JP2002271245A - Road wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economical, efficient, and reliable wireless communication system in which wireless zones are developed serially, such as a speedway. SOLUTION: A plurality of wireless base stations are arranged serially for covering a linear wireless zone, and the wireless base stations are provided with first and second antennas for wirelessly communicating with adjacent wireless base stations and a third antenna for wirelessly communicating with a mobile station, so that data received by the wireless base station can be repeated and transmitted via the adjacent wireless base stations. Also, this system is provided with a first host station connected to the first wireless base station among those wireless base stations through a wire or wirelessly, so that data between the mobile station and the first host station can be repeated and transmitted through those wireless base stations which exist between the first wireless base station, and the second wireless base station, which wirelessly communicates with the mobile station.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system for providing a communication service to a mobile user.
In particular, in a wireless communication system in which service areas are developed in tandem like an expressway, it is possible to construct an economical system and realize efficient and highly reliable communication.

[0002]

2. Description of the Related Art Existing PDC (Personal Digital Cellul
ar) or a mobile communication system such as PHS (Personal Handy phone System), without allocating the same frequency to adjacent cells, and by separating a radio base station that reuses frequency by a certain distance or more, the cells are planar The cellular system to arrange is adopted. This method is an effective method for efficiently using a finite radio frequency. Further, since different frequencies are used in adjacent cells, switching between frequencies used by mobile stations enables inter-cell movement (handover) without disconnection of communication.

[0003] Intelligent Transportation System (Intelligent Tran
sport Systems (ITS) uses advanced information and communication technology to build a system that integrates people, roads, and vehicles, to enhance navigation systems, establish automatic toll collection systems for toll roads, etc. It aims to support safe driving, optimize traffic management, and improve the efficiency of road management. VICS (Vehicle Information and Communic) is a system already realized as part of ITS.
ation System). VICS is a system that realizes one-way road-to-vehicle communication from the road to the car. Three types of FM multiplexing, radio beacon, and optical beacon are used according to each application.
Media is being used. A radio beacon used for short-range communication on a highway connects a radio base station installed along a road with a center system by wire, thereby enabling road traffic information to be provided to mobile users.

[0004] As an ITS access transmission method, application of a radio on fiber (ROF) is being studied. ROF is a technique for transmitting a light intensity modulated signal without demodulating a wireless signal as it is. This technology
When applied to ITS, an optical fiber is used to connect wireless base stations installed in tandem along the road, enabling information transmission over the optical fiber without demodulating wireless signals at the wireless base station. Becomes Therefore, a modem is not required in the wireless base station, and effects such as downsizing of equipment and improvement of reliability can be obtained.

[0005] 2.4 GHz ISM (Industrial, Scientific
and Medical: industrial science and medical) Wireless LAN using band
The system has been realized. The wireless LAN system has attracted attention as an outdoor wireless access means because it requires no license for use and does not require a line usage fee. However, it has a property that it is susceptible to interference from ISM devices such as microwave ovens, medical devices, and amateur radios using the frequency of 2.4 GHz. Therefore, the influence of interference is reduced by using a spread spectrum method that is resistant to interference as a modulation method.

[0006]

SUMMARY OF THE INVENTION However, at present,
In a mobile communication system such as PDC or PHS, a two-dimensional cell arrangement is performed, and a plurality of radio base stations arranged in a cell have one radio base station.
A star-type network configuration is provided that is directly connected to two radio control stations. Therefore, there is a problem that as the number of connections of the radio base stations increases, the cost for constructing a communication infrastructure between the radio control station and the radio base stations increases.

In the mobile communication system, when a user moves between cells, the mobile station must perform frequency switching processing. Specifically, the mobile station monitors the radio wave level from a plurality of radio base stations, and when the radio wave level from another radio base station different from the radio base station that is performing communication becomes stronger, Processing for switching the frequency is required. Further, the radio base station side needs a mechanism for notifying the mobile station of the frequency channel used for communication. Furthermore, when the mobile user moves at high speed, the process of switching the frequency at high speed is performed, so that there is a problem that high-immediate control is required.

