Control unit, node and method for addressing multicast transmissions in a wireless network

Control unit, node and method for addressing multicast transmission in wireless network

The present invention relates to a control unit, node and method for addressing multicast data packets in a wireless network.

Recently, wireless mesh networks have attracted more and more attention, such as remote control for lighting systems, building automation, monitoring applications, sensor systems, and medical applications. In particular, remote management of one of the outdoor luminaires (so-called teletype management) is becoming more and more important. On the one hand, this is driven by environmental considerations, because the telex management system enables the use of different dimming patterns (for example) according to a time, weather conditions, and seasons, allowing more energy-efficient use of outdoor lighting systems. On the other hand, this is also driven by economic reasons. This is because the increase in energy efficiency also reduces operating costs. In addition, the system can remotely monitor power usage and detect lamp failures, which allows to determine the best time to repair the luminaire or replace the lamp.

Current radio frequency (RF)-based wireless solutions use a star network topology or a mesh network topology. In a star network, a control center has a direct wireless communication path to each node in the network. However, this usually requires a control center like a high-power/high-sensitivity base station to be placed at a high location (for example, on the top of a building), which makes the solution difficult to deploy and expensive. In a mesh network, a plurality of nodes generally do not directly communicate with the control center, but communicate via so-called multi-hop communication. In a multi-hop communication, a data packet is transmitted from a sender node to a destination node via one or more intermediate nodes. Nodes function as routers to transmit data packets from neighboring nodes to nodes that are too far away to be reached in a single hop, resulting in a network that can span large distances. By dividing the long distance into a series of shorter jumps, the signal strength is maintained. Therefore, routing is performed by all nodes of a mesh network to determine which neighboring node the data packet is to be sent to. Therefore, a mesh network is a very powerful and stable network with high connectivity and therefore high redundancy and reliability.

In the prior art, mesh network transmission technologies can be divided into two groups: mesh networks based on anycast and mesh networks based on routing. In a mesh network based on anycast, all data packets are forwarded by all nodes in the network. Therefore, a node does not have to make complex routing decisions but only broadcasts data packets. By this means, the technology has become quite powerful. However, in large networks, data additions attributed to forwarding affect the total achievable data rate. In addition, data packet collisions are more likely to occur, thereby further reducing overall performance. Therefore, the main problem of this solution is scalability. Routing-based mesh networks can be further divided into forward-looking solutions and reactive solutions. In a mesh network based on forward-looking routing, all required network paths are stored in the routing table of each node. For example, the latest routing table can be maintained by sending periodic beacon messages to neighboring nodes to find efficient routing paths. Although data transmission is very efficient in this kind of network, the scalability is still low, because in a large network, the forward-looking update of the routing table consumes most of the network resources. In addition, the routing table will increase with the size of the network. In addition, network configuration requires time and resources to build routing tables. In contrast, reactive solutions avoid permanent additions and large routing tables by discovering routes on demand. Reactive solutions use Anycast to discover network paths and cache active routes or nodes. When the route is almost not only used for a single data packet, it is more efficient to broadcast the data packet instead of performing a route discovery. If the route is kept long enough to avoid frequent routing, the reactive solution is inferior to the forward-looking solution. An example of using a mesh network protocol based on reactive routing in ZigBee. However, the main problem of this protocol scheme is still the scalability of the network.

In order to control a large number of nodes, efficient communication methods (such as multicast) are indispensable to achieve the desired scalability. Multicast refers to the transmission of a data packet to several (but not all) destination nodes. Therefore, only one multicast data packet is required, instead of separately transmitting a data packet to each destination node. Generally, a multicast data packet contains a multicast group address or identification corresponding to a predefined multicast group containing a number of nodes. However, although multicast is a known concept, when a multicast group is defined during a delegation phase of the system, the previous approach does not consider key parameters, such as the geographic characteristics and background characteristics of the network nodes. In particular, for large-scale sensor or actuator networks (such as lighting systems used to illuminate streets or other public venues), these features are essentially functions and controls. For example, luminaire nodes located in a lighting system in the same street are very likely to share the same control requirements. In addition, the generation of a multicast group is usually performed by assigning a multicast group identification to individual nodes during system delegation. Therefore, the multicast group is predefined and it is not possible to simply modify the multicast group. In order to create a new multicast group in the prior art network, an extensive configuration routine is required, in which each node included in the new multicast group must be individually subscribed and then must be notified about the multicast group Recognition. However, this is a very time-consuming task and causes a large data addition to significantly increase the network load. In particular, this setting procedure is very disadvantageous when generating a multicast group that is used only once or includes a large number of nodes. Therefore, when only some interactions with a set of nodes are required in the prior art network, unicast data transmission is better, rather than generating a new multicast group. However, this approach is not suitable for high scalability. Therefore, the major shortcomings of ordinary wireless networks are the lengthy and tedious configuration of the network, the inflexibility and default definition of multicast groups, and the extensive settings of new multicast groups regarding time and network resources.

