JP2914759B2 - Wireless communication device and wireless communication system - Google Patents

Abstract

PURPOSE:To attain a quick shift between the analog and digital modes by holding the setting information on the transmission and reception channels obtained by an automatic frequency control function in an analog mode and forming a digital mode message channel based on the setting information. CONSTITUTION:The received RF signal is converted into a 1st intermediate frequency signal by a 1st mixer circuit 21. A control channel is first selected for reception of the control information sent from a base station. Then a paging channel is selected and the reception frequency is fixed by a reception PLL circuit 30. At the same time, the transmission frequency is set by a transmission PLL, circuit 30 in an analog mode. In this case, the control value of a voltage control crystal oscillation circuit 32 which was needed for convergence is held in a memory 40. Then a communication link using an access channel is formed to the base station with a calling request. If a digital mode is designated under such conditions, an AFC action is started based on the control value held in the memory 40.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called dual mode cellular radio system capable of performing communication in either an analog mode in which communication is performed by analog signals or a digital mode in which communication is performed by digital signals. Automatic frequency control of communication equipment (AFC:
Auto Frequency Control).

[0002]

2. Description of the Related Art Cellular wireless telephone devices have rapidly spread since their practical use. A conventional cellular radio telephone transmits and receives a call signal using an analog signal. In recent years, digital cellular radio telephones have been developed in addition to the conventional analog cellular radio telephones. During this transition from analog to digital, a dual-mode cellular radiotelephone that can communicate either in analog or digital form would be useful.

[0003] In the case of a digital cellular radiotelephone, frequency control is performed by AFC because more precise tuning is required for transmission and reception frequencies. In this case, AFC means that a transmission frequency is automatically set as a transmission frequency from a base station, that is, a frequency shifted by a predetermined frequency, for example, 45 MHz, based on a reception frequency from a mobile station.

In the above-described dual-mode cellular radio telephone, it is considered that control signals are exchanged between a mobile station and a base station through a control channel in a conventional analog system. In such a case, as a result of the exchange of the control signal, when the subsequent communication is set by the analog method, the communication link is set by the analog communication channel and the communication is performed by the digital method as before. When set, a call link is set by the digital call channel. Time division multiple access (TDMA) in digital communication channels
When the communication channel is set, the transmission frequency may be set by the above-mentioned AFC. The setting of the transmission frequency by the AFC is started, and after the transmission frequency is within a predetermined deviation, a call can be made.

[0005]

SUMMARY OF THE INVENTION Currently used
With AFC technology, it took a considerable amount of time for the frequency to converge within a given deviation. In particular, it takes a long time to converge the frequency where the received electric field intensity is small, and it takes a considerable time to converge even in the fading state. Voltage controlled oscillator (VCXO)
It is conceivable to shorten the time required for convergence by increasing the accuracy of the fundamental frequency by means of, but such a highly accurate VCXO becomes expensive and large, and goes against the downsizing and cost reduction of wireless communication devices. It will be.
Thus, according to currently considered dual mode cellular radiotelephones, switching to a digital mode call channel requires some time before the user can start a call.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dual mode cellular radiotelephone which can eliminate the above-mentioned problems and can quickly switch to a digital mode communication channel. [Configuration of the Invention]

[0007]

According to the present invention, there is provided a wireless communication apparatus comprising: a receiving means for receiving an electromagnetic wave signal arriving via a wireless line; and a receiving channel by tuning to a signal received by the receiving means. Channel setting means for setting, a predetermined frequency from the reception channel set by the reception channel setting means, a transmission channel setting means for setting a frequency channel separated from the reception channel as a transmission channel, via the set transmission channel And a transmission means for transmitting a signal to be transmitted. The automatic frequency control function includes a control signal communication link for transmitting and receiving a control signal by the automatic frequency control function. A control link is formed, and information relating to transmission and reception channel settings of the formed control link is held, and When the mode designation signal obtained via the signal communication link is an analog mode designation signal, an analog speech signal communication link for transmitting / receiving an analog speech signal is formed, and the mode designation signal is a digital mode designation signal. In the case of (1), a digital communication signal communication link for transmitting and receiving a digital communication signal is formed by an automatic frequency control function based on the information relating to the setting of the transmission and reception channels of the control signal communication link held in the holding means. .