In a wireless communication system widely considered in ITS, it is assumed that a wired line such as an optical fiber is used to connect wireless base stations arranged in cascade. For this reason, there is a problem that the cost for constructing the communication infrastructure, such as laying of a wired line, increases.

A wireless LAN system using the 2.4 GHz ISM band uses a spread spectrum method, which is resistant to interference, as a modulation method in order to reduce interference from ISM equipment. However, if multiple wireless LAN systems are used in the same area, wireless LANs using the same frequency channel
There is a problem that interference occurs between the systems, and as a result, the throughput of each system is reduced.

[0010] Accordingly, the present invention enables an economical system construction and realizes efficient and highly reliable communication in a wireless communication system in which service areas are developed in tandem like an expressway. With the goal.

[0011]

The road radio communication system of the present invention has a plurality of radio base stations arranged in tandem to cover radio zones arranged in tandem, wherein the radio base stations are adjacent to each other. Has first and second antennas for wirelessly communicating with a wireless base station and a third antenna for wirelessly communicating with a mobile station, and data received by the wireless base station is adjacent to the mobile base station. It is relayed and transmitted via a wireless base station. As a result, the cost for building the communication infrastructure can be kept low.

According to another embodiment of the present invention, there is provided a first high-order station connected by wire or wirelessly to one of a plurality of radio base stations arranged in cascade. And
The data transmission between the mobile station and the first higher-level station is the first
It is also preferable that the information is relayed and transmitted via a plurality of wireless base stations existing between the wireless base station and a second wireless base station that wirelessly communicates with the mobile station.

[0013] According to another embodiment of the present invention, when the first antenna is an antenna for relay transmission to the first higher-level station, data received by the first antenna is transmitted to the first antenna. The data transmitted to the second and third antennas and received by the second antenna are transmitted to the first antenna and transmitted to the third antenna.
It is also preferable that the data received by the first antenna is configured to be transmitted to the first antenna.

According to another embodiment of the present invention, when there are a plurality of first upper stations, and the first antenna and the second antenna are each an antenna for relay transmission to the first upper station, Data received by the first antenna is transmitted to the second and third antennas, data received by the second antenna is transmitted to the first and third antennas, and data received by the third antenna May be configured to transmit to the first and second antennas. With this, the radio base station that has received the data transmitted from the mobile station can relay the received data to a plurality of higher-level stations, so that even if a failure occurs in a device or communication path on one of the relay paths. , Communication can be continued.

According to another embodiment of the present invention, the radio base station records the identification information of the relayed data, and when the data of the same identification information is received a plurality of times, the data received from the second and subsequent times Is also preferably discarded. By performing such a filtering process, a malfunction in the communication protocol can be prevented, and the communication band between adjacent wireless base stations can be effectively used.

According to another embodiment of the present invention, a further higher second station connected to a plurality of first higher stations by wire or wirelessly.
, The plurality of (M-1) th upper stations (M
.Gtoreq.2), it is also preferable to have an M-th higher-order station connected by wire or wirelessly, and the higher-order station is configured in a hierarchical structure.

According to another embodiment of the present invention, the k-th upper station (2 ≦ k ≦ M) transmits data to a plurality of (k−1) -th upper stations when transmitting data to the mobile station. It is also preferable to transmit. Since the k-th higher-order station can relay data to a plurality of (k-1) -th higher-order stations, communication can be continued even if a failure occurs in a device and a communication path on one of the relay paths. It becomes possible.

According to another embodiment of the present invention, the higher-level station records the identification information of the relayed data. Discarding is also preferable. By performing such a filtering process, a malfunction in the communication protocol can be prevented, and an upper communication line can be effectively used.

