Solution for source routing information distribution for wireless mesh networks

Abstract

The present invention relates to a distribution system (200). The system (200) includes a first communication device (202) and one or more second communication devices (204a to 204n) that are associated members of the first communication device (202). The first communication device (202) is configured to transmit source routing information to at least one of the second communication devices (204a to 204n). The source routing information includes source routing control information and a source routing identifier. In response to receiving source routing information, each second communication device (204a to 204n), which is a router device (104b), is configured to determine, based on the source routing control information, whether to repeat the received source routing information to its member device (206a to 206n) using the identifier of the second communication device (204a to 204n) set as the source routing identifier, or to repeat the received source routing information to its member device (206a to 206n) using the source routing identifier of the received source routing information. The present invention also relates to a distribution method for a wireless mesh network (102), a wireless communication device, a computer program, and a computer-readable medium.

Description

Technical Field

[0001] The present invention generally relates to the technical field of wireless mesh networks. In particular, the present invention relates to source routing information distribution in wireless mesh networks.

Background Art

[0002] In a wireless mesh network, different downlink routing (i.e., traffic from an external backend system to a target device belonging to the wireless mesh network) solutions can be divided into the following different high-level categories, namely, downlink flooding, routing tables, and source routing.

[0003] In the downlink flooding solution, downlink data packets are flooded in the downlink direction to all possible parts of the wireless mesh network in order to reach the target device of the data packet. Each router device in the wireless mesh network can potentially have no child devices and can limit the flooding to its member devices that are not the target of the packet. For example, this is the current downlink routing solution in Digital European Cordless Telecommunications (DECT-2020 NR) Release 1. The advantage of the downlink flooding solution is that the solution is simple and reliable, and changes in the network topology do not affect routing, so no routing table or complex routing logic is required, and no signaling is required to update routing information. The disadvantage of the downlink flooding solution is the high overhead due to flooding because each downlink data packet may be transmitted unnecessarily through multiple, and even most wireless links of the network.

[0004] In a routing table solution, each router device in a wireless mesh network maintains a routing table containing the addresses of devices below the router device and the corresponding next-hop addresses of those devices. Various methods exist for obtaining entries into and maintaining the routing table. For example, a device may send an explicit packet to update the routing table, or a router device may implicitly learn from uplink data traffic. The routing table is complete and can always be updated. Alternatively, the routing table can be partial. In the case of a partial routing table, a router device falls back to downlink flooding if it cannot find the target next-hop address in the routing table for a packet being forwarded. The advantage of a routing table solution is that flooding can be individually and efficiently limited by a single router device, as each router device can independently decide to fall back to flooding if updated information is not available in the routing table. While the routing table can be implicitly updated from all uplink packets, it is not necessary to continuously update the routing table when there is no data packet activity. Therefore, a routing table routing solution works efficiently when there is bidirectional traffic between a single device in a wireless mesh network and the backend system. Furthermore, an advantage of routing table routing solutions is that they do not increase packet overhead.

[0005] One drawback of routing table solutions is the memory consumption of the router devices, as each router device needs to maintain the next-hop address for each target address. Since more target devices lie beneath these router devices closer to the gateway device, memory consumption increases in routing table solutions for router devices closer to the gateway device than for router devices further away in the network topology. The gateway device transmits data received from backend systems to the wireless mesh network. Also, when partial routing tables are used, the table space is more likely to run within router devices closer to the gateway in the network topology, and actually selecting the correct next-hop and avoiding flooding provides a significant overhead benefit of avoiding flooding.

[0006] In a source routing solution, each source device stores the complete route to the target device and appends all next-hop addresses to the protocol header of the transmitted packet, i.e., the protocol data unit (PDU), so that the complete route from the source device to the target device is included in the transmitted packet. In the downlink direction, this means that the source device of a downlink data packet destined for the wireless mesh network, such as a sink device or gateway device, maintains a list of next-hop addresses to each device down it and includes these addresses in all transmitted downlink PDUs. The advantage of the source routing solution compared to a routing table solution is that the protocol header of the received PDU contains the next-hop address of the PDU to which the router device should forward the received PDU, so the router device does not need to have extra memory for routing. Since the PDU contains the complete route, there is no need to flood data into the wireless mesh network, thus avoiding the overhead of flooding routing solutions.

[0007] The drawbacks of source routing solutions are the overhead introduced with each transmitted packet, which increases as the number of hops increases. Secondly, route changes must be notified to and maintained by the source device even if there are no packets to deliver. Therefore, the more devices and hops present in a wireless mesh network, the more route update messages there are, introducing more packet overhead and reducing the benefits of avoiding flooding. In addition, with source routing solutions, all route update messages pass through those router devices, so even if the route change has no effect whatsoever on how downlink PDUs are routed from those router devices, i.e., even if the route change occurs at the bottom of the network topology, the signaling load of route update messages is concentrated on the gateway devices of the wireless mesh network and the devices connected to those gateway devices.

[0008] Furthermore, source routing solutions can easily result in extremely high route update loads, for example, when a large number of devices begin to malfunction and cause resets, or when the number of moving devices or changes in channel states increase.

[0009] Each of the different downlink routing solutions described above has its own limitations and advantages. Therefore, further routing solutions for wireless mesh networks need to be developed. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The following is a simplified overview to provide a basic understanding of several aspects of various embodiments of the invention. This overview is not a comprehensive summary of the invention. It is not intended to identify the main or important elements of the invention or to describe its scope. The following overview merely presents some of the concepts of the invention in a simplified form as a prelude to a more detailed description of exemplary embodiments of the invention.

[0011] An object of the present invention is to provide a distribution system, distribution method, wireless communication device, computer program, and computer-readable medium for wireless mesh networks. Another object of the present invention is that the distribution system, distribution method, wireless communication device, computer program, and computer-readable medium for wireless mesh networks enable the distribution of source routing information to reduce the number of registrations.

[0012] The object of the present invention is achieved by a distribution system, distribution method, wireless communication device, computer program, and computer-readable medium as defined by each independent claim. [Means for solving the problem]

[0013] According to a first embodiment, a distribution system for a wireless mesh network including a plurality of communication devices is provided, the system including a first communication device and one or more second communication devices which are associated members of the first communication device, the first communication device and one or more second communication devices which belong to a plurality of communication devices of a wireless mesh network, the first communication device is configured to transmit source routing information to at least one of the one or more second communication devices in order to distribute at least one function of hop-limited downlink source routing, the source routing information includes source routing control information and a source routing identifier which indicates the latest hop router device participating in hop-limited downlink source routing, and in response to receiving source routing information from the first communication device, each second communication device which is a router device is configured to determine, based on the source routing control information, whether to repeat the received source routing information to its member device using the identifier of the second communication device set in the source routing identifier, or to repeat the received source routing information to its member device using the source routing identifier of the received source routing information. The first communication device may be a sink device configured to transmit source routing information by broadcasting a beacon message containing source routing information to all second communication devices, or by unicasting a control message containing source routing information to at least one of the one or more second communication devices.

[0014] Alternatively, the first communication device may be a router device configured to transmit source routing information to at least one second communication device by broadcasting a beacon message containing source routing information or by unicasting a control message containing source routing information.

[0015] Source routing control information may include a source routing hop limit value and a hop count value representing the number of hops covered by hop-limited downlink source routing. In response to receiving source routing information from a first communication device, each second communication device, which is a router device, may be configured to compare the hop count value of the received source routing information with the source routing hop limit value of the received source routing information. If the hop count value does not meet the source routing hop limit value, it may increment the hop count value by 1, set the identifier of the second communication device to the source routing identifier, and transmit the received source routing information to its member device. Alternatively, if the hop count value meets the source routing hop limit value, it may transmit the received source routing information, including at least the source routing identifier, to its member device.

[0016] Alternatively, the source routing control information of the source routing information may include a source routing hop limit value representing the number of hops covered by the hop-limited downlink source routing, and each second communication device, which is a router device, may be configured to, in response to receiving source routing information from a first communication device, decrease the source routing hop limit value of the received source routing information by 1 if the source routing hop limit value of the received source routing information is greater than 0, set the identifier of the second communication device to the source routing identifier, and transmit the received source routing information to its member device, or, otherwise, transmit the source routing information to its member device, which includes at least the source routing identifier of the received source routing information.

[0017] When each second communication device changes its association from a first communication device to a third communication device belonging to a plurality of communication devices in a wireless mesh network, the second communication device may be configured to compare the source routing identifier included in the source routing information received from the third communication device with the source routing identifier included in the source routing information received from the first communication device, and if the source routing identifier included in the source information received from the first communication device is different from the source routing identifier included in the source routing information of the third communication device, send a registration message to the third communication device in order to route the registration message to the sink device, or if the source routing identifier included in the source information received from the first communication device corresponds to the source routing identifier included in the source routing information of the third communication device, define that the existing registration is valid.

[0018] Source routing information may further include validity time data, and each second communication device may be configured to send registration messages to the first communication device in order to route the registration messages to the sink device according to the validity time data.

[0019] In response to receiving a downlink data packet from a first communication device, which includes source routing path data and an identifier for the destination device of the downlink data packet, each second communication device may be configured to unicast the downlink data packet to the member device of the second communication device if the source routing path data includes an identifier for a member device of the second communication device, or to unicast the downlink data packet to the member device if the identifier for the destination device corresponds to an identifier for a member device of the second communication device, or, otherwise, to send the downlink data packet to all of its router member devices in order to route the downlink data packet to the destination device.