In many cases, it is better to modify the predefined multicast group as needed to include or exclude nodes from the multicast group communication. In addition, an efficient method for addressing an arbitrary set of nodes is required, which is suitable for both high scalability and flexible control of a large wireless network.

WO 2009/128001 describes a method for appointing the configuration of one of the devices communicating with each other on a wireless network control system, in which the unique identification of each device to be installed is read and edited in an inventory of one of the installed devices.

In view of the above shortcomings and problems in the prior art, one object of the present invention is to provide a control unit and method for addressing nodes of a wireless network in a flexible manner while maintaining network scalability and communication efficiency.

The present invention is based on the concept that at least one addressee condition is included in a multicast data packet, and a node addressed as a destination node must satisfy this concept. Therefore, this addressee condition defines one of the addressee groups of the destination node without any preset or previous grouping of the multicast group. Then, any broadcast or broadcast can be used to transmit the multicast data packet. In this case, many or even all nodes of the network will receive the multicast data packet, but the node that is only conditionally addressed by the addressee will act as the destination node of the data packet, (for example) decode the data packet and data This uses the content of the data packet. By this means, it is possible to avoid complex and time-consuming explicit generation of multicast groups, thus avoiding extensive use of network resources and providing high scalability and communication flexibility. This is especially useful for ad-hoc or on-demand addressing, addressing a large number of destination nodes or groups of addressees that will be addressed only once or rarely.

According to an aspect of the present invention, a control unit having a wireless network with a plurality of nodes is provided. The control unit is adapted so that an addressee condition is included in a multicast data packet to generate an addressee group of destination nodes. Therefore, multiple nodes can be addressed without unicast data transmission to individual destination nodes or pre-grouping into a multicast group with a preset group address or group identification. This significantly increases the flexibility and efficiency of data transmission and control in a wireless network. The control unit may include or be installed in at least one of a network node, a collector node, or a control center of the network.

The wireless network can have a mesh topology, in which each node can function as a router. This network has increased redundancy and reliability. Preferably, the nodes of the wireless network are static, as in the case where the wireless network is mainly a network of large actuators or sensors (such as lighting systems in public places). Alternatively or in addition, the location of at least some nodes may be known by at least some of the other nodes of the network.

In an example, the addressee conditions may be related to node characteristics, such as network characteristics of a respective node, a geographic location, background characteristics, and additional characteristics. Network characteristics can refer to: a node address or node identification; the node is assigned to a multicast group; a function of a node in the wireless network (for example, whether the node is a collector node); A location within the network (for example, the hop distance from the node to a collector node); or similar characteristics. The geographic location of a node can refer to: GPS coordinates; a geometric location within a wireless network defined in arbitrary units; a location relative to other components of the network; or similar characteristics. In addition, the background feature may correspond to a nearby street, a building, or a place of interest, etc. However, the additional feature may refer to a firmware version of the node itself, a manufacturing type, or other properties. Since nodes sharing at least some node characteristics are likely to have the same control or communication requirements, it may be advantageous to cluster them as a group of addressees of a multicast data packet by including a corresponding addressee condition. For example, in a fly-by-wire management network used to control a large sensor or actuator network (such as a lighting system), it is therefore possible to define at least one common node characteristic (for example, located on the same designated street). Or have the same software version or lamp type) as the addressee condition to group the luminaire nodes together.

Preferably, in addition to at least one addressee condition included in the multicast data packet, the address information corresponding to a multicast group is also included in the multicast data packet, so that by combining the address information and the address information The conditions define the addressee group of the destination node. In this case, the addressee condition can be used to modify the multicast group addressed by the address information according to requirements (for example, special or on-demand). When the addressing information and the addressee conditions are included in the multicast data packet, they are all considered by a node receiving the data packet to determine whether the node belongs to the addressee group of the data packet. The addressing information may include geographic addressing information that defines a multicast group by designating a geographic area, and all nodes in the geographic area are addressed as destination nodes of the multicast data packet. For example, the geographic addressing information can specify a GPS location and a radius, and the specified GPS location is the center of a circular geographic area with a specified radius. Alternatively, the geographic addressing information may be related to the interval of GPS positions, so that the designated geographic area has a rectangular shape. Other geographic-based location data (for example, relative location coordinates or location coordinates defined in a map deployed only on one of the networks) can also be used instead of globally defined GPS locations. Therefore, geographic addressing information can be used to define a geographic area that usually has a simple geometric shape. Alternatively or in addition, the addressing information may include a group address or group identification of a predefined group of nodes (for example, a multicast group). For example, during a delegation phase of the network, these predefined multicast groups can be set to have an assigned group identification or group address. Therefore, if a node corresponds to the addressing information and satisfies the addressee condition, the node will act as a destination node of the multicast data packet. Using an example of a lighting system, the GPS location of a hospital and a radius of 200 m can be included in the multicast data packet as geographic addressing information, but a further addressee condition can include the background characteristics belonging to an access channel of the hospital . Therefore, in addition to the use of the addressee condition, the use of the addressing information can combine the advantages of a simple but general addressing with the advantages of a fine addressing. With these methods, the number of data packets can be reduced, thereby increasing the efficiency and scalability of the network. In addition, the addressing information and the addressee conditions can be based on different routing algorithms, such as the routing based on geography and characteristics in the above example. Therefore, different routing algorithms become compatible and can combine their advantages.

