JP6016667B2 - Communication apparatus and computer program - Google Patents

Description

  The present invention relates to a technology for suppressing interference between different types of wireless communication.

  As a technology for suppressing interference between different types of wireless communication, one wireless communication is performed in a terminal device that performs wireless communication based on IEEE802.11 standard and wireless communication based on Bluetooth (registered trademark). Sometimes a technique for suppressing the other wireless communication (or transmission of the other wireless communication) (for example, Patent Document 1), or when performing wireless LAN transmission, Bluetooth only performs reception and Bluetooth reception A technique for canceling a wireless LAN transmission signal from a signal (for example, Patent Document 2) is known.

Japanese Patent Laid-Open No. 2001-24579 JP 2007-142684 A

  In the terminal device that performs wireless communication by wireless LAN based on IEEE802.11 standard and wireless communication by Bluetooth as described above, when one wireless communication (or transmission of one wireless communication) is performed, the other wireless communication (or According to the technology for suppressing the transmission of the other wireless communication), it becomes impossible to perform transmission and reception of the two wireless communications in parallel, and as a result, a communication usage source that performs processing using wireless communication. However, there are significant disadvantages for communication users, such as being unable to perform required communications.

  Accordingly, an object of the present invention is to effectively suppress interference interference in a communication apparatus that performs communication using different wireless communication methods in a form that has less disadvantage of the communication use source.

  In order to achieve the above object, the present invention dynamically selects a maximum transmission rate that can ensure normal transmission from a plurality of transmission rates defined in advance as a set transmission rate, and performs transmission at the set transmission rate. A communication device that performs transmission using two different wireless communication methods, namely, a first wireless communication method to be performed and a second wireless communication method that uses a frequency band overlapping with the first communication method for transmission. A deterioration detecting unit for detecting deterioration of reception quality of transmission of the second wireless communication method to a predetermined level or less when transmission of the second wireless communication method and transmission of the second wireless communication method are performed simultaneously; and the deterioration detection And a transmission power control unit configured to reduce transmission power of transmission of the first wireless communication system when the means detects the deterioration. However, the transmission power control unit selects, as a target transmission rate, one transmission rate smaller than the currently set transmission rate among the plurality of predefined transmission rates, and the first wireless communication method The difference between the sensitivity required for normal reception of transmission at the current set transmission rate and the sensitivity required for normal reception of transmission at the target transmission rate of the first wireless communication system is calculated as a required sensitivity difference. The calculated required sensitivity difference and the transmission power of the transmission of the wireless communication system of 1 are reduced.

  Here, such a communication apparatus is configured such that, in the transmission power control unit, according to the minimum reception sensitivity defined for each of the plurality of transmission rates defined in advance in the standard defining the first wireless communication method. The difference between the minimum reception sensitivity specified for the current set transmission rate and the minimum reception sensitivity specified for the target transmission rate is calculated as the required sensitivity difference. May be.

  According to such a communication apparatus, the transmission by the second wireless communication method can be performed only by reducing the transmission speed of the transmission by the first wireless communication method without stopping the transmission by the transmission by the first wireless communication method. Can be suppressed. Further, the transmission power of the transmission of the first wireless communication method is reduced by the maximum reduction amount with respect to the reduction rate of the transmission speed of the transmission of the first wireless communication method, and the transmission of the transmission by the second wireless communication method is received. Disability can be suppressed. Therefore, it is possible to effectively suppress the occurrence of reception failure in the transmission by the second wireless communication method while suppressing the disadvantage to the communication source performing the communication using the transmission of the first wireless communication method. Will be able to.

  Further, the communication device as described above has a transmission speed lower than the current set transmission speed among the plurality of transmission speeds defined in advance in the transmission power control unit, and is lower than the set transmission speed. You may comprise so that the largest transmission rate may be selected as said target transmission rate among transmission rates.

By doing so, it is possible to suppress the occurrence of a reception failure in the transmission by the second wireless communication system while minimizing the decrease in the transmission speed of the transmission of the first wireless communication system.
Further, the communication apparatus as described above calculates, in the transmission power control unit, a transmission rate necessary for communication performed using transmission of the first wireless communication method as a required transmission rate, You may make it select the minimum transmission rate more than the said required transmission rate among the prescribed | regulated transmission rates as said target transmission rate.

