JP2010178210A - Radio communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication device which can perform radio communication by a plurality of communication systems of the same frequency band using only one device, while keeping a necessary number of good channels. <P>SOLUTION: The radio communication device is provided with a first radio communication means which performs radio communication between main and sub communication devices, and a second communication means which performs radio communication with a plurality of external communication devices. When performing radio communication at the same time with the first radio communication means, the second radio communication means performs radio communication with an external radio communication device selected out of the plurality of external communication devices, in which influence given to the radio communication by the first communication means is small. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication apparatus. In particular, the present invention relates to a wireless communication apparatus including a plurality of wireless communication means that use the same frequency band.

  2. Description of the Related Art Conventionally, there are wireless communication devices that perform data communication or telephone call by wireless communication. In such a wireless communication apparatus, even if the communication method differs between data communication and telephone call, the frequency bands used may overlap.

  For example, a wireless local area network (hereinafter referred to as WLAN) for data communication and a digital cordless telephone (hereinafter referred to as DCL) for telephone calls are any Also use the same frequency band of 2.4 GHz.

  Here, frequency bands and frequency channels used by WLAN and DCL will be described with reference to FIG. FIG. 8 is a schematic diagram illustrating frequency bands and frequency channels used in WLAN and DCL.

  As shown in FIG. 8, each of the WLAN and DCL communication systems uses a frequency band (2.4 GHz band) from 2.4 GHz to 2.5 GHz. And in each communication system, the channel which divided | segmented the 2.4 GHz band into plurality is set. Hereinafter, in order to distinguish channels in each communication method, a channel used in WLAN is a WLAN channel, and a channel used in DCL is a DCL channel.

  In WLAN, the 2.4 GHz band is divided into 14 WLAN channels wch1 to wch14. The WLAN performs wireless communication by a direct spread method that directly spreads transmission data to one WLAN channel while continuously using one of the 14 WLAN channels.

  On the other hand, in the DCL, the 2.4 GHz band is divided into 89 DCL channels dch1 to dch89. The DCL changes (hops) a DCL channel to be used between, for example, 45 DCL channels selected in advance among 89 DCL channels at a predetermined cycle (for example, 1/100 second) called a hopping cycle. Wireless communication is performed by a frequency hopping method.

  In an environment in which a plurality of communication methods are mixed as described above, the same frequency band is used by each communication method, so that radio wave interference may occur between the communication methods. On the other hand, in Patent Documents 1 and 2 below, a Bluetooth module that performs wireless communication with Bluetooth (registered trademark), which is one of the wireless communication systems using the 2.4 GHz band, and IEEE802. 11b discloses a technique for preventing radio wave interference when a wireless LAN module that performs wireless communication in the same area is used.

JP 2002-198867 A JP 2002-198868 A

  The technologies disclosed in Patent Documents 1 and 2 prevent the occurrence of radio wave interference with each other by stopping the use of channels that interfere with each other between the Bluetooth module and the wireless LAN module. However, in an environment where a plurality of WLAN channels are used, when the techniques disclosed in Patent Documents 1 and 2 are applied to a device that performs wireless communication using WLAN and DCL in a single unit, the number of channels that can be used in DCL However, there is a possibility that the necessary number of channels cannot be secured, which is a problem.

  The present invention has been proposed in view of the above problems. An object of the present invention is to provide a wireless communication apparatus capable of performing wireless communication by a plurality of communication methods using the same frequency band by a single unit while securing a necessary number of good channels.

  A wireless communication device according to claim 1 of the present invention includes a main communication device and at least one sub communication device, and performs wireless communication between the main and sub communication devices and also performs wireless communication with a plurality of external communication devices. In the wireless communication apparatus that performs the above, the main wireless communication device uses one of a plurality of first wireless channels provided in a predetermined frequency band and switches the first wireless channel to be used at a predetermined cycle. And a first wireless communication means for performing wireless communication between the sub-communication device and a first wireless channel having a wider bandwidth than the first wireless channel provided in the predetermined frequency band used by the first wireless communication means. A second wireless communication means for performing wireless communication with the external communication device by a second wireless communication method that continuously uses two wireless channels; the first wireless communication means; and the second wireless communication means. Selection means for selecting, from the plurality of external communication devices, an external communication device that has little influence on the wireless communication by the first wireless communication device when both perform wireless communication. The wireless communication means performs wireless communication with the external communication device selected by the selection means when performing wireless communication simultaneously with the first wireless communication means.

