JPH1093533A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a system to flexibly cope with a change in communication circumstance such as a kind of communication data, the number of communication equipments and a frequency of communication by changing the number of hops of a hopping pattern. SOLUTION: The number of hops of a hopping pattern is changed depending on a change in a communication circumstance such as a kind of communication data, the number of communication equipments and frequency of communication in the communication control routine. Concretely in the case of communication of voice data (voice signal), the small number of (L sets) hops placing a high priority to real time performance is selected as shown in figure (a) and frequency hopping is conducted according to the hopping pattern of the hop number (L sets). Furthermore, in the case of communication of non-voice data (non-voice signal) for an equipment such as a computer, a facsimile equipment and a printer, the many hop numbers (M sets) placing high priority onto the reliability are selected as shown in figure (b) and the frequency hopping is conducted in the hopping pattern of the hop numbers (M sets).

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 In recent years, a spread spectrum wireless communication system that obtains communication data by despreading and demodulating a received signal while modulating and transmitting communication data after modulation has been developed. Attention has been focused on enabling low power density communications. In particular, when performing spread and despreading by frequency hopping in which the frequency is sequentially switched during transmission and reception by the spread spectrum method, the confidentiality of the signal becomes extremely high. Therefore, the spread spectrum wireless communication using the frequency hopping is applied. Systems are about to be widely adopted in various fields such as telephones and facsimile machines.

Conventionally, in a radio communication system of the above-mentioned method, the same hop table having hop frequency data indicating spreading and despreading patterns for a predetermined channel is provided in all communication devices, and the hopping pattern of this hop table is provided. Therefore, communication between the communication devices is performed while frequency hopping is performed at every fixed residence time.

That is, for example, when communication is performed from a master communication device to a specific slave communication device, first,
In the communication start process, a paging signal including ID data of the child device is formed by the parent device, and this paging signal is transmitted as a spread modulation signal while being frequency-hopped every fixed dwell time. At this time, the slave unit is made to stand by to receive a spread modulation signal of a predetermined frequency, and when a spread modulation signal from the master unit is captured, a frequency of a frequency according to a hopping pattern is determined for each residence time. Switching is performed so that the call signal from the base unit is despread and received. Then, after establishing synchronization between the master unit and the slave unit, the frequency hopping is repeatedly performed by the master unit and the slave unit, so that a communication process for continuously transmitting and receiving communication data is executed. I have.

[0005]

However, in a configuration in which frequency hopping is performed at a constant hop number (the number of channels) based on a hopping pattern and at a constant dwell time as in the above-described conventional technique, the type of communication data and the number of communication devices However, there is a problem that it is not possible to flexibly respond to changes in communication circumstances such as the frequency of communication.

That is, communication data transmitted and received in a wireless communication system is divided into two minutes: voice data for which real-time communication is desired by shortening the time required for acquisition and non-voice data for which highly reliable data transfer is desired. can do. Therefore, initially, for example, the system handles only voice data, so if the number of hops is set to a small number of hops giving priority to real-time processing to support voice data, communication data will be changed to non-voice When it becomes necessary to switch to data, or when a communication device for communicating with non-voice data is added, communication of non-voice data must be performed with a small number of hops having insufficient reliability. On the other hand, if the number of hops is set to a number that prioritizes reliability so as to correspond to non-voice data, communication with voice data requires a long time to acquire, so communication with low real-time properties must be performed. Become.

Further, if communication is performed in a fixed hopping pattern with a fixed number of hops and a fixed time, if only this hopping pattern is recognized, communication data can be received and its contents can be read. There is also a problem that it is relatively easy.

Accordingly, the present invention provides a wireless communication system that can flexibly respond to changes in communication conditions such as the type of communication data, the number of communication devices, and the frequency of communication, and that makes eavesdropping difficult. What you want to do.

[0009]

In order to solve the above-mentioned problems, a first aspect of the present invention is a radio communication system for performing bidirectional communication between communication apparatuses while switching frequencies according to a predetermined hopping pattern by a frequency hopping method. Wherein the hop number of the hopping pattern is changeable. As a result, it is possible to easily construct an optimal communication system corresponding to communication conditions such as the type of communication data, the number of communication devices, and the frequency of communication, and to change the hopping pattern by changing the number of hops. This has the effect of making eavesdropping difficult.

