KR100203568B1 - Device and control method of base station using low noise amplifying device of tower top - Google Patents

Abstract

The present invention relates to a tower top low noise amplifying device, a base station device using the same, and a control method thereof.

The present invention provides a tower top low noise amplification apparatus including a control board capable of reducing signal loss caused by a cable between an antenna of a base station and a system and inspecting a change in filter characteristics in a duplexer module, and a base station apparatus using the same.

Description

Tower tower low noise amplification device, base station device using same and control method

The present invention relates to a tower top low noise amplifying device, a base station device using the same, and a control method thereof, and more particularly, a tower top low noise amplifying device applied to a transmitting and receiving end of a mobile communication base station device. It is about.

Recently, the mobile communication technology of the Code Division Multiple Access (CDMA) system or the Personal Communication System (PCS) system has been widely used due to the advantage of being able to make calls in a mobile state.

In such a mobile communication network, all regions are divided into a plurality of cells, and one cell is provided in each cell. Each base station can communicate with a mobile communication switching center connected to a public network or another mobile communication switching center. Each base station monitors mobile stations in its cell and performs communication between a mobile communication switching center and a plurality of mobile stations.

1 shows a transmitting and receiving end of a general mobile communication base station.

As shown in FIG. 1, the transmitting and receiving end 2 is connected to the transmitting and receiving antenna (1). The transceiver 2 is a duplexer 21 which is connected to the antenna 1, a high power amplifier 22 which is connected to the duplexer 21 in order to form a transmission path, and An up converter 24, a low noise amplifier (LNA) 23 and a down converter 25 which are connected to the duplexer 21 in order to form a reception path.

The duplexer 21 is composed of a transmission filter and a reception filter, and performs a function of separating the received signal and the transmitted signal in addition to filtering the received or transmitted signal. As a result, transmission and reception are performed by one antenna 1.

The transmission signal Tx provided from the system of the base station (not shown) is converted into a high frequency signal by the up converter 24, and amplified by the high output amplifier 22, and then the duplexer 21 and the antenna 1 are removed. It is sent via. On the contrary, the signal received at the antenna 1 reaches the low noise amplifier 23 via the duplexer 21, and after the noise component is removed by the amplifier 23, is converted into a low frequency signal by the down converter 25. do. The signal output from the down converter 25 is provided to the system in the base station as a received signal Rx.

However, the capacity and rated power of such a base station is determined according to the size of the cell. For example, in a crowded area such as downtown, the cell size is very small, so the base station has a small capacity and rated power.However, in a small traffic area such as a farming village and a relatively small number of mobile stations, the cell size is very large. The capacity and rated output are also large.

In general, the antenna and the system of the base station are installed separately from the outdoors and indoors, such as buildings, are connected to each other by a cable. In this case, the length of the cable is also very long in the base station having a large capacity, and thus there is a problem that the signal loss is also very large by the cable. For example, the signal loss in a base station system is only about 1.8dB, but the signal loss by cable is about 6dB. In this case, the noise figure of the receiver rather than the transmitter is very low, and the reception radius of the base station is also narrowed.

In order to solve this problem, there is a method in which both the reception filter and the low noise amplifier are disposed toward the antenna to improve the reception noise figure. In this case, a dielectric filter or an air cavity filter is used as a reception filter. The dielectric filter has a sensitive change in filter characteristics according to an external temperature change, and the air cavity filter is not easily tuned. There is a problem.

The change in filter characteristics according to the external temperature change can be solved by using a superconductor (SCT) or a temperature compensation electric circuit (TEC). However, in the case of using superconductors, in order to maintain the characteristics of the superconductor (especially, absolute temperature of -273 ° C), a cooling device that occupies a large space such as a compressor must be installed, and the system is down once. It takes a lot of time to restart the chiller when it is removed. In particular, the phenomenon that the system is down is a 'service unavailable' state that should never occur in the mobile communication service, which greatly reduces the reliability of the mobile communication service.

In addition, in the case of using the temperature compensating element, the efficiency of the temperature compensating element itself is poor, the size of the heat sink is greatly increased, and the weight is much increased, and the cost is also about the cost of the superconductor. In addition, both methods have a fatal defect in that the entire receiving end of the base station is down when the module is down.

The invention is derived from the technical background as described above, which reduces tower signal loss by the cable between the antenna of the base station and the system, and includes a control board capable of inspecting changes in filter characteristics in the duplexer module. An object thereof is to provide a device and a base station device using the same.

1 is a configuration diagram schematically showing a conventional base station transceiver.

2 is a block diagram of a base station apparatus according to an embodiment of the present invention.

3 is an oscillation frequency diagram used in the base station apparatus of FIG.

Figure 4 is a flow chart illustrating a control method of the tower tower low noise amplifier according to an embodiment of the present invention.

