG. 2, the transmitting side includes a synchronization frame generator 21, a direct spread (DS) pattern generator 22, a mixer 23 and a PS.
A K modulator 24, a frequency hopping (FH) pattern generator 25, a frequency hopping (FH) synthesizer 26, a mixer 27, and a transmitting antenna 28 are basically provided.

On the receiving side, the receiving antenna 29, the mixer 30, the FH synthesizer 31, the synchronization detecting circuit 32, F
An H pattern generator 33, a DS pattern generator 34, a PSK demodulator 35, a mixer 36, and a frame regenerator 37 are basically provided.

First, on the transmitting side, the data to be transmitted is
A synchronization signal is inserted by the synchronization frame generator 21 and is input to one side of the mixer 23. The synchronization signal is inserted for the convenience of checking the absolute phase during demodulation.
On the other hand, the DS pattern generator 22 generates a predetermined DS pattern designated by the transmission channel information given from the outside and gives it to the other input of the mixer 23.

That is, the data in which the sync signal is inserted is directly spread by the mixer 23 by the DS pattern, and the PSK
It is phase-modulated (PSK) by the modulator 24 and is one input of the mixer 27.

Further, in the FH pattern generator 25, the frequency designated by the transmission channel information given from the outside (arbitrary frequency different for each cycle of the DS pattern)
Of the FH pattern is generated. The FH synthesizer 26 generates a frequency signal according to this FH pattern and supplies it to the other input of the mixer 27.

That is, the PSK-modulated direct sequence signal is
The mixer 27 performs frequency hopping with a frequency signal according to the FH pattern, and the signal is wirelessly transmitted from the transmitting antenna 28.

Next, on the receiving side, the signal received by the receiving antenna 29 is fed by the mixer 30 to the FH synthesizer 31.
The frequency signal is subjected to frequency hopping demodulation by the frequency signal from and input to the synchronization detection circuit 32 and the PSK demodulator 35.

In the synchronization detection circuit 32, a timing signal synchronized with the input signal (transmission signal) is generated by the matched filter processing, and the timing signal is given to the FH pattern generator 33 and the DS pattern generator 34.

The FH pattern generator 33 generates a hopping pattern of a frequency designated by externally provided reception channel information. This is the same as that generated by the transmitter 25, and is generated in synchronization with the FH pattern on the transmitter side by the timing signal.

Therefore, the FH synthesizer 31 generates the same thing as the one generated by the transmitting side 26 in synchronization, and the synchronization is established by the repeated operation of 31 → 30 → 32 → 33 → 31, Since the frequency hopping demodulation is correctly performed in the mixer 30, the PSK demodulator 35 demodulates the output (direct spread signal) of the mixer 23 on the transmission side,
It is applied to one input of the mixer 36.

In the DS pattern generator 34, a predetermined DS specified by externally received channel information is designated.
A pattern is generated and applied to the other input of mixer 36.
This is the same as that generated by the sender 22.

Thus, in the mixer 36, the transmitter 21
Since the data signal having the same content as the output (transmission data in which the synchronization signal is inserted) is directly spread and demodulated and output, the frame generator 37 reproduces the transmission data using the synchronization signal.

Next, in the spread spectrum communication apparatus shown in FIG. 3, the transmitting side basically comprises a mixer 41, a DS pattern generator 42, an FSK modulator 43, an FH pattern generator 44, an FH synthesizer 45, a mixer 46 and a transmitting antenna 47. Prepare for

On the receiving side, the receiving antenna 48, the mixer 49, the FH synthesizer 50, the synchronization detecting circuit 51, F
The H pattern generator 52, the DS pattern generator 53, the FSK demodulator 54, and the mixer 55 are basically provided.

In the spread spectrum communication device shown in FIG. 3, the modulation format of the transmission spread signal is the FSK system, and as a result, the synchronization frame generator 21 and the frame regenerator 37 in the spread spectrum communication device shown in FIG. The basic operation is the same except that there is no.

As described above, in the hybrid spread spectrum communication apparatus, the receiving side can perform data demodulation in synchronization if both the DS pattern and the FH pattern match the transmitting side. Since it is not possible to demodulate data when the values are different, it is possible to secure confidentiality for a device other than a transmitter / receiver with a known communication pattern.

