WO2008131706A1

WO2008131706A1 - Allocation of nodes of a radio network to gateways

Info

Publication number: WO2008131706A1
Application number: PCT/DE2007/000778
Authority: WO
Inventors: Markus Erlmann; Hendrik Gerlach; Christian Hock; Frank Volkmann
Original assignee: Siemens Aktiengesellschaft
Priority date: 2007-04-30
Filing date: 2007-04-30
Publication date: 2008-11-06
Also published as: DE112007003591A5

Abstract

The invention relates to a method for allocating nodes of a radio network to gateways by way of which the nodes are connected to a network. Upon startup, each node registers with a gateway located within radio range. When connecting to a network using gateways, in order to allocate nodes of a radio network to the gateways automatically such that a redundancy present in the radio network remains in the whole system, the invention provides for each node to transmit node-specific information when registering. Furthermore, each gateway receives information about which gateways are in close proximity to said nodes for at least the nodes registered with said gateway. Each gateway uses the node-specific information to determine whether redundant nodes are registered with said gateway. If redundantly registered nodes are present, the determination is made regarding which of the redundant node(s) are or will be associated with another gateway using the information from the gateways in close proximity to the associated nodes. The node(s) thus identified are registered with the corresponding gateway or gateways.

Description

description

ASSIGNING KNOTS OF A RADIO NETWORK TO GATEWAYS

The invention relates to a method for assigning nodes of a punk network to gateways, via which the nodes are connected to a network, wherein each node logs on to a gateway located within radio range when it is started up.

The invention further relates to a node of a radio network which can be connected to a network via a gateway, a gateway of a network to which a node of a radio network can be connected, and a system comprising at least one network having at least one gateway and at least one radio network having at least a node, wherein the node is connectable to the network via the gateway.

Such a method is used where elements such as in particular sensors and actuators are wirelessly connected via gateways to a network. Such sensor-actuator wireless networks are also becoming increasingly important in automation technology today, and it can be assumed that they will be used even more frequently in the future, particularly in automation technology.

The elements ("nodes", eg sensors or actuators) of a radio network (such as the wireless sensor-actuator networks mentioned above) are connected via gateways to the infrastructure (a network). It can be manually determined which node is assigned to which gateway, ie via which gateway a sensor or actuator node communicates with the infrastructure. This assignment of the sensor / actuator nodes to a gateway (= grouping) has so far taken place by means of a configuration information to be created manually. Based on the grouping, the sensor / actuator nodes are integrated into the infrastructure so that they can be used at the communi- cation. The more such nodes are used, the more time-consuming and error-prone the process of creating the configuration becomes.

This manual assignment is optional; if no such assignment is made, it happens more or less randomly. An automatic mechanism known from the WLAN field is the grouping based on the reception field strength, that is, a sensor / actuator node would look for the gateway to which it has the best radio contact. This gives no predictable results if equivalent reception ratios are present: then the grouping is more or less random. In addition, such a procedure involves the risk that individual gateways must operate disproportionately many sensor / actuator nodes, whereas other gateways are hardly used for communication. However, this danger can be circumvented by mechanisms of the prior art.

So far, aspects such as redundancy or availability, which are of particular importance for automation technology, are not taken into consideration in all known methods. Although mechanisms are known in the art for implementing redundancy for access points (e.g., the LANCOM Systems XAP-40-2), they do not solve it

Problem of redundant configuration of complete sensor / actuator networks or network parts. For such a redundant configuration, it is necessary that redundant nodes (sensors or actuators) are connected to the infrastructure via different gateways, since otherwise, even if only one gateway fails, the connection to the redundant nodes can be lost, i. the existing redundancy can not be used.

The invention is based on the object nodes of a radio network for connection to a network with gateways automa- table to assign the gateways such that a existing redundancy in the radio network in the overall system is maintained.

This object is achieved by a method of the type mentioned in that

each node transmits node-specific information during the registration,

each gateway receives information, at least via the nodes registered with it, which gateways are within reach of these nodes,

each gateway determines, by means of the node-specific information, whether redundant nodes are registered with it,

in the case of redundantly registered nodes, it is determined on the basis of the information about the gateways within reach of the relevant nodes which or which of the redundant nodes is or will be assigned to another gateway, and

- the node (s) destined or designated for this purpose are registered with the gateway (s) or gateway (s).