  Alternatively, in the transmission power control unit, communication using the transmission of the first wireless communication method is performed via a mobile communication service by another device that performs transmission of the first wireless communication method with the communication device. When the communication is relayed to the mobile communication network, the maximum transmission rate of the mobile communication provided by the mobile communication service is calculated as the required transmission rate, and the required transmission rate is selected from the plurality of predetermined transmission rates. A minimum transmission speed equal to or higher than the transmission speed may be selected as the target transmission speed. In this case, the communication device is provided with a current position calculation unit that calculates the current position of the communication device, and the transmission power control unit moves the mobile device in an area to which the current position calculated by the current position calculation unit belongs. The maximum transmission rate of mobile communication provided by the communication service may be calculated as the required transmission rate.

  Alternatively, in the transmission power control unit, when the communication using the transmission of the first wireless communication method is to transmit / receive audio data or video data to be reproduced in real time, the bit of the audio data or video data The rate may be calculated as the required transmission rate, and the minimum transmission rate that is equal to or higher than the required transmission rate among the plurality of predefined transmission rates may be selected as the target transmission rate.

  By doing so, within the range in which the transmission rate higher than the transmission rate necessary for the communication using the transmission of the first wireless communication method is maintained, the maximum width, the transmission of the wireless communication method of the first wireless communication method is maintained. By reducing the transmission power, it is possible to suppress a reception failure in transmission by the second wireless communication method. Therefore, it is possible to effectively suppress the occurrence of a reception failure in the transmission by the second wireless communication method without detriment to the communication source performing the communication using the transmission of the first wireless communication method. Become.

  Here, in the above communication apparatus, the first wireless communication method is, for example, a wireless LAN wireless communication method defined in the IEEE802.11b or IEEE802.11g standard using the 2.4 MHz band for transmission. The second wireless communication method can be, for example, a wireless communication method defined by the Bluetooth standard.

  Further, the above communication device may be mounted on an automobile.

  As described above, according to the present invention, interference interference can be effectively suppressed in a communication apparatus that performs communication using different wireless communication schemes in a form in which there are fewer disadvantages of the communication user.

It is a block diagram which shows the structure of the vehicle-mounted apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the interference failure which may generate | occur | produce with the vehicle-mounted apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which shows the transmission power control process which concerns on 1st Embodiment of this invention. It is a figure which shows the transmission rate and minimum receiving sensitivity which are prescribed | regulated by the IEEE802.11g standard. It is a flowchart which shows the transmission power control process which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the required communication speed calculation process which concerns on 2nd Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described taking application to an in-vehicle device mounted on an automobile as an example.
First, the first embodiment will be described.
In FIG. 1, the structure of the vehicle-mounted apparatus which concerns on this 1st Embodiment is shown.
As shown in the figure, the in-vehicle device 1 includes a wireless LAN interface device 11 that transmits and receives wireless signals via a wireless LAN interface that conforms to the IEEE802.11g standard, and a BT communication that transmits and receives wireless signals via a wireless communication interface that conforms to the Bluetooth standard. A device 12, an operating system 13, and a plurality of applications that are managed by the operating system 13 and run on the operating system 13.

  The operating system 13 also includes a wireless LAN driver 131 that controls the wireless LAN interface device 11 to provide a communication function using a wireless LAN, and a BT that controls a BT communication device 12 and provides a communication function using Bluetooth. A communication driver 132 and a transmission power control unit 133 are incorporated.

  For a plurality of applications running on the operating system 13, a wireless LAN utilization application that is a wireless LAN utilization communication that is a communication via the wireless LAN using a communication function provided by the wireless LAN driver 131. 14, a BT communication utilization application 15 that performs BT utilization communication that is communication via Bluetooth using a communication function provided by the BT communication driver 132, and other applications 16.

  Here, as a device in which the wireless LAN interface device 11 of the in-vehicle device 1 transmits / receives a wireless signal, there is the wireless LAN router 2 shown in the drawing. The wireless LAN router 2 is connected to a base station 31 of the mobile telephone network 3 that provides an Internet connection service by mobile communication, and performs tethering for relaying communication between the wireless LAN and the Internet 4. And the wireless LAN utilization application 14 of the vehicle-mounted apparatus 1 is an application which performs the above-mentioned wireless LAN utilization communication with the server 5 etc. on the internet 4 using the tethering of such a wireless LAN router 2, for example.

The wireless LAN router 2 may be built in a smartphone, a mobile phone, or the like.
On the other hand, as a device in which the BT communication device 12 of the in-vehicle device 1 transmits and receives a wireless signal, there is a portable player 6 having a Bluetooth communication function for reproducing recorded audio data and video data. Then, the BT communication utilization application 15 of the in-vehicle device 1 performs, for example, real-time reproduction in which audio data and video data transferred from the portable player 6 are reproduced and output in parallel with the transfer by the above-described BT utilization communication. It is an application to perform.

