WO2016013291A1

WO2016013291A1 - Received power measurement device, radio communication device, radio communication system and received power measurement method

Info

Publication number: WO2016013291A1
Application number: PCT/JP2015/065299
Authority: WO
Inventors: 昌平飯島
Original assignee: 三菱電機株式会社
Priority date: 2014-07-24
Filing date: 2015-05-27
Publication date: 2016-01-28
Also published as: JP2017163174A

Abstract

This received power measurement device is provided with: a received power measurement request data generation unit (11) which generates request data for requesting a radio communication device (2) to transmit a response signal used for measuring received power, and stores timing information indicating timing at which the response signal is transmitted in the request data; a header addition unit (16) which adds a destination identifier indicating broadcast communication as a destination to the request data in which the timing information is stored; and a radio signal processing unit (13) which transmits, as a radio signal, the request data to which the destination identifier is added, and measures the received power on the basis of the response signal received from the radio communication device (2).

Description

Received power measuring device, wireless communication device, wireless communication system, and received power measuring method

The present invention relates to a received power measuring device, a wireless communication device, a wireless communication system, and a received power measuring method.

Wireless M2M (Machine to Machine) systems (metering systems and remote management systems) that are expected to expand in the future will use wireless communication systems such as IEEE (Institute of Electrical and Electronic Engineers) 802.15.4. The use of the existing multi-hop wireless mesh network is expected. In a multi-hop wireless mesh network, even if there is a wireless device that cannot communicate directly, communication is possible via the relay device by installing the relay device. Therefore, a means for confirming the place where the repeater is to be installed is important.

Confirmation of the installation location of the repeater is possible, for example, by verifying the radio wave coverage of a plurality of wireless devices. Since the radio wave reach of the radio varies depending on the physical environment around the radio, the radio is actually installed, the strength of the radio wave transmitted from the radio (radio wave intensity) is measured in the surrounding area, and the radio wave reach An on-site survey to confirm this is an effective means of radio wave coverage. However, a method for efficiently measuring the radio field intensity of a plurality of wireless devices constituting a multi-hop wireless mesh network has not been established.

There are two methods for measuring radio field strength: a passive type that receives data transmitted by the target radio and measures the radio field intensity, and an active type that communicates with the target radio and measures the radio field intensity when receiving data. There is. The active type includes a method for requesting data transmission for measurement by unicast and a method for requesting data transmission for measurement by broadcast.

In the passive measurement method, there is a problem that measurement is not possible unless the measurement target wireless device transmits data frequently. In addition, in the passive measurement method, in the case of a system using CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) as the access control method, if the measurement target radio is in a hidden terminal state, multiple radios are simultaneously connected. There is a problem in that measurement data may be transmitted and measurement data interfere with each other and cannot be measured.

In the active and unicast measurement method that requires transmission of measurement data to the measurement target radio, there is a problem that the identification number of the measurement target radio must be known. In addition, this measurement method has a problem that it takes time when there are many wireless devices to be measured.

In a measurement method that requires transmission of measurement data to a measurement target radio by active and broadcast, in a system that uses CSMA / CA as an access control method, multiple radios are measured when the measurement target radio is in a hidden terminal state. There is a problem that measurement data from the machine may interfere with each other and cannot be measured.

Patent Document 1 describes that the transmission timing of a response to broadcast data is changed in order to solve the problem of a measurement method that requests transmission of measurement data to a radio device to be measured by an active type and broadcast. is there. However, Patent Document 1 does not describe a specific transmission timing changing method.

JP 2012-026118 A

However, according to the above-described conventional technique, in the case of a system using CSMA / CA when measuring the radio field intensity for checking the radio wave reachable range, there is a possibility that measurement data may interfere with each other and cannot be measured. there were. Japanese Patent Application Laid-Open No. 2004-228561 has a description of changing the transmission timing of a response to broadcast data in a measurement method that requests transmission of measurement data from a wireless device to be measured by active and broadcast. The transmission timing is only shifted in one measurement object. For this reason, if the transmission timing is simply shifted by a fixed time, the transmission timing is determined for each measurement target terminal. When the transmission timing is notified by broadcast, the transmission timing of all measurement target terminals is transmitted to all terminals. Will be sent. For this reason, radio resources for notifying the transmission timing and time for transmission / reception are wasted.

