Power saving in a contention and polling system communication system

• US 6,346,873 B1
• Filed: 01/02/1997
• Issued: 02/12/2002
• Est. Priority Date: 06/01/1992
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tatsumi, Eisaku, Sunakawa, Shinichi, Shimada, Kazutoshi, Suzuki, Noriyuki, Nagasaki, Katsuhiko
• Primary Examiner(s): ZIMMERMAN, BRIAN A
• Application Number:
  US08/775,883
• Time in Patent Office: 1,867 Days
• Field of Search: 340/825.07, 340/825.06, 340/825.54, 340/825.08, 340/10.1, 340/7.32, 340/3.41, 455/343, 455/38.3, 370/311
• US Class Current: 340/3.41
• CPC Class Codes: H04Q 2213/1308 Power supply
• CPC Class Codes: H04Q 2213/13092 Scanning of subscriber lines, monitoring
• CPC Class Codes: H04Q 2213/13103 Memory
• CPC Class Codes: H04Q 2213/13106 Microprocessor, CPU
• CPC Class Codes: H04Q 2213/13141 Hunting for free outlet, circuit or channel
• CPC Class Codes: H04Q 2213/13204 Protocols
• CPC Class Codes: H04Q 2213/13242 Broadcast, diffusion, multicast, point-to-multipoint (1 : N)
• CPC Class Codes: H04Q 3/0016 Arrangements providing connection between exchanges

Abstract

A parent node transmits a third specific message to child nodes as a broadcast message if a first specific message indicating the start of the child node collides with another message so that normal receiving cannot be performed. Then, the parent node sequentially transmits second specific messages to each child node and then receives responses to recognize the states of the children nodes. The parent node transmits a specific message indicating a realization of a sleeping state as a broadcast message to the children nodes, followed by transmitting a specific message when data to be transmitted from the child node has been generated. The parent node cancels the sleeping state when it receives the specific message.

Claims

1. A parent node for use in a communication system that has a parent node and a plurality of child nodes, the plurality of child nodes being able to communicate in a first mode in which a child node can communicate with said parent node when said child node receives a first message to recognize existence of a transmission request to be transmitted from said parent node, said parent node comprising:

transmission means for transmitting a second message that said parent node announces to said child nodes that the parent node is saving power;

power saving means for performing the power saving when the second message is transmitted; and

communication means for communicating with said child node in a second mode in which said child node can communicate regardless of not having received the first message when said parent node is saving power,

in response to said parent node communicating with said child node in the second mode, other child nodes return to the first communication mode.

2. A parent node according to claim 1, wherein said child node transmits a third message to indicate a transmission request to said parent node when said parent node is saving power, and said communication means communicates with said child node when the third message is received.

3. A parent node according to claim 2, wherein said parent node cancels the power saving when the third message is received.

4. A parent node according to claim 2, wherein said child node saves power when it receives the second message, and said parent node transmits a fourth message that said child node should cancel the power saving when the third message is received.

5. A parent node according to claim 4, wherein the fourth message is transmitted to each of said plurality of children nodes.

6. A parent node according to claim 1, wherein said parent node performs the power saving by cutting a supply of electric power to a portion of circuits of said parent node.

7. A parent node according to claim 1, wherein the second message is transmitted in a broadcast to each of said plurality of children nodes.

8. A control method of a parent node for use in a communication system that has a parent node and a plurality of child nodes, the plurality of child nodes being able to communicate in a first mode in which a child node can communicate with the parent node when the child node receives a first message to recognize existence of a transmission request to be transmitted from the parent node, said control method comprising:

a transmission step for transmitting a second message that the parent node announces to the child nodes that the parent node is saving power;

a power saving step for performing the power saving when the second message is transmitted; and

a communication step for communicating with the child node in a second mode in which the child node can communicate regardless of not having received the first message when the parent node is saving power,

in response to said parent node communicating with said child node in the second mode, other child nodes return to the first communication mode.

9. A control method according to claim 8, wherein the child node transmits a third message to indicate a transmission request to the parent node when the parent node is saving power, and said communication step causes communication with the child node when the third message is received.

10. A control method according to claim 8, wherein the parent node performs the power saving by cutting a supply of electric power to a portion of circuits of the parent node.

