JPH1022876A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spread spectrum radio communication system of frequency hopping system, with which the improvement of transfer rate or the improvement of secrecy is enabled. SOLUTION: When performing frequency hopping, communication time (residence time) utilizing one frequency can be changed. A user can arbitrarily set the changing method through a dial part 39. At the time of image information or the like having numerous data, the residence time is prolonged and at the time of audio information or the like having little data, the residence time is reduced. When secrecy is found, the residence time is reduced and when secrecy is fount not, the residence time can be prolonged as well. Such setting of residence time can be automatically set not only by the manual operation of user but also by discriminating the class of data as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system for performing bidirectional communication between communication devices while switching frequencies according to a predetermined hopping pattern by a frequency hopping method.

[0002]

2. Description of the Related Art Conventionally, in a wireless communication system using the above spread spectrum communication system, effective use of frequency,
In addition, there is a communication system based on a frequency hopping system (hereinafter, referred to as an FH system) used to enhance confidentiality. In the FH method, a carrier is spread by hopping according to a rule predetermined by a spreading code sequence. A conventional two-way communication system using a spread spectrum communication system based on the FH system is shown in FIG.
It was configured like 2.

[0003] First, the operation of the communication device when transmitting data will be described. According to the spreading code sequence output from the spreading code sequence generator 5, a signal of a random frequency is output from the frequency synthesizer 6. Transmission data input terminal 20
Receives a primary modulation signal. Transmission data input terminal 2
The output frequency of the primary modulation signal supplied to 0 is determined by the up-converter 3 based on the output from the frequency synthesizer 6. The transmission data frequency-converted by the up-converter 3 is amplified by the amplifier 8, and then transmitted and output from the antenna 11 via the duplexer 10.

Next, the operation of the communication device in the case of receiving will be described. The signal received by the antenna 11 is
After being separated from the transmission wave by the amplifier 9 and amplified by the amplifier 9, the signal is input to the down converter 7, the frequency is converted by the down converter 7 based on the signal designating the frequency from the frequency synthesizer 6, and demodulated by the demodulator 12. This is received data. The received data is output to a data operation circuit (not shown) and also to the synchronization circuit 4.

[0005] The synchronization circuit 4 detects the phase of the hopping frequency from the received signal, and outputs a synchronization signal from the synchronization circuit 4 to the spread code sequence generator 5. Spreading code sequence generator 5
Outputs a spread code sequence according to the input synchronization signal. The spread code sequence output from the spread code sequence generator 5 is supplied to a frequency synthesizer 6. The frequency synthesizer 6 generates a random frequency output according to the input spread code sequence. Down converter 7 multiplies the received signal by the output from frequency synthesizer 6 to despread the received signal.

[0006] The despread signal despread in the down converter 7 is demodulated in a demodulator 12 to obtain received data in the demodulator 12, and the demodulated received data is output from a received data output terminal 21. To perform two-way communication with such a transceiver, these transmitters and receivers operate simultaneously.

The random frequency means that a spread code output from the spread code generator 5 every time a synchronization signal is input changes randomly, and the sequence of the spread code (frequency hopping pattern) ) Is transmitted and received by sharing a set of communication devices with each other.

[0008]

However, the above F
In a wireless communication system using the H system, a time period during which the frequency generated by the frequency synthesizer is stabilized immediately after hopping (hereinafter referred to as “occupation time”) is required.
Here, in the wireless communication using the FH method, an upper limit is set for the communication time on the same frequency in order to keep the communication confidential and to increase the number of channels. And hopping is performed for each residence time T ′. As shown in FIG. 13, when the frequency hops from one frequency band (for example, f1) to another frequency band (for example, f2), an unstable time (t) of the frequency is the occupation time. Normal communication cannot be performed during this occupation time, and there is a waiting time in the entire system until the frequency is stabilized. As a result, the transmission speed is reduced in principle as compared with the communication in which the carrier frequency is normally used for the amateur radio or the like.

On the other hand, considering the confidentiality of communication information, it is preferable to make the frequency hop more frequently than to keep the carrier frequency constant. The present invention has been made to solve the above-described problems, and has as its object to provide a wireless communication system capable of improving either a transfer rate or confidentiality.

