EFFICIENT NETWORK DISCOVERY IN FREQUENCY HOPPING NETWORKS

• US 20130094536A1
• Filed: 10/13/2011
• Published: 04/18/2013
• Est. Priority Date: 10/13/2011
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Hui, Jonathan W., Woo, Lik Chuen Alec, Hong, Wei
• Granted Patent: US 9,281,865 B2
• Time in Patent Office: Days
• US Class Current: 375/133
• CPC Class Codes: H04B 1/713 using frequency hopping

Abstract

In one embodiment, a device in a frequency hopping communication network transmits responsive beacon messages based on adaptive types of responsive beacon message transmission based on a number of received beacon requests within a given time period: the number below a threshold results in synchronized unicast messages; the number above the threshold results in unsynchronized broadcast messages. In another embodiment, the device suppresses unsolicited beacon message transmission based on a density-aware redundancy count of other unsolicited beacon message transmissions from neighboring devices. In another embodiment, the device may transmit unsolicited beacon messages according to an adaptive interval based on stability of the network. In another embodiment, the device may suppress transmission of a beacon request to join the communication network based on a density-aware redundancy count of other beacon requests from neighboring devices, and transmits beacon requests at an adaptive interval that increases in response to each unanswered beacon request.

Claims

1. A method, comprising:

receiving one or more beacon requests at a device in a frequency hopping communication network;

determining a number of received beacon requests within a given time period;

adapting a type of responsive beacon message transmission based on the number of received beacon requests within the given time period, wherein the number being below a threshold results in synchronized unicast responsive beacon message transmission type, and wherein the number being above the threshold results in unsynchronized broadcast responsive beacon message transmission type; and

transmitting one or more responsive beacon messages from the device based on the type of responsive beacon message transmission.

2. The method as in claim 1, further comprising:

transmitting one or more unsolicited beacon messages from the device; and

suppressing unsolicited beacon message transmission based on a density-aware redundancy count of other unsolicited beacon message transmissions from neighboring devices in the communication network.

3. The method as in claim 2, further comprising:

determining a stability of the communication network; and

adapting an interval of unsolicited beacon message transmission from the device based on stability of the network.

4. The method as in claim 1, further comprising:

transmitting one or more unsolicited beacon messages from the device;

determining a stability of the communication network; and

adapting an interval of unsolicited beacon message transmission from the device based on stability of the network.

5. The method as in claim 1, further comprising, in response to receiving a beacon request when a length of the given time period is not currently set to the minimum length:

setting the length of the given time period to the minimum length; and

starting a new time period as the given time period during which the number of received beacon requests is determined, wherein transmitting the one or more responsive beacon messages is at a particular chosen time prior to expiration of the new time period.

6. The method as in claim 1, wherein transmitting comprises:

transmitting one or more unsynchronized broadcast responsive beacon messages from the device; and

suppressing the transmitting one or more unsynchronized broadcast responsive beacon messages from the device based on a density-aware redundancy count of other unsynchronized broadcast responsive beacon messages from neighboring devices in the communication network.

7. A method, comprising:

transmitting one or more unsolicited beacon messages from a device in a frequency hopping communication network;

determining a density-aware redundancy count of other unsolicited beacon message transmissions from neighboring devices in the communication network during a given time period; and

suppressing unsolicited beacon message transmission during the given time period based on the density-aware redundancy count of other unsolicited beacon message transmissions from neighboring devices in the communication network during the given time period.

8. The method as in claim 7, further comprising:

determining a stability of the communication network; and

adapting an interval of unsolicited beacon message transmission from the device based on stability of the network.

9. The method as in claim 7, further comprising:

resetting, at a start of the given time period, the redundancy count to 0;

receiving one or more unsolicited beacon message transmissions from the neighboring devices;

incrementing the redundancy count in response to each received unsolicited beacon message containing a same network information version as a pending unsolicited beacon message to be transmitted; and

suppressing unsolicited beacon message transmission by transmitting the pending unsolicited beacon message for the given time period if and only if the redundancy count is less than a given threshold value.

10. The method as in claim 7, further comprising:

utilizing a single beacon message to provide network-wide parameters to joining devices and neighbor devices already within the network.

