JP6695821B2 - Measuring device and measuring method - Google Patents

Description

  The present invention relates to a measuring device and a measuring method for measuring transmission / reception characteristics of a wireless LAN communication device.

  There is a wireless LAN (Wireless LAN) as one of communication methods using a wireless line. One of the standards for this wireless LAN is IEEE 802.11. In the case of a system complying with the IEEE 802.11 standard, a master unit called an AP (Access Point, also called an access point) and a slave unit called an STA (Station, also called a station) connected to the AP communicate with each other. There is something to take. As an example of this communication, when there is an obstacle between the STAs, the communication between the STAs is not established, and another STA tries to access the same AP at the same time by using the same channel (bandwidth). I can't recognize that. In such a case, it is called "hidden terminal problem".

  In the environment where the hidden terminal problem occurs, when a plurality of STAs simultaneously access the same AP using the same channel, the signals transmitted by the respective STAs may cause channel collision. As a method of avoiding such a situation, CSMA / CA (Carrier Sense Multiple Access with Collison Avoidance) is used in the IEEE 802.11 standard. CSMA / CA has several procedures, for example, the procedure using RTS / CTS as shown below.

The AP monitors the channel usage status with the 20 MHz bandwidth as the minimum bandwidth, and notifies the STA of the channels in which communication is possible. Upon receiving this notification, the STA exchanges the following channel use request signal RTS and use permission signal CTS with the AP to determine the channel for communication.
(1) STA to AP: A request for a channel to be used is notified by transmitting a control packet RTS (Request to Send) on the channel to be used.
(2) AP to STA: A response indicating availability is notified by transmitting a control packet CTS (Clear to Send) on an available channel.

  In addition, the IEEE 802.11 standard is gradually added with many technologies as functions are added and advanced. For example, from IEEE 802.11n, a function of supporting a plurality of communication bandwidths, which is a technique for increasing the communication speed of a wireless LAN, has been added.

  By supporting multiple bandwidths, it is possible to increase the amount of data to be transmitted and received at one time, and to increase the communication speed. The supported bandwidths are 20 MHz and 40 MHz in IEEE 802.11n, but they can be made variable according to the channel usage status such as 20 MHz, 40 MHz, 80 MHz, and 160 MHz in IEEE 802.11ac.

  In an STA conforming to the IEEE802.11ac standard, when it is desired to use the 80 MHz bandwidth by using four consecutive channels, the channel that is desired to be used for the AP that has transmitted the notification of the communicable channel is the continuous channel for the entire 80 MHz. The control packet RTS having the 20 MHz bandwidth is transmitted.

  When the AP and the STA have a one-to-one relationship, the AP sends a control packet CTS that permits data communication in the 80 MHz bandwidth to the STA. However, when a plurality of STAs access one AP, that is, when the APs and the STAs have a one-to-many relationship, channel collision may occur using the hidden terminal problem as an example. For example, if the DUT is STA1, even if STA1 requests the AP to use the 80 MHz bandwidth of channel numbers 52, 56, 60, 64, at the same time, STA2 requests the 80 MHz bandwidth requested by STA1. Channel collisions may occur that require the use of channels in overlapping bands (40 MHz bandwidth of channel numbers 60 and 64).

  When the channel use requests from STA1 and STA2 thus collide, the AP limits the use of the 40 MHz bandwidth of the overlapping channel numbers 60 and 64 by the CSMA / CA described above, and the channel number 52 , 56 by transmitting the control packet CTS only for the 40 MHz bandwidth, the AP permits STA1 to use the 40 MHz bandwidth of the channel numbers 52, 56. Upon receiving the control packet CTS, the STA1 recognizes that the use of the 40 MHz bandwidth of the channel numbers 52 and 56 is permitted, and transmits the data packet to the AP using the 40 MHz bandwidth of the channel numbers 52 and 56.

  In Patent Document 1, in a channel permitted to be used by CSMA / CA, the signal quality of the channel at the time of transmitting a data packet is determined, and when it is determined that the signal quality of the channel is poor, band limitation and rate limitation are applied to the channel. By imposing it, communication is not cut off.

JP, 2005-12471, A

  In order to use the wireless LAN system comfortably, the operation verification of the STA is very important. For this reason, it is common practice to bring in an STA, which is the object to be measured, in a measurement environment simulating an actual environment to confirm the actual operation of the STA.

  In such a test, there is a demand to measure, for example, a packet error rate or throughput in the channel requested by the STA. However, as described in Patent Document 1, when the AP determines the signal quality of the channel, for example, the usage status of the channel, and performs control to limit the permission of use to the channel requested by the STA, the measurement device For the STA as the DUT, there arises a problem that it is impossible to measure, for example, the packet error rate or the throughput in the requested channel or to test the transmission / reception characteristics of the DUT such as EVM (Error Vector Magnitude). ..

  Usually, it is common to measure the STA that is the DUT by itself in an environment that shields other external waves such as a shield box or shield room, but it is not necessarily an environment where there is no external wave, and When there is a radio wave from another STA that is not the measurement object, for example, in a measurement in an environment including an interference wave, the AP limits the permission of use to the channel requested by the STA that is the measurement object. However, there is a problem that the test cannot be performed on the desired channel.

  The present invention has been made to solve such conventional problems, and an object thereof is to provide a measuring device and a measuring method that enable packet error measurement and throughput measurement in a channel required by a device under test. And

  A measuring device (1) according to claim 1 of the present invention transmits and receives a signal to and from a device under test (100) using a wireless line composed of a plurality of channels, and the transmitting and receiving characteristics of the device under test are measured. A measuring device (1) for measuring a signal, and a receiving unit (11) for receiving a use request signal for each channel using a use request channel transmitted from the DUT when starting transmission / reception of the signal. A signal analysis unit (13) that analyzes the signal quality of each channel based on the received usage request signal of each channel; and a usage request of the usage request signal based on the result of analyzing the signal quality. Processing unit (50) for deciding whether or not to permit use of the selected channel, and a transmission unit for transmitting a use permission signal for each channel using the use request channel determined to be permitted by the processing unit (10), and a function storage unit (60) in which control mode information designating whether or not to permit the use of each channel based on the signal quality of each channel is stored, The processing unit, based on the signal quality for each channel as a result of the analysis of the signal quality and the control mode information stored in the function storage unit, determines whether to permit use for each channel. The signal analysis unit is a measuring apparatus, characterized in that the processing unit measures the transmission / reception characteristics of the device under test using the channel for which the processing unit has determined permission to use the channel.

