A method, node and system for detecting node disruption

Abstract

Systems and methods for detecting node outages in a mesh network are disclosed. A tracking node in the mesh network detects a set of signals originating from a tracked node in the mesh network. The set of signals includes beacons or communication messages sent by the tracked node. The tracking node determines that a threshold number of beacon intervals have elapsed since a most recent signal was received from the tracked node. The tracking node performs an outage verification based on data received from another node in the mesh network and updates a state of the tracked node. Based on the updated state, the tracking node outputs a probe to the tracked node, which requests a response to the probe. When no response to the probe is received from the tracked node, the tracking node sends an outage alert message to a next topology higher layer of the mesh network.

Description

[0001] This application is a divisional application of the invention patent application filed on May 29, 2020, with application number "202080056008.3" and invention title "A method, node and system for detecting node interruption". Technical Field

[0002] This disclosure generally relates to processes for detecting and reporting node outages (e.g., communication interruptions, building power outages, or grid power outages) and alarm events within a wireless network. Background Technology

[0003] Networked systems, such as smart electricity, gas, and water meters, and other smart devices (i.e., devices capable of connecting to and communicating with other devices or networks), can interconnect to facilitate inter-device communication. Furthermore, one or more smart devices within a networked system may be able to interconnect with the Internet or other networks. For example, a networked system provides a mechanism for smart devices to communicatively couple with each other and exchange data. A networked system may include one or more nodes that are directly or indirectly connected to a network (e.g., the Internet or an intranet) through additional layers such as parent nodes, root nodes, or hubs. A networked system may also include nodes linked to parent nodes or other child nodes to exchange data across the networked system.

[0004] Several issues have arisen regarding node reliability and node outage detection and reporting within a networked system. For example, a node may rely on a supercapacitor to provide sufficient power to send an outage indication after it stops receiving power from its primary power source. Over time, the liquid stored within the supercapacitor (e.g., an electrolyte mixture) may leak, potentially short-circuiting electrical components and causing premature node breakdown. Furthermore, outage indications sent by a supercapacitor-powered node may not always be detected by other nodes in the network due to the lossy nature of communication on a network. Consequently, an outage indication may never be received and reported to the headend system by other nodes in the network. Therefore, the detection and reporting of node outage events in the network to the headend system for further remedial action may be insufficient or inconsistent. Summary of the Invention

[0005] Aspects and examples of apparatus and processes for determining and reporting node outages and alarm events in a networked system of smart devices are disclosed. For example, a method for detecting node outages in a mesh network includes: during a first time period, detecting a set of signals originating from a second node in the mesh network tracked by a first node. The set of signals includes RF activity beacons or communication messages transmitted by the second node, and the RF activity beacons indicate the operational state of the second node. The set of signals is detected during a time period corresponding to at least a single activity beacon interval. The method further includes, during a second time period following the first time period, at the first node, determining the current state of the second node based on an activity beacon interval of a threshold number of past events since the most recent signal from the second node was detected. The most recent signal includes the most recent RF activity beacon or the most recent communication message. The method further includes receiving a high-level RF activity beacon from a third node indicating the operational state of the third node and including an identifier of the second node and the state of the second node; updating the current state of the second node at least in part based on the high-level RF activity beacon; and outputting a ping to the second node based on the current state of the second node, requesting a response to the ping. If no response to the probe is received from the second node within the response period, the method includes sending an interruption alert message to the next higher layer of the mesh network topology. The interruption alert message includes the identifier of the second node.

[0006] In another example, a node in the mesh network includes a processor configured to execute computer-readable instructions and a memory configured to store the computer-readable instructions, which, when executed by the processor, cause the processor to perform operations. The operations include: during a first time period, detecting a set of signals originating from a second node in the mesh network tracked by the node. This set of signals includes RF activity beacons or communication messages transmitted by the second node, and the RF activity beacons indicating the operational state of the second node. The set of signals is detected during a time period corresponding to at least a single activity beacon interval. The operations also include, during a second time period following the first time period, determining the current state of the second node based on a threshold number of activity beacon intervals since the most recent signal from the second node was detected, the most recent signal including the most recent RF activity beacon or the most recent communication message. The operations also include receiving a high-level RF activity beacon from a third node indicating the operational state of the third node and including the identifier of the second node and the state of the second node; and updating the current state of the second node at least in part based on the high-level RF activity beacon. The operations also include outputting a probe to the second node based on the current state of the second node, requesting a response to the probe. If no response to the probe is received from the second node within the response period, the operation includes sending an interruption alert message to the next higher layer of the mesh network topology, the interruption alert message including the identifier of the second node.

[0007] In another example, a system includes multiple nodes communicatively connected via a mesh network, the multiple nodes including a first node, a second node, and a third node. The second node is configured to transmit signals including communication messages and RF activity beacons, the RF activity beacons indicating the operational state of the second node. The first node is configured to track the state of the second node. The tracking includes detecting a set of signals originating from the second node during a first time period. This set of signals is detected over a time period corresponding to at least a single activity beacon interval. The tracking also includes determining the current state of the second node during a second time period following the first time period, based on an activity beacon interval of a threshold number of past events since the most recent signal from the second node was detected. The most recent signal includes the most recent RF activity beacon or the most recent communication message. The tracking also includes receiving advanced RF activity beacons from the third node, the advanced RF activity beacons indicating the operational state of the third node and including an identifier of the second node and the state of the second node, and updating the current state of the second node based on the advanced RF activity beacons. The tracking also includes outputting a probe to the second node based on its current state, requesting a response to the probe; and sending an interruption alert message to the next higher layer of the mesh network topology when no response to the probe is received from the second node within the response period. The interruption alert message includes the identifier of the second node.

[0008] The illustrative aspects and features mentioned are not intended to limit or restrict the subject matter described herein, but rather to provide examples to aid in understanding the concepts described in this application. Other aspects, advantages, and features of the subject matter will become apparent after reading the entire application. Attached Figure Description

[0009] These and other features, aspects and advantages of this disclosure will be better understood when the following detailed description is read in conjunction with the accompanying drawings.

[0010] Figure 1 This is a block diagram illustrating an example of a networked system for smart devices based on one or more examples.

[0011] Figure 2 This is a diagram of an example protocol stack for a single radio transceiver device that implements multiple media access control protocols.

[0012] Figure 3 This is a diagram illustrating an example of a time slot in a Time Slot Channel Frequency Hopping (TSCH) network.

[0013] Figure 4 It is a state transition diagram that shows the various states determined for the tracked node based on one or more examples.

[0014] Figure 5 The following examples are shown for detection. Figure 1 An example of the process of a node interruption in a networked system.

[0015] Figure 6 The following examples are shown for verification. Figure 1 An example of the process of tracking the state of a node in a networked system.

[0016] Figure 7 The following examples are shown for verification. Figure 1 Another example of the process of tracking the state of a node in a networked system.

[0017] Figure 8 The following is illustrated based on one or more examples. Figure 1 An example of a block diagram of nodes in a networked system. Detailed Implementation

[0018] Systems and methods are provided for determining node outages and alarm events in a networked system for smart devices. As used herein, a node outage can include a communication interruption of the node, a building power outage at the node's location, or a power grid outage at the node's location. Within a networked system, a node can be any point in the networked system capable of sending and receiving data to or from other nodes or a centralized network (e.g., the Internet or an intranet). To provide proper accounting of the state of nodes connected to the networked system, the networked system includes a process for managing node outage detection at nodes connected to the networked system using node capabilities.

