METHOD TO BOOTSTRAP INTO A FREQUENCY AGILE AD HOC NETWORK OF RADIOS THAT USE A NON-DETERMINISTIC FREQUENCY PATTERN

• US 20130202013A1
• Filed: 02/07/2012
• Published: 08/08/2013
• Est. Priority Date: 02/07/2012
• Status: Active Grant

• Current Assignee: Stingray IP Solutions LLC (Acacia Research Corporation)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Van Stralen, Nick A., Hessel, Clifford
• Granted Patent: US 9,066,320 B2
• Time in Patent Office: Days
• US Class Current: 375/133
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A method to facilitate late entry of a late entrant node into an ad-hoc radio network involves accessing from a memory at the late entrant node an initial frequency hopping sequence for the ad-hoc radio network. The late entrant node uses at least the initial frequency hopping sequence to determine a first frequency to monitor during a communication epoch corresponding to one of the frequency hops. The late entrant node thereafter monitors the first frequency to detect the presence of a beacon signal transmitted by a participating node of the network. Subsequently, the late entrant node determines a second frequency included in the current hopping sequence of the network based on information contained in the beacon signal.

Claims

1. A method for facilitating late entry of a late entrant node into an ad-hoc radio network, comprising:

accessing from a memory at the late entrant node an initial frequency hopping sequence for said ad-hoc radio network, said initial frequency hopping sequence specifying a plurality of frequencies, each respectively assigned to one of a plurality of defined frequency hops of said frequency hopping sequence;

using at least said initial frequency hopping sequence at said late entrant node to determine at least a first frequency to monitor during a communication epoch corresponding to one of said frequency hops, said first frequency included in a current hopping sequence of said ad-hoc network;

detecting the presence of a signal transmitted by a participating node of said network during said communication epoch by monitoring at least said first frequency; and

determining a second frequency included in said current hopping sequence of said network based on information contained in said signal.

2. The method according to claim 1, further comprising determining said first frequency by accessing an ordered list which specifies a plurality of alternate frequencies for each of said defined frequency hops.

3. The method according to claim 2, further comprising specifying with said ordered list an order in which said alternate frequencies are to be monitored by said late entrant node.

4. The method according to claim 2, further comprising monitoring at least one of said plurality of frequencies specified in said initial hopping sequence for a defined frequency hop and, if said signal is not detected, then monitoring at least one said alternate frequency for said defined frequency hop.

5. The method according to claim 4, further comprising monitoring in a sequential order each of said alternate frequencies for said defined frequency hop until said signal is detected.

6. The method according to claim 5, further comprising specifying said sequential order with said ordered list.

7. The method according to claim 1, further comprising continuing to monitor said first frequency during at least a second communication epoch, and determining a third frequency included in said current hopping sequence of said network based on information contained in said signal.

8. The method according to claim 7, wherein said third frequency specified in said signal is chosen for inclusion in said signal in accordance with a pseudorandom selection scheme.

9. The method according to claim 7, wherein said third frequency is selected from the group consisting of a next frequency and a next+1 frequency in said current hopping sequence.

10. The method according to claim 1, further comprising:

detecting the presence of a second signal by monitoring said second frequency; and

determining a third frequency included in said current hopping sequence of said network based on information contained in said second signal.

11. The method according to claim 1, further comprising monitoring during each of said defined frequency hops a corresponding one of said plurality of frequencies included in said initial frequency hopping sequence.

12. The method according to claim 11, further comprising determining said first frequency for a plurality of said defined frequency hops by accessing an ordered list which specifies a plurality of alternate frequencies for each of said defined frequency hops.

13. The method according to claim 1, further comprising monitoring at least one frequency included in said initial frequency hopping sequence for at least N+1 hops where N is the total number of hops in said initial frequency hopping sequence.

14. The method according to claim 13, further comprising iteratively monitoring each frequency included in said initial frequency hopping sequence for at least N+1 hops until said signal is detected.

15. The method according to claim 1, wherein a timing of said communication epoch is determined in accordance with a stable source of timing information, and said late entrant node accesses said stable source of timing information to determine a timing of said epoch.

