System and method for slaves in a master-slave wireless network to dynamically develop affinity to a time slot

• US 20070080788A1
• Filed: 10/12/2005
• Published: 04/12/2007
• Est. Priority Date: 10/12/2005
• Status: Abandoned Application

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: VanVoorst, Brian, Becker, Robert, Manley, Jathan
• Application Number:
  US11/248,120
• Publication Number:
  US 20070080788A1
• Time in Patent Office: Days
• US Class Current: 340/10.330
• CPC Class Codes: H04W 74/06 using polling
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A method to dynamically schedule communication between a master and slaves in a variable slave population in a master-slave wireless network. The method includes receiving a first interrogation phase command signal from the master, transmitting a response signal to the master responsive to the first interrogation phase command signal after a current time interval, the current time interval based on a current time slot selection, receiving an acknowledgment list from the master responsive to the transmitted response signal, determining whether the current time slot selection matches a master-filled time slot based on the acknowledgement list, and modifying an affinity value based on the determination.

Claims

1. A method to dynamically schedule communication between a master and slaves in a variable slave population in a master-slave wireless network, the method comprising:

receiving a first interrogation phase command signal from the master;

transmitting a response signal to the master responsive to the first interrogation phase command signal after a current time interval, the current time interval based on a current time slot selection;

receiving an acknowledgement list from the master responsive to the transmitted response signal;

determining whether the current time slot selection matches a master-filled time slot based on the acknowledgement list; and

modifying an affinity value based on the determination.

2. The method of claim 1, wherein the current time slot selection is an initial time slot selection, the method further comprising:

setting the affinity value equal to an affinity threshold value.

3. The method of claim 2, wherein the affinity threshold value is one.

4. The method of claim 1, wherein modifying the affinity value comprises:

reducing the affinity value if the determination is negative; and

setting the affinity value to a pre-established maximum affinity value if the determination is positive.

5. The method of claim 4, wherein reducing the affinity value comprises:

reducing the affinity value by an affinity reducing value;

determining the affinity value is not less than the affinity threshold value;

determining the master is not transmitting a second interrogation phase command signal; and

waiting to receive the first interrogation phase command signal from the master.

6. The method of claim 4, wherein reducing the affinity comprises:

reducing the affinity value by an affinity reducing value;

determining the affinity value is not less than an affinity threshold value;

receiving a second interrogation phase command signal from the master;

transmitting a response signal to the master responsive to the second interrogation phase command signal; and

receiving an acknowledgement list from the master responsive to the latest response signal.

7. The method of claim 6, wherein a duration of a second interrogation phase is shorter than a duration of a first interrogation phase.

8. The method of claim 4, wherein reducing the affinity value comprises:

reducing the affinity value by an affinity reducing value determining the affinity value is less than an affinity threshold value;

modifying the current time slot selection;

setting the affinity value equal to the affinity threshold value;

determining the master is not transmitting a second interrogation phase command signal; and

waiting to receive the first interrogation phase command signal from the master.

9. The method of claim 8, wherein a duration of a second interrogation phase is shorter than a duration of a first interrogation phase.

10. The method of claim 9, wherein receiving an acknowledgement list from the master responsive to the transmitted response signal comprises:

receiving a mapping matrix from the master, wherein the mapping matrix correlates a list of unused time slots to a list of all time slots, and wherein the duration of the second interrogation phase is correlated to the list of unused time slots;

selecting the current time slot from one of a column or a row of the mapping matrix;

determining the current time slot selection matches the master-filled time slot based on an acknowledgement list from the master responsive to the latest response signal;

mapping the current time slot to the list of all time slots; and

selecting the current time slot from the list of all time slots based on the mapping.

11. The method of claim 8, wherein modifying the current time slot selection is selected from the group comprising at least one of:

randomly selecting a new time slot from a list of all time slots;

applying a selection algorithm to the list of all time slots;

randomly selecting the current time slot from a list of unused time slots;

applying a selection algorithm to the list of unused time slots;

randomly selecting a time slot from the list of unused time slots and mapping the time slot to the list of all time slots; and

applying the selection algorithm to the list of unused time slots and mapping the time slot to the list of all time slots.

12. The method of claim 4, wherein reducing the affinity value comprises:

reducing the affinity value by an affinity reducing value;

determining the affinity value is less than an affinity threshold value;

modifying the current time slot selection;

setting the affinity value equal to the affinity threshold value;

receiving a second interrogation phase command signal from the master;

transmitting a response signal to the master responsive to the second interrogation phase command signal after the current time interval; and

receiving an acknowledgement list from the master responsive to the latest response signal.

13. The method of claim 12, wherein a duration of a second interrogation phase is shorter than a duration of a first interrogation phase.

14. The method of claim 13, receiving an acknowledgement list from the master responsive to the transmitted response signal comprises:

receiving a mapping matrix from the master, wherein the mapping matrix correlates a list of unused time slots to a list of all time slots, and wherein the duration of the second interrogation phase is correlated to the list of unused time slots;

selecting the current time slot from one of a column or a row of the mapping matrix;

determining the current time slot selection matches the master-filled time slot based on an acknowledgement list from the master responsive to the latest response signal;

mapping the current time slot from the list of unused time slots to the list of all time slots; and

selecting the current time slot from the list of all time slots based on the mapping.