According to another embodiment of the present invention, it is preferable that one radio zone of the same radio frequency channel is covered by a plurality of radio base stations by a carrier detection scheme. Thereby, when the mobile station moves between the radio base stations (handover), the process of switching the radio frequency channel of the mobile station becomes unnecessary. In a wireless zone that receives interference from a wireless system different from the wireless communication system, deterioration in communication quality can be prevented by using a frequency channel that is less affected by interference.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1A is a configuration diagram of an embodiment of a road radio communication system according to the present invention. In FIG. 1, L radio base stations arranged in tandem along a radio service area (a first radio base station, a second radio base station,..., And an i-th wireless base station, which is connected to the h-th wireless base station (1 ≦ h ≦ L) by wire or wireless to enable connection to an upper-level communication line. Mobile station 30 that is wirelessly connected to a base station (1 ≦ i ≦ L) and receives a communication service
It is composed of

FIG. 1b is a block diagram of a radio base station according to the present invention. The first wireless base station includes a first antenna and a first wireless device that are wirelessly connected to an adjacent wireless base station, and has a third antenna and a third antenna that are wirelessly connected to the mobile station 30. Equipped with a radio, the first radio and the third
Radios are connected via a data relay function,
The k-th wireless base station that is not connected to the first upper station (1 ≦ k
.Ltoreq.L) is the first wirelessly connected radio base station.
And a third antenna mounted with an antenna and a first wireless device and wirelessly connected to an adjacent wireless base station and mounted with a second wireless device and a mobile station 30 And a third wireless device, and the first wireless device, the second wireless device, and the third wireless device are connected via a data relay function.

However, although there is no physical distinction between the first antenna and the first radio and the second antenna and the second radio, the first antenna and the first radio are conveniently referred to as the first antenna and the first radio. It is assumed that the mobile station is connected to an adjacent wireless base station in the direction of the first upper station having a small number of relays.

The h-th station connected to the first higher-level station 10
Is equipped with a first antenna and a first wireless device that are wirelessly connected to an adjacent (h + 1) th wireless base station, and is wirelessly connected to an adjacent (h−1) th wireless base station. The mobile station 3 is equipped with a second antenna and a second radio.
0, a third antenna and a third wireless device that are wirelessly connected to each other, and the first wireless device, the second wireless device, the third wireless device, and the first upper station 10 have a data relay function. Connected through.

The first upper station 10 has a connection function 11 for connecting the h-th wireless base station to the upper communication line and performing necessary interface conversion, protocol conversion, and the like.

The mobile station 30 includes an antenna 31 and a radio 32, which are connected to the radio base station by radio, and a communication terminal 33 used by a user for communication.

FIG. 2 is a flowchart of the data relay function provided in the k-th radio base station (1 ≦ k ≦ L) not connected to the first upper station 10. S1: Determine the wireless device to which the data has been input. S2: If it is determined in S1 that the data is input from the first radio, the second radio and the third
Relays the input data to the other transceiver. S3: If it is determined in S1 that the data is input from the second wireless device, the input data is relayed to the first wireless device. S4: If it is determined in S1 that the data is input from the third wireless device, the input data is relayed to the first wireless device.

FIG. 3 is a flowchart of the data relay function provided in the h-th wireless base station connected to the first higher-level station 10. S11: Determine the wireless device to which the data has been input. S12: If it is determined in S11 that the data is input from the first wireless device, the input data is relayed to the first upper station 10. S13: If it is determined in S11 that the data is input from the second wireless device, the input data is relayed to the first upper station 10. S14: If it is determined in S11 that the data is input from the third wireless device, the input data is relayed to the first upper station 10. S15: If it is determined in S11 that the data is an input from the first upper station 10, the input data is relayed to the first wireless device, the second wireless device, and the third wireless device.

FIG. 4 is a block diagram showing the structure of the mobile station 30 to the first upper station 10.
5 is a flowchart when data is transmitted to the server.

