KR100230581B1 - Communication method of electronic passage fare collecting system - Google Patents

Abstract

The present invention relates to a communication method of an electronic toll collection system which enables processing and confirmation of toll collection work between vehicles traveling at high speed in a communication area even when only a single gantry is used at an exit. In the communication method of the electronic toll collection system according to an aspect of the present invention, the communication method of the electronic toll collection system for collecting charges by the communication between the communication department and the OBU equipped with a smart card processing unit, each of the exit side Setting one communication area managed by the RFC control means after preparing a single RFC control means for each lane; When the OBU exists in the communication area set in each of the exit lanes, the RFC control means charges a charge to the communication department of the OBU, and the communication manager in the OBU controls the smart card processing unit to pay the charge. And a series of processes for confirming by the corresponding RFC control means that the payment of the fee from the OBU is completed while the OBU stays in the communication area.

Description

Communication method of electronic toll collection system

The present invention relates to a communication method of an electronic toll collection system, and more particularly, to a communication method of an electronic toll collection system which enables a complete exit side transaction between a lane controller and a vehicle even under a single gantry structure.

In recent years, thanks to the breakthrough in electronics and telecommunications, the so-called Electronic Toll Collection System (hereinafter referred to as ETCS) has been proposed to enable the vehicle to collect tolls automatically at high speeds. Research for the application is being actively conducted.

The ETCS is provided with a radio frequency communication controller (hereinafter referred to as an RFC controller) in a gantry installed across a lane to correspond to each lane, and a terminal for communicating with the RFC controller in a vehicle. (Hereinafter referred to as an OBU (On Board Unit) in the sense of being installed in a vehicle) is attached. The OBU is composed of a part in charge of communicating with the RFC controller and a smart card (SC), where the SC is used as an electronic wallet in which a predetermined amount is charged in advance.

In the above-described ETCS, the RFC controller and the OBU perform RF communication to exchange necessary information. In this case, a back scattering technique is generally used to simplify the configuration of the OBU. In the 5.8 GHz band, the process of communicating using backscattering is being standardized by the European Organization for Standardization (CEN). In the case of using the backscattering technique, the communication area is reduced compared to otherwise. In general, when the backscattering method is used in the 5.8 GHz band, the size of the communication area is known to be several meters.

On the other hand, in order to perform a payment in the wallet, a series of data processing processes (hereinafter referred to as transactions) are required. This process consists of mutual authentication and encryption, and is generally performed between the communication part of the OBU and the SC. The total payment, including telecommunications, takes hundreds of msecs. As described above, since the time required for the transaction with the SC is excessive, the size of the communication area is limited, so that it is difficult for the vehicle to perform all transactions while driving at a certain speed.

As a solution to solve this problem, a structure is proposed in which two gantry units are installed at appropriate intervals on the exit side. In this structure, ETCS charges in the first gantry, transactions between the in-vehicle communication department and SC are executed between the two gantry, and finally, the second gantry informs the RFC controller of the result. In this manner, it is possible to reliably collect a fee even for a high-speed driving vehicle and further pass the result of the transaction to the RFC controller. However, the configuration is complicated and the installation cost of the RFC controller is increased.

As another method, a system using only one gantry in an exit lane has been proposed. According to this method, only the RFC controller and the OBU communicate in the communication area, and the contents of the communication performed in this process are charged by the RFC controller. The OBU will guarantee the amount paid and the OBU will charge the SC after passing through the gantry. According to this method, there is no problem in the installation cost because the structure is one gantry.

However, since the RFC controller does not check the processing result of the SC, if the transaction between the communication part of the OBU and the SC is not performed normally after passing through the communication area or by the user's intention, the difference is handled. There will be no. That is, the RFC controller reports that the fee has been collected, but there is a problem that a situation in which money is not paid in the SC may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an electronic passage that enables to collect and check a fare collection work between a vehicle traveling at a high speed in a communication area even using a single gantry at an exit. The purpose is to provide a communication method of the toll collection system.

