JP2019006338A - Radio communication system for vehicle - Google Patents

Abstract

To inhibit communication quality from deteriorating as a radio wave propagation environment changes under an influence of a passenger etc., in a cabin and also to prevent a wiring harness from having a more complex structure or deteriorating in wiring workability.SOLUTION: An on-floor radio communication network 110 having small radio communication ranges AS1-AS6 is arranged in an on-floor space 21, an underfloor radio communication network 120 having a relatively large radio communication range AL is arranged in an underfloor space 22, and those networks are interconnected by wireless or wired. In the underfloor space 22 etc., a variation of a radio wave propagation environment is small and a stable communication path can be always secured, so an influence of a passenger etc., in a cabin can be avoided. Further, long-distance radio communication is performed under the floor and short-distance radio communication is performed on the floor, so that an optimum communication path can be selected when necessary. If communication quality decreases and a priority of data is high, the communication path under the floor is selected and thus communication quality is secured to shorten transmission delay time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle radio communication system.

  On a vehicle, it is necessary to input signals from various switches and sensors, and to transmit signals for controlling on / off of loads of various electrical components. As such a signal transmission path, a wire harness that is an aggregate of many electric wires is generally used. However, since the number of switches, sensors, loads, and electronic control units (ECUs) that control these switches in a vehicle tends to increase, the structure of the wire harness becomes complicated and the weight increases. There is concern that the search work will be difficult.

  Therefore, it is assumed that wireless communication is adopted for signal transmission on the vehicle. By using wireless communication, it is possible to reduce the number of wired transmission lines, and thus it is possible to simplify the structure of the wire harness to reduce the weight and to facilitate the wiring work.

  For example, Patent Document 1 discloses an operation in which vehicle interior antennas are installed before and after a vehicle interior on a vehicle, and electromagnetic waves are transmitted simultaneously from the plurality of vehicle interior antennas. The control apparatus which performs the operation | movement which transmits is shown. Thereby, the communicable range can be set to an appropriate area.

  Patent Document 2 shows that in a railway vehicle, an antenna for a wireless communication system is attached downward to a frame of an underfloor steel body of the railway vehicle. As a result, wiring work of the antenna cable is facilitated, it is difficult to receive interference from other communication systems, and information transmission efficiency between wireless devices is not reduced.

JP 2002-46541 A JP 2002-137730 A

  For example, when the technique disclosed in Patent Document 1 is employed, antennas are arranged in the front and rear of the passenger compartment, so that the wireless communication range can be widened. However, in the passenger compartment space, the propagation characteristics of radio waves are affected by conductors, passengers, and other structures in the passenger compartment. It is impossible to completely prevent the deterioration of quality.

  Further, in the technique of Patent Document 2, since there is a vehicle structure that is a shield between the radio device of the cab and the antenna under the floor, there is a gap between the radio device of the cab and the antenna under the floor. It is physically connected via an antenna cable. That is, it is assumed that only the space between the under floor of the railway vehicle and the track surface is used as a wireless communication space.

  However, in the case of an automobile, since a large number of electrical components to be controlled are arranged in various locations in the space above the floor surface, if the technique of Patent Document 2 is adopted. The electric cable that penetrates the floor must be placed at various points on the vehicle. As a result, the structure of the wire harness becomes complicated, and the wiring work of the wire harness becomes difficult because it penetrates the floor surface at various locations. In addition, it is necessary to perform measures such as waterproofing and soundproofing for all such penetrating locations.

  Moreover, in the case of a railway vehicle, it is unlikely that problems will occur because there is a sufficient height between the vehicle floor and the track surface. However, in the case of a vehicle such as an automobile, the height between the under-floor surface of the vehicle body and the road surface is often relatively small, and the relative height between the road surface and the floor surface varies with the loading of luggage. . Furthermore, it must be fully considered that various irregularities and obstacles exist on the road surface. Specifically, antennas are installed so as not to reduce the minimum ground clearance stipulated by the Ordinance of the Ministry of Land, Infrastructure, Transport and Tourism, and care is taken so that the antennas do not interfere with road irregularities or obstacles on the road and damage them. There is a need.

  The present invention has been made in view of the above-described circumstances, and the purpose of the present invention is to improve the communication quality by changing the radio wave propagation environment due to the influence of the occupant being a conductor, the carry-on of the occupant, and various structures in the passenger compartment. An object of the present invention is to provide a vehicular wireless communication system capable of suppressing the occurrence of deterioration and preventing the complexity of the structure of the wire harness and the deterioration of the wiring workability.

