KR100315684B1 - Rf system for mobile phone base station in cdma system for shadow area by using optical antenna - Google Patents

Abstract

PURPOSE: An RF(Radio Frequency) system for a mobile phone base station in a CDMA(Code Division Multiple Access) system for a shadow area by using an optical antenna is provided to offer a service of good quality without the distortion of a signal and offer the service without installing specific base stations in several areas of an underground space. CONSTITUTION: An AFEU(Antenna Front End Unit) performs a duplexer filtering. An LCX(Leakage Coaxial Cable) is installed in an underground tunnel and is used as a transmission and reception antenna. An optical antenna or a Yagi antenna transmits and receives a radio wave to the station building of several floors and a underground store. The AFEU is used in a base station and a remote system. The AFEU of the base station and the AFEU of the remote system are connected by an optical signal. The LCX and the Yagi antenna are connected to the AFEU. The optical antenna is connected by the optical signal.

Description

High Frequency System of Mobile Phone Base Station in Shadow Division Code Division Multiple Access System Using Optical Antenna

The present invention is a high frequency system structure of a mobile telephone base station that enables mobile telephone service in an area where service is not possible, which is a radio shading area, by matching a system with a leaky coaxial cable (LCX) and applying an optical antenna to the mobile telephone base station. In terms of design, in particular, it provides high quality service without signal distortion and provides service without installing a base station in various areas of the underground space.

Referring to Fig. 1, the operation of the high frequency system of the conventional mobile telephone base station is largely composed of a high frequency part and a digital part. The digital unit performs demodulation by receiving the received signal whose frequency is lowered from the high frequency signal to the intermediate frequency signal, modulates a baseband signal received from the base station controller, and transmits the modulated baseband signal to the high frequency unit.

The high frequency part raises the intermediate frequency signal and then amplifies the signal using a high power amplifier to filter the transmission signal with the transmission band pass filter. The transmit signal radiates through a transmit antenna.

The received signal is received through two receiving antennas, filtered by the reception bandpass filter, and the high frequency signal is lowered to an intermediate frequency signal. In this case, one transmit / receive bandpass filter is designed in a structure that occupies a large amount of space in the system because one and two are mounted in the system. In addition, a conventional mobile phone base station transmits and receives a signal through an outdoor antenna.

However, in this method, the signal radiated from the antenna is propagated in the free space so that it can be serviced only within a certain propagation area.If the subscriber is out of the propagation area, the service is impossible.If the mobile station is located in the underground space, the base station antenna is installed on the ground. Since the signal cannot propagate to the basement, even if the base station is installed in the basement to install the antenna in the basement, there is a problem that it is difficult to transmit and receive signals with the existing antenna in a subway station or a long tunnel divided into several floors.

Accordingly, an object of the present invention is to provide a good service without distortion of the signal and to provide a service without installing a separate base station in various areas of the underground space in order to solve the above problems.

1 is a high frequency system configuration of a conventional mobile telephone base station,

2 is a structural diagram of an optical antenna interface base station according to the present invention;

3 is a structural diagram of an optical fiber base station type base station according to the present invention;

4 is an optical antenna interface type base station configuration diagram;

5 is a block diagram of an optical fiber base station type base station.

According to an embodiment of the present invention for achieving the above object, a preferred embodiment of a code division multiple access (CDMA) system for a shadow area using an optical antenna is

An antenna front end (AFEU) for performing duplexer filtering;

An optical antenna for transmitting and receiving radio waves to various levels of history and underground shopping centers; And

Yagi antenna is included.

In the present invention, the base station and the remote system

A transmission band pass filter that filters the transmission signal;

A receive band pass filter for filtering the received signal;

A low noise amplifier (LNA) for low noise amplifying the received signal;

A directional coupler for coupling the signal; And

It is preferable to use an antenna ultra-short end including a 2-way power divider (2WPD) for distributing the received signal.

It is desirable to connect the high output amplifier output of the system to the leaky coaxial cable installed in the underground tunnel and apply the antenna first end of the system with the same transmit and receive paths to the system, so that the leaky coaxial cable can be used as the transmit / receive antenna to service even in the underground tunnel.