According to another aspect of the present invention, there is provided a wireless communication apparatus comprising: a receiving unit for receiving an electromagnetic wave signal arriving via a wireless line; and a receiving channel set by tuning to the signal received by the receiving unit. Receiving channel setting means for performing transmission, a transmission channel setting means for setting a frequency channel separated from the receiving channel set by the receiving channel setting means at a predetermined frequency and a transmission channel as a transmission channel, and performing transmission via the set transmission channel. A transmission means for transmitting a signal to be provided, comprising an automatic frequency control function, forming a control signal communication link for transmitting and receiving control signals by this automatic frequency control function,
It holds information related to the setting of the transmission and reception channels of the control signal communication link formed by the control link forming means. Based on the held information related to the setting of the transmission and reception channels of the control signal communication link, automatic frequency control is performed. The control function forms a digital communication signal communication link for transmitting and receiving the digital communication signal.

[0009] A wireless communication apparatus according to still another aspect of the present invention includes a receiving means for receiving an electromagnetic wave signal arriving via a wireless line, and a receiving channel tuned to the signal received by the receiving means. Receiving channel setting means for setting, a transmission channel setting means for setting a frequency channel separated from the receiving channel set by the receiving channel setting means at a predetermined frequency as a transmission channel, and transmitting via the set transmission channel And a transmitting means for transmitting a signal to be transmitted. The automatic frequency control function forms a first communication link for transmitting and receiving signals, and Holds information related to the setting of the transmission and reception channels of the communication link, and the transmission and reception channels of the held communication link. The automatic frequency control function based on the information relating to the setting of the channel, the first communication link to form another second communication link.

[0010]

According to the present invention, a second communication link different from the first communication link is provided by an automatic frequency control function based on information relating to the setting of the transmission and reception channels of the first communication link already formed. Is formed. That is, when forming the second communication link, the link formation is started while maintaining the setting accuracy of the first communication link. Therefore, compared with the case where the second communication link is formed without being based on the information related to the setting of the transmission and reception channels of the first communication link, the transmission / reception frequency is more quickly converged within a predetermined frequency deviation, and Communication link can be established.

[0011]

FIG. 1 is a block diagram showing a dual mode cellular telephone according to an embodiment of the present invention. 1 is an antenna, 2 is a duplexer, 3 is a receiving circuit, 4 is a synthesizer circuit, 5 is a transmitting circuit, 6 is a modem circuit, 7 is a channel codec circuit, 8 is a speech codec, 9
Is a receiver, 10 is a transmitter, 11 is a voice switch, 12 is a voice switch, 13 is a control unit, 14 is a control circuit, 15
Is an analog audio signal processing circuit, 16 is a power supply circuit, 17
Is the power source (car battery).

FIG. 2 is a block diagram for explaining the AFC circuit. 21 is a first mixer circuit, 22 is a second mixer circuit, 23 is an IF amplifier, 24 is an FM discriminator circuit, 25
Is a modem circuit, 26 is a buffer amplifier, 27 is a buffer amplifier, 28 is a frequency multiplier circuit, 29 is a frequency counter circuit, 30
Is a reception PLL circuit, 31 is a transmission PLL circuit, 32 is a voltage controlled crystal oscillation circuit, 33 is a low-pass filter circuit, 34 is a D / A converter, 35 is a control circuit, and 36 is a buffer amplifier.

Transmission / reception of a radio wave signal is performed via the antenna 1. First, the operation in the digital mode will be described. A reception signal is input to the reception circuit 3 via the duplexer 2. Here, the received signal is mixed down with the local output of the synthesizer circuit 4 to be lowered to the IF frequency and input to the modem circuit 6. The modem circuit 6 demodulates the received signal into a digital signal, and the channel codec circuit 7 performs error correction. The digital signal is demodulated into a voice signal in the speech codec 8 and is generated as an acoustic output from the receiver 9 via the voice switch circuit 11. On the other hand, the audio signal output from the transmitter 10 is input to the speech codec circuit 8 via the audio switch 12 circuit. This speech signal is converted into a digital signal in the speech codec circuit 8 and error correction is performed in the channel codec circuit 7. The transmission signal subjected to the error correction is digitally modulated by the modem circuit 6 and sent to the transmission circuit 5 as an IF frequency signal. The transmitting circuit 5 is a synthesizer 4
The output of this is mixed with the transmission signal to obtain the transmission frequency,
The signal is amplified to the transmission output by the power amplifier, and the transmission signal is output from the antenna 1 via the duplexer 2. The control circuit 14 controls each section.