The present invention has been made in view of the above, and a reception power measurement device capable of efficiently measuring reception power based on measurement data transmitted from a plurality of wireless devices while avoiding interference of measurement data, An object of the present invention is to provide a wireless communication device, a wireless communication system, and a received power measurement method.

In order to solve the above-described problems and achieve the object, the present invention generates request data for requesting a wireless communication device, which is a measurement target of reception power, to transmit a response signal used for measurement of reception power. A first processing unit that stores timing information indicating a timing at which the response signal is transmitted in the request data, and a destination identifier indicating that the request data in which the timing information is stored is broadcast communication as a destination A second processing unit that assigns the request data, a radio signal processing unit that transmits the request data to which the destination identifier is assigned as a radio signal, and a received power based on the response signal received from the radio communication device And a third processing unit.

The reception power measuring apparatus according to the present invention has an effect that the reception power based on the measurement data transmitted from a plurality of wireless devices can be efficiently measured while avoiding interference of the measurement data.

FIG. 1 is a diagram illustrating a configuration example of a wireless communication system according to the first embodiment. FIG. 2 is a diagram illustrating a configuration example of the received power measuring device and the wireless communication device to be measured according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of the control circuit according to the first embodiment. FIG. 4 is a flowchart illustrating an example of a reception power measurement process procedure in the reception power measurement apparatus according to the first embodiment. FIG. 5 is a sequence diagram illustrating an example of a received power measurement operation according to the first embodiment. FIG. 6 is a diagram illustrating a configuration example of the received power measuring apparatus according to the second embodiment. FIG. 7 is a flowchart illustrating an example of a procedure for determining a random number width in the received power measurement request data generation unit according to the second embodiment.

Hereinafter, embodiments of a received power measuring device, a wireless communication device, a wireless communication system, and a received power measuring method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of a first embodiment of a wireless communication system according to the present invention. As shown in FIG. 1, the wireless communication system according to the present embodiment includes a received power measuring device 1 and wireless communication devices 2-1 and 2-2 that are reception power measurement targets. The reception power measuring device 1 may be set inside a wireless communication device having a wireless communication function, or may be configured by a combination of a wireless device and an external device. The received power measuring device 1 obtains the received power of each of the wireless communication devices 2-1 and 2-2 based on the signals received from the wireless communication devices 2-1 and 2-2. In FIG. 1, the number of wireless communication devices whose reception power is to be measured is two for simplification of the drawing, but the number of wireless communication devices whose reception power is to be measured is not limited to two. It may be.

FIG. 2 is a diagram illustrating a configuration example of the received power measuring device 1 and the measurement target wireless communication device 2 according to the present embodiment. The wireless communication apparatuses 2-1 and 2-2 have the same configuration, and in FIG. 2, the wireless communication apparatuses 2-1 and 2-2 are illustrated as the wireless communication apparatus 2 without being distinguished from each other.

As shown in FIG. 2, the received power measurement device 1 of this embodiment includes a received power measurement request data generation unit 11, a radio access control unit 12, a radio signal processing unit 13, a received power information collection unit 14, and a radio antenna. 15. The wireless access control unit 12 includes a header adding unit 16 and a transmission source identification unit 17. The wireless signal processing unit 13 includes a reception power measurement unit 18 and a transmission / reception processing unit 30 which are measurement units. Here, an example in which the wireless signal processing unit 13 includes the reception power measurement unit 18 has been described, but the reception power measurement unit 18 may be provided separately from the wireless signal processing unit 13.

The transmission / reception processing unit 30 is an electronic circuit including an analog / digital converter that converts a radio signal received by the radio antenna 15 into a digital signal, a digital / analog converter that converts a digital signal to be transmitted into an analog signal, and the like. The transmission / reception processing unit 30 may include an encoder that performs encoding and a decoder that performs decoding. The transmission / reception processing unit 30 may include a modem that performs modulation and demodulation processing. The reception power measurement unit 18 provided inside the radio signal processing unit 13 or outside the radio signal processing unit is an electronic circuit that measures the power of the radio signal received by the radio antenna 15.

