JP2000193697A - Measuring system of reception electric field strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically measure reception electric field strength, while always monitoring and moreover ensuring a transmission line in a radio communication system without stopping an existing system. SOLUTION: Data collected in each sub-station are transmitted to a main station by carrying out radio communication by a polling system through a stationary radio network from the main station 100 to a plurality of sub-stations 300 via a plurality of radio relay stations 200. When the main station 100 transmits a station selection call signal to sub-stations 300 by the polling system, after the radio relay station detects the station selection call signal radio- relayed, the data radio signal from the sub-stations 300 is received by a radio transmitter/receiver 43. A reception electric field strength during the reception of the data radio signal is detected by an electric field strength detection part 23 and the detected data of the reception electric field strength are transmitted to the parent station 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for measuring a received electric field strength applied to a telemeter system such as gas, electricity and water, or a radio communication system such as a telecontrol system.

[0002]

2. Description of the Related Art For example, as a main data communication system in a gas supply system, the following communication systems are in practical use. (A) Monitoring and control system for gas supply adjustment: Used for monitoring and control for the purpose of stable supply and adjustment of gas such as gas pressure and flow rate at gas production, pipelines, supply bases, and the like. (B) Disaster prevention control system: information on the determination of the suspension of gas supply from a gas supply base or the like in the event of a disaster (seismic intensity, pressure,
Flow rate) and for gas supply cutoff control. Here, the data communication medium is constituted by a fixed wireless line using a radio frequency for gas.

[0003] Most of the conventional wireless systems as a data communication medium in a gas supply system are implemented by a multiplex wireless system, and a data collection system is always implemented by a transmission system. Due to recent changes in the wireless environment (such as an increase in demand for mobile communications such as mobile phones), the need for frequency shift has arisen from the viewpoint of effective use of radio frequencies.
The transition to the single wireless system was started sequentially. Along with this, the data collection method of the station to be changed to the single wireless method has been implemented by the "polling method".

[0004]

As to the measurement and monitoring of the received electric field strength in such a wireless communication system, the continuous transmission method by multiplex radio has conventionally been employed, so that continuous monitoring (including a decrease in the threshold value) is performed for each station. ) Could be implemented, but after the change of the wireless system, it became difficult to measure and monitor the received electric field strength for each station because of the single wireless polling system.
It became correspondence in daily inspection. That is, the wireless data collection system that collects data by a polling method between a master station and a plurality of slave stations to be collected via a wireless line is temporarily stopped, and any data for which the reception electric field strength needs to be measured is determined. A test radio wave is fired from the collection target slave station,
The measurement was performed at the master station using an electric field strength measuring instrument.

Therefore, the radio data collection system is continuously stopped when the change of the received electric field strength value at the master station of the arbitrary slave station for data collection is continuously measured on a daily or monthly basis. Because of the necessity to do so, there is a problem in the actual operation and it is not practical. In addition, when performing without stopping the wireless data collection system, there is a method of configuring a pseudo measurement environment of the wireless data collection system by using radio waves having different radio frequencies, but as a result, it is necessary to treat it as an approximate value. Become. In the above two methods,
In any case, since radio interference or the like occurs between the master station and the data collection target slave station, there is a problem in that it often takes considerable time to investigate the cause and take countermeasures.

On the other hand, based on the lessons learned from the Great Hanshin-Awaji Earthquake, the number of data collection bases for disaster prevention has been increased from several tens at the time to about 400 as earthquake countermeasures. I have. In addition, the necessity of measuring and managing the reception electric field strength is essential to ensure that the gas supply / adjustment and disaster prevention measures can be performed reliably and promptly in any case. Further, since the number of stations has become enormous, the necessity of automation has been increased in order to keep the radio wave propagation management of the data collection station as usual. Also,
Location conditions for monitoring / control bases (slave stations) include residential areas,
There are many stations in the city center, etc.
Buildings and the like may be lined up and a failure in radio wave propagation may occur. Therefore, after a failure occurs, it takes a very long time to take countermeasures and recovery, which is not desirable for security.Therefore, it is necessary to monitor the radio wave propagation status continuously to detect the failure situation in advance and take countermeasures. There is.