[0010]

Means for Solving the Problems and Effects of the Invention In order to solve the above problems, the invention according to claim 1 is directed to a wireless communication system for performing bidirectional communication while switching frequencies according to a predetermined hopping pattern by a frequency hopping method. A dwell time control unit that changes the length of time (hereinafter referred to as dwell time) for continuing to use the frequency switched according to the predetermined hopping pattern and performs communication based on the changed dwell time. I do.

In such a wireless communication system, the length of the residence time can be changed by the residence time control means, and communication is performed by the FH method using the residence time changed by the residence time control means. Here, the length of the staying time is set to be equal to or less than the upper limit, since the upper limit of the communication time on the same frequency is set, for example, for confidentiality of communication and multi-channel. The closer the changed residence time is to this upper limit, the less the number of times that the frequency hops per time is reduced, so that the total length of the occupation time is reduced and the transfer rate is increased. On the other hand, the shorter the changed residence time, the greater the number of times that the frequency hops per time. Therefore, the confidentiality of the information is improved.

According to such a wireless communication system, if the residence time is lengthened, the occupation time during frequency hopping can be reduced, thereby improving the transfer rate.
When the residence time is shortened, an effect is obtained that the confidentiality can be improved by increasing the number of frequency hoppings.

According to a second aspect of the present invention, there is provided the wireless communication system according to the first aspect, further comprising a dwell time input unit capable of inputting an arbitrary value as the length of the dwell time, wherein the dwell time control unit comprises: The residence time is changed to an arbitrary value input by the residence time input means.

In such a wireless communication system, the user can input an arbitrary value as the length of the staying time according to, for example, the type of information to be transmitted. For example, if the information to be transmitted can be announced, the transfer time can be improved by setting a longer residence time, and if the information to be transmitted is highly confidential. The confidentiality can be improved by setting a short residence time.

According to such a wireless communication system, it is possible to improve either the transfer rate or the secrecy by changing the residence time according to the needs of the user. According to a third aspect of the present invention, in the wireless communication system according to the first or second aspect, the dwell time control means reduces a length of the dwell time when the communication information is voice information.
When the communication information is non-voice information, the communication information is changed so as to be longer.

In such a wireless communication system, the residence time is long when non-voice information is communicated, and the residence time is short when voice information is communicated. This is because, in the case of non-voice information, the amount of information is relatively large, so it is often necessary to increase the transfer rate rather than confidentiality. Focus on confidentiality rather than increasing For example, it may be configured to sequentially determine whether the communication information is non-voice information or voice information and change the residence time sequentially, but the following configuration may be used. That is, whether the communication device on the transmission side transmits only image information which is non-voice information like a dedicated facsimile machine or only the audio information like a telephone is determined by the communication on the transmission side. Machine-specific signals (eg ID
The communication device on the receiving side may be configured to recognize the communication device on the basis of the signal, and change the staying time of the communication device on the receiving side by the staying time changing unit according to the result of the recognition.

According to such a wireless communication system, there is an effect that either the transfer rate or the confidentiality can be improved by changing the residence time to an appropriate residence time according to the type of information. According to a fourth aspect of the present invention, in the wireless communication system according to any one of the first to third aspects, when the communication information includes the dwell time information, the dwell time control unit determines the dwell time. The value is changed so as to be a value according to the stay time information.

[0018] In such a wireless communication system, for example, the transmitting-end communication device may be configured to add the residence time information and transmit the transmission information each time the transmission information is transmitted. In this case, the length of the staying time may be determined according to the transmission information, such as long for non-voice information such as image information and short for voice information.

According to such a wireless communication system, since the staying time is changed according to the staying time information included in the communication information, two-way communication is performed with the staying time having a length corresponding to the type of the communication information. The effect is obtained that either the transfer rate or the confidentiality can be improved.

According to a fifth aspect of the present invention, there is provided the wireless communication system according to any one of the first to fourth aspects, wherein the residence time control means is configured to transmit the residence time when communicating by a packet switching system. Among them, the residence time is changed so that the communicable time becomes an integral multiple of the packet length.

In such a wireless communication system, communication is performed by a packet switching system. In the packet switching system, communication information is temporarily stored in a buffer memory and then divided into blocks of a fixed length (called packets).
To the other party. In this case, if the communicable time of the staying time (the time excluding the occupation time of the staying time) is not an integral multiple of the packet length, the difference between the communicable time and the integral multiple of the packet length becomes the remaining time. As a result, information cannot be sent during this extra time, and the transfer rate cannot be sufficiently increased. On the other hand, if the communicable time is an integral multiple of the packet length, such extra time does not occur, so that transmission can be performed efficiently and the transfer rate increases as a result.

