Mobile communication system and communication device

The present invention relates to a mobile communication system and a communication device included in the mobile communication system, and more particularly to a technique for performing highly reliable communication.

In multi-carrier communication represented by the OFDM (Orthogonal Frequency Division Multiplexing) method, as disclosed in Patent Document 1, the receiving device estimates the propagation path based on the received signal, and the propagation path estimation result is sent to the transmitting device. May give feedback. Based on the feedback propagation path estimation results, the transmitting device schedules the resources used for communication with the receiving device, for example, so that the power loss is smaller. As a result, deterioration of communication quality due to the influence of the multipath propagation path can be suppressed.

<p num="0003"><patcit num="1"><text>Japanese Unexamined Patent Publication No. 2011-172160</text></patcit></p>

<p num="0004"> The effect of multipath depends on the location and frequency. In a mobile communication device used in a mobile body, the position when transmitting the propagation path estimation result and the position when communicating with the resources allocated based on the propagation path estimation result are often different. Therefore, when communicating, the influence of the multipath propagation path is different from when the propagation path estimation result is transmitted, and even if communication is performed with resources determined based on the propagation path estimation result, it is highly reliable. There was a risk that communication could not be performed.</p><p num="0005"> The present invention has been made based on this circumstance, and an object of the present invention is to provide a mobile communication system and a communication device capable of highly reliable communication.</p>

<p num="0006"> The above object is achieved by a combination of the features described in the independent claims, and the sub-claims define further advantageous specific examples of the invention. The reference numerals in parentheses described in the claims indicate, as one embodiment, the correspondence with the specific means described in the embodiments described later, and do not limit the technical scope of the present invention. ..</p><p num="0007"> The invention relating to a mobile communication system for achieving the above object includes antennas for selective resources (313, 1372, 2372, 3273, 3373, 4313B) used in a mobile body and for communicating with selected resources. Mobile communication devices (300, 1300, 2300, 3300, 4300) that perform wireless communication using the antenna for selected resources, and target communication devices (200, 1200, 2200, 3200, 3300, 4200) that are the communication targets of the mobile communication device. ) And a mobile communication system (100, 1000, 2000, 3000, 4000), and the propagation path between the reference antenna and the target communication device, which has the same antenna characteristics as the selection resource antenna, including at least the antenna type. The propagation path characteristic acquisition unit (234, 1231, 2232, 3232, 3332, 4231) that acquires the propagation path characteristic information that is the information related to the characteristics in association with the future communication position, and the propagation acquired by the propagation path characteristic acquisition unit. Resource selection unit (235, 1232) that selects the resource used for communication between the mobile communication device and the target communication device at the communication position based on the road characteristic information before the antenna for the selection resource of the mobile communication device is located at the communication position. , 2233, 3234, 3334, 4234).</p><p num="0008"> The propagation path characteristic acquisition unit acquires the propagation path characteristic information, which is information on the propagation path characteristics between the reference antenna and the target communication device having the same antenna characteristics as the selected resource antenna, in association with the future communication position. .. As a result, the resource selection unit can select the resource used for communication between the mobile communication device and the target communication device at the communication position in advance before the antenna for the selection resource of the mobile communication device is located at the communication position. .. Therefore, since the resource selected by the resource selection unit can be used for communication at the communication position, highly reliable communication can be performed.</p><p num="0009"> Further, the invention relating to the communication device for achieving the above object is an invention having the same configuration as the target communication device provided in the invention relating to the mobile communication system. That is, the invention relating to a communication device is a communication device (200, 1200, 2200, 3200, 3300, which is used in a mobile body and communicates with a mobile communication device provided with an antenna for a selective resource for communicating with a selected resource. 4200), the propagation path characteristic information, which is information on the propagation path characteristics between the reference antenna and the communication device whose antenna characteristics including at least the antenna type are common to the selection resource antenna, is associated with the communication position. Communication between the mobile communication device and the communication device at the communication position based on the propagation path characteristic acquisition unit (234, 1231, 2232, 3232, 3332, 4231) to be acquired and the propagation path characteristic information acquired by the propagation path characteristic acquisition unit. It is provided with a resource selection unit (235, 1232, 2233, 3234, 3334, 4232) for selecting the resource used for the mobile communication device before the selection resource antenna of the mobile communication device is located at the communication position.</p>

<figref num="1">It is a figure explaining the structure of the mobile communication system 1 of 1st Embodiment.</figref><figref num="2">It is a block diagram explaining the structure of the base station 200 of FIG.</figref><figref num="3">It is a figure which illustrates the radio wave propagation map 221.</figref><figref num="4">It is a block diagram which shows the function of the control part 230 of FIG.</figref><figref num="5">It is a block diagram which shows the structure of the vehicle-mounted terminal 300 of FIG.</figref><figref num="6">It is a block diagram which shows the function of the control part 330 of FIG.</figref><figref num="7">It is a block diagram which shows the function which the control part 230 of a base station 200 has in 2nd Embodiment.</figref><figref num="8">It is a block diagram which shows the function which the control part 330 of the vehicle-mounted terminal 300 has in 3rd Embodiment.</figref><figref num="9">It is a figure explaining the structure of the mobile communication system 1000 of 4th Embodiment.</figref><figref num="10">It is a block diagram which shows the structure of the in-vehicle terminal 1300 of FIG.</figref><figref num="11">It is a block diagram which shows the function which the control part 1330 of FIG. 10 has.</figref><figref num="12">It is a block diagram which shows the structure of the base station 1200 of FIG.</figref><figref num="13">It is a figure which shows the communication example of the mobile communication system 1000 of 4th Embodiment.</figref><figref num="14">It is a figure explaining the propagation path characteristic information CC determined by the characteristic information determination unit 1331 of FIG.</figref><figref num="15">It is a block diagram which shows the function which the control part 1230 of a base station 1200 has in 5th Embodiment.</figref><figref num="16">It is a figure explaining the structure of the mobile communication system 2000 of 6th Embodiment.</figref><figref num="17">It is a block diagram which shows the structure of the 2nd vehicle-mounted terminal 2300 of FIG.</figref><figref num="18">It is a block diagram which shows the function which the control part 2330 of FIG. 17 has.</figref><figref num="19">It is a block diagram which shows the structure of the 1st vehicle-mounted terminal 2200 of FIG.</figref><figref num="20">It is a block diagram which shows the function which the control part 2230 of FIG. 19 has.</figref><figref num="21">It is a figure which illustrates the propagation path characteristic information CC determined by the characteristic information determination part 2231 of FIG.</figref><figref num="22">It is a figure explaining the structure of the mobile communication system 3000 of 7th Embodiment.</figref><figref num="23">It is a block diagram which shows the structure of the 1st vehicle-mounted terminal 3200 of FIG.</figref><figref num="24">It is a block diagram which shows the structure of the 2nd vehicle-mounted terminal 3300 of FIG.</figref><figref num="25">It is a block diagram which shows the function which the control part 3230 of FIG. 23 has.</figref><figref num="26">It is a block diagram which shows the function which the control part 3330 of FIG. 24 has.</figref><figref num="27">It is a figure which shows the propagation path characteristic information CC determined by the characteristic information determination part 3231 of FIG.</figref><figref num="28">It is a figure explaining the structure of the mobile communication system 4000 of 8th Embodiment.</figref><figref num="29">It is a block diagram which shows the structure of the in-vehicle terminal 4300 of FIG.</figref><figref num="30">It is a figure which shows the function which the control part 4330 of FIG. 29 has.</figref><figref num="31">It is a figure which shows an example of the allocation of the front antenna 4313A and the rear antenna 4313B assigned by the communication control unit 4332 of FIG. 30.</figref><figref num="32">It is a figure which shows the assignment of the front side antenna 4313A and the rear side antenna 4313B, which is different from FIG. 31.</figref><figref num="33">It is a block diagram which shows the structure of the base station 4200 of FIG.</figref><figref num="34">It is a figure which shows the function which the control part 4230 of FIG. 33 has.</figref><figref num="35">It is a figure exemplifying the relationship between the index used by the resource selection unit 4232 of FIG. 34 for selecting a spatial resource, and the usage pattern of the antenna element 4313.</figref>

&lt;First Embodiment&gt; Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the mobile communication system 100 of the first embodiment includes a base station 200 and an in-vehicle terminal 300. The in-vehicle terminal 300 corresponds to the mobile communication device according to the claim.

The base station 200 corresponds to the target communication device and the communication device according to the claim, is fixed at a predetermined place, and communicates with the in-vehicle terminal 300. The in-vehicle terminal 300 is mounted on the vehicle 4 which is a mobile body. Vehicle 4 here means a car. In the example of FIG. 1, the vehicle 4 is traveling on the road 5. Figure 1 shows vehicle 4 at each of the three points P1, P2, and P3. The vehicle 4 located at these three points indicates that the same vehicle 4 has sequentially moved from the point P1 to the point P2 and the point P3. Therefore, although only one vehicle 4 is shown in FIG. 1, the in-vehicle terminal 300 is mounted on each of the plurality of vehicles 4. Further, a plurality of base stations 200 may also be provided.

[Configuration of base station 200] As shown in FIG. 2, the base station 200 includes a communication unit 210, a storage unit 220, and a control unit 230. The communication unit 210 includes a transmission unit 211, a reception unit 212, and an antenna 213. The transmission unit 211 modulates and amplifies various signals input from the control unit 230, and transmits the signals to the outside via the antenna 213. In the transmission unit 211 of the present embodiment, the access method is OFDMA (frequency-division multiple access), and the modulation method is selected from phase shift keying and quadrature amplitude modulation. The receiving unit 212 demodulates the signal received by the antenna 213 and inputs the demodulated signal to the control unit 230.

The storage unit 220 is writable and stores the radio wave propagation map 221 and the road map database 223. The radio wave propagation map 221 is a database that stores propagation path characteristic information CC at various communication positions. Propagation path characteristic information CC is information representing the propagation path characteristics estimated in OFDM. The propagation path characteristic information CC of the present embodiment means the frequency characteristic of the propagation path, and is the characteristic of the intensity and the phase with respect to the frequency. FIG. 3 illustrates the relationship between the frequency and the SN ratio at various communication positions as the propagation path characteristic information CC. From the radio wave propagation map 221, it is possible to know which frequency has a good SN ratio at various communication positions. The radio wave propagation map 221 is created for each model of the in-vehicle terminal 300.

The reason why the radio wave propagation map 221 is created for each model of the vehicle-mounted terminal 300 is that different models of the vehicle-mounted terminal 300 have different antenna characteristics from the antenna 313 included in the vehicle-mounted terminal 300. In this embodiment, the antenna 313 functions as both the reference antenna and the selection resource antenna according to the claim. Since the radio wave propagation map 221 is created for each model of the in-vehicle terminal 300, the radio wave propagation map 221 is created for each antenna 313 of the in-vehicle terminal 300. In addition, since this antenna 313 functions as a reference antenna, the radio wave propagation map 221 is created for each of a plurality of reference antennas. Further, the model of the in-vehicle terminal 300 corresponds to the antenna determination information.

By creating the radio wave propagation map 221 for each model of the in-vehicle terminal 300, the radio wave propagation map 221 can be created based on the propagation path characteristic information CC acquired by the antennas having the same antenna characteristics. However, even if the antenna characteristics are not the same, the radio wave propagation map 221 is created based on the propagation path characteristic information CC acquired by communication with the base station 200 using the reference antenna having the same antenna characteristics as the antenna for the selected resource. You may. Specifically, the antenna characteristics are determined by the directivity and sensitivity in the installed state, or the characteristics that affect them. For example, the antenna type is an element that determines the antenna characteristics. The antenna type is sometimes referred to as the antenna type. Even if the antennas have the same antenna type, the antenna characteristics are generally different if the installation conditions are different. For example, when antennas of the same type are installed on the roof of a vehicle and when they are installed indoors, the antenna characteristics do not become common because the directivity changes. Further, the attitude of the antenna may be included in the antenna characteristics.

Even if the antenna type and antenna orientation are not the same, if they are similar, the antenna characteristics may be common. The extent to which the antenna characteristics are common can be appropriately set according to the required accuracy.