The object is further achieved by a node, a gateway and a system having the features specified in claims 10, 12 and 13, respectively.

The nodes are grouped automatically, not by configuration or due to the reception field strength, but on the basis of (node-specific) information, which is supplied by the respective node (typically sensor or actuator). The grouping can be considered as a kind of route selection. The inventive method is not limited to two gateways or two redundant nodes, but can also be applied to complex systems with multi-redundant nodes. As a result of the regrouping, the redundant nodes-if there are still further gateways within radio range-are distributed to different gateways, so that the redundancy of nodes, ie of sensors and / or actuators, can also be used in the overall system. The method is basically also suitable for wired "gateways". Gateways can then be switches or routers in this context.

In an advantageous embodiment of the invention, as at least part of the node-specific information, a designation with a nomenclature that identifies redundant nodes is transmitted by at least one node. This designation may e.g. be a measuring point / measured value information. A sensor thus provides, for example, information about the measuring point, e.g. a resource identifier. The nomenclature of the measuring point designation is designed in such a way that redundancy can be identified (eg rule-based). For example, two redundant pressure sensors that provide the same measurements have the designations B00050-1 and B00050-2. These equipment labels can be brought into the nodes during installation, for example.

In a further advantageous embodiment, as at least part of the node-specific information, a location information is transmitted from at least one node. As a result, information about the installation location is thus delivered. It is assumed that redundant sensors provide the same location information.

In a further advantageous embodiment, the location information is thereby obtained from the at least one node. As a result, the installation site does not have to be entered into the node by a project engineer, but is itself determined by the node, for example using GPS or radio direction finding.

In a further advantageous embodiment, as at least part of the node-specific information, an identifier for identifying the type of node is transmitted by at least one node. Especially in systems where For example, only one temperature value to be determined, this information is sufficient to detect redundant temperature sensors.

It is particularly advantageous if the node-specific information contains different information, for example location information in conjunction with an indication of the measured value type. This makes it possible to operate several different sensor types at the same location, assuming that two sensors having the same location information are redundant if they have the same type of measurement (e.g., two pressure sensors).

In a further advantageous embodiment, each gateway registers which nodes are within its radio range and receives the information as to which other gateways are within range of the nodes registered with it from the respective other gateways. Thus, a coordination between the gateways takes place in order to coordinate the regrouping of redundant nodes. This is achieved by the fact that the gateways in the commissioning phase (of a node or a gateway, but also of a subnetwork or the entire automation system) coordinate with each other and thus determine which gateway feels responsible for which node.

In a further advantageous embodiment, at least one node transmits the information about which other gateways are in its radio range when logging on to a gateway. In simple cases, it may even be possible for the respective gateway alone (i.e., without coordination with other gateways) to decide to reorder the node.

In a further advantageous embodiment, the assignment of at least one redundant node of a gateway to another in the radio range of the relevant node takes place in that the corresponding gateway requests the at least one redundant node to log in to the other gateway.

In a further advantageous embodiment, each gateway receives information from other gateways about the number of nodes registered at the respective gateway, and at least one node of the gateway is allocated to another gateway located within its radio range in order to reduce the unequal distribution. As a result, the method according to the invention also makes it possible to include aspects of the load distribution as well.

In the following the invention will be described and explained in more detail with reference to the embodiments illustrated in the figures. Show it:

1 shows two gateways of a network to which four nodes are assigned,

2 shows an inventive assignment of the nodes of Figure 1 to the gateways.

1 shows two gateways 1, 2, which are connected to each other via a network 3 (via cable or wireless). On the same network 3 there are, for example, control devices such as CPUs or PLCs which are consumers or producers of the information from or to the nodes K1, K2, K2 ', K3. The nodes K1, K2, K2 ', K3 (eg sensor or actuator nodes) are located in the radio field areas 4, 5 of the gateways 1, 2 and have different reception field strengths of these. In this case, the node Kl is located only in the radio field area 4 of the gateway 1, node K3 only in the radio field area 5 of the gateway 2, and the nodes K2, K2 'are within radio range 4, 5 of the two gateways 1, 2 (represented by the broken arrows). It is assumed here that K2 and K2 'are eg sensor nodes which deliver the same or comparable measured values (redundant sensors). During commissioning (of the network or even of individual components), the nodes K1, K2, K2 ', K3 must report to the gateways 1, 2 and must be integrated into the network. The aim here is to use the sensor redundancy and to guide it via the independent gateways 1, 2 without the need for a configuration.