  Now, the IEEE802.11g standard and the Bluetooth standard both use the 2.4 GHz band (ISM band) frequency, and both are different wireless communication standards that mediate interference interference between the two. There is no mechanism for each standard. For this reason, a failure due to interference may occur between transmission / reception of the wireless signal performed by the in-vehicle device 1 via the wireless LAN interface and transmission / reception of the wireless signal performed via the Bluetooth interface.

That is, for example, as shown in FIG. 2 a 1, a case where the in-vehicle device 1 transmits and receives wireless signals with the wireless LAN router 2 and the wireless LAN interface, and the in-vehicle device 1 transmits and receives wireless signals with the portable player 6 and the Bluetooth interface. Think.
In the following description, a wireless signal transmitted / received through the wireless LAN interface is described as a “wireless LAN signal”, and a wireless signal transmitted / received through the Bluetooth interface is described as a “BT signal”.
Now, in the case shown in FIG. 2a1, a BT signal which is a frequency band used for transmission / reception of a BT signal is a wireless LAN signal band which is a frequency band used for transmission / reception of a wireless LAN signal by control stipulated in each standard. A certain frequency difference ΔF is set between the bands so that they do not overlap.
In this case, the wireless LAN signal transmitted by the wireless LAN interface device 11 of the in-vehicle device 1 is received as noise by the BT communication device 12 of the in-vehicle device 1.
As shown in FIG. 2 b 1, when the strength 202 of the BT signal received by the BT communication device 12 and the strength 201 of the wireless LAN signal received as noise by the BT communication device 12 are the same strength, Since the BT signal is received by the BT communication device 12 with a sufficient S / N ratio, the BT communication device 12 does not cause a reception failure of the BT signal due to interference. In FIG. 2b1, ΔI represents the difference between the strength 202 of the BT signal received by the BT communication device 12 and the wireless LAN signal strength 201 received as noise by the BT communication device 12.

  On the other hand, as shown in FIG. 2a2, for example, when the distance from the in-vehicle device 1 to the portable player 6 through which the in-vehicle device 1 transmits and receives the BT signal is large, the strength 202 of the BT signal received by the BT communication device 12 is Therefore, the ratio of the strength 201 of the wireless LAN signal received as noise in the BT communication device 12 to the strength 202 of the BT signal received by the BT communication device 12 is increased, and the SN ratio is deteriorated. The device 12 cannot receive the BT signal normally. As described above, the wireless LAN signal mixed as noise with high intensity in the BT signal received by the in-vehicle device 1 is only the wireless LAN signal transmitted by the in-vehicle device 1 itself, and the wireless LAN signal separated from the in-vehicle device 1 is used. It is rare that the wireless LAN signal transmitted by the router 2 is mixed in the BT signal received by the BT communication device 12 as noise with a large intensity.

Hereinafter, a transmission power control process performed by the transmission power control unit 133 of the operating system 13 of the in-vehicle device 1 in order to suppress the occurrence of the failure due to the interference in the in-vehicle device 1 will be described.
FIG. 3 shows the procedure of this transmission power control process.
As shown in the figure, in this process, first, the communication execution state of each driver is acquired from the wireless LAN driver 131 and the BT communication driver 132 to determine whether both wireless LAN utilization communication and BT utilization communication are being executed. (Step 302).
If both the wireless LAN utilization communication and the BT utilization communication are not being executed (step 302), the wireless LAN driver 131 sets the transmission power of the wireless LAN signal of the wireless LAN interface device 11 to a predetermined standard value. (Step 314), the process returns to Step 302.

  On the other hand, if both the wireless LAN utilization communication and the BT utilization communication are being executed (step 302), it is checked whether or not the reception quality of the BT signal in the BT communication apparatus 12 is less than a predetermined threshold Th ( Step 304). Here, the reception quality of the BT signal includes the error occurrence rate of the BT signal received by the BT communication device 12, the SN ratio of the BT signal received by the BT communication device 12, the reception strength of the BT signal in the BT communication device 12, and the like. Is obtained from the BT communication driver 132 and calculated. Here, if the reception quality is equal to or higher than the threshold value Th, a value that can guarantee normal reception of the BT signal is set.

