JP4407660B2 - Wireless communication system, wireless communication method, and communication control apparatus - Google Patents

Description

  The present invention relates to a radio communication system having two radio communication systems with different communication methods, and frequency bands used in each radio communication system overlapping each other, and a radio communication method used in the radio communication system.

  In recent years, various wireless communication systems for wirelessly connecting electronic devices at relatively short distances have been developed. For example, IEEE802.11b / g typified by wireless LAN, Bluetooth used in short-range communication, and the like are examples.

  Among them, IEEE802.11b uses a direct spread spectrum (DSSS) modulation scheme, and IEEE802.11g uses an orthogonal frequency division multiplexing (OFDM) modulation scheme. In Bluetooth, a modulation method using frequency hopping spread spectrum (FHSS) is used. This FHSS system is also used for wireless communication (transmission / reception of audio signals, various control signals, etc.) between a parent device and a child device in a cordless telephone apparatus that has been digitized in recent years.

With the recent practical application and spread of short-range wireless communication, there have been cases where a plurality of wireless communication systems using the above-described communication methods (modulation methods) exist in the same area. For example, there is a case where a wireless LAN and a cordless telephone device or a wireless LAN and Bluetooth are used in the same room in a home (see, for example, Patent Document 1).
JP 2002-198867 A

  However, since each of the communication methods uses a 2.4 GHz band frequency band called an ISM band (Industry Science Medical band), a plurality of wireless communication systems using the communication methods are in the same area. If they exist, the radio waves interfere with each other between different wireless communication systems, and there is a problem in that the communication performance of both of them deteriorates.

  That is, for example, in the wireless LAN of IEEE802.11b, the 2.4 GHz band is divided into 14 channels (the bandwidth of one channel is approximately 25 MHz), and wireless communication is performed using one of these channels. On the other hand, in the cordless telephone device using the FHSS system, the 2.4 GHz band is divided into, for example, 89 channels (the bandwidth of one channel is about 1 MHz), and every extremely short time (about 0.1 second). Wireless communication is performed while changing (hopping) the use channel. Therefore, if both exist in the same area, when the channel hopped in the FHSS system overlaps the band of the channel being used in the wireless LAN, they interfere with each other.

  In recent years, as represented by so-called multifunction devices, devices having both a network (LAN) function and a cordless telephone function are becoming widespread, and a multifunction device having both a wireless LAN function and a digital cordless function is configured. When trying to do so, the DSSS wireless LAN module and the FHSS digital cordless telephone module are present in the same casing, so the above problem (radio wave interference) becomes significant.

  In order to solve this problem, Patent Document 1 described above measures the bit error rate (BER) of each channel in each communication method when the wireless LAN and the Bluetooth are used in the same area. A technique is described in which the channel is not used if radio interference occurs with another communication system (that is, BER is equal to or higher than a predetermined reference value).

  However, with the above method, both the wireless LAN and Bluetooth search for each channel (BER detection) over the entire 2.4 GHz band (all channels) and determine whether or not the channel can be used. Therefore, the processing load increases on both sides. Especially when a plurality of wireless communication systems coexist in the same housing, such as a multifunction device, the processing load of BER detection processing for each channel adversely affects other processing (other functions). There is also a fear.

  The present invention has been made in view of the above problems, and even when there are a plurality of wireless communication systems having overlapping usable frequency bands in the same area, radio interference between the wireless communication systems can be simplified. And it aims at preventing efficiently.

  The wireless communication system according to claim 1, which has been made to solve the above-described problem, includes a first wireless communication system and a second wireless communication system having different communication methods. The first wireless communication system includes a first communication control unit and a first communication device capable of wirelessly communicating with the first communication control unit using a predetermined first communication method. The second wireless communication system includes a second communication device capable of wirelessly communicating with the second communication control unit using a second communication control unit and a second communication method different from the first communication method. And the 1st frequency band used by the wireless communication in a 1st wireless communication system and the 2nd frequency band used by the wireless communication in a 2nd wireless communication system overlap.

Then, the first communication device performs the first communication control by using any one of the plurality of frequency channels in the first frequency band as channel information indicating a frequency channel used in the wireless communication of the first wireless communication system. A transmission means for transmitting to the means is provided. The first communication control means includes receiving means for receiving channel information transmitted from the first communication apparatus, and wireless communication with the first communication apparatus based on the channel information received by the receiving means. that is configured for setting the frequency channel to be used in. Further, the second communication control means includes one or more of the plurality of frequency channels in the second frequency band that are not included in the frequency band occupied by the frequency channel indicated by the channel information received by the receiving means. Channel setting means for setting the frequency channel to be the frequency channel used in the wireless communication of the second wireless communication system.

  In the wireless communication system configured as described above, although the communication method is different between the first wireless communication system and the second wireless communication, the use frequency bands are overlapped. Therefore, a specific frequency channel of the first frequency band is used for communication in the first wireless communication system, and a specific frequency channel of the second frequency band is also used for communication in the second wireless communication system. In such a case, the channels used in each system may overlap each other and cause radio wave interference with each other.

  Therefore, in the first wireless communication system, when any one frequency channel in the first frequency band is used in wireless communication, the first communication device uses the frequency channel used by the first communication control means. Is transmitted to the first communication control means. In the second radio communication system, the second radio communication system is configured so that the frequency channel used in the first radio communication system is not included based on the channel information received by the first communication control unit. Set the frequency channel used in. Specifically, one or a plurality of channels that are not included in the frequency band occupied by the frequency channel used in the first wireless communication system in the second frequency band are set.

  Therefore, according to the radio communication system configured as described above, in the second radio communication system, the second communication control means (more specifically, the channel setting means) is based on the frequency channel used in the first radio communication system. Since the frequency channel used by itself is set so that the frequency channel band is not included, radio wave interference between the wireless communication systems can be easily and efficiently prevented.

  Here, the channel setting means can appropriately set the frequency channel in the second frequency band as long as it does not include the occupied frequency band of the frequency channel used in the first wireless communication system. When a frequency channel adjacent to a frequency channel used in the system is used in the second wireless communication system, although there is no complete overlap, the use channels of each system are close to each other, so that some radio wave interference May occur.

