Beaconless communication system

• US 20060133408A1
• Filed: 11/14/2005
• Published: 06/22/2006
• Est. Priority Date: 11/15/2004
• Status: Active Grant

• Current Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Inventors: Nogueira-Nine, Juan, Bohnke, Ralf
• Granted Patent: US 8,175,109 B2
• Time in Patent Office: Days
• US Class Current: 370/447
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The present invention relates to an energy efficient mechanism for establishing and maintaining a communication between nodes (A . . . F) in a wireless communication system. In particular, it relates to a distributed low power medium access control (MAC) mechanism for sharing the communication means in a wireless communication system. According to the present invention a destination node (A) listens to a communication channel periodically. For requesting services from the destination node (A), a wake-up signal (WU) is transmitted from a source node (B) to the destination node (A) via the communication channel, wherein the wake-up signal (WU) is formed by a preamble (WP) and an information for controlling the communication between nodes (A . . . F). The WU signal duration and content is adapted depending on the system operation context to reduce either idle times, power consumption, latency or network blocking (collision avoidance).

Claims

1. A communication method between nodes in a communication system, said communication system comprising at least two nodes (A, B), the method comprising the steps of:

listening to a communication channel by a destination node (A) periodically, wherein the listen duration is T_L and the listen periodicity is T_PL and T_L<

<

T_PL; and

transmitting a wake-up signal (WU) from a source node (B) to said destination node (A) via said communication channel;

characterised in that

said wake-up signal (WU) comprises a preamble (WP) and a control information (WD), wherein the duration of a signal block (SB) formed by said preamble (WP) and said control information (WD) is T_SB and 2×

T_SB<

T_L; and

in said communication system the communication between nodes (A . . . F) is controlled based on said control information (WD).

2. The communication method according to claim 1, wherein said communication system is a wireless communication system.

3. The communication method according to claim 1, wherein the listen duration is T_L and the listen periodicity is T_PL and 2T_L<

<

T_PL.

4. The communication method according to claim 1, wherein said communication system comprises a plurality of nodes (A . . . F) forming a network (1) and said control information (WD) indicates that said source node (B) wants to join said network (1).

5. The communication method according to claim 1, wherein said communication system comprises a plurality of nodes (A . . . F) forming a network (1) and said control information (WD) indicates that said source node (B) is still present in said network (1).

6. The communication method according to claim 1, wherein said communication system comprises a plurality of nodes (A . . . F) forming a network (1) and said control information (WD) indicates an address of a predetermined node.

7. The communication method according to claim 6, wherein, if nodes (A . . . F) receive said wake-up signal (WU) via said communication channel and are not addressed by said control information (WD), said nodes (A . . . F) do not listen to said communication channel and/or transmit any data via said communication channel for a predetermined period of time.

8. The communication method according to claim 7, wherein said control information (WD) indicates the duration of a subsequent data transmission and said predetermined period of time is the duration of said subsequent data transmission time indicated by said control information (WD).

9. The communication method according to claim 1, wherein said control information (WD) indicates a time point at which said source node (B) starts a data transmission and said destination node (A) receiving said control information (WD) starts the listening to a communication channel at said time point.

10. The communication method according to claim 9, wherein said control information (WD) indicates the period between the time point at which the control information is transmitted and time point at which said source node (B) starts a data transmission.

11. The communication method according to claim 10, wherein said wake-up signal (WU) comprises a repetition of said signal block (SB), wherein, for each of the successive signal blocks (SB), the period between the time point at which the control information is transmitted and time point at which said source node (B) starts a data transmission is calculated.

12. The communication method according to claim 1, wherein said control information (WD) indicates a selection of a predetermined communication channel.

13. The communication method according to claim 1, wherein said nodes (A . . . F) interchange information of listen timing (T₁, T₂) and each node accumulates said timing information (T₁, T₂), wherein said source node (B) calculates the start of said wake-up signal (WU) based on said timing information (T₁, T₂).

14. The communication method according to claim 13, wherein each node calculates clock drifts with respect to any other peer node based on said timing information (T₁, T₂), wherein said source node (B) calculates the start and/or the duration of said wake-up signal (WU) based on said drift.

15. A communication system constituted by at least two nodes (A, B), the system comprising:

means (3) for listening, on a destination node (A) side, to a communication channel periodically, wherein the listen duration is T_L and the listen periodicity is T_PL and T_L<

<

T_PL; and

means (3) for transmitting a wake-up signal (WU) from a source node (B) to said destination node (A) via said communication channel;

characterised in that

said wake-up signal (WU) comprises a preamble (WP) and a control information (WD), wherein the duration of a signal block (SB) formed by said preamble (WP) and said control information (WD) is T_SB and 2×

T_SB<

T_L; and

in said communication system the communication between nodes (A . . . F) is controlled based on said control information (WD).

