Method and means for RF toll collection

Details Method and means for RF toll collection Method and means for RF toll collection

2002-01-31

2003-12-09

Tong, Nina (Department: 2632)

Communications: electrical

Traffic control indicator

Combined

C235S384000

Reexamination Certificate

active

06661352

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to the field of RF toll collection wherein, in a roadway environment, vehicle borne transponders communicate with a stationary reader or readers to establish the toll for the vehicle carrying the transponder.
BACKGROUND OF THE ART
Patents relating to such field include:
U.S. Pat. No. 4,104,630 August 1978 Chasek
U.S. Pat. No. 4,303,904 Dec. 1, 1981 Chasek
U.S. Pat. No. 4,870,419 Sep. 26, 1989Baldwin et al
U.S. Pat. No. 4,937,581 Jun. 26, 1990 Baldwin et al
U.S. Pat. No. 5,132,687 Jul. 21, 1992 Baldwin et al
U.S. Pat. No. 5,164,732 Nov. 17, 1992 Brockelsby et al
U.S. Pat. No. 5,192,954 Mar. 9, 1993 Brockelsby et al
U.S. Pat. No. 5,196,846 Mar. 23, 1993 Brockelsby et al
U.S. Pat. No. 5,289,183 Feb. 22, 1994 Hassett et al
DISCLOSURE OF THE INVENTION
For conventions herein, the traffic flow eastbound and from left to right in the drawings may be thought of as representative of all directions.
Toll Plaza is the name for the toll collection point.
Electronic Toll Collection may be shortened to ‘ETC’.
By ‘transaction manager’ is meant a device for coordinating an upstream and a downstream reader, toll processing calculator, and locator.
‘Point of Entry’ data or ETC data; includes sufficient information to calculate the toll charge and usually includes: point of entry, toll plaza ID, vehicle class and transponder ID.
A wide area is an area materially wider than the width required by a lane for a roadway vehicle hence a wide area roadway is materially wider than a single lane highway.
A wide area reader is typically used for a wide area RF communication system incidental to toll collection. The wide area capture zone is typically 16.8 meters (55 feet) wide by 36.6 meters (120 feet) long. The wide area reader typically uses a protocol known as Time Division Multiple Access (TDMA).
A lane based reader controls reader channels, each one of which corresponds to an individual vehicle lane which will communicate with a vehicle in an individual lane. A lane communication capture zone is typically 1.2 to 2.4 meters (4-8 feet) long and 3 meters (10 feet) wide. A vehicle in a lane capture zone may be uniquely identified.
Time Division Multiple Access (TDMA) is the preferred communications protocol in the upstream capture zone.
A conventional TDMA frame consists of a header known as a Frame Control Message (FCM), four data slots and sixteen activation slots of the type known as slotted Aloha. The FCM directs up to four transponders individually to transmit or receive in the four data slots. The activation slots are shared by all transponders on a random access basis to allow the transponder to notify the reader of its presence. A TDMA frame is approximately 10 ms long.
In this development it is preferred to extend the conventional TDMA protocol, to include optional new added fields desirable for communicating with a Smart Card toll system and at the same time maintain compatibility with the conventional TDMA system.
The preferred added fields may include:
Application Identifier Field—This field is used to inform the transponder which application is running in the reader, so that upon wake up, the transponder can initialize the on board device accordingly. Under the development, as described herein, the reader will only operate in accord with the first or wide area protocol. However, other applications, not part of the toll collection system described, may be added at another time.
Frame Number Field—This field is used by the transponder for antenna tracking and switching.
Antenna Number Field—This field is used by the transponder for antenna tracking.
Antenna Tracking and Switching Control—This field is used by the transponder to select the antenna tracking and antenna switching so that it can be dynamically controlled by the reader.
Media Request Activation Control Field (MRA)—This field is used by the reader to command the transponder whether to transmit an MRA after the required process is completed.
Protocol Control Field—This field is used by the reader to command the transponder to go to sleep mode or to switch to lane based protocol after the first protocol is complete.
The added fields maybe arranged in any order in their position at the start of the FCM frame.
The TDMA system with the added fields is referred to herein as ‘extended TDMA’.
‘Superframe’; In the system preferred herein there are four TDMA (preferably extended) RF channels. A superframe is a complete cycle of the four channels by the TDMA Reader with one frame being cyclically transmitted on each antenna. A superframe for four channels is approximately 40 ms in duration.
‘ID’; means ‘Identification’.
‘Tag’; is sometime used herein as a synonym for transponder.
‘Upstream’ and ‘Downstream’; herein relate to position relative to traffic flow. Vehicles move from an upstream position to a downstream position.
A reader is a stationary transmitter receiver which enters into RF communications protocol with a vehicle borne transponder. The preferred embodiment uses a wide area reader which, upstream, enters into a first communication protocol with a vehicle borne transponder and a second or lane based reader which downstream, provides a plurality of channels each for an individual lane, one of which enters into a second protocol with the same transponder.
A principal variant of the invention uses, for RF communication, a transponder equipped with a Smart Card which may be electronically and mechanically coupled thereto, usually being optionally detachable. This variant as well as the description as a whole relates to the methods of using the Smart Card. The Smart Card equipped transponder is used in a roadway environment having a first reader defining an upstream RF communication or ‘capture’ zone designed to communicate with vehicle borne transponders over a roadway area wider than a single lane, to obtain from the transponder information for a transaction manager allowing the calculations as to toll amount and payment status. The data thus obtained is associated with the transponder ID and a second lane based downstream reader is connected to receive by downstream RF communication the status of payment and transponder ID.
The lane based readers are designed to define downstream communications zones designed to associate the transponder ID and payment status uniquely with vehicle travelling in an individual lane. Preferably the lane based reader is connected to a lane controller which directs the vehicle carrying the subject transponder to stop or go in accord with the payment status.
In a preferred variant of the invention the transponder provides the first reader with the information from the transponder and its Smart Card including the balance from which the toll may be deducted. This information is provided to calculating and coordinating means, here called a transaction manager, which calculates the toll and directs the Smart Card via the first reader and transponder to debit the toll amount and deduct it from the account balance. Then the Smart Card provides a completion message which includes: a payment status report, which may be ‘paid’; ‘insufficient balance’ or another condition; a certificate of payment to the transaction manager; and a signature for the financial institution. The transaction manager is equipped to report the payment status independent of the transponder and Smart Card to the second reader which is adapted to deal individually with the vehicles and which will physically associate the status and vehicle ID with a vehicle then in an individual lane and customarily direct the vehicle with the subject transponder usually by means of light signals typically attached to a lane controller.
The process as described provides the required security of financial information and account balances unlike the prior art use of a single reader. The use of a transaction manager provides a communication path from the wide area reader communication zones to the lane based reader which parallels that of the vehicle borne transponder. The transaction manager also provides a highly f

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