  With this configuration, the measurement device according to claim 1 of the present invention sets the analysis result of the received signal and the measurement device when determining permission to use the channel requested by the DUT. Based on the control mode information, it is possible to control the use permission, and it is possible to give the use permission to the channel for which the DUT has requested the use according to the intention of the operator of the measuring device. Thus, even in an environment where there is an external wave and an interfering wave, for example, a radio wave arriving from another STA that is not the DUT, it is possible to test the transmission / reception characteristics of the DUT regarding the channel for transmitting / receiving a signal to / from the DUT. It can be performed arbitrarily.

  The measurement apparatus according to claim 2 of the present invention is characterized in that the use request signal for each channel is transmitted on a channel continuously used in a bandwidth supported by the device under test. The measuring device according to 1.

  With this configuration, the measuring apparatus according to the second aspect of the present invention requires the device under test to use even in the control method in which the bandwidth (the number of continuous channels) used changes according to the signal quality of the channel, for example. When permitting the use of the channel, the use permission can be controlled by the control mode information of the measuring device. This allows an arbitrary test to be performed even when the bandwidth used (the number of consecutive channels) changes dynamically.

  In the measuring apparatus according to claim 3 of the present invention, the control mode information is irrespective of the signal quality of the plurality of channels with respect to the use request signal for each of the plurality of channels transmitted from the device under test. 3. The measuring apparatus according to claim 2, further comprising a mode in which use is permitted for all the channels requested to be used.

  With this configuration, the measuring apparatus according to claim 3 of the present invention, for example, in the control method in which the bandwidth (the number of continuous channels) used changes according to the signal quality of the channel, for all the requested channels, It becomes possible to transmit the use permission, and it is possible to perform an arbitrary test without limiting the number of channels used.

  The measuring apparatus according to claim 4 of the present invention is characterized in that the control mode information stored in the function storage section is rewritable. It is the described measuring device.

  With this configuration, the measuring device according to the fourth aspect of the present invention can enable the operator to easily switch the control mode information. This makes it possible to perform an arbitrary test intended by the operator when performing a test using the function of the measuring apparatus of the present embodiment.

  In the measuring apparatus according to claim 5 of the present invention, when the signal analyzing unit measures the signal quality of each of the channels, the received electric field strength and S / N of the signal sent from the DUT are measured. The measuring device according to any one of claims 1 to 4, characterized in that at least is used.

  With this configuration, the measuring apparatus according to the fifth aspect of the present invention can appropriately measure the signal quality. This makes it possible to perform an arbitrary test intended by the operator when performing a test using the function of the measuring apparatus of the present embodiment.

  The measuring method according to claim 6 of the present invention uses a wireless line composed of a plurality of channels to transmit and receive a signal to and from an object to be measured, and to measure transmission and reception characteristics of the object to be measured. That is, when starting the transmission and reception of the signal, receiving the use request signal for each channel using the use request channel transmitted from the DUT, based on the received use request signal for each channel The signal quality of each channel is analyzed, and control mode information designating whether or not to permit the use of each channel based on the signal quality of each channel is stored in a control mode information storage area. Based on the signal quality for each channel of the result of quality analysis and the control mode information stored in the control mode information storage area, it is determined whether or not to permit use for each channel, The measurement method is characterized in that the transmission / reception characteristics of the device under test are measured using a channel for which usage permission has been determined.

  With this configuration, the measurement method according to claim 6 of the present invention controls the channel use permission by the control mode information held by the measurement device when permitting the use of the channel requested by the device under test. It becomes possible to permit the use of the channel requested by the device under test according to the intention of the operator of the measuring apparatus. Thus, even in an environment where there is an external wave and an interfering wave, for example, a radio wave arriving from another STA that is not the DUT, it is possible to test the transmission / reception characteristics of the DUT regarding the channel for transmitting / receiving a signal to / from the DUT. It can be performed arbitrarily.

  The measurement method according to claim 7 of the present invention, wherein the use request signal for each channel is transmitted on a channel continuously used in a bandwidth supported by the device under test. 6 is the measuring method.

  With this configuration, in the measurement method according to the seventh aspect of the present invention, the device under test requires use even in the control method in which the bandwidth used (number of continuous channels) changes according to the signal quality of the channel, for example. When permitting the use of the channel, the use permission can be controlled by the control mode information of the measuring device. This allows an arbitrary test to be performed even when the bandwidth used (the number of consecutive channels) changes dynamically.

  In the measuring method according to claim 8 of the present invention, the control mode information is irrespective of the signal quality of the plurality of channels with respect to the use request signal for each of the plurality of channels transmitted from the DUT. The measurement method according to claim 7, further comprising a mode in which use is permitted for all of the use-requested channels.

  With this configuration, in the measurement method according to claim 8 of the present invention, for example, in the control method in which the bandwidth used (the number of consecutive channels) changes according to the signal quality of the channel, for all the requested channels, It becomes possible to transmit the use permission, and it is possible to perform an arbitrary test without limiting the number of channels used.

  9. The measuring method according to claim 9 of the present invention, wherein the control mode information stored in the control mode information storage area is rewritable. The measurement method described in the item.

  With this configuration, the measuring device according to the ninth aspect of the present invention enables the operator to easily switch the control mode information. This makes it possible to perform an arbitrary test intended by the operator when performing a test using the function of the measuring apparatus of the present embodiment.

  According to a tenth aspect of the present invention, in the analysis of the signal quality of each channel, when measuring the signal quality of each channel, a received electric field strength of the signal sent from the DUT is measured. 10. The measuring method according to claim 6, wherein at least S / N is used.

  With this configuration, the measuring method according to the tenth aspect of the present invention can appropriately measure the signal quality. This makes it possible to perform an arbitrary test intended by the operator when performing a test using the function of the measuring apparatus of the present embodiment.

  The present invention provides a measuring apparatus and a measuring method that can permit use of a channel requested by the device under test 100 regardless of the signal quality of the channel.

