JPH09298494A - Spread code generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spread code generation device in which a spread code with high randomness is generated and a frequency table is rewritten without interrupting communication. SOLUTION: An address information generator 6 generates address information and switching timing information based on a noise code from an A/D converter 5. A buffer 7 gives the address information to a frequency information generating section 8 as a address signal, in which addresses are designated at random according to noise codes by thermal noise and frequency information is sequentially read. Frequency tables 9, 10 write the frequency information sequentially and provides an output of the stored frequency information at a frequency hopping period based on an M series pseudo noise code from an M series code generator 2 via a switch 11. The output from the frequency tables 9, 10 is selected based on switch timing information and the frequency table not in use is rewritten into new frequency information.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a spread code generator, and more particularly to a spread code generator applied to a radio transmission apparatus using frequency hopping as a spread spectrum modulation method.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing an example of a conventional spread code generator and a table used for the same. This conventional spread code generator is a spread code generator that is applied to a wireless transmission device using frequency hopping as a spread spectrum modulation method. As shown in FIG. It comprises an M-sequence code generator 2 and a frequency table 21 as a memory. As shown in FIG. 5B, the frequency table 21 stores predetermined frequency information at each address.

The operation of this conventional spread code generator will be described with reference to the time chart of FIG. 5. The frequency hopping clock generated by the frequency hopping clock generator 1 shown in FIG. It is supplied to an M-sequence code generator 2, where an M-sequence pseudo-noise code is generated for each frequency hopping cycle, as schematically shown in FIG. The M-sequence pseudo-noise code is supplied as an address to the frequency table 21, and the stored frequency information is read out as a spread code as shown in FIG.

[0004] Here, the M-sequence is a cyclic code.
A code in which the check polynomial H (X) is a primitive polynomial,
It is generated by an n-stage linear feedback shift register and has a period of 2
^n- 1 series. For example, a 9-stage M-sequence is 511
(= 2 ⁹ -1) The same pattern is circulated every bit.

Further, in the conventional spread code generator, the frequency is f based on a predetermined frequency hopping (FH) pattern, which corresponds to the bits of the transmission data SD, for example, a frequency switching pattern according to the Reed-Solomon code. =
A configuration using an FH code generator that outputs an angular velocity ω given as ω / (2π) is known (Japanese Patent Laid-Open No. 4-540).
No. 33). Further, as another conventional spread code generating apparatus, a transmission signal of a frequency f _{0 at} a time t ₀ , a transmission signal of a frequency f ₁ at a time t ₁ , and so on, according to a predetermined hopping pattern. There is also known a configuration in which it is changed (Japanese Patent Application Laid-Open No. 64-48).
No. 545).

[0006]

However, FIG. 5 (A)
In the conventional spread code generator shown in FIG. 5, the information in the frequency table 21 is a predetermined pair of an address and frequency information as shown in FIG. It is possible to obtain only randomness equivalent to. This is because if the information in the frequency table 21 does not change, the output spread code is repeated every cycle of the M sequence as shown in FIG. 6 (C).

[0007] Further, the above-mentioned conventional spreading code generating apparatus includes:
Since there is no means for rewriting the frequency table 21 while performing wireless transmission in a state where the wireless devices are synchronized by frequency hopping, even if the information on the frequency table 21 can be rewritten, It is necessary to temporarily suspend communication and rewrite the information of the frequency table of the spread code generator incorporated in each wireless device with a setting device or the like, and to set the frequency table 21 without interrupting communication. Can not.

Further, in the conventional spread code generator described in Japanese Patent Laid-Open No. 4-54033, the FH pattern output from the FH code generator is repeated at regular intervals because a predetermined pattern is used. It is. Further, in the conventional spread code generator described in Japanese Patent Application Laid-Open No. 64-48545, the transmission frequency is merely changed according to a predetermined hopping pattern, and there is a problem that randomness is lacking.

