Method for selecting alternative agent in wireless communication network

Abstract

A method (500) of a node (300) for selecting an alternative agent (250) in a wireless communication network (100) to replace a current agent (200), where the node (300) is connected to the wireless communication network (100) via the current agent (200), the method (500) comprising the following steps of the node (300): generating (S501) a list of one or more candidate alternative agents; polling (S502) a neighbor table of the current agent (200) to obtain entries related to one or more candidate alternative agents; maintaining (S503) a list of one or more candidate alternative agents based on feedback from the current agent (200); and selecting (S504) an alternative agent (250) from the list of one or more candidate alternative agents to replace the current agent (200) when the link quality between the node (300) and the current agent (200) decreases below a certain threshold.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications. More particularly, various methods, devices and systems are disclosed herein, which are related to a method for a node to select an alternative agent to replace its current agent to access a wireless communication network. Background Art

[0002] There is a growing trend in the professional lighting market towards connected lighting systems, which enable a wide variety of new features, such as (remote) scheduling, energy monitoring, sensor-based lighting control, and asset management. In many cases, these systems are installed in existing buildings, in which case a wireless network is preferred to avoid having to deploy new cables (for lighting control) through the ceiling. Examples of such wireless network protocols widely used in current practice are open standards such as Zigbee, Thread, BLE, BLE Mesh, Wi-Fi, Wi-Fi Direct, as well as various proprietary network implementations built on top of the IEEE 802.15.4, IEEE 802.15.1 or IEEE 802.11 standards.

[0003] Zigbee, Thread, and Bluetooth mesh are examples of wireless networks for IoT applications. They provide low-latency, low-rate services that enable messages to be passed between, for example, a light switch and one or more luminaires. Mesh networking provides great flexibility and scalability to the system. However, when a problem is detected in such a network, a common repair mechanism is based on broadcasting. In smaller networks, this works well. In larger networks, broadcasting results in quite a lot of messages, as the number of messages required for broadcasting scales linearly with the size of the network. In many cases, the flooding of information can even exacerbate the original problem.

[0004] End devices (such as Zigbee end devices) communicate through a parent node or a proxy node, but sometimes an end device may lose its connection to a proxy node, such as when the proxy node loses power. This can also happen due to interference, or simply because too many messages are sent in the network, so that the message from the end device cannot reach the parent node or proxy node. To search for a new proxy, the typical process is to send out a beacon request. All routers that receive the beacon request will respond. Using the Zigbee standard as an example, since the beacon request uses 0xFFFF as its panID, this means that all routers within radio range on the same channel will respond. Note that in an apartment building, this will include router devices in the network from neighbors on the same channel (and most systems only use the four main Zigbee channels). When the connection to the parent node is lost due to a lot of traffic in the network, the beacon request to find a new parent node will add many new messages to the already overloaded network. This can even cause other end devices to lose their connection to the parent node or proxy node, causing a cascading effect.

[0005] US2016212010A1 relates to a node device that can be connected to a mesh network. The node device includes a selector, an builder, a communication unit, and a reselector. The selector selects a node to be used as a connection-destination candidate node from among adjacent nodes. The builder establishes a security association with the node selected by the selector. The communication unit receives a connection-destination candidate node list via the node with which the builder establishes a security association. The reselector newly selects a connection-destination node based on the connection-destination candidate node list received by the communication unit.

[0006] US2006274671A1 relates to a method and apparatus for operating a wireless network including redundant communications, wherein redundantly connected nodes are discussed, including addressing methods and methods of creating groups for such redundant communications. Summary of the invention

[0007] In a distributed network, some nodes are end nodes or leaf nodes that rely on other nodes (proxy nodes, router nodes, or parent nodes) to relay messages to them. A problem may arise when those end nodes and / or leaf nodes lose connectivity to the distributed network: the process of finding a new parent node or a new proxy may result in significant additional traffic to the network. The problem becomes even more severe when the network scales up and / or nodes are deployed at a high density.

[0008] In view of the above, the present disclosure is directed to methods and apparatus for providing mechanisms associated with efficient alternative parent node or proxy discovery. An end node or leaf node prepares and maintains a list of candidate alternative proxies for use, rather than initiating a new process after the connection to the proxy node or parent node has been lost. More particularly, the objects of the present invention are achieved by a method as claimed in claim 1 and a node as claimed in claim 12.

