JP6023644B2 - Wireless communication system, wireless communication method, and moving object detection system - Google Patents

Description

  The present invention relates to a wireless communication system, a wireless communication method, and a moving body detection system.

  Conventionally, even when a plurality of reader / writers for communicating with RFID (Radio Frequency IDentification) tags are arranged close to each other, communication caused by radio wave interference between the reader / writers. There is a technique that enables the occurrence of a failure to be suppressed in a state in which good communication quality is ensured (see, for example, Patent Document 1).

  In the wireless communication system described in Patent Document 1, a system controller sequentially instructs a plurality of reader / writers to transmit a test signal having a default output level composed of an unmodulated signal, and the test signal is received from the reader / writer. When the signal is transmitted, the reception level of the test signal measured by another reader / writer is collected. If the collected reception level exceeds a preset non-interference level, the transmission level of the reader / writer that is the test signal transmission source enters the reader / writer and its communication area. The transmission level can be reduced within a range that does not fall below the minimum transmission level required for communication with the RFID tag. However, there is a feature that the communication area is narrowed to suppress the transmission output of the reader / writer.

JP 2007-124321 A

  By the way, when the wireless communication system described in Patent Document 1 is used, there is a demand for accurately detecting the traveling direction and position of a receiver (corresponding to the RFID tag of Patent Document 1). FIG. 25 is a diagram illustrating a configuration of a wireless communication system according to a conventional technique. When a zone A that is a communicable area of the transmitter A (corresponding to the reader / writer of Patent Document 1) and a zone B that is a communicable area of the transmitter B are formed, as shown in FIG. When C crosses zone A and zone B, it crosses the zone (zone A と B) where zone A and zone B intersect. In order to accurately detect the traveling direction and position of the receiver C, it is desirable that the zone A, the zone B, and the zone (A∩B) can be distinguished.

  However, in the conventional wireless communication system, when the transmitter A and the transmitter B transmit alternately so as not to interfere, the data of the transmitter A or the transmitter B is received in the zone (A∩B). Therefore, the received data at the receiver C may become “data of the transmitter A”, “data of the transmitter B”, “data of the transmitter A”, “data of the transmitter B”, and the traveling direction is detected. There is a problem that you can not.

  FIG. 26 is a diagram illustrating data reception timing in asynchronous transmission. As shown in FIG. 26, when the transmitter A and the transmitter B are in an asynchronous operation, there is a time zone in which a collision occurs between the data signal of the transmitter A and the data signal of the transmitter B. There is also a problem that it cannot be received.

  FIG. 27 is a diagram illustrating a configuration of a wireless communication system when a zone is reduced. As shown in FIG. 27, if the zones A and B are configured not to overlap each other so as not to cause a collision between the two signals, an area where signals cannot be received increases, which is not desirable.

  The present invention has been made in view of such circumstances, and a wireless communication system and a wireless communication method capable of accurately detecting the traveling direction and position of the receiver without reducing the communicable area (zone). And it aims at providing the mobile body detection system using a radio | wireless communications system.

  The present invention provides a plurality of transmitters installed at predetermined positions and wirelessly transmitting their own identification information within a predetermined communicable area, and receiving the identification information from each of the transmitters. A wireless communication system comprising a receiver that detects a position and a moving direction, wherein the communicable area of the transmitter has an area that overlaps the communicable area of the adjacent transmitter, and the receiver Detecting the position and moving direction of the device by discriminating between a region where the communicable regions do not overlap and a region where the communicable regions overlap.

  In the present invention, the transmitter transmits the identification information in such a manner that the transmitters in which the communicable areas overlap each other transmit the identification information, and the receiver transmits two of the identifications within a predetermined time. When each piece of information is received, it is determined that its own position is an area where the communicable areas overlap each other.