  Therefore, more preferably, the channel setting means includes a frequency band occupied by the frequency channel indicated by the channel information and having a frequency band wider than the occupied frequency band as defined in claim 2. As a frequency band not used in the system, one or a plurality of frequency channels not included in the unused frequency band may be set as frequency channels used in the second wireless communication system.

  That is, it does not mean that any channel can be used as long as it does not overlap with the frequency band used in the first radio communication system, but it is as far away from the occupied frequency band of the frequency channel used in the first radio communication system as possible. The frequency channel is used in the second wireless communication system.

  According to the wireless communication system configured as described above, the second wireless communication system uses not only the frequency channel used in the first wireless communication system but also the frequencies near the frequency channel for communication. In addition, radio wave interference between the two wireless communication systems can be prevented more reliably.

  The setting of the frequency channel by the channel setting means can be performed as described in claim 3. That is, the invention according to claim 3 is the radio communication system according to claim 1 or 2, wherein the second communication control means is provided for each of the plurality of frequency channels used in radio communication of the first radio communication system. On the other hand, an available channel table is provided in which frequency channels that can be used in the second radio communication system are associated with each other among a plurality of frequency channels in the second radio communication system. Then, the channel setting means sets one or a plurality of frequency channels associated with the frequency channel indicated by the channel information in the usable channel table as a frequency channel used in the second wireless communication system.

  According to the wireless communication system configured as described above, the frequency channels that can be used in the second wireless communication system can be known by referring to the usable channel table. This can be performed efficiently, and the communication efficiency of the entire system can be improved.

  The wireless communication system according to each of the first to third aspects comprises a notification means for notifying the second communication control means of the channel information received by the reception means, as described in claim 4, by the notification means. The channel setting means may be configured to set the frequency channel based on the notified channel information.

  According to the wireless communication system configured as described above, since the channel used in the first wireless communication system is reliably reflected in the second wireless communication system, coexistence of each wireless communication system (prevention of radio wave interference) ) Can be realized more reliably.

  In this case, as described in claim 5, the storage means for storing the channel information received by the receiving means is provided, and the notification means notifies the second communication control means of the channel information stored in the storage means. Can be configured to. By storing the channel information in the storage unit in this way, it is possible to reliably hold information on the frequency channel used on the first wireless communication system side, and it is possible to more stably coexist each wireless communication system. .

  The notification of the channel information by the notification means may be performed at regular time intervals, for example, but more preferably, every time wireless communication is performed in the first wireless communication system as described in claim 6 It is good to notify. That is, the notification means notifies the second communication control means of the channel information received by the reception means every time wireless communication is performed in the first wireless communication system. Each time the channel information is notified by the notification means, the channel setting means sets the frequency channel based on the notified channel information, and the second communication control means sets the set frequency channel to the first The second communication device sets the frequency channel transmitted from the second communication control means as the frequency channel used in wireless communication between itself and the second communication control means.

  According to the wireless communication system configured as described above, each time wireless communication is performed in the first wireless communication system, both the second communication control unit and the second communication device are used in the second wireless communication system. The frequency channel is set. Therefore, in the second wireless communication system, an appropriate frequency channel is always set according to the latest communication environment, and communication can be started immediately using the appropriate frequency channel when performing wireless communication.

  Furthermore, as described in claim 7, whether the second communication control means is in a usable state for each frequency channel set by the channel setting means when performing wireless communication with the second communication device. It is preferable to provide a channel state determination unit for determining whether or not to perform wireless communication with the second communication apparatus using the frequency channel determined to be usable by the channel state determination unit.

  In other words, when the second communication control means performs wireless communication, the frequency channel set by the channel setting means is not used as it is, but it is reconfirmed whether the set frequency channel is surely usable. To do. Then, wireless communication is performed with the second communication device using the frequency channel determined to be usable.

  In this way, the second radio communication system can more reliably set and use a usable frequency channel (a frequency channel that does not cause radio wave interference with the first radio communication system). Can be more reliably prevented. As a method for determining whether or not the frequency channel can be used, for example, it can be performed by measuring a BER (bit error rate).

  In the wireless communication system according to any one of the first to seventh aspects, the first communication method is a spread spectrum communication method based on the direct spread method, and the second communication is performed. The present invention can be applied when the system is a spread spectrum communication system using a frequency hopping system, and in this case, both communication systems can coexist well.

  In this case, as in claim 9, the first wireless communication system is connected so that the first communication control means can communicate with the first communication device wirelessly or by wire via the first communication device. A wireless LAN system capable of mutual communication with a communication terminal, wherein the second wireless communication system uses the second communication control means as a parent device and the second communication device as a child device, and the parent device and the child device. A digital cordless telephone system capable of transmitting and receiving voice signals converted into digital data between the two is particularly effective.

  That is, in a digital cordless telephone system using a spread spectrum communication system using a frequency hopping system, if a frequency channel used for wireless communication (a frequency channel to be hopped) overlaps a frequency channel being used in a wireless LAN, Interference causes the call quality at the handset of the digital cordless telephone system to deteriorate. Therefore, if the present invention is applied to a wireless communication system having a wireless LAN and a digital cordless telephone system, it is possible to maintain good call quality at the handset.

  If the present invention is applied in a configuration in which the first communication control means and the second communication control means are provided in the same casing as described in claim 10, radio wave interference is prevented. This is particularly effective because both parties can perform good communication.

The invention according to claim 11 is a first wireless communication system having a first communication control means and a first communication device capable of wirelessly communicating with the first communication control means by a predetermined first communication method. And a second wireless communication system having a second communication device capable of wirelessly communicating with the second communication control means in a second communication method different from the second communication control means and the first communication method. Wireless communication used in a wireless communication system having a first frequency band used in wireless communication in the first wireless communication system and a second frequency band used in wireless communication in the second wireless communication system. Is the method. The first communication control means uses a frequency channel indicated by channel information transmitted from the first communication device among a plurality of frequency channels in the first frequency band for wireless communication with the first communication device. A frequency channel is set, and wireless communication with the first communication apparatus is performed using the set frequency channel . Further, the second communication control means uses the one or more frequency channels that are not included in the frequency band occupied by the frequency channel indicated by the channel information, among the plurality of frequency channels in the second frequency band. Wireless communication with the second communication device is performed.