The radio wave propagation map 221 also includes a reliability index database 222. The reliability index database 222 is a database of reliability indexes for each propagation path characteristic information CC included in the radio wave propagation map 221. The reliability index is an index showing how reliable the corresponding propagation path characteristic information CC is. In the present embodiment, the reliability index is determined based on the reproducibility index indicating how much the propagation path characteristic information CC reproduces.

The reproducibility index is a value indicating the spread of the distribution of the propagation path characteristic information CC acquired multiple times at substantially the same communication position, and the wider the spread of the distribution, the lower the reproducibility of the reproducibility index. Become a value. The degree of difference in position to be substantially the same may be appropriately set according to the required accuracy.

The reliability index is, for example, a value obtained by lowering the reproducibility index to the extent that an error occurs for a resource in which an error has occurred. The road map database 223 is a database representing road maps in a digital format.

The control unit 230 is a computer equipped with a CPU 242, a ROM 250, and a RAM 260. The CPU 242 stores the CPU 242 in a non-transitory tangible storage medium such as the ROM 250 while using the temporary storage function of the RAM 260. Run the program that is being used. As a result, the control unit 230 functions as each unit shown in FIG. Further, when the control unit 230 executes these functions, the method corresponding to the program is executed. It should be noted that a part or all of the functions executed by the control unit 230 may be configured in hardware by one or a plurality of ICs or the like.

[Configuration of control unit 230] As shown in FIG. 4, the control unit 230 includes a map update unit 231, a position prediction information acquisition unit 232, a position prediction unit 233, a propagation path characteristic acquisition unit 234, a resource selection unit 235, a communication control unit 236, and a reliability update unit 237. To be equipped.

First, the map update unit 231 will be described. The base station 200 periodically transmits the reference signal R to the surroundings. The reference signal R is a signal for estimating the propagation path of the claim. Specifically, the reference signal R is a pilot signal whose amplitude and phase are known, or a signal including a pilot signal as a part, and is a signal to which a known signal is assigned to all subchannels. When the vehicle-mounted terminal 300 receives the reference signal R, the vehicle-mounted terminal 300 determines the propagation path characteristic information CC based on the reception state of the received reference signal R.

The in-vehicle terminal 300 asynchronously uploads the determined propagation path characteristic information CC to the base station 200 together with the reception position of the reference signal R and the model of the in-vehicle terminal 300. When the receiving unit 212 of the base station 200 receives the propagation path characteristic information CC or the like, the map updating unit 231 acquires the propagation path characteristic information CC, the receiving position, and the model of the in-vehicle terminal 300 from the receiving unit 212. Then, the radio wave propagation map 221 to be updated is specified based on the acquired model, and the specified radio wave propagation map 221 is updated by using the propagation path characteristic information CC acquired from the receiving unit 212 and the reception position. As an example, the update method is the number of propagation path characteristic information CCs acquired so far by combining the propagation path characteristic information CC in the radio wave propagation map 221 corresponding to the acquired reception position and the acquired propagation path characteristic information CC. There is a method of weighted averaging according to.

Next, the position prediction information acquisition unit 232 will be described. As will be described later, the in-vehicle terminal 300 transmits the position prediction information to the base station 200. The position prediction information includes the position of the antenna 313 at the time when the in-vehicle terminal 300 transmits the position prediction information (hereinafter, the position at the time of upload), the moving speed of the in-vehicle terminal 300 at the time of upload, the ID of the in-vehicle terminal 300, and the in-vehicle. Including the model of terminal 300. By including the uploading position and the moving speed, the position of the antenna 313 after the uploading time can be predicted. Further, the position prediction information may include the traveling direction of the in-vehicle terminal 300. However, the traveling direction can be predicted by the time change of the uploading position. Further, if the direction in which the road extends is used in addition to the time change of the position at the time of uploading, the traveling direction can be predicted more accurately. Therefore, it is not essential that the position prediction information includes the traveling direction. This position prediction information is received by the receiving unit 212 of the base station 200. The position prediction information acquisition unit 232 acquires position prediction information from the reception unit 212.

The position prediction unit 233 sequentially determines the future prediction position of the antenna 313 of the vehicle-mounted terminal 300 based on the position prediction information acquired by the position prediction information acquisition unit 232. Specifically, from the moving speed of the in-vehicle terminal 300 included in the position prediction information and the elapsed time from the time when the position prediction information is received, the in-vehicle terminal 300 moves from the time when the in-vehicle terminal 300 uploads the position prediction information. Calculate the travel distance. The predicted position is the position moved in the moving direction of the in-vehicle terminal 300 from the uploading position by this moving distance. The moving direction of the in-vehicle terminal 300 may be determined based on the moving locus of the in-vehicle terminal 300 determined from the position prediction information sequentially acquired from the same in-vehicle terminal 300. Further, when the position prediction information includes the traveling direction of the vehicle-mounted terminal 300, the traveling direction may be the moving direction of the vehicle-mounted terminal 300.

The propagation path characteristic acquisition unit 234 uses the predicted position predicted by the position prediction unit 233 as a communication position, and acquires the propagation path characteristic information CC at this communication position from the radio wave propagation map 221 in association with this communication position. The position prediction information includes the model of the vehicle-mounted terminal 300, and the radio wave propagation map 221 is also created for each model of the vehicle-mounted terminal 300. Therefore, the radio wave propagation map 221 that acquires the propagation path characteristic information CC is the same radio wave propagation map 221 as the model of the in-vehicle terminal 300 included in the position prediction information. In FIG. 3, as an example, the propagation path characteristic information CC (P2) acquired from the radio wave propagation map 221 when the point P2 is set as the predicted position is shown by superimposing the dotted line on the solid line.

The resource selection unit 235 is used for communication with the in-vehicle terminal 300 at the predicted position (that is, future communication position) predicted by the position prediction unit 233 based on the propagation path characteristic information CC acquired by the propagation path characteristic acquisition unit 234. Select a resource. For example, as shown in FIG. 3, the propagation path characteristic information CC (P2) has a high signal-to-noise ratio between frequencies f1 and f2. Therefore, a subcarrier that uses a frequency between frequencies f1 and f2 is selected as a frequency resource used for communication with the vehicle-mounted terminal 300 in the time slot to which the time when the vehicle-mounted terminal 300 is located at the communication position belongs. As a result, the frequency resource in a certain time slot (that is, the time resource) is selected.

Resources are also selected using the reliability index corresponding to the propagation path characteristic information CC. For frequency resources with a relatively low reliability index, the SN ratio is corrected to a relatively small value due to the low reliability, and the frequency resource is selected.

The above explanation was for the case where the propagation path characteristic information CC is acquired only for one in-vehicle terminal 300, but when the propagation path characteristic information CC for a plurality of in-vehicle terminals 300 is acquired, the resource allocation is optimized. Need to be converted.

The optimization ensures that, for example, the total amount or average of the time and frequency resources for which the radio wave attenuation for one or more vehicle-mounted terminals 300 is below a certain level (that is, the signal-to-noise ratio is above a certain level) is maximized. The method of selecting the frequency resource based on the propagation path characteristics after acquiring the propagation path characteristics may be the same as the method used in the existing system such as the LTE cellular system.

The resource selection unit 235 selects a resource to be used for communication with the vehicle-mounted terminal 300 at a predicted position, that is, a position where the vehicle-mounted terminal 300 has not yet reached. Therefore, the resource is selected before the antenna 313 of the vehicle-mounted terminal 300 is located at the predicted position (that is, the communication position).

The communication control unit 236 sequentially determines the position of the in-vehicle terminal 300 based on the position prediction information, and controls the transmission unit 211 with the resource at that position as the resource selected by the resource selection unit 235 to the in-vehicle terminal 300. To communicate.

In this communication, as described in the transmission unit 211, the modulation method can be selected from phase shift keying and quadrature amplitude modulation. Phase shift keying includes BPSK and QPSK, and quadrature amplitude modulation includes 16QAM, 64QAM, 256QAM and the like. These BPSK, QPSK, 16QAM, 64QAM, and 256QAM have a conflicting relationship between communication speed and reliability, and the higher the communication speed, the lower the reliability. Therefore, the reliability of the selected resource is judged by the SN ratio, and the higher the reliability, the higher the communication speed of the modulation method is selected. In other words, the lower the reliability, the lower the communication speed is selected. Further, the lower the reliability, the higher the redundancy (that is, the smaller the coding rate) may be. In the example of FIG. 1, the base station 200 is transmitting a signal to the in-vehicle terminal 300 with the selected frequency resource when the vehicle 4 is located at the point P2.

The above description of the communication control unit 236 is for downlink, but the communication control unit 236 can also communicate with the in-vehicle terminal 300 with the resources selected by the resource selection unit 235 for the uplink. ..

When the resource selected by the resource selection unit 235 is used in the uplink, the communication control unit 236 sends a signal representing the resource selected by the resource selection unit 235 to the vehicle before the in-vehicle terminal 300 is located at the communication position. All you have to do is send it to the terminal 300.

When the in-vehicle terminal 300 receives the signal transmitted by the base station 200, it determines an error in the signal and uploads error resource information including the resource in which the error occurred and the position of the antenna 313 at that time to the base station 200. To do.

When the reception unit 212 of the base station 200 receives this error resource information, the reliability update unit 237 acquires the error resource information from the reception unit 212. Then, based on the acquired error resource information, among the reliability indexes of the reliability index database 222, the reliability index of the communication position and the frequency resource determined by the error resource information is lowered by a predetermined amount or a predetermined ratio.

[Configuration of in-vehicle terminal 300] As shown in FIG. 5, the in-vehicle terminal 300 includes a communication unit 310, a storage unit 320, and a control unit 330. The communication unit 310 includes a transmission unit 311, a reception unit 312, and an antenna 313. The transmission unit 311 modulates and amplifies various signals input from the control unit 330, and transmits the signals to the outside via the antenna 313. The transmission unit 311 of the present embodiment uses SC-FDMA as the access method and the modulation method selected from phase shift keying and quadrature amplitude modulation. The receiving unit 312 demodulates the signal received by the antenna 313 and inputs the demodulated signal to the control unit 330. As described above, the antenna 313 functions as both the reference antenna of the claim and the antenna for the selection resource. The storage unit 320 is controlled by the control unit 330 and various information can be written to it.

The control unit 330 is a computer provided with a CPU 342, a ROM 350, and a RAM 360, and the CPU 342 executes a program stored in a non-transitional substantive recording medium such as the ROM 350 while using the temporary storage function of the RAM 360. As a result, the control unit 330 functions as each unit shown in FIG. Further, when the control unit 330 executes these functions, the method corresponding to the program is executed. In addition, a part or all of the functions executed by the control unit 330 may be configured in hardware by one or a plurality of ICs or the like.

The speed sensor 41 sequentially detects the moving speed of the in-vehicle terminal 300, and inputs the detected moving speed to the control unit 330. As the speed sensor 41, a vehicle speed sensor that detects the speed of the vehicle 4 can be used.

The position detector 42 includes a GNSS receiver that receives a navigation signal transmitted by a navigation satellite included in the GNSS (Global Navigation Satellite System). The current position is sequentially detected based on the navigation signal received by this GNSS receiver. Then, the detected current position is sequentially input to the control unit 330.

[Configuration of control unit 330] As shown in FIG. 6, the control unit 330 includes a position determination unit 331, a communication control unit 332, an error detection unit 338, and a characteristic information determination unit 339. The position determining unit 331 sequentially determines the current position of the antenna 313 by sequentially acquiring the current position detected by the position detector 42. The current position detected by the position detector 42 is the position where the position detector 42 is arranged, not the current position of the antenna 313. Therefore, the current position detected by the position detector 42 may be corrected based on the difference between the position of the antenna 313 and the position of the position detector 42 to obtain the current position of the antenna 313. However, in this embodiment, the antenna 313 functions as a reference antenna and an antenna for selection resources. Therefore, even if the position of the position detector 42 is set as the position of the reference antenna and the position of the selection resource antenna, the accuracy of determining that the selection resource antenna is located at the position of the reference antenna is not affected. If the position error of the reference antenna and the position error of the selection resource antenna are equivalent, it is not necessary to correct the current position detected by the position detector 42 to obtain the current position of the antenna 313.

