JP2011188316A - Frequency hopping radio communication device and frequency hopping method of the same, and transmitter and receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frequency hopping radio communication device that reduces scale and load of an RF part and enhances interference resistance, and to provide a frequency hopping method thereof, and transmitter and receiver. <P>SOLUTION: A frequency hopping radio communication device 1 includes: a transmitter 11 for transmitting a reference information signal at predetermined intervals with an arbitrary frequency band and in an arbitrary hopping pattern; and a receiver 21 that receives a signal including the hopping pattern, performs discrete Fourier transform on the received signal, detects frequency of the hopping signal, and demodulates the frequency-detected hopping signal to obtain the reference information signal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a frequency hopping radio communication device, a frequency hopping method thereof, a transmission device, and a reception device, and more particularly to a technology for providing confidentiality to communications of land mobile radio devices and mobile radio devices mounted on ships and aircraft.

  In the wireless communication apparatus using the frequency hopping method related to the present invention, the hopping timing (hopping time) is used to synchronize the hopping frequency in both the transmitting wireless station that transmits information and the receiving wireless station that receives information. And a time table (hopping time table) indicating the changing frequency, and the transmitting radio station and the receiving radio station exchange information according to the hopping time table while changing the transmission frequency and the receiving frequency.

  Therefore, if the wireless communication device does not have a GPS (Global Positioning System) reception function for sharing the hopping time, the receiving wireless station cannot synchronize with the transmitting wireless station, and thus changes in real time. The phases of the hopping timetable could not be matched.

  On the other hand, an example of related technology for synchronizing a receiving radio station with a hopping frequency generated on the transmitting radio station side is known. FIG. 9 is a schematic diagram showing an example of a hopping frequency synchronization method in the related art. In the figure, the vertical axis represents hopping frequency (Hz) and the horizontal axis represents time (sec.).

  As shown in the figure, a known frequency (hereinafter referred to as “reference information signal”) is transmitted from the transmitting wireless station side at a fixed period, and the receiving wireless station side waits at that frequency and detects the reference information signal. As a result, time synchronization is subordinately performed.

  Here, the reference information signal is called a network time reference (hereinafter referred to as “NTR”) signal or a beacon signal, and includes a time stamp, a hopping pattern, an NTR cycle, information on a network to join, etc. Information that is indispensable for establishing communication.

  On the other hand, since the NTR signal has a periodic and known frequency, a third party for the purpose of disturbance can monitor the power spectrum of the frequency band for a certain period to detect the presence of the NTR signal and perform disturbance or the like. The NTR signal cannot be captured on the receiving radio station side, and there is a risk that communication may not be established between the transmitting and receiving radio stations.

  On the other hand, it is possible to transmit the NTR signal with a limited hopping pattern without setting the NTR signal to a known constant frequency in order to prevent the third party for disturbance from detecting the NTR signal. FIG. 10 is a schematic diagram showing another example of the hopping frequency synchronization method in the related art. In the figure, the vertical axis represents hopping frequency (Hz) and the horizontal axis represents time (sec.).

  Referring to the figure, in another example of the related art, an NTR signal is divided by a known hopping frequency pattern on the transmitting radio station side and received in accordance with a known hopping frequency pattern on the receiving radio station side, whereby the NTR signal is received. Getting a signal.

  On the other hand, in order to demodulate an unknown hopping frequency, a method of using an analog element, for example, a SAW (Surface Acoustic Wave) element as a dispersion delay line or the like is known. However, analog elements have drawbacks that their characteristics are likely to change due to their temperature characteristics, aging, etc., and that the parameters cannot be easily changed.

  A related technique for solving this drawback is disclosed in Patent Document 1. This is because the receiving side detects the hopping frequency interval and the hopping frequency from the received signal in the frequency detection unit using DFT (Discrete Fourier Transform) by a process combining high-speed Fourier transform and a filter bank circuit. Information is demodulated by despreading with a frequency pattern based on the frequency code used for spreading on the transmission side.

  Another example of related technology is disclosed in Patent Document 2. This is a method of synchronizing a receiver to a received orthogonal frequency division multiplexed (OFDM) signal having a preamble with short and long duration codes, which transforms the received OFDM signal into frequency domain components by Fourier transform. And processing the frequency domain components into timing components; extracting timing information from the timing components; and applying timing information to the received OFDM signal to synchronize the receiver, all of the above steps Is performed during one of the short codes.

