JP5793768B2 - Frequency hopping method and apparatus - Google Patents

Description

  The present invention relates to a frequency hopping method and apparatus that can be used for, for example, Bluetooth (registered trademark), a wireless IC tag, data communication requiring security, or voice communication.

  In general, a transmitter / receiver using frequency hopping has many usable frequencies. However, in order to avoid interference, a frequency that can be actually used is often small because the frequency is divided and assigned. In other words, there is a possibility that a large number of transceivers (wireless stations) may be used at the same time. Since a frequency that can be used is divided and assigned to a large number of networks composed of transceivers (radio stations), there are often few hopping frequencies that can be used by one network. The control station may assign a hopping pattern that does not cause a frequency collision to a large number of networks.

  Or, if the frequency that can be used from the beginning is low, or the frequency that can be used is large and the frequency that can be theoretically used is large, do not use the frequency allocated to other transceivers (radio stations) from the viewpoint of preventing radio interference. In such cases, there are often few frequencies that can be practically used. In addition, in a large number of completely different networks with different control stations, different and independent hopping patterns with no correlation are used. Therefore, frequency collision may occur and the transmission rate due to communication failure may be reduced.

  In a frequency hopping transmitter / receiver that requires security, when the frequency used is small, a third party can intercept and easily know the frequency used. And it becomes easy for a third party to interfere with radio waves by easily knowing the frequency used. Further, there is a possibility that the effect of frequency hopping may be eliminated by the FH asynchronous receiver (FH: frequency hopping) disclosed in Patent Document 5 below. Furthermore, if the frequency used is low, even if the hopping rate is increased, radio waves at the frequency used are frequently received. Therefore, the frequency scan (frequency scanning) of the receiver used by a third party can be easily caught, and the hopping rate is increased. The effect will be reduced.

Japanese Patent Laying-Open No. 2005-45663 (page 10, FIG. 1) Japanese Patent Laid-Open No. 11-68701 (5th page, FIG. 1) JP-A-9-116526 (page 13, FIG. 1, page 14, FIG. 9) JP 2003-32739 A (page 14, FIG. 1) JP-A-11-103266 (6th page, FIG. 1)

  As described above, in a transceiver that uses frequency hopping, there is a limit to the frequency that can be actually used. Therefore, an independent hopping pattern that has no correlation with neighboring networks in a network that is supposed to be able to use many transceivers simultaneously. , Even if the hopping pattern is changed or the hopping rate is increased, there is a high possibility that many frequency collisions occur and the number of retransmissions tends to increase, and the transmission rate cannot be increased, It was an obstacle to high-speed data transmission or high-quality voice communication. Also, if there are many frequency collisions, the noise during reception increases, the signal-to-interference ratio (S / J) or the signal-to-noise ratio (S / N) deteriorates, and this is a factor that shortens the communication distance between the transceivers. It was also.

  In a frequency hopping transmitter / receiver that requires security, if the frequency used is small, even if the hopping rate is increased, the third party can easily receive or intercept the frequency used, and the third party can It was possible to easily and effectively jam using jamming radio waves. Alternatively, a third party could eliminate the hopping effect and make it as if it were receiving on one frequency.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a frequency hopping method and apparatus capable of effectively avoiding frequency collision and improving security even when usable frequencies are limited. It is to provide.

The first aspect of the present invention is a frequency hopping method. In this method, a first hopping pattern having a first period and hopping a wide frequency range at a wide frequency interval and a narrow frequency range having a second period different from the first cycle at a narrow frequency interval are hopped. A frequency hopping method of combining a second hopping pattern and performing frequency hopping of an oscillation frequency by one local oscillator based on the combined hopping pattern ,
In the second hopping pattern, each frequency included in the first hopping pattern is changed within the occupied bandwidth assigned to the frequency.

The second aspect of the present invention is a frequency hopping method. In this method, a first hopping pattern having a first period and hopping a wide frequency range at a wide frequency interval and a narrow frequency range having a second period different from the first cycle at a narrow frequency interval are hopped. A frequency hopping method for performing frequency hopping of an oscillation frequency obtained by combining a second hopping pattern and selecting one of the oscillation outputs of a group of local oscillators based on the combined hopping pattern. ,
In the second hopping pattern, each frequency included in the first hopping pattern is changed within the occupied bandwidth assigned to the frequency.