15. The method of claim 12, wherein modifying the current time slot selection is selected from the group comprising:

at least one of randomly selecting the current time slot selection from a list of all time slots;

applying a selection algorithm to the list of all time slots;

randomly selecting the current time slot selection from a list of unused time slots;

applying a selection algorithm to the list of unused time slots;

randomly selecting a time slot from the list of unused time slots and mapping the time slot to the list of all time slots; and

applying a selection algorithm to the list of unused time slots and mapping the time slot to the list of all time slots.

16. The method of claim 1, wherein the master is a radio frequency identification reader and the slave is a radio frequency identification tag.

17. The method of claim 1, wherein the acknowledgement list is selected from the group comprising at least one of a list of master-filled time slots, a list of master-open time slots, a list of receive-failed time slots, a list of master-contended time slots, a list of master-quiet time slots.

18. The method of claim 1, wherein the first interrogation phase command signal initiates a first interrogation phase in an interrogation event and a second interrogation phase command signal initiates a second interrogation phase in the interrogation event, and wherein the second interrogation phase is of shorter duration than the first interrogation phase.

19. The method of claim 18, wherein subsequent interrogations phases follow the second interrogation phase until the all time slots in an acknowledgment list are master-filled time slots, and wherein each subsequent interrogation phase is of shorter duration than the previous interrogation phase.

20. A system to dynamically schedule communication between a master and a slave in a variable slave population in a master-slave wireless network, comprising:

means for determining an initial time slot selection for the slave;

means for establishing an affinity value for the slave;

means for establishing a current time slot selection for the slave; and

means for dynamically re-establishing the affinity value and the current time slot selections for the slave as the slave population changes.

21. The system of claim 20, the system further comprising:

means for mapping a list of unused time slots to a list of all time slots; and

means for modifying a current time slot selection based on the mapping.

22. A computer readable medium storing a computer program comprising:

computer readable code for receiving a first interrogation phase command signal from the master;

computer readable code for transmitting a response signal to the master after a current time interval;

computer readable code for receiving an acknowledgement list from the master;

computer readable code for determining whether the current time slot selection matches a master-filled time slot; and

computer readable code for modifying an affinity value based on the determination.

23. The medium of claim 22, further comprising:

computer readable code for generating a mapping matrix wherein the mapping matrix correlates a list of unused time slots to a list of all time slots;

computer readable code for selecting the current time slot from one of a column or a row of the mapping matrix;

computer readable code for determining the current time slot selection matches the master-filled time slot based on an acknowledgement list from the master responsive to the latest response signal;

computer readable code for mapping the current time slot from the list of unused time slots to the list of all time slots; and

computer readable code for selecting the current time slot from the list of all time slots based on the mapping.

24. The medium of claim 22, wherein the current time slot is an initial time slot selection, the medium further comprising:

setting the affinity value equal to an affinity threshold value.

25. The medium of claim 22, wherein computer readable code for modifying the affinity value comprises:

computer readable code for reducing the affinity value if the determination is negative; and

computer readable code for setting the affinity value to a pre-established maximum affinity value if the determination is positive.

26. The medium of claim 25, wherein computer readable code for reducing the affinity value comprises:

computer readable code for reducing the affinity value by an affinity reducing value;

computer readable code for determining the affinity value is not less than an affinity threshold value;

computer readable code for determining the master is not transmitting a second interrogation phase command signal; and

computer readable code for waiting to receive a first interrogation phase command signal from the master.

27. The method of claim 25, wherein computer readable code for reducing the affinity value comprises:

computer readable code for reducing the affinity value by an affinity reducing value;

computer readable code for determining the affinity value is not less than an affinity threshold value;

computer readable code for receiving a second interrogation phase command signal from the master;

computer readable code for transmitting a response signal to the master responsive to the second interrogation phase command signal; and

computer readable code for receiving an acknowledgement list from the master responsive to the latest response signal.

28. The medium of claim 25, wherein computer readable code for reducing the affinity value comprises:

computer readable code for reducing the affinity value by an affinity reducing value;

computer readable code for determining the affinity value is less than an affinity threshold value;

computer readable code for modifying the current time slot selection;

computer readable code for setting the affinity value equal to the affinity threshold value;

computer readable code for determining the master is not transmitting a second interrogation phase command signal; and

computer readable code for waiting to receive a first interrogation phase command signal from the master.

29. The medium of claim 25, wherein computer readable code for reducing the affinity value comprises:

computer readable code for reducing the affinity value by an affinity reducing value;

computer readable code for determining the affinity value is less than an affinity threshold value;

computer readable code for modifying the current time slot selection;

computer readable code for setting the affinity value equal to the affinity threshold value;

computer readable code for receiving a second interrogation phase command signal from the master;

computer readable code for transmitting a response signal to the master responsive to the second interrogation phase command signal; and

computer readable code for receiving an acknowledgement list from the master responsive to the latest response signal.