  An example of other related technology is disclosed in Patent Document 3. This relates to a wireless communication device, and the wireless communication device includes a baseband processing circuit, two wireless devices, and two antennas. The baseband processing circuit has a function of performing hopping pattern generation processing for frequency hopping. In addition, the two wireless devices perform frequency hopping processing in synchronization with each other using an arbitrary hopping pattern. Then, at the time of reception, the two wireless devices have a function of selecting received data that has not been detected in error.

  Another example of related technology is disclosed in Patent Document 4. This relates to constrained hopping and channel estimation in wireless communication systems. In this wireless communication system, a user is scheduled in a frequency band divided into one or a plurality of sub-regions. Then, by dividing the entire bandwidth into a plurality of subbands, the hopping pattern is constrained so that subcarriers in a predetermined subband always hop within the same subband.

Japanese Patent Laid-Open No. 11-251969 JP 2002-185428 A JP 2009-005037 A Special table 2008-526141

  However, in the related technique shown in FIG. 10, since the hopping frequency switching time is high, a high-performance frequency synthesizer or filter is required to synchronize the hopping time, and a high-frequency amplifier circuit (hereinafter referred to as “RF circuit”). There is a problem that the scale and burden of display) increase.

  Further, since the hopping pattern is known, communication may not be established due to multi-spot interference or the like even if hopping is performed. Furthermore, when an unknown hopping pattern is used in order to improve the interference resistance, there is a problem that an RF circuit for capturing the unknown frequency hopping is further required.

  Further, in the related technique described in Patent Document 1, it is necessary to generate and synchronize the frequency code, and a high-speed frequency synthesizer for despreading is also required. There is a problem that the scale and the burden of the RF section increase.

  On the other hand, none of Patent Documents 2 to 4 describes means for solving the problem that the scale and the burden of the RF section are increased and it is difficult to improve the interference resistance.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a frequency hopping radio communication apparatus, a frequency hopping method thereof, a transmission apparatus and a reception apparatus that can reduce the scale and burden of an RF unit and can improve the interference resistance.

  In order to solve the above problems, a frequency hopping wireless communication apparatus according to the present invention receives a signal including a hopping pattern and a transmitting apparatus that transmits a reference information signal in an arbitrary frequency band and an arbitrary hopping pattern at regular intervals. And a receiving device that detects the frequency of the hopping signal using discrete Fourier transform and demodulates the frequency-detected hopping signal to obtain the reference information signal.

  The frequency hopping method of the frequency hopping wireless communication apparatus according to the present invention includes a transmission step of transmitting a reference information signal in an arbitrary frequency band and an arbitrary hopping pattern every predetermined time, and a signal including the hopping pattern, A receiving step of detecting the frequency of the hopping signal using discrete Fourier transform and demodulating the frequency-detected hopping signal to obtain the reference information signal.

  The frequency hopping wireless communication transmitting apparatus according to the present invention transmits a reference information signal in an arbitrary frequency band and an arbitrary hopping pattern at regular time intervals.

  In addition, the frequency hopping wireless communication receiver according to the present invention receives a reference information signal transmitted in an arbitrary frequency band and an arbitrary hopping pattern at regular time intervals, and uses the discrete Fourier transform to change the frequency of the hopping signal. The reference information signal is obtained by detecting and demodulating the frequency-detected hopping signal.

  According to the present invention, it is possible to reduce the scale and burden of the RF unit and increase the anti-jamming property.

It is a block diagram which shows the operating principle of the frequency hopping radio | wireless communication apparatus which concerns on this invention. It is a block diagram of an example of the frequency hopping radio | wireless communication apparatus which concerns on this invention. It is a schematic diagram of an example of the hopping pattern produced | generated by the frequency hopping part of the transmitter which concerns on this invention. 6 is a schematic diagram illustrating an example of the operation of a DFT unit 214. FIG. It is a flowchart which shows an example of operation | movement of the frequency hopping method which concerns on this invention. It is a flowchart which shows an example of operation | movement of the frequency hopping method which concerns on this invention. It is a block diagram of an example of the transmission apparatus of the frequency hopping radio | wireless communication apparatus which concerns on this invention. It is a block diagram of an example of the receiver of the frequency hopping radio | wireless communication apparatus which concerns on this invention. It is a schematic diagram which shows an example of the synchronization method of the hopping frequency in related technology. It is a schematic diagram which shows another example of the synchronization method of the hopping frequency in related technology.

