WO2021176516A1

WO2021176516A1 - Wireless communication device, wireless communication system, control circuit, storage medium, and radio wave monitoring method

Info

Publication number: WO2021176516A1
Application number: PCT/JP2020/008692
Authority: WO
Inventors: 和雅鈴木
Original assignee: 三菱電機株式会社
Priority date: 2020-03-02
Filing date: 2020-03-02
Publication date: 2021-09-10
Also published as: JP7045533B2; JPWO2021176516A1

Abstract

A wireless communication device according to the present invention, which is a first wireless communication device in a wireless communication system in which the first wireless communication device wirelessly communicates with a second wireless communication device with the distance therebetween varying, comprises: a first interference measuring unit (105) that measures an interference power during a non-transmission section that is a specified time period immediately before or immediately after receipt of a wireless packet, thereby outputting a first interference power measurement result; a second interference measuring unit (106) that measures an interference power by use of null symbols dispersed in the wireless packet, thereby outputting a second interference power measurement result; and a selection unit (107) that, on the basis of the distance between the second wireless communication device and the wireless communication device, selects and outputs at least one of the first interference power measurement result or the second interference power measurement result.

Description

Wireless communication devices, wireless communication systems, control circuits, storage media and radio wave monitoring methods

The present disclosure relates to a wireless communication device for measuring a radio wave environment, a wireless communication system, a control circuit, a storage medium, and a radio wave monitoring method.

Since frequencies are a finite resource, it is difficult to allocate new frequencies exclusively when constructing a new wireless communication system. The 2.4 GHz band ISM (Industry-Science-Medical) band is easy to use in new wireless communication systems because anyone can use it without a license if it meets certain technical standards. On the other hand, in the ISM band, various wireless communication systems coexist, and radio waves from other systems can be jamming radio waves for the own system, so that the radio wave environment is not necessarily good. Therefore, it is important to keep track of the radio wave environment during operation in order to operate the wireless communication system in a stable manner. If the radio wave environment can be grasped, it is possible to take measures such as refraining from using frequency channels with poor communication quality and changing the antenna installation position when the radio wave environment deteriorates.

In grasping the radio wave environment such as interference waves from other systems, it is not desirable to install a new device from the viewpoint of cost, and it is desirable that the device used in the own system can also measure the radio wave environment. Patent Document 1 describes a technique in which a wireless communication device scans each frequency channel used in its own system in order before communication, selects a good channel as a radio wave environment with few interfering waves, and performs wireless communication with an opposite wireless device. Is disclosed.

Japanese Patent No. 4861920

In order to measure the radio wave environment, it is necessary to measure at the time and frequency when the own system is not communicating. However, there is a problem that it is not desirable from the viewpoint of frequency utilization efficiency to provide a dedicated time for measurement as in Patent Document 1. This is because the wireless communication system cannot transmit information, which is the original purpose, during the measurement. In particular, wireless communication systems that control moving objects using wirelessly transmitted information must always perform wireless transmission at regular intervals, and are dedicated to measuring the radio wave environment with high communication frequency. It is difficult to set the time for.

The present disclosure has been made in view of the above, and an object of the present invention is to obtain a wireless communication device capable of improving the measurement accuracy of the radio wave environment while suppressing the use of time and frequency for measuring the radio wave environment. ..

In order to solve the above-mentioned problems and achieve the object, the present disclosure discloses the first radio in a wireless communication system in which a first wireless communication device and a second wireless communication device perform wireless communication while changing the distance. It is a wireless communication device that is a communication device. The wireless communication device has a first interference measuring unit that measures interference power in a non-transmission section for a specified period immediately before or immediately after receiving a wireless packet and outputs a first interference power measurement result, and a wireless communication device. Based on the distance between the second wireless communication device and the wireless communication device, the interference power is measured by the null symbols distributed in the packet, and the second interference measurement unit that outputs the second interference power measurement result is output. It is characterized by including a selection unit that selects and outputs at least one of a first interference power measurement result and a second interference power measurement result.