[0009] According to a first aspect of the present invention, there is provided a method for a node to select an alternative proxy to replace a current proxy in a wireless communication network. The node is connected to the wireless communication network via the current proxy, and the method comprises the following steps of the node:

[0010] - generating a list of one or more candidate replacement agents, wherein the list is sorted in an initial order;

[0011] - polling the neighbor table of the current agent to obtain entries associated with one or more candidate replacement agents;

[0012] - based on feedback from the current agent, maintaining a list of one or more candidate replacement agents; and

[0013] - when the link quality between the node and the current agent drops below a certain threshold, selecting an alternative agent from a list of one or more candidate alternative agents to replace the current agent;

[0014] One or more candidate replacement agents are ranked to be selected as replacement agents based on both feedback from the current agent and an initial order according to which the list is generated.

[0015] Note that a certain threshold on link quality may be an application dependent parameter. For example, depending on the data rate to be supported, a node may accept different link quality levels. The higher the required data rate, the more stringent the link quality requirements.

[0016] The node may be an end node or a leaf node, which communicates only through its parent node or proxy node and cannot relay messages intended for other nodes. When the link quality between the node and the current proxy drops below a certain threshold or the link is even completely lost, it is important that the node can find an alternative proxy as quickly as possible to connect to the wireless network again. Therefore, it is proposed that the node should prepare a list of alternative proxies in advance. And then, in the event that the current proxy should be replaced, the node can quickly try to connect to a new proxy node selected from the list.

[0017] Therefore, it is also necessary to keep the list of alternative agents up to date, i.e., adapt to any changes in the topology around the node. Terminal devices that do not have strict requirements on power consumption can choose to keep their radios always on. Such nodes may then be able to overhear other traffic on the network and obtain updates on any changes in the surrounding topology. However, for most battery-operated devices, it is expected that the radio will be turned off when they are idle. This also means that they will not be able to overhear other traffic on the network and will not be able to obtain updates on any changes in the topology. Therefore, it is proposed that the node updates its own list of alternative agents using the neighbor table of its current agent or parent node, assuming that the neighbor information is frequently refreshed by the agent node or parent node. For example, whenever a proxy node or parent node receives any frame from a corresponding neighbor, a neighbor table entry can be updated.

[0018] This is particularly beneficial when the network is deployed with a high density of nodes. And then, since the current agent is near the node, there is a high probability that at least some of the alternative agents for the node will also appear in the neighbor table of the current agent.

[0019] Polls may be sent alone, or may be combined with regular packets sent by a node to the current agent.

[0020] The whole process can be triggered when a node is deployed in the network, or when it loses connection with its current proxy node or parent node.

[0021] Advantageously, the method further comprises the following steps:

[0022] - send a beacon request; and

[0023] - receiving one or more beacon responses;

[0024] The list of one or more candidate replacement proxies is generated based on the one or more beacon responses.

[0025] As an option, the initial list of candidate replacement agents is generated based on the detection process of the node itself. For example, the node first sends a beacon request, and then based on the responses to the beacon request from its neighbors, the node can create such a list based on certain selection criteria, such as the received signal strength indicator (RSSI) of the responses.

[0026] The detection process may be performed by a node after joining the wireless communication network, or when it loses its connection with the current proxy, or when it fails to reconnect to an alternative candidate proxy.

[0027] Alternatively, the initial list of one or more candidate replacement agents may be generated based on input from the outside (such as instructions received from a network entry initialization device, or configuration commands received from an application layer).

[0028] In another option, the node may first connect with a proxy node or a parent node and generate an initial list by reading the neighbor table of the proxy node or the parent node.

[0029] Preferably, the method further comprises the step of sending a request (such as a rejoin request) to the selected alternative proxy to establish a new connection to the wireless communication network. If unsuccessful, the node may select another alternative proxy from a candidate list (the list comprising one or more candidate alternative proxies) and send the request again. If still unsuccessful, the node may continue the process by cycling to another alternative proxy on the list. The node may also restart the entire process by the following steps:

[0030] - Send a beacon request;

[0031] - Selecting a proxy based on the beacon response; and

[0032] - generating a new candidate list comprising identifiers of senders of a subset of received beacon responses, or of all received beacon responses, except the one that has been selected as the current proxy.