The input / output unit 13 includes a dial key, a display, and various switches, and exchanges control signals with the control circuit 14. Power circuit 16 is the car battery
The output of 17 is stabilized and supplied to each section.

Next, a configuration for a call in the analog mode will be described. Analog audio signal processing circuit
Numeral 15 is for processing data signals and audio signals.
The data signal is an FSK signal, which processes the digital signal from the control circuit and sends it to the transmission circuit. It also processes the data output from the receiving circuit and sends it to the control circuit. The audio signal is FM-demodulated by the receiving circuit 3 and FM-modulated by the transmitting circuit 5. The voice switches 11 and 12 are for switching between analog mode communication and digital mode communication. FIG. 2 is a block diagram illustrating the operation of the AFC.

The first mixer circuit 21 converts the received RF signal into a first intermediate frequency signal. Next, the second mixer circuit 22
Is converted to a second intermediate frequency signal. Then the IF amplifier
At 23, predetermined amplification is performed, and the result is input to the modem circuit 25. On the other hand, the second intermediate frequency signal is also inputted to an FM discriminator circuit 24 for FM demodulation, where it is FM demodulated and outputted to an analog audio signal processing circuit 15.

The frequency of the second intermediate frequency signal is counted by the frequency counter 29 using the output of the voltage controlled crystal oscillation circuit 32 as a time base. This count output is sent to the control circuit 35
And the corresponding digital signal is A / D
Output to converter 34. Here, it is converted into a DC analog signal corresponding to the level of the digital signal, and the LPF circuit 33
Removes the clock frequency of the D / A converter to make the DC stable and drives the VCXO32. The first local oscillation frequency is generated by the reception PLL circuit 30 using the output of the VCXO 32 as a reference frequency, and is input to the first mixer via the buffer amplifier 26.

The frequency of the VCXO output synchronized with the reception frequency can be obtained by the above-described loop. That is, automatic frequency control is performed. Send this VCXO output
If the reference frequency of the PLL 31 is used, it is possible to make the transmission frequency correspond to the reception frequency. Transmit PLL circuit 31
Is output to the transmission circuit 5 via the buffer amplifier 36. The second local oscillator multiplies the output of the VCXO 32 by a multiplying circuit 28, and outputs the same through a buffer amplifier 27 to a second mixer circuit 22.
Output to By setting the reference of the second local oscillator circuit to VCXO output in this way, the deviation of the second local oscillator can be ignored. The receiving frequency is 869.04-893.97MHz, the transmitting frequency is 824.04-848.97MH
Used for channel separation of 30KHz each at z. The frequency interval between transmission and reception is 45 MHz. It is specified by the system specifications that the deviation of the transmission frequency at the time of digital is (reception frequency -45 MHz) ± 200 Hz. It is digital modulation that demands such a severe frequency deviation.
(Π / 4 QPSK modulation).

FIG. 3 is a schematic sequence diagram for explaining the communication link setting performed between the base station (BS) and the mobile station (MS). First, initialization is performed, and the mobile station scans a predetermined number of control channels (C-ch) and selects one control channel having a strong reception electric field strength. Thus, the system information is updated by the communication link set using the control channel. Then, like the control channel,
Received paging channel (Pc) with strong received electric field strength
h) is selected. At this time, the paging channel (P
-Ch) is set. According to the system specifications, the transmission frequency deviation in the analog mode is allowed up to ± 1.5 ppm, and if a transmission paging channel that converges within this deviation is set, a paging channel communication link is formed. It will be. At this time, the control value for the reference oscillator required for convergence is held in the memory 40. The mobile station enters a standby state on this paging channel and waits for an incoming call or a call request from the user. For example, when a call request is made, a communication link using an access channel is formed with the base station. At this time, the access channel for transmission is set by AFC, and paging and
The control value for the reference oscillator held in the memory 40 when setting the channel is used. The access information is updated via a communication link formed by the access channel, and a call signal is transmitted from the mobile station to the base station. The call signal includes a signal indicating that the mobile device is a dual mode cellular telephone. In response to the call signal, a call response signal is returned from the base station to the mobile station. The call response signal includes a signal indicating whether the communication channel is set in the analog mode or the digital mode. analog·
When the mode is designated, the communication channel is set in the analog mode as in the conventional case. When the digital mode is designated, a control link to the reference oscillator held in the memory 40 at the time of setting the access channel is used to form a communication link using the communication channel.