The wireless communication device according to the present disclosure has the effect of improving the measurement accuracy of the radio wave environment while suppressing the use of time and frequency for measuring the radio wave environment.

The figure which shows the configuration example of the wireless communication system which concerns on this Embodiment Block diagram showing a configuration example of a mobile station according to this embodiment The figure which shows the state of the wireless transmission between the base station and the mobile station which concerns on this embodiment. The figure which shows the example of the radio packet sent and received between the base station and the mobile station which concerns on this embodiment. The figure which shows the example of the data part included in the radio packet transmitted and received between the base station and the mobile station which concerns on this Embodiment. The figure which shows the leakage from the adjacent subcarrier in the power measurement by the null symbol which concerns on this embodiment. The figure which shows the example of the interference power measurement result stored in the radio wave environment monitoring apparatus which concerns on this embodiment. A flowchart showing the operation of the mobile station according to the present embodiment. The figure which shows the structural example of the processing circuit when the processing circuit provided in the mobile station which concerns on this Embodiment is realized by a processor and a memory. The figure which shows the example of the processing circuit when the processing circuit provided in the mobile station which concerns on this Embodiment is configured by the dedicated hardware.

Hereinafter, the wireless communication device, the wireless communication system, the control circuit, the storage medium, and the radio wave monitoring method according to the embodiment of the present disclosure will be described in detail with reference to the drawings.

Embodiment.
FIG. 1 is a diagram showing a configuration example of the wireless communication system 10 according to the present embodiment. The wireless communication system 10 includes

mobile stations

1a, 1b, 1c,

cages

2a, 2b, 2c,

base stations

3a, 3b, 3c,

hoistways

4a, 4b, 4c, a wired network 5, and a radio wave environment monitoring device. 6 and. In the wireless communication system 10, a mobile station 1a, a car 2a, a base station 3a, and a hoistway 4a constitute a control system for one elevator. Similarly, the mobile station 1b, the car 2b, the base station 3b, and the hoistway 4b constitute one elevator control system, and the mobile station 1c, the car 2c, the base station 3c, and the hoistway 4c constitute one elevator. It constitutes the control system of. In the wireless communication system 10, the mobile station 1a and the base station 3a perform one-to-one wireless communication, the mobile station 1b and the base station 3b perform one-to-one wireless communication, and the mobile station 1c and the base station 3c perform one pair. Wireless communication is performed in 1.

In the following description, when the

mobile stations

1a, 1b and 1c are not distinguished, they are referred to as mobile stations 1, when the

baskets

2a, 2b and 2c are not distinguished, they are referred to as baskets 2, and when the

base stations

3a, 3b and 3c are not distinguished. Is referred to as a base station 3, and may be referred to as a hoistway 4 when the

hoistways

4a, 4b, and 4c are not distinguished. In the wireless communication system 10 shown in FIG. 1, there are three hoistways 4, that is, elevator control systems, but this is an example and may be two or less or four or more.

Mobile station 1 is a wireless communication device installed on the car 2. The mobile station 1 transmits information such as the position information of the car 2 and the button operation information in the car 2 to the base station 3.

In the elevator, the car 2 moves up and down in the hoistway 4 by a hoist (not shown) according to the control from the elevator control panel (not shown).

The base station 3 is a wireless communication device in which an antenna is installed on the ceiling in the hoistway 4 and is connected to an elevator control panel in a machine room (not shown) on the ceiling of the hoistway 4. The base station 3 transmits instructions such as opening and closing of the door, floor number display information, and the like to the mobile station 1 according to the information from the elevator control panel.

The hoistway 4 is a path through which the car 2 moves in the vertical direction. In the example of FIG. 1, it is assumed that there are three hoistways 4 in one building.

The wired network 5 is a network to which the base station 3 is connected. The wired network 5 is used to collect information from each base station 3 in the radio wave environment monitoring device 6.

The radio wave environment monitoring device 6 aggregates information on the radio wave environment measured by the mobile station 1, the base station 3, and the like. The radio wave environment is, for example, interference power indicating the amount of interference in the mobile station 1, the base station 3, and the like.

