JPH10247914A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep high reliability by surely forming a transmission path over a wide area even when a terminal station moves. SOLUTION: A signal sent from a transmission station is received by other slave station 2 within a transfer area. Each slave station 2 receives sensor information, transmission station position information and sensor position information almost simultaneously in parallel to calculate a delay time. The delay processing of the slave station 2 closet to a master station 1 is first finished, and since there is not other station making transmission at this point of time, a carrier signal is used to start transmission of a succeeding signal. The transmission station in standby in the reception state for a prescribed time after the transmission receives the first carrier signal and confirms the normal transmission state to the slave station 2. Then another slave stations 2 start checking the state of another station sequentially as the delay time elapses, and since the first slave station 2 acts like a new transmission station already and sends the carrier signal at this point of time, the following slave station 2 are in standby in the reception state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system used for a telemeter, a telecontrol system, and the like, and more particularly, to a radio communication system for transmitting data from a terminal station having a small transmission output to a master station.

[0002]

2. Description of the Related Art Telemeters and telecontrol systems that collect measurement information output from measurement devices distributed over a wide area and perform measurement control processing have been used in various fields. That is, for example, there are a wide range of things such as monitoring of river water level and collection of rainfall data, and a relatively small one such as management of gas consumption in general households.

[0003] Data transfer systems in these systems are generally broadly classified into a wired system and a wireless system. In the wired system, communication is performed by directly connecting the master station to the terminal station or indirectly connecting the terminal station to the terminal station. This method does not pose a significant problem when targeting an area where a telephone line or the like already exists, or when the target area is small even if it does not exist. However, if there is no telephone line and the target area is a wide area such as a mountain area or a lake, enormous costs will be required for wiring laying work.

On the other hand, the wireless system has no problem of wiring laying. However, the antenna output and frequency are strictly regulated by laws and regulations, and in order to transmit a large antenna output that enables long-distance transmission, it is necessary to arrange a wireless operator with a specific license. Therefore, when performing multi-point measurement in a wide area, enormous operation costs including labor costs are incurred. Further, in order to increase the antenna output, power must be supplied to the terminal station, so that wiring work is required, and electromagnetic waves may adversely affect the environment due to the large antenna output. In order to solve these problems, a method has been proposed in which data is transmitted by a relay using the terminal station as a relay station, thereby suppressing the antenna output of the terminal station. Examples of such known techniques include:
For example, there is JP-A-5-75612. In this known technique, a communication path is tabulated and managed by a terminal station to form a network system, and a table is constructed between terminal stations at system startup or periodically to search and form a data transmission path. Is what you do.

[0005]

However, the known technology has the following problems. That is, for example,
When collecting temperature, water level, and rainfall data for a wide area, the terminal station is often mounted on a vehicle such as a measuring vehicle or an observation boat. At that time, the position of the terminal station changes with time, but the above-mentioned known technique does not take such a case into consideration. In other words, according to the configuration of the above-described known technique, data transmission cannot be performed unless a table is formed by performing polling between terminal stations each time the mobile station moves, and a transmission route is formed based on the table. Therefore, it takes a long time to transmit data, during which time the terminal station may move further. Therefore, it is practically difficult to cope with the movement of the terminal station, and when the terminal station moves, it may be difficult to secure a transmission path, and the reliability is low. The present invention has been made in view of the above-described problems of the related art,
An object of the present invention is to provide a wireless communication system capable of reliably forming a transmission path in a wide area and maintaining high reliability even when a terminal station moves.

[0006]

According to the present invention, in order to achieve the above object, a plurality of terminals each comprising a sampling means for sampling a physical quantity to be sampled and a detecting means for detecting the position of the own station. And a master station that outputs a data transmission request by designating an arbitrary terminal station among the plurality of terminal stations, and wherein each of the plurality of terminal stations has physical quantity data collected by the collection means. Transmitting means for transmitting the own station position data detected by the detecting means to another terminal station or the master station, and receiving means for receiving a data transmission request from the master station or transmission data from another terminal station; In a wireless communication system comprising: one of the plurality of terminal stations transmits the physical quantity data, when the plurality of other terminal stations receive the transmission data, each of the receiving stations, Own station The position determining means determines whether the position is within a predetermined area where the transmission data is to be relayed, based on the mutual relationship between the own station position, the transmitting station position, and the master station position. Each of the receiving station groups determined to be within the predetermined area is related to the relay of the transmission data, and the priority determining unit determines the priority of the own station within the receiving station group based on the mutual relationship between the own station position and the master station position. And determine
The wireless communication system, wherein the receiving station having the first priority in the local station determined by the ranking determining means relays the received transmission data and transmits the received data using the transmitting means provided in the receiving station. Is provided. That is, in the present invention, when physical quantity data is transmitted from a certain transmitting station among a plurality of terminal stations, in order to select a terminal station to relay the data, the transmitting data is first received as a first step. Of the receiving stations, only those located within a predetermined area suitable for relaying are selected by the position determining means of each receiving station. Then, as a second stage, the priority order of each receiving station is determined by the order determining means provided for each of the receiving station groups within the predetermined area, and the data received by the first receiving station is relayed. At this time, each terminal station has detected its own station position by the detecting means, and selection by the first-stage position determining means is performed based on the mutual relationship among the own station position, transmitting station position, and master station position, The rank determination by the rank determining means in the second stage is performed based on the mutual relationship between the own station position and the master station position. Therefore, even when the position of the transmitting station or its own station changes with time, a station to be relayed is appropriately selected in a form corresponding to the position at that time, and the selection is repeated to form a transmission route by relay. At this time, the transmission route is determined by the position determining means and the order determining means on the receiving station side, and the transmitting station can perform transmission before the transmission route is determined.
Data transmission is completed in a short time. Therefore, even when the terminal station moves, a data transmission path to the master station can be reliably formed, so that high reliability can be maintained.