In the second aspect, which local oscillator is used at a predetermined frequency may be switched.

In the second aspect, while using a certain local oscillator, the local oscillator to be used next may oscillate in advance.

In the second aspect, after the use of a certain local oscillator is started, the oscillation of the previously used local oscillator may be terminated.

In the first or second aspect, when the number of frequencies included in the first hopping pattern is n and the number of frequencies included in the second hopping pattern is m, the frequency is included in the synthesized hopping pattern. The number of frequencies to be transmitted may be n × m.

In the first or second aspect, a plurality of the first and second hopping patterns may be prepared, and the combination of the first and second hopping patterns to be combined may be changed at a predetermined timing. .

According to a third aspect of the present invention, there is provided a frequency hopping apparatus including a single local oscillator and a control unit that controls the local oscillator, the control unit having a first frequency and a wide frequency range. A memory that stores a first hopping pattern that hops at an interval and a second hopping pattern that has a second period different from the first period and hops a narrow frequency range at a narrow frequency interval; Hopping the oscillation frequency of the local oscillator based on a hopping pattern obtained by combining the first and second hopping patterns ,
In the second hopping pattern, each frequency included in the first hopping pattern is changed within the occupied bandwidth assigned to the frequency.
A fourth aspect of the present invention is a frequency hopping device, comprising a group of local oscillators and a control unit that controls the group of local oscillators, the control unit having a first period and a wide frequency range. A memory storing a first hopping pattern that hops at a wide frequency interval and a second hopping pattern that has a second period different from the first period and hops a narrow frequency range at a narrow frequency interval; Hopping an oscillation frequency obtained by selecting one of the oscillation outputs of the group of local oscillators based on a hopping pattern obtained by combining the first and second hopping patterns,
In the second hopping pattern, each frequency included in the first hopping pattern is changed within the occupied bandwidth assigned to the frequency.

In the fourth aspect, the control unit may switch which local oscillator is used at a predetermined frequency.

In the fourth aspect, there is provided selection means for selecting any one of the output signals of the group of local oscillators and inputting the selected signal to a mixer, and the control unit selects the output signal of a local oscillator and The local oscillator to be selected may be oscillated in advance.

In the fourth aspect, after the output signal of a certain local oscillator is selected, the control unit may end the oscillation of the local oscillator used previously.

  It should be noted that any combination of the above-described constituent elements, or a conversion of the expression of the present invention between systems or the like is also effective as an aspect of the present invention.

  According to the present invention, it is possible to provide a frequency hopping method and apparatus capable of effectively avoiding frequency collision and improving security even when usable frequencies are limited.

