Mesh network and a method of operating the same

Abstract

There is provided a method of operating a mesh network (100). The method comprises: operating (S1) a node N2 of the mesh network in a first mode, wherein the node N2 operates as a full function device, FFD, in the first mode; and switching (S5) the node N2 from operating in the first mode to operating in a second mode, wherein the node N2 operates with a reduced routing functionality in the second mode as compared to the first mode.

Description

[0001] Mesh Network and a Method of Operating the Same

[0002] Technical Field

[0003] The present disclosure relates to a mesh network, a method of operating the same, and a node for use in a mesh network. More specifically but not exclusively, the present disclosure relates to a node which is transformable from operating as a full function device (FFD) in a first mode to operating with a reduced routing functionality in a second mode.

[0004] Background

[0005] In a mesh network (e.g., an RF mesh network), devices (e.g., Internet of Things, loT, devices) are capable of interconnecting with each other for inter-device communication, thereby collectively forming a mesh routing network to send data to a central coordinator. Generally speaking, the devices may have various functionalities while some of the devices may be designed to perform specific tasks. This distinction may be caused by the differences in the processing power, memory requirements and / or the power source (among other factors) amongst the devices. The devices may also be referred to as nodes of the mesh network. The mesh network plays an important role in Advanced Metering Infrastructure (AMI) systems and modern Smart Grid.

[0006] It is generally desirable to improve the robustness and the performance of the mesh network while reducing costs. It is an object of the present disclosure, among others, to provide such an improved mesh network.

[0007] Summary

[0008] According to a first aspect of the present disclosure, there is provided a method of operating a mesh network, comprising: operating a node of the mesh network in a first mode, wherein the node operates as a full function device, FFD, in the first mode; and switching the node from operating in the first mode to operating in a second mode, wherein the node operates with a reduced routing functionality in the second mode as compared to the first mode. Advantageously, the node can re-purpose (or reconfigure) itself to switch between operating in the first mode and operating in the second mode. An FFD is known to implement the full protocol set and has complete functionality (e.g., transmitting and receiving data, as well as routing data of itself and its child node(s) throughout the network to a central coordinator of the mesh network). By operating with a reduced routing functionality in the second mode, the node may direct some of its resources to performing specialised operations which may be memory / power intensive, or may direct some or all of its bandwidth to transmit high volume of traffic arising from a particular device (e.g., a sensor) connected to itself or included within itself. This avoids the needs of deploying a separate high-processing device to the mesh network, thereby saving the costs of the mesh network. Further or alternatively, by switching from the first mode to the second mode, the node may reduce its power consumption in the event of an interruption in power from an external power supply (e.g., mains power).

[0009] The mesh network may be referred to as an RF mesh network.

[0010] The node may operate as a reduced function device, RFD, in the second mode.

[0011] The node may not have any routing functionality in the second mode and may simply operate as an end node.

[0012] Operating the node in the first mode may comprises: receiving, by the node, data from at least one child node which is wirelessly linked to the node within the mesh network; and sending, by the node, the received data to a central coordinator of the mesh network; wherein one or more of the at least one child node is disconnected from the node when the node operates in the second mode.

[0013] In other words, the node operates as a full function router node in the first mode, and is linked with a lesser number of child node(s) in the second mode than in the first mode. In an embodiment, the node may not be linked with any child node and may operate as an end-point node in the second mode.

[0014] The method may further comprise: before switching the node from operating in the first mode to operating in the second mode, sending, by the node, a message to the at least one child node, wherein the message informs the at least one child node of the switching.

[0015] The method may further comprise: in response to receiving the message, connecting the one or more of the at least one child node to new parent node(s) within the mesh network.

[0016] The method may further comprise: determining, by the node, that the at least one child node comprises a critical node; wherein the critical node remains connected to the node when the node operates in the second mode.

[0017] In other words, the node will continue to route data from the critical node to the central coordinator when the node operates in the second mode.

[0018] Alternatively, switching the node from operating in the first mode to operating in the second mode may take place in response to determining that the at least one child node does not comprise any critical node.

