JP4574398B2 - Method for determining availability of communication connection between base station apparatus of narrow area communication system and mobile station apparatus thereof - Google Patents

Description

  The present invention relates to a narrow-area wireless communication system that performs wireless communication between a base station device installed on a road and a mobile station device mounted on a vehicle, and in particular, distinguishes communication connection requests from mobile station devices. The present invention relates to a method for determining whether or not a communication connection between a base station apparatus and its mobile station apparatus is possible.

  Development of Intelligent Transport Systems (ITS), which integrates roads and vehicles, in order to realize services aimed at improving safety, transport efficiency, and comfort It has been. In this system, various services using wireless communication such as road-to-vehicle communication between a base station device installed on the road and a mobile station device mounted on a vehicle and vehicle-to-vehicle communication between mobile station devices can be realized. For example, in road-to-vehicle communication, in addition to being applied to an automatic toll payment system (ETC) for toll roads, it is also being planned to develop payment services and information provision services at parking lots and gas stations. .

  As an example of the road-to-vehicle communication system in this ITS, narrow area communication (limited communication area (area in which communication is possible between the base station apparatus and the mobile station apparatus) is limited to a relatively narrow range of several meters to several tens of meters. A DSRC (Dedicated Short-Range Communication) method is known (for example, see Non-Patent Document 1).

  This DSRC method employs a synchronous time division communication method in which communication frames are time-divided into fixed-length sections called slots.

  FIG. 7 is a diagram showing a configuration example of a communication frame in the DSRC system. FIG. 7A shows a configuration example when the base station apparatus performs full duplex communication operation, and FIG. An example of the configuration when the station apparatus performs a half-duplex communication operation is shown.

  7 (a) and 7 (b), the slots constituting the communication frame are roughly divided into a communication slot and a control slot. The communication slot is configured so that communication with a plurality of mobile station apparatuses is possible. A plurality of message data slots (MDS) for exchanging data between vehicles are arranged. In the following, it is assumed that eight communication slots are arranged, half of which four are used for downlink communication from the base station apparatus to the mobile station apparatus, and the remaining four are from the mobile station apparatus to the base station apparatus. Used for upstream communication to. The control slot includes control information necessary for road-to-vehicle communication, and includes a frame control message slot (FCMS) for storing configuration information of a communication frame transmitted by the base station apparatus and a usage status of the communication slot, The mobile station apparatus includes an activation slot (ACTS) for transmitting a connection request signal for requesting communication connection to the base station apparatus.

  In the communication frame for full-duplex communication shown in FIG. 7A, a frame for transmitting a frame control signal (FCMC) described later as a control slot in downlink communication from the base station apparatus to the mobile station apparatus. Four communication slots corresponding to the slot control fields (SCI (1), (3), (5), (7)) of this frame control signal (FCMC) follow, starting with the control message slot (FCMS). . These four communication slots are assigned to message data slots (MDS) for exchanging data between road vehicles by means of slot control fields (SCI (1), (3), (5), (7)). In uplink communication from the mobile station apparatus to the base station apparatus, the slot control field (SCI () of the frame control signal (FCMC) is used at each communication slot timing allocated to the message data slot (MDS) in downlink communication. 2), (4), (6), and (8)) are arranged for communication slots, and these communication slots are arranged in the slot control field (SCI (2),) of the frame control signal (FCMC). According to (4), (6), (8)), a message data slot (MDS) or an activation slot (ACTS) as a control slot is allocated.

  When the communication slots having the same timing in downlink communication and uplink communication are message data slots (MDS), downlink communication and uplink communication can be performed simultaneously in these communication slots. In the activation slot (ACTS) at the same timing as the message data slot (MDS), a connection request signal for requesting communication connection is transmitted from the mobile station apparatus to the base station apparatus.

  Further, in the communication frame for half duplex communication shown in FIG. 7B, a frame control message slot (FCMS) for downlink communication of a frame control signal (FCMC) from the base station apparatus to the mobile station apparatus at the head thereof. ) Is assigned, and subsequently, four downlink communication slots and four uplink slots are alternately assigned. Therefore, a message data slot (MDS) is assigned to the i-th (where i = 1, 2, 3) downlink communication slot and the (i + 1) -th uplink communication slot following this. When the downlink communication from the base station apparatus is performed in the i-th message data slot (MDS), the uplink communication from the mobile station apparatus is performed in the (i + 1) -th message data slot (MDS) in response to this. Done. In addition, an activation slot (ACTS) is assigned to the communication slot for uplink communication by the slot control field (SCI (2), (4), (6), (8)) of the frame control signal (FCMC). Then, a connection request signal for requesting communication connection is transmitted from the mobile station apparatus to the base station apparatus in this activation slot (ACTS).

  As shown in FIG. 8, a frame control signal (FCMC) composed of frame synchronization, frame information, slot-specific control information, and error detection code (CRC) is transmitted to the frame control message slot (FCMS).

  As shown in the figure, the frame information of the frame control signal (FCMC) includes a transmission channel control field (SIG) for storing physical layer characteristics such as a protocol version code (PVI) and a physical profile identifier (PPI), and this base station apparatus. An identification number field (FID) for storing the identifier of the frame, as shown, a frame configuration information field (FSI) for storing information relating to the frame configuration such as a communication mode identifier (CM) and slot number information (SLN), from the mobile station device The release timer information field (RLT) for suppressing the reconnection of a predetermined time and the service application information field (SC) for storing an identifier for identifying the service provided by the base station apparatus.

  The control information for each slot of the frame control signal (FCMC) is composed of a plurality (here, 8) of slot control information fields (SCI), and each slot control field (SCI (1), (2), .., (8)) correspond to the respective communication slots in FIG. In FIG. 7, this correspondence is indicated by SCI (1), (2),..., (8).

  The slot control field (SCI (1), (2),..., (8)) is composed of a control information subfield (CI) and a link address subfield (LID). The control information subfield (CI) is attribute information (slot identifier (SI)) indicating whether the communication slot shown in FIG. 7 is assigned as a message data slot (MDS) or an activation slot (ACTS). And the type of signal arranged in the message data slot (MDS). For example, as shown in the figure, when the slot identifier SI = 00, the corresponding communication slot in FIG. 7 is assigned to the message data slot (MDS), and when the slot identifier SI = 11, the activation slot (ACTS). Assigned to. Then, when the slot identifier SI = 00 and the communication slot is assigned to the message data slot (MDS), the signal type and the like are, as shown, the transmission rate identifier (DRI), the signal type identifier (ST), When the communication slot is assigned to the activation slot (ACTS) and is represented by the signal direction identifier (DR), and the slot identifier SI = 11, the signal type and the like are shown in FIG. ) Or congestion information (STA).