The wireless communication system 10 is a wireless communication system in which the mobile station 1 and the base station 3 perform wireless communication while changing the distance. In the present embodiment, the wireless communication system 10 is an example of a system in which control information is transmitted by wireless communication, unlike a conventional elevator in which control information is exchanged between the car 2 and the machine room described above by a control cable. However, the present invention is not limited to this. The wireless communication system 10 is another radio in which the mobile station 1 moves along a certain travel path while the distance between the mobile station 1 and the base station 3 changes, and the received signal level changes according to the distance. It can also be applied to communication systems.

The configuration of the mobile station 1 and the base station 3 will be described. In the present embodiment, since the mobile station 1 and the base station 3 have the same configuration, the mobile station 1 will be described as an example. FIG. 2 is a block diagram showing a configuration example of the mobile station 1 according to the present embodiment. The mobile station 1 includes an antenna 101, an RF (Radio Frequency) unit 102, a modulation / demodulation processing unit 103, a transmission / reception control unit 104, a first interference measurement unit 105, a second interference measurement unit 106, and a selection unit. 107 and.

The antenna 101 radiates a radio signal into the air at the time of transmission and receives the radio signal propagating in the air.

When transmitting a radio signal, the RF unit 102 converts the digitally modulated signal into an analog signal and frequency-converts it into a carrier frequency. Further, when receiving a radio signal, the RF unit 102 frequency-converts the analog signal received from the antenna 101 into a baseband and converts it into a digital signal.

The modulation / demodulation processing unit 103 performs signal processing such as coding and modulation on the transmitted data at the time of transmission, and performs signal processing such as demodulation and decoding on the received signal at the time of reception.

The transmission / reception control unit 104 controls the transmission / reception of signals. Further, the transmission / reception control unit 104 controls to transmit the interference power measurement result measured by the first interference measurement unit 105 and the second interference measurement unit 106 and selected by the selection unit 107 to the base station 3.

The first interference measuring unit 105 measures the interference power in the non-transmission section for a specified period immediately before or immediately after receiving the radio packet which is the received signal signal processed by the modulation / demodulation processing unit 103. The first interference measuring unit 105 outputs the first interference power measurement result, which is the measurement result of the interference power, to the selection unit 107.

The second interference measuring unit 106 measures the interference power with a null symbol in the OFDM (Orthogonal Frequency Division Multiplexing) symbol included in the data unit of the radio packet which is the received signal signal processed by the modulation / demodulation processing unit 103. The null symbol is a symbol in which no signal is superimposed, which is distributed in the data part in the radio packet. The second interference measurement unit 106 outputs the second interference power measurement result, which is the measurement result of the interference power, to the selection unit 107.

The selection unit 107 selects the interference power measurement results measured by the first interference measurement unit 105 and the second interference measurement unit 106. Specifically, the selection unit 107 selects and outputs at least one of the first interference power measurement result and the second interference power measurement result based on the distance between the base station 3 and the mobile station 1. ..

Next, the operation of the wireless communication system 10 will be described. In FIG. 1, the car 2 moves up and down in the hoistway 4. For example, when the destination button on the top floor is pressed in the car 2 on the bottom floor, the destination information is wirelessly transmitted to the base station 3 via the mobile station 1. The base station 3 transmits the received destination information to the elevator control panel in the machine room. The elevator control panel drives the hoist according to the destination information and moves the car 2 to the top floor. When the car 2 reaches the top floor, the elevator control panel stops the hoisting machine and transmits instruction information for opening the door of the car 2, that is, a door opening instruction to the base station 3. The base station 3 wirelessly transmits a door opening instruction to the mobile station 1. The mobile station 1 transmits the door opening instruction to the control device of the car 2. The control device of the car 2 opens the door of the car 2 according to the door opening instruction. The position information of the car 2 is grasped by the driving amount of the hoisting machine in the elevator control panel, and the car 2 recognizes the precise position information of the hoistway 4, and the elevator passes through the mobile station 1 and the base station 3. It is transmitted to the control panel.