An object of the present invention is to solve the above problems and constantly monitor and secure a propagation path in a wireless communication system.
Moreover, it is an object of the present invention to provide a receiving electric field intensity measuring system capable of automatically measuring the receiving electric field intensity without stopping the working system.

[0008]

According to a first aspect of the present invention, there is provided a radio communication system for performing communication between a master station and a plurality of slave stations via a fixed radio line. When the master station transmits a station selection calling signal to each slave station in a polling method, after detecting the station selection calling signal, the master station receives a data signal from the slave station, and receives a received signal strength during reception of the data signal. Measuring means for measuring the temperature.

In a second aspect of the present invention, the measuring means detects a station selection calling signal and then transmits a data signal from a slave station. When the preamble signal is received, the measurement of the reception electric field strength during reception of the data signal is started.

Further, in the receiving electric field strength measuring system according to a third aspect of the present invention, in the receiving electric field strength measuring system according to the second aspect, the measuring means is configured to receive a predetermined signal during reception of a data signal received after the preamble signal. The reception electric field strength is measured a plurality of times.

According to a fourth aspect of the present invention, in the receiving electric field strength measuring system according to the third aspect, the measuring means compresses the data of the receiving electric field intensity measured a plurality of times. It is characterized by.

Further, in the receiving electric field strength measuring system according to the fifth aspect, in the receiving electric field strength measuring system according to the fourth aspect, compressing the data of the receiving electric field intensity measured a plurality of times is performed by a plurality of times. The method is characterized by at least one of calculating an average value of the data, calculating a maximum value of the data a plurality of times, and calculating a minimum value of the data a plurality of times.

According to a sixth aspect of the present invention, in the receiving electric field strength measuring system according to the first or second aspect, the measuring means detects a station selection calling signal and then receives the signal from the slave station. When the preamble signal of the data signals is not received, measurement of the reception field strength during reception of the data signal is started a predetermined time after the detection of the station selection calling signal.

According to a seventh aspect of the present invention, in the receiving electric field strength measuring system according to any one of the first to sixth aspects, the wireless communication system includes at least one wireless station from a master station. The wireless relay station communicates with a plurality of slave stations via a fixed wireless line via a relay station, and the wireless relay station is configured to compress the received electric field strength measured by the measuring means and the received electric field strength or the data thereof. Transmission means for transmitting the data to the master station.

Further, in the receiving electric field strength measuring system according to the present invention, in the receiving electric field strength measuring system according to any one of the first to seventh aspects, the wireless communication system is collected by each slave station. It is characterized by being at least one of a telemeter system for transmitting data to a master station and a telecontrol system for controlling each slave station from the master station.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a telemeter radio communication system according to one embodiment of the present invention. In the telemeter radio communication system of this embodiment, a plurality of radio relay stations 200-1 to 200-M (collectively, 200
Is assigned. ), A plurality of slave stations 300-1 to 300- located within the coverage of each wireless relay station 200.
N, 310-1 to 310-N '(collectively denoted by the reference numeral 300), wireless communication is performed by a polling method via a fixed wireless line, and collected by each slave station. This is a telemeter system that transmits data (for example, billing data and process data of consumer goods such as gas, electricity, and water) to a master station.

Here, the telemeter radio communication system is as follows:
The radio relay station 200 includes an electric field intensity detection unit 23 that detects an electric field intensity of a data radio signal from the slave station 300 while receiving the data radio signal, and a relay controller 20 that controls an operation of the electric field intensity detection unit 23. The relay station 200 detects a wirelessly relayed station selection call signal when the master station 100 transmits a station selection call signal to each of the slave stations 300 in a polling manner, and then transmits a data radio signal from the slave station 300. Is received by the wireless transmitter / receiver 43, the received electric field intensity during the reception of the data radio signal is detected by the electric field intensity detecting section 23, and the data of the detected received electric field intensity is transmitted to the master station 100.