[0019] In operation, nodes in a networked system can be configured to output beacon signals, such as radio frequency (RF) signals, indicating that the node is operational; these are referred to herein as "RF active beacons" or "RF active beacon signals." RF active beacon signals provide a preamble that identifies the RF active beacon signal as a beacon signal, as well as an identifier of the node from which the RF active beacon signal originated. Nodes can be configured to send RF active beacon signals, such as data messages or network communication messages, when no other signals are available to transmit. Other nodes in the network that can receive RF active beacon signals from a node (the tracked node) can track the node's status based on the RF active beacon signals and other signals transmitted by that node.

[0020] If a tracking node does not receive a signal from the tracked node within a specified number of active beacon intervals, the tracking node can determine that the tracked node is in a suspected outage state. To confirm that the tracked node is indeed experiencing an outage, the tracking node can probe the tracked node, requesting a response from the tracked node indicating that the tracked node is still operating. If no response is received from the tracked node, the tracking node can send an outage alert message through the network system layer.

[0021] Each layer of the network system can process, filter, and merge outage alarm messages, allowing the root node to receive indications of all malfunctioning nodes in the network system, with minimal or no repeating indications of node outages. A root node connected to the headend system via a centralized network (e.g., the Internet) can provide the headend system with indications of malfunctioning nodes as alarm packets. At the headend system, actions can be taken to address malfunctioning nodes. For example, technicians can be deployed to perform physical checks and repairs on malfunctioning nodes. In another example, where nodes are associated with endpoints of the power grid, multiple malfunctioning nodes can indicate power outages. Information about malfunctioning nodes can be used to provide customers with accurate outage information or to identify the scope of the problem.

[0022] To reduce the likelihood of false positive outage detections, tracking nodes can perform outage verification, for example, before or after sending a probe to the tracked node. Outage verification can be performed by configuring nodes in the network to include the status of their respective tracked nodes in RF activity beacons (also known as Advanced RF Activity Beacon signals) emitted by individual nodes. In other words, an Advanced RF Activity Beacon signal is a beacon indicating the operational status of the node sending the RF activity beacon and includes the status information of the tracked node. Therefore, tracking nodes can update the status of tracked nodes based on Advanced RF Activity Beacon signals emitted by other nodes that are also tracking the tracked node. Outage verification can also be performed by the tracking node requesting status information from other tracking nodes of the tracked node. If the outage verification shows that the tracked node is still operational, the tracking node can avoid sending probe and / or outage alert messages. This reduces the likelihood of false positive outage detections and network traffic.

[0023] To further improve network efficiency, nodes can be configured to support two Media Access Control (MAC) protocols and can switch between listening for data or network management communications on one network and listening for RF active beacon signals on another network (RF beacon network). This allows nodes to perform RF active beacon signal detection when they are not receiving data or network management communications, thereby improving communication efficiency and reducing interruptions to normal data or network management communications.

[0024] Figure 1This is a block diagram illustrating an example of a networking system 100 and a mesh network 101. The networking system 100 and mesh network 101 provide network infrastructure for smart devices (e.g., resource consumption meters, vehicles, home appliances, etc., including those with communication technologies) to communicate across networks, the Internet, and / or intranets of nodes (i.e., other smart devices). The networking system 100 includes a headend system 102, which can be used as a central processing system to receive data streams from a network 104. The network 104 can be the Internet, an intranet, or any other data communication network. The mesh network 101 can include a root node 106 and other nodes 108a-108h that collect data associated with nodes 106 and 108a-108h, and the root node 106 sends the collected data to the network 104 and ultimately to the headend 102 of the networking system 100. Additionally, the root node 106 can also receive network management messages from the headend 102 and send these messages to nodes 108a-108h. Similarly, root node 106 itself or other nodes 108a-108h can also publish and send network management messages to other nodes 108a-108h. The data and network management messages sent between nodes 106 and 108a-108h are collectively referred to here as "communication messages". These communication messages are sent and routed via data link 110 between nodes 106 and 108a-108h. Root node 106 can be a Personal Area Network (PAN) coordinator, an Internet gateway, or any other device capable of connecting to network 104.

[0025] Root node 106 is often referred to as a parent node due to data links with nodes 108a and 108b in the node layer below root node 106 (e.g., layer one). For example, root node 106 is shown communicating directly with network 104. As shown, nodes 108a and 108b can also be referred to as parent nodes due to data links with nodes 108c, 108d, 108e, and 108g in the node layer below nodes 108a and 108b (e.g., layer two). Additionally, nodes 108e and 108g can be referred to as parent nodes due to data links with nodes 108f and 108h in the node layer below nodes 108e and 108g (e.g., layer three). Nodes 108a-108h can funnel all information upwards through the node layers to root node 106 and ultimately to headend 102.

[0026] Each of nodes 106 and 108a-108h is linked to at least one of the other nodes 106 and 108a-108h. Link 110 can be created by storing neighbor information in a neighbor cache of nodes 106 and 108a-108h, which provides nodes 106 and 108a-108h with indications of other nodes 106 and 108a-108h through which data can be routed. For example, the neighbor cache of node 108h may include neighbor information identifying that data collected at node 108h should be sent to node 108g. Similarly, the neighbor cache of node 108g may include neighbor information identifying that node 108g should send relevant information (e.g., network management messages or other information from headend 102) to node 108h, and also identifying that node 108g should send data collected by node 108g and data received from node 108h to node 108b. This data transmission scheme can continue upwards through the node layer of mesh network 101.

[0027] In operation, fewer or more nodes 108 can be included in the mesh network 101, and more root nodes 106 can also be included in the networking system 100. Additionally, although... Figure 1 The mesh network 101 depicted includes a root node layer (i.e., root node 106), layer one (i.e., nodes 108a and 108b), and layer two (i.e., nodes 108c, 108d, 108e, and 108g), but fewer or more node layers are also envisioned. Furthermore, although... Figure 1 It describes a specific network topology (e.g., DODAG tree topology), but other network topologies are also possible (e.g., ring topology, mesh topology, star topology, etc.).

[0028] The headend system 102 can track operational and non-operational nodes 106 and 108a-108h. To track the status of nodes 106 and 108a-108h, nodes 106 and 108a-108h transmit radio frequency (RF) beacon signals of sufficient strength to be received only by other nodes 106 and 108a-108h that are physically close to the transmitting nodes 106 and 108a-108h. These active RF beacon signals can be used to indicate that the transmitting nodes 106 and 108a-108h are operational (i.e., have not experienced a power outage).

[0029] For example, node 108h can transmit an RF active beacon signal with a strength only sufficient for nodes 108e, 108f, and 108g to continuously receive the RF active beacon signal. In one example, the RF active beacon signal can be referred to as a limited-range beacon because the transmission strength of the RF active beacon signal may be limited. The RF active beacon signal is restricted to be received by other nodes 106 and 108a-108h located within the transmission strength radius of the node transmitting the limited-range beacon. In this way, the RF active beacon provides peer-to-peer communication between a subset of nodes 106 and 108a-108h located within the transmission strength radius of the node transmitting the limited-range beacon.