A second aspect of the present invention is the wireless communication system according to the first aspect, wherein the number of hops is changed according to the type of communication data. Thus, by changing the number of hops according to the type of communication data, it is possible to easily satisfy the conditions (real-time properties, reliability, confidentiality, etc.) that the communication data requires most.

According to a third aspect of the present invention, in the wireless communication system according to the second aspect, when the type of the communication data is voice data, the number of hops is changed so as to decrease. . As a result, it is possible to shorten the calling time required for synchronization acquisition by reducing the number of hops and improve the real-time property.

According to a fourth aspect of the present invention, in the wireless communication system according to the second aspect, when the type of the communication data is non-voice data, the number of hops is changed to increase. I have. Thereby, highly reliable communication can be performed due to an increase in the number of hops.

According to a fifth aspect of the present invention, in the wireless communication system according to any one of the first to fourth aspects, the hop number is changed during communication. Thereby, confidentiality can be improved by changing the number of hops during communication.

According to a sixth aspect of the present invention, in the wireless communication system according to any one of the first to fifth aspects, the number of hops is changed at random. Thereby, confidentiality can be further improved by changing the number of hops at random.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 2, the wireless communication system according to the present embodiment has one master device 10 (communication device) connected to an external line, and can communicate with the master device 10 and can communicate with each other. Units 11-15
(Communication device). Note that a telephone, a facsimile device, a printer, a computer, and the like can be applied to the master device 10 and the slave devices 11 to 15. Communication between master device 10 and slave devices 11 to 15 and communication between slave devices 11 to 15 are performed as shown in FIG.
uplex) system, and when one is in the transmission state (TX), the other is in the reception state (RX), and communication is performed by alternately replacing the transmission state (TX) and the reception state (RX). It is supposed to do.
Note that this wireless communication system uses TDMA (Time Division M
The communication may be performed by a utiple access) method.

The master unit 10 and the slave units 11 to 15 are
As shown in FIG. 4, there is a wireless communication unit 1 for transmitting and receiving communication data by a spread spectrum method for frequency hopping. The wireless communication unit 1 has an interface unit 21 that processes and inputs and outputs communication data to and from an external circuit (not shown). Interface unit 21
Has a codec and a compressor for mutually converting between audio data and a digital signal when the communication data is audio data, and performs a buffer and error correction processing when the communication data is non-audio data It has a data converter.

The interface unit 21 is connected to a modulator / demodulator 22 having a modulator 22a for modulating communication data and a demodulator 22b for demodulating communication data. The modulator / demodulator 22 switches the operating state of the modulator 22a and the demodulator 22b between transmission and reception of communication data by a transmission command signal p and a reception command signal q from the controller 35. Then, the modulation section 22a operated at the time of transmission is connected to an up-converter 23 having a mixer.

The up converter 23 includes a PLL.
A local oscillator 25 is connected to the PLL local oscillator 2
5, hop frequency data f1, f2,... For a plurality of channels (frequency) C1, C2,.
A hop table 26 storing fL, .. fM is connected. A hop signal r is input to the hop table 26 and the PLL local oscillator 25 every predetermined dwell time from the controller 35. The hop table 26 receives the hop signal r every time the hop signal r is input. The hop frequency data f corresponding to the channel of the channel setting value S indicated by the hop signal r is output to the PLL local oscillator 25, and the hop frequency data f
Hop frequency signal (local oscillation signal) with a frequency corresponding to
s is output to the up-converter 23. Hereinafter, when a frequency corresponding to specific hop frequency data (for example, f1) is indicated, it is indicated as, for example, frequency (f1). The up-converter 23 outputs the hop frequency signal s from the PLL local oscillator 25 and the modulation unit 22.
By adding the modulated signal t of the communication data from a, a spread modulated signal u having a spread frequency is formed.

The up converter 23 is connected to a transmission / reception switch 27 via a power amplifier 24 for amplifying the spread modulation signal u. The transmission command signal p and the reception command signal q are input from the controller 35 to the transmission / reception switch 27. When the transmission designation signal p is input, the operation state is set to the transmission enabled state and the power amplifier 24 Is transmitted from the antenna 28. On the other hand, when the reception command signal q is input, the operation state is set to the receivable state, and the spread modulation signal u received via the antenna 28 is output to the low noise amplifier 31.

