JP2000068912A - Mobile communication system and radio repeater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a radio transmission loss, to reduce transmission line installation cost and to realize secure and stable communication/call by setting sewerage to be a ratio transmission line, installing prescribed reflectors at the right angles branch points of the sewerage, thereby constituting the transmission line. SOLUTION: A reflector A: 8 reflecting in one direction and a reflector B: 9 reflecting in two direction are properly arranged in the branch points of a sewer 13. In the reflectors A: 8 and B: 9, vertical and lateral sizes are set to be the length of one wavelength of a transmission radio frequency. They are miniaturized and reflection is made efficient. They are disposed to an upper part in the sewer so that the sewage flow is not obstructed. A radio repeater 2 executes transmission/reception with the radio base station by an intra- sewerage transmission/reception antenna 10 through the reflectors A: 8 and B: 9. Thus, a radio transmission line loss can be reduced even in the sewerage having a right-angled part. The element of the intra-sewerage antenna 10 is constituted of an orthogonal polarized wave. Thus, fading is reduced and stable and secure data communication is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system using sewage pipes and routes, and more particularly to a mobile communication system useful for mobile communication, portable telephone, car telephone, mobile radio, and the like, and a mobile communication system. Related to the configuration method.

[0002]

2. Description of the Related Art Conventionally, a base station of a mobile communication system is provided with a transmitting / receiving antenna at a place with a high visibility above the ground to secure a radio wave propagation distance, and assures a service area of the base station as wide as possible. We have been designing stations with a reduced number of stations.

However, with the spread of mobile communication systems in recent years, mobile communication systems of the microcell system have appeared, and a large number of base stations and radio repeaters constituting a small service area in accordance with effective use of frequency resources have been developed. The need to install has arisen.

[0004] For this reason, on the ground, it is becoming difficult to secure a place for installing the base station and the wireless repeater, and the base station and the wireless repeater can be easily installed, and the beauty of the cityscape is not spoiled. An installation method was required.

In such a situation, a sewer is used for a transmission line between an exchange or the like and a base station as shown in FIG. 6, an optical fiber cable and a power cable are laid in the sewer, and a manhole cover at a key point of the sewer. In addition, a device incorporating a base station device has been considered (Japanese Patent Laid-Open No. 5-227073). The manhole antenna device according to this publication is configured such that a part of a manhole cover attached to the sewer 23 is made dielectric, a transmitting / receiving antenna provided therein, an optical fiber cable provided in the sewer pipe, and an electric signal. To an optical signal,
An electric / optical / optical / electrical conversion device for converting an optical signal into an electric signal; amplifying a radio wave received by the transmitting / receiving antenna via the manhole cover; A low-noise amplifier that outputs the signal to the optical fiber cable via a conversion device; and an optical signal of the optical fiber cable is amplified via the electric-optical / optical-electrical conversion device. And a high-power amplifier transmitted to the lid. Further, the information communication system of this publication is characterized in that a plurality of the manhole antenna devices are provided at predetermined intervals and the manhole antenna devices are connected to each other.

According to FIG. 6, the information communication system includes a plurality of manhole antenna devices BS24 of a manhole type base station provided with a dipole antenna, a capacitor antenna, and the like, and lays an optical fiber cable 23 in a route of the sewer 13 to mutually communicate. The exchange MSC21 is provided with a base station controller BSC, and exchanges transmission signals with each manhole type base station 24 under the control of the base station controller BSC. The exchange MSC21 is connected to an external public telephone network. 22. Thus, it is disclosed that a manhole-type base station emits radio waves to perform communication with a mobile station to form a mobile communication network.

In a mobile communication system using the manhole cover as a base station, the manhole cover is directly connected to an optical fiber cable or the like. Had to be laid.

[0008]

In order to solve these problems, there has been proposed an apparatus which does not directly connect a manhole cover and an optical fiber cable or the like but transmits and receives information by adding a wireless transceiver or an optical transceiver in the middle of the optical fiber cable. (JP-A-9-261158, JP-A-9-289)
676). However, this conventional technique has the following problems. That is, a description will be given with reference to FIG.

