KR20000019793A - Repetition apparatus for mobile communication service in inside of tunnel and installation method - Google Patents

Abstract

PURPOSE: A repetition apparatus for a mobile communication service in inside of the tunnel and an installation method are provided to provide a mobile communication service at the center of the inside of a tunnel long as a radio frequency signal cannot be transmitted. CONSTITUTION: A repetition apparatus for a mobile communication service in inside of the tunnel includes an exterior antenna(210, 310), a repeater(120, 160), a leakage coaxial cable140, 240, 340), and a tunnel antenna(250, 350). The exterior antenna is located outside of the tunnel entrance. The repeater is connected to the exterior antenna. A terminal part of the leakage coaxial cable is connected to the repeater through a feeder. The leakage coaxial cable is to transmit and receive a radio frequency signal in the inside of the tunnel. The tunnel antenna is connected to other terminal part of the leakage coaxial cable. The tunnel antenna is to transmit and receive a radio frequency signal in the inside of the tunnel.

Description

Relay device for mobile communication service in tunnel and its installation method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellular mobile telecommunication system. In particular, the present invention provides a mobile communication service by installing a leak coaxial cable (LCX) and an antenna in a tunnel with a long curved length. Repetition Apparatus and a method for installing the same.

The cellular mobile communication system divides the entire service area into a plurality of base station areas and constitutes cells, which are small service areas, and centrally controls these base stations to the mobile switching center so that subscribers can continue to talk while moving between cells. Make sure In cellular systems, a handoff function allows a call to continue when the mobile phone leaves a cell of a base station and enters a new cell.

1 is a block diagram of a typical cellular mobile communication system. As shown, a mobile telephone 10, a base station 20 that provides a mobile communication service to a mobile telephone through a radio frequency (RF), and the base station is connected to another mobile switching center ( 40) or a mobile switching center 30 that connects to a Public Switched Telephone Network (PSTN) 50. When the mobile phone is located in a shadow area such as a tunnel area or behind a tall building, the mobile phone does not receive a mobile communication service because it cannot transmit and receive radio frequency signals with a base station. The relay device amplifies radio frequency signals from the base station or the mobile phone and then transfers the amplified signals to the mobile phone or the base station in order to provide a mobile communication service in the shaded area.

U.S. Patent No. 5,659,879, "Method of covering shadow areas in a cellular mobile radio system and radio booster for implementing this method," provides a mobile communication service in a shaded area by installing a booster where radio waves cannot reach. A method is disclosed. The amplifier receives the radio frequency signal and then sends it back to the shaded area through the antenna.

However, since the radio frequency signal transmitted through the antenna does not reach the inside of the long and long tunnel area, it does not solve the shadow area in the tunnel. Therefore, another embodiment of the relay device according to the prior art uses a leaky coaxial cable (LCX). 2 is a configuration diagram of a relay apparatus using a leaky coaxial cable according to the prior art, and as shown, a first antenna for transmitting and receiving a radio frequency signal to and from a base station outside one inlet (point a) of the tunnel 100 ( 110, a first repeater 120 connected to the first antenna, a first feeder line 130 connected to the first repeater, a leaky coaxial cable located in the tunnel and connected to the first feeder line ( 140, a second feed line 170 connected to the leaky coaxial cable, a second relay 160 located outside the entrance (point d) of the tunnel and connected to the second feed line and an antenna connected to the second repeater ( 150).

The leakage coaxial cable 140 transmits the radio frequency signal received by the antenna 110 or the antenna 150 to the mobile phone in the tunnel, and transmits the signal from the mobile phone to the antenna 110 or the antenna 150. do. If the length of the tunnel is not long, the repeater is installed only at one entrance of the tunnel, and the end of the leaky coaxial cable which is not connected to the repeater is terminated. However, if the tunnel is long, repeaters are installed at both entrances (points a and d) of the tunnel, and the leaky coaxial cable is connected to both repeaters via feed lines.

