JP2003188802A - Wireless communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication method that uses various pieces of information such as positional information and electronic map information usable on a mobile body so as to predict a radio wave communication state, thereby setting a communication method and enhancing the communication efficiency. <P>SOLUTION: A moving path is estimated on the basis of electronic map data and target value information stored in a mobile body. The shield state of a radio wave as a function of time is predicted on the basis of the moving speed and current position of the mobile body, the position of a satellite and building data in an electronic map along the estimated moving path. The predicted shield time and a packet reception (transmission) time are compared according to their relative relation on the basis of the prediction of shield to decide a packet transmission method to be used. The mobile body side transmits the decided packet transmission system to an opposite station (base station) as a communication method control message. Then the mobile body and the opposite station conduct communications according to the communication method designated by the communication method control message. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to communication for mobile objects, and more particularly to a communication method for changing a communication method based on information held by the user.

[0002]

2. Description of the Related Art In the conventional communication method for mobile bodies,
The communication method was changed based only on the past and present reception conditions. For example, TCP (Transmission Control P), which is a communication method widely used on the Internet at present.
In the flow control used in RFC) (RFC 793), a method of determining an optimal congestion window size by judging only from past and present reception conditions is adopted. RFC793 (Request For Comment)
s: Internet Engineering Task Force's summarized Internet-related technology proposals and specifications)
Although it is intended to be applied to general communication methods under a few preconditions, it cannot be said that information is necessarily used effectively in communication for a mobile body holding various electronic information.

[0003]

Generally, in wireless communication intended for a mobile body such as a car, the error rate is generally higher than that for communication intended for a fixed station due to the change in the property of radio wave propagation due to the mobility. Since it is high, there is a problem that the communication efficiency is lowered. In the case of TCP, which is a typical quality assurance communication protocol, every time an error occurs, a quantity of data equivalent to (bandwidth) × (propagation delay time) is wasted. Especially propagation delay
This decrease in efficiency is remarkable in a satellite line with a large (RTT: Round Trip Time), and the communication efficiency (throughput) sharply decreases as the error rate increases. As a measure against this decrease in throughput, the transport layer (transport layer: the fourth layer of the OSI model, a layer that guarantees communication quality)
Although there is a means to insert a gateway (protocol conversion device) with a unique protocol equivalent to TCP at the level, a large-scale mechanism tightly coupled with TCP is required. An object of the present invention is to improve communication efficiency in a mobile environment with a high bit error rate.

[0004]

[Means for Solving the Problems] Currently, on a moving body such as a car, position information using GPS, detailed electronic map by a car navigation system and planned travel route, VI
Various kinds of information such as near real-time traffic congestion information represented by CS can be obtained. In the present invention, various kinds of information that can be acquired on a moving body such as a vehicle are used and reflected in communication parameters.

In the mobile body, the route to be traveled is predicted in advance based on the electronic map data and the target value information held by the mobile body. Even if it is not possible to grasp all the travel routes to the final destination, the route is predicted based on the traveling lane of the vehicle and the direction indicator information only for a short section. In this way, the time course of the radio wave shielding condition is predicted from the current position of the moving body, the moving speed, the satellite position, and the building data of the electronic map by using the expected route to proceed. The packet transmission method to be used is determined by comparing the packet reception (transmission) time with the estimated interception time based on the shielding prediction. On the mobile side, the determined packet transmission method is transmitted to the partner station (base station) as a communication method control message. After that, the mobile unit and the partner station communicate according to the communication method specified by the communication method control message.

In order to solve the above-mentioned problems, the present invention is characterized by comprising means for predicting the transmission / reception status of radio waves and means for switching the communication system according to the transmission / reception status of radio waves. The means for predicting the transmission / reception status of radio waves is to calculate the operation route from the current position and the destination and evaluate the radio wave shielding by the buildings existing near the route using an electronic map. The means for switching the communication method according to the radio wave transmission / reception status is based on the prediction result of the radio wave transmission / reception status, and when deterioration of the radio wave transmission / reception status is predicted, by switching to a communication method corresponding to a low radio wave transmission / reception status in advance, Prevents deterioration of communication efficiency.