The base station apparatus according to the present invention comprises a plurality of duplexer modules coupled to an antenna, a tower top low noise amplifier connected to each one, a control board and a base station system.

Each duplexer module has a reception path and a transmission path connected to an antenna, and a reception filter connected between the tower top low noise amplifiers is installed on each reception path. The receive path includes a bypass line through which the receive filter and the tower top low noise amplifier are passed, and a switch for selecting the same.

The control board inspects the reception filter of the duplexer module and the tower top low noise amplifier in the receiving path according to the command of the base station system, and has the following configuration to achieve this.

That is, the control board,

A switch for sequentially selecting a reception path of each sector according to a switching command and for introducing a frequency signal through the path;

A first phase synchronizing loop synthesizer which sequentially oscillates the center frequency and the left and right frequencies of the filter according to a frequency command and provides the switch to the switch;

A level detector for detecting a DC level of a signal fed back from a reception path of each sector and outputting the detected level;

Generating and outputting a switching command for the switch to sequentially select each sector, controlling the first phase-synchronizer loop synthesizer to oscillate the frequencies, and storing the DC level output from the level detector in advance. The microprocessor is configured to output a switching command for selecting a bypass path in the duplexer module and output a warning command to the base station system when there is a level change compared to the state level.

Therefore, the control board injects the oscillated frequency signal into each duplexer module sequentially, thereby checking the abnormality of the reception filter by comparing the level of the feedback signal with the steady state level. When there is a characteristic change in the reception filter, the bypass line in the corresponding duplexer module is selected so that the entire reception terminal of the base station apparatus is not down.

On the other hand, since the tower tower low noise amplifier is coupled to the antenna together, the structure is simple and can reduce the signal loss by the conventional cable.

The objects, features and advantages of this invention described above will become more apparent from the following detailed description of the embodiments with reference to the drawings.

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

2 is a block diagram of a base station apparatus according to an embodiment of the present invention;

3 is an oscillation frequency diagram used in the base station apparatus of FIG.

4 is a flowchart illustrating a control method of the tower tower low noise amplifier according to the embodiment of the present invention.

First, a configuration of a base station apparatus according to an embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 2, the base station apparatus according to the embodiment of the present invention is a tower top low noise amplifier 4 connected to an antenna 1, a duplexer module 3, and the duplexer module 3 to form a receive path. , Control board 5 and base station system 6.

The base station apparatus according to the embodiment of the present invention includes a three-sector antenna, six duplexer modules, and six tower top low noise amplifiers, but for convenience of description, one-sector antenna 1, one duplexer module 3, and Only the tower top low noise amplifier 4 is shown, and the technical scope of the present invention is not limited thereto.

More specifically, the duplexer module 3 includes a directional coupler 31 connected to the antenna 1, a directional coupler 33 connected to the base station system 6, and the directional couplers 31 and 33. A switch (34, 36) connected to and having a bypass line (35), a transmission filter (32) connected at both ends of the two switches (34, 36), and connected in parallel to the transmission filter (32) Together with the tower top low noise amplifier 4, it consists of the receive filters 37 and 38 which comprise a receive path.

The base station system 6 is provided with a base station duplexer 61 to which a high output amplifier 62 and a low noise amplifier 63 are connected, respectively.

The control board 5 includes a microprocessor 51 and a 1: 6 switch 53 and a microprocessor 51 which control a switching operation by the microprocessor 51 and provide a frequency signal to a corresponding duplexer module 3. Phase Locked Loop (PLL) Synthesizer 52 for providing a frequency signal to the switch 53 according to the output of the mixer, and a mixer for mixing the frequency signal fed back from the duplexer module 3 with the intermediate frequency. 55, a PLL synthesizer 54 for generating an intermediate frequency according to the output of the microprocessor 51 and providing the mixer 55 with the output signal of the mixer 55 to detect the DC level. 51 is provided to the level detector 56. The microprocessor 51 receives a bypass command / other control command from the base station system 6 and outputs a warning command and an address signal to the system 6.

In this embodiment of the invention, the duplexer module 3, the tower top low noise amplifier 4 and the control board 5 are installed in combination with the antenna 1, and for this reason are named tower tower low noise amplifiers. In the duplexer module 3, the reception filters 37 and 38 may be implemented as cavity filters. In this case, there is a problem in that the noise figure of the filter changes according to the external temperature change. In the present invention, the control board 5 generates a test signal to check the filter characteristics in the duplexer module 3 at predetermined periods, and when the test signal is fed back, the DC level is sensed to detect abnormality of the filter. To monitor. As a result, when there is an error in the filter, a warning command is transmitted to the base station system 6, and the signals received from the antenna 1 are controlled by controlling the switches 34 and 36 inside the duplexer module 3. Bypassing 37 and 38 and the tower top low noise amplifier 4 prevents the base station receiver from going down.

