KR101973669B1 - Apparatus and method to remove PIM for mobile telecommunications system - Google Patents

Abstract

The present invention relates to an apparatus for removing a PIM generated by combining signals of a plurality of bands in a mobile communication system that efficiently combines a plurality of band signals into one signal and transmits the same.
An apparatus for removing a PIM in a mobile communication system according to the present invention includes a band combiner 410 for receiving forward signals of a plurality of bands and combining signals of respective bands; A combiner 430 for transmitting the band combiner forward signal received from the band combiner to the antenna and receiving a reverse signal from the antenna; And combines each band signal of the band combiner to generate an interference cancellation signal. The generated interference cancellation signal is combined with an interference signal input to an inverse signal received from the combiner 430, And an interference signal removing unit 420 for removing an interference signal.

Description

[0001] The present invention relates to an apparatus, a method, and a mobile communication system for removing a PIM in a mobile communication system,

The present invention relates to an apparatus and method for removing PIM (Passive Intermodulation) in a mobile communication system, and more particularly, to an apparatus and method for removing PIM (PIM) To an apparatus and method for removing a PIM in a mobile communication system.

In general, mobile operators establish a mobile communication network that can provide high quality wireless quality anywhere in the service coverage. However, even if a plurality of terrestrial optical repeaters or base stations are installed by a mobile communication provider, a shaded area where radio waves are not attained occurs in some mobile communication networks. Especially, since the antennas of the terrestrial optical repeater and the base station tend to be oriented toward the road, there is a high probability that the interior of the high-rise building will be a shaded area of radio waves. This is because the building is high and it is difficult for the radio waves to penetrate easily through the outer wall of the building.

Since a mobile communication company generally provides a plurality of mobile communication services (for example, cellular, PCS, WCDMA, WIBRO, TRS, etc.) rather than providing one mobile communication service, Shaded areas occur. In order to solve such a shadow area, it is necessary to install a feeder line and an antenna for each service. At this time, more installation cost is required than the installation cost of an in-building repeater necessary for a mobile communication service in a building.

Accordingly, a mobile communication service provider providing at least two or more mobile communication services has made various efforts to reduce the cost of laying a feeder line and secure service coverage in a shade building. Among them, there is a method of sharing a feeder line by using a feeder router in a typical method. Since the two mobile communication services use different frequency bands (ie, 2.1 GHz for WCDMA and 1.8 GHz for PCS), the cost of laying the feeder line can be reduced by half using a feeder router that combines filter characteristics of the corresponding frequency band have. However, there should be no IM (Intermodulation) interference at this time.

When a PIM signal is generated and processed in a single device, the PIM signal is generated and reflected in the input direction. If the PIM signal is generated due to the passage of time and the change of the environment, have.

According to the related art related to the PIM signal, the PIM signal monitoring system of Korean Patent Registration No. 0820165 and the PIM signal monitoring method using the same are proposed.

The PIM signal monitoring system includes a WCDMA transmission line, a WCDMA repeater, a WiBro transmission line, and a WiBro repeater. The mobile communication system is connected to the WCDMA transmission line to transmit / receive signals to / from an external antenna, A first duplex; A second duplexer connected to the WCDMA repeater for transmitting and receiving signals to and from the WCDMA repeater, and for branching the received and received signals; A low noise amplifier for amplifying a received signal branched in the first duplex; A divider for branching the amplified signal from the low noise amplifier; A receiving power detector for detecting an RF signal level of a signal branched by the distributor; A signal extractor for extracting a transmission frequency signal of a WiBro band generated by the WiBro transmission line and a WiBro repeater; A transmit power detector for detecting an RF signal level of a signal extracted from the signal extractor; And a PIM signal controller for determining whether to generate a PIM signal by comparing, determining and analyzing an RF signal level detected by the reception power detector and the transmission power detector.

In the mobile communication system, various frequency bands are used. If multiple frequencies are used, multiple antenna facilities will be installed. If one antenna is used, it is possible to reduce the facility cost or to operate it easily. However, when one antenna is used, PIM (Passive Intermodulation) occurs due to coupling with another frequency, have.

1, the basic structure of a conventional mobile communication relay system includes a base station 10, a host unit 20, a remote unit 30, and a combiner 40.

In such a mobile communication system, when a plurality of frequency bands are input, a separate apparatus configuration is required for each band as shown in FIG. 2, which leads to problems such as a cost and an increase in the volume of the apparatus configuration.