Another object of the present invention is to provide a communication method of an electronic toll collection system that can smoothly perform a toll collection transaction between two vehicles which may inevitably exist in a communication area.

Communication method of the electronic toll collection system according to an aspect of the present invention for achieving the above object is a communication method of the electronic toll collection system to collect charges by the communication between the communication department and the OBU having a smart card processing unit In the lanes on the exit side, after preparing a single RFC control means, setting one communication area managed by the RFC control means; When the OBU exists in the communication area set in each of the exit lanes, the RFC control means charges a charge to the communication department of the OBU, and the communication manager in the OBU controls the smart card processing unit to pay the charge. And a series of processes for confirming by the corresponding RFC control means that the payment of the fee from the OBU is completed while the OBU stays in the communication area.

In the communication method of the electronic toll collection system according to another aspect of the present invention, an electronic toll set a communication area in each lane, and wireless communication related to toll collection between the RFC control means and the OBU is performed in the communication area. In the communication method of the collection system, it is characterized in that the crosstalk is prevented by setting different frequencies of the communication radio signal used in the communication area of the adjacent lane.

According to another aspect of the present invention, there is provided a communication method of an electronic toll collection system, which sets a communication area in each lane and enables wireless communication related to toll collection between the RFC control means and the OBU to be performed in the communication area. A communication method of a toll collection system, characterized in that the transfer of information unilaterally from the RFC control means to the OBU in addition to the mutual communication between the RFC control means and the OBU.

According to another aspect of the present invention, there is provided a communication method of an electronic toll collection system, in which an OBU having a communication manager and a smart card processor performs communication with RFC control means installed in each lane while passing through an inlet and an outlet of a euro road. A communication method of a closed electronic toll collection system that collects tolls at an exit based on a result, wherein communication is performed regardless of whether or not a smart card is inserted in the smart card processing unit during communication at the entrance. It is characterized by one.

In a communication method of an electronic toll collection system according to another aspect of the present invention, a communication area having a size in which a plurality of OBUs may exist in each lane may be set, and the RFC control means may synchronize with a clock having a predetermined period. In the communication method of the electronic toll collection system to transmit a radio signal to the communication area, and to complete a series of wireless communication process related to toll collection in the communication area when there is an OBU passing through the communication area. When there are a plurality of OBUs in the communication area at the inlet side of the closed system, the RFC control means communicates with the back-in vehicle until the series of wireless communication processes relating to the toll collection with the advanced OBU is completed. It is characterized by not starting communication.

1 is a schematic block diagram of an electronic toll collection system to which the present invention is applied;

2 is a view illustrating a lane and a communication area in an electronic toll collection system to which the present invention is applied;

3 is a view illustrating an example of a structure of a communication frame in an electronic toll collection system to which the present invention is applied;

4 is a view for explaining a transaction between the RFC controller and the OBU at the entrance and exit side in the electronic toll collection system according to the present invention, respectively;

5 is a timing chart illustrating a detailed process of a transaction between an RFC controller and one OBU in various cases in the electronic toll collection system according to the present invention;

6 is a diagram illustrating an exit transaction process for two OBUs in the electronic toll collection system according to the present invention.

*** Explanation of symbols for main parts of drawing ***

1: lane, 2: vehicle,

3: communication area, 4: lane separator,

5: maneuver area, 6: RFC controller,

7: ECS, 8: communications department,

9: smart card processing unit

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the communication method of the electronic toll collection system of the present invention.

1 is a schematic block diagram of an electronic toll collection system to which the present invention is applied. As shown in FIG. 1, in the electronic toll collection system to which the present invention is applied, an RFC controller 6 and an ECS (Enforcement Camera System) 7 are installed at each lane side, and a communication department 8 is installed in the OBU. ) And the SC processing unit 9 are provided.