[0020] The first communication device may be configured to periodically transmit source routing information.

[0021] According to a second embodiment, a distribution method for a wireless mesh network is provided, the method comprising: a step of a first communication device transmitting source routing information to at least one second communication device which is an associated member of the first communication device for distributing at least one function of hop-limited downlink source routing, wherein the source routing information includes source routing control information and a source routing identifier indicating the most recent hop router device participating in the hop-limited downlink source routing; and a step of each second communication device determining, based on the source routing control information, whether to repeat the received source routing information to its member device using the identifier of the second communication device set in the source routing identifier, or to repeat the received source routing information to its member device using the source routing identifier of the received source routing information.

[0022] According to a third aspect, a communication device for a wireless mesh network is provided, the communication device comprising a controller and a wireless radio unit for operating as a wireless node device, the communication device being configured by the wireless radio unit to transmit source routing information to at least one second communication device which is an associated member of the communication device for disseminating at least one function of hop-limited downlink source routing, the source routing information comprising source routing control information and a source routing identifier indicating the latest hop communication device participating in hop-limited downlink source routing.

[0023] According to a fourth aspect, a distribution method for the above-described communication device is provided, the method comprising at least the step of transmitting source routing information by the wireless communication unit of the communication device to at least one second communication device which is an associated member of the communication device for distributing at least one function of hop-limited downlink source routing, wherein the source routing information includes source routing control information and a source routing identifier indicating the latest hop communication device participating in hop-limited downlink source routing.

[0024] According to a fifth aspect, a communication device for a wireless mesh network, the communication device includes a controller and a wireless communication unit for operating as a wireless node device, the communication device receives source routing information from a first communication device, which is a member to which the communication device is related, by the wireless communication unit, the source routing information includes source routing control information and a source routing identifier indicating the latest hop communication device participating in hop-limited downlink source routing, and in response to receiving the source routing information, the controller determines, based on the source routing control information, whether to repeat the received source routing information to the member device using the identifier of the second communication device set in the source routing identifier, or to repeat the received source routing information to the member device using the source routing identifier.

[0025] According to a sixth aspect, a delivery method for the above-described communication device is provided. The method includes a step of receiving, by a wireless communication unit of the communication device, source routing information from a first communication device whose related member is the communication device. The source routing information includes source routing control information and a source routing identifier indicating the latest hop communication device participating in hop-limited downlink source routing. And a step of, in response to the step of receiving the source routing information, determining by a controller of the communication device based on the source routing control information whether to repeat the received source routing information to its member devices using the identifier of the second communication device set in the source routing identifier, or whether to repeat the received source routing information to its member devices using the source routing identifier of the received source routing information. The method includes at least these steps.

[0026] A computer program is provided. The computer program includes instructions that cause a computer to execute at least the steps of the above-described method when the computer program is executed by the computer.

[0027] A tangible non-volatile computer-readable medium is provided. The computer-readable medium includes the above-described computer program.

[0028] Various exemplary and non-limiting embodiments of the present invention regarding both the structure and the operation method will be best understood from the following description of specific exemplary and non-limiting embodiments when read in conjunction with the accompanying drawings, together with its additional objectives and advantages.

[0029] The verbs “to comprise” and “to include” are used herein as open limitations that do not exclude or require the presence of features not recited. Features recited in the dependent claims can be freely combined with each other unless otherwise specified. Further, throughout this specification, it should be understood that the use of “a” or “an,” i.e., the singular, does not exclude the plural.

[0030] Embodiments of the present invention are shown, by way of example and not limitation, in the figures of the accompanying drawings.

Brief Description of the Drawings

[0031] [Figure 1] FIG. is a diagram schematically showing an example of a wireless communication environment in which a delivery system can operate. [Figure 2A] FIG. is a diagram schematically showing an example of a delivery system operating in a wireless mesh network. [Figure 2B] FIG. is a diagram schematically showing an example of a delivery system operating in a wireless mesh network. [Figure 2C] FIG. is a diagram schematically showing an example of a delivery system operating in a wireless mesh network. [Figure 3A] FIG. is a diagram schematically showing an example of a delivery method for delivering source routing information in a wireless communication network by a delivery system. [Figure 3B] FIG. is a diagram schematically showing an example of a decision-making process of a delivery method. [Figure 3C] FIG. is a diagram schematically showing an example of a decision-making process of a delivery method. [Figure 4A] FIG. is a diagram schematically showing an example of delivering source routing information. [Figure 4B] FIG. is a diagram schematically showing an example of delivering source routing information. [Figure 4C] FIG. is a diagram schematically showing an example of delivering source routing information. [Figure 4D] FIG. is a diagram schematically showing an example of delivering source routing information. [Figure 5A] This diagram schematically illustrates an example of distributing source routing information to a wireless mesh network. [Figure 5B] This diagram schematically illustrates another example of distributing source routing information to a wireless mesh network. [Figure 6] This diagram schematically illustrates an example of a decision process for transmitting registration messages in response to changes in associations. [Figure 7] This figure shows another example of a distribution system operating on a wireless mesh network. [Figure 8] This diagram schematically illustrates an example of the routing process for downlink data packets by a distribution system using hop coverage-limited downlink source routing. [Figure 9] This diagram schematically illustrates an example of routing downlink data packets using hop coverage-limited downlink source routing. [Figure 10] This diagram schematically shows an example of the operating part of a wireless communication device. [Modes for carrying out the invention]

[0032] Figure 1 schematically shows an example of a wireless communication environment in which the distribution system 200 may operate. The environment includes a wireless mesh network (system) 102 that includes multiple wireless communication devices (nodes) 104a, 104b, and 104c. Devices 104a, 104b, and 104c operate on the same spectrum, including one or more frequency bands in the same geographical area within the presented environment, for example. Each of the one or more frequency bands may include one or more frequency channels. The use of the same spectrum enables bidirectional wireless communication between devices 104a, 104b, and 104c within the network 102, so that a wireless transmission sent by one device 104a, 104b, or 104c can be received by another device 104a, 104b, or 104c, and vice versa.

[0033] The distribution system 200 can be applied to any wireless communication network 102 that uses packet transmission in communication, i.e., data exchange. Preferably, the system 200 can be applied to any wireless communication network that can be used for multi-hop communication between devices 104a, 104b, and 104c, i.e., packets can be distributed over at least two consecutive wireless links. The system 200 can be applied to a wireless communication network 102 that conforms to the Digital European Cordless Communications (DECT-2020 NR) standard. The DECT-2020 NR standard is a wireless access technology developed by ETSI. Some non-limiting examples to which the routing system 300 can be applied include, but are not limited to, wireless multi-hop networks, wireless mesh networks, e.g., wireless sensor networks (WSN), Bluetooth Low Energy (BLE) mesh networks, Zigbee networks, Thread networks, terrestrial public mobile communication networks (PLMN), wireless local area networks (WLAN), low-power wide area networks (LPWAN), cellular-based local area networks, cellular networks, and / or any other wireless networks. An example of a WSN is described in U.S. Patent No. 8064363.

[0034] As described above, each device 104a, 104b, and 104c can provide bidirectional wireless communication with at least one other device 104a, 104b, and 104c by its wireless communication unit 1036. This means that each device 104a, 104b, and 104c can operate as a transmitter, receiver, or transceiver when it can send at least one message to the other devices 104a, 104b, and 104c and receive at least one message from the other devices 104a, 104b, and 104c in the network 102.

[0035] Network 102 may also include at least one gateway device 105, for example, one, two, three, four, or more gateway devices. Each gateway device 105 acts as a gateway between Network 102 and other external networks 106, such as the Internet, distributing data within and out of Network 102. Each gateway device 105 communicates with at least one sink device (node) 104a, for example, one, two, three, four, or more sink devices, and each sink device 104a acts as a wireless interface to the gateway devices 105 within Network 102. At least one sink device 104a belongs to multiple devices 104a, 104b, 104c in Network 102. Each sink device 104a may be physically connected to the gateway device 105 or may be located separately in different parts of Network 102. If the gateway device 105 includes several sink devices 104a, some may be located connected to the gateway device 105, while others may be located separately in different parts of the network 102.

[0036] The sink device 104a typically has a specific role in routing data packets from network 102 to gateway device 104 and / or from gateway device 104 to network 102. While the sink device's role does not need to be fixed, the sink device 104a may change its role to that of a router, for example, if connectivity to gateway device 105 is lost, or if gateway device 105 is unable to provide services, for example, if gateway device 105 loses connectivity to the internet. Other node devices 104b, 104c can operate in different fixed or non-fixed roles within network 102. Depending on whether the device needs to be involved in data packet forwarding, other devices 104b, 104c in network 102 are either router devices (i.e., routers) 104b, i.e., devices operating in the role of a router, or non-router devices (i.e., non-routers) 104c, i.e., devices operating in the role of a non-router. One method for selecting router and non-router roles can follow the method described, for example, in U.S. Patent No. 10,499,264. The sink device 104a and router device 104b of network 102 can participate in routing operations, i.e., the routing of data packets.

[0037] Each router device 104b maintains connectivity to network 102 and routes (forwards) data (e.g., data packets) from other devices 104a, 104b, and 104c as needed. In other words, each router device 104b is involved in routing data (e.g., data packets within network 102). Each non-router device 104c, like the sink device 104a and router devices 104b, can provide bidirectional communication to send its own data (e.g., data packets) and receive data (e.g., data packets) directed to it, but non-router devices 104c do not route data (e.g., data packets) from other devices 104a, 104b, and 104c. Each device in network 102 may be capable of operating as at least a router 104b or a non-router device 104c. Alternatively, at least some of the devices in the network may operate as router devices 104b or non-router devices 104c, and one or more of the devices in network 102 may operate as router devices 104b only or as non-router devices 104c only.

