JP2007318540A - Radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a radio communication system which suppresses the occurrence of interference with the outside of a vehicle while avoiding the occurrence of shadowing if the system is constructed inside the vehicle. <P>SOLUTION: The radio communication system is a radio communication system constructed in a vehicle, and is provided with: a base station (1) provided with an antenna (11) and a leakage coaxial cable (12) that functions as an antenna; and terminal stations (2-1, 2-2 and 2-n) for communicating with the base station through an antenna or a leakage coaxial cable. The power level of a signal transmitted from the antenna (11) is made the level that dose not interfere with the outside of the vehicle, and the leakage coaxial cable (12) is installed in an area inside the vehicle, the area which a transmission signal from the antenna does not reach directly. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wireless communication system built in a vehicle, and more particularly to a wireless communication system capable of avoiding shadowing in the vehicle.

  In recent years, devices installed in vehicles have increased, and an increase in the number of parts such as wires and connectors for connecting devices has been a problem. In particular, there has been a problem of how to efficiently arrange control lines (communication lines for transmitting and receiving signals for controlling devices), which have been increased along with higher functionality of devices, in a limited space.

  Here, in order to solve the problem of the increase in the number of parts, a technique for reducing the number of parts by wirelessly transmitting control signals between devices (by wireless communication) is disclosed in Patent Document 1 below. It is shown. According to the following Patent Document 1, a leaky coaxial cable (LCX) is connected to an ECU (Electronic Control Unit) instead of a normal antenna, and the ECU is placed close to the leaky coaxial cable installed in the vehicle. Place each device. Thereby, transmission / reception of control signals by wireless communication between the ECU and each device is realized, and the number of parts is reduced.

JP-A-11-266251

  In a communication system composed of a base station and a terminal station installed in a vehicle, when trying to cover everything in the vehicle with a single base station, a shadowing problem exists and a specific terminal station (e.g., Radio waves may not reach the terminal station installed in the bumper. This problem itself can be solved by increasing the transmission power of the base station, but this time another problem arises in that it interferes with other vehicles (other communication systems) outside the vehicle.

  In addition, if the technique using the leaky coaxial cable described in Patent Document 1 is used, it is possible to solve a part of the problem, such as suppressing the occurrence of a problem that causes interference with other communication systems. , Hoods, trunks, and all shadowing measures for living spaces in the vehicle are not fully resolved.

  Further, a hidden terminal problem occurs between a base station that performs communication using a leaky coaxial cable and each terminal station. However, in Patent Document 1, the solution is not disclosed.

  The present invention has been made in view of the above, and obtains a wireless communication system capable of suppressing the occurrence of interference outside the vehicle while avoiding the occurrence of shadowing when built in the vehicle. For the purpose.

  Another object of the present invention is to obtain a wireless communication system capable of solving the hidden terminal problem between the base station and each terminal station.

  In order to solve the above-described problems and achieve the object, the present invention is a wireless communication system built in a vehicle, and includes a base station including an antenna and a leaky coaxial cable functioning as an antenna, and the antenna or A terminal station that communicates with the base station via the leaky coaxial cable, and a power level of a signal transmitted from the antenna is set to a level that does not cause interference outside the vehicle, and the leaky coaxial cable is connected to the antenna from the antenna. It is characterized in that it is installed in an area in the vehicle where the transmission signal cannot reach directly.

  According to the present invention, there is an effect that it is possible to realize a wireless communication system capable of suppressing the occurrence of interference outside the vehicle while avoiding the occurrence of shadowing in the vehicle.

  Embodiments of a wireless communication system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration example of a first embodiment of a wireless communication system according to the present invention. This wireless communication system includes a base station 1 and terminal stations 2-1, 2-2, and 2-n. The base station 1 includes an antenna 11 and a leaky coaxial cable 12 that functions as an antenna, and each of the terminal stations (terminal stations 2-1, 2-2, 2-n) via the antenna 11 or the leaky coaxial cable 12. ). 1 shows an example in which the base station 1 communicates with the terminal station 2-1 via the antenna 11, and communicates with the terminal stations 2-2 and 2-n via the leaky coaxial cable 12. Is shown.