  The wireless communication apparatus according to claim 2 of the present invention is the wireless communication apparatus according to claim 1, wherein the selecting means is a wireless communication between an external communication apparatus capable of wireless communication by the second wireless communication means and the external communication apparatus. A radio wave condition measured by the measurement means, comprising: a detection means for detecting the second radio channel used for communication; and a measurement means for measuring the radio wave condition of the second radio channel detected by the detection means. The external communication device is selected based on the above.

  The wireless communication apparatus according to claim 3 of the present invention is the wireless communication apparatus according to claim 2, wherein the measurement means is received as a radio wave state of the second wireless channel in a band corresponding to the second wireless channel. The strength of the radio wave is measured, and the selection unit has less influence on the wireless communication by the first radio communication unit with the external communication device using the second radio channel whose radio wave intensity measured by the measurement unit is weak. It is selected as an external communication device.

  The wireless communication apparatus according to claim 4 of the present invention is the wireless communication apparatus according to claim 3, wherein the measuring means has a radio wave state of the second wireless channel at a center frequency of a band corresponding to the second wireless channel. It is characterized by measuring the intensity of received radio waves.

  The wireless communication apparatus according to claim 5 of the present invention is the wireless communication apparatus according to any one of claims 2 to 4, wherein the detection unit is mounted on the main communication apparatus, and the measurement unit is mounted on the sub communication apparatus. It is implemented.

  The wireless communication apparatus according to claim 6 of the present invention is the wireless communication apparatus according to any one of claims 2 to 5, wherein the detection means periodically detects, and the measurement means periodically performs measurement. It is characterized by that.

  A wireless communication device according to claim 7 of the present invention is the wireless communication device according to any one of claims 1 to 6, wherein the main communication device is a base unit of a digital cordless telephone, and the sub communication device is the digital communication device. A cordless telephone cordless handset, wherein the first wireless communication means is a digital cordless telephone system, the second wireless communication means is a wireless LAN system, and the external communication device is the same network in the wireless LAN. It is an access point having identification information.

  According to the wireless communication device of the first aspect of the present invention, the first wireless communication means can perform wireless communication between the main and secondary communication devices while securing the necessary number of good first wireless channels. .

  According to the wireless communication apparatus of the second aspect of the present invention, the second wireless communication means can avoid the use of the second wireless channel that is highly likely to cause radio wave interference with the first wireless channel.

  According to the wireless communication device of the third aspect of the present invention, the second wireless communication means can avoid the use of the second wireless channel having a high radio field intensity and a high possibility of radio wave interference with the first wireless channel.

  According to the wireless communication device of the fourth aspect of the present invention, the second wireless communication means avoids the use of the second wireless channel having a strong radio wave intensity at the center frequency, which is a frequently used frequency in the wireless channel band. Thus, it is possible to effectively avoid the use of the second wireless channel that has a high possibility of radio wave interference with the first wireless channel. Further, the time required for measuring the radio field intensity by the measuring means can be shortened.

  According to the wireless communication apparatus according to claim 5 of the present invention, the second wireless communication means is optimal for the sub-communication apparatus, that is, the wireless communication with the external communication apparatus having the least influence on the wireless communication by the first wireless communication means. It can be performed. In addition, the configuration of the sub-communication device can be simplified and the cost can be reduced.

  According to the wireless communication apparatus of the sixth aspect of the present invention, it is possible to cope with changes in the surrounding radio wave environment.

  According to the wireless communication apparatus of the seventh aspect of the present invention, it is possible to configure a wireless communication apparatus having a call function using a digital cordless telephone and a data communication function using a WLAN between the parent device and the child device. Further, in a network constructed by assigning common network identification information to a plurality of access points, such as an in-house network, the wireless communication device can change the second wireless channel by selecting an access point to be connected. Therefore, it is possible to avoid the use of the second radio channel that has a high possibility of radio wave interference with the first radio channel.

  According to the wireless communication apparatus of the present invention, wireless communication by a plurality of communication methods using the same frequency band can be performed by one unit while securing a necessary number of good channels.

It is an external view showing a multi-function device. It is a block diagram which shows the structure of a communication system. It is the schematic which shows the network which employ | adopted the communication system of FIG. It is a flowchart of the channel confirmation process of a multi-function device. It is a figure which shows a channel corresponding | compatible table. It is a figure which shows the electromagnetic wave environment in the network of FIG. It is a flowchart which shows the channel selection process at the time of an incoming call of a multi-function device. It is the schematic which showed the frequency band and frequency channel which are used by WLAN and DCL.