FIGS. 4 and 5 are flowcharts showing characteristic portions of the operation of the mobile station according to the present embodiment. The flowchart shows an example of the operation from a call from a mobile station to a call. In the initial setting, the mobile station tunes the receiver to the control channel C-ch (step 40). The system information is received and updated from the base station on this C-ch (step 41). Next, the paging channel is set to (P-
ch) Set and scan the paging channel. Further, the mobile station enters a standby state on the paging channel having the strongest reception electric field (step 42). AFC operation is started on the received paging channel (step 43). The AFC operation is stopped when there is a call request from the user and the AFC digital output from the control circuit at this time is held in the memory 40 (step 45). The access channel (A-ch) is set, each access channel is scanned, and the access channel with the strongest reception electric field is supplemented (step 46), and the AFC operation is started (step 46).
47). The access information is updated via the communication link using the access channel (A-ch), and a call signal is transmitted via the access channel (step 4).
9). Next, a call response signal from the base station is received (step 50). These include analog mode or digital mode.
A signal that specifies which of the modes to use and a signal that specifies the speech channel are included. When the communication via the access channel ends, the AFC operation stops, and
The AFC control value is stored in the memory 40 (step 5
1). A call mode is determined (step 52), and if it is analog, a call on an analog call channel is started (step 53). If it is digital, the digital communication channel is set based on the AFC control value in the memory 40 (step 54). After moving to the digital communication channel, AF
C Start the operation (step 55), and establish TDMA slot synchronization (step 56). The transmission frequency converges within a predetermined deviation by the AFC (step 57), and when the transmission frequency becomes ± 200 Hz, a call is started (step 58).

The above-mentioned AFC control operation will be described by exemplifying a specific value. In the communication in the analog mode, the frequency of the received signal has an allowable deviation of ± 2.5 ppm, for example, 800 MHz ± 2 KH.
z, and the maximum deviation of the output frequency of the receiving PLL circuit 30 from the first local station is ± 5 ppm.
For example, since the maximum deviation of the output frequency of the multiplying circuit 28, which is 880 MHz ± 4.4 kHz and the second local oscillator, is ± 5 ppm, for example,
9.545 MHz plus or minus 400 Hz. Therefore, the frequency of the output of the IF amplifier 23 has the maximum deviation (2+
4.4 + 0.4) = 6.8 KHz. In the frequency counter circuit 29, the output signal of the IF amplifier 23 accompanied by this deviation is output from the voltage controlled crystal oscillation circuit 32.
And the number of punches is counted. This count value is compared with a punching count value corresponding to 455 KHz, which is an ideal carrier frequency of the output signal of the IF amplifier 23, and a digital value corresponding to the difference is output from the frequency counter circuit 29. If 1 Hz = 1 bit is associated, the output signal of the frequency counter circuit 29 is a 14-bit code signal which can represent the polarity and up to 6.8 KHz. Upon receiving this code signal, the control circuit 35 controls the D / A converter 34 so as to compensate for this deviation until it falls within the range of plus or minus one.
An 8-bit digital signal, which is an FC control value, is output. The D / A converter 34 converts this digital signal into 25
The DC signal is converted into a DC signal having six levels, and this DC signal is supplied to the voltage-controlled crystal oscillation circuit 32 as a control voltage. In this way, the reference frequency signal of the mobile station is fed back to synchronize with the received signal from the fixed station.
Holds the AFC control value at this time in the memory 40. As a result, the reception frequency is fixed, and the transmission frequency 45 MHz away from the reception frequency is automatically set by the transmission PLL circuit 31, and the frequency of the communication link between the fixed station and the mobile station is set. Becomes

As described above, by performing the AFC operation on the paging channel and the access channel, the AFC operation is performed in accordance with the base station frequency deviation in the analog mode and based on the AFC control blood of the same local area. Since the digital communication channel is set, the convergence time of the AFC operation in the digital communication channel can be shortened, so that a call can be made quickly. The specification of the base station is that the transmission frequency deviation for analog is ± 1.5 ppm and the transmission frequency deviation for digital is ± 0.25 ppm. Therefore, once the AF
If the C operation is performed and tuning is performed, the time for tuning in digital can be shortened.

