System and method for synchronizing TDMA mesh networks

• US 8,059,578 B2
• Filed: 07/24/2006
• Issued: 11/15/2011
• Est. Priority Date: 07/24/2006
• Status: Active Grant

• Current Assignee: Stingray IP Solutions LLC (Acacia Research Corporation)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Rudnick, William M.
• Primary Examiner(s): Afshar; Kamran
• Assistant Examiner(s): MATHARU, MANPREET S
• Application Number:
  US11/459,389
• Publication Number:
  US 20080019328A1
• Time in Patent Office: 1,940 Days
• Field of Search: 455/448, 455/451, 455/452, 455/452.2, 455/453, 370/330, 370/337, 370/338, 370/510, 370/512, 370/328, 370/321, 370/458, 370/350, 370/324
• US Class Current: 370/321
• CPC Class Codes: H04J 4/00 Combined time-division and frequency-division multiplex systems H04J13/00 takes precedence ; data transmission H04L5/26; telemetry G08C15/00
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 56/002 Mutual synchronization

Abstract

A communications system includes a plurality of Time Division Multiple Access (TDMA) mesh networks formed by a plurality of wireless nodes. Each plurality of wireless nodes within a respective TDMA mesh network comprises a transmitter and receiver that communicate on a primary and optionally at least one secondary frequency and use a TDMA epoch that is divided into at least a beacon interval using the primary frequency and a digital data interval using the primary and secondary frequencies. The wireless nodes are synchronized to each other such that the start of TDMA epochs for each TDMA mesh network overlap and have the same TDMA epoch duration or an integer multiple thereof.

Claims

1. A communications system, comprising:

first and second Time Division Multiple Access (TDMA) mesh networks, each comprising a plurality of wireless nodes;

each node of the plurality of wireless nodes within respective first and second TDMA mesh networks comprising a transmitter and receiver that communicate on a primary and at least one secondary frequency and use a TDMA epoch that is divided into at least a beacon interval using the primary frequency and a digital data interval using both the primary and secondary frequencies, wherein the wireless nodes in first and second TDMA mesh networks are synchronized to each other such that a start of TDMA epoch in the first TDMA mesh network overlaps with the start of a TDMA epoch in the second TDMA network and each have the same TDMA epoch duration or an integer multiple thereof and an unused digital data secondary frequency TDMA usage for the second TDMA mesh network falls into an unused portion of the secondary frequency usage map of the first TDMA mesh network.

2. The communications system according to claim 1, and further comprising a gateway wireless node that is common to said first and second TDMA mesh networks and operative for transmitting beacons for each of said first and second TDMA mesh networks that do not conflict with each other.

3. The communications system according to claim 2, wherein said gateway wireless node further comprises a transmitter that transmits a separate beacon for each of the first and second TDMA mesh networks.

4. The communications system according to claim 1, and further comprising a phantom node that is common for each of said first and second TDMA mesh networks and whose start of a TDMA epoch in said first TDMA mesh network is at a desired offset based upon an inferred start of a TDMA epoch of said second TDMA mesh network.

5. A communications system, comprising:

first and second Time Division Multiple Access (TDMA) mesh networks, each comprising a plurality of wireless nodes;

each plurality of wireless nodes within respective first and second TDMA mesh networks comprising a transmitter and receiver that communicate on a primary and at least one secondary frequency and use a TDMA epoch that is divided into at least a beacon interval using the primary frequency and a digital data interval using both the primary and secondary frequencies, wherein the wireless nodes in first and second TDMA mesh networks are synchronized to each other and the beacon interval within the first TDMA mesh network falls within the digital data interval of the second TDMA mesh network and an unused digital data secondary frequency TDMA usage for the second TDMA mesh network falls into an unused portion of the secondary frequency usage map of the first TDMA mesh network such that the beacon transmissions of the first TDMA mesh network do not collide with the beacon transmissions of the second TDMA network and each TDMA epoch for first and second TDMA mesh networks have the same TDMA epoch duration on an integer multiple thereof.

6. The communications system according to claim 5, and further comprising a channel reservation for a beacon interval during a digital data interval corresponding to the first TDMA mesh network'"'"'s beacon interval to prevent any wireless nodes from making digital data transmissions or beacon transmissions that collide with the beacon transmissions from the first TDMA mesh network.

7. The communications system according to claim 5, and further comprising a gateway wireless node that is common to said first and second TDMA mesh networks and operative for transmitting beacons for each TDMA mesh network that do not conflict with each other.

8. The communications system according to claim 5, wherein said gateway wireless node further comprises a transmitter that transmits a separate beacon for each of the first and second TDMA mesh networks.

