JP2007150811A - Measured data transmission controller of sensor terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the transmission start time for measured data autonomously and distributively by each sensor terminal at a low cost and to avoid congestion due to concentration of measured data signals. <P>SOLUTION: The measured data transmission controller of the sensor terminal for performing the control of transmitting the measured data measured by the sensor terminal to a data center at the prescribed transmission start time comprises: a delay time calculation means for inputting a numerical value intrinsic to the sensor terminal, performing hash function computation and outputting delay time corresponding to a generated has value; and a transmission start time control means for performing the control of delaying the transmission start time of the measured data of the sensor terminal for the delay time outputted from the delay time calculation means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a measurement data of a sensor terminal that controls measurement data transmission start time autonomously and distributedly at each sensor terminal in a wide-area telemetry system that transmits measurement data measured by sensor terminals arranged in a plurality of regions to a data center. The present invention relates to a transmission control apparatus.

FIG. 6 shows a configuration example of the wide area telemetry system. In the figure, a plurality of sensor terminals 51-1 to 51-n are grouped for each wireless communication area of a plurality of wireless base stations 52-1 to 52-m (n> m). Stations are connected by wireless lines. The data center 14 is connected to each of the radio base stations 52-1 to 52-m via the relay station 13.
In the conventional wide-area telemetry system, the measurement data measured by each of the sensor terminals 51-1 to 51-n is accumulated, and when a predetermined transmission start time (for example, every day at midnight) is reached, the corresponding radio base station The transmission of measurement data is simultaneously started to the data center 54 via the 52-1 to 52-m and the relay station 53.

  Here, since the data length of the measurement data signal transmitted by each sensor terminal is short, even if a plurality of sensor terminals start transmitting to one radio base station at the same time, the probability that congestion will occur in the radio base station is small. Rather, in the network from each of the radio base stations 52-1 to 52-m to the data center 54 or the data server of the data center 54, the measurement data transmitted from the plurality of sensor terminals 51-1 to 51-n at the same time. Concentration may cause an overload, which may cause a communication error or operation error.

In order to deal with such a problem of overload due to simultaneous transmission of sensor terminals, a method of setting the transmission start times to be different at each sensor terminal has been conventionally considered (Patent Document 1). That is, the time for starting transmission of measurement data from a plurality of sensor terminals is shifted, and the load on the network and data server is distributed to prevent communication abnormality and operation abnormality.
JP 2002-24423 A

  By the way, the conventional method of setting the transmission start time to be different at each sensor terminal requires a mechanism for performing relative time management between the sensor terminals. For example, each sensor terminal is provided with means for setting and storing different transmission start times, and each set value must be managed and updated one by one, resulting in high costs.

  The present invention provides a measurement data transmission control device for a sensor terminal in which each sensor terminal controls the measurement data transmission start time autonomously and distributedly at low cost and can avoid congestion due to concentration of measurement data signals. With the goal.

  The present invention provides a measurement data transmission control device of a sensor terminal that performs control to transmit measurement data measured by a sensor terminal to a data center at a predetermined transmission start time, and performs a hash function calculation by inputting a unique numerical value of the sensor terminal. A delay time calculating means for outputting a delay time according to the generated hash value, and a transmission start time for performing a control to delay the transmission start time of the measurement data of the sensor terminal by the delay time output from the delay time calculating means Control means.

  Here, the unique numerical value of the sensor terminal is uniquely set to the serial number uniquely assigned to the sensor terminal, or the MAC address when the sensor terminal is a wireless terminal, or the area where the sensor terminal is installed. It is a region number.

  The delay time calculation means is set uniquely as the unique numerical value of the sensor terminal, the serial number uniquely assigned to the sensor terminal, the MAC address when the sensor terminal is a wireless terminal, and the area where the sensor terminal is installed The hash function calculation may be performed by combining at least two of the area numbers. The delay time calculation means may include a variable holding unit that holds a variable used for the hash function calculation, and the variable may be set based on information transmitted from the data center.

  The transmission start time control means may be configured to set a predetermined transmission start time based on information transmitted from the data center.

  According to the present invention, the delay time is calculated by a hash function calculation using a unique numerical value possessed by each sensor terminal, and each sensor terminal can control the transmission start time of measurement data in an autonomous and distributed manner. Thereby, it is not necessary to individually manage the transmission start time of each sensor terminal, and congestion due to concentration of measurement data signals can be avoided at low cost.

(First embodiment)
FIG. 1 shows a first embodiment of the present invention. In the figure, the measurement unit 11 of the sensor terminal measures an object using a predetermined measurement function, and stores the obtained measurement data in the measurement data holding unit 12. The communication unit 13 reads the measurement data from the measurement data holding unit 12, converts it into a measurement data signal, and transmits it at a timing according to the transmission control signal output from the transmission start time control means 30.

  In the present embodiment, in order to generate a transmission control signal to be given to the communication unit 13, a delay time calculation unit 20A and a transmission start time control unit 30 are provided. The delay time calculation means 20A includes a terminal number holding unit 21 and a hash function calculation unit 22 that hold a terminal number as a unique number of the sensor terminal. As the terminal number, for example, there is a serial number uniquely assigned to the sensor terminal, or a MAC address when the sensor terminal is a wireless terminal. The hash function calculation unit 22 inputs the terminal number from the terminal number holding unit 21, performs a predetermined hash function calculation, calculates a hash value, and outputs it as a delay time. In the hash function operation, a hash value (pseudo-random number) is calculated by performing a logical operation such as logical sum / logical product, four arithmetic operations, a remainder operation, etc. by combining a numerical value of each digit of the terminal number and a predetermined constant. . On the other hand, if the time length of the measurement data signal is, for example, in the order of milliseconds, the delay time may be sufficiently longer than that, for example, in the order of seconds. Therefore, when the hash value cannot be used as it is as the delay time, a predetermined conversion process is performed.