  Embodiments will be described with reference to the drawings. FIG. 1 is an external view showing a multi-function device 1 as an example of a wireless communication apparatus of the present invention. The multi-function device 1 includes a parent device 10 and a child device 61. The base unit 10 has a printer function, a FAX function, and the like as well as a WLAN function and a DCL function as a main body of the multi-function device 1. As shown in FIG. 1, a handset 23 is provided on the side surface of the base unit 10. Further, an operation key 15 and an LCD 16 with a touch panel function are provided in front of the upper surface of the base unit 10. The user can input a telephone number or the like into the base unit 10 via the operation keys 15 and the LCD 16.

  FIG. 2 is a block diagram illustrating a configuration of a communication system including the parent device 10 and the child device 61. The base unit 10 mainly includes a CPU 11, a ROM 12, a RAM 13, a WLAN communication control circuit 17, a DCL communication control circuit 19, a handset 23, a voice processing LSI 24, and an NCU (Network Control Unit, hereinafter referred to as NCU) 25. Have. The CPU 11, ROM 12, and RAM 13 are connected to each other via a bus line 26. The handset 23 and the NCU 25 are connected to the voice processing LSI 24. The operation key 15, the LCD 16, the WLAN communication control circuit 17, the DCL communication control circuit 19, the voice processing LSI 24, the NCU 25, and the bus line 26 are connected to each other via the input / output port 27.

  The CPU 11 executes various processes according to programs and parameters stored in the ROM 12 and the RAM 13, or various signals transmitted / received via the WLAN communication control circuit 17, the DCL communication control circuit 19, and the NCU 25. The ROM 12 stores a program for controlling the parent device 10 and the child device 61 constituting the multi-function device 1, various tables that are referred to according to the program, and the like. The RAM 13 stores various data generated in the process that is executed according to the program.

  The WLAN communication control circuit 17 having the WLAN antenna 18 performs WLAN communication 200 that is wireless communication by a direct spreading method with an access point (hereinafter referred to as AP) 51 having the WLAN antenna 52. . The AP 51 is connected to the in-house LAN 500, and the base unit 10 performs data communication with another device (for example, a PC) connected to the in-house LAN 500 via the AP 51.

  The DCL communication control circuit 19 having the DCL antenna 20 performs DCL communication 300, which is radio communication by the frequency hopping method, with the DCL communication control circuit 62 having the DCL antenna 63 of the slave unit 61. The voice processing LSI 24 mutually converts the analog voice signal of the handset 23 and the NCU 25 and the digital signal of the DCL communication control circuit 19. The NCU 25 is connected to the telephone line network 100, and transmits a dial signal to the telephone line network 100, responds to a calling signal from the telephone line network 100, and the like.

  FIG. 3 is a schematic diagram illustrating an example of a network employing the communication system configured as described above. Three APs 51 (51A, 51B, 51C) are connected to the in-house LAN 500, and a common SSID (Service Set Identifier, hereinafter referred to as SSID) is assigned to each AP 51 as network identification information. Each AP 51 uses different WLAN channels wch1, wch5, and wch9 in order to avoid interference and covers different ranges. Such a network form is called an infrastructure mode, and the base unit 10 performs WLAN communication 200 with any of the APs 51 that supervise the WLAN and connects to the in-house LAN 500. Further, the two slave units 61 (61 </ b> A and 61 </ b> B) communicate with the master unit 10 and other telephones connected to the telephone network 100 through the DCL communication 300 with the master unit 10.

  In the network shown in FIG. 3, the multi-function device 1 configured by including the parent device 10 and the two child devices 61 prevents radio wave interference between the WLAN communication 200 and the DCL communication 300 that use the same 2.4 GHz band. Communication is performed while securing the necessary number of good channels. Hereinafter, processing executed in the multi-function device 1 will be described with reference to FIGS. 4 to 7.

  FIG. 4 is a flowchart of the channel confirmation process of the multi-function device 1 for confirming the radio field intensity around the slave device 61 for the WLAN channel used by the master device 10 for the WLAN communication 200. In S <b> 11, the CPU 11 of the parent device 10 searches for the periphery by the WLAN communication control circuit 17 and detects an AP 51 existing in a range where WLAN communication is possible and a WLAN channel used by the AP 51. In the network of FIG. 3, the base unit 10 detects three APs 51 (51A, 51B, 51C) and the WLAN channels wch1, wch5, wch9 used by them.