If the nodes K1, K2, K2 ', K3 register at the gateways 1, 2, the following assignment (grouping), for example, first results: K1, K2, K2' at gateway 1, K3 at gateway 2. Such an assignment could eg result if the registration of the nodes Kl, K2, K2 ', K3 happens at the gateways 1, 2 only due to the reception field strength. In this case, the assignment is almost random at almost the same reception field strength; in the example shown in the figure, node K2 '- although physically closer to gateway 2 - would be more in the radio field area 4 of gateway 1 than that of gateway 2 (corresponding to a larger reception field strength), so that the above-mentioned grouping would result.

However, this grouping is unfavorable in terms of availability. If Gateway 1 fails, the connection to K2 and K2 'is lost, i. the existing redundancy of K2 and K2 'can not be used. This not only applies to sensors but also to actuators in the same way: the sub-process assigned to K2 and K2 'can then no longer be controlled. In addition, this grouping is also unfavorable for an effective load distribution, since gateway 1 has to supply three nodes K1, K2, K2 ', whereas gateway 2 only has one node K3.

FIG. 2 shows the nodes K1 ₇ K2, K2 ', K3 and gateways 1, 2 of the network 3 from FIG. 1 with a desired configuration achieved by the method according to the invention, in which the nodes K1, K2 via gateway 1 and the nodes K2' , K3 are connected via gateway 2 to the network 3. In this configuration, not only is the load distribution at the garage teways 1, 2, and in particular the primary task has been solved to obtain the redundancy present in the nodes K2, K2 'for the entire network in that they are now connected to the network 3 via different gateways 1, 2.

For the method according to the invention, information is used which originates from the nodes K1, K2, K2 ', K3 itself. This can in the exemplary case of two redundant pressure sensors K2, K2 •. The first pressure sensor K2 supplies, for example, the device identifier B00050-1, the second, redundant pressure sensor K2 'B00050-2. If the nodes K1, K2, K2 ', K3 register with the gateways 1, 2, they also transmit this node-specific information. Based on this, the two gateways 1, 2 can vote in the commissioning phase and thus determine which gateway 1, 2 feels responsible for which node Kl, K2, K2 ', K3.

Advantageously, the nodes K1, K2, K2 ', K3 already provide information on logging in at the gateways 1, 2 with which alternative gateways 1, 2 (that is to say those with sufficiently good radio communication) know them. In this case, it is even possible that the respective gateway 1, 2 itself (that is, without coordination with other gateways) can decide to "reorder" a redundant node. Example:

- The nodes K2, K2 'report when logging in at Gateway 1, that they can also work through Gateway 2.

Gateway 1 then determines that K2 and K2 'are redundant.

Gateway 1 notes that both know the alternative gateway 2. Gateway 1 initiates the regrouping of K2 '.

The regrouping can take place, for example, in that the gateway 1 requests the node K 2 'to tive gateway 2. If gateway 1 now fails, the associated measured value can also be obtained via K2 'and Gateway 2, for example.

The method according to the invention is not limited to two gateways or two nodes and in principle also suitable for wired "gateways". "Gateways" can then be switches or routers in this context. In addition, the method can be designed in such a way that aspects of the load distribution are included, thus resulting in the most uniform possible use of the resources (gateways).

In summary, the invention relates to a method for the assignment of nodes of a radio network to gateways, via which the nodes are connected to a network, each node logs on its commissioning at a gateway within radio range. In order to automatically assign nodes of a radio network for connection to a network with gateways to the gateways such that a redundancy existing in the radio network is maintained in the overall system, it is proposed in a method of the type mentioned that

each node transmits node-specific information during the log-on, each gateway receives information about which nodes are within range of these nodes, at least via the nodes registered with it,

each gateway by means of the node-specific information determines whether redundant nodes are logged in with it, in the presence of redundantly registered nodes is determined based on the information about the gateways within reach of the node in question, which or which of the redundant nodes is assigned to another gateway or and - the node (s) destined or designated for this purpose are registered with the gateway (s) or gateways (s).