According to such a wireless communication system, there is an effect that the transfer rate can be increased when performing packet communication. The invention according to claim 6 is the wireless communication system according to any one of claims 1 to 5, further comprising a change pattern storage unit that stores a change pattern of the stay time, wherein the stay time control unit is configured to perform the change of the stay time. The residence time is changed according to the residence time change pattern stored in the pattern storage means.

In such a wireless communication system, the residence time of a certain frequency is determined according to the residence time change pattern. Here, in the change pattern, for example, the residence time may be determined for each frequency to be switched, or it may be determined whether to maintain or change the frequency at that time every fixed time. In this case, even if a third party attempts to intercept the communication information, not only the frequency is switched but also the dwell time is switched, so that it is extremely difficult to intercept and the effect of improving confidentiality is obtained.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. Note that the embodiment of the present invention
It is needless to say that the present invention is not limited to the following embodiments, and can take various forms within the technical scope of the present invention.

FIG. 1 is a block diagram showing a circuit configuration of a communication device according to this embodiment, and FIG. 2 is a flowchart showing a procedure of wireless communication according to this embodiment. Since the communication devices 1a and 1b have substantially the same configuration, the communication device 1 will be described below. However, when it is necessary to distinguish between the communication devices 1a and 1b, the reference numeral representing the configuration of the communication device 1a is appended with a, and the reference numeral representing the configuration of the communication device 1b is appended with b.

The communication device 1 of this embodiment mainly includes a synchronization unit 25, a spread code sequence generator 26, a communication unit 50, and a control unit 3.
8 is provided. The synchronizing unit 25 is a circuit for synchronizing with a communication partner, and outputs a synchronizing signal of a constant frequency to the control unit 3.
8.

The spread code sequence generator 26 reads a command signal output from the control unit 38 in response to the synchronization signal,
If it is a frequency hop command signal for commanding frequency hopping, a spread code in the next column of the hopping table 35 (see Table 1 below), which is a spread code sequence, is output to the frequency synthesizer 28.

[0028]

[Table 1]

In the communication section 50, when the spreading code is given from the spreading code sequence generator 26, the frequency synthesizer 28 oscillates an oscillating frequency corresponding to the spreading code. The signal of the oscillation frequency (f _{N ′} ) from the frequency synthesizer 28 is mixed with the signal (frequency f _IF ) from the data redundancy device 36 by the up-converter 22 and output as a transmission signal of the frequency f _N , and the amplifier 30 And transmitted from the antenna 33 via the duplexer 32. On the other hand, the signal of the frequency f _N received by the antenna 33 is transmitted through the duplexer 32 to the amplifier 31.
The signal is amplified by the down converter 29 and mixed with the signal of the oscillation frequency (f _{N ′} ) from the frequency synthesizer 28 by the down converter 29 to generate an output signal (frequency f _IF ), and outputs this signal to the demodulator 34.

The control unit 38 operates in response to the synchronization signal, and controls the reception data output terminal 21 and the down converter 29
The input side is connected to the demodulator 34 connected between the data and the data redundant unit 36 via the primary modulator 37. The data redundancy device 36 is connected between the transmission data input terminal 20 and the up-converter 22, and makes the transmission data input from the transmission data input terminal 20 redundant with the data from the control unit 38.

The control section 38 includes a well-known CPU and the like, and includes a dial section 39, a storage section 40, a timer section 41 and the like. The dial unit 39 corresponds to the stay time input unit of the present invention, and can set the stay time at the time of transmission to an arbitrary value by turning the dial knob by the user. The storage unit 40 includes, for example, a known RAM, ROM, or the like. The storage unit 40 stores a predetermined occupation time t as a time at which the frequency becomes unstable when the frequency hops from one frequency band to another frequency band. In addition, the staying time changed by the dial unit 39 is sequentially stored.