In FIG. 1, the master station 100 (a) transmits a station selection signal to each slave station 300 via the radio relay station 200 by a polling method, and in response to this, the slave station 3
(B) a telemeter master station device 1 that collects data from the 00 telemeter slave station device 32 and performs predetermined data processing;
Controlled by the master station controller 10, the data signal output from the telemeter master station device 1 is modulated by a data modulation method such as MSK, and the modulated signal is output to the radio transceiver 3 while being received by the radio transceiver 3. A data modem 2 that demodulates the obtained radio signal into a data signal and outputs the data signal to the telemeter master station device 1 and the master station controller 10;
(C) The transmission unit of the wireless transceiver 3 is activated based on a predetermined activation signal from the telemeter master station device 1 (although the power is always on, the transmission unit is switched from the sleep mode in response to the activation signal). In order to set the operation mode, a transmission operation current is supplied to the transmission unit.) The master station stores the data signal demodulated by the data modem 2 in the memory 11 and outputs the data signal to the monitoring control device 400. Controller 1
0, and (d) each of the radio relay stations 200 having the antenna 3a.
-1 to 200-M and a wireless transceiver 3 for performing bidirectional wireless communication via a fixed wireless line using data wireless signals. Here, the master station 100 and each wireless relay station 200-
The wireless communication between the wireless relay stations 200 through 1 through 200-M is performed at different times for each wireless relay station 200.

The monitoring control device 400 performs input and output of an instruction command and data, for example, a data input device 401 such as a keyboard and a mouse, and displays or prints collected data to be monitored and controlled and data of a received electric field intensity. And a data output device 402 such as a CRT display or a printer for receiving data of the received electric field strength measured by the wireless relay station 200, which is output from the master station controller 10, and in a predetermined cycle. When the signal cannot be received periodically, the data is treated as missing data, and based on the received electric field strength data, a radio propagation path failure occurs when the data is less than a predetermined threshold compared to a predetermined threshold. And outputs the received electric field strength and the determination result to the data output device 402 to notify the operator.

Each radio relay station 200 has (a) an antenna 4
1a, a wireless transceiver 41 for performing bidirectional wireless communication using a data wireless signal with the master station 100 via a fixed wireless line, and (b) controlled by the relay controller 20 and received by the wireless transceiver 41. The demodulated data radio signal is demodulated and output to the relay controller 20, and the demodulated data signal is modulated by a predetermined data modulation method such as MSK to output a modulated signal to the radio transceiver 43. A data modem 42 for demodulating the data radio signal received at 43, modulating the demodulated data signal with a predetermined data modulation method such as MSK, and outputting the modulated signal to the radio transceiver 41; (D) a wireless transceiver 43 comprising a wireless communication device 43a for performing bidirectional wireless communication with each slave station 300 using a data wireless signal via a fixed wireless line; Been (specifically, signal converted into an intermediate frequency signal by the frequency converting unit in the wireless transceiver 43) data radio signal received by the line transceiver 43 based on,
The master station 100 includes a field strength detector 23 for detecting and measuring the received field strength and outputting the detected field strength to the relay controller 20; (e) a memory 21 for storing data; and a timer 22 for timing the timing for measuring the received field strength. Activates the transmission units of the wireless transceivers 41 and 43 based on the press control ON signal from (the power is always on, but sets the transmission unit from the sleep mode to the operation mode based on the press control ON signal) After transmitting the transmission operation current to the transmission unit, the data of the received electric field intensity detected and measured by the electric field intensity detection unit 23 based on the time value of the timer 22 is stored in the memory 21. After performing a predetermined data process described in detail later, a data signal for reporting to the master station 100 is generated, and the data signal is generated via the data modem 42 and the wireless transceiver 41. And transmits to the station 100 and a relay controller 20.

Here, the radio relay station 200 and each slave station 30
Between 0, wireless communication is performed using a polling method.
For example, the radio relay station 200-1 transmits the coverage A
In charge of the slave stations 300-1 to 300-N located in the district, wireless communication is performed with the slave stations 300-1 to 300-N by using a polling method. Also, the radio relay station 200-M is in charge of the slave stations 310-1 to 310-N 'located in the area B of the coverage, and
Wireless communication is performed using a polling method with the communication terminals 10-1 to 310-N '.

