Communications system and method for interconnected networks having a linear topology, especially railways

• US 6,867,708 B2
• Filed: 08/31/2001
• Issued: 03/15/2005
• Est. Priority Date: 03/17/1997
• Status: Expired due to Fees

• Current Assignee: Albert Donald Jr. Darby, David Poltz, George Jarman, Irfan Ali, Mark Hefner, William Schoonmaker
• Original Assignee: Albert Donald Jr. Darby, David Poltz, George Jarman, Irfan Ali, Mark Hefner, William Schoonmaker
• Inventors: Ali, Irfan, Darby, Albert Donald Jr., Poltz, David, Jarman, George, Schoonmaker, William, Hefner, Mark
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US09/942,624
• Publication Number:
  US 20020027495A1
• Time in Patent Office: 1,292 Days
• Field of Search: 340/933, 340/3.5, 340/505, 455/7, 455/11.1, 701/19, 370/274, 370/327, 370/217, 370/312, 370/315, 370/226, 370/227, 714/713, 375/211, 375/214, 246/167.R, 246/187
• US Class Current: 340/933
• CPC Class Codes: B61L 15/0027 Radio-based, e.g. using GSM-R
• CPC Class Codes: B61L 15/0081 On-board diagnosis or maintenance
• CPC Class Codes: B61L 25/021 Measuring and recording of train speed
• CPC Class Codes: B61L 25/023 Determination of driving direction of vehicle or train
• CPC Class Codes: B61L 25/025 Absolute localisation, e.g. providing geodetic coordinates
• CPC Class Codes: B61L 27/20 Trackside control of safe travel of vehicle or train, e.g. braking curve calculation
• CPC Class Codes: B61L 27/40 Handling position reports or trackside vehicle data
• CPC Class Codes: B61L 3/125 using short-range radio transmission
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 1/1657 Implicit acknowledgement of correct or incorrect reception, e.g. with a moving window
• CPC Class Codes: H04L 1/1803 Stop-and-wait protocols
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 12/40163 by assigning priority to messages according to a message field
• CPC Class Codes: H04L 12/40182 by using a plurality of communication lines
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 12/42 Loop networks
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 2012/40293 the transportation system being a train
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/20 : Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04W 28/26 : Resource reservation
• CPC Class Codes: H04W 40/02 : Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 40/06 : based on characteristics of available antennas
• CPC Class Codes: H04W 40/22 : using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 84/005 : Moving wireless networks
• CPC Class Codes: H04W 88/04 : adapted for relaying to or from another terminal or user

Abstract

A system and method for communicating over networks, particularly generally-linear networks such as a netowrk of railcars in a railway train. The disclosed system and method include the relaying of packets which may contain plural messages down a line of nodes. Acknowledgement of the packets is obtained implicitly by listening to a subsequenct relay of the packet and retransmission of the packet is effected on a diverse antenna in the event of non-acknowledgement. Message bandwidth is shared among the nodes of the system by a message priority system and by the reservation of portions of a packet for certain types of messages. Message bandwidth is also shared by the use of groups of nodes as relay particpiants and by periodically changing the group which is peforming the relay operations.

Claims

1. A method of determining a physical order of plural railcars in a train consist where the railcars are connected to each other through a pneumatic brake pipe and an RF communication link and where the train consist includes at least one head end unit (HEU), comprising the steps of:

a. transmitting a pneumatic pressure pulse along the brake pipe from a selected HEU to the other railcars;

b. transmitting an RF signal from the selected HEU to the railcars;

c. receiving the RF signal at a first railcar;

d. receiving the pneumatic pressure pulse at the first railcar;

e. transmitting an RF message from the first railcar to the HEU indicating the position of the first railcar;

f. receiving the RF signal transmitted by the first railcar at a second railcar;

g. receiving the pneumatic pressure pulse at the second railcar;

h. transmitting an RF message from the second railcar to the to the HEU indicating the position of the second railcar; and

k. for each remaining railcars successively;

(1) receiving at least one RF signal transmitted by another railcar announcing the transmitting railcar'"'"'s relative position;

(2) receiving the pneumatic pressure pulse;

(3) determining the relative position of the railcar as a function of the time between the receipt of the pneumatic pulse and the receipt of the immediately preceding RF message transmitted by another railcar;

(4) transmitting the determined relative position of the railcar to the HEU.

2. The method of claim 1 further comprising the step of modifying the received pneumatic pulse at each railcar prior to retransmission of the pneumatic pulse to thereby facilitate the determination of the time of receipt of the pulse at other railcars.