  The link address subfield (LID) of the slot control field (SCI) indicates the address of the mobile station apparatus assigned to the communication slot in FIG. As a result, the usage status of the communication slot such as which mobile station apparatus is assigned the message data slot (MDS) can be determined.

  On the other hand, in the activation slot (ACTS), connection request signals (ACTC) can be arranged for six channels as shown in FIG. 9, and connection requests from a plurality of mobile station apparatuses can be received simultaneously. . This connection request signal is composed of channel synchronization, connection request information and an error detection code (CRC). The connection request information includes an identifier (FID) of a base station apparatus of the other party making the connection request, and this mobile station. The device link address (link address subfield (LID)) and link request information (LRI) indicating the contents of the connection request are stored.

  When an application system using this narrow area communication (DSRC) system is introduced in a parking lot or a gas station, the base station device uses a feature that is spot communication that limits the communication area, and the base station device is in a predetermined position (for example, an entrance). Application services such as payment and information provision are possible for vehicles in the communication area (vehicles equipped with a mobile station device) formed in the communication area formed in front of the delivery gate or at a position adjacent to the fueling machine. However, in practice, a region with a relatively high electric field strength is formed at an unexpected position due to the influence of reflected waves from structures arranged around the base station apparatus, and the mobile station apparatus reacts to this. There are cases. As a result, there is a possibility that communication with a mobile station apparatus that does not exist in a predetermined position, that is, in the communication area occurs, and there is a problem that a target person (that is, a vehicle) that provides a service is mistaken.

To solve this problem, measure the strength of the signal transmitted by the mobile station device at the base station device, and handle only the signal transmitted from an appropriate position (where sufficient signal strength can be obtained). A method for preventing misidentification of a target person to be provided has been proposed (see, for example, Patent Document 1).
JP 2003-289582 A The Japan Radio Industry Association “Narrow Area Communication (DSRC) System Standard ARIB STD-T75”

  However, according to the prior art described in Patent Document 1, the base station device is assumed to be a target person who is provided with service for all the mobile station devices that have entered the communication area of the base station device and have reached an appropriate position. There was a problem that would be determined. For example, in a case where a communication area by a base station device is arranged adjacent to a refueling machine at a gas station, when a plurality of refueling machines exist on the same site, a plurality of communication areas are arranged close to each other. Will be. And when a user moves a vehicle to a desired refueling machine in such an environment, the mobile station device mounted on the vehicle will stop until the vehicle stops in a communication area adjacent to the desired refueling machine. In the meantime, several communication areas will be passed. In addition, in some cases, there is a vehicle that simply passes through the place in the course of movement in addition to entering the communication area for the purpose of using the service. However, in the prior art described in Patent Document 1, since the signal strength is a condition for determining whether or not there is a mobile station device in the communication area, whether it has entered the communication area for receiving a service, Whether it has simply entered this communication area cannot be distinguished, and even if an attempt is made to start providing a service, a problem arises in that there is no service providing target at that time.

  The object of the present invention is to solve such a problem, and to make it possible to determine whether the purpose of a vehicle entering the communication area is service use or simply passing through this communication area. An object of the present invention is to provide a method for determining whether or not a communication connection between a base station apparatus of a system and its mobile station apparatus is possible.

In order to achieve the above object, at least a communication connection transmitted by a mobile station apparatus is established in a base station apparatus of a narrow-area communication system that is installed on a road and performs wireless communication with a mobile station apparatus mounted on a vehicle. Based on a connection request signal for requesting the base station device, communication connection determining means for determining whether or not communication connection with the mobile station device is possible, the communication connection determining means is within a predetermined time. From the comparison result of the number of receptions of the connection request signal counted to the base station apparatus and the threshold of the predetermined number of receptions calculated from the size of the communication area determined by the base station device and the speed of the vehicle, The purpose of intrusion is determined, and when the purpose corresponding to the number of receptions equal to or greater than the threshold of the number of receptions is determined, the acceptance determination of the communication connection request from the mobile station apparatus is performed.

In addition, the communication connection determination means is a predetermined value calculated from the number of receptions of the connection request signal counted within a predetermined time determined in advance , the size of the communication area determined for the base station apparatus, and the vehicle speed. From the result of comparison with the threshold value of the received number of receptions, the purpose of entering the communication area of the vehicle is determined, and the integrated reception level obtained by sequentially integrating the reception levels indicating the signal strength of the connection request signal for which the number of receptions is counted is Whether the mobile station device is within the communication area based on the comparison result between the average reception level divided by the number of receptions and the threshold value of the average reception level that is the lower limit of the reception strength of the connection request signal determined by the base station device as the communication area. If the purpose of the number of times of reception is equal to or greater than the threshold of the number of times of reception is determined, and the determination result that the connection request signal is from the mobile station device in the communication area is obtained, Station equipment It is characterized in that for performing reception determination et communication connection request.

In order to achieve the above object, the present invention provides a communication connection with a mobile station device of a base station device of a narrow area communication system that performs wireless communication with a mobile station device installed on a road and mounted on a vehicle. In the admission / rejection determination method, each time a connection request signal for requesting the base station apparatus to make a communication connection transmitted by the mobile station apparatus is received within a predetermined time, the number of times the received connection request signal is received is counted. A step, a step of comparing the counted number of receptions with a threshold of a predetermined number of receptions calculated from the size of the communication area determined for the base station device and the speed of the vehicle, and the number of receptions is equal to or greater than the threshold And a step of accepting a communication connection request from the mobile station apparatus.

Further, each time a connection request signal for requesting the base station apparatus to make a communication connection transmitted by the mobile station apparatus is received within a predetermined time, the step of counting the number of times the received connection request signal is received; A step of comparing the counted number of receptions with a threshold of a predetermined number of receptions calculated from the size of the communication area determined for the base station device and the speed of the vehicle; and a connection request signal for counting the number of receptions A step of integrating reception level values indicating signal strength, dividing the integrated reception level value by the number of receptions to obtain an average reception level value, and the number of receptions being equal to or greater than a predetermined reception number threshold and the average reception level; when the value is not less than the threshold value of the average received level of the lower limit value of the reception strength of the connection request signal by the base station apparatus determined as the communication area, ingredients and a step of accepting a communication connection request from the mobile station apparatus It is characterized in that the.