In order to solve such a problem, as shown in FIG. 3, when designing a device configuration for processing a plurality of frequency bands together, when a plurality of bands are processed at the same time, The interference signal (PIM) component generated by the interference signal (PIM) is generated, and a part of the interference signal may have a frequency included in the reverse frequency band, which may adversely affect the quality of the reverse signal.

As shown in FIG. 5, when an interference signal having a frequency similar to a reverse frequency is input to a reverse signal, there is a problem that distortion occurs due to an interference signal in an inverse signal.

Accordingly, it is an object of the present invention to provide an apparatus and method for eliminating interference occurring when a plurality of frequencies are simultaneously processed in a mobile communication system.

According to an aspect of the present invention, there is provided an apparatus for removing a PIM in a mobile communication system, comprising: a band combiner for receiving forward signals of a plurality of bands and combining signals of the bands; A combiner 430 for transmitting the band combiner forward signal received from the band combiner to the antenna and receiving a reverse signal from the antenna; And combines each band signal of the band combiner to generate an interference cancellation signal. The generated interference cancellation signal is combined with an interference signal input to an inverse signal received from the combiner 430, And an interference signal removing unit 420 for removing the interference signal.

Here, the apparatus may further include a band splitter 450 for separating the reverse signal from which the interference signal is removed, for each frequency band.

The interference signal removing unit 420 detects an interference signal generated due to the combination of the band signals of the band combiner and generates a signal for canceling an interference signal by adjusting the magnitude and / or phase of the detected interference signal , And the generated interference signal cancellation signal can be combined with the interference signal introduced into the reverse signal to remove the interference signal.

The interference canceller 420 includes a detector 421 for detecting an interference signal generated due to the combination of the band signals of the band combiner, A signal generator 422 for adjusting the magnitude and / or phase of the detected interference signal to generate a signal for removing an interference signal; And a signal combining unit 424 for combining the generated interference signal removing signal with the interference signal introduced into the reverse signal to remove the interference signal.

The interference signal removing unit 420 includes an interference signal adjusting unit 423 for adjusting the magnitude and / or phase of the interference signal introduced into the reverse signal through the combiner 430 to assist in eliminating the interference signal .

A mobile communication system having a PIM removal function according to the present invention includes a host unit 200 for receiving forward signals of a plurality of frequency bands and transmitting the forward signals to a remote unit 300; A remote unit 300 for receiving the forward signals of the plurality of frequency bands from the host unit 200 and transmitting the forward signals to the combiner unit 400; And the forward signal received through the remote unit 300 is coupled to the antenna, and the reverse signal received from the antenna is transmitted to the remote unit. The interference signal generated due to the combination of the forward signals of the plurality of bands is transmitted to the reverse unit And a coupler unit 400 having an interference signal canceling function for preventing incoming and transmitted signals.

The coupler unit 400 includes a band combiner 410 for receiving forward signals of a plurality of bands and combining signals of the bands; A combiner 430 for transmitting the band combiner forward signal received from the band combiner to the antenna and receiving a reverse signal from the antenna; And combines each band signal of the band combiner to generate an interference cancellation signal. The generated interference cancellation signal is combined with an interference signal input to an inverse signal received from the combiner 430, And an interference signal removing unit 420 for removing the interference signal.

The interference canceller 420 includes a detector 421 for detecting an interference signal generated due to the combination of the band signals of the band combiner, A signal generator 422 for adjusting the magnitude and / or phase of the detected interference signal to generate a signal for removing an interference signal; And a signal combining unit 424 for combining the generated interference signal removing signal with the interference signal introduced into the reverse signal to remove the interference signal.

The interference signal removing unit 420 includes an interference signal adjusting unit 423 for adjusting the magnitude and / or phase of the interference signal introduced into the reverse signal through the combiner 430 to assist in eliminating the interference signal .

The system may further include a band splitter 450 for separating the reverse signal from which the interference signal is removed, for each frequency band.

A method for removing a PIM in a mobile communication system according to the present invention includes:

(a) receiving forward signals of a plurality of bands and combining signals of the respective bands; (b) detecting an interference signal generated due to combination of forward signals of a plurality of bands, and converting a magnitude and / or a phase of the detected interference signal to generate a signal for removing an interference signal; And (c) receiving a reverse signal from the antenna, and combining the generated interference signal cancellation signal and the reverse signal to eliminate the interference signal introduced into the reverse signal.