[0030] The RF active beacon signal may include an identifier of the node 106 or 108a-108h that transmitted the RF active beacon signal. For example, the RF active beacon signal may include a preamble identifying the RF active beacon signal as a beacon signal, as well as an identifier of the node 106 or 108a-108h from which the RF active beacon signal originates. A representation consisting only of a preamble and node identifier may be only 4-8 bytes of data, but larger or smaller RF active beacon signals are also anticipated. Other information associated with the transmitting node 106 or 108a-108h is also expected to be included as part of the RF active beacon signal.

[0031] In one example, the strength of the RF active beacon signal output by each of nodes 106 and 108a-108h can be adjusted such that between 5 and 10 other nodes 106 and 108a-108h receive the RF active beacon signal from that single node. In such an example, the strength of the RF active beacon signal can be 0 dBm or in the range of -3 dBm to 10 dBm, and the strength can be adjusted based on how many of the nodes 106 and 108a-108h are located close to the node 106 or 108a-108h transmitting the RF active beacon signal. That is, depending on the specific arrangement of the additional nodes 106 and 108a-108h in the mesh network 101, the strength of the RF active beacon signal can be increased to reach the additional nodes 106 and 108a-108h, or decreased to reach fewer additional nodes 106 and 108a-108h. In one example, when the strength of the RF active beacon signal is such that six nodes receive the RF active beacon signal with a success rate greater than 50%, the subsequent success rate of each RF active beacon signal reaching at least one of the six nodes will be at least 98.4% (i.e., 1-0.56). This success rate can be increased based on an increase in the number of nodes 106 and 108a-108h within the range of transmitting nodes 106 or 108a-108h, an increase in the success rate of individual receiving nodes 106 and 108a-108h, or both.

[0032] RF active beacon signals can be transmitted by each of nodes 108a-108h at defined active beacon intervals. For example, nodes 108a-108h can transmit an RF active beacon signal every 5 seconds. Longer or shorter active beacon intervals can also be considered. Furthermore, each of nodes 108a-108h can control its own active beacon interval, and synchronization of active beacon intervals can be performed without crossing nodes 108a-108h. In one example, the time intervals between RF active beacon signals can be selected to achieve an optimal balance between one or more of the following factors: 1) increasing the uniformity of RF active beacon signals from transmitting nodes, 2) minimizing interference from other RF active beacon signals or other RF transmissions from the mesh network, and 3) maximizing the resolution of interruption event timestamps. For example, maximizing the resolution of interruption event timestamps might require reducing the active beacon interval to a smaller time interval, while minimizing interference from other RF sources might require increasing the active beacon interval to a larger time interval.

[0033] In some examples, tracking nodes 106 or 108a-108h can implement two MAC protocols using a single transceiver device (e.g., a single radio), allowing data and network management communications to be performed using one MAC protocol, and RF active beacon communications to be performed using another MAC protocol. See below for reference. Figure 2 and 3 Additional details are provided regarding the implementation based on the two MAC protocols.

[0034] Over time, each of nodes 106 and 108a-108h receives RF active beacon signals from one or more other nodes 106 and 108a-108h. When receiving nodes 106 and 108a-108h receive RF active beacon signals from one or more other nodes 106 and 108a-108h at an active beacon interval percentage greater than a threshold percentage, receiving nodes 106 and 108a-108h can track when RF active beacon signals from one or more other nodes 106 and 108a-108h are lost. For example, the threshold percentage can be set to p%. If receiving node 106 or 108a-108h receives RF active beacon signals from another node 106 or 108a-108h during M active beacon intervals out of a total of N active beacon intervals, and M / N > p%, then the receiving node (also called the "tracking node") can track the state of the sending node (also called the "tracked node"). In the following description, node 108h is used as an example of a tracked node, and node 108f is used as an example of a tracking node that tracks the state of tracked node 108h. It should be understood that any node 106 or 108a-108h in the mesh network can be either a tracked node or a tracking node. Furthermore, node 106 or 108a-108h can be a tracked node that is tracked by other nodes, and simultaneously a tracking node that tracks the state of other nodes.

[0035] Tracking involves determining the number of active beacon intervals for which no RF active beacon signals were received during the tracking period. After losing RF active beacon signals for a predetermined number of active beacon intervals from the tracked node 108h, the tracking node 108f can determine that the tracked node 108h is in a suspected outage state and can initiate a node probing process to actively request a response from the tracked node 108h. In some examples, the tracking node 108f performs outage verification before initiating the node probing process. For example, the tracking node 108f can perform outage verification based on information contained in advanced RF active beacons received from other tracking nodes. In this example, the advanced RF active beacon signals sent by the tracked nodes 106 or 108a-108h can be configured to include additional information, such as the status of other nodes 106 and 108a-108h. Since the tracked node 106 or 108a-108h can also be a tracking node tracking the state of other nodes 108a-108h, the tracked node 106 or 108a-108h knows the state of its tracked nodes 106 and 108a-108h, and such state information can be included in the Advanced RF Activity Beacon signal sent by the tracked node 106 or 108a-108h. As a result, any node that receives the Advanced RF Activity Beacon signal sent by the tracked node 106 or 108a-108h can obtain the state of those nodes.

[0036] Continuing the example above, tracking node 108f can perform interruption verification based on advanced RF activity beacons received from one or more other nodes 106 and 108a-108h (such as node 108e) that are also tracking the tracked node 108h. Tracking node 108f can compare its own determined state of the tracked node 108h with the state of the tracked node 108h indicated in the advanced RF activity beacons received from other nodes to determine whether the tracked node 108h is indeed in an interrupted state. For example, tracking node 108f may determine that the tracked node 108h is in a suspected interrupted state after failing to receive an RF activity beacon from the tracked node 108h for a predetermined number of activity beacon intervals. However, if the advanced RF activity beacons received from other nodes indicate that the state of the tracked node 108h is operational, tracking node 108f can update the state of the tracked node 108h to "operable" without initiating a node probing process. In this way, false positive interruption indications can be reduced, and communication can be reduced (e.g., eliminating communication involved in node probing).

[0037] The interruption verification process can also be performed by the tracking node 108f, which requests the status of the tracked node 108h from other nodes (e.g., its neighboring nodes). The responses received from those nodes can be used to confirm that the tracked node 108h is in a suspected interruption state. See below for reference. Figure 6 and 7 Additional details regarding interruption verification are provided. If the tracking node 108f confirms that the tracked node 108h is in a suspected interruption state, the tracking node 108f can initiate a node probing process.

[0038] In one example, the node probing process may involve the tracking node 108f sending a probe (e.g., a request for a response) to the tracked node 108h. The node probing process provides an additional detection layer to ensure that the tracked node 108h is not functioning correctly before sending an interruption alarm message. The probe can be sent at the full power strength of the tracking node 108f (e.g., 20dBm–30dBm). If the tracked node 108h is still operational, it can send a message back to the tracking node 108f at full power strength, indicating its operational status. In such an example, the beacon process can resume without escalating the interruption alarm message to other node layers of the mesh network 101.