The low-noise amplifier 31 is connected to a down-converter 32.
Is amplified and output. The down-converter 32 receives the hop frequency signal s input to the up-converter 23 from the PLL local oscillator 25. The down-converter 32 generates a spread modulation signal based on the hop frequency signal s. The modulated signal t is formed by despreading u, and the modulated signal t is output to the demodulation unit 22b. The demodulation unit 22b demodulates the input modulated signal t and outputs the demodulated signal t to the interface unit 21.

The wireless communication section 1 having the above-described configuration operates by being supplied with power from a power supply section 36. The power supply section 36 controls a part or the controller 35 before a communication start process. The power supply destination is set by the controller 35 so as to limit the power supply to all the wireless communication units 1 except for the power supply destination. That is, the controller 35 controls so as to supply power only to the controller 35 in the sleep mode, and controls so as to supply power except for the transmission unit including the up-converter 23 and the power amplifier 24 in the reception standby mode. In the mode, control is performed to supply power to the entire wireless communication unit 1. Further, even in the communication mode, the power may be supplied except for the up-converter and the power amplifier at the time of reception and excluding the low-noise amplifier and the down-converter at the time of transmission.

The controller 35 for controlling each section as described above executes the communication control routine shown in FIG. The communication control routine includes a paging process for transmitting a paging signal and a receiving process for receiving a paging signal so as to establish synchronization of the spread modulated signal u with the specific base unit 10 or the subunits 11 to 15 in the communication start process. After performing standby processing and establishing synchronization of the spread modulation signal u, the processing shifts to communication processing for transmitting and receiving audio data and the like.

In this communication control routine, the number of hops in the hopping pattern can be changed according to changes in communication conditions such as the type of communication data, the number of communication devices, and the frequency of communication. More specifically, at the time of communication of voice data (voice signal), as shown in FIG. 1A, a small number of hops (L) that prioritizes real-time properties is selected, and the number of hops (L) is selected. Hopping pattern. When communicating non-speech data (non-speech signal) from a computer, a facsimile machine, a printer, or the like, as shown in FIG. 1B, a large number of hops (M) with priority given to reliability are selected. Frequency hopping is performed with this hop number (M) of hopping patterns.

The operation of the wireless communication system in the above configuration will be described with reference to the flowcharts of FIGS. In the following description, a case will be described in which communication with the slave unit 11 is performed mainly on the operation of the master unit 10.

First, as shown in FIGS. 4 and 6, when the controller 35 executes the sleep mode, the power supply from the power supply unit 36 is limited to only the controller 35, and the power consumption is suppressed to a necessary minimum. (S
1). The controller 35 receiving the power supply continues to execute the communication control routine, and determines whether or not an instruction to make a call is made by checking the operation state of a call switch (not shown) or the like (S2). If it is determined that a call is to be made (S2, YES), a hop number determination process is performed so as to determine the hop number Hn according to the communication data (voice data, non-voice data) (S4).
0). The hop number determining means for determining the hop number according to the type of the communication data is configured to realize the hop number determining process.

That is, as shown in FIG. 7, it is first determined whether or not the slave unit 11 is dedicated to voice based on the ID data (S41). The number of hops Hn is set to a small value “L” so as to prioritize the characteristics.
O), it is determined whether or not the slave unit 11 is exclusively for non-voice (S43). If the handset 11 is dedicated to non-voice (S43,
YES), the hop number Hn is set to a large value “M” so as to give priority to data transfer reliability (S44). on the other hand,
If it is not dedicated to non-voice (S43, NO), then the communication data transmitted and received between the master unit 10 and the slave unit 11 based on the communication type data indicating the type of communication data (voice data, non-voice data) It is determined whether or not is audio data (S45). If the data is audio data (S45, Y
ES), the hop number Hn is set to "L" (S42), and if it is not voice data (S45, NO), the hop number Hn is set to "M" (S44). In the determination in S41 and S43, in the storage area in the controller 35, the slave unit ID data and data indicating whether the slave unit is dedicated to voice, non-voice only, or neither are stored.
The determination is made based on these data (child unit type data). When there is no ID data, only the communication type data can be determined to determine the hop number Hn.

