Mobile radio communication system

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a mobile radio communication system, for example, to a train radio communication system.

【0002】

[Conventional technology]

FIG. 2 shows a configuration example of a train radio communication system as an example of the prior art. In Fig. 2, 1 and 1'are the radio base stations that transmit the same content, 2 and 2'are the leaky coaxial cables on the right side of the moving direction, and 3 is the boundary point between the leaky coaxial cables 2 and 2'. Leaked radio interference section that occurs, 4 and 4'are the leaked coaxial cable on the left side of the moving object traveling direction, 5 is the leaked coaxial cable that occurs at the boundary between 4 and 4', 6 is the front right side of the moving body. Antenna installed in, 7 is an antenna installed on the front left side of the moving body, 8 is a wireless mobile station equipped with a radio, 9 is an antenna installed on the rear right side of the moving body, 10 is on the rear left side of the moving body It is an antenna to be installed. The operation by the conventional technique is shown below. The signals transmitted from the radio base stations 1 and 1'are transmitted as leaked coaxial cables via the leaky coaxial cables 2, 2'and 4, 4', and are transmitted as leaked radio waves from the leaked coaxial cables 2 and 2'. Signals are mainly received by antennas 6 and 9, and signals transmitted as leaked coaxial cables from 4 and 4'are mainly received by antennas 7 and 10. At this time, the leaked radio waves from the leaked coaxial cables 2 and 2'can hardly be received by the antennas 7 and 10 on the opposite side because the mobile radio station 8 itself acts as a shield. When the mobile radio station 8 is in the position shown in FIG. 2, the front antennas 6 and 7 are both within the range of the leaked radio wave interference sections 3 and 5, and the leaked radio wave cannot be received normally. On the other hand, the rear antennas 9 and 10 are in a positional relationship that does not affect the leaked radio wave interference sections 3 and 5, and the leaked coaxial cable 2' And the leaked radio wave from 4 can be received normally. When the mobile radio station 8 moves forward and the antennas 9 and 10 behind the mobile radio station enter the sections of the leaked radio wave interference sections 3 and 5, the antennas 6 and 7 in front of the radio mobile station 8 enter the leaked radio wave interference sections 3 and 5. It goes out of range and can normally receive the leaked radio waves from the leaked coaxial cables 2 and 4. In this way, the leaked radio waves from the leaked coaxial cables on both the left and right sides of the mobile radio station 8 are received by the antennas before and after the mobile radio station 8, respectively, and by configuring the diversity, stable communication is performed even at the boundary of each radio base station area. It can be secured, but there are the following problems. First, even if the leaky coaxial cable is used, the leaked coaxial from the leaked coaxial cable in the adjacent radio base station area interferes with each other at the boundary point with the leaked coaxial cable. It is necessary to keep the distance between the antennas in front of and behind the moving body at least the same distance as the section where the level of the leaked radio wave from the cable is the same. This depends on the frequency band used by the radio, but in the 400MHz band, for example, at least 10m or more is required due to the gain attenuation characteristics of the leaky coaxial cable. For this reason, a dead zone section will be created on the system for a moving object of 10 m or less. Secondly, if only the antennas in front of and behind the moving body are lined up next to each other, they will be blocked and communication will not be possible. For this reason, antennas are required in the left-right direction of the moving body, and a total of four antennas are required in front, back, left, and right. You have to keep a distance. This depends on the frequency band used by the radio, but in the 400MHz band, for example, at least 10m or more is required due to the gain attenuation characteristics of the leaky coaxial cable. For this reason, a dead zone section will be created on the system for a moving object of 10 m or less. Second, if only the antennas in front of and behind the moving body are lined up next to each other, they will be blocked and communication will not be possible. For this reason, antennas are required in the left-right direction of the moving body, and a total of four antennas are required in front, back, left, and right. You have to keep a distance. This depends on the frequency band used by the radio, but in the 400MHz band, for example, at least 10m or more is required due to the gain attenuation characteristics of the leaky coaxial cable. For this reason, a dead zone section will be created on the system for a moving object of 10 m or less. Secondly, if only the antennas in front of and behind the moving body are lined up next to each other, they will be blocked and communication will not be possible. For this reason, antennas are required in the left-right direction of the moving body, and a total of four antennas are required in front, back, left, and right.