[0019] The critical node may comprise one or more of the following:

[0020] a child node that is powered by battery only;

[0021] a child node which was previously switched from operating in the first mode to operating in the second mode; and

[0022] a child node which cannot find a new parent node within the mesh network.

[0023] The node may comprise a processor, and a memory storing a first firmware supporting the first mode and a second firmware supporting the second mode, and switching the node from operating in the first mode to operating in a second mode may comprise: switching the processor from executing the first firmware to executing the second firmware.

[0024] Alternatively, the memory of the node may store a single firmware, and switching the node from operating in the first mode to operating in a second mode may comprise: switching the processor from executing the single firmware with a first configuration to executing the second firmware with a second configuration which is different from the first configuration. Operating the node in the first mode may comprise running, by the node, a first application, and the first application is disabled by the node in the second mode or is run by the node at a lesser frequency in the second mode than in the first mode.

[0025] The first application may comprise low-priority application(s) such as sending periodic data to the headend system.

[0026] The method may further comprise: receiving, by the node, a mode-switching command from a headend system in communication with the mesh network, wherein the modeswitching command instructs the node to switch from operating in the first mode to operating in the second mode.

[0027] The method may further comprise: detecting an occurrence of an event while the nodes operates in the first mode; wherein the switching is performed if the occurrence of the event has been detected.

[0028] The detecting may be performed by the node or by the headend system.

[0029] The event may comprise one or more of the following:

[0030] a tamper event at the node;

[0031] a security breach at the node;

[0032] a volume or a rate of data traffic to be sent by the node exceeding a first threshold;

[0033] a power load of the node exceeding a second threshold; and

[0034] an interruption in power from an external power supply, wherein the node is operable to receive power from the external power supply in the first mode.

[0035] The mesh network may comprise a battery end point, BEP, node, which is a child node of the node in the first mode, and the method may further comprise: in response to switching the node from operating in the first mode to operating in the second mode, entering, by the BEP node, into a deep sleep mode.

[0036] The method may further comprise: switching the node from operating in the second mode to operating in the first mode, after a predetermined time period or receiving a command or an occurrence of an event. The command may be from the headend system. The event may comprise one or more of the following: a volume or a rate of data traffic to be sent by the node dropping below the first threshold; a power load of the node dropping below the second threshold; and a resumption in power from the external power supply.

[0037] The method may further comprise: receiving, by the node, a further mode-switching command from the headend system, wherein the further mode-switching command instructs the node to switch from operating in the second mode back to operating in the first mode.

[0038] The method may further comprise: after operating the node in the second mode for a predetermined period of time, switching the node from operating in the second mode back to operating in the first mode.

[0039] According to a second aspect of the present disclosure, there is provided a node for use in a mesh network, comprising: a communication module for communicating with at least one other node of the mesh network; and a controller configured to control the communication module; wherein the controller is configured such that the node is operable to switch its operation mode from a first mode to a second mode, wherein the node is configured to operate as an FFD in the first mode and to operate with a reduced routing functionality in the second mode as compared to the first mode.

[0040] The controller may comprise a processor and a memory storing a first firmware supporting the first mode and a second firmware supporting the second mode, and wherein the processor is configured to switch from executing the first firmware to executing the second firmware such that the node switches its operation mode from the first mode to the second mode.

[0041] Alternatively, the controller may comprise a processor and a memory storing a single firmware, and wherein the processor is configured to switch from executing the single firmware with a first configuration to executing the second firmware with a second configuration such that the node switches its operation mode from the first mode to the second mode, wherein the second configuration is different from the first configuration. As compared to the first configuration, the second configuration may disable a module within the single firmware, and / or may have different run time configuration parameters.

[0042] The node may be operable to receive power from an external power supply.

[0043] The node may comprise a backup battery for supplying power to the communication module and the controller.

[0044] The node may further comprise a metrology module arranged to measure consumption of a resource and to generate consumption data indicative of the consumption of the resource.