The block diagram which shows the basic composition of the transmitter / receiver which concerns on embodiment of this invention. FIG. 4 is an explanatory diagram showing a relationship between a frequency that can be actually used and a frequency that can be theoretically used with respect to the hopping frequency. Explanatory drawing which extracted the frequency which can be actually used among the frequencies shown in FIG. FIG. 9 is an explanatory diagram showing a relationship in which a hopping pattern to be used is selected from a plurality of hopping patterns stored in the signal processor 11 and frequency information is transmitted to the PLL local oscillator 7 with respect to a conventional example. Hopping patterns (hopping patterns 1 and 2) that can be used in an ideal environment with no radio wave interference with other radio stations or transceivers, and hopping patterns created using frequencies that can actually be used in business (hopping patterns) Explanatory drawing which shows the difference about A, B), and the characteristic about those hopping patterns and secrecy. Regarding the embodiment, in addition to the hopping patterns shown in FIG. 4, hopping patterns (deviation patterns A and B) that improve the avoidance of frequency collision are further stored in the signal processor 11 and used from among them. Explanatory drawing which showed the relationship which selects a hopping pattern and transmits frequency information to the PLL local oscillator. FIG. 6 is an explanatory diagram illustrating deviation amounts and deviation changes of deviation patterns A and B in addition to the hopping patterns shown in FIG. 5 according to the embodiment. Explanatory drawing explaining the relationship between the oscillation frequency and step interval of the PLL local oscillator 7 of the past and embodiment. The structure explanatory drawing of the PLL local oscillator 7 corresponding to high speed hopping and a stable frequency output regarding embodiment. The time chart of the output of the PLL local oscillator 7 of FIG. Explanatory drawing of the bandwidth and guard band of the modulation | alteration received wave in the adjacent hopping frequency. The shape explanatory drawing of the spectrum of the received wave converted into the intermediate frequency. FIG. 8 is an explanatory diagram showing a relationship between a target received wave and a superimposed narrow-band jamming (interference) wave at the frequency of the hopping pattern A shown in FIG. 7. FIG. 7 is an explanatory diagram showing the relationship between a target received wave at a frequency obtained by adding the frequency of the deviation pattern A to the frequency of the hopping pattern A shown in FIG. 7 and the superimposed narrowband interference (interference) wave in the embodiment. . FIG. 8 is an explanatory diagram showing a relationship between a target received wave at a frequency obtained by adding the frequency of the deviation pattern A to the frequency of the hopping pattern A shown in FIG. 7 and a superimposed broadband interference (interference) wave in the embodiment. Regarding the embodiment, the relationship between the target received wave at the frequency obtained by adding the frequency of the deviation pattern A to the frequency of the hopping pattern A illustrated in FIG. 7 and the superimposed modulated wave (interference wave) with the same center frequency shifted. Explanatory drawing which showed.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, process, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  FIG. 1 is a block diagram showing a basic configuration of a transceiver according to an embodiment of the present invention. This transceiver is, for example, a transceiver for performing frequency hopping used for Bluetooth (registered trademark) or a wireless IC tag, or a transceiver for performing frequency hopping requiring security, and is assumed to be able to use many transceivers simultaneously. It is assumed that a transceiver that uses a frequency hopping pattern that has no correlation with a neighboring network and that may cause a frequency collision with the neighboring network.

  As shown in FIG. 1, the transceiver of the present embodiment includes a bandpass filter 1 that allows only radio waves in the used frequency band to pass through, a transmission / reception switcher 2 that can switch transmission and reception at high speed according to the control of the signal processor 11, and transmission An amplifier 3 for amplifying radio waves to a specified output power, a mixer 4 for a transmitter that mixes an IF (intermediate frequency) signal and a PLL local oscillator signal, or a mixer for a receiver that mixes a received radio wave and a PLL local oscillator signal 4, an IF amplifier 5 that amplifies an IF (intermediate frequency) signal, a modulator 6 that places modulation data on a reference signal output from an oscillator 8, a PLL local oscillator 7 that oscillates and outputs a reference signal having a hopping frequency, An oscillator 8 that oscillates and outputs an (intermediate frequency) signal, an amplifier 9 that amplifies weak received radio waves, a demodulator 10 that extracts baseband data from the IF signal, Selection of ring patterns, control of the PLL local oscillator 7 or the duplexer 2, and a signal processor 11 serving as a control section for processing and separation of data transmitted and received, and an antenna 16.. The receiving unit in this block diagram is a single superheterodyne system as a simple configuration, but a system using a multistage IF such as a double superheterodyne system may be used.

  FIG. 2 is an explanatory diagram showing a relationship between a frequency that can be actually used and a frequency that can be theoretically used with respect to the hopping frequency. In FIG. 2, the frequency that can actually be used is a frequency that can be used by the transceiver in advance by negotiating the used frequency in advance in order to avoid a frequency collision with a transceiver of another network or another radio station, for example. In addition, the frequency that can be used theoretically is that the frequency is allocated and can be used, but in order to avoid frequency collision with other network transceivers or other radio stations, the frequency used can be negotiated in advance. It is the frequency at which it paused. However, if it is difficult to negotiate the frequency used in advance, or if there is no correlation with other networks, there will be no distinction between the frequency that can actually be used for business and the frequency that can be used theoretically, and all frequencies will be used. Can also be made, and collisions often occur. In FIG. 2, the solid lines (f1, f4, f8, etc., which are actually usable frequencies) and the dotted lines (f2, f3, f5, etc., which are theoretically usable frequencies) are not arranged at equal intervals, but the oscillation of the PLL local oscillator 7 According to the frequency step, for example, the frequency may be arranged every 10 KHz.

  FIG. 3 is a diagram in which the solid line portion of FIG. 2 is extracted, and is a diagram that makes it easy to understand that there are few frequencies that can actually be used.