Claims

claims

1. A method for assigning nodes (Kl, K2, K2 ', K3) of a radio network to gateways (1, 2), via which the nodes (Kl, K2 ₇ K2', K3) are connected to a network (3), wherein each node (Kl, K2, K2 ', K3) at its commissioning at a radio range (4, 5) located gateway (1, 2) logs, characterized in that - each node (Kl, K2, K2', K3 ) transmits node-specific information during the registration,

- Each gateway (1, 2) receives information about at least the node (Kl, K2, K2 ', K3) registered with it, which gateways (1, 2) are within reach (4, 5) of these nodes (Kl, K2, K2 •, K3),

each gateway (1, 2) determines by means of the node-specific information whether redundant nodes (K2, K2 ') are registered with it,

- In the presence of redundantly registered nodes (K2, K2 ') based on the information about the gateways (1, 2) in range (4, 5) of the respective node (K2, K2') is determined which or which of the redundant nodes ( K2, K2 ') is or will be assigned to another gateway (1, 2), and - the node or nodes (K2, K2') destined for or destined for this are registered with the gateway or gateways (1, 2).

2. The method of claim 1, wherein as at least a part of the node-specific information is a designation with a nomenclature, the redundant nodes (K2, K2 '), at least one node (Kl, K2, K2', K3) is transmitted.

3. The method of claim 1 or 2, wherein as at least part of the node-specific information, a location information of at least one node (Kl, K2, K2 ', K3) is transmitted.

4. The method of claim 3, wherein the location information is obtained from the at least one node (Kl, K2, K2 ', K3).

5. The method according to any one of the preceding claims, wherein as at least a part of the node-specific information, an identifier for identifying the node type of at least one node (Kl, K2, K2 ', K3) is transmitted.

6. Method according to one of the preceding claims, wherein each gateway (1, 2) registers which nodes (Kl, K2, K2 ', K3) are in its radio range (4, 5) and the information which other gateways ( 1, 2) are in range (4, 5) of the nodes registered with him (Kl, K2, K2 ', K3), from the other gateways (1, 2) receives.

7. The method according to any one of the preceding claims, wherein at least one node (Kl, K2, K2 ', K3) when logging on to a gateway (1, 2) the information which other gateways (1, 2) in its radio range ( 4, 5), mitüberträgt.

8. The method according to any one of the preceding claims, wherein the assignment of at least one redundant node (K2 ') of a gateway (1) to another within radio range (4, 5) of the node (K2') located gateway (2) thereby takes place, the corresponding gateway (1) requests the at least one redundant node (K2 ') to log on to the other gateway (2).

9. The method according to any one of the preceding claims, wherein each gateway (1, 2) of other gateways (1, 2) information about the number of the respective gateway (1,

2) registered node (Kl, K2, K2 ^■ , K3) receives and at a predeterminable unequal distribution at least one node (Kl, K2, K2 ', K3) of the gateway (1, 2) to reduce the unequal distribution another in its radio range (4, 5) located gateway (1, 2) is assigned.

10. Node (Kl, K2, K2 ', K3) of a radio network, which is connectable via a gateway (1, 2) to a network (3), characterized in that the node (Kl, K2, K2', K3) means for carrying out a method according to one of claims 1 to 9.

11. A node according to claim 10, wherein the node (Kl, K2, K2 ', K3) is a sensor or actuator.

12. Gateway (1, 2) of a network (3) to which a node (Kl, K2, K2 ', K3) of a radio network can be connected, characterized in that the gateway (1, 2) means for performing a method according to a of claims 1 to 9.

13. System comprising at least one network (3) with at least one gateway (1, 2) and at least one radio network with at least one node (Kl, K2, K2 ', K3), wherein the node (Kl, K2, K2', K3 ) is connectable to the network (3) via the gateway (1, 2), characterized in that the system comprises at least one node (Kl, K2, K2 ', K3) according to claim 10 or 11 and at least one gateway (1, 2) according to claim 12.