The communication control unit 332 includes a reception control unit 333 and a transmission control unit 334. The reception control unit 333 decodes the signal of the resource block assigned to the own terminal among the signals transmitted from the base station 200 and received by the antenna 313. Which resource is allocated to the own terminal is determined by using a method predetermined for each wireless system. For example, in the LTE cellular system, the determination is made from the allocation information accommodated in the control channel area in each radio frame. Since the antenna 313 is used to receive the signal of the resource selected by the resource selection unit 235 of the base station 200, it corresponds to the antenna for the selection resource of the claim.

Before explaining the transmission control unit 334, the error detection unit 338 and the characteristic information determination unit 339 will be described. The error detection unit 338 detects whether or not there is an error in the signal transmitted by using the resource allocated to the own terminal by a known error detection method based on an error correction code or the like.

When the receiving unit 312 receives the reference signal R from the base station 200 and acquires the reference signal R from the receiving unit 312, the characteristic information determining unit 339 receives the propagation path characteristic information CC based on the reception state of the reference signal R. To determine. The method of estimating the propagation path characteristic information CC based on the received reference signal R may be the same as the method widely used in MIMO or the like. The propagation path characteristic information CC is also referred to as a propagation path state or a propagation path estimation result. This propagation path characteristic information CC is represented by, for example, power and phase for each frequency.

The transmission control unit 334 includes a characteristic determination information upload unit 335, a position prediction information upload unit 336, and an error resource upload unit 337. The characteristic determination information upload unit 335 uploads the reception position of the reference signal R, the propagation path characteristic information CC determined by the characteristic information determination unit 339, and the model of the in-vehicle terminal 300 from the transmission unit 311 to the base station 200. To do. The upload timing may be an asynchronous timing that is not restricted by the timing at which the propagation path characteristic information CC is determined. In the example of FIG. 1, when the vehicle 4 is located at the point P1, the in-vehicle terminal 300 uploads the propagation path characteristic information CC.

As described above, the propagation path characteristic information CC uploaded by the characteristic determination information upload unit 335 is used in the map update unit 231 of the control unit 230 included in the base station 200 to update the radio wave propagation map 221. Therefore, the antenna 313 will function as a reference antenna.

The position prediction information upload unit 336 uploads the above-mentioned position prediction information to the base station 200 in sequence. As described above, the position prediction information includes the uploading position, which is the position of the antenna 313 at the time when the vehicle-mounted terminal 300 transmits the position prediction information, the moving speed of the vehicle-mounted terminal 300 at the time of uploading, and the ID of the vehicle-mounted terminal 300. And the model of the in-vehicle terminal 300.

The error resource upload unit 337 uploads error resource information representing the resource used for transmission of the signal detected by the error detection unit 338 to the base station 200. The error resource information is information including the frequency resource in which the error occurred and the position when the error occurred.

The timing of uploading the error resource information may also be asynchronous timing. In the example of FIG. 1, when the vehicle 4 is located at the point P3, the in-vehicle terminal 300 uploads the error resource information about the error detected at the point P2.

[Summary of the first embodiment] In the first embodiment described above, the base station 200 associates the propagation path characteristic information CC when communicating with the base station 200 by the antenna 313 in the past with the predicted position, that is, the future communication position, and performs a radio wave propagation map. The propagation path characteristic acquisition unit 234 acquired from 221 is provided.

By acquiring the propagation path characteristic information CC in association with the future communication position, the resource selection unit 235 uses the resource used for communication between the in-vehicle terminal 300 and the base station 200 at the communication position by the antenna 313 of the in-vehicle terminal 300. It can be selected before it is located in the communication position. As a result, the resource selected by the resource selection unit 235 can be used for communication at the communication position, so that highly reliable communication can be performed.

&lt;Second embodiment&gt; Next, the second embodiment will be described. In the following description of the second embodiment, the elements having the same number as the codes used so far are the same as the elements having the same code in the previous embodiments, unless otherwise specified. Further, when only a part of the configuration is described, the embodiment described above can be applied to the other parts of the configuration.

In the second embodiment, as shown in FIG. 7, the control unit 230 includes a distance determination unit 238, a characteristic change determination unit 239, and a characteristic change compensation unit 240 in addition to the configuration of the first embodiment.

The distance determination unit 238 acquires the moving speed of the vehicle-mounted terminal 300 included in the position prediction information from the reception unit 212 that has received the position prediction information. This movement speed is multiplied by a preset communication time per communication to determine the movement distance during one communication period.

The characteristic change determination unit 239 determines the communication position at the start of communication based on the prediction result of the position prediction unit 233. Further, the communication position at the end of communication is determined by adding the moving distance during one communication period determined by the distance determination unit 238 to the communication position at the start of communication. Then, the propagation path characteristic information CC at the communication position at the start of communication and the propagation path characteristic information CC at the communication position at the end of communication are acquired from the radio wave propagation map 221, respectively.

Next, the ratio of the propagation path characteristic information CC at the communication position at the end of communication to the propagation path characteristic information CC at the communication position at the start of communication is defined as the change of the propagation path characteristic information CC during the communication period.

The characteristic change compensation unit 240 compensates the communication signal for reducing the influence of the change in the propagation path characteristic information CC during the communication period, which is determined by the characteristic change determination unit 239, on the communication. Here, the communication signal means to include a transmission signal and a reception signal. Since the radio wave propagation map 221 is required to perform this compensation, if the side provided with the radio wave propagation map 221 is the transmitting side, the communication signal is the transmission signal, and the receiving side is provided with the radio wave propagation map 221. If so, the communication signal is a received signal.

In this embodiment, the base station 200 includes a radio wave propagation map 221. Therefore, when the base station 200 transmits a signal, the signal transmitted by the base station 200 is compensated, and when the base station 200 receives a radio wave, the signal received by the base station 200 is compensated. Make compensation.

As a compensation method, for example, when it is determined by the characteristic change determination unit 239 that the SN ratio is halved at the end of transmission with respect to the start of transmission, the transmission power of the signal at the end of transmission is started. Send at twice the transmission power of the hour. As for the phase, if the characteristic change determination unit 239 determines that the phase advances by 90 degrees at the end of transmission with respect to the start of transmission, the phase of the signal at the end of transmission is the phase at the start of transmission. It is sent with a delay of 90 degrees. The transmission power and phase between the start of transmission and the end of transmission may be determined by interpolation.

Unlike this example, compensation can also be provided for the uplink, that is, the signal transmitted by the vehicle-mounted terminal 300. When compensating for the uplink signal, the power and phase are compensated before the signal received by the antenna 213 is demodulated.

Further, if the in-vehicle terminal 300 is provided with the radio wave propagation map 221 by downloading the radio wave propagation map 221 from the base station 200, the in-vehicle terminal 300 has the distance determination unit 238, the characteristic change determination unit 239, and the characteristic change compensation. The unit 240 may be provided.

As in the second embodiment, the propagation path characteristic information CC at the start of communication and the propagation path characteristic information CC at the end of communication are compared, and compensation is made so as to reduce the influence of changes in the propagation path characteristic information CC on communication. If you do, the reliability of communication will be improved.

&lt;Third embodiment&gt; In the third embodiment, the vehicle-mounted terminal 300 downloads the radio wave propagation map 221 stored in the storage unit 220 of the base station 200 and stores it in the storage unit 320. In the third embodiment, the storage unit 320 corresponds to the download data storage unit of the claim.

The radio wave propagation map 221 stored in the storage unit 320 may be the entire radio wave propagation map 221 stored in the storage unit 220 of the base station 200, but may be limited to the vicinity of the current position of the in-vehicle terminal 300. ..

As shown in FIG. 8, in the third embodiment, the control unit 330 of the vehicle-mounted terminal 300 includes a difference determination unit 340 in addition to the configuration of the first embodiment.

The difference determination unit 340 corresponds to the propagation path characteristic information CC determined by the characteristic information determination unit 339 and the propagation path characteristic information CC determined by the characteristic information determination unit 339 in the radio wave propagation map 221 stored in the storage unit 320. Determine the propagation path characteristic difference, which is the difference from the part. This propagation path characteristic difference may be determined in units of one propagation path characteristic information CC for each communication position, or one propagation path characteristic information CC for each communication position may be further divided into a plurality of frequency bands. It may be decided by comparison.

The characteristic determination information upload unit 335 in the third embodiment uploads the propagation path characteristic difference determined by the difference determination unit 340 as characteristic determination information. By doing so, the amount of data to be uploaded is reduced, so that it is possible to suppress pressure on the communication band.

&lt;Fourth Embodiment&gt; As shown in FIG. 9, the mobile communication system 1000 of the fourth embodiment includes a base station 1200 corresponding to the target communication device according to the claim and an in-vehicle terminal 1300 corresponding to the mobile communication device according to the claim. A plurality of these base stations 1200 and in-vehicle terminals 1300 may be provided.

[Configuration of in-vehicle terminal 1300] As shown in FIG. 9, the vehicle-mounted terminal 1300 includes a front antenna 1371 and a rear antenna 1372. These antennas 1371 and 1372 are antennas having the same structure, and are arranged on the roof of the vehicle 4 so as to be in a front-rear relationship with each other in the traveling direction of the vehicle 4 and at the same height as each other. The front antenna 1371 functions as a reference antenna and the rear antenna 1372 functions as a selection resource antenna.

As shown in FIG. 10, the in-vehicle terminal 1300 includes a communication unit 1310, a storage unit 1320, and a control unit 1330. The communication unit 1310 includes a transmission unit 1311 and a reception unit 1312, and the transmission unit 1311 and the reception unit 1312 switch between two antennas 1371 and 1372 to perform transmission and reception. The transmitting unit 1311 and the receiving unit 1312 have the same functions as the transmitting unit 311 and the receiving unit 312 of the first embodiment except that they have an antenna switching function.

As shown in FIG. 11, the control unit 1330 includes a characteristic information determination unit 1331 and a reception information transmission unit 1332 as functions. First, the characteristic information determination unit 1331 will be described. Also in the fourth embodiment, the base station 1200 periodically transmits the reference signal R. The reference signal R can be received by either the front antenna 1371 or the rear antenna 1372.

The characteristic information determination unit 1331 acquires the reference signal R received by the front antenna 1371 and the rear antenna 1372 from the reception unit 1312, and obtains the propagation path characteristic information CC in the same manner as the characteristic information determination unit 339 of the first embodiment. decide. Hereinafter, the propagation path characteristic information CC determined from the reference signal R received by the front antenna 1371 is referred to as the front antenna propagation path characteristic information CCA, and the propagation path characteristic information CC determined from the reference signal R received by the rear antenna 1372 is referred to as the rear side. Antenna propagation path characteristic information CCB.

The reception information transmission unit 1332 includes the front antenna propagation path characteristic information CCA determined by the characteristic information determination unit 1331, the rear antenna propagation path characteristic information CC B, and the moving speed of the in-vehicle terminal 1300 when the reference signal R is received. , The distance between the front antenna 1371 and the rear antenna 1372 and the ID of the in-vehicle terminal 300 are transmitted from the transmission unit 1311 to the base station 1200.

[Configuration of base station 1200] The base station 1200 has the same hardware configuration as the base station 200 of the first embodiment, and as shown in FIG. 12, the base station 1200 has the same hardware configuration as that of the base station 200 of the first embodiment. It is equipped with a communication unit 1210, a storage unit 1220, and a control unit 1230. Therefore, the transmitting unit 1211, the receiving unit 1212, and the antenna 1213 included in the communication unit 1210 are the same as the transmitting unit 211, the receiving unit 212, and the antenna 213 included in the communication unit 210 in FIG.

The control unit 1230 has a different function from the control unit 230 in FIG. As shown in FIG. 12, the control unit 1230 includes a propagation path characteristic acquisition unit 1231, a resource selection unit 1232, a timing determination unit 1233, and a communication control unit 1234 as functions.

The propagation path characteristic acquisition unit 1231 acquires the front antenna propagation path characteristic information CCA and the rear antenna propagation path characteristic information CCB received by the reception unit 1212 from the reception unit 1212, which is transmitted by the reception information transmission unit 1332 of the in-vehicle terminal 1300. To do. Further, it is assumed that the in-vehicle terminal 1300 is located at the reception position (that is, the communication position) at the time of acquisition. That is, the front antenna propagation path characteristic information CCA and the rear antenna propagation path characteristic information CCB are associated with the position at the time of reception.