Preferably, in the wireless communication system, the position determination means has a radius r as the predetermined area, with a straight line connecting the transmitting station and the master station as a line symmetry axis with the transmitting station as a circle center. In addition, a wireless communication system is provided in which a fan-shaped region having a central angle of 2θ is used as a criterion. Thus, for example, by setting θ <30 °, a radio interference state in which two or more terminal stations start relaying can be avoided, and by setting r to be equal to or less than the maximum reach of radio waves, the transmission path can be reduced. It is possible to reduce the probability of occurrence of transmission failure that is interrupted on the way. Therefore, reliability can be improved.

Preferably, in the wireless communication system, the rank determining means sets a delay time at the start of relay transmission of the received transmission data based on a mutual relationship between a local station position and a parent station position. Delay time setting means, and relay stop means for stopping relay transmission of the own station when relay transmission from another station within the predetermined area has already started after the delay time has elapsed. A wireless communication system is provided. Thereby, when determining the priority, it is sufficient to determine only the presence or absence of relay transmission from any of the other receiving stations other than the own station, and it is not necessary to exchange position information with all the other receiving stations, The ranking can be determined quickly. Also, since the priority is automatically determined according to the delay time, the first priority is determined first, and after the determination, the relay transmission can be started immediately without waiting for the determination of all ranks. Further speedup can be achieved.

[0009] More preferably, in the wireless communication system, the delay time setting means sets the delay time according to a linear distance L1 between the own station and the master station. You. As a result, the delay time can be determined in a very simple manner, and a transmission route that is almost the shortest can be formed.

[0010] More preferably, in the wireless communication system, the delay time setting means includes a distance L of a perpendicular line drawn from a position of the own station to a straight line connecting the transmitting station and the master station.
2. A wireless communication system is provided, wherein a delay time is set according to 2. As a result, even if the distance from the master station is far, the delay time becomes shorter if the distance is closer to the straight line between the transmitting station and the master station. Therefore, it is possible to form a transmission route that is almost the shortest while suppressing the maximum value of the delay time to some extent.

Preferably, in the wireless communication system, the delay time setting means includes: a point M located on a straight line connecting the transmitting station and the master station and at a predetermined distance ro from the transmitting station; A delay time is set according to a distance L3 from the wireless communication system. As a result, even if the distance from the master station is far,
The closer the point is to the point M on the straight line between the transmitting station and the master station, the shorter the delay time becomes. Therefore, it is possible to form a transmission route that is almost the shortest while suppressing the maximum value of the delay time to some extent.

Also preferably, in the wireless communication system, one of the plurality of terminal stations that has performed the relay transmission is a terminal station that has received the relay transmission within a predetermined time after the relay transmission. Further comprises relay determination means for determining whether or not further relay transmission has been performed, and
When the relay determination unit determines that the further relay transmission has not been performed, the same relay transmission is performed again by the transmission unit.

[0013] More preferably, in the wireless communication system, each of the plurality of terminal stations, which has received the second relay transmission by the relay transmission station, is configured such that the position determination means determines whether or not the first relay transmission has been performed at the time of the first relay transmission reception. A wireless communication system is characterized in that a determination is made using an area different from the predetermined area as a determination criterion. That is, for example, if the predetermined area is a fan-shaped area having a radius r centered on the transmitting station and a central angle 2θ at the time of the first relay transmission reception, when the relay transmission is received again, the predetermined area has the same shape as this area. In addition, a region offset by an angle 2θ around the transmitting station may be used as a criterion. As a result, even if a further relay station is not found in the first transmission and normal transmission cannot be performed, the area setting change is repeated so that a further relay station can always be found and normal transmission can be performed in the second and subsequent transmissions. Can be prevented from being interrupted on the way.

Preferably, in the wireless communication system, each of the plurality of terminal stations includes a solar cell,
A wireless communication system further comprising a storage battery for storing a surplus of electrical energy generated by the solar cell. This eliminates the need for a wiring facility for supplying power to the terminal station, so that the cost required for installation and maintenance can be significantly reduced.