  The running state in the communication area set by the base station device is intended to use services such as payment and information provided in this communication area, or simply use this communication area. According to the present invention, the traveling state of the vehicle is detected by detecting the number of receptions of the connection request signal transmitted from the mobile station device mounted on the vehicle. Therefore, it is possible to reliably discriminate between a vehicle intended to use the above service and a vehicle that simply passes through the communication area.

  Further, according to the present invention, the traveling state of the vehicle is determined by detecting the number of times of reception of the connection request signal from the mobile station device mounted on the vehicle, and the average reception level of the connection request signal is determined. Determine whether the mobile station device has transmitted a connection request signal from within the communication region set by the base station device, or has transmitted a connection request signal from within an unexpected region caused by the influence of reflected waves, etc. Therefore, the base station apparatus that has transmitted the connection request signal from within the communication area can be reliably discriminated, and the vehicle that is intended to use the above service can be discriminated more accurately.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a first embodiment of a base station apparatus of a narrow area communication system according to the present invention. Reference numeral 5 denotes communication control means, 6 denotes application processing means, and 7 denotes an input terminal.

  In the first embodiment, the connection request transmitted by the mobile station apparatus is used to distinguish whether the purpose of the vehicle entering the communication area formed by the base station apparatus is service use or simply passing through the communication area. The signal (ACTC) reception count is measured, and based on the measurement result, the communication connection with the mobile station apparatus is determined.

  In FIG. 1, the base station apparatus according to the first embodiment includes an antenna 1, modulation / demodulation means 2, communication connection determination means 3, communication management means 4, communication control means 5, and application processing means 6. In order to enable a mobile station apparatus (not shown) to detect the communication area formed by the frame, a frame control signal (FCMC) having the configuration shown in FIG. 8 is periodically transmitted in the communication frame shown in FIG. The wireless communication for providing the application service is started by accepting the connection request signal (ACTC) transmitted by the mobile station apparatus that has detected the control signal (FCMC).

  The modem 2 demodulates the received signal B input from the antenna 1 and outputs it to the communication controller 5 in order to perform mutual communication with the mobile station apparatus via the antenna 1, and supplies it from the communication controller 5. The transmission signal A is modulated so that the carrier wave is modulated and output to the antenna 1.

  On the other hand, the communication management means 4 manages a time reference for forming a communication frame as shown in FIG. 7, and is a communication slot attribute (message data slot (MDS)) to the communication control means 5. Or whether it is an activation slot (ACTS)) or an instruction regarding transmission / reception timing. The communication management means 4 also manages communication frame configuration information, communication slot usage, and the like, and constitutes a frame control signal (FCMC) according to the above time reference. A control signal E stored in the control information is output to the communication control means 5. Furthermore, the communication management means 4 also manages the state of communication connection with the mobile station apparatus. In this connection state management, the determination notification D supplied from the communication connection determination means 3 is used as a trigger, and the mobile station apparatus instructed by the determination notification D is added to the management target and processing for providing an application service is performed. Information F for notifying the application processing means 6 of the communication connection with the mobile station apparatus is output.

  As shown in FIG. 7, the communication control means 5 transmits and receives management information in the frame control message slot (FCMS) according to the attribute and timing of the communication slot instructed by the communication management means 4 and for communication. Transmission / reception processing of communication data in the slot is performed.

  In this management information transmission process, frame synchronization (FS) and error check code (CRC) are added to control information (frame information and slot-specific control information in FIG. 8) E supplied from the communication management means 4 A process of generating a control signal (FCMC) and outputting it to the modulation / demodulation means 2 is performed. In the management information reception process, the connection request signal (ACTC) supplied from the modem unit 2 is output to the communication connection determination unit 3 during the period in which the communication management unit 4 instructs the activation slot (ACTS). The process to do is performed.

  In the message data slot (MDS) communication data transmission / reception process, the application processing means 6 performs a process for exchanging communication data with the mobile station apparatus. For this purpose, the communication control means 5 is a protocol in which control information that defines the processing procedure on the mobile station apparatus side that is the transmission destination is added to the communication data at least when communication data is supplied from the application processing means 6. When transmission control for generating data is performed and communication data from the mobile station apparatus is received, control information is extracted from protocol data generated by the mobile station apparatus that is the transmission source, and reception control is performed. To. At this time, in order to exchange protocol data with the mobile station apparatus in the message data slot (MDS) assigned by the communication management means 4, the communication control means 5 is at the timing indicated by the communication management means 4. It operates so as to exchange protocol data with the modem 2.

  When the determination request signal C is input from the input terminal 7, the communication connection determination means 3 is triggered by this connection request signal (ACTC) based on the connection request signal (ACTC) supplied from the communication control means 5. It is determined whether or not communication connection with the mobile station apparatus that has transmitted

  FIG. 2 is a flowchart showing a first embodiment of a method for determining whether or not a connection request with a mobile station apparatus of a base station of a narrow area communication system according to the present invention is executed by the communication connection determining means 3.

  In the figure, the communication connection determination means 3 monitors the state of the input terminal 7 (whether or not the determination request signal C is input), and when the determination request signal C is input and there is a communication connection determination request (step) S201), the value of the number of times of reception Nr is initialized (step S202), a timer set with a predetermined time indicating timeout (hereinafter referred to as timeout time) is started, and the passage of time is measured (step S203).

  It is determined whether or not the timer measurement time has exceeded this timeout time (this is hereinafter referred to as the timer timing out) (step S204). If the timer has not timed out, has the communication frame been updated? A determination process of whether or not is performed (step S205). When the communication frame is updated, the control information of the frame control signal (FCMC) (the frame information and the control information for each slot in FIG. 8) is output from the communication management means 4 to the communication control means 5 to the communication control means 5 to control the communication control. As described above, the means 5 generates a frame control signal (FCMC) by adding a frame synchronization signal (FS) or an error check code (CRC) to this control information, and supplies this to the modulation / demodulation means 2 for transmission. However, the frame control signal (FCMC) is also supplied to the communication connection determination means 3, and the frame control signal (FCMC) is detected by detecting the frame synchronization signal (FS) of the frame control signal (FCMC). ) Is transmitted, that is, it is determined that the communication frame has been updated.

