JP2010130133A - Radio communication terminal, and radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication terminal and a radio communication system, capable of preventing a cut and return phenomenon where changeover of a base station is repeated multiple times, and providing seamless radio communication. <P>SOLUTION: This radio communication terminal Y mounted on a vehicle 1 moving on a predetermined track L and executing radio communication with any one of a plurality of base stations (for instance, A-C) installed along the track L is configured to read a plurality of signs 31-33 (marks) installed at a plurality of preset positions along the track L based on a landscape image picked up by a landscape imaging means for picking up a landscape from the vehicle 1, and changes over the base station for executing the radio communication in response to the reading result. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication system in which a wireless communication terminal performs wireless communication with any one of a plurality of base stations, and more particularly to a base station to which wireless communication is established while the wireless communication terminal is moving. The present invention relates to a so-called handover processing technique executed for switching.

In general, in a wireless communication network such as a wireless LAN or a wireless MAN, a wireless communication terminal performs a so-called handover process in which one base station is selected from a plurality of base stations while moving and a wireless communication establishment destination is switched. It is known to do. In such a handover process, when a wireless communication terminal is communicating with a certain base station while moving, if the field strength of communication with the base station falls below the lower threshold, the next base station starts to be searched. Specifically, a base station having the highest electric field strength (synonymous with radio signal strength) is selected from a plurality of base stations that can currently communicate, and wireless communication with the base station is established. However, in such a handover process, a switching phenomenon may occur in which switching between two base stations is repeated a plurality of times due to fluctuations in electric field strength due to a temporary change in the radio wave propagation environment.
Therefore, it is conceivable to change the communication destination base station according to the current position of the wireless communication terminal instead of the electric field strength. Thereby, the above switching phenomenon can be prevented. The current position of the moving vehicle can be specified based on position information received by the GPS receiver of the car navigation device, as disclosed in, for example, Patent Document 1.
JP 2006-262175 A

However, when a GPS receiver is used, there arises a problem that the current position of the vehicle cannot be specified in a situation where the position information cannot be acquired by a GPS receiver such as underground or in a tunnel. In addition, on roads and tracks sandwiched between high-rise buildings, there is a problem that the number of GPS sanitations that can capture a vehicle decreases, and the error in the position information of the vehicle increases.
As described above, in the position identification method using the GPS receiver, the current position of the vehicle may not be accurately identified depending on the situation, and the base station cannot be switched appropriately, and wireless communication is temporarily performed. There is a risk of interruption.
Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is to prevent a switching back phenomenon in which switching of base stations is repeated a plurality of times and to realize seamless wireless communication. To provide a wireless communication terminal and a wireless communication system.

In order to achieve the above object, the present invention is mounted on a moving body that moves on a predetermined trajectory, and between any one of the plurality of base stations installed along the trajectory. A plurality of positions that are applied to a wireless communication terminal that performs wireless communication, and that are set in advance along the trajectory based on a landscape image captured by a landscape image capturing unit that captures a landscape from the moving object. A wireless communication terminal comprising: a mark reading means for reading a plurality of marks installed in a base station; and a base station switching means for switching the base station for performing wireless communication according to a reading result by the mark reading means. Configured as
In the wireless communication terminal configured as described above, the base station is switched by the base station switching unit according to the result of reading by the mark reading unit for each of a plurality of preset positions. Thus, it is possible to reliably avoid the switching back phenomenon that has occurred in the conventional configuration in which switching of the base station is determined. Also, since the current position of the moving body is specified by reading each of the landmarks installed on the trajectory on which the moving body moves, unlike the case where the position is determined using a GPS receiver, The position of the body can be reliably identified without error. It should be noted that the installation positions of each of the landmarks and each of the base stations are based on experiments and simulations performed in advance so that a sufficient electric field strength can be secured in the radio communication between the radio communication terminal and each of the base stations. Set it up.

