CONTENTION SLOTS IN A SHARED ROBUST SCHEME

• US 20090109992A1
• Filed: 10/30/2008
• Published: 04/30/2009
• Est. Priority Date: 10/30/2007
• Status: Active Grant

• Current Assignee: Sigma Designs Israel S.D.I Ltd. (Uphill Investment Co.)
• Original Assignee: Sigma Designs Israel S.D.I Ltd. (Uphill Investment Co.)
• Inventors: Sterenson, Ronald Bruce, LURIE, AHARONA
• Granted Patent: US 8,018,965 B2
• Time in Patent Office: Days
• US Class Current: 370/445
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 12/40 Bus networks
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 47/10 Flow control; Congestion control

Abstract

A method includes receiving a schedule of transmission start slots on a network node, the slots representing reserved and/or nonreserved opportunities for initiating data transmission by at least one network device in a network, the reserved opportunities associated with specific network devices, and the non-reserved opportunities available for non-reserved use by any network device on the network, and adjusting the schedule in accordance with successful transmissions by other network nodes. Another method includes generating a schedule of transmission start slots on a master node, where the slots represent reserved and/or nonreserved transmission initiation opportunities for the initiation of data transmission by at least one of a plurality of network devices in a network, the reserved opportunities being associated with specific network nodes, and the nonreserved opportunities being available for nonreserved use by any the network devices on the network, and distributing the schedule to the network devices.

Claims

1. A method comprising:

receiving a schedule of transmission start slots on a network node, wherein said transmission start slots represent at least one of reserved and non reserved transmission initiation opportunities for the initiation of data transmission by at least one of a plurality of network devices in a network, said reserved opportunities being associated with specific said network devices, and said non reserved opportunities being available for non reserved use by any said network devices on said network; and

adjusting said schedule in accordance with successful transmissions by other network nodes.

2. The method according to claim 1 and also comprising:

attempting to transmit in accordance with a said transmission start slot representing a said non reserved transmission opportunity.

3. The method according to claim 2 and also comprising:

detecting at least an unsuccessful attempt to transmit;

backing off in accordance with a random number of said non scheduled transmission initiation opportunities as per said schedule;

reattempting to transmit in accordance with a said transmission start slot representing a subsequent said non scheduled transmission opportunity as per said schedule.

4. The method according to claim 3 and wherein said detecting comprises:

transmitting a request to transmit (RTS); and

waiting a predefined period of time to receive a “

clear to send”

(CTS) in reply to said RTS.

5. The method according to claim 3 and wherein said detecting comprises:

using physical collision detection based on echo cancellation.

6. The method according to claim 1 and wherein said adjusting comprises:

detecting transmissions by other said network nodes in accordance with said schedule; and

delaying said transmission start slots in accordance with a transmission length of said detected transmissions.

7. The method according to claim 1 and wherein said network uses a powerline medium.

8. The method according to claim 2 and also comprising:

transmitting an in use signal;

expanding said transmission start slot to a standard sized backoff window;

backing off within said backoff window in accordance with a random duration;

transmitting data; and

resolving any ensuing detected collisions within said backoff window as necessary.

9. A method comprising:

generating a schedule of transmission start slots on a master node, wherein said transmission start slots represent at least one of reserved and non reserved transmission initiation opportunities for the initiation of data transmission by at least one of a plurality of network devices in a network, said reserved opportunities being associated with specific network nodes, and said non reserved opportunities being available for non reserved use by any said network devices on said network; and

distributing said schedule to said network devices.

10. The method according to claim 9 and also comprising:

tracking transmissions by said network devices in accordance with said schedule; and

adjusting said schedule by rescheduling said transmission start slots in accordance with at least a length of said tracked transmissions.

11. The method according to claim 10 and wherein said tracking also comprises:

detecting non reserved transmissions from among said tracked transmissions; and

adding scheduled transmission start opportunities for said network devices associated with said detected non reserved transmissions to a new said schedule to be distributed to said network devices.

12. The method according to claim 10 and wherein said tracking also comprises:

detecting a lack of reserved transmissions from among said tracked transmissions; and

removing scheduled transmission start opportunities for said network nodes associated with said lack of scheduled transmissions from a new said schedule to be distributed to said network devices.

13. The method according to claim 9 and wherein said network uses a powerline medium.

14. A master node comprising:

a scheduler to generate a schedule of transmission start slots, wherein said transmission start slots represent at least one of reserved and non reserved transmission initiation opportunities for the initiation of data transmission by at least one of a plurality of network devices in a network, said reserved opportunities being associated with specific said network devices, and said non reserved opportunities being available for non reserved use by any said network devices on said network; and

means to distribute said schedule to said network devices.

15. The master node according to claim 14 and also comprising:

means to track transmissions by said network devices in accordance with said schedule; and

a schedule adjuster to adjust said schedule by rescheduling said transmission start slots in accordance with at least a length of said tracked transmissions.

16. The master node according to claim 15 and wherein said schedule adjuster also comprises means to add said scheduled transmission start opportunities for said network nodes associated with non scheduled transmissions to a new said schedule to be distributed to said network devices.

17. The master node according to claim 15 and wherein said tracking also comprises and wherein said schedule adjuster also comprises means to remove said scheduled transmission start opportunities from a new said schedule to be distributed to said network nodes, wherein said transmission start opportunities are associated with said network nodes for which there are no associated said scheduled transmissions detected.

18. The master node according to claim 14 and wherein said network uses a powerline medium.

19. A network node comprising:

means to receive a schedule of transmission start slots on a network node, wherein said transmission start slots represent at least one of reserved and non reserved transmission initiation opportunities for the initiation of data transmission by at least one of a plurality of network devices in a network, said scheduled opportunities being associated with specific said network nodes, and said non scheduled opportunities being available for non reserved use by any said network devices on said network; and

a schedule adjuster to adjust said schedule in accordance with successful transmissions by other network nodes.

20. The node according to claim 19 and also comprising:

means to transmit in accordance with a said transmission start slot representing a said non reserved transmission opportunity.

21. The node according to claim 20 and also comprising:

means to detect at least an unsuccessful attempt to transmit; and

a back off mechanism to reattempt to transmit in accordance with a random “

backing off”

in accordance with said non reserved transmission initiation opportunities as per said schedule.

22. The node according to claim 21 and wherein said means to detect comprises:

means to transmit a RTS; and

means to process an expected CTS to be received in reply to said RTS.

23. The node according to claim 21 and wherein said means to detect comprises:

a physical collision detector to use echo cancellation to detect collisions.

24. The node according to claim 19 and wherein said adjustor comprises:

means to detecting transmissions by other said network nodes in accordance with said schedule; and

a rescheduler to delay said transmission start slots in accordance with a transmission length of said detected transmissions.

25. The node according to claim 19 and wherein said network uses a powerline medium.