[0038] Furthermore, each device in network 102 may operate with a limited-capacity battery as either a router device 104b or a non-router device 104c. Both router devices 104b and non-router devices 104c may limit the operation of the wireless communication unit 1036 by having discontinuous transmit / receive modes when the power to the wireless communication unit 1036 is turned off, in order to obtain the maximum operating time. It is preferable that all configuration and registration signaling in network 102 is limited because the battery capacity of router devices 104b and non-router devices 104c is limited. Alternatively, at least some of the devices in network 102 may operate with a limited-capacity battery as either router devices 104b or non-router devices 104c, or one or more of the devices in network 102 may operate with a limited-capacity battery as either a router device 104b or a non-router device 104c only.

[0039] Network 102 includes devices 104b and 104c, and thereafter, all devices 104b and 104c are unable to communicate directly with the sink device 104a, or do not prefer to communicate directly with the sink device 104a, or have a limited radio range, for example, due to the wide distance between devices 104a, 104b, and 104c, interference or signal fading between devices 104a, 104b, and 104c. Accordingly, it is necessary or preferable for devices 104a, 104b, and 104c to use multilink (i.e., multihop) communication between each device 104b, 104c and the sink device 104a.

[0040] Uplink data packets generated by one or more of the multiple communication devices 104b, 104c are routed in the uplink direction within the wireless mesh network 102, i.e., outward from the wireless communication network 102, for example, to one or more external networks 106. Downlink data packets generated by one or more of the multiple communication devices 104a, 104b, 104c are routed in the downlink direction within the wireless mesh network 102, i.e., from one or more external networks 106 into the wireless mesh network 102.

[0041] Figures 2A to 2C schematically illustrate an example of a distribution system 200 operating in a wireless mesh network 102. The distribution system 200 is used to distribute, i.e., deliver, source routing information to the wireless network 102. The source routing information represents at least one function of hop-limited downlink source routing. Hop-limited downlink source routing-based routing solutions are used to route downlink data (e.g., at least one downlink data packet) from a source device (e.g., sink device 104a) to a limited number of (wireless) hops, after which the downlink data is routed to a destination device using at least one other routing solution, e.g., a routing table-based routing solution and / or a downlink flooding-based routing solution. In a hop-limited downlink source routing-based routing solution, the downlink data packet includes a destination device identifier (destination device ID) and source routing path data representing the communication path from the source device to the last device participating in the hop-limited downlink source routing. Source routing information is distributed to network 102 to inform communication devices on network 102 that a hop-limited downlink source routing-based routing solution is being used and to inform them of at least one function of the hop-limited downlink source routing-based routing solution. Hop-limited downlink source routing is described later in this application.

[0042] In the examples of Figures 2A to 2C, the wireless mesh network 102 is implemented in a cluster tree topology. However, the distribution solutions described herein are not limited to this, and the wireless mesh network 102 may be implemented in other mesh topologies besides the cluster tree topology. The distribution system 200 includes a first communication device 202 and one or more second communication devices 204a to 204n that are associated members of the first communication device 202. The first communication device 202 and one or more second communication devices 204a to 204n belong to a plurality of communication devices of the wireless mesh network 102. One or more second communication devices 204a to 204n are associated with the first communication device 202 to operate as member devices of the first communication device 202. After association, the first communication device 202 knows, or recognizes, the member device identifier (ID), i.e., the member device identifier (member device ID). The first communication device 202 is the parent device of one or more second communication devices 204a to 204n. The first communication device 202 may be a sink device 104a or a router device 104b. One or more second communication devices 204a to 204n may be a router device 104b and / or a non-router device 104c. Each second communication device 204a, 204c to 204n that is a router device 104b may further include at least one member device 206a to 206n. At least one member device 206a to 206n of each second communication device 204a to 204n belongs to a plurality of communication devices of the wireless mesh network 102. The system 200 may further include a plurality of other wireless communication devices that belong to a plurality of communication devices of the wireless mesh network 102. In the example of Figures 2A and 2B, the first communication device 202 is a sink device 104a. In the examples in Figures 2A and 2B, one or more second communication devices 204a to 204n include one non-router device 204b and three router devices 204a, 204c to 204n.In the examples of Figures 2A and 2B, each second communication device 204a, 204c-204n, which is the router device 104b, includes at least one member device 206a-206n. In the example of Figure 2C, the first communication device 202 is the router device 104b. In the example of Figure 2C, one or more second communication devices 204a-204n include one non-router device 204b and three router devices 204a, 204c-204n. In the example of Figure 2C, each second communication device 204a, 204c-204n, which is the router device 104b, includes at least one member device 206a-206n.

[0043] Figure 3A schematically shows an example of a distribution method for distributing source routing information within the wireless communication network 102 using the distribution system 200 described above. Figure 3A shows the distribution method as a flowchart.

[0044] In step 310, the first communication device 202 transmits source routing information (SRI) indicating at least one function of hop-limited downlink source routing to at least one of the one or more second communication devices 204a to 204n of the distribution system 200 in order to spread the functionality of at least one function of hop-limited downlink source routing to at least one of the second communication devices 204a to 204n. For example, the source routing information may be a source routing information element (SR IE). The source routing information includes source routing control information and a source routing identifier (source routing ID) indicating the latest hop router device 104b participating in the hop-limited downlink source routing. The source routing control information includes at least a source routing hop limit value. The source routing control information may further include a hop count value. The source routing hop limit value represents the number of hops covered by the hop-limited downlink source routing, i.e., the number of router devices 104b participating in the hop-limited downlink source routing at each branch of the network 102. Each member device of sink device 104a is the first hop communication device of one branch of network 102. That is, network 102 is divided into branches, each having a member device of sink device 104a. In a non-restrictive example, the source routing hop limit may be defined as a 4-bit integer. The hop count value is a parameter for counting the number of hops the source route information has traveled from sink device 104b towards the edge of network 102. The hop count value may be defined as a 4-bit integer, for example, starting from 1 and increasing by 1 for each hop. Generally, the source routing ID is an identifier for router device 104b that performs downlink source routing to communication devices beyond (i.e., below) the router device 104b in that branch of network 102, for example, in a cluster tree topology, i.e., participates in hop-limited downlink source routing.The source routing ID of each router device 104b participating in hop-limited downlink source routing may be unique, or at least locally unique within network 102. In a non-restrictive example, the source routing ID may be a DECT-2020 NR long RD ID. Alternatively, the source routing ID may be any other identifier assigned to router device 104b, for example, during the registration process. The source routing ID included in the source routing information propagated by the first communication device 202 is the identifier of the most recent router device 104b participating in hop-limited downlink source routing on the same branch of network 102 as the first communication device 202. The source routing information may further include a sink device identifier (sink device ID) and / or validity time data. The sink device ID indicates the ID of the sink device 104a in network 102, i.e., the sink device that initially propagated the SRI. The sink device ID may be unique, or at least locally unique within network 102. In a non-limiting example, the sink device ID may be a DECT-2020 NR long RD ID. The validity time data indicates the time period during which a communication device must register with the sink device 104a by transmitting a registration message to the sink device 104a. The time can be expressed, for example, in minutes or hours. The validity time may be counted, for example, from the time the previous registration message was sent to the sink device 104a. Alternatively, the validity time may be counted from the transmission of any other message that the sink device 104a may use to detect the location of the communication device in the network 102. The registration of the communication device is described later in this application. The source routing ID, source routing control information, sink device ID, and / or validity time data included in the source routing information may represent at least one function of hop-limited downlink source routing.The expression “communication device identifier (ID)” throughout this application means an identifier that identifies the communication device. For example, the identifier may include the address of the communication device (e.g., a short address or a long address), a value unique to the communication device, or any other identifier that identifies the communication device.

[0045] The source routing hop limit may be defined by the sink device 104a or one or more management entities (i.e., backend entities) of the external network 106. The management entity may be any computing entity, such as a cloud server. The source routing hop limit defines how deep hop-limited downlink source routing goes at each branch of network 102. Alternatively, or in addition to this, the sink device 104a or the management entity may define the depth of hop-limited downlink source routing at each branch of network 102 based on physical location, traffic load (i.e., the number of data packets received and transmitted), and / or at least one previously received registration message. Physical location may be determined, for example, as geographical or relative coordinates, a range of coordinates, an identifier of a known area or known location, or an estimated distance to a known location.

[0046] If the first communication device 202 is a sink device 104a, the first communication device 202 may transmit source routing information by broadcasting a beacon message containing source routing information to all of the second communication devices 204a to 204n of one or more second communication devices 204a to 204n. In other words, if the first communication device 202 is a sink device 104a, it broadcasts source routing information to all of its member devices, i.e., all second communication devices 204a to 204n that are associated members of the sink device 104a. This is illustrated in the example in Figure 2A, where the first communication device 202a, which is the sink device 104a, broadcasts source routing information to all of the member devices of the sink device 104a, i.e., all of the second communication devices 204a to 204n. Source routing information can be distributed to all branches of the network 102 at once by transmitting it from the sink device 104a to all of its member devices by broadcasting source information.