Each slave station 300 (a) includes an antenna 31a, performs bidirectional wireless communication with the wireless relay station 200 using a data wireless signal via a fixed wireless line, and further includes a data modem (not shown). ), A received data radio signal is demodulated into a data signal, and the demodulated data signal is output to the telemeter slave station device 32. The data signal from the telemeter slave station device 32 is modulated and a modulated signal is transmitted. Device 31 and (b) a memory 33,
From the memory 33, in particular in response to its own station selection signal contained in the data signal.
And a telemeter slave station device 32 for outputting predetermined data stored in the wireless transceiver 31 to the wireless transceiver 31 in the form of a data signal. Here, the wireless transceiver 31 activates the transmission unit of the wireless transceiver 31 in response to the own station selection calling signal from the master station 100 (although the power is always on, the own station selection calling is performed). A transmission operation current is supplied to the transmission unit in order to set the transmission unit from the sleep mode to the operation mode based on the signal.)

FIG. 2 is a timing chart showing the operation of the telemeter radio communication system of FIG.

First, the master station 100 designates and switches the wireless relay station 200 at time t11, and then switches the wireless relay station 200.
00, the wireless transceiver 41 in the wireless relay station 200,
A press control ON signal (500 milliseconds) is transmitted to make the transmission unit 43 operate. About 29 from time t11
At time t12 0 ms later, master station 100 transmits dummy data (20 ms) as a preamble signal to each slave station 300 via wireless relay station 200, and then specifies at time t13. The station selection calling signal for the slave station is transmitted twice (170 milliseconds). From time t14 when the two consecutive transmissions of the station selection calling signal are completed, each slave station 300 demodulates the received data radio signal and determines whether or not the signal is its own station selection calling signal (100 milliseconds). The slave station 300 that has determined that it is its own station selection calling signal is the wireless transceiver 31 in its own station.
And sends the press control ON signal to the transmitting unit to set the transmitting unit in the operation mode. After about 380 milliseconds from the time t14, the dummy data as the preamble signal is transmitted to the master station 100 via the radio relay station 200, and then the telemeter Slave station device 3
Telemeter 15 measured in 2 and stored in memory 33
The data of the item is transmitted in the form of a data signal to the radio relay station 200.
To the parent station 100 via In response to this, the radio relay station 200 sets about 20 milliseconds after time t15,
Since the reception electric field strength of the wireless data signal from the slave station 300 is in a stable state, the wireless data signal of 15 items of the telemeter is received and relayed from the time t16 to 380 milliseconds and transmitted to the master station 100. I do.

Here, while the slave station 300 is transmitting the wireless data signal of 15 telemeters from time t16 to time t17, the received electric field strength of the wireless data signal is stable. The electric field intensity detector 23 measures the received electric field intensity four times every 100 milliseconds from t16, and outputs the data to the relay controller 20.

The above description with reference to FIG.
, Through the wireless relay station 200, performs a process of selecting one slave station 300 by a polling method. This process is repeated for a plurality of slave stations 300.

FIG. 3 is a flowchart showing the electric field strength measurement processing executed by the relay controller 20 of FIG. In FIG. 3, first, in step S1, the parent station 10
It is determined whether a station selection calling signal for the designated slave station 300 from 0 has been received and identified, and the processing of step S1 is repeated until identification is performed.
1 is YES), and the count value T of the timer 22 is determined in step S2.
Is reset to 0 (corresponding to time t14 in FIG. 2). Then, in step S3, it is determined whether or not dummy data as a preamble signal from the slave station 300 has been received. If YES, the process proceeds to step S5, while if NO, the timer 22 counts in step S4. It is determined whether the value T has become 400 milliseconds or more.
When YES is determined in the step S4, it is determined that the reception and the detection of the dummy data have failed, and the process proceeds to a step S5. On the other hand, if NO in step S4, the process returns to step S3 and the above processing is repeated.

Next, in step S5, as shown in FIG. 2, while the radio field signal of the 15 items of the telemeter is being received from the slave station 300 by the The data is detected four times every time, and the detected data of the received electric field strength is temporarily stored in the memory 2.
1 is stored. Further, in step S6, the memory 21
(A) calculating an average value of a plurality of times of data, (b) calculating a maximum value of a plurality of times of data, c) performing compression processing on the received electric field strength data by performing at least one of the calculation of the minimum value of the data a plurality of times. Further, a data transmission process is executed in step S7, that is, the data of the received electric field strength that has been subjected to the compression process is transmitted to the master station 100 via the data modem 42 and the wireless transceiver 41 in the wireless relay station 200. The control flow waits for a station selection call signal for the next slave station 300 in step S1.