Also preferably, in the wireless communication system, each of the plurality of terminal stations includes a radio wave direction detecting means and a radio wave strength detecting means for respectively detecting a direction and a strength of the radio wave received by the receiving means, A wireless communication system, further comprising: a position estimating unit that estimates a position of a transmitting station that has transmitted the radio wave based on a detection result of the direction detecting unit and the radio wave intensity detecting unit. As a result, the position of the transmitting station can be estimated on the receiving station side, so that it is not necessary to include the position information of the transmitting station in the transmission data from the transmitting station, and the transmission signal can be simplified.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. The present embodiment is an embodiment of a wireless communication system that collects and transmits physical quantity data such as temperature, water level, turbidity, and rainfall in and around a lake.
FIG. 1 is a conceptual diagram showing a system configuration of a wireless communication system according to the present embodiment. One master station 1 and a large number of terminal stations (hereinafter, referred to as slave stations as appropriate) arranged over a wide area of a lake and its surroundings. ) 2). The master station 1 designates an arbitrary slave station 2 among a number of slave stations 2 in accordance with a preset address assigned to each slave station 2 (or by designating a coordinate value or the like of each slave station 2). And outputs a data transmission request signal for requesting the specified slave station 2 to transmit data. Then, the master station 1 directly or indirectly receives the data transmitted from the designated slave station 2, and performs a predetermined process on the received data. At this time, the master station 1 immediately sends the reception report signal to all slave stations 2 without delay at the same time as obtaining all the requested data (ie, at the same time as the completion of the reception of the sensor position signal 100b3 described later). Output, and the data transmission process of all the slave stations 2 is terminated. Based on the data transmission request signal of the master station 1, the slave station 2 extracts the physical quantities from sampling means (for example, a sensor or the like, not shown) for sampling physical quantities to be collected such as temperature, water level, turbidity, and rainfall. It has both a function of acquiring and transmitting it as a data signal and a relay function of relaying this data signal transmitted by another slave station 2 (details will be described later).

The data signal from the slave station 2 and the master station 1
2 (a) to 2 (c) show the structures of the data transmission request signal and the reception report signal, respectively. FIG. 2 (a) to (c)
, The data signal 100 and the data transmission request signal 20
0 and the reception report signal 300 are radio signals, respectively, and are carrier signals 100a and 1002 having a specific frequency (for example, 40 MHz) predetermined for each system.
00a, 300a and these carrier signals 100a, 2
The information signals 100b, 200b, and 300b are formed by applying a certain modulation to the signals 00a and 300a.

The information signal 100b includes a sensor information signal 100b1 representing the physical quantity collected by the sensor, a transmitting station position signal 100b2 representing the position of the transmitting station that transmitted the radio signal 100 immediately before, and a sensor position representing the position of the sensor. And a signal 100b3. Information signal 200
b is an address signal (or coordinate signal) 200b1 for specifying the slave station 2 of the other party, a master station position signal 200b2 indicating the position of the own station (master station), and a request for data transmission from the master station. And a master station identification signal 200b3 for identifying that the transmission has been made. Information signal 3
00b is a transfer end request signal for requesting transfer end.

The information signals 100b, 200b, 30
The method of 0b modulation includes, for example, amplitude modulation, frequency modulation, and phase modulation. As an example, FIG. 3 shows an example in which the information signal 100b is formed by amplitude modulation. In this case, as shown in FIG. 3, the information signal 100b is a carrier signal 10b.
It is formed by changing only the amplitude of 0a, and has the same frequency and phase. The information signal 100b indicates the above-described sensor information, transmission station position information, and sensor position information by an envelope (indicated by a broken line) of the waveform. Other information signals 200b, 3
For 00b, modulation is performed in the same manner.

Next, the configuration and functions of the slave station 2, which is a main part of the present embodiment, will be sequentially described in detail. First, a perspective view showing the external structure of the slave station 2 is shown in FIG. In FIG. 4, the slave station 2 includes an antenna 6 for transmitting and receiving a radio signal,
A housing 140 for storing an electronic circuit (not shown, detailed functions of which will be described later) constituting a transmitting / receiving device, a laying leg 142 buried in the ground to fix the entirety, And a storage battery 141 for storing electric power.

The housing 140 is waterproof and dustproof because it is installed outdoors. The storage battery 141 is configured to store a surplus of the electric energy generated by the solar cell 139. For example, the surplus of the electric energy generated by the sunlight in the clear daylight is temporarily stored in the storage battery 14.
After being stored in 1, it is used for power supply at night or in bad weather. Some of the slave stations 2 are installed, for example, on a measuring vehicle or an observation ship, and their positions change with time.

FIG. 5 is a functional block diagram showing the functional configuration of the slave station 2 having the above structure. The signal flow is indicated by arrows. As shown in FIG. 5, the slave station 2 includes, as components related to the receiving side, a receiving device 8 that receives and demodulates a radio signal from the antenna 6, and detects and processes a signal transmitted from the master station. The master station signal processing device 9, the master station position storage device 10 that stores the position of the master station 1 in advance, and the position information of the transmitting station (the master station 1 or another slave station 2) that transmitted the radio wave are obtained. The transmitting station position detecting device 11 and the GPS (= Glo
bal Positioning System (Global Positioning System) and the like, and a local station position detecting device 12 for detecting the position of the local station. In addition, the antenna 6
Switching for transmission or reception is performed by the antenna switching device 7. The slave station 2 includes, as components related to the transmitting side, an input terminal 15 for inputting a signal from a sensor that has collected a physical quantity, and data information to be transmitted including own station position information from the own station position detecting device 12. A transmission data storage device 16 for temporarily storing, a modulation device 20 for modulating a carrier signal with data information to be transmitted, and a transmission device 21 for amplifying a signal output from the modulation device 20 and transmitting the amplified signal to the antenna 6
And Further, the slave station 2 has a unique configuration that is a feature of the present embodiment. The slave station 2 includes a relay determination device 14 that selects whether or not the own station should relay, and a delay time calculation that determines a delay time (described later) for a transmission process. A device 13; a delay device 17 for delaying processing based on the delay time;
It has another station status detecting device 18 for detecting the status of the other station, and a transmitting device starting device 19 for controlling the timing of the modulation start of the modulation device 20. Each of the above components 7 to 21
Is monitored and controlled by the central processing unit 22. And all components 7 including this
22 are arranged in the housing 140 described above.