By the way, since the processing for detecting the presence / absence of the landmark is large for the entire landscape image photographed by the landscape photographing means, the landmark reading means is determined in advance among the landscape images photographed by the landscape photographing means. It is desirable to read the presence / absence of the above-mentioned mark in the partial area. As a result, for example, the processing load related to image processing such as the above-described mark matching processing is reduced.
Further, the base station switching means can be considered as one example that switches the plurality of base stations in the order of travel of the mobile body each time the mark is read by the mark reading means. Thereby, it is possible to sequentially switch to the base station corresponding to the position where the mark is read.

Furthermore, correspondence information storage means for storing correspondence information in which identification information of each of the plurality of landmarks is associated with identification information of each of the plurality of base stations is provided, and the base station switching means is configured to read the landmarks. It is also conceivable to switch to the base station corresponding to the mark based on the identification information of the mark read by the means and the correspondence information stored in the correspondence information storage means. According to this configuration, it is possible to maintain the correspondence between each of the landmarks and each of the base stations. For example, even when the mark has been skipped for some reason, it is possible to switch to the base station corresponding to the position of the mark when reading the mark.
In this configuration, each of the marks includes a first mark common to each of the marks and a second mark for identifying each of the marks, and the mark reading means includes the first mark. More preferably, the second mark is read on condition that the mark 1 is read. Thereby, since the said mark reading means should just perform the process for detecting said common 1st mark about each said landscape image first, said 2nd mark different for every said mark about each said landscape image The processing load can be reduced as compared with the case where the process for detecting is always executed.

  By the way, the present invention may be understood as an invention of a wireless communication system including the wireless communication terminal. Specifically, the present invention comprises a wireless communication terminal mounted on a moving body that moves on a predetermined orbit and a plurality of base stations installed along the orbit, and the wireless communication terminal And a landscape photographing means for photographing a landscape from the moving body, and the trajectory, which is applied to a wireless communication system that performs wireless communication with any one of the plurality of base stations According to a plurality of landmarks installed at a plurality of preset positions, a landmark reading means for reading the landmarks based on a landscape image photographed by the landscape photographing means, and a reading result by the landmark reading means And a base station switching means for switching the base station that performs wireless communication.

  According to the present invention, since the base station is switched by the base station switching means according to the reading result by the mark reading means for each of a plurality of preset positions, the base station is switched based on the electric field strength. It is possible to reliably avoid the switch-back phenomenon that has occurred in the conventional configuration that has been determined. Also, since the current position of the moving body is specified by reading each of the landmarks installed on the trajectory on which the moving body moves, unlike the case where the position is determined using a GPS receiver, The position of the body can be reliably identified without error.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a schematic diagram showing a schematic configuration of a radio communication system X according to an embodiment of the present invention, and FIG. 2 is a block diagram and a diagram showing a schematic configuration of a radio communication terminal Y according to an embodiment of the present invention. 3 is a diagram illustrating an example of a landscape image captured by the camera 12, and FIG. 4 is a flowchart for explaining an example of a procedure of a handover process executed in the wireless communication terminal Y according to the embodiment of the present invention. .
As shown in FIG. 1, the radio communication system X according to the present embodiment includes a radio communication terminal Y, base stations A to C, signs 31 to 33 (an example of a mark), and the like. In the radio communication system X, radio communication is established between the radio communication terminal Y and any one of the base stations A to C, and radio signals are transmitted and received. As will be described later, in the handover process (see the flowchart of FIG. 4) executed by the wireless communication terminal Y, the wireless communication system X switches the communication destination base station according to the current position of the wireless communication terminal Y. It has the feature in the point.

The wireless communication terminal Y is mounted at the head of a vehicle 1 (an example of a moving body) such as a train or automobile that travels (moves) along a predetermined track L (movement route) such as a track or road. Yes. Here, the right direction in FIG. 1 is the traveling direction of the vehicle 1 and the front of the vehicle 1.
On the other hand, the base stations A to C are arranged along the trajectory L at predetermined intervals. For convenience of explanation, only the base stations A to C are shown in FIG. 1, but similar base stations are arranged at predetermined intervals in the preceding stage of the base station A and the subsequent stage of the base station C. The
The signs 31 to 33 are installed at predetermined positions along the trajectory L. The signs 31 to 33 have predetermined star marks (see FIG. 3). Has been drawn. The star mark is merely an example, and various other shapes can be adopted. Similarly to the base station, a sign is similarly installed at a predetermined position in the preceding stage of the sign 31 and the subsequent stage of the sign 33.