【0003】

[Problems to be Solved by the Invention]

In the above-mentioned conventional technique, it is necessary to arrange the antennas at a sufficient distance in the front-rear direction of the moving body, and further, it is necessary to install the antennas on the left and right sides in order to prevent communication interruption due to shielding of the adjacent moving body. An object of the present invention is to eliminate the above drawbacks and to provide a mobile wireless communication system without interruption of communication.

【0004】

[Means for solving problems]

In order to achieve the above object, the present invention is laid by shifting the section position, which is the boundary between the radio areas of the leaky coaxial cable laid on the left and right of the mobile line, to the left and right, thereby causing leakage radio interference between the radio areas. When the moving body passes through the section where communication is not possible due to, either of the antennas installed on the left and right sides of the moving body must be in a communicable area, and there is no need to install a combination antenna in the front-back direction of the moving body. Only the combination antenna of the above is installed to prevent the communication from being interrupted.

【0005】

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described with reference to FIG. In Fig. 1, 1 and 1'are the radio base stations that transmit the same content, 2 and 2'are the leaky coaxial cables on the right side of the moving direction, and 3 is the boundary point between the leaky coaxial cables 2 and 2'. Leaked radio interference section that occurs, 4 and 4'are the leaked coaxial cable on the left side with respect to the moving direction, 5 is the leaked coaxial cable that occurs at the boundary between 4 and 4', 6 is the front right side of the moving body. 7 is an antenna installed on the front left side of the mobile body, and 8 is a wireless mobile station equipped with a radio. The operation will be described below with reference to FIG. The signals transmitted from the radio base stations 1 and 1'are transmitted as leaked coaxial cables via the leaky coaxial cables 2, 2'and 4, 4', and are transmitted as leaked radio waves from the leaked coaxial cables 2 and 2'. The signal transmitted from the leaky coaxial cable of 4 and 4'is mainly received by the antenna 6, and the signal transmitted as the leaked radio wave is mainly received by the antenna 7. The leaky coaxial cable is laid at a position where the boundary point between the leaky coaxial cables 2 and 2'and the leakage radio wave interference sections 3 and 5 generated at the boundary point between 4 and 4'are predetermined distances from each other. This separation distance depends on the frequency band used, but for example, in the 400 MHz band, as described above, in the case of 10 m and in the 150 MHz band, there is almost no problem if the distance is 200 m from the gain attenuation characteristic of the leaky coaxial cable. The same effect can be obtained by separating the antenna in the front-rear direction on the wireless mobile station 8 side for the distance, but in the case of the 400 MHz band on the mobile body side, it is practically difficult to separate the distance as much as 200 m. Further, the separation effect can be further obtained by arranging the left and right antennas on the wireless mobile station 8 side in the front-rear direction. When the radio mobile station 8 is in the position shown in FIG. 1, the antenna 6 is in the leaked radio wave interference section 3 and cannot normally receive the leaked radio wave. At this time, since the antenna 7 is in a position that does not affect the leaked radio wave interference section 5, the leaked coaxial cable 4' Can receive the leaked radio waves from. When the mobile radio station 8 advances and the antenna 7 enters the section of the leaked radio wave interference section 5, the antenna 6 escapes from the leaked radio wave interference section 3 and can normally receive the leaked radio wave from the leaked coaxial cable 2. By intentionally shifting the leaked radio wave interference section to the left and right of the line or the like in this way, it is possible to prevent a momentary interruption of communication at the area boundary. In this case, the number of antennas installed in the mobile radio station 8 may be two on the left and right, and the antenna switching control of the radio can be simplified as compared with the case of four antennas. Moreover, even if it passes by another mobile radio station in a normal section, communication can be performed without any problem.

【0006】

[Effect of the invention]

According to the present invention, it is possible to provide a mobile wireless communication system that continues communication without interruption even when a wireless mobile station passes near a wireless area boundary.

[Simple explanation of drawings]

[Figure 1]

Configuration diagram of an embodiment according to the present invention [Figure 2]

Configuration diagram of an example according to the prior art [Explanation of symbols]

1: Radio base station, 2: Right leaked coaxial cable, 3: Right leaked radio interference section, 4: Left leaked coaxial cable, 5: Left leaked radio interference section, 6: Radio mobile station right front antenna, 7: Radio mobile station Left front antenna, 8: wireless mobile station, 9: wireless mobile station right rear antenna, 10: wireless mobile station left rear antenna