In the above configuration, the transmitting device 21 and the antenna 6 constitute transmitting means for transmitting the physical quantity data collected by the collecting means and the own station position data detected by the detecting means to another terminal station or a master station. , The receiving device 8 and the antenna 6 constitute a receiving means for receiving a data transmission request from the master station or transmission data from another terminal station.

The operation of the slave station 2 having the above configuration will be described with reference to the operation flowchart shown in FIG. 6 and 5, first, in step 400, the antenna switching device 7 switches the antenna 6 to the reception state, and the slave station 2 stands by in this reception state. When the radio signal is received by the antenna 6, the procedure proceeds to step 401.

In step 401, the receiving device 8 determines whether the radio signal is one of the radio signals 100, 200, and 300 (that is, the carrier signal 10
0a, 200a, and 300a are included). If the carrier signals 100a, 200a, and 300a are not included, the process returns to step 400 to continue the standby state. If the carrier signals 100a, 200a, and 300a are included, the received signal is any of the radio signals 100, 200, and 300. Therefore, this signal is demodulated and output to the master station signal processing device 9, and the procedure 402 Move to

In step 402, the master station signal processing device 9
For example, based on a difference in frequency or a difference in modulation method, whether the signal is a reception report signal 300 from the master station 1 (ie, whether a portion transmitted next to the carrier signal is the transfer end request signal 300b) Is determined. If it is the reception report signal 300, the process returns to the procedure 400 to continue the standby state. If it is not the reception report signal 300, the procedure goes to step 403.

In step 403, the master station signal processing device 9
Similar to the procedure 402, whether the signal is the transmission request signal 200 from the master station 1 based on the difference in frequency or the difference in modulation method (ie, whether the portion transmitted next to the carrier signal is the address signal 200b1) Is determined. If it is the transmission request signal 200, the procedure proceeds to step 404 and thereafter, the procedure is related to the transmission of the own station data.
If it is not 00, the signal becomes the data signal 100 transmitted from the other slave station 2, so that the procedure proceeds to the step 407 and thereafter becomes the relay procedure of the data. Hereinafter, these will be described separately.

(1) Transmission of own station data In step 404, the master station signal processing device 9 determines whether the request is a transmission request to the own station (that is, whether the address signal 200
b1 is the own station). If it is not a transmission request to the own station, the procedure returns to the procedure 400 again to be in a standby state. If it is a transmission request to the own station, the procedure goes to step 405.

In step 405, the master station signal processing device 9
It informs the relay determination device 14 and the delay time calculation device 13 that there has been a transmission request from the master station 1. Upon receiving this request, the relay determination device 14 informs the transmission data storage device 16 that there has been a request from the master station 1. Thereby, the transmission data storage device 16 collects, via the input terminal 15, sensor information indicating the physical quantity collected by the sensor and sensor position information indicating the position of the sensor, and transmits the local station position from the local station position detecting device 12. These are temporarily stored together with the information. On the other hand, the delay time calculating device 13 calculates the delay time 0
Is output to the delay device 17. Then, step 406
Move to

In step 406, first, the transmission data storage device 16 sends the sensor information, the own station position information, and the sensor position information to the delay device 17 collectively. At this time, since the delay time is set to 0 in the previous procedure 405, the delay device 17 immediately sends them to the modulation device 20. At the same time, the relay determination device 14 makes a transmission request to the transmission device activation device 19, whereby the transmission device activation device 19 outputs a signal for starting modulation of the modulation device 20 and a signal for activating the transmission device 21. Output. Thereby, the modulation device 20 modulates the carrier signal 100a (see FIG. 2) based on the sensor information, the own station position information, and the sensor position information to form the sensor information signal 100b1, the transmitting station position signal 100b2, and the sensor position signal 100b3. Then, finally, the data signal 100 including the carrier signal 100a and the information signal 100b is output to the transmitting device 21.
Then, the transmission device 21 transmits the data signal 100 immediately via the antenna 6 switched to the transmission state by the antenna switching device 7. As a result of the above procedure, after receiving the transmission request signal 200 from the master station 1, transmission of the data signal 100 is started without delay. When the transmission is completed, the process returns to step 400 and waits in the reception state.

(2) Relay of data signal of other station In step 407, the receiving device 8
00 is demodulated. At this time, the sensor information signal 100b1 and the transmission station position signal 10
0b2 and the sensor position signal 100b3, the sensor information, the transmitting station position information transmitting the radio wave, and the sensor position information are demodulated as electric signals. The transmitting station position information is output to the transmitting station position detecting device 11, where the position of the transmitting station is specified. The position of the transmitting station 3 specified by the transmitting station position detecting device 11 is further added to the delay time calculating device 13.
And the relay determination device 14 (procedure 40 described later).
8 and procedure 409). Further, the sensor information and the sensor position information are output to the transmission data storage device 16, and the transmission data storage device 16 temporarily stores these together with the own station position information from the own station position detection device 12. When the procedure 407 ends, the procedure moves to the procedure 408.

