METHOD FOR ESTABLISHING A MULTIPATH COMMUNICATION WITH MAXIMIZED AVAILABILITY

Abstract

A method for establishing a communication through multiple distinct communication paths deployed over different network operators includes collecting location information of network nodes of available distinct paths between a source node and destination node, comparing location information of the network nodes to identify possibly co-located network nodes, determining path segment lengths of consecutive path segments between the nodes of each path, estimating whether path segments of the paths intersect based on locations of the network nodes and the path segment lengths, selecting multiple paths that do not include intersecting path segments and/or co-located network nodes, and establishing communication between the source node and destination node over both selected paths.

Claims

1. A method for establishing a communication through multiple distinct communication paths deployed over different network operators, comprising: collecting location information of network nodes of several available distinct paths between a source node and a destination node; comparing location information of the network nodes to identify possibly co-located network nodes; determining path segment lengths of consecutive path segments between the nodes of each path; estimating whether path segments of the paths intersect based on locations of the network nodes and the path segment lengths; selecting multiple paths that do not comprise intersecting path segments and or co-located network nodes and or co-sharing path segments; and establishing communication between the source node and the destination node over both selected paths.

2. The method according to claim 1, wherein the collecting of location information of network nodes comprises querying respective nodes for location information.

3. The method according to claim 1, wherein the determining of path segment lengths comprises measuring a transmission delay along a respective path segment.

4. The method according to claim 1, wherein the determining of path segment lengths comprises calculating a distance between consecutive nodes of respective path segments.

5. The method according to claim 3, wherein the determining of path segment lengths comprises calculating a distance between consecutive nodes of respective path segments; and further comprising: calculating a ratio of a sum of distances between a common node and multiple connected, distanced nodes and a sum of respective path segment lengths, wherein the path segments are non-sharing if the ratio is greater than 0.85 to 0.95 or greater than 0.9.

6. The method according to claim 1, wherein the selecting of multiple paths additionally comprises determining a total path length and or expected signal attenuation and or signal latency as a cost factor for each available path and minimizing the cost factor when selecting the multiple paths.

7. A system for establishing communication through multiple distinct communication paths deployed over different network operators, comprising a start node and a destination node, wherein each of the start node and the destination node comprises at least one communication device configured for establishing communication between the source node and the destination node over multiple paths, wherein each of the start node and the destination node comprises a control unit, wherein at least one of the control units is configured for: collecting location information of network nodes of several available distinct paths between the source node and the destination node; comparing location information of the network nodes to identify possibly co-located network nodes; determining path segment lengths of consecutive path segments between the nodes of each path; estimating whether path segments of the paths intersect based on locations of the network nodes and the path segment lengths; and selecting multiple paths, through which the communication is to be established, that do not comprise intersecting path segments and or co-located network nodes and or co-sharing path segments.

8. The system according to claim 7, wherein the collecting of location information of network nodes comprises querying respective nodes for location information through the at least one control unit.

9. The system according to claim 7, wherein the determining of path segment lengths comprises measuring a transmission delay along a respective path segment through the at least one control unit.

10. The system according to claim 7, wherein the determining of path segment lengths comprises calculating a distance between consecutive nodes of the respective path segments through the at least one control unit.

11. The system according to claim 9, wherein the at least one control unit is further configured for calculating a ratio of a sum of distances between a common node and multiple connected, distanced nodes and a sum of respective path segment lengths, wherein the path segments are non-sharing if the ratio is greater than 0.85 to 0.95 or greater than 0.9.

12. The system according to claim 7, wherein the selecting of multiple paths additionally comprises determining a total path length and or expected signal attenuation and or signal latency as a cost factor for each available path and minimizing the cost factor when selecting the multiple paths.

13. A vehicle system comprising at least one vehicle, at least one communication station and at least one system according to claim 7, wherein the start node is arranged in one of the vehicle and the communication station, and wherein the destination node is arranged another of the vehicle and the communication station.

