MANAGING COEXISTENCE AMONG SIGNALING PROTOCOLS ON A SHARED MEDIUM

• US 20100074243A1
• Filed: 06/16/2009
• Published: 03/25/2010
• Est. Priority Date: 06/16/2008
• Status: Active Grant

• Current Assignee: Gigle Networks Iberia, S.L. (Broadcom, Inc.), HiSilicon Technologies Ltd (Huawei Investment & Holding Co., Ltd.), MediaTek, Inc., Panasonic Corporation (Panasonic Holdings Corporation), STMicroelectronics Incorporated (STMicroelectronics NV)
• Original Assignee: Gigle Semiconductor, Inc. (Broadcom, Inc.), HiSilicon Technologies Ltd (Huawei Investment & Holding Co., Ltd.), Spidcom Technologies SA (MediaTek, Inc.), Panasonic Communications Company Limited (Panasonic Holdings Corporation), Intellon Corporation (Qualcomm, Inc.)
• Inventors: Dixon, Paul, Isson, Olivier, Yonge, Lawrence W. III, Kurobe, Akio, Earnshaw, William E., Koga, Hisao, Kodama, Nobutaka, Katar, Srinivas, Molina, Jose Abad, Galli, Stefano, Logvinov, Oleg
• Granted Patent: US 8,295,301 B2
• Time in Patent Office: Days
• US Class Current: 370/343
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04B 7/2656 for structure of frame, burst

Abstract

A method is described for communicating among multiple devices over a shared communication medium. The method includes, in a schedule among multiple subsets of the devices that includes at least one respective time slot for each subset, transmitting from at least one of the devices in a given subset a presence signal associated with the given subset within a time slot for the given subset. A presence signal associated with a given subset is configured to indicate the presence of at least one device in the given subset. The method also includes communicating among devices in a given subset based on presence signals detected from one or more devices in at least one different subset.

Claims

1. A method for communicating among multiple devices over a shared communication medium, the method comprising:

in a schedule among multiple subsets of the devices that includes at least one respective time slot for each subset, transmitting from at least one of the devices in a given subset a presence signal associated with the given subset within a time slot for the given subset, where a presence signal associated with a given subset is configured to indicate the presence of at least one device in the given subset; and

communicating among devices in a given subset based on presence signals detected from one or more devices in at least one different subset.

2. The method of claim 1, wherein respective presence signals associated with different subsets are unique.

3. The method of claim 2, wherein respective presence signals associated with different subsets include multiple carrier frequencies modulated using a unique sequence of phases.

4. The method of claim 3, wherein the sequence of phases comprises a sequence of two phase values that differ by 180 degrees.

5. The method of claim 3, wherein the sequence of phases is determined from a stored list of phases starting at a given offset, where each unique sequence of phases starts at a different offset.

6. The method of claim 2, wherein the schedule is a recurring schedule in which the time slots are synchronized to an alternating current line cycle on the shared communication medium.

7. The method of claim 6, wherein the time slots are at different predetermined offsets from a zero crossing of the alternating current line cycle.

8. The method of claim 7, wherein the predetermined offsets are in proximity to the zero crossing of the alternating current line cycle.

9. The method of claim 7, wherein the time slots each include time reserved for one of the presence signals and time margins on either side that enable one of the presence signals to be identifiable when the zero crossing is not accurately detected.

10. The method of claim 2, wherein, during the time slots, devices that are not transmitting presence signals scan for presence signals.

11. The method of claim 10, further comprising synchronizing to a detected zero crossing at a device in a first subset in response to receipt of a resynchronization signal from a device in a second subset different from the first subset.

12. The method of claim 11, wherein the resynchronization signal is transmitted from the device in the second subset in a time slot following a time slot in which a presence signal is transmitted from the device in the first subset.

13. The method of claim 11, wherein the device in the second subset transmits the resynchronization signal in response to an indication from at least one device that one or more presence signals are out of synchronization.

14. The method of claim 13, wherein a presence signal is out of synchronization if it is detected outside of a time slot for a subset with which the presence signal is associated.

15. The method of claim 2, wherein the schedule includes at least one presence signal time slot for each subset and time intervals including communication time slots allocated for communicating among devices in a given subset.

16. The method of claim 15, further comprising requesting to share the time intervals among devices of different subsets using either time division multiplexing or frequency division multiplexing based on signals sent during the time slots.

17. The method of claim 16, wherein a device rejects a request to use frequency division multiplexing to select use of time division multiplexing to share the time intervals among devices of different subsets.

18. The method of claim 15, wherein presence signals sent by devices of at least one subset are coordinated by a master device for that subset.

19. The method of claim 18, further comprising devices in a subset communicating detected presence signal information to the master for that subset.

20. The method of claim 2, wherein at least one device in a subset transmits presence signals for that subset.

21. The method of claim 20, wherein multiple devices in a subset transmit presence signals for that subset.

22. The method of claim 21, wherein all devices in a subset transmit presence signals for that subset.

23. The method of claim 21, wherein multiple devices in a subset that transmit presence signals for that subset transmit identical presence signals.

24. The method of claim 23, wherein the identical presence signals add constructively so that the identical presence signals are distinguishable from presence signals transmitted by devices in other subsets.

25. The method of claim 2, wherein detected presence signals below a threshold are ignored.

26. The method of claim 1, wherein the presence signal time slots for transmitting presence signals are separated by time intervals including communication time slots allocated for communicating among devices in a given subset.

27. The method of claim 26, wherein time slots are assigned to a given subset based on subsets identified by the presence signals.

28. The method of claim 26, wherein a first time slot assigned to a first subset and a second time slot assigned to a second subset are separated by a silence margin.

29. The method of claim 26, further comprising assigning time slots to subsets based on at least one of latency and throughput.

30. The method of claim 29, wherein time slots are assigned for a given subset spread over most of the time interval to provide low latency.

31. The method of claim 29, wherein time slots are assigned for a given subset contiguously within the time interval to provide high throughput.

32. The method of claim 26, further comprising a device in a first subset using a time slot assigned to a second subset when no device in the second subset communicates during one or more slots previously assigned to the second subset.

33. The method of claim 32, wherein a device in the first subset requests permission from a master device before using the time slot assigned to the second subset.

34. The method of claim 32, wherein a device in the first subset uses the time slot assigned to the second subset after determining that a signal to noise ratio suggests interference with a device in the second subset is improbable.

35. The method of claim 26, a device in a first subset requests use of all of the time slots in a given interval for use by one or more devices in the first subset.

36. The method of claim 1, wherein devices in different subsets use different physical layer protocols.

37. The method of claim 36, wherein devices in different subsets use signals that overlap in their spectra.

38. The method of claim 36, wherein at least one of the subsets utilizes orthogonal frequency-division multiplexing.

39. A system, comprising:

a communication medium;

a first subset of devices coupled to the communication medium; and

a second subset of devices coupled to the communication medium;

wherein at least one of the devices in a given subset of multiple subsets of devices, including at least the first and second subsets of devices, is configured to

transmit a presence signal associated with the given subset within a time slot for the given subset according to a schedule that includes at least one respective time slot for each subset, where a presence signal associated with a given subset is configured to indicate the presence of at least one device in the given subset, and

communicate among other devices in the given subset based on presence signals detected from one or more devices in at least one different subset.