  In S12, the CPU 11 of the parent device 10 transmits the channel information of the AP 51 detected in S11 to the nth child device n among the plurality of child devices. As described above, in the WLAN, the 2.4 GHz band is divided into 14 WLAN channels wch1 to wch14 (see FIG. 8). The ROM 12 of the base unit 10 stores a channel correspondence table as illustrated in FIG. 5 that associates each WLAN channel with a center frequency, a frequency range, and a DCL channel. For example, information on the center frequency of the WLAN channel used by the AP 51 out of wch1 to wch14 is transmitted. In the network of FIG. 3, the base unit 10 sends information on the center frequencies 2412 MHz, 2432 MHz, and 2452 MHz of the WLAN channels wch1, wch5, and wch9 used by each detected AP 51 (51A, 51B, 51C) to the slave units 61A to 61B. Send.

  In S <b> 13, the nth slave device n measures the radio field intensity of the center frequency of each WLAN channel included in the channel information received from the master device 10 by the DCL communication control circuit 62. At this time, in order to confirm the degree of influence received from the WLAN communication 200 performed by the parent device 10, the parent device 10 performs the WLAN communication 200 with the corresponding AP 51 in accordance with the measurement of the radio frequency intensity of the center frequency by the child device n. In the network of FIG. 3, the slave units 61 </ b> A to 61 </ b> B measure the radio field strengths of the center frequencies 2412 MHz, 2432 MHz, and 2452 MHz included in the channel information received from the master unit 10.

  In S14, the nth slave unit n arranges the center frequencies of the respective WLAN channels in order of decreasing radio wave intensity measured in S13. With reference to FIG. 6, the slave unit 61A will be specifically described as an example. FIG. 6 is a diagram showing a radio wave environment around the handset 61A in the network of FIG. Here, in general wireless communication, the frequency closer to the center of the band corresponding to the wireless channel is more frequently used for wireless communication. In addition, since the radio wave gradually attenuates as the distance from the transmission station increases, the radio wave intensity increases as the distance from the transmission station increases. Therefore, as shown in FIG. 6, the radio wave intensity around the slave unit 61A is centered on the center frequencies 2412 MHz, 2432 MHz, and 2452 MHz of the WLAN channels wch1, wch5, and wch9 used by each AP 51 (51A, 51B, 51C). The radio wave intensity of wch9 which is parabolic and used by the AP 51C farthest from the handset 61A is the weakest. As a result, the slave unit 61A arranges the center frequencies in the order of 2452 MHz → 2432 MHz → 2412 MHz.

  In S15, the CPU 11 of the parent device 10 determines whether or not n, which is the count value of the child device counter, is equal to the number of child devices. When n is not equal to the number of slave units (S15: NO), the CPU 11 of the master unit 10 adds 1 to n in S16 and returns to S12. On the other hand, when n is equal to the number of slave units (S15: YES), the CPU 11 of the master unit 10 ends the channel confirmation process. Thereby, in the network of FIG. 3 in which the multi-function device 1 includes a plurality of slave devices 61 (61A, 61B), the confirmation process of the WLAN channel used by the master device 10 for the WLAN communication 200 is performed for all the slave devices 61. . Further, this channel confirmation process is periodically performed.

  FIG. 7 shows a channel selection process at the time of incoming call of the multi-function device 1 in which the parent device 10 selects a WLAN channel to be used for the WLAN communication 200 when the child device 61 makes a call when receiving an incoming call from the telephone network 100. It is a flowchart to show. In S21, the CPU 11 of the base unit 10 performs a predetermined incoming call process by controlling the NCU 25 and the like. In S <b> 22, the arbitrary slave device X starts a call using the DCL communication 300 with the master device 10 based on a user operation. In S23, the slave device X transmits information on the center frequency of the WLAN channel with the weakest radio wave intensity to the master device 10 in accordance with the arrangement in S14 (see FIG. 4) of the channel confirmation process. In S24, the CPU 11 of the parent device 10 refers to the channel correspondence table (see FIG. 5) stored in the ROM 12, identifies the corresponding WLAN channel based on the center frequency information received from the child device X, The AP 51 that uses the specified WLAN channel is selected as the AP 51 that performs the WLAN communication 200.

  Here, a specific description will be given of an example in which the handset 61A in the network of FIG. As described above, the slave unit 61A arranges the center frequencies in the order of 2452 MHz → 2432 MHz → 2412 MHz in S14 of the channel confirmation process (see FIG. 4). Accordingly, the slave unit 61A transmits information of the center frequency 2452 MHz to the master unit 10 in S23. Therefore, in S24, base unit 10 specifies WLAN channel wch9 corresponding to the center frequency of 2452 MHz, and selects AP 51C that uses WLAN channel wch9. As a result, while the child device 61A makes a call, the parent device 10 performs the WLAN communication 200 with the AP 51C among the three APs 51 (51A, 51B, 51C).