In step 408, a signal indicating the position of the master station 1 from the master station position storage device 10 is input to the delay time calculator 13. The delay time calculating device 13 sets a transfer area indicating a range suitable for operating as a relay station according to the signal and the signal indicating the transmitting station position input from the transmitting station position detecting device 11 in step 407. Set. An example of a method for setting the transfer area will be described with reference to FIG. In FIG. 7, the transmitting station 3 which transmitted the data signal 100 among the slave stations 2
Are transmitted concentrically, and the transfer area is defined by a radius r and a central angle 2θ, with the straight line connecting the transmitting station 3 and the master station 1 as the axis of symmetry with the transmitting station 3 as the center of circle. It is a fan-shaped area. Here, r is, for example, equal to or less than the maximum reach of radio waves. Θ has an optimum value depending on the arrangement density of the slave stations 2 and the intensity of the radio wave transmitted from each slave station 2.
It shall be less than 0 °. The transfer area set in this way is output from the delay time calculation device 13 to the relay determination device 14. When the procedure 408 ends, the procedure moves to the procedure 409.

In step 409, the relay determining device 14 determines whether the data signal 100 has been transmitted for the first time based on the transmitting station position input from the transmitting station position detecting device 11 in step 407, 3 to determine whether the data has been retransmitted. If it has been transmitted for the first time, the process immediately proceeds to step 411. If it has been retransmitted, the process proceeds to step 410, and in step 408, the transfer area input from the delay time arithmetic unit 13 is updated. This updating procedure will be described with reference to FIG. FIG. 8 shows that the transmitting station 3
Shows an example in which it is determined that has been retransmitted. That is, as described later, when the transmitting station 3 cannot detect the carrier signal 100a of the next station, the transmitting station 3 performs retransmission after a certain standby time. Each slave station 2 detecting this retransmission,
The transfer area set in step 408 is updated in step 410.
FIG. 8 shows a specific update example in which the transfer area 1 is set as shown in FIG. 7 but the slave station 2 to be relayed does not exist. The transfer area 2 is reset by offsetting the fan-shaped area counterclockwise (see the arrow) by 2θ. As a result, a new transfer area 2
There are four slave stations 2 inside, and a further optimum slave station can be selected from among them in a procedure described later. Note that if the slave station 2 does not exist in the transfer area 2 again, the transmitting station 3 performs re-transmission, and in this case, a further transfer area is set by further offsetting. Hereinafter, such an offset operation is repeated. As a result, the transferable slave station 2 can always be found, so that transmission failure in which the transmission path is interrupted halfway can be prevented.
When the procedure 410 ends, the procedure moves to the procedure 411.

In step 411, the relay determining device 14 inputs the own station position from the own station position detecting device 12, and
The position of the master station 1 is input from the master station position storage device 10, and it is determined whether or not the own station is located within the transfer area based on these two and the position of the transmitting station 3 already input in step 407. I do. If it is determined that the area is out of the transfer area, the procedure returns to step 400 to be in a standby state. If it is determined that it is within the transfer area,
That fact is output to the transmitting device starting device 19 and the procedure 41 is executed.
Move to 2. In the example of FIG. 7 described above, five slave stations 2
Is determined to be within the transfer area, and the procedure moves to step 412.

In step 412, the delay time calculating device 13
Calculates a predetermined delay time Δt based on the position of the transmitting station 3, the position of the master station 1, and the position of the own station. This delay time Δ
The method of calculating t will be described with reference to FIG. FIG. 9 shows three examples of the method of calculating the delay time. That is, FIG.
(A) is a method of setting the delay time Δt of the own station 2 according to the linear distance L1 between the slave station (own station) 2 to be relayed and the master station 1 (in this case, proportional to L1). Yes, FIG. 9
(B) corresponds to a distance L2 of a perpendicular line lowered from the position of the own station 2 to a straight line connecting the transmitting station 3 and the master station 1 (in this case, L2
9 (c) is a method of setting the delay time Δt of the own station 2 on a straight line connecting the transmitting station 3 and the master station 1 and a predetermined distance ro (fixed) from the transmitting station 3. This is a method of setting the delay time Δt of the own station 2 in accordance with the distance L3 to the point M at (value) (in this case, proportional to L3).
Note that the calculation of the delay time Δt is performed by the receiving apparatus 21.
Then, the reception of all parts of the data signal 100 is completed and starts (see FIG. 11 described later). Delay time Δ
When t is determined, the value is output to the delay device 13 and the procedure goes to step 413.

In step 413, the delay device 17 completes the calculation of the delay time Δt (this calculation time can be considered to be the same in all the slave stations 2) after the reception by the receiving device 8 is completed, and further thereafter It waits until the delay time Δt has elapsed. After waiting for this delay time Δt, the delay device 17
Outputs the sensor information, the own station position information, and the sensor position information to the modulation device 20, and proceeds to step 414.