  FIG. 2 is a diagram illustrating a configuration example of the first embodiment of the base station included in the wireless communication system according to the present invention. In addition to the antenna 11 and the leaky coaxial cable 12, the base station 1 includes a wired I / F unit 13 that is a wired I / F (interface) for connecting to Ethernet (registered trademark) and the like, and signal transmission / reception processing Etc., a baseband / MAC function unit 14, an antenna / leakage coaxial cable switching unit 15 for selecting a signal transmission path, an antenna / leakage coaxial cable input coupling unit 16 for coupling two received signals, a memory, etc. And an antenna control unit 17 that performs antenna switching control. Note that the base station 1 can connect to a terminal capable of vehicle-to-vehicle communication or road-to-vehicle communication using the wired I / F 13 to capture data from outside the vehicle.

  3 and 4 are diagrams showing a configuration example of a terminal station included in the wireless communication system according to the present invention. The terminal station illustrated in FIG. 3 is configured to be connectable to an antenna 21, a baseband / MAC function unit 22 that performs signal transmission / reception processing, and a general-purpose I / F such as Ethernet (registered trademark). A wired I / F unit 23 for connection to a personal computer. The terminal station having the configuration shown in FIG. 3 is a terminal station that is assumed to be installed in a living space in a vehicle.

  On the other hand, the terminal station shown in FIG. 4 includes an antenna 21, a baseband / MAC function unit 24 that performs signal transmission / reception processing, and an I / F for vehicle control such as CAN (Controller Area Network). The vehicle control unit I / F unit 25 is configured to be connectable to a control unit such as a brake control and a lamp control. The terminal station having the configuration shown in FIG. 4 is a terminal station that is assumed to be installed in the vicinity of a control unit such as in a hood.

  It should be noted that the terminal station installation position is only an example, and the terminal station shown in FIG. 3 may be installed in a hood or the like, or the terminal station shown in FIG. 4 may be installed in a living space. Also good. The terminal station may be configured to include both the wired I / F unit 23 and the automobile control unit I / F unit 25.

  A communication control operation when the base station configured as described above communicates with a terminal station will be described with reference to the drawings, focusing on the operation of the base station. Note that the communication control operation of the base station is the same when performed with either the terminal station having the configuration shown in FIG. 3 or the terminal station having the configuration shown in FIG.

  First, when the base station transmits data to the terminal station, the baseband / MAC function unit 14 checks the transmission direction with respect to the antenna control unit 17. In the first data transmission, the antenna control unit 17 determines whether the terminal station is in the cover area of the antenna 11 (hereinafter referred to as the antenna area) or the cover area of the leaky coaxial cable 12 (hereinafter referred to as the leaky coaxial cable area). Therefore, the baseband / MAC function unit 14 is instructed to distribute and transmit data. The baseband / MAC function unit 14 follows the data distribution instruction received from the antenna control unit 17 and performs continuous transmission of data via both the antenna 11 and the leaky coaxial cable 12. Control.

  Next, when the terminal station transmits data to the base station, the transmitted data is received via the antenna 11 or the leaky coaxial cable 12 and input to the antenna / leakage coaxial cable input coupling unit 16. The antenna / leaky coaxial cable input coupling unit 16 couples the input from the antenna 11 and the input from the leaky coaxial cable 12 to obtain received data. The antenna / leakage coaxial cable input coupling unit 16 adds the antenna identification information indicating whether the received data is received via the antenna 11 or the leaky coaxial cable 12 to the reception data and adds the reception data with identification information. Is generated. The generated reception data with identification information is passed to the baseband / MAC function unit 14.

  When the baseband / MAC function unit 14 receives the reception data with identification information, the baseband / MAC function unit 14 extracts the antenna identification information therein, and uses the antenna identification information together with the terminal identification information (for example, using the MAC address) as the antenna control unit 11. To notify. The received data separated from the antenna identification information is transmitted to other devices via the wired I / F unit 13 as necessary.

  The antenna control unit 11 stores the antenna identification information and terminal information received from the baseband / MAC function unit 14 in association with each other. Thereafter, when transmitting data to the terminal indicated by the stored terminal information (when receiving a transmission direction query of data to be transmitted to the terminal from the baseband / MAC function unit 14), the antenna control unit 11 stores the data in association with each other. The data transmission direction is instructed based on the antenna identification information.