  In the present invention, the transmitter transmits the identification information so that the transmitters in which the communicable areas overlap each other coincide with the timing at which the identification information is transmitted, and the receiver transmits the identification information within a predetermined time. When the mobile phone cannot be received, it is determined that its own position is a region where the communicable regions overlap each other.

  In the present invention, the transmitter transmits the identification information using a different time slot determined in advance for each transmitter, and the receiver receives the identification information in two time slots at a predetermined time. When it is possible, the self-position is determined to be an area where the communicable areas overlap each other.

  The present invention transmits its own identification information within a predetermined communicable area, and receives a plurality of transmitters respectively installed at predetermined positions and the identification information from each of the transmitters. A wireless communication method performed by a wireless communication system including a receiver that detects a position and a moving direction, wherein the communicable area of the transmitter has an area overlapping with the communicable area of the adjacent transmitter. The receiver has a step of detecting an own position and a moving direction by discriminating an area where the communicable areas do not overlap and an area where the communicable areas overlap.

  The present invention is characterized in that the receiver in the wireless communication system is mounted on a moving body, and the position and moving direction of the moving body are detected.

  According to the present invention, it is possible to accurately detect the traveling direction and position of the receiver without reducing the communicable area (zone).

It is a block diagram which shows the structure of 1st Embodiment of this invention. It is a figure which shows allocation of the time slot in the transmitters A and B shown in FIG. 3 is a flowchart illustrating an operation in which the computer 3 illustrated in FIG. 1 estimates the position of a receiver C. It is a figure which shows the table structure of the management table referred when estimating the position of the receiver C. FIG. It is a flowchart which shows the operation | movement which the computer 3 judges the position which the receiver C moved. It is a figure which shows the table structure of the storage data referred when the computer 3 judges the position which the receiver C moved. It is a block diagram which shows the structure of 2nd Embodiment of this invention. It is a figure which shows allocation of the time slot in the transmitters A and B shown in FIG. It is a flowchart which shows operation | movement of the receiver C shown in FIG. It is a flowchart which shows the operation | movement which the computer 3 shown in FIG. 7 grasps | ascertains the position of the receiver C from received data. It is a figure which shows the table structure of the management table referred when the computer 3 grasps | ascertains the position of the receiver C from received data. It is a flowchart which shows the operation | movement which the calculator 3 estimates the position which the receiver C moved. It is a figure which shows the table structure of the place state transition table referred when estimating the position which the receiver C moved. It is a figure which shows the table structure of the storage data referred when estimating the position which the receiver C moved. It is a block diagram which shows the structure of 3rd Embodiment of this invention. Time slot allocation in transmitters A and B shown in FIG. 15 will be described. 16 is a flowchart showing an operation of the receiver C shown in FIG. It is a flowchart which shows the operation | movement which the computer 3 shown in FIG. 15 grasps | ascertains the position of the receiver C from received data. It is a figure which shows the table structure of the management table referred when the computer 3 grasps | ascertains the position of the receiver C from received data. It is a figure which shows the table structure of the place conversion table referred when the computer 3 grasps | ascertains the position of the receiver C from received data. It is a flowchart which shows the operation | movement which the calculator 3 estimates the position which the receiver C moved. It is a figure which shows the table structure of the storage data referred when estimating the position which the receiver C moved. It is a figure which shows the timing at the time of performing time division transmission so that it may not collide. It is a figure which shows the timing at the time of performing the transmission which produces a collision intentionally. It is a figure which shows the structure of the radio | wireless communications system by a prior art. It is a figure which shows the timing of the data reception in asynchronous transmission. It is a figure which shows the structure of the radio | wireless communications system at the time of shrinking | reducing a zone.