First, the mobile station 30 transmits data from the on-board communication terminal 33 to the i-th wireless base station connected wirelessly via the wireless device 32 and the antenna 31 (S
21). The i-th wireless base station that has received the data relays the data to the first wireless device according to the flow shown in FIG. 2, thereby transmitting the data to the adjacent (i-1) -th wireless base station (S22). . Similarly, data is relayed from the (i-1) th wireless base station to the hth wireless base station according to the flowchart shown in FIG. 2 (S23, S24). The h-th wireless base station that has received the data from the (h−1) th relays the data to the first upper station 10 according to the flowchart of FIG. 3 (S25), and the first upper station 10 receives the data (step S25). S
26).

FIG. 5 is a block diagram of the first upper station 10 to the mobile station 30.
5 is a flowchart when data is transmitted to the server.

First, the first upper station 10 is connected to the h-th station.
The data is transmitted to the wireless base station (S31). The h-th wireless base station having received the data relays the data to the first wireless device, the second wireless device, and the third wireless device according to the flow shown in FIG. And the (h + 1) th wireless base station transmits data to the mobile station 30 (S3).
2). However, since the mobile device 30 is not connected to the h-th wireless base station, it does not receive data. The (h-1) th wireless base station and the (h + 1) th wireless base station that have received data from the hth wireless base station transmit data to another adjacent wireless base station according to the flow shown in FIG. Transmits data to the mobile device 30 (S33, S33).
34). However, since the mobile device 30 is not connected to the h-th wireless base station, it does not receive data. Similarly, data relay processing is performed in each wireless base station according to the flowchart of FIG. 2 (S35 to S40). Also, the i-th
When the data is transmitted from the wireless base station to the mobile station 30 (S38), the mobile station 30 receives the data (S4).
1).

FIG. 6 is a block diagram of one embodiment of the wireless communication system according to the ninth aspect of the present invention.

In FIG. 6, in a radio zone composed of k (2 ≦ k ≦ L) radio base stations, the frequency channels usable for communication between the radio base station and the mobile station are N to fN.
7 shows an example of a frequency channel assignment method when a channel exists.

In FIG. 6, a wireless zone composed of a first radio base station to a k-th radio base station is defined as a first radio zone, and a radio zone composed of a (k + 1) th radio base station to a 2k-th radio base station. A wireless zone defined by a second wireless zone is similarly defined as a second wireless zone, and a wireless zone including the k (N−1) +1 wireless base stations to the kNth wireless base station is similarly configured from the Nth wireless zone.

The ninth aspect of the present invention is a system in which the frequency channels used by a plurality of radio base stations are the same in the configuration of the radio zone shown in FIG. In one example, f1 is used in the first wireless zone, f2 in the second wireless zone,..., FN in the Nth wireless zone. Further, frequency channels from f1 to fN may be repeatedly used so that f1 is used in the (N + 1) th wireless zone. However, in order to prevent interference between wireless zones, it is desirable to assign different frequency channels to adjacent wireless zones when assigning frequency channels.

In a radio zone which is subject to interference from another radio communication system, the radio base station measures the radio wave level from the other radio communication system on all frequency channels,
This is a method of selecting and using a frequency channel that is less affected by interference.

FIG. 7 shows that the data relay function mounted on the radio base station uses TCP / IP (Transmission Control Protocol / Inte
6 is a flowchart of a filtering process when performing communication using the Rnet Protocol.

In TCP / IP communication, generally, reception in an IP header is performed.
Communication can be uniquely identified by the four identification information of the IP address and the transmission IP address, the reception port and the transmission port in the TCP header. In addition to these four identification information, TC
The data can be uniquely identified by referring to the sequence number included in the P header. Therefore, in the communication terminal 33, the reception IP address of the received data,
The filtering process is performed by referring to five pieces of identification information such as an IP address, a reception port, a transmission port, and a sequence number. S51: The identification information of the received data is obtained by referring to the IP header and the TCP header from the received data. S52: Inquire whether the identification information of the received data matches the already recorded identification information. S53: If all the five pieces of identification information match in S52, it is determined that the received data is the same as the previously received data, and the data is discarded. S54: If at least one of the five pieces of identification information does not match, five pieces of identification information are recorded.