The reception power measurement request data generation unit 11 generates request data for requesting the wireless communication device 2 that is a measurement target of reception power to transmit a response signal used for reception power measurement, and transmits the response signal. It is the 1st processing part which stores the timing information which shows the timing to perform in request data. The header assigning unit 16 is a second processing unit that assigns a destination identifier indicating that the request data in which timing information is stored is broadcast communication as a destination. The transmission / reception processing unit 30 is a third processing unit that transmits the request data to which the destination identifier is assigned as a wireless signal via the wireless antenna 15 and receives the wireless signal via the wireless antenna 15.

The reception power measurement request data generation unit 11, the radio access control unit 12, and the reception power information collection unit 14 are each realized by a processing circuit. That is, the received power measuring apparatus 1 includes a processing circuit that generates received power measurement request data, a processing circuit that performs radio access control, and a processing circuit that collects received power information. The processing circuit that generates the reception power measurement request data, the processing circuit that performs radio access control, and the processing circuit that collects reception power information may be realized as one processing circuit, or the reception power measurement request data Two of the generation unit 11, the radio access control unit 12, and the reception power information collection unit 14 may be realized as one processing circuit. In addition, the header adding unit 16 and the transmission source identification unit 17 of the wireless access control unit 12 may be realized as separate processing circuits. Even if these processing circuits are dedicated hardware, a CPU (Central Processing Unit, a central processing unit, a processing unit, a processing unit, a microprocessor, a microcomputer, a processor, which executes a memory and a program stored in the memory, A control circuit provided with a DSP (Digital Signal Processor) may also be used. Here, the memory is, for example, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory, etc.) Volatile semiconductor memories, magnetic disks, flexible disks, optical disks, compact disks, mini disks, DVDs (Digital Versatile Disks), and the like are applicable.

When the processing circuit that implements the reception power measurement request data generation unit 11, the wireless access control unit 12, and the reception power information collection unit 14 is dedicated hardware, the processing circuit is, for example, a single circuit, a composite circuit, or a program An integrated processor, a processor programmed in parallel, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof is applicable.

When the processing circuit that implements the received power measurement request data generation unit 11, the radio access control unit 12, and the received power information collection unit 14 is a control circuit including a CPU, the control circuit is, for example, a control circuit configured as shown in FIG. 200. As shown in FIG. 3, the control circuit 200 is an input unit 201 that is a receiving unit that receives data input from the outside, a processor 202 that is a CPU, a memory 203, and a transmission unit that transmits data to the outside. And an output unit 204. The input unit 201 is an interface circuit that receives data input from the outside of the control circuit 200 and applies the data to the processor 202, and the output unit 204 is an interface that transmits data from the processor 202 or the memory 203 to the outside of the control circuit 200. Circuit. When the processing circuit is realized by the control circuit 200 shown in FIG. 3, the processor 202 is realized by reading and executing a program stored in the memory 203 and corresponding to each processing of the processing circuit. The memory 203 is also used as a temporary memory in each process executed by the processor 202.

A part of the functions of the processing circuit that implements the reception power measurement request data generation unit 11, the radio access control unit 12, and the reception power information collection unit 14 is realized by dedicated hardware, and part of the processing circuit is software or firmware. It may be realized.

In addition, when the reception power measuring device is configured by a combination of a wireless device and an external device, for example, the wireless access control unit 12, the wireless signal processing unit 13, and the antenna 15 are realized by the wireless device, and the received power measurement request The data generation unit 11 and the reception power information collection unit 14 are realized by an external device. In this case, the control circuit 200 that implements the received power measurement request data generation unit 11 and the received power information collection unit 14 is an external device such as a personal computer. The separation between the wireless device and the external device is not limited to this example. For example, the wireless signal processing unit 13 and the antenna 15 are realized by the wireless device, and the received power measurement request data generation unit 11 and the wireless access control unit 12 are provided. The received power information collection unit 14 may be realized by an external device.

The wireless communication device 2 that is a measurement target includes a wireless signal processing unit 21 (measurement target side wireless signal processing unit), a wireless access control unit 22, and a wireless antenna 23. The radio access control unit 22 includes a header analysis unit 24, a request data analysis unit 25, a received power measurement response data generation unit 26, and a transmission timing control unit 27.

