Data collection system and data collection method

• US 20050063326A1
• Filed: 09/16/2004
• Published: 03/24/2005
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Isoyama, Kazuhiko, Kawasaki, Daisuke, Ohkuma, Takahiro
• Granted Patent: US 7,782,766 B2
• Time in Patent Office: Days
• US Class Current: 370/310
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

The present invention relates to a data collection system and a data collection method in a sensor network, enabling sensor modules to consume lower amounts of power. The base station transmits data collection request signals to one or more sensor modules which are lower than the base station by 1 in a tree structure. Each sensor module which has received the data collection request signal transfers the signal to one or more sensor modules which are lower than the module by 1. The base station regards the transfer of the signal as ACK for the data collection request signal transmitted therefrom to the sensor module which is lower than the base station by 1. The transmission of a data collection acknowledgement signal starts from a sensor module at the low-order end. When a sensor module receives the data collection acknowledgement signal from a downstream sensor module which is lower than the module by 1, the module transmits the signal to an upstream sensor module which is higher than the module by 1. The downstream sensor module regards the transmission of the signal as ACK for the data collection acknowledgement signal transmitted therefrom, and enters standby mode. In this manner, the sensor modules enter standby mode in sequence starting from the sensor module at the low-order end. Thereby, it is possible to achieve reductions in the frequency of signal transmission while maintaining reliable data communication. Thus, each module consumes lower amounts of power.

Claims

1. A data collection system comprising a base station, at least one upstream module being directly subordinate to the base station, and at least one downstream module being directly subordinate to the upstream module, which are connected via a network, wherein:

the base station includes;

a section for transmitting a first data collection request signal containing ID of the base station to the upstream module;

a section for receiving a second data collection acknowledgement signal from the upstream module, the second data collection acknowledgement signal containing ID of the upstream module and measured data obtained by each module; and

a section for compiling the measured data;

the upstream module includes;

a section for receiving the first data collection request signal from the base station;

a section for transmitting a second data collection request signal containing the ID of the upstream module to the downstream module;

a section for obtaining measured data through a sensor; and

a section for transmitting the measured data to the base station as the second data collection acknowledgement signal;

the downstream module includes;

a section for receiving the second data collection request signal from the upstream module;

a section for obtaining measured data through a sensor; and

a section for transmitting the measured data to the upstream module as a first data collection acknowledgement signal;

the second data collection request signal is transmitted to the base station simultaneously with the transmission of the second data collection request signal to the downstream module, and the base station regards the second data collection request signal as ACK for the first data collection request signal;

when receiving the first data collection acknowledgement signal, the upstream module regards the first data collection acknowledgement signal as ACK for the second data collection request signal; and

the second data collection acknowledgement signal is transmitted to the downstream module simultaneously with the transmission of the second data collection acknowledgement signal to the base station, and the downstream module regards the second data collection acknowledgement signal as ACK for the first data collection acknowledgement signal.

2. The data collection system claimed in claim 1, wherein each of the base station, upstream module and downstream module retains routing information.

3. The data collection system claimed in claim 1, wherein each of the base station, upstream module and downstream module is provided with a receive wait timer.

4. The data collection system claimed in claim 1, wherein each of the base station, upstream module and downstream module retains routing information, and is provided with a receive wait timer.

5. The data collection system claimed in claim 3, wherein in the case where a time-out occurs when the base station waits for ACK from the upstream module which is directly subordinate to the base station as a reply to the first data collection request signal, the base station retransmits the first data collection request signal to the upstream module.

6. The data collection system claimed in claim 4, wherein in the case where a time-out occurs when the base station waits for ACK from the upstream module which is directly subordinate to the base station as a reply to the first data collection request signal, the base station retransmits the first data collection request signal to the upstream module.

7. The data collection system claimed in claim 3, wherein in the case where a time-out occurs when the base station waits for the second data collection acknowledgement signal from the upstream module, the base station sends a data collection acknowledgement signal retransmission request to the upstream module.

8. The data collection system claimed in claim 4, wherein in the case where a time-out occurs when the base station waits for the second data collection acknowledgement signal from the upstream module, the base station sends a data collection acknowledgement signal retransmission request to the upstream module.

9. The data collection system claimed in claim 3, wherein in the case where a time-out occurs when the upstream module waits for ACK from the downstream module as a reply to the second data collection request signal, the upstream module retransmits the second data collection request signal to the downstream module.

10. The data collection system claimed in claim 4, wherein in the case where a time-out occurs when the upstream module waits for ACK from the downstream module as a reply to the second data collection request signal, the upstream module retransmits the second data collection request signal to the downstream module.

11. The data collection system claimed in claim 3, wherein in the case where a time-out occurs when the upstream module waits for the first data collection acknowledgement signal from the downstream module, the upstream module sends a data collection acknowledgement signal retransmission request to the downstream module.

12. The data collection system claimed in claim 4, wherein in the case where a time-out occurs when the upstream module waits for the first data collection acknowledgement signal from the downstream module, the upstream module sends a data collection acknowledgement signal retransmission request to the downstream module.