In a preferred embodiment, the addressee condition relates to an open addressing condition, whereby not only the nodes included in the multicast group of the address information are addressed, but also the nodes belonging to one or more predefined multicast groups can be addressed All nodes (at least one of them is included in the multicast group corresponding to the address information). In this case, an addressee condition and certain address information can be included in the multicast data packet, where the address information corresponds to a predefined multicast group. Then, if one of the nodes included in the multicast group corresponding to the addressing information is also a member of another preset multicast group, all nodes of this other predefined multicast group are also addressed as destination nodes. This can be particularly advantageous if the addressing information is based on one of the geographic routing information. As an example, if the geographic addressing information defines an intersection and if the luminaire nodes of a street are pre-grouped in a predefined multicast group, it is sufficient that the addressing information and open addressing identification of the intersection are included in the multicast data In the packet, the luminaire node at the intersection and all the luminaire nodes in the street leading to the intersection are addressed. However, the alleyways of these streets are not located. In other words, when a multicast group is addressed by addressing information and including an addressee condition regarding open addressing, the nodes of the multicast group corresponding to the addressing information and all other multicast groups (such as Overlap with the multicast group corresponding to the address information). Therefore, a precise addressing can be performed in a very efficient manner. By this means, the effective load of a single multicast data packet and the total number of data packets can be reduced.

In a further embodiment, the addressee condition may be related to a filter condition for selecting a subset of nodes in a predefined multicast group. This multicast group can be related to a multicast group defined by specific address information contained in the data packet. The condition for screening addressees may include a disclaimer, and the disclaimer is used to deselect nodes of the multicast group. This can be expressed as negative filtering or masking of nodes. In logical terms, this filter condition can be considered as a "AND" NOT)" condition. Similarly, when considering the multicast group defined by the addressing information as a first set and considering the nodes that meet the filtering conditions as a second set, the disclaimer can be used as a set of difference operators, for example, the first set All nodes in the set have no nodes in the second set. Alternatively or in addition, the filter condition may include an additional or mandatory condition. In this case, when the address information is also included in the multicast data packet, only the nodes of the multicast group defined by the address information are destination nodes, and they also meet the mandatory filtering conditions. This can indicate active screening. In logical terms, the additional mandatory conditions can be called "AND" conditions, or in set theory terms, the mandatory conditions can be regarded as a crossover operator that forms an intersection between sets. Alternatively or in addition, the addressee condition may include an optional condition. When certain address information is included in a data packet of a multicast group that defines one of the nodes, all nodes belonging to this multicast group and all nodes meeting the selection conditions are addressed as destination nodes. By this means, the predefined or geographically defined multicast group can be extended without assigning a group address to this addressee group. In logical terms, this selection condition can be called an "OR" condition, or in set theory terms, it is called a union operator that combines several sets.

In addition, the control unit can be adapted to generate a new multicast group based on node characteristics. As an example for generating a new multicast group, the control unit can cluster all nodes with the same software version or in the same street in a multicast group. The control unit may be further adapted to allocate a group address or identify to the new multicast group. The group identification can be communicated to the nodes of the multicast group by transmitting at least one data packet containing the group identification and the node identifications of individual nodes belonging to the multicast group. In general, a group or node identification can also refer to a group or node address, respectively. The control unit may be adapted to generate a new multicast group by using map information combined with the geographic location information of the node. Therefore, individual nodes can be localized in a map and can then be grouped in one or more multicast groups based on their isolocation. For example, the map can be divided into a plurality of sections, so that nodes included in a section can be defined as a multicast group. Alternatively or in addition, background characteristics can be used, ie, luminaire nodes of the same street or all luminaire nodes in the vicinity of one or more hospitals can be clustered in a multicast group. The control unit may use image analysis together with the geographic location data of the nodes to assign the nodes to one or more multicast groups. Here, the control unit may be able to recognize the background characteristics of the individual nodes based on their relative positions or the configuration of their own nodes. In an example of a street lighting system, nodes arranged along a straight line can therefore be recognized as nodes localized in the same street, and so on. In addition, when a multicast group is generated, third-party information (such as the geographic location of important buildings or places (e.g., hospitals, government buildings, airports, seaports, and the like)) can be used for the control unit. By this means, multicast groups can be automatically defined based on geographic characteristics or background characteristics.

Preferably, the control unit can be adapted to generate one or more composite multicast groups by combining at least one multicast group with at least one node or at least one other predefined multicast group or one of the others . Therefore, a multicast group can be a simple multicast group or a composite multicast group. Preferably, a composite multicast group includes nodes with the same or similar communication or control requirements or characteristics. The composite multicast group may only be defined locally at the control unit, that is, the control unit processes the nodes or components of the composite multicast group as a multicast group, but when transmitting a multicast data packet , Address each component individually (for example, a predefined multicast group or node). That is, if a composite multicast group is composed of a multicast group and a single node, a multicast data packet is transmitted to the multicast group and a unicast data packet is transmitted to the single node. Alternatively, a single data packet containing addressing information of both the multicast group and the single node is transmitted. The local definition of the composite multicast group is conducive to the composite multicast group that will be rarely used. Alternatively, the composite multicast group can be defined globally by a composite identification or a composite address corresponding to the composite multicast group. The composite identification can be communicated to each node of the composite multicast group and stored at each node as a group identification. This can be useful when establishing a new frequently used multicast group following a commissioning phase.