If the reception quality of the BT signal is not less than the predetermined threshold Th (step 304), the processing returns to step 302.
On the other hand, if the reception quality of the BT signal is less than the predetermined threshold Th (step 304), the wireless LAN signal transmission rate in the wireless LAN interface device 11 is acquired from the wireless LAN driver 131 (step 306). Then, it is checked whether or not the transmission speed of the acquired wireless LAN signal is set to the minimum of transmission speeds that can be set as the transmission speed of the wireless LAN signal (step 308).

  Here, the wireless LAN interface apparatus 11 according to the IEEE802.11g standard can set 12 transmission speeds set between 6 Mbps and 54 Mbps shown in FIG. 4 as the transmission speed of the wireless LAN signal. In addition, the IEEE802.11g standard stipulates the minimum receiver sensitivity (Receiver Minimum Input Level Sensitivity) shown for each transmission rate, and a device that receives a wireless LAN signal receives a wireless signal at each transmission rate. Therefore, it is possible to perform the reception with better reception sensitivity than the minimum reception sensitivity defined for the transmission speed.

Returning to FIG. 3, if the transmission speed of the wireless LAN signal is set to the minimum transmission speed that can be set as the transmission speed of the wireless LAN signal (step 308), the processing returns to step 302.
On the other hand, if the transmission speed of the wireless LAN signal is not set to the minimum transmission speed that can be set as the transmission speed of the wireless LAN signal, the transmission speed currently set is shown in FIG. The difference between the minimum reception sensitivity specified in FIG. 4 and the minimum reception sensitivity specified as shown in FIG. 4 for a transmission speed that is one smaller than the currently set transmission speed is the minimum reception sensitivity difference. (Step 310).

  That is, for example, if the currently set transmission rate is 48 Mbps, the one-step lower transmission rate is 36 Mbps, so -66 dBm specified for 48 Mbps and -70 dBm specified for 36 Mbps And 4dB is obtained as the minimum reception sensitivity difference.

Then, the transmission power of the wireless LAN signal of the wireless LAN interface apparatus 11 is decreased from the current magnitude of the transmission power (step 312), and the process returns to step 302.
Now, other devices such as the wireless LAN interface device that has reduced the transmission power of the wireless LAN signal and the wireless LAN router 2 that transmits and receives the wireless LAN signal to and from the wireless LAN interface device 11 are IEEE802.11g. The speed at which the transmission speed of the wireless LAN signal can be automatically transmitted at a predetermined quality or higher when the wireless LAN signal cannot be maintained at a predetermined quality or higher by the control according to the standard. To fall.

As a result, in a state where normal transmission can be performed at a certain transmission speed X, the minimum reception sensitivity defined for the transmission speed X in the IEEE802.11g standard and the transmission speed Y (Y <X). Even if the transmission rate X cannot be normally transmitted because the transmission power is reduced, the decrease in the reception level on the receiving side of the wireless LAN signal is proportional to the decrease in the transmission power. At least transmission at the transmission rate Y is normally performed.
That is, for example, in a state where normal transmission can be performed at 48 Mbps, the difference between -66 dBm specified for 48 Mbps in the IEEE802.11g standard and -70 dBm specified for 36 Mbps, 4 dB transmission power Even if the value is reduced, 36 Mbps transmission can be performed normally.
On the other hand, due to a decrease in the transmission power of the wireless LAN signal, the strength of the wireless LAN signal received as noise by the BT communication device 12 is reduced relative to the strength of the BT signal received by the BT communication device 12.
According to the above transmission power control process, the transmission power of the wireless LAN signal is sequentially decreased step by step until the reception quality of the BT signal becomes equal to or higher than the threshold value Th. Due to the decrease, it is possible to eliminate the BT signal reception failure caused by the interference in the BT communication device 12.

The transmission power control process performed by the transmission power control unit 133 has been described above.
The first embodiment of the present invention has been described above.
As described above, according to the first embodiment, within the range in which the transmission rate is reduced only by one step, the maximum width and the transmission power of the wireless LAN signal are only increased until the reception quality of the BT communication device 12 is restored. By gradually decreasing, reception failure due to interference of the BT communication device 12 is suppressed. Therefore, it is possible to avoid the occurrence of a reception failure of the BT communication device 12 with the maximum effect on the reduction rate of the transmission rate. In addition, it is possible to effectively avoid the occurrence of a reception failure of the BT communication device 12 while performing transmission / reception of wireless LAN utilization communication at the highest possible transmission speed in parallel with transmission / reception of BT utilization communication.