In order to achieve the above-described object, the vehicle wireless communication system according to the present invention is characterized by the following (1) to (5).
(1) a first wireless communication network including a plurality of wireless communication terminals arranged in a first area on a vehicle;
A second wireless communication network including a plurality of wireless communication terminals, at least one of which is arranged in the second region on the vehicle, in which fluctuations in the wireless communication environment are small compared to the first region When,
With
The first wireless communication network and the second wireless communication network are configured to be able to communicate with each other via a wireless or wired communication path.
A vehicular wireless communication system.

  According to the vehicular radio communication system having the configuration of (1) above, the first radio communication network and the second radio communication network, which are respectively arranged in different regions of the radio communication environment, are mutually connected. Therefore, a plurality of types of wireless communication paths can be used properly according to the situation, and the paths can be optimized so that the communication quality does not deteriorate. In addition, since wireless communication can be used even in a region where the radio wave propagation environment is likely to change due to the influence of passengers, passengers' carry-on objects, and various structures in the passenger compartment, the increase in the number of wired connections can be suppressed. Therefore, the complexity of the structure of the wire harness and the deterioration of the wiring workability can be prevented.

(2) The second region is a space under the floor of the vehicle.
The vehicle radio communication system according to (1) above, wherein

  According to the vehicular radio communication system having the configuration (2) above, the radio wave propagation environment in the second radio communication network does not vary so much, so even if the communication quality in the first radio communication network is degraded, the overall system is high. A communication path capable of maintaining communication quality can be secured at all times.

(3) The plurality of wireless communication terminals in the first wireless communication network perform wireless communication in a range in a predetermined small cell smaller than a space on the vehicle,
The plurality of wireless communication terminals in the second wireless communication network perform wireless communication in a range larger than the small cell and equal to or smaller than the space on the vehicle.
The vehicular wireless communication system according to (1) or (2) above, wherein

  According to the vehicular radio communication system having the configuration (3) above, for example, in a situation where a large number of electrical components are arranged within a narrow range, the communication path of the first radio communication network is used to improve efficiency. Communication is possible. Further, for example, in a situation where the distance between the transmission source and the transmission destination is large, it is possible to reduce the transmission delay time of a signal accompanying communication by using the communication path of the second wireless communication network.

(4) At least one antenna of the plurality of wireless communication terminals in the second wireless communication network is fixed to a lower arm of a wheel suspension.
The vehicle radio communication system according to any one of the above (1) to (3).

  According to the vehicular radio communication system having the configuration (4) described above, fluctuations in the radio communication environment are reduced by fixing the antenna of the radio communication terminal on the lower arm. Moreover, even if the number of passengers on the vehicle increases or the height of the vehicle body fluctuates due to load loading, etc., the height from the road surface to the lower arm is kept constant. It is possible to prevent interference between the obstacle and the antenna.

(5) A communication control unit that performs communication by preferentially selecting one of the communication path of the first wireless communication network and the communication path of the second wireless communication network according to the type of data to be transmitted. Comprising
The vehicular wireless communication system according to (3) above, wherein

  According to the vehicular wireless communication system having the configuration (5) above, for example, with respect to some data that is easily affected by an increase in transmission delay time, an optimal communication path is preferentially set so that the transmission delay time is shortened. It becomes possible to select.

  According to the vehicle wireless communication system of the present invention, it is possible to suppress the deterioration of communication quality due to the fluctuation of the radio wave propagation environment due to the influence of the conductor, the passenger's carry-in, and various structures in the passenger compartment. It becomes possible to prevent the wire harness structure from becoming complicated and the wiring workability from deteriorating. That is, since the first wireless communication network and the second wireless communication network, which are arranged in different regions where the wireless communication environment changes, are mutually connected, a plurality of types of wireless communication paths can be selected depending on the situation. It is possible to properly use the route, and the route can be optimized so that the communication quality does not deteriorate. Further, since wireless communication can be used even in a region where the radio wave propagation environment is likely to fluctuate, an increase in the number of wired connections can be suppressed. Therefore, the complexity of the structure of the wire harness and the deterioration of the wiring workability can be prevented.

  The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through a mode for carrying out the invention described below (hereinafter referred to as “embodiment”) with reference to the accompanying drawings. .