13. The data collection system claimed in claim 1, wherein when the upstream module and the downstream module complete prescribed process, the upstream module and the downstream module enter standby mode.

14. The data collection system claimed in claim 2, wherein when the upstream module and the downstream module complete prescribed process, the upstream module and the downstream module enter standby mode.

15. The data collection system claimed in claim 3, wherein when the upstream module and the downstream module complete prescribed process, the upstream module and the downstream module enter standby mode.

16. The data collection system claimed in claim 4, wherein when the upstream module and the downstream module complete prescribed process, the upstream module and the downstream module enter standby mode.

17. The data collection system claimed in claim 3, wherein in the case where a time-out occurs when the upstream module waits for ACK from the base station as a reply to the second data collection acknowledgement signal, the upstream module enters standby mode.

18. The data collection system claimed in claim 4, wherein in the case where a time-out occurs when the upstream module waits for ACK from the base station as a reply to the second data collection acknowledgement signal, the upstream module enters standby mode.

19. The data collection system claimed in claim 3, wherein when the upstream module does not receive the data collection acknowledgement signal retransmission request from the base station for a fixed period of time, a time-out occurs, and the upstream module enters standby mode.

20. The data collection system claimed in claim 4, wherein when the upstream module does not receive the data collection acknowledgement signal retransmission request from the base station for a fixed period of time, a time-out occurs, and the upstream module enters standby mode.

21. The data collection system claimed in claim 3, wherein:

in the case where a time-out occurs when the base station waits for ACK from the upstream module as a reply to the first data collection request signal, the base station retransmits the first data collection request signal to the upstream module;

in the case where a time-out occurs when the base station waits for the second data collection acknowledgement signal from the upstream module, the base station sends a data collection acknowledgement signal retransmission request to the upstream module;

in the case where a time-out occurs when the upstream module waits for ACK from the downstream module as a reply to the second data collection request signal, the upstream module retransmits the second data collection request signal to the downstream module;

in the case where a time-out occurs when the upstream module waits for the first data collection acknowledgement signal from the downstream module, the upstream module sends a data collection acknowledgement signal retransmission request to the downstream module;

when the upstream module and the downstream module complete prescribed process, the upstream module and the downstream module enter standby mode;

in the case where a time-out occurs when the upstream module waits for ACK from the base station as a reply to the second data collection acknowledgement signal, the upstream module enters standby mode; and

when the upstream module does not receive the data collection acknowledgement signal retransmission request from the base station for a fixed period of time, a time-out occurs, and the upstream module enters standby mode.

22. The data collection system claimed in claim 4, wherein:

in the case where a time-out occurs when the base station waits for ACK from the upstream module as a reply to the first data collection request signal, the base station retransmits the first data collection request signal to the upstream module;

in the case where a time-out occurs when the base station waits for the second data collection acknowledgement signal from the upstream module, the base station sends a data collection acknowledgement signal retransmission request to the upstream module;

in the case where a time-out occurs when the upstream module waits for ACK from the downstream module as a reply to the second data collection request signal, the upstream module retransmits the second data collection request signal to the downstream module;

in the case where a time-out occurs when the upstream module waits for the first data collection acknowledgement signal from the downstream module, the upstream module sends a data collection acknowledgement signal retransmission request to the downstream module;

when the upstream module and the downstream module complete prescribed process, the upstream module and the downstream module enter standby mode;

in the case where a time-out occurs when the upstream module waits for ACK from the base station as a reply to the second data collection acknowledgement signal, the upstream module enters standby mode; and

when the upstream module does not receive the data collection acknowledgement signal retransmission request from the base station for a fixed period of time, a time-out occurs, and the upstream module enters standby mode.

23. The data collection system claimed in claim 1, wherein the base station explicitly indicates the completion of data collecting by transmitting a data collection completion signal to the upstream module which is directly subordinate to the base station so that the upstream module enters standby mode immediately after the base station has completed data collecting.

24. The data collection system claimed in claim 1, wherein the network have a structure selected from a tree structure, a linear structure and a ring structure.

25. A data collection system for a network capable of broadcasting, comprising three or more multiprocessors which are connected through a bus, wherein:

a first multiprocessor includes a section for outputting a first processing request signal to a second multiprocessor;

the second multiprocessor includes a section for performing prescribed process, and outputting a second processing request signal to a third multiprocessor; and

the first multiprocessor regards the second processing request signal as ACK for the first processing request signal.