[0045] According to a third aspect of the present disclosure, there is provided a mesh network, comprising: a central coordinator; and a node according to the second aspect.

[0046] The mesh network may further comprise: at least one other node, wherein the node is configured to route data from the at least one other node to the central coordinator when the node operates in the first mode, and is configured to be disconnected from one or more of the at least one other node when the node operates in the second mode.

[0047] With the present disclosure, the “node” may be used interchangeably with “device”.

[0048] Where appropriate any of the optional features described above in relation to one of the aspects of the present disclosure may be applied to another one of the aspects of the disclosure.

[0049] Brief Description of the Drawings

[0050] In order that the disclosure may be more fully understood, a number of embodiments of the disclosure will now be described, by way of example, with reference to the accompanying drawings, in which:

[0051] Figure 1 is a schematic diagram showing an exemplary mesh network and its operating environment; Figures 2 and 3 are schematic diagrams showing new topologies of the mesh network after a node N2 has switched its operation mode;

[0052] Figure 4 is a schematic diagram showing an exemplary hardware architecture of the node N2 in the mesh network of Figures 1 to 3;

[0053] Figure 5 schematically illustrates processing steps of a method of operating a mesh network, according to an aspect of the present disclosure.

[0054] In the figures, like parts are denoted by like reference numerals.

[0055] It will be appreciated that the drawings are for illustration purposes only and are not drawn to scale.

[0056] Detailed Description of the Preferred Embodiments

[0057] Figure 1 schematically illustrates an exemplary mesh network 100 and its operating environment. The mesh network 100 includes multiple nodes N1 to N6 which are capable of communicating with each other so that data can be exchanged between the nodes N1 to N6. Figure 1 depicts a specific mesh topology in which the primary routes used by each node to transmit data are illustrated using double arrows (which indicate bidirectional communication between the associated notes). It would be understood that the mesh network 100 may contain any suitable number of nodes which may be interconnected in any suitable way. In the mesh topology of Figure 1, the nodes N3, N5 and N6 are end nodes or leaf nodes (i.e., without child node(s)). The node N2 is the parent node of the nodes N3 and N5, and routes data of itself and data from the nodes N3 and N5 to the node N1. The node N4 is the parent node of the node N6, and routes data of itself and data from the node N6 to the node N1. The node N1 is the parent node of the nodes N2 and N4, and routes data of itself and data from the nodes N2 to N6 to a central coordinator 10 of the mesh network. The central coordinator 10 may also be referred to as a gateway or a root node. Usually, the node (i.e., the node N1 in this example) having the best connectivity (e.g., the strongest signal) to the central coordinator 10 is directly connected to the central coordinator 10. The communications between the peer nodes N1 to N6 themselves and between any of the nodes N1 to N6 and the central coordinator 10 are wireless, and may be according to the IEEE 802.15.4 Standard although other wireless standards may be used. The central coordinator 10 communicates with a headend system (HES) 14 via a wireless network 12, although a wired connection via Ethernet LAN or fiber could also be used between the central coordinator 10 and the HES 14.

[0058] Generally speaking, the nodes N1 to N6 of the mesh network 100 may include measuring nodes for collecting data from the respective deployed locations of the nodes, processing nodes for processing data available to the nodes, router nodes for forwarding data received from one node to another node in the network 100, or nodes that are configured to perform a combination of these functions.

[0059] In an example, the mesh network 100 may be associated with a resource distribution network, such as a utility network, to deliver measurement data obtained in the resource distribution network. In this example, one or more of the nodes N1 to N6 may include or be connected to a utility meter (such as an electricity meter, a gas meter, a water meter or a steam meter) and / or any other type of loT devices, and be implemented to measure various operating characteristics of the resource distribution network, such as the characteristics of resource consumption. In a power distribution network (e.g., smart grid), one or more of the nodes N1 to N6 may monitor the grid and send alerts to the HES 14, and examples of the measured operating characteristics may include, but are not limited to, average or total power consumption, the peak voltage of the electrical signal, power surges, and load changes.