[0033] Advantageously, the method further comprises the step of storing the list of one or more candidate replacement agents in a non-volatile memory.

[0034] Non-volatile memory (NVM), or non-volatile storage, is a type of memory that retains stored information even after power is removed. In contrast, volatile memory requires constant power to retain data.

[0035] For nodes powered by batteries or even by energy harvesting, it is possible that the nodes lose power when they are idle. In order to maintain a candidate list for this type of node, it is therefore beneficial to store the candidate list in non-volatile memory.

[0036] Advantageously, one or more candidate replacement agents are ranked for selection as replacement agents based both on feedback from the current agent and the initial order in which the list was generated.

[0037] Since the initial order of the candidate list may be determined based on the link performance between the node and its neighbors estimated by the node itself, such as based on the received beacon response signal-to-noise ratio indicator (RSSI), the initial order may represent a more accurate topology scenario at that moment.

[0038] The feedback from the current agent reflects the neighbor information centered on the current agent. Although the node and the current agent are also nearby, the neighbor information contained in the feedback still includes an offset caused by the distance between the node and the current agent. However, since the current agent updates its neighbor information much more frequently, it can well reflect the changes in topology over time.

[0039] Therefore, it is considered beneficial to combine the information from the feedback and the initial order to determine the most favorable alternative agent.

[0040] In one example, a neighbor table of a current agent is polled to verify one or more link quality indicators associated with one or more candidate replacement agents.

[0041] The neighbor table of the current agent may simply be polled to check if the candidate replacement agent is on the neighbor table of the current agent. It may also be beneficial to obtain more information related to the entry in the neighbor table, such as checking a link quality indication between the current agent and the candidate replacement agent. Additional parameters may also be queried as disclosed below.

[0042] Advantageously, the alternative agent is selected based on one or more of the following parameters:

[0043] · Link quality parameters between the node and the alternative proxy;

[0044] · Link quality parameters between the current proxy and the alternative proxy;

[0045] The link cost parameter between the node and the alternative proxy;

[0046] · Link cost parameter between the current agent and the alternative agent;

[0047] Reliability performance between this node and alternative agents;

[0048] ·Reliability performance between the current agent and alternative agents;

[0049] Application requirements;

[0050] The history of past use of alternative proxies by this node as proxies.

[0051] Link quality parameters can be defined in different ways. For example, a link quality indicator (LQI) can be used to indicate the quality of data packets received by a receiver. Received signal strength (RSS) can be used as a measure of signal quality. RSS is a measure of the total energy of the received signal. The ratio of the expected signal energy to the total in-band noise energy (signal-to-noise ratio or SNR) is another way to judge signal quality. Therefore, the link quality parameter can be one of LQI, RSS or SNR.

[0052] The reliability performance between the node and the substitute agent can be estimated by the historical success rate of the node receiving a response from the substitute agent or the historical success rate of the node establishing a child-parent connection with the substitute agent.

[0053] The reliability performance between the current agent and the alternative agent can be estimated by considering the number of times the alternative parent node appears in the feedback.

[0054] The reliability performance between the node and the replacement agent can be estimated based on the duration since the node last detected the replacement parent node.

[0055] Application requirements may also specify a certain type of proxy, or a minimum data rate required. Correspondingly, such requirements can be translated into additional criteria for determining priorities when selecting alternative proxies.

[0056] Similarly, the initial order of the candidate list can be determined by the node according to the following order:

[0057] · Link quality parameters between the node and the alternative proxy;

[0058] The link cost parameter between the node and the alternative proxy;

[0059] Reliability performance between this node and alternative agents;

[0060] Application requirements;

[0061] The history of past use of alternative proxies by this node as proxies.

[0062] Advantageously, the feedback from the current agent comprises a subset of the contents of the neighbor table.

[0063] To reduce communication overhead, it is encouraged to include only relevant information in the feedback, rather than the entire neighbor table or all entries in the neighbor table associated with one or more candidate replacement agents. For example, in the feedback, the current agent may only send information about the address and link cost parameters associated with each single candidate replacement agent.