[0007]

FIG. 13 shows a block diagram of the system configuration of the present invention. Via the satellite (1280), the mobile side (1110-1200) and the base station side (1210-1)
270) is configured to communicate. First, a path through which normal communication data flows will be shown taking the mobile body side as an example. The data first received by the antenna 1110 passes through the high frequency unit and the modem unit 1120, and is transmitted to the communication system execution device 1130,
The communication system command device 1140 and the communication utilization application 1180 are reached. Next, the operation characteristic of the present invention for changing the communication method by using the prediction of radio wave shielding will be described.
First, the communication system command device 1140 causes the current position information from the current position information acquisition device 1160, the final destination information from the interpersonal interface 1190, and the electronic map information 1150.
Based on the road information and building information from the vehicle and the moving route information from the route calculation / route instruction device 1170, it is predicted how transmission and reception of radio waves will be blocked on the route.

Next, based on this prediction result, the communication system command device 1140 also sends a communication system control message to the base station side, and changes the communication system to the communication system execution device 1130 of the own station side. Instruct. The communication method execution device 1130 performs communication processing in accordance with the number of times of multiple transmissions designated by the communication method command device 1140 and a designation method such as striping processing. Next, the operation on the base station side will be described. A normal communication data flowing path is an antenna 1210, a high frequency unit and a modem unit 1220, a communication system execution device 1230, a communication system command device 1240,
The order of the communication use application 1250 is the same as that of the mobile body side. The difference from the mobile unit side is that the communication system command device 1240 does not determine the communication system in its own station, but determines the communication system based on an instruction from the mobile unit side. When the communication system control message is received from the mobile unit side, it issues a communication system change instruction to the communication system execution device 1230 in its own station. The communication system execution device 1230 executes communication processing according to an instruction from the communication system command device 1240. Reference numerals 1230 to 1250 are connection management units for individual mobile units, and exist for each mobile unit (1
260).

Exception control bypasses 1200 and 1270 are paths for confirming whether or not the communication control message has surely reached the partner station and the communication control method has been switched.
If the communication control message has not arrived, the communication method command device 1140 monitors and confirms the actual communication via the exception control bypass 1200, and then performs processing such as resending of the communication control message.

FIG. 1 shows a conceptual diagram of an embodiment using the present invention. This FIG. 1 illustrates a space that is virtually reproduced on a moving body in order to obtain a radio wave shielding pattern, not in the actual world.

Reference numeral 10 is the current position of the moving body of interest. 20 is road information as data on an electronic map,
Similarly, 30 is a building on the electronic map. Reference numeral 40 denotes a radio wave source (a satellite or the like is assumed in the figure), and 50 denotes a radio wave shielded area calculated from the positional relationship between the radio wave source and a building.
Now, assuming that the mobile body is moving in the lower right direction in FIG. 1 and is going to pass through the route that makes a left turn at the second building, it is possible to transmit and receive radio waves from the radio wave shielded area. , 60, which is indicated by a thin dotted line. Similarly, a radio wave shield section where radio waves cannot be transmitted and received is indicated by a thick dotted line such as 70. Here, the time transition of the communicable state, which is expected in the future, in consideration of the moving speed of the moving body is as shown in 80. Here, in the case where the transmission pattern of the packet is set so as not to be transmitted multiple times as indicated by 90, the packets B, C, E,
F and G will be missing. On the other hand, if the packet transmission pattern is set to three consecutive transmissions such as 100, all packets can be received (or transmitted). As a penalty due to multiple transmissions, there is a decrease in throughput, but RTT (RoundTripT) such as satellite link
ime: Since the penalty for retransmission is greater in a line with a large round trip propagation time until the response comes back, the packet should be sent multiple times considering the transition of the radio wave shielding state as shown here. By doing so, it can be expected that the throughput will be improved as a whole.

A procedure for notifying the partner station of the communication method will be described with reference to FIG. 610 is the current position of the moving body, 67
0 is future position, 620 is satellite, 630 is base station, 640
Is the route that is going to proceed. In the moving body, the route to be moved is predicted in advance based on the electronic map data and the target value information held by the moving body. Even if you can not grasp all the travel routes to the final destination,
If it is limited to a short section, the route is predicted based on the traveling route type, traveling lane, and direction indicator information of the mobile vehicle. When the planned route 640 is known, it is possible to predict the time transition of the radio wave shielding condition from the moving speed of the moving body, the satellite position, and the building data of the electronic map. If the satellite 620 is not a geostationary satellite, the shielding is predicted by calculating the satellite position at each time on the basis of the satellite orbital parameters. It is desirable to create the shielding prediction pattern on the moving body side, because the moving body side has more information for shielding prediction such as its own position, destination, and estimated operation speed. Based on this shielding prediction,
A communication method that can improve communication efficiency is determined by applying the communication method determination method described in the following embodiments. On the mobile side, the determined communication method is transmitted to the partner station (base station) as a communication method control message 650. After that, the mobile body and the partner station communicate according to the communication method specified by the communication method control message (660). By doing so, the complicated TCP layer is unmodified, and a method that can be performed at the data link layer (OSI second layer) or physical layer (OSI first layer) level is used to improve communication efficiency in a mobile environment. It is possible to improve.