When the strength of the radio frequency signal measured at point a is -75 dBm, the gain of the first antenna is 13 dB, the amplification gain of the first repeater is 90 dB, and the height of the leakage coaxial cable is 3 m. If the loss along the height is -60dB and the gain along the length of the leaky coaxial cable is -5dB every 100m, then the strength of the radio frequency signal received at the end of the 1Km long leaky coaxial cable is -82dBm. Since the threshold of the radio frequency signal power at which the mobile telephone can be serviced is usually set to -85 dBm, the service area by the first antenna and the first repeater is 1050 m. In addition, when the intensity of the radio frequency signal measured at the entrance b is -80 dBm, the gain of the second antenna is 13 dB, the amplification gain of the second repeater is 90 dB, and the loss according to the height of the leaky coaxial cable is -60 dB. If the gain along the length of the coaxial cable is -5 dB for every 100 m, the strength of the radio frequency signal received at the end of the 1 Km leaky coaxial cable is -87 dBm. If so, the service area by the second antenna and the second repeater is 1025m. As a result, the total service area is 2075m. However, if the tunnel is severely curved and the tunnel is very long (i.e. more than 2075 m), the mobile phone in the center of the tunnel cannot receive a sufficiently strong radio frequency signal over the leaky coaxial cable.

In other words, the conventional relay apparatus using a leaky coaxial cable could not provide mobile communication service in the center of the tunnel, which is severely curved and has a length of 2 km or more, so that the call of a mobile phone moving to the center of the tunnel is dropped. There was a problem.

SUMMARY OF THE INVENTION An object of the present invention, which was devised to solve the problems of the prior art operating as described above, is a mobile communication in a central portion of a tunnel inside the tunnel, which is long in length and long so that the leaky coaxial cable cannot transmit a radio frequency signal of sufficient strength. It is to provide a relay device for a mobile communication service in the tunnel area providing a service.

Another object of the present invention is the installation of a relay device for a mobile communication service in a tunnel area, which provides a mobile communication service in a tunnel long enough that the bent and leaky coaxial cable cannot transmit a radio frequency signal of sufficient strength. To provide a way.

Other objects and advantages of the present invention will become more apparent from the following detailed description of the invention and the accompanying drawings.

1 is a block diagram of a typical cellular mobile communication system.

2 is a configuration diagram of a relay apparatus using a leaky coaxial cable according to the prior art.

Figure 3 is a preferred embodiment of the relay device according to the present invention.

4 is an example of a tunnel to which the present invention is applied.

Figure 5 is a flow chart showing a preferred embodiment of the relay device installation method according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: mobile phone 20: base station

30,40: Mobile switching center 50: Public switched telephone network

100,200: tunnel 110,150: antenna

120,160: Repeater 130,170,230,330: Feeder

140,240,340: Leakage coaxial cable 210,310: External antenna

220,320 Repeater 250,350 Tunnel Antenna

In order to achieve the above object, a preferred embodiment of a relay apparatus for a mobile communication service in a tunnel according to the present invention, which provides a mobile communication service to a mobile telephone using a radio frequency, is provided. In a cellular mobile communication system comprising a base station,

An external antenna located outside the tunnel entrance;

A repeater connected to the external antenna;

A leakage coaxial cable having one end portion connected to the repeater through a feeder line and transmitting and receiving a radio frequency signal in a tunnel; And

It is connected to the other end of the leakage coaxial cable, and includes a tunnel antenna for transmitting and receiving radio frequency signals inside the tunnel.

A preferred embodiment of a method for installing a relay device for a mobile communication service in a tunnel according to the present invention includes a mobile phone and a base station for providing a mobile communication service to the mobile phone using a radio frequency. in,

Analyzing the internal environment of the tunnel;

Configuring an external antenna for transmitting and receiving radio frequency signals and a repeater connected to the external antenna, outside the tunnel entrance, according to the analysis result;

Installing a leaky coaxial cable along the tunnel;

Connecting a repeater to an inlet end of the installed leaky coaxial cable using a feed line; And

And connecting a tunnel antenna to an inner end portion of the tunnel of the installed leaky coaxial cable.

Another preferred embodiment of a method for installing a relay device for a mobile communication service in a tunnel according to the present invention is a cellular mobile communication including a mobile phone and a base station for providing a mobile communication service to the mobile phone using a radio frequency. In the system,

Analyzing the internal environment of the tunnel;

Installing an external antenna for transmitting and receiving radio frequency signals outside the tunnel entrance according to the analysis result;

Connecting a repeater to the external antenna;

Connecting a leaky coaxial cable to the repeater using a feed line; And

Connecting a tunnel antenna to the leak coaxial cable.

In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification. Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle and effects of the preferred embodiment of the present invention.

The relay apparatus according to the present invention combines a leaky coaxial cable and a tunnel antenna to provide a mobile communication service to a mobile phone located in a long curved tunnel. The leaky coaxial cable is installed in the tunnel from the point where the radio frequency signal transmitted from the antenna of the base station cannot reach. However, since the leaky coaxial cable has a loss along its length, when the tunnel length exceeds a certain length, the mobile telephone cannot receive a sufficiently strong radio frequency signal through the leaky coaxial cable.