[0064] In one embodiment, the step of polling the neighbor table of the current agent is performed periodically.

[0065] In this option, polling can be scheduled according to regular time intervals. The time interval can be set according to the power budget of the node, the stability of the link between the node and the current agent, application requirements, or another parameter. For example, if relatively stringent requirements are set for the reliability of the connection between the node and the wireless network, such as for time-critical applications, the time interval is preferably set shorter to update more frequently about any changes in the network topology. In other examples, the node can also adjust the time interval to adapt to the remaining battery power, requests from applications, or changes in the stability of the link between the node and the current agent.

[0066] In another embodiment, the step of polling the neighbor table of the current agent is performed based on a triggering event.

[0067] The trigger event may be a button press, a motion event, or a control command. Such trigger-based polling provides lower latency than periodic polling, especially because such button presses, motion events, or control commands occur sporadically without a fixed rhythm.

[0068] Beneficially, each of the one or more candidate replacement agents is identified by a unique identifier in the list.

[0069] Advantageously, the unique identifier is a network address, a Media Access Control (MAC) address or an IP address of the candidate replacement agent.

[0070] A network address (sometimes also referred to as an NwkAddr, short address, or node address) is typically a 16-bit number that is used to uniquely identify a specific node on a network. A network address is typically assigned to a node when it joins the network.

[0071] A Media Access Control address (MAC address) is a unique identifier typically assigned by a device manufacturer and is therefore often referred to as a burned-in address, or Ethernet hardware address, hardware address, or physical address. According to the BLE standard, an IEEE 802 MAC address includes a 48-bit address space. According to the Zigbee standard, a MAC address (also called an IEEE address, long address, or extended address) is a 64-bit number that uniquely distinguishes the device from all other ZigBee devices in the world.

[0072] For a node in a wireless network, the MAC address is usually mapped to the network address, but the two can be used in parallel in different situations.

[0073] In another option, a node can be addressed by an Internet Protocol address (IP address). IP addresses provide two main functions: network interface identification and location addressing. Internet Protocol version 4 (IPv4) defines IP addresses as 32-bit numbers, while the newer version Internet Protocol version 6 (IPv6) defines 128-bit IP addresses.

[0074] Preferably, the wireless communication network is based on one of the Zigbee standard, the Thread standard or the BLE standard.

[0075] The Zigbee standard is widely adopted in home automation and lighting control applications. The Zigbee network layer natively supports both star and tree networks, and also supports general mesh networking. Powerful topology control provides great flexibility in control systems, especially for reaching destination nodes far away from the source node using direct links.

[0076] ZigBee specifies three different device types: ZigBee Coordinator (ZC), ZigBee Router (ZR), and ZigBee End Device (ZED). These three devices play different roles in a ZigBee network. Zigbee Routers (ZR) pass data between devices and / or coordinators. Zigbee End Devices (ZED) provide only basic functionality. ZEDs are leaf nodes. They communicate only through their parent node, and unlike router devices, they cannot relay messages intended for other nodes. They do not participate in any routing. End devices rely on their parent routers to send and receive messages. With respect to IEEE 802.15.4, ZCs and ZRs are full function devices (FFDs), while ZEDs are reduced function devices (RFDs).

[0077] Thread is a low-power mesh networking technology based on IPv6. Thread uses the IEEE802.15.4 wireless protocol with mesh communication, as does the Zigbee system. The difference is that Thread is IP addressable with cloud access.

[0078] According to a second aspect of the present invention, a node is provided. The node is configured to be connected in a wireless communication network via a current proxy. The node comprises:

[0079] - a controller configured to generate a list of one or more candidate replacement agents, wherein the list is sorted in an initial order; and

[0080] - a radio configured to poll a neighbor table of a current agent for entries associated with one or more candidate replacement agents, and to receive feedback from the current agent;

[0081] wherein the controller is further configured to maintain a list of one or more candidate replacement agents based on feedback from the current agent; and when the link quality between the node and the current agent decreases below a certain threshold, select a replacement agent from the list of one or more candidate replacement agents to replace the current agent;

[0082] One or more candidate replacement agents are ranked to be selected as replacement agents based on both feedback from the current agent and an initial order according to which the list is generated.