11. A control method according to claim 8, wherein the second message is transmitted in a broadcast to each of the plurality of children nodes.

12. A control method according to claim 9, wherein the parent node cancels the power saving when the third message is received.

13. A control method according to claim 9, wherein the child node saves power when it receives the second message, and the parent node transmits a fourth message that the child node should cancel the power saving when the third message is received.

14. A control method according to claim 13, wherein the fourth message is transmitted to each of the plurality of children nodes.

15. A communication control apparatus in a communication system having a communication control apparatus and a communication apparatus, the communication control apparatus comprising:

a polling communication means for making a polling communication with said communication apparatus in a polling communication mode;

a contention communication means for making a contention communication with said communication apparatus in a contention communication mode; and

a control means for ending the contention communication mode of other communication apparatuses when starting communication with said communication apparatus while a plurality of communication apparatuses stand by in the contention communication mode.

16. A communication apparatus in a communication system having a communication control apparatus and the communication apparatus, the communication apparatus comprising:

polling communication means for making a polling communication with said communication control apparatus in a polling communication mode;

contention communication means for making a contention communication with said communication control apparatus in a contention communication mode; and

control means for controlling so as to end the contention communication mode when another communication apparatus starts communication with the communication control apparatus while standing by in the contention communication mode.

17. A communication system having a parent node and a plurality of children nodes, the plurality of children nodes being able to communicate in a first mode in which a child node can communicate with said parent node when said child node receives a first message to recognize existence of a transmission request to be transmitted from said parent node, comprising:

power saving means for said parent node to save power when said parent node transmits a second message to said children nodes in order to announce that said parent node is saving power; and

communication means for communicating in a second mode in which said child node can transmit data to said parent node regardless of not having received the first message, when data to be transmitted to the parent node are generated, while said parent node is saving power by said power saving means,

in response to said parent node communicating with said child node in the second mode, other children nodes return to the first communication mode.

18. A communication system according to claim 17, wherein said child node transmits a third message to indicate a transmission request to said parent node when said parent node is saving power.

19. A communication system according to claim 18, wherein said parent node cancels the power saving when said parent node receives the third message.

20. A communication system according to claim 17, wherein said parent node performs the power saving by cutting a supply of electric power to a portion of circuits of said parent node.

21. A communication system according to claim 17, wherein the second message is transmitted in a broadcast to each of said plurality of children nodes.

22. A communication system according to claim 17, wherein each of said plurality of children nodes saves power when there are no data to be transmitted to said parent node in a predetermined time period, and cancels the power saving when data to be transmitted to said parent node is generated.

23. A communication system according to claim 17, wherein each of said plurality of children nodes saves power when there are no data to be transmitted from said parent node in a predetermined time period, and cancels the power saving when a predetermined message is received from said parent node.

24. A communication system according to claim 17, wherein said child node saves power by cutting a supply of electric power to a portion of circuits of said child node.

25. A communication system according to claim 18, wherein said parent node transmits a fourth message that said child node should cancel the power saving when the third message is received.

26. A communication system according to claim 25, wherein the fourth message is transmitted to each of said plurality of children nodes.

27. A control method for use in a communication system having a parent node and a plurality of child nodes, the plurality of child nodes being able to communicate in a first mode in which a child node can communicate with the parent node when the child node receives a first message to recognize existence of a transmission request to be transmitted from the parent node, comprising:

a power saving step for causing the parent node to save power when the parent node transmits a second message to the child nodes in order to announce that the parent node is saving power; and

a communication step causing communication in a second mode in which the child node can transmit data to the parent node regardless of not having received the first message when data to be transmitted to the parent node is generated while the parent node is saving power,

in response to said parent node communicating with said child node in the second mode, other child nodes return to the first communication mode.

28. A control method according to claim 27, wherein the child node transmits a third message to indicate a transmission request when the parent node is saving power.

29. A control method according to claim 28, wherein the parent node cancels the power saving when the third message is received.

30. A control method according to claim 27, wherein the parent node saves power by cutting a supply of electric power to a portion of circuits of the parent node.

31. A control method according to claim 27, wherein the second message is transmitted in a broadcast to each of the plurality of children nodes.