However, a time stamp may be added when recording the five pieces of identification information, and the recording of the identification information may be discarded after a certain period of time.

Further, one embodiment of the invention according to claim 7 is that the filtering processing shown in FIG. 7 is provided in the connection function mounted on the k-th higher station (1 ≦ k ≦ M). .

FIG. 8A is a block diagram of one embodiment of the radio communication system according to the fourth aspect of the present invention. FIG.
FIG. 8B is a configuration diagram of the wireless base station of FIG. 8A.

In FIG. 8A, L radio base stations arranged in tandem along the radio service area and the h th radio base station (1 ≦ h ≦ L) are connected by wire or radio, and higher-level communication is performed. First higher-level station (h) enabling connection to a line
12, a first higher-level station (j) 14 connected to a j-th wireless base station (1 ≦ j ≦ L) by wire or wireless to enable connection to a higher-level communication line, and an i-th wireless base station The mobile station 30 is connected to a base station (1 ≦ i ≦ L) wirelessly and receives a communication service.

In the present embodiment, the first
It is assumed that there are two upper stations, but the same method can be applied to the case where there are three or more first upper stations.

FIG. 9 shows an embodiment according to claim 4.
The k-th wireless base station that is not connected to the first upper station (1 ≦ k
5 is a flowchart of a data relay function provided in ≦ L). S61: Determine the wireless device to which the data has been input. S62: If it is determined in S61 that the data is input from the first wireless device, the input data is relayed to the second wireless device and the third wireless device. S63: If it is determined in S61 that the data is input from the second wireless device, the input data is relayed to the first wireless device and the third wireless device. S64: If it is determined in S61 that the data is input from the third wireless device, the input data is relayed to the first wireless device and the second wireless device.

FIG. 10 is a flowchart when data is transmitted from the mobile station 30 according to the fourth aspect of the present invention.

First, the mobile station 30 transmits data from the on-board communication terminal 33 to the i-th wireless base station connected wirelessly through the wireless device 32 and the antenna 31 (S
71). In the i-th wireless base station receiving the data, FIG.
According to the flowchart shown in (1), the data is transmitted to the adjacent wireless base station by relaying the data to the first wireless device and the third wireless device (S72). Similarly, when relaying is performed between the wireless base stations and the h-th wireless base station and the j-th wireless base station receive data, the first higher-order station (h ) 12 and the data are relayed to the first upper station (j) 14 (S7).
3, the first upper station (h) 12 and the first upper station (j) 14 receive the data (S75, S7).
6).

FIG. 11 is a block diagram of an embodiment in which the third higher-order station is the highest-order station in the radio communication system according to the sixth aspect of the present invention. In FIG. 11, the plurality of upper stations are configured in a hierarchical structure, and the second upper station is connected to the plurality of first upper stations by wire or wirelessly, and is connected to the plurality of second upper stations by wire or wireless. Is a wireless communication system including a third higher-order station as a component. Also, the k-th
(1 ≦ k ≦ 3) relays the data addressed to the mobile station to the (k−1) th upper station as the lower station, and transmits the data transmitted from the mobile station to the (k + 1) th upper station as the upper station. It has a connection function for relaying to a PC. However, since the lower station of the first upper station is a connected radio base station and there is no upper station of the third upper station, data is terminated at the third upper station.

In the present embodiment, it is assumed that the third upper station is the highest station in the radio communication system. However, even when the Mth higher station (M ≧ 2) is the highest station, It can be applied in a similar way.

FIG. 12 is a flowchart when data is transmitted from the upper station to the mobile station 30 according to the sixth aspect of the present invention. The present embodiment is an example of a case where data is relayed to a plurality of first upper stations when the second upper station transmits data to the mobile station 30.