The resource selection unit 1232 sets the position where the front antenna 1371 receives the reference signal R as the communication position, and the resource used for communication at that communication position is based on the front antenna propagation path characteristic information CCA acquired by the propagation path characteristic acquisition unit 1231. To decide.

The resource selection unit 1232 further determines the resource in the post-timing post-period. The rear-side timing post-period is after the rear-side communication timing determined by the timing determination unit 1233 described below, and until the rear-side antenna 1372 is predicted to reach the position of the front-side antenna 1371 in the rear-side communication timing. The period.

The moving speed of the in-vehicle terminal 300 is used to determine the rear communication timing. The timing at which the reference signal R corresponding to the front antenna propagation path characteristic information CCA acquired together with this moving speed is transmitted is defined as the front communication timing. The front communication timing is time t1 in FIGS. 13 and 14, the rear communication timing is time t2 in FIGS. 13 and 14, and an example of the period after the rear timing is time t3 in FIGS. 13 and 14. ..

In the post-rear timing period, it can be expected that the propagation path characteristic information CC will be between the front antenna propagation path characteristic information CCA acquired by the propagation path characteristic acquisition unit 1231 at the front communication timing and the rear communication timing, respectively. Based on this predictable propagation path characteristic information CC, the resources in the post-timing post-period are determined.

In the timing determination unit 1233, the position of the rear antenna 1372 is the position where the front antenna 1371 receives the reference signal R (that is, the above-mentioned communication position) based on the moving speed of the in-vehicle terminal 1300 received by the reception unit 1212. Determine the timing. This timing is the above-mentioned rear communication timing.

The communication control unit 1234 periodically transmits the above-mentioned reference signal R from the transmission unit 211. Further, at the rear side communication timing determined by the timing determination unit 1233, the resource selection unit 1232 communicates with the in-vehicle terminal 1300 with the resource selected as the resource to be used in the rear side communication timing. Communication is specifically transmission, transmitting an arbitrary signal with the selected resource. Also, in addition to this arbitrary signal, the reference signal R is transmitted using all subchannels. This communication control unit 1234 corresponds to the communication control unit on the target device side of the claim.

The communication control unit 1234 further communicates with the in-vehicle terminal 1300 with the resource selected by the resource selection unit 1232 as the resource to be used in the rear timing post-period in the rear timing post-period.

[Communication example of the fourth embodiment] At the time t1 shown in FIG. 13 (A), the base station 1200 transmits the reference signal R (t1), and the in-vehicle terminal 1300 receives the reference signal R (t1). After that time t1, the characteristic information determination unit 1331 of the in-vehicle terminal 1300 acquires the reference signal R (t1) received by the front antenna 1371 and determines the front antenna propagation path characteristic information CCA. Then, the reception information transmission unit 1332 transmits the front side antenna propagation path characteristic information CCA, the moving speed, and the ID of the in-vehicle terminal 300 to the base station 1200 before the time t2. The propagation path characteristic acquisition unit 1231 of the base station 1200 acquires these front antenna propagation path characteristic information CCA and the like from the reception unit 1212.

FIG. 14 (A) illustrates the front antenna propagation path characteristic information CCA acquired by the propagation path characteristic acquisition unit 1231 in the state of FIG. 13 (A). In the front antenna propagation path characteristic information CCA shown in this figure, the horizontal axis represents the frequency and the vertical axis represents the SN ratio. The front antenna propagation path characteristic information CCA shown in FIG. 14 (A) has a different SN ratio depending on the frequency.

Therefore, the resource selection unit 1232 of the base station 1200 selects a frequency channel having a good SN ratio as a resource to be used at the communication position. In FIG. 14A, frequencies f3 to f4, f5 to f6, and f7 to f8 are frequency bands having a good SN ratio, so frequency channels using these frequency bands are selected as resources to be used at the communication position.

Further, the timing determination unit 1233 determines the rear communication timing based on the moving speed of the in-vehicle terminal 1300. The rear communication timing is the timing at which the rear antenna 1372 is located at the communication position of the front antenna 1371. The rear communication timing is the time that can be calculated by dividing the distance between the front antenna 1371 and the rear antenna 1372 by the moving speed of the in-vehicle terminal 1300, and the reference signal R corresponding to the front antenna propagation path characteristic information CCA is transmitted. It is the time added to the time that was set.

At this rear communication timing, the base station 1200 communicates with the in-vehicle terminal 1300. The time t2 shown in FIG. 14 (B) is the rear communication timing. At time t2, the communication control unit 1234 transmits the reference signal R. The characteristic information determination unit 1331 and the reception information transmission unit 1332 of the control unit 1330 of the in-vehicle terminal 1300 determine the front antenna propagation path characteristic information CCA, the rear antenna propagation path characteristic information CCB, etc., and transmit them from the transmission unit 1311 to the base station. Send to 1200.

In FIG. 14B, the front antenna propagation path characteristic information CCA (t1) shown by the dotted line is the front antenna propagation path characteristic information CCA at time t1. The front antenna propagation path characteristic information CCA (t2) shown by the solid line is the front antenna propagation path characteristic information CCA at time t2. The CCB (t2) shown by the other solid line is the rear antenna propagation path characteristic information CCB at time t2.

The rear antenna propagation path characteristic information CCB (t2) shown in FIG. 14 (B) is the propagation path characteristic determined by the rear antenna 1372 receiving the reference signal R at the position where the front antenna 1371 receives the reference signal R. Information CC. Therefore, the rear antenna propagation path characteristic information CCB (t2) is similar to the front antenna propagation path characteristic information CCA (t1). From this, it can be seen that when the base station 1200 and the in-vehicle terminal 1300 communicate with each other using the resources selected by the resource selection unit 1232 at time t2, they can communicate at a good signal-to-noise ratio.

Further, the resource selection unit 1232 determines the resource to be used in the post-timing post-period described above. As described above, the rear-side timing post-period is the period after the rear-side communication timing until the rear-side antenna 1372 is predicted to reach the position of the front-side antenna 1371 at the rear-side communication timing. FIG. 13 (C) illustrates the position of the in-vehicle terminal 1300 in the post-timing post-period.

The position of the rear antenna 1372 in FIG. 13 (C) is between the position of the front antenna 1371 at time t1 shown in FIG. 13 (A) and the position of the front antenna 1371 at time t2 shown in FIG. 13 (B). .. Therefore, as shown in FIG. 14 (C), the predicted values of the rear antenna propagation path characteristic information CCB (t3) at time t3 are the front antenna propagation path characteristic information CCA (t1) at time t1 and the front side at time t2. It can be expected to be between the antenna propagation path characteristic information CCA (t2). The rear antenna propagation path characteristic information CCB (t3) shown in FIG. 13 (C) uses the front antenna propagation path characteristic information CCA (t1) and the front antenna propagation path characteristic information CCA (t2) of the front antenna 1371 at time t1. Front antenna propagation path characteristic information based on the ratio of the distance from the position to the position of the rear antenna 1372 at time t3 and the distance from the position of the rear antenna 1372 at time t3 to the position of the front antenna 1371 at time t2. CCA (t1) and front antenna propagation path characteristic information CCA (t2) can be weighted and averaged. Alternatively, depending on the required accuracy, the front antenna propagation path characteristic information CCA (t1) and the front antenna propagation path characteristic information CCA (t2) are simply averaged instead of the weighted average, and the rear antenna propagation path characteristic information CCB ( You may find t3).

The resource selection unit 1232 determines the resource to be used in the rear timing post period based on the rear antenna propagation path characteristic information CCB obtained in this way in the rear timing post period. In the example of FIG. 14 (C), the predicted value of the rear antenna propagation path characteristic information CCB (t3) is a frequency band in which frequencies f9 to f10, f11 to f12, and f13 to f14 have a good SN ratio. Therefore, a frequency channel that uses these frequency bands is selected as a resource to be used at time t3.

Then, the communication control unit 1234 uses this resource to transmit a signal including the ID of the in-vehicle terminal 1300 at time t3 to communicate with the in-vehicle terminal 1300. As a result, communication can be performed with a good signal-to-noise ratio even at time t3.

&lt;Fifth Embodiment&gt; The mobile communication system of the fifth embodiment has the same hardware configuration as that of the fourth embodiment. The control unit 1330 of the in-vehicle terminal 1300 includes a characteristic information determination unit 1331 and a reception information transmission unit 1332, as in the fourth embodiment.

However, in the fifth embodiment, the reception information transmission unit 1332 transmits the current position when the reference signal R is received to the base station 1200 in addition to the various information transmitted in the fourth embodiment. Therefore, in the fifth embodiment, the reception information transmission unit 1332 has the front antenna propagation path characteristic information CCA and the rear antenna propagation path characteristic information CCB determined from the reference signals R received at the front communication timing and the rear communication timing, respectively. Is transmitted from the transmission unit 1311 to the base station 1200 together with the moving speed of the vehicle-mounted terminal 1300 when the reference signal R is received, the distance between the front antenna 1371 and the rear antenna 1372, and the ID of the vehicle-mounted terminal 300.

As shown in FIG. 15, the base station 1200 includes a reproducibility index database 1224 in the storage unit 1220. Further, the control unit 1230 further includes a reproducibility determination unit 1235 as shown in FIG. Except for the configuration shown in FIG. 15, the configuration is the same as that of the base station 1200 of the fourth embodiment, and FIG. 15 is not shown for the same configuration as the base station 1200 of the fourth embodiment.

The reproducibility index database 1224 is a database in which the reproducibility index determined by the reproducibility determination unit 1235 described below is associated with the points.

The reproducibility determination unit 1235 compares the front antenna propagation path characteristic information CCA with the rear antenna propagation path characteristic information CCB determined from the reference signal R transmitted by the base station 1200 at the rear communication timing, and compares the propagation path characteristics. Determine a reproducibility index that represents the reproducibility of information CC. The reproducibility index is calculated as follows, for example. The absolute value of the difference between the SN ratio represented by the front antenna propagation path characteristic information CCA and the SN ratio represented by the rear antenna propagation path characteristic information CCB is calculated for each frequency, and the larger the integrated value of the absolute value of the difference, the more the reproduction. It is used as a reproducibility index indicating that the property is low. Further, the reproducibility determination unit 1235 associates the determined reproducibility index with the communication position, and updates the reproducibility index database 1224 based on the reproducibility index and the communication position.

Further, in the fifth embodiment, the communication control unit 1234 determines the position at the time of communication in the rear communication timing or the period after the rear timing from the current position and the moving speed of the in-vehicle terminal 1300 acquired at the front communication timing. .. Then, based on the determined position at the time of communication and the reproducibility index database 1224, the parameter setting related to the communication reliability in the rear communication timing or the period after the rear timing is determined, and the in-vehicle terminal 1300 is communicated.

The parameter for reliability is, for example, the code rate. The lower the coding rate, that is, the higher the redundancy, the higher the reliability of communication. Therefore, the higher the reproducibility index is, the lower the coding rate is. Further, as a parameter related to reliability, there is a modulation speed. The higher the modulation speed, the lower the reliability of communication. Therefore, the higher the reproducibility index is, the slower the modulation speed is.

As a result, in the fifth embodiment, the reliability of communication in the rear communication timing or the period after the rear timing is further improved.

&lt;Sixth Embodiment&gt; As shown in FIG. 16, the mobile communication system 2000 according to the sixth embodiment includes a first vehicle-mounted terminal 2200 and a second vehicle-mounted terminal 2300. The first in-vehicle terminal 2200 is mounted on the vehicle 6, and the second in-vehicle terminal 2300 is mounted on the vehicle 4. A plurality of the first vehicle-mounted terminal 2200 and the second vehicle-mounted terminal 2300 may be provided. The vehicle 6 corresponds to the first mobile body of the claim, and the first in-vehicle terminal 2200 mounted on the vehicle 6 corresponds to the target communication device of the claim. The vehicle 4 corresponds to the second mobile body of the claim, and the second in-vehicle terminal 2300 mounted on the vehicle 4 corresponds to the mobile communication device of the claim.

First, the configuration of the second in-vehicle terminal 2300 will be described. As shown in FIG. 17, the hardware configuration of the second vehicle-mounted terminal 2300 is the same as that of the vehicle-mounted terminal 1300 of the fourth embodiment.