According to another aspect of the present invention, there is provided a node comprising a wireless network of a plurality of nodes, wherein the node is adapted to be based on at least one or more addressee conditions included in a received multicast data packet Know whether it is addressed as a destination node of the multicast data packet. If the node is addressed and therefore belongs to the addressee group of the data packet, then the node functions as a destination node of the multicast data packet. For example, if the data packet includes an operation command, the destination node is operated according to the command contained in the multicast data packet. When the node determines whether it is a destination node, in addition to considering at least one addressee condition, the node also considers at least certain address information. Therefore, the node is adapted to determine whether it is part of a group of addressees generated by a control unit according to one of the embodiments described above. In a preferred embodiment, the node is a sensor or actuator node of a sensor or actuator network, such as a luminaire node of a lighting system.

In a further aspect of the present invention, there is provided a system for addressing nodes in a wireless network, the network including a plurality of nodes, wherein the system includes a control unit according to any of the embodiments described above and / Or at least one of at least one node. Preferably, the system is a sensor or actuator system, such as a lighting system. Therefore, in a preferred embodiment, at least some of the nodes and/or a collector node are associated with luminaire nodes of a lighting system. In addition, the system according to the present invention (for example) can be used in telex management of a lighting system to turn on/off the luminaire node, to control the dimming pattern of the luminaire node and/or to update the schedule of the luminaire node Or software. Using a system according to the present invention to manage a lighting system by telex will result in a high-efficiency lighting system with high scalability.

According to another aspect of the present invention, a method for addressing a node in a wireless network including a plurality of nodes is provided. In this method, one of the addressee groups of a plurality of destination nodes can be generated by including at least one addressee condition in a multicast data packet. By this means, the multicast is configured without including a single node address of an individual node in the data packet or by assigning a corresponding group address to individual nodes of a multicast group by means of unicast transmission In the case of a group, the multicast data packet can be transmitted to an arbitrary group of addressees.

Preferred applications of the present invention are actuator networks, sensor networks, or lighting systems, such as outdoor lighting systems (for example, for streets, parking lots, and public areas) and indoor lighting systems for general area lighting ( For example, it is used in shopping malls, arenas, parking lots, platforms, tunnels, etc.). In the following, an example of an outdoor lighting system for street lighting will be used to further illustrate the present invention, but the present invention is not limited to this application. In the field of lighting control, the telex management of outdoor luminaires via radio frequency network technology has attracted more and more attention. In particular, solutions for large-scale installation with more than 200 luminaire segments are used.

In Figure 1, a typical network with a mesh topology is shown. A plurality of nodes 10 (N) are connected to each other through a wireless communication path 40. Some of the nodes 10 function as collector nodes 50 (N/DC), which receive data packets from surrounding nodes 10 via single-hop or multi-hop transmission and transmit the data packets to a control center 60, and vice versa NS. Therefore, the collector nodes 50 can operate in the manner of a gateway between the nodes 10 and the control center 60. If necessary, these collector nodes themselves can act as control centers. The wireless communication path 40 between the nodes 10 and the collector node 50 can be constituted by RF transmission, and the connection 70 between the collector nodes 50 and the control center 60 can use the Internet, mobile communication network, radio System or other wired or wireless data transmission system. Therefore, the nodes 10 and the collector nodes 50 include a transceiver for transmitting or receiving data packets via the wireless communication path 40 (eg, via RF transmission). Since RF transmission does not require high transmission power and is easy to implement and deploy, it can reduce the cost of using devices to set up and operate a network. This is especially important for large-scale RF networks (for example, an RF telex management network, one of the lighting systems). However, data packet transmission may alternatively use infrared communication, free space visible light communication, or power line communication. In the following, a data packet transmitted from a node 10 to the collector node 50 is referred to as an uplink data packet, but a data packet transmitted from the collector node 50 to one or more nodes 10 refers to a downlink data packet. In addition, when a data packet is addressed to all nodes 10 in the network, this is called broadcast, but a data packet directed to a group of nodes 10 is called a multicast or groupcast data packet. A data packet directed to a single node 10 represents a unicast data packet.

