JPH11186943A - Radio relay system using conventional coaxial cable with leakage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio relay system using conventional coaxial cables with leakage that economically copes with a new mobile communication service with difference frequencies by effectively utilizing leakage coaxial cables or the like, having already been installed in a closed space. SOLUTION: A frequency converter 23-3 in a repeater 23 converts a radio wave from a base station 22 into a frequency corresponding to a leakage coaxial cable 25 and the frequency-converted radio wave is sent to the leakage coaxial cable 25. The radio wave from the leakage coaxial cable 25 in a tunnel 24 is converted again into a transmission frequency of the base station 22, and the re-converted radio wave is emitted to a mobile station 41 in the tunnel 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an existing leaky coaxial cable for relaying a radio wave from a base station and a radio wave from a mobile station to enable radio communication in a closed space including an underground mall and a tunnel in a mobile communication system. More specifically, a radio relay system using a wireless communication system transmits radio waves from a base station to a leaky coaxial cable installed in a closed space including an underground mall and a tunnel in a mobile communication system. A radio relay system using an existing leaky coaxial cable that radiates radio waves to mobile stations and receives radio waves from mobile stations in a closed space with the leaky coaxial cable and transmits the radio waves to the base station via the leaky coaxial cable. About.

[0002]

2. Description of the Related Art A conventional radio relay system using a leaky coaxial cable of this type will be described with reference to FIGS. In FIG. 2, 1 is a base station, 3 is a base station antenna, 2-1 and 2-2 are amplifiers in the relay device 2,
3, 2-4 are duplexers, 4 is a leaky coaxial cable laid in a tunnel 7, 5 is an intermediate repeater, and 6 is a mobile station.

A downstream radio wave from the base station 1 is received by the base station antenna 3, passed through the duplexer 2-4, amplified by the amplifier 2-1 and passed through the duplexer 2-3, and then leaked coaxially. The signal is transmitted to the cable 4 (where the transmission attenuation of the leaky coaxial cable falls below a required value, amplified by the intermediate repeater 5 as attenuation compensation), and radiated from the leaky coaxial cable 4 to the mobile station 6. The upstream radio wave from the mobile station 6 is received and transmitted by the leaky coaxial cable 4, passes through the duplexer 2-3 in the repeater 2, is amplified by the amplifier 2-2, and is transmitted through the duplexer 2-4. After passing through, it is radiated from the base station antenna 3 to the base station 1.

FIG. 3 shows a configuration in which the base station 1 and the relay device 2 are directly connected, and there is no need to fly the space between the base station 1 and the relay device 2 by radio waves as shown in FIG. It has the same configuration as FIG. 2 except that it does not require a base station antenna and a duplexer.

FIGS. 4 and 5 show an example of a conventional radio relay system using an optical cable and an antenna in a blind spot. In FIG. 4, 1 is a base station, 4 is a base station antenna, 3-
1 and 3-2 are amplifiers in the relay device 2, and 15 is an electric /
An optical converter, 16 is an optical / electrical converter, 8 is an optical fiber transmission line for the wireless relay terminal device 12 disposed in the tunnel 7, and 10 in the wireless relay terminal device 12 is an optical signal transmitted by an optical fiber. Is an optical / electrical converter for converting the optical signal into an electric signal, and 14 is an electric / optical converter.

A downstream radio wave from the base station 1 is received by the base station antenna 4, amplified by the amplifier 3-1, converted into an optical signal by the electric / optical converter 15, and tunneled by the optical fiber transmission line 8. After being converted into an electric signal again by the optical / electrical converter 10 in the internal wireless relay terminal device 12, the electric signal is radiated to the mobile station 13 from the mobile station antenna 9. Uplink radio waves from the mobile station are received by the mobile station antenna 9 connected to the wireless relay terminal device 12, converted into an optical signal by the electric / optical converter 14, and transmitted to the relay device 2 through the optical fiber transmission line 8. Then, the signal is converted into an electric signal by the optical / electrical converter 16 in the repeater, amplified by the amplifier 3-2, and radiated from the base station antenna 4 to the base station 1.

FIG. 5 shows a configuration in which the base station 1 and the relay device 2 are directly connected. Since there is no need to fly the space between the base station 1 and the relay device 2 by radio waves as shown in FIG.
It has the same configuration as FIG. 4 except that it does not require a base station antenna and an amplifier.

The frequency at which transmission and reception can be performed is determined for each type of leaky coaxial cable and antenna. Therefore, in such a system, when a mobile communication service using another frequency other than the frequency corresponding to the leaky coaxial cable or antenna is performed in the tunnel, (1)
There is a method of newly installing a system corresponding to the frequency, or (2) renewing the equipment to a frequency corresponding to a new service frequency. When there is no space for installing new equipment such as a railway tunnel where the installation position is narrow (2)
I have to take the method of.