[0047] If the first communication device 202 is a sink device 104a, the first communication device 202 may, alternatively, transmit source routing information by unicasting a control message containing source routing information to at least one of the one or more second communication devices 204a to 204n. In other words, if the first communication device 202 is a sink device 104a, it unicasts source routing information to at least one of its member devices, i.e., at least one second communication device 204a to 204n that is an associated member of the sink device 104a. This is illustrated in the example in Figure 2B, where the first communication device 202a, which is the sink device 104a, broadcasts source routing information to one of the member devices of the sink device 104a, i.e., one second communication device 204a. The process of transmitting source information from a sink device 104a by unicasting to only a limited number of member devices of the sink device 104a, wherein the limited number is at least one, allows for branch-limited distribution of source routing information. For example, the sink device 104a may first transmit source routing information to at least one member device of the sink device 104a, and then the sink device 104a may transmit source routing information to at least one other member device (other than the at least one member device to which the source routing information was first transmitted). This branch-limited distribution of source routing information may continue until the source routing information has been transmitted to all member devices of the sink device 104a. Branch-limited distribution of source routing information allows the sink device 104a to control the reception of registration messages. For example, it may control the total number of registration messages that the sink device 104a receives. In another example, it may control the number of registration messages that the sink device 104a receives substantially simultaneously. Registration messages are described later in this application.

[0048] Alternatively, or in addition to the above, if the first communication device 202 is a router device 104b, the first communication device 202 may transmit the source routing information to all second communication devices 204a-204n by broadcasting a beacon message containing the source routing information. In other words, if the first communication device 202 is a router device 104b, it broadcasts the source routing information to all of its member devices, i.e., all second communication devices 204a-204n that are associated members of router device 104b. This is illustrated in the example in Figure 2C, where the first communication device 202a, which is router device 104b, broadcasts the source routing information to all of the member devices of router device 104b, i.e., all second communication devices 204a-204n. Alternatively, if the first communication device 202 is a router device 104b, the first communication device 202 may transmit source routing information to all second communication devices 204a to 204n by unicasting a control message containing source routing information.

[0049] If the first communication device 202 is a sink device 104a, the first communication device 202 may transmit source routing information at least once. For example, if network 102 is a closed network, it may be sufficient to transmit source routing information only once, but preferably, the source routing information may be transmitted more than once by the first communication device 202. Alternatively, if the first communication device is a sink device 104a, the first communication device 202 may transmit source routing information periodically, for example, at regular intervals and / or irregular intervals. In a non-limiting example, source routing information may be included in each beacon message broadcast by the sink device 104a. If the first communication device 202 is a router device 104b, the first communication device 202 transmits source routing information in response to receiving source routing information from its parent device.

[0050] In step 320, at least one second communication device 204a to 204n receives source routing information from the first communication device 202. In the examples of Figures 2A and 2C, all second communication devices 204a to 204n receive source routing information from the first communication device 202. In the example of Figure 2B, i.e., branch-only distribution, only the second communication device 204a receives source routing information from the first communication device 202.

[0051] In step 330, in response to receiving source routing information from the first communication device 202 in step 320, each second communication device 204a to 204n, which is a router device 104b, determines, based on the source routing control information contained in the source routing information, whether to repeat the received source routing information to its member devices 206a to 206n using the identifiers of the second communication devices 204a to 204n set in the source routing identifiers, or to repeat the information to its member devices 206a to 206n using the source routing identifiers of the received source routing information. If the second communication devices 204a to 204n determine, based on source routing control information, that the first communication device 202 is not the last router device 104b on this branch of network 102 participating in hop-limited downlink source routing, the second communication devices 204a to 204n decide to repeat the received source routing information to their member devices 206a to 206n using the identifiers of the second communication devices 204a to 204n set in the source routing identifier. Alternatively, if the second communication devices 204a to 204n determine, based on source routing control information, that the first communication device 202 is the last router device 104b on this branch of network 102 participating in hop-limited downlink source routing, the second communication devices 204a to 204n decide to repeat the received source routing information to their member devices 206a to 206n using the source routing identifier of the received source routing information.

[0052] The decision in step 330 based on source routing control information contained in source routing information depends on the content of the control information. Figures 3B and 3C schematically illustrate an example of decision-making in step 330. In the example of Figures 3B and 3C, the decision is made directly based on source routing control information contained in the received source routing information. However, the decision may also be made based on source routing control information set by at least one second communication device 204a-204n, which is router device 104b, based on source routing control information contained in the received source routing information. In this case, the conditions for decision-making and / or the values ​​of the source routing control information may differ from the conditions and / or values ​​used in the example of Figures 3B and 3C. Figures 3B and 3C show only non-limiting examples for making a decision in step 330. However, the same decision result may be achieved by one or more other decision-making methods. In other words, the decision-making in step 330 according to this application is not limited to the exemplary method shown in Figures 3B and 3C. According to one or more non-limiting examples of other decision-making methods, the decision may also be based on the physical coordinates of the second communication device 202.

[0053] The example in Figure 3B illustrates an example of a decision-making method for increasing the hop count. In the example in Figure 3B, the source routing control information includes a source routing hop limit and a hop count. When the source routing control information of the source routing information includes a hop count, each communication device receiving the source routing information can define how many hops away the communication device is from the sink device 104a.

[0054] In step 340, in response to receiving source routing information from the first communication device 202 in step 320, each of the second communication devices 204a to 204n, which are router device 104b, compares the hop count value of the received source routing information with the source routing hop limit value of the received source routing information. In other words, each of the second communication devices 204a to 204n, which are router device 104b, that receive source routing information from the first communication device 202, compares the hop count value of the received source routing information with the source routing hop limit value of the received source routing information. In the examples of Figures 2A and 2C, the second communication devices 204a, 204c, and 204n, which are router device 104b, each perform the comparison in response to receiving source routing information from the first communication device 202. In the example of Figure 2B, i.e., branch-only distribution, only the second communication device 204a receives source routing information from the first communication device 202. Since the second communication device 204a is a router device 104b, it performs a comparison in response to receiving source routing information from the first communication device 202.

[0055] In step 350, if the hop count value does not satisfy the source routing hop limit value, at least one second communication device 204a-204n increments the hop count value by 1, sets the ID of the second communication device 204a-204n as the source routing ID, and transmits the received source routing information to its member devices 206a-206n. In the context of a predetermined limit, e.g., a source routing hop limit value, the verb “satisfy” is used in this patent application to mean that a predetermined condition is met. For example, the predetermined condition may be that a predetermined limit has been reached and / or exceeded. The source routing information transmitted by at least one second communication device 204a-204n in step 350 further includes the source routing hop limit value. The source routing information transmitted by at least one second communication device 204a-204n may further include sink device ID and / or validity time data if the sink device ID and / or validity time are included in the source routing information received from the first communication device.

[0056] Figure 4A schematically illustrates an example of disseminating source routing information according to the exemplary decision-making method in Figure 3B. In the example of Figure 4A, the first communication device 202 is a sink device 104a, and the second communication device 204a is a router device 104b, as in the examples of Figures 2A and 2B. The first communication device 202 transmits source routing information to at least the second communication device 204a, for example, by beacon messages or control messages as described above. In the example of Figure 4A, the source routing information includes a source routing ID and source routing control information, which includes a source routing hop limit value and a hop count value. The source routing hop limit value in the source routing information is set to 1. In the source routing information transmitted by the first communication device 202, the hop count value is set to 0. In the source routing information transmitted by the first communication device 202, the ID of the sink device 104a, i.e., the first communication device, is set as the source routing ID. Alternatively, the source routing ID may be left blank in the source routing information transmitted by the first communication device 202, which is the sink device 104a. The second communication device 204a receives the source routing information from the first communication device 202 and performs the comparison described above in step 340. In the example of Figure 4A, the hop count value of the received source routing information is 0 and the source routing hop limit is 1, which means that the result of the comparison in step 340 is that the hop count value does not satisfy the source routing hop limit value. Therefore, the second communication device 204a increases the hop count value by 1, i.e., the hop count value is set to 1, and the ID of the second communication device 204a is set to the source routing ID. Next, the second communication device 204a transmits the received source routing information to its member devices 206a and 206b, the hop count value is 1, and the ID of the second communication device 204a is set to the source routing ID. The source routing information transmitted by the second communication device 204a further includes the source routing hop limit value.

[0057] Alternatively, if the hop count value satisfies the source routing hop limit, at least one second communication device 204a-204n transmits the received source routing information, which includes at least the source routing ID of the received source routing information, to its member devices 206a-206n in step 360. This means that the first communication device 202 is the last router device 104b in this branch of network 102 participating in hop-limited downlink source routing. The source routing information transmitted by at least one second communication device 204a-204n in step 360 may further include the source routing hop limit and a hop count value incremented by 1. Alternatively, or in addition to this, the source routing information transmitted by at least one second communication device 204a-204n in step 360 may further include sink device ID and / or validity time data, if the sink device ID and / or validity time are included in the source routing information received from the first communication device. In response to receiving source routing information including source routing hop limit values ​​and hop count values, each member device 206a-206b, which is router device 104b, performs a comparison as described above in step 340 and transmits the source routing information to its member device according to step 360. Alternatively, in response to receiving source routing information without source routing hop limit values ​​and hop count values, each member device 206a-206n, which is router device 104b, transmits source routing information including the source routing ID of the received source routing information to its member device. Similarly, if a second communication device 204a-204n (or any other communication device) receives source routing information without source routing hop limit values ​​and hop count values, the second communication device 204a-204n (or any other communication device) transmits source routing information including the source routing ID of the received source routing information to its member devices 206a-206n.

