PROTOCOL FOR RELIABLE, SELF-ORGANIZING, LOW-POWER WIRELESS NETWORK FOR SECURITY AND BUILDING AUTOMATION SYSTEMS

• US 20090103456A1
• Filed: 12/29/2008
• Published: 04/23/2009
• Est. Priority Date: 01/10/2002
• Status: Active Grant

• Current Assignee: Arati Manjeshwar, Falk Herrmann, Jason Hill
• Original Assignee: Arati Manjeshwar, Falk Herrmann, Jason Hill
• Inventors: Herrmann, Falk, Hill, Jason, Manjeshwar, Arati
• Granted Patent: US 8,194,571 B2
• Time in Patent Office: Days
• US Class Current: 370/254
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H04L 12/2803 Home automation networks
• CPC Class Codes: H04L 12/2827 Reporting to a device within the home network; wherein the reception of the information reported automatically triggers the execution of a home appliance functionality
• CPC Class Codes: H04Q 2209/883 where the sensing device enters an active or inactive mode
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
• 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 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0245 according to signal strength
• 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 to wirelessly network a sensor/actuator node is described. The sensor/actuator node is installed in a sensor/actuator node network and arranged in a hierarchical manner with a plurality of node levels and a cluster head network. A unique node identifier is assigned to the sensor node and the sensor node network is initialized. The sensor node is woken-up to perform a task and then set to an active low power mode.

Claims

1. A method for initializing a sensor node network arranged in a hierarchical manner with a plurality of node levels and a cluster head network, comprising:

establishing a temporary topology and synchronizing the sensor node network;

discovering and assessing at least one link of the sensor node network; and

registering a sensor node of the sensor node network with a cluster head of the cluster head network.

2. The method according to claim 1, wherein the step of establishing the temporary topology and synchronizing further includes:

broadcasting a wakeup signal from a lower level node to a higher level node;

transmitting an initialization packet from the lower level node to the higher level node;

synchronizing the higher level node;

transmitting a temporary registration packet from the higher level node to the lower level node; and

repeating the steps of broadcasting the wakeup signal, transmitting the initialization packet;

synchronizing, and transmitting the temporary registration packet until one of all nodes have been reached and all nodes up to a predefined level have been reached.

3. The method of claim 2, wherein the lower level node is the cluster head and the high level node is a first level sensor node.

4. The method of claim 2, wherein the lower level node is a first level node and the higher level node is a second level node.

5. The method of claim 2, wherein the higher level node is an upper limit level node.

6. The method of claim 1, wherein the step of discovering and assessing further includes:

broadcasting a plurality of link assessment packets.

7. The method of claim 6, wherein the link assessment packets are broadcast in a fully randomized manner.

8. The method of claim 6, wherein the link assessment packets are broadcast in a time-slotted randomized/deterministic manner.

9. The method of claim 8, wherein a broadcast period is divided into a time slot for each level of the sensor node network.

10. The method of claim 9, wherein the broadcast occurs only within a small fraction of the time slot.

11. The method of claim 9, wherein the broadcast occurs randomly with the time slot.

12. The method of claim 9, wherein the broadcast occurs based on a unique identifier associated with the sensor node.

13. The method of claim 9, wherein the broadcast occurs based on a code to ensure that any two node interfere at most in only one time slot.

14. The method of claim 1, wherein the step of registration further includes:

forwarding a plurality of registration packets.

15. The method of claim 14, wherein the registration packets are forwarded in randomized individual node approach.

16. The method of claim 14, wherein the registration packets are forwarded in a time-slotted level-wise approach.

17. The method of claim 16, wherein a broadcast period is divided into a time slot for each level of the sensor node network.

18. The method of claim 17, wherein a broadcast order for the each level includes a higher to lower order.

19. The method of claim 14, wherein registration data from higher level nodes is piggy-backed to registration packets transmitted by lower level nodes.

20. The method according to claim 1, further comprising:

computing a network topology.

21. The method of claim 20, wherein the network topology is computed to reduce power consumption.

22. The method of claim 20, wherein the network topology is computed so that an expected battery life of all nodes is essentially equalized.

23. The method of claim 1, further comprising:

distributing a network topology.

24. The method of claim 23, wherein the step of distributing the network topology further includes:

transmitting topology a plurality of topology establishment packets.

25. The method of claim 24, wherein the topology establishment packets are transmitted in a random manner.

26. The method of claim 24, wherein the topology establishment packets are transmitted in level-wise time-slotted manner.

27. The method of claim 26, wherein a transmission period is divided into a time slot for each level of the sensor node network.

28. The method of claim 1, wherein the at least one link of the sensor node network is assessed to update at least one statistic of the at least one link.

29. The method of claim 1, wherein the at least one link of the sensor node network is assessed based on at least one of a power level and a packet success rate to reachable network elements.

30. A method to wirelessly network a sensor node, comprising:

installing the sensor node in a sensor node network arranged in a hierarchical manner with a plurality of node levels and a cluster head network;

assigning a unique identifier to the sensor node;

initializing the sensor node network, wherein the initializing includes;

establishing a temporary topology and synchronizing the sensor node network;

discovering and assessing at least one link of the sensor node network; and

registering a sensor node of the sensor node network with a cluster head of the cluster head network;

waking-up the sensor node to perform a task; and

setting the sensor node to an active low power mode prior to a propagation of messaging to all node levels in the sensor node network if the task is complete.

31. The method of claim 30, further comprising:

distributing an encryption key to the sensor node.

32. The method of claim 30, further comprising:

supervising the sensor node network with acknowledged supervision packets to update a clock of the sensor node.

33. The method of claim 32, wherein the supervision packets are sent in a periodic manner.

34. The method of claim 30, wherein a clock of the sensor node is synchronized with respect to its node level.

35. The method of claim 30, further comprising:

assigning the sensor node to a single one of the plurality of node levels, wherein each of the nodes of the sensor node network is assigned to a single respective one of the plurality of node levels.

36. The method of claim 35, wherein the assignment of the nodes to the respective node levels is in accordance with respective power constraints of the nodes.

37. The method of claim 30, wherein each of the nodes of the sensor node network is assigned to a respective one of the plurality of node levels and each of the plurality of node levels is assigned a respective one of a plurality of communication time slots.

38. A method to wirelessly network a sensor node, comprising:

installing the sensor node in a sensor node network arranged in a hierarchical manner with a plurality of node levels and a cluster head network;

assigning a unique identifier to the sensor node;

initializing the sensor node network, wherein the initializing includes;

establishing a temporary topology and synchronizing the sensor node network;

discovering and assessing at least one link of the sensor node network; and

registering a sensor node of the sensor node network with a cluster head of the cluster head network; and

the sensor node;

periodically entering an awake state;

activating a receiver component, the receiver component performing a receiver-signal strength measurement in a reserved channel;

determining if the strength measurement is greater than a threshold;

responsive to the determination of the strength measurement;

when the strength measurement is not greater than the threshold, entering an active low power mode; and

when the strength measurement is greater than the threshold, determining whether a wakeup sequence is included at a start of a message that has been received; and

responsive to the determination of the wakeup sequence;

when the wakeup sequence is included, maintaining the awake state to perform a task for performance of which the wakeup sequence was transmitted, the task including determining intended recipients of the message, and subsequently entering the active low power mode, prior to a propagation of the message to all node levels in the sensor node network, once the task is complete; and

when the wakeup sequence is not included, entering the active low power mode.