[0009] The present invention has been made in view of the above points,
It is an object of the present invention to provide a spreading code generator capable of generating a spreading code with high randomness.

Another object of the present invention is to provide a spread code generator capable of rewriting a frequency table without interrupting communication.

[0011]

In order to achieve the above object, the present invention provides a pseudo-noise code generating means for generating a pseudo-noise code at each frequency hopping period, and a binary noise code from noise existing in the natural world. Noise code generating means for generating;
Based on the noise code generated by the noise code generation means,
Information creating means for creating address information and switching timing information for creating a frequency table, frequency information generating means for generating frequency information based on the address information and switching timing information created by the information creating means, and frequency information generating means. When the generated frequency information is input, the frequency information is written in the sequential address. When the pseudo noise code generated by the pseudo noise code generation means is input as an address signal, the written frequency information is frequency hopped. A pseudo-noise code is supplied to one of the first and second frequency tables read out for each cycle and one of the first and second frequency tables, and frequency information read out for each frequency hopping cycle is output as a spread code. And the other of the second frequency table, the frequency generated by the frequency information generating means. Writes the number information to the sequential address, is obtained by a configuration having a switching control means for alternately switching a frequency table to write the frequency table and the frequency information for supplying pseudo noise code based on the switching timing information.

That is, according to the present invention, it is necessary to generate frequency information in a random order based on address information and switching timing information generated from noise existing in nature and store the frequency information in a frequency table. A frequency table that repeats the frequency table, supplies a pseudo-noise code from one of the two frequency tables created as described above, outputs frequency information read at each frequency hopping cycle as a spread code, and supplies a pseudo-noise code. Are alternately switched. Further, since the spreading code is output from one of the two frequency tables, the other unused frequency table can be rewritten with new frequency information.

According to the present invention, there is provided a first aspect in which one of the address information and the switching timing information created by the information creating means and the address information and the switching timing information input from the outside is selected and supplied to the frequency information generating means. A second switch for transmitting the address information and the switching timing information created by the information creating means to the outside, so that each of the wireless devices performs wireless transmission using frequency hopping as a spread spectrum modulation method. It can be provided in each of the master station and the slave station.

[0014]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of a spread code generator according to the present invention. The spread code generating apparatus according to this embodiment includes an M-sequence code that generates an M-sequence pseudo-noise code for each frequency hopping cycle using a clock generator for frequency hopping 1 and a clock from the clock generator for frequency hopping A generator 2, an amplifier 3 for amplifying thermal noise, an A / D converter 5 for converting an analog signal output from the amplifier 3 into a digital signal by a clock from a sampling clock generator 4, and an A / D converter 5
The address information generator 6 converts the output binary noise code into the address information necessary for creating the frequency table and the timing information necessary for switching the frequency table, and the address information and the timing information are input. It comprises a buffer 7, a first frequency table 9 and a second frequency table 10 created based on the frequency information generator 8 and output information of the buffer 7, and switches 11 to 15.

The frequency information generator 8 is constituted by a memory in which a plurality of pieces of frequency information are stored in advance. Each of the frequency tables 9 and 10 is composed of a memory in which frequency information is written to and read from an externally designated address. The switches 11 to 15 are switch circuits that are controlled to be switched by a switching signal from a switching signal generator (not shown) to which switching timing information to be described later is input. The switches 11, 12, 14, and 15 are configured to switch in conjunction with each other. ing.

Next, the operation of this embodiment will be described. In this embodiment, generation of frequency tables 9 and 10 and output of a spread code are performed. First, the operation of creating the frequency tables 9 and 10 will be described. Thermal noise existing in the natural world is amplified by the amplifier 3 and input to the A / D converter 5 as an analog signal. A / D converter 5
Performs quantization on the input analog signal based on the sampling clock input from the sampling clock generator 4 to generate a noise code which is a binary digital signal.