Next, two-way communication between the two communication devices 1a and 1b will be described with reference to the flowcharts of FIGS.
Explanation will be made based on the time chart of FIG. As shown in FIG. 4, the format of the transmission data is such that the residence time information is added to the header and the transmission information is added after that. In the flowcharts of FIGS. 2A and 2B, the processing in which the last two digits of the step numbers coincide with each other indicates that the processing is performed substantially simultaneously. Further, the description will be made on the assumption that the two communication devices 1a and 1b are synchronized.

First, the processing of the communication device 1a will be described with reference to FIG.
Description will be made based on (a). When the processing is started, the control unit 38a transmits the frequency hop signal to the spreading code sequence generator 26.
a to generate a spreading code of the next column and hop the frequency (S101). Then, the spreading code sequence generator 2
6a gives the up-converter 22 the spreading code of the next row in the spreading code row.

Subsequently, the control unit 38a determines whether a predetermined occupation time t has elapsed (S102). That is, a predetermined occupation time t is read from the storage unit 40a, and the occupation time t is set in the timer unit 41a to start the countdown. The predetermined occupation time t is determined based on whether or not the count of the timer unit 41a has become zero. It is determined whether or not it has elapsed.
If the occupation time t has not elapsed (NO in S102),
The process of S102 is performed again. On the other hand, if the occupation time t has elapsed (YES in S102), it is considered that the frequency has been stabilized at the hopped frequency, and subsequently the dwell time T set by the dial unit 39a is read from the storage unit 40a, and stored in the timer unit 41a. It is set (S103). Here, when the residence time T set by the dial unit 39a is set in the timer unit 41a, the timer unit 41a starts counting down the time obtained by subtracting the occupation time t from the residence time T.

Subsequently, the control section 38a creates and transmits transmission data based on the staying time T (S104). Specifically, transmission data having a length obtained by subtracting the occupation time t from the dwell time T is created based on the input data from the transmission data input terminal 20a, and the dwell time information (to the dial unit 39a) is generated together with the transmission data. Is output to the primary modulator 37a, and the primary modulator 37a modulates the modulated data to add the dwell time information to the header of the transmission data by the data redundancy unit 36a. The signal is transmitted from the antenna 33a to the communication device 1b via the device 32a. Whether or not the transmission has been completed is determined based on whether or not the count of the timer section 41a has become zero.

After the transmission is completed, the control unit 38a outputs a frequency hop signal to the spread code sequence generator 26a, generates a spread code of the next sequence, and hops the frequency (S1).
07). Then, it is determined whether or not the predetermined occupation time t has elapsed (S108). If not (NO in S108), the process returns to S108. On the other hand, the predetermined occupation time t
Has elapsed (YES in S108), it is regarded as being stable at the frequency after the hop, and the data is subsequently received from the communication device 1b (S110 to S112).

That is, when the signal received from the antenna 33a is input via the duplexer 32a, the amplifier 31a, the downconverter 29a, and the demodulator 34a, the control unit 38a reads the residence time information attached to the header (S110). ,
The dwell time Tb represented in the dwell time information, ie, the communication device 1
The residence time Tb set by the dial unit 39b of b is set in the timer unit 41a (S111). Here, when the dwell time Tb set by the dial unit 39b of the communication device 1b is set in the timer unit 41a, the timer unit 41a subtracts the occupation time t and the time required for receiving the header from the dwell time Tb. Start the countdown. Subsequently, the remaining data is received (S112). Whether or not the reception has been completed is determined by whether or not the count of the timer section 41a has become zero. Then, after the reception is completed, that is, after the count of the timer unit 41a becomes zero, S10 is again executed.
The following processing is performed.

Next, the processing of the communication device 1b will be described. Note that the processing of the communication device 1b is substantially the same as that of the communication device 1a except that the order of transmission and reception is different, so that the description will be made somewhat simplified. First, when the processing is started, the control unit 38
b outputs a frequency hop signal to the spread code sequence generator 26b at the same timing as S101 of the communication device 1a, and hops to the same frequency as the communication device 1a (S201). Subsequently, it is determined whether or not a predetermined occupation time t has elapsed at the same timing as S102 of the communication device 1a (S202). Then, if the predetermined occupation time t has elapsed (Y in S202)
ES), and subsequently receives data from the communication device 1a (S)
204 to S206).

