Wireless mesh network with multisized timeslots for TDMA communication

• US 20080084852A1
• Filed: 09/28/2007
• Published: 04/10/2008
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Karschnia, Robert
• Granted Patent: US 8,005,020 B2
• Time in Patent Office: Days
• US Class Current: 370/337
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04J 3/1682 Allocation of channels according to the instantaneous demands of the users, e.g. concentrated multiplexers, statistical multiplexers
• CPC Class Codes: H04W 72/51 based on terminal or device properties
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A wireless mesh network uses communication frames that can include timeslots of different sizes depending on communication speed capabilities of the devices assigned to the timeslots. The communication frame is divided into timeslot increments of equal length. The timeslots are made up of one or more timeslot increments.

Claims

1. A method of operating a wireless mesh network having a plurality of nodes capable of transmitting and receiving messages, the method comprising:

synchronizing the nodes to a communication cycle having a frame formed by a plurality of equal length timeslot increments; and

assigning timeslots within each frame for communication between nodes, each timeslot made up of one or more timeslot increments based upon communication speed capabilities of the nodes assigned to that timeslot.

2. The method of claim 1, wherein each of the timeslot increments has a time duration less than or equal to a shortest expected timeslot to be used by the network.

3. The method of claim 1, wherein the frame has a time duration T_f=Nt_i, where t_i is a time duration of each of the timeslot increments and N is a number of timeslot intervals in the frame.

4. The method of claim 3, wherein the frame includes at least one timeslot of a duration of t_i.

5. The method of claim 3, wherein the frame includes at least one timeslot of a duration of 2 t_i.

6. The method of claim 3, wherein the frame includes at least one timeslot of a duration of 4 t_i.

7. The method of claim 1, wherein assigning timeslots is based upon stored configuration data for each node.

8. The method of claim 7, wherein the stored configuration data includes a minimum time period required by the node to communicate during a timeslot.

9. A wireless mesh network comprising a plurality of nodes capable of transmitting and receiving messages during assigned timeslots within a repeating communication frame, characterized by:

the frame comprising N timeslot increments of time duration t_i; and

each timeslot has a time duration Mt_i, where M is a positive integer less than N, and wherein the time duration of each timeslot is determined based upon a minimum time required by each node assigned to that timeslot to communicate.

10. The wireless mesh network of claim 9, wherein the frame includes at least one timeslot having a time duration of t_i.

11. The wireless mesh network of claim 9, wherein the frame includes at least one timeslot having a time duration of 2 t_i.

12. The wireless mesh network of claim 9, wherein the frame includes at least one timeslot having a time duration of 4 t_i.

13. The wireless mesh network of claim 9, wherein the frame includes timeslots of different time durations.

14. The wireless mesh network of claim 9 and further comprising:

a network manager that assigns selected nodes to the timeslots and determines the time duration of each timeslot.

15. The wireless mesh network of claim 14, wherein the network manager uses stored configuration data for the nodes to determine the time durations of the timeslots.

16. A wireless mesh network comprising;

a plurality of nodes capable of transmitting and receiving messages; and

a network manager for synchronizing the nodes based upon a communication cycle of repeating frames, wherein each frame includes timeslots assigned to selected nodes, and wherein the network manager can assign timeslots different time durations depending on capabilities of the selected nodes.

17. The wireless mesh network of claim 16, wherein the frame comprises N timeslot increments of time duration t_i, and wherein each timeslot has a time duration Mt_i, where M is a positive integer.

18. The wireless mesh network of claim 17, wherein the network manager determines the time duration of each timeslot based upon a minimum time required by the selected nodes to communicate during that timeslot.

19. The wireless mesh network of claim 17, wherein the frame includes at least one timeslot of time duration 2 t_i.

20. The wireless mesh network of claim 17, wherein the frame includes at least one timeslot of time duration 4 t_i.