<First Embodiment>
Hereinafter, a wireless communication system according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment. In this figure, symbols A and B are transmitters that perform signal transmission by wireless communication. The transmitters A and B each have a communicable area (referred to as a zone). Here, the communicable area of the transmitter A is zone A, and the communicable area of the transmitter B is zone B. Symbol C is a receiver that is provided in the mobile body and receives signals transmitted from the transmitters A and B. Symbol D is a timer event generator that generates an event at a predetermined period and outputs the event to each of the transmitters A and B. Reference numeral 1 denotes a transmitter that is provided in the mobile body and performs signal transmission by wireless communication. Reference numeral 2 denotes a receiver that receives a signal transmitted from the transmitter 1. Reference numeral 3 denotes a computer (computer) that performs processing for estimating the position of the receiver 1 (moving body) based on the signal received by the receiver 2.

  Next, with reference to FIG. 2, time slot allocation in transmitters A and B shown in FIG. 1 will be described. FIG. 2 is a diagram showing time slot allocation in transmitters A and B shown in FIG. The timer event generator D generates an event every certain period T0 (for example, 500 ms), and notifies the transmitter A and the transmitter B of the event. The transmitter A that has received the event immediately transmits the data including the preamble and the location information of the transmitter A during the time th and by the radio immediately. Similarly, the transmitter B wirelessly transmits data including a preamble, an identifier of the transmitter B, and location information after a certain time td has elapsed (for example, after 100 ms). The identifier may also serve as location information.

  The frequency band of the transmitter 1 is different from that of the transmitters A and B. The “communication distance between the transmitter A or B and the receiver C” and the “communication distance between the transmitter 1 and the receiver 2” are selected so that the latter is sufficiently longer. The receiver C has a function of receiving data from the transmitter A and data from the transmitter B, and a function of measuring the reception intensity of the received data. The transmitter 1 collects the data including the identifier and location information of the transmitter A or B received by the receiver C, the measured reception intensity, and the identifier of the transmitter 1 into one data and transmits the data to the receiver 2. The receiver 2 is connected to the computer 3, receives a signal sent from the transmitter 1, and transfers it to the computer 3. The computer 3 grasps the position of the receiver C (position of the moving body) and determines the position where the receiver C has moved.

  Next, the operation of the computer 3 shown in FIG. 1 estimating the position of the receiver C will be described with reference to FIGS. FIG. 3 is a flowchart illustrating an operation in which the computer 3 illustrated in FIG. 1 estimates the position of the receiver C. FIG. 4 is a diagram illustrating a table structure of a management table that is referred to when the position of the receiver C is estimated.

  First, the computer 3 receives data from the receiver 2 (step S1). The management table shown in FIG. 4 is stored in the computer 3. Then, the computer 3 determines whether or not the identifier included in the received data is in the management table (FIG. 4) (step S2). If the identifier included in the data is not in the management table as a result of this determination, the computer 3 registers the identifier, the location state, and the reception strength in the management table, and sets 0 as the update time (step S3).

  Next, when the identifier included in the data is in the management table, the computer 3 determines whether or not the location information included in the data is different from the location state in the management table (step S4). As a result of this determination, if the location information included in the data is not different from the location status of the management table, the computer 3 changes the reception strength of the corresponding identifier in the management table and sets the update time to 0 (step S5). .

  Next, when the location information included in the data is different from the location status in the management table, the computer 3 determines whether the reception intensity is equal to or less than the reference value and the update time is equal to or less than the period T0 (step S6). As a result of this determination, when the reception intensity is less than the reference value and the update time is not less than the period T0, the computer 3 changes the location state and reception intensity to the location information and reception intensity included in the data, and sets the update time to 0. (Step S7).

  Next, when the reception intensity is equal to or less than the reference value and the update time is equal to or less than the period T0, the computer 3 regards the current location as the intersection (A∩B) between the zone A and the zone B (step S8). Then, the computer 3 changes the place state to “intersection of place”, changes the reception intensity to the reference value, and sets the update time to 0 (step S9).

