KR101415753B1 - Repeater and Repeating Method for Mobile Communication System - Google Patents

Abstract

The present invention relates to a super heterodyne RF repeater and a repeating method thereof for using a normal cyclic prefix (CP) 4.7 usec as much as possible in a long term evolution (LTE) orthogonal frequency division multiple access (OFDMA) mobile communications system. In a repeater for amplification of a super heterodyne method, the repeater of a mobile communication system according to an aspect of the present invention comprises: a frequency down converter for converting a received high frequency signal into an intermediate frequency signal; an IF filter for performing filtering to obtain a desired intermediate frequency signal from the converted intermediate frequency signal; and a frequency up converter for converting the intermediate frequency signal outputted from the IF filter into a high frequency signal. The frequency down converter converts the high frequency signal into an intermediate frequency signal equal to or above 500 MHz and then outputs the converted signal, and the IF filter may comprise a filter having delay equal to or less than 1 usec.

Description

TECHNICAL FIELD [0001] The present invention relates to a repeater and a repeating method for a mobile communication system,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates generally to a relay apparatus and method for a mobile communication system, and more particularly to a mobile communication system using an LTE (Long Term Evolution) OFDMA (Orthogonal Frequency Division Multiple Access) To a superheterodyne RF repeater and a relay method for maximizing the use of a normal CP (Cyclic Prefix) of 4.7 usec in a mobile communication system.

Mobile communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Such multiple access systems may include, for example, a Code Division Multiple Access (CDMA) system, a Time Division Multiple Access (TDMA) system, a Frequency Division Multiple Access (FDMA) system, a 3GPP Long Term to LTE system, (OFDMA) system, and the like.

Generally, a wireless multiple access communication system can simultaneously support communication for a plurality of wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward link and the reverse link. The forward link (or downlink or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (also referred to as the uplink or uplink) refers to the communication link from the terminals to the base stations do. Such a communication link may be established through a single input single output (SISO) scheme, a multiple input single output (MISO) scheme, or a multiple input multiple output (MIMO) scheme.

On the other hand, in the above-described various types of mobile communication systems, it is necessary to construct a repeater in a region where the installation cost of the base station is covered or the area is covered with radio wave shading. Generally, a superheterodyne type RF repeater is used. Heterodyne RF repeaters use an intermediate frequency (IF) SAW filter with a high Q value for selectivity, sensitivity, and image frequency rejection, so the basic delay of the SAW filter (about 1.5 between uS and 2.5uS) is reflected in the equipment.

That is, in the superheterodyne method, the selectivity, sensitivity, and image frequency can be easily removed. In order to use a general SAW filter band, an intermediate frequency is used at 500 MHz or less. Such a SAW filter basically generates a delay, ) Causes a delay time of approximately 1.5 to 2.5 us.

As described above, since the conventional RF repeater satisfies the selectivity and sensitivity characteristics and uses the SAW filter to effectively remove the image frequency, basically, the delay of the other device is added in addition to the delay caused by the SAW filter, ~ 3us of equipment delay.

However, there is a problem in using the high power RF repeater within the normal CP (about 4.7 uS) of the OFDMA due to the equipment delay described above.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the related art, and it is an object of the present invention to provide an apparatus and a method for minimizing equipment delay caused by an RF repeater of a mobile communication system such as an LTE OFDMA system, And to provide a relay apparatus and method of a mobile communication system that can be used as much as possible.

According to one aspect of the present invention, there is provided a relay apparatus for amplifying a superheterodyne system, the relay apparatus comprising: a frequency converter for converting a received high frequency signal into an intermediate frequency signal, Down converter; An IF filter that performs filtering to obtain a desired intermediate frequency band signal in the converted intermediate frequency band signal; And a frequency up converter for converting an intermediate frequency band signal output from the IF filter into a high frequency band signal, wherein the frequency down converter converts the high frequency band signal into an intermediate frequency band signal having a frequency of 500 MHz or more, And the IF filter may be composed of a filter having a delay of 1 usec or less.

