KR20020064019A - gain-dispersive RF repeater system - Google Patents

Abstract

PURPOSE: A gain distribution RF(Radio Frequency) relay system is provided to improve speech quality by preventing the oscillation phenomenon of a repeater by antenna feedback. CONSTITUTION: A previous relay device(200) connects to a base station(100), radiates a signal from the base station(100) in a predetermined direction to transmit the signal, and receives a signal transmitted from the predetermined direction. A last relay device(300) receives the signal from the predetermined direction, amplifies the received signal, and transmits the amplified signal to a plurality of subscriber terminals. The last relay device(300) receives the subscriber terminal, amplifies the received signal, radiates the amplified signal in the predetermined direction to transmit the signal.

Description

Gain-dispersive RF repeater system

The present invention relates to a gain distributed RF relay system, and more particularly, to provide an RF relay system for improving call quality by preventing oscillation of a repeater due to antenna feedback.

In the wireless communication field, CDMA (Code Division Multiplexing) technology and the revolutionary development of digital technology have made the fields of cellular and PCS technologies such as domestic and overseas large companies, data communication, wireless subscriber network (WLL) and frequency common communication ( TRS (TRS), etc. has emerged, and the airfield is at a stage where IMT-2000 project using satellite, called next generation mobile communication, is being pushed forward.

General wireless communication subscribers must be equipped with a base station, a wireless repeater and a terminal in order to make a call with the other party using their terminal through the wireless communication, and the configuration of such a general RF relay system is shown in FIG. It was.

The general RF relay system includes a repeater 900 for transmitting / receiving a high power signal from a base station 100 to a terminal (not shown) of a wireless communication subscriber, where the repeater 900 is a signal processing / amplification. The device 920 includes a first transmit / receive antenna 950 and a second transmit / receive antenna 980. The repeater 900 generally employs an isotropic or omnidirectional antenna having a wide radiation pattern in order to support a wide range of terminals in a unit area.

A problem in the general RF relay system as shown in FIG. 1 is that there is a possibility that an oscillation phenomenon may occur as the output signal of the repeater is fed back to the input and subjected to the amplification process again. Since the gain of the repeater itself must be limited, a problem arises in that the output cannot be increased, and thus the degradation of the call quality cannot be avoided.

In more detail, the oscillation phenomenon of the repeater occurs when the gain of the repeater is larger than the isolation coefficient between input and output. Here, the separation coefficient is a coefficient indicating the amount of return to the input during output, for example, 20 dB when the radiated power of 1/100 of the output returns to the input. At this time, if the gain of the repeater is greater than 20 dB, the oscillation phenomenon of the input output signal is re-amplified again. Therefore, the gain should not be higher than the separation coefficient. Thus, the separation coefficient may increase the gain of the repeater. Act as a limiting factor.

In addition, the oscillation phenomenon includes a forward oscillation phenomenon from the base station to the terminal direction and a reverse oscillation phenomenon from the terminal to the base station direction. In particular, the reverse oscillation phenomenon may be a serious problem because it may affect the base station. When oscillation occurs and the signal sent from the specific repeater to the base station becomes large, the gain must be increased to raise the output signal of another repeater to match the level of the same signal. Higher levels can cause other oscillations in the repeater, paralyzing the entire system and causing the repeater itself to fail.

In the case of the code division multiple access (CDMA) scheme, if the size of a signal varies from terminal to terminal, it may be more problematic because gain adjustment is required to adjust it to a similar level. An abnormal rise of an output signal due to the oscillation phenomenon may occur. If this occurs, it is difficult to adjust the gain of the repeater to compensate for the difference in the output signal resulting from adopting the above CDMA method.

In order to solve this problem, a method of employing an optical repeater has been proposed. In the case of an optical repeater, an input is used as an optical signal and an output is transmitted as a radio wave to prevent the output signal from affecting the input signal again. Let's make the basic configuration. Therefore, an optical fiber is required from the base station to the repeater or between the repeaters, and there is an advantage in that the signal can be easily transmitted even at an invisible distance, but it requires additional wires, resulting in an additional cost increase. The use of materials with high dielectric constants causes problems such as propagation delay (5.5usec / km), and there are problems such as deterioration of call quality at the boundary between the optical path area and the wireless area.

Another solution proposed is a variable frequency repeater, which uses a frequency in a region not currently used by changing the frequency between the input and output of the repeater to prevent oscillation by eliminating interference between the input signal and the output signal. Therefore, the use of such a method requires an additional frequency allocation (FA), which cannot be used for an actual call, resulting in a decrease in frequency efficiency and an additional use and maintenance cost of an unnecessary propagation area.