Each of the signs 31 to 33 specifies which of the base stations A to C is a base station to communicate at the current position of the wireless communication terminal Y, and determines an appropriate switching position of the base station. Used to do.
Specifically, the sign 31 indicates that both the electric field strength of radio communication between the radio communication terminal Y and the base station A and the electric field strength of radio communication between the radio communication terminal Y and the base station B are both. It is installed at a position where a sufficiently secured position can be notified to the wireless communication terminal Y.
Similarly, the indicator 32 has sufficient electric field strength for radio communication between the radio communication terminal Y and the base station B and radio signal strength for radio communication between the radio communication terminal Y and the base station C. It is used to notify the secured position. In addition, the sign 33 includes the electric field strength of wireless communication between the wireless communication terminal Y and the base station C, and the wireless communication between the wireless communication terminal Y and the base station (not shown) next to the base station C. It is used to notify a position where both the electric field strength of communication is sufficiently secured.

Next, the wireless communication terminal Y will be described with reference to FIG.
As shown in FIG. 2, the wireless communication terminal Y includes an antenna unit 11 (hereinafter abbreviated as “antenna 11”), a camera 12 (an example of landscape photographing means), and a wireless communication control device 13 (hereinafter “control device 13”). For short).
The antenna 11 includes antenna elements 11a and 11b having directivity in one direction. The antenna 11 is a diversity antenna that preferentially uses one of the antenna elements 11a and 11b that has better radio wave conditions. The antenna element 11b may be omitted unless the purpose is to obtain the diversity effect.
In the antenna 11, the antenna elements 11 a and 11 b are oriented so that the pointing direction is the moving direction of the vehicle 1 (the right direction in FIG. 1). That is, the antenna 11 has radio communication directivity in the moving direction of the radio communication terminal Y mounted on the vehicle 1 moving along the track L.

The camera 12 is disposed at the head of the vehicle 1 and is an analog video camera, a digital video camera, or the like that captures a landscape seen in front of the vehicle 1. 133 is stored. For example, the camera 12 performs shooting at 15 frames / second. In the present embodiment, the camera 12 captures the front of the vehicle 1. However, the present invention is not limited to this, and the rear of the vehicle 1 or the side may be captured.
In the wireless communication terminal Y, the video data captured by the camera 12 is transmitted from the antenna 11 by wireless communication by the control device 13.

  The control device 13 includes a switching hub 131, a wireless device 132, an encoder 133, an image analysis module 134, a connection destination switching module 135, and the like. The control device 13 is not limited to the above hardware, and may include an arithmetic device such as a CPU and various storage devices (RAM, ROM, etc.). In this case, the control device 13 controls the wireless communication terminal Y by executing processing according to the control program stored in the storage device by the arithmetic device.

The encoder 133 has a storage device such as a hard disk drive for storing video taken by the camera 12.
The switching hub 131 forms a plurality of transmission paths in the control device 13. For example, the wireless device 132 and the image analysis module 134 form a transmission path for reading video data stored in the encoder 133.
The wireless device 132 transmits the video stored in the encoder 133 to any of the base stations A to C by wireless communication using the antenna 11. For wireless communication between the wireless communication terminal Y and the base stations A to C, a communication protocol such as TCP / IP is adopted.

The image analysis module 134 performs image processing for analyzing a landscape image taken by the camera 12 stored in the encoder 133. Here, FIG. 3 shows an example of a landscape image photographed by the camera 12. Specifically, the image analysis module 134 includes the signs 31 to 33 in a predetermined analysis area R (an example of a partial area) set in advance in a landscape image captured by the camera 12. Whether or not to do so, and notifies the connection destination switching module 135 of the reading result. Here, the image analysis module 134 when executing such processing corresponds to the mark reading means. 3A shows a case where the marker 31 does not exist in the analysis area R, and FIG. 3B shows a case where the marker 31 exists in the analysis area R.
The connection destination switching module 135 switches a communication destination base station of the wireless communication terminal Y mounted on the vehicle 1 according to the detection result by the image analysis module 134 (see the flowchart of FIG. 4). Execute.