  Next, with reference to FIG. 5 and FIG. 6, the operation in which the computer 3 determines the position where the receiver C has moved will be described. FIG. 5 is a flowchart showing an operation in which the computer 3 determines the position where the receiver C has moved. FIG. 6 is a diagram showing a table structure of stored data that is referred to when the computer 3 determines the position where the receiver C has moved. First, the computer 3 reads the location state from the management table and the storage data (FIG. 6), and if there is no corresponding storage data, adds an identifier and sets the location state before the change to NULL (step S11). Then, the computer 3 determines whether or not the place state has changed (step S12). If the result of this determination is that the location state has changed, the computer 3 notifies that it has moved from the location state of the stored data to the location state of the management table (step S13). On the other hand, if the location state has not changed, step S13 is not executed.

  Next, the computer 3 copies the identifier and location status of the management table to the stored data, and adds a sleep time to the update time for each identifier of the management table (step S14). Then, the computer 3 determines whether or not the update time has exceeded the specified time (step S15). As a result of the determination, if the update time does not exceed the specified time, the process waits for a predetermined sleep time (step S16) and returns to step S11. On the other hand, if the update time exceeds the specified time, the computer 3 deletes the data of the corresponding identifier from the management table and the stored data (step S17). Then, the computer 3 waits for a predetermined sleep time (step S16) and returns to step S11.

Second Embodiment
Next, a radio communication system according to the second embodiment of the present invention will be described. FIG. 7 is a block diagram showing the configuration of the embodiment. In this figure, the same parts as those in the apparatus shown in FIG. Here, with reference to FIG. 8, time slot allocation in transmitters A and B shown in FIG. 7 will be described. FIG. 8 is a diagram showing time slot allocation in transmitters A and B shown in FIG. The timer event generator D generates an event every certain period (for example, 500 ms) and notifies the transmitter A and the transmitter B of the event. Transmitters A and B that have received the event immediately transmit radio. In FIG. 8, time Th transmits data including a preamble, and time Tw transmits data including an identifier and location information of a wireless transmitter. The identifier may also serve as location information.

  The receiver C transmits to the receiver C via the transmitter C information indicating that the signal has been received from the transmitter A when the signal of the transmitter A is received when entering the zone A. Further, when entering the zone A∩B, it is determined whether the radio reception level is equal to or higher than a specified value. If the level is equal to or higher than the specified value, information indicating that the receiver C exists in the overlapped zone is sent to the transmitter 1. To the receiver 2. When the receiver C enters the zone B, information indicating that the signal has been received from the transmitter B is transmitted to the receiver 2 via the transmitter 1 when the signal of the transmitter B is received.

  Next, the operation of the receiver C shown in FIG. 7 will be described with reference to FIG. FIG. 9 is a flowchart showing the operation of the receiver C shown in FIG. First, the receiver C turns itself on (sets to a receivable state) in a Th / 2 cycle (step S21). And the receiver C determines whether it received (step S22). As a result of the determination, if not received, the receiver C turns itself off (a state in which reception is not possible) (step S23) and returns to step S21.

  On the other hand, when receiving, the receiver C postpones the ON time by the period T0 (step S24). Then, the receiver C determines whether or not the reception is finished (step S25). If reception is not completed as a result of the determination, the receiver C determines whether or not the period T0 has been exceeded (step S26). As a result of this determination, if it does not exceed, the process returns to step S25, and if it exceeds, the process returns to step S23.

  Next, when the reception is completed, the receiver C checks whether or not the identifier (and location information) of the wireless transmitter can be determined from the received data (step S27). If it is determined as a result of the confirmation, the receiver C adds its own identifier and transmits the received data and the received intensity from the transmitter 1 (step S28). On the other hand, if the determination cannot be made, the receiver C transmits the data indicating that the zones overlap with the addition of its own identifier and the reception intensity from the transmitter 1 (step S29). The receiver C repeatedly executes the process shown in FIG.