FIG. 1 is a block diagram showing the configuration of an embodiment of a measuring apparatus according to the present invention. FIG. 2 is a diagram showing a detailed configuration of the signal analysis unit shown in FIG. FIG. 3 is a diagram showing an example of bit assignment of the mode area stored in the function storage unit. FIG. 4 shows a case where it is determined that no channel collision has occurred in the channel requested by the DUT, as a result of confirmation of the signal quality of the channel in the channel control processing in the embodiment of the measuring apparatus according to the present invention. FIG. 3 is a diagram showing transmission and reception of signals (control packets). FIG. 5 shows a case in which it is determined that a channel collision has occurred in a channel requested by the device under test as a result of confirmation of the signal quality of the channel in the channel control process in one embodiment of the measuring apparatus according to the present invention. FIG. 3 is a diagram showing transmission and reception of signals (control packets). FIG. 6 shows a case in which it is determined in the embodiment of the measuring apparatus according to the present invention that the channel quality is confirmed in the channel control processing, and it is determined that channel collision has occurred in the channel requested by the DUT. FIG. 3 is a diagram showing transmission and reception of signals (control packets). FIG. 7A is an overall processing flow of channel control processing in an embodiment of the measuring apparatus according to the present invention. FIG. 7B is an RTS analysis processing flow in the channel control processing in the embodiment of the measurement apparatus according to the present invention. FIG. 7C is an RTS analysis processing flow in the channel control processing in the embodiment of the measurement apparatus according to the present invention. FIG. 7D is an RTS analysis processing flow in the channel control processing in the embodiment of the measurement apparatus according to the present invention. FIG. 7E is an RTS analysis processing flow in the channel control processing in the embodiment of the measurement apparatus according to the present invention. FIG. 8 is a mode confirmation processing flow for confirming the mode of the channel control processing in the embodiment of the measurement apparatus according to the present invention. FIG. 9 is a diagram showing an example of the permission notification management table and its setting values. FIG. 10 shows a usage permission signal for a control packet RTS which is a usage request signal transmitted by the DUT 100 according to the value of the CTS creation status of the permission notification management table in the embodiment of the measuring apparatus according to the present invention. Is a processing flow for creating a CTS that is FIG. 11 is a diagram showing another example of the bit assignment of the function storage unit. FIG. 12 is another mode confirmation processing flow for confirming the mode of the channel control processing in the embodiment of the measurement apparatus according to the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of a measuring device 1 according to the present invention. The measuring apparatus 1 performs various measurements on the device under test 100. The measuring device 1 includes a transmitter 10, a receiver 11, a signal generator 12, a signal analyzer 13, a controller 14, an output unit 15, and an input unit 16. The measuring apparatus 1 has a function as an AP that complies with the IEEE 802.11 standard.

  The DUT 100 is, for example, a transmission device such as a wireless LAN router when the STA operation is performed, or a STA-operated wireless LAN incorporated in a mobile terminal such as a smartphone or a laptop computer. The device under test 100 has a function as an STA that complies with the IEEE 802.11 standard.

  Further, the measurement device 1 and the DUT 100 are, for example, CSMA / CA based on the correspondence of a plurality of communication bandwidths standardized from IEEE802.11n, at the start of signal transmission / reception, depending on the signal quality of the channel. 1 has a function of a channel control process for changing the number of channels used for transmitting and receiving a signal between the device under test 100 and the device under test 100.

  When the signal is transmitted from the signal generating unit 12, the transmitting unit 10 transmits the transmitted signal to the DUT 100 by a wireless signal.

  When receiving the radio signal sent from the device under test 100, the receiving unit 11 sends the signal to the signal analyzing unit 13.

  The signal generation unit 12 generates a signal including a control packet and a data packet for communicating with the DUT 100, and transmits the signal to the DUT 100 via the transmission unit 10.

  The signal analysis unit 13 receives the signal sent from the DUT 100 via the reception unit 11, and detects the signal quality received by the power detection unit 30 that performs Power Detect and the signal detection unit 40 that performs Signal Detect. Analyze and perform CSMA / CA processing. Further, the signal analysis unit 13 measures the transmission / reception characteristics of the DUT 100 by the demodulation unit 70 and the measurement unit 80.

  The input unit 16 includes a plurality of hard keys to which a specific function such as a function key and a numeric keypad for setting measurement conditions and measurement contents is assigned, a rotary knob, and the like. Instead of the input unit 16, an input device such as a keyboard having a function key or a numeric keypad may be connected from the outside of the measuring device 1. One of the function keys arranged in the input unit 16 is a function key (OFF mode) described later. The operator can switch between the default mode and the OFF mode by operating the function key (OFF mode).

  The output unit 15 displays and outputs the content set by the input unit 16 and the measurement result measured by the measuring unit 80. In the example of the measuring apparatus 1 shown in FIG. 1, the output unit 15 is arranged inside the measuring apparatus 1, but a display device including a display screen or the like is provided from the outside of the measuring apparatus 1 instead of the output unit 15. It may take a form that can be connected.

  The control unit 14 includes, for example, a CPU (main processing circuit), a ROM (read-only memory), a RAM (random access memory), and the like, and performs overall control of each unit included in the measuring apparatus 1. Further, the control unit 14 sends a command for executing a specific process to the signal generation unit 12 and the signal analysis unit 13 based on the contents set by the operator operating the input unit 16.

  FIG. 2 is a diagram showing a detailed configuration of the signal analysis unit 13. The signal analysis unit 13 includes a power detection unit 30, a signal detection unit 40, a processing unit 50, a function storage unit 60, a demodulation unit 70, and a measurement unit 80.

  The power detection unit 30 and the signal detection unit 40 perform CSMA / CA processing integrally with the processing unit 50. The power detection unit 30 and the signal detection unit 40 are signals of a control packet RTS signal which is a use request signal transmitted from the DUT 100 when the measurement device 1 and the DUT 100 start transmitting and receiving a signal. The quality is analyzed using the received electric field strength of the signal, the level corresponding to the received electric field strength, the S / N, and the like. Here, the signal quality is measured using at least the received electric field strength of the signal and the S / N. The analysis result of the signal quality is sent to the processing unit 50, and the processing unit 50 receiving the analysis result creates a control packet CTS signal which is a use permission signal based on the analysis result, and sends the transmission unit 10 to the DUT 100. To send over.

  The demodulation unit 70 determines the channel for transmitting and receiving signals to and from the device under test 100 by the CSMA / CA processing of the power detection unit 30 and the signal detection unit 40, and then sends the data packet sent from the device under test 100. Of the transmission / reception characteristics of the DUT 100 such as packet error measurement, throughput measurement, EVM (Error Vector Magnitude) measurement, and the like. The transmission characteristics of the DUT 100 include, for example, transmission power, EVM, constellation, and the like. The reception characteristics of the DUT 100 include, for example, a packet error rate and a frame error rate.