  In the description of the communication control operation of the base station, the operation of the antenna control unit 17 having a learning function (a function of performing a distribution transmission instruction only at the first transmission and storing a data reception path as a communication path) will be described. However, the learning operation may be omitted by the antenna control unit 17 storing the information of the terminal station located in the antenna area and the information of the terminal station located in the leaky coaxial cable area in advance in a memory.

  In the base station that performs such a communication control operation, the power of the signal transmitted from the antenna 11 is set to a level that does not interfere with other communication devices (communication systems) outside the vehicle in consideration of the installation location. . The leaky coaxial cable 12 is installed in a location where a transmission signal from the antenna 11 in the vehicle does not reach directly, and exchanges data with a terminal station located in an area that the antenna 11 cannot cover. As a result, it is possible to suppress the occurrence of shadowing in the vehicle while preventing the occurrence of interference outside the vehicle.

  As described above, in this embodiment, the base station constituting the communication system includes the antenna and the leaky coaxial cable for transmitting / receiving data to / from the subordinate terminal station, and can directly receive the signal from the antenna. The terminal station communicates via an antenna, while the terminal station located in an area where signals from the antenna cannot be directly received is communicated via a leaky coaxial cable. Accordingly, it is possible to realize a wireless communication system that can suppress the occurrence of interference outside the vehicle while avoiding the occurrence of shadowing in the vehicle.

Embodiment 2. FIG.
Next, the radio communication system according to the second embodiment will be described. In the present embodiment, a communication control operation when the base station permits transmission to a terminal station located in the antenna area and a terminal station located in the leaky coaxial cable area will be described.

  The configuration of the radio communication system according to the present embodiment is the same as that of the radio communication system according to the first embodiment described above. FIG. 5 is a diagram illustrating a configuration example of Embodiment 2 of a base station included in a wireless communication system according to the present invention. The base station of the present embodiment replaces the antenna / leakage coaxial cable switching unit 15 and the antenna / leakage coaxial cable input coupling unit 16 included in the base station of the first embodiment described above, with an antenna / leakage coaxial cable switching unit 15a. Is provided. The antenna / leakage coaxial cable switching unit 15a transmits and receives signals via the antenna 11 and the leaky coaxial cable. That is, the antenna / leakage coaxial cable switching unit 15a has both functions of the antenna / leakage coaxial cable switching unit 15 and the antenna / leakage coaxial cable input coupling unit 16 shown in the first embodiment. Since the other parts are the same as those of the base station of Embodiment 1, the same reference numerals are given and the description thereof is omitted. The configuration of the terminal station is the same as that of the terminal station of the first embodiment.

  A communication control operation when the base station configured as described above communicates with a terminal station will be described with reference to FIGS. FIG. 6 is a diagram illustrating an example of an operation in which the base station of the second embodiment permits each terminal station to transmit.

  As shown in FIG. 6, the base station 1 sets information indicating a period (LCX transmission / reception period) in which transmission of a terminal station located in the leaky coaxial cable area is permitted in a beacon, and the terminal station in the antenna area. And periodically transmitted to the terminal stations in the leaky coaxial area, that is, all the terminal stations in the system.

  The terminal station (for example, the terminal station 2-2) located in the leaky coaxial cable area is based on the transmission timing of each beacon, and in the LCX transmission / reception period indicated by the information set in the beacon transmitted at the reference timing, Communicates with the base station 1 (transmits data to the base station 1). Further, the period from the end of the LCX transmission / reception period to the next beacon transmission timing is defined as the antenna transmission / reception period, and the terminal station (for example, the terminal station 2-1) located in the antenna area communicates with the base station 1 during this period. Do. The base station 1 performs the same operation as the base station described in the first embodiment when communicating with a specific terminal station for the first time, and transmits data (used when communicating with each terminal station). Route).

  Hereinafter, the base station 1 and the terminal station located in the leaky coaxial cable area communicate with the terminal station located in the leaky coaxial cable area during the LCX transmission / reception period indicated by the information set in the beacon that is periodically transmitted. In a period other than the above, the base station 1 and the terminal station located in the antenna area perform communication.

  In this embodiment, a beacon in which information indicating an LCX transmission / reception period is set is transmitted, but a beacon in which information indicating an antenna transmission / reception period is set may be transmitted.