16. The communication system according to claim 15, wherein said communication system is a wireless communication system.

17. The communication system according to claim 15, wherein the listen duration is T_L and the listen periodicity is T_PL and 2T_L<

<

T_PL.

18. The communication system according to claim 15, wherein said communication system comprises a plurality of nodes (A . . . F) forming a network (1) and said destination node (A) is adapted to detect whether said control information (WD) indicates that said source node (B) wants to join said network (1).

19. The communication system according to claim 15, wherein said communication system comprises a plurality of nodes (A . . . F) forming a network (1) and said destination node (A) is adapted to detect whether said control information (WD) indicates that said source node (B) is still present in said network (1).

20. The communication system according to claim 15, wherein said communication system comprises a plurality of nodes (A . . . F) forming a network (1) and said destination node (A) is adapted to detect whether said control information (WD) indicates an address of a predetermined node.

21. The communication system according to claim 20, wherein said destination node (A) is adapted to stop the listening to said communication channel and/or the transmission of any data via said communication channel for a predetermined period of time, if said destination node (A) is not addressed by said control information (WD).

22. The communication system according to claim 21, wherein said destination node (A) is adapted to detect whether said control information (WD) indicates the duration of a subsequent data transmission and said predetermined period of time is the duration of said subsequent data transmission time indicated by said control information (WD).

23. The communication system according to claim 15, wherein said destination node (A) is adapted to detect whether said control information (WD) indicates a time point at which said source node (B) starts a data transmission and to listen to a communication channel at said time point.

24. The communication system according to claim 23, wherein said control information (WD) indicates the period between the time point at which the control information is transmitted and time point at which said source node (B) starts a data transmission.

25. The communication system according to claim 24, wherein said source node (B) is adapted to generate a wake-up signal (WU) comprising a repetition of said signal block (SB), wherein said source node (B) comprises means for calculating, for each of the successive signal blocks (SB) in said wake-up signal (WU), the period between the time point at which the control information is transmitted and the time point at which said source node (B) starts a data transmission.

26. The communication system according to claim 15, wherein said destination node (A) is adapted to detect whether said control information (WD) indicates a predetermined communication channel.

27. The communication system according to claim 15, wherein said nodes (A . . . F) are adapted to interchange information of listen timing (T₁, T₂) and each node is adapted to accumulate said timing information (T₁, T₂), wherein said source node (B) is adapted to calculate the start of said wake-up signal (WU) based on said timing information (T₁, T₂).

28. The communication system according to claim 27, wherein each node is adapted to calculate clock drifts with respect to any other peer node based on said timing information (T₁, T₂), wherein said source node (B) is adapted to calculate the start and/or the duration of said wake-up signal (WU) based on said drift.

29. Apparatus for requesting services from a remote apparatus, said remote apparatus (A) listens to a communication channel periodically, wherein the listen duration is T_L and the listen periodicity is T_PL and T_L<

<

T_PL, the requesting apparatus (B) comprising;

wake-up signal (WU) generating means for generating a wake-up signal (WU);

control means (4) for controlling said wake-up signal generating means to generate said wake-up signal (WU), if a service has to be requested from said remote apparatus; and

transmitting means (3) for transmitting the wake-up signal (WU) generated by said wake-up signal (WU) generating means to said remote apparatus via said communication channel, characterised in that

said wake-up signal (WU) comprises a preamble (WP) and a control information (WD), wherein the duration of the signal block (SB) formed by said preamble (WP) and said control information (WD) is T_SB and 2×

T_B<

T_L.

30. The apparatus according to claim 29, wherein the listen duration is T_L and the listen periodicity is T_PL and 2T_L<

<

T_PL.

31. The apparatus according to claim 29, wherein said wake-up signal generating means is adapted to add a control information (WD) including a network (1) join request to said wake-up signal (WU).

32. The apparatus according to claim 29, wherein said wake-up signal generating means is adapted to add a control information (WD) including a presence notice to said wake-up signal (WU).

33. The apparatus according to claim 29, wherein said wake-up signal generating means is adapted to add a control information (WD) indicating the address of a remote apparatus from which a service has to be requested to said wake-up signal (WU).