As described above, the number of hops Hn (“L”, “H”) depends on the communication data (voice data, non-voice data).
When "M") is determined, the process returns to the communication control routine of FIG. 6 and executes a calling process (S50). When the calling process is executed, first, as shown in FIG. 8, the communication mode is set to start the power supply from the power supply unit 36 in FIG. 4 to each unit of the wireless communication unit 1, and the maximum channel count value Cmax is set to " The hop number Hn, “1” is set for the channel set value S, and “1” is set for the channel count value C (S51).

Thereafter, the controller 35 outputs the transmission command signal p to the modem 22 and the transmission / reception switch 27, thereby setting the modulation section 22a of the modem 22 to the operation state and setting the transmission / reception switch 27 to the transmission state. Set to.
Further, by outputting the hop signal r having the channel setting value “1” to the hop table 26 and the PLL local oscillator 25, the hop frequency data f1 of the first channel C1 is transmitted to the hop table 26 by the PLL local oscillator. The PLL local oscillator 25 outputs the hop frequency signal s having a frequency (f1) corresponding to the hop frequency data f1 to the up converter 23 and the down converter 32.

Next, a call signal including the ID data of the calling base unit 10, the ID data of the called side slave unit 11, the communication type data, and the hop number Hn obtained in S40 is transmitted via the interface unit 21. Into the modem 22
After being modulated by the modulator 22a, the modulated signal is output to the up-converter 23 as a modulated signal t. In the up-converter 23, the modulation signal t and the PLL local oscillator 2
5 is added to the hop frequency signal s to form a spread modulation signal u. Thereafter, the spread modulation signal u is amplified by the power amplifier 24, and then transmitted from the antenna 28 via the transmission / reception switch 27 (S52).

When the call transmission is completed in S52, the controller 35 transmits the reception command signal q to the modem 22.
And the output to the transmission / reception switch 27, the demodulation unit 22b of the modem 22 is set to the operation state, and the transmission / reception switch 27 is set to the reception state (S53).
It is determined whether or not a response signal has been received from S5 (S5).
4). If there is no response (S54, NO), the channel count value C becomes the maximum channel count value Cmax.
It is determined whether the value is smaller than (“hop number Hn”) (S55), and if it is smaller (S55, YE).
S) While the channel set value S and the channel count value C are counted up by "1" (S56), if not small (S55, NO), the channel set value S and the channel count value C are reset to "1". (S57). When a predetermined dwell time elapses by an internal timer or the like (not shown), the channel set value S
Is transmitted to the hop table 26 and the PLL.
After output to the local oscillator 25 and frequency hopping (S58), the process is re-executed from S52 to continue the calling process.

When receiving the transmission signal, the slave unit 11 on the called side confirms that the call is directed to itself, reads the hop number Hn included in the call signal, and hops the hop number Hn. Frequency hopping is started in a pattern, and a response signal is transmitted to master device 10. Then, when master device 10 receives the response signal from slave device 11 (S54, YES), channel count value C is increased to maximum channel count value Cmax (“hop number H”).
n ”) is determined (S5).
9) If the value is small (S59, YES), the channel set value S and the channel count value C are counted up by "1" (S60). If not (S59, NO), the channel set value S is incremented. And the channel count value C is reset to "1" (S61). Then, when the dwell time elapses by an internal timer or the like (not shown), a hop signal r indicating the channel set value S is output to the hop table 26 and the PLL local oscillator 25 to perform frequency hopping (S62). Frequency (fS) corresponding to hop frequency data fS of S
The communication data is transmitted (S63) and received (S64) using the spread modulated signal u. At this time, the parent device 10 and the child device 11
Performs frequency hopping with the same hop number Hn hopping pattern. Therefore, even if frequency hopping is repeated over a plurality of cycles, communication data can be transmitted and received reliably.

Thereafter, it is determined whether or not the communication has been completed (S65). If the communication has not been completed (S65, NO), the process proceeds to S65.
By re-executing from step 59, transmission / reception of communication data is continued while performing frequency hopping for each residence time,
When the communication is completed (S65, YES), the process returns to the communication control routine of FIG. 6 and shifts to the sleep mode of S1.