14. The vehicle system according to claim 13, wherein the vehicle is an aircraft, and wherein the communication station is a ground station.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the following, the attached drawings are used to illustrate example embodiments in more detail. The illustrations are schematic and not to scale. Identical reference numerals refer to identical or similar elements.

[0032] FIG. 1 shows a schematic, block-oriented view of a method for establishing a communication.

[0033] FIG. 2 shows two communication paths with several nodes.

[0034] FIG. 3 shows a vehicle system having a vehicle, a ground station, base stations, and a system for establishing a communication.

[0035] FIGS. 4a, 4b and 4c show different scenarios of adjacent communication paths.

[0036] FIG. 5a shows an example of several communication paths with a potential co-shared segments.

[0037] FIG. 5b shows an example of two communication paths connected to the same destination node for estimation of co-sharing.

DETAILED DESCRIPTION

[0038] FIG. 1 shows a schematic, block-oriented illustration of a method 2 for establishing a communication through multiple distinct communication paths deployed over different network operators. It is noted that in the presented examples two communication paths are selected for clearer and easier explanation. However, the method and system according to the disclosure herein also apply to multiple paths.

[0039] The method 2 comprises the steps of collecting 4 of location information of network nodes of several available distinct paths between a source node and a destination node, comparing 6 location information of the network nodes to identify possibly co-located network nodes, determining 8 of path segment lengths of consecutive path segments between the nodes of each path, estimating 10 whether path segments of the paths intersect based on the locations of the network nodes and the path segment lengths, selecting 12 of multiple paths that do not comprise intersecting path segments and/or co-located network nodes and/or co-sharing path segments, and establishing 14 a communication between the source node and the destination node over both selected paths.

[0040] The collecting 4 of location information of network nodes may comprise querying 16 the respective nodes for location information. The determining 8 of path segment lengths may comprise measuring 18 a transmission delay along the respective path segment and/or calculating 20 a distance between consecutive nodes of the respective path segments.

[0041] In addition, the method may further comprise calculating 22 a ratio of the sum of distances between a common node and multiple connected, distanced nodes and the sum of respective path segment lengths, wherein it is assumed that the path segments are non-sharing if the ratio is greater than 0.85 to 0.95 and in particular greater than 0.9. This may be conducted in the step of selecting 12 multiple paths. Also, the selecting 12 of multiple paths may additionally comprise determining 24 a total path length and/or expected signal attenuation and/or signal latency as a cost factor for each available path and minimizing 26 the cost factor when selecting the multiple paths.

[0042] FIG. 2 demonstrates the availability of communication paths in an example, where two communication paths 28 and 30 between a source node 32 and a destination node 34 are shown. The first path 28 comprises two path segments 28a and 28b. The second path 30 comprises three path segments 30a, 30b and 30c. While the first path 28 comprises one intermediate node 29, the second path comprises two intermediate nodes 31a and 31b.

[0043] The availability of the communication from the source node 32 to the destination node 34 is calculated based on availability values of the subsystems or components that compose the respective paths 28 and 30. In this example, data is transported from the source node 32 to the destination node 34 over the two disjoint paths 28 and 30. Assuming that the node availability is 1, i.e. 100%, the overall service availability A is calculated as follows:

A=1−(1−A.sub.28).Math.(1−A.sub.30)=A.sub.28+A.sub.30−A.sub.28.Math.A.sub.30

wherein where A.sub.28=A.sub.28a.Math.A.sub.28b and A.sub.30=A.sub.30a.Math.A.sub.30b.Math.A.sub.30c. The subscript numbers indicate the respective paths or path segments.

[0044] For simplicity, the path segments 28a, 28b, 30a, 30b, 30c are assumed to have the same availability of 0.999. The total end-to-end service availability when transferring information from the source node 32 to the destination node 34 simultaneously on both communication paths 28 and 30 is 0.99999. For the same network shown in FIG. 1, if segment path 28b and segment path 30c share the same risk, such that a single failure would result in both links 28b and 30c failing simultaneously, the end-to-end service availability is calculated as follows:

A=(1−(1−A.sub.28a).Math.(1−A.sub.30a.Math.A.sub.30b)).Math.A.sub.28b/30c

[0045] If using the same common path segment availability of 0.999 for every path segment, the service end-to-end availability is 0.9989, which is two orders of magnitude lower compared to the case, when the path segments are not affected by the same risk. This shows the importance of identifying common risks, when provisioning high availability services.