[0039] If the tracked node 108h ceases operation, such as due to a continuous power loss without an alternative power source, no response to the probe will be received at the tracking node 108f. To reduce the likelihood that the tracking node 108f will fail to detect a response, the node probe process can be repeated two or more times. By repeating the node probe process, the possibility of false positive outage detections at the tracked node 108h can be significantly reduced.

[0040] When tracking node 108f does not receive a response from tracked node 108h during node probing, tracking node 108f can establish an interruption alarm message, which is directed to the node layer of mesh network 101. The interruption alarm message may include an identifier of the inactive tracked node 108h, as well as an indication of the timestamp of the most recent RF activity beacon signal (or other communication, if such other communication is also used to detect an interruption of the tracked node) received by tracking node 108f from tracked node 108h. In one example, tracking node 108f may combine the interruption alarm message from tracked node 108h with interruption alarm messages from other tracked nodes. Such encapsulation may be referred to as an alarm packet and is sent as a data message to the next higher-level node.

[0041] In some examples, if the tracking node 108f receives an RF activity beacon from the tracked node 108h after sending an alarm packet up through the hierarchical topology of the network, the tracking node 108f can mark the tracked node 108h as "recovered" or "operable" and continue tracking the status of the tracked node 108h as described above. In one example, when the tracked node 108h is marked as "recovered," the tracking node 108f can send a message indicating node recovery up through the hierarchical topology of the mesh network 101. The message indicating node recovery may include an identifier of the recovered node 108h.

[0042] When an alarm packet (e.g., a data packet including indications of multiple tracked nodes 106 and 108a-108h being in an outage state, as determined by one or more tracking nodes) is received at the next higher-level node 106 or 108a-108h, filtering and merging processes, such as at node 108e, may occur to prevent the transmission of unnecessary or duplicate outage indications. For example, the node 106 or 108a-108h receiving the alarm packet may resolve the alarm packet into multiple endpoint identifiers indicating which of nodes 106 and 108a-108h is indicated as being out of service in the alarm packet. Node 106 or 108a-108h analyzes the endpoint identifiers to obtain duplicate alarm indications (e.g., if node 106 or 108a-108h already knows that one or more of nodes 106 and 108a-108h are out of service). Non-duplicate alarm indications are stored for further analysis.

[0043] The stored alarm indications are then cross-referenced to see if any stored alarm indications originate from one of the nodes 106 or 108a-108h that monitors its RF activity beacon signal. If not, the analysis node 106 or 108a-108h forwards the alarm packet to the next higher node layer in the mesh network 101. If one or more stored alarm indications correspond to a node monitored by the analysis node 106 or 108a-108h, the analysis node 106 or 108a-108h determines whether it has received the RF activity beacon signal for one or more stored alarm indications to ensure that the RF activity beacon signal has not been missed by the nodes 106 or 108a-108h in the lower node layer of the mesh network 101 topology. If the analysis node 106 or 108a-108h has not received the RF activity beacon signal, the analysis node 106 or 108a-108h may forward the alarm packet to the next higher node layer in the mesh network 101 topology. If analysis nodes 106 or 108a-108h receive an RF active beacon signal, they can remove the node providing the RF active beacon signal from the alarm packet before sending an updated alarm packet to the next higher node layer in the mesh network 101. This process involves filtering out duplicate alarm indications from the alarm packet and also removing false positive interruption indications from the alarm packet before sending it to the next higher node layer in the mesh network 101.

[0044] When headend 102 receives an alarm packet from root node 106, headend 102 can deploy technicians to resolve one or more nodes 106 and 108a-108h that are identified as being out of service by the alarm packet. For example, technicians can be deployed to repair or replace nodes 106 and 108a-108h identified by the alarm packet. Furthermore, headend 102 can maintain records of the nodes 106 and 108a-108h that are out of service.

[0045] It should be understood that while the above description focuses on determining the state of a tracked node based on RF active beacon signals, other communications sent by the tracked node can also be utilized. For example, a tracking node can act as a "promiscuous node" and sniff or listen to any type of communication sent by the tracked node. When determining whether a tracked node is operational, the tracking node considers both the RF active beacon signals and other communications sent by the tracked node. These communications include data communications and network management communications. Because the transmit power of data or network management communications sent by the tracked node may be higher than that of the RF active beacon signals sent by the tracked node, the probability that the tracking node will receive data or network management communications may be higher than the probability that it will receive RF active beacon signals.

[0046] If a tracking node detects a communication message sent from a tracked node, it can determine that the tracked node is operational even if it has not received an RF active beacon from the tracked node for more than a predetermined number of active beacon intervals. In some examples, a missed interval counter can be used to track the number of consecutive active beacon intervals when no RF active beacon signal or communication message is received from the tracked node. Since a tracking node can track multiple tracked nodes, it can have a separate counter for each tracked node. When the tracking node detects data or network management communication or an RF active beacon signal from a tracked node, it can reset the missed interval counter for that tracked node. By taking both RF active beacon signals and other types of communication into account, the likelihood of the tracking node making false positive interruption determinations and generating unnecessary probes is reduced.

[0047] If the tracking nodes 106 and 108a-108h in the mesh network 101 are configured to detect the operational status of the tracked nodes based on both RF active beacons and communication messages, the tracked nodes can be configured to send RF active beacons only if they do not send any communication messages within a specific time period. This time period can correspond to one or more active beacon intervals.

[0048] In some cases, nodes 106 and 108a-108h support two or more Media Access Control (MAC) protocols, and nodes 106 and 108a-108h can be configured to use different MAC protocols to send RF active beacon signals and communication messages.

[0049] Figure 2 This is a diagram of an example protocol stack for a single radio transceiver device implementing multiple MAC protocols. Protocol stack 200 includes a physical interface (PHY) 210 at its bottom layer. PHY 210 can define the specifications of the physical transmission medium, such as the transceiver device of a node. The next layer after the node's protocol stack 200 includes at least two MAC layers 220a and 220b. For example, MAC layer 220a defines the addressing and channel access protocols for a first network (such as mesh network 101), allowing the transceiver device to communicate with other nodes by sending and receiving communication messages. Similarly, MAC layer 220b can define the addressing and channel access protocols for a second network, called an RF beacon network, allowing nodes to communicate with other nodes via RF active beacon signals. Traffic from both MAC layers 220a and 220b can be routed through a single IP layer 230. Signals from both networks can be transmitted via a transport layer (such as UDP 240). References will follow below. Figure 3 As described in detail, the two MAC layers can be the same protocol, but operate at different points in time (e.g., at two different parts of a time slot). Furthermore, in some examples, MAC layer 220b (e.g., the MAC layer for RF active beacons) may not proceed to the IP layer until it executes the beacon processing scheme described above.

[0050] Mesh network 101 can transmit data and network management messages within the network following the Slotted Channel Frequency Hopping (TSCH) communication protocol. Nodes within the network synchronize on the current TSCH time slot. To communicate with both the RF beacon network and mesh network 101 using a single transceiver, nodes 106 or 108a-108h can switch between mesh network 101 and the RF beacon network during TSCH time slots, resulting in interleaved communication with both mesh network 101 and the RF beacon network. Therefore, nodes 106 and 108a-108h can support both mesh network 101 (operating with the TSCH protocol) and the RF beacon network (which may or may not use the TSCH protocol) via transceiver devices.