First, when transmitting data to the mobile station, the third upper station relays the data to the second upper station (1) (S8).
1). The second upper station (1) that has received data from the third upper station relays the data to the connected first upper station (S82). The plurality of first upper stations that have received the data from the second upper station (1) relay the data to the respectively connected wireless base stations (S83, S84, S85). Also, regarding the communication between the first upper station and the mobile station, FIG.
The data transmitted from the second upper-level station is finally received by the mobile station 30.

However, when the k-th upper station (2 ≦ k ≦ M) transmits data to the (k−1) -th upper station, which is the lower station, the k-th upper station performs transmission based on the position information of the mobile station. -1
May be determined.

According to the various embodiments of the present invention described above, various changes, modifications, and omissions of the technical idea and scope of the present invention can be easily made by those skilled in the art. The foregoing description is merely an example, and is not intended to be limiting. The invention is limited only as defined by the following claims and equivalents thereof.

[0054]

As described above in detail, according to the present invention, in a wireless communication system in which service areas such as expressways are developed in tandem, wireless base stations are arranged in tandem along the service area. However, by connecting the adjacent wireless base stations wirelessly, the wireless base stations directly connected to the upper station can be limited, and the cost for constructing the communication infrastructure can be reduced.

In a radio zone composed of a plurality of radio base stations, a plurality of radio base stations use the same radio frequency channel, so that when a mobile station moves between radio base stations, the radio frequency of the mobile station is reduced. The switching process of the frequency channel becomes unnecessary. Therefore, the wireless devices of the mobile station and the wireless base station can have a simple configuration. In a wireless zone that receives interference from another wireless system, deterioration of communication quality can be prevented by using a frequency channel that is less affected by the interference.

By constructing the upper stations hierarchically, a large-scale system can be constructed. Specifically, a wireless communication system accommodating a plurality of highways can be constructed, and a wide range of information services can be provided.

When adjacent radio base stations use the same frequency, the same duplicate data can be transmitted to an upper station by receiving data transmitted from a mobile station by a plurality of radio base stations. There is. Conversely, the mobile station may receive the same data redundantly from a plurality of radio base stations. It is conceivable that the occurrence of such duplicate data causes a malfunction in the communication protocol. Therefore, by performing the filtering process on the same data, it is possible to prevent a malfunction in the communication protocol. Further, by discarding the duplicate data by the filtering process, the communication band can be effectively used. Specifically, it is possible to effectively use the communication band between the adjacent radio base stations by performing the filtering process in the radio base station, and to effectively use the higher communication line by performing the filtering process in the higher station. Become.

When there are a plurality of first upper stations in the radio communication system, the radio base station receiving the data transmitted from the mobile station relays the received data to the plurality of first upper stations. Even if a failure occurs in a device and a communication path on one of the relay paths, communication can be continued. Therefore, the reliability of the entire wireless communication system can be improved. In addition, the higher station relays data to a plurality of lower stations, so that the same effect can be obtained for data transmitted to the mobile station.

[Brief description of the drawings]

FIG. 1a is a configuration diagram of an embodiment of a wireless communication system according to the present invention.

FIG. 1b is a configuration diagram of a radio base station according to the present invention.

FIG. 2 is a flowchart of a data relay function provided in a wireless base station that is not connected to the first upper station 10.

FIG. 3 is a flowchart of a data relay function provided in a wireless base station connected to a first upper station 10.

FIG. 4 is a flowchart when data is transmitted from the mobile station 30 to the first upper station 10.

FIG. 5 is a flowchart when data is transmitted from the first upper station 10 to the mobile station 30.

FIG. 6 is a configuration diagram of an embodiment of a wireless communication system according to the invention of claim 9;

FIG. 7 is an example of a flowchart of a filtering process as one embodiment of the wireless communication system according to the fifth or seventh aspect of the present invention.

FIG. 8a is a configuration diagram of an embodiment of a wireless communication system according to the invention of claim 4.

8B is a configuration diagram of the wireless base station of FIG. 8A.