FIG. 1 is a block diagram showing a configuration example of a vehicle radio communication system according to the first embodiment of the present invention. FIG. 2A and FIG. 2B are plan views showing examples of arrangement of components in the above-floor space and under-floor space, respectively, according to the first embodiment of the present invention. FIG. 3 is a perspective view showing a specific installation example of the antenna on the vehicle. FIG. 4 is a flowchart showing a control example of the vehicle radio communication system according to the first embodiment of the present invention. FIG. 5 is a block diagram showing a configuration example of a vehicle radio communication system according to the second embodiment of the present invention. FIG. 6 is a block diagram showing a modification of the second embodiment.

  Specific embodiments relating to the present invention will be described below with reference to the drawings.

<First Embodiment>
<System configuration example>
FIG. 1 shows a configuration example of a vehicle radio communication system 100 according to the first embodiment of the present invention.
The vehicle radio communication system 100 shown in FIG. 1 includes an on-floor radio communication network 110 and an under-floor radio communication network 120. Further, they are connected to each other via connection cables 16 and 17. Although it is possible to connect two networks to each other using wireless communication instead of the connection cables 16 and 17, it is necessary to avoid shielding radio waves by the floor board 20 by some method. When two networks are connected by wireless communication, a wireless communication terminal corresponding to a node at a connection location is equipped with, for example, a plurality of wireless communication units according to the specifications of each network, or transmission of wireless signals Install a function to switch the output.

  The floor wireless communication network 110 is disposed in the floor space 21 above the floor board 20 in the automobile, and the floor wireless communication network 120 is disposed in the floor floor 22 below the floor board 20. The floor board 20 is located at the bottom of a passenger compartment (cabin), which is a passenger's living space in an automobile, and is formed of a steel plate or the like as a conductor.

  The vehicular wireless communication system 100 shown in FIG. 1 is used to transmit necessary signals by data communication between various electrical components in an automobile. That is, for transmitting signals output by various switches and various sensors, transmitting / receiving signals input / output by various electronic control units (ECU), and transmitting signals for controlling on / off of various loads, etc. Used for

  In general, various electrical components to be controlled in the vehicle wireless communication system 100 are present in a distributed state at various locations in the floor space 21 above the floor plate 20. In the vehicular radio communication system 100 shown in FIG. 1, in order to enable transmission of signals of each of these electrical components, a large number of radio communication terminals 10-1 to 10-15 are provided in the vicinity of each electrical component. Are arranged respectively. In the following description, the wireless communication terminals 10-1 to 10-15 may be omitted as the wireless communication terminal 10 when it is not necessary to distinguish them.

  Each of the wireless communication terminals 10-1 to 10-15 uses radio waves in a radio frequency band such as a microwave or a millimeter wave, for example, and is limited to a relatively narrow range having a diameter of about 1 meter. Has a function of performing communication with other wireless communication terminals. Each of the wireless communication terminals 10-1 to 10-15 has an antenna 10a for transmitting and receiving radio waves.

  In the example illustrated in FIG. 1, a plurality of on-floor small cells AS1, AS2, AS3, AS4, AS5, and AS6 are formed in the on-floor space 21. For example, the wireless communication terminals 10-1, 10-2, and 10-3 belong to the floor small cell AS1, and can perform wireless communication with other wireless communication terminals in this cell.

  Similarly, the wireless communication terminals 10-3 to 10-6 belong to the floor small cell AS2, the wireless communication terminals 10-2 and 10-7 to 10-9 belong to the floor small cell AS3, and the wireless communication terminal 10- 6, 10-8, 10-10, 10-11 belong to the floor small cell AS4, and the wireless communication terminals 10-9, 10-12 to 10-14 belong to the floor small cell AS5, and the wireless communication terminal 10- 11, 10-13 and 10-15 belong to the floor small cell AS6.

  The wireless communication terminal 10-3 is a communication node common to two floor small cells AS1 and AS2 adjacent to each other. Similarly, the wireless communication terminal 10-2 is a communication node common to the two floor small cells AS1 and AS3, and the wireless communication terminal 10-6 is a communication node common to the two floor small cells AS2 and AS4. The wireless communication terminal 10-8 is a communication node common to the two floor small cells AS3 and AS4, and the wireless communication terminal 10-9 is a communication node common to the two floor small cells AS3 and AS5. The communication terminal 10-11 is a communication node common to the two floor small cells AS4 and AS6, and the wireless communication terminal 10-13 is a communication node common to the two floor small cells AS5 and AS6. That is, by using the common communication node, communication can be performed between adjacent cells.

