IP COMMUNICATION ARCHITECTURE BETWEEN THE GROUND AND A VEHICLE

• US 20110194541A1
• Filed: 01/16/2009
• Published: 08/11/2011
• Est. Priority Date: 01/16/2008
• Status: Active Grant

• Current Assignee: Alstom Transport SA (Alstom SA)
• Original Assignee: Alstom Transport SA (Alstom SA)
• Inventors: Ruffolo, Frank, Menaceur, Djamil-Fayçal
• Granted Patent: US 8,687,612 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 2212/00 Encapsulation of packets
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 61/2546 Arrangements for avoiding unnecessary translation
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 40/28 for reactive routing
• CPC Class Codes: H04W 84/005 Moving wireless networks

Abstract

An IP communication architecture between a ground computer connected to a main router and a mobile computer which is located on board a train and which is connected to a mobile router on the train. The architecture comprises at least one infrastructure comprising the base stations equipped with radio communication devices and base routers on the ground which are connected to the infrastructure. Each mobile router comprises:

• • a radio communication means suitable for establishing a wireless link with one of the base stations of the infrastructure,
  • storage means comprising the IP address of the base routers connected to the infrastructure, and
  • connection means for initiating a connection with a base router on the basis of the list of base routers, after a wireless link has been established.

Claims

1-20. -20. (canceled)

21. An system for IP communication between a first fixed piece of computing equipment located on the ground and connected to a first local network and a second mobile piece of computing equipment located on board one vehicle of a plurality of vehicles, each vehicle of the plurality of vehicles having a second local network, the second piece of equipment being connected to the second local network of the one vehicle on which the second piece of computing equipment is located, the system comprising:

a global tree network including;

a main router connected to the first local network;

lower-level nodes formed by a plurality of mobile routers, each vehicle of the plurality of vehicles having one mobile router of the plurality of mobile routers, the one mobile router being connected to the second local network of the one vehicle; and

intermediate nodes, the intermediate nodes being located above the lower-level nodes, the intermediate nodes including base routers, the base routers being located on the ground;

at least one communication infrastructure, each base router being connected to one of the at least one communication infrastructures and having an IP address on the one of the at least one communication infrastructures with which it is associated, each of the at least one communication infrastructures including base stations equipped with base station radio communication devices,

wherein each mobile router includes;

a mobile router radio communication device for establishing, at a given moment, a wireless link with one of the base stations of the at least one communication infrastructures,

a mobile router storage device having a list of each base router which includes the IP addresses of each base router with the associated communication infrastructures of which the mobile router radio communication device is able to establish the wireless link, and

a mobile router connection device for initiating a connection with one of the base routers from the list of each base router, after the wireless link has been established.

22. The system according to claim 21 wherein the main routers, the base routers and the mobile routers respectively include a main routing table, a base routing table and a mobile routing table and a main updating device, a base updating device and a mobile updating device for dynamically updating the main, base and mobile routing tables, each base router having a base transmitting device for transmitting a connection status message to the main router, informing the main router about the mobile routers which have just connected to or disconnected from the relevant base router.

23. The system according to claim 21 wherein the mobile router connection device for connecting one mobile router of the plurality of mobile routers includes a pre-detecting device for pre-detecting the loss of an active connection and a mobile temporary storage device for temporarily storing data to be transmitted when the quality of the active connection is reduced.

24. The system according to claim 22 wherein the base routers include a base router storage device comprising a list of new base routers, wherein the mobile router updating device updates the list of base routers based on the list of new base routers in the base router to which the mobile router connects.

25. The system according to claim 21 wherein the base routers are connected to the associated communication infrastructure in such a way that a distance between a base router and a base station of the associated infrastructure corresponds to a single link in the network.

26. The system according to claim 21 wherein the at least one communication infrastructure uses a short-range wireless communication technology.

27. The system according to claim 21 wherein the system includes a first and a second communication infrastructure of the at least one communication infrastructures in such a way that a first cell of a first base station of the first infrastructure is superposed, at least in part, in an overlap region, on a second cell of a second base station of the second infrastructure, and in that the one mobile router of the plurality of mobile routers simultaneously establishes when the one vehicle on which the mobile router is located passes through the overlap region, a first connection with a first base router via a first wireless link established with a first base station of the first infrastructure and a second connection with a second base router via a second wireless link established with a second base station of the second infrastructure

28. The system according to claim 27 wherein the main router and the one mobile router of the plurality of mobile routers respectively have a main arbitration device and a mobile arbitration device allowing a route to be selected from a first route passing through the first infrastructure and a second route passing through the second infrastructure for ongoing communication between the first piece of computing equipment and the second piece of computing equipment.

29. The system according to claim 28 wherein the first and second infrastructures are of different types, using different technologies and the one mobile routers of the first and second infrastructures include a plurality of the mobile router radio communication devices, each mobile router radio communication device establishing the wireless link with the first and second infrastructure of a same technology.

30. The system according to claim 21 wherein each vehicle of the plurality of vehicles includes a single second local network equipped with one of the mobile routers of the plurality of mobile router, an IP address of the second piece of equipment being on the global network, the IP address being private and obtained by concatenating an identifier common to the plurality of vehicles, an identifier of the one vehicle and an identifier of the second piece of equipment on the second local network of the one vehicle on which the second piece of equipment is located, and in that the main and base routing tables storing the identifier of the one vehicle on which the second piece of equipment is located, the main and base routers including a main extracting device and a base extracting device respectively making it possible to extract, from the IP address contained in a header of a datagram to be routed, the identifier of the one vehicle on which the second piece of equipment, to which the datagram is addressed, is located.