  Thus, in the present embodiment, each terminal station communicates with the base station according to the transmission permission period (corresponding to the LCX transmission / reception period) indicated by the information set in the beacon. As a result, the base station allocates a period (opportunity) that permits transmission to terminals in an area where there are more terminal stations in the antenna area and the leaky coaxial cable area. Communication opportunities can be assigned flexibly.

Embodiment 3 FIG.
Next, the radio communication system according to the third embodiment will be described. In the present embodiment, the communication control operation when the base station permits transmission to the terminal station located in the antenna area and the terminal station located in the leaky coaxial cable area will be described in more detail.

  The configuration of the radio communication system of the present embodiment is the same as that of the radio communication system of the second embodiment described above. Further, the configurations of the base station and terminal station are the same as those of the base station and terminal station of the second embodiment. A communication control operation when the base station of the present embodiment communicates with the terminal station will be described with reference to FIG. 1 and FIG. FIG. 7 is a diagram illustrating an example of an operation in which the base station of the third embodiment permits each terminal station to transmit.

  As shown in FIG. 7, the base station 1 transmits and receives an operation switching cycle (a reference cycle of a period during which transmission is permitted to the terminal station in the antenna area and a period during which transmission is permitted to the terminal station in the leaky coaxial cable area) to the beacon. Set a period switching bit pattern (a bit pattern that indicates a period during which transmission is permitted to terminal stations in the antenna area and a period during which transmission is permitted to terminal stations in the leaky coaxial cable area) and is transmitted to the terminal stations in the system. To do. The base station 1 and each terminal station perform communication according to the operation switching cycle and the transmission / reception period switching bit pattern set in the beacon.

  Here, FIG. 7 shows that in a system in which the beacon transmission cycle is 100 ms, the base station 1 switches the beacon # 1 (Beacon # 1) to “(operation) switching cycle = 10 ms” and “switching bit pattern of (transmission and reception period) = In this example, “010110010” is set and transmitted. In this example, since the period in which the switching bit pattern is “0” corresponds to the LCX transmission / reception period, the reference timing (0 ms) to 10 ms, 20 to 30 ms, 60 to 80 ms, 90 when the transmission timing of beacon # 1 is used as a reference. ˜100 ms is the LCX transmission / reception period, and the remaining period is the antenna transmission / reception period.

  Therefore, the terminal station located in the antenna area that received beacon # 1 communicates with the base station in a period after 30 ms has elapsed from the reference timing and before 60 ms has elapsed. In addition, the terminal station located in the leaky coaxial cable area communicates with the base station in a period after 60 ms from the reference timing and before 80 ms.

  Thus, in the present embodiment, each terminal station communicates with the base station according to the transmission permission period indicated by the information set in the beacon. As a result, the base station can flexibly allocate to each terminal station, for example, by assigning more time to allow transmission to terminals in an area where there are more terminal stations in the antenna area and leaky coaxial cable area. Communication opportunities can be assigned.

Embodiment 4 FIG.
Next, the radio communication system according to the fourth embodiment will be described. In the present embodiment, a communication control operation when a base station permits transmission to each terminal station, and a communication control operation using a method different from the above-described third embodiment will be described.

  The configuration of the radio communication system of the present embodiment is the same as that of the radio communication system of the second embodiment described above. Further, the configurations of the base station and terminal station are the same as those of the base station and terminal station of the second embodiment. A communication control operation when the base station of the present embodiment communicates with the terminal station will be described with reference to FIG. 1 and FIG. FIG. 8 is a diagram illustrating an example of an operation in which the base station of the fourth embodiment permits each terminal station to transmit. In the present embodiment, the base station uses a unique frame to notify each terminal station of a period during which transmission is permitted (LCX transmission / reception period, antenna transmission / reception period).

  As shown in FIG. 8, the base station 1 uses a unique frame (for example, a frame in which the data type is a data frame or a control frame and a sub-type is set with an empty area value (undefined value)) as a terminal in the antenna area. The antennas are sequentially switched and transmitted to a station (for example, the terminal station 2-1) and a terminal station (for example, the terminal station 2-2) in the leaky coaxial cable area. In this unique frame, an identifier for identifying the LCX transmission / reception period and the antenna transmission / reception period and the transmission / reception time (the length of each period) are set.

  The terminal station located in the leaky coaxial cable area checks the identifier when receiving the unique frame. If the identifier indicates the LCX transmission / reception period, it is specified in the unique frame after receiving the unique frame. During the period until the transmission / reception time elapses, communication with the base station 1 is performed.

