KR20030068334A - A Outer RF Repeater System - Google Patents

Abstract

PURPOSE: An earth type repeater system is provided to connect a donor unit with a remote unit by a single cable, and to differentiate a downlink transmission IF from an uplink transmission IF, thereby easily obtaining isolation. CONSTITUTION: A donor unit(100) receives a base station signal, converts an RF signal into a 70MHz IF, and transmits the 70MHz IF to a remote unit(200). The donor unit(100) converts a 140MHz IF inputted from the remote unit(200) into an RF, and transmits the RF to a base station. The remote unit(200) receives an RF signal from a terminal, converts the received RF signal into a 140MHz signal, and transmits the 140MHz signal to the donor unit(100). The remote unit(200) converts a 70MHz IF coming from the donor unit(100) into an RF, and transmits the RF to the terminal. The donor unit(100) and the remote unit(200) have AGC(Auto-Gain Control) functions to actively cope with external environments.

Description

Ground Repeater System {A Outer RF Repeater System}

The present invention relates to a terrestrial repeater system. More particularly, the present invention relates to a terrestrial repeater system capable of effectively communicating services by ensuring sufficient isolation.

In recent years, personal wireless mobile communication service can be made anywhere in the country, and the use of various repeaters in the area having an unfavorable condition for installing a base station between the cell (Cell) and the cell has been effectively improving the radio wave environment. However, the short distance between the radio antenna and the service antenna coming from the base station causes a mixture of the received radio wave and the service radio wave from the repeater's point of view, thereby not only providing high quality call service but also limiting the repeater call capacity. This phenomenon is caused by insufficient isolation. In general, the higher the isolation level, the better the service and call capacity can be obtained from the repeater.

1 is a block diagram showing a donor part and a remote part of a conventional repeater system. It consists of donor unit (donor unit unit 100) located within the service range of the base station (BTS) and a repeater unit located in the center of the service area (shading area) to be extended, and is operated in a forward-link manner. ) And up-link operation. In the forward operation, the base station receives the high frequency signal F1 sent by the base station from the repeater to prevent loop back of the input / output due to spill-over. It converts the frequency (F3) to the repeater to cover the shadow area, and the repeater receives the frequency (F3) and converts the original frequency signal (F1) transmitted by the base station from the high-frequency module in the repeater to service the subscriber. to provide.

Similarly, in the reverse operation, the repeater receives the high frequency signal F2 transmitted by the subscriber, converts it to another frequency F4 in the PCS frequency band, and transmits it to the donor unit in the service area, and the donor unit transmits the received frequency F4 to the original frequency. The signal is converted into the signal F2 and transmitted to the base station.

However, the conventional repeater system receives the donor part and receives the donor part signal from the remote part extending to the RF cable within 200m to serve the service through the service antenna. This method is performed between the donor part and the remote part. The loss is caused by the extension cable, which has to compensate for the gain at the remote part, and the distance between the donor part and the remote part has to be increased to further increase the isolation.

In addition, the conventional repeater receives the base station signal from the donor unit and changes only a small frequency (for example, 2.5 MHz) to be wirelessly transmitted to the remote unit located in the shadow area. Even in this case, the degree of isolation cannot be secured enough. In particular, when there is a signal source or a physical object acting as a radio interference in the wireless section between the donor unit and the remote unit, the quality of the call is reduced or the call is not made and thus cannot serve as a repeater at all.

The present invention attempts to break away from the solution through the distance between the donor and the remote just to ensure sufficient isolation that it must have to service optimal call quality in a terrestrial repeater.

Therefore, an object of the present invention is to ensure sufficient isolation in the terrestrial repeater system to effectively prevent mixing of radio waves.

1 is a block diagram showing a donor part and a remote part of a conventional repeater system;

2 is a view showing the concept of a repeater system according to the present invention, and

3 is a block diagram of a repeater system according to the present invention.

* Description of the symbols for the main parts of the drawings *

100: donor portion 200: remote portion

Technical solution of the present invention for achieving the above object, the donor (Donor) receives a high frequency signal (RF) from the base station to convert the intermediate frequency (IF) forward to the remote (remote) and the remote unit In the terrestrial repeater system that receives a high frequency signal (RF) from a terminal and converts it into an intermediate frequency (IF) and transmits it backward to the donor part, the donor part and the remote part are connected by a single cable, and the forward transmission intermediate frequency and the reverse direction It is characterized by different transmission intermediate frequencies.

In particular, it is preferable that the forward transmission intermediate frequency is 70 MHz and the reverse transmission intermediate frequency is 140 MHz.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention for achieving the above object will be described in detail.

2 is a view showing the concept of a repeater system according to the present invention, the donor unit 100 receives the base station signal and converts the RF signal into an intermediate frequency of 70MHz and serves to deliver to the remote unit 200. On the contrary, the intermediate frequency of 140 MHz input from the remote unit 200 is converted into an RF frequency and transmitted to the base station. The remote unit 200 receives the RF signal from the terminal, converts it to 140 MHz, and transmits the converted RF signal to the donor unit 100. On the contrary, the 70MHz intermediate frequency coming from the donor unit is converted into the RF frequency and transmitted to the terminal. Both donor and remote parts are equipped with an auto-gain control function that can actively cope with the external environment.