Therefore, the communication unit 2310 includes a transmission unit 2311, a reception unit 2312, a front antenna 2371, and a rear antenna 2372. These have the same configuration as the transmission unit 1311, the reception unit 1312, the front antenna 1371, and the rear antenna 1372 included in the communication unit 1310 of FIG. Like the front antenna 1371 and the rear antenna 1372, the front antenna 2371 and the rear antenna 2372 are arranged on the roof of the vehicle 4 so as to be in a front-rear relationship with each other in the traveling direction of the vehicle 4 and at the same height as each other. ing. In this sixth embodiment, the front antenna 2371 is the reference antenna and the rear antenna 2372 is the selection resource antenna.

Further, the storage unit 2320 is the same as the storage unit 1320 of FIG. 10, and the control unit 2330 includes a CPU 2340, a ROM 2350, and a RAM 2360. Signals are input to the control unit 2330 from the speed sensor 41 and the position detector 42.

The function of the control unit 2330 is different from that of the control unit 1330 of FIG. 10, and has the function shown in FIG. That is, the control unit 2330 has functions as a transmission signal generation unit 2331 and a communication control unit 2332.

The transmission signal generation unit 2331 periodically generates the second terminal signal St2 transmitted from the transmission unit 2311. The second terminal signal St2 includes a reference signal R, a signal indicating the moving speed of the second vehicle-mounted terminal 2300, and a signal indicating the distance between the antennas. The moving speed of the second in-vehicle terminal 2300 is the speed obtained from the speed sensor 41. The distance between the antennas is the distance between the front antenna 2371 and the rear antenna 2372. If the first in-vehicle terminal 2200 stores the distance between the antennas in advance, it is not necessary to include the distance between the antennas in the second terminal signal St2.

The communication control unit 2332 controls the transmission unit 2211 to transmit the second terminal signal St2 generated by the transmission signal generation unit 2331 from the front antenna 2371. The time t1 shown in FIG. 16 (A) represents this state. When the first in-vehicle terminal 2200 receives the second terminal signal St2, the first in-vehicle terminal 2200 is a resource determined based on the reference signal R included in the second terminal signal St2, and is the resource determined by the second in-vehicle terminal 2300. 1 Send the terminal signal St1. The communication control unit 2332 controls the reception unit 2312 and receives the first terminal signal St1 by the rear antenna 2372.

Next, the configuration of the first in-vehicle terminal 2200 will be described. As shown in FIG. 19, the hardware configuration of the first vehicle-mounted terminal 2200 is the same as that of the second vehicle-mounted terminal 2300. That is, the first vehicle-mounted terminal 2200 includes a communication unit 2210, a storage unit 2220, and a control unit 2230. These have the same configuration as the communication unit 2310, the storage unit 2320, and the control unit 2330 included in the second vehicle-mounted terminal 2300.

The communication unit 2210 includes a transmission unit 2211, a reception unit 2212, a target device front antenna 2271, and a target device rear antenna 2272. These have the same configurations as the transmission unit 2311, the reception unit 2312, the front antenna 2371, and the rear antenna 2372 included in the communication unit 2310 of the second vehicle-mounted terminal 2300. The target device front antenna 2271 and the target device rear antenna 2272 are arranged on the roof of the vehicle 6 so as to be in a front-rear relationship with each other in the traveling direction of the vehicle 6 and at the same height as each other. Further, the distance between the target device front antenna 2271 and the target device rear antenna 2272 is the same as the distance between the front antenna 2371 and the rear antenna 2372.

Further, the control unit 2230 includes a CPU 2240, a ROM 2250, and a RAM 2260, and signals from the speed sensor 41 and the position detector 42 are input to the control unit 2230.

The control unit 2230 has the functions provided in FIG. That is, the control unit 2230 has functions as a characteristic information determination unit 2231, a propagation path characteristic acquisition unit 2232, a resource selection unit 2233, a timing determination unit 2234, and a communication control unit 2235.

As described above, the second in-vehicle terminal 2300 transmits the second terminal signal St2. When the characteristic information determination unit 2231 can receive the second terminal signal St2 with the antenna 2271 on the front side of the target device, the second in-vehicle terminal 2300 is located at the communication position at the time of reception, that is, at the time of transmission for the second in-vehicle terminal 2300. Suppose.

Further, the characteristic information determination unit 2231 determines the propagation path characteristic information CC based on the reference signal R included in the received second terminal signal St2. Then, the determined propagation path characteristic information CC is stored in the storage unit 2220. In the present embodiment, the propagation path characteristic information CC is stored in the storage unit 2220, but the propagation path characteristic information CC may be stored and designated in another storage unit. FIG. 21 illustrates the propagation path characteristic information CC determined by the characteristic information determination unit 2231.

The propagation path characteristic acquisition unit 2232 acquires the propagation path characteristic information CC from the storage unit 2220. The resource selection unit 2233 selects the resource to be used for communication at the communication position determined by the characteristic information determination unit 2231 based on the propagation path characteristic information CC acquired by the propagation path characteristic acquisition unit 2232. The meaning of the resource and the method of selecting the resource are the same as those of the resource selection unit 235 of the first embodiment. When the frequency resource used for communication is selected based on the propagation path characteristic information CC illustrated in FIG. 21, the frequencies f15 to f16, f17 to f18, and f19 to f20 are frequency bands having a good SN ratio in FIG. Therefore, a frequency channel that uses these frequency bands is selected as a resource to be used at the communication position.

The timing determination unit 2234 predicts the timing at which the rear antenna 2372 included in the second in-vehicle terminal 2300 reaches the position where the front antenna 2371 transmits the second terminal signal St2, that is, the communication position determined by the characteristic information determination unit 2231. .. This timing can be calculated by adding the value obtained by dividing the distance between the antennas between the rear antenna 2372 and the front antenna 2371 by the moving speed to the reception time of the second terminal signal St2.

The communication control unit 2235 is located on the side of the target device front antenna 2271 and the target device rear antenna 2272 that is closer to the target device front antenna 2271 when the second terminal signal St2 is received at the timing determined by the timing determination unit 2234. The first terminal signal St1 is transmitted from the antenna to the second in-vehicle terminal 2300 with the resource selected by the resource selection unit 2233. There are no particular restrictions on the content of the first terminal signal St1. As described above, the second in-vehicle terminal 2300 receives the first terminal signal St1 by the rear antenna 2372.

As a transmission condition for the communication control unit 2235 to transmit a signal at this timing, there is a condition that the moving speed of the second in-vehicle terminal 2300 and the moving speed of the first in-vehicle terminal 2200 are equal. If the moving speed of the second in-vehicle terminal 2300 and the moving speed of the first in-vehicle terminal 2200 are not equal, the communication environment during communication of the second terminal signal St2 and the communication environment during communication of the first terminal signal St1 are similar. Because it does not become. In addition to the condition that the moving speeds are the same, the condition that the traveling directions are the same and the condition that the vehicle is traveling on the same road may be added.

The moving speed of the second in-vehicle terminal 2300 is included in the second terminal signal St2, and the moving speed of the first in-vehicle terminal 2200 is determined from the signal of the speed sensor 41 mounted on the vehicle 6. Of course, the fact that the moving speeds are equal here includes substantially the same, and the degree of speed difference to be equal is appropriately set.

When this transmission condition is not satisfied and the moving speed of either the second in-vehicle terminal 2300 or the first in-vehicle terminal 2200 is a low speed close to 0 or 0, the moving speed is considered to be 0 or a low speed close to 0. The terminal can be handled in the same way as the base station 1200. Therefore, when the transmission condition is not satisfied and the moving speed of either the second in-vehicle terminal 2300 or the first in-vehicle terminal 2200 is 0 or a low speed close to 0, the timing determination unit 2234 and the communication control unit 2235 The same control as the timing determination unit 1233 and the communication control unit 1234 of the fourth embodiment is executed.

The time t2 shown in FIG. 16 (B) indicates the state in which the timing determined by the timing determination unit 2234 has been determined. In FIG. 16B, a signal is transmitted from the antenna 2272 on the rear side of the target device. As can be seen by comparing FIG. 16 (A) and FIG. 16 (B), the position of the front antenna 2371 during communication of the second terminal signal St2 and the position of the rear antenna 2372 during communication of the first terminal signal St1 are equal. .. Further, the position of the target device front antenna 2271 during communication of the second terminal signal St2 and the position of the target device rear antenna 2272 during communication of the first terminal signal St1 are also the same. Therefore, the communication environment during communication of the second terminal signal St2 and the communication environment during communication of the first terminal signal St1 are very similar. Therefore, the first terminal signal St1 is communicated by using the resource selected based on the propagation path characteristic information CC determined from the reference signal R included in the second terminal signal St2 to communicate with the first terminal signal St1. Communication can be performed well.

In FIG. 16B, as an easy-to-understand example, the positions of the two antennas 2271 and 2371 during communication of the second terminal signal St2 and the positions of the two antennas 2272 and 2372 during communication of the first terminal signal St1 are equal. An example is shown.

However, since the signal is generally transmitted in discrete time cycles, the communication control unit 2235 cannot transmit the first terminal signal St1 at the exact timing determined by the timing determination unit 2234. In some cases. The "timing determined by the timing determination unit 2234" in the description of the communication control unit 2235 described above means the timing closest to the timing determined by the timing determination unit 2234 among the timings at which signal transmission is possible.

The timing determined by the timing determination unit 2234 may not match the timing at which signal transmission is possible. Therefore, at the timing when the signal can be transmitted, the target device front antenna 2271 may be closer to the position of the target device front antenna 2271 when the second terminal signal St2 is received than the target device front antenna 2272. .. Therefore, the communication control unit 2235 receives the first terminal signal St1 from the target device front antenna 2271 and the target device rear antenna 2272, whichever is closer to the target device front antenna 2271 when the second terminal signal St2 is received. It is sent from.

In the description of the sixth embodiment so far, for convenience of explanation, the functions of the control unit 2230 of the first vehicle-mounted terminal 2200 and the control unit 2330 of the second vehicle-mounted terminal 2300 are different. However, the respective control units 2230 and 2330 may have both of the functions shown in FIGS. 18 and 20. Then, if the second terminal signal St2 is not received, the function of the control unit 2330 of the second in-vehicle terminal 2300 is executed, and if the second terminal signal St2 is received, the control unit 2230 of the first in-vehicle terminal 2200 is executed. All you have to do is execute the function of.

&lt;7th embodiment&gt; As shown in FIG. 22, the mobile communication system 3000 according to the seventh embodiment includes a first vehicle-mounted terminal 3200 mounted on the vehicle 4 and a second vehicle-mounted terminal 3300 mounted on the vehicle 6. A plurality of the first vehicle-mounted terminal 3200 and the second vehicle-mounted terminal 3300 may be provided.

The first in-vehicle terminal 3200 includes a first antenna 3272, a second antenna 3272, and a third antenna 3273. These antennas 3271, 3272, and 3273 are antennas having the same structure, and are arranged in a front-rear relationship with each other in the traveling direction of the vehicle 6 and at equal intervals at the same height.

The second in-vehicle terminal 3300 also has three antennas, a first antenna 3371, a second antenna 3372, and a third antenna 3373. These antennas 3371, 3372, and 3373 are antennas having the same structure as the antennas 3271, 3272, and 3273, and are arranged so as to be in a front-to-back relationship with each other in the traveling direction of the vehicle 4 and at equal intervals at the same height as each other. ing. The spacing between the antennas 3371, 3372, and 3373 is the same as the spacing between the antennas 3272, 3272, and 3273.

As shown in FIG. 23, the hardware configuration of the first in-vehicle terminal 3200 is the first in-vehicle terminal of the sixth embodiment except that it includes three antennas of the first antenna 3272, the second antenna 3272, and the third antenna 3273. Same as the 2200 hardware configuration.

Further, as shown in FIG. 24, the hardware configuration of the second in-vehicle terminal 3300 is the second of the sixth embodiment except that it includes three antennas of the first antenna 3371, the second antenna 3372, and the third antenna 3373. It has the same hardware configuration as the in-vehicle terminal 2300.

Further, the control unit 3230 of the first vehicle-mounted terminal 3200 and the control unit 3330 of the second vehicle-mounted terminal 3300 have the same functions as each other. As shown in FIG. 25, the control unit 3230 of the first in-vehicle terminal 3200 includes a characteristic information determination unit 3231, a propagation path characteristic acquisition unit 3232, a timing determination unit 3233, a resource selection unit 3234, a transmission signal generation unit 3235, and a communication control unit. Equipped with 3236.