[0083] The controller or processor may include a conventional microprocessor, an application specific integrated circuit (ASIC), or a field programmable gate array (FPGA).

[0084] The node may be battery powered, or even powered by energy harvesting, and the node may then power down the controller and / or radio when it is idle.

[0085] Advantageously, the radio is further configured to send a beacon request; and receive one or more beacon responses; wherein the list of one or more candidate replacement agents is generated based on the one or more beacon responses.

[0086] The initial candidate list may be generated by the node through a discovery process by sending a beacon request and receiving one or more beacon responses. The initial candidate list may also be generated based on external input (such as instructions received from a network entry initialization device, or configuration commands received from an application layer).

[0087] Beneficially, the controller is further configured to rank the one or more candidate replacement agents to select the replacement agent based both on feedback from the current agent and on the initial order in which the list was generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] In the drawings, similar reference numerals are used throughout the different Figure 1 Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

[0089] Figure 1 An example of a wireless communication network is shown;

[0090] Figure 2 A flow chart showing a method according to the present invention; and

[0091] Figure 3 A flow chart showing another example of a method according to the present invention is shown. DETAILED DESCRIPTION

[0092] The embodiments set forth below represent information to enable those skilled in the art to practice these embodiments. Upon reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize applications of these concepts not particularly addressed herein.

[0093] For smart buildings, smart industry, smart homes or smart lighting control, mesh networking provides great flexibility and scalability to the system. However, when a problem is detected in such a network, the common repair mechanism is based on broadcasting. In smaller networks, this works well. In larger networks, broadcasting leads to a large number of messages, because the number of messages required for broadcasting is linearly proportional to the network size. In many cases, the flooding of information can even exacerbate the original problem.

[0094] In a distributed network, some nodes are end nodes or leaf nodes that rely on other nodes (proxy nodes, router nodes, or parent nodes) to relay messages to them. When those end nodes and / or leaf nodes lose connection to the distributed network, a problem may arise: the process for finding a new parent node or a new proxy may result in significant additional traffic to the network. Taking a Zigbee network as an example, a Zigbee end device communicates through its parent node, but the end device may lose its connection to the parent node, such as when the parent node loses power. This may also happen due to interference, or simply because so many messages are sent in the network that the message from the end device does not reach the parent node. In order to search for a new parent node, the Zigbee process will send out a beacon request. All routers that receive the beacon request will respond. Since the beacon request uses 0xFFFF as its panID, this means that all routers within radio range on the same channel will respond. Note that in an apartment building, this will include router devices in the network from neighbors on the same channel (and most systems only use the four main Zigbee channels). When the connection to the parent node is lost due to a large amount of traffic in the network, it is clear that beacon requests to find a new parent node will add many new messages to the already overloaded network. This can even cause other end devices to lose their parent connection, resulting in a cascading effect.

[0095] Therefore, it is important to provide a mechanism that enables end devices to find new proxies more efficiently without introducing a large amount of traffic to the network.

[0096] Figure 1An example of a wireless communication network 100 is shown. The wireless communication network 100 may be based on the Zigbee standard, the Thread standard, or the BLE standard. The wireless communication network 100 includes a plurality of devices forming a mesh network. Depending on the physical properties of individual devices, they may play different roles in the network. For example, in a Zigbee network, a device may play one of three roles: a ZigBee coordinator (ZC), a ZigBee router (ZR), and a ZigBee end device (ZED). The Zigbee router (ZR) transfers data between devices and / or coordinators. The Zigbee end device (ZED) provides only basic functionality. ZEDs are leaf nodes. They communicate only through their parent nodes, and unlike router devices, they cannot relay messages intended for other nodes. They do not participate in any routing. End devices rely on their parent routers to send and receive messages. With respect to IEEE 802.15.4, ZC and ZR are full function devices (FFDs), while ZEDs are reduced function devices (RFDs).

[0097] like Figure 1 As shown in , the node 300 is an end node or leaf node that relies on other nodes (proxy nodes, router nodes or parent nodes 200, 250) to relay messages to them. The binding between the node 300 and its current proxy or parent node is shown by the dashed line diagram. As can be seen from the figure, depending on the density of device deployment in the wireless communication network 100, each end node or leaf node 300 can be surrounded by more than one device 200, 250 that can act as a proxy or parent node for it.