In addition, the donor unit 100 located in the base station is connected to the remote unit 200 located in the service area with a single RF cable, and the donor unit 100 and the remote unit 200 are supplied with a reference frequency of 10 MHz. Keep motivated

3 is a block diagram of a repeater system according to the present invention, in which a block located in a left rectangular area is a donor unit 100 and a block located in a right rectangular area is a remote unit 200. The base station signal introduced through the duplex (110, 210) is converted to an intermediate frequency through a low noise amplifier and a phase synthesizer (Phase Lock Loop). The converted frequency adjusts the gain and is transmitted to the remote unit 200 through the RF cable. The remote unit 200 amplifies the weakened signal and performs up-converting to restore the intermediate frequency signal back to the RF signal using a frequency synthesizer, and selects an appropriate gain and transmits it to the terminal. In order to change 70MHz and 140MHz, the donor part 100 and the remote part 200 each have two frequency synthesizers.

Conventional wave repeaters receive base station signals from the donor and change only a small frequency (for example, 2.5 MHz) to be wirelessly transmitted to the remote unit located in the shadow area. Even in this case, the degree of isolation cannot be maximized as in the present invention. In addition, if there is a signal source or a physical object acting as a radio interference in the wireless section between the donor unit and the remote unit, the quality of the call can be reduced or the call can't serve as a repeater. On the contrary, the present invention maximizes the isolation by using a technique for transmitting a bidirectional frequency with low frequency mutual interference, and the donor part and the remote part, which consist of a wired network section, transmit high quality radio waves to any signal source and terrain of radio interference. Do this.

The following table shows the characteristics of the repeater system according to the present invention.

[table]

Donors Part Specification Specification Frequency range Forward direction 880.89-889.50 MHz 70 MHz, +/- 5 MHz 880.89-889.50 MHz Reverse 140 MHz, +/- 5 MHz 835.89-844.50 MHz 835.89-844.50 MHz Gain Ripple 3.5 dB, p-p Control step size (S / W) 30dB, 1dB Step 30dB, 1dB Step 60dB, 1dB Step Control error +/- 1.0dB +/- 1.0dB +/- 2.0dB Input power range Forward direction -75 to -45 dBm / total -35 to -5 dBm / total -75 to -45 dBm / total Reverse -35 to -5 dBm / total -75 to -45 dBm / total -75 to -45 dBm / total Noise Figure - - Gmax @ <7 dB Gmin @ <15 dB V.S.W.R 1.5: 1 Group Delay ≤5s Tx / Rx Isolation 110 dB

In general, isolation is a concept used to isolate two signals. For example, in the case of a duplexer, two signals are separated or separated as much as possible because the transmitting and receiving frequency signals are simultaneously moved back and forth in one element. It is necessary to do this, and it means the degree to which each signal separates when using multiple signals at the same time. In other words, the degree of isolation is used as a measure of how less interference with each other.

As shown in the above table, the Tx / Rx isolation according to the present invention is 110dB, and it can be seen that the Tx / Rx isolation is larger than 90dB, which is the Tx / Rx isolation of the conventional terrestrial repeater.

As described in detail above, according to the present invention, the conventional terrestrial repeater system receives a RF signal of a base station and receives a Dornor signal from a remote part which is extended by an RF cable within 200 m. This method causes a loss due to the extension cable between the donor part and the remote part. This loss has to compensate for the gain at the remote part, and increases the distance between the donor part and the remote part to increase the isolation. I was forced to.

The present invention receives the signal from the base station at the donor part and converts the RF signal to the IF signal, but the forward (base station-repeater-terminal) is converted to 70MHz and transmits the signal to the remote part, the 70MHz IF signal back to the remote part Performs service through service antenna by converting into RF signal. On the contrary, the reverse direction (terminal-relay-base station) in which the signal is transmitted from the terminal to the base station receives the terminal signal from the remote unit and converts the RF signal into an IF signal in the forward direction, but converts it to 140 MHz instead of 70 MHz, and transmits it to the donor unit. The donor unit converts the 140 MHz IF signal into an RF signal and transmits the signal to the base station. That is, the IF signal and the RF signal conversion method is used between the donor unit and the remote unit, and the forward and reverse transmission frequencies are differently transmitted at 70 MHz and 140 MHz, respectively.

As a result, by using radio waves of different frequencies, even if different signals are input, only the desired signals are output through the filter in the repeater. This can effectively prevent the mixing of radio waves.

Although the preferred embodiments of the present invention have been described in detail, the present invention is not limited to the forms and structures applied in the embodiments, and various modifications and changes can be made by those skilled in the art.

Claims (2)

A donor receives a high frequency signal RF from a base station, converts it into an intermediate frequency IF, and forwards the result to a remote unit. The remote unit receives a high frequency signal RF from a terminal to an intermediate frequency IF. In the terrestrial repeater system for converting and forwarding to the donor unit, The donor unit and the remote unit is connected by a single cable, the ground repeater system, characterized in that the forward forward intermediate frequency and the reverse forward intermediate frequency are different. The method of claim 1, The forward transmission intermediate frequency is 70 MHz, and the reverse transmission intermediate frequency is 140 MHz.