The reception power measurement response data generation unit 26 is a generation unit that generates response data corresponding to the received request data when the request data is received from the reception power measurement device. The transmission timing control unit 27 is a control unit that determines transmission timing based on timing information stored in the received request data. The radio signal processing unit 21 sends a response signal, which is a radio signal storing the response data generated by the response power measurement response data generation unit 26 at the transmission timing instructed by the transmission timing control unit 27, to the reception power measurement device. A processing unit for transmission. A wireless signal in which response data is stored is called a response signal.

The radio signal processing unit 21 is an electronic circuit including an analog / digital converter that converts a radio signal received by the radio antenna 23 into a digital signal, a digital / analog converter that converts a digital signal to be transmitted into an analog signal, and the like.

The header analysis unit 24, request data analysis unit 25, reception power measurement response data generation unit 26, and transmission timing control unit 27 of the wireless access control unit 22 are realized by a processing circuit. That is, the wireless communication device 2 includes a processing circuit that analyzes the header, analyzes the request data, and generates response data for reception power measurement. The processing circuit may be dedicated hardware or a control circuit including a memory and a CPU that executes a program stored in the memory.

When the processing circuit that implements the header analysis unit 24, the request data analysis unit 25, the received power measurement response data generation unit 26, and the transmission timing control unit 27 is dedicated hardware, the processing circuit is, for example, a single circuit, A composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof is applicable.

When the processing circuit that implements the header analysis unit 24, the request data analysis unit 25, the reception power measurement response data generation unit 26, and the transmission timing control unit 27 is a control circuit including a CPU, the control circuit is, for example, shown in FIG. This is a control circuit 200 having a configuration. When the processing circuit for realizing the header analysis unit 24, the request data analysis unit 25, the reception power measurement response data generation unit 26, and the transmission timing control unit 27 is realized by the control circuit 200 shown in FIG. This is realized by reading out and executing the program corresponding to each processing of the processing circuit stored in the memory.

Some of the functions of the processing circuit that implements the header analysis unit 24, the request data analysis unit 25, the received power measurement response data generation unit 26, and the transmission timing control unit 27 are realized by dedicated hardware, and a part thereof It may be realized by software or firmware.

In the wireless communication system of this embodiment, communication using CSMA / CA is performed. When CSMA / CA is used, the wireless communication device checks whether there is a wireless communication device performing communication (carrier sense), and determines that no other wireless communication device is performing communication. Data is transmitted after waiting for a waiting time called a back-off time determined based on.

Next, the operation of the present embodiment will be described. FIG. 4 is a flowchart showing an example of a received power measurement processing procedure in the received power measuring apparatus 1 of the present embodiment. In the reception power measuring apparatus 1, the reception power measurement request data generation unit 11 determines timing information for determining the transmission timing of the response signal in the wireless communication apparatuses 2-1 and 2-2 to be measured (step S1). ). The timing information may be determined in advance by the received power measurement request data generation unit 11, or the received power measurement request data generation unit 11 may acquire timing information input from the outside. It may be. In the present embodiment, as timing information, the measurement target wireless communication apparatuses 2-1 and 2-2 use a random number width and a time interval, which are parameters for calculating a backoff time in CSMA / CA. To do. The width of the random number indicates the number of types of values that the random number can take when generating the random number. When generating a random number with an integer, the width of the random number indicates the range that the random number can take. The back-off time is a time obtained by multiplying the random number generated based on the width of the random number and the time interval. The random number width is set to a value at which the probability that interference cannot be avoided is equal to or less than the desired probability, depending on the number of wireless communication devices 2 to be measured. Specifically, when interference cannot be avoided, that is, the probability of selecting the same random number is calculated from the number of wireless communication devices to be measured. The wider the range of random numbers, the lower the probability that the same random number will be generated, and the higher the number of wireless communication devices to be measured, the higher the probability that the same random number will be generated. The random number width is determined such that the larger the number of devices, the larger the random number width, and the lower the desired probability, the wider the random number width. For example, when generating a random number as an integer, assuming that n is the number of wireless communication devices to be measured and the width of the random number is W _r , the probability that two wireless communication devices generate the same random number is _n C ₂ × (1 / W _r ) × 100%. Therefore, if the desired probability is P _r %, W _r is determined so that _n C ₂ × (1 / W _r ) × 100 ≦ P _r , that is, W _r ≧ _n C ₂ × 100 / P _r . C represents a combination. For example, if the W _r and that determined as _{_{_{W r = n C 2 × 100}}} / P r, if you want to set the probability of random numbers to be measured of the wireless communication apparatus does not select the same random number in the two 10% or less, The width of the random number is 10. Note that the method of determining the random number width is not limited to this method, and any method may be used as long as the number of wireless communication devices increases, the random number width increases, and the lower the desired probability, the wider the random number width. The time interval is set to a time exceeding the transmission time of the response signal (the time required from the start of transmission to the completion of transmission when the wireless communication apparatus transmits the response signal). The transmission time of the response signal is obtained in advance by measurement or the like, for example. As described above, the width of the random number and the time interval are calculated in advance and set in the received power measurement request data generation unit 11. In addition, you may comprise so that the width | variety of a random number and a time interval can be changed. Alternatively, the above-described desired probability and the number of measurement target wireless communication devices can be input from the outside, and the received power measurement request data generation unit 11 can input the input desired probability and the measurement target wireless communication. The random number width may be determined based on the number of devices.