However, in order to do so, it is natural to change the apparatus in order to cope with the frequencies of the amplifiers of the repeater and the intermediate repeater, but it is also possible to newly cope with the frequency by removing the leaky coaxial cable. It is necessary to lay a leaky coaxial cable again. The same applies to the case where an antenna is used. It is necessary to replace the antenna capable of newly supporting the frequency and, if necessary, replace the wireless relay terminal device and re-install the optical fiber.

Further, regarding the installation position of the intermediate repeater, the newly laid leaky coaxial cable may have transmission characteristics and transmission / reception characteristics different from those in the case of transmission in the previous frequency band. Redesign of the installation position is required. Similarly, even in the case of the antenna system, it is necessary to redesign the radio relay terminal device and the antenna installation position due to a difference in radio wave propagation characteristics depending on the frequency of a new mobile communication service to be performed, and particularly in a tunnel. Therefore, there has been a situation where the system cannot be easily introduced in such a tunnel or the like.

[0011]

In the above-described conventional wireless relay system, when a mobile communication service having a different frequency is newly provided to a wireless relay system already installed in a blind area, the wireless relay system newly supports the frequency. However, there is a problem that a system adapted to all the frequency bands in which services are to be provided must be installed or the system must be newly renewed.

The present invention has been made in view of the above,
The aim is to use existing leaky coaxial cables that can be used economically for new mobile communication services with different frequencies by effectively using leaky coaxial cables already installed in a closed space. Is to provide.

[0013]

To achieve the above object, the present invention according to claim 1 provides a mobile communication system in which a leaky coaxial cable installed in a closed space including an underground mall and a tunnel is connected to a base station by a leaky coaxial cable. Transmitting the radio wave, radiating the radio wave from the leaky coaxial cable to the mobile station in the closed space, receiving the radio wave from the mobile station in the closed space with the leaky coaxial cable, and transmitting the radio wave from the leaky coaxial cable to the base station. A radio relay system using an existing leaky coaxial cable for transmitting the radio wave from a base station (specifically, a base station using a different frequency newly installed) to a frequency corresponding to the leaky coaxial cable. A first frequency converting means for transmitting the frequency-converted radio wave to the leaky coaxial cable; and a radio wave from the leaky coaxial cable in the closed space. Then reconverted to installed the transmission frequency of the base station, and summarized in that a second frequency converting means for radiating the reconverted electric wave to the mobile station in the closed space.

According to the first aspect of the present invention, for example, a radio wave from a newly installed base station is converted into a frequency corresponding to a leaky coaxial cable by a first frequency conversion means, and the frequency-converted radio wave is converted. The signal is transmitted to the leaky coaxial cable, the radio wave from the leaky coaxial cable is converted back to the transmission frequency of the base station in the closed space, and the reconverted radio wave is radiated to mobile stations in the closed space. Coaxial cables can be used to address new mobile communication services with different frequencies.

[0015] The present invention described in claim 2 provides the present invention in claim 1.
In the invention described in the above, a radio wave from a mobile station is received in the closed space, the received radio wave is frequency-converted to a corresponding frequency of the leaky coaxial cable, and the frequency-converted radio wave is transmitted to the leaky coaxial cable. The gist of the present invention is to include frequency conversion means of No. 3 and fourth frequency conversion means for converting radio waves from the leaky coaxial cable into the frequency of a base station and transmitting the frequency-converted radio waves to the base station.

According to the second aspect of the present invention, the radio wave from the mobile station is converted into the frequency corresponding to the leaky coaxial cable by the third frequency conversion means in the closed space, and the converted radio wave is converted into the leaky coaxial cable. And the radio wave from the leaky coaxial cable is converted to the frequency of the base station by the fourth frequency conversion means,
In order to transmit the converted radio wave to the base station, it is possible to cope with a new mobile communication service having a different frequency using an existing leaky coaxial cable.

Further, the present invention according to claim 3 provides the invention according to claim 1.
Alternatively, in the invention described in Item 2, an antenna is used instead of the leaky coaxial cable.

According to the third aspect of the present invention, a new mobile communication service having a different frequency can be handled by using an existing antenna.

[0019]

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

FIG. 1 is a diagram showing a configuration of a wireless relay system using an existing leaky coaxial cable according to an embodiment of the present invention. In this embodiment, a case where a leaky coaxial cable is used will be described. However, the present embodiment can be applied to a case where an antenna is used instead of a leaky coaxial cable. Further, in the present embodiment, the case where the existing leaky coaxial cable and the relay device are directly connected will be described. However, the same applies to the case where the connection is performed by radio waves as in FIGS. 2 and 4 described above.

In FIG. 1, reference numeral 21 denotes an existing railway radio base station, 22 denotes a mobile communication base station that newly provides service,
23 is a relay device, 23-1, 23-5, 23-7, 23
-10 is an amplifier, 23-2 and 23-8 are distributors, 23-
4, 23-9 is a synthesizer, 23-3 is a frequency converter, 23
-6 is a duplexer. 25 is an existing leaky coaxial cable in the tunnel 24, 26 is an existing repeater, 27 is a frequency converter installed in the train 71, 29 and 40 are antennas, and 41 is a mobile station in the train.