[0060] The HES 14 may function as a central processing system that receives streams of data or messages from the central coordinator 10. The HES 14 or another system associated with the HES 14 may process or analyse the collected data for various purposes, such as billing, performance analysis, or troubleshooting.

[0061] The following description relates to a particular example in which the node N2 is a reconfigurable node. The expression “reconfigurable” means that the functionality of the node N2 can be changed or modified after fabrication to serve different purposes. This is described below in more detail. Full function devices (FFD) and reduced function devices (RFD) are two known types of devices which take part in wireless personal area networks (WPAN). The two device types have different complexities. Generally speaking, an FFD implements the full protocol set of the WPAN and has the complete functionality. The FFD can perform tasks such as transmitting and receiving data, as well as routing communication throughout the mesh network. It has the ability to function as a network coordinator, a router node or an end node. On the other hand, an RFD is designed to have limited functionality, often serving as an end node only. Usually, an RFD lacks routing capabilities and can only communicate with an FFD. Within a WPAN, nodes which require only minimum functionality (such as switches and sensors) may be implemented as RFDs to reduce costs and power consumption of the mesh network. In known mesh networks, the device type of each node is fixed and cannot be changed or reconfigured after deployment of the networks.

[0062] The node N2 of the present disclosure, however, can transform or switch between operating as an FFD and operating as an RFD after deployment of the network 100 in response to network conditions. Figure 5 schematically illustrates processing steps performed by the node N2. The processing steps of Figure 5 are part of a method of operating the mesh network 100.

[0063] At step S1, the node N2 operates in a first mode (i.e., as an FFD). Being an FFD, the node N2 has full routing functionality, and routes data of itself and from its child nodes (e.g., N5 and N3) to the HES 14 via the central coordinator 10.

[0064] At step S2, the node N2 switches its operation mode from the first mode to a second mode. The node N2 operates with a reduced routing functionality (or capability) in the second mode as compared to the first mode. In an example (Figure 2), the node N2 operates as an RFD without any routing capability. In another example (Figure 3) where the child nodes of the node N2 include a critical node, the node N2 operates as an enhanced RFD with a very limited routing functionality.

[0065] An exemplary hardware architecture of the node N2 is illustrated in Figure 4. The node N2 comprises a communication module 20 and a controller 30 controlling the communication module 20. In an example where the node N2 also perform the function of a measuring node, the node N2 may comprise a metrology module 40 in communication with each of the communication module 20 and the controller 30. The communication module 20 is for transmitting / receiving data to / from other node(s) of the mesh network 100. The transmitted data includes the data from the node N2 itself (e.g., consumption data generated by the metrology module 40) and the data from the child nodes (e.g., N3 and N5) of the node N2. The communication module 20 typically includes a modulator, a front-end circuit and an antenna. The metrology module 40 performs core metrology functions of measuring consumption of one or more resources, such as water, thermal energy (e.g., heat, cooling or combined heat / cooling), electricity, or gas, and generating consumption data (among other types of data if any) indicative of the consumption of the resource. The metrology module 40 may include a metrology processor, which may be a microcontroller, for running metrology functions, and / or a memory for storing the consumption data. The controller 30 may comprise a processor and a memory which stores computer readable codes or instructions.

[0066] To effect the mode switching (or reconfiguration) of the node N2, the memory of the controller 30 may store a first firmware supporting the first mode and a second firmware supporting the second mode. By switching the processor of the controller 30 from executing the first firmware to executing the second firmware, the node N2 stops operating in the first mode and starts to operate in the second mode. The node N2 may be made with the memory of the controller 30 storing two sets of firmware as the factory setting. Alternatively, the memory of the controller 30 may be made with storing the first firmware only, and the node N2 may download the second firmware to its memory. The download of the second firmware may take place at any suitable time before step S2 (e.g., after step 01 of Figure 5).

