KR20050090119A - Method and system for frequency hopping radio communication - Google Patents

Abstract

A transmitter inputs an IF band modulation signal generated from transmission data and a frequency hopping signal acquired by a hopping synthesizer controlled by a hopping pattern generator to a mixer to acquire a radio signal with a hoping frequency and to transmit it. A receiver inputs an amplified reception signal from which the unwanted wave is removed and an output signal from the hopping synthesizer controlled by a signal produced by adding a fixed frequency offset signal to a hopping pattern generator to the mixer, downconverts the input signal to an unhopping IF band corresponding to the offset signal while maintaining the relative spectral relationship of the signal in the radio frequency band and acquires required data by demodulating an IF band modulation signal regenerated through unwanted wave removal and square-law detection.

Description

Method and system for frequency hopping radio communication

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frequency hopping wireless communication method and system in the case of performing wireless communication using a frequency hopping scheme in a very high frequency region such as millimeter wave.

When constructing a wireless communication system operating in a frequency band that does not require a license, the use of the frequency hopping method is effective as a means for avoiding or sufficiently suppressing the influence of narrowband interference.

6 and 7 show the configuration of a transmitter and a receiver of a wireless communication system in the case of using a general frequency hopping scheme. The transmitter inputs a signal obtained from the intermediate frequency (IF) to the modulator 1 into which the transmission data is input and the output of the hopping synthesizer 3 controlled by the signal from the hopping pattern generator 2 to the mixer 4, Obtain a frequency-hopped radio modulated signal. This is transmitted from the transmitting antenna 6 after the unwanted wave component is removed by the band filter 5. On the other hand, in the receiver, the received signal is received at the receiving antenna 7 and amplified by the amplifier 8, and then unwanted wave components are removed from the wideband bandpass filter 9, corresponding to this signal and the required received signal. The output signal of the hopping synthesizer 12 controlled by the hopping pattern generator 11 which generates a frequency hopping pattern is input to the mixer 10, which passes through the bandpass filter 13, of any fixed IF frequency that does not hopping. Obtain the modulated signal. This signal is input to the IF band demodulator 14 to demodulate the data. 7 also shows a configuration for capturing the synchronization of the hopping frequency in the receiver. That is, the output of the bandpass filter 13 also passes through a signal detector (envelope detection) 15 and an integrator 16, which is compared with a threshold level in a threshold comparator 17 so that the phase controller 18 ) And the output phase of the hopping synthesizer 12 is also controlled by the output.

In this case, in order to maintain the quality of the transmitted signal and to obtain an interference suppression effect by sufficient frequency hopping, the hopping synthesizer output used by the transmitter and the hopping synthesizer output used by the receiver are always a predetermined frequency difference. Therefore, it is required that the time variation of the phase difference is small. For this reason, the hopping synthesizer used in the transceiver is required to be excellent in frequency stability, low in phase noise, and to respond at high speed. In particular, in the region of high frequency microwave, studies are made such as stabilization and low noise by a dielectric resonator or a phase lock loop (PLL) circuit.

However, accompanied by a very high use frequency (for example, a millimeter wave of 30 GHz or more), it becomes difficult to realize a hopping synthesizer of low phase noise with high frequency stability, and at the same time, its manufacturing cost increases. When the modulated signal to be transmitted is a multicarrier signal that is a narrowband modulated signal or an Orthogonal Frequency Division Multiplexing (OFDM) signal, the hopping synthesizer in the transmission and reception period is required to be very accurate and frequency synchronized. In addition, since the frequency changes burst, it is necessary to respond to it at high speed. However, the implementation of a hopping synthesizer capable of frequency synchronization with such a high precision is usually very difficult at high frequencies such as millisecond bands, and when a large frequency offset is generated, it is immediately responded to or synchronized with it. It is difficult to solve the problem, and the solution has a problem of having a system having a very expensive stabilization mechanism.

1 is a diagram showing a first embodiment.

Fig. 2 is a diagram showing a spectrum transmitted and received in the first embodiment.

Fig. 3 is a diagram showing the configuration of a transmitter in the second embodiment.

Fig. 4 is a diagram showing the configuration of a receiver in the second embodiment.

Fig. 5 is a diagram showing spectrums transmitted and received in the second embodiment.

Fig. 6 is a diagram showing the configuration of a conventional frequency hopping transmitter.

Fig. 7 is a diagram showing the configuration of a conventional frequency hopping receiver.

The present invention has been made in view of the above circumstances, and an object thereof is to construct a frequency hopping wireless system that is not affected by frequency instability of a local oscillator or hopping synthesizer for frequency conversion.

In addition, the present invention enables the application of the frequency hopping method in a very high frequency region such as the millimeter wave, which is difficult to apply the frequency hopping method, and does not require a high definition as a local oscillator or hopping synthesizer to be used at that time. It aims to build a small terminal and system at low cost.