[0019]

The above-described conventional spread spectrum communication apparatus using the hybrid system has the following problems. First, in the spread spectrum communication device shown in FIG. 2, since the phase becomes discontinuous with each frequency hopping, a synchronization signal is required to know the relationship between the absolute phase and the transmission data “1” or “0”. However, there is a problem that the occupied bandwidth of data is widened and the efficiency of use of frequency is lowered in that a signal unrelated to data is also transmitted.

On the other hand, low-speed frequency hopping (a method of transmitting a plurality of data for each frequency hopping) must be adopted in order to reduce the ratio of the synchronization signal to the transmission data and increase the frequency efficiency. There is also a problem that the confidentiality of communication is deteriorated due to the decrease.

Further, in the spread spectrum communication device shown in FIG. 3, the FSK modulator cannot be constructed by only a mixer like the PSK modulator, so that the modulator or demodulator will not operate when the direct spread rate becomes tens or hundreds of Mbps. High-speed operation is required, which results in problems such as complication of the device and increase in power consumption.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a spread spectrum communication apparatus of a hybrid system that enables high-speed frequency hopping without complicating the configuration.

[0023]

In order to achieve the above object, the spread spectrum communication apparatus of the present invention has the following configuration. That is, in the spread spectrum communication apparatus of the present invention, the transmission side includes a plurality of pattern generators that generate mutually different direct spread patterns; A circuit for selecting outputs of corresponding ones of a plurality of pattern generators; a PSK modulator for performing PSK processing on the selected direct spread pattern and transmitting the PSK modulator to a frequency hopping stage. A plurality of matched filters that receive the outputs of the stages in parallel and perform pattern matching with corresponding ones of the plurality of preset direct diffusion patterns; A circuit that outputs the synchronization signal to the frequency hopping demodulation stage and demodulates and outputs the data. Is provided.

[0024]

Next, the operation of the spread spectrum communication device of the present invention configured as described above will be described. On the transmission side, for example, two pattern generators for respectively generating direct diffusion patterns of A and B are provided, and when the logical state of 1 bit of transmission data is "1", the direct diffusion pattern A is selected,
When the logic state is “0”, the direct spread pattern B is selected, and PSK processing is performed on each direct spread signal,
After that, frequency hopping is performed by the same configuration as the conventional one, and wireless transmission is performed.

On the receiving side, first, frequency hopping demodulation is performed by the same configuration as in the prior art, and the signals are input in parallel to the two matched filters according to the present invention, and the direct matching patterns of A and B are matched and the frequency hopping is performed. A synchronization signal is generated for the demodulation stage, and transmission data is reproduced by establishing synchronization.

In short, on the transmitting side, the direct spread signal is set to P
Although SK modulation is performed, in direct spread demodulation on the receiving side, transmission data can be reproduced by pattern matching without considering the phase of the data. Therefore, the conventional synchronization signal for absolute phase determination is not required, and high-speed frequency hopping for hopping one bit of data at one or more frequencies is possible without complicating the configuration.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a spread spectrum communication device according to an embodiment of the present invention. The apparatus of the present embodiment uses different direct diffusion (DS) depending on the logical state of each bit of transmission data.
It is a method of direct diffusion in a pattern.

That is, in FIG. 1, the transmission side is basically provided with the DS pattern generators 1 and 2, the selection circuit 3, the PSK modulator 4, the FH pattern generator 5, the FH synthesizer 6, the mixer 7 and the transmission antenna 8. .

The receiving side has a receiving antenna 9 and a mixer 1.
0, FH synthesizer 11, matched filter 12, same 13, data judgment circuit 14, synchronization detection circuit 15 and FH
The pattern generator 16 is basically provided.

First, on the transmitting side, the two DS pattern generators generate mutually different direct spread codes (DS patterns) according to the designation of transmission channel information given from the outside. For example, the DS pattern generator 1 generates the DS pattern A and the DS pattern generator 2 generates the DS pattern B.

The selection circuit 3 selects the DS pattern A when the logic state is "1" and the DS pattern B when the logic state is "0" for each bit of the data to be transmitted. To the PSK modulator 4.