The operation of the base station apparatus will be described in more detail with reference to the frequency diagram of FIG.

FIG. 3 shows the frequency characteristics of the receive filters 37, 38 of FIG. In FIG. 3, a solid line shows a normal state, and a thin dotted line and a thick dotted line show a case where the center frequency F ₀ is shifted according to temperature change.

The microprocessor 51 includes left and right frequencies corresponding to the left and right sides of which the center frequency F ₀ of the filter and the cut-off of the filter are about 10 dB in the form of a look-up table. F ₁ , F ₂ ) are stored. In response to a command from the base station system 6, the microprocessor 51 starts an inspection operation and controls the switch 53 so that the switch 53 is one of six duplexer modules 3 and the PLL synthesizer. Connect the output of (52). The microprocessor 51 controls the PLL synthesizer 52 to sequentially oscillate the stored frequencies F ₁ , F ₀ , and F ₂ . The oscillated frequency signal is introduced through the directional coupler 31 of the corresponding duplexer module 3 through the switch 53.

When the filters 37 and 38 are normal, the switches 34 and 36 are connecting normal transmission / reception paths. Accordingly, the signal received at the antenna 1 is passed through the switch 34 to the base station system 6 via the switch 36 via the receive filter 37, the tower top low noise amplifier 4, and the receive filter 38. Is sent). The switching operation of the two switches 34, 36 is also controlled by the microprocessor 51. At the same time, the frequency signal introduced into the Rev1 terminal of the directional coupler 31 from the control board 5 is a switch 34, a receive filter 37, a tower top low noise amplifier 4, a receive filter 38, It is fed back to the mixer 55 of the control board 5 via the Fwd2 terminal of the switch 36 and the directional coupler 33.

The PLL synthesizer 54 and the mixer 55 are for converting a signal fed back from the duplexer module 3 to an intermediate frequency (IF), and thus the level detection of the signal is more effectively performed. That is, under the control of the microprocessor 51, the PLL synthesizer 54 oscillates the intermediate frequency, and the signal fed back by the mixer 55 and the intermediate frequency signal are mixed. The level detector 56 senses the DC level of the signal output from the mixer 55 and provides the resulting signal to the microprocessor 51. The microprocessor 51 compares the provided DC level with the values when the filters 37 and 38 of the duplexer module 3 and the tower top low noise amplifier 4 are normal, and determines whether there is an abnormality, and the result is determined by the base station system. (6) to send. At this time, if the filters 37 and 38 and the amplifier 4 are determined to be abnormal, a warning command is sent to the system 6. At the same time, by controlling the switches 34 and 36 so that the signal received from the antenna 1 is transmitted through the bypass line 35 between the two switches 34 and 36 and the filters 37 and 38. Bypass the amplifier (4).

The above check routine is performed for a few seconds, especially at the time when the subscriber is least, which may cause the base station receiving end to be less affected by the frequency signal oscillated from the control board 5.

Next, a method of controlling a tower tower low noise amplifying apparatus according to an embodiment of the present invention will be described with reference to the flowchart of FIG. 4. 4 is an algorithm performed by the microprocessor 51.

First, when a command is transmitted from the base station system 6, execution of the algorithm is started (S11). Subsequently, a command for oscillating the center frequency and the left and right frequencies f ₁ , f ₀ , and f ₂ of the predetermined filter is sequentially output (S12). Accordingly, as described above, the frequency signal oscillated by the PLL synthesizer 52 is introduced into the duplexer module 3 via the switch 53, the reception filter 37, the tower top low noise amplifier 4, It is fed back to the control board 5 via the receiving filter 38. The feedback signal is input to the level detector 56 to detect the DC level, and the detected DC level is input to the microprocessor 51.

The level of the feedback signal is stored as a steady state level at the corresponding oscillation frequency (S13). Then, it is determined whether the above operation is performed for all sectors (S14), and if not performed for all sectors in step S14, the next sector is selected through a sector selection switch control command S15, The process below the step S12 is repeated.

When it is performed for all sectors in the step S14, it waits temporarily and receives a check command from the base station system 6 (S21). In this case, the test command is input during the time when the subscriber's call is the least.

Next, a command for oscillating the center frequency and the left and right frequencies f ₁ , f ₀ , and f ₂ of the predetermined filter is sequentially output (S22). As described above, the feedback signal level is received (S23), and the input feedback signal level is compared with a previously stored steady state level (S24). If the feedback signal level and the steady state level in the step (S24) is the same, it is determined whether it is performed for all sectors (S25), if the result is performed for all sectors, and after reporting the result to the base station (S27), the algorithm To end (S28). If not performed for all sectors in step S25, the sector selection switch is controlled (S26) to repeat the process following step S22.