Further, as shown in FIG. 26, the control unit 3330 of the second vehicle-mounted terminal 3300 includes the characteristic information determination unit 3331, the propagation path characteristic acquisition unit 3332, the timing determination unit 3333, the resource selection unit 3334, the transmission signal generation unit 3335, and the communication. It is equipped with a control unit 3336.

In the seventh embodiment, the first vehicle-mounted terminal 3200 functions as the target communication device according to the claim, and the second vehicle-mounted terminal 3300 functions as the mobile communication device according to the claim. On the contrary, the first vehicle-mounted terminal 3200 functions as the mobile communication device according to the claim. The state in which the second in-vehicle terminal 3300 functions as the mobile communication device according to the claim and the second in-vehicle terminal 3300 functions as the target communication device according to the claim occurs alternately. In the former case, the vehicle 6 corresponds to the first moving body and the vehicle 4 corresponds to the second moving body. On the other hand, in the latter case, the vehicle 6 corresponds to the second moving body and the vehicle 4 corresponds to the first moving body.

As described above, since the control unit 3230 of the first in-vehicle terminal 3200 and the control unit 2330 of the second in-vehicle terminal 3300 have the same functions as each other, only the control unit 3230 of the first in-vehicle terminal 3200 will explain the functions in detail. To do.

First, the transmission signal generation unit 3235 will be described. The transmission signal generation unit 3235 generates an estimation signal Sc to be transmitted from the transmission unit 3311. The estimation signal Sc is a signal similar to the second terminal signal St2 of the sixth embodiment, and is a signal indicating the movement speed of the reference signal R and the vehicle-mounted terminal (here, the first vehicle-mounted terminal 3200) that transmits this signal. And a signal indicating the distance between the antennas. The distance between the antennas is the distance between the second antenna 3272 and the third antenna 3273. If the second vehicle-mounted terminal 3300 stores the distance between the antennas in advance, it is not necessary to include the distance between the antennas in the estimation signal Sc. This estimation signal Sc may be transmitted together with various well-known signals (hereinafter, this signal) transmitted and received in vehicle-to-vehicle communication. This signal includes, for example, a signal for notifying neighboring vehicles of the behavior of the vehicle 4, such as acceleration and current position.

The communication control unit 3236 controls the transmission unit 3211 to transmit the estimation signal Sc generated by the transmission signal generation unit 3235 from the second antenna 3272. At this time, the second antenna 3272 functions as a front antenna and a reference antenna. On the other hand, when the second antenna 3372 of the second in-vehicle terminal 3300 transmits the estimation signal Sc, the second antenna 3372 functions as the front antenna and the reference antenna.

In FIG. 22 (A), at time t1, the transmission signal generation unit 3335 and the communication control unit 3326 of the second in-vehicle terminal 3300 perform the same processing as the transmission signal generation unit 3235 and the communication control unit 3236, and the second antenna It shows the state where the estimation signal Sc is being transmitted from 3372. The first vehicle-mounted terminal 3200 receives this estimation signal Sc at the first antenna 3272, the second antenna 3272, and the third antenna 3273. The reference numerals shown in parentheses in FIG. 22 indicate the reference numerals used in FIG. 27 for each antenna.

When the characteristic information determination unit 3231 can receive the estimation signal Sc from the first antenna 3272, the second antenna 3272, and the third antenna 3273, the second in-vehicle terminal at the time of reception, that is, at the time of transmission for the second in-vehicle terminal 3300, Suppose the 3300 is located in the communication position.

Further, the characteristic information determination unit 3231 determines the propagation path characteristic information CC based on the reference signal R included in the estimation signal Sc. Then, the determined propagation path characteristic information CC is stored in the storage unit 3220.

FIG. 27 (A) shows the propagation path characteristic information CC determined by the characteristic information determination unit 3231 based on the estimation signal Sc received at time t1. FIG. 27 (A) shows three propagation path characteristic information CCs. The propagation path characteristic information CCA1-B2 (t1) is the propagation path characteristic information CC determined by receiving the estimation signal Sc transmitted by the second antenna 3372 by the first antenna 3721. The propagation path characteristic information CCB1-B2 (t1) is the propagation path characteristic information CC determined by receiving the estimation signal Sc transmitted by the second antenna 3372 by the second antenna 3272. The propagation path characteristic information CCC1-B2 (t1) is the propagation path characteristic information CC determined by receiving the estimation signal Sc transmitted by the second antenna 3372 by the third antenna 3273.

The propagation path characteristic acquisition unit 3232 acquires three propagation path characteristic information CCs determined by using the signals received by the first antenna 3272, the second antenna 3272, and the third antenna 3273, respectively, from the storage unit 3220.

The timing determination unit 3233 predicts the timing at which the third antenna 3373 included in the second in-vehicle terminal 3300 reaches the position where the second antenna 3372 receives the estimation signal Sc, that is, the communication position determined by the characteristic information determination unit 3231. (That is, it is decided in advance). This timing can be calculated by adding the value obtained by dividing the distance between the antennas between the second antenna 3372 and the third antenna 3373 by the moving speed to the reception time of the estimation signal Sc.

The resource selection unit 3234 selects the resource to be used for communication at the communication position determined by the characteristic information determination unit 3231 based on the three propagation path characteristic information CCs acquired by the propagation path characteristic acquisition unit 3232. The meaning of the resource and the method of selecting the resource are the same as those of the resource selection unit 235 of the first embodiment. When selecting a resource, the resource selection unit 3234 further uses the movement speed included in the estimation signal Sc, the movement speed of the first in-vehicle terminal 3200, and the timing determined by the timing determination unit 3333. .. From the difference between the two moving speeds, the speed difference between the first in-vehicle terminal 3200 and the second in-vehicle terminal 3300 can be calculated. This speed difference is multiplied by the time from the current time to the timing determined by the timing determination unit 3333. As a result, the distance between the first in-vehicle terminal 3200 and the second in-vehicle terminal 3300 at the timing determined by the timing determination unit 3233 with respect to the distance between the first in-vehicle terminal 3200 and the second in-vehicle terminal 3300 during communication of the estimation signal Sc. The amount of change (hereinafter referred to as the change distance) can be calculated.

Therefore, at the timing determined by the timing determination unit 3233, the second antenna 3272 is the first antenna 3271 or the first antenna 3272 when the estimation signal Sc is received by this change distance as compared with the time when the estimation signal Sc is received. It can be expected that it is located at a position moved in the direction of the third antenna 3273.

Using this prediction, the resource selection unit 3234 determines the predicted value of the propagation path characteristic information CC when the second antenna 3272 is used at the timing determined by the timing determination unit 3233. Two propagation path characteristic information CCs are used to determine the expected value of the propagation path estimation information. One is the propagation path characteristic information CCB1-B2 (t1) corresponding to the second antenna 3272. The other is propagation path characteristic information CCA1-B2 (t1) and propagation path characteristic information CCC1-B2. Of (t1), it is the propagation path characteristic information CC corresponding to the antenna on the side closer to the second antenna 3272 at the timing determined by the timing determination unit 3233. Propagation path when the second antenna 3272 is used at the timing determined by the timing determination unit 3233 by extrapolating or interpolating these two propagation path characteristic information CCs at the ratio of the change distance to the distance between the antennas, for example. Determine the expected value of characteristic information CC.

The propagation path characteristic information CC shown by the solid line in FIG. 27 (B) is the predicted value of the propagation path characteristic information CCB1-B2 (t2) at the time t2, which is the timing determined by the timing determination unit 3233. The dotted lines in FIG. 27 (B) are the three propagation path characteristic information CCs in FIG. 27 (A) shown for comparison. The predicted value of the propagation path characteristic information CCB1-B2 (t2) shown in FIG. 27 (B) is that the moving speed of the first in-vehicle terminal 3200 is faster than the moving speed of the second in-vehicle terminal 3300. Therefore, at the timing determined by the timing determination unit 3233, as shown in FIG. 22 (B), the second antenna 3272 travels in the direction of the vehicle 6 more than the first antenna 327 when the estimation signal Sc is received. It is located in front. Therefore, the predicted value of the propagation path characteristic information CCB1-B2 (t2) is determined by extrapolation using the propagation path characteristic information CCB1-B2 (t1) and the propagation path characteristic information CCA1-B2 (t1).

After determining the predicted value of the propagation path characteristic information CCB1-B2 (t2), the predicted value of the propagation path characteristic information CCB1-B2 (t2) is used at the communication position in the same manner as in the sixth embodiment. Select the resource used for communication.

In addition to generating the estimation signal Sc described above, the transmission signal generation unit 3235 also generates the estimation signal Sc when the communication position is determined and the resource to be used at the communication position is selected. In addition, the above-mentioned main signal is also generated.

The communication control unit 3236 transmits the estimation signal Sc and this signal generated by the transmission signal generation unit 3235 from the second antenna 3272 at the timing determined by the timing determination unit 3233. At this time, the second antenna 3272 functions as the antenna behind the target device. Further, the first antenna 327 located in front of the second antenna 3272 corresponds to the antenna on the front side of the target device.

The state at time t2 shown in FIG. 22 (B) indicates this state. Of the estimation signal Sc and this signal, the reference signal R is assigned to all subchannels. Other signals are transmitted with the resource selected by the resource selection unit 3234.

In FIG. 22B, the second vehicle-mounted terminal 3300 receives the estimation signal Sc at the first antenna 3371, the second antenna 3372, and the third antenna 3373. However, at this time, the third antenna 3373 is located at the communication position, and the third antenna 3373 functions as the rear antenna and the antenna for the selected resource according to the claim. The signal received by the third antenna 3373 has high communication reliability.

The characteristic information determination unit 3331, which has the same function as the characteristic information determination unit 3231, determines the propagation path characteristic information CC from the estimation signals Sc received by the first antenna 3371, the second antenna 3372, and the third antenna 3373, respectively. .. Further, the position of the second antenna 3372 at the time of reception is set as the communication position. Figure 27 (C) shows the three propagation path characteristic information CCA2-B1 (t2) and CCB2-B1 determined by the characteristic information determination unit 3331 from the estimation signal Sc received at time t2. (t2) and CCC2-B1 (t2) are shown.

The propagation path characteristic acquisition unit 3332 acquires these three propagation path characteristic information CCA2-B1 (t2), CCB2-B1 (t2), and CCC2-B1 (t2) from the storage unit 3320. The timing determination unit 3333 predicts the timing at which the third antenna 3273 included in the first in-vehicle terminal 3200 reaches the position where the second antenna 3272 receives the estimation signal Sc, that is, the communication position determined by the characteristic information determination unit 3331. .. Let the predicted timing be time t3.

The resource selection unit 3334 selects the resource to be used for communication at the communication position determined by the characteristic information determination unit 3331 based on the three propagation path characteristic information CCs acquired by the propagation path characteristic acquisition unit 3332. For resource selection, the expected value of the propagation path characteristic information CCB2-C1 (t3) shown in FIG. 27 (D) is determined by the same processing as that of the resource selection unit 3234. Also in FIG. 27 (D), the three propagation path characteristic information CCs shown in FIG. 27 (C) are shown by dotted lines for comparison. Based on the predicted value of this propagation path characteristic information CCB2-C1 (t3), the resource to be used at the communication position is selected.

The transmission signal generation unit 3335 generates the estimation signal Sc and this signal. Then, at time t3, the communication control unit 3336 transmits the estimation signal Sc and this signal from the second antenna 3372. FIG. 22 (C) shows this state. Comparing FIGS. 22 (A) and 22 (C), it can be seen that the states are the same except that the positions of vehicles 4 and 6 are different. From this, it can be seen that in the seventh embodiment, bidirectional communication between the two vehicle-mounted terminals of the first vehicle-mounted terminal 3200 and the second vehicle-mounted terminal 3300 can be repeated with high reliability.

&lt;8th embodiment&gt; As shown in FIG. 28, the mobile communication system 4000 of the eighth embodiment includes a base station 4200 corresponding to the target communication device according to the claim and an in-vehicle terminal 4300 corresponding to the mobile communication device according to the claim. A plurality of these base stations 4200 and in-vehicle terminals 4300 may be provided.