  If the communication frame is not updated, the process returns to step S204, and the processes of steps S204 and S205 are repeated until the communication frame is updated unless the timer times out.

  When the communication frame is updated, it is determined whether or not a valid connection request signal (ACTC) has been received (step S206). This is because when the received connection request signal (ACTC) is output from the modulation / demodulation means 2, it is supplied to the communication connection determination means 3 via the communication control means 5, but the communication connection determination means 3 is supplied with this Whether or not there is an error in the connection request signal (ACTC) using the error check code (CRC) added to the connection request signal (ACTC), that is, whether the connection request signal (ACTC) is valid. It is to be inspected. If there is an error, the process proceeds to step S204 and waits for the input of a new connection request signal (ACTC) until the timer times out. If there is no error, it is determined that the received connection request signal (ACTC) is valid.

  When a valid connection request signal (ACTC) is received, the number of receptions Nr is integrated by 1 (step S207), and the process returns to step S204. If the connection request signal (ACTC) is not received or if there is an error in the connection request signal (ACTC) even if it is received, the process returns to step S204.

  In this way, a series of procedures are repeatedly executed until the timer times out, and the number Nr of receptions of valid connection request signals (ACTC) is accumulated during that time.

  When it is detected that the timer times out (step S204), the number of receptions Nr accumulated until the timer times out is compared with a preset threshold value Nt (step S208). If it is equal to or greater than the threshold value Nt, the communication management means 4 outputs a determination notification D instructing that the connection request of the mobile station apparatus at this time has been accepted (step S209), and the communication connection to this mobile station apparatus This determination process ends. If the number of receptions Nr is less than the threshold value Nt (step S208), the mobile station apparatus connection request is not accepted and the process is terminated.

  In this way, communication connection can be performed only for the mobile station apparatus that has received the connection request signal (ACTC) for the number of times equal to or greater than the threshold value Nt.

  In the first embodiment, the lower limit value of the number of times of reception of a connection request signal (ACTC) for discriminating a vehicle passing through a passing area set by the base station apparatus is determined by the threshold value Nt. Since the mobile station apparatus can transmit the connection request signal (ACTC) only within the communication area in which the frame control signal (FCMC) transmitted by the base station apparatus can be received, for example, the size of the communication area set by the base station apparatus Is A (m), the communication frame length is Tf (sec), and the number of receptions is Nr, the speed Vt of the vehicle passing through this communication area is approximately A / (Tf × Nr) (m / sec). Here, since the size A of the communication area and the communication frame length Tf are unique values according to the use scene such as a parking lot or a gas station, the traveling speed Vt of the vehicle can be determined from the number of receptions Nr. Accordingly, the discrimination speed of the vehicle can be determined by setting the threshold value Nt for the number of receptions Nr.

  Therefore, in the first embodiment, when the vehicle travels at a low speed at which the service can be provided or stops, the purpose of the vehicle entering the communication area set by the base station apparatus is discriminated. In addition, the communication area set by the base station apparatus is set by setting the reception frequency Nr of the connection request signal (ACTC) for the maximum low speed at which the vehicle can receive the service provided to the above threshold Nt. It is possible to determine whether the purpose of the vehicle entering the vehicle is to use a provided service or simply to pass through this communication area.

  In addition, depending on the environment in the installation area of the base station device, the base station device may receive connection request signals (ACTC) from a plurality of mobile station devices at the same time. In such a case, the mobile station apparatus stored in the link address subfield (LID) (FIG. 9) of the connection request signal (ACTC) is identified so that the reception frequency Nr is obtained for each mobile station apparatus. A link address may be used, and the number of receptions Nr may be distinguished for each link address. In addition, the number Nr of connection request signals (ACTC) received from a plurality of mobile station apparatuses may exceed the threshold value Nt. In this case, communication connection processing may be performed according to the contents of the service to be provided. it can. For example, a process of performing communication connection with all these mobile station apparatuses, a process of performing communication connection only with a mobile station apparatus having the largest number of receptions Nr, or processes such as processing in time series with priorities assigned by the number of receptions Nr. Applicable.

  In addition, it is specified that a mobile station apparatus of a narrow area communication (DSRC) system repeatedly transmits a connection request signal (ACTC) up to 127 times until communication connection is completed. On the other hand, since the size of the communication area and the communication frame length are limited depending on the usage scene, in some cases, it may not be possible to secure the measurement time required to detect the low-speed traveling state. In such a case, the mobile station apparatus is controlled by control information such as a time division identifier (TDI) or congestion information (STA) shown in FIG. This can be dealt with by increasing the period for assigning the activation slot (ACTS) and the transmission repetition period for the connection request signal (ACTC).

  In the first embodiment, the determination request signal C input from the input terminal 7 is used as a trigger to determine whether communication connection with the mobile station apparatus is possible. Such a determination request signal C In response to the new reception of the connection request signal (ACTC), the mobile station apparatus that transmits the newly received connection request signal (ACTC) is allowed to enter the communication connection determination operation. May be.

  FIG. 3 is a flowchart showing a second embodiment of a method for determining whether or not a connection request with a mobile station apparatus of a base station of a narrow area communication system according to the present invention is executed by the communication connection determining means 3 in FIG.

  In the first embodiment of the communication connection feasibility determination method shown in FIG. 2 above, after the timer times out, the number of receptions Nr is compared with the threshold value Nt (step S208), and according to the comparison result. The determination notification D is output to the communication management means 4 (step S209). However, in the second embodiment of the communication connection availability determination method shown in FIG. 3, it takes place before the timer times out. A comparison is made to determine whether or not communication connection is possible, and a determination notification D is output to the communication management means 4 according to the determination result.

  Also in the second embodiment of the communication connection feasibility determination method, the communication connection determination unit 3 is triggered by the determination request signal input from the input terminal 7, and is connected to the connection request signal (ACTC) supplied from the communication control unit 5. Based on the above, it is determined whether or not communication connection with the mobile station apparatus that has transmitted the connection request signal (ACTC) is possible.