Hereinafter, a second embodiment of the present invention will be described.
In the second embodiment, the transmission power control process shown in FIG. 3 performed by the transmission power control unit 133 in the first embodiment described above is replaced with the transmission power control process shown in FIG.
That is, as shown in FIG. 5, in the second embodiment, the transmission power control unit 133 first determines whether both wireless LAN utilization communication and BT utilization communication are being executed in the transmission power control process. (Step 502).
If both the wireless LAN utilization communication and the BT utilization communication are not being executed (step 502), the wireless LAN driver 131 sets the transmission power of the wireless LAN signal of the wireless LAN interface device 11 to a predetermined standard value. (Step 516), the process returns to Step 502.

On the other hand, if both the wireless LAN utilization communication and the BT utilization communication are being executed (step 502), it is checked whether or not the reception quality of the BT signal in the BT communication apparatus 12 is less than a predetermined threshold Th ( Step 504).
If the reception quality of the BT signal is not less than the predetermined threshold Th (step 504), the process returns to step 502.
On the other hand, if the reception quality of the BT signal is less than the predetermined threshold Th (step 504), the transmission speed of the wireless LAN signal is acquired from the wireless LAN driver 131 (step 506). Then, it is checked whether or not the acquired transmission rate is set to the minimum of the transmission rates that can be set as the transmission rate of the wireless LAN signal shown in FIG. 4 (step 508).

If the transmission speed of the wireless LAN signal is set to the minimum transmission speed that can be set as the transmission speed of the wireless LAN signal (step 508), the processing returns to step 502.
On the other hand, if the transmission speed of the wireless LAN signal is not set to the minimum transmission speed that can be set as the transmission speed of the wireless LAN signal, a required communication speed calculation process, which will be described in detail later, is performed, and the wireless LAN signal is transmitted. The transmission speed of the wireless LAN signal necessary for the wireless LAN utilization communication performed by the utilization application 14 is calculated as the required communication speed (step 510).

  Then, as shown in FIG. 4, the minimum reception sensitivity defined as shown in FIG. 4 with respect to the currently set wireless LAN signal transmission speed and the minimum transmission speed above the required communication speed. The difference from the minimum reception sensitivity specified in the above is obtained as the minimum reception sensitivity difference (step 512).

  That is, for example, if the currently set transmission rate is 54 Mbps and the minimum transmission rate above the required communication rate is 10 Mbps, -65 dBm specified for 54 Mbps and the minimum of 10 Mbps or more The difference from -79 dBm specified for 12 Mbps, which is the specified transmission rate, and 14 dB are obtained as the minimum receiving sensitivity difference.

Then, the transmission power of the wireless LAN signal of the wireless LAN interface device 11 is decreased from the current magnitude of the transmission power, and the obtained minimum reception sensitivity difference is decreased (step 514), and the processing returns to step 502.
Here, as described above, other devices such as the wireless LAN interface device with reduced wireless LAN signal transmission power and the wireless LAN router 2 that transmits and receives wireless LAN signals to and from the wireless LAN interface device 11 are IEEE802.11g. The speed at which the transmission speed of the wireless LAN signal can be automatically transmitted at a predetermined quality or higher when the wireless LAN signal cannot be maintained at a predetermined quality or higher by the control according to the standard. To fall.

As a result, in a state where normal transmission can be performed at a certain transmission speed X, the minimum reception sensitivity defined for the transmission speed X in the IEEE802.11g standard and the transmission speed Y (Y <X). Even if the transmission power of the wireless LAN signal cannot be normally transmitted because the transmission power of the wireless LAN signal is decreased, the decrease in the reception level on the reception side of the wireless LAN signal causes the transmission power to decrease. Therefore, transmission at a transmission speed at least equal to or higher than the transmission speed Y is normally performed.
That is, for example, in a state where normal transmission can be performed at 54 Mbps, the difference between -65 dBm specified for 54 Mbps in the IEEE 802.11g standard and -79 dBm specified for 12 Mbps, 14 dB transmission power Even if it decreases, transmission at a transmission speed of 12 Mbps or more can be performed normally.
On the other hand, due to the decrease in the transmission power of the wireless LAN signal, the strength of the wireless LAN signal received as noise in the BT communication device 12 is reduced relative to the strength of the BT signal received in the BT communication device 12 by the decrease. It becomes.