  In S <b> 25, handset X ends the call by DCL communication 300 with base unit 10 based on the end of the user's conversation. In S <b> 26, the CPU 11 of the parent device 10 restores the selection of the AP 51 that performs the WLAN communication 200. Normally, base unit 10 selects AP 51 that uses the WLAN channel that receives the strongest radio wave by WLAN communication control circuit 17 as the optimal AP 51 for WLAN communication 200. In the network of FIG. 3, since the radio wave of the AP 51B closest to the parent device 10 is received most strongly, the parent device 10 normally selects the AP 51B. Therefore, in the network of FIG. 3, in S26, selection of the AP 51 that performs the WLAN communication 200 returns from the AP 51C to the original AP 51B.

Here, the correspondence with the claims is as follows.
The master device 10 is an example of a main communication device, the slave device 61 is an example of a sub communication device, the AP 51 is an example of an external communication device, and the multi-function device 1 is an example of a wireless communication device. The 2.4 GHz band is an example of a predetermined frequency band, the DCL channel is an example of a first wireless channel, the frequency hopping method is an example of a first wireless communication method, and the DCL communication control circuits 19 and 62 are first wireless communication means, respectively. The WLAN channel is an example of a second wireless channel, the direct spreading method is an example of a second wireless communication method, the WLAN communication control circuit 17 is an example of second wireless communication means, the radio wave intensity is an example of a radio wave state, and the SSID is a network It is an example of identification information. In addition, a selection means is realized by the channel confirmation processing (S11 to S16) and the incoming channel selection processing (S21 to S26) of the multi-function device 1. Further, S11 of the channel confirmation process is an example of detection means, and S13 is an example of measurement means.

  As described above in detail, according to the embodiment of the present invention, in the channel confirmation process of the multi-function device 1, the base unit 10 detects the WLAN channel used for the WLAN communication 200 (S11), and its center frequency. Is transmitted to the slave unit 61 (S12). The subunit | mobile_unit 61 measures the electromagnetic field intensity of the received center frequency (S13), and arranges a center frequency in order with a weak electromagnetic field intensity (S14). In the incoming channel selection process of the multi-function device 1, when the handset 61 starts a call (S22), it transmits information on the center frequency of the WLAN channel with the weakest radio field intensity to the base unit 10 (S23). Base unit 10 selects AP 51 based on the received center frequency information of the WLAN channel (S24). As a result, the base unit 10 normally performs the WLAN communication 200 with the AP 51 that is optimum for itself, and has the least influence on the DCL communication 300 with the handset 61 among the plurality of APs 51 while the handset 61 makes a call. WLAN communication 200 can be performed with the AP 51. In the infrastructure mode network in which the WLAN channel is determined by the AP 51, the base unit 10 can select the AP 51 that uses the WLAN channel that can avoid interference with the DCL communication 300 from the plurality of APs 51. As a result, the DCL communication 300 using the same 2.4 GHz band as the WLAN communication 200 can be performed while securing the necessary number of good channels.

  In addition, by measuring the radio field intensity of the center frequency that is frequently used, it is possible to shorten the measurement time and effectively avoid the use of a WLAN channel that has a high possibility of radio wave interference. Furthermore, since the detection of the WLAN channel is performed by the parent device 10, it is not necessary to provide the slave device 61 with a function for detecting the WLAN channel. Therefore, the structure of the subunit | mobile_unit 61 can be simplified and cost reduction can be achieved. In addition, since the channel confirmation process is periodically performed, it is possible to cope with changes in the surrounding radio wave environment due to movement of the slave unit 61 or the like.

Needless to say, the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention.
For example, each flowchart in the above embodiment is merely an example, and the process may be realized by another flowchart as long as a result equivalent to the process of each flowchart can be obtained.

  In the flowchart of the channel confirmation processing in FIG. 4, confirmation is performed for each slave unit 61 in order, but may be performed in parallel.

  The channel information is not limited to the center frequency information. The slave unit 61 may store a channel correspondence table and transmit the identification information of the WLAN channels wch1 to wch14 as channel information.

  The measurement of radio wave intensity is not limited to the center frequency, and other bands can be measured. Furthermore, besides measuring the radio field intensity, BER (Bit Error Rate) or the like may be measured.