2 is a diagram illustrating a lane and a communication area in an electronic toll collection system to which the present invention is applied. In the example of FIG. 2, three lanes 1 are arbitrarily shown. The area enclosed by an ellipse in the middle of the lane 1 represents the communication area 3, and the size of this communication area 3 can be determined by the RFC controller 6. Each lane 1 is equipped with a separate RFC controller 6, each RFC controller 6 manages only communication with the corresponding lane (1). In general, it is preferable to increase the size L of the communication area 3 as much as possible so that the charge collection process can be confirmed even at a high speed. In this case, several vehicles 2 may exist in the communication area 3. If the size of the communication area 3 is too large, a large number of vehicles exist in the communication area 3 at the same time, which increases the communication burden of the RFC controller. It is recommended to adjust accordingly. In the present embodiment, the description will be made as a maximum of two vehicles can exist in the communication area. In FIG. 2, the symbols f1 and f2 represent different frequencies to prevent jamming that may occur in two adjacent lanes. In front of the communication area 3, a starting area 5 for waking up the OBU waiting in a sleep mode is set, which is common to the entire lane 1. Can be set to Reference sign f3 denotes the frequency of the start signal sent to this start area 5, which starts the frequency signal f1, f2 range, i.e., keeps the start of the communication area 3 accurate. It also functions as a jamming area. That is, while the operation of the OBU is started while the vehicle 2 is in the maneuvering area 5, it is not affected by the frequencies f1 and f2.

Furthermore, since the backscattering technique is used, the OBU responds to both frequencies f1 and f2. Therefore, although the OBU may pass in any lane, the change of the lane 1 in the communication area 3 is prohibited. To this end, it is good to install the structure (4) for separating the lane (1). 2 is applicable to both the inlet and outlet gantry.

In the ECTS having the above-described configuration, the inlet-side gantry delivers identification information of the inlet-side gantry, for example, a unique number (ID) and information about a passing time. Next, at the exit side, the OBU delivers this information to the exit gantry, and at the exit gantry, the OBU delivers the fee determined based on this. Next, the bill charged in this process is processed in the SC 9, and the process ends by notifying the exit gantry again of the processed result. If an abnormality occurs in this process, the ECS (7) installed in the exit side gantry is driven to photograph the number of the vehicle, and based on this, it charges the fee.

Meanwhile, only one gantry is installed at the exit side, and the communication and transaction at the entrance gantry and the exit gantry, two OBUs, and one RFC controller are required to process the verification of the billing contents of the SC within the communication area. The communication method between the two, the recognition of the occurrence of the communication error and the processing method should be complemented, which will be described in detail below.

First, the communication and transaction methods in the entry gantry and the exit gantry will be described in detail. In the communication between the RFC controller and the OBU, a high level data link control (HDLC) protocol is used as a data link layer. This data is then coded using FM0 (Frequency Modulation 0), Manchester, or Non Return-to-Zero I (NRZI), and this value is then converted into an ASK (Amplitude Shift Key) or PSK (Phase Shift Key). After demodulation, RF communication in the 5.8 GHz range is achieved.

3 is a diagram illustrating an example of a structure of a communication frame in an electronic toll collection system to which the present invention is applied, and transmits the same using the same form in the RFC controller and the OBU. 4 is a view for explaining a transaction between the RFC controller and the OBU at the entrance and exit side in the electronic toll collection system according to the present invention. As shown in FIG. 3, the transmission unit in the HDLC protocol is called a "frame", which includes at least an address field (ADD), a control field (CONT), and a message. Field (MSG) is included. The address field (ADD) is typically used to indicate the address of the transmitting or receiving side by consisting of 1 byte and is usually fixed to a constant value. In the present embodiment, ADD = "ffh" may be used for broadcasting. That is, such a address may be used in consideration of the need to unilaterally transmit information from the gantry to the OBU, for example, the need to propagate a road situation or the like. Also, if ADD = "80h", it can be used for communication between RFC controller and OBU, and if ADD = "70h", use of RFC controller to request OBU self-diagnostic result (hereinafter referred to as DG). Can be used as

The control field CONT typically consists of 1 byte of data and is used for various monitoring and control. In more detail, the control field CONT is a request group transmitted to an OBU from an RFC controller such as R0, R1, R2, Q0, Q1, Q2, etc. as shown in FIG. 4 to process a transaction. And a response group transmitted from the OBU such as P0, P1, P2, and ACK to the RFC controller.

