CONTROL APPARATUS, CONTROL METHOD, COMMUNICATION SYSTEM COMPRISING CONTROL APPARATUS AND ONE OR MORE TERMINALS

• US 20080144506A1
• Filed: 12/07/2007
• Published: 06/19/2008
• Est. Priority Date: 12/19/2006
• Status: Abandoned Application

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kanda, Tetsuo
• Application Number:
  US11/952,762
• Publication Number:
  US 20080144506A1
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: G08C 15/00 Arrangements characterised by the use of multiplexing for the transmission of a plurality of signals over a common path

Abstract

In a radio communication system including terminals that access a control apparatus by a random access method, the number of collisions between data transmitted from the terminals is reduced. A control method for the control apparatus capable of communicating with at least one terminal located within a communicable range includes transmitting information designating a communication period in which the terminal transmits data to the control apparatus, changing a transmission range over which the information is transmitted, and transmitting, after transmitting first information designating a first communication period over a first transmission range, second information designating a second communication period which differs from the first communication period over a changed second transmission range.

Claims

1. A control apparatus capable of communicating with a terminal, the control apparatus comprising:

a transmitting unit configured to transmit information designating a communication period in which the terminal transmits data to the control apparatus;

a changing unit configured to change a transmission range over which the information is transmitted; and

a control unit configured to transmit, after transmitting first information designating a first communication period over a first transmission range, second information designating a second communication period which differs from the first communication period over a second transmission range changed by the changing unit.

2. The control apparatus according to claim 1, wherein the changing unit changes the transmission range over which the information is transmitted by changing transmission power used to transmit the information.

3. The control apparatus according to claim 1, further comprising an identifying unit configured to identify any terminals located within a range communicable with the control apparatus,

wherein when there are a plurality of terminals identified, the control unit executes control to transmit, after transmitting first information designating a first communication period over a first transmission range, second information designating a second communication period that differs from the first communication period over a second transmission range changed by the changing unit.

4. The control apparatus according to claim 1, wherein the control unit executes a first process of transmitting the information over a communicable range and a second process of transmitting information, which designates different transmission periods, to a plurality of communication ranges included within the communicable range.

5. The control apparatus according to claim 4, further comprising an identifying unit configured to identify any terminals located within a range communicable with the control apparatus,

wherein the control unit executes the first process or the second process depending on how many terminals are identified.

6. The control apparatus according to claim 5, wherein the control unit executes the first process when a single terminal located within the communicable range is identified.

7. The control apparatus according to claim 5, wherein a plurality of terminals located within the range communicable with the control apparatus are identified by detecting a collision between data sent from the terminals, and

the control unit executes the second process when a plurality of terminals located within the communicable range are identified.

8. A method for a control apparatus capable of communicating with a terminal, the method comprising:

transmitting information designating a communication period in which the terminal transmits data to the control apparatus;

changing a transmission range over which the information is transmitted; and

transmitting, after transmitting first information designating a first communication period over a first transmission range, second information designating a second communication period that differs from the first communication period over a changed second transmission range.

9. The method according to claim 8, wherein the transmission range over which the information is transmitted is changed by changing transmission power used to transmit the information.

10. The method according to claim 8, further comprising:

identifying any terminals located within a range communicable with the control apparatus,

wherein when a plurality of terminals located within the range communicable with the control apparatus are identified, executing control to transmit, after transmitting first information designating a first communication period over a first transmission range, second information designating a second communication period that differs from the first communication period over a changed second transmission range.

11. The method according to claim 8, further comprising executing a first process of transmitting the information over a communicable range and a second process of transmitting information, which designates different transmission periods, to a plurality of communication ranges included within the communicable range.

12. The method according to claim 11, further comprising:

identifying any terminals located within a range communicable with the control apparatus; and

executing the first process or the second process depending on how many terminals are identified.

13. The method according to claim 12, further comprising:

executing the first process when a single terminal is identified as being located within the range communicable with the control apparatus.

14. The method according to claim 12, further comprising:

identifying that a plurality of terminals are located within the range communicable with the control apparatus by detecting a collision between data sent from the terminals located within the range communicable with the control apparatus; and

executing the second process when a plurality of terminals are located within the communicable range.

15. A communication system, the communication system comprising:

a control apparatus; and

a terminal, wherein the terminal transmits data to the control apparatus in a communication period that is designated by information transmitted from the control apparatus,

wherein the control apparatus comprises;

a changing unit configured to change a transmission range over which the information is transmitted; and

a control unit configured to transmit, after transmitting first information designating a first communication period over a first transmission range, second information designating a second communication period that differs from the first communication period over a second transmission range changed by the changing unit.

16. The communication system according to claim 15, wherein the changing unit changes the transmission range over which the information is transmitted by changing transmission power used to transmit the information.

17. The communication system according to claim 15, wherein the control apparatus further comprises an identifying unit configured to identify any terminals located within a range communicable with the control apparatus,

wherein when a plurality of terminals are identified, the control unit executes control to transmit, after transmitting first information designating a first communication period over a first transmission range, second information designating a second communication period that differs from the first communication period over a second transmission range changed by the changing unit.

18. The communication system according to claim 15, wherein the control unit executes a first process of transmitting the information over a communicable range and a second process of transmitting information, which designates different transmission periods, to a plurality of communication ranges included within the communicable range.

19. The communication system according to claim 18, wherein the control apparatus further comprises an identifying unit configured to identify any terminals located within a range communicable with the control apparatus,

wherein the control unit executes the first process or the second process depending on how many terminals are identified.

20. The communication system according to claim 19, wherein the control unit executes the first process when a single terminal located within the communicable range is identified.

21. The communication system according to claim 19, wherein a plurality of terminals located within the range communicable with the control apparatus are identified by detecting a collision between data sent from the terminals, and

wherein the control unit executes the second process when a plurality of terminals located within the communicable range are identified.

22. A computer-readable storage medium storing a program for causing a control apparatus to communicate with a terminal, the program comprising:

transmitting information designating a communication period in which the terminal transmits data to the control apparatus;

changing a transmission range over which the information is transmitted; and

transmitting, after transmitting first information designating a first communication period over a first transmission range, second information designating a second communication period that differs from the first communication period over a second transmission range.