  The measurement unit 80 issues an instruction to the demodulation unit 70 based on the measurement condition and the measurement content set by the input unit 16, and performs the measurement process of the transmission / reception characteristics of the DUT 100. The measuring section 80 also manages and stores the measured transmission / reception characteristics of the DUT 100. The function storage unit 60 stores a specific function set by the operator using the function keys, the ten keys, etc. of the input unit 16.

  The processing unit 50 cooperates with the power detection unit 30 and the signal detection unit 40, and, like CSMA / CA, the bandwidth used for transmitting and receiving signals to and from the DUT 100 according to the signal quality of the channel. Channel control processing to change the. The processing unit 50 includes information stored in the function storage unit 60 in which the content of the specific function set by the operator using the function keys of the input unit 16 is stored, the power detection unit 30, and the signal detection unit 40. The content of the response to the DUT 100 is determined based on the detection result sent from the device.

  In this channel control process, when the measuring apparatus 1 and the device under test 100 start transmitting and receiving signals, the device under test 100 transmits a control packet RTS signal, which is a use request signal of the channel of channel number A, to the channel number A. When the measurement apparatus 1 permits the use of the channel with the channel number A, the control packet CTS, which is the use permission signal, is measured using the channel with the channel number A. When the control packet CTS is transmitted to the device under test 100 and the use of the channel with the channel number A is not permitted, the control packet CTS is not transmitted to the device under test 100. The measuring apparatus 1 determines whether or not to permit use in response to a use request from the device under test 100 based on the signal quality of the channel.

  Furthermore, the channel control process has two modes, a default mode and an OFF mode. The default mode does not permit the use of the channel of the channel number A according to the signal quality of the channel A for the channel of the channel number A requested to be used by the device under test 100 according to the previous standard. It is a mode to perform. On the other hand, the OFF mode is a mode for measuring the DUT 100 as a measuring device, and is concerned with the signal quality of the channel of the channel number A with respect to the channel of the channel number A requested to be used by the DUT 100. It is a mode that permits use without use. The information on the mode of the channel control process is stored in the mode area 301 stored in the function storage unit 60.

  A function key (OFF mode) is arranged in the input unit 16, and the operator can switch between the default mode and the OFF mode by operating the function key (OFF mode).

  FIG. 3 is a diagram showing an example of bit assignment of the mode area 301 stored in the function storage unit 60. The channel control bit (b7) is a bit indicating the mode of channel control processing. A value of 1 for the channel control bit indicates that the mode of the channel control process is the OFF mode, and a value of 0 for the channel control bit indicates that the mode of the channel control process is the default mode.

  When changing the channel control processing mode from the default mode to the OFF mode, the operator presses the function key (OFF mode). When the operator presses the function key (OFF mode), the input unit 16 sends a command for changing the mode to the OFF mode to the processing unit 50 of the signal analysis unit 13 via the control unit 14. Upon receiving the command to change to the OFF mode, the processing unit 50 sets the channel control bit (b7) of the mode area 301 to 1 (OFF mode). As a result, the measurement apparatus 1 can permit the use of the channel number A requested to be used by the device under test 100 regardless of the signal quality of the channel number A in the channel control process.

  When returning the mode of the channel control processing from the OFF mode to the default mode, the operator releases the function key (OFF mode) in the pressed state again. When the operator releases the function key (OFF mode), the input unit 16 sends a command for changing to the default mode to the processing unit 50 via the control unit 14. Upon receiving the command to change to the default mode, the processing unit 50 sets the channel control bit (b7) of the mode area 301 to 0 (default mode).

  The processing in the OFF mode of the channel control processing in the embodiment of the measuring apparatus according to the present invention will be described below with reference to FIGS. 4 to 6.

  FIG. 4 shows a case where it is determined that no channel collision has occurred in the channel requested by the DUT, as a result of confirmation of the signal quality of the channel in the channel control processing in the embodiment of the measuring apparatus according to the present invention. FIG. 3 is a diagram showing transmission and reception of signals (control packets).

  4A shows the timing when the measuring apparatus 1 transmits a signal (control packet), and FIG. 4B shows the timing when the DUT STA-A transmits a signal (control packet). The horizontal axis represents time, and the vertical axis represents channels used by the measuring apparatus 1 and the object to be measured STA-A. The channels are numbered, and there are four channels with channel numbers 52, 56, 60, 64 as shown in FIGS. 4 (A) and 4 (B). The measurement device 1 and the device under test STA-A are divided into two in FIG. 4 (A) and FIG. 4 (B) in order to make it easy to understand the timing at which the channels are used. Is.

  In each channel, the part enclosed by □ represents the signal (control packet) sent by the measuring apparatus 1 or the device under test STA-A at the input / output end of the measuring apparatus and its transmission timing. For example, “RTS80 MHz” represented by the channel numbers 52, 56, 60, 64 of the device under test STA-A is 20 MHz × 4 = 80 MHz of the device under test STA-A having channel numbers 52, 56, 60, 64. In order to request the use of the bandwidth, the control device RTS, which is the use request signal for the 80 MHz band of the channel numbers 52, 56, 60, 64, is transmitted to the measuring device 1 at the timing of time t1. It indicates that the transmission is performed using the channels of 56, 60, and 64. In the "DATA 80 MHz band" represented by the channel numbers 52, 56, 60, 64 of the device under test STA-A, the device under test STA-A receives channel numbers 52, 56, 60, 64 from the measuring apparatus 1. It is shown that the data packet is transmitted to the measuring apparatus 1 at the timing of time t3 with the bandwidth of 80 MHz using the channel numbers 52, 56, 60, 64 after being permitted to use the 80 MHz band. There is.

  When the device under test STA-A starts transmitting and receiving a signal to and from the measuring device 1, the device under test STA-A uses the measuring device 1 as a use request signal of 80 MHz bandwidth of channel numbers 52, 56, 60 and 64. The control packet RTS is transmitted for each requested channel. The measuring apparatus 1 that has received the control packet RTS for each channel confirms whether channel collision has occurred in the channel requested to be used. When the measurement apparatus 1 determines that the channel collision has not occurred, the measurement device STA-A sends a control packet CTS for each permitted channel to the DUT STA-A as a use permission signal of the channel requested by the DUT STA-A. To send. FIG. 4A is an example in which the measuring apparatus 1 transmits the control packet CTS to the DUT STA-A at the timing of time t2. The device under test STA-A receiving the control packet CTS recognizes that the channel receiving the control packet CTS is permitted to be used, and thereafter transmits the data packet and the control packet to the measuring apparatus 1 using the permitted channel. .