11. A method, comprising:

transmitting one or more unsolicited beacon messages from a device in a frequency hopping communication network;

determining a stability of the communication network; and

adapting an interval of unsolicited beacon message transmission from the device based on stability of the network.

12. The method as in claim 11, wherein adapting based on stability comprises:

in response to expiration of a particular interval, increasing an interval length; and

in response to receiving, from a neighboring device in the communication network, an unsolicited beacon message transmission that contains a different network information version as a pending unsolicited beacon message to be transmitted, decreasing the interval length, and starting a new interval.

13. The method as in claim 11, further comprising:

utilizing a single beacon message to provide network-wide parameters to joining devices and neighbor devices already within the network.

14. A method comprising:

determining an intent to transmit a beacon request from a device in a frequency hopping communication network;

suppressing transmission of the beacon request based on a density-aware redundancy count of other beacon requests from neighboring devices; and

transmitting one or more beacon requests at an adaptive interval, wherein the interval increases in response to each unanswered beacon request.

15. The method as in claim 14, further comprising:

resetting, at a start of a given interval, the redundancy count to 0;

receiving one or more beacon requests from the neighboring devices;

incrementing the redundancy count in response to each received beacon request; and

suppressing beacon request transmission by transmitting a pending beacon request for the given interval if and only if the redundancy count is less than a given threshold value.

16. The method as in claim 14, further comprising:

adapting the interval by increasing the length of the interval up to a configured maximum interval length in response to expiration of a particular interval with an unanswered beacon request.

17. The method as in claim 14, further comprising:

joining the frequency hopping communication network by the device; and

transmitting one or more unsolicited beacon messages from the device based on at least one of either;

i) adapting an interval of unsolicited beacon message transmission from the device based on stability of the network; and

ii) suppressing unsolicited beacon message transmission based on a density-aware redundancy count of other unsolicited beacon message transmissions from neighboring devices in the communication network.

18. An apparatus, comprising:

a processor;

a transceiver configured to communicate in a frequency hopping communication network; and

a memory configured to store at least one process executable by the processor selected from a group consisting of;

A) a first process when executed by the processor operable to transmit one or more responsive beacon messages from the device based on an adaptive type of responsive beacon message transmission based on a number of received beacon requests within a given time period, wherein the number being below a threshold results in synchronized unicast responsive beacon message transmission type, and wherein the number being above the threshold results in unsynchronized broadcast responsive beacon message transmission type;

B) a second process when executed by the processor operable to suppress unsolicited beacon message transmission during a given time period based on a density-aware redundancy count of other unsolicited beacon message transmissions from neighboring devices in the communication network during the given time period; and

C) a third process when executed by the processor operable to transmit one or more unsolicited beacon messages according to an adaptive interval of unsolicited beacon message transmission based on stability of the network.

19. The apparatus as in claim 18, wherein the first process when executed is further operable to, in response to receiving a beacon request when a length of the given time period is not currently set to the minimum length:

set the length of the given time period to the minimum length, and start a new time period as the given time period during which the number of received beacon requests is determined, wherein transmission of the one or more responsive beacon messages is at a particular chosen time prior to expiration of the new time period.

20. The apparatus as in claim 18, wherein second process when executed is further operable to:

reset, at a start of the given time period, the redundancy count to 0;

increment the redundancy count in response to each received unsolicited beacon message containing a same network information version as a pending unsolicited beacon message to be transmitted; and

suppress unsolicited beacon message transmission by transmitting the pending unsolicited beacon message for the given time period if and only if the redundancy count is less than a given threshold value.

21. The apparatus as in claim 18, wherein the third process when executed to adapt the interval is further operable to:

increase a length of the adaptive interval in response to expiration of a particular interval; and

decrease the length of the adaptive interval and start a new interval in response to receiving, from a neighboring device in the communication network, an unsolicited beacon message transmission that contains a different network information version as a pending unsolicited beacon message to be transmitted.

22. The apparatus as in claim 18, wherein the group is further consisting of:

D) a fourth process when executed by the processor operable to suppress transmission of a beacon request to join the communication network based on a density-aware redundancy count of other beacon requests from neighboring devices, and to transmit one or more beacon requests at an adaptive interval, wherein the interval increases in response to each unanswered beacon request.