[0098] Conventionally, when a node 300 loses its connection with its proxy node or parent node 200, it will initiate a new discovery process by sending a beacon request. In order to reduce the chance of sending a beacon request, it is disclosed in the present invention that the terminal device 300 will maintain a list of alternative parent nodes 250. When the terminal device 300 loses its connection with its parent node 200, it can select one of the alternative parent nodes 250. Instead of sending a beacon request, it directly sends a rejoin request to the alternative parent node 250. In the case where the alternative parent node 250 does not send a rejoin response (for example, because it is offline or has a complete child table), the terminal device 300 selects the next one in its candidate alternative parent node list and tries again. Repeat this process until a successful rejoin is achieved, or the end of the candidate list is reached, or the node 300 decides not to traverse the entire candidate list, after which a normal beacon request is sent out.

[0099] Typically, when an end device 300 first joins the network, it sends a beacon request. From this beacon request, a suitable parent node 200 is selected. When multiple suitable beacon responses are received, it is proposed to store a list of potential replacement parent nodes or proxy nodes (preferably in permanent storage to survive a device reboot or power outage).

[0100] When the connection with the parent node 200 is lost (for example, because the user powered off the parent node 200), an alternative parent node 250 is selected. In order to find an alternative parent node 250, the link cost is used to select a nearby candidate agent. Since the network can change over time, or the user can also power off one or more of the alternative parent nodes, monitoring the link quality indicator (LQI) or another parameter representing topology information can be an option. The terminal device can poll the neighbor table of its parent node to verify the availability and LQI of the candidate alternative parent node. Polling can be performed periodically (such as at a relatively low frequency), but can also be triggered by an event (such as after a button press or motion event). As an example, when a user presses a button on a switch terminal device, a message to control the light is first sent, and then the neighbor table of the parent node is read. Since conventional Zigbee mgmt-lqi messages require up to 13 reads to obtain a complete neighbor table, it is beneficial to implement a vendor-specific version of the neighbor table read. By returning only a subset of the neighbor table, such as only information related to network addresses and link costs, the full 26-entry neighbor table can fit into a single message, further reducing communication overhead.

[0101] The selection of a suitable replacement parent node may depend on link cost, the last time the replacement parent node was seen, or the number of times the replacement parent node has not been detected (i.e. powered down). This has an added benefit, as selecting a more suitable parent node will also reduce the chance of having connection problems in the future. When a new parent or proxy node is selected, the end device can join it by sending a (secure) rejoin request, thus avoiding the need to send a beacon request.

[0102] As an additional improvement, the availability of alternative parent nodes can be sent to the gateway device. For example, using a manufacturer-specific feature or a standard-specific feature reporting mechanism, such as the Zigbee feature reporting mechanism. In this way, the gateway can monitor whether the end device has the correct parent node connection and a sufficient number of available alternatives. The list of alternative parent nodes can also be updated in the event that the end device receives a beacon response on other occasions besides when joining the network.

[0103] The node 300 of the present invention can be embedded, coupled to, or connected to another electronic component or device for smart building control, smart home, smart industry, smart lighting control, or another IoT application. As an example, the electronic component or device can be a light switch, a thermostat, an electric meter, a remote controller, or another device connected to a wireless network. Note that this list is non-limiting and the electronic component or device can be another device used in a similar or related context.

[0104] Figure 2 A flow chart of a method 500 of a node 300 is shown, the method 500 being used to select an alternative proxy 250 to replace a current proxy 200 in a wireless communication network 100. The node 300 is connected to the wireless communication network 100 via the current proxy 200. The method 500 comprises the following steps of the node 300:

[0105] - In step S501, a list of one or more candidate replacement agents is generated;

[0106] - In step S502, polling the neighbor table of the current agent 200 to obtain entries related to one or more candidate replacement agents;

[0107] - in step S503, maintaining a list of one or more candidate replacement agents based on feedback from the current agent 200; and

[0108] In step S504 , when the link quality between the node 300 and the current agent 200 drops below a certain threshold, a replacement agent 250 is selected from a list of one or more candidate replacement agents to replace the current agent 200 .