In addition, when the feedback signal level and the steady state level are different in step S24, the result is reported to the base station (S31), the bypass switch control command is output to the duplexer module, and a warning command is output to the base station system. (S32). Here, the difference between the feedback signal level and the steady state level means that the filter characteristics in the duplexer module have changed. The switches 34 and 36 in the duplexer module connect the bypass lines 35 by the bypass switch control command, so that the signals received from the antennas are changed from the reception filters 37 and 38 and the tower top low noise. It is input directly into the base station system by the bypass line 35 without passing through the amplifier 4. Then, according to the warning command notified to the system, the repairman replaces or repairs the filter with the changed characteristic.

Next, the microprocessor resets the previously stored level information (S33) and jumps to the step S12 to repeat the following process.

As described above, according to the present invention, even if the filter in the duplexer module is down due to a change in characteristics, the received signal is bypassed so that the entire receiver is not down, thereby increasing the reliability of the service. In addition, since the filter and the existing circuit element of a simple structure are used, it is easy to install the antenna and the price is low. In addition, since an expensive superconductor or a temperature compensating element is not used, miniaturization is possible and thus maintenance is easy.

Although this invention has been described with reference to the most practical and preferred embodiments, the invention is not limited to the embodiments disclosed above, but also includes various modifications and equivalents which fall within the scope of the following claims.

Claims (6)

A switch for sequentially selecting a reception path of each sector according to a switching command and for introducing a frequency signal through the path; A first phase synchronizing loop synthesizer which sequentially oscillates the center frequency and the left and right frequencies of the filter according to a frequency command and provides the switch to the switch; A level detector for detecting a DC level of a signal fed back from a reception path of each sector and outputting the detected level; Generating and outputting a switching command for the switch to sequentially select each sector, controlling the first phase-synchronizer loop synthesizer to oscillate the frequencies, and storing the DC level output from the level detector in advance. A control board comprising a microprocessor that outputs a switching command that causes the bypass path in the duplexer module to be selected when there is a level change compared to the state level, and outputs a warning command to the base station system; Tower tower low noise amplifier. The method of claim 1, wherein the control board A second phase synchronizer loop synthesizer for oscillating an intermediate frequency under the control of the microprocessor; And And a mixer for mixing the intermediate frequency oscillated in the second phase synchronizer loop synthesizer with the feedback signal and outputting the mixed signal to the level detector. Tower tower low noise amplifier. A plurality of duplexer modules having a transmission path and a reception path connected to the antenna, and a reception filter is installed on the reception path, the line bypassing the reception path, and a switch for selecting the plurality of duplexers; A tower top low noise amplifier connected between the receive filters of the duplexer module to form a receive path; A base station system connected to a transmission / reception path of the duplexer module; And Generates a frequency signal for checking the state of the receiving filter and the tower top low noise amplifier in the duplexer module and outputs the frequency signal sequentially to the duplexer module, and detects the DC level of the signal fed back from the receiving path in the duplexer module, And a control board for comparing the determined level with a level in a steady state to determine a filter characteristic change and reporting the result to the base station system. The method of claim 3, wherein the control board is A switch for sequentially selecting a reception path of the plurality of duplexer modules according to a switching command and for introducing a frequency signal through the path; A first phase synchronizer loop synthesizer which sequentially oscillates the center frequency and the left and right frequencies of the reception filter according to a frequency command and provides the switch to the switch; A level detector for detecting a DC level of a signal fed back from a reception path of each duplexer module and outputting the detected level; Generating and outputting a switching command for the switch to sequentially select each sector, controlling the first phase-synchronizer loop synthesizer to oscillate the frequencies, and storing the DC level output from the level detector in advance. And a microprocessor for outputting a switching command for outputting a switching command for selecting a bypass path in the duplexer module when there is a level change compared to a state level. Base station device. The method of claim 4, wherein the control board A second phase synchronizer loop synthesizer for oscillating an intermediate frequency under the control of the microprocessor; And And a mixer for mixing the intermediate frequency oscillated in the second phase synchronizer loop synthesizer with the feedback signal and outputting the mixed signal to the level detector. Base station device. For all sectors, a first step of oscillating the predetermined intermediate frequency and the left and right frequencies of the reception filter, and correspondingly storing the DC level of the fed back signal as a steady state level; According to a check instruction of the base station system, oscillates the predetermined intermediate frequency and the left and right frequencies of the reception filter for all sectors, and correspondingly compares the DC level of the fed back signal with the steady state level stored in the first step, A second step of reporting the comparison result to a base station system; And a third step of controlling a bypass switch to select a bypass line in the duplexer module when the DC level of the signal fed back in the second step is different from the steady state level, and outputting a warning command to the base station system. The control method of the tower tower low noise amplifier.

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