  FIG. 4 is an explanatory diagram showing a relationship of selecting a hopping pattern to be used from among a plurality of hopping patterns stored in the signal processor 11 and transmitting frequency information to the PLL local oscillator 7 with respect to the conventional example. . In FIG. 4, for example, there are four types of hopping patterns, and one of these is selected, frequency information that changes every moment according to the selected hopping pattern is sent to the PLL local oscillator 7, and the PLL local oscillator 7 is controlled. Yes.

  FIG. 5 illustrates the hopping pattern described in FIG. 4, and hopping patterns 1 and 2 are hopping patterns created using frequencies that can actually be used and frequencies that can be theoretically used. On the other hand, hopping patterns A and B are hopping patterns created using only frequencies that can actually be used. Note that the hopping periods of the hopping patterns A and B are shorter than the hopping patterns 1 and 2 because the usable frequency is small.

  Conventionally, in order to improve confidentiality, the hopping rate is increased as shown in the lower part of FIG. For example, in Bluetooth (registered trademark) used as a general purpose, 79 waves are used for each 1 MHz in the 2.4 GHz band, and hopping is performed at a rate of 1,600 times / second. In addition, in transceivers requiring security, for example, in the US military standard Fighter Data Link 16, hopping is performed at a rate of 77,800 times / second.

  However, even if the hopping rate is increased, if the frequency used is small, the probability of being easily caught by a third party receiver increases. In addition, if Max hold reception is performed with a measuring instrument such as a spectrum analyzer, a bright line of the used frequency is easily established and the used frequency is known.

  FIG. 6 relates to the embodiment, in addition to the hopping patterns shown in FIG. 4, hopping patterns (deviation patterns A and B) that improve the avoidance of frequency collision are further stored in the signal processor 11. It is explanatory drawing which showed the relationship which selects the hopping pattern to be used from among and transmits frequency information to the PLL local oscillator. The hopping patterns 1 and 2 and the hopping patterns A and B are examples of the first hopping pattern, and the deviation patterns A and B added in FIG. 6 are examples of the second hopping pattern. The hopping periods of the first and second hopping patterns are different from each other.

  In FIG. 6, as an example, the frequency information of the hopping pattern A selected from the first hopping pattern and the frequency information of the deviation pattern A selected from the second hopping pattern are synthesized, and the synthesis is performed. The value is sent from the signal processing unit 11 to the PLL local oscillator 7 to control the PLL local oscillator 7. By causing the PLL local oscillator 7 to oscillate the frequency based on the synthesized value, frequency collisions are reduced, the number of data retransmissions is reduced, and high-speed data transmission is enabled as a result. Further, the mutual interference of the frequency is reduced and the noise level is reduced. As a result, it is possible to improve the voice communication with high sound quality and the communication distance. If the number of frequencies included in the first hopping pattern is n and the number of frequencies included in the second hopping pattern is m, the number of frequencies included in the hopping pattern obtained by synthesizing the first and second hopping patterns. Is at most n × m. Note that the combination of the first and second hopping patterns to be combined is changed when a preset time and the number of cycles are reached, or based on a preset usage table (a table storing information related to switching of combinations). You may do it.

  The hopping patterns 1 and 2 and the hopping patterns A and B may be a hopping pattern after combining a hopping pattern of one sequence and a hopping pattern of another sequence, that is, a hopping pattern after multiple combining. The random number sequence to be can be made by multiple synthesis. However, in the hopping patterns 1 and 2 and the hopping patterns A and B, the frequency information instructed by the combined hopping pattern is not slightly changed within an occupied bandwidth of a certain basic frequency.

  FIG. 7 illustrates the hopping pattern described in FIG. 6, and the variation range of the hopping frequencies of the deviation patterns A and B is small. For example, the hopping patterns 1 and 2 and the hopping patterns A and B range from 100 MHz to 200 MHz as shown in FIG. On the other hand, the deviation patterns A and B have a change range of ± 10 KHz. That is, in the present embodiment, the oscillation frequency of the PLL local oscillator 7 is changed within the occupied bandwidth of each frequency included in the hopping patterns 1 and 2 and the hopping patterns A and B by combining the deviation patterns A and B. .