  FIG. 5 shows a case in which it is determined that a channel collision has occurred in a channel requested by the device under test as a result of confirmation of the signal quality of the channel in the channel control process in one embodiment of the measuring apparatus according to the present invention. FIG. 3 is a diagram showing transmission and reception of signals (control packets).

  The vertical axis, the horizontal axis, and the channels in FIGS. 5A, 5B, and 5C are the same as those in FIGS. 4A and 4B. The difference from FIG. 4 is that STA-B is added in addition to the measured object STA-A. When the device under test STA-A starts transmitting and receiving a signal to and from the measuring device 1, the device under test STA-A uses the measuring device 1 as a use request signal of 80 MHz bandwidth of channel numbers 52, 56, 60 and 64. The control packet RTS is transmitted for each requested channel. Further, it is assumed that STA-B simultaneously transmits a control packet RTS for each channel requesting use to the measuring apparatus 1 as a use request signal of 40 MHz bandwidth of channel numbers 60 and 64. The measurement device 1 that has received the control packet RTS for each channel confirms whether channel collision has occurred in the requested channel. Since the control packets RTS from the DUTs STA-A and STA-B have been sent to the channels with the channel numbers 60 and 64, the measuring apparatus 1 has the channel numbers 60 and 64 among the channels requested to be used. It is determined that a channel collision has occurred in the channel.

  The measurement apparatus 1 that has determined that the channel collision has occurred determines whether the mode of the channel control processing is the default mode or the OFF mode when permitting the use of the requested channel. This is confirmed by referring to the value of the channel control bit (b7) of. In the case of FIG. 5A, it is assumed that the value of the channel control bit (b7) is 0 (default mode). In this case, the measuring apparatus 1 transmits the control packet CTS to the DUT STA-A on the channels with the channel numbers 52 and 56 excluding the channel numbers 60 and 64 which are determined to have channel collisions. .. FIG. 5A is an example in which the measuring apparatus 1 transmits the control packet CTS to the DUT STA-A at the timing of time t5 using the channels of channel numbers 52 and 56.

  The device under test STA-A, which has received the control packet CTS sent from the measuring apparatus 1 through the channels of channel numbers 52 and 56, recognizes that the use of the channels of channel numbers 52 and 56 is permitted, and the data packet and The control packet is transmitted to the measuring device 1 using the permitted channel. FIG. 5B is an example in which the device under test STA-A transmits a data packet to the measuring apparatus 1 using the channels of channel numbers 52 and 56 at the timing of time t6.

  FIG. 6 shows a case where it is determined that channel collision has occurred in the channel requested by the DUT as a result of confirmation of the signal quality of the channel in the channel control process in the embodiment of the measuring apparatus according to the present invention. FIG. 3 is a diagram showing transmission and reception of signals (control packets). The difference from FIG. 5 is that the measuring apparatus 1 judges that a channel collision has occurred in the channels of channel numbers 60 and 64 that the device under test STA-A requires to use, but refer to the channel control bit (b7). As a result, the measuring apparatus 1 notifies all the channels requested by the device under test STA-A of the permission of use. In the case of FIG. 6A, the value of the channel control bit (b7) is 1 (OFF mode).

  The measuring apparatus 1 that has determined that the channel collision has occurred confirms whether the mode of the channel control processing is the default mode or the OFF mode by referring to the value of the channel control bit (b7) in the mode area 301. To do. In the case of FIG. 6A, since the value of the channel control bit (b7) is 1 (OFF mode), the measuring apparatus 1 causes the measured object STA-A to perform channel collision in addition to channel 52 and channel 56. The control packet CTS is also transmitted as a use permission signal to the channels with the channel numbers 60 and 64 which are determined to have occurred.

  7A to 7E are processing flows of channel control processing in the embodiment of the measurement apparatus according to the present invention.

  FIG. 7A is an overall processing flow of channel control processing in an embodiment of the measuring apparatus according to the present invention. The overall channel control processing includes signal reception (request notification reception) (S71), RTS analysis processing (S700), and signal transmission (permission notification transmission) (S72). In FIG. 7A, the measurement apparatus 1 receives a signal from the DUT 100 at the receiving unit 11 when starting transmission / reception of the signal to / from the DUT 100 (S71), and analyzes the received signal. It is transmitted to the section 13. Upon receiving the signal, the signal analysis unit 13 causes the power detection unit 30 and the signal detection unit 40 to start the RTS analysis processing (S700) of the received signal. The signal analysis unit 13 performs an RTS analysis process on the received signal for each of the bandwidths of Primary 20 MHz, Secondary 20 MHz, and Secondary 40 MHz that are predetermined with the DUT 100.

  FIG. 7B is an overall processing flow of the RTS analysis processing in the channel control processing in the embodiment of the measurement apparatus according to the present invention. The signal analysis unit 13 performs the RTS analysis process in parallel for each of the bandwidths of Primary 20 MHz, Secondary 20 MHz, and Secondary 40 MHz that are predetermined between the measurement apparatus 1 and the DUT 100 (S700A, S700B, S700C). The processing flow of the Primary 20 MHz analysis processing (S700A) is shown in FIG. 7C, the processing flow of the Secondary 20 MHz analysis processing (S700B) is shown in FIG. 7D, and the processing flow of the Secondary 40 MHz analysis processing (S700C) is shown in FIG. 7E. Here, it is assumed that Primary 20 MHz is the channel with channel number 56, Secondary 20 MHz is the channel with channel number 52, and Secondary 40 MHz is the channel with channel numbers 60 and 64. Further, it is assumed that the DUT 100 requests the use of four channels of channel numbers 52, 56, 60, 64.

  FIG. 7C is a processing flow of the Primary 20 MHz analysis processing (S700A) performed by the signal analysis unit 13. The power detection unit 30 calculates the received electric field strength of the signal of the channel of the channel number 56, which is the primary 20 MHz channel transmitted from the reception unit 11. In order to analyze the channel of Primary 20 MHz sent from the receiver 11, the signal detector 40 sets the band pass filter to the channel of channel number 56 which is the channel of Primary 20 MHz (S701), and receives the band pass filter. The filtered signal is passed through a bandpass filter.