FIG. 9 is a flowchart of a data relay function provided in a wireless base station that is not connected to a first higher-level station in the invention described in claim 4;

FIG. 10 is a block diagram showing a mobile station 30 according to the fourth embodiment;
6 is a flow chart when data is transmitted from a.

FIG. 11 is a configuration diagram of an embodiment in a case where the third higher-order station is the highest-order station in the wireless communication system according to the sixth aspect of the present invention.

FIG. 12 is a flowchart when data is transmitted from the upper station to the mobile station 30 in the invention according to claim 6;

[Explanation of symbols]

 Reference Signs List 10 first upper station 11 connection function 12 first upper station (h) 13 connection function 14 first upper station (j) 15 connection function 20 wireless base station connected to first upper station 21 data relay function 22 wireless base station not connected to first upper station 23 data relay function 30 mobile station 31 antenna 32 wireless device 33 communication terminal

Continuing from the front page (72) Inventor Tadayuki Fukuhara 2-1-1-15 Ohara, Kamifukuoka-shi, Saitama Pref. Inside Kaididi Laboratory Co., Ltd. (72) Naoki Fukuya 2-1-1-15 Ohara, Kamifukuoka-shi, Saitama Kaididi Co., Ltd. Inside the research institute (72) Keizo Sugiyama 2-1-1-15 Ohara, Kamifukuoka-shi, Saitama Pref.Kididi Research Institute Co., Ltd. F term (reference) 5K067 AA41 BB21 DD17 EE02 EE06 EE10 EE16 EE44 HH23 HH24 KK03

Claims (9)

[Claims] A plurality of radio base stations are arranged in cascade to cover radio zones arranged in cascade, and the radio base stations are configured to communicate with both adjacent radio base stations by a first radio base station. And a second antenna, and a third antenna for wirelessly communicating with the mobile station, wherein the data received by the radio base station is relayed and transmitted via an adjacent radio base station. Road wireless communication system characterized by the above-mentioned. 2. A mobile station, comprising: a first higher-level station connected by wire or wireless to one of a plurality of radio base stations arranged in the cascade; The data transmission between the 1 upper station is
2. The mobile station according to claim 1, wherein the data is relay-transmitted via a plurality of radio base stations existing between the first radio base station and a second radio base station communicating with the mobile station by radio. The road wireless communication system according to claim 1. 3. The radio base station, when the first antenna is an antenna that relays and transmits to the first upper station, the data received by the first antenna is the second and the second data. Transmitting data to the third antenna, transmitting data received by the second antenna to the first antenna, and transmitting data received by the third antenna to the first antenna. The road radio communication system according to claim 2, wherein 4. The first antenna, wherein there are a plurality of the first upper stations, and the first antenna and the second antenna are each an antenna for relay transmission to the first upper station. Is transmitted to the second and third antennas, data received by the second antenna is transmitted to the first and third antennas, and received by the third antenna The road wireless communication system according to claim 2, wherein the data is transmitted to the first and second antennas. 5. The wireless base station records identification information of relayed data, and when receiving data of the same identification information a plurality of times, discards the data received the second and subsequent times. The road wireless communication system according to claim 1. 6. A further higher-order second higher-order station connected to the plurality of first higher-order stations by wire or wirelessly,
The M-th upper station (M ≧ 2) is connected to the plurality of M-th higher stations (M ≧ 2) by wire or wirelessly, and the M-th upper station has a hierarchical structure. Items 2 to 5
The road wireless communication system according to any one of claims 1 to 4. 7. The high-order station records identification information of relayed data, and when receiving data of the same identification information a plurality of times, discards the data received from the second time on. Item 7. A road wireless communication system according to item 6. 8. The k-th upper station (2 ≦ k ≦ M) transmits data to a plurality of (k−1) -th upper stations when transmitting data to the mobile station. Item 8. The road wireless communication system according to item 6 or 7. 9. The road radio communication according to claim 1, wherein one radio zone of the same radio frequency channel is covered by a plurality of radio base stations by a carrier detection method. system.