  FIG. 8 is an explanatory diagram for explaining the relationship between the oscillation frequency and the step interval of the PLL local oscillator 7 according to the related art and the embodiment. The conventional PLL local oscillator 7 has a drawback in that the step interval of the frequency that can be oscillated is increased (or the number of channels is reduced) in order to cope with a wide oscillation frequency band. In order to improve the increase in the step interval, the present PLL local oscillator 7 uses the first PLL local oscillator 12 and the second PLL local oscillator 13 in parallel, and the oscillation frequency of each PLL local oscillator Dividing the obi. Note that the number of PLL local oscillators used in parallel may be three or more, and is determined by the step interval of the output frequency.

  FIG. 9 is an explanatory diagram of the configuration of the PLL local oscillator 7 corresponding to the high-speed hopping and the stable frequency output according to the embodiment. FIG. 9 shows a method different from that in FIG. 8. In order to use four PLL local oscillators in parallel and correspond to a fast hopping rate, a first PLL local oscillator 12 and a third PLL local oscillator 14 are used. Is a group in charge of the low frequency side, and the second PLL local oscillator 13 and the fourth PLL local oscillator 15 are in charge of the high frequency side. Such a method is effective when the output frequency for which one set is in charge is selected continuously. That is, for example, the oscillation of the third PLL local oscillator 14 is started while the oscillation output of the first PLL local oscillator 12 is selected, and then the third PLL local oscillator 14 at a stage where the oscillation frequency is stabilized. By selecting this oscillation output, a stable frequency with no frequency change at the rise and no frequency change at the fall can be used as the oscillation output of the PLL local oscillator 7. The number of PLL local oscillators used in parallel may be five or more, and the number of PLL local oscillators included in each group may be different (for example, one group uses two in parallel and the other group uses three. Are used in parallel). Further, the number of PLL local oscillators used in parallel may be three or more. The selection of the PLL local oscillator may be performed by opening and closing a gate (not shown) provided on the output side of each PLL local oscillator under the control of the signal processor 11.

  FIG. 10 is a time chart of the output of the PLL local oscillator 7 of FIG. The vertical axis in FIG. 10 does not clearly represent the oscillation frequency as an absolute value, but represents it as a relative value, but it can be seen that the oscillation frequency changes with time. The frequency of the oscillation output of the PLL local oscillator 7 changes with the passage of time t1, t2, t3... (Refer to the time chart at the top). In addition, a blank time during which no radio wave is emitted, that is, a guard time is provided at the rear of each time. The guard time takes into account the delay due to the distance between the transmitter and receiver, and when the transmitter / receiver is at the maximum communication distance, when a transmitter / receiver transmits after receiving the received wave, the received wave is received to the end. Can be sent from. The guard time also includes the purpose of buffering a slight time synchronization difference between the transceivers.

  The time charts at the second and lower stages in FIG. 10 show waveforms of oscillation frequencies of the PLL local oscillators (first PLL local oscillator 12 to fourth PLL local oscillator 15) included in the PLL local oscillator 7. Since the output frequency is low during the period from t1 to t3 and the period from t6, the set of the first PLL local oscillator 12 and the third PLL local oscillator 14 is in charge. On the other hand, since the output frequency is high during the period t4 and t5, the set of the second PLL local oscillator 13 and the fourth PLL local oscillator 15 is in charge.

  The frequencies fp, fq, fx, and fy indicate any of the frequencies (f1 to fn) constituting the hopping patterns 1 and 2 or the hopping patterns A and B shown in FIG. In the time chart of the second stage and below in FIG. 10, the frequencies fp, fq, fx, and fy are indicated by horizontal straight lines, but the frequencies indicated by the frequencies fp, fq, fx, and fy are controlled by the signal processor 11. It can change every period shown by t1, t2, t3.