In a fly-by-wire management system for lighting control, the number of luminaire nodes 10 is extremely high. Therefore, the size of the network is very large, especially when compared to an ordinary wireless mesh network that usually contains less than 200 nodes. In addition, due to cost considerations, the node 10 generally has limited processing capabilities, so that the processing and memory resources in the luminaire node 10 will be limited. Therefore, the communication protocol used to transmit data packets between a single node 10 should consider the limited resources of efficient and fast data packet transmission. In addition, compared to other so-called special mesh networks, the telex management system for an outdoor lighting control network is static, that is, the node 10 does not move. However, it may be necessary to flexibly define the addressee group of the destination node, for example due to change requirements. In a lighting system, all nodes 10 can be connected to the main power source. Therefore, network changes will be mainly due to environmental changes, such as communications. If the nodes 10 are stationary, the system can know the physical locations (such as GPS coordinates) of the nodes 10, thereby enabling routing based on geography or location. In addition, the telex management of an outdoor lighting system does not require a high data throughput. This means that most data communications consist of data packets that do not require strict time (for example, status report data, statistics, schedule updates, or similar data). In addition, in a lighting system (such as a street lighting system), the communication is very asymmetrical. The luminaire node 10 generates most of the traffic, for example, reporting its status, its dimming profile, sensor value, or power usage to the control center 60. Other communications are composed of control commands from the control center 60 to different nodes 10 (for example, for adjusting a dimming pattern or turning on/off lamps). In the unicast, multicast or broadcast mode, the traffic from the control center 60 or the data collector 50 to the node 10 is composed of 1:N traffic. Therefore, although it is worth using efficient collector-oriented routing protocols for the uplink, the downlink path will require much more cost to generate or maintain, because the downlink path is rarely used frequently. Therefore, the downlink data is transmitted from the collector node 50 to one or more destination nodes B by broadcast, as shown in FIG. 2. In an broadcast process, the data packet is forwarded to all luminaire nodes 10 (arrow) in the network, but only the destination node B (shaded circle) (its node address is included in the broadcast data packet) ) Decode the data packet. This anycast method can be applied to unicast, multicast or broadcast downlink data packets. Preferably, the nodes 10 that usually need the same data transmission are grouped into a multicast group G_i. Therefore, for this multicast group G_iThe data transmission of the node 10 is a multicast data packet. Therefore, a control center 60 or a collector node 50 can address each node separately by a multicast transmission instead of using a unicast transmission, and be linked to a multicast group G_iA number of nodes 10 communicate.

When setting up a lighting system, a commissioning phase occurs before the system becomes operational. In one case, an appointed person configures each node 10 in the network on a separate basis, and provides information (such as its GPS coordinates) and data (such as node 10 being assigned to a multicast group) to each node 10 Group G_iOne group identification, one node identification, node address, street pole identification or street identification or similar identification). This can be achieved by a hand-held device that has street layout information stored locally or retrieves this information by querying the street corresponding to its current geographic location via the Internet or the like. In the simplest case, the appointed person can also immediately type the street identification into the handheld device. By this means, a simple multicast group G can also be generated by assigning a group address to a single node 10_i。

In order to generate a new multicast group, the control center 60 or a collector node 50 can use the GPS location data of the node 10 in combination with a city map or street map to generate a multicast group G_i. By this means, the control center 60 or the collector node 50 can generate a deployment map representing, for example, one of the absolute positions of all the luminaire nodes 10 in a city. Preferably, the location of the building or structure of interest is also added to this map, for example, as provided by a third party and used to generate the multicast group G_iAfter consideration, set up data. An alternative way for the control center 60 or the collector node 50 to set the multicast group (which can lose map information) is to use image analysis. To this end, the control center 60 or the collector node 50 uses the absolute or relative geographic location of the nodes 10 to generate a deployment map, thereby identifying the positions of the nodes 10 relative to each other. Then, image analysis can be used to identify streets, intersections, junctions, market squares, open areas, and similar places based on the layout of the deployed map. Thereafter, nodes 10 can be allocated to different multicast groups G based on their positions relative to the identified structure_i。

In addition, the control center 60 or the collector node 50 can generate a new multicast group G based on a geographic location, background characteristics, network characteristics, or other additional characteristics of a node 10, or a combination thereof._i. The geographic location of a node 10 can refer to an absolute geographic location defined by GPS data or a relative distance between individual nodes 10 or a hop distance from a node 10 to the collector node 50. Relative geographic location. The network characteristics are related to the function of a node 10 in the network, for example, whether the node 10 is a collector node 50 or not. Similarly, background characteristics include the surrounding or background of a node 10 (for example, the street of the node 10, the buildings or structures of interest near the node 10, an operating state of the node 10, and the detection by the node 10). An alarm condition and the like) define the functional nature of the node 10. In contrast, additional features include all static hardware or software properties of individual nodes 10, such as one luminaire, one illuminance or light power, one firmware version, one luminaire type, and so on.

As illustrated in FIG. 3, for example, the control center 60 or the collector node 50 may be assigned to a hospital H₁All nodes 10 within a certain distance belong to the same multicast group G₁. Here, for example, by designating the hospital H₁Geographical location and a radius, and geographically define the multicast group G₁, All nodes 10 within the radius belong to the multicast group G₁. In general, this geographically defined multicast group G_iHas a very simple shape. Multicast group G₂And G₃It relates to a preset multicast group including, for example, nodes 10 that have been individually assigned to the multicast group based on background characteristics or similar characteristics. Therefore, when making a multicast group G_iWhen the group address of is included in a multicast data packet, all nodes 10 of the group are addressed as destination nodes 11.