Next, referring to FIG. 3, the relationship between the expected cutoff time and the packet transmission method used will be shown. The expected cutoff time is
The comparison is made in relation to the packet reception (transmission) time. First, if the expected cutoff time is significantly shorter than the packet reception (transmission) time (110), striping is applied. Striping is to improve the error recovery rate by writing a bit string to be transmitted in a rectangular shape and reading it in the transposed matrix direction to rearrange the bit strings and disperse burst errors.
A general description of striping is shown in FIG. 150 is an input data string, 160 is a writing direction, 170 is a bit string storage buffer, 180 is a reading order from the buffer,
Reference numeral 190 is the output of the transmission data string.

Next, when the expected cutoff time is about the same as the packet reception (transmission) time (120), the packet having the same content is transmitted a plurality of times. An example of multiple transmissions 210 in FIG.
Shown in. As shown in FIG. 5, even if there is a missing packet, if at least one of the packets transmitted a plurality of times can be received normally, the missing data will not appear.

When the expected cutoff time becomes longer than the packet reception (transmission) time (130), the packet having the same content is transmitted a plurality of times, and the distributed transmission of a plurality of times is applied. Dispersion of multiple transmissions means that transmissions of the same bucket are not continuous in time, but are transmitted at a certain time interval to disperse them in time. If the distance to be dispersed at this time is larger than the expected cutoff time, the packet survival rate is further improved. 220 of FIG. 5 shows an example of multiple transmissions dispersed over time. In the figure, the same packets are not transmitted in time, but are transmitted at a certain time interval 250 (4 packets in this example). On the other hand, the expected blocking time is about 3 packets (240). In this way, by setting the interval at which the same packet is transmitted to be longer than at least the masking time, even when a plurality of packets are continuously lost, at least one of the same content packets can be received without being lost. , As a whole, normal communication can be performed.

When the expected cutoff time is much longer than the packet reception (transmission) time (140), the session itself is controlled. For example, the user is instructed to configure the session so that the communication is terminated before the expected long-term cutoff starts. Specifically, if the user tries to download a large file that is not completed before the long-term cutoff, a message indicating that it will be interrupted will be displayed, and whether to enter the shielded section to give priority to the completion of the download, Alternatively, an operation is performed to ask if the download is to be stopped. An example of session control is shown at 230 in FIG. Sessions that are likely to end before long-term screening 26
0 is permitted, and the session 270 in which no end is expected even after entering the shielding for a long time presents some kind of presentation to the user in advance. As the processing when the expected cutoff time is long, the other station may be caused to transmit at the timing when communication becomes possible. This aiming method of communication time is, so to speak, when the communication time pattern can be accurately predicted in advance, such as when traveling on a highway at a constant speed, various autopilots such as cruise control, and vehicle group travel using ITS. Especially effective.

FIG. 6 shows the relationship between the nature of interruption occurrence and the packet transmission (reception) method. As indicated by 310, when the shielding frequency is extremely low, high throughput can be obtained by performing communication without performing processing such as multiple transmissions and striping.

Next, as indicated by 320, when the shielding frequency is slightly higher than the state where the shielding frequency is extremely low (displayed as low shielding frequency), multiple transmissions and striping are performed, but the number of multiple transmissions and the degree of dispersion of striping are performed. Is set to a small value, and the error correction processing to be combined is made simple and light in processing to prevent excessive overhead.

Further, when the shielding frequency increases (33
0), increase the number of times of multiple transmissions. In this case, the dispersion interval of multiple transmissions and the dispersion degree of striping are adjusted according to the cutoff time, and the correction code having higher error correction capability is switched.