FIG. 3 is a diagram showing a state of wireless transmission between the base station 3 and the mobile station 1 according to the present embodiment. In FIG. 3, the horizontal axis represents time and the vertical axis represents frequency channels. In the present embodiment, the base station 3 and the mobile station 1 perform wireless transmission while performing frequency hopping while performing wireless transmission by TDD (Time Division Duplex). Specifically, the base station 3 and the mobile station 1 transmit and receive wireless packets while switching frequency channels in a time unit called a slot to perform downlink communication from the base station 3 to the mobile station 1 and to the mobile station 1. Uplink communication from the mobile station 1 to the base station 3 is performed. In the wireless communication system 10, the hopping sequence is set so that different frequency channels are used at the same time between each combination of the base station 3 and the mobile station 1 that perform wireless communication in each hoistway 4, that is, between the hoistways 4. It is determined, and it is assumed that mutual communication between the hoistways 4 is prevented from interfering with each other. Time synchronization between the hoistways 4 is performed, for example, via the wired network 5.

FIG. 4 is a diagram showing an example of radio packets transmitted / received between the base station 3 and the mobile station 1 according to the present embodiment. The wireless packet shown in FIG. 4 is a wireless packet transmitted in each slot shown in FIG. 3, and is composed of a preamble unit 41 and a data unit 42. The preamble unit 41 is a section in which a known signal is transmitted. The wireless communication device on the receiving side synchronizes the frequency and time by the reception processing of the preamble unit 41, and thereafter performs the reception processing of the data unit 42 according to the synchronization information. The data unit 42 is an area in which net information to be transmitted is stored. The data unit 42 is, for example, a signal modulated by OFDM.

FIG. 5 is a diagram showing an example of a data unit 42 included in a radio packet transmitted / received between the base station 3 and the mobile station 1 according to the present embodiment. In FIG. 5, the horizontal axis represents time, that is, the OFDM symbol, and the vertical axis represents frequency, that is, subcarriers. Null symbols are distributed in a distributed manner with respect to the data symbols mapped in OFDM. The null symbol is a symbol on which no signal is superimposed in the wireless communication device on the transmitting side.

In the mobile station 1, the RF unit 102 converts the radio wave received by the antenna 101 into a baseband digital signal. After that, according to the control from the transmission / reception control unit 104, the modulation / demodulation processing unit 103 performs signal processing such as demodulation and decoding on the baseband digital signal converted by the RF unit 102. The first interference measuring unit 105 measures the received power in a specified measurement period while sliding the measurement target time with respect to the signal processed by the modulation / demodulation processing unit 103, that is, the wireless packet. The measurement period is assumed to be, for example, one tenth to one hundredth of the length of the wireless packet. If the measurement period is too long, the measurement accuracy will be high, but the transmission band will be wasted.

The modulation / demodulation processing unit 103 detects the preamble unit 41 of the wireless packet and estimates timing information, frequency deviation information, and the like. Based on the timing information estimated by the modulation / demodulation processing unit 103, the transmission / reception control unit 104 causes interference power with respect to the first interference measurement unit 105 in the first interference measurement area 43 immediately before the wireless packet shown in FIG. Is instructed to output the measured interference power measurement result to the selection unit 107. When the signal processing for the preamble unit 41 is completed, the modulation / demodulation processing unit 103 shifts to the demodulation processing of the data unit 42. The modulation / demodulation processing unit 103 performs frequency conversion for each OFDM symbol on the data unit 42, outputs the power of each null symbol to the second interference measurement unit 106, and outputs each data symbol from the null symbol around each data symbol. Calculate the average value of the interference power corresponding to. The interfering power corresponding to each data symbol is used to calculate the reliability of the data symbol. For example, the modulation / demodulation processing unit 103 performs error correction processing by increasing the reliability, that is, the likelihood, for a data symbol having a large interference power, and increasing the reliability, that is, the likelihood, for a data symbol having a small interference power. As a result, the modulation / demodulation processing unit 103 can realize highly reliable wireless communication even in a radio wave environment where there is a lot of interference.

