Method and apparatus of prioritising the usage of slotted links by single network devices in a wireless network

1. A method for determining a contact slot for communication between device in a slotted communication system, the method comprising:

identifying a current slot number of a slotted communication system at a first device;

determining a first value of a first parameter at the first device, the first parameter defining a distance between contact slots for communicating with a second device;

determining a second value of a second parameter at the first device, the second parameter defining an offset distance from a start of a contact slot for communicating with the second device;

determining a next contact slot for communicating with the second device, wherein the next contact slot is a smallest slot number after the identified current slot number that satisfies N slot mod N inter — contact =N contact — offset where N slot is the smallest slot number after the identified current slot number, N inter — contact is the determined first value, and N contact — offset is the determined second value; and

communicating with the second device at a contact time based on the determined next contact slot.

2. The method of claim 1 , further comprising determining a third value of a third parameter at the first device, the third parameter defining a backoff counter for communicating with the second device, wherein the next contact slot is determined based on N slot mod 2 b N inter — contact =N contact — offset where b is the determined third value.

3. The method of claim 1 , further comprising adjusting the determined third value unless 2 b N inter — contact >N max — poll where N max — poll is a maximum number of slots to allow since a last successful contact event.

4. The method of claim 1 , further comprising adjusting the determined first value based on a priority of the communication with the second device.

5. The method of claim 4 , wherein the determined first value is adjusted by a factor of 2.

6. The method of claim 4 , wherein the determined first value is adjusted based on a time period since a last successful contact event.

7. The method of claim 4 , further comprising increasing the priority of the communication with the second device if a third device is no longer communicating with the first device.

8. The method of claim 4 , further comprising increasing the priority of the communication with the second device up to a maximum priority value.

9. The method of claim 4 , further comprising increasing the priority of the communication with the second device after a time since a last successful contact event exceeds a maximum value.

10. A method for redistributing slots for communication between devices in a slotted communication system, the method comprising:

identifying an occurrence of a redistribution event at a first device;

identifying a priority of a current communication link of a plurality of communication links between the first device and a plurality of devices;

determining a first value of a first parameter at the first device, the first parameter defining a lowest priority associated with the plurality of communication links;

determining a number of slots to redistribute among the plurality of communication links, wherein the number of slots is calculated as (S current −S min )*(n−1)/n where S current is the identified priority, S min is the determined first value, and n is the number of the plurality of communication links; and

redistributing the determined number of slots among the plurality of communication links.

11. The method of claim 10 , wherein the redistribution event is indicated by sending an ABORT packet to the second device.

12. The method of claim 10 , wherein the redistribution event is indicated by sending a NULL packet to the second device.

13. The method of claim 12 , wherein the redistribution event is further indicated by receiving a second NULL packet from the second device.

14. The method of claim 10 , wherein the redistribution event is indicated by not receiving a communication from a second device of the plurality of devices within a timeout period.

15. The method of claim 10 , wherein the redistribution event is indicated by communicating with a second device at a contact time instead of a third device based on a priority of a communication with the second device relative to a second priority of a second communication with a third device.

16. The method of claim 15 , wherein the redistribution event is further indicated by sending an ABORT packet to the third device.

17. A device comprising:

means for identifying a current slot number of a slotted communication system;

means for determining a first value of a first parameter, the first parameter defining a distance between contact slots for communicating with a second device;

means for determining a second value of a second parameter, the second parameter defining an offset distance from a start of a contact slot for communicating with the second device;

means for determining a next contact slot for communicating with the second device, wherein the next contact slot is a smallest slot number after the identified current slot number that satisfies N slot mod N inter — contact =N contact — offset where N slot is the smallest slot number after the identified current slot number, N inter — contact is the determined first value, and N contact — offset is the determined second value; and

means for communicating with the second device at a contact time based on the determined next contact slot.

18. The device of claim 17 , further comprising means for determining a third value of a third parameter, the third parameter defining a backoff counter for communicating with the second device, wherein the next contact slot is determined based on N slot mod 2 b N inter — contact =N contact — offset where b is the determined third value.

19. The device of claim 17 , further comprising means for adjusting the determined third value unless 2 b N inter — contact >N max — poll where N max — poll is a maximum number of slots to allow since a last successful contact event.

20. The device of claim 17 , further comprising means for adjusting the determined first value based on a priority of the communication with the second device.

21. The device of claim 20 , wherein the determined first value is adjusted by a factor of 2.

22. The device of claim 20 , wherein the determined first value is adjusted based on a time period since a last successful contact event.

23. The device of claim 20 , further comprising means for increasing the priority of the communication with the second device if a third device is no longer communicating with the device.

24. The device of claim 20 , further comprising means for increasing the priority of the communication with the second device up to a maximum priority value.

25. The device of claim 20 , further comprising means for increasing the priority of the communication with the second device after a time since a last successful contact event exceeds a maximum value.

26. A device, the device comprising:

means for identifying an occurrence of a redistribution event;

means for identifying a priority of a current communication link of a plurality of communication links between the device and a plurality of devices;

means for determining a first value of a first parameter, the first parameter defining a lowest priority associated with the plurality of communication links;

means for determining a number of slots to redistribute among the plurality of communication links, wherein the number of slots is calculated as (S current −S min )*(n−1)/n where S current is the identified priority, S min is the determined first value, and n is the number of the plurality of communication links; and

means for redistributing the determined number of slots, among the plurality of communication links.

27. The device of claim 26 , wherein the redistribution event is indicated by sending an ABORT packet to the second device.

28. The device of claim 26 , wherein the redistribution event is indicated by sending a NULL packet to the second device.

29. The device of claim 28 , wherein the redistribution event is further indicated by receiving a second NULL packet from the second device.

30. The device of claim 26 , wherein the redistribution event is indicated by not receiving a communication from a second device of the plurality of devices within a timeout period.