Method and device for determining a routing-metric
View Patent ↗The invention relates to a method and a device for which, for determining a routing-metric for a mesh-network, in particular according to standard IEEE 802.11s, routing messages sent in wireless mesh networks or mobile ad-hoc-networks, on various paths of source nodes, via the mesh nodes of the mesh networks to the target nodes, are evaluated in order to determine the best path for transferring data packets from source nodes to target nodes. Said nodes are battery-operated and mesh nodes are only used in the energy-saving mode as intermediate nodes of a path when this can not be prevented due to necessary connectivity in the mesh network or due to predetermined guidelines. Also, in each routing message sent from source nodes to target nodes via various paths, a plurality of bits, preferably two bits, are used for the number of mesh nodes operating in the path in the energy-saving mode or are battery-operated when the remaining bits of the routing-message are used for the path metric.
1. A method for determining a route for sending a message in a mesh network, comprising:
interpreting routing messages sent by a source node along various paths through a plurality of mesh nodes of the mesh network to a target node to determine a best path for sending data packets from the source node to the target node, wherein in each routing message sent from the source node through various paths to the target node, a parameter p with a number of bits indicates a number of mesh nodes in a path that are operating in a state selected from the group consisting of energy-saving mode and battery-operated mode, and wherein remaining bits of the routing message comprise a metric field that identifies a path metric that identifies a hop count for a path along which that routing message passed;
each mesh node that receives one of the routing messages that is one of battery operated and operated in energy-saving mode, increasing a value of parameter p by a predetermined value when the path metric is updated by that node unless parameter p has already reached a maximum value for parameter p; and
selecting the best path between the source node and target node based on at least one predetermined selection rule that takes into account information about how many battery-operated mesh nodes is located in each of the available paths between the source node and the target node;
wherein a number of bits for the parameter p that indicates the number of mesh nodes in the path that are operating in a state selected from the group consisting of energy-saving mode and battery-operated mode is at least two bits and is within a thirty-two bit metric field of the routing message that is used for the path metric, a portion of the metric field that does not include the parameter p being a number of bits that is equal to thirty-two bits minus a size in bits of parameter p.
2. The method of claim 1 wherein the number of bits for the parameter p that indicates the number of mesh nodes in the path that are operating in a state selected from the group consisting of energy-saving mode and battery-operated mode is two bits.
3. The method of claim 1 wherein the number of bits for the parameter p that indicates the number of mesh nodes in the path that are operating in a state selected from the group consisting of energy-saving mode and battery-operated mode is at least two bits.
4. The method of claim 1 wherein the selecting of the best path occurs based on the value of parameter p such that the best path has a fewest hops and that has a path metric that lies within a preset threshold value when a number of mesh nodes that are one of battery-operated and in energy-saving mode is the same for each of the paths.
5. The method of claim 1 wherein only paths that do not have any mesh nodes that are one of battery-operated and operating in energy-saving mode are selectable as the best path based on the value of parameter p.
6. The method of claim 1 wherein only paths with the best path metric are selectable.
7. The method of claim 1 wherein the path with fewest mesh nodes that are one of battery-operated and in energy-saving mode is selected as the best path based on the value of parameter p.
8. The method of claim 1 wherein each mesh node that is one of battery-operated and operating in energy-saving mode adding a preset penalty value ps to the path metric value when increasing the value of parameter p.
9. The method of claim 1 wherein the best path is selected from among all paths with a path metric that is better than or equal to a path metric threshold value, the path with fewest mesh nodes that are one of battery-operated and operating in energy-saving mode being the best path.
10. The method of claim 1 wherein the path with fewest mesh nodes that are one of battery-operated and operating in energy-saving mode is selected as the best path from among all paths with an average link metric value that is calculated from the path metric value divided by the number of hops and is better than or equal to a preset link metric threshold value.
11. The method of claim 10 wherein the number of bits for the parameter p that indicates the number of mesh nodes in the path that are operating in a state selected from the group consisting of energy-saving mode and battery-operated mode is two bits or at least two bits.
12. The method of 1 wherein the selecting of the best path is based on two or more predetermined rules.
13. A mesh network configured for establishing a routing metric wherein a source node sends routing messages on various paths via mesh nodes of the mesh network to a target node to be interpreted to determine a best path for sending data packets from the source node to the target node, the network comprising:
the target node;
the source node;
a plurality of mesh nodes connected to each other, the mesh nodes communicatively connecting the source node to the target node via a plurality of different paths;
the target node interpreting routing messages sent via various paths from the source node through the mesh nodes to the target node to determine the best path for sending data packets from the source node to the target node, wherein in each routing message sent from the source node through the various paths to the target node, a parameter p with a number of bits indicates a number of mesh nodes in a path that are operating in a state selected from the group consisting of energy-saving mode and battery-operated mode, and wherein remaining bits of the routing message comprise a metric field that shows a path metric that identifies a hop count for a path along which that routing message passed;
each of the mesh nodes that receives one of the routing messages that is one of battery operated and operated in energy-saving mode, increasing a value of parameter p by a predetermined value when the path metric is updated by that node unless parameter p has already reached a maximum value for parameter p; and
the target node selecting the best path between the source node and target node based on at least one predetermined selection rule that takes into account information about how many battery-operated mesh nodes is located in each of the available paths between the source node and the target node;
wherein a number of bits for the parameter p that indicates the number of mesh nodes in the path that are operating in a state selected from the group consisting of energy-saving mode and battery-operated mode is at least two bits and is within the metric field, the metric field having a size of thirty-two bits, the metric field of the routing message being used for the path metric, a remaining portion of the metric field that does not include the parameter p being a number of bits that is equal to thirty-two bits minus a size in bits of parameter p.
14. The network of claim 13 wherein the number of bits for the parameter p that indicates the number of mesh nodes in the path that are operating in a state selected from the group consisting of energy-saving mode and battery-operated mode is two bits.
15. The network of claim 13 wherein the selecting of the best path occurs based on the value of parameter p such the best path has a fewest hops and that has a path metric that lies within a preset threshold value when a number of mesh nodes that are one of battery-operated and in energy-saving mode is the same for each of the paths.
16. The network of claim 13 wherein only paths that do not have any mesh nodes that are one of battery-operated and operating in energy-saving mode are selectable as the best path.
17. The network of claim 13 wherein the path with fewest mesh nodes that are one of battery-operated and in energy-saving mode is selected as the best path.
18. The network of claim 13 wherein the best path is selected from among all paths with a path metric that is better than or equal to a path metric threshold value, the path with fewest mesh nodes that are one of battery-operated and operating in energy-saving mode being the best path.
19. The network of claim 13 wherein the path with fewest mesh nodes that are one of battery-operated and operating in energy-saving mode is selected as the best path from among all paths with an average link metric value that is calculated from the path metric value divided by the number of hops and is better than or equal to a preset link metric threshold value.