According to the above wireless communication method, in the second wireless communication system, the channel setting means itself (based on the frequency channel used in the first wireless communication system so as not to include the band of the frequency channel ( Since the frequency channel used in the second radio communication system is set, similarly to the first aspect of the invention, radio wave interference between the radio communication systems can be easily and efficiently prevented.
According to a twelfth aspect of the present invention, there is provided a first communication control means capable of wirelessly communicating with the first communication device in a predetermined first communication method, and a second in a predetermined second communication method. And a second communication control means capable of wireless communication with each other, and a first frequency band used in wireless communication by the first communication method and a second frequency used in wireless communication by the second communication method. The communication control device is configured to overlap the frequency band of the first communication device, and the communication control device includes any one of a plurality of frequency channels in the first frequency band from the first communication device. And transmitted as channel information indicating a frequency channel used in the wireless communication of the first wireless communication system. The first communication control means includes receiving means for receiving channel information transmitted from the first communication apparatus, and wireless communication with the first communication apparatus based on the channel information received by the receiving means. The second communication control means occupies the frequency channel indicated by the channel information received by the receiving means among the plurality of frequency channels in the second frequency band. Channel setting means for setting one or a plurality of frequency channels not included in the frequency band to be used as frequency channels used in wireless communication of the second wireless communication system.

Preferred embodiments of the present invention will be described below with reference to the drawings.
(1) Overall Configuration of Radio Communication System FIG. 1 shows a schematic configuration of a radio communication system according to this embodiment. As shown in FIG. 1, a wireless communication system 1 according to this embodiment includes a multifunction device 2 having a wireless LAN function and a digital cordless telephone function, and the multifunction device 2 and another wireless LAN terminal 5 or a wired LAN terminal 7. A digital cordless (CL) cordless handset 4 (hereinafter simply referred to as “cordless”) that functions as a cordless handset in a digital cordless telephone that transmits and receives voice signals and the like wirelessly with the access point 3 that relays communications between the mobile phone and the like. It is called "child machine".

  The multifunction machine 2 includes a digital cordless communication control unit 20 responsible for a cordless telephone function, a wireless LAN control unit 30 responsible for a wireless LAN function, and a main control unit 10 that performs overall control of these control units 20 and 30. The digital cordless communication control unit 20 is connected to a telephone line network (external line) 9, and thus, an external line call can be performed from the multifunction device 2 via the telephone line network 9.

  Of the cordless telephone functions, the cordless communication control unit 20 functions as a base unit, and performs wireless communication with the cordless handset 4 via the antenna 20a. A wireless communication method between the digital cordless communication control unit 20 and the cordless handset 4, that is, a communication method used in the digital cordless telephone function is a spread spectrum communication method (FHSS) based on a frequency hopping method.

  Wireless communication by this FHSS method is performed in a 2.4 GHz frequency band (ISM band). Specifically, as shown in FIG. 5, 89 channels from ch1 to ch89 are set in a band of 2.40 GHz to 2.48 GHz. The bandwidth of each channel is about 1 MHz. Then, a predetermined plurality of channels among 89 channels are hopped at regular intervals (for example, approximately every 0.1 seconds) according to a preset hopping sequence. The channel to be hopped is set by the digital cordless communication control unit 20, and the set channel is transmitted to the cordless handset 4. Therefore, the cordless handset 4 sets its own hopping channel according to the hopping channel data transmitted from the digital cordless communication control unit 20.

  In the present embodiment, when communication by a wireless LAN is performed (when wireless communication is performed between the wireless LAN control unit 30 and the access point 3), the wireless LAN is used. A hopping channel is selected and set from other frequency bands excluding the frequency band. This will be described in detail later.

  On the other hand, the wireless LAN control unit 30 performs wireless communication with the access point 3 using the spread spectrum communication method (DSSS) based on the direct spread method via the antenna 30a. This DSSS wireless communication is also performed in the 2.4 GHz ISM band. Specifically, as shown in FIG. 5, 14 channels from ch1 to ch14 are set in the band of 2.40 GHz to 2.48 GHz. The bandwidth of each channel is about 25 MHz. Therefore, in this DSSS, frequency bands overlap between different channels as shown in FIG.

The access point 3 that functions as a relay device in the wireless LAN is connected to a wired LAN terminal 7 and an external Internet network 8 via a router 6. As a result, the wireless LAN control unit 30 can communicate with other wireless LAN terminals 5 via the access point 3 and can also communicate with the wired LAN (wired LAN) via the access point 3.
Connection to the terminal 7 or the like, and thus connection to the Internet network 8 becomes possible.

  The access point 3 determines a channel used in the wireless LAN between the MFP 2 and the access point 3. The access point 3 transmits channel information indicating one channel set by itself among the channels 1 to 14 in the DSSS system to the outside by a beacon signal periodically transmitted by the access point 3. Therefore, the wireless LAN control unit 30 in the multifunction device 2 sets a channel used for communication with the access point 3 based on channel information included in the beacon signal transmitted from the access point 3.

  As described above, in the wireless communication system 1 according to the present embodiment, both the digital cordless communication control unit 20 that realizes the cordless telephone function and the wireless LAN control unit 30 that realizes the wireless LAN function are mounted in the multifunction machine 2. ing. Each control unit 20 and 30 performs wireless communication with the outside (cordless handset 4 or access point 3) using a corresponding communication method.

(2) Configuration of the MFP Next, the internal configuration of the MFP 2 will be described in more detail based on FIG. As described above, the MFP 2 includes the main control unit 10, the digital cordless communication control unit 20, and the wireless LAN control unit 30, and further includes a user including a handset 43, a display 25b, operation buttons 25a, and the like. Via an interface unit (hereinafter referred to as “user I / F”) 25, an audio input / output unit 42 for inputting / outputting audio signals, a reproducing unit 41 for reproducing audio based on various audio signals stored in advance, and the telephone line network 9 NCU (network control unit) 44 for inputting / outputting the audio signal transmitted in this way, a path switching unit 46 for switching the transmission path of the audio signal inside the multi function device 2 and the like.

