Method and apparatus for wireless communication in a mesh network using frequency schedule

• US 8,892,135 B2
• Filed: 07/12/2007
• Issued: 11/18/2014
• Est. Priority Date: 07/17/2003
• Status: Active Grant

• Current Assignee: Honeywell International SARL (Honeywell International Inc.), Yokogawa USA, Inc. (Yokogawa Electric Corporation)
• Original Assignee: Honeywell International SARL (Honeywell International Inc.), Yokogawa USA, Inc. (Yokogawa Electric Corporation)
• Inventors: Werb, Jay Philip, Berry, Victor A., Weiss, Howard P., Lamb, C. Scott
• Primary Examiner(s): Vu, Michael T
• Application Number:
  US11/776,938
• Publication Number:
  US 20140286301A1
• Time in Patent Office: 2,686 Days
• Field of Search: 455/462, 455/445, 455/500, 455/422, 455/425, 455/428, 455/502, 455/351, 455/254, 370/328, 370/338, 370/351, 370/252, 370/254, 370/314, 370/445, 370/310
• US Class Current: 455/462
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/16 the keys or algorithms being changed during operation
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04W 12/069 using certificates or pre-shared keys
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0219 where the power saving management affects multiple terminals
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and apparatus for communication in a wireless sensor network. In one embodiment, one or more routers in a network may be available for communication with one or more star nodes at a randomized time and/or frequency. A connectivity assessment, which may be performed at several different frequencies and/or times, may be performed to evaluate the quality of communications between devices in the network. Primary and secondary communication relationships may be formed between devices to provide for system redundancy. One or more proxies may be maintained where each proxy includes a status of one or more devices in the network, e.g., one or more star nodes or routers. Proxies may be used to handle information requests and/or status change requests, e.g., a proxy may be requested to change a communication relationship between devices in the network and may generate command signals to cause the corresponding devices to make the change.

Claims

1. A mesh network comprising:

multiple nodes including a plurality of star nodes and a plurality of routing nodes, each star node configured to transmit and receive wireless signals, each routing node configured to transmit and receive wireless signals for communication with at least one of the star nodes;

wherein each star node is configured to communicate with at least one of the routing nodes using a plurality of different frequencies; and

wherein each routing node is configured to become available for communication with at least one of the star nodes based on a time and frequency schedule that is coordinated between multiple ones of the routing nodes and at least one of the star nodes;

wherein the coordinated time and frequency schedule defines at least one randomized sequence of different frequencies used; and

wherein the coordinated time and frequency schedule is coordinated with other routing nodes and indicates a start time for each frequency.

2. The network of claim 1, wherein each routing node is configured to communicate with at least one other of the routing nodes using a plurality of different frequencies.

3. The network of claim 2, wherein each routing node is configured to become available for communication with at least one other of the routing nodes for a period that begins at least one of:

at a randomized time or at a randomized frequency.

4. The network of claim 1, further comprising:

at least one gateway; and

a host computer;

wherein at least two of the routing nodes are configured to communicate with the host computer via the at least one gateway.

5. The network of claim 4, wherein at least one of the routing nodes is configured to communicate with the host computer via at least one other of the routing nodes.

6. The network of claim 1, wherein at least one of the star nodes has a sleep cycle that is controlled such that the at least one star node wakes up for communication with one or more of the routing nodes at a time that approximately coincides with a period when the one or more routing nodes are available for communication.

7. The network of claim 1, wherein each routing node is configured to transmit a beacon before at least one period during which the routing node is available for communication with at least one of the star nodes.

8. The network of claim 7, wherein the beacon includes one or more of:

a PHY header, a MAC header, a network identification number, a session identifier, a router identifier, a current time, a last time that network parameters changed, information for determining a dither, information for determining a currently active communication channel, or a list of children with store-and-forward messages in a queue.

9. The network of claim 1, wherein at least one of the routing nodes is configured to change a length of a time period during which the at least one routing node is available for communication with at least one of the star nodes based on an amount of network traffic.

10. The network of claim 1, wherein at least one of the routing nodes is configured to enter a low-power sleep mode between multiple periods during which the at least one routing node is available for communication with at least one of the star nodes.

11. The network of claim 1, wherein at least one of the routing nodes is configured to become available for communication with at least one of the star nodes during a period that starts at the start time determined based on at least one of:

a linear congruential generator or a table lookup.

12. The network of claim 1, wherein at least one of the star nodes is configured to retransmit a signal using a second frequency upon failure to receive a MAC-level acknowledgement after sending the signal using a first frequency.

13. The network of claim 1, wherein each of at least one of the star nodes is configured to resynchronize its clock with that of one of the routing nodes by sending a communication to that routing node and receiving an acknowledgment of the communication from that routing node, the acknowledgement including time synchronization information.

14. The network of claim 1, wherein each of at least one of the star nodes is configured to resynchronize its clock with that of one of the routing nodes by listening for a beacon sent by that routing node around a scheduled time when that routing node is to send the beacon.

15. The network of claim 1, wherein each of at least one of the multiple nodes is adapted to calibrate its clock based on detecting clock drift of its clock in relation to another clock source.

16. The network of claim 15, wherein each of at least one of the multiple nodes is configured to detect clock drift between two or more time synchronization points with a parent node.

17. The network of claim 1, wherein each star node is configured to perform a connectivity assessment for at least one device in the mesh network, the connectivity assessment indicating a measure of quality of wireless communication between each star node and the at least one device.

18. The network of claim 17, wherein:

the at least one device in the mesh network comprises a first device and a second device; and

if a communication between a specified star node and the first device at a first frequency is not acknowledged, the specified star node is configured to attempt a communication with the second device at a second frequency.

19. The network of claim 18, wherein the specified star node is configured to perform the connectivity assessment for each of the first and second devices at multiple frequencies.

20. The network of claim 1, wherein the schedule indicates a length of time each frequency is to be used.

21. An apparatus comprising:

a routing node comprising a wireless radio configured to communicate with one or more of multiple nodes in a mesh network including at least one of one or more star nodes and one or more other routing nodes, each star node configured to transmit and receive wireless signals using a plurality of different frequencies, each routing node configured to transmit and receive wireless signals for communication with at least one of the star nodes;

wherein the routing node is configured to become available for communication with at least one of the star nodes based on a time and frequency schedule that is coordinated between multiple ones of the routing nodes and at least one of the star nodes;

wherein the coordinated time and frequency schedule defines at least one randomized sequence of different frequencies used; and

wherein the coordinated time and frequency schedule is coordinated with other routing nodes and indicates a start time for each frequency.

22. A method comprising:

communicating, at a routing node, with one or more of multiple nodes in a mesh network including at least one of;

one or more star nodes and one or more other routing nodes, each star node configured to transmit and receive wireless signals using a plurality of different frequencies, each routing node configured to transmit and receive wireless signals for communication with at least one of the star nodes;

wherein the communicating comprises, at the routing node, becoming available for communication with at least one of the star nodes based on a time and frequency schedule that is coordinated between multiple ones of the routing nodes and at least one of the star nodes;

wherein the coordinated time and frequency schedule defines at least one randomized sequence of different frequencies used; and

wherein the coordinated time and frequency schedule is coordinated with other routing nodes and indicates a start time for each frequency.