The reception power measurement request data generation unit 11 generates reception power measurement request data (hereinafter, referred to as request data as appropriate) in order to request the measurement target wireless communication apparatus to transmit a response signal used for reception power measurement. Then, the data is transmitted through the wireless access control unit 12, the transmission / reception processing unit 30, and the wireless antenna 15 (step S2). The generated request data stores information for requesting measurement and a random number width and a time interval that are parameters for calculating the back-off time, that is, timing information. In step S2, specifically, the reception power measurement request data generation unit 11 generates reception power measurement request data to request transmission of a response signal, and outputs it to the header assignment unit 16 of the radio access control unit 12. Then, the header adding unit 16 includes, in the generated request data, an identifier indicating request data, an identifier indicating broadcast (broadcast communication) as a destination, a transmission source identifier, that is, the received power measuring device 1. Are assigned as headers. Further, information other than these may be included in the header. In addition, since the response data should just be transmitted as a radio signal for a measurement, the content of response data may be what. Thereafter, the transmission / reception processing unit 30 transmits the request data (response request signal) to which the header is added as a radio signal from the radio antenna 15.

In the wireless communication devices 2-1 and 2-2, the received wireless signal is transferred to the wireless access control unit 22 through the wireless antenna 23 and the wireless signal processing unit 21. When the header analysis unit 24 of the radio access control unit 22 analyzes the header of the received radio signal and confirms that it is request data, it passes the request data to the request data analysis unit 25. The request data analysis unit 25 notifies the reception power measurement response data generation unit 26 so as to generate reception power measurement response data (hereinafter referred to as response data as appropriate) corresponding to the received request data. The transmission timing control unit 27 is notified of the stored timing information. The received power measurement response data generation unit 26 generates response data, adds a header of a destination identifier or a transmission source identifier to the response data, and passes the response data to the transmission timing control unit 27. The transmission control timing control unit 27 calculates the backoff time based on the notified timing information, and controls the transmission timing of the radio signal storing the response data, that is, the response signal, based on the calculated backoff time. Specifically, the transmission control timing control unit 27 instructs the wireless signal processing unit 21 on the transmission timing. Based on an instruction from the transmission control timing control unit 27, the wireless signal processing unit 21 transmits the response data with the header added thereto as a wireless signal to the reception power measuring device 1 via the wireless antenna 23.

Returning to the description of FIG. 4, when the received power measuring apparatus 1 receives a radio signal in which response data is stored, that is, a response signal, the received power measuring unit 18 of the radio signal processing unit 13 receives a radio signal (response signal). Is measured (step S3). The received power measurement unit 18 notifies the transmission source identification unit 17 of the measurement result and response data.

The transmission source identification unit 17 extracts the identifier of the transmission source wireless communication device (measurement target wireless communication device) from the response data, and notifies the reception power information collection unit 14 together with the measurement result (reception power value). The received power information collection unit 14 associates and stores the identifier of the wireless communication device to be measured and the received power value (step S4). When the reception power information collection unit 14 is realized by hardware, the identifier and reception power value of the wireless communication device to be measured are stored in an internal memory, and the reception power information collection unit 14 is realized by software. Stored in the memory 203 of the control circuit 200.