When the mobile station moves and enters another zone, it is necessary to switch channels. This operation is generally called handoff. For dual mode machines, there is also a handoff from the analog talk channel to the digital talk channel. In this case, it is possible to shorten the AFC convergence time when switching to the digital communication channel by performing the same AFC operation as described above in the analog communication channel.

FIG. 6 is a flowchart for explaining the operation of the mobile station according to the embodiment in such a case. When the communication link is set by the analog mode communication channel (step 60), the AFC operation is performed (step 61). At this time, when the mobile station moves from one zone to another zone, a handoff command is transmitted from the base station to the mobile station. This handoff command includes the next call channel to switch to and the
Contains a signal that specifies the mode or digital mode. When the mobile station receives this handoff command, AF
The C operation is stopped, and the AFC control value at that time is held in the memory 40 (step 63). Next, the mobile station shifts to the designated communication channel (step 64), and starts the AFC operation based on the AFC control value held in the memory 40 (step 65). When the slot synchronization is established (step 66) and the transmission frequency converges (step 67), the call starts (step 68).

As described above, the AFC operation is performed at the time of receiving an analog data signal on the paging channel and the access channel or at the reception frequency of the analog communication channel, and is synchronized to a level corresponding to the frequency deviation of the base station ± 1.5 ppm. In this case, when a shift is made to the digital communication channel, there is an advantage that the frequency deviation required for the digital communication can be quickly tuned. Therefore, there is an advantage that a call can be made in a short time. Also, since a VCXO with particularly high frequency accuracy is not required, there is an advantage that an inexpensive and small wireless communication device can be supplied.

[0026]

According to the present invention, an automatic frequency control function based on information relating to the setting of the transmission and reception channels of the first communication link that has already been formed is used to separate the first communication link from the first communication link. Two communication links are formed,
At the time of forming the second communication link, the link formation is started while maintaining the setting accuracy of the first communication link, so that it is not based on information relating to the setting of the transmission and reception channels of the first communication link. As compared with the case where the second communication link is formed, the transmission / reception frequency can be more quickly converged within the predetermined frequency deviation to establish the second communication link.

[Brief description of the drawings]

FIG. 1 is a block diagram of a wireless communication device according to one embodiment of the present invention.

FIG. 2 is a block diagram for explaining the operation of the AFC circuit of the wireless communication device according to one embodiment of the present invention.

FIG. 3 is a sequence schematic diagram for explaining communication link setting performed between a base station and a mobile station.

FIG. 4 is a flowchart showing a characteristic portion of the operation of the mobile station according to the embodiment.

FIG. 5 is a flowchart showing a characteristic portion of the operation of the mobile station according to the embodiment.

FIG. 6 is a flowchart for explaining an operation of the mobile station according to the embodiment in the case of a handoff operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Antenna, 2 ... Duplexer, 3 ... Receiving circuit, 4 ... Synthesizer circuit, 5 ... Transmitting circuit, 6 ... Modem circuit, 7 ... Channel codec circuit, 8 ... Speech codec circuit,
9 ... handset, 10 ... transmitter, 11 ... voice switch, 12 ... voice switch, 13 ... control unit, 14 ... control circuit,
15… Analog audio signal processing circuit, 16… Power supply circuit,
17 power supply, 21 first mixer circuit, 22 second mixer circuit, 23 IF amplifier, 24 FM discriminator circuit, 25
... modem circuit, 26 ... buffer amplifier, 27 ... buffer amplifier, 28 ... multiplier circuit, 29 ... frequency counter circuit, 30 ... receive PLL circuit, 31 ... transmit PLL circuit, 32 ... voltage controlled crystal oscillator circuit (VCXO), 33 ... D-pass filter circuit, 34 ... D / A converter, 35 ... Control circuit, 36 ... Buffer amplifier

Claims (10)