[0058] Figure 4B schematically illustrates another example of disseminating source routing information according to the exemplary decision-making method in Figure 3B. In the example of Figure 4B, the first communication device 202 is a router device 104b, and the second communication device 204a is also a router device 104b, as in the example of Figure 2C. The first communication device 202 transmits source routing information to at least the second communication device 204a, for example, in the beacon message described above. In the example of Figure 4B, the source routing information includes a source routing ID and source routing control information, which includes a source routing hop limit value and a hop count value. The source routing hop limit value in the source routing information is set to 2. In the source routing information transmitted by the first communication device 202, the hop count value is set to 2. This means that the first communication device 202 has received source routing information from its parent device, i.e., from a router device to which the first communication device 202 is an associated member. Since the hop count value included in the source information received by the first communication device 202 does not satisfy the source routing hop limit value included in the source information received by the first communication device 202, the ID of the first communication device 202 is set as the source routing ID in the source routing information transmitted by the first communication device 202. The second communication device 204a receives the source routing information from the first communication device 202 and performs the comparison described above in step 340. In the example of Figure 4B, the hop count value of the received source routing information is 2, and the source routing hop limit is 2, which means that the result of the comparison in step 340 is that the hop count value satisfies the source routing hop limit value. This means that the first communication device 202 is the last device in this branch involved in hop-limited downlink source routing. Therefore, the second communication device 204a transmits the received source routing information, which includes at least the source routing ID of the received source routing information, i.e., the ID of the first communication device 202, to its member devices 206a and 206b.The second communication device 204a further increases the hop count value by 1, i.e., sets the hop count value to 3. The source routing information transmitted by the second communication device 204a further includes the source routing hop limit value and the hop count value increased by 1.

[0059] The example in Figure 3C illustrates an example of a decision-making method for reducing source routing hop limits. In the example in Figure 3C, the source routing control information includes the source routing hop limit value.

[0060] In step 370, in response to receiving source routing information from the first communication device 202 in step 320, each second communication device 204a to 204n, which is router device 104b, evaluates the source routing hop limit value included in the source routing control information of the received source routing information. The evaluation of the source routing hop limit value may include defining the value of the source routing hop limit value, i.e., whether the source routing hop limit value is greater than 0.

[0061] In step 380, if the source routing hop limit value included in the received source routing information is greater than 0, at least one second communication device 204a to 204n reduces the source routing hop limit value by 1, sets the identifier of the second communication device 204a to 204n as the source routing identifier, and transmits the received source routing information to its member devices 206a to 206n. The source routing information transmitted by at least one second communication device 204a to 204n may further include sink device ID and / or validity time data if the sink device ID and / or validity time are included in the source routing information received from the first communication device.

[0062] Otherwise, i.e., if the source routing hop limit value included in the received source routing information is 0 or less, at least one second communication device 204a-204n transmits the received source routing information, including at least the source routing identifier of the received source routing information, to its member devices 206a-206n in step 390. This means that the first communication device 202 is the last router device 104b in this branch of network 102 participating in hop-limited downlink source routing. The source routing information transmitted by at least one second communication device 204a-204n in step 390 may further include the source routing hop limit value of the received source routing information. Alternatively, the source routing information transmitted by at least one second communication device 204a-204n in step 390 may further include a source routing hop limit value reduced by 1. However, preferably, in order to avoid negative source routing hop limit values, the source routing hop limit value of the received source routing information, which is 0, is no longer reduced. Alternatively, or in addition to the above, the source routing information transmitted by at least one second communication device 204a-204n in step 390 may further include sink device ID and / or validity time data if the sink device ID and / or validity time are included in the source routing information received from the first communication device. In response to receiving source routing information, which also includes source routing hop limit values, each member device 206a-206b, which is the router device 104b, evaluates the source routing hop limit values ​​included in the source routing control information of the received source routing information, as described above in step 370, and transmits the source routing information to its member device in accordance with step 390.Alternatively, in response to receiving source routing information without a source routing hop limit, each member device 206a-206n, which is router device 104b, transmits source routing information, including the source routing ID of the received source routing information, to its member devices. Similarly, if a second communication device 204a-204n (or any other communication device) receives source routing information without a source routing hop limit, the second communication device 204a-204n (or any other communication device) transmits source routing information, including the source routing ID of the received source routing information, to its member devices 206a-206n.

[0063] Figure 4C schematically illustrates an example of disseminating source routing information according to the exemplary decision-making method in Figure 3C. In the example of Figure 4C, the first communication device 202 is a sink device 104a, and the second communication device 204a is a router device 104b, as in the examples of Figures 2A and 2B. The first communication device 202 transmits source routing information to at least the second communication device 204a, for example, by the beacon message or control message described above. In the example of Figure 4C, the source routing information includes a source routing ID and source routing control information including a source routing hop limit value. The source routing hop limit value of the source routing information transmitted by the first communication device 202 is set to 2. In the source routing information transmitted by the first communication device 202, the ID of the sink device 104a, i.e., the first communication device, is set as the source routing ID. Alternatively, the source routing ID may be left empty in the source routing information transmitted by the first communication device 202, which is the sink device 104a. The second communication device 204a receives source routing information from the first communication device 202 and evaluates the source routing hop limit value included in the source routing control information of the received source routing information. In the example in Figure 4C, the source routing hop limit of the received source routing information is 2, which means that the result of the evaluation in step 370 is that the source routing hop limit value is greater than 0. Therefore, the second communication device 204a reduces the source routing hop limit value by 1, i.e., the source routing hop limit value is set to 1, and the ID of the second communication device 204a is set to the source routing ID. Next, the second communication device 204a transmits the received source routing information to its member devices 206a and 206b, where the source routing hop limit value is 1, and the ID of the second communication device 204a is set to the source routing ID.

[0064] Figure 4D schematically illustrates another example of disseminating source routing information according to the exemplary decision-making method in Figure 3C. In the example of Figure 4D, the first communication device 202 is a router device 104b, and the second communication device 204a is also a router device 104b, as in the example of Figure 2C. The first communication device 202 transmits source routing information to at least the second communication device 204a, for example, in the beacon message described above. In the example of Figure 4D, the source routing information includes a source routing ID and source routing control information, which includes a source routing hop limit value. The source routing hop limit value of the source routing information transmitted by the first communication device 202 is 0. The ID of the first communication device 202 is set as the source routing ID in the source routing information transmitted by the first communication device 202, since the source routing hop limit value included in the source information received by the first communication device 202 is greater than 0. The second communication device 204a receives source routing information from the first communication device 202 and evaluates the source routing hop limit value included in the source routing control information of the received source routing information. In the example in Figure 4D, the source routing hop limit of the source routing information received by the second communication device 204a is 0, which means that the result of the evaluation in step 370 is that the source routing hop limit value is 0. This means that the first communication device 202 is the last device in this branch involved in hop-limited downlink source routing. Therefore, the second communication device 204a transmits the received source routing information, which includes at least the source routing ID of the received source routing information, i.e., the ID of the first communication device 202, to its member devices 206a and 206b. The source routing information transmitted by the second communication device 204a further includes the source routing hop limit value of the received source routing information, i.e., the source routing hop limit value is 0.

[0065] In the above, the distribution of source routing information by the distribution system 200 is described over two consecutive hops. For example, if the first communication device 202 is a sink device 104a, the communication of source routing information from the first communication device 202 to one or more second communication devices 204a to 204n is the first hop communication, and the communication of source routing information from each of the second communication devices 204a to 204b to their member devices 206a to 206n is the second hop communication, as shown, for example, in Figures 2A, 2B, 4A, and 4C. In another example, if the first communication device 202 is a router device 104b, then, as shown in Figures 2C and 4D, for example, the communication of source routing information from the first communication device 202 to one or more second communication devices 204a to 204n is the Nth hop communication, and the communication of source routing information from each second communication device 204a to 204b to its member devices 206a to 206n is the (N+1)th hop communication, where N is at least 2. In the example of Figure 4B, for example, as shown in Figure 4B, the communication of source routing information from the first communication device 202 to the second communication device 204a is the third hop communication, and the communication of source routing information from the second communication device 204a to its member devices 206a to 206n is the fourth hop communication. The distribution of source routing information across two consecutive hops can represent one distribution stage. Distributing source routing information to the network 102 can include one or more distribution stages. Two consecutive distribution stages overlap each other. For example, if the first distribution stage precedes the second distribution stage, the second communication devices 204a to 204n of the first distribution stage are the first communication device 202 of the second distribution stage. This means that the communication of source routing information by the second communication devices 204a to 204n of the first distribution stage corresponds to the communication of source routing information by the first communication device 202 of the second distribution stage.

[0066] Figure 5A schematically illustrates an example of distributing source routing information to network 102. In the example of Figure 5A, the distribution of source routing information includes four distribution stages: a first hop distribution stage, a second hop distribution stage, a third hop distribution stage, and a fourth hop distribution stage. While the distribution of source routing information in the example of Figure 5A includes four distribution stages, the distribution of source routing information to network 102 according to this application is not limited to four distribution stages, and the distribution of source routing information may include any number of distribution stages, at least one. In the example of Figure 5A, the control information for source routing information includes a source routing hop limit value and a hop count value, and the decision in step 330 is performed according to the exemplary increasing hop count decision method shown in Figure 3B. However, the distribution of source routing information to network 102 according to this application is not limited to this, and any other decision method, such as the exemplary decreasing source routing hop limit decision method shown in Figure 3C, may be used.