[0067] Further alternatively, the memory of the controller 30 may store a single firmware only, which may be executed with different configurations. By switching the processor of the controller 30 from executing the firmware with a first configuration to executing the firmware with a second configuration, the node N2 stops operating in the first mode and starts to operate in the second mode. The second configuration may disable a module which is otherwise active under the first configuration, or may have different run time configuration parameters, thereby allowing the node N2 to switch modus operandi. The node N2 may perform one or more of optional steps 01 to 04 (Figure 5). Steps 01 to 03 may take place between steps S1 and S2. Step 04 may take place after step S2.

[0068] At step 01, the node N2 receives a mode-switching command from the HES 14 or detects an occurrence of particular event(s) (described below). The mode-switching command instructs the node N2 to switch from operating in the first mode to operating in the second mode. Alternatively, the node N2 may take a leading role in determining its operation mode by detecting the occurrence of the particular event(s). Upon detecting the occurrence of the particular event(s), the node N2 may automatically change its operation mode from the first mode to the second mode, or may seek an approval (i.e., awaiting the command) from the HES 14 before implementing the change.

[0069] The particular event(s) which trigger the mode switching of the node N2 may include: (i) a tamper event, (ii) a security breach, (iii) a surge of data traffic, (iv) a surge of power load, and (v) an interruption in power from an external power supply that is connected to the node N2, etc. The list of the event(s) is not exhaustive and may be configured by the HES 14 on the node N2.

[0070] The tamper event may trigger particular application(s) to run on the node N2 thereby generating high data traffic. For example, if the node N2 is tampered with magnet or a high voltage, the node N2 may run particular applications(s) to gather data of the electromagnetic field in its vicinity and may send the data to the HES 14 for analysis. Similarly, the security breach may also cause a surge of data traffic sent by the node N2 to the HES 14. For example, in the event that the node N2 has a WiFi module, if a third party attacks the WiFi module and tries to gain access to the device, false information may be injected via the WiFi module to the network 100. The node N2 itself may not be able to distinguish between a tamper event and a security breach, but once the node N2 determines that a volume / rate of data traffic sent by itself has exceeded a threshold or that the volume / rate of data traffic to be sent by itself will exceed the threshold, the node N2 may transform its operation mode from the first mode to the second mode. The mode switching to the second mode allows the node N2 to isolate itself as much as possible from other nodes as it may be experiencing threat. The surge of power load may concern a scenario in which the node N2 incorporates an electricity meter. When the power load on the electricity meter goes beyond a certain threshold, the node N2 may start running analytics applications which can create high volume of traffic on network. The mode switching to the second mode allows the node N2 to execute the high-computing analytics applications, which the node N2 may not be able to do while performing various other functionalities as in the first mode.

[0071] Regarding the interruption in power from an external power supply, it concerns a scenario where the node N2 receives power from the external power supply (e.g., mains AC power), and also include a backup battery. If the node N2 experiences interruption in power from the external power supply, the node N2 relies on battery for a time period until the external power supply is resumed. If the node N2 continues with its full functionality as an FFD in the first mode, the battery may be quickly depleted, thereby causing the node to suddenly become offline and thus bringing temporary disruptions to the mesh network 100. The mode switching to the second mode allows the node N2 to reduce power consumption, thereby prolonging its operation time while using the backup battery. In this scenario, the way the node N2 communicates with other devices in the mesh network may be different between the first and second modes. When the node N2 is powered by battery and operates in the second mode, the node N2 may be sleeping more often as compared to the first mode and waking up at regular intervals. As the node N2 is sleeping more often, its way of maintain synchronization with another FFD may differ significantly.

[0072] The node N2 may detect the occurrence of at least some of the particular event(s) described above. Alternatively, the node N2 may simply send the relevant data to the HES 14 for analysis, and once the HES 14 detects the occurrence of at least one of the particular event(s) based upon the received data from the node N2, the HES 14 may issue the mode-changing command to the node N2 instructing the node N2 to switch to the second mode.