The present invention has been made to solve such a problem, and it is possible to increase the transmission and reception sensitivity between antennas to directly transmit and receive signals by introducing high-directional transmission and reception of radio waves and without adopting additional frequency allocation or optical path not used in a call. Enhances the separation of signals between repeaters I / O and maintains the overall gain of the signal more than or equal to the existing method without increasing the gain of each relay by increasing the number of steps for relay in the path from the base station to the subscriber's terminal. By doing so, the gain of each relay means can not be increased compared to the separation coefficient to prevent oscillation at the source and thereby to provide a gain distributed RF relay system for maintaining call quality.

1 is a block diagram showing the configuration of a general RF relay system.

Fig. 2 shows the construction of one preferred embodiment of the gain distribution relay system according to the present invention.

Figure 3 shows a configuration of another preferred embodiment of the gain distribution relay system according to the present invention.

Fig. 4 shows the construction of another preferred embodiment of the gain distribution relay system according to the present invention.

In order to achieve this object, a gain distributed RF relay system according to an aspect of the present invention is a gain distributed RF relay system for relaying forward and reverse wireless communication service signals between a base station and a plurality of subscriber stations. A preceding relay means connected to the base station by directionally radiating a signal from the base station in a predetermined direction, and receiving a signal transmitted from the predetermined direction; And receiving a signal from a predetermined direction, amplifying the received signal, transmitting the amplified signal to the plurality of subscriber stations, receiving a signal from the subscriber station, amplifying the received signal, and amplifying the signal. And final relay means for transmitting the signal by directional radiation in the predetermined direction.

In addition, a gain distributed RF relay system according to another aspect of the present invention, the signal from the preceding relay means, the final relay means and a predetermined first direction, amplifies the received signal, amplified signal At least one relay means for transmitting by directionally radiating in a second predetermined direction, receiving a signal from the second direction, amplifying the received signal, and transmitting by directionally radiating an amplified signal in the first direction. It includes more.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 shows the configuration of one preferred embodiment of a gain dispersion relay system according to the present invention.

This embodiment is composed of the base station 100, the preceding relay means 200, the final relay means 300 and provides a service for transmitting and receiving a radio signal with a plurality of subscriber stations (not shown) in the region from the last relay means .

In general, the base station 100 is configured to have a main antenna having an isotropic or omnidirectional radiation pattern in order to spread the radio evenly over a wide area. It is configured to include a preceding relay means 200 is connected to the base station and radiates a radio wave having a large directional (directional) in a specific direction of low transmission and reception sensitivity. Here, the preceding relay 200 has a signal processing / amplifying device 220 and an antenna 250 for radiating a large directivity radio wave, the general array antenna having a directivity such as a patch array (patch array) Can be used here.

In addition, the signal transmitted from the preceding relay means 200 is received by the antenna 350 of the final relay means 300, and transmitted to the terminal of each subscriber through the antenna 380 via the signal processing / amplifying device 320 do. Here, the antenna 250 of the preceding relay means and the antenna 350 of the final relay means transmit and receive polarization of the transmitted and received radio waves in order to increase reception sensitivity and to avoid oscillation caused by the inflow of unnecessary signals from other antennas. It is preferable to configure the antenna having high directivity in which the polarization directions coincide with each other.

In the reverse direction, the signal transmitted from the terminal of each subscriber is received by the antenna 380 of the final relay means 300, and the preceding relay means 200 via the antenna 350 via the signal processing / amplification device 320. ) And is transmitted to the base station 100 via the signal processing / amplifying device 220 of the preceding relay means 200. In this case as well, the antenna 350 of the final relay means 300 and the antenna 250 of the preceding relay means 200 are constituted by an antenna having a high directivity in which polarization directions of transmission and reception radio waves coincide with each other. It can be avoided to increase the transmission and reception sensitivity.

Figure 3 shows the configuration of another preferred embodiment of the gain distribution relay system according to the present invention.

The present embodiment further includes a relay means 600 which relays a signal in the middle, because the distance between the base station 100 and the final relay means 300 is far. However, in the drawing, only one relay means 600 is shown. In accordance with the plurality of relay means 600 may be further installed to improve the call quality.

Since the base station 100, the preceding relay means 200 and the final relay means 300 in this embodiment are the same as in the above embodiment, detailed description thereof will be omitted. The relay means 600 includes a first antenna 650, a signal processing / amplification device 620 and a second antenna 680, the first antenna 650 is transmitted and received with the antenna of the preceding relay means 200 In order to increase the sensitivity, the antenna has a high directional radiation pattern in the same polarization direction. In addition, the first antenna 650 and the second antenna 680 of the relay means 600 are different from each other in a polarization direction (for example, if one side is a horizontal polarization direction, the other side is a vertical polarization direction). The oscillation phenomenon can be prevented by preventing the output radio waves from one side from affecting the other side.

Similarly, in the case of including one or more relay means, a pair of antennas configured to send and receive signals to and from each other are configured such that the main directions of the radio waves face each other, and the polarization directions are matched to increase the transmission and reception sensitivity, The first antenna 650 and the second antenna 680 may be different from each other in the polarization direction to prevent the oscillation phenomenon.