The noise code is supplied to an address information generator 6 and converted into address information necessary for creating a frequency table to be described later and switching timing information necessary for switching the frequency table. The data is supplied to the buffer 7 through the buffer 7. The buffer 7 supplies the input address information to the frequency information generator 8 as an address signal. As a result, the addresses are designated in a random order from the frequency information generator 8 in accordance with the noise code due to the thermal noise, and the frequency information is sequentially read from the designated address.

The buffer 7 is configured so that address information and timing information are inputted from the outside via the switch 12, and the inputted address information and timing information are outputted to the outside via the switch 13. You can output it.

The frequency information output from the frequency information generator 8 is input to one of the first frequency table 9 and the second frequency table 10 by the switch 14. The frequency tables 9 and 10 sequentially write the frequency information from the frequency information generator 8 input via the switch 14 to the addresses in order. Further, the frequency information output from the frequency table frequency information generation unit 8 by switching the switch 14 based on the switching timing information is alternately input to the first frequency table 9 and the second frequency table 10.

As a result, the frequency information generator 8 outputs F1,
Five frequency information of F2, F3, F4 and F5 are prepared, and when the switch 14 is connected to the frequency table 9, for example, F2, F5, F1, F4,
Assuming that the frequency information is read from the frequency information generator 8 in the order of F3, the frequency table 9 stores F2, F5, F1, F1,
4. A first frequency table in which F3 is written is created.

Similarly, the switch 14 sets the frequency table 1
When connected to the 0 side, for example, F3, F1, F5,
Assuming that the frequency information is read from the frequency information generator 8 in the order of F2 and F4, the frequency table 10 stores F3, F1,.
F5, F2, and F4 are created as a second frequency table in which are written. These frequency tables 9 and 10
Is a table in which frequency information read out in an order according to a noise code due to thermal noise is stored in association with a sequential address, and thus has much higher randomness than in the related art.

Next, the output operation of the spread code will be described with reference to the time chart of FIG. FIG. 3A generated by the clock generator 1 for frequency hopping
Is supplied to the M-sequence code generator 2 to generate an M-sequence pseudo-noise code for each frequency hopping cycle, as schematically shown in FIG. 3B. This M-sequence pseudo-noise code is input to one of the frequency tables 9 and 10 by the switch 11 as a read address.

Since the frequency tables 9 and 10 are prepared in advance as described above and stored therein, the read addresses (M-sequence pseudo-noise) input from the M-sequence code generator 2 via the switch 11 are stored. ), The storage frequency information is read out at the frequency hopping cycle.

Therefore, the switch 11 is added to the frequency table 9.
From the M-sequence code generator 2 via the
When a sequence pseudo noise code) is input, the read address is “1”, as schematically shown in FIG.
"2", "5", "3",. . . , In the order of the frequency hopping period, the frequency information “F2”, “F5”, “F3” from the frequency table 9 shown in FIG. ”,“ F
1 ",. . . In the order of the first frequency pattern.

Similarly, the switch 1 is added to the frequency table 10.
When a read address (M-sequence pseudo-noise code) is input from M-sequence code generator 2 through
From the frequency table 10 shown in (B), FIG.
As schematically shown in FIG.
1, "F4", "F5",. . . In the order of the second frequency pattern. The frequency information read from the frequency tables 9 and 10 is output via the switch 15 as a spread code. In this way, different spreading codes can be output for the same M-sequence noise code address.

Therefore, during a certain period T1, the switch 11
And 15 are connected to the frequency table 9 side, so that the spread code of the first frequency pattern schematically shown in FIG.
x switches switches 11 and 15 in frequency table 1
When the connection is switched to the 0 side, in the period T2 after the time tx,
The spread code of the second frequency pattern schematically shown in FIG. 3D can be switched and output for each frequency hopping cycle.

If the number of frequency tables is one as in the prior art, the same pattern is repeatedly output for each cycle of the M sequence. In the present embodiment in which the frequency tables 9 and 10 are switched and used, A spreading code (frequency information) that is more random than the period can be output. Furthermore, by rewriting the frequency information of the frequency table 9 or 10 that is not used during the non-use period, it is possible to generate a spreading code (frequency information) with even higher randomness.