  First, the operation principle of the present invention will be described before the description of the embodiment. FIG. 1 is a block diagram showing the operating principle of a frequency hopping wireless communication apparatus according to the present invention. Referring to FIG. 1, the frequency hopping wireless communication device 1 according to the present invention includes a transmission device 11 and a reception device 21.

  The transmission device 11 transmits the reference information signal in an arbitrary frequency band and an arbitrary hopping pattern at regular time intervals. The receiving device 21 receives a signal including a hopping pattern, performs discrete Fourier transform on the received signal to detect the frequency of the hopping signal, and demodulates the frequency-detected hopping signal to obtain a reference information signal.

  That is, according to the present invention, a signal transmitted from the transmission device 11 with the hopping pattern of the reference information signal being randomly changed within an arbitrary frequency band is received by the reception device 21, and the frequency is detected using discrete Fourier transform. Thus, since the reference information signal is obtained, it is possible to reduce the scale and burden of the RF unit and increase the anti-jamming property.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 2 is a configuration diagram of an example of a frequency hopping wireless communication apparatus according to the present invention. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  Referring to FIG. 2, the frequency hopping wireless communication device 1 according to the present invention includes a transmission device 11 and a reception device 21. Hereinafter, the reference information signal is indicated as “NTR signal” (NTR: Network Time Reference). In addition, the reference information signal may be displayed as a beacon signal.

  The transmission device 11 includes a modulation unit 111, a frequency hopping unit 112, and a power amplification unit 113.

  The receiving device 21 includes a high-frequency amplifier 211, a frequency converter 212, an AD (Analog to Digital) converter 213, a DFT (Discrete Fourier Transform) unit 214, and a demodulator 215.

  Next, an example of the operation of the transmission device 11 will be described. The NTR signal is modulated by the modulation unit 111. The modulated signal is frequency hopped by the frequency hopping unit 112. Then, the frequency hopped signal is power amplified by the power amplifying unit 113 to obtain a predetermined transmission signal.

  Next, an example of a hopping pattern generated by the frequency hopping unit 112 of the transmission device 11 will be described. FIG. 3 is a schematic diagram of an example of a hopping pattern generated by the frequency hopping unit of the transmission apparatus according to the present invention. In the figure, the vertical axis represents hopping frequency (Hz) and the horizontal axis represents time (sec.).

  Referring to the figure, the hopping frequency variable range of the NTR signal transmitted from the transmitter 11 is limited to an arbitrary frequency band. In the figure, the variable range of the hopping frequency of the NTR signal is limited to a certain frequency band (hereinafter referred to as “BW” (Band Width)) within the use frequency range. In the figure, an example in which BW is set to 10 MHz is shown.

  Then, the hopping pattern of the NTR signal is randomly changed and transmitted every NTR acquisition time period within the band. At this time, on the receiving device 21 side, the variable frequency pattern for each NTR acquisition time period of the BW from which the NTR signal is transmitted is known, and the hopping pattern in the BW is unknown.

  Next, an example of the operation of the receiving device 21 will be described. Returning to FIG. 2, the received high-frequency signal including the frequency hopping signal is amplified by the high-frequency amplifier 211 as necessary. Next, the high frequency amplified signal is converted to an intermediate frequency by the frequency converter 212. Next, the signal converted to the intermediate frequency is converted from an analog signal to a digital signal by the AD converter 213. Next, the digital signal is subjected to discrete Fourier transform by the DFT unit 214 to detect the frequency, and the demodulating unit 215 converts the frequency information to time information to obtain an NTR signal.

  Next, an example of a hopping signal capturing process in the receiving device 21 will be described. In the related art, it is possible to wait for and receive a signal in the frequency band transmitted from the transmission device 11, but it is unclear where the hopping signal exists in the frequency band, so an NTR signal cannot be obtained.

  Therefore, in the present invention, the frequency of the received signal is detected by the DFT unit 214 to detect a hopping signal within the NTR acquisition time, and the detection signal is converted from a parallel signal to a serial signal by the demodulation unit 215. Obtain the NTR signal.

  Here, an example of the operation of the DFT unit 214 of the receiving device 21 will be described. FIG. 4 is a schematic diagram illustrating an example of the operation of the DFT unit 214. In addition to the DFT unit 214, a demodulating unit (P / S unit) 215 and a control unit 216 (not shown in FIG. 3) are also shown in FIG.