In step 414, the delay device 17 outputs an operation command to the other station status detecting device 18. That is, during this time, the receiving device 8 continues to receive radio waves, and any one of the carrier signals 100a, 200a, and 300a.
If one is detected, the demodulated signal is input to the other station information detecting device 18. Therefore, when an operation command is issued, the other station status detecting device 18 determines whether another slave station 2 in the transfer area has already started relay transmission based on this signal (the carrier signal detected by the receiving device is (Whether the signal is a carrier signal 100a from another station). If there is a carrier signal 100a from another station, it is determined that another station is already starting relay transmission, and
It returns to 00 and enters a standby state. Carrier signal of other station 10
If 0a does not exist, the other station status detection device 18 requests the transmission device activation device 19 to transmit so that the own station becomes a relay station, and the transmission device activation device 19 transmits a control signal for starting modulation to the modulation device. 20 to start modulation of the sensor information, the own station (transmitting station) position information, and the sensor position information already output from the delay device 17 to the modulation device 20. At the same time, the transmitting device activation device 19 also outputs an activation command to the transmitting device 21. As a result, the modulation device 20 becomes
The carrier signal 100a (see FIG. 2) is modulated based on the two pieces of information to obtain the sensor information signal 100b1 and the transmitting station position signal 1.
00b2 and a sensor position signal 100b3, and finally output to the transmitting device 21 as a data signal 100 including a carrier signal 100a and an information signal 100b. At the same time, the transmission device 21 immediately transmits the data signal 100 via the antenna 6 switched to the transmission state by the antenna switching device 7. When transmission is completed, step 416
Move on to

In step 416, the antenna switcher 7 switches the antenna 6 back to the receiving state, and the slave station 2 waits in this receiving state for a predetermined period of time. During this time, the receiving device 8 continues to receive radio waves, and when a radio signal is received by the receiving device 8 via the antenna 6,
Move to step 417.

In step 417, the receiving device 8 and the master station signal processing device 9 make the same determination as in steps 401 to 403, thereby determining whether this radio signal is a further relay radio signal 100 from the next station. I do. That is, if the carrier signal 100a is not included in the radio signal, it is determined that the slave station 2 is not in the transfer area and the normal transmission could not be performed in the first transmission, and the procedure returns to the procedure 415 to perform the retransmission. If the radio signal includes the carrier signal 100a, it is determined that normal transmission has been successfully performed, and the process returns to step 400 and waits in a reception state.

It should be noted that, of the above processing procedures, the procedure 411
When one transmitting station among a plurality of terminal stations transmits physical quantity data and the transmitting data is received by a plurality of other terminal stations, the receiving station determines whether the position of the own station should relay the transmitting data. This corresponds to a position determining means provided for determining whether or not the mobile station is within the area based on the mutual relationship between the own station position, the transmitting station position, and the master station position. Also, steps 412 to 414
Each of the receiving station groups determined by the position determining means that the own station position is within the predetermined area is determined by the receiving station group within the receiving station group based on the mutual relationship between the own station position and the master station position with respect to the relay of transmission data. It corresponds to a rank determining means provided for determining the priority. The procedure 415 constitutes a procedure in which the receiving station having the first priority in the own station in the rank determining means relays and transmits the received transmission data by the transmitting means provided in the receiving station. Further, procedures 412 and 413
The delay time when starting the relay transmission of the received transmission data corresponds to a delay time setting unit that sets the delay time based on the mutual relationship between the own station position and the master station position. If the relay transmission from another station within the predetermined area has already started, the relay station corresponds to a relay stop unit that stops the relay transmission of the own station. Procedures 416 and 417
Is provided for determining whether one of the plurality of terminal stations that has performed the relay transmission has performed the further relay transmission by the terminal station that has received the relay transmission within a predetermined time after the relay transmission. The procedure that corresponds to the relay determination means and returns from step 417 to step 415 constitutes a procedure in which the same relay transmission is performed again by the transmission means when the relay determination means determines that no further relay transmission has been performed. further,
Steps 409 to 411 are performed in each of the receiving stations that have received the relay transmission again by the relay transmitting station among the plurality of terminal stations. Configure the procedure to do.

Here, the procedures 400 to 417 described above are performed.
10 and FIG. 1 show an example of relaying from one transmitting station 3 to the next slave station 2 achieved by performing the processing procedure of FIG.
1 will be described. FIG. 10 is an arrangement diagram of the slave station 2 in this case, and FIG. 11 is a timing chart showing a series of transmission and reception operations. 10 and 11, the signal A transmitted by the transmitting station 3 is transferred to a transfer area (radius r and central angle 2θ).
Are received by five slave stations 2a to 2e existing in the network. Each of the slave stations 2a to 2e has a different timing for starting to receive the signal A depending on the delay time in the previous processing, but each of the slave stations 2a to 2e starts receiving before the carrier signal portion of the signal A ends. As a result, the sensor information signal, the own station (transmitting station) position signal, and the sensor position signal, which are the main parts of the signal, are simultaneously received. After the reception of the sensor position signal is completed, the five slave stations 2a to 2e simultaneously start calculating the delay time. The delay time at this time is based on the method shown in FIG. In this case, as shown in FIG. 10, since the slave station 2e is closest to the master station 1 and L1 is small, the delay processing ends first and the investigation of the status of the other station is started (see the procedure 414 described above). Since there is no other station transmitting at this time, the transmission of the signal B is started (performed in the order of carrier signal → sensor information signal → local station position signal → sensor position signal). The transmitting station 3, which has been in the receiving state for a predetermined time after the transmission, receives the first carrier signal of the signal B from the slave station 2e at this time, and confirms normal transmission to the slave station 2e. Thereafter, the other slave stations 2d, 2c, 2b, 2a start investigating the status of the other station in this order as the respective delay times elapse, but at that point, at least the slave station 2
Since e has already become a new transmitting station and has transmitted the signal B (specifically, the carrier signal portion), these slave stations 2a to 2
d enters the receiving state and waits. By sequentially performing the above processing, sensor information and sensor position information are finally transmitted to the master station 1 via the plurality of slave stations 2.