340 is when there is periodic shielding. In this case, the cycle for continuous multiple transmissions,
Dispersion It is set so that neither the dispersion distance when transmitting multiple times nor the distance of the striping dispersion degree is a value close to an integer multiple of the low order of the cutoff period. By this method, it is possible to prevent a burst-like error caused by interference due to a close cycle, and it is possible to perform communication without impairing the effect of the error prevention measure.

FIG. 7 shows an example of preferential reconnection after interruption for a long time. Reference numeral 350 is a shielding pattern expected on the moving path of the user A. 360 is a session of user A. For user A, long-term occlusion, such as 370, is expected, so endeavor to end the session before the occlusion begins. At this time, if you want to communicate even after the shielding is completed, request the priority reconnection after the restoration of the shielding,
It transmits to the partner station side before the shielding starts (380). The request for prioritized reconnection includes at least the shielding recovery estimated time. The partner station side, which has received the request for the preferential reconnection, performs the reconnection process before and after the shielding recovery estimated time (390). Since the channel used by the user A is released during the blocking period of the user A, the session of another user may be processed from the viewpoint of effective use of the band. FIG. 7 shows an example of processing the session of user B while user A is shielded (400). When important communication is performed, the user A connection may be held during the shielding period and may not be opened to other users.

Next, an example of the correction of the shielding prediction value based on the actual measurement information from another moving body will be shown. Prediction of shielding based on information from electronic maps evaluates geometric shielding using only building shape data. However, in reality, the electronic map and the real world occlusion may be different. For example, due to the presence of a signboard on the roof of a building or a window, a new building that was not available when creating a map, or the presence of a gap filler (GF) that relays radio waves to places where it does not reach directly. This is the case when radio waves can be received. In addition, it is also an example where it is difficult to correct the radio wave reflectance and the transmittance of the wall surface of the building by calculation. Further, it is possible to grasp a more detailed congestion situation that cannot be grasped by VICS or the like based on the information from other mobile bodies. Furthermore, it is possible to make corrections depending on local weather conditions, such as a decrease in signal strength due to cumulonimbus clouds. Regarding unexpected shielding due to these factors, it is useful to improve the accuracy of shielding prediction by adding a correction based on an actual measurement value by another moving body that actually moved on the same route.

FIG. 8 shows an example of the occlusion prediction correction based on the information from another moving body. 410 and 420 are two moving bodies that locally move on the same planned route 440. "Locally the same planned route"
This means that the starting point and the target value do not necessarily have to be the same. It is assumed that 410 is a moving body A and 420 is a moving body B, and the moving body B is ahead. 430 is a base station and 450 is a satellite. First moving body B
To 460 provide the base station with shielding information when the vehicle actually travels on the planned route. The provided actual shielding information is provided to the mobile unit A, which is scheduled to travel on the same route, via the base station 430 (470). In the moving body A, the shielding prediction value 490 before correction is converted into the shielding prediction value 500 after correction based on the actual shielding information. For conversion, Mobile B
Consider the difference between the speed pattern actually moved by and the speed pattern actually moved by the moving body A.

The actual shielding information sent from another moving body is a more detailed speed pattern and transmission / reception status on the moving route of the moving body, and is narrower in the information from another vehicle traveling on the same route. It is possible to obtain information on a location where a local change in traveling speed occurs in the range. As a result, for example, when a local traffic jam occurs due to an accident at a place where radio waves are shielded by a certain building, the shielding pattern becomes a longer shielding time. In addition to changes due to changes in the speed of the moving body, changes in the transmission / reception status of radio waves due to changes in the reflectance of buildings, for example, may not be predicted by calculation. That is, there is a portion where so-called non-line-of-sight communication occurs, which enables transmission and reception even when the radio wave source cannot be seen through due to the reflection of the building. Since it is very difficult to obtain the radio wave reflectance of a general building including multiple reflections, it is not possible to use the radio wave transmission / reception status of other vehicles that have traveled on the same route in the past in the past. It is considered to be effective in improving the prediction accuracy of.

The mobile unit A transmits a control message 510 to the base station side in order to communicate by the communication method based on the corrected shielding prediction. On the side of the base station, communication is performed according to the corrected communication method control message sent from the mobile unit A (520). At the base station,
It has a database 480 for accumulating actual shielding information at various places, and provides it to the mobile body as needed. The offer may be sent to each mobile at the same time in a broadcast manner, or may be sent individually to the mobiles traveling the route of interest.
Alternatively, a request for information may be made to the base station side in order to obtain past actual shielding information from the mobile body side. Further, the same correction can be performed by using the shielding information when the own moving body has moved on the same route in the past without using the information from other moving bodies. In this case, although the accuracy may be inferior to the correction by the moving body that has passed immediately before in terms of time, a moving body that moves on the same route on a daily basis is advantageous in terms of route matching.