[0073] Following up from step 01 , the processing may proceed to step 02 wherein the node N2 broadcasts a message to its child nodes (e.g., N3 and N5). The message informs the child nodes of the upcoming mode switching of the node N2. The node N2 may switch its operation mode to the second mode only after notifying its child nodes. The purpose of the message is to prompt the child nodes to look for and connect to a new parent node which is different from the node N2. Figure 2 illustrates an exemplary new topology of the mesh network 100 where the previous child nodes N3 and N5 of the node N2 have successfully moved to new parent nodes upon receiving the message. The node N5 is now linked with a new parent node N1 , and the node N3 is now linked with a new parent node N4. The child nodes may perform network / neighbor discovery process as per IEEE 802.15.14 and IETF RFC 6550 (or other standards) to look for suitable parent nodes.

[0074] After broadcasting the message, the node N2 may wait for a predetermined period of time to allow the child nodes to search and move to new parent nodes(s). Upon the expiry of the predetermined period, the processing may automatically proceed to step S2 regardless of whether the child nodes have successfully connected to new parent node(s).

[0075] Alternatively, after broadcasting the message, the node N2 may wait for responses from its child nodes, before switching from the first mode to the second mode (step S2). In the example of Figure 2, the previous child nodes N3 and N5 may send responses to the node N2 to acknowledge that they are now linked with new parent nodes.

[0076] There is a further optional step 03 which may take place between the steps S1 and S2. The optional steps 01 to 03 may take place according to a sequence which is different from the order as shown in Figure 5. For example, the step 03 may be performed before or concurrently with step 01 , between steps 01 and 02, or concurrently with step 02. One or more of the optional steps 01 to 04 may be omitted.

[0077] At step 03, the node N2 determines the presence of critical node(s) within its child nodes. Each of the following nodes may be considered as a critical node:

[0078] (a) a child node that is powered by battery only. Such a node may be referred to as a battery end point (BEP) node (such as a smart gas meter) and typically does not have any routing capability. Because searching and moving to a new parent node is a battery extensive process, it may be desirable to avoid such a battery extensive process on the BEP node. (b) a child node which was previously switched from operating in the first mode to operating in the second mode. Such a child node may be sending heavy traffic to the HES 14 or may be performing intensive applications as described above in relation to the particular events that trigger the mode switching. If the node N2 is going to switch to the second mode, such a child node will have to find a new parent causing temporary disruption to its data transmissions or the running of the intensive applications.

[0079] (c) a child node which cannot find a new parent node within the mesh network 100. Such a child node may respond to the message sent by the node N2 at step 02 and let the node N2 know that it is unable to move to a different parent node.

[0080] In an example, the node N2 may allow the critical node(s) to remain connected to itself even after its mode switching to the second mode, thereby continuing data routing for the critical node(s) in the second mode. Figure 3 illustrates an exemplary new topology of the mesh network 100 where the previous child node N3, being a non-critical node, has moved to a new parent node N4 and the previous child node N5, being a critical node, is allowed to remain linked to the node N2. It would be understood that, in reality, the critical node(s) is typically a small percentage of all the child nodes, and thus allowing the critical node(s) to remain connected to the node N2 still means that the node N2 would have a reduced routing functionality in the second mode as compared to the first mode.

[0081] Alternatively, the node N2 may communicate to the HES 14 about the details of the critical node(s) within its child nodes, and await further instructions from the HES 14. In an example, the HES 14 may instruct the node N2 to remain connected to the critical node(s). Alternatively, depending upon the type of the critical node (c), the HES 14 may instruct some of the critical nodes (e.g., the critical node (a)) to enter into a deep sleep mode, thereby temporarily disconnecting those nodes from other nodes of the mesh network 100.

[0082] Still alternatively, if the node N2 has identified the presence of one or more critical nodes within its child nodes during the first mode, the node N2 may defy the modechanging command from the HES 14, or ignore the occurrence of the events detected at the step 01. In other words, the node N2 may not switch its operation mode from the first mode to the second mode (step S2), in favor of the critical nodes.

[0083] In another example, the critical nodes may still need to migrate to other parent nodes. In that case, step 03 may be omitted.