According to the present invention, a frequency hopping wireless communication method and system includes a transmitter for generating a radio modulated signal by multiplying an intermediate frequency band modulated signal from an intermediate frequency band modulation and demodulation unit with a local oscillation signal, and a local oscillation signal over a radio modulated signal. A down-converted intermediate frequency band demodulation signal is generated, and communication is performed between a plurality of radio communication terminals each having a receiving unit for demodulating in the intermediate frequency band modulation / demodulation unit. A transmission station for transmitting only a reference local oscillation signal is provided, or one of a plurality of radio communication terminals becomes a base station or a parent station, and uses a local oscillation signal used by the local station as a radio modulation signal. Send with Each of the plurality of radio communication terminals modulates the transmitted signal and demodulates the received signal using the frequency hopping method in the intermediate frequency band modulation / demodulation unit. In addition, the plurality of wireless communication terminals each receive a reference local oscillation signal from a transmitting station, amplify and band filter it, and then reproduce the reference local oscillation signal by an injection synchronous oscillator or amplifier, and transmits it to the transmission function and reception. They are used as local oscillation signals used as functions to communicate with each other.

In addition, in the present invention, in each of the plurality of wireless communication terminals, the transmitting unit up-converts the modulated signal generated in the intermediate frequency band to the radio frequency with a local oscillation signal functioning as a hopping synthesizer, and thus obtains a single side wave or a double side wave. The frequency hopping radio modulation signal and the local oscillation signal used for the upconversion are simultaneously transmitted. The receiver downconverts the received signal into a first intermediate frequency signal using a local oscillating signal frequency hopping in a pattern in which a fixed frequency offset is added to a frequency hopping pattern corresponding to a desired reception wave, and then downconverts it by passing it through a bandpass filter. Two signal components of the localized oscillation signal component and the modulated signal component are extracted, and the second intermediate frequency band modulated signal required by generating the product component of these two signal components is reproduced.

(First embodiment)

FIG. 1 shows a configuration of a wireless communication system showing a first embodiment of the present invention, and FIG. 2 shows a state of change in the signal spectrum transmitted and received by each station. As shown in Fig. 1C, one reference signal station 19 and a plurality of terminal stations 23 are constituted. As shown in FIG. 1B, the reference signal station 19 amplifies the reference local oscillation signal generated by the reference local oscillator 20 in the amplifier 21, and radiates from the antenna 22 to the service zone. Each terminal station 23 receives this at the reception antenna 24, as shown in Fig. 1A. The received signal is amplified by the amplifier 25 and then a portion thereof is branched off, and unwanted waves are removed by the band filter 26, which is input to the injection synchronous oscillator or amplifier 27. As a result, a local oscillation signal synchronized with the reference local oscillation signal generated from the reference signal station 19 is obtained. The terminal station 23 divides the obtained local oscillation signal into two, inputs one to the receiving frequency converter (mixer) 28 and the other to the transmitting frequency converter (mixer) 29. In addition, the mixers 28 and 29 of the terminal station 23 are connected to the intermediate frequency IF band modulation / demodulation circuit 31 of the FH method that demodulates and generates a signal of the frequency hopping method FH, respectively. The IF band FH modulated signal, which is the output of the subband, is input to the intermediate frequency band IF band modulation demodulation circuit 31 of the FH method after the unwanted wave component is removed by the band filter 30 to obtain required data. On the other hand, the IF-to-FH modulated signal obtained from the intermediate frequency (IF) -to-modulation / demodulation circuit 31 of the FH method is input to the mixer 29, frequency-converted to the radio frequency, and unwanted waves by the band filter 32. After is removed, the signal is amplified by the amplifier 33 and sent out from the transmitting antenna 34.

In addition, the configuration itself of the transceiver included in the IF band modulation / demodulation circuit 31 of the FH method is the same as that of the conventional frequency hopping system shown in Figs. According to this first embodiment, since the frequency offset and phase noise generated in the radio signal are sufficiently removed by the circuit before inputting to the IF band modulation / demodulation circuit 31 of the FH method, the IF band modulation / demodulation of the subsequent FH method is performed. Since the circuit 31 is not required to have a very fast response speed or excellent synchronization replenishment capability, a conventional frequency hopping circuit can be used.

In addition, Fig. 2 shows the state of change with respect to the time of the signal spectrum transmitted and received in the first embodiment. The spectrum (dark black portion) always transmitted from the reference signal station 19 is a radio modulated signal (faint black portion) that is upconverted and transmitted using this reference local oscillation signal while its frequency does not transition with time. Is frequency hopping at the same time.