The received power measuring apparatus 1 performs step S3 and step S4 each time response data is received. Through the above processing, the received power can be measured for each wireless communication device to be measured.

FIG. 5 is a sequence diagram showing an example of the received power measurement operation of the present embodiment. As described in step S2 above, the received power measuring apparatus 1 transmits the request data by broadcasting (step S11). When receiving the request data, the wireless communication device 2-1 calculates the backoff time # 1 based on the timing information stored in the received request data, and determines that no other communication is performed by carrier sense. Back-off time # 1 is waited (step S12), and then response data is transmitted (step S13). When receiving the request data, the wireless communication device 2-2 calculates the backoff time # 2 based on the timing information stored in the received request data, and determines that no other communication is performed by carrier sense. Back-off time # 2 is waited (step S14), and then response data is transmitted (step S15).

Note that a wireless communication device having both the function as the reception power measuring device 1 and the function as the measurement target wireless communication device 2 is configured, and each wireless communication device measures the reception power and response data for the measurement. It may be possible to carry out both of the transmission of.

As described above, the reception power measurement device 1 designates timing information when the wireless communication device transmits response data, so that reception power is efficiently measured while reducing interference between the plurality of wireless communication devices. The effect that it can be obtained.

Embodiment 2. FIG.
FIG. 6 is a diagram showing a configuration example of the second embodiment of the received power measuring apparatus 1a according to the present invention. The radio communication system of the present embodiment is the same as that of the first embodiment except that the received power measuring apparatus 1a is provided instead of the received power measuring apparatus 1 of the present embodiment. As shown in FIG. 6, the received power measurement apparatus 1a according to the present embodiment is configured to measure the received power according to the first embodiment except that the wireless access control unit 12a is provided instead of the wireless access control unit 12 according to the first embodiment. It is the same as the device 1. The radio access control unit 12a has a configuration in which an error detection unit 19 is added to the radio access control unit 12 of the first embodiment. The wireless communication device 2 to be measured is the same as that in the first embodiment. Constituent elements having the same functions as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted, and different parts from those in the first embodiment are described.

The error detection unit 19 may be a dedicated circuit or a control circuit including a memory and a CPU that executes a program stored in the memory. Further, the error detection unit 19 may be realized as one processing circuit together with other components.

When the processing circuit that implements the error detection unit 19 is dedicated hardware, the processing circuit is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. Applicable.

When the processing circuit for realizing the error detection unit 19 is a control circuit including a CPU, the control circuit is realized as a control circuit 200 having the configuration shown in FIG. When the processing circuit for realizing the error detection unit 19 is realized by the control circuit 200 shown in FIG. 3, the processor 202 reads and executes the program stored in the memory 203 and corresponding to the processing of the error detection unit 19. Realized.

In Embodiment 1, the width of the random number that is the timing information is determined according to the number of wireless communication devices to be measured. However, the number of wireless communication devices that can receive the request data may change for each measurement point. For this reason, if the width of the random number is determined with the wireless communication device to be measured fixed, the measurement efficiency may be reduced.

Therefore, in the present embodiment, the error detection unit 19 performs error detection based on the received data, calculates an index indicating the frequency of errors (for example, the number of errors within a certain time), and measures received power. The request data generation unit 11 is notified. In general, when interference is caused by a plurality of wireless communication devices 2, errors in received data increase. Therefore, when the index notified from the error detection unit 19 is greater than or equal to the first threshold (when the error within a certain time is greater than or equal to the first threshold), the received power measurement request data generation unit 11 If the index indicating the frequency of errors is a value indicating that there are few errors, for example, if the error within a certain time is equal to or smaller than the second threshold, the timing method is set so as to reduce the width of the random number. decide. Note that the second threshold ≦ the first threshold. Then, the timing information calculated in this way is notified to the wireless communication device 2, thereby suppressing the occurrence of interference. The operations of the present embodiment other than those described above are the same as those of the first embodiment.

