Protocol for reliable, self-organizing, low-power wireless network for security and building automation systems

• US 20030152041A1
• Filed: 11/21/2002
• Published: 08/14/2003
• Est. Priority Date: 01/10/2002
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Herrmann, Falk, Hill, Jason, Manjeshwar, Arati
• Granted Patent: US 7,483,403 B2
• Time in Patent Office: Days
• US Class Current: 370/310
• 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 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;

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

setting the sensor node to an active low power mode after one of initialization and performing the task.

2. The method of claim 1, further comprising:

distributing an encryption key to the sensor node.

3. 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.

4. The method according to claim 3, 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.

5. The method of claim 4, wherein the lower level node is the cluster head and the high level node is a first level sensor node.

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

7. The method of claim 4, wherein the higher level node is an upper limit level node.

8. The method of claim 3, wherein the step of discovering and assessing further includes:

broadcasting a plurality of link assessment packets.

9. The method of claim 8, wherein the link assessment packets are broadcast in a fully randomized manner.

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

11. The method of claim 10, wherein a broadcast period is divided into a time slot for each level of the sensor node network.

12. The method of claim 11, wherein the broadcast occurs only within a small fraction of the time slot.

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

14. The method of claim 11, wherein the broadcast occurs based on a unique identifier associated with the sensor node.

15. The method of claim 11, wherein the broadcast occurs based on a code to ensure that any two node interfere at most in only one time slot.

16. The method of claim 3, wherein the step of registration further includes:

forwarding a plurality of registration packets.

17. The method of claim 16, wherein the registration packets are forwarded in randomized individual node approach.

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

19. The method of claim 18, wherein a broadcast period is divided into a time slot for each level of the sensor node network.

20. The method of claim 19, wherein a broadcast order for the each level includes a higher to lower order.

21. The method of claim 16, wherein registration data from higher level nodes is piggy-backed to registration packets transmitted by lower level nodes.

22. The method according to claim 3, further comprising:

computing a network topology.

23. The method of claim 22, wherein the network topology is computed to reduce power consumption.

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

25. The method of claim 3, further comprising:

distributing a network topology.

26. The method of claim 25, wherein the step of distributing the network topology further includes:

transmitting topology a plurality of topology establishment packets.

27. The method of claim 26, wherein the topology establishment packets are transmitted in a random manner.

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

29. The method of claim 28, wherein a transmission period is divided into a time slot for each level of the sensor node network.

30. A method for monitoring an RF channel of a transmission link for a sensor node of a sensor node network, comprising:

performing a RSSI reading;

searching a preamble for a characteristic RF wakeup sequence;

searching for a valid start sequence;

reading a packet header of an incoming packet;

performing a task according to contents of the incoming packet; and

setting the sensor node to an active low power mode;

wherein the characteristic RF wakeup sequence is segregated among multiple RF channels according to tasks to be performed by the sensor node, the tasks being assigned relative priorities so that the tasks are monitored at different frequencies according to a respective required latency.

31. The method of claim 30, wherein the step of searching for a valid start sequence further includes:

scanning for the valid start sequence according to the assigned relative priorities.

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

waking-up a sensor node;

transmitting a message; and

setting the sensor node to an active low power mode.

33. The method of claim 32, wherein the sensor node is woken-up one to four times per second.

34. The method of claim 32, wherein the step of transmitting the message further includes:

transmitting a plurality of high-priority control packets.

35. The method of claim 34, wherein the high-priority control packets are transmitted in multicast to nodes in several of the node levels.

36. The method of claim 34, wherein the high-priority control packets are transmitted in unicast to a single node.

37. The method of claim 34, further comprising:

piggy-backing a low-priority message onto a supervision acknowledgement packet.

38. The method of claim 32, wherein the step of transmitting the message further includes:

transmitting a plurality of alarm packets.

39. The method of claim 38, wherein the alarm packets are transmitted via a directed flooding approach.

40. The method of claim 39, further comprising:

broadcasting a wakeup sequence prior to transmitting the alarm packets; and

forwarding the wakeup sequence and alarm packets to the cluster head network via an intermediate sensor node.

41. The method of claim 32, wherein the step of transmitting the message further includes:

transmitting an alarm packet in unicast via a separately-defined topology.

42. The method of claim 32, wherein the step of transmitting the message further includes:

transmitting a plurality of supervision packets via one of a level-based time slot approach, a parent-children level-based time slot approach, and a parent-child level-based time slot approach.

43. The method of claim 42, wherein the supervision packets are sent once per hour.

44. The method claim 32, wherein the step of transmitting the message further includes:

transmitting a plurality of link assessment packets.

45. The method of claim 44, wherein the link assessment packets are transmitted in an RF channel separate from at least one of alarm packets and control packets.

46. The method of claim 44, wherein the link assessment packets are transmitted once per day.

47. The method of claim 32, wherein the step of transmitting the message further includes:

transmitting a SOS packet in response to a reset.

48. The method of claim 32, wherein the step of transmitting the message further includes:

transmitting a new node packet.

49. The method of claim 32, wherein the step of transmitting the message further includes:

transmitting a registration packet.