[0051] Each time slot in the TSCH protocol has a duration of "T", which can be defined in milliseconds or other suitable time units. The TSCH protocol also uses multiple channel frequencies for communication between devices in the network. Frequency hopping patterns define the channels used for communication between nodes in the TSCH network during each time slot. For example, a frequency hopping pattern might determine that channel 4 is associated with time slot 1 and channel 6 is associated with time slot 2. Therefore, a node can determine, based on the frequency hopping pattern, that it should switch to channel 4 during time slot 1 and to channel 6 during time slot 2. A frequency hopping pattern can have a frequency hopping pattern length L, and the frequency hopping pattern repeats every L time slots.

[0052] Figure 3 A typical TSCH slot structure for slot 300 is shown. In this example, the time period shown is exemplary, and other values ​​can be used in other implementations (e.g., slot 300 is shown as having a duration of 25 milliseconds, but other slot durations are also possible). In the TSCH slot structure, nodes listen to the channel determined by the TSCH frequency hopping mode during the first part 308 of slot 300 for communication on the mesh network. Figure 3 As shown, after the RF settling period 302, a node can listen for signals on the channel for a period of time (displayed as receiver wait time 304). Typically, the duration of receiver wait time 304 depends on the expected transmit duration. The transmit duration can be defined in the IEEE 802.15.4e TSCH specification. If the node receives the start of a message before receiver wait time 304 expires, the node can proceed to receive the remainder of the message and process the received message. However, if the node does not receive the start of a message before receiver wait time 304 expires, the node can determine that it will not receive communication from another node on the mesh network during the current time slot. In a conventional network, the remainder of time slot 300 can be idle or unused.

[0053] In the current disclosure, after determining that a node will not receive communication in the first part of a time slot, the second part of the time slot that is in use can be used for RF active beacon communication. More specifically, nodes 106 or 108a-108h communicating on the mesh network 101 using the TSCH protocol can switch to an RF beacon network using another protocol during the unused portion of the TSCH time slot. Thus, as Figure 3As shown, in the second part of time slot 300, nodes 106 and 108a-108h can communicate in either the first network or the second network. If node 106 or 108a-108h receives the beginning of a message from another node 106 or 108a-108h on mesh network 101 during the first part 308 of time slot 300, node 106 or 108a-108h can continue receiving messages in the first network during the second part 310 of time slot 300 (e.g., for the duration of time slot 300). If node 106 or 108a-108h does not receive a message from mesh network 101 before the first part 308 of time slot 300 expires, node 106 or 108a-108h can switch to the beacon network and begin listening for RF active beacon signals from another node 106 or 108a-108h in the RF beacon network. If node 106 or 108a-108h operates in the second part of time slot 300 and receives a signal from the RF beacon network, then node 106 or 108a-108h can receive messages from the RF beacon network for the remaining duration of time slot 300. This reduces or eliminates idle time, and communication becomes more efficient.

[0054] Similarly, nodes 106 or 108a-108h can transmit data and network management messages on mesh network 101 and transmit RF active beacon signals on the RF beacon network. In some examples, the RF active beacon signals are transmitted at defined active beacon intervals, regardless of whether data and network management messages are transmitted within the active beacon interval. In other examples, particularly when the tracking node is configured to determine the operational status of the tracked node based on both the RF active beacon signals and data and network management messages, nodes 106 or 108a-108h can be configured to transmit RF active beacon signals on the RF beacon network only if no data or network management messages are transmitted on mesh network 101 during a given active beacon interval.

[0055] For example, during a time period when nodes 106 or 108a-108h have no data or network management messages to send on mesh network 101, the nodes can send RF active beacons for each active beacon interval. In the next time period when nodes 106 or 108a-108h have data or network management messages to send on mesh network 101, the nodes can send these data or network management messages as needed. The node can further determine whether it also needs to send RF active beacons. If at least one of the data or network messages was sent during the most recent active beacon interval, the node can skip sending the RF active beacon for that most recent active beacon interval; otherwise, the node will send the RF active beacon. In this way, the number of RF active beacon signals sent is reduced.

[0056] Alternatively, two different channels can be used for two networks. In other words, the mesh network 101 can operate on a first channel used for data and network management communications, and the RF beacon network can operate on a different channel used for RF active beacon signals. When using different channels, data and network management communications can use a channel frequency hopping sequence different from the channel frequency hopping sequence of the RF active beacon signals. For example, a tracking node can operate on a first frequency to detect communication messages on the mesh network. If no communication message is detected during the first part of a time slot of the TSCH protocol, the tracking node switches to the RF beacon network during the second part of the time slot by changing its frequency to a frequency different from the first frequency of the RF beacon network. This allows the RF active beacon signals to be transmitted at higher power because the RF active beacon signals interfere less with data and network management communications. In one example, the RF active beacon signals are transmitted using a power intensity substantially the same as that used to transmit communication messages. Sending a higher-power RF active beacon signal can increase the number of nodes 106 and 108a-108h that receive the RF active beacon signal, or increase the likelihood that nodes within the communication range of the RF active beacon signal will receive it. Therefore, false positive interruption detection can be reduced.

[0057] Figure 4 The diagram 400 illustrates the state transitions of various states of the tracked node, determined by the tracking node, based on one or more examples. (See diagram 400.) Figure 4 As shown, the tracked node can be identified as being in one of three possible states: operational state 402, suspected interruption state 404, and interruption state 406. If the tracking node can periodically detect signals (RF active beacon signals, data messages, or network management messages) sent from the tracked node, the tracked node is identified as being in operational state 402. (As mentioned above...) Figure 1 As discussed, if the tracking node does not detect a signal from the tracked node within a predetermined number of active beacon intervals, the tracking node can determine that the tracked node may be experiencing a power outage and is in a suspected outage state 404.

[0058] Tracking nodes can verify suspected outage states by performing outage verification to reduce false positive outage detections. Outage verification can be performed, for example, based on the tracked node's status information contained in high-level RF activity beacons sent by other nodes, or by actively requesting the tracked node's status. If outage verification fails—that is, the outage verification process shows the tracked node is still operational—the tracking node can mark the tracked node back to the operational state 402. This reduces the generation and transmission of unnecessary probes. If outage verification confirms the tracked node is inoperable (e.g., information from other nodes indicates the tracked node is in an outage state or a suspected outage state), the tracking node can further initiate a node probing process to actively seek a response from the tracked node.

[0059] If no response is received to the probe, the tracking node can determine that the tracked node is in an outage state 406. At this point, the tracking node can be configured to send an outage alert message to the next higher-level node. In some implementations, the tracking node can further perform outage verification before sending the outage alert message to ensure that the tracked node is indeed in an outage state 406, thereby further reducing the possibility of false positives in node outage detection. If the outage verification fails (i.e., the outage verification shows that the tracked node is operational), the tracking node can change the tracked node to an operational state 402. Furthermore, since promiscuous nodes are listening for network traffic, the tracking node can detect outage alert messages or alert packets sent by other nodes in the mesh network 101. If the tracking node detects an outage alert message or alert packet identifying the tracked node, the tracking node can avoid initiating an outage alert message for the tracked node or include the tracked node in the alert packets it creates. This provides the additional benefit of reducing network traffic.