[0109] Figure 3 A flowchart of another example of a method 500 according to the present invention is shown. Figure 2 In addition to the basic steps shown in FIG. 5 , method 500 may include the following steps: Figure 3 The method 500 may also include a node 300:

[0110] - in step S505, sending a beacon request; and

[0111] - In step S506, receiving one or more beacon responses;

[0112] And generating a list of one or more candidate replacement proxies based on the one or more beacon responses.

[0113] The method according to the present invention can be implemented on a computer as a computer-implemented method, or in dedicated hardware, or in a combination of both.

Claims

1. A method (500) for selecting an alternative proxy (250) to replace a current proxy (200) in a wireless communication network (100) by a node (300), wherein the node (300) is connected to the wireless communication network (100) via the current proxy (200), the method (500) comprising the following steps of the node (300): - generating (S501) a list of one or more candidate replacement agents, wherein the list is sorted in an initial order; - polling (S502) the neighbor table of the current agent (200) to obtain entries associated with one or more candidate replacement agents; - based on feedback from the current agent (200), maintaining (S503) a list of one or more candidate replacement agents; and - when the link quality between the node (300) and the current agent (200) decreases below a certain threshold, selecting (S504) a replacement agent (250) from a list of one or more candidate replacement agents to replace the current agent (200); One or more candidate replacement agents are ranked for selection as replacement agents (250) based both on feedback from the current agent (200) and the initial order in which the list was generated.

2. The method (500) according to claim 1, further comprising the node (300): - Send (S505) a beacon request; and - receiving (S506) one or more beacon responses; The list of one or more candidate replacement proxies is generated based on the one or more beacon responses.

3. The method (500) according to claim 1 or 2, further comprising: - Storing (S507) a list of one or more candidate replacement agents in a non-volatile memory (330).

4. The method (500) of any preceding claim, wherein a neighbor table of a current agent (200) is polled to verify one or more link quality indications associated with one or more candidate replacement agents.

5. The method (500) of any one of the preceding claims, wherein the substitute agent (250) is selected based on one or more parameters among: • Link quality parameters between the current proxy (200) and the replacement proxy (250); · link cost parameters between the node (300) and the surrogate agent (250); · a link cost parameter between the current proxy (200) and the replacement proxy (250); Reliability performance between nodes (300) and substitute agents (250); Reliability performance between the current agent (200) and the replacement agent (250); Application requirements; • History of past use of the replacement agent (250) as a proxy by the node (300).

6. The method (500) of any preceding claim, wherein the feedback from the current agent (200) comprises a subset of the contents of the neighbor table.

7. The method (500) according to any of the preceding claims 1-6, wherein the step of polling the neighbor table of the current agent (200) is performed periodically.

8. The method (500) according to any of the preceding claims 1-6, wherein the step of polling the neighbor table of the current agent (200) is performed based on a triggering event.

9. The method (500) of any preceding claim, wherein each of the one or more candidate replacement agents is identified by a unique identifier in the list.

10. The method (500) of claim 9, wherein the unique identifier is a short network (100) address or a Media Access Control (MAC) address of the candidate replacement agent (250).

11. The method (500) according to any of the preceding claims, wherein the wireless communication network (100) is according to one of the Zigbee standard, the Thread standard or the BLE standard.

12. A node (300) configured to connect in a wireless communication network (100) via a current proxy (200), the node (300) comprising: - a controller (310) configured to generate a list of one or more candidate replacement agents, wherein the list is sorted in an initial order; and - a radio (320) configured to poll a neighbor table of a current agent (200) for entries associated with one or more candidate replacement agents, and to receive feedback from the current agent (200); wherein the controller is further configured to maintain a list of one or more candidate replacement agents based on feedback from the current agent (200); and when the link quality between the node (300) and the current agent (200) decreases below a certain threshold, select a replacement agent (250) from the list of one or more candidate replacement agents to replace the current agent (200); The controller is further configured to rank one or more candidate replacement agents based on both feedback from the current agent (200) and an initial order in which the list is generated to select a replacement agent (250).

13. The node (300) of claim 12, wherein the radio is further configured to send a beacon request; and receiving one or more beacon responses; The list of one or more candidate replacement proxies is generated based on the one or more beacon responses.

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