ENHANCED TRANSPONDER PROGRAMMING IN AN OPEN ROAD TOLL SYSTEM

• US 20100245126A1
• Filed: 03/19/2010
• Published: 09/30/2010
• Est. Priority Date: 03/20/2009
• Status: Active Grant

• Current Assignee: Kapsch TrafficCom Canada, Inc. (Datax Handelsgmbh)
• Original Assignee: Kapsch TrafficCom Canada, Inc. (Datax Handelsgmbh)
• Inventors: Malarky, Alastair, Kohli, Japjeev
• Granted Patent: US 8,760,316 B2
• Time in Patent Office: Days
• US Class Current: 340/928
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G

Abstract

A transponder communication system and method for communicating with a transponder in an electronic toll collection system. A roadside reader attempts to program the transponder in a normal mode in which a programming signal is transmitted to a first coverage area. If the programming attempt in the normal mode is unsuccessful, the reader attempts to program the transponder in an enhanced mode in which a programming signal is transmitted to a second coverage area. The coverage area is adjusted after the programming attempt in the normal mode by using an adjacent antenna to the antenna used to transmit in the normal mode or by increasing the power of the programming signal to a level that is greater than the level used to transmit the programming signal in the normal mode.

Claims

1. A transponder communication system for use in an electronic toll collection system for programming a transponder located in a moving vehicle travelling in a roadway, the transponder having a memory, the system comprising:

a plurality of antennas having a coverage area that includes at least a portion of the roadway for transmitting a programming signal and receiving a response signal from the transponder to indicate a successful programming of the transponder; and

a control device connected to the antennas, the control device being configured to direct at least one of the antennas to transmit the programming signal in a normal mode over a first coverage area, the control device being configured to subsequently wait for the response signal and determine whether the transponder has updated its memory using the programming signal, the control device being further configured to direct at least one of the antennas to transmit the programming signal in an enhanced mode if the control device determines that the transponder failed to update its memory, wherein the programming signal is transmitted over a modified coverage area in the enhanced mode.

2. The transponder communication system of claim 1, wherein the programming signal is transmitted at a normal power level in the normal mode and the programming signal is transmitted at a level that is greater than the normal power level in the enhanced mode.

3. The transponder communication system of claim 1, wherein the plurality of antennas comprise a first antenna and a second antenna that is adjacent to the first antenna, and wherein the programming signal is transmitted using the first antenna in the normal mode and the programming signal is transmitted using the second antenna that is adjacent to the first antenna in the enhanced mode.

4. The transponder communication system as claimed in claim 3, wherein there are at least three antennas and wherein the control device is configured to randomly select as the second antenna one of the antennas that is adjacent to the antenna used to transmit the programming signal in the normal mode if there are two antennas that are adjacent to the antenna used to transmit the programming signal in the normal mode.

6. The transponder communication system of claim 1, wherein the control device is configured to determine that the transponder failed to update its memory if the response signal has not been received after a predetermined period of time following the transmission of the programming signal.

7. The transponder communication system of claim 1, wherein the response signal contains data stored in the transponder memory and wherein the control device is configured to transmit a trigger signal prior to waiting for the response signal, and wherein the transponder is configured to transmit the response signal when it receives the trigger signal, and wherein the control device is configured to determine that the transponder has failed to update its memory after a predetermined period of time expires if the response signal has not been received following the transmission of the trigger signal.

8. The transponder communication system of claim 1, wherein the transponder is configured to transmit the response signal containing data in the transponder memory after it has been programmed and wherein the control device is configured to wait for the response signal following the transmission of the programming signal in the normal mode and determine from the response whether the transponder has updated its memory using the programming signal.

9. The transponder communication system of claim 1, wherein the control device is configured to compare the response signal to an expected response signal to determine whether the transponder has updated its memory using the programming signal.

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38. A method of directing communications with transponders in moving vehicles in a roadway, the roadway having a plurality of antennas having a coverage area that includes at least a portion of the roadway, the antennas being configured to operate in a time division multiplexed sequence, the time division multiplexed sequence being comprised of successive superframes, each superframe being comprised of a series of frames, each frame corresponding to communications on one of the antennas, each superframe having a fixed number of frames available for reading data from a memory of the transponder and a fixed number of frames available for writing data to the memory of the transponder, the method comprising:

determining which of the transponders need to be programmed;

selecting for immediate programming at least some of the transponders that need to be programmed based on the fixed number of frames available for writing data;

determining which of the antennas to use for communicating with the transponders that need to be programmed;

determining which frames correspond to the antennas to be used;

allocating the frames of a first superframe which have been determined to correspond to the antennas to be used as writing slots, for writing data to the memory of the transponder; and

allocating a predetermined number of the unallocated frames of the superframe as reading slots.

39. The method of claim 38 further comprising:

allocating all unallocated frames as empty slots.

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53. A transponder communication system for use in an electronic toll collection system for programming a transponder located in a moving vehicle travelling in a roadway, the transponder having a memory, the system comprising:

a plurality of narrow beam reading antennas, each antenna having a coverage area that includes at least a portion of the roadway for transmitting trigger signals and receiving signals transmitted by the transponders in response to the trigger signal;

at least one wide beam programming antenna having a coverage area that includes at least a portion of the roadway for transmitting signals to the transponders, the coverage area of the wide beam antenna being larger than the coverage area of any one of the narrow beam antennas; and

a control device connected to the antennas, the control device being configured to control communications on the antennas, the control device being configured to initiate a reading sequence by causing one of the narrow beam antennas to transmit a trigger signal and awaiting a response on that antenna, the control device being further configured to initiate a writing sequence by causing the wide beam antenna to transmit a programming signal.

54. The transponder communication system in claim 53 wherein the at least one wide beam antenna is positioned downstream from the narrow beam antennas relative to the direction of the vehicle travelling on the roadway.

55. The transponder communication system in claim 53 wherein at least a portion of the coverage area of each wide beam antenna overlaps a portion of the coverage area of one of the narrow beam antennas.

56. The transponder communication system of claim 53 wherein the at least one wide beam antenna is a single antenna having a coverage area that includes the width of the roadway.

57. The transponder communication system of claim 53 wherein the at least one wide beam antenna is a unidirectional antenna.

58. The transponder communication system of claim 53 wherein the control device is configured to cause the wide beam antenna to transmit a wake up signal prior to transmitting a programming signal.

59. The transponder communication system of claim 53, wherein the control device further comprises a transaction processing for processing a payment transaction in response to a receipt of data from the transponders at the narrow beam antennas, the transaction module being configured to issue a request for programming one of the transponders following the processing of the payment transaction for that transponder, wherein the control device is configured to initiate a writing sequence only after the control device has received the request for programming that transponder.

60. The transponder communication system in claim 59 wherein the control device comprises a microprocessor.

61. The transponder communication system of claim 53 wherein the control device is further configured to initiate a verification sequence subsequent to the writing sequence by causing at least one of the narrow beam antennas to transmit a verification signal and waiting for a response from the transponder.

62. The transponder communication system of claim 53 wherein the control device is further configured to initiate a verification sequence subsequent to the writing sequence by causing the at least one wide beam antenna to transmit a verification signal and waiting for a response from the transponder.