[0060] If the tracking node detects a signal originating from the tracked node, such as an RF active beacon signal, data message, or network management message, while the tracked node is in a suspected outage state 404 or an outage state 406, the tracking node can change the tracked node's state back to the operational state 402. It should be understood that the various states and the conditions used for transitions between these states are for illustrative purposes only and should not be construed as limiting. Different conditions may trigger these state transitions. For example, if an outage verification shows that the tracked node is indeed experiencing an outage, the tracked node can transition from the suspected outage state 404 to the outage state 406 without sending a probe. See below for reference. Figure 5-7 Additional details are provided regarding determining the state of the tracked node.

[0061] Figure 5 It shows the detection Figure 1This is an example of an endpoint interruption process 500 in a networked system. One or more nodes (e.g., nodes 106 and 108a-108h) implement this by executing appropriate program code. Figure 5 The operation is illustrated. For illustrative purposes, process 500 is described with reference to certain examples depicted in the accompanying drawings. However, other implementations are also possible.

[0062] In box 502, process 500 involves tracking node 106 or 108a-108h listening for signals from the tracked node 106 or 108a-108h that the tracking node is tracking. As described above, in some examples, the tracking node can be configured to support two MAC protocols used in two networks: the TSCH protocol used by mesh network 101 and another protocol, such as the Wi-SUN CSMA-CA protocol, used by the RF beacon network. The tracking node can listen for data or network management messages in mesh network 101 during the first part of the TSCH time slot. If no communication messages are received during the first part of the time slot, the tracking node can switch to the RF beacon network to listen for RF active beacon signals.

[0063] In box 504, process 500 involves determining whether the tracking node received a signal from the tracked node during the current active beacon interval. In some examples, the tracking node determines whether an RF active beacon signal was received during the active beacon interval. In other examples, the tracking node is able to sniff or listen to any type of communication sent by the tracked node. In these examples, the tracking node may consider both the RF active beacon signal and the communication messages sent by the tracked node to determine whether the tracked node is operable. Thus, if the tracking node detects an RF active beacon signal or a data or network management message sent by the tracked node during the active beacon interval, the tracking node can determine that a signal was received from the tracked node.

[0064] If at least one signal is received from the tracked node, process 500 involves resetting the missed interval counter to zero in box 505, and then continuing to listen for signals from the tracked node in box 502. If no signal is received from the tracked node during the current active beacon interval, the tracking node increments the missed signal counter by one in box 506. In box 508, the tracking node determines whether the missed interval counter is higher than a threshold number of missed intervals. If not, the tracking node continues to listen for signals from the tracked node in box 502.

[0065] If the missed interval counter exceeds a threshold, the tracking node can determine that the tracked node is in a suspected outage state. In box 510, process 500 involves performing an outage verification to confirm that the tracked node is indeed inoperable and updating the state of the tracked node based on the outage verification. Outage verification can be performed based on additional information obtained from other nodes, such as the state of the tracked node contained in a high-level RF activity beacon signal sent by another node, or in response to a request for the state of the tracked node sent by the tracking node. See below for reference. Figure 6 and 7 Two examples of interrupted verification are described. The trace node can use... Figure 6 and 7 One or two of the interrupt verification methods shown are used to perform interrupt verification.

[0066] In box 512, process 500 involves determining whether the tracked node is identified as being in a suspected outage state. This determination may be based on the result of an outage verification. If the outage verification fails, meaning the tracked node remains operational, process 500 involves resetting the missed interval counter in box 505 and continuing to listen for signals from the tracked node in box 502. If the outage verification confirms the tracked node is in a suspected outage state, process 500 involves, in box 514, initiating a node probe process by sending a probe to the tracked node. The probe can be a signal requesting a response from the tracked node, and can be sent using the full power strength of the tracked node. In one example, the full power strength can be between 20 dBm and 30 dBm, but other signal strengths are also considered. The full power strength of the probe may be significantly greater than the strength of the RF active beacon signal to ensure the tracked node has a much better chance of receiving the probe.

[0067] In box 516, process 500 involves determining whether the tracking node received a probe response from the tracked node within a response period. The response period can be set from tens of milliseconds to several seconds. If the tracking node received a probe response, the missed interval counter is reset in box 505. When the missed interval counter is reset, the tracked node is marked as operational, and the tracking node continues to listen for signals from the tracked node. If the tracking node did not receive a probe response from the tracked node, process 500 may involve another interrupt verification at box 518, similar to the interrupt verification performed at box 510. If the interrupt verification confirms that the tracked node is indeed in an interrupted state, in box 522, the tracking node may send an interruption alert message indicating the interrupted state of the tracked node to the next higher-level node. If the interrupt verification shows that the tracked node is still operational, process 500 involves resetting the missed interval counter in box 505, and in box 502, the tracking node continues to listen for signals from the tracked node.

[0068] It should be understood that the above regarding Figure 5 The process 500 described is for illustrative purposes and should not be construed as limiting. The blocks of process 500 may differ from... Figure 5 The sequence shown is executed. Furthermore, process 500 may involve more or fewer blocks than those shown in Figure 500. For example, interrupt verification in box 510, interrupt verification in box 518, or both, can be omitted from process 500. In another example, an additional block can be added to process 500 before sending an interruption alert message to determine whether the interruption status of the tracked node has already been reported in an alert message sent by another node. If so, the tracked node can avoid sending an interruption alert message, thereby reducing network traffic.

[0069] As mentioned above, a node can be tracked by multiple tracking nodes. In this way, when determining the state of the tracked node, these multiple tracking nodes can cooperate with each other (e.g., exchange data). This can improve the accuracy of determining the state of the tracked node and reduce the false positive rate of detection. This process includes the steps outlined above. Figure 5 The interrupt verification process is described in boxes 510 and 518. Figure 6 and Figure 7 Examples of interrupting the verification process are shown in both examples.

[0070] In particular, Figure 6 An example of a process 600 for verifying the outage status of a tracked node based on advanced RF activity beacon signals sent by other tracking nodes of the tracked node is shown. In block 602, process 600 includes receiving an advanced RF activity beacon signal from another tracking node of the tracked node. In this example, nodes in mesh network 101 are configured to include additional information in the RF activity beacon signal (i.e., the advanced RF activity beacon signal). In addition to the identifier of the node sending the RF activity beacon signal, the advanced RF activity beacon signal may also include information about the node it is tracking. The information about the tracked node may include information identifying the tracked node and the status of each tracked node. In addition to the information identifying the tracked node and the status information, the advanced RF activity beacon signal may also include timestamps of recently received RF activity beacon signals or other communications received from each tracked node. This information may include all tracked nodes, or only those tracked nodes with a specific status, such as those nodes that the sending node has determined to be in a suspected outage state or an outage state. In some implementations, nodes 106 and 108a-108h in the mesh network 101 are configured to transmit advanced RF active beacon signals.

[0071] In box 604, process 600 involves parsing the advanced RF activity beacon signal to determine the state of the tracked node. In box 606, process 600 involves determining whether the advanced RF activity beacon signal indicates that the tracked node is operational. If so, process 600 involves updating the tracked node to operational in box 608. For example, the state of the tracked node can be updated by comparing the timestamp in the advanced RF activity beacon with the timestamp of the most recent signal received by the tracking node from the tracked node. If the timestamp in the advanced RF activity beacon is later than the timestamp of the most recent signal received by the tracking node from the tracked node, and it indicates that the tracked node transmitted a signal during the current time interval, then the tracked node can be determined to be in an operational state. In another example, if the advanced RF activity beacon indicates that the tracked node is operational, then the tracked node can be marked as being in an operational state.