32. A control method according to claim 27, wherein each of the plurality of children nodes saves power when there are no data to be transmitted to the parent node in a predetermined time period, and cancels the power saving when data to be transmitted to said parent node is generated.

33. A control method according to claim 27, wherein each of the plurality of children nodes saves power when there are no data to be transmitted from the parent node in a predetermined time period, and cancels the power saving when a predetermined message is received from the parent node.

34. A control method according to claim 27, wherein the child node saves power by cutting a supply of electric power to a portion of circuits of the child node.

35. A control method according to claim 28, wherein the parent node transmits a fourth message that the child node should cancel the power saving when the third message is received.

36. A control method according to claim 35, wherein the fourth message is transmitted to each of the plurality of children nodes.

37. A child node for use in a communication system that has a parent node and a plurality of child nodes, said child node being able to communicate in a first mode in which a child nodes can communicate with said parent node when said child node receives a first message to recognize existence of a transmission request to be transmitted from said parent node, said child node comprising:

recognition means for recognizing that said parent node is saving power corresponding to said child node receiving a second message transmitted by said parent node to announce that said parent node is saving power; and

communication means for communicating in a second mode in which said child node can transmit data to said parent node regardless of not having received the first message when data to be transmitted to said parent node is generated while said parent node is saving power and while it is recognized by said recognition means that the parent node is saving power,

in response to said parent node communicating with said child node in the second mode, other child nodes return to the first communication mode.

38. A child node according to claim 37, wherein said child node transmits a third message to indicate a transmission request to said parent node when said parent node is saving power.

39. A child node according to claim 38, wherein said parent node performs the power saving when said parent node transmits the second message to said child node, and the third message is also a message for said parent node to cancel the power saving.

40. A child node according to claim 37, wherein the second message is transmitted in a broadcast to each of said plurality of children nodes.

41. A child node according to claim 37, wherein said child node saves power when there are no data to be transmitted to said parent node in a predetermined time period, and cancels the power saving when data to be transmitted to said parent node is generated.

42. A child node according to claim 37, wherein said child node saves power when there are no data to be transmitted from said parent node in a predetermined time period, and cancels the power saving when a predetermined message is received from said parent node.

43. A child node according to claim 37, wherein said parent node performs the power saving by cutting a supply of electric power to a portion of circuits of said parent node.

44. A child node according to claim 38, wherein said child node saves power when it receives the second message, and said parent node transmits a fourth message that said child node should cancel the power saving when the third message is received, and said child node cancels the power saving when the fourth message is received.

45. A control method for use with a child node in a communication system that has a parent node and a plurality of child nodes, the child node being able to communicate in a first mode in which the child node can communicate with the parent node when the child node receives a first message to recognize existence of a transmission request to be transmitted from the parent node, said control method comprising:

a recognition step for recognizing that the parent node is saving power corresponding to the child node receiving a second message transmitted by the parent node to announce that the parent node is saving power; and

communication step for communicating in a second mode in which the child node can transmit data to the parent node regardless of not having received the first message when data to be transmitted to the parent node is generated while the parent node is saving power and while it is recognized in said recognition step that the parent node is saving power,

in response to said parent node communicating with said child node in the second mode, other child nodes return to the first communication mode.

46. A control method according to claim 45, wherein the child node transmits a third message to indicate a transmission request to the parent node when the parent node is saving power.

47. A control method according to claim 45, wherein the parent node performs the power saving when the parent node transmits the second message to the child node, and the third message is also a message for the parent node to cancel the power saving.

48. A control method according to claim 45, wherein the second message is transmitted in a broadcast to each of the plurality of children nodes.

49. A control method according to claim 45, wherein the child node saves power when there are no data to be transmitted to the parent node in a predetermined time period, and cancels the power saving when data to be transmitted to the parent node is generated.

50. A control method according to claim 45, wherein the child node saves power when there are no data to be transmitted from the parent node in a predetermined time period, and cancels the power saving when a predetermined message is received from the parent node.

51. A control method according to claim 45, wherein the parent node performs the power saving by cutting a supply of electric power to a portion of circuits of the parent node.

52. A control method according to claim 46, wherein the child node saves power when it receives the second message, and the parent node transmits a fourth message that the child node should cancel the power saving when the third message is received, and the child node cancels the power saving when the fourth message is received.