Referring to FIG. 7, the optical fiber cable 23 and the manhole type base station 24 are connected to the manhole type base station 2.
4 and the optical fiber cable
Relay antenna 25 provided with electric conversion device and demultiplexing circuit
Although the transmission and reception are performed wirelessly and the connection is not directly established, a part where an optical fiber cable and a power cable for supplying power to the manhole type base station 24 are laid still remains in the sewer. That is, the inside of the sewer 13 is a closed space, and is not a straight line but is bent at a curve, a right angle, or the like, so that the radio propagation loss in the sewer 13 is very large.

[0010] Therefore, an optical fiber cable and a power cable are required in most of the inside of the sewer 13, and the problem that the cost and labor for laying these cables cannot be reduced remains.

An object of the present invention is to solve the above-mentioned problems, to reduce the cost and labor for laying the wiring in the sewer, and to ensure reliable and stable mobile communication and communication.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a mobile communication system using a sewer as a wireless transmission path, a mobile portable device, an antenna for transmitting / receiving ground radio waves to / from the mobile portable device, and a radio wave in the sewer. A repeater having an antenna for transmitting and receiving, and a radio base station for communicating with an antenna for transmitting and receiving radio waves in the sewer and a mobile communication switching center, and at the sewer junction that is bent at an angle such as a right angle A vertical and horizontal reflector having a length of one wavelength is provided.

A radio repeater for transmitting and receiving ground waves and underground radio waves includes an orthogonally polarized transmitting / receiving antenna element having a plurality of dipole antennas, and a reflector serving as a reflector of the transmitting / receiving antenna element. It is characterized by.

The present invention also relates to a mobile communication method using a sewer as a wireless transmission path, wherein the mobile portable device transmits and receives terrestrial waves, and the relay station for transmitting and receiving the terrestrial waves transmits terrestrial radio waves to and from the mobile portable device. An antenna for transmitting and receiving, and an antenna for transmitting and receiving radio waves in the sewer, relaying the terrestrial wave and the sewer, and a radio base station communicating with an antenna for transmitting and receiving radio waves in the sewer by the relay station A communication with an exchange is performed, and a reflector having a length of one wavelength in length and width is installed at the sewer branch point which is bent at an angle such as a right angle in the sewer.

The present invention also relates to a radio repeater for mutually transmitting and receiving terrestrial radio waves and underground radio waves, comprising: an orthogonally polarized transmitting and receiving antenna element having a plurality of dipole antennas for the underground radio waves; And a reflector serving as a reflection plate.

Further, the present invention provides a mobile communication system configuration method using an underground passage as a wireless transmission path, comprising:
A repeater having an antenna for transmitting and receiving radio waves on the ground with the mobile portable device and an antenna for transmitting and receiving radio waves in the underground passage, and communicating with an antenna for transmitting and receiving radio waves in the underground passage and a mobile communication switching center. A radio base station, and a reflector having a length of 1 wavelength in the vertical and horizontal directions is installed in the underpass, the radio wave transmitted from the repeater is reflected by the reflector, and the radio base station reflects the radio wave. A radio wave is received, and the radio wave transmitted from the wireless base station is received by an antenna of the repeater.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments according to the present invention will be described.
This will be described in detail with reference to the drawings.

[Structure of Embodiment] FIG. 1 is an overall block diagram of an embodiment according to the present invention. Referring to FIG.
The mobile station (MS) 1 is connected to a radio repeater (RPT) 2 by an antenna 9 via a radio line, and the radio repeater 2 is connected by an antenna 8 in a sewer 13 via a radio line of the same frequency as described above. And is connected to a radio base station (BS) 3 received by an antenna 7.

The mobile station 1 is also called a portable radio terminal, for example, a mobile phone or a PHS (Personal Handyphone Sy).
and a small and light transmitting / receiving unit, a signal processing unit, a control unit, a man-machine interface unit such as an earphone, a microphone, and a keyboard.

The radio repeater (RPT) 2 includes a radio transceiver and an antenna for the underground sewer, a radio transceiver and an antenna for the mobile station 1 on the ground, a control unit, and the like. Since the radio frequency is transmitted and received at the same frequency to the mobile station 1 on the ground and the radio base station (BS) 3 in the sewage system, it operates as a booster or a repeater. Especially when power supply is difficult, even if the ground and the underground are simply connected with an antenna as a simple repeater,
The effect of cavity propagation by the sewer may be exhibited,
Sufficient propagation characteristics can be obtained.

The radio base station (BS) 3 is connected to the sewer 1
3, a transmitting / receiving antenna 9, a base station amplifying device,
It is composed of a base station modulation / demodulation device, a signal processing device, a voice processing device and the like.