Next, referring to FIG. 9, an example of lane selection suggestion when there are a plurality of traffic lanes is shown. Reference numeral 710 is a road having a plurality of traffic lanes, 720 is a radio wave shield such as a building, 730
Is a radio wave shield area calculated from the relationship between the radio wave source and the shield using an electronic map and correction information. Mobile 1 now
If there are many radio wave shielded areas on the lane (740) that is about to pass and there is a passable other lane with less shield, the user is suggested to change to another lane with less shield. Suggestions to the user are output as voice and image information via a personal interface 1190, which will be described later, but may be output integrated with the route instruction of the vehicle guidance device. Reference numeral 750 denotes a moving body after changing the lane to a traveling lane with less radio wave shielding. If there is a restriction on the traveling lane before branching or turning to the left or right, it is not necessary to issue a lane change instruction. Further, reference numeral 760 is an example in which the real landscape and the shielding pattern are combined and displayed on the head-up display when the moving body is a vehicle. In this example, the radio wave shielding area is superimposed and displayed as a pattern on the view from the actual vehicle window. With this display, it is possible to more intuitively understand the radio wave shielded area, and it is possible to change lanes more flexibly than when only the traveling lane is instructed. Further, by visually displaying the difference in shielding between the low elevation satellite and the high elevation satellite, this may be a basis for allowing the user to select the satellite to be used. As a result, the driver himself / herself can select and drive the place where the radio wave shielding is small.

Next, referring to FIG. 10, an example of the route search having the non-shielding priority mode will be shown. Reference numeral 910 denotes a moving body movement route instruction system, which corresponds to a car navigation system when the moving body is an automobile. Reference numeral 920 denotes an indication that the current mode is the route calculation mode, 930 a button for instructing to preferentially search for an expressway in the route calculation, and 940 also indicates that a general road is preferentially searched in the route calculation. A priority button 950 for instructing is a button for instructing to preferentially search for a route in which the radio waves scheduled for communication are not shielded in the non-shielding priority button route calculation. By pressing the non-occlusion priority button and calculating the route, it is possible to take a route with less occlusion. At this time, the route may be calculated including the traveling lane. As a search condition, a satellite (a station name or a channel name that indirectly refers to) a communication target, a ground electric field transmission station, or the like may be input.
For satellites whose elevation and azimuth changes with time,
By inputting the departure date and time (or only the time), the shielding information that more accurately reflects the satellite position can be used as the basis for the search.

Next, the correction of the shielding pattern prediction will be described with reference to FIG. The shield pattern is calculated based on the positional relationship between the radio wave transmission source and the radio wave shield on the electronic map.
The change in the position of the mobile body on the electronic map is calculated based on the expected moving speed pattern of the mobile body. Specifically, based on the predicted value of the moving speed pattern, the integrated travel distance on the planned travel route is calculated, the integrated travel distance is converted to the position on the electronic map, and the radio wave shielding is evaluated. At this time, various corrections are simply applied to the shielding pattern obtained from the geometrical conditions in the electronic map data, and efforts are made to bring it closer to the actual value. Further, since the predicted value and the actual value deviate with the passage of time, the shielding expected value is appropriately updated. In addition, even when the moving path deviates from the planned route, the shielding expected value is updated.

Reference numeral 810 in FIG. 11 represents a change in moving speed of the moving body with time. The horizontal axis represents elapsed time and the vertical axis represents moving speed. The speed of movement will be improved by various corrections based on the case where the route of the electronic map is moved based on the average acceleration / deceleration pattern after the movement route is determined. To correct the moving speed, traffic congestion / construction information by VICS, more detailed traffic congestion information obtained by actual running of other vehicles, traffic signal switching timing information, weather / road surface information, driving characteristics information of the driver in the case of a vehicle, etc. , Consider the factors that may affect the operating speed of the moving body. Reference numeral 830 is a predicted value of the moving speed and the integrated moving distance after the correction of the moving body at time t0. After the corrected moving speed is obtained, it is converted into a moving integrated distance such as 820. The vertical axis of 820 is the total moving distance, and the horizontal axis is the elapsed time.