[0046] FIG. 3 shows a vehicle system 36 with a vehicle 38 exemplarily in form of a helicopter, a communication station 40 and a system 41 for establishing a communication between the vehicle 38 and the communication station 40. In this example, two base stations 42 and 44 are available, wherein it is assumed that the first base station 42 provides communication services for two network operators and that the second base station 44 only provides communication services for only one of the network operators. Hence, three different communication paths 46, 48 and 50 are available. According to the method described in combination with FIG. 1, two of the paths 46, 48 and 50 are to be selected.

[0047] The vehicle 38 uses a direct air to ground (DA2G) communication service deployed using dual-connectivity, via both network operators towards the communication station 40, which may be referred to as a base station, a ground assistant, remote pilot station or air traffic control.

[0048] If both communication paths from the vehicle 38 to the communication station run through the first base station 42, the service can be affected if a failure happens at the shared resource of the first base station 42, e.g. power outage. Thus, to guarantee the high availability of the service, this shared risk should be identified and only the first communication path 46, operated by a first operator OP1, and the third communication path 50, operated by a second operator OP2, should be used. As mentioned in combination with FIG. 1, both base stations 42 may be equipped with network functions 52 for each operator OP1 and OP2, wherein a control unit 54 in the communication station 40 or a control unit 56 inside the vehicle 38 is able to query for information and to conduct several tasks required for the method according to the disclosure herein. The network functions 52 may exemplarily be able to communicate with a GPS module 58 for retrieving location information.

[0049] In FIGS. 4a, 4b and 4c two path segments 60 and 62 are shown that extend between a first node 64 and a second node 66 as well as between a third node 68 and a fourth node 70. When conducting the method according to FIG. 1 it can be determined by the step of collecting 4 of location information that all four nodes 64 to 70 are distinct nodes. Furthermore, the physical path segment lengths can be estimated, e.g. through providing a propagation delay measurement. By this, it can be determined whether the path segments 60 and 62 are most likely diverse (FIG. 4a), or may or may not be diverse (FIGS. 4a and 4b). For example, if the lengths of the path segments 60 and 62 are almost identical to the distances of the respective nodes 64 and 66 or 68 and 70, the path segments 60 and 62 are most probably diverse, as shown in FIG. 4a. Due to extended lengths of the path segments 60 and 62 in FIGS. 4b and 4c a reliable estimation is almost impossible without further knowledge of the course of the path segments 60 and 62. For example, in the illustration of FIG. 4b an intersection region 72 between the two path segments 60 and 62 exists. Here, both path segments 60 and 62 may share the same line duct, tunnel, bridge, or any other structural feature, wherein a single failure in this intersection region 72 may lead to damages to both path segments 60 and 62. Consequently, suitable communication paths can be chosen by selecting node pairs that are surely diverse to improve the availability.

[0050] FIG. 5a demonstrates a more complex arrangement of nodes 74, 76, 78, 80 and 82 between the start node 32 and the destination node 34, wherein a plurality of path segments 84, 86, 88, 90, 92, 94, 96 and 98 are created. Several distinct paths are possible. A general approach for maximizing the availability lies in creating a binary matrix, in which all path segments 84-98 are evaluated. In addition, a cost function optimization is provided, wherein cost values are indicated with numbers next to the path segments 84-98 in FIG. 5a.

[0051] A suitable binary matrix for evaluating the path segments may be as follows, wherein the value “1” stands for non-sharing path segment and “0” for all other states. The path segments 92 and 94 are not clearly distinct, such that a “0” is entered for the combinations of path segments 92 and 94. However, all other path segments 84-90 and 96-98 are likely non-sharing.