The PSK modulator 4 inputs D in time series.
PSK processing is performed on both the direct spread signals of the S pattern A and the DS pattern B.

This PSK signal is frequency hopped by the frequency hopping stage (5, 6, 7) having the same structure as the conventional one, and is wirelessly transmitted from the transmitting antenna 8. At this time, high-speed frequency hopping can be performed in which a plurality of frequencies are assigned for each DS pattern, that is, for each bit of data.

Next, on the receiving side, the received signal of the receiving antenna 9 has a frequency hopping demodulation stage (1
0, 11, 16, 15) and becomes the same signal as the signal directly spread on the transmission side (output of PSK modulator 4) and input in parallel to the two matched filters 12 and 13.

Here, the matched filter 12 and the same 13
Selects one different DS pattern from a plurality of preset matching DS patterns in accordance with designation of externally received channel information, and selects the selected matching DS pattern and the input DS pattern, respectively. Is determined and the coincidence signal is output to the data determination circuit 14.

Specifically, for example, the matched filter 12
Selects the DS pattern A and the matched filter 13 selects D
If S pattern B is selected, the input signal (mixer 1
If the output of 0, that is, the frequency hopping demodulation signal) is the DS pattern A, the matched filter 12 outputs a match signal, and the matched filter 13 outputs nothing to the input signal at this time.

On the contrary, if the input signal is the DS pattern B, the matched filter 13 outputs a matched signal, and the matched filter 12 does not output anything with respect to the input signal at this time.

In the data decision circuit 14, the sync detection circuit 1 is activated each time a match signal is input from the two matched filters.
The sync signal is output to the signal 5. This establishes the synchronization of the frequency hopping demodulation stage as in the conventional case. as a result,
In the data determination circuit 14, when the match signal is input from the matched filter 12, the output is set to “1”, and when the match signal is input from the matched filter 13, the output is set to “0”.
The transmission data can be reproduced by repeating the above procedure.

In this embodiment, two DS patterns corresponding to two logical states of 1 bit of data are used. However, for example, four combined logical states of 2 bits of data ("0
It is also possible to use a plurality of DS patterns according to the combination logic state of a plurality of data bits, such as using four DS patterns corresponding to 0 "," 01 "," 10 "," 11 "). By doing so, the confidentiality can be further improved.

[0040]

As described above, the spread spectrum communication apparatus of the present invention PSK-modulates the direct spread signal according to the 1-bit logical state of transmission data or the combined logical state of a plurality of bits on the transmitting side. , In the direct spread demodulation on the receiving side, the transmission data can be reproduced by pattern matching without considering the phase of the data.
A PSK modulator is used on the transmission side, but the conventional synchronization signal for absolute phase determination can be eliminated, and high-speed frequency hopping for hopping one bit of data at one or more frequencies without complicating the configuration. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an embodiment of a spread spectrum communication apparatus of the present invention.

FIG. 2 is a configuration block diagram of a conventional spread spectrum communication device.

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

[Explanation of symbols]

 1 Direct Spread (DS) Pattern Generator 2 Direct Spread (DS) Pattern Generator 3 Selection Circuit 4 PSK Modulator 5 Frequency Hopping (FH) Pattern Generator 6 Frequency Hopping (FH) Synthesizer 7 Mixer 8 Transmit Antenna 9 Receive Antenna 10 Mixer 11 Frequency Hopping (FH) synthesizer 12 Matched filter 13 Matched filter 14 Data determination circuit 15 Sync detection circuit 16 Frequency hopping (FH) pattern generator

Claims (1)

[Claims] 1. A plurality of pattern generators for generating direct diffusion patterns different from each other on the transmitting side; a plurality of pattern generators for generating a direct diffusion pattern different from each other; A circuit for selecting the output of the corresponding one; and a PSK modulator for performing PSK processing on the selected direct spread pattern and sending it to the frequency hopping stage, and the receiving side outputs the outputs of the frequency hopping demodulation stage in parallel. A plurality of matched filters for receiving pattern matching with corresponding ones of the plurality of direct diffusion patterns set in advance; and receiving the outputs of the plurality of matched filters to the frequency hopping demodulation stage. A circuit for outputting a synchronization signal and demodulating and outputting data; Kutoramu diffusion communication device.