  Among these, the main control unit 10 includes a ROM 12 in which various control programs for realizing various functions in the multifunction device 2 are stored, and a CPU 11 that executes the various control programs stored in the ROM 12. Further, the CPU 11 includes a RAM 13 in which various data are temporarily stored when performing various calculations. As will be described later, the RAM 13 also stores channel (ch) information 15 indicating a channel in use in the wireless LAN.

  Furthermore, various programs and data are also stored in the EEPROM 14, which is an electrically rewritable nonvolatile memory, and is appropriately executed and used by the CPU 11 as necessary.

  The voice input / output unit 42 includes a speaker, a microphone, and a drive circuit that drives these, not shown, and can perform so-called hands-free calling using the speaker and microphone as a handset, in addition to outputting voice based on a voice signal from the speaker. It is configured as follows.

  The playback unit 41 receives voice signals such as a ringing tone used when receiving an incoming call, a holding tone used when holding a voice call, and an alarm sound for notifying that a set time has come. In response to a command from the main control unit 10, the stored audio signal is reproduced. The reproduced audio signal is appropriately output from a speaker provided in the audio input / output unit 42 or a speaker (not shown) in the handset 43.

  Further, the route switching unit 46 uses a handset 43, a voice input / output unit 42, a digital cordless transmission path to be used by the multifunction device 2 for input / output of voice signals to / from the outside when an operation for starting a call is performed. Switch to any one of the communication control units 20. Specifically, when the handset 43 is removed from the multifunction device 2 main body, the transmission path is switched to the handset 43 side, and an operation for starting a hands-free call is performed by the operation button 25a of the user I / F 25. In this case, the transmission path is switched to the voice input / output unit 42, and when an operation for starting a call is performed by the cordless handset 4, the transmission path is switched to the digital cordless communication control unit 20. Among these, the switching to the digital cordless communication control unit 20 is actually performed after the transmission path is switched to the main control unit 10 side and the analog audio signal is converted into digital data by the main control unit 10. This is done by outputting to the digital cordless communication control unit 20. The voice data transmitted from the cordless handset 4 and received by the digital cordless communication control unit 20 is also converted into an analog voice signal by the main control unit 10 and then the telephone line network 9 side via the path switching unit 46. Is sent to.

  Next, the digital cordless communication control unit 20 is a module that performs wireless communication using the FHSS method with the cordless handset 4, and includes a baseband processing unit 21 and an RF unit 26.

  The baseband processing unit 21 modulates audio data digitized by the main control unit 10 with a predetermined modulation method (for example, FSK, PSK, etc.), and modulation (frequency hopping) in the RF unit 26. ) And an available channel table 23 used when setting the channel to be hopped.

  Specifically, the usable channel table 23 is as shown in FIG. 6, and all channels and use-prohibited channels that can be used in the digital cordless telephone are associated with each channel (ch1 to ch14) of the wireless LAN. It is a thing. As described above, the channel information 15 being used in the wireless LAN is stored in the RAM 13 of the main control unit 10. Therefore, the baseband processing unit 21 sets a hopping channel by referring to the usable channel table 23 based on the channel information 15 stored in the RAM 13.

  As an example, when ch1 is used in the wireless LAN, the baseband processing unit 21 refers to the usable channel table 23 based on the information. In the usable channel table, ch1 to ch25 are set as the use-prohibited channels on the digital cordless telephone side when the wireless LAN use channel is ch1, and the other ch26 to ch89 are set as usable channels.

  That is, when the channel used in the wireless LAN is ch1, as shown in FIG. 5, ch1 to ch25 in the FHSS scheme overlap with ch1 on the wireless LAN side. For this reason, this overlapping channel is prohibited from being used in the FHSS system. The same applies to other channels in the wireless LAN. As shown in FIG. 6, for each channel of the wireless LAN, a channel whose frequency band overlaps with the wireless LAN side among the channels of the FHSS system is a prohibited channel, and the others These channels are tabulated as usable channels.

  Therefore, when ch1 is used on the wireless LAN side, the baseband processing unit 21 refers to the usable channel table 23 and selects a predetermined number of channels from the FHSS chs 26 to 89 that are usable. Select and set. Also, the order of hopping (hopping sequence) is set.

  The RF unit 26 further modulates the audio data modulated by the baseband processing unit 21 by the FHSS method, and the secondary modulation / demodulation unit 27 applies the audio data from the baseband processing unit 21 to the audio data. Then, frequency hopping processing is performed in accordance with the hopping channel and hopping sequence set in the baseband processing unit 21. The audio data subjected to the frequency hopping process in this way is wirelessly transmitted via the antenna 20a.

  The digital cordless communication control unit 20 periodically transmits the set hopping channel and hopping sequence to the cordless slave unit 4. Therefore, the cordless handset 4 can always acquire the latest setting information related to frequency hopping and reflect it on itself.

  Further, when the audio data transmitted from the cordless handset 4 is received by the antenna 20a, the audio data is first demodulated by the secondary modulation / demodulation unit 27 of the RF unit 26 in accordance with the FHSS method. That is, it is restored to audio data before frequency hopping. The audio data demodulated by the secondary modulation / demodulation unit 27 is further demodulated into the original audio data by the primary modulation / demodulation unit 22 of the baseband processing unit 21. Thereafter, the voice data is converted into an analog voice signal by the main control unit 10 and sent to the telephone line network 9.

Next, the wireless LAN control unit 30 is a module that performs wireless communication using the DSSS method with the access point 3, and includes a baseband processing unit 31 and an RF unit 36.
The baseband processing unit 31 includes a primary modulation / demodulation unit 32 that modulates various data instructed to be transmitted by the wireless LAN in the multi-function device 2 with a predetermined modulation method (for example, FSK, PSK, etc.), and a primary modulation / demodulation unit 32. And a secondary modulation / demodulation unit 33 that further modulates the modulated data by a DSSS method (spread spectrum using a spread code). Further, the channel information included in the beacon signal periodically transmitted from the access point 3 is acquired, and the channel information is output to the RF unit 36 and the main control unit 10.