Therefore, in the method of installing the relay device according to the present invention, the tunnel antenna is connected to the leaky coaxial cable at a point where the intensity of the radio frequency signal received through the leaky coaxial cable becomes a threshold. Then, the mobile phone located in the center of the tunnel can receive a sufficiently high frequency radio frequency signal through the tunnel antenna, and can transmit the radio frequency signal to the tunnel antenna.

FIG. 3 is an embodiment of a first relay device according to the present invention. As shown in FIG. 3, a first external antenna 210 located outside an entrance (point A) of a tunnel 200 and transmitting and receiving radio frequency signals is shown. Wow; A first repeater 220 connected to the first external antenna; One end portion (point B) of the first leakage coaxial cable 240 and the first leakage coaxial cable are connected to the first repeater through the first feed line 230 and transmit and receive radio frequency signals in the tunnel. It is connected to the other end (point C), and includes a first tunnel antenna 250 for transmitting and receiving radio frequency signals inside the tunnel. In addition, another embodiment of the second relay device according to the present invention includes a second external antenna 310, which is located outside the other entrance (point F) of the tunnel and transmits and receives radio frequency signals; A second repeater 320 connected to the second external antenna 310; One end portion (point E) is connected to the second repeater 320 through a second feed line 330, and a second leakage coaxial cable 340 and the second leakage that transmit and receive radio frequency signals in the tunnel. And a second tunnel antenna 350 connected to the other end (point D) of the coaxial cable 340.

Figure 4 shows an example of the tunnel to which the present invention is applied, (A) is a tunnel having inlet A and F, the bend is severe and 2.4Km in length, (B) is 3.8m in height, the width is In a tunnel with 6 m, a cross-sectional view of 1-1 'is shown.

The first or second external antennas 210 and 310 receive a radio frequency signal from a base station and transmit the radio frequency signal to the first or second repeater 220 or 320 through a feed line. The repeater amplifies the radio frequency signal and transmits the first or second feed line 230, 330 to the first or second leaky coaxial cable 240, 340 in the tunnel. The leaky coaxial cable transmits a radio frequency signal to the mobile phone in the tunnel, while transmitting a portion of the radio frequency signal to the first or second tunnel antennas 250 and 350. The tunnel antenna has a gain of 10 dB and amplifies a part of the radio frequency signal, transmits the result to a mobile phone in the tunnel, and preferably constitutes a yagi antenna.

The first repeater 220 is installed at one inlet (point A) of the tunnel. Assuming that the strength of the radio frequency signal received at point A is -75 dBm and the strength of the received signal is -85 dBm at the point 50 m introduced into the tunnel (point B), the gain of the first external antenna 210 is 13 dB and the first If the gain of the repeater 220 is 90dB, the height loss of the first leaky coaxial cable 240 is -60dB, and the gain according to the length of the leaky coaxial cable is -5dB for every 100m, the termination of the first leaky coaxial cable having a length of 1Km The strength of the radio frequency signal received at is -82 dBm. In this case, the service area by the first leaky coaxial cable is 950 m. However, if the gain of the first tunnel antenna 250 connected to the end (point C) of the first leaky coaxial cable is 10 dB, considering the tunnel antenna, the strength of the radio frequency signal received at the point C is -12 dBm. Then, when the threshold of the radio frequency signal that the mobile phone can receive the mobile communication service is -85dBm, the service area by the first tunnel antenna is 350m, and the first service area by the first relay device is 1300m. do.

Similarly, the second repeater 320 is installed at the other inlet (point F) of the tunnel. When the strength of the radio frequency signal received at the point F is -80 dBm and the strength of the received signal is -85 dBm at the point 25 m introduced into this tunnel (point E), the gain of the second external antenna 310 is 13 dB and the first If the gain of the repeater 320 is 90 dB and the height loss of the second leaky coaxial cable 340 is -60 dB and the gain according to the length of the leaky coaxial cable is -5 dB for every 100 m, the second leaky coaxial cable having a length of 0.9 km The strength of the radio frequency signal received at the termination is -82 dBm. In this case, the service area by the second leaky coaxial cable is 875 m. However, if the gain of the second tunnel antenna 350 connected to the end of the second leakage coaxial cable (point D) is 10 dB, considering the tunnel antenna, the strength of the radio frequency signal received at the point D is -12 dBm. Then, when the threshold value of the radio frequency signal at which the mobile phone can receive the mobile communication service is -85 dBm, the service area by the second tunnel antenna is 350 m, and the service area by the second relay device is 1225 m.

