ESTABLISHING AN AD HOC COMMUNICATION NETWORK, AND PRIORITY-CONTROLLED DATA TRANSMISSION IN A RAIL VEHICLE

Abstract

A method for establishing communication and for transmitting data between sensor units in a rail vehicle uses a communication network which has multiple network nodes. An advantageous communication network and/or an advantageous data transmission can be achieved if the sensor units independently form an ad hoc network with a network topology for transmitting data in the rail vehicle, configure the network, and change the network topology over the course of the data transmission and/or if the communication network is an ad hoc network and the network nodes are sensor units. A rail vehicle including a communication network which has multiple network nodes is also provided.

Claims

1-13. (canceled)

14. A method for establishing communication and for transmitting data between sensor units in a rail vehicle, the method comprising the following steps: using the sensor units to independently form and configure an ad-hoc network having a network topology for transmitting data in the rail vehicle and to change the network topology over a course of the data transmission.

15. The method according to claim 14, which further comprises forming the ad-hoc network between sensor units being relevant for operational safety and sensor units being relevant solely for operation.

16. The method according to claim 15, which further comprises transmitting data being relevant for operational safety and data being relevant solely for operation over the ad-hoc network.

17. The method according to claim 16, wherein the data being relevant for operational safety are at least one of control data or sensor data, and the data being relevant solely for operation are at least one of seat reservation data, infotainment data or accounting data.

18. The method according to claim 16, which further comprises additionally directing the data being relevant for operational safety over a part-network topology formed by sensor units being relevant solely for operation.

19. The method according to claim 14, which further comprises linking an access point leading to a supervisory cable-based network to the ad-hoc network.

20. The method according to claim 14, which further comprises at least one of forming or configuring the network topology according to a prioritization of the sensor units.

21. The method according to claim 14, which further comprises at least one of forming or configuring the network topology as a function of a predetermined maximum propagation delay of a data transmission originating from one of the sensor units to a cab control point.

22. The method according to claim 14, which further comprises directing a warning signal over the ad-hoc network if a predetermined maximum propagation delay of a data transmission originating from one of the sensor units to a cab control point is exceeded.

23. The method according to claim 14, which further comprises directing a warning signal over the ad-hoc network being at least partially formed if a predetermined maximum time period before complete formation of the ad-hoc network is exceeded.

24. A rail vehicle, comprising: a communication network including a plurality of network nodes; said communication network being an ad-hoc network and said network nodes being sensor units.

25. The rail vehicle according to claim 24, which further comprises a bogie of the rail vehicle, at least a plurality of said sensor units being disposed in said bogie.

26. The rail vehicle according to claim 24, which further comprises: a supervisory cable-based network; and an access point to said supervisory cable-based network; said ad-hoc network being linked to said access point.

27. The rail vehicle according to claim 26, which further comprises a bogie of the rail vehicle, said access point being disposed above said bogie.

Description

[0046] FIG. 1 shows a schematic illustration of a rail vehicle having a communication network.

[0047] FIG. 1 shows a rail vehicle 2 having a communication network 4 which comprises a plurality of network nodes 6.

[0048] The communication network 4 is an ad-hoc network 8 and the network nodes 6 are sensor units 10a-j, 12a-c, 14a-e, 16a-e.

[0049] Identical features, which may nonetheless have slight differences in e.g. an amount or a numerical value, a dimension, a position and/or a function etc., are identified using the same reference numeral and a reference letter or a different reference letter. If the reference numeral alone is mentioned without a reference letter, all of the corresponding features are indicated.

[0050] A multiplicity of wireless communication connections, creating an intermeshed network topology N, are formed or set up between the sensor units 10, 12, 14 and 16. In order to allow simpler illustration, said wireless communication connections are not explicitly denoted by reference signs.

[0051] In order to allow better illustration, only a locomotive 18 of the rail vehicle 2 is illustrated, wherein the illustrated ad-hoc network 8 obviously need not be limited to the locomotive 18, but can also be set up in the rail vehicle cars (not illustrated) of the rail vehicle 2.

[0052] The locomotive 18 has two bogies 20a, 20b. The bogies 20 have wheelsets 22, the locomotive 18 being supported on a track 24 via said wheelsets 22.

[0053] The sensor units 14a-e are arranged in the bogie 20a and the sensor units 16a-e are arranged in the bogie 20b of the locomotive 18 or the rail vehicle 2. The further sensor units 12a-c and 10a-j are so arranged in the locomotive 18 or in the rail vehicle 2 as to be distributed at different locations, e.g. in a passenger compartment, on a traction system, on units, on installation engineering or similar. The sensor units 12 and 10 can generally be attached to any locations of the rail vehicle 2 for the purpose of capturing measured variables and/or operational parameters.