[0084] After the mode switching of the node N2 at step S2, the node N2 acts as a RFD (as an end node without routing capability) or an enhanced RFD (with a much reduced routing capability by allowing one or more critical nodes to remain connected thereto) in the second mode. It would be understood that while operating in the second mode, the node N2 has a reduced number of child nodes and performs less routing activity as compared to the first mode. The node N2 may also disable some of the applications which are not critical or reduce the frequency of running those applications, which were run normally in the first mode. Such applications include non-critical applications (e.g., which send periodic or non-critical data to the HES 14), and the data sent may include network statistics, load consumption, low priority events, etc. By having a limited routing functionality and reducing the execution of non-critical applications in the second mode, the node N2 can direct some of its resources to performing specialised operations which can be memory / power intensive, or may direct some or all of its bandwidth to transmit high volume of traffic arising from a particular device (e.g., a sensor or a device performing edge intelligence computations) connected to itself or included within itself. This avoids the needs of deploying an additional high-processing device to the mesh network 100, thereby saving the costs of the mesh network 100. In the event that there is an interruption in power from the external power supply of the node N2, by switching from the first mode to the second mode, the node N2 can reduce its power consumption while relying upon battery power. The ability to switch its operation mode allows the node N2 to adapt to conditions and to support particular processing / transmission needs, by changing its behaviour. The behaviour change includes reducing some of the features the node N2 supports like routing, reducing the number of child nodes it supports, and reducing some of the application layer feature etc.

[0085] While operating in the second mode, the node N2 still maintains a communication with its own parent node N1, so that it is reachable to the HES 14 and the central coordinator 10 of the mesh network 100. Once the node N2 switches its operation mode, the node N2 may inform the HES 14 about the change. On the other hand, the HES 14 may send a command to any node of the mesh network 100 enquiring the active mode of the respective node.

[0086] Referring back to the network topology of Figure 1 , assuming that the child node N5 of the node N2 is a BEP node, the child node N5 may automatically perform one of the following actions when it is informed (e.g., by the step 02) that its parent node N2 is going to switch to the second mode: (1) connecting to a new parent node which is different from the node N2, as shown by Figure 2; (2) continuing its connection to the node N2 as a critical node, as shown by Figure 3; (3) entering into a deep sleep mode for a specified duration. The node N5 may try to communicate with the node N2 after the lapse of the specified duration.

[0087] The processing of Figure 5 includes a further optional step S5 where the node N2 is switched from the second mode back to the first mode. After the operation mode of the node N2 is switched to the second mode at the step S2, the node N2 may switch back to the first mode automatically after the lapse of a specified time period. Alternatively, the node N2 may wait for another command from the HES 14 instructing the node N2 to switch back to the first mode.

[0088] The above described mode switching of the node N2 may be performed on an ad-hoc basis, as deemed necessary by the HES 14 or based upon the occurrence of the particular event(s). Alternatively, the above described mode switching of the node N2 may take place periodically (e.g., once a day) as configured by the HES 14 on the node N2.

[0089] While in the embodiments described above the node N2 is selected as an example, it would be understood that any node of the mesh network 100 may be a reconfigurable node that can switch between operating as an FFD and operating as an RFD (or an enhanced RFD) after deployment of the network 100.

[0090] The terms “having”, “containing”, “including”, “comprising” and the like are open and the terms indicate the presence of stated structures, elements or features but not preclude the presence of additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.

[0091] Although the disclosure has been described in terms of preferred embodiments as set forth above, it should be understood that these embodiments are illustrative only and that the claims are not limited to those embodiments. Those skilled in the art will be able to make modifications and alternatives in view of the disclosure which are contemplated as falling within the scope of the appended claims. Each feature disclosed or illustrated in the present specification may be incorporated in the disclosure, whether alone or in any appropriate combination with any other feature disclosed or illustrated herein.

Claims

CLAIMS:

1. A method of operating a mesh network, comprising:operating a node of the mesh network in a first mode, wherein the node operates as a full function device, FFD, in the first mode; andswitching the node from operating in the first mode to operating in a second mode, wherein the node operates with a reduced routing functionality in the second mode as compared to the first mode.