[0067] In the first hop distribution stage, the sink device 104a is the first communication device 202 of the distribution system 200, and the member devices 502a to 502n of the sink device 104a are one or more second communication devices 204a to 204n of the distribution system 200. In the example in Figure 5A, the member devices 502a to 502n of the sink device 104a are called first hop member devices. In the first hop distribution stage, the sink device 104a transmits source routing information to all first hop member devices 502a to 502n by broadcasting source routing information with the identifier of sink device 104a set as the source routing ID, with the source routing hop limit set to 2, the hop count set to 0, and the source routing ID set to the identifier of sink device 104a. In response to receiving source routing information from the sink device 104a, each of the first hop member devices 502a, 502c-502n, which is the router device 104b, transmits the source routing information to its member devices 504a-504n by incrementing the hop count to 1 (i.e., the hop count increases to 1), and sets the identifiers of the first hop member devices 502a, 502c-502n as the source routing ID. In the example in Figure 5A, the member devices 504a-504n of the first hop member devices 502a-502n are called second hop member devices.

[0068] In the second hop distribution stage, each of the first hop member devices 502a, 502c-502n, which are router device 104b, is the first communication device of the distribution system 200, and the second hop member devices 504a-504n of the first hop member devices 502a, 502c-502n are the second communication devices 204a-204n of the distribution system 200. In the second hop distribution stage, in response to receiving source routing information from each of the first hop member devices 502a, 502c-502n, each of the second hop member devices 504a, 504c-504n, which are router device 104b, transmits source routing information to its member devices 506a-506n, in which the hop count is increased by 1 (i.e., the hop count increases to 2) and the identifier of the second hop member device 504a, 504c-504n is set as the source routing ID. In the example in Figure 5A, member devices 506a to 506n of the second hop member devices 504a to 504n are called the third hop member devices.

[0069] In the third hop distribution stage, each of the second hop member devices 504a, 504c-504n, which is router device 104b, is the first communication device 202 of the distribution system 200, and the third hop member devices 506a-506n of the second hop member devices 504a, 504c-504n are the second communication devices 204a-204n of the distribution system 200. In the third hop distribution stage, in response to receiving source routing information from each of the second hop member devices 504a, 504c-504n, each of the third hop member devices 506b, 506c, 506e, which is router device 104b, transmits source routing information including at least the source routing ID of the identifier of the received source information. This means that the second hop member devices 504a, 504c-504n, which is router device 104b, are the last devices in their branches of network 102 participating in hop-limited downlink source routing. Devices involved in hop-limited downlink source routing are indicated by the dashed area 500. In the example in Figure 5A, member devices 508a to 508n of the third hop member devices 506a to 506n are referred to as the fourth hop member devices.

[0070] In the fourth hop distribution stage, each of the third hop member devices 506b, 506c, and 506e, which are router devices 104b, are the first communication devices 202 of the distribution system 200, and the fourth hop member devices 508a to 508n of the third hop member devices 506b, 506c, and 506e are the second communication devices 204a to 204n of the distribution system 200. Since all of the fourth hop member devices 508a to 508n, i.e., all of the second communication devices, are non-router devices 104c that do not have member devices, in the fourth hop distribution stage, the source routing information reaches all devices in the network 102.

[0071] Figure 5B schematically illustrates another example of disseminating source routing information to network 102. The example in Figure 5B corresponds to the example in Figure 5A above, but in the example in Figure 5B, branch-only distribution is used. Distribution is limited to branches where member devices 502a and 502c of the first hop are member devices of sink device 104a.

[0072] Each communication device transmits a registration message to the sink device 104a when it is associated with network 102. The registration message may include at least a source routing ID included in the source routing information received by the communication device. The registration message may further include, for example, the parent device identifier (parent device ID) of the communication device. The parent device ID indicates the parent device to which the communication device is associated. Alternatively, or in addition to this, the registration message may further include a sink device ID. The sink device ID included in the registration message ensures that the registration message is received by the correct sink device. The sink device 104a may store the content of the received registration message, for example, in the memory unit 1034 of the sink device 104a. Alternatively, or in addition to this, the sink device 104a may store the content of the received registration message in a memory unit of one or more management entities of the external network 106, for example, a database, or transmit the content of the received registration message to be stored in a memory unit of one or more management entities of the external network 106, for example, a database. The contents of the registration message may be delivered to the management entity via the gateway device 105. Based on the received registration message, the sink device 104a and / or the management entity form source routing paths to each source routing ID and then list the communication devices beyond each formed source routing path. Propagating the registration message to the sink device 104a allows the sink device 104a and / or the management entity to continue tracking the communication devices associated with the wireless mesh network 102 and the location of each communication device in the network. Member devices of the sink device 104a do not necessarily need to propagate the registration message to the sink device 104a because the association message propagated during the association procedure already contains the information contained in the registration message.

[0073] At least one of the one or more second communication devices 204a to 204n of the distribution system 200, namely a second communication device 204a, can change its association from the first communication device 202 to a third communication device 702. The third communication device 702 belongs to a group of communication devices in the wireless mesh network 102. Each of the second communication devices 204a to 204n that has changed its association can transmit a registration message if the existing registration is no longer valid after the changed association. Figure 6 schematically shows an example of a decision process for transmitting a registration message in response to the association change by the distribution system 200 described above. Figure 6 shows the decision process as a flowchart. The decision process is mainly explained using the distribution system 200, which includes the first communication device 202, one of the second communication devices 204a, and the third communication device 702. The distribution system 200 may further include at least one other second communication device 204b-204n, for example, one, two, three, four, or more other second communication devices. The decision process has been described using the distribution system 200 which includes one second communication device 204a, but each second communication device 204a-204n of the distribution system 200 can independently perform steps (i.e., features) of the decision process, as described for one second communication device 204a. In the example of Figure 6, the first communication device 202 is the router device 104b. If a member device of the sink device 104a changes its association with another device, it is no longer a member of the sink device 104a, and therefore does not need to send a registration message to the sink device 104a.

[0074] In step 610, the second communication device 204a changes its association from the first communication device 202 to the third communication device 702. The change in association from the first communication device 202 to the third communication device 702 means that before the association change, the first communication device 202 was the parent device of the second communication device 204a, and after the association change, the third device is the parent device of the second communication device 204a. Before the association change, the second communication device 204a receives source routing information from the first communication device 202, as described above in relation to the distribution of source routing information. After the association change, the second communication device 204a receives source routing information from the third communication device 702, in the same manner as described above in relation to the distribution of source routing information.

[0075] In step 620, in response to a change in association from the first communication device 202 to the third communication device 702, the second communication device 204a may compare the source routing ID contained in the source routing information received from the third communication device 702 with the source routing ID contained in the source routing information received from the first communication device 202. If the source routing ID contained in the source routing information received from the first communication device 202 corresponds to the source routing ID contained in the source routing information received from the third communication device 702, it means that the first and third communication devices are on the same source routing path, which means that the existing registration of the second communication device 204 is valid and there is no need to transmit a new registration message to the sink device 104a. If the source routing ID contained in the source routing information received from the first communication device 202 is different from the source routing ID contained in the source routing information received from the third communication device 702, it means that the first and third communication devices are on the same source routing path but differently.

[0076] In step 630, if the source routing ID included in the source information received from the third communication device 702 differs from the source routing ID included in the source routing information of the first communication device 202, the second communication device 204a sends a registration message to the third communication device 702 in order to route the registration message to the sink device 104a. The registration message includes at least the source routing ID included in the source routing information received from the third communication device 702. The registration message is routed to the sink device 104a using multi-hop communication via one or more router devices 104b in the multi-hop communication path between the third communication device 702 and the sink device 104a. Figure 7 shows an example of the distribution system 200, in which the second communication device 204a changes its association from the first communication device 202 to the third communication device 702. The second communication device 204a receives source routing information from the first communication device before changing its association as described above in relation to the distribution of source routing information. The second communication device 204a receives source routing information from the third communication device 702 after changing the association, similar to how the distribution of source routing information is described above. In the example in Figure 7, the source routing ID included in the source information received from the first communication device 202 is different from the source routing ID included in the source routing information of the third communication device 702. Therefore, the second communication device 204a sends a registration message (RM) to the third communication device 702 in order to route the registration message to the sink device 104a. In the example in Figure 7, the registration message is routed to the sink device 104a using multi-hop communication via one router device 104b, but the multi-hop communication path between the third communication device 702 and the sink device 104a can also include multiple router devices 104b.

[0077] Alternatively, if the source routing ID included in the source information received from the first communication device 202 corresponds to the source routing ID included in the source routing information of the third communication device 702, the second communication device 204a may define in step 640 that the existing registration is valid. If the existing registration is defined as valid, the second communication device 204a does not send a registration message to the sink device 104a. Since a registration message is sent to the sink device 104a by the communication device only when the existing registration is not valid, the number of registration messages received by the sink device 104a is reduced. This means that the transmission of unnecessary registration messages (i.e., registration messages transmitted when the existing registration is still valid) can be avoided.