As an index indicating the frequency of errors calculated by the error detection unit 19, for example, the number of packets determined to contain errors among the response signal packets received within a certain time can be used. In this case, the error detection unit 19 uses information for error detection such as a checksum, parity, CRC (Cyclic Redundancy Check) stored in the response signal to determine whether or not the packet includes an error for each packet. Is determined, and the number of response signals determined to contain errors in packets received within a predetermined time is obtained. Alternatively, when the response data stored in the received response signal is error correction encoded, it is possible to determine whether or not there is an error in error correction decoding. Similarly, the number of response signals determined to contain errors in the response signal packets received within a predetermined time may be obtained. Alternatively, when the sequence number is included in the received response signal packet, the error detection unit 19 obtains the response signal packet that could not be normally received based on the sequence number, and determines the error frequency. As an index to indicate, the number of response signal packets that could not be normally received within a certain period of time may be used.

FIG. 7 is a flowchart illustrating an example of a random number width determination processing procedure in the received power measurement request data generation unit 11 according to the present embodiment. The received power measurement request data generation unit 11 determines the random number width by the process described in the first embodiment (step S21). Next, the received power measurement request data generation unit 11 determines, for example, whether or not the index notified from the error detection unit 19 is equal to or greater than a first threshold (step S22). If it is determined that the index is greater than or equal to the first threshold (Yes at Step S22), the range of random numbers is expanded (Step S23), and the process returns to Step S22. In step S23, specifically, the received power measurement request data generation unit 11 sets, for example, a value obtained by adding a constant value to the random number width as a new random number width, or a constant greater than 1 in the random number width. A value obtained by multiplying the values is set as a new random number width.

If it is determined in step S22 that the index is less than the first threshold (No in step S22), the process proceeds to step S24. In step S24, the received power measurement request data generation unit 11 determines whether the index is less than or equal to the second threshold (step S24), and determines that the index is less than or equal to the second threshold (step S24). (S24 Yes), the width of the random number is reduced, that is, reduced (step S25), and the process returns to step S22. In step S25, specifically, the received power measurement request data generation unit 11 sets, for example, a value obtained by subtracting a constant value from the random number width as a new random number width, or the random number width is constant larger than 1. The value divided by the value is used as the new random number width. If it is determined in step S24 that the index is greater than the second threshold (No in step S24), the process returns to step S22. In addition, an upper limit may be provided for the random number width, and the received power measurement request data generation unit 11 may not increase the random number width when the expanded random number width exceeds the upper limit in step S23. Similarly, the lower limit of the random number width is set, and the received power measurement request data generation unit 11 does not reduce the random number width when the reduced random number width is lower than the lower limit in step S25. Also good.

In the above example, the index indicating the frequency of errors has been described as having a positive correlation with the number of errors. However, as an index indicating the frequency of errors, for example, the intensity of errors such as the strength of received power is negative. A correlated index may be used. In this case, in the determination in step S22 described above, it is determined whether or not the index is less than or equal to the first threshold value. In the determination in step S24, it is determined whether or not the index is greater than or equal to the second threshold value. In this case, the second threshold ≧ the first threshold.

As described above, in the present embodiment, the error detection unit 19 detects an error in the received data, and the received power measurement request data generation unit 11 determines that the random number is a random number when the number of errors within a certain time is equal to or greater than a certain number. The width of is increased, and when there are few errors, the random number is reduced. For this reason, the received power measurement can be performed more efficiently than in the first embodiment.

Embodiment 3 FIG.
Next, a received power measuring apparatus according to the third embodiment of the present invention will be described. The radio communication system of the present embodiment is the same as that of the first embodiment. Hereinafter, a different part from Embodiment 1 is demonstrated.

In Embodiments 1 and 2, since interference reduction is realized stochastically by changing the width of the random number, reliable interference avoidance cannot be realized. In the present embodiment, the received power measurement request data generation unit 11 transmits, as timing information, a parameter for determining the transmission timing based on the identifier of the wireless communication device 2. For example, when the identifier of the wireless communication device 2 is x, a function f (x) for determining the back-off time in the wireless communication device 2 is determined, and a parameter used for f (x) (for example, a secondary of x In the case of a function, second order and first order coefficients and constants) are transmitted as timing information. Specifically, for example, f (x) = a × x ² + b × x + c is determined, and the received power measurement request data generation unit 11 transmits a, b, and c to the wireless communication device 2. The transmission timing control unit 27 of the wireless communication device 2 holds the function f (x) in an internal memory. The function f (x) is stored in a memory in the processing circuit when the transmission timing control unit 27 is configured as a processing circuit together with other components. Alternatively, the transmission timing control unit 27 may include a dedicated electronic circuit that outputs the function f (x) when the coefficients a, b, and c are input. The transmission timing control unit 27 of the wireless communication apparatus 2 calculates the back-off time using the function f (x), the received parameter, and its own identifier. Note that the received power measurement device according to the present embodiment calculates a different backoff time for each wireless communication device 2 based on the identifier of the wireless communication device 2, and determines the backoff time for each wireless communication device 2 for each wireless communication device. You may transmit to the apparatus 2 as timing information.