As a result, the length of the total service area by the first and second relays shown in Fig. 3 is 2525 m, which is sufficient to provide a mobile communication service in a tunnel having a total length of 2400 m. That is, the first and second relays maintain the intensity of the received signal at -85 dBm or more in the entire interior of the tunnel having a total length of 2400 m.

The relay device according to the present invention operated as described above should be installed according to the terrain of the tunnel. This is to prevent waste of investment in unnecessary elements. 5 is a flowchart illustrating a method of installing a relay device according to the present invention.

In step s110, the installer first analyzes the internal environment of the tunnel. Analyzing the internal environment of the tunnel is divided into measuring the length, height, and width of the tunnel, and measuring the propagation environment near the tunnel entrance. Measuring the length, height and width of the tunnel is the basis for calculating the equipment (feeder, leaky coaxial cable) required for the repeater. In addition, the installer measures the radio wave environment such as the strength of the radio frequency signal received from the base station, the strength of the pilot signal and the strength of the radio frequency signal received from the mobile telephone at both entrances of the tunnel. At this time, the radio wave environment measured at both entrances serves as a criterion for selecting a good entrance so as to have a reception level. The installer installs an external antenna and repeater outside of the good entrance to the reception level at both entrances of the tunnel. However, when the length of the tunnel is very long, as shown in Fig. 3, both relays are provided at both entrances of the tunnel.

In step S120, the installer configures an external antenna for transmitting and receiving radio frequency signals and a repeater connected to the external antenna outside the tunnel entrance according to the analysis result, and leaks in the tunnel in step S130. Install coaxial cable. In this case, the leaky coaxial cable is a point where the strength of the radio frequency signal received from the base station becomes a threshold (for example, -85 dBm) (point B), and the point where the strength of the radio frequency signal received through the leaky coaxial cable becomes a threshold ( Installed to point C). Although leaky coaxial cable is generally installed at the center of the tunnel ceiling, the higher the height (vertical separation distance) from the ground, the greater the loss due to the height. If the height of the leaky coaxial cable is reduced by half, the loss due to height is reduced by 6 dB. Therefore, install leaky coaxial cable on the side of the tunnel. However, if the width of the tunnel is wide enough that radio frequency signals transmitted by the leaky coaxial cable cannot reach the opposite side, then the leaky coaxial cable should be installed in the center of the tunnel ceiling.

In step (s140), if a repeater is connected to the inlet end of the installed leaky coaxial cable using a feeder, the leaky coaxial cable is connected to the radio frequency signal through the external antenna 210 and the repeater 220 and the feeder 230. And radiate the received radio frequency signal into the tunnel. Since the tunnel antenna must provide the service from the point (point C) where the strength of the radio frequency signal received by the mobile telephone through the leaky coaxial cable becomes a threshold, in step S150, the inside of the tunnel of the installed leaky coaxial cable The tunnel antenna 250 is connected to the side end portion.

If the tunnel is very long, repeaters should be installed at both entrances to the tunnel. Therefore, at the other entrance of the tunnel, repeating the above steps s110, s120, s130, s140 and s150, another relay device 310, 320, 330, 340, 350 is replaced. Install. Then, the tunnel antenna 250 and the tunnel antenna 350 provide the mobile communication service to the mobile phone in the central portion of the tunnel, the point C to the point D.

After the repeater is installed, power is supplied to the repeater, which relays the radio frequency signal to the leaky coaxial cable and tunnel antenna. At this time, the radio wave environment inside the tunnel is measured to confirm whether the mobile communication service is normally provided. If the area of the radio frequency signal received in the tunnel is less than the threshold (shaded area) is found, increase the gain of the repeater by a certain value and measure the propagation environment in the tunnel again. This measurement and increase is repeated until no shadow is found inside the tunnel.

That is, in the installation method according to the present invention, the installation of the leaky coaxial cable starts from the point where the intensity of the radio frequency signal received from the base station is less than or equal to the threshold, and the intensity of the radio frequency signal received through the installed leaky coaxial cable is The tunnel antenna is installed at a point below the threshold.

The present invention can be variously modified and can take various forms and only the specific embodiments thereof are described in the detailed description of the invention. It is to be understood, however, that the present invention is not limited to the specific forms mentioned in the detailed description of the invention, but rather includes all modifications, equivalents, and substitutions within the spirit and scope of the invention as defined by the appended claims. It should be understood to do.

