Wireless communication network including network coordinator assigning time slots and channels to nodes to provide collision-free schedules and data aggregation method for the same

• US 7,830,834 B2
• Filed: 03/22/2007
• Issued: 11/09/2010
• Est. Priority Date: 03/22/2007
• Status: Expired due to Fees

• Current Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Yan, Ting, Pereira, Luis R., Das, Sujit R.
• Primary Examiner(s): Afshar; Kamran
• Assistant Examiner(s): Choo; Munsoon
• Application Number:
  US11/689,544
• Publication Number:
  US 20080232334A1
• Time in Patent Office: 1,328 Days
• Field of Search: 370/337, 370/321, 370/347, 370/254, 370/329, 370/351, 370/356
• US Class Current: 370/329
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A wireless communication network includes a network coordinator (NC) having plural channels and plural wireless transceivers, and plural nodes. Each node has status information, a number of channels and a number of wireless transceivers. Each node and the NC communicate in a Carrier Sense Multiple Access mode. Each node communicates the status information thereof to or toward the NC in a Time Division Multiple Access mode having plural time slots. The NC assigns the time slots and the channels to the nodes to provide a plurality of collision-free schedules therefor. The NC sends, for each node, a corresponding one of the collision-free schedules to or toward a corresponding one of the nodes. Each collision-free schedule includes a corresponding number of the time slots and a corresponding number of the channels that the corresponding one of the nodes employs to communicate the status information thereof to or toward the NC.

Claims

1. A wireless communication network comprising:

a network coordinator comprising a first number of channels and a second number of wireless transceivers; and

a plurality of nodes, each of said nodes comprising status information, a corresponding second number of channels and a corresponding second number of wireless transceivers,

wherein at least some of said nodes are structured to communicate with said network coordinator through multi-hop communication,

wherein said nodes and said network coordinator are structured to communicate in a Carrier Sense Multiple Access mode,

wherein said network coordinator is structured to command said nodes to exit said Carrier Sense Multiple Access mode and enter a Time Division Multiple Access mode.

wherein each of said nodes is structured to communicate the status information thereof to or toward said network coordinator in a Time Division Multiple Access mode,

wherein said Time Division Multiple Access mode has a plurality of time slots,

wherein said network coordinator is structured to assign said time slots and said channels to said nodes in order to provide a plurality of collision-free schedules for said nodes in said Time Division Multiple Access mode, and

wherein said network coordinator is further structured to send, for each of said nodes, a corresponding one of said collision-free schedules to or toward a corresponding one of said nodes, said corresponding one of said collision-free schedules including a corresponding number of said time slots and a corresponding number of said channels that the corresponding one of said nodes employs to communicate the status information thereof to or toward said network coordinator in said Time Division Multiple Access mode.

2. The wireless communication network of claim 1 wherein said network coordinator is further structured to command said nodes to exit said Carrier Sense Multiple Access mode and enter said Time Division Multiple Access mode.

3. The wireless communication network of claim 1 wherein at least one of said nodes is a parent node;

wherein at least one of said nodes is a child node of said parent node;

wherein said child node is structured to communicate the status information of said child node to said parent node in a first one of said time slots in said Time Division Multiple Access mode; and

wherein said parent node is structured to communicate the status information of said child node to or toward said network coordinator in a second one of said time slots after said first one of said time slots in said Time Division Multiple Access mode.

4. The wireless communication network of claim 1 wherein at least one of said nodes is a parent node;

wherein a plurality of said nodes are child nodes of said parent node;

wherein a first one of said child nodes is structured to communicate the status information of said first one of said child nodes to said parent node in a corresponding first one of said time slots in said Time Division Multiple Access mode;

wherein a different second one of said child nodes is structured to communicate the status information of said different second one of said child nodes to said parent node in a corresponding different second one of said time slots in said Time Division Multiple Access mode; and

wherein said parent node is structured to communicate the status information of said child nodes to or toward said network coordinator in a third one of said time slots after said first one and said different second one of said time slots in said Time Division Multiple Access mode.

5. The wireless communication network of claim 1 wherein at least one of said nodes is a parent node;

wherein a plurality of said nodes are child nodes of said parent node;

wherein a first one of said child nodes is structured to communicate the status information of said first one of said child nodes to said parent node using a first one of said channels in a first one of said time slots in said Time Division Multiple Access mode;

wherein a different second one of said child nodes is structured to communicate the status information of said different second one of said child nodes to said parent node using a different second one of said channels in the first one of said time slots in said Time Division Multiple Access mode; and

wherein said parent node is structured to communicate the status information of said child nodes to or toward said network coordinator in a different second one of said time slots after said first one of said time slots in said Time Division Multiple Access mode.

6. The wireless communication network of claim 5 wherein said parent node comprises the first one of said channels, the second one of said channels, a first one of said wireless transceivers and a second one of said wireless transceivers;

wherein said parent node is further structured to receive the status information of said first one of said child nodes using the first one of said channels and the first one of said transceivers, and to contemporaneously receive the status information of said different second one of said child nodes using the second one of said channels and the second one of said transceivers.

7. The wireless communication network of claim 1 wherein at least one of said nodes is a parent node;

wherein a plurality of said nodes are child nodes of said parent node;

wherein said first number of channels is a plurality of channels and said first number of wireless transceivers is a plurality of wireless transceivers;

wherein the corresponding second number of channels is a second plurality of channels and the corresponding second number of wireless transceivers is a second plurality of wireless transceivers;

wherein each of said child nodes is structured to communicate the status information thereof to said parent node using either;

the same one of said time slots in said Time Division Multiple Access mode and different ones of said second channels, or different ones of said time slots in said Time Division Multiple Access mode and the same one of said second channels.