  On the other hand, four wireless communication terminals 15-1, 15-2, 15-3, and 15-4 are arranged at positions apart from each other in the underfloor space 22 as components of the underfloor wireless communication network 120. In addition, each radio | wireless communication terminal 15-1 to 15-4 may arrange | position a main body in the floor space 21, and may arrange | position each antenna 15a only in the floor space 22. In the following description, when there is no need to distinguish between the wireless communication terminals 15-1 to 15-4, the wireless communication terminal 15 may be omitted.

  Each of the wireless communication terminals 15-1 to 15-4 is, for example, within a relatively wide range having a diameter of about several meters, that is, within the entire underfloor area (the entire underfloor area of the vehicle body) AL and between other wireless communication terminals under the floor. It has a function to communicate with. Each of the wireless communication terminals 15-1 to 15-4 has an antenna 15a for transmitting and receiving radio waves. The wireless communication terminals 15-1 to 15-4 are assumed to be configured to use radio waves in a radio frequency band different from that of the radio communication terminal 10 or to use radio signals of different communication formats. Radio waves in the same radio frequency band as the wireless communication terminal 10 may be used.

  In the example shown in FIG. 1, since the space above the floor 21 and the space under the floor 22 are partitioned by the conductive floor plate 20, the radio waves transmitted by the wireless communication terminals 10-1 to 10-15 are wirelessly communicated. The radio waves transmitted by each of the wireless communication terminals 15-1 to 15-4 do not reach the wireless communication terminals 10-1 to 10-15. Therefore, even if the same radio frequency band is used, radio waves do not interfere with each other between the floor wireless communication network 110 and the floor wireless communication network 120.

<Specific arrangement example>
FIG. 2A shows an arrangement example of each component in the above-floor space 21 according to the first embodiment of the present invention, and FIG. 2B shows an arrangement example of each component in the under-floor space 22. FIG. 2A and FIG. 2B show the arrangement state in a plane when the above-floor space 21 and under-floor space 22 of the automobile are viewed from above, respectively. FIG. 3 shows a specific installation example of the antenna on the vehicle of the automobile.

  As shown in FIG. 2A, in the floor space 21 of the vehicle body 30, a plurality of floor small cells AS1 to AS6 are formed at positions adjacent to each other by radio waves transmitted from the antenna 10a of each wireless communication terminal 10. Is done.

  Therefore, it is possible to transmit a signal input / output by an electrical component present at any position in the vehicle interior using the floor wireless communication network 110. Further, when each wireless communication terminal 10 communicates with a remote terminal that is far away, a communication path can be secured by relaying using another terminal in the network. However, in an actual automobile, the radio wave propagation environment may fluctuate greatly because it is affected by each passenger whose electric wave is a conductor, luggage carried by each passenger, and various structures in the passenger compartment. It is assumed that a situation where wireless communication cannot be performed or a situation where the communication quality is remarkably lowered occurs.

  On the other hand, in this embodiment, as shown in FIG. 3, the antenna 15a of each wireless communication terminal 15 is installed on the lower arm 33 of the suspension that supports the four wheels 31 of the automobile. Therefore, as shown in FIG. 2B, the four antennas 15a of the underfloor wireless communication network 120 are arranged in a state of being distributed in the front, rear, left and right of the underfloor space 22.

  Further, each of the wireless communication terminals 15-1 to 15-4 has a slightly larger transmission output than the wireless communication terminal 10 so that the radio wave reaches a partner with a large distance. Therefore, in the underfloor wireless communication network 120, each of the four wireless communication terminals 15-1 to 15-4 is connected to the other wireless communication terminals 15 with respect to a wide underfloor entire area AL that extends almost entirely under the floor of the vehicle body 30. Wireless communication without relay.

  In the case of the underfloor space 22, unlike the overfloor space 21, there are few conductors that affect radio wave propagation on the communication path, and the fluctuation of the radio wave propagation environment is very small. Therefore, in the underfloor wireless communication network 120, good wireless communication quality can always be ensured. In particular, when the antenna 15 a is installed on the lower arm 33 of each wheel 31, the height from the road surface becomes substantially constant regardless of the vertical movement of the vehicle body 30, so that a sufficient minimum ground clearance can be ensured. Therefore, the possibility that the antenna 15a physically interferes with road surface irregularities and obstacles on the road surface is reduced, and damage can be prevented. In addition, since the distance from the floor plate 20 to the antenna 15a can be sufficiently increased, a favorable radio wave propagation environment can be obtained.