  The waveform in which overshoot is observed in the time charts in the second and lower stages of FIG. 10 is a waveform showing a change in the actual oscillation frequency of the first PLL local oscillator 12 to the fourth PLL local oscillator 15, and the frequency fp, This corresponds to a combination of the frequency of deviation pattern A or deviation pattern B shown in FIG. 7 with respect to fq, fx, and fy. Changes in the oscillation frequency, overshoot, and undershoot appear when each PLL local oscillator rises and falls. For this reason, the signal processor 11 oscillates each PLL local oscillator in advance (during use of another PLL local oscillator) before selecting the oscillation output of the PLL local oscillator. The signal processor 11 also ends the oscillation of each PLL local oscillator after the use of the next PLL local oscillator is started. For example, the signal processor 11 starts the oscillation of the next third PLL local oscillator 14 during the period t1 when the first PLL local oscillator 12 is oscillating, and the oscillation output of the third PLL local oscillator 14 The oscillation of the third PLL local oscillator 14 is ended after the period t2 (period t3) when is selected. As a result, even when the hopping rate is high, the output of the PLL local oscillator 7 has no frequency change at the rise and no frequency change at the fall of the first PLL local oscillator 12 to the fourth PLL local oscillator 15. It becomes possible to use a stable frequency.

  FIG. 11 is an explanatory diagram of the bandwidth and guard band of the modulated received wave at adjacent hopping frequencies, and is a schematic diagram of the spectrum of the radio wave output from the amplifier 9 of FIG. It should be noted that since the spectrums with the center frequencies f8 and f9 are hopping, they do not actually appear at the same time, but the figure shows both spectra for easy understanding.

  In the example of FIG. 11, the received signal has a bandwidth of 40 KHz, a guard band of 5 KHz, and the radio wave spectrum has a mountain shape. The reason why the spectrum has a mountain shape is that the generation of spurious such as harmonics is blocked by the mountain-shaped pass characteristic of a bandpass filter (or intermediate frequency filter) (not shown) in the modulator 6. Further, an IF (intermediate frequency) signal that has passed through the mixer 4 of the receiving section as shown in FIG. 12 due to the mountain-shaped pass characteristic of a bandpass filter (or intermediate frequency filter) (not shown) in the demodulator 10 is further obtained. The spectrum becomes Yamagata. The guard band is set for the purpose of buffering mutual frequency interference caused by a frequency shift caused by a difference in frequency oscillation accuracy and stability of the PLL local oscillator of each transceiver. The guard band is also intended to buffer frequency shifts due to the Doppler effect when either or both of the transceivers move.

  By making the spectrum ram of the received signal chevron by the filter and the presence of the guard band, the deviation amounts of the deviation patterns A and B shown in FIG. Often, collisions between radio waves with the same center frequency are avoided.

  FIG. 13 is an explanatory diagram showing a relationship between a target received wave and a superimposed narrowband interference (interference) wave at the frequency of the hopping pattern A shown in FIG. FIG. 13 shows a case where CW (non-modulation) is superimposed on the center frequency of f1 or f21 as interference or interference wave. Note that the spectrums with the center frequencies f1 and f21 are actually hopping, so they do not actually appear at the same time, but the figure shows both spectra for ease of explanation. In the case of FIG. 13, for example, when the total received power (total value of each spectrum) of the radio wave having the center frequency f1 is −80 dBm and the interference (interference) wave is −86 dBm, demodulation becomes difficult, but interference (interference) ) The wave can be demodulated at -87 dBm. That is, S / N (or S / J) requires 7 dB for demodulation.

  FIG. 14 shows the relationship between the target received wave at the frequency obtained by adding the frequency of the deviation pattern A to the frequency of the hopping pattern A shown in FIG. 7 and the superimposed narrowband interference (interference) wave in the embodiment. It is explanatory drawing shown. FIG. 14 shows a case where CW (non-modulation) is superimposed on f1 and f21 (center frequency before adding the frequency of the deviation pattern A) as interference or interference wave. Note that the spectrums with the center frequencies of f1 + 5 KHz and f21-12 KHz are actually hopping, so they do not actually appear at the same time, but the figure shows both spectra for easy understanding. In the case of FIG. 14, for example, when the total received power (total value of each spectrum) of a radio wave having a center frequency of f1 + 5 KHz is −80 dBm and the interference (interference) wave is −84 dBm, demodulation becomes difficult, but interference (interference) The wave can be demodulated at -85 dBm. That is, S / N is required to be 5 dB for demodulation. Similarly, for example, when the total received power (total value of each spectrum) having a center frequency of f21-12 KHz is −80 dBm and the interference (interference) wave is −81 dBm, it is difficult to demodulate, but the interference (interference) wave is − Demodulation is possible at 82 dBm. That is, S / N of 2 dB is required for demodulation.