(57) [Claims] A receiving means for receiving an electromagnetic wave signal arriving via a wireless line; a receiving channel setting means for setting a receiving channel by tuning to a signal received by the receiving means; A predetermined frequency from the reception channel set by the reception channel setting means,
A radio having an automatic frequency control function including transmission channel setting means for setting a separated frequency channel as a transmission channel, and transmission means for transmitting a signal to be transmitted via the set transmission channel A communication device, comprising: a control link forming means for forming a control signal communication link for transmitting and receiving a control signal by the automatic frequency control function; and a transmission of the control signal communication link formed by the control link forming means. And holding means for holding information related to the setting of the reception channel, and for transmitting and receiving an analog call signal when the mode designation signal obtained via the control signal communication link is an analog mode designation signal. Forming an analog call signal communication link, wherein said mode designating signal is a digital mode designating signal; The automatic frequency control function is used to form a digital communication signal communication link for transmitting and receiving a digital communication signal based on information relating to the setting of the transmission and reception channels of the control signal communication link held in the holding means. A wireless communication device comprising: a communication link forming unit. 2. The radio communication apparatus according to claim 1, wherein said holding means is frequency control information indicating a deviation of a frequency of a received signal from a predetermined frequency. 3. A receiving means for receiving an electromagnetic wave signal arriving via a wireless line, a receiving channel setting means for setting a receiving channel by tuning to a signal received by the receiving means, A predetermined frequency from the reception channel set by the reception channel setting means,
A radio having an automatic frequency control function including transmission channel setting means for setting a separated frequency channel as a transmission channel, and transmission means for transmitting a signal to be transmitted via the set transmission channel A communication device, comprising: a control link forming means for forming a control signal communication link for transmitting and receiving a control signal by the automatic frequency control function; and a transmission of the control signal communication link formed by the control link forming means. And holding means for holding information related to the setting of the reception channel, and the automatic frequency control function based on the information related to the setting of the transmission and reception channels of the control signal communication link held in the holding means. Communication link forming means for forming a digital communication signal communication link for transmitting and receiving signals Radio communication apparatus characterized by equipped and. 4. The wireless communication apparatus according to claim 3, wherein said holding means is frequency control information indicating a deviation of a frequency of a received signal from a predetermined frequency. 5. A receiving means for receiving an electromagnetic wave signal arriving via a wireless line, a receiving channel setting means for setting a receiving channel by tuning to a signal received by the receiving means, A predetermined frequency from the reception channel set by the reception channel setting means,
A radio having an automatic frequency control function including transmission channel setting means for setting a separated frequency channel as a transmission channel, and transmission means for transmitting a signal to be transmitted via the set transmission channel A communication device, comprising: a communication link forming means for forming a first communication link for transmitting and receiving signals by the automatic frequency control function; and a transmission and reception channel of the communication link formed by the communication link forming means. Holding means for holding information relating to the setting of the first communication link, the automatic frequency control function based on the information related to the setting of the transmission and reception channels of the communication link held in the holding means, A communication link forming means for forming another second communication link. 6. The radio communication apparatus according to claim 5, wherein said holding means is frequency control information indicating a deviation of a frequency of a received signal from a predetermined frequency. 7. The first communication link is an analog communication signal communication link for transmitting and receiving an analog communication signal, and the second communication link is a digital communication signal communication link for transmitting and receiving a digital communication signal. The wireless communication device according to claim 5, wherein 8. The first communication link is a digital communication signal communication link for transmitting and receiving a digital communication signal, and the second communication link is an analog communication signal communication link for transmitting and receiving an analog communication signal. The wireless communication device according to claim 5, wherein 9. A receiving means for receiving an electromagnetic wave signal arriving via a wireless line, a receiving channel setting means for setting a receiving channel by tuning to a signal received by the receiving means, A transmission channel setting means for setting a frequency channel separated from the reception channel set by the reception channel setting means at a predetermined frequency as a transmission channel; and a transmission means for transmitting a signal to be transmitted via the set transmission channel. A wireless communication device having an automatic frequency control function including: a first communication link for transmitting and receiving signals by the automatic frequency control function;
Holding the information related to the setting of the transmission and reception channels of the communication link, and the first communication link by the automatic frequency control function based on the held information related to the setting of the transmission and reception channels of the communication link. Forming a second communication link separate from the wireless communication system. 10. The method according to claim 1, wherein the step of storing the information related to the setting of the transmission and reception channels of the communication link includes the step of storing frequency control information indicating a deviation of the frequency of the received signal from a predetermined frequency. Item 10. The wireless communication method according to item 9.