Next, if it is determined in S2 that the call is not to be made (S2, NO), it is determined whether or not the time has elapsed after a predetermined time has elapsed using an internal timer or the like (S3). If not up (S3, N
O) The sleep mode of S1 is continued. On the other hand, when the time is up (S3, YES), the mode is set to the reception standby mode, and power supply is started from the power supply unit 36 except for the transmission unit (the up-converter 23 and the power amplifier 24) of the wireless communication unit 1 (S4).

Then, the controller 35 outputs the reception command signal q to the modem 22 and the transmission / reception switch 27, thereby setting the demodulation unit 22b of the modem 22 to the operation state and setting the transmission / reception switch 27 to the reception state. Set. Further, the channel count value C and the channel set value S are set to “1”, and the hop signal r of the channel set value S is output to the hop table 26 and the PLL local oscillator 25. PLL of the hop frequency data f1 of the first channel C1
Output to the local oscillator 25. Then, the hop frequency signal s of the frequency (f1) corresponding to the hop frequency data f1 is represented by P
By outputting the signal from the LL local oscillator 25 to the down converter 32 (S5) and setting the down converter 32 to despread at the frequency (f1), the frequency (f1)
In a state in which the spread modulated signal u can be received (S
6).

Next, it is determined whether or not the spread modulation signal u of the frequency (f1) has been received (S7).
7, NO), it is determined whether a predetermined standby time has elapsed (S8). As the standby time, the channel count value C is counted up for each staying time, and it is determined whether the standby time has elapsed based on whether the channel count value C exceeds a predetermined value, for example, a maximum channel count value Cmax. it can. If the standby time has not elapsed (S8, N
O), S6 is re-executed and the reception standby of the frequency (f1) is continued, and when the standby time has elapsed (S8, YES), S1 is executed.
To sleep mode.

On the other hand, in S7, the handset 1 as the calling side
When the spread modulated signal u of the frequency (f1) transmitted from No. 1 is received (S7, YES), the self-call is called based on the ID data of the called side included in the received signal. It is determined whether or not there is (S9). If it is a signal calling itself (S9, YES), hop number determination processing is executed so as to determine the hop number Hn according to communication data (voice data, non-voice data) (S40).

That is, as shown in FIG. 7, first, it is determined whether or not the slave unit 11 is dedicated to voice based on the ID data (S41). The number Hn is set to “L”, and if it is not dedicated to voice (S
41, NO), it is determined whether or not the child device 11 is dedicated to non-voice (S43). If the handset 11 is dedicated to non-voice (S
43, YES), while setting the number of hops Hn to “M” (S44), while not exclusively for non-voice (S43, NO),
Subsequently, based on the communication type data, the parent device 10 and the child device 1
It is determined whether the communication data transmitted and received between the two is voice data (S45). Then, if it is voice data (S45, YES), the hop number Hn is set to "L" (S42), and if it is not voice data (S45, NO),
The hop number Hn is set to “M” (S44).

When the number of hops Hn is determined according to the communication data (voice data, non-voice data) as described above, the process returns to the communication control routine of FIG. 6 and then executes a response process (S70). When the response process is executed, FIG.
As shown in (1), a response signal including the hop number Hn obtained in S40, the ID data of the calling side, and the like is transmitted (S71).
As a result, upon receiving the response signal, the slave unit 11 as the calling side reads the hop number Hn included in the response signal and starts frequency hopping with the hopping pattern of the hop number Hn.

Thereafter, "hop number Hn" is set to the maximum channel count value Cmax so that frequency hopping is performed with the hopping pattern of the hop number Hn obtained in S40 (S72). Thereafter, the channel count value C becomes the maximum channel count value Cmax (“hop number Hn”).
It is determined whether the value is smaller than (S73). If the value is small (S73, YES), the channel set value S and the channel count value C are counted up by "1" (S74), while if not, the value is not small (S73, S73).
NO), the channel set value S and the channel count value C are reset to "1" (S75). Then, when a predetermined dwell time elapses by an internal timer or the like (not shown), a hop signal r indicating the channel set value S is output to the hop table 26 and the PLL local oscillator 25 to perform frequency hopping (S76). S
The communication data is received (S77) and transmitted (S78) with the spread modulated signal u of the frequency (fs) corresponding to the hop frequency data fs. At this time, the parent device 10 and the child device 11
Frequency hopping is performed with a hopping pattern of the same hop number Hn. Therefore, even if frequency hopping is repeated over a plurality of cycles, communication data can be transmitted and received reliably.