  Based on the channel information from the baseband processing unit 31 (that is, channel information notified from the access point 3), the RF unit 36 indicates the data modulated and spread spectrum by the baseband processing unit 31. Up-convert to channel frequency (2.4 GHz band). The data up-converted in this way is wirelessly transmitted via the antenna 30a.

  When data transmitted from the access point 3 is received by the antenna 30a, the RF unit 36 first down-converts the frequency of the data. The down-converted data is demodulated in the DSSS system by the secondary modulation / demodulation unit 33 of the baseband processing unit 31 and further demodulated into the original baseband signal by the primary modulation / demodulation unit 32. Channel information included in the baseband signal is stored in the RAM 13 in the main control unit 10.

  Each time the beacon signal (including channel information) periodically transmitted from the access point 3 is received by the wireless LAN control unit 30, the main control unit 10 acquires the channel information and stores it in the RAM 13. The channel information is notified to the digital cordless communication control unit 20. Each time the digital cordless communication control unit 20 receives notification of the channel information, the digital cordless communication control unit 20 sets a channel to be used in the FHSS according to the usable channel table 23.

(3) Configuration of Cordless Slave Unit FIG. 3 shows a configuration of the cordless slave unit 4. As shown in FIG. 3, the cordless handset 4 includes a control unit 51 that controls the operation of the whole handset 4, a transmission / reception unit 53 that includes a speaker and a microphone (not shown), and a drive circuit that drives them, a display (not shown), User I / F 54 composed of operation buttons, a reproduction unit 55 that reproduces sound based on various audio signals stored in advance, a speaker that outputs sound reproduced by the reproduction unit 55, and a speaker that includes a drive circuit that drives the speaker A slave unit communication control unit 52 that transmits and receives various types of data including voice data between the unit 56 and the multifunction device 2 (the digital cordless communication control unit 20) by wireless communication.

  The control unit 51 includes a CPU 61, a ROM 62, a RAM 63, and an EEPROM 64, similar to the main control unit 10 of the multifunction machine 2. The RAM 63 stores channel information 65 (hopping channel) transmitted from the multifunction device 2.

  The slave unit communication control unit 52 basically has the same function as the digital cordless communication control unit 20 of the multifunction machine 2, and the voice data converted into digital data by the control unit 51 is converted into the baseband processing unit 66. Is subjected to primary modulation (FSK, QSK, etc.), frequency-hopped by the RF unit 67, and wirelessly transmitted from the antenna 4a. Further, the data (FHSS method) received by the antenna 4a is demodulated into data before frequency hopping by the RF unit 67, and further demodulated by the baseband processing unit 66 into the original baseband signal. When the demodulated baseband signal includes data related to frequency hopping (such as a hopping channel / hopping sequence), the data is stored in the RAM 63 as channel information 65.

(4) Configuration of Access Point FIG. 4 shows the configuration of the access point 3. As shown in FIG. 4, the access point 3 includes a control unit 71 that controls the operation of the entire access point 3, a user I / F 74 that includes a display and operation buttons (not shown), and a network other than the wireless LAN (for example, a wired LAN). And the like, and a wireless LAN control unit 72 that transmits and receives various data by wireless communication between the multifunction device 2 (the wireless LAN control unit 30 thereof). I have.

  The control unit 71 sets a channel to be used in the wireless LAN, and transmits the setting information (channel information) to an external wireless LAN terminal (including the multifunction device 2) via the wireless LAN control unit 72 and the antenna 3a. .

  The wireless LAN control unit 72 basically has the same function as the wireless LAN control unit 30 in the multifunction device 2, and the RF unit 76 and the baseband are similar to the wireless LAN control unit 30 in the multifunction device 2. And a processing unit 77.

(5) Various Processes Executed in the Wireless Communication System Next, among various processes executed in the wireless communication system 1 of the present embodiment, particularly based on the channels used in the wireless LAN and the usable channel table 23. Each process for setting a use channel in a digital cordless telephone will be described.

  First, FIG. 7 is a flowchart showing a wireless LAN communication process executed by the main control unit 10 of the multifunction machine 2. This wireless LAN communication process is executed continuously at a constant cycle after the multifunction device 2 is powered on.

  When this process is started, it is first determined whether or not any command (data) is received from the access point 3 (S110). If received, the connection with the access point 3 is established (S110; YES). (S130). If no command is received from the access point 3 (S110; NO), it is further determined whether or not there is a command (data) transmission request from the multi-function device 2 to the access point 3 (S120). If there is no command transmission request from the multifunction device 2, the process returns to S110, but if there is a command transmission request, a connection with the access point 3 is established (S130).

  When the connection with the access point 3 is established, the channel information 15 (indicating the channel used in the wireless LAN) transmitted from the access point 3 is stored in the RAM 13 (S140), and the stored channel information is digitally cordless. The communication control unit 20 is notified (S150).

  Thereafter, communication by the wireless LAN is executed between the wireless LAN control unit 30 and the access point 3 (S160). When the communication is terminated (S170; YES), this wireless LAN communication process is temporarily terminated.

  Next, digital cordless communication processing executed by the digital cordless communication control unit 20 of the multifunction machine 2 will be described based on the flowchart of FIG. When this process is started, it is first determined whether or not there is a notification of a used channel from the wireless LAN side (S210). This notification is made by the process of S150 in the wireless LAN communication process shown in FIG.

  If there is no such notification (S210; NO), the process proceeds to the processing after S250. If this notification is received (S210; YES), the frequency of the notified wireless LAN side channel is determined according to the usable channel table 23. A channel (digital cordless channel) used for frequency hopping in the digital cordless telephone is set so as not to overlap with the band (S220). The set digital cordless channel is stored in a memory (not shown) in the baseband processing unit 21 (S230) and is also transmitted to the cordless slave unit 4 (S240). That is, every time there is a notification of channel information used in the wireless LAN, the channel used in the digital cordless telephone is set and the set channel is transmitted to the cordless handset 4 as well. As a result, not only the digital cordless communication control unit 20 but also the cordless slave unit 4 is always set to the latest channel (channel that does not cause radio wave interference with the wireless LAN).