The transmission power control process performed by the transmission power control unit 133 has been described above in the second embodiment.
Next, the required communication rate calculation process performed by the transmission power control unit 133 in step 510 of the transmission power control process of FIG. 5 according to the second embodiment will be described.
FIG. 6 shows the procedure of the required communication speed calculation process.
As shown in the figure, in the required communication speed calculation process, first, the wireless LAN utilization application 14 that performs wireless LAN utilization communication is specified (step 602). Here, the wireless LAN using application 14 is specified by using a wireless LAN driver 131 or an application that performs communication from the operating system 13 via the wireless LAN driver 131, that is, a communication port that transmits and receives signals with the wireless LAN driver 131. This can be done by obtaining the identification of the application that is being used.

  Next, it is determined whether or not the wireless LAN utilization communication performed by the wireless LAN utilization application 14 identified in step 602 communicates with the Internet 4 using tethering of the wireless LAN router 2 (step 604). . Here, in this determination, the address of the communication partner of the wireless LAN utilization communication performed by the wireless LAN utilization application 14 is acquired from the wireless LAN driver 131 or the operating system 13, and the acquired address is an address outside the wireless LAN. In this case, it can be performed by determining that the wireless LAN utilization communication performed by the wireless LAN utilization application 14 communicates with the Internet 4. However, when the wireless LAN utilization application 14 performing wireless LAN utilization communication is an application specialized for Internet utilization such as an Internet browser, the wireless LAN utilization communication performed unconditionally by the wireless LAN utilization application 14 May be determined to communicate with the Internet 4.

  If it is determined that the wireless LAN utilization communication performed by the wireless LAN utilization application 14 is communication with the Internet 4 (step 604), the wireless LAN interface device 11 transmits and receives wireless LAN signals. The maximum transmission rate of mobile communication provided by the service of the mobile communication carrier used by the LAN router 2 is calculated as the required communication rate (step 610), and the required communication rate calculation process is terminated. Here, since the transmission speed of the wireless LAN is larger than the maximum transmission speed of a general mobile communication service, the bottleneck of communication using the wireless LAN for communicating with the Internet 4 is mobile communication. Therefore, even if the transmission speed of the wireless LAN is reduced within a range equal to or higher than the maximum transmission speed of mobile communication, there is no problem in the wireless LAN utilization communication performed by the wireless LAN utilization application 14.

  Here, the maximum transmission rate of mobile communication provided by the service of the mobile communication carrier used by the wireless LAN router 2 is set in the transmission power control unit 133 in advance. Alternatively, when the in-vehicle device 1 includes a function unit that calculates a current position, such as a GPS receiver or a navigation application, each area set in advance and movement used by the wireless LAN router 2 in the area According to the correspondence with the maximum transmission rate of the mobile communication provided by the service of the communication carrier, the maximum transmission rate corresponding to the area to which the calculated current position belongs is calculated as the maximum transmission rate of the mobile communication performed by the wireless LAN router 2. May be.

  On the other hand, if the wireless LAN utilization communication performed by the wireless LAN utilization application 14 does not communicate with the Internet 4, the wireless LAN utilization communication performed by the wireless LAN utilization application 14 is reproduced in real time by the wireless LAN utilization application 14. It is determined whether audio data or video data is to be transferred (step 606). Here, this determination is made by inquiring to the wireless LAN utilization application 14 that is performing wireless LAN utilization communication whether or not the use of the wireless LAN utilization communication is real-time reproduction.

  If the wireless LAN utilization communication performed by the wireless LAN utilization application 14 transfers audio data and video data to be reproduced in real time in the wireless LAN utilization application 14 (step 606), the audio data and video to be reproduced in real time. The data bit rate is obtained by inquiring of the wireless LAN using application 14, the obtained bit rate is calculated as the required communication speed (step 612), and the required communication speed calculation process is terminated.

  On the other hand, if the wireless LAN utilization communication performed by the wireless LAN utilization application 14 does not transfer audio data or video data to be reproduced in real time in the wireless LAN utilization application 14 (step 606), the wireless LAN illustrated in FIG. The minimum transmission speed among the 12 transmission speeds that can be set as the transmission speed of the signal is calculated as the required communication speed (step 608), and the required communication speed calculation processing is terminated.

Heretofore, the required communication speed calculation process performed by the transmission power control unit 133 in Step 510 of the transmission power control process of FIG. 5 has been described.
As described above, according to the second embodiment, the maximum width and the wireless LAN signal are within the range in which the transmission rate higher than the transmission rate necessary for the wireless LAN utilization communication performed by the wireless LAN utilization application 14 is maintained. It is possible to reduce the transmission power and suppress the reception failure due to the interference of the BT communication device 12. Therefore, the reception failure of the BT communication apparatus 12 can be effectively suppressed without any disadvantage for the wireless LAN utilization communication application.