  1 and 3, the state of the input terminal 7 is monitored (step S201), and a determination request signal is input from the input terminal 7, as in the first embodiment of the communication connection availability determination method shown in FIG. When there is a communication connection determination request, the reception count Nr is initialized (step S202), and a timer with a predetermined measurement time set as a timeout time is started to measure the elapsed time (step 203).

  Then, it is determined whether or not the timer has timed out (step S204). If the timer has timed out before a determination notification D to be described later is output, the mobile station apparatus connection request is not accepted. The process ends.

  If the timer does not time out, a process for determining whether or not the communication frame has been updated is performed (step S205). As in the case of step S205 shown in FIG. 2, this determination process is performed when the frame synchronization signal (FS) of the frame control signal (FCMC) supplied from the communication control means 5 is detected, so that the communication frame is updated. It is determined that

  If the communication frame is not updated, the process returns to step S204, and the processes of step S204 and step S205 are repeated until the communication frame is updated unless the timer times out.

  When the communication frame is updated, processing for determining whether or not a valid connection request signal (ACTC) has been received is performed (step S206). As in the case of step 206 shown in FIG. 2, when the connection request signal (ACTC) received from the communication control means 5 is supplied, this determination process uses this error check code (CRC) to connect to this connection request signal (CRC). It is determined whether or not there is an error in (ACTC) and whether or not this connection request signal (ACTC) is valid. If there is an error, the process proceeds to step S204 and waits for the input of a new connection request signal (ACTC) until the timer times out.

  If the received connection request signal (ACTC) has no error (that is, is valid), the number of receptions Nr is integrated by a value 1 (step S207), and the obtained number of receptions Nr is compared with a threshold value Nt (step S207). S301). As a result of the comparison, if the number of receptions Nr is less than the threshold value Nt, the process returns to step S204.

  In this way, every time a valid connection request signal (ACTC) is received, the series of operations in steps S204 to S301 is repeated to accumulate the number of receptions Nr, and the number of receptions Nr becomes the threshold value Nt before the timer times out. When the above is reached (step S301), the communication management unit 4 outputs a determination notification instructing that the connection request of the mobile station apparatus at this time has been received (step S302), and the communication connection determination process is terminated. If the timer times out before the number of receptions Nr becomes equal to or greater than the threshold value Nt (step S204), the communication connection determination process is terminated without outputting a determination notification.

  As described above, in the second embodiment shown in FIG. 3, as in the first embodiment shown in FIG. 2, only the mobile station apparatus that can receive the connection request signal (ATCT) equal to or higher than the threshold value Nt is targeted. And a lower limit value of the traveling speed for discriminating the passing vehicle in the passing area can be determined by the threshold value Nt. By setting the number Nr of connection request signal (ACTC) receptions that can be determined as a threshold value Nt, it is possible to distinguish whether the purpose of the vehicle entering the communication area formed by the base station apparatus is service use or simply passing through the location. Will be able to. When a plurality of mobile station apparatuses transmit a connection request signal (ACTC) at the same time, the number of receptions Nr is distinguished for each mobile station apparatus as in the first embodiment shown in FIG. For this, a link address (link address subfield (LID)) for identifying the mobile station apparatus stored in the connection request signal (ACTC) may be used.

  In the second embodiment shown in FIG. 3, since the number of receptions Nr is integrated and the number of receptions Nr is compared with a threshold value Nt, communication is performed when the threshold value Nt is exceeded even if the timer does not time out. Connection determination can be completed, the effect of shortening the determination time can be obtained, and the following effect can be obtained.

  That is, when a plurality of vehicles enter in time series like a parking lot entrance / exit, it is desirable to provide services in order from the preceding vehicle. For this purpose, it is necessary to design the communication area to be narrow and to reduce the influence of reflected waves so that the following vehicle does not react. In the case of the second embodiment shown in FIG. 3, a difference occurs in the timing at which mobile station devices mounted on sequential vehicles capture the communication area (timing to enter the communication area), and is formed due to the influence of reflected waves. Since the connection request signal (ACTC) from the transmitted communication area cannot be stably received, the connection request signal (ACTC) from the preceding vehicle is accumulated first and the connection request signal from the following vehicle is added. Even with (ACTC), it is possible to prioritize and discriminate the preceding vehicle. In addition, since a relatively wide communication area can be allowed, there is an advantage that the degree of freedom in antenna design is increased. For example, in the case of a patch antenna, if the communication area is narrowed, the number of elements increases and the shape also increases. However, in the specific example shown in FIG. The antenna becomes available.

  Note that, similarly to the first embodiment shown in FIG. 2, the second embodiment shown in FIG. 3 also has a frame control signal ( This can be dealt with by controlling the mobile station device with the control information (FIG. 8) stored in the FCMC, and increasing the cycle of assigning the activation slot (ACTS) to the communication frame and the cycle of repeating the connection request signal (ACTC). Further, as to the trigger for determining whether or not communication connection is possible, the connection request signal (ACTC) is newly received without providing the input terminal 7 for the determination request signal C as in the first embodiment shown in FIG. As a result, it is possible to enter into a communication connection availability determination operation.

  FIG. 4 is a block diagram showing a second embodiment of the base station apparatus of the narrow-area communication system according to the present invention, 2 'is modulation / demodulation means, 3' is communication connection determination means, and corresponds to FIG. The same reference numerals are given to the portions, and overlapping description is omitted.

  In the second embodiment, not only the connection request signal (ACTC) from the mobile station apparatus but also the signal strength of the received signal from the modulation / demodulation means is used for the determination of the communication connection of the mobile station apparatus. It is.

  In FIG. 4, the modem 2 'demodulates the received signal from the mobile station device (not shown), detects the signal strength (reception level) of the received signal, and communicates the value as the received level value Sa. It supplies to the connection determination means 3 '. The communication connection determination means 3 'is detected by the reception frequency Nr of the reception connection request signal (ACTC) supplied from the communication control means 5 and the modulation / demodulation means 2' triggered by the input of the determination request signal C from the input terminal 7. The connection request signal (ACTC) is calculated based on an average reception level value Ma obtained by dividing an integrated value (hereinafter referred to as an integrated reception level value) Ra of the reception level value Sa of the connection request signal (ACTC) by the number of receptions Nr. It is determined whether communication connection with the transmitted mobile station apparatus is possible.