  FIG. 15 shows the relationship between the target received wave at the frequency obtained by adding the frequency of the deviation pattern A to the frequency of the hopping pattern A shown in FIG. FIG. In the example of FIG. 13, it is difficult to demodulate when the total received power (total value of each spectrum) of the radio wave having the center frequency f1 is −80 dBm and the interference (interference) wave is −86 dBm. As described above, as a result of widening the interference (interference) wave to correspond to the frequency of the f1 + deviation pattern A, the peak power of the interference (interference) wave becomes −96 dBm, for example. If this -96 dBm is simply considered as N (noise) in the same manner as CW, it becomes an example in which the interference effect is completely eliminated because N is further reduced by 10 dB. In order to produce the effect of a wideband jamming wave, the power value at f21 needs to be −86 dBm when simply considered like the jamming (interference) wave superimposed on the radio wave having the center frequency of f21-12 KHz in FIG. . Since the bandwidth is actually increased, the total power value of N (noise) for obtaining the interference effect is, for example, −78 dBm.

From the above, the synthesis of the hopping pattern A and the deviation pattern A makes it difficult for a third party to interfere as described below.
1 When receiving radio waves, regularity of reception frequency is lost, and high-speed synchronization and stable reception cannot be performed.
2. When interfering with radio waves, it is not possible to use CW effective for interfering, and it is necessary to transmit broadband radio waves. However, since the transmission power per unit frequency becomes small, effective interference cannot be made.

  FIG. 16 is related to the embodiment, and a target received wave at a frequency obtained by adding the frequency of the deviation pattern A to the frequency of the hopping pattern A shown in FIG. It is explanatory drawing which showed the relationship of the wave. The interference wave superimposed in FIG. 16 is a data signal wave emitted from a transmitter / receiver in a nearby network similar to the transmitter / receiver, and the center frequency is deviated from the target received wave. Note that frequency collision with a neighboring network occurs when there is no correlation between the hopping pattern of the transceiver and the hopping pattern of the transceiver of the neighboring network.

  When the interference wave as shown in FIG. 16 is superimposed, the noise N (noise) increases, and the S / N of the IF signal of the transceiver becomes worse. However, from the description of FIG. 13 and FIG. 14 described above, since the center frequency of the interference wave is deviated from the target reception wave, the noise level is slightly reduced, and the loss of the reception wave is reduced. As a result, missing baseband data after demodulation in the demodulator 10 is reduced, and it becomes possible to improve the transmission rate, improve voice communication with high sound quality, and improve the communication distance. The fact that the transmission rate can be increased means that the amount of data transmission per unit time increases, and it is not necessary to increase the hopping rate and reduce the baseband data amount even if the control data accompanying hopping increases. Therefore, the hopping rate can be improved.

  According to the present embodiment, the following effects can be achieved.

(1) The passband width of the receiver usually has a mountain shape due to the characteristics of the filter, and the influence from other signals, that is, noise, decreases as the distance from the center frequency of the passband increases. Therefore, by combining the deviation pattern as in the present embodiment, complete frequency collision with radio waves emitted by other transceivers having different hopping frequencies is often avoided, and S / N or S / J And is less affected by nearby uncorrelated transceivers or networks, and as a result, high-speed data transmission or high-quality voice communication and communication distance can be improved.

(2) Since a large number of operating frequencies are generated, the frequency of integration of the same frequency is reduced, and for third-party receivers, the reception scan (reception scanning) function is disabled as the reception level decreases. As a result, it is difficult to perform radio wave interference. In addition, even if a CW interference or a broadband interference due to a modulated wave is received, the effect can be reduced.

(3) Due to the large number of frequencies used, the received signal is positioned at the center of the pass bandwidth even for receivers that require a large number of local oscillators, such as the FH asynchronous receiver of Patent Document 5. The effect of removing hopping can be reduced due to a decrease in the signal level after demodulation.

(4) If the combination of hopping patterns to be combined (the combination of the hopping pattern and the deviation pattern in FIG. 7) reaches a preset time and the number of cycles, or if it is changed based on a preset usage table, It is possible to invalidate the reception scan (reception scan) function of the third-party receiver.