Next, a second embodiment of the present invention will be described. FIG. 4 shows a second example of the spread code generator according to the present invention.
FIG. 2 is a block diagram of the embodiment. In this embodiment,
In the configuration in which the master station A and the slave station B of the wireless device are provided with the spreading code generators shown in FIG. 1 respectively, the same components as those in FIG. The constituent parts are given the suffix a, and the constituent parts of the slave station B are given the suffix b. In addition, although it is possible that there are a plurality of slave stations B,
Here, only one station is shown for convenience.

In FIG. 4, it is assumed that the master station A and the slave station B use the first frequency tables 9a and 9b having the same frequency table contents to perform wireless transmission using frequency hopping. Therefore, as shown in FIG.
The switches 11a and 15a are connected to the frequency table 9a, and the switches 11b and 15b are connected to the frequency table 9b. The switches 14a and 14b are connected to the unused frequency tables 10a and 10b. The frequency information generating units 8a and 8b store frequency information groups having the same contents in advance.

Here, in the main station A, the thermal noise is amplified by the amplifier 3a and taken in as an analog signal, and is quantized in the A / D converter 5a using the sampling clock output from the sampling clock generator 4a. Then, the analog thermal noise signal from the amplifier 3a is converted into a binary noise code. This noise code is converted by the address information generator 6a into address information necessary for creating a frequency table and switching timing information necessary for switching the frequency table, and then the switch 1
The data is input to the buffer 7a via 2a.

The address information and the switching timing information extracted from the buffer 7a are input to a frequency information generating section 8a, and the frequency information is sequentially read from designated addresses in a random order according to a noise code due to thermal noise. The frequency information output from the frequency information generator 8a is input to the second frequency table 10a by the switch 14a, where it is written in order and written in the frequency table 10a.
a is created. At the same time, the address information and the switching timing information extracted from the buffer 7a are wirelessly transmitted to the slave station B via the switch 13a.

The slave station B receives the address information and the switching timing information, and sends it to the buffer 7 via the switch 12b.
Input to b. The reception address information and the switching timing information extracted from the buffer 7b are input to the frequency information generator 8b, and the frequency information is sequentially read out from the designated addresses in a random order according to a noise code due to thermal noise. As a result, the frequency information is extracted from the frequency information generator 8b in the same pattern as that output from the frequency information generator 8a of the main station A, and the switch 14b
Is input to the second frequency table 10b, and is written here in order, so that the frequency table 10a
A frequency table 10b having the same contents as the above is created.

Thereafter, the switching timing information output from the buffer 7a and the buffer
b, the switches 11a, 14a, 15a, 11b, 14b, and 1 are generated by a switching signal generated by a switching signal generator (not shown) based on the switching timing information input to b.
5b are interlocked and switched. Thus, after the switching time, the frequency tables 10a and 1
By using 0b, wireless transmission using frequency hopping in which transmission and reception frequencies match is performed. At this time, the same frequency tables 9a and 9b are newly created in the master station A and the slave station B in the same manner as described above.

By repeating the above, the frequency tables 9a and 9b, 10a and 10b can be rewritten by the control of the master station A without interrupting the communication halfway, and the frequency tables 9a and 9b, 10a and 10b Can be switched, wireless transmission between the master station A and the slave station B using frequency hopping based on a spreading code that is more random than the cycle of the M sequence can be performed.

The present invention is not limited to the above embodiment. For example, it is possible to use other noises existing in the natural world other than thermal noise, and it is also possible to use known noises other than the M-sequence code. It is also possible to use pseudo noise (PN).

