WIRELESS COMMUNICATION SYSTEM AND METHOD FOR TRAINS AND OTHER VEHICLES USING TRACKSIDE BASE STATIONS

• US 20170222903A1
• Filed: 01/27/2017
• Published: 08/03/2017
• Est. Priority Date: 01/29/2016
• Status: Active Grant

• Current Assignee: Icomera AB (ENGIE SA)
• Original Assignee: Icomera AB (ENGIE SA)
• Inventors: KARLSSON, Mats, EKLUND, Peter
• Granted Patent: US 10,791,043 B2
• Time in Patent Office: Days
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 45/66 Layer 2 routing, e.g. in Ethernet based MAN's
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/54 based on quality criteria
• CPC Class Codes: H04W 84/005 Moving wireless networks
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

A method and device for wireless communication between a mobile router in a moving vehicle, such as a train, and an external wireless network is disclosed. The external network includes a plurality of base stations distributed along a vehicle path of travel in compliance with a WLAN standard. The method includes: setting a current value for a timeout parameter within the WLAN standard to a default maximum value exceeding a maximum propagation time between neighboring base stations along the vehicle path; determining when at least one mobile router is within the range of a first base station; determining a roundtrip time for communication between the first base station and the mobile router of the mobile router being most distant from the first base station; setting, in case this roundtrip time is significantly lower than the current value, a new current value in dependence on the roundtrip time.

Claims

1. A method for wireless communication between a mobile router in a moving vehicle and an external wireless network comprising a plurality of base stations distributed along a vehicle path of travel in compliance with a Wireless Local Area Network (WLAN) standard, the method comprising:

a) setting a current value for a timeout parameter within the WLAN standard to a default maximum value exceeding a maximum propagation time between neighboring base stations along said vehicle path;

b) determining when at least one mobile router is within the range of a first base station;

c) determining a roundtrip time for communication between the first base station and the mobile router of said at least one mobile router being most distant from said first base station;

d) setting, in case said roundtrip time is significantly lower than said current value, a new current value in dependence on said roundtrip time; and

e) repeating at least steps b-d.

2. The method of claim 1, wherein the timeout parameter is an acknowledgment (ACK) timeout.

3. The method of claim 1, wherein the WLAN standard is IEEE 802.11.

4. The method of claim 1, wherein step a) also includes setting a current slottime to a default maximum value, and wherein step d) also includes setting the current slottime to a new, lower value, in dependence of the determined roundtrip time.

5. The method of claim 1, wherein the step of repeating steps b-d is made periodically at certain time intervals or after a certain waiting time after the last repetition.

6. The method of claim 1, wherein the method is executed in said external mobile network, and wherein the method further comprises transmitting newly set current value(s) to the associated mobile router(s).

7. The method of claim 1, wherein the new current value is set as the sum of said determined roundtrip time and a predetermined constant.

8. The method of claim 1, wherein setting of values for said timeout parameter is made at a Medium Access Control (MAC) layer.

9. The method of claim 1, wherein the roundtrip time is determined as the time elapsing between sending out a packet and receiving a corresponding ACK packet in response.

10. The method of claim 1, wherein the roundtrip time is further estimated based on an estimate of the distance between the mobile router and the first access point, based on GNSS data for the vehicle.

11. The method of claim 1, wherein the mobile router is arranged to simultaneously communicate with the external mobile network through at least two base stations when more than one base station is accessible for the mobile router, thereby providing two concurrently useable data links.

12. The method of claim 1, wherein the mobile router is further arranged to simultaneously communicate with at least one further external wireless network, thereby providing at least one further concurrently useable data link.

13. The method of claim 11, wherein the mobile router is arranged to evaluate the quality of said data links;

and

assigning data streams to said data links at least partly based on said evaluated quality.

14. A computer-readable storage medium encoded with instructions for executing in a wireless device the instructions, when executed, performing a method as defined in claim 1.

15. A wireless device for wireless communication between a mobile router in a moving vehicle and an external wireless network comprising a plurality of base stations distributed along a vehicle path of travel, in compliance with a Wireless Local Area Network (WLAN) standard, the device including a processor arranged to perform the steps:

a) setting a current value for a timeout parameter within the WLAN standard to a default maximum value exceeding a maximum propagation time between neighboring base stations along said vehicle path;

b) determining when at least one mobile router is within the range of a first base station;

c) determining a roundtrip time for communication between the first base station and the mobile router of said at least one mobile router being most distant from said first base station;

d) setting, in case said roundtrip time is significantly lower than said current value, a new current value in dependence on said roundtrip time; and

e) repeating at least steps b-d.