Radio interference detection and screening system for locomotive control unit radios

• US 6,782,044 B1
• Filed: 02/07/2000
• Issued: 08/24/2004
• Est. Priority Date: 02/07/2000
• Status: Expired due to Term

• Current Assignee: Wabtec Corporation (Westinghouse Air Brake Technologies Corporation)
• Original Assignee: Wabtec Corporation (Westinghouse Air Brake Technologies Corporation)
• Inventors: Wright, Clive B., Glista, Hans
• Primary Examiner(s): Corrielus, Jean B.
• Assistant Examiner(s): Ghulamali, Qutbuddin
• Application Number:
  US09/498,990
• Time in Patent Office: 1,660 Days
• Field of Search: 375/224, 375/225-228, 340/825.61, 340/825.65, 340/825.69, 714/704, 714/706, 714/707
• US Class Current: 375/224
• 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 15/009 On-board display devices
• CPC Class Codes: H04B 17/29 Performance testing
• CPC Class Codes: H04L 1/20 using signal quality detector

Abstract

A radio interference detection and screening system for performs on-locomotive testing of Locomotive Control Unit (LCU) radios. To eliminate bit errors during LCU sensitivity testing (also known as Bit Error Rate (BER) testing), the system detects interfering transmission signals which may cause bit errors in the transmission of test data, and suspends the LCU sensitivity performance testing during periods of detected external transmissions. Once the interfering transmissions are no longer detected by the system, the LCU then resumes the LCU sensitivity performance testing.

Claims

1. A system for testing a railroad telemetry radio using low amplitude test signals near a threshold of the railroad telemetry radio'"'"'s capability to receive error free messages (Bit Error Rate (BER) test message data bits), comprising:

a first counter for counting the BER test message data bits detected by the railroad telemetry radio; and

detection means for detecting interfering signals, the detection means providing a signal to the first counter when the interfering signals are detected,

wherein the first counter suspends counting of received BER test message data bits during the detection of the interfering signal and resumes counting of the received BER test message data bits when the detection means no longer detects the interfering signals.

2. The system of claim 1, further comprising:

a second counter for counting the number of errorless test messages detected by the railroad telemetry radio,

wherein the second counter counts the number of the errorless test messages while a predetermined number of the received BER test message data bits are counted by the first counter.

3. The system of claim 2, wherein:

the first counter is a main bit counter; and

the second counter is a packet counter.

4. The system of claim 2, further comprising means for saving the counted number of received BER test message data bits received during an interval between a beginning of the test and a last received errorless test message.

5. The system of claim 4, wherein the means for saving the counted low amplitude test signals is an auxiliary bit counter.

6. The system of claim 2, further comprising means for returning a pass or fail message depending on whether the total number of counted received BER test message data bits equals the predetermined number and the total number of counted error free messages equal or exceed another predetermined number.

7. The system of claim 1, wherein the first counter and the detection means are embedded within a locomotive control unit associated with the railroad telemetry radio.

8. A method of testing a railroad telemetry radio using low amplitude test signals near a threshold of the railroad telemetry radio'"'"'s capability to receive error free messages (Bit Error Rate (BER) test message data bits), comprising the steps of:

counting the BER test message data bits received by the railroad telemetry radio;

detecting whether an interfering signal is present and providing a signal to the railroad telemetry radio when the interfering signal is detected;

suspending the counting of the received BER test message data bits during the detecting of the interfering signal;

resuming the counting of the received BER test message data bits when the interfering signal is not detected; and

returning a pass or fail message depending on an outcome of the counting and resuming steps.

9. The method of claim 8, further comprising:

setting a packet counter for counting the error free messages to zero;

setting a main bit counter to an initial value, the main bit counter counting the number of received BER test message data bits; and

processing a series of bits of BER test message signals, wherein

the interference detecting step is provided after processing each bit of the series of bits, and

when the interfering signal is detected a value of an auxiliary counter is copied to the main bit counter.

10. The method of claim 9, further comprising determining whether a full errorless message was transmitted to the railroad telemetry radio when the interfering signal is not detected.

11. The method of claim 10, further comprising:

determining whether the main bit counter value is equal to zero; and

determining whether counted error free messages exceed a threshold limit.

12. The method of claim 11, further comprising displaying a “

PASS”

or similar message when the number of error free messages is equal to or exceeds the threshold limit.

13. The method of claim 11, further comprising displaying a “

FAIL”

or similar message when the number of error free messages does not equal to or exceed the threshold limit.

14. The method of claim 11 further comprising incrementing the packet counter when the errorless message is transmitted to the railroad telemetry radio.

15. The method of claim 11, wherein the main bit counter value is not decremented until a valid first message is transmitted and recorded by the railroad telemetry radio to ensure that the railroad telemetry radio is properly synchronized prior to initiation of the testing.