  Next, an operation in which the computer 3 shown in FIG. 7 grasps the position of the receiver C from the received data will be described with reference to FIGS. FIG. 10 is a flowchart showing an operation in which the computer 3 shown in FIG. 7 grasps the position of the receiver C from the received data. FIG. 11 is a diagram illustrating a table structure of a management table that is referred to when the computer 3 grasps the position of the receiver C from the received data.

  First, the computer 3 receives data from the receiver 2 (step S31). Then, the computer 3 determines whether or not the identifier included in the received data is in the management table (FIG. 11) (step S32). As a result of this determination, when the identifier included in the data does not exist in the management table, the computer 3 determines whether or not the received data includes location information (step S33).

  If the location information is not included in the data as a result of this determination, the computer 3 registers the identifier and the reception strength in the management table, sets 0 for the update time, and indefinite for the location information (step S34), and step S31. Return to. On the other hand, if the location information is included in the data, the computer 3 registers the identifier, the location state, and the reception strength in the management table, sets 0 as the update time (step S35), and returns to step S31.

  Next, when the identifier included in the data is in the management table, the computer 3 determines whether or not the location information is included in the received data (step S36). When the location information is included in the data as a result of this determination, the computer 3 overwrites the location state and reception intensity acquired from the received data in the data string of the corresponding identifier, and sets the update time to 0 (step S37), the process returns to step S31. On the other hand, when the location information is not included in the data, the computer 3 determines whether or not the reception intensity is greater than or equal to the threshold (step S38). If the result of this determination is not greater than or equal to the threshold value, the computer 3 registers the reception strength in the data string of the corresponding identifier in the management table, sets 0 for the update time, and indefinite for the location information (step S39). Return to S31. On the other hand, if it is equal to or greater than the threshold value, the computer 3 registers the reception intensity in the data string of the corresponding identifier in the management table, sets 0 for the update time, and “boundary” for the location information (step S40), and step S31. Return to.

  Next, with reference to FIGS. 12, 13, and 14, the operation in which the computer 3 estimates the position where the receiver C has moved will be described. FIG. 12 is a flowchart showing an operation in which the computer 3 estimates the position where the receiver C has moved. FIG. 13 is a diagram illustrating a table structure of a place state transition table that is referred to when the position where the receiver C has moved is estimated. FIG. 14 is a diagram illustrating a table structure of stored data that is referred to when the position where the receiver C has moved is estimated. First, the computer 3 reads the location state from the management table (FIG. 13) and the storage data (FIG. 14), and if there is no corresponding storage data, the location state of the storage data is regarded as indefinite and creates storage data (step S51). ). Then, the computer 3 determines whether or not the location state of the management table and the location state of the storage data have changed (step S52). If the result of this determination is that the location state of the management table and the location state of the stored data have changed, the computer 3 performs processing based on the location state transition table (step S53).

  Next, the computer 3 copies the location state of the storage data to the state before change and the location state of the management table to the storage data location state (step S54). If the location state of the management table and the location state of the storage data are not changed, steps S53 and S54 are not executed. And the computer 3 adds sleep time to the update time with respect to the identifier of a management table (step S55).

  Next, the computer 3 determines whether or not the update time exceeds the specified time (step S56). As a result of this determination, if the update time does not exceed the specified time, the computer 3 waits for Sleep time and returns to Step S51. On the other hand, if the update time exceeds the specified time, the computer 3 deletes the data of the corresponding identifier from the management table and the stored data (step S58), waits for Sleep time, and returns to step S51.

<Third Embodiment>
Next, a radio communication system according to a third embodiment of the present invention is described. FIG. 15 is a block diagram showing the configuration of the embodiment. In this figure, the same parts as those in the apparatus shown in FIG. Here, with reference to FIG. 16, time slot allocation in transmitters A and B shown in FIG. 15 will be described. FIG. 16 is a diagram showing time slot allocation in transmitters A and B shown in FIG. The timer event generator D generates an event every certain period Tc (for example, 100 ms), and notifies the wireless transmitter A and the wireless transmitter B of the event. The transmitter A that has received the event immediately transmits the carrier wirelessly for the time th, and transmits the carrier for the time tw at the head of the determined time slot (for example, time slot 0). On the other hand, the transmitter B immediately transmits the carrier by radio for the time th, and transmits the carrier for the time tw at the beginning of a determined time slot (eg, time slot 1) different from the time and lot of the transmitter A.