Figure 4 shows the configuration of another preferred embodiment of the gain distribution relay system according to the present invention.

In this embodiment, one relay means 700 inputs / outputs signals to two antennas 780 and 790 which are different from each other in a main radiation direction by using a splitter 760. It is possible to relay transmission and reception radio waves between the base station 100 having a plurality of directions through the final relay means (300, 1000).

As described above, the oscillation phenomenon occurs when the gain exceeds the isolation coefficient, and it is required not to increase the gain in order to prevent the oscillation phenomenon. By adopting a plurality of relay means as in the present invention, the overall gain can be maintained without excessively increasing the gain of each relay means, and the oscillation phenomenon can be fundamentally prevented by keeping the gain low compared to the separation coefficient of each relay means. In addition, in order to prevent the oscillation phenomenon, the gain distribution relay system of the present invention adopts an antenna having a high directivity to reduce the rate of return of the output signal back to the input side. The other main aspect is to increase the transmission and reception sensitivity by matching the polarization direction of the receiving antenna, and in the case of two antennas of the same relay means that do not directly transmit and receive radio transmission signals to each other, they are configured so as not to be mutually affected by different polarization directions. Is another major aspect.

The gain distribution relay system according to the present invention can be modified and applied in various forms within the scope of the technical idea of the present invention and is not limited to the above preferred embodiment.

For example, it is possible to further configure a path to a plurality of final relay means by using a relay means employing a plurality of splitters of the preferred embodiment, and the technical idea of the present invention depending on how the path is configured. It is obvious that this is not a major factor in determining whether the range is within the range of.

In addition, the embodiments and drawings are merely for the purpose of describing the contents of the invention in detail, and are not intended to limit the scope of the technical idea of the invention, the present invention described above is common knowledge in the technical field to which the present invention belongs In the present invention, various substitutions, modifications, and changes are possible without departing from the spirit of the present invention.

The gain-distributed RF relay system according to the present invention improves the transmission and reception sensitivity between antennas that directly transmit and receive signals through the introduction of high-directional transmission and polarization of radio waves without the need for additional frequency allocation or use of optical paths not used in a call. Enhances the separation of signals between repeaters I / O and maintains the overall gain of the signal more than or equal to the existing method without increasing the gain of each relay by increasing the number of steps for relay in the path from the base station to the subscriber's terminal. By doing so, the gain of each relay means cannot be increased compared to the separation coefficient, thereby preventing the oscillation from occurring and thereby maintaining the call quality.

Claims (9)

A gain distributed RF relay system for relaying forward and reverse wireless communication service signals between a base station and a plurality of subscriber stations, A preceding relay means connected to the base station and transmitting by directionally radiating a signal from the base station in a predetermined direction and receiving a signal transmitted from the predetermined direction; And Receive a signal from a predetermined direction, amplify the received signal, transmit the amplified signal to the plurality of subscriber stations, receive a signal from the subscriber terminal, amplify the received signal, amplified And a final relay means for transmitting the signal by directionally radiating the signal in the predetermined direction. The method of claim 1, Receives a signal from a first predetermined direction, amplifies the received signal, transmits the amplified signal by directional radiation in a second predetermined direction, receives a signal from the second direction, and And one or more relaying means for amplifying the signal and transmitting by directionally radiating the amplified signal in the first direction. The method of claim 1, And the preceding relay means and the final relay means include an antenna having a directional radiation pattern. The method of claim 2, And said at least one relay means comprises an antenna having a directional radiation pattern. The method of claim 4, wherein The at least one relay means each has a directional radiation pattern and includes a first antenna for transmitting and receiving a signal in the first direction and a second antenna for transmitting and receiving a signal in the second direction, the first antenna And the second antenna are configured to vary the polarization direction of the radio wave to minimize the output signal from one of the first antenna and the second antenna to be fed back to the other antenna. The method of claim 3, The antennas having the directional radiation patterns of the preceding relay means and the final relay means are configured such that the polarization directions of the radio waves are equal to each other so as to increase the reception sensitivity of the other antenna with respect to a signal from one of the antennas. Gain Distributed RF Relay System. The method of claim 5, The antenna having the directional radiation pattern of the preceding relay means and the first antenna of the relay means closest to the preceding relay means are configured such that the polarization directions of the radio waves are the same with respect to a signal from any one of the antennas. Gain-distributed RF relay system that increases the sensitivity of the other antenna. The method of claim 7, wherein In the at least one relay means, the two adjacent relay means are configured such that the second antenna of one of the relay means and the first antenna of the other relay means have the same polarization directions of the radio waves so as to be equal to each other. A gain distributed RF relay system that increases the sensitivity of the other antenna to signals from the antenna. The method of claim 8, The antenna having the directional radiation pattern of the final relay means and the second antenna of the relay means closest to the final relay means are configured such that the polarization directions of the radio waves are the same with respect to a signal from any one of the antennas. Gain-distributed RF relay system that increases the sensitivity of the other antenna.