   In the above, the case where the in-vehicle device 1 performs the communication between IEEE802.11g and Bluetooth has been described. However, in the in-vehicle device 1, instead of IEEE802.11g or together with IEEE802.11g, the 2.4 MHz band is used. The same can be applied to the case of performing IEEE802.11b or IEEE802.11n communication using.

  In addition, in the case of performing communication in any combination of communication schemes in which two different frequency bands overlap other than the combination of IEEE802.11g, IEEE802.11b, IEEE802.11n and Bluetooth, there are a plurality of communication schemes. The present embodiment can be similarly applied to a communication method that can be used by switching the transmission speed of the communication method.

  In the above description, the application to the in-vehicle device 1 has been described as an example. However, in the present embodiment, any device that performs communication using a communication method in which two different frequency bands overlap, for example, IEEE802.11b / g and Bluetooth. The present invention can be similarly applied to smartphones, mobile phones, PDAs, personal computers, and tablet computers that perform both communications.

  DESCRIPTION OF SYMBOLS 1 ... In-vehicle apparatus, 2 ... Wireless LAN router, 3 ... Mobile telephone network, 4 ... Internet, 5 ... Server, 6 ... Portable player, 11 ... Wireless LAN interface apparatus, 12 ... BT communication apparatus, 13 ... Operating system, 14 ... Wireless LAN application, 15 ... BT communication application, 31 ... base station, 131 ... wireless LAN driver, 132 ... BT communication driver, 133 ... transmission power controller.

Claims (20)