3. The method of claim 1 further comprising the step of maintaining a log at each railcar, wherein the log includes the time between the receipt of the pneumatic pulse and the receipt of the immediately preceding RF signal from another railcar.

4. The method of claim 3 further comprising steps of transmitting the log from each railcar to the HEU and evaluating the received logs at the HEU to thereby detect errors in the determined position of the railcars.

5. The method of claim 2 where the pneumatic pressure pulse is a positive pulse with respect to the normal pressure of the brake pipe.

6. The method of claim 2 where the pneumatic pressure pulse is a negative pulse with respect to the normal pressure of the brake pipe.

7. In a train comprising at least one head end unit (HEU) and plural railcars connected by a pneumatic brake pipe and an electrical communications link, a method of determining the relative order of the railcars in the train comprising the steps of:

a. transmitting a pneumatic pressure pulse along the brake pipe from the HEU to the plural railcars;

b. transmitting an electrical signal from the HEU announcing the transmission of the pressure pulse;

c. transmitting an electrical signal at each car upon receipt of the pressure pulse;

d. determining the relative order at each railcar as a function of the difference between the time of receipt of the pneumatic pressure pulse and the time of receipt of the immediately preceding electrical signal.

8. In a train comprising at least one head end unit (HEU) and plural railcars, where the HEU and railcars are coupled together through a pneumatic brake pipe and each railcar and HEU contains a communication unit for sending and receiving electrical signals, a method of determining the relative position of each railcar in the train comprising the steps of:

(a) transmitting a pneumatic pulse from the HEU to each railcar through the brake pipe;

(b) transmitting an electrical signal from each railcar to the other railcars and HEU upon receipt of the pneumatic pulse; and

(c) determining the relative position of each railcar in the train as a function of the difference in time between receipt of the pneumatic pulse and the electrical signal transmitted by another railcar.

9. The method of claim 8 wherein the electrical signal from the step of determining is the immediately preceding electrical signal received from another railcar.

10. The method of claim 8 wherein the step of transmitting an electrical signal from each railcar includes announcing the relative position of the transmitting railcar in the train.

11. In a train comprising at least one head end unit (HEU) and plural railcars where the HEU and railcars are coupled together through a pneumatic brake pipe and each railcar and HEU contains a communication unit for sending and receiving messages, a method of each railcar determining its relative position of each railcar in the train, comprising the steps of:

a. transmitting a pneumatic pulse from the HEU to each railcar through the brake pipe;

b. transmitting an electrical signal from the HEU to the railcars;

c. receiving the pneumatic pulse at a railcar;

d. transmitting an electrical signal from each railcar upon receipt of the pneumatic pulse;

e. determining the relative position of each railcar in the train as a function of the time of receipt of the pneumatic pulse and the receipt of an electrical signal from another railcar.

12. The method of claim 11 wherein the electrical signal from the step of determining is the immediately preceding electrical signal received from another railcar.

13. The method of claim 11 wherein the relative order is determined by measuring at each railcar the time between the receipt of the pneumatic pulse and the receipt of the latest received electrical signal from another railcar.

14. The method of claim 13 further comprising the step of transmitting the measured information from each railcar to the HEU.

15. The method of claim 14 further comprising the step of evaluating the measured data received from the railcars to identify errors in the determined position of the railcars in the train.

16. The method of claim 11 wherein the step of transmitting an electrical signal from each railcar includes the step of monitoring for the transmission of other railcars prior to transmitting to thereby avoid having multiple railcars claim the same relative position in the train.

17. In a train comprising at least one head end unit (HEU) and plural railcars where the HEU and railcars are coupled together through a pneumatic brake pipe and each railcar and HEU contains a communication unit for sending and receiving electrical signals, a method of determining the relative position of each railcar in the train comprising the steps of:

a. transmitting an electrical signal and a pneumatic pulse from the HEU to each railcar;

b. transmitting an electrical signal from each railcar upon receipt of the pneumatic brake pulse;

c. determining the relative position of each car in the train as a function of the difference in time between the receipt of the pressure pulse and the receipt of the last received electrical signal.

18. The method of claim 17 wherein the step of transmitting an electrical signal from each railcar comprises transmitting the determined position of the railcar in the train.

19. The method of claim 17 further comprising the step of:

d. modifying the received pneumatic pulse at each railcar prior to retransmission of the pneumatic pulse to thereby facilitate the determination of the time receipt of the pulse at other railcars.