When the distance between the two regions to be serviced is within 2 km, it is preferable to serve with an optical antenna interface type base station.

Optical antenna interface base station

An optical antenna interface (OAI) for converting a high frequency signal installed at the base station and an optical signal of an optical antenna element to each other;

An optical antenna element (OAEU) installed in a shaded area; And

It is preferable to include an optical antenna interface remote system that is installed at a remote location,

If the distance between the two areas to be serviced is more than 2km, it is preferable to serve with a fiber base station type base station,

The optical fiber base station type base station

An optical fiber base station hub mounted to the base station;

Yagi antenna coupled with the high output amplifier output; And

It is preferable to include a fiber-optic base station remote system that is installed at a remote location,

The optical antenna interface,

A power supply (AC / DC) for supplying power;

Eight optical transceiver units (XCVUs);

A high frequency combiner for coupling the high frequency signals received by the optical transceiver device; And

And a divider for distributing a high frequency signal of the high frequency coupler to the optical transceiver device.

The configuration of the present invention with reference to Figures 2 and 3, in order to transmit and receive a signal in the subway tunnel of the shaded area by applying the antenna first stage to the base station to match the transmission signal of the high power amplifier to the leaky coaxial cable installed in the underground tunnel . The base station changes the optical antenna structure according to the distance between regions in order to simultaneously service different regions. If the distance between two regions is within 2km, the service is provided by the optical antenna interface base station, and when the distance is more than 2km, the service is provided by the optical fiber base station type base station. The optical antenna interface type includes an optical antenna interface installed in a base station, an optical antenna unit installed in a shadow area, and an optical antenna interface remote system installed in a remote location. The optical fiber base station type base station is composed of a base station hub mounted on the base station, a yagi antenna connected to the output of the high power amplifier, and a fiber base station remote system installed at a remote location.

Since the remote system and the basic system transmit and receive with optical fiber, the signal attenuation is very small even at a long distance, so that it can provide high quality service without distortion of the signal.It is provided with up to 16 optical antenna units per base station. Provide service without base station installation.

Specific service method,

-It connects the high output amplifier output of the system to the leaky coaxial cable installed in the underground tunnel and applies the antenna first end with the same transmit / receive path to the system to use the leaky coaxial cable as the transmit / receive antenna.

-In the case of the optical antenna base station, the transmission signal of the high power amplifier unit is combined to convert the optical signal into the optical signal of the optical antenna interface and then transmit the optical signal to the optical antenna unit installed in the shadow area. Up to 16 optical antennas can convert and radiate optical signals back into high-frequency signals to provide services in multiple shaded areas. Install an optical antenna remote system consisting of an optical antenna element unit (OAEU), a high power amplifier, and an antenna ultra-short part within a distance of less than 2 km to serve as an optical antenna remote system installed in a shadow area of a remote location without installing a base station In addition, underground tunnels are provided with leaky coaxial cables. Matching with the leaky coaxial cable uses a high power amplifier and an antenna stage.

-In the case of the fiber base station type base station, it is applied when the distance between the remote system and the basic system is more than 2km, and the fiber base station converts and transmits the high frequency signal and the optical signal. The remote system converts it back into a high-frequency signal and connects it to the leaky coaxial cable using a high-power amplifier and antenna tip. The difference from the optical antenna interface type is that the Yagi antenna is installed instead of the optical antenna unit. Yagi antennas provide a divider between the base station and the leaky coaxial cable matching device to distribute the high power amplifier's transmit signal, providing service to shadowed areas without installing a separate base station.

Referring to the operation of the present invention with reference to Figures 2 and 3,

The high power amplifier receives a signal from the frequency rising converter of the base station and amplifies the signal to a predetermined level.

The antenna top end uses the same path for transmitting and receiving, and its internal structure includes a transmit bandpass filter and a receive bandpass filter for filtering the transmitted and received signals, a low noise amplifier for low noise amplifying the received signal, an optical antenna interface, and an optical fiber base station. It consists of a directional coupler (D / C) for coupling and a two-way power divider for distributing the received signal.