  The receiver 1 determines in which time slot the carrier is detected, and the transmitter C transmits the identifier of the transmitter C and the information in which time slot the receiver 1 detects the carrier. The receiver C receives the data from the transmitter C and transfers it to the computer 3. Here, the operation of the receiver C shown in FIG. 15 will be described with reference to FIG. FIG. 17 is a flowchart showing the operation of the receiver C shown in FIG. First, the receiver C turns itself on (sets to a receivable state) in the Th / 2 cycle (step S61). And the receiver C determines whether it received (step S62). As a result of this determination, if not received, the receiver C turns itself off (a state in which reception is not possible) (step S63), and returns to step S61.

  On the other hand, when receiving, the receiver C postpones the ON time by the period Tc (step S64). Then, the receiver C determines whether or not Th / 2 or more has been continuously received (step S65). If reception is not completed as a result of the determination, the receiver C determines whether or not the period Tc has been exceeded (step S66). As a result of this determination, if it does not exceed, the process returns to step S65, and if it exceeds, the process returns to step S63.

  Next, if not continuously receiving Th / 2 or more, the receiver C delays its own ON time by the period Tc, detects the end of Th, and recognizes the time slot (step S67). Then, the receiver C detects the presence / absence of data for each time slot (step S68), and transmits the identifier of the transmitter 1 and the data presence / absence information for each time slot to the receiver 2 using the transmitter 1 (step S68). Step S69).

  Next, with reference to FIGS. 18, 19, and 20, an operation in which the computer 3 grasps the position of the receiver 1 from the received data will be described. FIG. 18 is a flowchart showing an operation in which the computer 3 shown in FIG. 15 grasps the position of the receiver C from the received data. FIG. 19 is a diagram showing a table structure of a management table that is referred to when the computer 3 grasps the position of the receiver C from the received data. FIG. 20 is a diagram showing a table structure of a place conversion table that is referred to when the computer 3 grasps the position of the receiver C from the received data.

  First, the computer 3 receives data from the receiver 2 (step S71). Then, the computer 3 determines whether or not the identifier included in the received data is in the management table (step S72). If the identifier included in the data is not in the management table as a result of this determination, the computer 3 registers a new identifier in the management table (FIG. 19) (step S73). On the other hand, when the identifier included in the data is in the management table, the computer 3 converts the data presence / absence information for each time slot of the received data and the location conversion table (FIG. 20) into the location, and converts it to the management table (FIG. 19). Register and set the update time to 0 (step S74).

  Next, with reference to FIG. 21 and FIG. 22, the operation in which the computer 3 estimates the position where the receiver C has moved will be described. FIG. 21 is a flowchart showing an operation in which the computer 3 estimates the position to which the receiver C has moved. FIG. 22 is a diagram illustrating a table structure of stored data that is referred to when the position where the receiver C has moved is estimated. First, the computer 3 reads the location state from the management table and the storage data (FIG. 22), and if there is no corresponding storage data, adds an identifier and sets the location state before the change to NULL (step S81). Then, the computer 3 determines whether or not the location state of the management table and the location state of the storage data have changed (step S82). As a result of the determination, if the location state of the management table and the location state of the storage data have not changed, the process returns to step S81. On the other hand, if the location status of the management table and the location status of the storage data have changed, the computer 3 notifies that the location status before the change of the storage data has moved to the location status of the management table (step S83).