34. The apparatus according to claim 29, wherein said wake-up signal generating means is adapted to add a control information (WD) indicating the duration of a subsequent data transmission to said wake-up signal (WU).

35. The apparatus according to claim 29, wherein said wake-up signal (WU) generating means is adapted to add a control information (WD) indicating a time point at which the transmitting means (3) starts a data transmission to said wake-up signal (WU).

36. The apparatus according to claim 35, wherein said control information (WD) indicates the period between the time point at which the control information is transmitted and time point at which said the transmitting means (3) starts a data transmission.

37. The apparatus according to claim 36, wherein said wake-up signal (WU) generating means is adapted to generate a wake-up signal (WU) comprising a repetition of said signal block (SB), wherein said wake-up signal (WU) generating means comprises means for calculating, for each of the successive signal blocks (SB) in said wake-up signal (WU), the period between the time point at which the control information is transmitted by said transmitting means (3) and the time point at which said transmitting means (3) starts a data transmission.

38. The apparatus according to claim 29, wherein said wake-up signal generating means is adapted to add a control information (WD) indicating a predetermined communication channel to said wake-up signal (WU).

39. The apparatus according to claim 29, further comprising means for receiving information of listen timing (T₁, T₂) from a remote apparatus, wherein said control means (4) is adapted to calculate the start of said wake-up signal (WU) based on said timing information (T₁, T₂).

40. The apparatus according to claim 39, wherein said control means (4) is adapted to calculate clock drifts with respect to said remote apparatus based on said timing information (T₁, T₂) and, wherein said control means (4) is adapted to calculate the start and/or the duration of said wake-up signal (WU) based on said drift.

41. Apparatus for providing services requested from a remote apparatus, the apparatus comprising:

receiving means (3) for receiving a wake-up signal (WU) send from said remote apparatus via a communication channel;

control means (4) for controlling said receiving means (3) to listen to said communication channel periodically, wherein the listen duration is T_L and the listen periodicity is T_PL and T_L<

<

T_PL, and for providing a service, if said wake-up signal (WU) is received by said receiving means (3),

characterised in that

said wake-up signal (WU) comprises a preamble (WP) and a control information (WD), wherein the duration of the signal block (SB) formed by said preamble (WP) and said control information (WD) is T_SB and 2×

T_SB<

T_L;

a separating means separates said control information (WD) from said wake-up signal (WU); and

said control means (4) controls said receiving means (3) based on said control data separated by said separating means.

42. The apparatus according to claim 41, wherein the listen duration is T_L and the listen periodicity is T_PL and 2T_L<

<

T_PL.

43. The apparatus according to claim 41, wherein said control means (4) is adapted to detect whether said control information (WD) includes a network (1) join request.

44. The apparatus according to claim 41, wherein said control means (4) is adapted to detect whether said control information (WD) includes a presence notice.

45. The apparatus according to claim 41, wherein said control means (4) is adapted to detect whether said control information (WD) includes an apparatus address.

46. The apparatus according to claim 45, wherein said control means (4) is adapted to control said receiving means (3) to stop the listening to said communication channel and/or the transmission of any data via said communication channel for a predetermined period of time, if said service providing apparatus is not addressed by said control information (WD).

47. The apparatus according to claim 46, wherein said control means (4) is adapted to detect whether said control information (WD) indicates the duration of a subsequent data transmission of said remote apparatus and wherein, said predetermined period of time is the duration of said subsequent data transmission time indicated by said control information (WD).

48. The apparatus according to claim 41, wherein said control means (4) is adapted to detect whether said control information (WD) indicates a time point at which said remote apparatus starts a data transmission and to control said receiving means (3) to listen to a communication channel at said time point.

49. The apparatus according to claim 48, wherein said control information (WD) indicates the period between the time point at which the control information is transmitted and time point at which said the transmitting means (3) starts a data transmission.

50. The apparatus according to claim 41, wherein said control means (4) is adapted to detect whether said control information (WD) indicates a selection of a predetermined communication channel.

51. The apparatus according to claim 41, wherein said control means (4) is adapted to detect information of listen timing (T₁, T₂) of a remote apparatus received by said receiving means (3), wherein said control means (4) is adapted to calculate the start of a wake-up signal (WU) based on said timing information (T₁, T₂).

52. The apparatus according to claim 51, wherein said control means (4) is adapted to calculate clock drifts with respect to said remote apparatus based on said timing information (T₁, T₂) and, wherein said control means (4) is adapted to calculate the start and/or the duration of a wake-up signal (WU) based on said drift.