Next, returning to FIG. 1, the schematic configuration of each of the base stations A to C will be described.
Each of the base stations A to C is common in that it includes antenna units 21 and 22 (hereinafter abbreviated as “antennas 21 and 22”) and wireless communication units 23 and 24.
On the other hand, the base station A is connected to the base stations B and C in that the management unit 3 is wired to the wireless communication unit 23 and can perform wired communication with the management unit 3. Different. The base station A may perform wireless communication with the management unit 3. Each of the base stations A to C may be connected to the management unit 3 by wire.
The management unit 3 includes a monitor for displaying an image captured by the camera 12 of the vehicle 1 and a storage device for storing the image.

The antenna 21 is a diversity antenna composed of two antenna elements having directivity in one direction, like the antenna 11. And in the said antenna 21, the two antenna elements are orient | assigned so that a directivity direction may turn into the direction opposite to the moving direction (left direction in FIG. 1) of the said vehicle 1. FIG. That is, the antenna 21 has radio communication directivity in a direction opposite to the moving direction of the radio communication terminal Y mounted on the vehicle 1 moving along the track L. It is to be noted that the antenna 11 is provided on the back of the vehicle 1 and has directivity in the rear, and the antenna 21 has directivity in the traveling direction of the vehicle 1. Is considered. Further, the antenna 11 and the antenna 21 are not limited to those having directivity in one direction, and may be non-directional antennas, antennas having directivity in both left and right directions in FIG.
On the other hand, the antenna 22 is a diversity antenna including, for example, two antenna elements having directivity in both left and right directions. And in the said antenna 22, the two antenna elements are orient | assigned so that a directivity direction may become the bidirectional | two-way (left-right bidirectional in FIG. 1) of the moving direction of the said vehicle 1, and the opposite direction of this moving direction. That is, the antenna 22 has radio communication directivity in the moving direction of the vehicle 1 and in the direction opposite to the moving direction.

The wireless communication units 23 and 24 include control devices such as arithmetic devices such as CPUs and various storage devices. The wireless communication units 23 and 24 execute wireless communication processing using the antennas 21 and 22 by executing processing according to the control program stored in the storage device. Note that the wireless communication units 23 and 24 are wired and can perform wired communication between each other.
In addition, the wireless communication unit 23 transmits a frame called a beacon signal including identification information (for example, MAC address, IP address, etc.) of the base stations A to C from the antenna 21 continuously or periodically. Execute the process. Accordingly, the wireless communication terminal Y can identify the base stations A to C based on the beacon signal transmitted from the wireless communication unit 23. Here, a method will be described in which the wireless communication terminal Y identifies the base stations A to C based on the beacon signal. However, when the frequency channel is different for each of the base stations A to C, the identification is performed according to the frequency channel. May be.

The wireless communication unit 24 performs wireless communication processing for transmitting and receiving wireless signals to and from adjacent base stations using the antenna 22. For example, the radio communication unit 24 of the base station A includes the base station B arranged on the right side of the base station A in FIG. 1 or a base station (not shown) arranged on the left side of the base station A in FIG. Wireless communication with
In the wireless communication system X, base stations other than the base station A connected to the management unit 3 are directly connected to the base station A by the wireless communication unit 24 or indirectly through another base station. By communicating wirelessly, communication with the management unit 3 is performed. For example, when the base station C receives a radio signal transmitted from the radio communication terminal Y, the base station C transmits the radio signal to the management unit 3 via the base stations B and A in order. To do.

Thus, in the wireless communication system X, the wireless communication terminal Y has directivity in the moving direction, and the base stations A to C have directivity in the direction opposite to the moving direction of the wireless communication terminal Y. It is the composition which has. Therefore, for example, when the wireless communication terminal Y establishes wireless communication with the base station A, the wireless signal received from the base station A as the wireless communication terminal Y approaches the base station A The strength of is increased.
However, when the wireless communication terminal Y passes through the base station A, the wireless communication terminal Y suddenly deviates from the direct communication range of the base station A. Therefore, when the wireless communication terminal Y passes through the base station A, the electric field strength from the base station A obtained by the wireless communication terminal Y is predetermined when the wireless communication terminal Y approaches the base station A. It reaches the maximum value at, and then decreases rapidly.