  Referring to the figure, the received signal converted from an analog signal to a digital signal in AD converter 213 is input to DFT unit 214 for frequency detection. In the figure, an example is shown in which the DFT unit 214 separates the received signal into signals of frequencies f1 to fn (n is a positive integer). The signal separated into the frequencies f1 to fn is converted from a parallel signal to a serial signal by a demodulation unit (P / S unit) 215, whereby a time signal whose frequency information includes an NTR signal is output. The control unit 216 extracts only the NTR signal from this time signal.

  As described above, according to the frequency hopping wireless communication apparatus of the present invention, first, a small receiving apparatus can be configured at low cost. That is, since the RF frequency is constant within the NTR acquisition time, the hopping time can be easily managed, and the BW also has a wide band, so there is no need to provide a high-performance frequency synthesizer or filter, and a complicated synchronization algorithm is provided. Since it is not necessary, the RF circuit scale can be reduced.

  Second, since the hopping pattern can be arbitrarily changed on the transmission side, the anti-jamming property can be improved. That is, since the NTR signal is dispersed as a hopping signal within the 10 MHz band, even if a third party tries to interfere, the frequency band may be specified, but the hopping pattern is unknown and the influence of various interferences is reduced. There is an effect that can be.

  Next, the frequency hopping method of the frequency hopping wireless communication apparatus according to the present invention will be described. 5 and 6 are flowcharts showing an example of the operation of the frequency hopping method according to the present invention. FIG. 5 shows the operation of the transmission device 11, and FIG. 6 shows the operation of the reception device 21.

  Referring to FIG. 5, the modulation unit 11 of the transmission device 11 modulates the NTR signal (step S1). Next, the frequency hopping unit 112 converts the modulated signal into a signal that hops in an arbitrary frequency band and an arbitrary hopping pattern at regular time intervals (step S2). The power amplifying unit 113 amplifies the power of the hopping signal and transmits it (step S3).

  Referring to FIG. 6, the high frequency amplification unit 211 of the reception device 21 receives a signal including a hopping pattern and amplifies the high frequency (step S11). The frequency converter 212 converts the frequency of the high frequency amplified signal (step S12). The AD conversion unit 213 converts the analog signal after frequency conversion into a digital signal (step S13). The DFT unit 214 performs discrete Fourier transform on the digitally converted signal (step S14). The demodulator 215 demodulates the signal after the discrete Fourier transform (step S15).

  As described above, according to the frequency hopping method of the present invention, it is possible to obtain a frequency hopping method capable of configuring a small receiving device at low cost and improving the anti-jamming property.

  Next, the transmission apparatus according to the present invention will be described. FIG. 7 is a configuration diagram of an example of a transmission device of a frequency hopping wireless communication device according to the present invention. Referring to the figure, the configuration of the transmission device 31 is the same as that of the transmission device 11 included in the frequency hopping wireless communication device 1 of FIG. Therefore, the same numbers as those in FIG. Thus, the configuration of the transmission device 31 is the same as that of the transmission device 11, and therefore the operation is also the same as that of the transmission device 11. Therefore, the description of the configuration and operation is omitted.

  As described above, according to the transmission device 31 of the present invention, there is an effect that the interference resistance can be improved.

  Next, the receiving apparatus according to the present invention will be described. FIG. 8 is a configuration diagram of an example of a receiving device of the frequency hopping wireless communication device according to the present invention. Referring to the figure, the configuration of the receiving device 41 is the same as that of the receiving device 21 included in the frequency hopping wireless communication device 1 of FIG. Therefore, the same numbers as those in FIG. As described above, the configuration of the reception device 41 is the same as that of the reception device 21, and therefore the operation is also the same as that of the reception device 21.

  As described above, according to the receiving device 41 of the present invention, there is an effect that it is possible to configure a small receiving device at a low cost and to improve the interference resistance.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Supplementary note 1) The transmission step includes a modulation step for modulating a reference information signal, a frequency hopping step for frequency hopping the reference information signal, and a power amplification step for power amplifying the signal after frequency hopping. Frequency hopping method.

(Supplementary Note 2) The reception step includes a high frequency amplification step for receiving a signal including a hopping pattern and performing high frequency amplification, a frequency conversion step for performing frequency conversion on the high frequency amplified signal, and converting the analog signal after frequency conversion into a digital signal. Frequency hopping characterized by including an AD (Analog to Digital) conversion step, a DFT (Discrete Fourier Transform) step for discrete Fourier transform of the signal after digital conversion, and a demodulation step for demodulating the signal after the discrete Fourier transform Method.

(Supplementary note 3) Frequency hopping radio communication characterized in that the frequency bandwidth per fixed time at which the reference information signal is transmitted is 1 / n (n is an integer of 2 or more) of the hopping frequency variable bandwidth Transmitter device.