Here, R0 and P0 are mutual authentication processes by encryption. R0 includes, for example, current time information and identification information of an entrance gantry (and lane), and P0 includes identification information of an OBU. . The following Q0 and ACK is an authentication verification process by encryption, and the RFC controller inquires on Q0 whether the information received by P0 is correct, and the OBU sends a positive signal to the ACK when the contents of the inquiry are correct. It will be loaded and checked, and the identification information of the entrance gantry will be remembered.

On the exit side, R1 and P1 correspond to the mutual authentication process, and the RFC controller sends the current time information and the identification information of the exit gantry (and lane) to R1, and the OBU identifies which is received and stored in the entrance gantry. Information, identification information of the self and identification information of the inserted SC are carried on P1. In this way, after receiving the information of the OBU, the RFC controller sends a message confirming reception and information about the toll calculated based on the information received from the OBU, to Q1. Finally, the OBU sends a message acknowledging the content received by the Q1 to the ACK. After this process is completed, the OBU performs a process of paying a fee (hereinafter referred to as a debiting process) between the communication department and the SC. Next, the RFC controller sends an inquiry to R2 about whether the payment of its identification information and the fee has been made after a predetermined time has elapsed since the reception of the ACK, and the OBU responds to the R2 to ensure that the payment has been made. The contents will be sent to P2. Next, in Q2 and ACK, a process of reconfirming the contents previously coming from R2 and P2 is performed.

As a result, communication between the RFC controller and the OBU is performed regardless of the state of the SC in the inlet gantry. This means that the user doesn't have to use the SC at the entrance, and it can be used if the normal SC is secured until the exit is reached by purchasing or recharging at the rest stop. Next, when SC is inserted into OBU, OBU checks the status and balance of SC and executes the transaction at the exit according to this content. If the billed fee can be paid normally, two transactions and SC debiting process are performed as shown in FIG. If the fee cannot be paid normally, only one transaction consisting of P1-R1-Q1-ACK is performed. Accordingly, the RFC controller drives ECS to charge back the fee. Of course, the contents of P1 and Q1 in normal and abnormal cases are different.

On the other hand, when removing the SC from the OBU so that all information about the SC can be removed. This allows any SC to be used, which allows the user to use the SC on the way for other purposes, such as purchasing goods or using the passenger's SC. On the other hand, if the user intentionally removes the SC before completing the normal operation at the exit and fails to complete the normal debiting process from the SC, the corresponding OBU is changed to the abnormal state. That is, in such a case, the OBU does not operate normally even when the SC is inserted again (indicative of the situation corresponding to the LCD provided in the vehicle), and the normal operation is performed only after confirming at a nearby SC issuer or charging station.

The next information field (MSG) is the part where the actual information message enters, but the length can basically vary arbitrarily. Start of frame before and after the frame. Flags will be inserted to indicate termination and maintain synchronization. This flag is fixed to a specific pattern of 1 byte, for example, 7eh (O111111O ₂ ). Since only this part of the transmitted data is fixed, the receiving side detects such a bit pattern and knows that the frame is finished. A field ANT not described in FIG. 3 represents an address of an RFC controller, and a field STTS represents a state of an RFC controller or an OBU, and these fields are typically assigned one byte. The field CRC is given for Cyclic Redundancy Check and is allocated 1 byte.

5 is a timing chart illustrating a detailed process of a transaction at the entrance between the RFC controller and one OBU in various cases in the electronic toll collection system according to the present invention. Can be performed. In FIG. 5, the symbol T_CLK represents a transaction clock. When one cycle is defined as t (msec), the interval for transmitting data from the RFC controller to the OBU becomes the initial x (msec), and during the remaining (tx) (msec). Data is transferred from the OBU to the RFC controller. Furthermore, the interval x may vary according to the amount of data to be transmitted. In order for the OBU to normally transmit data to the RFC controller, it should be as short as possible.