Here, in the present embodiment, the position where the electric field intensity from the base station A obtained by the wireless communication terminal Y is maximum is the installation position P1 of the sign 31 and the electric field intensity from the base station B is the maximum. It is assumed that the position where the sign 32 is installed is the installation position P2, and the position where the electric field intensity from the base station C is the maximum is the installation position P3 of the sign 33.
That is, in the radio communication system X, it is desirable to switch the communication destination base station to the next base station at each of the installation positions P1 to P3. In the present embodiment, the installation positions P1 to P3 of the signs 31 to 33 are used as base station switching positions. However, the positions of the signs 31 to 33 and the camera 12 that captures the signs 31 to 33 are taken. By adjusting the shooting angle, the position of the analysis area R in the landscape image, and the like, the switching position of the base station can be adjusted as appropriate.

Hereinafter, according to the flowchart of FIG. 4, an example of the procedure of the handover process executed in the control device 13 of the wireless communication terminal Y will be described. In FIG. 3, S1, S2,... Represent processing procedure (step) numbers.
In the wireless communication terminal Y, when the handover process is executed, the base station to which wireless communication is established is sequentially switched to the base stations A to C as the vehicle 1 moves.
Thereby, in the wireless communication system X, video data captured by the camera 12 of the wireless communication terminal Y is transmitted to any of the base stations A to C, and the video data is transmitted to the management unit 3. The

First, in the control device 13, the image analysis module 134 accesses the encoder 133 (S1), and reads the latest landscape image from the video stored in the encoder 133 (S2).
And the said image analysis module 134 performs the filtering process which extracts only the analysis area R (refer FIG. 3) of the landscape image read by said step S2 (S3).
Next, the image analysis module 134 reads whether or not the signs 31 to 33 are present in the analysis area R of the landscape image extracted in step S3. That is, here, it is specified whether or not the current position of the vehicle 1 has reached the installation positions of the signs 31 to 33, that is, the base station switching positions P1 to P3.

Specifically, the image analysis module 134 detects the presence or absence of the signs 31 to 33 by matching processing between an image in the analysis area R and a preset star mark. At this time, in the matching process, it is desirable to convert the color space of the landscape image from the RGB system to the HSV system. Thus, matching processing can be performed without changing the threshold values of various parameters in image processing even in a low luminance situation such as evening or night.
For example, when the vehicle 1 is traveling at a speed of 60 km / h and a landscape image is captured at 15 frames / s by the camera 12, the vehicle 1 travels 1 m per frame. Therefore, in order to realize real-time processing, it is necessary to suppress one sequence of the handover processing within 0.1 s. In this regard, in step S4, since the star mark matching process is executed only for the analysis area R, the processing load is significantly reduced compared to the case where the same process is performed for the entire latest image. It is suitable for real-time processing.

If it is determined that the signs 31 to 33 are present in the analysis area R (Yes in S4), the connection destination switching module 135 is notified to that effect, and the process proceeds to step S5. When it is determined that the signs 31 to 33 are not present in the analysis area R (No side of S4), the process returns to step S1 and the same process is repeated for the next latest image.
For example, as shown in FIG. 3A, when the vehicle 1 has not reached the position where the sign 31 is present in the analysis area R, the vehicle 1 has not reached the installation position P1. The determination returns to step S4. On the other hand, as shown in FIG. 3B, when the vehicle 1 further travels and reaches a position where the sign 31 is present in the analysis area R, it is determined that the vehicle 1 has reached the installation position P1. Then, the process proceeds to step S5.