  Similarly, if the identifier set in the unique frame indicates the antenna transmission / reception period, the terminal station located in the antenna area until the transmission / reception time specified in the unique frame elapses after reception of the unique frame. In this period, communication with the base station 1 is performed.

  Thus, in this embodiment, the base station individually permits transmission by transmitting to each terminal station a unique frame in which information on the period during which transmission is permitted is set, and each terminal station In the period according to the information set in the received unique frame (information indicating a period during which transmission to each terminal station is permitted), communication with the base station is performed. Thereby, the base station can flexibly allocate a communication opportunity to each terminal station.

Embodiment 5 FIG.
Next, the radio communication system according to the fifth embodiment will be described. In the present embodiment, a base station that does not require the antenna switching control (LCX transmission / reception period and antenna transmission / reception period switching control operation) required in the communication control operations of the above-described second to fourth embodiments will be described.

  The configuration of the radio communication system according to the present embodiment is the same as that of the radio communication system according to the first embodiment described above. FIG. 9 is a diagram illustrating a configuration example of a base station included in the radio communication system according to the fifth embodiment of the present invention. The base station of the present embodiment includes a wired I / F unit 13 and baseband / MAC function units 18 and 19. The configuration of the terminal station is the same as that in the first embodiment.

  The baseband / MAC function unit 18 performs transmission / reception processing of signals exchanged with the terminal station via the antenna 11, and the baseband / MAC function unit 19 exchanges with the terminal station via the leaky coaxial cable 12. Performs signal transmission and reception processing. That is, the base station includes means (baseband / MAC function unit) for performing transmission / reception processing independently for the antenna 11 and the leaky coaxial cable 12, so that complicated antenna switching control is not required. Moreover, mutual interference can be avoided by assigning the antenna 11 and the leaky coaxial cable 12 at different frequencies.

  As described above, by constructing a wireless communication system using the base station having the configuration shown in this embodiment, it is possible to avoid complication of communication control processing. Further, by making the frequency used at the time of communication via the antenna and the frequency used at the time of communication via the leaky coaxial cable different from each other, it is possible to avoid that both communications interfere with each other.

Embodiment 6 FIG.
Next, the radio communication system according to the sixth embodiment will be described. In the wireless communication systems according to the first to fifth embodiments described above, there is a problem in that the base station and the terminal stations located in the leaky coaxial cable area are hidden from each other and a collision occurs. Therefore, in this embodiment, a radio communication system capable of avoiding this hidden terminal problem will be described.

  The configuration of the radio communication system according to the present embodiment is the same as that of the radio communication system according to the first embodiment described above. Further, the configurations of the base station and terminal station are the same as those of the base station and terminal station of the first embodiment. A communication control operation performed by the base station of this embodiment to avoid the hidden terminal problem will be described with reference to FIG. In addition, FIG. 10 is a figure for demonstrating the operation | movement which the base station of Embodiment 6 controls each terminal station of a leaky coaxial cable area.

  The base station, for example, has a null payload (0) for the terminal station located in the leaky coaxial cable area, for example, the subtype is set to any value of a free area (a range of “1000 to 1111” in the bit pattern). Send the data frame. At this time, a value larger than the specified value is set in the NAV (Network Allocation Vector) of the duration field included in the MAC header of the data frame.

  The terminal station that has received the data frame in the unique format configured as described above confirms whether or not the data frame addressed to itself has been received based on the MAC address. As a result of the confirmation, if it is determined that the data frame is addressed to itself, if there is data to be transmitted to the base station, transmission is performed during the period indicated by the NAV included in the received data frame. That is, the base station permits transmission to the terminal station specified by the MAC address during the period indicated by the NAV included in the data frame.

  On the other hand, if it is determined that a data frame not addressed to itself has been received, the terminal station performs an operation in accordance with the IEEE standard. That is, a terminal station that is not designated by the MAC address of the received data frame (not permitted to transmit) does not transmit during the period indicated by the NAV value included in the received data frame.

  In the example illustrated in FIG. 10, first, the base station permits transmission to the terminal station #A, and only the terminal station #A permitted to transmit performs transmission. Next, the base station permits transmission to the terminal station #A.