By arranging the null symbol, the amount of information that can be transmitted is reduced by the amount of the null symbol, but if the transmission power is constant, the power amount of the null symbol can be added to the data symbol. be. In a wireless system in which the transmission rate is sufficiently secured and the coding rate is low to some extent, that is, the redundancy is high, the increase in the coding rate is offset by the increase in the signal power.

The second interference measurement unit 106 averages the power of the null symbol output from the modulation / demodulation processing unit 103, that is, the power measured in the second interference measurement area 44 shown in FIG. 5 over the entire wireless packet. And output to the selection unit 107 as the second interference power measurement result.

FIG. 6 is a diagram showing leakage from an adjacent subcarrier in power measurement with a null symbol according to the present embodiment. FIG. 6 shows an example in which the interference power is measured by the subcarrier of the null symbol sandwiched between the two data symbols. In the measurement of interference power, due to quantization noise, etc., leakage from adjacent subcarriers actually enters at a level about 30 dB lower than the level of the data subcarrier, which is higher than leakage from adjacent subcarriers. There is a problem that small interference power cannot be measured. That is, when the signal level of the desired wave is small, that is, when the base station 3 and the mobile station 1 are separated from each other, it is possible to measure a low level interference wave. On the other hand, when the signal level of the desired wave is large, that is, when the base station 3 and the mobile station 1 are close to each other, it becomes difficult to measure a low level interference wave.

Based on the above, when the distance between the mobile station 1 and the base station 3 is short, the selection unit 107 selects the interference power measurement result measured by the first interference measurement unit 105, and the mobile station 1 and the base station When the distance from 3 is long, the interference power measurement result measured by the second interference measurement unit 106 is selected. As a result, the selection unit 107 has a high-precision interference power measurement result measured for the entire wireless packet at a position where the distance between the base station 3 and the mobile station 1 is long and the signal power is small and therefore the influence of the interference wave is large. Can be obtained. Further, the selection unit 107 obtains an interference power measurement result having a short measurement period but a wide dynamic range at a position where the distance between the base station 3 and the mobile station 1 is short and the signal power is large and therefore the influence of the interference wave is small. be able to. When the signal level of the desired wave is high, the low level interference wave basically has little effect on communication, but the received power may temporarily decrease due to instantaneous value fluctuations, shadow wings, etc., and it reaches a low level. It is important that the interference power can be measured. The selection unit 107 can determine whether the distance between the mobile station 1 and the base station 3 is close or far, for example, by using a threshold value for determining the distance between the mobile station 1 and the base station 3. Is.

The selection unit 107 outputs the selected interference power measurement result to the transmission / reception control unit 104. The transmission / reception control unit 104 controls to wirelessly transmit the interference power measurement result acquired from the selection unit 107 to the base station 3 together with other control information. The base station 3 outputs the received interference power measurement result to the radio wave environment monitoring device 6 together with the position information at the time of measurement, the frequency channel information at the time of measurement, and the like. The base station 3 may receive the position information at the time of measurement from the system side that controls the elevator such as the elevator control panel, or may estimate it from the reception level of the desired wave.

The radio wave environment monitoring device 6 accumulates the acquired interference power measurement results while averaging them according to the position information at the time of measurement and the frequency channel information at the time of measurement. FIG. 7 is a diagram showing an example of the interference power measurement result stored in the radio wave environment monitoring device 6 according to the present embodiment. FIG. 7 shows a state in which the radio wave environment monitoring device 6 maps and accumulates the interference power measurement result corresponding to the position of the car 2 at the time of measurement and the frequency channel at the time of measurement. The radio wave environment monitoring device 6 issues a warning when the interference power exceeds a certain threshold value by observing aging, and sets the transmission rate, the number of continuous transmissions, etc. according to the interference power of the frequency channel used for transmission. Change it. As a result, the radio wave environment monitoring device 6 can operate the wireless communication system 10 more stably.