Monitoring and control device 40 provided in master station 100
0, for each slave station 300, that is, for the radio relay station 200
For each fixed wireless line between the mobile station 300 and each of the slave stations 300, receives the data of the received electric field strength measured by the radio relay station 200, and sets a predetermined threshold value based on the received data of the received electric field strength. When it is less than the threshold value, it is determined that a radio propagation path failure has occurred, and the received electric field strength and the result of the determination are output to the data output device 402 to notify the operator. Therefore, when a radio propagation path failure occurs, it is possible to respond quickly.

As described above, according to the present embodiment, wireless communication is performed between the master station 100 and the plurality of slave stations 300 via the plurality of wireless relay stations 200 by the polling method via the fixed wireless lines. In a telemetry wireless communication system that performs communication and transmits data collected by each slave station to a master station, the wireless relay station 200 transmits a station selection call signal to the slave station 300 by the master station 100 in a polling manner. When transmitting, after detecting a station selection calling signal to be wirelessly relayed, a data radio signal from the slave station 300 is transmitted to the radio transceiver 4.
3, the received electric field intensity is detected by the electric field intensity detection unit 23 during reception of the data radio signal, and the data of the detected received electric field intensity is transmitted to the master station 100. Therefore, while receiving the data in the telemeter system, it is possible to measure the received electric field strength by receiving the radio wave from each slave station 300, so that the reception is automatically performed without interrupting the working line as in the conventional example. The electric field strength can be measured, and the propagation path in the wireless communication system can be constantly monitored and reliably secured. If an abnormality occurs in the wireless propagation path, it is possible to respond quickly.

<Modification> In the above embodiments, the telemeter radio communication system has been described. However, the present invention is not limited to this, and a telemeter system for transmitting data collected by each slave station to a master station is provided. And / or a telecontrol system for controlling each slave station from the master station.

In the above embodiment, the radio relay station 20
0, the received electric field strength of the data radio signal from each slave station 300 is detected by the electric field strength detection unit 23. However, the present invention is not limited to this. May be detected by another electric field intensity detection unit, and the same processing as that performed by the relay controller 20 may be performed.

In the above embodiment, the radio relay station 2
However, the present invention is not limited to this, the wireless relay station 200 is not provided, and the master station is directly connected to a plurality of slave stations via a fixed wireless line. May be provided, and the master station controller 10 of the master station 100 may execute the process of measuring the reception electric field strength in the relay controller 20.

[0035]

As described above in detail, according to the receiving electric field strength measuring system according to the first aspect of the present invention, a wireless communication system in which a master station and a plurality of slave stations communicate via a fixed wireless line. In a communication system, when a master station transmits a station selection calling signal to each slave station in a polling manner, after detecting the station selection calling signal, the master station receives a data signal from the slave station, and is receiving a data signal. And measuring means for measuring the reception electric field strength at the step (c). Therefore, in a wireless communication system applied to a telemeter system or a telecontrol system, while receiving data, it is possible to receive a radio wave from each slave station and measure the received electric field strength. The received electric field strength can be automatically measured without interrupting the working line, and the propagation path in the wireless communication system can be constantly monitored and reliably secured. If an abnormality occurs in the wireless propagation path, it is possible to respond quickly.

According to a second aspect of the present invention, in the receiving electric field strength measuring system according to the first aspect, the measuring means detects data from the slave station after detecting the station selection calling signal. When a preamble signal of the signals is received, measurement of the received electric field strength during reception of the data signal is started. Therefore, after receiving the station selection call signal and the preamble signal relating to the designated slave station, the measurement of the reception field strength is started, so that the reception field strength of the designated slave station can be reliably detected. .