[0054] The sensor units 14 and 16 arranged in the bogies 20 are designed to metrologically capture vibration values of the wheelsets and/or an axle bearing temperature.

[0055] The ad-hoc network 8 is linked via a plurality of access points 26a, 26b, 26c, 26d, 26e and 26f to a supervisory cable-based network 28. In the present exemplary embodiment, the cable-based network 28 is a bus system 30 that is connected to a cab control point 32. The access points 26a, 26c, 26d and 26f are arranged in relatively close proximity to the bogies, above the sensor units 14 and 16 respectively, such that a reliable wireless link with an adequate signal strength can be achieved from the sensor units 14 and 16 to the access points 26a, 26c, 26d and 26f.

[0056] The sensor units 14a-e and 16a-e are sensor units that are relevant for operational safety, being designed for the metrological capture of measured variables or data which is relevant for operational safety.

[0057] The sensor units 12a-c and 10a-j are sensor units which are relevant solely for operation, being designed to capture operational parameters of the rail vehicle 2, e.g. a temperature of an interior environment, a seat occupancy or similar.

[0058] The network topology N of the ad-hoc network 8 is subdivided into part-network topologies N.sub.1, N.sub.2, N.sub.3 and N.sub.4. The part-network topology N.sub.1 is formed between the sensor units 14a-e that are relevant for operational safety. The part-network topology N.sub.2 is formed between the sensor units 16a-e that are relevant for operational safety. The part-network topology N.sub.3 is formed between the sensor units 12a, 12b and 12c that are relevant solely for operation. The part-network topology N.sub.4 is formed between the sensor units 10a-j that are relevant solely for operation. It is naturally also possible for a part-network topology to be formed by both sensor units which are relevant for operational safety and sensor units which are relevant solely for operation, i.e. by sensor units of different categories.

[0059] In order to establish communication and to transmit data between the sensor units 10, 12, 14 and 16 in the rail vehicle 2 and/or with the cab control point 32, the sensor units 10, 12, 14 and 16 form the ad-hoc network 8 having the network topology N independently, i.e. in particular without manual intervention from any operating personnel. In this case, the network topology N or the part-network topologies N.sub.1, N.sub.2, N.sub.3 and N.sub.4 are changed over time, in particular over the course of the data transmission and/or when communication is being established.

[0060] In order to form the network topology N and/or to establish communication within the ad-hoc network 8, following activation of the rail vehicle 2 and/or following loss of a communication connection, the sensor units 10, 12, 14 and 16 send seek signals and/or receive such seek signals from proximate sensor units. The manner in which the network topology N and/or the wireless communication channels between the sensor units 10, 12, 14 and 16 are formed may depend on a multiplicity of criteria.

[0061] In the present exemplary embodiment, the network topology N is formed and/or configured, i.e. adapted to changing conditions, changed relative to time, set up, modified, etc., according to prioritizations P.sub.1, P.sub.2, P.sub.3 and P.sub.4 of the sensor units 14, 16, 12 and 10 respectively. Specifically, the wireless communication connection or the part-network topology N.sub.1 between the sensor units 14 having the priority P.sub.1, which is comparatively the highest priority in this case, is formed first.

[0062] Following thereupon, the part-network topology N.sub.2 is formed between the sensor units 16 having the next highest prioritization P.sub.2. The part-network topology N.sub.3 is then formed between the sensor units 12a, 12b and 12c having the next highest prioritization P.sub.3, and finally the part-network topology N.sub.4 is formed between the sensor units 10a-j having the lowest prioritization P.sub.4 in this case.

[0063] The prioritizations P.sub.1, P.sub.2, P.sub.3 and P.sub.4 reflect whether the relevant sensor units capture measured variables which are relevant for operational safety or operational parameters which are relevant solely for operation of the rail vehicle 2. However, a multiplicity of further prioritizations based on further criteria are also possible.

[0064] In particular, if limited resources are available within the ad-hoc network 8 and/or within the supervisory network 28 or the bus system 30, a temporally staggered connection of the sensor units 10, 12, 14 and 16 takes place according to their prioritizations P.sub.1 to P.sub.4, such that the sensor units with highest prioritization are preferentially integrated into the ad-hoc network 8 or linked to the supervisory cable-based network 28 via the access points 26.

[0065] The data transmission between the sensor units 10, 12, 14 and 16, and from the sensor units to the cab control point 32, is effected by means of a multi-hop connection in which the data from a sensor unit is directed via one and/or a plurality of further sensor units to one of the access points 26 into the supervisory network 28 and on to the cab control point 32. In this case, a propagation delay that occurs in the data transmission originating from a sensor unit to the cab control point 32 depends essentially on a number of hops, i.e. the number of sensor units via which the data is diverted. In the present exemplary embodiment, the cab control point 32 has a storage unit 34 with a data record 36 which is stored therein and relates to a predetermined maximum propagation delay t.sub.m.