The method may further include: (d) a band separating step of separating the reverse signal from which the interference signal is removed for each frequency band.

The step (c) may adjust the magnitude and / or phase of the interference signal introduced into the reverse signal so as to facilitate the removal of the interference signal and then combine the signal with the interference signal removal signal.

As described above, the apparatus, the method, and the mobile communication system for removing the PIM according to the present invention remove interference signals generated when forward signals of different bands are combined when signals of various frequency bands are simultaneously processed Thereby solving the problem caused by the characteristics of the reverse-directional signal, and combining and combining various frequencies.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exemplary view showing a basic structure of a conventional mobile communication system; FIG.
Fig. 2 is an exemplary diagram for explaining a case where a plurality of frequency bands are input. Fig.
3 is an exemplary view showing a configuration for processing a plurality of bands together;
4 is a diagram for explaining a problem that occurs when a plurality of bands are processed at the same time.
5 shows a block diagram of a combiner unit before interference cancellation;
6 is an overall configuration diagram of a mobile communication system according to the present invention;
7 and 8 are block diagrams of a combiner unit of a mobile communication system according to the present invention.

Hereinafter, the present invention will be described in detail with reference to exemplary drawings attached hereto.

FIG. 6 is an overall configuration diagram of a mobile communication system according to the present invention, and FIGS. 7 and 8 are block diagrams of a combiner unit of a mobile communication system according to the present invention.

6, a system for removing an interference signal (PIM) in a mobile communication system according to the present invention includes a plurality of base stations 100, a host unit 200, a remote unit 300, (400).

For convenience, the first base station # 1 and the second base station # 2 will be described in this embodiment.

The host unit 200 -

The host unit 200 includes a forward signal processor 211 for receiving and processing a plurality of band-specific forward RF signals from a signal source such as the base station 100, and a reverse RF signal receiver And a first signal transmission unit 220 for transmitting a forward RF signal of the forward signal processing unit 211 to a remote unit, and a second signal transmission unit 220 for transmitting a forward RF signal of the forward signal processing unit 211 to a remote unit, ).

Here, the forward signal processing unit 211 of the host unit signal processor 210 may perform signal processing functions such as digital conversion, frequency down conversion, amplification, attenuation, gain adjustment, and the like, And performs a function of transmitting and receiving a signal processed through the signal processing unit 211 through a connection means such as an optical fiber or a coaxial cable.

For reference, in the present embodiment, a case where a forward RF signal from a base station or the like is transmitted to a remote unit will be described as an example, and a description of a case where a reverse RF signal of a remote unit is transmitted to the host unit will be omitted.

In addition, the host unit signal processor 210 may include a processor unit 213 for monitoring an input level of a forward RF signal. The processor unit unit 213 is provided with an RS-232C port for serial communication to enable the status and control of the equipment through a computer. The processor unit unit 213 may include a communication LED indicator for confirming a communication state with the remote unit 300 on the front panel and an alarm LED indicator Indicator). An Ethernet port and a port for mounting a GSM modem may be provided for accessing the upper network.

Remote unit 300 -

The remote unit 300 performs a function of receiving and processing the forward signal transmitted from the first transmission means 220 of the host unit 200. The remote unit 300 includes a second transmitting means 310 for receiving and transmitting a forward signal from a link means such as an optical fiber, a remote unit forward signal processing unit 321 for processing a forward signal transmitted from the second transmitting means 310 And a remote unit signal processor 322 that processes a reverse signal received from the combinator unit 400. The remote unit signal processor 322 includes a remote unit signal processor 322,

The second transmitting unit 310 receives a signal transmitted from the first transmitting unit of the host unit 200 through the link unit and transmits the signal to the remote unit signal processor. If the link means is an optical fiber, it may include an optical / electrical conversion function.

The remote unit forward signal processing unit 321 can perform necessary signal processing functions such as analog conversion, frequency up conversion, amplification, attenuation, gain adjustment, and the like, and includes a band pass filter (BPF) It is possible to perform signal processing for driving the antenna.