The base station control device (BSC) 4 is connected to the radio base station 3 and the mobile communication switching center (MSC) 5, and has a call processing function for call connection, the device 4 itself and the radio base station. 3. It is composed of an operation management function such as monitoring and control of the radio repeater (RPT) 2.

Further, the mobile communication switching center 5 is also connected to a public telephone network 6, and its functions include a calling / end detection function, a signal transmission / reception / routing function, a billing function, and a mobile subscription. Function of registering the current position of the mobile subscriber in the home memory, tracking connection function of reading out the home memory when receiving an incoming call to the mobile subscriber and connecting to the exchange where the mobile subscriber is located, and transmitting the subscriber (mobile) from all the radio base stations belonging to the exchange. Station)
, And a channel switching function that can continue communication even if a mobile subscriber moves in a zone.

FIG. 2 is an overall configuration diagram of the system according to the present embodiment. Referring to FIG. 2, the mobile switching center (M
SC) 5, a base station controller (BSC) 4, and a transmission line connected from the building where the radio base station (BS) 3 is installed to the public telephone network 6, a radio base station 3 and a radio repeater (RPT). 2
And a state of the sewer reflectors 8 and 9 installed at the sewage 7 constituting a wireless transmission path between the sewage and the branch point thereof.

Also, the installation form of the wireless repeater 2 and the state where the wireless repeater 2 radiates radio waves to the ground are shown.

FIGS. 3 and 4 are detailed views showing the state of attachment of the reflector in the sewer and its structure. Referring to FIGS. 3 and 4, as shown in FIG. 3A, the sewer reflectors 8, 9 include a sewer reflector A8 that reflects in one direction of the sewer at the branch point, and FIG. ), There are two types of reflectors B9 in the sewer that reflect in both directions of the sewer, and the vertical and horizontal dimensions of each reflector are the length of one wavelength of the radio frequency propagating in the sewer 13. It is configured. Also, in FIG.
Is performing wireless transmission / reception to / from the wireless base station by the transmission / reception antenna 10 in the sewer, and propagates in the sewer using the reflection plates 8 and 9 in the sewer.

The mounting positions of the reflector A8 and the reflector B9 in the sewer are within the range of the radio propagation path in the upper part of the pipe which does not interfere with the sewage flowing in the sewer as shown in the figure. is set up. Further, as shown in FIG. 4, even when the sewer 13 is a cylindrical drainage pipe, and is bent at a right angle in a horizontal plane, or provided with a shunt or a composite path, FIG. As shown in FIG. 4, the reflectors 14 and 15 are arranged so that the radio wave can be reflected and propagated in one direction at a time, and the one-way reflector 14 and the two-way reflector 16 are arranged as shown in FIG. Thus, wireless transmission can be realized according to the piping. In this case, there is no particular problem in the shape of the sewer, and it may be not only a cylinder but also a rectangle or a polygon.

FIG. 5A is a conceptual cross-sectional view of the wireless repeater 2, and FIG. 5B is a plan view of a part thereof viewed from the sewer side, and is attached to the back surface (sewer side). 1 shows the structure of a transmitting / receiving antenna in a sewer.

In FIG. 5A, the antenna element 12 in the sewage is transmitted from the reflector 11 to the transmission / reception radio wave wavelength λ of 0.25λ.
, Are mutually relayed by the wireless repeater 2, and are transmitted and received to and from a terrestrial wave by a circular patch antenna (annular antenna) 14. In this case, the wireless repeater 2 is provided with an impedance matching interface between the sewer antenna 12 and the circular patch antenna (annular antenna) 14 as a passive repeater to provide a simple system without power supply. Constitute. On the other hand, as an active repeater, when power is supplied from a power supply (not shown) and transmission and reception are performed, a reception signal supplied from an antenna is highly sensitively received by a low noise figure reception unit and the sewer side is received. And / or power up and output to each antenna on the ground side as a terrestrial wave. The manhole board 15 separates the ground from the underground, and the circular patch antenna (annular antenna) 14 is housed in an insulator, so that unevenness can be avoided in order to maintain the flatness on the ground. In addition, a circular patch antenna (annular antenna) 14
Have a horizontal radio wave radiation pattern.