Alternatively, the wireless communication device 2 may generate a random number as follows. The reception power measurement request data generation unit 11 transmits, as timing information, parameters for generating a random number that is a source of generation of the backoff time, as in the first embodiment. The wireless communication device 2 generates a random number based on the timing information. At this time, the wireless communication device 2 generates a random number according to its own identifier. For example, a radio identifier is used as a seed for determining a random number sequence, and a seed is set to generate a random number. Then, the back-off time is determined based on this random number. The operations of the present embodiment other than those described above are the same as those of the first embodiment.

As described above, in this embodiment, the back-off time is determined based on the identifier of the wireless communication device 2 so that the back-off time is different for each wireless communication device 2 to be measured. Since the wireless identifier is unique to each wireless communication device 2, it is possible to avoid interference. By controlling in this way, the received power can be measured while reliably avoiding interference, and the efficiency can be improved.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1, 1a received power measurement device, 2, 2-1, 2-2 wireless communication device, 11 received power measurement request data generation unit, 12, 12a, 22 wireless access control unit, 13, 21 wireless signal processing unit, 14 Received power information collection unit, 15, 23 wireless antenna, 16 header assignment unit, 17 transmission source identification unit, 18 received power measurement unit, 19 error detection unit, 24 header analysis unit, 25 request data analysis unit, 26 for received power measurement Response data generation unit, 27 transmission timing control unit, 30 transmission / reception processing unit.

Claims

Request data for requesting transmission of a response signal used for reception power measurement to a wireless communication apparatus that is a reception power measurement target is generated, and timing information indicating the timing of transmitting the response signal is included in the request data. A first processing unit for storing;
A second processing unit that assigns a destination identifier indicating that the request data in which the timing information is stored is broadcast communication as a destination;
A third processing unit that transmits the request data to which the destination identifier is assigned as a radio signal;
A measurement unit that measures received power based on the response signal received from the wireless communication device;
A received power measuring apparatus comprising:
The received power measuring apparatus according to claim 1, wherein the timing information is a parameter for determining a waiting time until the wireless communication apparatus transmits the response signal.
The waiting time is a value obtained by multiplying a random number and a time interval,
The received power measuring apparatus according to claim 2, wherein the parameters are a random number width used when generating the random number and the time interval.
An error detector for detecting an error in the response signal;
Further comprising
The received power measuring apparatus according to claim 1, 2, or 3, wherein the timing information is changed based on an error detection result by the error detection unit.
The received power measuring device according to any one of claims 1 to 4, wherein the timing information is generated based on an identifier of the wireless communication device.
The received power measuring device according to claim 1,
A wireless communication apparatus comprising:
Response data corresponding to the received request data is received when request data for requesting transmission of the response signal is received from the received power measurement device and timing information indicating the timing of transmitting a response signal used for measurement of received power is stored. A generating unit for generating
A control unit that determines transmission timing based on the timing information stored in the received request data;
A processing unit that transmits the response signal, which is a radio signal storing the response data generated by the generation unit at the transmission timing instructed by the transmission timing control unit, to the reception power measuring device;
A wireless communication apparatus comprising:
The received power measuring device according to any one of claims 1 to 5,
A wireless communication system comprising: the wireless communication device according to claim 7.
A first step of generating request data for requesting transmission of a response signal used for reception power measurement to a wireless communication device that is a measurement target of reception power;
A second step of storing timing information indicating the timing of transmitting the response signal in the request data;
A third step of assigning a destination identifier indicating that the request data in which the timing information is stored is broadcast as a destination;
A fourth step of transmitting the request data provided with the destination identifier as a radio signal;
A fifth step of measuring received power based on the response signal received from the wireless communication device;
A received power measuring method.