And the remote unit 300 may include a remote central processor unit (RCPU) The remote central processor unit 323 of the remote unit 300 can monitor the status of the second transmission means 310 and control the remote unit 300 and includes an LED indicator Or it can be judged whether or not it is abnormal at a time. And it can include communication LED indicator on the front, so you can check the communication status with the upper level, and check and control the status of the equipment through PC etc. through RS-232C serial port.

The forward signals of the plurality of bands input to the remote unit signal processor 320 through the second transmission unit 310 are band-filtered while passing through the band-pass filter in the remote unit forward signal processing unit 321, Amp and is transmitted to the antenna through the coupler unit 400. The reverse signal received through the coupler unit 400 is filtered and amplified by the remote unit reverse signal processor 322 and transmitted to the second transmission unit do.

Here, in the present embodiment, the optical fiber or the coaxial cable is exemplified as the link means for connecting the host unit 200 and the remote unit 300, but other link means may be used, and signal conversion or the like suitable for each link means It is needless to say that the first and second transmission means can be configured to perform the function.

Coupler unit 400 -

The coupler unit 400 performs a function of transmitting a forward signal and a receiving function of a reverse signal, and in doing so, performs a function of removing an interference signal generated at the time of simultaneous processing of a plurality of band signals.

The combiner unit 400 for performing such a function may include a band combiner 410, an interference signal removing unit 420, a combiner 430, and a band splitter 450, as shown in FIG.

The combiner unit 400 includes a band combiner 410 for combining forward signals of a plurality of frequency bands received from the remote unit 300 and a combiner 410 for detecting an interference signal PIM generated by combining the respective band signals of the combiner And generates an interference signal removing signal by adjusting the phase and / or size of the detected interference signal to remove the interference signal flowing into the reverse signal, combines the generated interference signal removing signal and the reverse signal, A combiner 430 for transmitting a forward signal and a reverse signal, and a band splitter 450 for separating the reverse signal into signals of respective frequency bands, ).

The interference signal cancellation unit 420 includes a detection unit 421, a signal generation unit 422, and a signal generation unit 424 for generating an interference cancellation signal for canceling interference signals generated due to coupling of various band signals of the band combiner. And a signal synthesizing unit 424.

The detection unit 421 detects an interference signal generated due to the combination of various band signals of the band combiner. For example, the detecting unit 421 can detect an interference signal included in the forward signal without affecting the flow of the forward signal by using a coupler or the like.

The signal generating unit 422 performs a function of adjusting the magnitude and / or phase of the interference signal detected through the detecting unit to generate a signal for removing the interference signal.

The signal combining unit 424 combines the interference signal removing signal output from the signal generating unit 422 and the reverse signal received from the combiner to cancel the interference signal included in the reverse signal and remove the interference signal .

The band splitter 450 separates the reverse signals output from the signal combiner 424 by band.

Modified embodiment of the interference signal removing unit 420:

8 shows a modified embodiment of the interference canceller. As shown in FIG. 8, the detecting unit 421 detects an interference signal generated due to a combination of forward signals of a plurality of frequency bands.

The signal generator 422 performs a function of selectively performing a phase transformation, a size adjustment, a time delay, and the like on the interference signal detected through the detector 421 to generate a signal for canceling an interference signal.

The interference signal adjusting unit 423 performs a function of assisting the signal generating unit 422 to convert the magnitude and / or phase of the interference signal introduced into the reverse signal to facilitate the removal of the interference signal.

The interference signal that has passed through the interference signal adjusting unit and the interference signal removing signal of the signal generating unit have a phase difference of 180 degrees so that they are canceled each other by the signal combining unit 424 and removed. In this case, when the interference signal detected by the detection unit 421 is transformed in size and / or phase using only the signal generation unit 422, it is difficult to completely remove the interference signal flowing into the reverse signal, The adjusting unit 423 has an effect of facilitating the removal of the interference signal by adjusting the magnitude and / or phase of the interference signal introduced into the reverse signal.

As described above, the present invention has an effect of effectively removing an interference signal (PIM) generated due to a combination of frequencies in a mobile communication system that combines and transmits a plurality of band signals into one signal.