As described above, according to the present embodiment, when the slave station 2 to be relayed is selected, it is first determined whether or not the slave station 2 exists in the transfer area.
When the final relay station is determined from the group of slave stations that are the relay candidates,
This is performed based on the mutual positional relationship between the own station 2, the transmitting station 3, and the master station 1. Therefore, even when the position of the transmitting station 3 or the own station 2 changes with time, a slave station to be relayed is appropriately selected in a form corresponding to the position at that time, and the selection is repeated to form a transmission route by relay. Is done. In addition, at this time, since the transmission route is autonomously determined by the slave station 2 receiving the data, the transmission station 3 can perform transmission before the transmission route is determined, so that the data transmission is completed in a short time. .
Therefore, even when the transmitting station 3 and the other slave stations 2 move, for example, installed on a measuring vehicle or an observation ship, or when a part of the slave station 2 breaks down, the data transmission path to the master station 1 is established. Since it can be reliably formed, high reliability can be maintained.

When one relay slave station 2 is finally determined from a plurality of relay candidate slave stations 2 within the transfer area, a carrier signal 100 from any of the other slave stations 2 other than the own station is determined.
It is sufficient to determine only the presence / absence of transmission a (see procedure 414), and it is not necessary to exchange position information with every other slave station 2 other than the own station in the transfer area, so that the determination can be made quickly.

Although the transfer area is a fan-shaped area having a radius r and a central angle 2θ, by setting θ <30 ° here,
When the antenna outputs of the slave stations 2 are the same, it is possible to avoid an interference state in which two or more slave stations 2 determine their own stations as relay stations and start transmission. By setting r to be equal to or less than the maximum reach of the radio wave, it is possible to absorb variations in the antenna output of each slave station 2 and to reduce the probability of occurrence of transmission failure in which the transmission path is interrupted halfway. Therefore, the reliability can be further improved.

Further, since the slave station 2 is provided with the solar cell 139 and the storage battery 141, wiring equipment for supplying power to the slave station 2 becomes unnecessary, so that the cost required for installation and maintenance can be greatly reduced. Can be.

In determining the delay time Δt,
If the setting is made in accordance with the linear distance L1 between the own station 2 and the master station 1 as shown in FIG.
There is an effect that can be determined. Also, as shown in FIG. 9 (b), if the distance is set in accordance with the distance L2 of the perpendicular length drawn straight down between the transmitting station 3 and the master station 1, even if it is far from the master station 1, the transmitting station 3 and the master station 1 If the distance is closer to the straight line between the stations 1, the delay time Δt becomes shorter, so that the maximum value of the delay time Δt can be suppressed to some extent. Similarly, if the distance is set in accordance with the distance L3 from the point M on the straight line between the transmitting station 3 and the master station 1 as shown in FIG. Since the delay time Δt is shortened, there is an effect that the maximum value of the delay time Δt can be suppressed to some extent. 9A to 9C, it is possible to form a transmission route that is almost the shortest route. This will be described with reference to FIG. FIG. 12 shows that, when a large number of slave stations 2 are arranged between the transmission station 3 and the master station 1 which are approximately 18 km apart from each other in a straight line, the relay route is established by each of the methods shown in FIGS. The example when formed is shown in comparison. Note that the radius of the transfer area is r = 5 km and θ = 50 °. In addition, a case where no delay calculation is performed is also shown to clarify the effect. In this case, as a result of not performing the delay calculation, a station closest to the transmitting station 3 among the slave stations 2 in the transfer area is selected and relayed. FIG.
As shown in FIG. 2, the length of the relay route is the shortest in the method of FIG. 9B, 21.1 km, and then the length of the relay route is FIG.
21.2 km which is almost the same as that of FIG.
9 (a) is slightly longer than these two.
It is 3.5 km. However, all three are shorter than 24.5 km when no delay operation is performed. Looking at the number of relay stations, the methods shown in FIGS. 9A to 9C are all four or five stations, which is much less than the nineteen stations in which no delay calculation is performed, and is more efficient. You can see that the relay is being performed. Therefore, it can be seen that the influence of a failure or the like is extremely small and the reliability is high.

In the above embodiment, the transmitting station 3
In order to detect the position at the receiving station 2, the position information of the own station is added to the radio wave transmitted by the transmitting station 3 (see the transmitting station position signal 100b2 in FIG. 2A), but the present invention is not limited to this. . That is, as the radio wave direction detecting means, for example, the antenna 6 is mechanically moved in the circumferential direction, or a large number of antennas 6 are arranged in the circumferential direction to detect the transmission direction of the radio wave. The mobile station 2 may be provided with a radio wave intensity detecting means for measuring the intensity of the radio wave and a position estimating means for estimating the position of the transmitting station 3 based on the direction and intensity of the radio wave received from the two detection results. In this case, since the position of the transmitting station 3 can be estimated on the side of the receiving slave station 2, the transmitting station 3 does not need to include the transmitting station position information in the transmission data, and the transmission signal can be simplified. This has the effect.