TABLE-US-00001 path segment 84 86 88 90 92 94 96 98 84 — 1 1 1 1 1 1 1 86 1 — 1 1 1 1 1 1 88 1 1 — 1 1 1 1 1 90 1 1 1 — 1 1 1 1 92 1 1 1 1 — 0 1 1 94 1 1 1 1 0 — 1 1 96 1 1 1 1 1 1 — 1 98 1 1 1 1 1 1 1 —
The source node 32 and the destination node 34 have to be connected with two distinct paths to increase the availability. If an objective function with cost minimization without constraints is used, i.e. without excluding possibly shared path segments, a first path, i.e. a working path, will be a path running from the start node 32 to node 78 through segment path 88, afterwards to node 82 through the path segment 94 as well as to the destination node 34 through path segment 98, with a cost value of “60”. A protection path would result in a path running from the start node 32 to node 76 through segment path 86, afterwards to node 80 through the path segment 92 as well as to the destination node 34 through path segment 96, with a cost value of “70”.

[0052] However, if the same objective function is used, but the constraint is added to avoid shared path segments, the working path will be start node 32-node 78-node 82-destination node 34 with a cost value of “60”. The protection path would be start node 32-node 74-destination node 34 with a cost value of “100”.

[0053] Still further, regarding the estimation stated in connection with FIG. 4a, i.e. that the path segments are most probably diverse if the lengths of path segments are almost identical to the distances of the respective nodes, it is further pointed to FIG. 5b. Here, a first node 100 and a second node 102 together with the destination node 34 are shown. A first path segment 104 having a first path length I1 extends from the first node 100 to the destination node 34. A second path segment 106 having a second path length I2 extends from the second node 102 to the destination node 34. The first node 100 is distanced from the second node 102. A first distance d1 refers to the distance between the first node 100 and the destination node 34. A second distance d2 refers to the distance between the second node 102 and the destination node 34. If

[00002]$\frac{d_1+d_2}{l_1+l_2}>0,9,$

i.e. if the sum of path segment lengths are almost identical to the sum of node distances, it may be assumed that the first and second path segments 104 and 106 are diverse. As explained above, this assumption may apply to a ratio greater than 0.85 to 0.95 and in particular greater than 0.9.

[0054] While at least one example embodiment of the invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

REFERENCE NUMERALS

[0055] 2 method [0056] 4 collecting location information [0057] 6 comparing location information [0058] 8 determining path segment lengths [0059] 10 estimating path segments intersecting [0060] 12 selecting multiple paths [0061] 14 establishing communication [0062] 16 querying for location information [0063] 18 measuring a transmission delay [0064] 20 calculating a distance [0065] 22 calculating a ratio [0066] 24 determining local path length/attenuation/latency [0067] 26 minimizing cost factor [0068] 28 communication path [0069] 28a, 28b path segments [0070] 29 intermediate node [0071] 30 communication path [0072] 30a, 30b, 30c path segments [0073] 31a, 31b intermediate node [0074] 32 source node [0075] 34 destination node [0076] 36 vehicle system [0077] 38 vehicle [0078] 40 communication station [0079] 41 system for establishing communication [0080] 42 first base station [0081] 44 first base station [0082] 46 communication path [0083] 48 communication path [0084] 50 communication path [0085] 52 network function [0086] 54 control unit [0087] 56 control unit [0088] 58 GPS module [0089] 60 path segment [0090] 62 path segment [0091] 64 first node [0092] 66 second node [0093] 68 third node [0094] 70 fourth node [0095] 72 intersection region [0096] 74 node [0097] 76 node [0098] 78 node [0099] 80 node [0100] 82 node [0101] 84 path segment [0102] 86 path segment [0103] 88 path segment [0104] 90 path segment [0105] 92 path segment [0106] 94 path segment [0107] 96 path segment [0108] 98 path segment [0109] 100 first node [0110] 102 second node [0111] 104 first path segment [0112] 106 second path segment [0113] OP1 First network operator [0114] OP2 second network operator [0115] d1 first distance [0116] d2 second distance [0117] I1 first path segment length [0118] I2 second path segment length