In FIG. 5, case 6 represents a case in which an OBU does not exist in a communication area. That is, the RFC controller transmits the request signal R0 three times consecutively every T_CLK. If there is no response, the RFC controller does not perform normal communication for the remaining 5 T_CLK. Case 5 represents a case where communication is completed without an error, and a response signal P0 to the request signal R0 is received, and a time comp for the RFC controller and the OBU to process data during the next T_CLK is secured. Subsequently, the next T_CLK receives a response signal ACK for the request signal Q0 and secures 1 * T_CLK as a time comp to be processed again. In this way, if communication is performed without error, a total of 4 * T_CLK is required. Case 4, Case 3, and Case 2 represent one, two, and three communication errors, respectively. Case 1 represents the worst case. In this embodiment, three retries are allowed for the request signals R0 and Q0, respectively. In the worst case, a total of 8 * T_CLK is required to complete the transaction.

On the other hand, since 8 * T_CLK is a basic unit of a transaction, cases 2 to 6 have a remaining T_CLK. As described above, according to the present invention, the OBU is started by transmitting a start signal having a frequency f3 to the start area set in advance of the communication area, but the OBU enters the communication area due to heavy vehicle delay or reverse. It may be switched back to the deep sleep mode before. In order to prevent this, in case 4 to case 6, a start signal (WU) is generated for forcibly starting the RFC controller at the 7th T_CLK of every transaction unit.

In addition, when case 6 is maintained continuously, it is necessary to determine whether there is no entry of the vehicle or there is an abnormality in the circuit of the RFC controller. For this purpose, in case 5, it is necessary to perform self-diagnosis in the fifth T_CLK of every transaction unit. Generate the signal DG. This self-diagnosis can be performed by setting ADD = 70h as described above.

According to the present invention, since there may be two OBUs in the communication area as described above, the RFC controller should have a function of communicating with both OBUs. To this end, although the first OBU stays in the communication area after completing the transaction, the subsequent OBU and the RFC controller can normally communicate by not responding. That is, as shown in FIG. 5, the entrance RFC controller continuously transmits only the request signal R0 and performs a transaction therefor.

On the other hand, the processing of the transaction for the two OBU at the exit is slightly different from the processing of the transaction at the inlet, Figure 6 shows the exit transaction process for the two OBU in the electronic toll collection system according to the present invention. It is a figure for demonstrating. In FIG. 6, OBU1 is just entering the communication area, and OBU2 is about to exit the communication area. That is, OBU2 has completed the transaction corresponding to the R1-P1-Q1-ACK and the debiting process of the SC. When the result is reported to the RFC controller, the transaction at the exit is completed. When the exit RFC controller does not have a vehicle in the communication area, that is, a new transaction is not started after completion of the entire exit transaction, the exit RFC controller checks whether the OBU exists in the communication area using only the request signal R1. However, when the vehicle enters the communication area, the exit RFC controller transmits the request signals R1 and R2 alternately to simultaneously process a new OBU transaction and an uncompleted OBU transaction. In FIG. 6, since one OBU is continuously present in the communication area even after the fifth T_CLK, the RFC controller alternately transmits request signals R1 and R2, and OBU2 processes SC debiting and then R2-P2-Q2. Complete the transaction via -ACK.

In the manner as described above, for example, the size of the communication area

Assuming that ℓ = 5 m, vehicle speed v = 60 km / h, and the size of T_CLK t = 2 msec, the worst case transaction time for one vehicle at the exit is te = 2 * 8 * 2 = 32 msec Becomes Therefore, the time required for debiting the SC should be within 236msec from the relationship of 3600 * l / v (2 * te + SC_debit ). In this case, one gantry can be normalized at the exit up to 60 km / h.