  FIG. 5 is a flowchart showing a third embodiment of a method for determining whether or not a connection request with a mobile station apparatus of a base station of a narrow area communication system according to the present invention is executed by the communication connection determination means 3 '.

  In the figure, the communication connection determination means 3 ′ monitors the state of the input terminal 7 (whether or not the determination request signal C is input), and when the determination request signal C is input and there is a communication connection determination request ( In step S201), the number Nr of effective connection request signals (ACTC) received and the integrated reception level value Ra are initialized (step S501), and a timer with a predetermined measurement time set as a timeout time is started to measure the elapsed time. (Step S203).

  It is determined whether or not the timer has timed out (step S204). If the timer has not timed out, a process for determining whether or not the communication frame has been updated is performed (step S205). In this determination processing, the frame synchronization signal (FS) of the frame control signal (FCMC) supplied from the communication control means 5 is detected as in step S205 of the first embodiment shown in FIG. Thus, it is determined that the communication frame has been updated.

  If the communication frame is not updated, the process returns to step S204, and the process of steps S204 and S205 is repeated to wait for the update of the communication frame unless the timer times out.

  When the communication management unit 4 outputs control information to the communication control unit 5 to update the communication frame in order to transmit the frame control signal (FCMC), the connection request signal (ACTC) supplied from the communication control unit 5 is updated. ) Is determined whether it is valid (step S206). As in the case of step 206 in the first embodiment shown in FIG. 2, this determination process uses an error detection code (CRC) when a connection request signal (ACTC) is supplied from the communication control means 5. It is determined whether or not the connection request signal (ACTC) is valid.

  When the received connection request signal (ACTC) has no error (that is, is valid), the value 1 is added to the number of receptions Nr, and the signal strength of the connection request signal (ACTC) is calculated from the modem 2 '. The indicated signal level value Sa is acquired and integrated with the integrated reception level value Ra (step S502). When there is an error in the received connection request signal (ACTC) (step S206), or when the integration process in step S502 is completed, the process proceeds to step S204, and the above-described series of steps are repeated until the timer times out, Every time a valid connection request signal (ACTC) without error is received, the value 1 is sequentially added to the number of receptions Nr, and the reception level value Sa is sequentially added to the integrated reception level value Ra.

  When it is detected that the timer has timed out (step S204), the number of receptions Nr integrated until the timer times out is compared with a preset threshold value Nt (step S208). If it is equal to or greater than the threshold value Nt, the average reception level value Ma per reception of the connection request signal (ACTC) received from the mobile station device is calculated by dividing the integrated reception level value Ra by the integrated number of receptions Nr. (Step S503). The calculated average reception level value Ma is compared with a preset threshold value Mt (step S504). If the average reception level value Ma is equal to or greater than the threshold value Mt, the mobile station apparatus is informed to the communication management means 4. A determination notification indicating that the connection request has been accepted is output (step S209), and the communication connection determination process is terminated.

  When the number of receptions Nr is less than the threshold value Nt (step S208) or when the average reception level value Ma of the valid connection request signal (ACTC) is less than the threshold value Mt (step 504), the connection request of this mobile station apparatus Ends the process without accepting.

  Thus, in the third embodiment of this communication connection determination method shown in FIG. 5, the number of receptions of the connection request signal (ACTC) from the mobile station apparatus is equal to or greater than the threshold value Nt, and the average reception level value Ma is Communication connection can be performed only for the mobile station apparatus having the threshold value Mt or more. Therefore, as in the first embodiment shown in FIG. 2, the lower limit value of the traveling speed for discriminating passing vehicles can be determined by the threshold value Nt. Further, from the mobile station device at that time, The communication area is also evaluated by obtaining the average reception level value Ma of the connection request signal (ACTC). The communication area formed at a predetermined position by the base station apparatus has a high signal level and is relatively stable. However, in the communication area formed by the influence of the reflected wave, the reception level value of the connection request signal (ACTC) Since Sa is low and fluctuations are large, the average reception level value Ma has a discriminable difference between the former communication area and the latter communication area. Further, when the threshold Mt of the average reception level value Ma is the lower limit value of the reception intensity of the connection request signal (ACTC) determined by the base station device as the communication area, the average reception level value Ma is compared with this threshold Mt, thereby It can be determined whether or not the mobile station apparatus is transmitting a connection request signal (ACTC) from within the communication area defined by the station apparatus.

  Therefore, in the third embodiment of the connection request availability determination method shown in FIG. 5, by setting the number Nr of reception of connection request signals (ACTC) that can be determined as low-speed running or stop capable of providing a service as the threshold value Nt. , It is possible to distinguish whether the purpose of the vehicle that enters the communication area formed by the base station device is to use the service or to simply pass through the location, and it is continuously received at a stable signal level. Since the mobile station apparatus that transmits the connection request signal (ACTC) can be identified from the position, the mobile station responds from an unexpected position (that is, a position in the communication area formed by the influence of the reflected wave). Discrimination from the device is also possible.

  Note that in the third embodiment of the communication request availability determination method shown in FIG. 5 as well, as in the first embodiment shown in FIG. 2, a plurality of base station devices may be used depending on the installation environment of the base station device. In some cases, a connection request signal (ACTC) is simultaneously received from the mobile station apparatuses. In such a case, the mobile station apparatus stored in the link address subfield (LID) shown in FIG. 8 of the connection request signal (ACTC) is identified so that the reception frequency Nr is obtained for each mobile station apparatus. A link address may be used to distinguish the number of receptions Nr for each ring address. Further, the number Nr of receptions of connection request signals (ACTC) from a plurality of mobile station apparatuses may exceed the threshold value Nt, and the average reception level value Ma may exceed the threshold value Mt. In such a case, communication connection processing can be performed according to the content of the service to be provided. For example, priority is given to processing for performing communication connection with all these mobile station devices, processing for performing communication connection only to the mobile station device having the largest reception frequency Nr or average reception level value Ma, or reception frequency Nr or average reception level value Ma. Processing such as ranking and handling in time series is applicable.