  In the present embodiment, the antenna 15a is disposed on the lower arm 33, but may be disposed at another location. For example, it is conceivable to install the antenna 15a near the lower end of the shock absorber 32, a brake drum, or the like. For example, when wiring a wire harness under the floor, it is also conceivable to install the antenna 15a on an exterior member of the wire harness.

  Further, the position where the underfloor wireless communication network 120 is arranged is not necessarily limited to the underfloor space 22. For example, the entire outside of the vehicle structure such as the ceiling space of the passenger compartment is assumed as the arrangement candidate region. That is, the fluctuation of the radio wave propagation environment is small, a good radio wave propagation path can always be ensured, and a place with a large area can be used as a place for installing the antenna 15a.

  In any case, in the case of the underfloor wireless communication network 120, a better radio wave propagation environment can always be secured as compared with the underfloor wireless communication network 110. Moreover, since the communication range of the wireless communication terminals 15-1 to 15-4 is larger than the floor small cells AS1 to AS6, wireless communication with a communication partner at a distance can be performed without relay.

<Characteristic control example of the system>
A control example of the vehicle radio communication system 100 according to the first embodiment of the present invention is shown in FIG. That is, when each of the wireless communication terminals 10-1 to 10-15 and the wireless communication terminals 15-1 to 15-4 illustrated in FIG. 1 performs data transmission or relay, an appropriate communication path is used. The process shown in FIG. 4 is performed to select a proper route.

  Note that each of the wireless communication terminals 10-1 to 10-15 and 15-1 to 15-4 that perform the processing of FIG. 4 is the floor wireless communication network 110 and the floor wireless communication. It knows to which network 120 it belongs. In addition, the position of a shared node between the plurality of small cells AS1 to AS6 on the floor and the position of nodes connecting the networks, for example, the wireless communication terminals 10-4, 10-13, 15-3, and 15-2 in FIG. I also know.

  When each wireless communication terminal 10 in the floor wireless communication network 110 transmits data, in step S11, the presence or absence of deterioration in the quality of the wireless communication line in the own network is identified. For example, in a situation where the radio wave propagation environment deteriorates due to the influence of each occupant, the carry-on luggage of each occupant, and the structure in the passenger compartment in the floor space 21 and sufficient communication quality cannot be secured, the process goes from S11 to S15. move on. If sufficient communication quality is obtained, the process proceeds from S11 to S12.

  When each wireless communication terminal 10 in the floor wireless communication network 110 transmits data, the distance or the number of relays is compared with a predetermined threshold in the communication path to the destination terminal in step S12. If the distance or the number of relays is large, the process proceeds from S12 to S15. If the distance and the number of relays are small, the process proceeds to S13.

  If each wireless communication terminal 10 in the floor wireless communication network 110 transmits data, the priority level of the transmission target data is identified in step S13. For example, when data transmission is performed for an electrical component in which it is important to reduce the communication delay time, information indicating that the priority of the data is high is stored in the electrical component or the wireless communication terminal 10 as the transmission source. Are included in the header of the packet. Therefore, in the wireless communication terminal 10 that is the data transmission source and the wireless communication terminals 10 and 15 that relay the data, the priority of the data can be identified. When each wireless communication terminal 10 or 15 transmits data, if the priority of the data is high, the process proceeds from S13 to S15, and if the priority is low, the process proceeds from S13 to S14. Even if the data priority is high, for example, if the distance to the destination is very close, the number of relays is small, and the communication quality is good, the process proceeds from S13 to S14.

  Note that although the priority assigned to the data to be transmitted is identified in step S13 in FIG. 4, it is possible to identify the priority level depending on the transmission source included in the data. For example, when transmitting data from a transmission source to which a high priority is assigned in advance, the data can be regarded as having high priority.

  In step S14, each wireless communication terminal 10 selects a wireless communication line in the floor wireless communication network 110 and performs transmission processing. On the other hand, in step S15, each wireless communication terminal 10 or 15 performs data transmission so as to preferentially select a wireless communication line in the underfloor wireless communication network 120 over a wireless communication line in the floor wireless communication network 110. Determine the communication path.