26. A data collection method for a data collection system comprising a base station, at least one upstream module being directly subordinate to the base station, and at least one downstream module being directly subordinate to the upstream module, which are connected via a network, comprising:

a step at which the base station transmits a first data collection request signal containing ID of the base station to the upstream module;

a step at which the upstream module receives the first data collection request signal, and verifies whether ID of the source of the first data collection request signal contained in the signal matches ID of the base station from routing information retained by the upstream module;

a step at which the upstream module starts performing measurements to obtain measured data triggered by the first data collection request signal, and transmits a second data collection request signal containing ID of the upstream module to the downstream module;

a step at which the second data collection request signal is transmitted to the base station simultaneously with the transmission of the second data collection request signal to the downstream module, and the base station regards the second data collection request signal as ACK for the first data collection request signal;

a step at which, on receipt of the second data collection request signal, the downstream module verifies whether ID of the source of the second data collection request signal contained in the signal matches ID of the upstream module from routing information retained by the downstream module, and starts performing measurements to obtain measured data;

a step at which, after completing the measurements, the downstream module sends the upstream module a first data collection acknowledgement signal containing ID of the downstream module and the measured data obtained by the downstream module;

a step at which, when receiving the first data collection acknowledgement signal from the downstream module based on the routing information, the upstream module regards the first data collection acknowledgement signal as ACK for the second data collection request signal;

a step at which the upstream module produces a second data collection acknowledgement signal containing the measured data obtained by the downstream module in addition to the measured data obtained by the upstream module and the ID of the upstream module, and transmits the second data collection acknowledgement signal to the base station;

a step at which, simultaneously with the transmission of the second data collection acknowledgement signal to the base station, the downstream module receives the second data collection acknowledgement signal; and

a step at which, having received the second data collection acknowledgement signal, the downstream module regards the second data collection acknowledgement signal as ACK for the first data collection acknowledgement signal, and enters standby mode to reduce electric power consumption.

27. The data collection method claimed in claim 26, wherein each of the base station, upstream module and downstream module is provided with a receive wait timer.

28. The data collection method claimed in claim 27, wherein in the case where a time-out occurs when the base station waits for ACK from the upstream module which is directly subordinate to the base station as a reply to the first data collection request signal, the base station retransmits the first data collection request signal to the upstream module.

29. The data collection method claimed in claim 27, wherein in the case where a time-out occurs when the base station waits for the second data collection acknowledgement signal from the upstream module, the base station sends a data collection acknowledgement signal retransmission request to the upstream module.

30. The data collection method claimed in claim 27, wherein in the case where a time-out occurs when the upstream module waits for ACK from the downstream module as a reply to the second data collection request signal, the upstream module retransmits the second data collection request signal to the downstream module.

31. The data collection method claimed in claim 27, wherein in the case where a time-out occurs when the upstream module waits for the first data collection acknowledgement signal from the downstream module, the upstream module sends a data collection acknowledgement signal retransmission request to the downstream module.

32. The data collection method claimed in claim 26, wherein when the upstream module and the downstream module complete prescribed process, the upstream module and the downstream module enter standby mode.

33. The data collection method claimed in claim 27, wherein when the upstream module and the downstream module complete prescribed process, the upstream module and the downstream module enter standby mode.

34. The data collection method claimed in claim 27, wherein in the case where a time-out occurs when the upstream module waits for ACK from the base station as a reply to the second data collection acknowledgement signal, the upstream module enters standby mode.

35. The data collection method claimed in claim 27, wherein when the upstream module does not receive the data collection acknowledgement signal retransmission request from the base station for a fixed period of time, a time-out occurs, and the upstream module enters standby mode.

36. The data collection method claimed in claim 27, wherein:

in the case where a time-out occurs when the base station waits for ACK from the upstream module as a reply to the first data collection request signal, the base station retransmits the first data collection request signal to the upstream module;

in the case where a time-out occurs when the base station waits for the second data collection acknowledgement signal from the upstream module, the base station sends a data collection acknowledgement signal retransmission request to the upstream module;

in the case where a time-out occurs when the upstream module waits for ACK from the downstream module as a reply to the second data collection request signal, the upstream module retransmits the second data collection request signal to the downstream module;

in the case where a time-out occurs when the upstream module waits for the first data collection acknowledgement signal from the downstream module, the upstream module sends a data collection acknowledgement signal retransmission request to the downstream module;

when the upstream module and the downstream module complete prescribed process, the upstream module and the downstream module enter standby mode;

in the case where a time-out occurs when the upstream module waits for ACK from the base station as a reply to the second data collection acknowledgement signal, the upstream module enters standby mode; and

when the upstream module does not receive the data collection acknowledgement signal retransmission request from the base station for a fixed period of time, a time-out occurs, and the upstream module enters standby mode.

37. The data collection method claimed in claim 26, wherein the base station explicitly indicates the completion of data collecting by transmitting a data collection completion signal to the upstream module which is directly subordinate to the base station so that the upstream module enters standby mode immediately after the base station has completed data collecting.

38. The data collection method claimed in claim 26, wherein the network have a structure selected from a tree structure, a linear structure and a ring structure.

39. A data collection method for a network capable of broadcasting, which includes three or more multiprocessors and a bus for connecting the multiprocessors, comprising:

a step at which a first multiprocessor outputs a first processing request signal to a second multiprocessor;

a step at which the second multiprocessor performs prescribed process, and outputs a second processing request signal to a third multiprocessor; and

a step at which the first multiprocessor regards the second processing request signal as ACK for the first processing request signal.