8. The wireless communication network of claim 1 wherein said network coordinator is structured to provide a commissioning phase in which said network coordinator builds a spanning tree including a plurality of edges, causes time synchronization among the nodes, calculates said collision-free schedules, and communicates said collision-free schedules;

and wherein each of said edges has a child node of said nodes and a parent node of said nodes.

9. The wireless communication network of claim 1 wherein said network coordinator is structured to build a spanning tree including a plurality of edges, a plurality of branches, a plurality of child nodes of said nodes and a plurality of parent nodes of said nodes;

wherein each of said branches includes a number of said child nodes; and

wherein said network coordinator first calculates one of said collision-free schedules for one of said branches having the largest count of said child nodes.

10. The wireless communication network of claim 1 wherein said network coordinator is structured to build a spanning tree including a plurality of edges, a plurality of branches, a plurality of child nodes of said nodes and a plurality of parent nodes of said nodes;

wherein a first plurality of said branches defines a first multi-hop communication path from a first one of said child nodes to one of said parent nodes to or toward said network coordinator;

wherein a second plurality of said branches defines a second multi-hop communication path from a different second one of said child nodes to one of said parent nodes to or toward said network coordinator; and

wherein said network coordinator first calculates a first plurality of said collision-free schedules for the first multi-hop communication path before said network coordinator calculates a second plurality of said collision-free schedules for the second multi-hop communication path.

11. A data aggregation method for a wireless communication network including a plurality of nodes, said nodes including a network coordinator, a plurality of child nodes and a plurality of parent nodes, said method comprising:

defining a network topology of a plurality of pairs of said child nodes and said parent nodes in said wireless communication network, each of said pairs including one of said child nodes and one of said parent nodes;

at said network coordinator, collecting network topology information from said wireless communication network and assigning a plurality of time slots and a number of channels to said nodes in order to provide a plurality of collision-free schedules for all of said nodes;

for each of said child nodes and said parent nodes, sending a corresponding collision-free schedule from said network coordinator to or toward a corresponding one of said child nodes and said parent nodes;

including, with said corresponding collision-free schedule, a corresponding time slot and a corresponding channel that the corresponding one of said child nodes and said parent nodes employs to send status information to or toward said network coordinator; and

for each of said child nodes and said parent nodes, starting at the corresponding time slot, sending said status information to or toward said network coordinator on the corresponding channel.

12. The method of claim 11 further comprising communicating a number of commands from said network coordinator to or toward said nodes in a Carrier Sense Multiple Access mode.

13. The method of claim 11 further comprising building an address tree topology in order that said network coordinator is the root of said address tree topology and said child nodes and said parent nodes are descendants of said network coordinator;

employing a first constraint whereby each of said parent nodes cannot send the status information to or toward said network coordinator until each of said parent nodes receives the status information from all of its child nodes; and

employing a second constraint whereby none of said pairs can send the status information simultaneously over the same one of said channels.

14. The method of claim 13 further comprising employing a third constraint as being a maximum count of said channels;

employing a fourth constraint as being a maximum count of radio transceivers for said wireless communication network; and

employing a fifth constraint as being a maximum count of the radio transceivers for each of said child nodes and said parent nodes.

15. The method of claim 14 further comprising employing a sixth constraint as being a maximum time for the network coordinator to receive all of the status information from said child nodes and said parent nodes.

16. The method of claim 11 further comprising building a spanning tree including a plurality of edges at said network coordinator, each of said edges including one of said child nodes and one of said parent nodes;

synchronizing time at each of the nodes;

calculating said corresponding collision-free schedules at said network coordinator; and

communicating said calculated corresponding collision-free schedules from said network coordinator to or toward said parent nodes and said child nodes.

17. The method of claim 11 further comprising for some of said collision-free schedules, assigning a plurality of said time slots to a number of said child nodes and said parent nodes.

18. The method of claim 11 further comprising for a number of said collision-free schedules and for a number of said time slots, assigning a number of redundant empty time slots.

19. The method of claim 11 further comprising for some of said collision-free schedules, dynamically selecting a plurality of said channels on the basis of communication link qualities.

20. The method of claim 11 further comprising employing a total count of said time slots for said collision-free schedules as being less than or equal to about ten plus a count of said child nodes and said parent nodes divided by a count of said number of channels.

21. The method of claim 11 further comprising employing a count of said plurality of nodes of about 500 to about 1000.

22. The method of claim 11 further comprising predefining a plurality of extra wireless transceivers;

and

assigning said extra wireless transceivers to a number of said nodes and, otherwise, employing a single wireless transceiver at each of the others of said nodes.

23. The method of claim 11 further comprising synchronizing time between said network coordinator and said nodes in a Carrier Sense Multiple Access mode.

24. A wireless communication network comprising:

a network coordinator comprising a first number of channels and a second number of wireless transceivers; and

a plurality of nodes, each of said nodes comprising status information, a corresponding second number of channels and a corresponding second number of wireless transceivers,

wherein at least some of said nodes are structured to communicate with said network coordinator through multi-hop communication,

wherein said nodes and said network coordinator are structured to communicate in a Carrier Sense Multiple Access mode,

wherein said network coordinator is structured to command said nodes to exit said Carrier Sense Multiple Access mode and enter a Time Division Multiple Access mode,

wherein each of said nodes is structured to communicate the status information thereof to or toward said network coordinator in said Time Division Multiple Access mode,

wherein said Time Division Multiple Access mode has a plurality of time slots, and

wherein said network coordinator is structured to assign said time slots and said channels to said nodes in order to provide a plurality of collision-free schedules for said nodes in said Time Division Multiple Access mode.