100: base station 200: host unit
210: Host unit signal processor 211: Forward signal processor
212: reverse signal processing unit 213: processor unit unit
220: first transmission means 300: remote unit
310: second transmission means 320: remote unit signal processor
321: remote unit forward signal processing unit 322: remote unit reverse direction signal processing unit
323: remote central processor unit 400: combiner unit
410: Band combiner 420: Interference signal cancellation
421: Detecting section 422:
423: Interference signal control unit 424: Signal synthesis unit
430: combiner 450: band splitter

Claims (13)

1. An apparatus for removing a PIM in a mobile communication system,
A band combiner 410 for receiving forward signals of a plurality of bands and combining signals of respective bands;
A combiner 430 for transmitting the band combiner forward signal received from the band combiner to the antenna and receiving a reverse signal from the antenna;
A signal for removing the interference signal generated due to the combination of the band signals of the band combiner is generated, and a signal for removing the generated interference signal is generated by combining the interference signal inputted into the reverse signal received from the combiner 430 An interference signal removing unit 420 for combining and removing an interference signal; And
And a band splitter (450) for separating the reverse signal from which the interference signal has been removed for each frequency band. delete The method according to claim 1,
The interference signal cancellation unit 420,
An interference signal generated due to coupling of each band signal of the band combiner is detected and an interference signal cancellation signal is generated by adjusting the size and / or phase of the detected interference signal, Wherein the interference signal is combined with an interference signal introduced into the signal to remove the interference signal. The method according to claim 1,
The interference signal cancellation unit 420,
A detector (421) for detecting an interference signal generated due to coupling of each band signal of the band combiner;
A signal generator 422 for adjusting the magnitude and / or phase of the detected interference signal to generate a signal for removing an interference signal; And
And a signal combining unit (424) for combining the generated interference signal removing signal with an interference signal input to the reverse signal to remove the interference signal. 5. The method of claim 4,
The interference signal cancellation unit 420,
And an interference signal controller (423) for adjusting the magnitude and / or phase of the interference signal introduced into the reverse signal through the combiner (430) to assist in removing the interference signal. To remove the PIM from the device.
In a mobile communication system having a PIM removal function,
A host unit (200) for receiving forward signals of a plurality of frequency bands and transmitting the forward signals to a remote unit (300);
A remote unit 300 for receiving the forward signals of the plurality of frequency bands from the host unit 200 and transmitting the forward signals to the combiner unit 400; And
The remote unit 300 combines the forward signals received through the remote unit 300 and transmits the forward signals to the antenna. The reverse signals received from the antennas are transmitted to the remote units. The interference signals generated by the combination of the forward signals of the plurality of bands are input to the reverse signals And a combiner unit (400) having an interference signal removing function for preventing transmission of interference signals,
The coupler unit 400 includes a band combiner 410 for receiving forward signals of a plurality of frequency bands and combining signals of respective bands; A combiner 430 for transmitting the band combiner forward signal received from the band combiner to the antenna and receiving a reverse signal from the antenna; A signal for removing the interference signal generated due to the combination of the band signals of the band combiner is generated, and a signal for removing the generated interference signal is generated by combining the interference signal inputted into the reverse signal received from the combiner 430 An interference signal removing unit 420 for combining and removing an interference signal; And a band splitter (450) for separating the reverse signal from which the interference signal has been removed for each frequency band. delete The method according to claim 6,
The interference signal cancellation unit 420,
A detector (421) for detecting an interference signal generated due to coupling of each band signal of the band combiner;
A signal generator 422 for adjusting the magnitude and / or phase of the detected interference signal to generate a signal for removing an interference signal; And
And a signal combining unit (424) for combining the generated interference signal removing signal with an interference signal input to the reverse signal to remove the interference signal. 9. The method of claim 8,
The interference signal cancellation unit 420,
And an interference signal controller (423) for adjusting the magnitude and / or phase of the interference signal introduced into the reverse signal through the combiner (430) to assist in removing the interference signal. . delete A method for removing a PIM in a mobile communication system,
(a) receiving forward signals of a plurality of bands and combining signals of the respective bands;
(b) detecting an interference signal generated due to combination of forward signals of a plurality of bands, and converting a magnitude and / or a phase of the detected interference signal to generate a signal for removing an interference signal;
(c) receiving a reverse signal from the antenna, and combining the generated interference signal cancellation signal and the reverse signal to remove the interference signal introduced into the reverse signal; And
(d) separating the reverse signal from which the interference signal has been removed for each frequency band. delete 12. The method of claim 11,
The step (c)
A method for removing a PIM in a mobile communication system, the method comprising: adjusting a magnitude and / or a phase of the interference signal introduced into a reverse signal so as to facilitate removal of an interference signal; .

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