31. The system according to claim 21 wherein the plurality of mobile routers and the base routers are connected via the at least one communication infrastructure and the IP addresses on the global network are private IP addresses, the mobile and base routers including a mobile and base encapsulating device respectively for encapsulating and “

de-encapsulating”

the datagrams which the mobile routers and the base routers exchange to allow the datagrams to be routed over the at least one communication infrastructure.

32. A asymmetric IP communication method using the system according to claim 21 for communication between a first, fixed piece of computing equipment located on the ground and connected to a first local network and a second, mobile piece of computing equipment located on board one vehicle of a plurality of vehicles, each vehicle of the plurality of vehicles comprising a second local network equipped with a mobile router, the second piece of equipment being connected to the second local network of the one vehicle on which it is located, the method comprising the following steps, carried out by the mobile router on board the one vehicle:

a) establishing a wireless link between a base station of a communication infrastructure, the base station being equipped with a base radio communication device, and the mobile router including a mobile router radio communication device;

b) after the wireless link is established with the communication infrastructure, testing different IP addresses of base routers connected to the communication infrastructure, and awaiting a response from one of the base routers; and

,

c) connecting the mobile router to the responding base router.

33. The method according to claim 32 further comprising, after the connection with the responding base router has been initialized, the following steps of:

d) storing, in a routing table of the mobile router, the IP address, on the communication infrastructure, of the responding base router to which the mobile router has just connected; and

e) storing, in a routing table of the responding base router, the IP address, on the communication infrastructure, of the mobile router which has just been connected, as well as a reference associated with the IP address, on the global network, of the mobile router;

f) transmitting, from the responding base router to a main router connected to the first local network, a connection status message containing the reference associated with the IP address on the global network of the mobile router as well as the IP address on the global network of the responding base router; and

g) storing, in a routing table of the main router, the IP address on the global network of the responding base router which has transmitted the connection status message and the reference associated with the IP address on the global network of the mobile router.

34. The method according to claim 32 wherein the responding base router, to which the mobile router has just connected, transmits to the mobile router other IP addresses of base routers to update a list of base routers stored in the mobile router.

35. The method according to claim 32 wherein the mobile router uses a mechanism for pre-detecting the loss of an active connection, and if there is a possibility of the active connection being broken, the mobile router stores datagrams to be transmitted in a data file, executes steps a) to c) again to establish another wireless link and a new connection to a base server and, once the new connection has been established, transmits the stored datagrams over the new connection.

36. The method according to claim 32 wherein while the mobile router is connected to a first base router via a first wireless link with a first base station of a first communication infrastructure, the mobile router establishes, by repeating steps a) to c), a second wireless link with a second base station of a second communication infrastructure and connects to a second base router, and in that the main and mobile routers arbitrate to select a route from a first route passing through the first infrastructure and a second route passing through the second infrastructure for ongoing communication between the first and second pieces of equipment.

37. The method according to claim 36 wherein the one vehicle being part of a plurality of vehicles and each vehicle include a single second local network equipped with a mobile router, the IP address of the second piece of equipment on the global network being private and obtained by concatenating an identifier of the plurality of vehicles, an identifier of the one vehicle and an identifier of the second piece of equipment on the second local network of the one vehicle, the step of updating the routing table of the main router consisting of storing the identifier of the one vehicle in the form of a reference associated with the IP address of the mobile router.

38. The method according to claim 37 wherein for downlink communication from the first piece of equipment to the second piece of equipment, the routing executed by the main router, comprising the following steps:

intercepting an IP datagram transmitted over the first local network bound for the second piece of equipment;

extracting the identifier of the one vehicle on which the second piece of equipment is located from the IP address of the second piece of equipment given in a header part of the intercepted IP datagram;

reading, from the routing table of the main router, the IP addresses of the base routers which, at the moment in question, are connected to the mobile router of the one vehicle;

selecting a base router from the connected base routers; and

,

routing the intercepted IP datagram to the base router selected.

39. The method according to any one of claims 32 wherein for uplink communication from the second piece of equipment to the first piece of equipment, the routing executed by the mobile router comprising the following steps:

intercepting an IP datagram transmitted by the second piece of equipment over the second local network bound for the first piece of equipment;

reading, from the routing table of the mobile router, the IP address of the base router currently connected to the mobile router; and

routing the intercepted IP datagram to base router using the wireless link of the associated communication infrastructure with base router.

40. The method according to claim 32 wherein the IP addresses on the global network are private addresses, the step of transmitting an IP datagram between the base router and the mobile router via the communication infrastructure comprising the following steps:

encapsulating an initial IP datagram at a first router, the first router being either the mobile router or the base router;

transmitting the encapsulated IP datagram to the other router via the associated communication infrastructure;

“

de-encapsulating”

the IP datagram received at the other router to extract the initial IP datagram.

41. The system according to claim 26 wherein the short-range wireless communication technology is of a WiFi type or a WiMAX.

42. The system according to claim 29 where in the different technologies are a WiFi technology, a WiMAX technology, a GSM technology, a UMTS technology or a satellite technology.