[0048]

According to the present invention, even when a terminal station moves, a transmission path can be reliably formed in a wide area, and high reliability can be maintained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a system configuration of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a data signal from a slave station, a data transmission request signal from a master station, and a reception report signal.

FIG. 3 is a diagram illustrating an example of forming an information signal by amplitude modulation.

FIG. 4 is a perspective view illustrating an appearance structure of a slave station.

FIG. 5 is a functional block diagram showing a functional configuration of a slave station.

FIG. 6 is a flowchart illustrating an operation of a slave station.

FIG. 7 is a diagram illustrating an example of a transfer area setting method.

FIG. 8 is a diagram illustrating a procedure for updating a transfer area.

FIG. 9 is a diagram illustrating three examples of a method of calculating a delay time.

FIG. 10 is a layout diagram of slave stations for explaining an example of relay from one transmitting station to the next slave station.

11 is a timing chart showing a series of transmission and reception operations in the arrangement of FIG.

FIG. 12 is a diagram comparing an example in which a relay route is formed by each of the methods of FIGS. 9 (a) to 9 (c).

[Explanation of symbols]

 Reference Signs List 1 master station 2 slave station (terminal station) 3 transmitting station (terminal station) 6 antenna (transmitting means, receiving means) 8 receiving apparatus (receiving means) 12 own station position detecting apparatus (detecting means) 15 input terminal (collecting means) 21 transmitting device (transmitting means) 139 solar cell 141 storage battery

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Nagaoka 502, Kandachicho, Tsuchiura-shi, Ibaraki Pref.

Claims (10)

[Claims] 1. A plurality of terminal stations each provided with a sampling means for sampling a physical quantity to be collected, and a detecting means for detecting a position of the own station, and by designating an arbitrary terminal station among the plurality of terminal stations. A master station that outputs a data transmission request,
And, each of the plurality of terminal stations, transmitting means for transmitting the physical quantity data collected by the collection means and the own station position data detected by the detection means to another terminal station or the master station, from the master station And a receiving means for receiving data transmission request or transmission data from another terminal station, wherein one of the plurality of terminal stations transmits the physical quantity data, and the transmission data Is received by a plurality of other terminal stations, each of the receiving stations determines whether the own station position is within a predetermined area where the transmission data is to be relayed, based on the own station position / transmitting station position / parent station position. Each of the receiving station groups determined by the position determining means based on the mutual relationship and determined by the position determining means that the own station position is within the predetermined area is related to the relay of the transmission data with respect to the own station position and the master station. Rank The priority order of the own station in the group of receiving stations is determined by the order determining means based on the mutual relationship of the receiving stations. The receiving station whose own station priority is first in the order determining means is provided in the receiving station. A wireless communication system, wherein the transmission means relays and transmits the received transmission data. 2. The wireless communication system according to claim 1, wherein said position determination means sets said predetermined area as a center of a circle centered on said transmitting station and a straight line connecting said transmitting station and said master station as a line-symmetric axis. , A sector having a radius r and a central angle 2θ is used as a criterion. 3. The wireless communication system according to claim 1, wherein said rank determining means determines a delay time when relay transmission of the received transmission data is started based on a mutual relationship between a local station position and a parent station position. Delay time setting means for setting, and after the delay time has elapsed, relay stop means for stopping relay transmission of the own station if relay transmission from another station within the predetermined area has already started. A wireless communication system comprising: 4. The wireless communication system according to claim 3, wherein said delay time setting means sets a delay time according to a linear distance L1 between the own station and said master station. 5. The wireless communication system according to claim 3, wherein said delay time setting means sets the delay time according to a distance L2 of a perpendicular line lowered from a position of the own station to a straight line connecting said transmitting station and said master station. A wireless communication system characterized by setting. 6. The wireless communication system according to claim 3, wherein said delay time setting means includes a point M located on a straight line connecting said transmitting station and said master station and at a predetermined distance ro from said transmitting station. A wireless communication system, wherein a delay time is set according to a distance L3 from the own station. 7. The wireless communication system according to claim 1, wherein one of the plurality of terminal stations that has performed the relay transmission has received the relay transmission within a predetermined time after the relay transmission. The relay station further includes relay determination means for determining whether or not the terminal station has performed further relay transmission, and when the relay determination means determines that the further relay transmission has not been performed, the same relay transmission is performed by the transmission means. Wireless communication system. 8. The wireless communication system according to claim 7, wherein each of the plurality of terminal stations that has received the second relay transmission by the relay transmission station has the first position determined by the position determination unit. A wireless communication system, wherein the determination is performed using an area different from the predetermined area at the time as a determination criterion. 9. The wireless communication system according to claim 1, wherein each of said plurality of terminal stations further includes a solar cell and a storage battery for storing a surplus of electric energy generated by said solar cell. A wireless communication system, comprising: 10. A radio communication system according to claim 1, wherein each of said plurality of terminal stations includes a radio wave direction detecting means and a radio wave strength detecting means for respectively detecting a direction and a strength of a radio wave received by said receiving means; A wireless communication system further comprising: position estimating means for estimating the position of a transmitting station that has transmitted the radio wave based on the detection results of the radio wave direction detecting means and the radio wave intensity detecting means.