  The filter unit 41 sends the signal that has passed through the bandpass filter to the preamble detection unit 42. The preamble detection unit 42 detects the preamble of the signal sent from the filter unit 41 (S702). When the preamble can be detected (Y in S703), the preamble detector 42 requests the power detector 30 for the received electric field strength of the signal of the channel with the channel number 56 which is Primary 20 MHz. The preamble detection unit 42, which has acquired the requested received electric field strength from the power detection unit 30, confirms the acquired received electric field strength (S704) and compares the value with the value of Signal threshold (S705). As a result of comparison, when the received electric field strength of the signal of the channel of channel number 56 which is Primary 20 MHz is equal to or higher than the Signal threshold (S705 Y), the preamble detection unit 42 sends the received signal to the header demodulation unit 43.

  The header demodulation unit 43 that has received the signal demodulates the header (S706). When the header demodulation unit 43 can demodulate the header (Y in S707), the header demodulation unit 43 sends the received signal to the processing unit 50.

  The processing unit 50 that has received the signal has a channel number 56 that is a channel of Primary 20 MHz that the device under test 100 has requested to use, a channel number 52 that is a channel of Secondary 20 MHz, and a channel number 60 that is a channel of Secondary 40 MHz, Since the control packet CTS, which is the use permission signal for the 64 channels, is transmitted using the channel numbers 52, 56, 60, and 64 that are the channels requesting the use, the permission notification management table 901 (managed by the processing unit 50 The CTS transmission status of the Primary 20 MHz channel (described later), the CTS transmission status of the Secondary 20 MHz channel, and the CTS transmission status of the Secondary 40 MHz channel are set to ON (S708), and the Primary 20 MHz analysis processing of the received signal ends (S709).

  The processing unit 50 controls the processing unit 50 to update the CTS transmission status of the permission notification management table 901 in the order of update by the Primary 20 MHz analysis process, update by the Secondary 20 MHz analysis process, and update by the Secondary 40 MHz analysis process. To do.

  On the other hand, when the preamble cannot be detected in the process of S703 (S703 N) and the comparison in the process of S705 is performed, the preamble detection unit 42 finds that the reception electric field strength of the signal of the channel with the channel number 56, which is the channel of Primary 20 MHz, is When it is less than the Signal threshold (S705 N), the result is notified to the processing unit 50, and the processing unit 50 that has received the result notification receives the result notification, and the processing unit 50 sets the channel number 56 of the primary 20 MHz channel in the permission notification management table 901 (described later) The CTS transmission status of the channel is set to OFF (S711), and the primary 20 MHz analysis processing of the received signal is ended (S709).

  Further, when the header demodulation unit 43 cannot detect the header in the process of S707 (S707 N), the header demodulation unit 43 requests the power detection unit 30 for the received electric field strength of the signal of the channel of channel number 56 which is the primary 20 MHz channel. To do. The header demodulation unit 43, which has acquired the requested received electric field strength from the power detection unit 30, compares the value with the energy threshold (S710).

  As a result of the comparison, when the received electric field strength of the signal of the channel of the channel number 56 which is Primary 20 MHz is less than the energy threshold (S710 N), the CTS transmission of the Primary 20 MHz channel of the permission notification management table 901 (described later) managed by the processing unit 50 is performed. The status is set to OFF (S711), and the primary 20 MHz analysis processing of the received signal is ended (S709).

  FIG. 7D is a processing flow of the Secondary 20 MHz analysis processing (S700B) performed by the signal analysis unit 13. The power detection unit 30 calculates the received electric field strength of the signal of the channel of channel number 52, which is the Secondary 20 MHz channel transmitted from the reception unit 11. The signal detection unit 40 analyzes the channel of the channel number 52, which is the channel of Secondary 20 MHz transmitted from the reception unit 11.

  In order to analyze the Secondary 20 MHz channel sent from the receiving unit 11, the signal detecting unit 40 sets the bandpass filter to the channel of channel number 52 which is the Secondary 20 MHz channel (S721), and receives the signal. The filtered signal is passed through a bandpass filter.

  Hereinafter, the Secondary 20 MHz analysis processing is the same as the corresponding processing of S704 to S710 of the Primary 20 MHz analysis processing except for S724, S725, S728, S730, S731 and S732. The reception electric field strength acquired from the power detection unit 30 in S724 is the reception electric field strength of the channel of channel number 52 which is the channel of Secondary 20 MHz. Signal threshold and Energy threshold at the time of performing the comparison process of S725 and S730 are both values for Secondary 20 MHz. The process of S728 is a process of setting the CTS transmission status of the Secondary 20 MHz channel and the CTS transmission status of the Secondary 40 MHz channel to ON. The process of S731 is a process of confirming whether the value of the permission notification management table has been updated by the process of S708 of FIG. 7C. When the processing unit 50 confirms that the CTS transmission status of the Primary 20 MHz channel is set to ON by the processing of S708, the processing unit 50 does not perform the processing of S732. The process of S732 is a process of setting the CTS transmission status of the Secondary 20 MHz channel to OFF.

  Further, FIG. 7E is a processing flow of the Secondary 40 MHz analysis processing (S700C) performed by the signal analysis unit 13. The power detection unit 30 calculates the received electric field strength of the signals of the channels of channel numbers 60 and 64, which are the channels of Secondary 40 MHz transmitted from the reception unit 11. The signal detection unit 40 analyzes the channels of the channel numbers 60 and 64 which are the channels of Secondary 40 MHz sent from the reception unit 11.

  In order to analyze the Secondary 40 MHz channel sent from the receiving unit 11, the signal detecting unit 40 sets the bandpass filter to the channels of channel numbers 60 and 64 that are Secondary 40 MHz channels (S741). , Pass the received signal through a bandpass filter.