  Similarly to the first embodiment shown in FIG. 2, when the measurement time necessary for detecting the low-speed running state cannot be secured, the frame control signal (FCMC) is stored. 8, a cycle for allocating an activation slot (ACTS) to a communication frame, and a cycle for repeatedly transmitting a connection request signal (ACTC) by controlling the mobile station apparatus using control information such as time division identifier (TID) and congestion information (STA) shown in FIG. This can be done by making the length longer. Also, whether or not communication connection with the mobile station apparatus is possible is not triggered by the fact that the connection request signal (ACTC) is newly received without using the determination request signal C, as in the first embodiment. It is also possible to enter the determination operation.

  FIG. 6 is a flowchart showing a fourth embodiment of a method for determining whether or not a connection request with a mobile station apparatus of a base station of a narrow area communication system according to the present invention is executed by the communication connection determination means 3 'in FIG.

  In the third embodiment shown in FIG. 5, after the timer times out, the comparison of the number Nr of receptions of the valid connection request signal (ACTC) and the threshold Nt (step S208) and the average of the reception level value Sa Value, that is, the average reception level value Ma and the threshold value Mt are compared (step S504) to determine whether or not communication connection is possible, and a determination notification D is output to the communication management means 4 according to the determination result (step S504). In the fourth embodiment shown in FIG. 6, the determination is made every time a valid connection request signal (ACTC) is received during the period until the timer times out. The determination notification D can be output to the communication management means 4 according to the above.

  The base station apparatus that executes the fourth embodiment shown in FIG. 6 also has the configuration shown in FIG. 4, and its communication connection determination means 3 ′ is triggered by the determination request signal C input from the input terminal 7, Based on the number Nr of receptions of the effective connection request signal (ACTC) supplied from the communication control means 5 and the reception level value Sa of the effective connection request signal (ACTC) from the modulation / demodulation means 2 ′, this connection request signal. It is determined whether or not communication connection with the mobile station apparatus that has transmitted (ACTC) is possible.

  4 and 6, the state of the input terminal 7 is monitored (step S201), as in the third embodiment shown in FIG. 5, and a communication connection determination request signal C is input from the input terminal 7 to perform communication. When there is a connection determination request, the number of receptions Nr and the integrated reception level value Ra are initialized (step 502), and a timer with a predetermined measurement time set as a timeout time is started to measure the elapsed time (step 203). ).

  It is determined whether or not the measurement time of the timer has exceeded this timeout time (step S204), and if the timer times out before the determination notification D to be described later is output, the mobile station device The process ends without accepting the connection request.

  If the timer has not timed out, it is determined whether or not the communication frame has been updated (step S205). Similar to step S205 in FIG. 2, this determination processing determines that the communication frame has been updated by detecting the frame synchronization signal (FS) of the frame control signal (FCMC) supplied from the communication control means 5. To do.

  If the communication frame is not updated, the process returns to step S204, and unless the timer times out, steps S204 and S205 are repeated to wait for the update of the communication frame.

  When the communication management unit 4 outputs control information to the communication control unit 5 to transmit a frame control signal (FCMC) and the communication frame is updated, it is determined whether or not the connection request signal (ACTC) is valid. Processing is performed (step S206). This determination process is similar to step S206 in FIG. 2, when the connection request signal (ACTC) is supplied from the communication control means 5, the connection request signal (ACTC) received using the error detection code (CRC). It is determined whether or not is valid.

  When there is no error in the received connection request signal (ACTC) (that is, when it is valid), the value 1 is added to the number of receptions Nr, and the signal strength of this connection request signal (ACTC) is obtained from the modem unit 2 ′. Is obtained and integrated with the integrated reception level value Ra (step S502). Then, the obtained number of receptions Nr is compared with the threshold value Nt (step S208). If the comparison result shows that the number of receptions Nr is equal to or greater than the threshold value Nt, the integrated reception level value Ra obtained in step S502 is received. The average reception level value Ma per reception of the connection request signal (ACTC) from the mobile station apparatus divided by the number of times Nr is calculated (step S503), and this average reception level value Ma is set to a preset threshold value Mt. (Step S504). If the average reception level value Ma is equal to or greater than the threshold value Mt, the communication management unit 4 outputs a determination notification instructing that the connection request for the mobile station apparatus has been received (step S209). The determination process ends.

  When there is an error in the received connection request signal (ACTC) (step S206), when the number of receptions Nr is less than the threshold value Nt (step S208), or when the average reception level value Ma is less than the threshold value Mt (step) In step S504, the process proceeds to step S204, and the above-described series of procedures is repeatedly executed until the determination notification D can be output or the timer times out.

  As described above, in the base station apparatus according to the second embodiment shown in FIG. 4 using the communication connection request determination method shown in FIG. 6, the connection is made in the same manner as when the communication connection request determination method shown in FIG. 5 is used. Communication connection can be made only for mobile station devices whose request signal (ACTC) reception number Nr is equal to or greater than the threshold value Nt and whose average reception level value Ma is equal to or greater than the threshold value Mt. Since it is possible to set an upper limit value of the vehicle traveling speed for discriminating vehicles entering the communication area for the purpose of receiving the provided service, it can be determined that the service can be provided at low speed or stopped. Whether the purpose of the vehicle entering the communication area formed by the base station device is service use by setting the connection request signal (ACTC) reception frequency Nr as the threshold value Nt. It will be able to distinguish whether a mere passage of place. Furthermore, since it becomes possible to identify a mobile station apparatus that transmits a connection request signal (ACTC) from a position where a stable reception level can be continuously obtained, communication formed by an unexpected position (that is, an influence of a reflected wave) It is also possible to discriminate from the mobile station apparatus that responds from the position in the area.

  In the base station apparatus according to the second embodiment that performs the communication connection request determination shown in FIG. 6 as well, the base station apparatus depends on the installation environment of the base station apparatus as in the base station apparatus shown in FIG. May simultaneously receive connection request signals (ACTC) from a plurality of mobile station apparatuses. In such a case, the mobile station apparatus stored in the link address subfield (LID) shown in FIG. 8 of the connection request signal (ACTC) is identified so that the reception frequency Nr is obtained for each mobile station apparatus. A link address may be used to distinguish the number of receptions Nr for each ring address.

  Further, in the second embodiment in which the communication connection request determination process shown in FIG. 6 is performed, these are compared with the threshold value Nt and the threshold value Mt during the procedure of accumulating the reception count Nr and the reception level value Sa. Even if the timer does not time out, the determination result of the communication connection request determination process can be obtained when the number of receptions Nr exceeds the threshold value Nt and the average reception level value Ma of the integrated reception level value Ra exceeds the threshold value Mt. The determination time can be shortened.