The transaction method of the electronic toll collection system of the present invention is not limited to the above-described embodiments, and can be modified in various ways within the scope of the technical idea of the present invention. For example, the communication method of the present invention may be applied to an open toll system that collects tolls for all vehicles passing through the gantry without distinction between entrances and exits. Furthermore, the size may be set to allow three or more OBUs to exist in the communication area. In this case, the basic communication method may be similar to that of the two cases.

According to the communication method of the electronic toll collection system of the present invention as described above, only a single gantry is used at the exit, and in this case, the communication burden of the RFC controller, which may occur due to the presence of two OBUs in the communication area, is inevitable. The smooth processing has the effect of reducing the installation cost of the RFC controller.

Claims (31)

In the communication method of the electronic toll collection system that collects charges by communication between an OBU equipped with a communication department and a smart card processing unit, Setting one communication area managed by the RFC control means after preparing a single RFC control means for each lane on the exit side; When the OBU exists in the communication area set in each of the exit lanes, the RFC control means charges a charge to the communication department of the OBU, and the communication manager in the OBU controls the smart card processing unit to pay the charge. And a step of the RFC control means confirming that the payment of the fee from the OBU is completed while the OBU stays in the communication area. The method of claim 1, wherein the charging of the communication unit of the OBU by the corresponding RFC control unit comprises: Sending a current time information and identification information of an exit side to the communication area at a predetermined clock period and requesting a response; Receiving charge related information from the OBU including information indicating that a charge is possible when an OBU exists in the one communication area; Calculating a fee based on the provided fee related information, billing the OBU and requesting a response; And And receiving a response that the OBU has been charged for the electronic toll collection system. The method of claim 2, wherein in the case of a closed system, the fee related information includes at least entrance identification information. 4. The electronic toll collection system of claim 3, wherein the maximum time required to pay the fee between the communication unit in the OBU and the smart card processing unit is determined in relation to the speed of the vehicle and the size of the communication area. Communication method. The method of claim 4, wherein the step of confirming that the corresponding RFC control means confirms that the payment of the fee has been completed includes at least the maximum time required to pay the fee after receiving the response that the corresponding RFC control means has been charged from the OBU. Inquiring of the communication department in the OBU whether the payment has been completed after the elapse of time; And And a communication unit in the OBU notifying the RFC control means that the payment of the fee has been completed. The RFC control means determines that the OBU does not exist in the corresponding communication area when there is no response even when the RFC control means continuously performs a predetermined number of requests for a response. Communication method of electronic toll collection system to do. The communication method of claim 6, wherein when it is determined that the OBU does not exist, a signal for recommending the self-diagnosis is transmitted. 7. The method of claim 6, wherein if it is determined that the OBU does not exist, a start signal is sent. The communication method according to any one of claims 6 to 8, wherein the predetermined number of times is three times. The method according to claim 2, wherein if there is a response signal from the OBU in response to the response request signal of the RFC control means, the RFC control means predetermines a next response request signal before transmitting a next response request signal to secure a data processing time. A communication method for an electronic toll collection system, comprising delaying time by a clock. The communication method of claim 1, wherein if the exit cannot be collected normally, the step of confirming that the payment of the fee is completed is omitted. According to claim 1, If the process of the RFC control means for confirming that the payment of the charge from the OBU is completed in the communication area is not completed normally, charges can be made later by taking a picture of the vehicle equipped with the OBU A communication method in an electronic toll collection system, characterized in that. The method of claim 1, further comprising: in the case of a closed system, setting one communication area managed by corresponding RFC control means in each lane on the entrance side; The RFC control means sends a current time information and the identification information of the inlet side to the communication area at a predetermined clock period to request a response, and when the OBU present in the communication area receives a response request from the RFC control means. Storing the transmitted identification information and time information at the same time, and providing a corresponding RFC control means for responding by completing the series of processes during which the OBU stays in the communication area at the entrance. A communication method for an electronic toll collection system characterized by the above-mentioned. The electronic toll collection system of claim 13, wherein the OBU which has already completed the checking process when the plurality of OBUs exist in the communication area at the entrance side does not respond even if the OBU remains in the communication area. Communication method. The communication method of claim 1, wherein the RFC control means communicates with the respective OBUs alternately when there are a plurality of OBUs in the communication area. 2. A method according to claim 1, wherein the frequencies of radio signals used for communication in at least adjacent lanes are varied in order to prevent interference between lanes. 