[0066] The network topology N is formed and/or configured as a function of the predetermined maximum propagation delay t.sub.m to the cab control point of a data transmission originating from one of the sensor units 10, 12, 14 and/or 16.

[0067] The network topology N here is formed and/or configured as a function of the propagation times of data transmissions originating from the sensor units that are relevant for operational safety 14 and 16. Method steps required for this purpose are explained in the following for the sensor unit 16a by way of example:

[0068] In order to form the network topology N, e.g. following an activation of the rail vehicle 2 or loss of a communication link to an individual sensor unit or multiple sensor units, the sensor unit 16a sends a seek signal S.

[0069] The seek signal S is received by the proximate sensor units 10i, 16b and 16c.

[0070] The seek signal S is fed from the proximate sensor unit 10i via the sensor unit 10j and the access point 26e into the cable-based network 28, and forwarded via the latter to the cab control point 32. The required propagation delay of the seek signal originating from sensor unit 16a is t.sub.1.

[0071] The seek signal S received by the sensor unit 16b is fed via the access point 26d into the cable-based network 28, and forwarded via the latter to the cab control point 32. In this case, the propagation delay of the seek signal is t.sub.2.

[0072] The seeks signal S received by the sensor unit 16c is fed via the sensor unit 16d and the access point 26f into the cable-based network 28, and forwarded by the latter to the cab control point 32. In this case, the propagation delay of the data transmission is t.sub.3.

[0073] The propagation times t.sub.1, t.sub.2 and t.sub.3 are compared with the permitted maximum propagation delay t.sub.m. If one of the propagation times t.sub.1, t.sub.2 and/or t.sub.3 exceeds the maximum propagation delay t.sub.m, the corresponding data transmission path giving rise to the propagation delay is rejected for a future data transmission originating from the sensor unit 16a. In this case, the data transmission paths originating from the sensor unit 16a via the sensor units 10i and 16c are rejected.

[0074] Instead, the data transmission path which allows the smallest propagation delay, here the propagation delay t.sub.2, is preferably used for future data transmissions originating from the sensor unit 16a, via the sensor unit 16b in this case. The network topology N is formed and/or configured accordingly.

[0075] Operating states of the ad-hoc network 8 are conceivable in which a data transmission having a minimal propagation time on a data transmission route originating from a sensor unit via the fewest possible further sensor units to the cab control point 32 is not readily achievable.

[0076] For example, if wireless communication is lost between the sensor units 16a and 16d and therefore measured values or data which is captured by the sensor unit 16a and is relevant for operational safety cannot be transmitted on the route having the smallest possible propagation delay, a warning signal W is directed via the ad-hoc network 8, specifically originating from the sensor unit 16a via the sensor unit 10i, the sensor unit 10j, the access point 26e and via the cable-based network 28 to the cab control point 32. A corresponding operating action can be performed by the rail vehicle driver, e.g. a reduction of the rail vehicle speed, as a function of this warning signal W.

[0077] A data record 38 relating to a maximum time period z.sub.m before complete formation of the ad-hoc network 8 is stored in the storage unit 34 of the cab control point 32. The ad-hoc network 8 can be completely formed when all required sensor units have been integrated into the network topology N and their data can be received by the cab control point. If the maximum time period z.sub.m before complete formation of the ad-hoc network 8 is exceeded, a warning signal W is directed via the at least partially formed ad-hoc network.

[0078] Each of the sensor units that are relevant for operational safety 14 and 16 captures data that is relevant for operational safety D.sub.s, wherein in order to allow simpler illustration in the present exemplary embodiment, only the data which is relevant for operational safety D.sub.s and captured by the sensor unit 14b is illustrated schematically. Each of the sensor units 12 and 10 captures data which is relevant solely for operation D.sub.b, wherein in order to allow simpler illustration, only the data D.sub.b which is relevant for operation and captured by the sensor unit 12a is illustrated schematically. Both data that is relevant for operational safety D.sub.s and data that is relevant solely for operation D.sub.b are transmitted via the ad-hoc network 8.

[0079] The data which is relevant for operational safety D.sub.s is first transmitted via the part-network topology N.sub.1, which is formed between the sensor units that are relevant for operational safety 14a-e. In addition, the data which is relevant for operational safety D.sub.s is transmitted via the communication connection between the sensor units 14b and 12a and is consequently fed into the part-network topology N.sub.3, which is formed of sensor units that are relevant solely for operation 12a, 12b and 12c. In this way, a redundant data transmission is achieved for the data that is relevant for operational safety D.sub.s, and consequently a high level of operational safety is achieved for the rail vehicle 2.