In the first embodiment, a station transmitting only the reference local oscillation signal is provided separately from the terminal. However, in this configuration, in the case of a system in which the transmission aerial power per transmission station is limited, more transmission power is used as the reference local oscillation signal. Since it is assigned to, it is possible to increase the communication area.

However, the reference local oscillation signal transmitting station may also have a terminal function or a function of transmitting and receiving a signal. That is, any one of the terminal groups becomes a parent station and transmits a local oscillation signal used by the same station to the space as a reference local oscillation signal, and each of the other radio terminals receives the reference oscillation signal and amplifies and filters the band. Thereafter, the local oscillation signal synchronized with the reference local oscillation signal of a suitable level can be reproduced by the injection synchronous oscillator, and this can be used as a local oscillation signal for frequency conversion using the transmission / reception function.

In any case, in the first embodiment, by configuring the reference local oscillation signal, the configuration is not affected by the frequency instability of the local oscillator for frequency conversion. This makes it possible to construct a frequency hopping wireless system that is not affected by the frequency instability of the local oscillator for frequency conversion.

(Second embodiment)

3 and 4 illustrate a transmitter configuration and a receiver configuration of a wireless communication system according to a second embodiment of the present invention, and FIG. 5 illustrates a state of change of a signal spectrum transmitted and received between terminals at this time. The present invention can be applied to communication between a plurality of radio terminals, and each radio terminal is provided with a transmitter having the configuration of FIG. 3 and a receiver having the form of FIG. 4, thereby enabling bidirectional communication.

The transmitter illustrated in FIG. 3 uses the IF band modulator 35 to generate the IF band modulated signal, and the FH signal obtained from the hopping synthesizer 38 controlled by the hopping pattern generator 37 and the IF band. By inputting the modulated signal to the mixer 36, a radio signal hopping in frequency is obtained. This output usually includes the output signal of a hopping synthesizer used as a local oscillation signal in addition to the radio signals of the frequency-converted bilateral band waves as shown in FIG. These signals are amplified by the amplifier 39 and then transmitted from the antenna 40.

In the case of transmitting both side-wave signals and local oscillation signals at the mixer output as in the present embodiment, there is basically no need to remove them with a band filter, so as shown in FIG. The band frequency becomes unnecessary, which enables a low cost transmitter configuration.

In addition, when an image rejection type is used as the mixer, it is also possible to obtain an output signal of a hopping synthesizer used as a radio frequency signal and a local oscillation signal of a frequency-converted single side wave.

On the other hand, in the receiver, the signal received by the reception antenna 41 is amplified by the amplifier 42 and unwanted waves are removed by the band filter 43 and input to the mixer 44. In addition, the mixer 44 receives the output signal of the hopping synthesizer 47 controlled by the hopping pattern generator 45 as a signal to which the fixed frequency offset signal is added by the offset signal generator 46. As a result, the mixer 44 At the output of the signal of the radio frequency band downconverted to the first non-frequency hopping IF signal corresponding to the offset signal while maintaining its relative spectral relationship. When this is removed from the band filter 48, the unwanted wave is square-detected in the power generator 49, and the modulated signal in the intermediate frequency band used at the transmission source is reproduced. In this signal, the frequency offset and the degradation of the phase noise accompanying the up-convert and down-convert in the millimeter wave band in the FH method do not occur in principle. This is because the original local oscillating signal component downconverted to IF and the radio modulated signal component input to the square have the same frequency offset and phase noise components, which are canceled by the square detection. Therefore, by inputting the obtained IF band signal to the IF band demodulator 50, the required received data can be obtained. 4 also shows a configuration for capturing the synchronization of the hopping frequency in the receiver. That is, the output of the square 49 also passes through a signal detector (envelope detection) 51 and integrator 52, which is compared with a threshold level in the threshold comparator 53 and input to the phase controller 54. The output phase of the hopping synthesizer 47 is also controlled by the output.

 As described above, in the second embodiment, it is possible to construct a frequency hopping wireless system that is not affected by the frequency instability of the hopping synthesizer.

According to the present invention, it is possible to construct a frequency hopping wireless system that is not influenced by the frequency instability of a local oscillator or hopping synthesizer for frequency conversion, and very high frequencies such as millimeter waves, which has not been easily applied until now. Frequency hopping can be applied in the domain. In addition, since it is necessary to have a high-stability as a local oscillator or hopping synthesizer to be used at that time, it is possible to construct a small terminal and system at a low cost.