That is, the control unit 38b reads out the staying time information attached to the header (S204), and the staying time Ta indicated in the staying time information, that is, the staying time Ta set by the dial unit 39a of the communication device 1a. Is set in the timer section 41b (S205). Here, when the residence time Ta is set in the timer section 41b, the timer section 41b sets the residence time T
The countdown of the time obtained by subtracting the occupation time t from a is started. Subsequently, the remaining data is received (S20).
6).

After the reception is completed, the control unit 38b outputs a frequency hop signal to the spread code sequence generator 26b, and hops the frequency at the same timing as S107 of the communication device 1a (S207). Then, after the predetermined occupation time t has elapsed (YES in S208), the data is transmitted to the communication device 1a (S209 to S210).

That is, the control unit 38b is controlled by the dial unit 39b.
Is set in the timer section 41b (S209). Here, the residence time Tb is determined by the timer unit 4
When it is set to 1b, the timer unit 41b starts counting down the time obtained by subtracting the occupation time t from the residence time Tb.

Subsequently, transmission data is created based on the residence time Tb and transmitted (S210). After the transmission is completed, that is, after the count of the timer unit 41b becomes zero, the process returns to S201 again. FIG. 3 shows a time chart of the above two-way communication between the communication devices 1a and 1b. As is clear from the time chart, the communication device 1a transmits at the hop frequency f1 with the dwell time Ta, the communication device 1b performs reception, and the communication device 1a receives the hop frequency f2 with the dwell time Tb. , The communication device 1b performs transmission and the residence time Ta at the hopped frequency f3.
The communication device 1a performs transmission and the communication device 1b performs reception. In this way, the transmitting side of the communication device takes the initiative and the residence time is determined. At this time, the residence time Ta (or T
b) is a value including the occupation time t. For this reason,
The length of the transmission or reception time slot is the residence time Ta
(Or Tb) minus the occupation time t.

Here, the control section 38 corresponds to the residence time control means of the present invention, and the processing of S103, S104, and S11
0, S111, S204, S205, S2
09 and S210 correspond to the processing of the residence time control means. According to the above-described embodiment, if the user increases the residence time, the ratio of the occupation time during frequency hopping to the residence time can be reduced, thereby improving the transfer rate. . On the other hand, if the user shortens the residence time, the confidentiality can be improved by increasing the number of frequency hoppings.

In the above embodiment, "switching of transmission / reception" is performed instead of S107 and S108 in the processing of the communication device 1a, and S20 in the processing of the communication device 1b.
7. Instead of S208, “switching of reception and transmission” may be performed (see FIG. 5). In this case, the communication device 1a
Hop at 101 and transmit at that frequency (S102
To S104), and then continuously receive (S110 to S1)
12), while the communication device 1b performs reception (S202 to S206) at the same frequency, and then continuously transmits (S202).
209 to S210). As a result, the obtained time chart is as shown in FIG. That is, the frequency hops for each unit of transmission and reception. In this case, the same effect as in the above embodiment can be obtained.

In FIG. 2 of the above embodiment, in S103 of the communication device 1a, the dwell time T _VO if the input data from the transmission data input terminal 20a is voice data, and the dwell time T if the input data is facsimile data. _FA (T _FA > T _VO , where T _FA does not exceed the upper limit of the communication time at the same frequency in wireless communication using the FH method)
It may be set to a. Specifically, it is determined that there facsimile data if it contains e.g. CNG signal in the input data and the residence time T _FA, to the residence time determined to be voice data must contain the CNG signal T _VO
It may be. Alternatively, when the communication device 1a is a shared device of a telephone and a facsimile, the communication time may be set to the residence time T _VO, and may be set to the residence time T _FA only when a facsimile start button is pressed and transmitted.

[0046] for longer than the residence time T _VO of the audio data the residence time T _FA of such a facsimile data,
In the case of facsimile data, the amount of information is relatively large, so it is often necessary to increase the transfer rate rather than confidentiality.On the other hand, in the case of voice data, the amount of information is relatively small, so it is better to increase the transfer rate. Rather, they focus on the fact that confidentiality is often important. In this case, an effect is obtained in which either the transfer rate or the confidentiality can be improved by changing the residence time to an appropriate residence time according to the type of transmission / reception data.

