Communications: electrical – Vehicle detectors – Discriminates vehicle direction
Reexamination Certificate
2002-04-01
2004-09-14
Goins, Davetta W. (Department: 2632)
Communications: electrical
Vehicle detectors
Discriminates vehicle direction
C340S928000, C340S933000, C235S384000, C342S107000, C342S113000, C342S147000, C701S117000
Reexamination Certificate
active
06791475
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a non-stop electrical toll collection system which is one of Intelligent Transport Systems (ITS), and more particularly to a system and a method that may be advantageously applied to toll collection from a vehicle-mounted device.
BACKGROUND OF THE INVENTION
Recently, a non-stop electrical toll collection system is used in which a roadside device antenna (base station antenna) installed in a toll lane on a toll road such as an express way conduct communication via a wireless link with a vehicle-mounted device (mobile station) provided on a vehicle to send toll charging information to the vehicle-mounted device at an entry or exit location. On the vehicle-mounted device that has received toll information, the toll collection is executed by taking off the toll using an electronic account settlement technique with an IC card and the like connected to the vehicle-mounted device. This system allows a vehicle to electronically pay a toll without having to stop at the tollbooth. A vehicle-mounted device for use in the Electrical Toll Collection (ETC) system, which is commercially available, is mounted for example on a dashboard in the vehicle.
The toll collection technique for use on a vehicle-mounted device in the non-stop electrical toll collection system will be described below with a conventional uniform-toll entry-location collection system in which a vehicle-mounted device is charged for a uniform-toll at an entry location of an express road as an example.
Road-to-vehicle communication between a roadside wireless device (base station) and a vehicle-mounted device functioning as a mobile station is made via control signal sent from the roadside wireless device.
As the vehicle-mounted device approaches the entry tollbooth of a toll road and enters a narrow wireless communication area of the roadside wireless device, the vehicle-mounted device receives the control signal sent from the roadside wireless device.
FIG. 5
illustrates an example of the format of data continuously sent from the roadside wireless device and the format of data sent from the vehicle-mounted device. The diagram in
FIG. 5
is created in the present specification based on the description in page 41 in “(Draft) Electrical Toll Collection System” issued by Association of Radio Industries and Business, December 1999, Revision 1.2, ARIB STD-T55).
FIG. 5
shows an example of the format of down-link, that is, data sent from base station (roadside wireless device) and the format of up-link, that is, data sent from mobile station (vehicle-mounted device).
Referring to
FIG. 5
, the data is composed of frames, each of which is made up of a plurality of slots. The first control signal, termed an “Na” slot, of a frame contains control information
10
on the mobile station (vehicle-mounted device). The Na slot contains a guard time, a preamble (PR) for carrier and clock synchronization, a unique word (UW
1
), control information and an error check code (CRC).
The Na slot, termed a frame control message slot (FCMS), is a slot for frame-multiplexing. One such frame is provided at the start of each frame only for down-link. This slot is used by the base station as a communication control slot to send Frame Control Message Channel (FCMC) composed of frame control information and TDMA slot allocation information. The control information, which will be outlined below, consists of the following fields (not shown in the FIGURE); 2-octets transmission channel control field SIG (Signaling) for layer-
1
channel configuration information and so on, 1-octet frame configuration information field FSI (Frame Structure Information), 1-octet release timer information field RLT (Release Timer information), 7-octets base station service application information field SC (Service Code), and slot control information field SCI (Slot Control Identifier) for communication slot allocation. The SCI includes MDS (Message Data Slot) allocation information comprised of a 1-octet control information sub-field CI (Control Information) and a 4-octets link address field LID (Link ID).
The Nb and Nc slots are message data slots (MDS) which are slots for multiplexing data. One or more (m number of slots) such slots are allocated following the FCMS in one frame. Message data slots (MDS) are multiplexed by the base station in down-link, and by the mobile station in up-link. The number of SCIs is m for the half-duplex mode, and 2 m for the full-duplex mode. In the frame configuration for full-duplex communication, a part of message data slots (MDS) for up-link channels are commonly used for activation slots (ACTS). The attribute of a slot is determined by control information multiplexed into the FCMS.
When road-to-vehicle communication is not conducted, the roadside wireless device composing the base station, sends only Na slots. Nb and Nc slots are empty slots.
As the vehicle-mounted device composing a mobile station, enters the wireless communication area, the vehicle-mounted device first detects the unique word (UW
1
)
9
(
n
) included in the Na slot of the signal sent from the roadside wireless device and makes the time slot of the vehicle-mounted device synchronize with the roadside wireless device.
Then, the vehicle-mounted device receives the control information
10
(
n
) that follows the unique word (UW
1
)
9
(
n
) and checks for a data error using the error check code (CRC)
11
(
n
). If no error is detected as a result of error checking, the vehicle-mounted device analyzes the contents of the control information
10
(
n
) and sends the activation channel, that is wireless link connection request signal, ACTC (Activation Channel)
15
(
n
) to the roadside wireless device using time slots that are available for the vehicle-mounted device for transmission. An activation slot (ACTS) is used only for up-link. There are allocated six channels of windows for the activation channels used for the mobile station to register to the communication link of the base station. In the link establishment phase, the vehicle-mounted device composing a mobile station, selects one of the windows to transmit the ACTC to the base station.
In response to the ACTC
15
(
n
) from the vehicle-mounted device, the roadside wireless device notifies the reception time slots of the vehicle-mounted device using the control information
10
(
n+
1) in the (N+1) a slot (not shown) and sends data to the vehicle-mounted device using the (N+1) b slot or the (N+1) c slot.
The control information
10
(
n+
1) includes information on:
type of roadside wireless device,
link address field LID (Link ID) information on vehicle-mounted device and the like
When the vehicle-mounted device has successfully received data arranged in the (N+1) b slot or (N+1) c slot, it analyzes the contents of data and sends back response data using the transmission time slot indicated by the frame control message slot (FCMS) sent from the roadside wireless device.
The data
14
(
n
) in the Nb slot or the Nc slot includes detailed information regarding the toll collection, being transferred between the roadside wireless device and the vehicle-mounted device. The toll collection is performed normally by transferring this data.
The conventional toll charging processing system described above operates normally when the roadside wireless device is provided at a limited location, that is, at a tollbooth at the entry of a toll road and the like.
However, if this system is applied to a general public road and to a toll collection system that charges a vehicle entering a toll collection area for a toll, the problem is that an erroneous charging to the vehicle may occur.
That is, in a public road of two-way traffics, especially in a lane having a narrow width and a face to face traffic, unlike a one way tollbooth lane at an entry of a toll road, a vehicle exiting a toll collection area must also pass through the wireless communication area of the roadside wireless device.
As a result, the vehicle-mounted device executes roa
Goins Davetta W.
Young & Thompson
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