As shown in FIG. 4, the control center 60 or the collector node 50 can also be generated, for example, by combining a multicast group with another multicast group or a single node 10, or a combination thereof based on the characteristics of the node. A composite multicast group CG. Here, the multicast group G_iIt can be a composite multicast group CG. For example, as shown in Figure 4, the combination can be included in the hospital H_iAll multicast groups G of neighboring node 10_i, Therefore, about the hospital H_iOne of the composite multicast group CG. Therefore, the simple multicast group G₁, G₂And G₃The nodes 10 can be addressed together as the destination node 11 of the multicast data packet addressed to one of the composite multicast groups CG, instead of transmitting the data packets to the simple multicast groups G₁, G₂And G₃. If multicast group G_iThis is especially advantageous if they share the same node characteristics or control requirements and are used regularly. In one embodiment, the multicast group G₁, G₂And G₃Can be notified that they have reached these individual multicast groups G₁, G₂And G₃The multicast transmission is allocated to the composite multicast group CG. Alternatively, it may be intended to maintain the localization of the composite multicast group CG at the control center 60 or the collector node 50. In this case, for example, when preparing for control, command or update or the like, the composite group CG is regarded as a multicast group G in the control center 60 or the collector node 50_i. However, when a data packet must be transmitted to a composite group CG defined only locally, three multicast data packets are transmitted for G₁, G₂And G₃. If multicast group G₁, G₂And G₃The group address can be included in a data packet, and the transmission may include these multicast groups G₁, G₂And G₃Only one multicast data packet for all group addresses. Belong to these multicast groups G₁, G₂And G₃Any node 10 of at least one of them will act as the destination node 11 and decode the received data packet. By this means, the generation of a new multicast group or a new composite group can be efficiently performed at a later stage (for example, after a commissioning phase of a network).

After a multicast group G has been generated_iAfter that, save a group address or identification ID (G_i) Together with the identification of the node that contains the node 10. Similarly, when a composite multicast group CG is generated, the group identification ID (CG) is stored together with the identification of the included network element. It is also possible to use the corresponding address instead of the identification, and vice versa. This information is stored at least locally at the control center 60, but preferably also at the contained node 10. In the latter case, the transmission includes the respective node addresses and the generated multicast group G_iOne of the group addresses of a unicast data packet or a multicast data packet that contains the group address and all the included node addresses by anycast, the multicast group G_iThe nodes 10 of can be notified about their group assignments. However, this group setting should only be used for frequently used multicast group G_iThis is because the additional data items required for the group setting are quite large.

As mentioned above, nodes 10 with the same node characteristics usually need to use the same control data or information data for data transmission. However, node 10 is not always pre-grouped in a multicast group G_i, The multicast group G_iIt can be used to address these nodes 10 together to transmit a single multicast data packet. In addition, a new multicast group G should be generated on demand_iThe network load is significantly increased because the control center 60 or the collector node 50 must notify the node 10 about a corresponding group address. In addition, set all possible multicast groups G_iIt will require a lot of time and network resources and will also result in a highly complex network, which requires a large number of memory group addresses at individual nodes 10. In addition, the newly generated multicast group G is also fixed or unchanged._i. In order to save network resources, when the same data must be provided to more than one node 10, multicast data packets should be used. Therefore, there is a need for more flexible and more precise means of addressing a multicast data packet.

In Figure 5A, an address format according to the present invention is shown. According to the present invention, the data field for a data packet to be addressed includes a field for the addressee condition. The addressee condition preferably relates to at least some node characteristics shared by the destination node 11 of the data packet. For example, network characteristics can be used to define the addressee group of the destination node 11. These characteristics are related to the function or location of the respective node 10 in the wireless network, such as whether the node 10 is a collector node 50 or is based on The hop distance between the node 10 and a collector node 50. The node characteristics can also be related to the geographic location of the respective node 10 defined by GPS data or arbitrarily defined coordinates x and y, for example. In addition, the background characteristics of a node can be used, which is related to a state of the node 10 or its surroundings, such as a street of the luminaire node 10, a building or place of interest near the node 10, the illuminator node An operating state of 10, sensor data or alarm conditions detected by the luminaire node 10, and the like. In addition, the additional characteristics of a node 10 can be used for addressing the fixed properties of the node 10 (such as an average power consumption, a manufacturing type, a lamp type, a software version or driving capability, etc.). Therefore, by including an addressee condition in a data packet, a plurality of nodes 10 can be addressed based on having one or more node characteristics in common.