In the present embodiment, the radio wave environment monitoring device 6 uses the accumulated information as the amount of interference, that is, the interference power, but in combination with the reception power of the desired wave, the signal power to the interference power ratio is SIR (Signal-). The to-interference ratio) may be calculated and accumulated. In this case, the radio wave environment monitoring device 6 can be evaluated more in line with the communication quality.

Further, although the first interference measuring unit 105 measures the interference power in the non-transmission section immediately before receiving the radio packet, the interference power may be measured in the non-transmission section immediately after receiving the radio packet. good. As shown in FIG. 3, the radio packet length is short with respect to the slot length, and there is a margin before and after the radio packet with respect to the slot. Therefore, the first interference measuring unit 105 can also measure the interference power in the non-transmission section immediately after receiving the wireless packet. The non-transmission section immediately after receiving the wireless packet is specifically the area on the right side of the data unit 42 of the wireless packet shown in FIG.

Further, the selection unit 107 switches between the interference power measurement result of the first interference measurement unit 105 and the interference power measurement result of the second interference measurement unit 106 according to the position of the car 2, but the present invention is not limited to this. .. The selection unit 107 may always use the interference power measurement result of the first interference measurement unit 105, and may combine the interference power measurement result of the second interference measurement unit 106 when the position of the car 2 is far. Further, in the wireless communication system 10, the function of the selection unit 107 may be provided to the base station 3, the radio wave environment monitoring device 6, and the like.

Although the case where the mobile station 1 measures the interference power has been described in the present embodiment, the base station 3 can also measure the interference power in the same manner. The base station 3 collects only the interference power measurement result when the car 2 is in a distant position, or in addition to the interference power measurement result of the first interference measurement unit 105, only when the car 2 is in a distant position. The interference power measurement result of the interference measurement unit 106 of 2 may be extracted.

The wireless communication system 10 is a first wireless communication device as in the present embodiment when the first wireless communication device measures the interference power and transmits the interference power measurement result to the second wireless communication device. May be the mobile station 1 and the second wireless communication device may be the base station 3. Contrary to the present embodiment, the first wireless communication device is the base station 3 and the second wireless communication device is moved. It may be station 1.

The operation of mobile station 1 will be explained using a flowchart. FIG. 8 is a flowchart showing the operation of the mobile station 1 according to the present embodiment. In the mobile station 1, the RF unit 102 converts the radio packet received by the antenna 101 into a baseband digital signal (step S1). The modulation / demodulation processing unit 103 performs signal processing such as demodulation and decoding of the wireless packet (step S2).

The first interference measurement unit 105 measures the interference power of the wireless packet in the first interference measurement area 43 (step S3). The first interference measuring unit 105 outputs the first interference power measurement result, which is the result of measuring the interference power, to the selection unit 107. The second interference measurement unit 106 measures the interference power of the wireless packet in the second interference measurement area 44 (step S4). The second interference measuring unit 106 outputs the second interference power measurement result, which is the result of measuring the interference power, to the selection unit 107. As described above, since the base station 3 and the mobile station 1 perform wireless transmission while performing frequency hopping while performing wireless transmission by TDD, the first interference measuring unit 105 and the second interference measuring unit 105 and the second The interference measuring unit 106 measures the interference power for each frequency channel.

The selection unit 107 selects at least one of the first interference power measurement result and the second interference power measurement result based on the position of the car 2, that is, the distance between the base station 3 and the mobile station 1 (step). S5). Specifically, the selection unit 107 selects the first interference power measurement result when the distance between the base station 3 and the mobile station 1 is less than the threshold value, and the distance between the base station 3 and the mobile station 1 is equal to or larger than the threshold value. In the case of, the second interference power measurement result is selected. Alternatively, the selection unit 107 selects the first interference power measurement result when the distance between the base station 3 and the mobile station 1 is less than the threshold value, and when the distance between the base station 3 and the mobile station 1 is greater than or equal to the threshold value, the selection unit 107 selects the first interference power measurement result. The first interference power measurement result and the second interference power measurement result are selected. The selection unit 107 outputs the selected interference power measurement result to the transmission / reception control unit 104. As described above, the threshold value is for determining whether the distance between the base station 3 and the mobile station 1 is short or long. That is, when the distance between the base station 3 and the mobile station 1 is less than the threshold value, it means that the distance between the base station 3 and the mobile station 1 is short, and the distance between the base station 3 and the mobile station 1 is equal to or larger than the threshold value. The case of means that the distance between the base station 3 and the mobile station 1 is long.