  In the incoming channel selection process of FIG. 7, the channel selection process at the incoming time from the telephone network 100 has been described, but the present invention is not limited to this. It goes without saying that the same effect can be obtained even when applied to a call to the telephone line network 100, an extension call between the master unit 10 and the slave unit 61, or the like.

In the above-described embodiment, the WLAN function is mounted only on the parent device 10, but is not limited thereto. A WLAN function may be mounted on the slave unit 61 together with the master unit 10.
In this case, base unit 10 searches for the periphery and detects AP 51 capable of WLAN communication and its WLAN channel. The base unit 10 normally performs the WLAN communication 200 with the AP 51 optimum for the base unit 10 itself among the detected APs 51.
On the other hand, the handset 61 also searches the periphery and detects the AP 51 capable of WLAN communication and its WLAN channel. The slave unit 61 determines the AP 51 that is optimal for the slave unit 61 among the detected APs 51, that is, has the least influence on the DCL communication 300, and notifies the master unit 10 of the AP 51.
Then, the parent device 10 performs the WLAN communication 200 with the AP 51 that is optimal for the child device 61 and has the least effect on the DCL communication 300, while the child device 61 makes a call, not the optimum AP 51 for the parent device 10 itself. .
By installing the WLAN function in the slave unit 61, the slave unit 61 incurs a cost for mounting the WLAN function. However, based on the SSID, the AP 51 belonging to the in-house network 500 and the APs belonging to other networks are connected. Can be identified. Therefore, the slave unit 61 can determine APs belonging to other networks in which there is no change in communication load associated with the WLAN communication 200 of the master unit 10. Therefore, even if there is an AP belonging to another network in the vicinity, the slave unit 61 accurately grasps only the AP 51 related to the WLAN communication 200 of the master unit 10 and transmits it to the master unit 10. The optimum AP 51 for the slave unit 61 can be selected.

1 Multi-function device 10 Base device 17 WLAN communication control circuit 19, 62 DCL communication control circuit 51 Access point (AP)
61 Child machine

Claims (7)

In a wireless communication device comprising a main communication device and at least one sub communication device, performing wireless communication between the main and sub communication devices and performing wireless communication with a plurality of external communication devices,
While using one of a plurality of first radio channels provided in a predetermined frequency band, the first and second communication devices are switched between the main and sub communication devices by a first radio communication system that switches the first radio channel to be used at a predetermined cycle. First wireless communication means for performing wireless communication;
The external communication by a second wireless communication system that continuously uses a second wireless channel having a wider bandwidth than the first wireless channel provided in the predetermined frequency band used by the first wireless communication means. Second wireless communication means for performing wireless communication with the apparatus;
When both the first wireless communication unit and the second wireless communication unit perform wireless communication, an external communication device that has less influence on wireless communication by the first wireless communication unit is transferred from the plurality of external communication devices. And a selection means for selecting,
The second wireless communication unit performs wireless communication with the external communication device selected by the selection unit when performing wireless communication simultaneously with the first wireless communication unit. The selecting means is
Detecting means for detecting an external communication device capable of wireless communication by the second wireless communication means and a second wireless channel used for wireless communication with the external communication device;
Measuring means for measuring the radio wave condition of the second wireless channel detected by the detecting means,
The wireless communication device according to claim 1, wherein the external communication device is selected based on a radio wave state measured by the measuring means. The measurement means measures the intensity of the radio wave received in the band corresponding to the second radio channel as the radio wave state of the second radio channel,
The selecting means selects an external communication device that uses the second wireless channel having a weak radio wave intensity measured by the measuring means as an external communication device that has little influence on the wireless communication by the first wireless communication means. The wireless communication apparatus according to claim 2. 4. The wireless communication according to claim 3, wherein the measurement unit measures the intensity of a radio wave received at a center frequency of a band corresponding to the second radio channel as a radio wave state of the second radio channel. apparatus. The detection means is mounted on the main communication device,
The wireless communication device according to claim 2, wherein the measurement unit is mounted on the sub communication device. The detection means periodically detects,
The wireless communication apparatus according to claim 2, wherein the measurement unit performs measurement periodically. The main communication device is a base unit of a digital cordless phone,
The sub-communication device is a handset of the digital cordless telephone;
The first wireless communication means is a digital cordless telephone system;
The second wireless communication means is a wireless LAN system;
The wireless communication device according to any one of claims 1 to 6, wherein the external communication device is an access point having the same network identification information in the wireless LAN.

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