[0072] If the advanced RF activity beacon signal indicates that the tracked node is inoperable, process 600 involves, in block 610, marking the tracked node as being in a suspected interrupted state or an interrupted state based on the state determined by the tracking node. For example, if the tracking node invokes interrupt verification when the state of the tracked node is determined to be suspected interrupted (e.g., after the tracking node fails to receive a signal from the tracked node within more than a threshold number of missed intervals and before probing the tracked node), and if the advanced RF activity beacon also indicates that the tracked node is in a suspected interrupted or interrupted state, the tracking node can determine that the tracked node is in a suspected interrupted state. In some implementations, if the advanced RF activity beacon indicates that the tracked node is in an interrupted state, the tracking node can determine that the tracked node is in an interrupted state, even if it determines that the tracked node is in a suspected interrupted state. This eliminates the need for endpoint probing.

[0073] Similarly, if a tracking node invokes interrupt verification when the state of the tracked node is determined to be interrupted (e.g., after the tracking node fails to receive a response to a probe), and if the advanced RF activity beacon indicates that the tracked node is in a suspected or interrupted state, the tracking node can determine that the tracked node is in an interrupted state. It should be further understood that the tracking node can further use additional information about the tracked node in the advanced RF activity beacon signal to determine how to prepare its own RF activity beacon signal, interruption alarm message, or alarm packet, such as avoiding generating and sending interruption alarm messages if other tracking nodes have already reported an interruption.

[0074] Figure 7An example of a process 700 for verifying the outage status of a tracked node by communicating with other tracking nodes of the tracked node is shown. In block 702, process 700 involves a tracking node sending a request to other tracking nodes of the tracked node to obtain information about the tracked node, thereby verifying its determination of an outage. In one implementation, the tracking node maintains information about other nodes tracking the same tracked node and sends requests to those nodes. Alternatively or additionally, the tracking node may send a request to its neighboring nodes. Neighboring nodes that are also tracking the same tracked node may respond to the request. Nodes may send requests using any of the methods described herein, such as via RF active beacon signals, data messages, network management messages, or any combination thereof. The request may be unicast or broadcast communication and, in some cases, sent at a reduced power level. The request may use the same network protocol used for other types of communication, or a local protocol may be used.

[0075] In box 704, process 700 involves receiving a response from the tracking node. The response contains information about the tracked node as determined by the corresponding tracking node. In box 706, process 700 involves determining whether the state of the tracked node in the response is consistent with the tracking node's interruption determination. If so, process 700 involves marking the tracked node as being in an interrupted state or a suspected interrupted state based on the state of the tracked node determined by the tracking node itself in box 708. If the state of the tracked node in the response is inconsistent with the tracking node's interruption determination, then in box 710, the tracking node may wait an additional amount of time before reporting an interruption (e.g., marking the tracked node as operational but assigning a non-zero value to a counter for missed intervals), or take further action, such as sending another probe to the tracked node (e.g., by marking the tracked node as being in a suspected interrupted state). By verifying the interruption of the tracked node in this way, global network traffic (e.g., interruption alert messages) can be reduced even if local traffic increases.

[0076] Exemplary node

[0077] Figure 8 This is an example of a block diagram of the components of a mesh network 101, specifically nodes 106 or 108. Some or all components of the computing system 800 may belong to... Figure 1 The nodes 106 or 108a-108h are one or more of the following. Node 800 includes a communication module 816 and a metering module 818 connected via a local or serial connection 830. The communication module 816 is functional in sending and receiving various signals, such as RF active beacons (including advanced RF active beacons), data and network communication messages, interruption alarm messages, and other data, to and from other nodes in the mesh network 101 or RF beacon network.

[0078] Communication module 816 may include communication device 812, such as an antenna and a radio. Alternatively, communication device 812 may be any device that allows wireless or wired communication. Communication device 812 may include transceiver device, such as an RF transceiver, capable of sending and receiving RF communications from other nodes in mesh network 101. In some configurations, the transceiver device is capable of implementing at least two MAC interfaces to communicate with mesh network 101 and the RF beacon network, respectively, via two antennas or via a single antenna. Communication module 816 may also include processor 813 and memory 814. Processor 813 controls the functions performed by communication module 816, such as those described above. Figure 1-7 One or more operations are described. Memory 814 can be used to store data used by processor 813 to perform its functions.

[0079] The metering module 818 includes functions necessary for managing resources, particularly those required to allow access to and measurement of the resources used. The metering module 818 may include a processor 821, a memory 822, and measurement circuitry 823. Measurement circuitry 823 processes resource measurements and can be used as a sensor to collect sensor data. The processor 821 in the metering module 818 controls the functions performed by the metering module 818. The memory 822 stores data required by the processor 821 to perform its functions. Communication module 816 and metering module 818 communicate with each other via a local connection 830 to provide data required by other modules. Both communication module 816 and metering module 818 may include computer-executable instructions stored in memory or another type of computer-readable medium, and one or more processors within the module can execute the instructions to provide the functions described herein.

[0080] General considerations

[0081] This document sets forth numerous specific details to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will understand that the claimed subject matter can be practiced without these specific details. In other instances, methods, apparatus, or systems that should be understood by those skilled in the art have not been described in detail to avoid obscuring the claimed subject matter.

[0082] The features discussed herein are not limited to any particular hardware architecture or configuration. A computing device can include any suitable arrangement of components that provide a result conditioned on one or more inputs. Suitable computing devices include multi-purpose microprocessor-based computer systems that access stored software (i.e., computer-readable instructions stored in the memory of the computer system) that programs or configures the computing system from a general-purpose computing device to a special-purpose computing device that implements one or more aspects of this subject. Any suitable programming, scripting, or other type of language or combination of languages ​​can be used to implement the teachings contained herein in software for programming or configuring computing devices.

[0083] All aspects of the methods disclosed herein can be executed using such a computing device. The order of the boxes presented in the above examples can be varied; for example, the boxes can be reordered, combined, and / or decomposed into sub-boxes. Some boxes or procedures can be executed in parallel.

[0084] The use of “suitable for” or “configured to” here implies an open and inclusive language, which does not exclude devices suitable for or configured to perform additional tasks or steps. Furthermore, the use of “based on” implies an open and inclusive nature, meaning that a process, step, calculation, or other action “based on” one or more of the stated conditions or values ​​may also be based on additional conditions or values ​​beyond those stated. The headings, lists, and numbering included herein are for illustrative purposes only and are not restrictive.

[0085] Although the subject matter has been described in detail with respect to specific aspects, it should be understood that modifications, variations, and equivalents of these aspects will be readily apparent to those skilled in the art upon gaining an understanding of the foregoing. Therefore, it should be understood that this disclosure is presented for illustrative purposes rather than for limitation, and does not exclude such modifications, variations, and / or additions to the subject matter that would be readily apparent to those skilled in the art.