Preferably, the data packet further includes a certain address information field. The address information field may include the identification or address of a predefined network element, such as the identification of a multicast group Gi or a single node 10. Geographic addressing information can also be included in the addressing information field instead of the predefined identification or address, or in addition to the predefined identification or address being included in the addressing information field, geographic addressing information can also be included in the addressing information Field. For example, by including location data (such as a hospital designated as a center of a circular area H₁And a radius R₁GPS data), making the location around the hospital H₁One of the radius is R₁All nodes within the circle 10. For the hospital H in Figure 4₁Describe an example of this geographic addressing. Therefore, you can use geographic addressing information or use one of the predefined multicast groups multicast identification ID (G₁) To address the multicast group G₁. Of course, geographic addressing is not limited to circular areas, but rectangular areas or other areas with a simple geometric shape can also be defined. If it is a rectangular area, you can specify the interval between coordinates x and y to define a geographic location in the addressing information field, such as 10<x<15 and 300<y<510 in arbitrary units. If the field of the addressing information is empty, the data packet is directed to one of all nodes 10 of the network to broadcast the data packet. Therefore, there is no need to include addressing information in the data packet.

In FIG. 5B, two possibilities for addressing the composite group CG shown in FIG. 4 are illustrated. As shown in the upper part of FIG. 5B, a given group identification ID (CG) can be used to address the composite multicast group CG. However, for this, it is necessary to preset the composite multicast group CG (this involves assigning group identification to the associated node 10) or only set the composite multicast group CG locally at the control center 60 or the collector node 50, Therefore, it usually needs to be transmitted separately to the included preset multicast group G₁, G₂And G₃. According to the present invention, the composite group CG can also, for example, use an addressee condition and be addressed as shown in the lower part of FIG. 5B. In this example, the addressee condition corresponds to background information {about a hospital H_i}, identify about a hospital H_iAll of the nodes 10 serve as destination nodes 11. Background information (ie, a node 10 is about a hospital H_i) Can be stored locally at each node 10. In this example, therefore, the composite group CG can also be addressed by including only one addressee condition in the multicast data packet without any addressing information. Therefore, the addressee condition can be used alone to address a multicast data packet.

In Figures 6 to 10, further examples of addressee conditions are shown. In Figure 6A, a preset multicast group G₁Only some nodes should be addressed as destination node 11. This can be achieved by including a screening addressee condition that is used to select from the multicast group G₁The node 10 selects a subset of the destination node 11. This filter condition can be: a negative condition, which is used to deselect or mask the multicast group G₁The node 10, as shown in the upper part of Fig. 6B; or a positive condition, which represents an additional mandatory condition for specifying the selected destination node 11, as shown in the lower part of Fig. 6B. By this means, a predefined multicast group G can be freely identified in the addressing information field_iFilter out a subset of destination nodes 11, and therefore provide to modify the predefined multicast group G_iThe possibility.

In Figure 7, it is shown that a previously existing multicast group G is modified based on the geographic selection criteria.₁Another instance. Here, you can address the predefined multicast group G in the addressing information field₁And by assuming that the position coordinate x of a node 10 must not be less than 10, the addressee group of the destination node 11 is selected. This is a further example of a mandatory addressee condition. Alternatively, the mandatory screening condition may require that a destination node 11 must have a position coordinate x greater than 10. This negative filtering condition can also be regarded as a condition for deselecting some nodes 10 addressed in the addressing information field.

Although Figures 6 and 7 illustrate the addressing of a predefined multicast group G_iA subset of the node 10, but it is also necessary to make a previously existing multicast group G_iExpand one or more nodes 10. To this end, a condition for selecting or replacing the addressee can be included in the data packet. As shown in Figure 8A, the destination node 11 is connected to the predefined multicast group G₁Or distribute to hospital H along a road R₁. As shown in Figure 8B, the group identification ID (G₁) Together with the selection of the addressee conditions (referring to the location on the road R) to address these destination nodes 11. Similarly, using the example of the composite multicast group CG in FIG. 4, it is also possible to include the default multicast group G₂Or G₃The group identifier ID (G₂) And ID (G₃) Serves as addressing information and includes a geographic address as an addressee condition to address this composite multicast group CG, as shown in FIG. 8C. Here, all nodes 10 are the destination node 11 of the data packet, and they are the default multicast group G₂Or G₃Part of or its equivalent node position r_iLocated in own hospital H₁Radius R₁Inside. Therefore, by means of this addressee condition, which also represents the replacement or selection condition, the existing multicast group can be expanded to the node 10 with a specific node characteristic.

Sometimes, it is necessary to address a preset multicast group G1 together with other preset multicast groups Gi, which at least partially overlap with the multicast group G1. For example, if G1 corresponds to a group of luminaire nodes 10 around a hospital H1, it may be necessary to control the luminaire nodes around the hospital H1 and the luminaire nodes 10 located on the street leading to the hospital H1. If the street luminaire node 10 is approved in the predefined multicast groups G2 and G4 (see Figure 9A), open addressing can be used instead of including a single multicast group ID (G1), ID (G2) and ID (G4) group identification. As shown in the second example of FIG. 9B, in this case, only the address center multicast group G1 must be clearly identified. However, when the open addressing identification is included in the addressee condition field, the addressing also belongs to a multicast All nodes 11 of the group (the multicast group has at least one node included in the addressed multicast group G1). Open addressing can also be combined with further addressee conditions selected from the multicast group considered by open addressing nodes with specific node characteristics. In an example, open addressing can be performed as follows. If in addition to addressing information (such as a group identification or geographic addressing information) included in the data packet, an open addressing identification is also included in the data packet, the destination node 11 corresponding to the addressing information may further forward the The data packet is accompanied by the group identification or group address of the multicast group to which the destination node 11 belongs. If any node 10 that receives a data packet but does not belong to the addressee group specified by the addressing information has the same group ID as one of the group IDs added in the data packet, then any node 10 will behave like A destination node 11. This node 11 that is not addressed by the addressing information but has a group ID corresponding to a newly added ID can be further forwarded but does not contain other group IDs.