Referring to FIG. 5 (b), the reflector 11 of the transmission / reception antenna in the sewer is attached to the casing of the wireless repeater 2 incorporated in the manhole board 15,
On the front surface of the reflector 11, a plurality of transmission / reception antenna elements 12 in the sewer disposed at a position (0.25λ) where the reflected radio wave from the reflector 11 is most efficiently received.

The transmitting / receiving antenna element 1 in the sewer
In No. 2, two dipole antennas are arranged at a right angle so as to be orthogonally polarized, and the two dipole antennas are electrically combined to form one antenna element.

Further, the main body of the transmitting / receiving antenna 10 in the sewage system of the present embodiment is configured by electrically combining a plurality of the above antenna elements. When the antenna gain is obtained and the radio wave propagates in the sewage system, a plurality of paths are required. Fading to generate multi-beam radio waves due to generation (fluctuation in electric field strength of propagating radio waves)
It plays a role in prevention.

[Operation of this Embodiment] The operation of this embodiment will be described with reference to FIGS. Usually, when the sewer is used as a radio propagation path, it is basically restricted by a problem of radio wave propagation except for a place where some measures are taken. That is, although the propagation loss is not so large in the sewage system in the straight section, the radio propagation loss becomes large when the sewer is branched or bent, so that it cannot be used.

In order to solve such a problem, it is possible to secure the electric field intensity in the bent sewer by placing a reflector at a branch point in the sewer.

In particular, in order not to disturb the function of flowing the sewage smoothly, which is an essential function of the sewage system, a reflector having a dimension as small as possible is required.

For this purpose, a reflector having a size that resonates with radio waves propagating in the sewerage is effective, and the reflection efficiency is ensured by setting the vertical and horizontal dimensions of this reflector to one wavelength of the propagating radio wave. are doing.

Next, the operation of the transmitting / receiving antenna in the sewer will be described with reference to FIG. Referring to FIG. 5, first, a sufficient antenna gain is required to cope with the propagation loss in the sewer. The following measures have been taken to ensure this. (1) The antenna reflector 11 as large as possible is provided on the rear surface of the wireless repeater. (2) A plurality of antenna elements 12 are provided at positions 0.25λ away from the reflector. (3) The plurality of antenna elements are connected and electrically combined.

The fading that occurs in the process of propagating through the sewer, which is a closed space, becomes a problem. In particular, the fluctuation of the amount of sewage flowing in the sewer is irregular, and this effect is added to cause a large fading, which causes a large fluctuation of the electric field strength in transmission and reception.

The surface of the radio repeater is a manhole cover and has the rigidity as a part of an original road, and has an insulating property for receiving radio waves from a mobile station. A circular patch antenna (annular antenna) 14 is provided while insulating asphalt or the like is embedded in the surface of a concrete plate or a manhole board, and radiates and receives in a horizontal polarization pattern. Thus, by combining the signal obtained by combining the transmitting and receiving antenna elements with the combined wave of the transmitting and receiving antennas on the back surface, it is possible to exhibit a role as a wireless repeater.

To cope with this, the following measures have been taken. (1) The transmitting and receiving antennas are not of a single polarization but of an orthogonal polarization type, and two dipole antennas are arranged at right angles. (2) The two dipole antennas arranged at a right angle are connected and electrically combined.

As described above, it is possible to correct the electric field intensity variation between orthogonal polarizations due to the difference in polarization characteristics in a special radio wave propagation environment. In addition, wireless transmission loss can be significantly reduced in a wireless path in the sewer, such as undulation or a right-angled bend in the sewer, compared to a wireless path on the ground, particularly in an urban area.

In the above-mentioned embodiment, the sewer has been particularly described. However, the underground passage has not only the sewer but also an underground passage of a subway, an underground shopping mall, and the like, each of which has a manhole cover and an air hole. In this case, a similar effect can be obtained with a similar configuration.

[0043]

According to the present invention, a reflector having a vertical and a width of approximately one wavelength is provided at a sewer branch point which is bent at an angle such as a right angle, and the gain of the transmitting / receiving antenna in the sewer is sufficiently increased. Since it can be secured, radio waves are emitted from the radio base station 3 into the sewer and transmitted to the radio repeater 2 installed on the manhole cover far away, so that not only a straight line but also a curved line, a right angle, and other complicated turns. Wireless transmission loss in the existing sewer system can be reduced, and as a result, a mobile station can be connected to a public telephone network via a wireless base station and an exchange.