A first wireless communication system that dynamically selects a maximum transmission rate capable of ensuring normal transmission from a plurality of predefined transmission rates as a set transmission rate and performs transmission at the set transmission rate; A communication device that performs transmission using two different wireless communication methods, a second wireless communication method that uses a frequency band that overlaps the first wireless communication method for transmission,
A degradation detector that detects degradation of reception quality of transmission of the second wireless communication system to a predetermined level or less when transmission of the first wireless communication system and transmission of the second wireless communication system are performed simultaneously. When,
A transmission power control unit that reduces transmission power of transmission of the first wireless communication method when the deterioration detection unit detects the deterioration;
The transmission power control unit
A transmission rate smaller than the currently set transmission rate is selected as a target transmission rate among the plurality of transmission rates defined in advance,
Sensitivity required for normal reception of transmission at the current set transmission rate of the first wireless communication method and sensitivity required for normal reception of transmission at the target transmission rate of the first wireless communication method. A communication apparatus characterized in that the difference is calculated as a required sensitivity difference, and the calculated required sensitivity difference and transmission power of transmission of the first wireless communication system are reduced. The communication device according to claim 1,
The transmission power control unit is configured for the current set transmission rate in accordance with a minimum reception sensitivity defined for each of the plurality of transmission rates defined in advance in the standard defining the first wireless communication method. And calculating the difference between the minimum reception sensitivity specified for the target transmission speed and the minimum reception sensitivity specified for the target transmission rate as the required sensitivity difference. The communication device according to claim 1 or 2,
The transmission power control unit is a transmission rate less than the current set transmission rate among the plurality of predefined transmission rates, and a maximum transmission rate among transmission rates less than the set transmission rate. The communication apparatus is selected as the target transmission rate. The communication device according to claim 1 or 2,
The transmission power control unit calculates a transmission rate required for communication performed using the transmission of the first wireless communication method as a required transmission rate, and among the plurality of transmission rates defined in advance, The communication apparatus is characterized in that a transmission speed that is minimum above the required transmission speed is selected as the target transmission speed. The communication device according to claim 1 or 2,
The transmission power control unit is configured such that communication using the transmission of the first wireless communication method is moved via a mobile communication service by another device performing transmission of the first wireless communication method with the communication device. When the communication is relayed to the communication network, the maximum transmission rate of the mobile communication provided by the mobile communication service is calculated as the required transmission rate, and the required transmission rate of the plurality of predefined transmission rates is calculated. A communication apparatus, wherein the minimum transmission rate is selected as the target transmission rate. The communication device according to claim 5,
It has a current position calculation unit that calculates the current position of the communication device,
The transmission power control unit calculates a maximum transmission rate of mobile communication provided by the mobile communication service as the required transmission rate in an area to which the current location calculated by the current location calculation unit belongs. The communication device according to claim 1 or 2,
The transmission power control unit sets the bit rate of the audio data or video data when the communication using the transmission of the first wireless communication method is to transmit or receive audio data or video data to be reproduced in real time. A communication apparatus that calculates as a required transmission rate and selects, as the target transmission rate, a minimum transmission rate that is equal to or higher than the required transmission rate among the plurality of predetermined transmission rates. The communication device according to claim 1, 2, 3, 4, 5, 6 or 7,
The first wireless communication system is a wireless LAN wireless communication system defined by the IEEE802.11b or IEEE802.11g standard using the 2.4 MHz band for transmission. The communication device according to claim 8,
The communication apparatus characterized in that the second wireless communication system is a wireless communication system defined by the Bluetooth standard. The communication device according to claim 1, 2, 3, 4, 5, 6, 7, 8, or 9,
The communication device is mounted on an automobile. A first wireless communication system that dynamically selects a maximum transmission rate capable of ensuring normal transmission from a plurality of predefined transmission rates as a set transmission rate and performs transmission at the set transmission rate; A computer program that is read and executed by a computer that performs transmission using two different wireless communication methods, the second wireless communication method using a frequency band overlapping with the first wireless communication method .
The computer program stores the computer,
A degradation detector that detects degradation of reception quality of transmission of the second wireless communication system to a predetermined level or less when transmission of the first wireless communication system and transmission of the second wireless communication system are performed simultaneously. When,
When the deterioration detection unit detects the deterioration, function as a transmission power control unit to reduce the transmission power of the transmission of the first wireless communication system,
The transmission power control unit
A transmission rate smaller than the currently set transmission rate is selected as a target transmission rate among the plurality of transmission rates defined in advance,
Sensitivity required for normal reception of transmission at the current set transmission rate of the first wireless communication method and sensitivity required for normal reception of transmission at the target transmission rate of the first wireless communication method. A computer program characterized in that the difference is calculated as a required sensitivity difference, and the calculated required sensitivity difference and transmission power of transmission in the first wireless communication system are reduced. A computer program according to claim 11, comprising:
The transmission power control unit is configured for the current set transmission rate in accordance with a minimum reception sensitivity defined for each of the plurality of transmission rates defined in advance in the standard defining the first wireless communication method. A computer program for calculating a difference between a minimum receiving sensitivity specified in the above and a minimum receiving sensitivity specified for the target transmission rate as the required sensitivity difference. A computer program according to claim 11 or 12, comprising:
The transmission power control unit is a transmission rate less than the current set transmission rate among the plurality of predefined transmission rates, and a maximum transmission rate among transmission rates less than the set transmission rate. A computer program selected as the target transmission rate. A computer program according to claim 11 or 12, comprising:
The transmission power control unit calculates a transmission rate required for communication performed using the transmission of the first wireless communication method as a required transmission rate, and among the plurality of transmission rates defined in advance, A computer program that selects a transmission rate that is minimum above the required transmission rate as the target transmission rate. A computer program according to claim 11 or 12, comprising:
The transmission power control unit is configured to perform mobile communication via a mobile communication service by another device that performs transmission using the first wireless communication method with another computer that performs transmission using the first wireless communication method. When the communication is relayed to the network, the maximum transmission rate of the mobile communication provided by the mobile communication service is calculated as the required transmission rate, and the required transmission rate is equal to or higher than the predetermined transmission rate. A computer program, wherein a minimum transmission rate is selected as the target transmission rate. A computer program according to claim 15, comprising:
The computer includes a current position calculation unit for calculating a current position,
The transmission power control unit calculates a maximum transmission rate of mobile communication provided by the mobile communication service as the required transmission rate in an area to which the current location calculated by the current location calculation unit belongs. A computer program according to claim 11 or 12, comprising:
The transmission power control unit sets the bit rate of the audio data or video data when the communication using the transmission of the first wireless communication method is to transmit or receive audio data or video data to be reproduced in real time. A computer program which is calculated as a required transmission rate and selects a minimum transmission rate equal to or higher than the required transmission rate among the plurality of predefined transmission rates as the target transmission rate. A computer program according to claim 11, 12, 13, 14, 15, 16, or 17,
The computer program according to claim 1, wherein the first wireless communication system is a wireless LAN wireless communication system defined by the IEEE802.11b or IEEE802.11g standard using the 2.4 MHz band for transmission. A computer program according to claim 18, comprising:
The computer program according to claim 2, wherein the second wireless communication system is a wireless communication system defined by the Bluetooth standard. A computer program according to claim 11, 12, 13, 14, 15, 16, 17, 18 or 19,
A computer program characterized in that the computer is installed in an automobile.