[Configuration of in-vehicle terminal 4300] As shown in FIG. 28, the vehicle-mounted terminal 4300 includes a plurality of antenna elements 4313. The plurality of antenna elements 4313 are antennas having the same structure as each other, and are periodically arranged on the roof of the vehicle 4 at the same height and periodically.

These plurality of antenna elements 4313 are dynamically assigned to two antennas, the front antenna 4313A and the rear antenna 4313B, by applying MIMO technology. That is, the front antenna 4313A and the rear antenna 4313B are a group of antenna elements including a plurality of antenna elements 4313. The front antenna 4313A functions as a reference antenna and the rear antenna 4313B functions as a selection resource antenna.

As shown in FIG. 29, the in-vehicle terminal 4300 includes a communication unit 4310, a storage unit 4320, and a control unit 4330. The communication unit 4310 includes a transmission unit 4311 and a reception unit 4312 in addition to the plurality of antenna elements 4313. The transmitting unit 4311 and the receiving unit 4312 transmit and receive using a plurality of antenna elements 4313. Except for using a plurality of antenna elements 4313, the transmitting unit 4311 and the receiving unit 4312 have the same functions as the transmitting unit 1311 and the receiving unit 1312 of the fourth embodiment.

As shown in FIG. 30, the control unit 4330 includes a characteristic information determination unit 4331, a communication control unit 4332, and a reception status signal transmission unit 4333 as functions.

First, the characteristic information determination unit 4331 will be described. Also in the eighth embodiment, the base station 4200 periodically transmits the reference signal R. The in-vehicle terminal 4300 receives the reference signal R at the front antenna 4313A and the rear antenna 4313B. The antenna element 4313 constituting the front antenna 4313A and the rear antenna 4313B at this time may be determined in advance by the control unit 4330 of the in-vehicle terminal 4300. Further, the base station 4200 may determine and notify the in-vehicle terminal 4300 together with the reference signal R or prior to the reference signal R.

The characteristic information determination unit 4331 acquires the reference signal R received by each antenna element 4313 from the reception unit 4312. Then, for all the antenna elements 4313 constituting the front side antenna 4313A and the rear side antenna 4313B, the propagation path characteristic information CC between the base station 4200 and all the antenna elements 4213 used for transmission is determined. The method for determining each propagation path characteristic information CC may be the same as in the previous embodiments.

The communication control unit 4332 determines the antenna element 413 to be used as the front antenna 4313A and the rear antenna 4313B from the plurality of antenna elements 4313, and constitutes the front antenna 4313A and the rear antenna 4313B. The reference signal R is received by the front antenna 4313A and the rear antenna 4313B. The rear antenna 4313B also transmits the reference signal R in order to determine the reproducibility index. If the reproducibility index is not determined, the rear antenna 4313B does not have to receive the reference signal R.

The communication control unit 4332 uses the moving speed of the in-vehicle terminal 4300 and the transmission cycle at which the base station 4200 transmits a signal in order to determine the antenna element 4313 to be assigned to the front antenna 4313A and the rear antenna 4313B. By multiplying the moving speed of the in-vehicle terminal 4300 by the transmission cycle in which the base station 4200 transmits a signal, the distance traveled by the in-vehicle terminal 4300 in one transmission cycle is calculated.

Antenna element 4313 so that the distance (hereinafter, distance between antennas) d between the antenna elements 4313 corresponding to each other in the front antenna 4313A and the rear antenna 4313B is equal to or greater than the distance that the in-vehicle terminal 4300 moves in one transmission cycle. Determine the allocation of.

Further, the antenna elements 4313 to be assigned to the front antenna 4313A and the rear antenna 4313B are selected so that the antenna elements 4313 constituting the front antenna 4313A and the rear antenna 4313B have the same arrangement shape.

This allocation may be determined in advance by the base station 4200 and notified to the in-vehicle terminal 4300. Further, when the in-vehicle terminal 4300 determines this allocation, the transmission cycle in which the base station 4200 transmits a signal is such that the base station 4200 transmits a signal indicating the transmission cycle and the in-vehicle terminal 4300 receives this signal. Then, the in-vehicle terminal 4300 can acquire it. Further, the signals transmitted by the base station 4200 may be sequentially received and measured. FIG. 31 shows an example of the allocation of the front antenna 4313A and the rear antenna 4313B. In addition, FIG. 32 shows another example of the allocation of the front antenna 4313A and the rear antenna 4313B. In both the example of FIG. 31 and the example of FIG. 32, the arrangement shapes of the antenna elements 4313 constituting the front antenna 4313A and the rear antenna 4313B are the same.

Further, in the example of FIG. 31, the distance d between the antennas is d1, and in the example of FIG. 32, the distance d between the antennas is d2. d2 is shorter than d1. In this way, the distance d between the antennas can be changed by changing the assignment of the antenna element 4313.

The reception status signal transmission unit 4333 transmits the reception status signal Sr from the transmission unit 4311 to the base station 4200. The reception status signal Sr is the propagation path characteristic information CC for all combinations of all the antenna elements 4313 and the antenna elements 4213 constituting the front antenna 4313A and the rear antenna 4313B, and the in-vehicle terminal 4300 when the reference signal R is received. It is a signal including the moving speed and the current position of the antenna, the distance d between the antennas, and the ID of the in-vehicle terminal 4300.

FIG. 28A shows a state in which the base station 4200 transmits the reference signal R at time t1 and then the in-vehicle terminal 4300 transmits the reception status signal Sr.

[Configuration of base station 4200] As shown in FIG. 33, the base station 4200 includes a plurality of antenna elements 4213 instead of the antenna 213 of FIG. The hardware configuration other than this is the same as that of the base station 200 of the first embodiment, and the base station 4200 includes a communication unit 4210, a storage unit 4220, and a control unit 4230. The communication unit 4210 includes a transmission unit 4211 and a reception unit 4212, and the control unit 4230 includes a CPU 4240, a ROM 4250, and a RAM 4260.

The storage unit 4220 stores the reproducibility index database 4221 and the road map database 4222. The reproducibility index database 4221 is a database in which the reproducibility index determined by the reproducibility determination unit 4235, which will be described later, is associated with the points.

As shown in FIG. 34, the control unit 4230 includes a propagation path characteristic acquisition unit 4231, a resource selection unit 4232, a timing determination unit 4233, a communication control unit 4234, and a reproducibility determination unit 4235 as functions.

The propagation path characteristic acquisition unit 4231 acquires the propagation path characteristic information CC transmitted by the in-vehicle terminal 4300 and received by the reception unit 4212 from the reception unit 4212. Of the acquired propagation path characteristic information CC, the propagation path characteristic information CC corresponding to the front antenna 4313A is designated as the front antenna propagation path characteristic information CCA, and the propagation path characteristic information CC corresponding to the rear antenna 4313B is designated as the rear antenna propagation path characteristic. Information CCB. Further, it is assumed that the in-vehicle terminal 4300 is located at the reception position (that is, the communication position) at the time of acquisition. That is, the front antenna propagation path characteristic information CCA and the rear antenna propagation path characteristic information CCB are associated with the communication position.

The resource selection unit 4232 sets the position where the front antenna 4371A receives the reference signal R as the communication position, and the resource used for communication at that communication position is based on the front antenna propagation path characteristic information CCA acquired by the propagation path characteristic acquisition unit 4231. To decide. In addition to this front antenna propagation path characteristic information CCA, the resource selection unit 4232 acquires a reproducibility index corresponding to the position at the time of reception from the reproducibility index database 4221, and selects a resource using this reproducibility index as well.

FIG. 35 illustrates the relationship between the index used by the resource selection unit 4232 to select a resource and the usage pattern of the antenna element 4313. The reproducibility index is a reproducibility index corresponding to the position at the time of reception obtained from the reproducibility index database 4221.

The amount of resources whose estimated SN ratio is equal to or higher than the standard is determined from the propagation path characteristic information CC expected at the communication position. The propagation path characteristic information CC expected at the communication position is determined in the same manner as in the fifth embodiment.

The method of determining the amount of resources whose estimated SN ratio is equal to or higher than the reference from the determined propagation path characteristic information CC may be the same as the method performed in known MIMO techniques. For example, based on the propagation path characteristic information, the SN ratio in each resource when beamforming, diversity coding, spatial multiplexing (multi-stream) or a combination thereof is used is estimated using known techniques, and this is above the standard. Determine the amount of resources that will be. However, for the sake of simplicity, FIG. 35 shows only a form that uses only one of beamforming, diversity coding, and spatial multiplexing. The resource in this "resource amount" has the same meaning as the conventional embodiment. However, since MIMO technology is used in this embodiment, the resources determined by the resource selection unit 4232 include spatial resources in which the degree of freedom of determination is generated by MIMO technology, and the determination of spatial resources is based on the usage pattern of the antenna element. It is done by choice.

The maximum speed is further determined by considering the modulation speed available for each resource, that is, the amount of data that can be transmitted per resource. The available modulation rate is determined based on the estimated signal-to-noise ratio, and the method may be the same as that performed in known adaptive modulation techniques. For simplicity, FIG. 35 shows a value obtained as a speed 1 for a resource amount of 3, which corresponds to the case where all resources estimated to have an SN ratio equal to or higher than the standard are used at the same modulation speed.

The resource selection unit 4232 selects the resource for the next communication from the index illustrated in FIG. 35 and the index important for the next communication. For example, when communication reliability is used as an important index, single-stream directivity 2, which is a usage pattern with high reproducibility and a large amount of resources with an estimated SN ratio above the standard, is used, and an antenna that determines spatial resources is used. Select as the form. When the communication speed is used as an important index, the two streams having the highest maximum speed are selected as the antenna usage mode. The method of selecting the frequency and time resources is the same as that of the previous embodiments.

The timing determination unit 4233 is the rear communication timing at which the position of the rear antenna 4313B becomes the position where the front antenna 4313A receives the reference signal R based on the moving speed of the in-vehicle terminal 4300 received by the reception unit 4212. To determine.

The communication control unit 4234 periodically transmits the reference signal R from the transmission unit 4211. Further, at the rear communication timing determined by the timing determination unit 4233, an arbitrary signal is transmitted to the in-vehicle terminal 4300 using the resource selected by the resource selection unit 4232 as the resource to be used in the rear communication timing. In addition to this arbitrary signal, the reference signal R is transmitted using all subchannels as in the fifth embodiment. This communication control unit 4234 corresponds to the communication control unit on the target device side of the claim.

The reproducibility determination unit 4235 compares the front antenna propagation path characteristic information CCA with the rear antenna propagation path characteristic information CCB determined from the reference signal R transmitted by the base station 4200 at the rear communication timing, and compares the propagation path characteristics. Determine a reproducibility index that represents the reproducibility of information CC. The method for determining the reproducibility index may be the same as that for the reproducibility determination unit 1235 of the fifth embodiment. Further, the reproducibility determination unit 4235 associates the determined reproducibility index with the communication position, and updates the reproducibility index database 4221 based on the reproducibility index and the communication position. The updated reproducibility index database 4221 is used when selecting resources, as described above.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the following modifications are also included in the technical scope of the present invention. Various changes can be made within the range that does not deviate.

&lt;Modification example 1&gt; Although FIG. 3 illustrates the relationship between the frequency and the SN ratio as the propagation path characteristic information CC, the relationship between the impulse response and the SN ratio may be used instead of the frequency.

&lt;Transformation example 2&gt; In the eighth embodiment, the reproducibility index database 4221 may not be provided, and the reproducibility index may be determined by comparing the signals sequentially transmitted by the in-vehicle terminal 4300. In this case, the reproducibility index is not an index representing the reproducibility at exactly the same position. However, in the eighth embodiment, the reproducibility index is used to determine the usage pattern, and in this case, the usage pattern is determined even if it is not an index showing the reproducibility at exactly the same position. It will be useful information to do. In addition, it is not essential to use the reproducibility index to determine the usage pattern.