After the cumulative moving distance is obtained, first, as a basic pattern, the basic shielding pattern is calculated from the geometric conditions (shielding and diffraction) of the radio wave shielding object in the electronic map. Next, based on this basic shielding pattern, various corrections are added to improve the accuracy of the shielding pattern. The basis of the correction is the actual shielding pattern from another vehicle moving on the same route at a time not far in time, and weather information. The actual shielding pattern from other vehicles is the presence or absence of fading due to the difference in the radio wave reflectance / transmittance of each building, which cannot be grasped only from the geometrical shape of the electronic map, and the out-of-line reception. In particular, the reflection caused by the building is corrected by using the data obtained from actual running, because the reflection property varies greatly depending on the material and structure of the surface. In addition, although reflections and diffractions caused by signboards installed on the top and side of the building are not shown on the electronic map, they are thought to affect the transmission and reception of radio waves. The meteorological information takes into consideration that when the radio wave transmission source is a satellite, the attenuation rate of radio waves is greatly deteriorated and the C / N ratio is greatly deteriorated due to generation of thunderclouds. The other correction information is already used for the correction of the moving speed and is reflected in the corrected moving speed, and therefore is not directly used for the correction of the shielding pattern.

The actual shielding pattern can be used as data when the next moving body moves at a different speed by reversely correcting the speed of another vehicle and making the data independent of the speed. Moreover, although the data to be used are times that are not far in time, if the positions of the radio wave transmission sources are the same, the data may be separated in time with respect to shielding. Regarding the correction of the moving speed, if the data around the same time on the same day of the week can be used, the accuracy can be further improved. Prediction value 860 of the shielding at time t0 (before correction, calculated from only the geometric shape in the electronic map). 870 is a predicted value (after correction) of occlusion at time t0. It can be seen that the shielding pattern is slightly different as compared with 860 before correction. This is because the out-of-line communication and the attenuation rate due to the weather are taken into consideration. 840 is a predicted value of the moving speed of the moving body and the accumulated moving distance at time t1.

The moving speed and the accumulated moving distance of the moving body deviate from the predicted values with the passage of time. Therefore, the predicted value is reviewed when the time passage or the deviation from the predicted value exceeds a certain value. As a result of the review, if the communication method needs to be changed, the communication method control message is sent. For example, when it is found that the corrected occlusion predicted value 880 is different from the previous predicted value at time t1,
As in 881, the communication method update is transmitted. Further, at time t2, when the planned moving route is changed, the corrected shielding prediction value becomes 890, and when it is determined that the communication method needs to be changed, the communication method is updated as in 891. To send. Whether or not the communication method needs to be changed is the case where there is a difference in the increase / decrease in the number of times of multiple transmissions and the necessity of striping processing, which have been described in the previous embodiment.

FIG. 12 is a flow chart showing the procedure for correcting and updating the shielding prediction pattern. First, at 1010, the necessity of updating the shielding prediction is determined. The cause of the update is a case where there is a large gap between the previously predicted moving speed and the shielding, or when the moving body is in the course change to an unplanned route. If it is just after the start, it will be unconditionally updated. 1020
Then, the moving route of the moving body is determined. The data required for route determination are the starting position and the destination. If the starting position is the current position, GPS data may be used. After the moving route is determined, the moving speed is calculated at 1030. The traveling speed is basically based on the case where the route data of the electronic map is passed through on average or in a deceleration pattern, and various corrections are added to more conform to the actual situation. The correction of the traveling speed includes traffic information and construction information by VICS, actual traveling information obtained from other vehicles, traffic signal switching timing, weather information, road surface state information, and operator-specific characteristics. Meteorological information refers to factors that can affect the maximum speed limit due to heavy rain or snowfall and the movement speed of chain regulations. Road surface state information refers to factors that may affect the moving speed among road surface states such as freezing and unpaved. In the operator-specific characteristics, the degree of acceleration / deceleration, the maximum speed and its stability, and the degree of deceleration when turning right or left are taken into consideration. Next, based on the prediction of the moving speed, the integrated moving distance is calculated at 1040.
When the total travel distance is obtained, the position at the future time can be predicted on the electronic map. Based on the moving body position information at a certain point in the future, the shielding determination is performed in 1050 in a time series. The judgment of occlusion is calculated in two steps. In the first step, the position of the source of the radio wave, the position of the moving body, and the positional relationship of the shields stored in the electronic map are calculated in consideration of geometrical shielding and diffraction. In the second stage, correction is performed by taking into consideration the actual shielding pattern due to the actual running of another vehicle and the weather information represented by rainfall attenuation. Using the finally obtained shielding pattern, 1060
Determine the necessity of changing the communication method. For the determination, the communication control method that matches the calculated shielding pattern is compared with the communication control method that is currently applied. If they are the same, no change is required, and if they are not the same, change is required. . When it is determined that the change is required, the communication method control message is transmitted at 1070.