  The transmission start time control unit 30 adds a transmission start time holding unit 31 that holds a predetermined transmission start time, and adds the delay time output from the delay time calculation unit 20A to the transmission start time, thereby correcting the transmission start time. Is added, the time measuring unit 33 that measures the time, the time of the time measuring unit 33 is compared with the corrected transmission start time, and the transmission control signal is output to the communication unit 13 at the timing when they match. And a comparison unit 34.

  In the present embodiment, instead of transmitting the measurement data signal at the transmission start time held in the transmission start time holding unit 31, the measurement data signal is transmitted at the transmission start time with the hash value calculated from the terminal number added as a delay time. Is sent. On the other hand, since each of the plurality of sensor terminals has a unique terminal number, the transmission timing of the measurement data signal transmitted from each sensor terminal is random. Therefore, in the past, as shown in FIG. 2 (1), the measurement data concentrated on the data center (FIG. 6: 54) and overloaded, but by performing load distribution as in this embodiment, As shown in FIG. 2 (2), the processing amount of the data center can be leveled.

(Second Embodiment)
FIG. 3 shows a second embodiment of the present invention. The feature of this embodiment is that the area number where the sensor terminal is installed is used as the unique number of the sensor terminal. The delay time calculation unit 20B of the present embodiment includes an area number holding unit 23 instead of the terminal number holding unit 21 of the first embodiment. Other configurations and operations are the same as those in the first embodiment.

(Third embodiment)
FIG. 4 shows a third embodiment of the present invention. The feature of this embodiment is that both the terminal number used in the first embodiment and the area number used in the second embodiment are used as the unique numbers of the sensor terminals, and both numbers are stored in the hash function calculation unit 22. They are used as variables. The delay time calculation means 20C of the present embodiment includes the terminal number holding unit 21 of the first embodiment and the area number holding unit 23 of the second embodiment, and outputs the terminal number and area number to be output respectively as a hash function calculation unit. 22 is input. Other configurations and operations are the same as those in the first embodiment and the second embodiment.

(Fourth embodiment)
FIG. 5 shows a fourth embodiment of the present invention. In addition to the terminal number holding unit 21 and the area number holding unit 23, the delay time calculating unit 20D according to the present embodiment includes a variable holding unit 24 that holds a variable to be given to the hash function calculation unit 22, and the communication unit 13 receives the variable holding unit 24. A feature is that the variable of the variable holding unit 24 is rewritten in accordance with information from the data center (FIG. 6: 54). The delay time calculation unit 20D may include only one of the terminal number holding unit 21 and the area number holding unit 23. Moreover, it is good also as a structure which rewrites the transmission start time of the transmission start time holding | maintenance part 31 of the transmission start time control means 30 according to the information from the data center (FIG. 6:54) received by the communication part 13. FIG.

The figure which shows the structure of the 1st Embodiment of this invention. The figure explaining the effect of this invention. The figure which shows the structure of the 2nd Embodiment of this invention. The figure which shows the structure of the 3rd Embodiment of this invention. The figure which shows the structure of the 4th Embodiment of this invention. A configuration example of a wide area telemetry system is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Measurement part 12 Measurement data holding part 13 Communication part 20A, 20B, 20C, 20D Delay time calculation means 21 Terminal number holding part 22 Hash function calculating part 23 Area number holding part 24 Variable holding part 30 Transmission start time control means 31 Transmission start Time holding unit 32 Addition unit 33 Timekeeping unit 34 Comparison unit 51 Sensor terminal 52 Wireless base station 53 Relay station 54 Data center

Claims (7)

In the measurement data transmission control device of the sensor terminal that performs control to transmit the measurement data measured by the sensor terminal to the data center at a predetermined transmission start time,
A delay time calculating means for inputting a specific numerical value of the sensor terminal to perform a hash function operation and outputting a delay time according to the generated hash value;
A measurement start transmission control device for a sensor terminal, comprising: a transmission start time control means for performing a control to delay the transmission start time of the measurement data of the sensor terminal by a delay time output from the delay time calculation means . In the measurement data transmission control device of the sensor terminal according to claim 1,
The measurement data transmission control device for a sensor terminal, wherein the unique numerical value of the sensor terminal is a serial number uniquely assigned to the sensor terminal. In the measurement data transmission control device of the sensor terminal according to claim 1,
The measurement data transmission control apparatus for a sensor terminal, wherein the unique numerical value of the sensor terminal is a MAC address when the sensor terminal is a wireless terminal. In the measurement data transmission control device of the sensor terminal according to claim 1,
The measurement data transmission control device of a sensor terminal, wherein the unique numerical value of the sensor terminal is an area number uniquely set in an area where the sensor terminal is installed. In the measurement data transmission control device of the sensor terminal according to claim 1,
The delay time calculation means includes a serial number uniquely assigned to the sensor terminal as a unique numerical value of the sensor terminal, a MAC address when the sensor terminal is a wireless terminal, and the sensor terminal is installed. A measurement data transmission control apparatus for a sensor terminal, characterized in that a hash function calculation is performed by combining at least two area numbers uniquely set for each area. In the measurement data transmission control device of the sensor terminal according to claim 1,
The delay time calculating unit includes a variable holding unit that holds a variable used for the hash function calculation, and the variable terminal is configured to set the variable based on information transmitted from the data center. Measurement data transmission control device. In the measurement data transmission control device of the sensor terminal according to claim 1,
The measurement data transmission control device for a sensor terminal, wherein the transmission start time control means is configured to set the predetermined transmission start time based on information transmitted from the data center.

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