(Additional remark 4) The modulation part which modulates the said reference information signal, the frequency hopping part which carries out frequency hopping of the said reference information signal, and the power amplification part which carries out power amplification of the signal after frequency hopping are added. The transmitting device according to 1.

(Supplementary note 5) A frequency hopping wireless communication receiver characterized in that a frequency band pattern in which a reference information signal is transmitted at regular intervals is known on the receiver side.

(Supplementary note 6) The supplementary note 5 is characterized in that the frequency bandwidth for each fixed time in which the reference information signal is transmitted is 1 / n (n is an integer of 2 or more) of the hopping frequency variable bandwidth. Receiver.

(Supplementary note 7) A high-frequency amplification unit that receives a signal including a hopping pattern and amplifies it at a high frequency, a frequency conversion unit that converts the frequency of the high-frequency amplified signal, and an AD (Analog to) that converts the analog signal after frequency conversion into a digital signal Supplementary note 5 or 6, comprising: a (Digital) conversion unit, a DFT (Discrete Fourier Transform) unit that performs discrete Fourier transform on the signal after digital conversion, and a demodulation unit that demodulates the signal after discrete Fourier transform Receiver.

  The present invention can be applied to a receiver such as a software-defined radio that changes the radio frequency to be received.

DESCRIPTION OF SYMBOLS 1 Frequency hopping radio | wireless communication apparatus 11,31 Transmission apparatus 21,41 Reception apparatus 111 Modulation part 112 Frequency hopping part 113 Power amplification part 211 High frequency amplification part 212 Frequency conversion part 213 AD conversion part 214 DFT part 215 Demodulation part 216 Control part

Claims (10)

A transmission device that transmits a reference information signal in an arbitrary frequency band and an arbitrary hopping pattern at regular intervals;
A receiving device that receives a signal including a hopping pattern, performs discrete Fourier transform on the received signal to detect a frequency of the hopping signal, and demodulates the frequency-detected hopping signal to obtain the reference information signal. Frequency hopping wireless communication device.   2. The frequency hopping wireless communication apparatus according to claim 1, wherein a frequency band pattern in which the reference information signal is transmitted at regular intervals is known on the receiving apparatus side.   3. The frequency according to claim 1, wherein a frequency bandwidth for each predetermined time in which the reference information signal is transmitted is 1 / n (n is an integer of 2 or more) of a hopping frequency variable bandwidth. Hopping wireless communication device.   The transmission apparatus includes: a modulation unit that modulates the reference information signal; a frequency hopping unit that frequency hops the reference information signal; and a power amplification unit that amplifies the power of the signal after frequency hopping. Item 4. The frequency hopping wireless communication apparatus according to any one of Items 1 to 3.   The receiving apparatus receives a signal including a hopping pattern and amplifies the signal by high frequency, a frequency converter that converts the frequency of the amplified signal, and an AD (Analog) that converts the analog signal after the frequency conversion into a digital signal. 5. A to digital conversion unit, a DFT (Discrete Fourier Transform) unit that performs discrete Fourier transform on a signal after digital conversion, and a demodulation unit that demodulates the signal after discrete Fourier transform. The frequency hopping wireless communication apparatus according to any one of the above. A transmission step of transmitting a reference information signal at an arbitrary frequency band and an arbitrary hopping pattern at regular intervals;
Receiving a signal including a hopping pattern, performing discrete Fourier transform on the received signal to detect the frequency of the hopping signal, and demodulating the frequency-detected hopping signal to obtain the reference information signal. Frequency hopping method for a frequency hopping wireless communication device.   The frequency hopping method according to claim 6, wherein a frequency band pattern in which the reference information signal is transmitted at regular intervals is known on the receiving side.   8. The frequency according to claim 6, wherein a frequency bandwidth for each predetermined time in which the reference information signal is transmitted is 1 / n (n is an integer of 2 or more) of a hopping frequency variable bandwidth. Hopping method.   A frequency hopping wireless communication transmitting apparatus, wherein a reference information signal is transmitted in an arbitrary frequency band and an arbitrary hopping pattern at regular time intervals.   A reference information signal transmitted in an arbitrary frequency band and an arbitrary hopping pattern is received at regular time intervals, the received signal is subjected to discrete Fourier transform to detect the frequency of the hopping signal, and the frequency-detected hopping signal is demodulated. A frequency hopping radio communication receiver characterized in that the reference information signal is obtained.

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