That is, when communication line quality deteriorates due to deterioration of the radio wave propagation environment in the passenger compartment, when the distance to the destination or the number of relays is large, or when the data priority is high, wireless communication in the underfloor wireless communication network 120 is performed. The line is preferentially selected. And when using the radio | wireless communication line in the underfloor radio | wireless communication network 120, there exist the following advantages.
1. Because there are few fluctuations in the wireless communication environment, even if the required communication path cannot be secured in the vehicle interior due to the deterioration of the wireless communication environment in the vehicle interior, the communication quality can be improved by selecting the environment under the floor and performing wireless communication. A good communication path can be easily secured.
Since communication over a relatively long distance can be achieved with 2.1 wireless communication, even when the distance between the transmission source and the transmission destination is relatively large, the number of relays from the transmission source to the destination is reduced, and the data transmission delay time is reduced. Shortened.

Second Embodiment
<System configuration example>
FIG. 5 shows a configuration example of a vehicle radio communication system 100B according to the second embodiment of the present invention.

  The vehicular radio communication system 100B shown in FIG. 5 includes two sets of on-floor radio communication networks 130 and 140B. One floor wireless communication network 130 has the same network configuration as the floor wireless communication network 110 in FIG. 1 and is disposed in the vehicle interior space 21A. The other on-floor wireless communication network 140B is arranged in the engine room inner space 21B. The wireless communication terminals 10B-1, 10B-2, 10B-4, and 10B-5 in the floor wireless communication network 140 perform wireless communication within the entire engine room, that is, within the entire engine room area AL2 that is larger than the small cell. can do. The two floor wireless communication networks 130 and 140B are connected so as to communicate with each other.

  However, the vehicle interior space 21 </ b> A and the engine room internal space 21 </ b> B are partitioned by a partition wall 25 on the vehicle body 30. Since the partition wall 25 is made of a steel material as a conductor, radio waves used for wireless communication are shielded by the partition wall 25 and the floor plate 20B. Therefore, in the example shown in FIG. 5, the connection cables 18A and 18B penetrating the partition wall 25 are used to connect the two on-floor wireless communication networks 130 and 140B.

  The on-floor wireless communication network 130 shown in FIG. 5 is used for transmitting necessary signals by various data communication between various electrical components in a vehicle cabin. That is, for transmitting signals output by various switches and various sensors, transmitting / receiving signals input / output by various electronic control units (ECU), and transmitting signals for controlling on / off of various loads, etc. Used for The on-floor wireless communication network 140B is used to transmit necessary signals by data communication between various electrical components such as sensors, electronic control units, and various loads arranged in the engine room space 21B. .

  The floor wireless communication network 130 illustrated in FIG. 5 includes a plurality of wireless communication terminals 10-1 to 10-6. In FIG. 5, the radio communication terminals 10-1, 10-2, 10-3, and 10-4 form the floor small cell AS1, and the radio communication terminals 10-4, 10-5, and 10-6 are the floor small cells. A cell AS2 is formed. Further, since the wireless communication terminal 10-4 belongs to both of the adjacent floor small cells AS1 and AS2, via the wireless communication terminal 10-4, the plurality of floor small cells AS1 and AS2 are mutually connected. You can also communicate.

  In addition, the wireless communication terminals 10-1 and 10-5 of the floor wireless communication network 130 and the wireless communication terminals 10B-2 and 10B-5 of the floor wireless communication network 140B are respectively assigned as gateways between a plurality of networks. The wireless communication terminals 10-1 and 10B-2, which are gateways, are connected via a connection cable 18A, and the wireless communication terminals 10-5 and 10B-5 are connected via a connection cable 18B. Connected.

  Therefore, it is possible to communicate between the two on-floor wireless communication networks 130 and 140B via the wireless communication terminals 10-1, 10-5, 10B-2, and 10B-5 that are gateways.

  In the vehicular radio communication system 100B shown in FIG. 5, each radio communication terminal 10B-1, 10B-2, 10B-4, 10B-5 in the floor radio communication network 140B has an engine room in which the fluctuation of the radio wave propagation environment is small. Wireless communication is performed using the internal space 21B. In addition, since various devices are arranged in the engine room space 21B, the space that can be used for wireless communication may be relatively small. Smaller and less likely to cause communication failures. Therefore, a stable wireless communication path can be secured in the entire engine room area AL2. In the vehicular wireless communication system 100B of FIG. 5, for example, when the communication path in the floor wireless communication network 130 is blocked by passengers, luggage, etc., the communication path via the gateway and the floor wireless communication network 140B is used. By doing so, wireless communication can be reliably performed.