FIG. 14 is an example of the uplink processing of the actual occlusion data on the mobile body side. Further, FIG. 15 is an example of processing on the base station side when receiving actual occlusion data from a mobile station. On the mobile body side, in the uplink necessity determination of the actual shielding information in 1310, the actual shielding uplink is performed by an uplink transmission trigger for each time interval or each moving distance (1320). The end determination of 1330 is a determination of the end of the actual shielding uplink processing task. On the other hand, on the base station side, packet distribution processing (1
340 to 1380). In this process,
After the packet reception processing 1340, it is determined whether the content of the packet is actual occlusion data (1350). When the content of the packet is the actual occlusion data, the actual occlusion data storage processing 1
Perform 60. In the case of a normal packet which is not the actual shielded data, it is transferred to the normal data reception processing 1380. Next, a process for starting transmission of actual occlusion data (1390 to 143)
0) will be described. First, the actual shielding information transmission process is started when the connection with the mobile body is established or when the mobile body uplinks the position information. In the moving body position information reception processing 1390, the position of the moving body is extracted. Based on the extracted position information, the actual shielding data storage database 142
The corresponding actual occlusion data is retrieved from 0 (140
0). In the process of determining the presence / absence of the corresponding position in 1410, when the presence of the corresponding actual occlusion data is confirmed in the actual occlusion data storage database, the actual occlusion data is transmitted (1
430). These actual shielding data storage database 137
0 and 1420 may be the same database,
It may be managed for each road or each road type. Furthermore, when the actual shielding data is managed for each road, or when there is a sudden electromagnetic shielding, etc., regardless of whether there is a request from the vehicle to the vehicle traveling on the corresponding route from the base station The shielding information may be notified.

In all of the above-mentioned embodiments, all the communication-disabled states due to the reduction of the radio wave reception level are expressed as shielded, but the same can be applied to general communication-disabled states such as fading and interference.

[0036]

As described above, according to the present invention, regarding the wireless communication for a mobile body, the position information of the GPS use obtained on the mobile body, the detailed electronic map information by the car navigation system and the planned operation route, and further the VICS. By predicting the communication status using various types of information such as traffic congestion information that is close to real-time, it is possible to always take the communication method that seems to be optimal, so there is a high error peculiar to mobile wireless communication. The decrease in communication efficiency due to the rate can be improved.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an embodiment according to the present invention.

FIG. 2 is a diagram showing an example of notifying a communication method to a partner station.

FIG. 3 is a diagram showing a relationship between an expected cutoff time and a packet transmission method used.

FIG. 4 is a diagram showing an example of striping.

FIG. 5 is a diagram showing an example of a packet transmission method.

FIG. 6 is a diagram illustrating a property of occurrence of blocking and a packet transmission (reception) method.

FIG. 7 is a diagram showing preferential reconnection after a long interruption.

FIG. 8 is a diagram showing an example of correction of shielding prediction based on information from another moving body.

FIG. 9 is a diagram showing an example of a lane selection suggestion when there are multiple traffic lanes.

FIG. 10 is a diagram showing an example of a route search having a non-shielding priority mode.

FIG. 11 is a diagram showing correction and updating of a shielding prediction pattern.

FIG. 12 is a flow of correction and update of the shielding prediction pattern.

FIG. 13 is a system configuration diagram of an embodiment according to the present invention.

FIG. 14 is a flow of uplink of real occlusion information on the mobile body side.

FIG. 15 is an uplink flow of actual shielding information on the base station side.