  Thereafter, the presence / absence of a communication request with the cordless handset 4 is determined (S250). If there is no communication request, this digital cordless communication process is temporarily terminated. If there is a communication request (S250; YES), Communication processing with the cordless handset 4 is executed. At this time, frequency hopping is performed using the digital cordless channel set in the process of s220. When the communication is finished (S270; YES), this digital cordless communication process is once finished.

  Next, handset communication processing executed by the cordless handset 4 will be described based on the flowchart of FIG. When this process is started, it is first determined whether or not a digital cordless use channel has been received from the multi-function device 2 (that is, from the digital cordless communication control unit 20) (S310). Here, if it is not received, the process proceeds to S330 as it is, but if it is received (S310; YES), the received digital cordless channel is set as a communication channel used for wireless communication with the MFP 2 ( S320).

  Thereafter, it is determined whether or not there is a digital cordless telephone communication request, that is, a digital cordless communication from the multifunction device 2 side or a digital cordless communication request by the cordless slave unit 4 (S330). If the request is made (that is, when there is a call from the multi-function device 2 or a call request from the cordless slave device 4), the above-mentioned slave unit communication process is temporarily terminated. Communication using the communication channel thus made as the hopping channel is executed (S340). When the communication is completed (S350; YES), this slave unit communication process is once terminated.

(6) Effects of this Embodiment The wireless communication system of this embodiment described above includes both the wireless LAN control unit 30 and the digital cordless communication control unit 20, and has both a wireless LAN function and a digital cordless telephone function. In the multifunction device 2, the channel used in the wireless LAN is notified to the digital cordless communication control unit 20. As a result, the digital cordless communication control unit 20 uses channels (hopping) used for communication in digital cordless telephones based on the usable channel table 23 (see FIG. 6) so as not to overlap with the frequency band of the channels used in the wireless LAN. Channel). The set channel is transmitted to the cordless handset 4 every time it is set, and the cordless handset 4 sets its own channel based on the transmitted channel.

  Therefore, according to the wireless communication system of this embodiment, the digital cordless communication control unit 20 in the MFP 2 uses the channel (hopping) used by itself so that the frequency band of the channel used in the wireless LAN is not included. Therefore, radio wave interference between the wireless LAN and the digital cordless telephone can be easily and efficiently prevented.

  In particular, since the usable channel table shown in FIG. 6 is referred to when setting the hopping channel in the FHSS system, the used channel in the digital cordless telephone can be set quickly and efficiently, and the system Overall communication efficiency is improved.

  Further, every time communication by wireless LAN is performed, the use channel is notified to the digital cordless communication control unit 20, and based on this, the use channel is set on the digital cordless telephone side. For this reason, in a digital cordless telephone, an appropriate channel setting is always made according to the latest communication environment. Therefore, when performing wireless communication with the cordless handset 4, the appropriate channel is used immediately. Communication can be started.

  Furthermore, if a digital cordless telephone using a spread spectrum communication system using a frequency hopping method and a wireless LAN using a spread spectrum communication system using a direct spread system exist in the same area, the radio interference between the two may be temporarily avoided. If this occurs, the call quality of the cordless cordless handset 4 of the digital cordless phone will deteriorate, but in this embodiment, the channel used on the codigital cordless phone side does not overlap with the channel used in the wireless LAN as described above. I am doing so. Therefore, it is possible to maintain the quality of the voice call by the cordless handset 4 favorably. This is particularly effective when the digital cordless telephone system and the wireless LAN system exist in the same casing as in the multi-function device 2 of the present embodiment.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. In this embodiment, the wireless LAN control unit 30 in the multifunction device 2 corresponds to the first communication control means of the present invention, the access point 3 corresponds to the first communication device of the present invention, and the digital cordless communication control unit. 20 corresponds to the second communication control means of the present invention, the cordless handset 4 corresponds to the second communication apparatus of the present invention, and the wireless LAN control unit 72 provided in the access point 3 corresponds to the transmission means of the present invention. The main control unit 10 corresponds to the notification unit of the present invention, and the RAM 13 in the main control unit 10 corresponds to the storage unit of the present invention. In this embodiment, the frequency band that can be used for communication in both the wireless LAN and the digital cordless telephone is a band of 2.40 to 2.48 GHz as shown in FIG. Correspond to the first frequency band and the second frequency band.

(7) Modifications Embodiments of the present invention are not limited to the above-described embodiments, and it goes without saying that various forms can be adopted as long as they belong to the technical scope of the present invention.

  For example, in the above embodiment, every time communication by wireless LAN is performed, the channel used is stored in the RAM 13 as the channel information 15 and notified to the digital cordless communication control unit 20. When there is a communication (call) request from the cordless handset 4, the channel information 15 (channel used in the wireless LAN) stored in the RAM 13 at that time is obtained, and the channel in the digital cordless phone is determined based on the channel information 15 You may make it set.

  Even if it does in this way, since the suitable channel at the time of communicating by the cordless subunit | mobile_unit 4 will be set, the electromagnetic wave interference with wireless LAN can be prevented. However, every time the cordless cordless handset 4 tries to communicate, it is necessary to set a use channel on the cordless telephone side based on the channel of the wireless LAN at that time. 4 communication start timing may be slightly delayed. For this reason, in order to quickly start communication by the cordless handset 4, it is desirable to set a use channel in a digital cordless telephone in advance every time wireless LAN communication is performed as in the above embodiment.

  Further, in the above embodiment, since the channel used in the digital cordless telephone is set so as not to overlap with the frequency band of the channel used in the wireless LAN, there is normally no possibility that mutual radio wave interference occurs. However, depending on the surrounding environment, there is a possibility that a channel having a bad communication state may be generated due to some factor even though the channel is a band not used in the wireless LAN.

  Therefore, when starting the communication with the cordless handset 4, the digital cordless communication control unit 20 does not use the set channel as it is, but determines whether the set channel can be used. It is possible to use only the channels that are determined to be usable. A specific processing example is shown in FIG.