Further, by forming the transmitting and receiving antenna element in the sewer with orthogonal polarization, fading can be canceled out, so that it occurs when a sewer closed in concrete or the like is used as a wireless transmission line. Very large fading can be reduced, stable electric field strength in transmission and reception can be obtained, and the connection between the mobile station and the public telephone network can prevent reflection attenuation by buildings and houses on the ground, enabling stable and reliable communication or data communication It can be.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a mobile communication system according to an embodiment of the present invention.

FIG. 3 is a schematic block diagram of a mobile communication system according to an embodiment of the present invention.

FIG. 4 is a schematic block diagram of a mobile communication system according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram of a transmitting / receiving antenna according to an embodiment of the present invention.

FIG. 6 is a block diagram of a conventional mobile communication system using sewerage.

FIG. 7 is a block diagram of a conventional mobile communication system using sewerage.

[Explanation of symbols]

 Reference Signs List 1 mobile station (MS) 2 radio repeater (RPT) 3,24 radio base station (BS) 4 radio base station controller (BSC) 5,21 mobile communication switching center (MSC) 6,22 public telephone network 8 in sewer Reflector A 9 Reflector B in sewerage system 10 Transmitter / receiver antenna in sewerage system 11 Reflector of transmitter / receiver antenna in sewerage system 12 Transmitter / receiver antenna element in sewerage system 13 Sewerage 14 Reflector 15 One-way reflector 16 Bidirectional reflector 17, 18, 19 Transmitter / receiver antenna 23 Optical fiber cable and power cable

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference)

Claims (8)

[Claims] 1. A mobile communication system using a sewer as a wireless transmission line, a repeater having a mobile portable device, an antenna for transmitting and receiving radio waves on the ground to and from the mobile portable device, and an antenna for transmitting and receiving radio waves in the sewer. And an antenna for transmitting and receiving radio waves in the sewer, and a radio base station for communicating with a mobile communication switching center. The sewer branch point bent at an angle such as a right angle has a vertical and horizontal length of one wavelength. A mobile communication system characterized in that a reflection plate is installed. 2. The mobile communication system according to claim 1, wherein the reflector is a one-way reflector or a two-way reflector. 3. The relay station according to claim 1, wherein the relay station has a function of an orthogonal polarization antenna provided in the sewer and a reflector for reflecting radio waves of the orthogonal polarization antenna.
A mobile communication system according to claim 1. 4. A mobile communication method using a sewer as a wireless transmission path, wherein a mobile portable device transmits and receives terrestrial waves, and a relay station that transmits and receives the terrestrial waves includes an antenna that transmits and receives terrestrial radio waves to and from the mobile portable device. An antenna for transmitting and receiving radio waves in the sewer, relaying the terrestrial wave and the sewer, and a radio base station comprising an antenna for transmitting and receiving radio waves in the sewer by the relay station and a mobile communication switching center; A mobile communication method, comprising: performing communication and installing a reflector having a length of one wavelength vertically and horizontally at the sewage branch point which is bent at an angle such as a right angle in the sewage system. 5. The reflection plate is a one-way reflection plate or a two-way reflection plate, and the relay station includes an orthogonal polarization antenna provided in the sewer and a reflection member for reflecting radio waves of the orthogonal polarization antenna. The mobile communication method according to claim 4, further comprising a function of a board. 6. A radio repeater for mutually transmitting and receiving a terrestrial radio wave and an underground passage radio wave, comprising: an orthogonally polarized transmission / reception antenna element having a plurality of dipole antennas for the underground passage radio wave; and a reflector of the transmission / reception antenna element. And a reflector comprising: 7. A mobile communication system configuration method using an underground passage as a wireless transmission path, comprising: a mobile portable device; an antenna for transmitting and receiving radio waves on the ground to and from the mobile portable device; and an antenna for transmitting and receiving radio waves in the underground passage. A repeater, an antenna that transmits and receives radio waves in the underpass, and a radio base station that communicates with a mobile communication switching center; and a reflector having a length of one wavelength vertically and horizontally is installed in the underpass. The radio wave transmitted from the repeater is reflected by the reflector, the radio wave is received by the radio base station, and the radio wave transmitted from the radio base station is received by the antenna of the repeater. A method for constructing a mobile communication system. 8. The method according to claim 5, wherein the reflector is a one-way reflector or a two-way reflector.