  As described above, in the present embodiment, the data frame is used to generate a unique format frame, and the base station individually permits transmission to the terminal station located in the leaky coaxial cable area. The station transmits only when a unique frame that permits transmission is received. Thereby, it can avoid that the transmission from each terminal collides.

Embodiment 7 FIG.
Next, the radio communication system according to the seventh embodiment will be described. In the present embodiment, the communication control operation performed by the above-described base station of the sixth embodiment will be described in more detail. The configuration of the radio communication system according to the present embodiment is the same as that of the radio communication system according to the sixth embodiment described above. Further, the configurations of the base station and terminal station are the same as those of the base station and terminal station of the sixth embodiment.

  A communication control operation performed by the base station according to the present embodiment will be described with reference to FIG. 11, FIG. 12, and FIG. FIG. 11 is a diagram for explaining a polling scheduling operation performed by the base station according to the seventh embodiment. 12 and 13 are diagrams for explaining an operation (communication control operation) in which the base station of the seventh embodiment controls each terminal station in the leaky coaxial cable area.

  At the time of L2 (layer 2) authentication in the connection process with respect to the base station, the terminal station notifies the base station of an information element indicating a priority / non-priority type as additional information. In the base station, upon receiving notification of additional information indicating the priority / non-priority type from the terminal station at the time of L2 authentication in the connection process, the scheduling registration unit in the baseband / MAC function unit 14 receives priority / non-priority. An entry of the terminal station is generated based on the type and the MAC address, and is registered in the scheduler unit (see FIG. 11). Specifically, if the priority / non-priority type notified from the terminal station is “priority”, the scheduling registration unit registers this terminal on the priority schedule side of the scheduler unit. On the other hand, if the priority / non-priority type is “non-priority”, this terminal is registered on the non-priority schedule side.

  The scheduler unit polls the terminal stations registered in the priority schedule by the scheduling registration unit in order. Then, as a result of polling the terminal stations registered in the priority schedule, the scheduler unit polls the terminal stations registered in the non-priority schedule only when no transmission request is received from any terminal station. After polling the terminal station registered in the non-priority schedule, the process returns to the polling operation of the terminal station registered in the priority schedule.

  FIG. 12 is a diagram illustrating an operation example when the base station polls each terminal station. As shown in FIG. 12, the scheduler unit (base station) receives the DIFS (DCF (= Distributed Coordination Function) without receiving data from the terminal station after receiving data from the terminal station or after starting polling. ) Interframe Space: When the time corresponding to the distributed control frame interval elapses, polling for the next terminal station is started.

  Further, the scheduler unit may perform polling by an operation as shown in FIG. 13 using a unique frame defined in the system. Specifically, when the scheduler unit (base station) receives data from the terminal station, or receives a unique frame indicating the presence / absence of data from the terminal station and the content is “no data”, Start polling the next terminal station. As a result, it is not necessary to wait for the DIFS time to elapse when there is no data, and polling of the next terminal station can be started immediately, so that polling can be performed efficiently.

  Note that the operation shown in FIG. 12 and the operation shown in FIG. 13 may be performed together. That is, polling for the next terminal station may be started when data is received from a terminal station, when the DIFS time has elapsed, or when a unique frame indicating “no data” is received. Thus, even when a unique frame indicating “no data” cannot be received, it is possible to shift to polling for the next terminal station after the DIFS time has elapsed.

  As described above, in the present embodiment, the base station performs polling scheduling based on the priority of the terminal station (information indicating whether or not the terminal is to perform polling preferentially) at the time of layer 2 authentication. Based on the results, it was decided to poll each terminal station. As a result, it is possible to realize priority control by classifying terminals to be polled.

  As described above, the wireless communication system according to the present invention is useful for a wireless communication system built in a vehicle, and is particularly suitable for a wireless communication system capable of avoiding shadowing in a vehicle.