20. In a method of determining the relative position of plural railcars in a train having at least one head end unit (“

LIEU”

) where the HEU and all of the railcars are connected by pneumatic and wireless communication systems, the improvement wherein each railcar transmits a wireless signal upon receipt of a pneumatic signal and determines its relative position in the train from the difference in time between the receipt of a pneumatic signal originating from the HEU and the receipt of a wireless signal transmitted by the immediately preceding railcar.

21. The method of claim 20 wherein the railcar originating the wireless signal changes as a function of the receipt of the pneumatic signal at the railcars in the train.

22. In a method of determining the relative position of plural railcars in a train having at least one head end unit (“

HEU”

) where the HEU and all of the cars are connected by a common pneumatic communication system and where the HEU and each of the railcars is connected to a plurality of the railcars by a wireless communication system, the improvement wherein each railcar transmits a wireless signal upon receipt of a pneumatic signal and determines its relative position in the train using the time of receipt of the wireless signal received over the wireless communication system in closest proximity to receipt of a pneumatic signal.

23. In a train comprising at least one head end unit (HEU) and a plurality of railcars connected by a pneumatic brake pipe and an electrical communications link with each railcar in the train and the HEU, a method of determining the order of the railcars comprising:

a. transmitting a pneumatic pressure pulse along the brake pipe so as to travel in sequence to each railcar of said plurality of railcars;

b. receiving the pneumatic pressure pulse at the railcars in the train;

c. transmitting an electrical signal from each of the plurality of railcars indicative of the time at which the pneumatic pressure pulse was received at the respective rail car; and

d. determining the order of the railcars in the train based on the time of receipt of the electrical signals transmitted by the plurality of railcars.

24. The method of claim 23 further comprising establishing and recording the order of the railcars at the HEU.

25. The method of claim 23 wherein the electrical signal comprises a unique address assigned to each railcar based on the time at which the pneumatic pressure pulse reached the transmitting railcar.

26.The method of claim 25 wherein the unique address is a numerical identifier indicating the position of the other railcars in the train.

26. The method of claim 26 wherein each one of the plurality of railcars self-determines the unique address based on of the railcar in the train.

27. The method of claim 27 wherein each railcar transmits an address-containing electrical signal after self-determining a unique address, and wherein subsequent railcars self-determine an address based on the address-containing electrical signal received from previous railcars in the train.

28. The method of claim 27 wherein upon receiving the pneumatic pressure pulse, the receiving railcar vents the segment of the brake pipe on the receiving railcar.

29. In a train comprising at least one head end unit (HEU) and a plurality of railcars connected by a pneumatic brake pipe and an electrical communications link with each railcar in the train and the HEU, a method of determining the order of the railcars comprising:

a. transmitting a first electrical signal from the HEU to the plurality of railcars announcing the transmission of a pressure pulse along the brake pipe;

b. transmitting a pneumatic pressure pulse on the brake pipe to the plurality of railcars, wherein the pneumatic pressure pulse is received at each of the plurality of railcars after receipt of the first electrical signal;

c. transmitting a second electrical signal from each of the plurality of railcars indicative of the time at which the pneumatic pressure pulse was received at the respective rail car the transmitting rail car;

d. determining the order of the railcars in the train based on the time of receipt of the second electrical signals.

30. The method of claim 30 further comprising establishing and recording the order of the railcars at the HEU.

31. The method of claim 30 wherein the second electrical signal is indicative of a unique address assigned to each railcar based on the time at which the pneumatic pressure pulse reached the transmitting rail car.

32. The method of claim 30 wherein the second electrical signal comprises a unique address indicating the position of the railcar in the train, and wherein the second electrical signal is received by at least one other of the plurality of railcars for use in determining the position of the receiving railcar in the train.

33. The method of claim 32 wherein the unique address is transmitted from each one of the plurality of railcars to the HEU in response to a polling signal transmitted from the HEU.

34. In a train comprising at least one head end unit (HEU) and plural railcars connected by a pneumatic brake pipe and an electrical communications link, a method of determining the relative order of the railcars in the train comprising the steps of:

a. transmitting a first electrical signal announcing a transmission of a pressure pulse along the brake pipe to the railcars;

b. transmitting a pneumatic pressure pulse along the brake pipe to the plurality of railcars, with each railcar receiving the pneumatic pulse at a different time from that of the other railcars in the train, with said time being later than that of the preceding railcars and earlier than that of successive railcars;

c. transmitting a sequence of second electrical signals from the railcars, with one of said second electrical signals being transmitted for each railcar upon receipt of the pressure pulse at that respective railcar; and

d. determining the relative order at each railcar in the train as a function of the time of receipt of said second electrical signals.