[0037]

As described above, according to the present invention,
Two frequency tables are created with frequency information generated in a random order based on address information generated from noise existing in the natural world, and frequency information read out from one of these two frequency tables for each frequency hopping period is spread. A conventional spread code generator that outputs frequency information as a code and alternately switches a frequency table for supplying a pseudo-noise code based on switching timing information, so that frequency information is output repeatedly for each cycle of the M-sequence pseudo-noise code. It is possible to generate a spreading code with high randomness as compared with a device.

According to the present invention, the frequency table for outputting the spread code (frequency information) by supplying the pseudo noise code is alternately switched based on the switching timing information, and the frequency table which is not used is switched. Is rewritten with new frequency information, so that the frequency table can be rewritten without interrupting communication.

Further, according to the present invention, one of the address information and the switching timing information generated internally and the address information and the switching timing information input from the outside are selected and supplied to the frequency information generating means. And a second switch for transmitting internally generated address information and switching timing information to the outside, so that each of the wireless devices performs wireless transmission using frequency hopping as a spread spectrum modulation method. The present invention can be provided for each of the master station and the slave stations, and more reliable wireless transmission using frequency hopping can be performed.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of a frequency table in FIG. 1;

FIG. 3 is a time chart for explaining the operation of FIG. 1;

FIG. 4 is a block diagram of a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a block diagram of an example of a conventional device and a frequency table used therein.

FIG. 6 is a time chart for explaining the operation of FIG. 5;

[Explanation of symbols]

1, 1a, 1b Frequency hopping clock generator 2, 2a, 2b M-sequence code generator 3, 3a, 3b Amplifier 4, 4a, 4b Sampling clock generator 5, 5a, 5b A / D converter 6, 6a 6b Address information generator 7, 7a, 7b buffer 8, 8a, 8b Frequency information generator 9, 9a, 9b First frequency table 10, 10a, 10b Second frequency table 11, 11a, 11b, 12, 12a, 12b, 13,
13a, 13b, 14, 14a, 14b, 15, 15
a, 15b Switch A Master station B Slave station

Claims (4)

[Claims] 1. A pseudo-noise code generating means for generating a pseudo-noise code for each frequency hopping cycle; a noise code generating means for generating a binary noise code from noise existing in nature; Information creating means for creating address information and switching timing information for creating a frequency table based on the generated noise code; and frequency information generating for generating frequency information based on the address information and switching timing information created by the information creating means. Means, when the frequency information generated by the frequency information generating means is input, the frequency information is written in a sequential address, and the pseudo noise code generated by the pseudo noise code generating means is input as an address signal. The first and second reading of the written frequency information at each frequency hopping cycle. A second frequency table; supplying the pseudo-noise code to one of the first and second frequency tables to output frequency information read out for each frequency hopping cycle as a spread code; In the other frequency table, the frequency information generated by the frequency information generating means is written into sequential addresses, and the frequency table for supplying the pseudo-noise code and the frequency table for writing the frequency information are stored in the switching timing information. And a switching control means for switching alternately based on the spread code. 2. A first switch for selecting one of the address information and the switching timing information created by the information creating means and the address information and the switching timing information input from the outside and supplying the selected information to the frequency information generating means. 2. The spread code generating apparatus according to claim 1, further comprising: a second switch for transmitting the address information and the switching timing information created by the information creating means to the outside. 3. A spread code generator provided in each of a master station and a slave station of a wireless device that performs wireless transmission using frequency hopping as a spread spectrum modulation method, wherein the first switch in the master station is The address information and switching timing information created by the information creating means are selected and supplied to the frequency information generating means, and the second switch transmits the address information and switching timing information created by the information creating means to outside. And the first switch in the slave station is connected so as to select the address information and the switching timing information input from outside and to supply them to the frequency information generating means. The spread code generator according to claim 2, wherein 4. The noise code generating means includes an amplifier for amplifying thermal noise, a sampling clock generator for generating a sampling clock, and converting an output signal of the amplifier into a binary noise code based on the sampling clock. The spread code generator according to any one of claims 1 to 3, further comprising an A / D converter.