Further, according to the receiving electric field strength measuring system of the third aspect, in the receiving electric field strength measuring system of the second aspect, the measuring means is configured to receive the data signal received after the preamble signal. The received electric field strength is measured a predetermined number of times. Therefore, since the reception electric field strength is measured a plurality of times, it is possible to reliably detect the reception electric field strength of the designated slave station.

According to a fourth aspect of the present invention, in the receiving electric field intensity measuring system according to the third aspect, the measuring means compresses the data of the receiving electric field intensity measured a plurality of times. I do. Therefore,
Since the data of the measured received electric field strength is compressed, the capacity of the memory for storing the data can be reduced,
When transmitting the data, it is possible to quickly transmit the data in a short time, even on a line with a low transmission speed.

Further, according to the receiving electric field strength measuring system of the sixth aspect, in the receiving electric field intensity measuring system of the first or second aspect, the measuring means detects a station selection calling signal and then sets a slave station. When the preamble signal of the data signals from the base station is not received, the measurement of the received electric field strength during the reception of the data signal is started a predetermined time after the detection of the station selection calling signal. Therefore, even when the preamble signal from the slave station is not received, it is assumed that the reception has failed, and it is assumed that the data signal is being transmitted from the slave station, and the measurement of the received electric field strength is started.
Even when the preamble signal from the slave station is not received, the received electric field strength can be measured.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a telemeter wireless communication system according to an embodiment of the present invention.

FIG. 2 is a timing chart showing an operation of the telemeter wireless communication system of FIG.

FIG. 3 is a flowchart illustrating an electric field strength measurement process executed by the relay controller 20 of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Telemeter master station apparatus, 2 ... Data modem, 3 ... Wireless transceiver, 3a ... Antenna, 10 ... Master station controller, 11 ... Memory, 20 ... Relay controller, 21 ... Memory, 22 ... Timer, 23 ... Electric field strength detection Reference numeral 31: wireless transceiver, 31a: antenna, 32: telemeter slave station, 33: memory, 41: wireless transceiver, 41a: antenna, 42: data modem, 43: wireless transceiver, 43a: antenna, 100: Master station, 200, 200-1 to 200-M ... wireless relay station, 300, 300-1 to 300-N, 310-1 to 3
10-N ': slave station, 400: supervisory control device, 401: data input device, 402: data output device.

Claims (8)

[Claims] In a wireless communication system for performing communication between a master station and a plurality of slave stations via a fixed wireless line, when the master station transmits a station selection calling signal to each slave station by a polling method. And a measuring means for receiving the data signal from the slave station after detecting the station selection calling signal and measuring the received field strength during the reception of the data signal. 2. The method according to claim 1, wherein the measuring means starts measuring a received electric field strength during reception of the data signal when the preamble signal of the data signal from the slave station is received after detecting the station selection call signal. The receiving electric field strength measuring system according to claim 1, wherein: 3. The receiving electric field intensity measuring system according to claim 2, wherein said measuring means measures the receiving electric field intensity a plurality of times during reception of the data signal received after said preamble signal. . 4. The receiving electric field intensity measuring system according to claim 3, wherein said measuring means compresses the received electric field intensity data measured a plurality of times. 5. The method of compressing the data of the received electric field strength measured over a plurality of times includes calculating an average value of the data over a plurality of times, calculating a maximum value of the data over a plurality of times, 5. The system according to claim 4, wherein at least one of calculating the minimum value of the data is performed. 6. The method according to claim 1, wherein the measuring means detects a station selection calling signal and, when not receiving a preamble signal among the data signals from the slave stations, sets the data after a predetermined time from the detection of the station selection calling signal. 3. The reception electric field strength measurement system according to claim 1, wherein the measurement of the reception electric field intensity during reception of the signal is started. 7. The wireless communication system communicates via a fixed wireless line from a master station to a plurality of slave stations via at least one wireless relay station, and the wireless relay station includes: 7. The reception device according to claim 1, further comprising: a transmission unit configured to transmit the reception electric field strength measured by the measurement unit or the data obtained by compressing the data to a master station. Electric field strength measurement system. 8. The telecommunications system, wherein the wireless communication system transmits data collected by each slave station to a master station,
8. The reception electric field strength measurement system according to claim 1, wherein the system is at least one of a telecontrol system for controlling each of the slave stations from the master station.