16. The method according to claim 15, wherein said stable source of timing information is a GPS signal.

31. The communication transceiver according to claim 13, wherein said computer processing device is further configured to cause said communication transceiver to iteratively monitor each frequency included in said initial frequency hopping sequence for at least N+1 hops until said signal is detected.

32. The communication transceiver according to claim 1, wherein said computer processing device is further configured to determine a timing of said communication epoch in accordance with a stable source of timing information.

33. The communication transceiver according to claim 15, wherein said stable source of timing information is a GPS signal.

17. A method for facilitating late entry of a late entrant node into an ad-hoc radio network, comprising:

accessing from a memory at the late entrant node an initial frequency hopping sequence for said ad-hoc radio network, said initial frequency hopping sequence specifying a plurality of frequencies, each respectively assigned to one of a plurality of defined frequency hops of said frequency hopping sequence;

detecting the presence of a signal transmitted by a participating node of said network during said communication epoch by monitoring at least a first frequency; and

determining a second frequency included in said current hopping sequence of said network based on information contained in said signal.

18. A communication transceiver for an ad-hoc radio network, comprising:

a computer processing device configured to

access from a memory at the communication transceiver an initial frequency hopping sequence for said ad-hoc radio network, said initial frequency hopping sequence specifying a plurality of frequencies, each respectively assigned to one of a plurality of defined frequency hops of said frequency hopping sequence;

use at least said initial frequency hopping sequence at said communication transceiver to determine at least a first frequency to monitor during a communication epoch corresponding to one of said frequency hops, said first frequency included in a current hopping sequence of said ad-hoc network;

detect the presence of a signal transmitted by a participating node of said network during said communication epoch by monitoring at least said first frequency; and

determine a second frequency included in said current hopping sequence of said network based on information contained in said signal.

19. The communication transceiver according to claim 18, wherein said computer processing device is further configured to determine said first frequency by accessing an ordered list which specifies a plurality of alternate frequencies for each of said defined frequency hops.

20. The communication transceiver according to claim 19, wherein said ordered list specifies an order in which said alternate frequencies are to be monitored by said communication transceiver.

21. The communication transceiver according to claim 19, wherein said computer processing device is further configured to cause said communication transceiver to monitor at least one of said plurality of frequencies specified in said initial hopping sequence for a defined frequency hop and, if said signal is not detected, then monitor at least one said alternate frequency for said defined frequency hop.

22. The communication transceiver according to claim 21, wherein said computer processing device is further configured to cause said communication transceiver to monitor in a sequential order each of said alternate frequencies for said defined frequency hop until said signal is detected.

23. The communication transceiver according to claim 22, wherein said sequential order is specified with said ordered list.

24. The communication transceiver according to claim 18, wherein said computer processing device is further configured to cause said communication transceiver to continue to monitor said first frequency during at least a second communication epoch, and determines a third frequency included in said current hopping sequence of said network based on information contained in said signal.

25. The communication transceiver according to claim 24, wherein said third frequency specified in said signal is determined for inclusion in said signal in accordance with a pseudorandom selection scheme.

26. The communication transceiver according to claim 24, wherein said third frequency is selected from the group consisting of a next frequency and a next+1 frequency in said current hopping sequence.

27. The communication transceiver according to claim 18, wherein said computer processing device is further configured to:

detect the presence of a second signal by monitoring said second frequency; and

determine a third frequency included in said current hopping sequence of said network based on information contained in said second signal.

28. The communication transceiver according to claim 18, wherein said computer processing device is further configured to cause said communication transceiver to monitor during each of said defined frequency hops a corresponding one of said plurality of frequencies included in said initial frequency hopping sequence.

29. The communication transceiver according to claim 28, wherein said computer processing device is further configured to determine said first frequency for a plurality of said defined frequency hops by accessing an ordered list which specifies a plurality of alternate frequencies for each of said defined frequency hops.

30. The communication transceiver according to claim 18, wherein said computer processing device is further configured to cause said communication transceiver to monitor at least one frequency included in said initial frequency hopping sequence for at least N+1 hops where N is the total number of hops in said initial frequency hopping sequence.