Further, in FIG. 2 of the above embodiment, in S103 of the communication device 1a, the dwell time is set in the timer section 41a based on its own model (facsimile dedicated machine or telephone). _FA , if the telephone, the residence time T _VO ), and in S104, the terminal may transmit its own ID signal as the residence time information. At this time, in S204 of the communication device 1b, the model of the partner is determined based on the received ID signal, and in S205, either the staying time T _FA or the staying time T _VO is set in the timer unit 41b. In this case, an effect is obtained in which either the transfer rate or the confidentiality can be improved by changing the residence time to an appropriate residence time according to the model.

Further, in step S103, every time a new two-way communication is started, the control unit 38a sequentially reads out the staying time from a table in which the staying times are randomly arranged, and uses the read-out time in the current two-way communication. May be set as the staying time. In this case, the staying time used in the previous two-way communication and the staying time used in the current two-way communication are changed. Alternatively, the control unit 38a may be configured to change the staying time in S103 using, for example, a hopping table in which a staying time change table is described as shown in Table 2 below. In this case, each time the frequency switches, the residence time also switches. In these cases, even if a third party attempts to intercept the communication information, not only the frequency is switched but also the residence time is switched, so that it is extremely difficult to intercept and the effect of improving confidentiality is obtained.

[0049]

[Table 2]

Next, a second embodiment will be described. Second
The wireless communication system according to the second embodiment has the same configuration as that of the first embodiment, and a description thereof will be omitted. However, in a predetermined area of the storage unit 40a of the communication device 1a, a temporary residence time T _H (residence time of a certain length) is stored, and a residence time change pattern (for example, see Table 3 below) is stored. Have been.
The storage section 40b of the communication device 1b also stores the temporary staying time _TH and the change pattern of the staying time (the same pattern as that of the communication device 1a or a different pattern).

[0051]

[Table 3]

Next, two-way communication between the two communication devices 1a and 1b will be described with reference to the flowcharts of FIGS. 7A and 7B and the time chart of FIG. As shown in FIG. 9, the format of the transmission data is such that a hop information flag as dwell time information is added after the transmission information. The description will be given on the assumption that the two communication devices 1a and 1b are synchronized. In addition, the processing in which the last two digits of the step numbers in both flowcharts match indicates that they are performed substantially simultaneously.

First, the communication device 1a will be described. When the process is started, the control unit 38a outputs a frequency hop signal to the spread code sequence generator 26a to hop the frequency (S301). Then, the spreading code sequence generator 26a converts the spreading code of the next sequence in the spreading code sequence
Give to 2.

Subsequently, the control unit 38a determines whether a predetermined occupation time t has elapsed (S302). If the predetermined occupation time t has elapsed (YES in S302), it is considered that the hopped frequency is stable, and a hop information flag is created (S303). That is, the storage unit 40a
According to the residence time change pattern (see Table 3 above),
If the current hop information is “change”, the hop information flag is turned on, and if “maintain”, the hop information flag is set to off. Then, a temporary residence time T _H timer unit 41a
Set to. When the hop information corresponding to the number 1 is set in the current S303, the hop information corresponding to the number 2 is set in the next S303, and the change pattern returns to the number 1 again after the number k.

Subsequently, the control unit 38a determines the temporary residence time T
_The transmission data is created and transmitted based on _H (S30).
4). Specifically, based on input data from the transmission data input terminal 20a, to create transmission data of the temporary residence time T _H content length, outputs a hop information flag to the primary modulator 37a together with the transmission data These are modulated, and a hop information flag is added to the end of the transmission data by the data redundancy unit 36a.
a, communication device 1 from antenna 33a via duplexer 32a
b. It should be noted that whether the transmission has been completed is determined by the timer unit 4.
It is determined whether or not the count of 1a has become zero.

After the transmission is completed, the control unit 38a
The hop information flag set in step S03 is read (S30).
5). If the hop information flag is ON, a spreading code of the next sequence is generated according to the spreading code sequence to hop the frequency (S306), and after the occupation time t has elapsed (S307).
Then, the process proceeds to S309. On the other hand, if the hop information flag is off in S305, the process proceeds to S309 without updating the spreading code and without hopping the frequency.

In S309, control unit 38a sets communication device 1b
Receive data from The signal received from the antenna is transmitted to the duplexer 32a, the amplifier 31a,
9a, input via demodulator 34a. Subsequently, the hop information flag is read out, and it is determined whether the hop information flag is on or off (S310). If the hop information flag is ON in S310, the process proceeds to S301, in which a spreading code of the next sequence is generated according to the spreading code sequence to hop the frequency,
After that, the process from S302 is performed. On the other hand, if the hop information flag is off in S310, the processing from S303 is performed without updating the spreading code and without hopping the frequency.