17. The method of claim 16, wherein lane separation is provided between communication areas of adjacent lanes so that lane change is impossible until communication is started and completed. The communication between the RFC control means and the communication manager of the OBU is performed using an HDLC protocol as a data link layer, wherein an address field of the communication frame in the process is at least the RFC control means and the Communication of the electronic toll collection system, characterized in that the communication between the OBUs, unilateral delivery of information from the RFC control means to the OBU and self-diagnosis recommendations from the RFC control means to the OBU are identifiable. Way. In the communication method of the electronic toll collection system in which a communication area is set in each lane and wireless communication related to toll collection between the RFC control means and the OBU is performed in the communication area, The communication method of the electronic toll collection system, characterized in that the crosstalk is prevented by setting different frequencies of the communication radio signal used in the communication region of the adjacent lane. 20. The method of claim 19, wherein a separation structure is provided between the adjacent communication areas so that the vehicle cannot move to an adjacent communication area after entering a communication area. . 21. The method of claim 19 or 20, wherein the size of the communication area is set such that two OBUs can exist. In the communication method of the electronic toll collection system in which a communication area is set in each lane and wireless communication related to toll collection between the RFC control means and the OBU is performed in the communication area, And a one-sided transfer of information from the RFC control means to the OBU in addition to the mutual communication between the RFC control means and the OBU. 23. The method of claim 22, wherein the RFC control means enables the OBU to request a self-diagnosis. OBU equipped with communication department and smart card processing unit is a closed electronic toll to collect tolls at the exit based on the result of communicating with RFC control means installed in each lane while passing through the entrance and exit of the euro road In the communication method of the collection system, The communication method of the electronic toll collection system, characterized in that during the communication at the entrance side, communication is performed regardless of whether or not a smart card is inserted into the smart card processing unit. An OBU which sets a communication area having a size in which a plurality of OBUs may exist in each lane, transmits a radio signal to the communication area in synchronization with a clock having a predetermined period by an RFC control means, and passes through the communication area. In the communication method of the electronic toll collection system to complete a series of wireless communication process related to toll collection in the communication area when there is, When there are a plurality of OBUs in the communication area at the entrance of the closed system, the RFC control means communicates with the back-in vehicle until the series of wireless communication processes related to the toll collection with the advanced OBU is completed. Communication method of the electronic toll collection system, characterized in that not disclosed. 26. The electronic toll collection claim of claim 25, wherein the advanced OBU does not respond to radio signals from the RFC control means after a series of wireless communication processes relating to tolling with the advanced OBU is completed. The communication method of the system. The RFC control means according to claim 26, wherein the series of communication procedures are updated each time a predetermined number of clocks are generated, and the RFC control means is within the communication area when there is no response for the response request of the RFC control means for a predetermined number of times. A communication method for an electronic toll collection system, characterized in that it is determined that a vehicle does not exist. 28. The method of claim 27, wherein the series of communication processes is updated each time a predetermined number of clocks are generated, and when there is no response until the response request of the RFC control means synchronized with the clock reaches a predetermined reference number. And the RFC control means determines that there is no vehicle in the communication area. 29. The method of claim 28, wherein after determining that the vehicle does not exist, the RFC control means transmits a radio signal for recommending self-diagnosis to the OBU in synchronization with an included clock before the series of communication procedures are updated. Communication method of electronic toll collection system to do. 29. The apparatus of claim 28, wherein after determining that the vehicle does not exist, the RFC control means transmits a radio signal for starting the OBU in synchronization with an included clock before the series of communication procedures are updated. Method of communication in an electronic toll collection system. 31. The toll collection system according to any one of claims 27 to 30, wherein the predetermined number of clocks corresponding to the series of communication processes is set in consideration of occurrence of up to three communication errors. Communication method.

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