In step S5, the connection destination switching module 135 acquires the identification information of the currently connected base station. For example, the connection destination switching module 135 extracts a MAC address as identification information of the base station from a beacon signal transmitted from the base station. Note that the MAC address is merely an example of identification information for identifying a base station, and may be other information (for example, an IP address) as long as the information can identify the base station.
Next, the connection destination switching module 135 refers to a base station list stored in advance in an internal memory (not shown) and the like, and is viewed from the base station corresponding to the MAC address acquired in step S5. Select the MAC address corresponding to the next base station in the direction of travel. Here, the base station list indicates the order in which the base stations A to C are installed in the traveling direction of the vehicle 1, and is stored in advance in the internal memory of the connection destination switching module 135 or the like. Yes.

In step S7, the connection destination switching module 135 executes processing for switching the communication destination from the base station that is currently established with wireless communication to the base station selected in step S6. Specifically, the connection destination switching module 135 notifies the wireless device 132 of the MAC address of the base station selected in step S6, thereby causing the wireless device 132 to change the wireless communication establishment destination. . As described above, the connection destination switching module 135 when performing switching of the base station that performs wireless communication according to the reading result of the signs 31 to 33 by the image analysis module 134 corresponds to the base station switching means.
As a result, wireless communication is established between the wireless communication terminal Y and the base station selected in step S6. After step S7, the process returns to step S1, and the handover process is repeatedly executed. That is, in the wireless communication terminal Y, the base station of the communication destination is switched in the order of the traveling direction of the vehicle 1 every time the signs 31 to 33 are read.

As described above, in the wireless communication system X according to the embodiment of the present invention, the vehicle 1 has reached the positions P to P3 corresponding to the signs 31 to 33 (Yes in S4). Side), the connected base station is switched to the next base station (S7). Therefore, it is possible to switch to the base station where the wireless communication is to be established next before the electric field strength in the wireless communication with the base station that has established the communication suddenly decreases.
Therefore, in the wireless communication system X, there is no interruption in wireless communication when switching base stations, such as when switching from the base station A to the base station B or when switching from the base station B to the base station C. And a seamless wireless communication environment can be realized. Moreover, unlike the case where the position is specified using a GPS receiver, the current position of the vehicle 1 is specified by reading the signs 31 to 33 installed on the trajectory L along which the vehicle 1 moves. Therefore, the current position of the vehicle 1 can be specified with high accuracy regardless of the surrounding environment (between high-rise buildings, underground, tunnels, etc.) in which the vehicle 1 travels.

Next, a modification of the wireless communication system X will be described. FIG. 5 is a diagram showing another example of the signs 31 to 33, and FIG. 6 is a flowchart for explaining another example of the handover process.
In the radio communication system X described in the present embodiment, as shown in FIGS. 5A to 5C, the star shape common to each of the signs 31 to 33 is displayed on the image drawn on each of the signs 31 to 33. Marks 31a to 33a (an example of a first mark) and numeric images 31b to 33b (an example of a second mark) for identifying each of the signs 31 to 33 are included. In the example shown in FIG. 5, the numeric images 31 b to 33 b are “1” to “3”.
And in the said radio | wireless communications system X, it replaces with the above-mentioned handover process (refer FIG. 4), and the handover process shown in FIG. 6 is performed. Note that the same processing steps as the processing steps shown in FIG. In the handover process shown in FIG. 6, steps S11 to S12 are executed instead of steps S5 to S6 shown in FIG.

When it is detected in step S4 that the star-shaped marks 31a to 33a are present in the analysis area R (Yes side of S4), in the subsequent step S11, the image analysis module 134 performs the above processing in the analysis area R. The numerical images 31b to 33b existing below the star marks 31a to 33a are read. For example, the numbers of the numeric images are read by matching processing for each numeric image of “1” to “3”, OCR processing, or the like.
That is, the image analysis module 134 reads the numerical images 31b to 33b on the condition that the star marks 31a to 33a are read in the step S11.
Thereby, compared with the case where the matching process etc. of the different numerical images 31a-33a for every said label | markers 31-33 are performed in said step S4, the processing burden in this step S4 can be eased. In addition, the present Example 1 is not the meaning which excludes the former structure from this invention, You may read the different numerical images 31a-33c for every said label | markers 31-33 in step S4. It is also possible to use different marks for the marks drawn on the signs 31 to 33, respectively.