Thereafter, it is determined whether or not the communication has been completed (S79). If the communication has not been completed (S79, NO), transmission and reception of communication data are continued while performing frequency hopping for each residence time. When finished (S79, YE
S), the process returns to the communication control routine of FIG. 6 and shifts to the sleep mode of S1.

Next, if it is determined in S9 that the signal is not a signal calling itself (S9, NO), it is determined whether or not the standby frequency (f1) is obstructing communication by interference ( S11), if not obstructed (S1)
(1, NO), and shifts to the sleep mode of S1. The degree of frequency interference can be determined based on the error rate calculated from the data redundancy. The presence or absence of interference is determined based on whether the error rate exceeds a predetermined reference value. Is determined.

At S11, the frequency (f
If it is determined that 1) is obstructed (S11, YE
S), it is determined whether or not the standby time has elapsed (S12),
If the standby time has not elapsed (S12, NO), S6
And re-execute, and wait for reception at the current frequency (f1). On the other hand, if the standby time has elapsed (S12, YES), the current frequency (f1) on standby is the final frequency among the frequencies (f1, f2,... FL) used for reception standby. (F = fend) is determined (S10). If the frequency is the final frequency (f = fend) (S13, YES), the process shifts to the sleep mode of S1. If the frequency is not the final frequency (f = fend) (S13, NO), the channel setting value S is changed. “4”
And the channel count value C is set to “1” (S1
4) Re-execute S6 and wait for reception at the next frequency (f4).

As described above, the radio communication system according to the present embodiment, as shown in FIGS. 1A and 1B, uses the frequency hopping method to switch the frequency in accordance with a predetermined hopping pattern, and 11) When bidirectional communication is performed between each other, the number of hops (L, M) of the hopping pattern can be changed.
As a result, it is possible to easily construct an optimal communication system corresponding to communication circumstances such as the type of communication data, the number of communication devices, and the frequency of communication.

The radio communication system according to the present embodiment
By adopting a configuration in which the number of hops is changed according to the type of communication data, it is possible to easily satisfy the conditions (real-time properties, reliability, confidentiality, etc.) that the communication data most requires. ing. That is, when the type of communication data is voice data, as shown in FIG. 1A, by changing the number of hops (L) to reduce the number of hops, the time required for synchronization acquisition is shortened and real-time communication is performed. Can be improved. When the type of communication data is non-voice data,
As shown in FIG. 1B, by changing the number of hops (M) to be increased, it is possible to reduce the probability of interference and realize highly reliable communication.

The frequency at the time of standby for reception in the present embodiment does not need to be always the same, and may be set to standby at a random frequency every time the mode exits from the sleep mode. In this case, the probability of steady interference can be reduced. Further, the frequency at the time of standby for reception may be different between master device 10 and each of slave devices 11 to 15.

In the present embodiment, the change in the number of hops is performed before the start of communication. However, the present invention is not limited to this, and the change is performed during communication so as to obtain high confidentiality. It may be. Further, it is desirable that the number of hops changed before the start of communication and during communication is set at random for each change. If the number of hops is changed randomly, confidentiality can be further improved.

The hopping pattern with a random number of hops Hn will be described below, instead of the form of performing communication while frequency hopping with a hopping pattern with a fixed number of hops Hn as in the communication processing consisting of S59 to S65 in FIG. The form in which communication is performed while frequency hopping will be specifically described.

The parent device 10 and the child devices 11 to 15
As shown in FIG. 2, the hop table 37 and the hop number table 38 are provided. The hop table 37 stores hop frequency data corresponding to the frequency channels C1 to CM.
f1 to fM are stored, and in the hop number table 38,
The number of hops Hn (a ~
k) is stored. Then, the controller 35 performs communication by executing the first communication processing routine of FIG.