It is a figure which shows the structural example of Embodiment 1 of the radio | wireless communications system concerning this invention. It is a figure which shows the structural example of Embodiment 1 of the base station contained in the radio | wireless communications system concerning this invention. It is a figure which shows the structural example of Embodiment 1 of the terminal station contained in the radio | wireless communications system concerning this invention. It is a figure which shows the structural example of Embodiment 1 of the terminal station contained in the radio | wireless communications system concerning this invention. It is a figure which shows the structural example of Embodiment 2 of the base station contained in the radio | wireless communications system concerning this invention. FIG. 10 is a diagram illustrating an example of an operation in which the base station of the second embodiment permits each terminal station to transmit. FIG. 10 is a diagram illustrating an example of an operation in which the base station of the third embodiment permits each terminal station to transmit. FIG. 10 is a diagram illustrating an example of an operation in which the base station of the fourth embodiment permits each terminal station to transmit. It is a figure which shows the structural example of Embodiment 5 of the base station contained in the radio | wireless communications system concerning this invention. FIG. 10 is a diagram for explaining an operation in which the base station of the sixth embodiment controls each terminal station in the leaky coaxial cable area. FIG. 18 is a diagram for explaining a polling scheduling operation performed by the base station of the seventh embodiment. FIG. 15 is a diagram for explaining an operation (communication control operation) in which the base station of the seventh embodiment controls each terminal station in the leaky coaxial cable area. FIG. 15 is a diagram for explaining an operation (communication control operation) in which the base station of the seventh embodiment controls each terminal station in the leaky coaxial cable area.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base station 2-1, 2-2, 2-n Terminal station 11, 21 Antenna 12 Leaky coaxial cable 13 Wired I / F part 14, 18, 19, 24 Baseband / MAC function part 15, 15a Antenna / leaky coaxial Cable switching unit 16 Antenna / leaky coaxial cable input coupling unit 17 Antenna control unit 25 Automotive control unit I / F unit

Claims (9)

A wireless communication system built in a vehicle,
A base station with an antenna and a leaky coaxial cable that functions as an antenna;
A terminal station that communicates with the base station via the antenna or the leaky coaxial cable;
With
A wireless communication characterized in that a power level of a signal transmitted from the antenna is set to a level that does not cause interference to the outside of the vehicle, and the leaky coaxial cable is installed in an area in the vehicle where the transmission signal from the antenna does not reach directly. system. The base station
When communicating with a specific terminal station, the same signal is transmitted using the antenna and the leaky coaxial cable at the first transmission,
When a response signal for the initial transmission is received via the antenna or the leaky coaxial cable, a signal is transmitted to the terminal station using the antenna or the leaky coaxial cable that has received the response signal. The wireless communication system according to claim 1. The base station periodically transmits a beacon in which additional information indicating a period during which transmission using the antenna is permitted and / or additional information indicating a period during which transmission using the leaky coaxial cable is permitted is set,
3. The wireless communication system according to claim 1, wherein each terminal station communicates with the base station during a period indicated by additional information set in the beacon. The base station transmits a signal (unique frame) in a unique format in which additional information indicating a period during which transmission using the antenna is permitted or additional information indicating a period during which transmission using the leaky coaxial cable is permitted is set. Transmit to each terminal station via the antenna and the leaky coaxial cable,
3. The wireless communication system according to claim 1, wherein each terminal station communicates with the base station during a period indicated by additional information set in the unique frame.   The base station and the terminal station use different frequencies so as not to interfere with each other in communication performed via the antenna and communication performed via the leaky coaxial cable. The wireless communication system according to 1 or 2. The base station transmits a signal (transmission permission frame) in a unique format in which information indicating a period during which transmission is permitted (transmission permission period) is set via the leaky coaxial cable,
The terminal station, when receiving a transmission permission frame addressed to itself, transmits to the base station during a transmission permission period indicated by information set in the transmission permission frame. Or the radio | wireless communications system of 2. The base station
The transmission permission frame destined for each terminal station located in an area (leakage coaxial cable area) that communicates via the leaky coaxial cable is individually generated and transmitted,
The wireless communication system according to claim 6, further comprising polling a destination terminal station of the transmission permission frame individually in a transmission permission period indicated by information set in the transmission permission frame.   Further, the base station, based on the priority information (information indicating either priority or non-priority) of each terminal station acquired in the connection process with each terminal station located in the leaky coaxial cable area, The wireless communication system according to claim 7, wherein the transmission permission frame is transmitted so as to preferentially poll the terminal station that is “.”   The base station, when data reception from the terminal station that is polling is completed, when the transmission permission period indicated by the information set in the transmission permission frame has passed, or from the terminal station that is polling 9. The wireless communication system according to claim 7, wherein a terminal station to be polled is changed when a signal indicating that transmission data does not exist is received.

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