In step S12, the base station corresponding to the signs 31 to 33 read in step S11 is selected. Thereby, in the next step S7, the connection destination switching module 135 switches the base station of the communication destination to the base station corresponding to the signs 31 to 33 read in the step S11.
Specifically, correspondence information in which each of the MAC addresses of the base stations A to C is associated with the numeric images 31b to 33b of the signs 31 to 33 is stored in a predetermined storage memory in the image analysis module 134 ( What is necessary is just to memorize | store in an example of a corresponding | compatible information storage means. Then, it is conceivable that the image analysis module 134 is configured to extract the base station corresponding to the numeric images 31b to 33b read in step S11 from the correspondence information. Here, the correspondence information is set as information for specifying the base stations A to C to be connected as communication destinations at the installation positions P1 to P3 of the signs 31 to 33 corresponding to the numeric images 31b to 33b. It is a thing.
As described above, if the base station to which communication is to be connected at the current position of the vehicle 1 is switched based on the numeric images 31b to 33b read in step S11 and the correspondence information, the signs 31 to 33 are temporarily set. Even if one of the above is skipped, the base station corresponding to the sign to be read next can be switched.

The schematic diagram which shows schematic structure of the radio | wireless communications system X which concerns on embodiment of this invention. The block diagram which shows schematic structure of the radio | wireless communication terminal Y which concerns on embodiment of this invention. The figure which shows an example of the landscape image image | photographed with the camera. The flowchart for demonstrating an example of the procedure of the hand-over process performed in the radio | wireless communication terminal Y which concerns on embodiment of this invention. The figure which shows the other example of the labels 31-33. The flowchart for demonstrating the other example of a hand-over process.

Explanation of symbols

A to C: base station L: tracks P1 to P3: installation position R: analysis areas S1, S2,...: Processing procedure (step) number X: wireless communication system Y: wireless communication terminal 1: vehicle (an example of a moving body)
11: Antenna units 11a, 11b: Antenna element 12: Camera 13: Wireless communication control device 131: Switching hub 132: Radio 133: Encoder 134: Image analysis module 135: Connection destination switching module 3: Management units 31-33: Indicator (An example of a landmark)
31a to 33a: Star mark (an example of a first mark)
31b to 33b: number image (an example of a second mark)

Claims (6)

A wireless communication terminal that is mounted on a moving body that moves on a predetermined track and performs wireless communication with any one of a plurality of base stations installed along the track,
Mark reading means for reading a plurality of marks set at a plurality of positions set in advance along the trajectory based on a landscape image photographed by a landscape photographing means for photographing a landscape from the moving body;
Base station switching means for switching the base station for performing wireless communication according to the reading result by the mark reading means;
A wireless communication terminal comprising:   The wireless communication terminal according to claim 1, wherein the mark reading unit reads the presence / absence of the mark in a predetermined region of the landscape image captured by the landscape photographing unit.   3. The wireless communication according to claim 1, wherein the base station switching means switches the plurality of base stations in order of the traveling direction of the mobile body every time the mark reading means reads the mark. Terminal. Correspondence information storage means for storing correspondence information in which the identification information of each of the plurality of landmarks is associated with the identification information of each of the plurality of base stations,
The base station switching means switches to the base station corresponding to the mark based on the identification information of the mark read by the mark reading means and the correspondence information stored in the correspondence information storage means. Item 3. A wireless communication terminal according to any one of Items 1 and 2. Each of the landmarks includes a first landmark common to each of the landmarks and a second landmark for identifying each of the landmarks;
5. The wireless communication terminal according to claim 4, wherein the mark reading means reads the second mark on condition that the first mark is read. A wireless communication terminal mounted on a mobile body moving on a predetermined orbit, and a plurality of base stations installed along the orbit, wherein the wireless communication terminal and the plurality of base stations A wireless communication system for performing wireless communication with any one base station,
A landmark photographing means for photographing a landscape from the moving body, a plurality of landmarks installed at a plurality of positions set in advance along the trajectory, and the landmark based on a landscape image photographed by the landscape photographing means. A wireless communication system, comprising: a mark reading means for reading the base station; and a base station switching means for switching the base station for performing wireless communication according to a reading result by the mark reading means.

Images