[0078] Alternatively or additionally, if the routing information includes validity period data, each second communication device 204a-204n may send a registration message to the first communication device 202 to route the registration message to the sink device 104a according to the validity period data, but the second communication devices 204a-204n do not change their association. The registration message includes at least the source routing ID contained in the source routing information received from the first communication device 202. For example, the validity period data may indicate that the registration is valid for a specific time, e.g., 12 or 24 hours, and each second communication device 204a-204n may send a registration message to the first communication device 202 to route the registration message to the sink device 104a after the expiration of the specific time. Alternatively, the validity period data may indicate that registration must be performed once within a specific period, for example, once a day, and each second communication device 204a to 204n may send a registration message to the first communication device 202 once within a specific period to route the registration message to the sink device 104a.

[0079] After distributing source routing information to network 102, downlink data packets can be routed from sink device 104a to one or more destination devices 902 within network 102 using hop-limited downlink source routing. Figure 8 schematically illustrates an example of the routing process for downlink data packets by distribution system 200 using hop-limited downlink source routing. Figure 8 shows the routing process as a flowchart.

[0080] In step 810, the second communication device 204a receives a downlink data packet from the first communication device 202 containing a destination device ID and source routing path data. As described above, the source routing path data represents the communication path from the source device, i.e., the device sending the downlink data packet (e.g., sink device 104a), to the last device involved in the hop-limited downlink source routing. The source routing path data may include, for example, the ID of the device involved in the hop-limited downlink source routing.

[0081] In step 820, in response to receiving a downlink data packet from the first communication device 202, the second communication device 204a may define whether the source routing path data includes an identifier of a member device 206a of the second communication device 204a, i.e., the member device identifier (member device ID) of the second communication device 204a. If the IDs of member devices 206a to 206n of the second communication device 204a are included in the hop route data, it means that the member device 206a is involved in hop-limited downlink source routing.

[0082] In step 830, if the source routing path data includes the ID of member device 206a of the second communication device 202 in step 820, the second communication device 204a unicasts the downlink data packet to the member device 206a. Since the source routing path data indicates that only member device 206a of the second communication device 204a participates in hop-limited downlink source routing, there is no need to propagate the downlink data packet to the other member devices 206b-206n of the second communication device 204b.

[0083] Alternatively, or in addition to the above, in step 840, in response to receiving a downlink data packet from the first communication device 202, the second communication device 204a may define whether the destination device ID included in the downlink data packet corresponds to the ID of a member device 206a of the second communication device 204a, i.e., the member device ID of the second communication device 204a. If the destination device ID corresponds to the ID of a member device 206a of the second communication device 204a, it means that the member device 206a of the second communication device 204a is the destination device 902.

[0084] In step 850, if the destination device ID corresponds to the ID of member device 206a of the second communication device 204a in step 840, the second communication device 204a unicasts a downlink data packet to the member device 206a.

[0085] Otherwise, in step 860, the second communication device 204a sends the downlink data packet to all of its router member devices, for example, by unicast, in order to route the downlink data packet to the destination device 902. The downlink data packet may be routed to the destination device 902 using at least one other routing solution. At least one other routing solution may include one or more known routing solutions, for example, a routing table-based routing solution and / or a downlink flooding-based routing solution.

[0086] The routing of downlink data packets by the distribution system 200 is described over two consecutive hops. For example, if the first communication device 202 is a sink device 104a, then the downlink data packet from the first communication device 202 to the second communication device 204a is the first hop communication, and the downlink data packet communication from the second communication device 204 to its member devices is the second hop communication. In another example, if the first communication device 202 is a router device 104b, then the downlink data packet communication from the first communication device 202 to the second communication device 204a is the Nth hop communication, and the downlink data packet communication from the second communication device 204a to its member devices is the (N+1)th hop communication. The routing of downlink data packets over two consecutive hops can represent one routing stage. Routing downlink data packets from a source device to a destination device 902 may involve one or more routing stages. Two consecutive routing stages overlap each other. For example, if the first routing stage precedes the second routing stage, the second communication device 204 of the first routing stage is the first communication device 202 of the second routing stage, which means that the communication of downlink data packets by the second communication device 204a of the first routing stage corresponds to the communication of downlink data packets by the first communication device 202 of the second routing stage.

[0087] Figure 9 schematically illustrates an example of routing a downlink data packet (DP) from sink device 104a to destination device 902 using hop-limited downlink source routing. The downlink data packet includes the destination device ID and source routing path data. In the example in Figure 9, the communication path from sink device 104a to the last device involved in hop-limited downlink source routing includes sink device 104a, first-hop member device 502a, and second-hop member device 504a. Therefore, the source routing path data in the example in Figure 9 includes the ID of sink device 104a, the ID of first-hop member device 502a, and the ID of second-hop member device 504a. Thus, in the example in Figure 9, hop-limited downlink source routing is used until the downlink data packet is routed to second-hop member device 504a, after which the downlink data packet is routed using a downlink flooding-based routing solution. In the example in Figure 9, the routing of the downlink data packet involves four routing stages: a first-hop routing stage, a second-hop routing stage, a third-hop routing stage, and a fourth-hop routing stage. Although the routing of the downlink data packet in the example in Figure 9 involves four routing stages, the routing of downlink data packets using hop-limited downlink source routing as described herein is not limited to four routing stages, and the routing of the downlink data packet may include any other number of routing stages, as long as there is at least one.

[0088] In the first hop routing stage, the sink device 104a is the first communication device 202 of the distribution system 200, and the first hop member device 502a is the second communication device 204a of the distribution system 200. In the first hop routing stage, the sink device 104a unicasts a downlink data packet to the first hop member device 502a. In response to receiving the downlink data packet from the sink device 104a, the first hop member device 502a unicasts the downlink data packet to the second hop member device 504a, since the source routing path data includes the ID of the second hop member device 904a.

[0089] In the second hop routing stage, the first hop member device 502a is the first communication device 202 of the distribution system 200, and the second hop member device 504a is the second communication device of the distribution system 200. In the second hop routing stage, the second hop member device 504a receives a downlink data packet from the first hop member device 502a. In response to receiving the downlink data packet from the first hop member device 502a, the second hop member device 504a sends the downlink data packet to all of its router member devices 506a and 506b in order to flood the downlink data packet so that it reaches the destination device 902, because the source routing data does not include the IDs of the second hop member device 504a's member devices 506a and 506b, and the destination device ID included in the downlink data packet does not correspond to the IDs of the second hop member device 504a's member devices 506a and 506b.

[0090] In the third and fourth hop routing stages, downlink data packets are flooded so that they reach the destination device 902.

[0091] Figure 10 schematically shows communication devices 104a-104c, 202, 204a-204n, and 206a-206n that can communicate within the network 102 and perform the relevant features (processes) of the distribution method as described above. In other words, a device that operates as the first communication device 202 and can perform the features of the distribution method associated with the first communication device 202 has been described, and / or a device that operates as the second communication devices 204a-204n and can perform the features of the distribution method associated with the second communication devices 204a-204n has been described, and / or a device that operates as member devices 206a-206n and can perform the features of the distribution method associated with member devices 206a-206n has been described.

[0092] Devices 104a-104c, 202, 204a-204n, and 206a-206n include a controller (control unit) 1030 that controls the operation of parts 1032, 1034, 1036, 1038, and 1040 of devices 104a-104c, 202, 204a-204n, and 206a-206n so that they operate as described above.

[0093] The controller 1030 includes a processor (processor unit) 1032 that executes operator start instructions and / or computer program start instructions and processes data to run the application. The processor 1032 may include at least one processor, for example, one, two, three, four, or more processors.

[0094] The controller 1030 also includes a memory (memory section) 1034 for storing and maintaining data. The data may be instructions, computer programs, and data files. The memory 1034 includes at least one memory, for example, one, two, three, four, or more memory units.

[0095] Devices 104a-104c, 202, 204a-204n, and 206a-206n also include a radio communication unit (radio communication unit, data transfer unit) 1036 and an antenna 1038 (antenna unit) used by the controller 1030 to transmit commands, requests, messages (e.g., request messages), and data (e.g., source routing information and / or downlink data packets) via the antenna 1038 to at least one of the devices in the distribution system 200 and / or network 102. The radio communication unit 1036 also receives commands, requests, and data (e.g., source routing information and / or data packets) from at least one of the devices in the distribution system 200 and / or network 102 via the antenna 1038. Communication between the wireless communication unit 1036 of devices 104a-104c, 202, 204a-204n, and 206a-206n and other devices in the distribution system 200 and / or network 102 is provided wirelessly via antenna 1038.

[0096] Devices 104a-104c, 202, 204a-204n, and 206a-206n may further include a power supply unit 1040. The power supply unit 1040 includes components for supplying power to devices 104a-104c, 202, 204a-204n, and 206a-206n, such as a battery and a regulator.

[0097] Memory 1034 stores at least a wireless communication (RC) application 1042 for operating (controlling) the wireless communication unit 1036 and a power supply (PS) application 1044 for operating the power supply unit 1040.

[0098] Memory 1034 also stores computer programs (CPs) (i.e., computer software, computer applications) 1046 which, when executed by the computer, for example, devices 104a-104c, 202, 204a-204n, 206a-206n, by the controller 1030, use at least one of parts 1036, 1038, and 1040 to perform the operations of at least the devices 104a-104c, 202, 204a-204n, 206a-206n as described above.

[0099] The computer program 1046 can be stored on a tangible, non-volatile, computer-readable storage medium, such as a compact disc (CD) or a Universal Serial Bus (USB) type storage device.