Next, the hardware configuration of the mobile station 1 and the base station 3 will be described. As described above, since the mobile station 1 and the base station 3 have the same configuration, the mobile station 1 will be described as an example. In the mobile station 1, the antenna 101 is an antenna element. The RF unit 102 is an analog circuit, an analog digital converter, a digital analog converter, or the like that performs frequency conversion or the like. The modulation / demodulation processing unit 103, the transmission / reception control unit 104, the first interference measurement unit 105, the second interference measurement unit 106, and the selection unit 107 are realized by a processing circuit. The processing circuit may be a processor and memory for executing a program stored in the memory, or may be dedicated hardware. The processing circuit is also called a control circuit.

FIG. 9 is a diagram showing a configuration example of the processing circuit 90 when the processing circuit included in the mobile station 1 according to the present embodiment is realized by a processor and a memory. The processing circuit 90 shown in FIG. 9 is a control circuit and includes a processor 91 and a memory 92. When the processing circuit 90 is composed of the processor 91 and the memory 92, each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 92. In the processing circuit 90, each function is realized by the processor 91 reading and executing the program stored in the memory 92. That is, the processing circuit 90 includes a memory 92 for storing a program in which the processing of the mobile station 1 is eventually executed. It can be said that this program is a program for causing the mobile station 1 to execute each function realized by the processing circuit 90. This program may be provided by a storage medium in which the program is stored, or may be provided by other means such as a communication medium.

In the above program, the first interference measuring unit 105 measures the interference power in the non-transmission section for a specified period immediately before or immediately after receiving the wireless packet, and outputs the first interference power measurement result. The first step, the second step 106 in which the second interference measuring unit 106 measures the interference power with the null symbols distributed in the wireless packet, and the second step and the selection unit 107 output the second interference power measurement result. , A third step of selecting and outputting at least one of the first interference power measurement result or the second interference power measurement result based on the distance between the second wireless communication device and the wireless communication device. It can be said that this is a program that causes the mobile station 1 to execute the above.

Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic unit, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), or the like. The memory 92 is, for example, non-volatile or volatile such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (registered trademark) (Electrically EPROM). This includes semiconductor memory, magnetic disks, flexible disks, optical disks, compact disks, mini disks, DVDs (Digital Versatile Disc), and the like.

FIG. 10 is a diagram showing an example of a processing circuit 93 when the processing circuit included in the mobile station 1 according to the present embodiment is configured by dedicated hardware. The processing circuit 93 shown in FIG. 10 is, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The thing is applicable. As for the processing circuit, a part may be realized by dedicated hardware and a part may be realized by software or firmware. As described above, the processing circuit can realize each of the above-mentioned functions by the dedicated hardware, software, firmware, or a combination thereof.

As described above, according to the present embodiment, in the wireless communication system 10, the mobile station 1 measures the interference power in the non-transmission section immediately before the reception of the wireless packet and the null symbol in the wireless packet, and the base station. It was decided to select as the interference power measurement result according to the distance between 3 and the mobile station 1. As a result, the mobile station 1 can obtain the interference power measurement result having a wide dynamic range regardless of the position of the car 2 while suppressing the dedicated time for measuring the interference power and maintaining the transmission efficiency. Is. The mobile station 1 can acquire a highly accurate interference power measurement result with a large number of measurement samples especially at a position where the power of the desired wave is small and the influence of the interference power is large. It becomes possible to realize a stable wireless communication system 10. In this way, the mobile station 1 can improve the measurement accuracy of the radio wave environment while suppressing the use of time and frequency for measuring the radio wave environment.