  After that, the Secondary 40 MHz analysis processing is the same as the corresponding processing from S704 to S710 of the Primary 20 MHz analysis processing, except for S744, S745, S748, S750, S751, and 752. The received electric field strength acquired from the power detection unit 30 in S744 is the received electric field strength of the channels of channel numbers 60 and 64 which are the channels of Secondary 40 MHz. The signal threshold and the energy threshold at the time of performing the comparison processing of S745 and S750 are both values for Secondary 40 MHz. The process of S748 is a process of setting the CTS transmission status of the Secondary 40 MHz channel to ON. The process of S751 is a process of confirming whether the value of the permission notification management table has been updated by the process of S708 or S728 of FIG. 7C. When confirming that the CTS transmission status of the Primary 20 MHz channel is set to ON by the processing of S708, the processing unit 50 does not perform the processing of S752. The process of S752 is a process of setting the CTS transmission status of the Secondary 40 MHz channel to OFF.

  When the primary 20 MHz analysis processing, the secondary 20 MHz analysis processing, and the secondary 20 MHz analysis processing are completed, the processing unit 50 performs the mode confirmation processing (S800) and the CTS creation processing (S1000).

  FIG. 8 is a mode confirmation processing flow for confirming the mode of the channel control processing in the embodiment of the measurement apparatus according to the present invention (S800). When the setting of the CTS transmission status of the permission notification management table 901 is completed based on the signal analysis results performed by the power detection unit 30 and the signal detection unit 40, the processing unit 50 starts the mode confirmation processing (S800). The processing unit 50 confirms the currently set channel control processing mode by referring to the channel control bit (b7) of the mode area 301 (S801).

  When the channel control bit (b7) is 1 (OFF mode), the processing unit 50 sets the CTS creation status of the Primary 20 MHz channel, the CTS creation status of the Secondary 20 MHz channel, and the CTS creation status of the Secondary 40 MHz channel of the permission notification management table 901 to ON. (S803), and the mode confirmation process ends (S804). That is, the processing unit 50 sets all the CTS creation statuses to ON so that the measuring device 1 measures the DUT 100.

  When the channel control bit (b7) is 0 (default mode), the processing unit 50 sets the value of the CTS transmission status of the Primary 20 MHz channel to the CTS creation status of the Primary 20 MHz channel of the permission notification management table 901, and creates the CTS of the Secondary 20 MHz channel. The value of the CTS transmission status of the Secondary 20 MHz channel is set in the status, the value of the CTS transmission status of the Secondary 40 MHz channel is set in the CTS creation status of the Secondary 40 MHz channel (S805), and the mode confirmation processing ends (S804). That is, the processing unit 50 is the channel with the primary 20 MHz and the channel number 52, which is the channel with the channel number 56 shown in FIGS. 7C to 7E, in the CTS creation status in order for the measuring device 1 to make the determination according to the conventional standard. A CTS transmission status, which is an analysis result of RTS for each bandwidth of Secondary 40 MHz, which is a channel of Secondary 20 MHz and channel numbers 60 and 64, is set.

  FIG. 9 is a diagram showing an example of the permission notification management table 901 and its set values. The vertical axis represents the status type and the horizontal axis bandwidth (Primary 20 MHz / Secondary 20 MHz / Secondary 40 MHz). The initial setting value of the table is OFF. The permission notification management table 901 exists in the processing unit 50 and is managed by the processing unit 50.

  As the CTS transmission status, as described in the processing flow of FIG. 7, as a result of the confirmation of the signal quality of the channel by the power detection unit 30 and the signal detection unit 40, the control packet CTS which is the use permission signal cannot be transmitted. It shows the state. When the CTS transmission status is set to ON, the control packet CTS can be transmitted, and when the CTS transmission status is set to OFF, the control packet CTS cannot be transmitted.

  The CTS creation status indicates that the control packet CTS is not created based on the value of the channel control bit (b7) regardless of the result of confirmation of the signal quality of the channel by the power detection unit 30 and the signal detection unit 40. There is. When the CTS creation status is set to ON, it indicates that the control packet CTS is created, and when the CTS creation status is set to OFF, it indicates that the control packet CTS is not created.

  In FIG. 9A, the CTS transmission status is set to OFF in S711 of FIG. 7C and S732 of FIG. 7D, the CTS transmission status is set to ON in S748 of FIG. 7E, and the CTS creation status is set in S805 of FIG. It is an example of the setting value of the permission notification management table 901 set to the value of the CTS transmission status.

  In FIG. 9B, similarly, the CTS status is set to OFF in S711 of FIG. 7C and S732 of FIG. 7D, the CTS transmission status is set to ON in S748 of FIG. 7E, and the CTS creation status is set in S803 of FIG. It is an example of the setting value of the permission notification management table 901 set to ON. The CTS creation status is all ON regardless of the value of the CTS transmission status.

  FIG. 10 shows a control packet RTS, which is a use request signal sent from the device under test 100, according to the value of the CTS creation status of the permission notification management table 901 in the embodiment of the measuring apparatus according to the present invention. It is a processing flow for creating a control packet CTS which is a use permission signal (S1000).

  The processing unit 50 refers to the CTS creation status of the Primary 20 MHz channel, the CTS creation status of the Secondary 20 MHz channel, and the CTS creation status of the Secondary 40 MHz channel stored in the permission notification management table 901 (S1001), and the CTS creation status is set to ON. The channel that is open is confirmed (S1002).

  As a result of the confirmation, for the channel for which the CTS creation status is set to ON, the processing unit 50 creates the control packet CTS which is the use permission signal of the channel (S1003), and ends the CTS creation process (S1003). S1004). As a result of the confirmation, for the channel for which the CTS creation status is set to OFF, the processing unit 50 does not create the control packet CTS that permits the use of the channel (S1005) and ends the CTS creation process. (S1004).

  The processing unit 50 sends the created control packet CTS to the signal generation unit 12 via the control unit 14. The signal generator 12 generates a signal including the control packet CTS sent from the controller 14, and sends it from the transmitter 10 to the device under test 100 using the channel requested to be used by the device under test 100. (S72).

  As a result, the measuring apparatus 1 has a function of permitting the use of the channel to be measured by the DUT 100 regardless of the signal quality of the channel.

  In the above description, the case where the channel control process has two modes of the default mode and the OFF mode has been described, but the channel control process may have three or more modes. In this case, 2 bits may be assigned to the channel control bits of the mode area 301, for example.