In the present invention operating as described above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The installation method according to the present invention provides a mobile communication service in a tunnel by a leaky coaxial cable when the strength of a radio frequency signal received from a base station is less than or equal to a threshold, and provides a radio frequency signal received through the installed leaky coaxial cable. If the strength is less than the threshold is installed by the tunnel antenna to provide a relay device for providing a mobile communication service in the tunnel.

Therefore, the relay apparatus according to the present invention combines a leaky coaxial cable and a tunnel antenna to provide a good quality mobile communication service in a tunnel long enough to bend and have a long length such that the leaky coaxial cable cannot transmit a radio frequency signal of sufficient strength. It is possible to ensure the continuity of calls of mobile phones moving inside the tunnel.

Claims (10)

In a cellular mobile communication system comprising a mobile phone and a base station for providing a mobile communication service to the mobile phone using a radio frequency, An external antenna located outside the tunnel entrance; A repeater connected to the external antenna; A leakage coaxial cable having one end portion connected to the repeater through a feeder line and transmitting and receiving a radio frequency signal in a tunnel; And And a tunnel antenna connected to the other end of the leak coaxial cable, the tunnel antenna transmitting and receiving radio frequency signals inside the tunnel. In a cellular mobile communication system comprising a mobile phone and a base station for providing a mobile communication service to the mobile phone using a radio frequency, Analyzing the internal environment of the tunnel; Configuring an external antenna for transmitting and receiving radio frequency signals and a repeater connected to the external antenna, outside the tunnel entrance, according to the analysis result; Installing a leaky coaxial cable along the tunnel; Connecting a repeater to the inlet end of the installed leaky coaxial cable using a feedline; and And connecting a tunnel antenna to an inner end portion of the tunnel of the installed leaky coaxial cable. The method of claim 2, wherein the analyzing comprises: Measuring the length, height, and width of the tunnel; A method for installing a relay device for a mobile communication service in a tunnel area, comprising measuring a radio wave environment near a tunnel entrance. The method of claim 3, wherein the analyzing comprises: According to the measured propagation environment, the mobile communication service in the tunnel area, which selects the entrance of the tunnel having the stronger intensity of the received radio frequency signal among the entrances of the tunnel as the entrance of the tunnel where the external antenna and the repeater are installed. How to install a relay device for. The method of claim 2, wherein the step of installing the leaky coaxial cable, Relay for mobile communication service in the tunnel area, where the leaky coaxial cable is installed from the point where the intensity of the radio frequency signal received from the base station becomes the threshold to the point where the intensity of the radio frequency signal received through the leaky coaxial cable becomes the threshold. How to install the device. 6. The method of claim 5, wherein the threshold is a minimum value of radio frequency signal power at which the terminal can receive a mobile communication service through a radio frequency signal. The method of claim 2, wherein the step of installing the leaky coaxial cable, A method of installing a relay device for a mobile communication service in a tunnel area, wherein a leaky coaxial cable is installed in a central portion of a ceiling inside a tunnel or on a side surface of a tunnel. According to claim 2, The installation method of the relay device, Configuring an external antenna for transmitting and receiving radio frequency signals and another repeater connected to the external antenna outside of another entrance of the tunnel; Installing a leaky coaxial cable in the tunnel; Connecting a repeater to an inlet end of the installed leaky coaxial cable using a feed line; And And connecting a tunnel antenna to a tunnel inner end portion of the installed leaky coaxial cable, wherein the relay device for the mobile communication service in the tunnel area. According to claim 2, The installation method of the relay device, Transmitting, by the repeater, the radio frequency signal received through the external antenna to the leak coaxial cable and the tunnel antenna; Radiating a radio frequency signal by the leakage coaxial cable and the tunnel antenna into a tunnel; Measuring the strength of a radio frequency signal received at each point within the tunnel; Increasing the gain of the repeater by a predetermined value when a region where the strength of the radio frequency signal is less than the threshold is found in the tunnel; And And ending the installation of the relay device if the area of the radio frequency signal smaller than the threshold is not found in the tunnel as a result of the measurement. In a cellular mobile communication system comprising a mobile phone and a base station for providing a mobile communication service to the mobile phone using a radio frequency, Analyzing the internal environment of the tunnel; Installing an external antenna for transmitting and receiving radio frequency signals outside the tunnel entrance according to the analysis result; Connecting a repeater to the external antenna; Connecting a leaky coaxial cable to the repeater using a feed line; and And connecting a tunnel antenna to the leaky coaxial cable.