<Modification>
A modification of the second embodiment is shown in FIG.
The vehicular radio communication system 100C shown in FIG. 6 includes two sets of floor radio communication networks 130 and 140 and an under floor radio communication network 120B. One on-floor wireless communication network 130 is disposed in the vehicle interior space 21A, and the other on-floor wireless communication network 140 is disposed in the engine room space 21B. Further, an underfloor wireless communication network 120B including two wireless communication terminals 15-1 and 15-2 is formed in the underfloor space 22. The on-floor wireless communication network 130 includes a plurality of on-floor small cells AS1 and AS2 as in the configuration of FIG. Further, the on-floor wireless communication network 140 shown in FIG. 6 includes a plurality of on-floor small cells AS1B and AS2B. The floor small cell AS1B includes wireless communication terminals 10B-1, 10B-2, and 10B-3, and the floor small cell AS2B includes wireless communication terminals 10B-3, 10B-4, 10B-5, and 10B-6.

  A wireless communication path is formed between the two wireless communication terminals 15-1 and 15-2 in the entire underfloor area AL. Since each wireless communication terminal 15-1 and 15-2 has a larger transmission output than the wireless communication terminal 10, wireless communication can be performed within a wide underfloor entire area AL. Further, the connection cable 17 connects between the wireless communication terminal 10-5 assigned as the gateway of the floor wireless communication network 130 and the wireless communication terminal 15-2. The wireless communication terminal 10B-6 assigned as the gateway of the floor wireless communication network 140 and the wireless communication terminal 15-1 are connected by a wireless communication path in the small cell AS3B.

  Only the antennas of the radio communication terminals 15-1 and 15-2 are arranged in the underfloor space 22, the radio communication terminal 15-2 is arranged in the vehicle interior space 21A, and the radio communication terminal 15-1 is arranged in the engine room space 21B. You may arrange in.

  In the vehicular radio communication system 100C shown in FIG. 6, by using the underfloor radio communication network 120B, a relatively large distance can be connected by only one radio communication. In addition, since the underfloor space 22 has little fluctuation in the radio wave propagation environment, a stable high-quality wireless communication path can be secured. Therefore, it is possible to interconnect the on-floor wireless communication network 130 in the vehicle interior space 21A and the on-floor wireless communication network 140 in the engine room internal space 21B without routing a cable penetrating the partition wall 25.

  The vehicle wireless communication system 100C shown in FIG. 6 can be used as it is, for example, when connecting the interior space 21A and the luggage room of the vehicle. That is, in a general automobile, a partition also exists between the vehicle interior space 21A and the luggage room. Therefore, the vehicle interior space 21A and the luggage room are not routed without routing a cable penetrating the partition wall. It is desirable to be able to communicate with each other. Moreover, since various luggages are arranged in various forms in the luggage room according to the situation, the fluctuation of the radio wave propagation environment is relatively large. However, similarly to the vehicular wireless communication system 100C shown in FIG. 6, the underfloor wireless communication network 120B is formed using the underfloor space 22 below the vehicle interior space 21A and below the luggage room, thereby stabilizing the vehicle. A wireless communication path can be secured. Further, by using the underfloor wireless communication network 120B, it is possible to connect a relatively long distance with only one wireless communication, so it is possible to reduce the number of relays on the network and shorten the data transmission delay time. .

  As described above, the vehicle wireless communication system according to the embodiment of the present invention uses the underfloor wireless communication network 120 formed in the underfloor space 22 or the like of the automobile, so that the occupant, the carry-on of the occupant, the in-vehicle structure Wireless communication can be performed without being affected by objects. Therefore, it is possible to avoid a situation in which the quality of wireless communication is deteriorated or the communication path is interrupted, and it is difficult to cause a change in communication quality, so that a stable communication path can be secured. In addition, since the floor wireless communication network 110 with a small wireless communication range can also be used, even in an environment where a large number of electrical components are distributed in various locations in the vehicle interior, a cable that penetrates the underfloor space 22 Etc. for each electrical component, the length of other cables can be shortened, and the complexity of the structure of the wire harness and the increase in weight can be avoided.

  Further, in the communication path using the underfloor wireless communication network 120, since the wireless communication range is larger than the floor wireless communication network 110, it is possible to perform communication over a long distance with one wireless communication, and data can be reduced by reducing the number of relays. It becomes possible to reduce the transmission delay time.