The configuration shown in the above embodiments is an example, and can be combined with another known technique, can be combined with each other, and does not deviate from the gist. It is also possible to omit or change a part of the configuration.

1,1a, 1b, 1c mobile station, 2a, 2b, 2c basket, 3a, 3b, 3c base station, 4a, 4b, 4c hoistway, 5 wired network, 6 radio environment monitoring device, 10 wireless communication system, 41 preamble Unit, 42 data unit, 43 first interference measurement area, 44 second interference measurement area, 101 antenna, 102 RF unit, 103 modulation / demodulation processing unit, 104 transmission / reception control unit, 105 first interference measurement unit, 106 second Interference measurement unit, 107 selection unit.

Claims

A wireless communication device which is the first wireless communication device in a wireless communication system in which a first wireless communication device and a second wireless communication device perform wireless communication while changing the distance.
A first interference measuring unit that measures interference power in a non-transmission section for a specified period immediately before or immediately after receiving a radio packet and outputs a first interference power measurement result, and a first interference measuring unit.
A second interference measuring unit that measures the interference power with the null symbols distributed in the radio packet and outputs the second interference power measurement result, and the second interference measuring unit.
With a selection unit that selects and outputs at least one of the first interference power measurement result or the second interference power measurement result based on the distance between the second wireless communication device and the wireless communication device. ,
A wireless communication device characterized by comprising.
The selection unit selects the first interference power measurement result when the distance is less than the threshold value, and selects the second interference power measurement result when the distance is greater than or equal to the threshold value.
The wireless communication device according to claim 1.
When the distance is less than the threshold value, the selection unit selects the first interference power measurement result, and when the distance is equal to or more than the threshold value, the first interference power measurement result and the second interference power measurement result. Select the result,
The wireless communication device according to claim 1.
Communicate with the second wireless communication device while performing frequency hopping.
The first interference measuring unit and the second interference measuring unit measure the interference power for each frequency channel.
The wireless communication device according to any one of claims 1 to 3, wherein the wireless communication device is characterized.
The first wireless communication device, which is the wireless communication device according to any one of claims 1 to 4,
The second wireless communication device and
With
A wireless communication system characterized in that the first wireless communication device and the second wireless communication device perform wireless communication while changing the distance.
A control circuit for controlling a wireless communication device, which is the first wireless communication device in a wireless communication system in which a first wireless communication device and a second wireless communication device perform wireless communication while changing the distance. ,
The interference power is measured in the non-transmission section for a specified period immediately before or immediately after receiving the wireless packet, and the first interference power measurement result is output.
The interference power is measured by the null symbols distributed in the radio packet, and the second interference power measurement result is output.
Based on the distance to the second wireless communication device, at least one of the first interference power measurement result or the second interference power measurement result is selected and output.
A control circuit characterized by having a wireless communication device carry out the above.
A storage that stores a program for controlling a wireless communication device which is the first wireless communication device in a wireless communication system in which a first wireless communication device and a second wireless communication device perform wireless communication while changing the distance. It ’s a medium,
The program
The interference power is measured in the non-transmission section for a specified period immediately before or immediately after receiving the wireless packet, and the first interference power measurement result is output.
The interference power is measured by the null symbols distributed in the radio packet, and the second interference power measurement result is output.
Based on the distance to the second wireless communication device, at least one of the first interference power measurement result or the second interference power measurement result is selected and output.
A storage medium characterized by having a wireless communication device carry out the above.
A radio wave monitoring method for a wireless communication device, which is the first wireless communication device in a wireless communication system in which a first wireless communication device and a second wireless communication device perform wireless communication while changing the distance.
The first step, in which the first interference measuring unit measures the interference power in the non-transmission section for a specified period immediately before or immediately after receiving the radio packet and outputs the first interference power measurement result,
The second step, in which the second interference measuring unit measures the interference power with the null symbols distributed in the radio packet and outputs the second interference power measurement result,
The selection unit selects and outputs at least one of the first interference power measurement result and the second interference power measurement result based on the distance between the second wireless communication device and the wireless communication device. The third step to do and
A radio wave monitoring method characterized by including.