2. The method of claim 1, wherein the node operates as a reduced function device, RFD, in the second mode.

3. The method of claim 1 or 2, wherein operating the node in the first mode comprises:receiving, by the node, data from at least one child node which is wirelessly linked to the node within the mesh network; andsending, by the node, the received data to a central coordinator of the mesh network;wherein one or more of the at least one child node is disconnected from the node when the node operates in the second mode.

4. The method of claim 3, further comprising: before switching the node from operating in the first mode to operating in the second mode,sending, by the node, a message to the at least one child node, wherein the message informs the at least one child node of the switching.

5. The method of claim 4, further comprising: in response to receiving the message,connecting the one or more of the at least one child node to new parent node(s) within the mesh network.

6. The method of any one of claims 3 to 5, further comprising:determining, by the node, that the at least one child node comprises a critical node;wherein the critical node remains connected to the node when the node operates in the second mode.

7. The method of claim 6, wherein the critical node comprises one or more of the following:a child node that is powered by battery only;a child node which was previously switched from operating in the first mode to operating in the second mode; anda child node which cannot find a new parent node within the mesh network.

8. The method of any preceding claim, wherein operating the node in the first mode comprises running, by the node, a first application, and the first application is disabled by the node in the second mode or is run by the node at a lesser frequency in the second mode than in the first mode.

9. The method of any preceding claim, further comprising:receiving, by the node, a mode-switching command from a headend system in communication with the mesh network, wherein the mode-switching command instructs the node to switch from operating in the first mode to operating in the second mode.

10. The method of any preceding claim, further comprising:detecting an occurrence of an event while the nodes operates in the first mode; wherein the switching is performed if the occurrence of the event has been detected.

11. The method of claim 10, wherein the event comprises one or more of the following:a tamper event at the node;a security breach at the node;a volume or a rate of data traffic to be sent by the node exceeding a first threshold;a power load of the node exceeding a second threshold; andan interruption in power from an external power supply, wherein the node is operable to receive power from the external power supply in the first mode.

12. The method of any preceding claim, wherein the mesh network comprises a battery end point, BEP, node, which is a child node of the node in the first mode, and the method further comprises;in response to switching the node from operating in the first mode to operating in the second mode, entering, by the BEP node, into a deep sleep mode.

13. A node for use in a mesh network, comprising:a communication module for communicating with at least one other node of the mesh network; anda controller configured to control the communication module;wherein the controller is configured such that the node is operable to switch its operation mode from a first mode to a second mode, wherein the node is configured to operate as an FFD in the first mode and to operate with a reduced routing functionality in the second mode as compared to the first mode.

14. The node of claim 13, wherein the controller comprises a processor and a memory storing a first firmware supporting the first mode and a second firmware supporting the second mode, and wherein the processor is configured to switch from executing the first firmware to executing the second firmware such that the node switches its operation mode from the first mode to the second mode.

15. The node of claim 13, wherein the controller comprises a processor and a memory storing a single firmware, and wherein the processor is configured to switch from executing the single firmware with a first configuration to executing the second firmware with a second configuration such that the node switches its operation mode from the first mode to the second mode, wherein the second configuration is different from the first configuration.

16. The node of any one of claims 13 to 15, wherein the node is operable to receive power from an external power supply.

17. The node of any one of claims 13 to 16, wherein the node comprises a backup battery for supplying power to the communication module and the controller.

18. The node of any one of claims 13 to 17, wherein the node further comprises a metrology module arranged to measure consumption of a resource and to generate consumption data indicative of the consumption of the resource.

19. A mesh network, comprising:a central coordinator; anda node according to any one of claims 13 to 18.

20. The mesh network of claim 19, further comprising:at least one other node, wherein the node is configured to route data from the at least one other node to the central coordinator when the node operates in the first mode, and is configured to be disconnected from one or more of the at least one other node when the node operates in the second mode.

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