For example, when communication is performed between the master unit 10 and the slave unit 11 by receiving a response signal from the slave unit 11, the first communication processing routine is executed as shown in FIG. , The frequency channel count value C and the random channel count value D are set to "1" (S81). Then, the hop number Hn (D = a) corresponding to the random number channel count value D (= 1) is read from the hop number table 38, and the hop number Hn
(D = a) is set to the maximum channel count value Cmax (S82).

Next, it is determined whether or not the frequency channel count value C is smaller than the maximum channel count value Cmax (S83).
3, YES), while the channel set value S and the frequency channel count value C are counted up by "1" (S84), if not small (S83, NO), the channel set value S and the frequency channel count value C Is reset to "1", and the random number channel count value D is counted up by "1" (S85). Then, the random number channel count value D is the final value K corresponding to the last random number channel DK in the hop number table 38.
Is determined (S86), and if it is exceeded (S86).
86, YES), and reexecute from S81.

On the other hand, if not exceeded (S86, N
O), when a predetermined dwell time elapses by an internal timer (not shown) or the like, a hop signal r indicating the channel set value S is transmitted to the hop table 26 and the PLL local oscillator 25.
To the frequency hopping (S87), and the frequency corresponding to the hop frequency data fs of the channel set value S
Communication is performed using the spread modulation signal u of (fs) (S88). After this,
It is determined whether or not the communication has been completed (S89). If the communication has not been completed (S89, NO), the process is re-executed from S82 to continue the communication of the communication data, and when the communication has been completed (S89, Y).
ES), the process returns to the communication control routine of FIG. 6, and shifts to the sleep mode of S1.

Thus, master device 10 and slave device 11
Same hop table 37 and hop number table 38
Since the switching of the random number channel count value D is performed at the same timing, as shown in FIG.
Even when frequency hopping of different periods (Ta, Tb, Tc, Td) is performed with a hopping pattern of each hop number Hn (a, b, c, d), communication can be reliably continued. It has become. Since the hop number Hn of the hopping pattern changes randomly according to the hop number table 38, the hop number Hn
Since it is necessary to recognize a change in the number of hops Hn as well as the hopping pattern as compared with the case of the fixed hopping pattern, eavesdropping is extremely difficult.

Next, another embodiment in which communication is performed while frequency hopping with a hopping pattern having a random hop number Hn will be described.

The master unit 10 and the slave units 11 to 15 have the hop table 26 shown in FIG. 5, and perform communication by the controller 35 executing the second communication processing routine shown in FIG. . Then, when communication is performed between the master unit 10 and the slave unit 11 by receiving a response signal from the slave unit 11, for example, the second communication processing routine is executed as shown in FIG. It is determined whether or not the frequency channel count value C is smaller than the maximum channel count value Cmax (S9).
1) If it is a small value (S91, YES), the channel set value S and the frequency channel count value C are counted up by "1" (S92). On the other hand, if the value is not a small value (S91, NO), a random number R is generated, and the random number R is notified to the slave unit 11, whereby the maximum channel count value Cmax in the slave unit 11 is set to the random number R.
Is set (S93).

Thereafter, similarly to the slave unit 11, by setting a random number R to the maximum channel count value Cmax,
After the same maximum channel count value Cmax as that of the slave unit 11 is provided (S94), the channel set value S and the frequency channel count value C are reset to "1" (S9).
5). Then, when a predetermined dwell time elapses by an internal timer (not shown) or the like, a hop signal r indicating the channel set value S is output to the hop table 26 and the PLL local oscillator 25 to cause frequency hopping (S96).
Communication is performed using a spread modulated signal u having a frequency (fs) corresponding to the hop frequency data fs of the channel set value S (S97).
Thereafter, it is determined whether or not the communication has been completed (S98). If the communication has not been completed (S98, NO), the process is re-executed from S91 to continue the communication of the communication data.
98, YES), the process returns to the communication control routine of FIG. 6, and shifts to the sleep mode of S1.

As a result, the parent device 10 and the child device 11
Since the same hop table 26 is provided and switching of the random number R is performed at the same timing, as shown in FIG. 12, the hopping pattern differs for each hop number Hn (a, b, c, d). Period (Ta, Tb, Tc, T
Even when the frequency hopping of d) is performed, the communication can be reliably continued. In addition, since the hop number Hn of the hopping pattern changes randomly according to the random number R, the change in the hop number Hn is recognized in addition to the recognition of the hopping pattern, as compared with the case of the hopping pattern in which the hop number Hn is fixed. This makes it extremely difficult to eavesdrop.