  FIG. 11 shows another example of bit assignment of the mode area 301 in the function storage unit 60. An example of bit assignment of the mode area 301 when there are OFF mode 1 and OFF mode 2 in addition to the default mode is shown. Channels b7 to b6 are channel control bits indicating the mode of channel control processing. In the OFF mode 1, for example, for the 80 MHz bandwidth of the channel numbers 52, 56, 60, 64 requested to be used by the DUT 100, the channel numbers 52, 56, 60, 64 are irrespective of the signal quality of the channels. This is a mode that permits the use of the 80 MHz bandwidth of In the OFF mode 2, for example, with respect to the channel requested to be used by the device under test 100, only the channel of channel number 56, which is the channel of Primary 20 MHz requested to be used, determines the signal quality and permits the use. It is a mode in which use is permitted for the channel having the channel number 52 and the channel having the channel numbers 60 and 64 having the Secondary 40 MHz regardless of the signal quality.

  FIG. 12 is another example of the mode confirmation processing flow for confirming the mode of the channel control processing in the embodiment of the measurement apparatus according to the present invention. 12 shows an example of a mode confirmation processing flow when the modes of the channel control processing are the three modes of the default mode, OFF mode 1 and OFF mode 2 shown in FIG.

  The processing of S1201 to S1205 is the same as the corresponding processing of S801 to S805 of FIG. The processing of FIG. 12 is processing for determining the OFF mode 2 (S1206) with respect to the processing of FIG. 8 and the permission notification management table 901 when the mode set in the measurement device 1 is the OFF mode 2 as a result of the determination. The process for setting the status to the CTS creation status (S1207) is added. In the process of S1207, the CTS creation status of the Primary 20 MHz channel is set to the CTS creation status of the Primary 20 MHz channel, and the CTS creation status of the Secondary 20 MHz channel and the CTS creation status of the Secondary 40 MHz channel are set to ON. As a result, the measurement apparatus 1 permits the use of the Primary channel requested to be used according to the signal quality of the channel, and the other channels to use the requested channel regardless of the signal quality of the channel requested to be used. Will be allowed.

  Further, the channel control processing in the embodiment of the measuring apparatus according to the present invention is also applicable to the case of permitting the use of the channel to the DUT that requires only one channel as the channel requesting the use. .. In this case, the measuring apparatus 1 may notify the permission of use to one channel requested to be used according to the value of the channel control bit.

  As described above, the measuring apparatus 1 according to the present embodiment can permit the use of the channel requested by the DUT 100 regardless of the signal quality of the channel. As a result, the measurement apparatus 1 can enable the packet error rate and the throughput measurement in the channel that the device under test 100 requires to use.

  Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto. Furthermore, in each of the constituent elements in the claims, the constituent elements are expressed in a divided manner, a plurality of constituent elements are expressed together, or a combination thereof is also included in the scope of the present invention. Further, the device of the present invention is applied even when the claims are expressed as control logic, when expressed as a program including instructions for executing a computer, and when expressed as a computer-readable recording medium in which the instructions are described. is there. Also, the names and terms used are not limited, and other expressions are included in the present invention as long as they have substantially the same content and meaning.

DESCRIPTION OF SYMBOLS 1 ... Measuring device, 10 ... Transmission part, 11 ... Reception part, 12 ... Signal generation part, 13 ... Signal analysis part, 14 ... Control part, 15 ... Output part , 16 ... Input unit, 30 ... Power detection unit, 40 ... Signal detection unit, 50 ... Processing unit, 60 ... Function storage unit, 70 ... Demodulation unit, 80 ... -Measuring part, 100 ... Object to be measured.

Claims (10)

A measurement device (1) for transmitting and receiving a signal to and from a device under test (100) using a wireless line composed of a plurality of channels to measure the transmission / reception characteristics of the device under test,
A receiving unit (11) for receiving a use request signal for each channel using a use request channel transmitted from the device under test when starting transmission and reception of the signal;
A signal analysis unit (13) for analyzing the signal quality of each channel based on the received use request signal of each channel;
A processing unit (50) for deciding whether or not to permit use of a channel requested to be used by the use request signal based on a result of analyzing the signal quality;
A transmission unit (10) that transmits a use permission signal for each channel using the use request channel that the processing unit has decided to permit use of;
A function storage unit (60) in which control mode information designating whether or not to permit the use of each channel based on the signal quality of each channel is stored;
Equipped with
The processing unit determines whether to permit use for each channel based on the signal quality of each channel as a result of analyzing the signal quality and the control mode information stored in the function storage unit. Decide each,
The measurement apparatus, wherein the signal analysis unit measures the transmission / reception characteristics of the device under test using a channel for which the processing unit has determined permission to use the channel.   The measurement device according to claim 1, wherein the use request signal for each channel is transmitted on a channel continuously used in a bandwidth supported by the device under test.   The control mode information, for the use request signal for each of the plurality of channels transmitted from the DUT, regardless of the signal quality of the plurality of channels, for all the channels requested for use The measuring device according to claim 2, further comprising a mode for permitting use.   The measurement device according to claim 1, wherein the control mode information stored in the function storage unit is rewritable.   The signal analysis unit uses at least the received electric field strength and the S / N of the signal sent from the device under test when measuring the signal quality of each channel. The measuring device according to claim 4. Using a wireless line composed of a plurality of channels, transmitting and receiving signals to and from the DUT, a measurement method for measuring the transmission and reception characteristics of the DUT,
When starting the transmission and reception of the signal, receiving the use request signal for each channel using the use request channel transmitted from the DUT,
Analyzing the signal quality for each channel based on the received request signal for each channel,
Saving the control mode information for specifying whether or not to permit the use of each channel based on the signal quality of each channel in the control mode information storage area,
Based on the signal quality of each channel as a result of the analysis of the signal quality and the control mode information stored in the control mode information storage area, it is determined whether or not to permit the use for each channel. The measuring method is characterized in that the transmission / reception characteristics of the device under test are measured using the channel for which the use permission has been determined.   7. The measurement method according to claim 6, wherein the use request signal for each channel is transmitted on a channel that is continuously used in a bandwidth supported by the device under test.   The control mode information, for the use request signal for each of the plurality of channels transmitted from the DUT, regardless of the signal quality of the plurality of channels, for all the channels requested for use The measuring method according to claim 7, further comprising a mode of permitting use.   9. The measuring method according to claim 6, wherein the control mode information stored in the control mode information storage area is rewritable.   The analysis of the signal quality for each channel is characterized in that, when measuring the signal quality for each channel, at least the received electric field strength and S / N of the signal sent from the DUT are used. The measuring method according to any one of claims 6 to 9.

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