(5) If a PLL local oscillator in charge of the high frequency side and a PLL local oscillator in charge of the low frequency side are used in parallel, the frequency resolution can be increased and the step interval of the oscillating frequency can be reduced.

(6) If a plurality of PLL local oscillators in charge of the same frequency range are used, as described with reference to FIG. 10, a frequency excluding a portion with a distorted frequency at the rise and fall of the oscillation should be selected and used. Thus, the stability of the oscillation frequency can be improved.

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way.

1 BPF (band pass filter), 2 duplexer, 3 amplifier, 4 mixer, 5 IF amplifier, 6 modulator, 7 PLL local oscillator, 8 oscillator, 9 amplifier, 10 demodulator, ll signal processor, 12th 1 PLL local oscillator, 13 2nd PLL local oscillator, 14 3rd PLL local oscillator, 15 4th PLL local oscillator, 16 antenna

Claims (12)

A first hopping pattern having a first period and hopping a wide frequency range at a wide frequency interval, and a second hopping having a second period different from the first cycle and hopping a narrow frequency range at a narrow frequency interval A frequency hopping method for combining a pattern and performing frequency hopping of an oscillation frequency by one local oscillator based on the combined hopping pattern ,
The second hopping pattern is a frequency hopping method in which each frequency included in the first hopping pattern is changed within an occupied bandwidth assigned to the frequency. A first hopping pattern having a first period and hopping a wide frequency range at a wide frequency interval, and a second hopping having a second period different from the first cycle and hopping a narrow frequency range at a narrow frequency interval A frequency hopping method for performing frequency hopping of an oscillation frequency obtained by selecting one of the oscillation outputs of a group of local oscillators based on the synthesized hopping pattern,
The second hopping pattern is a frequency hopping method in which each frequency included in the first hopping pattern is changed within an occupied bandwidth assigned to the frequency. The frequency hopping method according to claim 2 , wherein which local oscillator is used at a predetermined frequency is switched. 4. The frequency hopping method according to claim 2 , wherein a local oscillator to be used next is oscillated in advance while using a certain local oscillator. The frequency hopping method according to any one of claims 2 to 4 , wherein after the use of a certain local oscillator is started, the oscillation of the local oscillator used previously is terminated. When the number of frequencies included in the first hopping pattern is n and the number of frequencies included in the second hopping pattern is m, the number of frequencies included in the synthesized hopping pattern is n × m. The frequency hopping method according to any one of claims 1 to 5 . The advance first and second hopping patterns to each of the plurality preparation, changing the combination of the first and second hopping pattern synthesized with a predetermined timing, according to any one of claims 1 to 6 Frequency hopping method. One local oscillator and a control unit for controlling the local oscillator, the control unit having a first period and hopping a wide frequency range at a wide frequency interval; and the first hopping pattern A second hopping pattern having a second period different from the period and storing a second hopping pattern for hopping a narrow frequency range at a narrow frequency interval, and based on a hopping pattern obtained by synthesizing the first and second hopping patterns A frequency hopping device for hopping the oscillation frequency of the local oscillator,
The second hopping pattern is a frequency hopping device that adds a variation to each frequency included in the first hopping pattern within an occupied bandwidth assigned to the frequency. A group of local oscillators, and a control unit that controls the group of local oscillators, the control unit having a first period and hopping a wide frequency range at a wide frequency interval; and A second hopping pattern having a second period different from the first period and storing a second hopping pattern for hopping a narrow frequency range at a narrow frequency interval, and combining the first and second hopping patterns into a hopping pattern A frequency hopping device for hopping an oscillation frequency obtained by selecting one of the oscillation outputs of the group of local oscillators based on:
The second hopping pattern is a frequency hopping device that adds a variation to each frequency included in the first hopping pattern within an occupied bandwidth assigned to the frequency. The frequency hopping device according to claim 9 , wherein the control unit switches which local oscillator is used with a predetermined frequency as a boundary. Selecting means for selecting any one of the output signals of the group of local oscillators and inputting the selected signal to the mixer, and the control unit selects a local oscillator to be selected next while an output signal of a certain local oscillator is being selected in advance. The frequency hopping device according to claim 9 or 10 , which oscillates. The frequency hopping device according to any one of claims 9 to 11 , wherein the control unit terminates the oscillation of a local oscillator that has been used before, after an output signal of a certain local oscillator is selected.