Claims (8)

Generating a downconverted intermediate frequency band demodulation signal by multiplying a local oscillation signal to a radio modulation signal by transmitting the intermediate frequency band modulation signal from the intermediate frequency band modulation and demodulation unit with a local oscillation signal, and a local oscillation signal to the radio modulation signal, In the radio communication method of performing communication between a plurality of radio communication terminals each having a receiver to demodulate in the demodulation unit, One transmitting station transmits a reference local oscillation signal, Each of the plurality of wireless communication terminals modulates a transmission signal and demodulates a reception signal using a frequency hopping method in the intermediate frequency band modulation / demodulation unit. Each of the plurality of wireless communication terminals receives the reference local oscillation signal from the transmitting station, amplifies and band filters it, and reproduces the reference local oscillation signal by an injection synchronous oscillator or amplifier, and transmits the reference local oscillation signal. A method of frequency hopping wireless communication, characterized in that it communicates with each other using a local oscillation signal used as a reception function. 2. The method of claim 1, wherein one transmitting station for transmitting only the reference local oscillating signal is provided. The radio station according to claim 1, wherein one of the plurality of radio communication terminals becomes a base station or a parent station, and transmits a local oscillation signal used in the own station together with the radio modulation signal, thereby becoming another radio station. Wherein each of the communication terminals receives a reference local oscillation signal transmitted by the base station or a parent station. Generating a downconverted intermediate frequency band demodulation signal by multiplying a local oscillation signal to a radio modulation signal by transmitting the intermediate frequency band modulation signal from the intermediate frequency band modulation and demodulation unit with a local oscillation signal, and a local oscillation signal to the radio modulation signal, A wireless communication method for performing communication between a plurality of wireless communication terminals each having a receiving unit demodulated by a modulation / demodulation unit, In each of the plurality of wireless communication terminals, the transmitting section up-converts the modulated signal generated in the intermediate frequency band to the local oscillation signal functioning as a hopping synthesizer at the radio frequency, and thus the frequency of the single side wave or the double side wave obtained thereby. Simultaneously transmits a hopping radio modulation signal and a local oscillation signal used for the upconversion, The receiver downconverts the received signal into a first intermediate frequency signal with a local oscillating signal frequency hopping in a pattern in which a fixed frequency offset is added to a frequency hopping pattern corresponding to a desired reception wave, and then down-converts it by passing it through a bandpass filter. Frequency hopping, characterized in that it extracts two signal components of the converted local oscillating signal component and the modulated signal component and reproduces the second intermediate frequency band modulated signal required by generating a multiplicative component of the two signal components. Wireless communication method. Generating a downconverted intermediate frequency band demodulation signal by multiplying a local oscillation signal to a radio modulation signal by transmitting the intermediate frequency band modulation signal from the intermediate frequency band modulation and demodulation unit with a local oscillation signal, and a local oscillation signal to the radio modulation signal, A wireless communication system for performing communication between a plurality of wireless communication terminals each having a receiving unit demodulating in a demodulation unit, 1 transmitting station for transmitting a reference local oscillation signal, The intermediate frequency band demodulation unit is constituted by an intermediate frequency band modulation and demodulation device of a frequency hopping method, modulates a transmission signal and demodulates a reception signal. Each of the plurality of wireless communication terminals receives the reference local oscillation signal from the transmitting station, amplifies and band-filters it, and then reproduces the reference local oscillation signal by an injection synchronization oscillator or amplifier, and transmits the reference local oscillation signal. A frequency hopping wireless communication system, characterized in that it communicates with each other using as a local oscillation signal to be used as a reception function. 6. The frequency hopping radio communication system according to claim 5, wherein one transmitting station for transmitting only the reference local oscillation signal is provided. 6. The other radio communication apparatus according to claim 5, wherein one of the plurality of radio communication terminals becomes a base station or a parent station and transmits a local oscillation signal to be used in a local station together with a radio modulation signal, thereby becoming another radio station. And each of the communication terminals receives a reference local oscillation signal transmitted by the base station or the parent station. Generating a downconverted intermediate frequency band demodulation signal by multiplying a local oscillation signal to a radio modulation signal by transmitting the intermediate frequency band modulation signal from the intermediate frequency band modulation and demodulation unit with a local oscillation signal, and a local oscillation signal to the radio modulation signal, A wireless communication system for performing communication between a plurality of wireless communication terminals each having a receiving unit demodulated by a modulation / demodulation unit, In each of the plurality of radio communication terminals, the transmitting section up-converts the modulated signal generated in the intermediate frequency band to the radio frequency with a local oscillation signal functioning as a hopping synthesizer, thereby obtaining a frequency hopping radio frequency of a single side wave or a double side wave. Simultaneously transmit a modulation signal and a local oscillation signal used for the upconversion, The receiver downconverts the received signal into a first intermediate frequency signal with a local oscillating signal frequency hopping in a pattern in which a fixed frequency offset is added to a frequency hopping pattern corresponding to a desired reception wave, and then down-converts it by passing it through a bandpass filter. Frequency hopping, characterized in that it extracts two signal components of the converted local oscillating signal component and the modulated signal component and reproduces the second intermediate frequency band modulated signal required by generating a multiplicative component of the two signal components. Wireless communication system.