In FIG. 1, several channels of downstream radio waves from the base station 22 are amplified by the amplifier 23-1 in the repeater 23, and the frequency converters 2 for the number of channels are distributed by the distributor 23-2.
It is distributed for input to 3-3, and is converted to the frequency of the existing railway radio frequency band in each frequency converter. Output signals from the respective frequency converters are combined by a combiner 23-4, amplified by an amplifier 23-5, and passed through a duplexer 23-6.
Is combined with a signal from the existing railway radio base station 21 and connected.

The mobile communication radio wave radiated from the leaky coaxial cable 25 in the tunnel 24 is received by the antenna 29 connected to the frequency conversion device 27 installed in the train 71, and is transmitted by the frequency conversion device 27 to the mobile communication base station. The signal frequency is again converted to the signal frequency from the antenna 22, radiated from the antenna 40 and received by the mobile station 41.

The upstream signal from the mobile station 41 is transmitted to the antenna 4
0, is converted to a frequency in the existing railway radio frequency band by the frequency conversion device 27, radiated from the antenna 29, received by the existing leaky coaxial cable 25, and transmitted to the relay device 23. In the relay device 23, the duplexer 2
After passing through 3-6, the signal is amplified by the amplifier 23-7,
It is distributed by 3-8 and input to the frequency converter 23-3. The frequency converter 23-3 converts the frequency into the frequency received by the mobile communication base station 22, outputs the converted frequency, synthesizes the synthesized frequency with the synthesizer 23-9, amplifies the amplified frequency with the amplifier 23-10, and transmits the amplified frequency to the mobile communication base station 22. .

[0025]

As described above, according to the present invention,
The radio wave from the base station is converted to the corresponding frequency of the leaky coaxial cable by the first frequency conversion means, the frequency-converted radio wave is transmitted to the leaky coaxial cable, and the radio wave from the leaky coaxial cable is transmitted to the base station in the closed space. In order to re-convert to the transmission frequency and radiate the re-converted radio waves to mobile stations in a closed space, the existing leaky coaxial cable is used, and a new mobile with a different frequency including a mobile phone or a radio call is used. Can deal with communication services economically.

According to the present invention, the radio wave from the mobile station is converted into the frequency corresponding to the leaky coaxial cable by the third frequency conversion means in the closed space, and the converted radio wave is transmitted to the leaky coaxial cable. An electric wave from the leaky coaxial cable is converted to the frequency of the base station by the fourth frequency conversion means, and the converted electric wave is transmitted to the base station. It is possible to economically cope with a new mobile communication service having a different frequency, including:

Further, according to the present invention, a new mobile communication service having a different frequency can be handled by using an existing antenna.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a wireless relay system using an existing leaky coaxial cable according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a conventional wireless relay system using a leaky coaxial cable.

FIG. 3 is a diagram showing a configuration of a conventional wireless relay system using a leaky coaxial cable.

FIG. 4 is a diagram showing a configuration of a conventional wireless relay system using an optical cable and an antenna.

FIG. 5 is a diagram illustrating a configuration of a conventional wireless relay system using a leaky coaxial cable.

[Explanation of symbols]

 Reference Signs List 21 base station for railway radio 22 base station for mobile communication 23 repeater 23-3 frequency converter 24 tunnel 25 leaky coaxial cable 27 frequency converter 29, 40 antenna 41 mobile station

Claims (3)

[Claims] 1. A mobile communication system transmits radio waves from a base station to a leaky coaxial cable installed in a closed space including an underground mall and a tunnel, and radiates radio waves from the leaky coaxial cable to mobile stations in the closed space. And a radio relay system using an existing leaky coaxial cable for receiving radio waves from a mobile station in a closed space with the leaky coaxial cable and transmitting the radio wave to the base station via the leaky coaxial cable. First frequency conversion means for converting the radio wave of the leaked coaxial cable to a corresponding frequency of the leaky coaxial cable, and transmitting the frequency-converted radio wave to the leaky coaxial cable; and transmitting the radio wave from the leaky coaxial cable to the base station in a closed space. Second frequency conversion means for reconverting to a transmission frequency and radiating the reconverted radio waves to mobile stations in a closed space. Radio relay system using the existing leaky coaxial cable. 2. A method for receiving radio waves from a mobile station in the closed space, converting the received radio waves to a frequency corresponding to the leaky coaxial cable, and transmitting the frequency-converted radio waves to the leaky coaxial cable. And a fourth frequency converter for converting radio waves from the leaky coaxial cable into a base station frequency and transmitting the frequency-converted radio waves to the base station. Item 2. A wireless relay system using the existing leaky coaxial cable according to Item 1. 3. The wireless relay system using an existing leaky coaxial cable according to claim 1, wherein an antenna is used instead of the leaky coaxial cable.