  Next, the computer 3 copies the management table identifier and the location state to the stored data, and adds a sleep time to the update time for the management table identifier (step S84). Then, the computer 3 determines whether or not the update time has exceeded the specified time (step S85). If the update time does not exceed the specified time as a result of this determination, the computer 3 waits for Sleep time (step S86) and returns to step S81. On the other hand, if the update time exceeds the specified time, the computer 3 deletes the data of the corresponding identifier from the management table and the stored data (step S87), waits for Sleep time (step S86), and returns to step S81. .

  As described above, the timings of the transmitter A and the transmitter B are synchronized, and the transmitter A and the transmitter B are time-divisionally transmitted so that the transmitter A and the transmitter B do not collide as shown in FIG. Can be detected simultaneously, it can be detected that the receiver C is located at the intersection (A ゾ ー ン B) of the zone A and the zone B. FIG. 23 is a diagram illustrating timing when performing time division transmission so as not to collide.

  In addition, as shown in FIG. 24, the transmitter A and the transmitter B are transmitted so as to collide, and the data that cannot be interpreted by the receiver when the data of the transmitter A and the transmitter B collide is received. Thus, it can be detected that the receiver C is located at the intersection (A ゾ ー ン B) of the zone A and the zone B. FIG. 24 is a diagram illustrating timing when transmission that intentionally causes a collision is performed.

  In addition, it is possible to detect that the receiver C is located at the intersection (A∩B) of the zone A and the zone B by applying a modulation method that is strong against collisions such as pulse position modulation and spreading code. it can.

  As a result, it is possible to estimate the area (zone) in detail, and it is possible to easily estimate the traveling direction of the receiver C and the like.

  The processing operations in the transmitters A and B, the receiver C, the transmitter 1 and the receiver 2 in the above-described embodiment may be realized by a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in the computer system. It may be realized using hardware such as PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array).

  As mentioned above, although embodiment of this invention has been described with reference to drawings, the said embodiment is only the illustration of this invention, and it is clear that this invention is not limited to the said embodiment. is there. Accordingly, additions, omissions, substitutions, and other changes of the components may be made without departing from the technical idea and scope of the present invention.

  The present invention can be applied to applications in which it is indispensable to accurately detect the traveling direction and position of the receiver without reducing the communicable area (zone).

  A, B ... Transmitter, C ... Receiver, D ... Timer event generator, 1 ... Transmitter, 2 ... Receiver, 3 ... Computer

Claims (3)

A plurality of transmitters each installed at a predetermined position and wirelessly transmitting its own identification information within a predetermined communicable area;
Receiving the identification information from each of the transmitters, a wireless communication system comprising a receiver that detects its own position and moving direction,
The communicable area of the transmitter has an area overlapping with the communicable area of the adjacent transmitter,
The transmitter transmits the identification information so that transmitters in which the communicable areas overlap each other match the timing at which the identification information is transmitted,
When the receiver is unable to receive the identification information within a predetermined time, the receiver determines that the position is an area where the communicable areas overlap each other, so that the communicable areas do not overlap, and the communication A wireless communication system, characterized in that a self-position and a moving direction are detected by discriminating an area where possible areas overlap. A plurality of transmitters each installed at a predetermined position and wirelessly transmitting its own identification information within a predetermined communicable area;
A wireless communication method performed by a wireless communication system including a receiver that detects its own position and moving direction by receiving the identification information from each of the transmitters,
The communicable area of the transmitter has an area overlapping with the communicable area of the adjacent transmitter,
The transmitter transmits the identification information such that transmitters in which the communicable areas overlap each other match the timing at which the identification information is transmitted;
When the receiver cannot receive the identification information within a predetermined time, the receiver determines that the communicable area is an area where the communicable areas overlap each other, so that the communicable areas do not overlap, and the communication area of overlap to determine the area, a wireless communication method characterized by a step of detecting a moving direction and its location. A mobile body detection system comprising the wireless communication system according to claim 1 , wherein the receiver is mounted on a mobile body, and a position and a moving direction of the mobile body are detected.

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