In the above-described embodiment, the description has been given of the case where the communication between the parent and the child is applied. However, it is needless to say that the present invention can be applied to the communication between the child and the child. Also,
The number of hops can also be determined based on the number of slaves, in addition to those automatically determined based on the use of the slave and the data type. Further, the number of hops can be arbitrarily set by a manual operation switch.

[0058]

According to a first aspect of the present invention, there is provided 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 the number of hops of the hopping pattern is changed. The configuration is enabled. As a result, it is possible to easily construct an optimal communication system corresponding to communication conditions such as the type of communication data, the number of communication devices, and the frequency of communication, and to change the hopping pattern by changing the number of hops. This has the effect of making eavesdropping difficult.

According to a second aspect of the present invention, in the wireless communication system according to the first aspect, the number of hops is changed according to the type of communication data. Thus, by changing the number of hops according to the type of communication data, it is possible to easily satisfy the conditions (real-time properties, reliability, confidentiality, etc.) that the communication data requires most.

A third aspect of the present invention is the wireless communication system according to the second aspect, wherein when the type of the communication data is voice data, the number of hops is changed so as to decrease. As a result, there is an effect that the call time required for synchronization acquisition can be reduced due to the decrease in the number of hops, and the real-time property can be improved.

According to a fourth aspect of the present invention, in the wireless communication system according to the second aspect, when the type of the communication data is non-voice data, the number of hops is changed so as to increase. Thereby, there is an effect that highly reliable communication can be performed due to an increase in the number of hops.

A fifth aspect of the present invention is the wireless communication system according to any one of the first to fourth aspects, wherein the change in the number of hops is performed during communication. This allows
By changing the number of hops during communication, it is possible to increase confidentiality.

A sixth aspect of the present invention is the wireless communication system according to any one of the first to fifth aspects, wherein the number of hops is changed at random. As a result, there is an effect that the confidentiality can be further improved by randomly changing the number of hops.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a hopping pattern, wherein (a) is a hopping pattern for audio data, and (b) is a hopping pattern for non-audio data.

FIG. 2 is an explanatory diagram showing a relationship between a parent device and a child device.

FIG. 3 is an explanatory diagram showing a communication mode according to the TDD scheme.

FIG. 4 is a block diagram of a wireless communication unit.

FIG. 5 is an explanatory diagram showing data contents of a hop table.

FIG. 6 is a flowchart of a communication control routine.

FIG. 7 is a flowchart of a hop number determination processing routine.

FIG. 8 is a flowchart of a call processing routine.

FIG. 9 is a flowchart of a response processing routine.

FIG. 10 is a flowchart of a first communication processing routine.

11A and 11B are explanatory diagrams showing the data contents of each table. FIG. 11A is an explanatory diagram of a hop table, and FIG. 11B is an explanatory diagram of a hop number table.

FIG. 12 is an explanatory diagram of a hopping pattern.

FIG. 13 is a flowchart of a second communication processing routine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 wireless communication unit 10 master unit 11 to 15 slave unit 21 interface unit 22 modem 23 up-converter 24 power amplifier 25 PLL local oscillator 26 hop table 27 transmission / reception switch 28 antenna 31 low noise amplifier 32 down converter 35 controller 36 power supply unit 37 hop Table 38 Hop count table

Claims (6)

[Claims] 1. A wireless communication system for performing bidirectional communication between communication devices while switching a frequency according to a predetermined hopping pattern by a frequency hopping method, wherein the number of hops of the hopping pattern is changeable. A wireless communication system, characterized by: 2. The wireless communication system according to claim 1, wherein the number of hops is changed according to a type of communication data. 3. The wireless communication system according to claim 2, wherein when the type of the communication data is voice data, the number of hops is changed to decrease. 4. The wireless communication system according to claim 2, wherein when the type of the communication data is non-voice data, the number of hops is changed to increase. 5. The wireless communication system according to claim 1, wherein the change in the number of hops is performed during communication. 6. The wireless communication system according to claim 1, wherein the number of hops is changed at random.