Next, the processing of the communication device 1b will be described. Note that the processing of the communication device 1b is substantially the same as that of the communication device 1a except that the order of transmission and reception is different, so that the description will be made somewhat simplified. First, when the processing is started, the control unit 38
b outputs a frequency hop signal to the spread code sequence generator 26b at the same timing as S301 of the communication device 1a, and hops to the same frequency as the communication device 1a (S401). Subsequently, it is determined whether or not the predetermined occupation time t has elapsed at the same timing as S302 of the communication device 1a (S402). After the predetermined occupation time t has elapsed (YES in S402), the communication device 1a Is received (S404). Then, the hop information flag is read, and ON / OFF of the read hop information flag is determined (S405). S40
If the hop information flag is on at 5, the next sequence of spreading codes is generated according to the spreading code sequence to hop the frequency (S
406) After the occupation time t has elapsed (YE in S407).
S), and proceed to S408. On the other hand, if the hop information flag received in S405 is off, the process proceeds to S408 without updating the spreading code and hopping the frequency.

In S408, the control unit 38b creates a hop information flag. That is, the storage unit 40 of the communication device 1b
According to the staying time change pattern stored in b, if the current hop information is “change”, the hop information flag is set to on, and if the current hop information is “maintain”, the hop information flag is set to off.

[0060] Then, to create the transmission data based on the temporary residence time T _H, sends (S409). Then, after the transmission is completed, the hop information flag set in S408 is read (S410). If the hop information flag is ON in S410, the process proceeds to S401, in which a spreading code of the next column is generated according to the spreading code sequence, and the frequency is hopped.
The following processing is performed. On the other hand, if the hop information flag is off at S410, the process proceeds to S404 without updating the spreading code and without hopping the frequency.

FIG. 8 shows an example of a time chart of the two-way communication between the communication devices 1a and 1b. Here, the frequency f1
Assuming that the hop information of the residence time change pattern of the communication device 1a immediately after the hop is “maintained”, the communication device 1a
Sets the hop information flag to off in S303. And it transmitted the temporary residence time from the communication device 1a to the communication device 1b T _H at this frequency f1. After the transmission, the frequency f1 is maintained because the hop information flag in S303 is off.

Next, assuming that the hop information of the residence time change pattern of the communication device 1b is "change", the communication device 1b
b sets the hop information flag to ON in S408.
Then, transmitted in temporary residence time from the communication device 1b to the communication device 1a T _H at frequency f1. After the transmission, since the hop information flag in S408 is ON, the hop to the frequency f2 is performed.

As described above, the hop information flag is turned on / off in accordance with the residence time change pattern, whether to hop the frequency is determined in accordance with the hop information flag, and the actual length of the residence time is determined. According to the above-described embodiment, even if a third party attempts to intercept communication information, it is extremely difficult to intercept because not only the frequency is switched but also the residence time is switched, and the effect of improving confidentiality is obtained. Can be

As a modification of the second embodiment, the communication device 1
This embodiment may be applied to the case where communication is performed from a to the communication device 1b by the packet switching method. That is, the communication device 1a temporarily stores the transmission data in the buffer memory, and thereafter, makes the packet divided into blocks of a fixed length,
It may be configured to transmit to. In this case, the communication device 1a sets the temporary residence time T _H as the packet length L _PAC and stores it in the storage unit 40.
Stored in a. The control unit 38a, the actual residence communicable time of the time n times (time excluding the occupied time t) is the temporary residence time T _H (n is an integer), and, the actual residence time After setting so as not to exceed the upper limit value of the communication time at the same frequency in the wireless communication using the FH method, the change pattern is created as shown in Table 4 below and stored in the storage unit 40a.

[0065]

[Table 4]

Here, in the second embodiment, in the flowchart of FIG. 7, when the hop information flag is turned off in S305, the communication device 1a performs the reception processing of S309 and thereafter. Machine 1a is S305
In the case where the hop information flag is off in FIG.
The process proceeds to step S303, and the process after step S303 is performed (other steps are the same as those in the second embodiment).