[Explanation of symbols]

10 ... Current position of moving body, 20 ... Road, 40 ... Radio wave source (satellite etc.), 50 ... Radio wave shielded area calculated from positional relationship between radio wave source and building, 60 ... Radio wave non-shielded section, 70
... radio wave shielding section, 80 ... expected time transition of radio wave shielding, 610 ... moving body (current position), 620 ... satellite, 63
0 ... Base station, 640 ... Scheduled route, 650 ... Communication method control message, 660 ... Communication according to communication method control message, 670 ... Mobile unit (future position), 1130 ...
Communication system execution device, 1140 ... Communication system command device, 11
50 ... Electronic map information, 1160 ... Current position information acquisition device, 1170 ... Route calculation / route designation device, 1180 ... Communication application, 1190 ... Interpersonal interface, 1200, 1270 ... Exception control bypass, 12
30 ... communication method execution device, 1240 ... communication method command device, 1250 ... communication utilization application, 1260 ...
Connection management unit.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5K014 AA01 AA02 CA06 FA11 GA01                 5K034 AA01 EE03 EE09 HH01 HH02                       HH09 HH11 MM01                 5K067 AA01 AA13 BB03 BB36 DD27                       EE02 EE07 EE10

Claims (12)

[Claims] 1. When performing communication for a mobile object such as a car, reception of radio waves based on at least one of the current position, electronic map information, traffic jam information, and weather information held in the mobile object. Alternatively, a communication method characterized by predicting the transmission status and changing the communication method based on the prediction result. 2. The mobile communication method according to claim 1, wherein
Communication efficiency is determined by deciding the communication method based on the expected reception or transmission status of radio waves, notifying the other station of the decided communication method, and then performing communication according to the decided communication method with itself and the other station. A mobile communication method comprising: 3. The mobile communication method according to any one of claims 1 and 2, wherein when the shielding frequency in a certain future time interval is expected to be higher than the current shielding frequency, a packet holding the same content is transmitted a plurality of times. A communication characterized by increasing the number of times of multiple transmissions, and conversely, reducing the number of times of multiple transmissions when it is expected that the shielding frequency of a certain time section in the future will be lower than the current shielding frequency. 4. The mobile communication method according to any one of claims 1 to 3, wherein when it is expected that the frequency of short-time occlusion occurring in a certain time section in the future will be higher than the current frequency, a burst will occur. Communication characterized by striping processing with the diffusion effect of bit errors to improve the survival rate of packets by error correction. 5. The mobile communication method according to any one of claims 1 to 4, wherein when the occurrence frequency of short-time shielding in a certain time section in the future is expected to be higher than the current occurrence frequency, use Communication that is characterized by switching the error correction method to a method with higher correction capability than the currently used method and improving the survival rate of packets by error correction. 6. The mobile communication method according to any one of claims 1 to 5, wherein the striping diffusion distance is cut off when a periodicity is recognized in the occurrence of short-time shielding that occurs in a certain time section in the future. A communication method characterized by improving the survival rate of packets by error correction by not making the interval close to an integral multiple of the occurrence interval. 7. The mobile communication method according to any one of claims 1 to 6, wherein when the occurrence of short-time occlusion occurring in a certain time section in the future has periodicity, the same content packet is transmitted a plurality of times. A communication method characterized by improving the survival rate of a packet by making an interval longer than a screening cycle or not near an integral multiple of the screening cycle. 8. The mobile communication method according to any one of claims 1 to 7, wherein when a long-time occlusion is expected to occur in a certain time period in the future, the session is ended before the long-time occlusion. A communication method characterized by scheduling as follows. 9. The mobile communication method according to claim 8,
A communication method characterized in that if there is a high probability that there will be no cutoff after the end of the cutoff period, priority reconnection after the cutoff is agreed before a long-term cutoff occurs. 10. The mobile communication method according to any one of claims 1 to 9, wherein a radio wave is received or transmitted based on position information, electronic map information, traffic jam information, and weather information held in the mobile body. In predicting the above, a communication method characterized by performing a more accurate shielding prediction by correcting using the radio wave condition of another moving body that has passed the same route in the past. 11. The mobile communication method according to any one of claims 1 to 10, wherein there are a plurality of parallel traffic passages on the same path along which the mobile body moves, and one of them is expected to have better communication conditions. In this case, the mobile communication method is characterized in that the efficiency of communication is improved by instructing the user to travel in a travel section with good communication conditions. 12. The mobile communication method according to any one of claims 1 to 11, wherein, when obtaining a travel route of a mobile body from a departure position to an arrival position, a small amount of shielding is used as an evaluation criterion for the route selection. A moving body movement route instruction system characterized by having the following condition as at least one of the options.