9. The communications system according to claim 5, and further comprising a phantom node that is common for each of said first and second TDMA mesh networks and whose start of the first TDMA epoch in a TDMA mesh network is at a desired offset based upon an inferred start of a TDMA epoch in the second TDMA mesh network.

10. The communications system according to claim 5, wherein said first and second TDMA mesh networks are synchronized to each other such that the start of TDMA epochs for first and second TDMA mesh networks overlap and have the same TDMA epoch duration or an integer multiple thereof.

11. A method for synchronizing Time Division Multiple Access (TDMA) mesh networks, which comprises:

allocating a primary frequency and at least one secondary frequency within first and second TDMA mesh networks, each having a plurality of wireless nodes and communicating with each other using a TDMA epoch that is divided into at least a beacon interval using the primary frequency and a digital data interval using both the primary and secondary frequencies; and

synchronizing the first and second TDMA mesh networks with each other by overlapping the start of a TDMA epoch in the first TDMA mesh network with the start of a TDMA epoch in the second TDMA network, wherein each TDMA mesh network has the same TDMA epoch duration or an integer multiple thereof and an unused digital data secondary frequency TDMA usage for the second TDMA mesh network falls into an unused portion of the secondary frequency usage map of the first TDMA mesh network.

12. The method according to claim 11, which further comprises establishing a gateway wireless node that is common to the first and second TDMA mesh networks and operative for transmitting beacons for each of said first and second TDMA mesh networks that do not conflict with each other.

13. The method according to claim 12, which further comprises forming the gateway wireless node between said first and second TDMA mesh networks.

14. The method according to claim 12, which further comprises forming the gateway wireless node as a radio comprising a transmitter that transmits a separate beacon for each of the first and second TDMA mesh networks.

15. The method according to claim 11, which further comprises forming a phantom node that is common for each of the first and second TDMA mesh networks and whose start of a TDMA epoch is at a desired offset based upon an inferred start of the first TDMA epoch.

16. A method according to claim 11, which further comprises forming the beacon interval within the first mesh network to fall within the digital data interval of the second TDMA mesh network such that the beacon transmissions of the first TDMA mesh network does not collide with those beacon transmissions of the second TDMA mesh network.

17. A method according to claim 16, which further comprises establishing within first and second TDMA mesh networks a channel reservation during a digital data interval corresponding to another TDMA mesh network'"'"'s beacon interval to prevent any wireless nodes from making digital data transmissions or beacon transmissions that would collide with the beacon transmissions from the second TDMA mesh network.

18. A method according to claim 16, which further comprises forming the beacon interval of the first TDMA mesh network to fall within the digital data interval and a digital voice interval of the second TDMA mesh network.

19. A method for synchronizing Time Division Multiple Access (TDMA) mesh networks, which comprises:

allocating a primary frequency and at least one secondary frequency within first and second TDMA mesh networks, each having a plurality of wireless nodes and communicating with each other using a TDMA epoch that is divided into at least a beacon interval using the primary frequency and a digital data interval using both the primary and secondary frequencies; and

synchronizing the beacon interval within the first TDMA mesh network to fall within the unused portion of the digital data interval of the second TDMA mesh network such that the beacon transmissions of the first TDMA mesh network does not collide with those beacon transmissions of the second TDMA mesh network and a TDMA epoch for first and second TDMA mesh networks have the same TDMA epoch duration or an integer multiple thereof.

20. A method according to claim 19, which further comprises establishing within first and second TDMA mesh networks a channel reservation during a digital data interval corresponding to the first TDMA mesh network'"'"'s beacon interval to prevent any wireless nodes from making digital data transmissions or beacon transmissions that would collide with the beacon transmissions from the second TDMA mesh network.

21. A method according to claim 20, which further comprises forming the beacon interval of the first TDMA mesh network to fall within the digital data interval and a digital voice interval of the second TDMA mesh network.

22. A method according to claim 19, which further comprises establishing a gateway wireless node that is common to the first and second TDMA mesh networks and operative for transmitting beacons for the first and second TDMA mesh networks that do not conflict.

23. A method according to claim 19, which further comprises forming the gateway wireless node as a radio comprising a transmitter that transmits separate beacons for each of the first and second TDMA mesh networks.

24. A method according to claim 19, which further comprises forming a phantom node that is common for the first TDMA mesh networks whose start of a TDMA epoch is at a desired offset based upon an inferred start of the TDMA epoch of the second TDMA mesh network.

25. The method according to claim 19, which further comprises synchronizing the first and second TDMA mesh networks with each other by overlapping the start of a TDMA epoch for the first TDMA mesh network with the second TDMA mesh network, wherein first and second TDMA mesh networks have the same TDMA epoch duration or an integer multiple thereof.