  Further, in the second embodiment of the base station apparatus shown in FIG. 4 using the communication connection request determination method shown in FIG. 6, as in the first embodiment of the base station apparatus shown in FIG. When a plurality of vehicles enter in chronological order like the entrance / exit of a car, it is possible to discriminate preferentially from the preceding vehicle and to move from the unexpected position. Discrimination from station equipment is also possible. Further, as in the first embodiment of the base station apparatus shown in FIG. 1, it is also possible to allow a relatively wide communication area, so that there is an advantage that the degree of freedom in antenna design is increased.

  In the fourth embodiment shown in FIG. 6, as in the previous embodiments, if the measurement time required to detect the low-speed running state cannot be secured, the frame control signal (FCMC) is stored. This can be dealt with by controlling the mobile station device with the control information (FIG. 8) and increasing the cycle of assigning the activation slot (ACTS) to the communication frame and the cycle of repeating the connection request signal (ACTC). As for the trigger for determining whether or not communication connection is possible, the connection request signal (ACTC) is newly received without providing the input terminal 7 for the determination request signal C as in the previous embodiments. It is also possible to enter a communication connection availability determination operation.

It is a block block diagram which shows 1st Embodiment of the base station apparatus of the narrow area communication system by this invention. It is a flowchart which shows 1st Embodiment of the availability determination method of the connection request | requirement with the mobile station apparatus of the base station of the narrow area communication system by this invention. It is a flowchart which shows 2nd Embodiment of the availability determination method of the connection request | requirement with the mobile station apparatus of the base station of the narrow area communication system by this invention. It is a block block diagram which shows 2nd Embodiment of the base station apparatus of the narrow area communication system by this invention. It is a flowchart which shows 3rd Embodiment of the availability determination method of the connection request | requirement with the mobile station apparatus of the base station of the narrow area communication system by this invention. It is a flowchart which shows 4th Embodiment of the availability determination method of the connection request | requirement with the mobile station apparatus of the base station of the narrow area communication system by this invention. It is a figure which shows the specific structural example of a communication frame. It is a figure which shows the specific structural example of the frame control signal in the slot for control in FIG. It is a figure which shows the specific structural example of the activation slot in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna 2, 2 'Modulation / demodulation means 3, 3' Communication connection determination means 4 Communication management means 5 Communication control means 6 Application processing means 7 Input terminal

Claims (4)

In a base station apparatus of a narrow area communication system that is installed on the road and performs wireless communication with a mobile station apparatus mounted on a vehicle,
Comprising at least communication connection determination means for determining whether or not communication connection with the mobile station apparatus is possible based on a connection request signal for requesting the base station apparatus to perform communication connection transmitted by the mobile station apparatus;
The communication connection determination means is a predetermined value calculated from the number of receptions of the connection request signal counted within a predetermined time determined in advance , the size of the communication area determined for the base station device, and the vehicle speed. from comparison result between the reception times of the threshold value was, the mobile station when the said purpose which determines the purpose of the entry into the communication area of the vehicle, the received number corresponds to or higher than the threshold of the received number is discriminated A base station apparatus of a narrow-area communication system, characterized in that it determines whether to accept a communication connection request from an apparatus. In a base station apparatus of a narrow area communication system that is installed on the road and performs wireless communication with a mobile station apparatus mounted on a vehicle,
Comprising at least communication connection determination means for determining whether or not communication connection with the mobile station apparatus is possible based on a connection request signal for requesting the base station apparatus to perform communication connection transmitted by the mobile station apparatus;
The communication connection determination means includes
The number of times of reception of the connection request signal counted within a predetermined time determined in advance, and a threshold of a predetermined number of times of reception calculated from the size of the communication area determined for the base station apparatus and the speed of the vehicle From the comparison result, the purpose of entering the communication area of the vehicle is determined, and the integrated reception level obtained by sequentially integrating the reception levels indicating the signal strength of the connection request signal for which the number of receptions is counted is divided by the number of receptions. The connection request signal to be counted is moved within the communication area based on the comparison result between the average reception level and the threshold value of the average reception level that is the lower limit value of the reception intensity of the connection request signal determined by the base station device as the communication area. Determine whether it is a connection request signal from the station device,
When the purpose corresponding to the reception frequency equal to or greater than the reception frequency threshold is determined and a determination result indicating that the connection request signal is from the mobile station device in the communication area is obtained A base station apparatus of a narrow area communication system, characterized in that it determines whether to accept a communication connection request from a station apparatus. In a method for determining whether or not a communication connection is established with a mobile station device of a base station device of a narrow area communication system that is installed on a road and wirelessly communicates with a mobile station device mounted on a vehicle,
  Each time a connection request signal for requesting the base station apparatus to make a communication connection transmitted by the mobile station apparatus is received within a predetermined time, the step of counting the number of times the received connection request signal is received;
  Comparing the counted number of receptions with a predetermined reception number threshold calculated from the size of the communication area defined in the base station apparatus and the speed of the vehicle;
  A step of accepting a communication connection request from the mobile station apparatus when the reception count is equal to or greater than the threshold;
  A method for determining whether or not a communication connection with a mobile station apparatus of a base station apparatus of a narrow area communication system is provided. In a method for determining whether or not a communication connection is established with a mobile station device of a base station device of a narrow area communication system that is installed on a road and wirelessly communicates with a mobile station device mounted on a vehicle,
Each time a connection request signal for requesting the base station apparatus to make a communication connection transmitted by the mobile station apparatus is received within a predetermined time, the step of counting the number of times the received connection request signal is received;
Comparing the counted number of times of reception with a predetermined number of times of reception calculated from the size of the communication area determined in the base station device and the speed of the vehicle ;
Integrating the reception level value indicating the signal strength of the connection request signal from which the number of receptions is counted, and dividing the integrated reception level value by the number of receptions to obtain an average reception level value;
The reception frequency is equal to or greater than a predetermined threshold value of the reception frequency, and the average reception level value is equal to or greater than an average reception level threshold value which is a lower limit value of the reception strength of a connection request signal determined by the base station device as a communication area. And a step of accepting a communication connection request from the mobile station apparatus. A method for determining whether or not communication connection with a mobile station apparatus of a base station apparatus of a narrow area communication system is possible.

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