&lt;Modification example 3&gt; In the above-described embodiment, the automobile is shown as the moving body, but other moving bodies may be used. Other moving objects include railroad vehicles, bicycles, and pedestrians. Further, when a pedestrian holds the mobile communication device, the radio wave propagation map 221 may be created for each of a plurality of predetermined holding states. The holding state is, for example, front holding, pocket storage, and the like. In order to detect these holding states, it is conceivable that the mobile communication device is provided with a camera like a smartphone, and the front holding is a state in which the face of a pedestrian can be photographed by this camera. If the relative movement amount of the mobile communication device is sequentially detected by the acceleration sensor with the front holding position as a reference, it is possible to detect which holding state the mobile communication device is in. Further, more simply, the mobile communication device may be provided with a display to instruct the pedestrian of the holding state and to have the pedestrian press the button when the instructed holding state is reached.

&lt;Modification example 4&gt; In the above-described embodiment, the reference signal R is transmitted to determine the propagation path characteristic information CC. However, it is not essential to transmit the reference signal R to determine the propagation path characteristic information CC. The reference signal R is a signal known on the receiving side. However, if the receiving side returns the receiving state to the transmitting side, the transmitting side knows the transmitted signal, so that the transmitting side determines the propagation path characteristic information CC from the returned receiving state and the transmitted signal. Can be done. In this case, the signal for determining the propagation path characteristic information CC may be any signal. Therefore, in this way, there is an advantage that the overhead due to the addition of the reference signal R does not occur.

&lt;Modification example 5&gt; The radio wave propagation map 221 may be stored by a server capable of communicating with the base station 200.

&lt;Modification example 6&gt; In the first embodiment, the model of the in-vehicle terminal 300 is used as the antenna determination information, and the propagation path characteristic acquisition unit 234 includes the radio wave propagation map 221 for acquiring the propagation path characteristic information CC in the position prediction information. It was the same radio wave propagation map 221 as the 300 model. This is because if the models are the same, the antenna characteristics are the same. However, it may be determined whether the antenna characteristics are common depending on the model of the in-vehicle terminal 300. The extent to which the difference in antenna characteristics is included in the common range will be determined based on the required performance.

In the modified example 6, antenna determination information different from the model of the in-vehicle terminal 300 is used. Specifically, in the modified example 6, the antenna determination information is the vehicle model name of the vehicle 4. The model name is sometimes called the vehicle name. If the in-vehicle terminal 300 is installed at the time of shipment from the factory of the vehicle 4, the model of the in-vehicle terminal 300 can be specified once the model name of the vehicle 4 is determined, so that the model name of the vehicle 4 can be used as the antenna determination information. .. Since the vehicle model name of the vehicle 4 classifies the vehicle 4, it corresponds to an example of the vehicle classification.

In the sixth modification, the characteristic determination information upload unit 335 and the position prediction information upload unit 336 included in the in-vehicle terminal 300 upload the vehicle model name of the vehicle 4 instead of the model of the in-vehicle terminal 300. In order to upload the vehicle model name of the vehicle 4, the vehicle model name of the vehicle 4 is stored in advance in the storage unit 320 of the in-vehicle terminal 300.

The radio wave propagation map 221 included in the base station 200 is created by the propagation path characteristic information CC for each vehicle model name of the vehicle 4, and the map update unit 231 updates the radio wave propagation map 221 based on the vehicle model name of the vehicle 4. Identify. Further, the propagation path characteristic acquisition unit 234 sets the radio wave propagation map 221 that acquires the propagation path characteristic information CC as the same radio wave propagation map 221 as the vehicle model name of the vehicle 4 included in the position prediction information.

&lt;Modification 7&gt; In the modified example 7, the vehicle type classification is used as the antenna determination information. The vehicle type classification is a classification of vehicle types based on the similarity of antenna characteristics. When the vehicle model name of the vehicle 4 shown in the modification 6 is used as the antenna determination information, it can be considered that the antenna characteristics are the same if the vehicle model names of the vehicle 4 are the same. Therefore, there is an advantage that the resource can be selected based on the propagation path characteristic information CC having the same antenna characteristics as the antenna for the selected resource. However, it is necessary to have a radio wave propagation map 221 for each model name of vehicle 4.

The vehicle type classification is a classification for enhancing the versatility of the radio wave propagation map 221 rather than the vehicle type name of the vehicle 4, and is classified as one within the range where the antenna characteristics are common. Therefore, the vehicle type classification is a broader concept than the vehicle type name of the vehicle 4 shown in the modified example 6. However, when the vehicles are roughly divided, there are concepts such as automobiles and railroad vehicles. These are classifications based on the social infrastructure equipment on which vehicles travel. However, the vehicle classification here is a narrower concept than automobiles and railroad vehicles. Specifically, in the vehicle classification, for example, passenger cars and buses, which are concepts that further classify automobiles, and the Shinkansen, which is a concept that further classifies railway vehicles, are specific vehicle classifications. This vehicle type classification can also be classified according to the total height of the vehicle. It should be noted that the vehicle type classification also corresponds to an example of vehicle classification because it classifies vehicles.

In the modification 7, the characteristic determination information upload unit 335 and the position prediction information upload unit 336 included in the in-vehicle terminal 300 upload the vehicle type classification instead of the model of the in-vehicle terminal 300. In order to upload the vehicle type classification, the vehicle type classification is stored in advance in the storage unit 320 of the in-vehicle terminal 300.

In the radio wave propagation map 221 included in the base station 200, the propagation path characteristic information CC is created for each vehicle type classification, and the map update unit 231 specifies the radio wave propagation map 221 to be updated based on the vehicle type classification. Further, the propagation path characteristic acquisition unit 234 sets the radio wave propagation map 221 that acquires the propagation path characteristic information CC as the same radio wave propagation map 221 as the vehicle type classification included in the position prediction information.

&lt;Modification example 8&gt; In the modified example 8, the installation height of the antenna is used as the antenna determination information. Propagation path characteristics vary with respect to the three-dimensional position. Therefore, the installation height of the antenna is also an antenna characteristic.

In the modified example 8, the characteristic determination information upload unit 335 and the position prediction information upload unit 336 included in the in-vehicle terminal 300 have the installation height of the antenna 313, that is, the installation of the antenna for selection resources, instead of the model of the in-vehicle terminal 300. Upload antenna determination information including height. The installation height of the antenna 313 is stored in advance in the storage unit 320. The antenna determination information to be uploaded includes the antenna type in addition to the installation height of the antenna for selection resources, and may include the attitude of the antenna.

In the radio wave propagation map 221 included in the base station 200, the propagation path characteristic information CC is created for each reference antenna distinguished based on the antenna determination information. That is, in the radio wave propagation map 221, the propagation path characteristic information CC is created according to the installation height of the reference antenna, and is also created by being distinguished by other antenna determination information such as the antenna type.

The map update unit 231 propagates the radio wave propagation map 221 for the reference antenna having the same antenna characteristics such as the installation height as the antenna 313, and the reception position and propagation of the reference signal R uploaded by the characteristic determination information upload unit 335 together with the antenna determination information. Update based on road characteristic information CC.

Further, the propagation path characteristic acquisition unit 234 is a radio wave propagation map 221 that determines the radio wave propagation map 221 that acquires the propagation path characteristic information CC from the antenna determination information other than the antenna installation height included in the position prediction information. Therefore, the radio wave propagation map 221 that satisfies the installation height condition is used.

The installation height condition is a condition that the difference or ratio between the installation height of the antenna 313 and the installation height of the reference antenna included in the position prediction information is within a certain range. When there are a plurality of reference antennas satisfying this condition, the radio wave propagation map 221 corresponding to the reference antenna having the installation height closest to the installation height of the antenna 313 is used as the radio wave propagation map 221 for acquiring the propagation path characteristic information CC. To do.

In this modification 8, the radio wave propagation map 221 can be shared between different vehicle types as long as the antenna characteristics such as the antenna installation height are common even if the vehicle types are different. For example, a station wagon vehicle with a low overall height and a sedan-type vehicle with a high overall height are different in vehicle type, but the antenna installation height may satisfy the above installation height condition. Further, in this modification 8, the radio wave propagation map 221 having a different antenna installation height can be applied to a vehicle having a vehicle height adjustment function, such as some off-road vehicles, even if the vehicle type is the same. ..

&lt;Modification example 9&gt; In the modified example 9, the holding state of the antenna 313 is used as the antenna determination information. Specifically, the holding state is either the antenna is fixed or not fixed. The non-fixed state is a state in which the mobile communication device is a portable terminal and the portable terminal is not held by a holder fixed to the mobile body. Whether or not it is held by the holder fixed to the moving body is determined based on the acceleration detected by the acceleration sensor provided in the portable terminal. When moving without being held by the holder fixed to the moving body, the time change of the acceleration detected by the acceleration sensor becomes more complicated than when it is held by the holder. Therefore, it is determined whether or not the portable terminal is held by the holder from the time change of the acceleration. Further, when not held by the holder fixed to the moving body, the time change of the position is also complicated as compared with the case where it is held by the holder. Therefore, it may be determined whether or not the portable terminal is held by the holder from the time change of the position.

In the ninth modification, the characteristic determination information upload unit 335 and the position prediction information upload unit 336 of the mobile communication device determine the antenna instead of the format of the in-vehicle terminal 300 for the information indicating whether or not the mobile communication device is fixed. Upload as information. The storage unit 320 of the mobile communication device stores whether the mobile communication device is a fixed type or a mobile type. If the mobile communication device is a fixed type, it is assumed that the mobile communication device is fixed. On the other hand, if the mobile communication device is a portable terminal, it is determined from the acceleration or the time change of the position whether or not the mobile communication device is held by the holder fixed to the moving body.

Further, the fixed type mobile communication device also uploads the fixed part as a holding state. The fixed part is also stored in the storage unit 320. The fixed parts are distinguished based on whether or not there is a difference in antenna characteristics. For example, examples of memory of fixed parts are on the roof, mirrors, windows, trunk grids, and the like.

On the other hand, in the case of a portable mobile communication device, it is determined whether or not the mobile communication device is used in a mobile body having a plurality of seats. If it can be determined that the mobile communication device is used in a mobile body having a plurality of seats, it is also determined on which seat the mobile communication device is present.

Then, information indicating whether or not the dynamic communication device is used in a mobile body having a plurality of seats and on which seat it is present is also uploaded as a holding state. Whether or not the mobile communication device is used in a mobile body having a plurality of seats and on which seat the mobile communication device is located are determined based on an inquiry to a user who has the mobile communication device.

The radio wave propagation map 221 included in the base station 200 is created by distinguishing whether the mobile communication device is a fixed type or a portable type in the propagation path characteristic information CC, and is about a fixed type mobile communication device. Is created for each of the above-mentioned fixed sites. On the other hand, as for the portable mobile communication device, the radio wave propagation map 221 is created to distinguish between the case where it is used in a mobile body having a plurality of seats and the case where it is used in other cases, and it is used in a mobile body having a plurality of seats. The radio wave propagation map 221 in the case where it is provided is created for each existing seat.

The map update unit 231 sets the radio wave propagation map 221 to be updated as the radio wave propagation map 221 having the same antenna determination information holding state. Further, the propagation path characteristic acquisition unit 234 sets the radio wave propagation map 221 that acquires the propagation path characteristic information CC as the radio wave propagation map 221 having the same holding state as the antenna determination information.

&lt;Modification example 10&gt; In the modified example 8, in addition to the installation height of the antenna, the antenna type may be used as the antenna determination information. Further, in the modification 9, the antenna type may be used as the antenna determination information in addition to the holding state.

1: Mobile communication system 4: Vehicle 5: Road 6: Vehicle 41: Speed sensor 42: Position detector 100: Mobile communication system 200: Base station 210: Communication unit 211: Transmission unit 212: Receiver 213: Antenna 220: Storage 221: Radio wave propagation map 222: Reliability index database 223: Road map database 230: Control unit 231: Map update unit 232: Position prediction information acquisition unit 233: Position prediction unit 234: Propagation path characteristic acquisition unit 235: Resource selection unit 236: Communication control unit 237: Reliability update unit 238: Distance determination unit 239: Characteristic change determination unit 240: Characteristic change compensation unit 300: In-vehicle terminal 310: Communication unit 311: Transmission unit 312: Reception unit 313: Antenna 320: Storage unit 330: Control unit 331: Position determination unit 332: Communication control unit 333: Reception control unit 334: Transmission control unit 335: Characteristic determination information upload unit 336: Position prediction information upload unit 337 : Error resource upload unit 338: Error detection unit 339: Characteristic information determination unit 340: Difference determination unit 413: Antenna element