[0100] The distribution system 200 and distribution method described above enable a balance between a source routing-based routing solution and at least one other routing solution in routing downlink data packets within network 102. At least some embodiments of the distribution system 200 and distribution method described above can reduce the volume of registration messages by limiting the number of hops for downlink source routing by using source routing only up to a selected number of hops, and / or by gradually applying the hop-limited downlink source routing to different branches of network 102. Alternatively, or in addition to this, at least some embodiments of the distribution system 200 and distribution method described above enable control over the number of IDs included in the source routing path data included in each downlink data packet, and thus control the overhead introduced into the downlink data packets. Alternatively, or in addition to this, at least some embodiments of the distribution system 200 and distribution method described above enable control over the sink device 104a receiving registration messages from different branches of network 102 at the same depth. Alternatively, or in addition to the above, at least some aspects of the distribution system 200 and distribution method described above do not require the maintenance of routing tables, thus enabling the avoidance of significant memory consumption from router devices 104b close to sink device 104a (i.e., router devices 104b participating in hop-limited downlink source routing), but the amount of downlink flooding may also be limited.

[0101] The specific examples provided in the above description should not be construed as limiting the applicability and / or interpretation of the attached claims. The list and group of examples provided in the above description are not exhaustive unless otherwise specified.

Claims

1. A distribution system (200) for a wireless mesh network (102) including multiple communication devices (104a to 104c), wherein the distribution system (200) is The first communication device (202) and The first communication device (202) includes one or more second communication devices (204a to 204n) which are associated members of the first communication device (202), The first communication device (202) and the one or more second communication devices (204a to 204n) belong to the plurality of communication devices (104a to 104c) of the wireless mesh network (102), The first communication device (202) is configured to transmit source routing information to at least one of the one or more second communication devices (204a to 204n) in order to deliver at least one function of hop-limited downlink source routing, wherein the source routing information includes source routing control information and a source routing identifier indicating the most recent hop router device (104b) participating in the hop-limited downlink source routing. A distribution system (200) is configured such that, in response to receiving source routing information from the first communication device (202), each second communication device (204a to 204n), which is a router device (104b), determines, based on the source routing control information, whether to repeat the received source routing information to its member devices (206a to 206n) using the identifier of the second communication device (204a to 204n) set as the source routing identifier, or to repeat the received source routing information to its member devices (206a to 206n) using the source routing identifier of the received source routing information.

2. The first communication device (202) is, By broadcasting the beacon message containing the source routing information to all second communication devices (204a to 204n), or The system (200) according to claim 1, wherein the sink device (104a) is configured to transmit the source routing information by unicasting a control message containing the source routing information to at least one second communication device (204a) among the one or more second communication devices (204a to 204n).

3. The system (200) according to claim 1, wherein the first communication device (202) is a router device (104b) configured to transmit the source routing information to the at least one second communication device (204a to 204n) by broadcasting a beacon message containing the source routing information or by unicasting a control message containing the source routing information.

4. The source routing control information includes a source routing hop limit value and a hop count value representing the number of hops covered by the hop-limited downlink source routing, and in response to receiving the source routing information from the first communication device (202), each second communication device (204a to 204n), which is a router device (104b), The hop count value of the received source routing information is compared with the source routing hop limit value of the received source routing information, When the hop count value increases by 1, and the identifier of the second communication device (204a to 204n) is set to the source routing identifier, and the hop count value does not satisfy the source routing hop limit, the received source routing information is transmitted to its member device (206a to 206n), or The system (200) according to any one of claims 1 to 3, configured to transmit the received source routing information, including at least the source routing identifier of the received source routing information, to its member devices (206a to 206n) when the hop count value satisfies the source routing hop limit value.

5. The source routing control information of the source routing information includes a source routing hop limit value representing the number of hops covered by the hop-limited downlink source routing, and in response to receiving the source routing information from the first communication device (202), each second communication device (204a to 204n), which is a router device (104b), If the source routing hop limit value of the received source routing information is greater than 0, the received source routing information is transmitted to its member devices (206a to 206n) using the source routing hop limit value reduced by 1 and the identifier of the second communication device (204a to 204n) set in the source routing identifier, or Otherwise, the system (200) according to any one of claims 1 to 3 is configured to transmit the received source routing information, including at least the source routing identifier of the received source routing information, to its member devices (206a to 206n).

6. When each second communication device (204a to 204n) changes its association from the first communication device (202) to a third communication device (702) belonging to the plurality of communication devices (104a to 104n) of the wireless mesh network (102), the second communication devices (204a to 204n) The source routing identifier included in the source routing information received from the third communication device (702) is compared with the source routing identifier included in the source routing information received from the first communication device (202), If the source routing identifier included in the source information received from the first communication device (202) is different from the source routing identifier included in the source routing information of the third communication device (702), the registration message is sent to the third communication device (702) in order to route the registration message to the sink device (104a), or A system (200) according to any one of claims 1 to 5, configured to define an existing registration as valid if the source routing identifier included in the source information received from the first communication device (202) corresponds to the source routing identifier included in the source routing information of the third communication device (702).

7. The system (200) according to any one of claims 1 to 6, wherein the source routing information further includes validity time data, and each second communication device (204a to 204n) is configured to send the registration message to the first communication device (202) in order to route the registration message to the sink device (104a) according to the validity time data.

8. In response to receiving the downlink data packet, which includes source routing path data and an identifier for the destination device (902) of the downlink data packet, from the first communication device (202), each of the second communication devices (204a to 204n) performs the following actions: If the source routing path data includes the identifier of a member device (206a to 206n) of the second communication device (204a to 204n), the downlink data packet is unicast to the member device (206a to 206n), or If the identifier of the destination device (902) corresponds to the identifier of a member device (206a to 206n) of the second communication device (204a to 204n), the downlink data packet is unicast to the member device (206a to 206n), or Otherwise, the system (200) according to any one of claims 1 to 7 is configured to transmit the downlink data packet to all of its router member devices in order to route the downlink data packet to the destination device (902).

9. The system (200) according to any one of claims 1 to 6, wherein the first communication device (202) is configured to periodically transmit the source routing information.

10. A distribution method for a wireless mesh network (102), wherein the distribution method comprises at least, A step (310) of a first communication device (202) transmitting source routing information to at least one second communication device (204a-204n) which is an associated member of the first communication device (202) for distributing at least one function of hop-limited downlink source routing, wherein the source routing information includes source routing control information and a source routing identifier indicating the most recent hop router device (104b) participating in the hop-limited downlink source routing. A distribution method comprising: a step (330) in which, in response to a step (320) of receiving source routing information from a first communication device (202), each second communication device (204a to 204n) determines, based on source routing control information, whether to repeat the received source routing information to its member devices (206a to 206n) using the identifier of the second communication device (204a to 204n) set in the source routing identifier, or to repeat the received source routing information to its member devices (206a to 206n) using the source routing identifier of the received source routing information.

11. A communication device (202) for a wireless mesh network (102), wherein the communication device (202) is Controller (1030), It includes a wireless communication unit (1036) for operating as a wireless node device, The aforementioned communication device (202) The wireless communication unit (1036) is configured to transmit source routing information to at least one second communication device (204a-204n) which is an associated member of the communication device (202) for disseminating at least one function of source routing of a hop-limited downlink, wherein the source routing information includes source routing control information and a source routing identifier indicating the most recent hop router device (104b) participating in the source routing of the hop-limited downlink.

12. A distribution method for a communication device (202) according to claim 11, wherein the distribution method comprises at least, A distribution method comprising the step (310) of transmitting source routing information by the wireless communication unit (1036) of the communication device (202) to at least one second communication device (204a to 204n) which is an associated member of the communication device (202) for distributing at least one function of hop-limited downlink source routing, wherein the source routing information includes source routing control information and a source routing identifier indicating the latest hop router device (104b) participating in the hop-limited downlink source routing.

13. A communication device (204a to 204n) for a wireless mesh network (102), wherein the communication device (204a to 204n) is Controller (1030), It includes a wireless communication unit (1036) for operating as a wireless node device, The aforementioned communication devices (204a to 204n) The wireless communication unit (1036) receives source routing information from a first communication device (202) in which the communication devices (204a to 204n) are associated members, and the source routing information includes source routing control information and a source routing identifier indicating the latest hop router device (104b) participating in hop-limited downlink source routing. Communication devices (204a to 204n) are configured such that the wireless communication unit (1036) determines, based on the source routing control information, whether to repeat the received source routing information to its member devices (206a to 206n) using the identifier of the communication device (204a to 204n) set in the source routing identifier, or to repeat the received source routing information to its member devices (206a to 206n) using the source routing identifier of the received source routing information, and the controller (1030) determines this.

14. A distribution method for a communication device (204a to 204n) according to claim 13, wherein the distribution method comprises at least: A step (320) of the communication devices (204a to 204n) receiving source routing information from a first communication device (202) which is a related member, wherein the source routing information includes source routing control information and a source routing identifier indicating the latest hop router device (104b) participating in the hop-limited downlink source routing. A distribution method comprising: a step (330) in which the controller (1030) of the communication devices (204a to 204n) determines, based on the source routing control information, whether the received source routing information should be repeated to the member devices (206a to 206n) by the wireless communication unit (1036) of the communication devices (204a to 204n) using the identifier of the communication devices (204a to 204n) set as the source routing identifier, or by the source routing identifier of the received source routing information, the controller (1030) of the communication devices (204a to 204n).

15. Computer program (1046) which, when executed by a computer, includes instructions causing the computer to perform at least the steps of the method according to claim 12 or claim 14.

16. A tangible, non-volatile, computer-readable medium comprising the computer program (1046) described in claim 15.

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