Vehicle data communication

1. A communications system for providing data communication to a vehicle, the communications system comprising:

a mobile transport layer proxy located on the vehicle;

a parent transport layer proxy located remote from the vehicle;

the mobile transport layer proxy being configured to:

accept a transport layer connection with a host device, the host device requesting data from a remote server and the transport layer connection being addressed to the remote server, the mobile transport layer proxy identifying as the remote server at a transport layer for communications with the host device associated with the request for data from the remote server such that the host device communicates as if the host device is communicating with the remote server rather than the mobile transport layer proxy; and

communicate with the parent transport layer proxy via multiple paths using a multipath transport layer protocol to communicate on behalf of the host device to request the data requested by the host device, the mobile transport layer proxy identifying as the mobile transport layer proxy at the transport layer for the communication with the parent transport layer proxy such that the parent transport layer proxy communicates as if the parent transport layer proxy is communicating with the mobile transport layer proxy; and

the parent transport layer proxy being configured to:

communicate with the mobile transport layer proxy using the multipath transport layer protocol;

communicate with the remote server while identifying as the parent transport layer proxy to communicate on behalf of the mobile transport layer proxy to permit the host device to communicate with the remote server to request the data requested by the host device;

communicate with the remote server while identifying as the parent transport layer proxy at the transport layer to receive response data from the remote server, the response data being in response to the data requested by the host device; and

communicate with the mobile transport layer proxy via multiple paths using the multipath transport layer protocol to communicate on behalf of the remote server to send the response data to the mobile transport layer proxy, the parent transport layer proxy addressing the response data to the mobile transport layer proxy rather than the host device and the parent transport layer proxy identifying as the remote server at the transport layer for the communication with the mobile transport layer proxy such that the mobile transport layer proxy communicates as if the mobile transport layer proxy is communicating with remote server.

2. A communications system as claimed in claim 1 , wherein the parent transport layer proxy is configured to accept a connection with the mobile transport layer proxy that is addressed to the remote server.

3. A communications system as claimed in claim 1 , wherein the parent transport layer proxy is configured to communicate with the mobile transport layer proxy via multiple paths using the multipath transport layer protocol.

4. A communications system as claimed in claim 1 , wherein the mobile transport layer proxy is configured to accept the transport layer connection with the host device by intercepting a transport layer session originating from the host device that is addressed for the remote server.

5. A communications system as claimed in claim 4 , wherein the mobile transport layer proxy is configured to accept the transport layer connection with the host device by masquerading as the remote server and terminating the transport layer session originating from the on-board device at the mobile transport layer proxy.

6. A communications system as claimed in claim 1 , wherein the parent transport layer proxy is configured to intercept a transport layer session originating from the mobile transport layer proxy that is addressed for the remote server.

7. A communications system as claimed in claim 6 , wherein the parent transport layer proxy is configured to masquerade as the remote server and terminates the transport layer session originating from the mobile transport layer session at the parent transport layer proxy.

8. A communications system as claimed in claim 1 , wherein the mobile transport layer proxy is connected to a plurality of radio transceivers, each radio transceiver is configured to establish a respective wireless data connection to equipment located remote from the vehicle independently of the other radio transceivers, and each one of the data connections is one of the multiple paths.

9. A communications system as claimed in claim 8 , wherein the plurality of radio transceivers are located on the vehicle.

10. A communications system as claimed in claim 8 , wherein each radio transceiver establishes the respective data connection with a different one of a plurality of base stations located remote from the vehicle.

11. A communications system as claimed in claim 10 , wherein each of the plurality of base stations comprises one of a number of wayside base station next to a path taken by the vehicle.

12. A communications system as claimed in claim 11 , wherein the vehicle is a train and the path taken by the vehicle is a railway track.

13. A communications system as claimed in claim 8 , the communication system comprising a mobile router located on the vehicle, the mobile router comprising the plurality of radio transceivers.

14. A communications system as claimed in claim 13 , wherein the mobile transport layer proxy forms part of the mobile router and the mobile router communicates with the parent transport layer proxy via multiple paths using the multipath transport layer protocol.

15. A communications system as claimed in claim 1 , wherein at least one separate subconnection of the multipath transport layer protocol is established over each of the multiple paths.

16. A communications system as claimed in claim 15 , the mobile transport layer proxy being configured to divide a data stream for transmission to the parent transport layer proxy in to a number of substreams at least equal to the number of paths and send a duplicated or different substream over each of the subconnections.

17. A communications system as claimed in claim 16 , wherein the substreams are formed of data packets and the mobile transport layer proxy is configured to incorporate a data stream identifier in to each data packet, the data stream identifier indicating the position of the data packet in the data stream.

18. A communications system as claimed in claim 15 , wherein the mobile transport layer proxy is configured to divide a data stream for transmission to the parent transport layer proxy in to a number of substreams equal to the number of paths and send a different substream over each of the subconnections.

19. A communications system as claimed in claim 15 , wherein the multipath transport layer protocol is Multipath Transmission Control Protocol (MPTCP), and wherein the at least one separate subconnection is a separate subflow of the MPTCP.

20. A communications system as claimed in claim 1 , wherein a separate subconnection of the multipath transport layer protocol is established over each of the multiple paths.

21. A communications system as claimed in claim 1 , wherein the multipath transport layer protocol is Multipath Transmission Control Protocol (MPTCP).

22. A communications system as claimed in claim 1 , wherein the parent transport layer proxy does not move with the vehicle, and wherein the position of the mobile transport layer proxy is fixed relative to the vehicle.