As a result, according to this modification, a time chart as shown in FIG. 10 is obtained. That is, the communicable time (the time excluding the occupation time t) of the actual stay time is:
It is n times (4 times here) the packet length _LPAC . Here, if the communicable time is not n times the packet length _LPAC , as shown in FIG. 11 (b), extra time in which information cannot be transmitted occurs in the actual staying time, so that the transfer rate is not sufficient. Can not be raised. However, if the communicable time is n times the packet length _PAC , as shown in FIG. 11 (a), there is no extra time as described above, and the transfer rate can be sufficiently increased. Can be

When the total number of packets to be transmitted is m, it is desirable to determine the value of n so that m = n × p (p is an integer). When m and n do not satisfy the above relationship, as shown in FIG. 11C, a space corresponding to the packet length L _PAC is generated in the actual staying time when the last packet is transmitted. The rate cannot be raised sufficiently. On the other hand, when m and n satisfy the above relationship, such a vacancy does not occur, so that the transfer rate can be more sufficiently increased.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a communication device for realizing a wireless communication system of the present invention.

FIGS. 2A and 2B are flowcharts showing processing of two communication devices in the first embodiment, wherein FIG. 2A shows processing of one communication device and FIG. 2B shows processing of the other communication device.

FIG. 3 is a time chart of wireless communication in the first embodiment.

FIG. 4 is an explanatory diagram of a transmission data format in the first embodiment.

FIGS. 5A and 5B are flowcharts illustrating processing of two communication devices in a modification of the first embodiment, where FIG. 5A illustrates processing of one communication device and FIG. 5B illustrates processing of the other communication device.

FIG. 6 is a time chart of wireless communication in a modification of the first embodiment.

FIGS. 7A and 7B are flowcharts showing processing of two communication devices in the second embodiment, wherein FIG. 7A shows processing of one communication device and FIG. 7B shows processing of the other communication device.

FIG. 8 is a time chart of wireless communication in the second embodiment.

FIG. 9 is an explanatory diagram of a transmission data format in the second embodiment.

FIG. 10 is a time chart of wireless communication in a modification (packet communication) of the second embodiment.

FIG. 11 is an explanatory diagram illustrating a relationship between a residence time and a packet length.

FIG. 12 is a schematic block diagram of a communication device used in a conventional wireless communication system.

FIG. 13 is a graph showing a relationship between a carrier frequency and time in a conventional wireless communication system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Communication apparatus, 20 ... Transmission data input terminal, 21
... Reception data output terminal, 22 ... Up converter, 25 ... Synchronizing unit, 26 ... Spread code sequence generator, 28 ... Frequency synthesizer, 29 ... Down converter, 30, 31 ..Amplifier, 32 ... shared device, 33 ... antenna, 34 ... demodulator, 36 ...
Data redundancy device, 37 primary modulator, 38 control unit, 39 dial unit, 40 storage unit, 41
... Timer unit, 50 ... Communication unit

Claims (6)

[Claims] 1. A wireless communication system for performing two-way communication between communication apparatuses while switching frequencies according to a predetermined hopping pattern by a frequency hopping method, wherein a time for continuously using the frequency switched according to the predetermined hopping pattern Wireless communication system comprising: a stay time control unit that changes the length of the stay time and performs communication based on the changed stay time. 2. A dwell time input means capable of inputting an arbitrary value as a dwell time length, wherein the dwell time control means changes the dwell time to an arbitrary value input by the dwell time input means. The wireless communication system according to claim 1, wherein: 3. The dwelling time control means sets the length of the dwelling time to be shorter when the communication information is audio information.
3. The wireless communication system according to claim 1, wherein the communication information is changed to be longer when the communication information is non-voice information. 4. The communication device according to claim 1, wherein when the communication information includes the residence time information, the residence time control means changes the residence time to a value corresponding to the residence time information. The wireless communication system according to claim 3. 5. The communication device according to claim 1, wherein when the communication is performed by the packet switching system, the communication time is changed so that the communicable time of the communication time becomes an integral multiple of the packet length. The wireless communication system according to claim 1. 6. A change pattern storage means for storing a change pattern of the stay time, wherein the stay time control means changes the stay time according to the change pattern of the stay time stored in the change pattern storage means. The wireless communication system according to claim 1.