  FIG. 10 is a flowchart showing a used channel search process executed when a communication request is received from the cordless slave unit 4. When this process is started, it is first determined whether or not there is a communication request from the cordless handset 4 (S410). If there is no communication request, this process is terminated as it is. If there is a communication request (S410; YES), the currently set communication channel (digital cordless channel) is acquired (S420).

  Subsequently, the radio wave environment is searched for each of the acquired communication channels. Specifically, it can be performed, for example, by measuring a BER (bit error rate). As a result of the radio wave environment search, only a channel having a good radio wave environment is set as a new channel, and communication with the cordless slave unit 4 is executed using the new channel (S440). Thereafter, when communication with the cordless handset 4 is completed (S450; YES), this use channel search process is terminated.

  In this way, by searching the radio wave environment for channels that have already been set up (with care), channels that can be used with digital cordless phones (channels that do not cause radio wave interference with the wireless LAN) can be more reliably determined. Can be used.

  In addition, for the setting of the channel used for the digital cordless telephone based on the usable channel table (see FIG. 6), which channel is set as the “usable channel” for the channel used for the wireless LAN. However, more preferably, a channel that is as far as possible from the frequency band corresponding to the channel used in the wireless LAN may be set.

  That is, for example, when ch1 is used in a wireless LAN, according to the usable channel table of FIG. 6, ch26 to ch89 can be used among 89 channels in a digital cordless telephone, but use is prohibited. Channels that are as far away as possible from ch1 to ch25 set as channels (for example, after ch50) are set. By doing in this way, it becomes possible to prevent the radio wave interference with the wireless LAN more reliably.

  In the above embodiment, when the channel used for frequency hopping is set in the digital cordless communication control unit 20, the channel setting is performed based on the usable channel table 23. Thus, usable channels may be derived by numerical calculation, and a plurality of hopping channels may be set from the derived channels.

  Specifically, when the wireless LAN use channel is “x” and the digital cordless telephone usable channel is “y”, the usable channel y in the digital cordless telephone is expressed by the following equations (1) and (2). It is obtained by. That is, the value of y that satisfies Equation (1) or Equation (2) is an available channel in a digital cordless telephone.

y <5 (x-1) +1 (1)
y> 5 (x-1) +25 (2)
On the contrary, if the use prohibited channel in the digital cordless telephone is “y”, the use prohibited channel y is obtained by the following equation (3).

5 (x−1) + 1 ≦ y ≦ 5 (x−1) +25 (3)
As described above, if the usable channel (or the prohibited channel) in the digital cordless telephone is obtained by using the above formula (1) and the formula (2) or the formula (3), the rest of the usable channels will be used. The hopping channel may be set as appropriate.

  Further, the multifunction device 2 of the above embodiment may have a function of limiting the hopping channel by a user operation in addition to the function of setting the hopping channel used in the digital cordless telephone based on the usable channel table. .

  Specifically, for example, four selection menus “automatic”, “01”, “02”, and “03” are prepared. Among these, “automatic” is a mode in which the digital cordless communication control unit 20 automatically sets a hopping channel by the method described in the above embodiment (a method based on the usable channel table).

  “01” is a mode in which communication is performed while avoiding a frequency band occupied by ch1 in a wireless LAN (corresponding to ch1 to ch25 in a digital cordless telephone). Therefore, when “01” is selected, the digital cordless communication control unit 20 forces the hopping channel from among ch26 to ch89 in the digital cordless phone regardless of which channel is used in the wireless LAN. Set.

  “02” is a mode in which communication is performed while avoiding the frequency band occupied by ch 6 in the wireless LAN (corresponding to ch 26 to ch 50 in the digital cordless telephone). Therefore, when “02” is selected, the digital cordless communication control unit 20 forces the channels ch1 to ch25 and ch51 to ch89 in the digital cordless phone regardless of which channel is used in the wireless LAN. Set the hopping channel from the inside.

  “03” is a mode in which communication is performed while avoiding a frequency band occupied by ch11 in a wireless LAN (corresponding to ch51 to ch75 in a digital cordless telephone). Therefore, when “03” is selected, the digital cordless communication control unit 20 forcibly sets ch1 to ch50 and ch76 to ch89 in the digital cordless telephone regardless of which channel is used in the wireless LAN. Set the hopping channel from the inside.

  Of course, the above four modes are merely examples, and modes corresponding to all 14 channels of the wireless LAN may be provided. In this way, when the user recognizes the wireless LAN use channel in advance, the use channel on the digital cordless telephone side can be set (a band to be avoided) according to the wireless LAN channel. The processing load of the digital cordless communication control unit 20 is reduced.

  In the above embodiment, the case where the wireless LAN of IEEE802.11b and the digital cordless telephone of the frequency hopping method coexist in the same area (in the same housing) has been described, but other than this, for example, IEEE802.11b and The present invention is applied to any communication system capable of setting one use channel while avoiding one use channel, although frequency bands overlap, such as when Bluetooth coexists or IEEE 802.11g and a digital cordless phone coexist. it can.

It is a block diagram which shows schematic structure of the radio | wireless communications system of this embodiment. 1 is a block diagram illustrating a configuration of a multifunction machine. It is a block diagram which shows the structure of a digital cordless subunit | mobile_unit. It is a block diagram which shows the structure of an access point. It is explanatory drawing which shows the channel arrangement | sequence in wireless LAN (DSSS system) and a digital cordless telephone (FHSS system). It is explanatory drawing which shows a digital cordless usable channel table. 6 is a flowchart illustrating wireless LAN communication processing executed by a main control unit of the multifunction machine. It is a flowchart which shows the digital cordless communication process performed in the digital cordless communication control part of a multifunction device. It is a flowchart which shows the subunit | mobile_unit communication process performed with a cordless subunit | mobile_unit. It is a flowchart which shows the use channel search process performed in a digital cordless communication control part.

DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 2 ... Multifunction machine, 3 ... Access point, 3a, 4a, 20a, 30a ... Antenna, 4 ... Digital cordless cordless handset, 5 ... Wireless LAN terminal, 6 ... Router, 7 ... Wired LAN terminal, 8 ... Internet network, 9 ... Telephone line network, 10 ... Main control unit, 15, 65 ... Channel information, 20 ... Digital cordless communication control unit, 21, 31, 66, 77 ... Baseband processing unit, 22, 32 ... Primary modulation / demodulation , 23 ... Usable channel table, 26, 36, 67, 76 ... RF part, 27, 33 ... Secondary modulation / demodulation part, 30, 72 ... Wireless LAN control part, 41, 55 ... Playback part, 42 ... Audio input / output , 43... Handset, 46... Path switching unit, 51, 71... Control unit, 52 .. handset communication control unit, 53.

Claims (12)

A first wireless communication system having a first communication control means and a first communication device capable of wirelessly communicating with the first communication control means in a predetermined first communication method;
A second wireless communication system having a second communication device capable of wirelessly communicating with the second communication control means in a second communication method different from the second communication control means and the first communication method;
And a first frequency band used in radio communication in the first radio communication system and a second frequency band used in radio communication in the second radio communication system overlap. And
The first communication device uses the first frequency as channel information indicating a frequency channel used in radio communication of the first radio communication system, from any one of a plurality of frequency channels in the first frequency band. A transmission means for transmitting to the communication control means;
The first communication control means includes receiving means for receiving the channel information transmitted from the first communication apparatus, and the first communication control means and the first communication apparatus based on the channel information received by the receiving means. Configured to set the frequency channel used for wireless communication,
The second communication control means is not included in a frequency band occupied by a frequency channel indicated by the channel information received by the receiving means among a plurality of frequency channels in the second frequency band. Alternatively, a wireless communication system comprising channel setting means for setting a plurality of frequency channels to frequency channels used in wireless communication of the second wireless communication system. The wireless communication system according to claim 1,
The channel setting means includes a frequency band occupied by a frequency channel indicated by the channel information and a frequency band wider than the occupied frequency band as a frequency band not used in the second wireless communication system, and a frequency that is not used. One or a plurality of frequency channels not included in the band are set as frequency channels used in the second wireless communication system. The wireless communication system according to claim 1 or 2,
The second communication control unit is configured to, for each of the plurality of frequency channels used in wireless communication of the first wireless communication system, out of the plurality of frequency channels in the second wireless communication system. It has an available channel table that is associated with frequency channels that can be used in the communication system,
The channel setting means sets one or a plurality of frequency channels associated with the frequency channel indicated by the channel information in the usable channel table as a frequency channel used in the second radio communication system. A wireless communication system. The wireless communication system according to any one of claims 1 to 3,
Notification means for notifying the second communication control means of the channel information received by the receiving means;
The wireless communication system, wherein the channel setting means sets the frequency channel based on the channel information notified by the notification means. A wireless communication system according to claim 4,
Storage means for storing the channel information received by the receiving means;
The wireless communication system, wherein the notifying means notifies the second communication control means of the channel information stored in the storage means. The wireless communication system according to claim 4 or 5,
The notification means notifies the second communication control means of the channel information received by the receiving means every time wireless communication is performed in the first wireless communication system,
Every time the channel information is notified by the notification means,
The channel setting means sets the frequency channel based on the notified channel information, the second communication control means transmits the set frequency channel to the second communication device, and the second communication device The communication apparatus sets a frequency channel transmitted from the second communication control means as a frequency channel used in wireless communication between itself and the second communication control means. The wireless communication system according to claim 6,
The second communication control unit determines whether or not each frequency channel set by the channel setting unit is usable when performing wireless communication with the second communication apparatus. A wireless communication system comprising: a determination unit, and performing wireless communication with the second communication device using a frequency channel determined to be usable by the channel state determination unit. A wireless communication system according to claim 1,
The first communication method is a spread spectrum communication method by a direct spread method,
The wireless communication system, wherein the second communication method is a spread spectrum communication method based on a frequency hopping method. The wireless communication system according to claim 8, wherein
In the first wireless communication system, the first communication control means can communicate with a communication terminal that is connected to the first communication device via the first communication device so as to be able to communicate wirelessly or by wire. Wireless LAN system,
The second wireless communication system transmits / receives an audio signal converted into digital data between the parent device and the child device using the second communication control means as a parent device and the second communication device as a child device. A wireless communication system characterized by being a possible digital cordless telephone system. A wireless communication system according to any one of claims 1 to 9,
The wireless communication system, wherein the first communication control means and the second communication control means are provided in the same casing. A first wireless communication system having a first communication control means and a first communication device capable of wirelessly communicating with the first communication control means in a predetermined first communication method;
A second wireless communication system having a second communication device capable of wirelessly communicating with the second communication control means in a second communication method different from the second communication control means and the first communication method;
And used in a radio communication system in which a first frequency band used in radio communication in the first radio communication system and a second frequency band used in radio communication in the second radio communication system overlap. A wireless communication method, comprising:
The first communication control unit is configured to select a frequency channel indicated by channel information transmitted from the first communication device among a plurality of frequency channels in the first frequency band with the first communication device. Set to a frequency channel used in wireless communication, perform wireless communication with the first communication device using the set frequency channel ,
The second communication control means uses one or a plurality of frequency channels that are not included in the frequency band occupied by the frequency channel indicated by the channel information among the plurality of frequency channels in the second frequency band. And wireless communication with the second communication device.   First communication control means capable of wirelessly communicating with the first communication device in a first communication method determined in advance;
  A second communication control means capable of wirelessly communicating with the second communication device in a second communication method determined in advance;
  A communication control device configured to overlap a first frequency band used in wireless communication by the first communication method and a second frequency band used in wireless communication by the second communication method Because
  The communication control device includes a channel in which any one of a plurality of frequency channels in the first frequency band from the first communication device indicates a frequency channel used in wireless communication of the first wireless communication system. Sent as information,
  The first communication control means includes receiving means for receiving channel information transmitted from the first communication apparatus, and the first communication control means communicates with the first communication apparatus based on the channel information received by the receiving means. It is configured to set the frequency channel used for wireless communication,
  The second communication control means is not included in a frequency band occupied by a frequency channel indicated by the channel information received by the receiving means among a plurality of frequency channels in the second frequency band. Or a channel setting means for setting a plurality of frequency channels to frequency channels used in radio communication of the second radio communication system.
  A communication control device.