Geographic addressing is used in Figure 10 to further illustrate this principle. Here, the multicast group G1 is defined by geographical addressing information (for example, GPS data by specifying a center of a circle and the radius of the circle). In this case, all nodes 10 in the circle belong to the multicast group G1. However, alternatively, a rectangular area can be specified by including the position coordinate interval. As mentioned earlier, the location coordinates can be GPS-based or arbitrarily defined in the network. When using geographic addressing, specify a geographic area that generally has a very simple geometric shape. Therefore, due to this basic specification of the addressee group, some nodes 10 can be omitted unintentionally. For example, nodes 10 with the same background characteristics (for example, located in the same street) should also be addressed, even though they do not fall within the designated geographic area. In other words, when addressing information (for example, based on geographic or group identification, used to address a multicast group G1) and an open addressing identification are included in the data packet, the multicast specified by the addressing information is addressed Group G1 and all multicast groups Gi that at least partially overlap with the designated multicast group G1.

In the example of FIG. 10A, a node A included in the multicast group G1 corresponding to the address information also belongs to a second multicast group G2. If node A receives a data packet containing addressing information corresponding to multicast group G1 and an open addressing identification, node A will include group identifications of all other predefined multicast groups G2 belonging to the data packet and forward Pass the data packet. If a node 10 of the multicast group G2 receives the modified data packet, the node 10 will act as a destination node 11, although it does not correspond to the original address of the data packet. This Node B can further forward the data packet but does not include the new group identification.

It should be noted that in the full description, a multicast group Gi may be about a simple multicast group composed of individual nodes 10 or about a composite multicast group CG, which may include individual nodes 10 , Simple multicast group, other composite multicast group, or a combination thereof. The multicast group Gi can be predefined as having a group identification or group address known to all nodes 10 belonging to the multicast group Gi, or the multicast group can be geographically addressed by specifying a specific geographic area Gi. The addressing based on both geography and recognition is included as the addressing information in the corresponding data field of the data packet. However, these addressing modes only allow a very rough addressing. In order to address a plurality of nodes 10 belonging to different multicast groups Gi or not belonging to a multicast group at all, extensive addressing information must be included in the data packet, which results in a large data addition. This is solved according to the present invention by including an addressee condition in the data packet, whereby a node 10 sharing at least a specified node characteristic can be selected as the destination node 11 or a multicast group Gi can be modified thereby. By this means, a very fine addressing can be performed without increasing the network load or requiring the time-consuming definition of multicast groups. This is especially useful for groups of addressees of destination nodes 11 that are not reused or are very large.

<p>10. . . Node/illuminator node</p><p>11. . . Destination node</p><p>40. . . Wireless communication path</p><p>50. . . Collector node/data collector</p><p>60. . . control center</p><p>70. . . Connection between collector node 50 and control center 60</p><p>A. . . node</p><p>B. . . Destination node</p><p>CG. . . Composite multicast group</p><p>G₁. . . Multicast group/default multicast group</p><p>G₂. . . Multicast group/preset multicast group/predefined multicast group/second multicast group</p><p>G₃. . . Multicast group/default multicast group</p><p>G₄. . . Pre-defined multicast group</p><p>H₁. . . hospital</p><p>R. . . the way</p>

Figure 1 illustrates an example of a wireless mesh network;

Figure 2 schematically illustrates a multicast transmission;

Figure 3 illustrates an example of generating a new multicast group based on node characteristics;

Figure 4 illustrates the generation of a composite multicast group;

5A illustrates a data field of a multicast data packet according to an embodiment of the present invention;

Figure 5B illustrates a possible way of addressing the composite multicast group of Figure 4;

Figure 6A illustrates that an addressee group of destination nodes is a subset of a multicast group;

Figure 6B illustrates a possible way of addressing the addressee group of the destination node of Figure 6A;

Figure 7A illustrates another group of possible addressees of destination nodes according to the present invention;

Figure 7B illustrates a possible way of addressing the addressee group of Figure 7A;

FIG. 8A illustrates a group of further possible addressees of one of the destination nodes according to the present invention;

Figure 8B illustrates one possible way of addressing the addressee group of Figure 8A;

Figure 8C illustrates a possible way of addressing the composite multicast group of Figure 4;

FIG. 9A illustrates a group of further possible addressees of a destination node according to the present invention;

Figure 9B illustrates one possible way of addressing the addressee group of Figure 9A;

Figure 10A illustrates a further group of possible addressees of one of the destination nodes according to the present invention; and

Figure 10B illustrates one possible way of addressing the addressee group of Figure 10A.