Claims

1. A method for detecting node interruption, comprising: During the first time period: A first node of the mesh network detects a set of signals originating from a second node of the mesh network tracked by the first node, wherein the set of signals includes RF active beacons or communication messages sent by the second node, the RF active beacons indicating the operational status of the second node, and wherein the set of signals is detected during a time period corresponding to at least a single active beacon interval; During the second time period following the first time period: At the first node, the current state of the second node is determined based on an active beacon interval of a threshold number of past events since the detection of the most recent signal from the second node, wherein the most recent signal includes the most recent RF active beacon or the most recent communication message. At the first node, an advanced RF activity beacon is received from the third node, the advanced RF activity beacon indicating the operational status of the third node and including the identifier and status of the second node; The first node updates the current state of the second node based at least in part on the advanced RF activity beacon; the update includes: The advanced RF activity beacon indicates that the second node is in an operational state; Update the current state of the second node to the operable state; and Reset the counter for the number of active beacon intervals that have elapsed since the second node received the most recent signal to zero; Output a probe to the second node based on the current state of the first node and the second node's request for a response to the probe; and If no response to the probe is received from the second node within the response period, the first node sends an interruption alert message to the next higher layer of the mesh network topology, the interruption alert message including the identifier of the second node.

2. The method of claim 1, wherein updating the current state of the second node based at least in part on the advanced RF activity beacon comprises: Based on the determination that the second node in the advanced RF active beacon is in a suspected interruption state or an interruption state, it is determined that the second node is in a suspected interruption state. In response to determining that the second node is in a suspected interrupt state, an output probe is executed.

3. The method of claim 1, wherein the advanced RF activity beacon further includes a timestamp of the most recent signal received by the third node from the second node, and wherein updating the current state of the second node based at least in part on the advanced RF activity beacon comprises: Based on determining that a threshold number of active beacon intervals have elapsed since the timestamp of the most recent signal detected by the first node from the second node or the most recent signal received by the third node from the second node, it is determined that the second node is in a suspected outage state. In response to determining that the second node is in a suspected interrupt state, an output probe is executed.

4. The method according to claim 1, further comprising: The first node sends an RF activity beacon, which is a high-level RF activity beacon indicating the operational status of the first node and including an indication of the current status of the second node.

5. The method according to claim 1, further comprising: Before sending the interruption alarm message, The first node sends a request for information about the second node to the fourth node; Receive a response to the request at the first node, including the status of the second node; The first node updates the state of the second node based on the response; and The interruption alarm message is sent based on the updated status of the second node.

6. The method of claim 5, wherein the request for the information is sent to a plurality of nodes including a fourth node, wherein the first node identifies the plurality of nodes as nodes that track the second node.

7. The method of claim 5, wherein the request for the information is sent to a plurality of nodes including a fourth node, wherein the first node identifies the plurality of nodes as neighboring nodes of the first node.

8. A node in a mesh network, comprising: The processor is configured to execute computer-readable instructions; The memory is configured to store computer-readable instructions that, when executed by the processor, cause the processor to perform operations including: During the first time period: The detection source is a set of signals from a second node of the mesh network tracked by the node, wherein the set of signals includes RF active beacons or communication messages sent by the second node, the RF active beacons indicating the operational status of the second node, and wherein the set of signals is detected during a time period corresponding to at least a single active beacon interval; During the second time period following the first time period: The current state of the second node is determined based on an active beacon interval of a threshold number of past events since the detection of the most recent signal from the second node, wherein the most recent signal includes the most recent RF active beacon or the most recent communication message. Receive advanced RF activity beacons from the third node, the advanced RF activity beacons indicating the operational status of the third node and including the identifier and status of the second node; The current state of the second node is updated at least in part based on the advanced RF active beacon; the update includes: The advanced RF activity beacon indicates that the second node is in an operational state; Update the current state of the second node to the operable state; and Reset the counter for the number of active beacon intervals that have elapsed since the second node received the most recent signal to zero; Based on the current state of the second node, output a probe to the second node, requesting a response to the probe; and If no response to the probe is received from the second node within the response period, an interruption alert message is sent to the next higher layer of the mesh network topology, the interruption alert message including the identifier of the second node.

9. The node of claim 8, wherein updating the current state of the second node based at least in part on the advanced RF activity beacon comprises: Based on the determination that the second node in the advanced RF active beacon is in a suspected interruption state or an interruption state, it is determined that the second node is in a suspected interruption state. In response to determining that the second node is in a suspected interrupt state, an output probe is executed.

10. The node of claim 8, wherein the operation further comprises: Before sending the interruption alarm message: Send a request for information about the second node to the fourth node; Receive a response to the request, including the status of the second node; Update the state of the second node based on the response; as well as The interruption alarm message is sent based on the updated status of the second node.

11. The node of claim 10, wherein the request for the information is sent to a plurality of nodes including a fourth node, wherein the nodes identify the plurality of nodes as nodes that track the second node.

12. The node of claim 10, wherein the request for the information is sent to a plurality of nodes including a fourth node, wherein the nodes identify the plurality of nodes as neighboring nodes of the node.

13. A system comprising a plurality of nodes communicatively connected via a mesh network, the plurality of nodes including a first node, a second node, and a third node, wherein: The second node is configured to send signals including communication messages and RF activity beacons, the RF activity beacons indicating the operational status of the second node; as well as The first node is configured to track the state of the second node, the tracking including: During the first time period: A set of signals originating from the second node is detected, wherein the set of signals is detected during a time period corresponding to at least a single active beacon interval; During the second time period following the first time period: The current state of the second node is determined based on an active beacon interval of a threshold number of past events since the detection of the most recent signal from the second node, wherein the most recent signal includes the most recent RF active beacon or the most recent communication message. Receive advanced RF activity beacons from the third node, the advanced RF activity beacons indicating the operational status of the third node and including the identifier and status of the second node; The current state of the second node is updated based on the advanced RF active beacon; the update includes: The advanced RF activity beacon indicates that the second node is in an operational state; Update the current state of the second node to the operable state; and Reset the counter for the number of active beacon intervals that have elapsed since the second node received the most recent signal to zero; Based on the current state of the second node, output a probe to the second node, requesting a response to the probe; and If no response to the probe is received from the second node within the response period, an interruption alert message is sent to the next higher layer of the mesh network topology, the interruption alert message including the identifier of the second node.

14. The system of claim 13, wherein the plurality of nodes further comprises a fourth node, and the first node is further configured to: before sending the interruption alarm message: Send a request for information about the second node to the fourth node; Receive a response to the request, including the status of the second node; and The state of the second node is updated based on the response. The interruption alarm message is sent based on the updated status of the second node.

15. The system of claim 14, wherein the request for the information is sent to a group of nodes including a fourth node, wherein the first node identifies the group of nodes as a node that tracks the second node.

16. The system of claim 14, wherein the request for the information is sent to a group of nodes including a fourth node, wherein the first node identifies the group of nodes as neighboring nodes of the first node.

17. The system of claim 13, wherein updating the current state of the second node based at least in part on the advanced RF activity beacon comprises: Based on the determination that the second node in the advanced RF active beacon is in a suspected interruption state or an interruption state, it is determined that the second node is in a suspected interruption state. In response to determining that the second node is in a suspected interrupt state, an output probe is executed.

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