  In addition, when the antenna 15a is installed on the lower arm 33 or the like, the distance between the antenna 15a and the road surface can be kept constant regardless of the vertical movement of the vehicle body 30, and road surface irregularities and obstacles on the road surface can be maintained. Interference with the antenna 15a can be prevented. In addition, since the distance between the antenna 15a and the floor plate 20 can be sufficiently increased, a favorable radio wave propagation environment can be obtained. In addition, because the radio wave propagation environment is stable, there is no need to perform special control to recognize the actual radio wave environment, or to switch antennas, and avoid delays associated with the control. And control becomes easy.

  In the vehicle radio communication system 100B shown in FIG. 5 and the vehicle radio communication system 100C shown in FIG. 6, the two on-floor radio communication networks 130 and 140 are connected to each other without being affected by the partition wall 25. Can connect.

Here, the features of the above-described embodiments of the vehicle wireless communication system according to the present invention are summarized and listed in the following [1] to [5], respectively.
[1] A first wireless communication network (floor wireless communication network 110) including a plurality of wireless communication terminals (10-1 to 10-15) disposed in a first region (floor space 21) on a vehicle;
The second on-vehicle includes a plurality of wireless communication terminals (15-1 to 15-4), and at least one of the antennas (15a) has less variation in the wireless communication environment than the first region. A second wireless communication network (underfloor wireless communication network 120) disposed in the area (underfloor space 22),
With
The first wireless communication network and the second wireless communication network are configured to be able to communicate with each other via a wireless or wired communication path (connection cables 16 and 17).
A vehicle radio communication system (100) characterized by the above.

[2] The second region is a space under the floor of the vehicle.
The vehicular radio communication system according to [1] above.

[3] The plurality of wireless communication terminals (10-1 to 10-15) in the first wireless communication network are in a predetermined small cell (floor small cells AS1 to AS6) that is at least smaller than the space on the vehicle. Wireless communication in range,
The plurality of wireless communication terminals (15-1 to 15-4) in the second wireless communication network are larger than the small cell and are equal to or smaller than the space on the vehicle (underfloor entire area AL ) Wireless communication,
The vehicular wireless communication system according to [1] or [2] above, wherein

[4] At least one antenna (15a) of the plurality of wireless communication terminals in the second wireless communication network is fixed to a lower arm (33) of a suspension of the wheel,
The vehicle radio communication system according to any one of the above [1] to [3].

[5] A communication control unit that performs communication by preferentially selecting one of the communication path of the first wireless communication network and the communication path of the second wireless communication network according to the type of data to be transmitted. (S13 to S15)
The vehicle radio communication system according to [3] above, wherein

10, 10-1 to 10-15 Wireless communication terminal 10a, 15a Antenna 15, 15-1, 15-2, 15-3, 15-4 Wireless communication terminal 16, 17, 18A, 18B Connection cable 20, 20B Floor board 21 Floor space 21A Car interior space 21B Engine room space 22 Floor space 25 Bulkhead 30 Car body 31 Wheels 32 Shock absorber 33 Lower arm 100, 100B, 100C Vehicle wireless communication system 110, 130, 140, 140B Floor wireless communication network 120 Floor wireless communication Network AS1, AS2, AS3, AS4, AS5, AS6 Small cell on the floor AL Whole area under the floor AL2 Whole area of the engine room

Claims (5)

A first wireless communication network including a plurality of wireless communication terminals arranged in a first area on the vehicle;
A second wireless communication network including a plurality of wireless communication terminals, at least one of which is arranged in the second region on the vehicle, in which fluctuations in the wireless communication environment are small compared to the first region When,
With
The first wireless communication network and the second wireless communication network are configured to be able to communicate with each other via a wireless or wired communication path.
Wireless communication system for vehicles. The second region is a space under the floor of the vehicle;
The vehicle wireless communication system according to claim 1. The plurality of wireless communication terminals in the first wireless communication network perform wireless communication in a range within a predetermined small cell smaller than a space on the vehicle,
The plurality of wireless communication terminals in the second wireless communication network perform wireless communication in a range larger than the small cell and equal to or smaller than the space on the vehicle.
The vehicular wireless communication system according to claim 1 or 2, characterized in that At least one antenna of the plurality of wireless communication terminals in the second wireless communication network is fixed to a lower arm of a wheel suspension;
The vehicle radio communication system according to any one of claims 1 to 3. In accordance with the type of data to be transmitted, a communication control unit that performs communication by preferentially selecting one of the communication path of the first wireless communication network and the communication path of the second wireless communication network,
The vehicle radio communication system according to claim 3.

Images