The receiver first stage distributes and supplies the received high frequency band signal, the received signal low noise amplification and the transceiver device.

The optical antenna interface located in the base station converts the high frequency signal of the base station and the optical signal of the optical antenna unit. The optical antenna unit provides a service by converting an optical signal of an optical antenna interface and a high frequency signal of a subscriber.

The optical antenna interface has a built-in power supply, up to eight optical transceiver devices, and one high-frequency coupler and one divider.

In an optical transceiver device connected to a DU (Digital Unit) block, conversion between a high frequency signal and an optical signal occurs, and each optical transceiver device provides two pairs of up / downlinks.

The high frequency combiner and divider combines the high frequency signals received at the optical transceiver device and, conversely, distributes the high frequency signals to the optical transceiver device.

The optical antenna unit receives the signal transmitted from the remote to the optical fiber and converts it into high frequency, and converts the high frequency signal received from the subscriber into the optical fiber and transmits it to the optical antenna interface.

The optical fiber base station is composed of a base station hub mounted to the base station and an optical transmitter and receiver located at a remote location. The signal transmitted from the base station hub to the optical fiber is converted into a high frequency signal by a remote optical receiver, and conversely, the high frequency signal received from the subscriber is transmitted from the remote optical transmitter to the base station hub by optical fiber.

The transmission path composed of high power amplifier and antenna first stage is connected to the leakage coaxial cable matching device and transmits the transmission signal to the leakage coaxial cable to provide mobile phone service in the terminal. In addition, a splitter is installed between the antenna first stage and the leaky coaxial cable matching device, and the distributed signal is transmitted to the antenna to provide a mobile telephone service in a space such as underground station.

According to the present invention operating as described above, it is possible to match with the leaky coaxial cable by using the antenna ultra-short part, so that the mobile telephone service can be performed even in the underground tunnel. Mobile phone service is possible in underground spaces, and in particular, because it transmits as optical signal without attenuation of signal, it can provide service to remote system without installing a separate base station even at a long distance. In the past, a single base system and several remote systems are available.

Claims (7)

An antenna ultra-short end to perform duplexer filtering; Leakage coaxial cable installed in the underground tunnel utilized as a transmitting and receiving antenna; It includes an optical antenna or Yagi antenna that transmits and receives radio waves to and from multiple levels of history and underground shopping centers. The antenna first end is used for a base station and a remote system, The antenna first end of the base station and the antenna first end of the remote system are connected by an optical signal, The leaky coaxial cable and the Yagi antenna are connected to the antenna first end, And the optical antenna is connected to the optical signal. A high-frequency system of a mobile telephone base station for a code division multiple access system for a shadow area using an optical antenna. The method of claim 1, wherein the antenna first end, A transmission band pass filter that filters the transmission signal; A receive band pass filter for filtering the received signal; A low noise amplifier for low noise amplifying the received signal; A directional coupler for coupling the signal; And A code division multiple access system for a shadow area using an optical antenna, comprising: a two-way power divider for distributing received signals. 2. The high frequency system of claim 1, wherein the code division multiple access system for a shadow area using an optical antenna serves as an optical antenna interface base station when the distance between two regions to be serviced is within 2 km. The method of claim 3, wherein the optical antenna interface base station An optical antenna interface for converting high frequency signals installed at the base station and optical signals of optical antenna elements; Optical antenna elements installed in shaded areas; And A code division multiple access system for a shadow area using an optical antenna, including an optical antenna interface remote system installed at a remote location. 2. The high frequency system of claim 1, wherein a code division multiple access system for a shadow area using an optical antenna serves as an optical fiber base station when the distance between two areas to be serviced is 2 km or more. The base station of claim 5, wherein An optical fiber base station hub mounted to the base station; Yagi antenna coupled with the high output amplifier output; And A code division multiple access system for a shadow area using an optical antenna, including a fiber-optic base station remote system installed at a remote location. The method of claim 4, wherein the optical antenna interface, A power supply for supplying power; Eight optical transceiver devices; A high frequency combiner for coupling the high frequency signals received by the optical transceiver device; And And a divider for distributing a high frequency signal of the high frequency coupler to the optical transceiver device.

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