The IF filter may include at least one of a cavity filter, a DR-Cavity filter, a DR (Dielectric Resonator) filter, a FBAR (Film Bulk Acoustic Resonator) filter, and a RF SAW It can be composed of one.

The frequency down converter, the IF filter, and the frequency up converter may be installed on at least one of a forward signal path and a reverse path.

According to one aspect of the present invention, there is provided a method of relaying a mobile communication signal, the method comprising the steps of: (a) receiving a signal of a high frequency band as a signal of an intermediate frequency band; Converting; (b) performing filtering to obtain a desired intermediate frequency band signal in the converted intermediate frequency band signal; And (c) converting the filtered intermediate frequency band signal into a high frequency band signal and outputting the signal, wherein the step (a) converts the high frequency band signal into an intermediate frequency band signal having a frequency of 500 MHz or more In step (b), filtering may be performed using an IF filter having a delay of 1 usec or less.

In the IF filtering in step (b), a cavity filter, a DR-Cavity filter, a DR filter, a film bulk acoustic resonator (FBAR) filter, and a surface acoustic wave (SAW) Wave filter can be used as an IF filter.

The step (a), the step (b), and the step (c) may be performed on the forward signal path as an example, or on another signal path on the reverse signal path as another example, or on both the forward signal path and the reverse signal path Can be performed.

As described above, according to various aspects of the present invention, since the forward / reverse intermediate frequency (IF) band of the OFDMA type RF repeater is raised to 500 MHz or more, an IF filter for selectivity, sensitivity characteristic, Cavity filters, DR (dielectric resonator) filters, FBAR (Film Bulk Acoustic Resonator) filters, or RF SAWs (Surface Acoustic Wave ) Filter, and the use of an IF filter having a very small delay results in minimizing the equipment delay.

In addition, by minimizing equipment delay, restriction of use of RF repeater due to restriction of normal CP (about 4.7 uS) in OFDMA scheme is solved, and utilization of high power RF repeater is improved to improve service quality.

1 is a configuration diagram of a relay apparatus of a mobile communication system according to an embodiment of the present invention;
FIG. 2 is a detailed configuration diagram of the downstream signal amplifying unit of FIG. 1,
FIG. 3 is a detailed configuration diagram of the upstream signal amplifying unit of FIG. 1,
4 is a flowchart of a mobile communication signal relaying method according to an embodiment of the present invention,
5 is an exemplary diagram for comparing a service distance of the relay apparatus of FIG. 1 with a conventional relay apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals are used to denote like elements in the drawings, even if they are shown in different drawings. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

1, duplexers 121 and 122, a downlink signal amplifying unit 130, and an uplink signal amplifying unit 150, as shown in the figure, are configured as a relay apparatus of a mobile communication system according to an embodiment of the present invention. .

The duplexer 121 is connected to a donor antenna 111 which is opposite to a base station (not shown) and transmits a downward (or forward) signal received through the donor antenna 111 and an upward (or backward) The downlink signal received from the donor antenna 111 is output to the downstream signal amplifying unit 130 and the upstream signal input from the upstream signal amplifying unit 150 is output to the donor antenna 111. [ To the base station side.

The duplexer 122 is connected to a service antenna 112 opposed to a user terminal (not shown) and separates an upstream signal and a transmitted downstream signal received through the service antenna 112 from each other. For example, The uplink signal received from the service antenna 112 is output to the upstream signal amplifying unit 150 and the downlink signal input from the downstream signal amplifying unit 130 is transmitted to the user terminal through the service antenna 112.

The downlink signal amplifying unit 130 amplifies the downlink signal input from the duplexer 121 and outputs the downlink signal to the duplexer 122. For example, the downlink signal amplifying unit 130 may be configured with a superheterodyne type amplifier structure, The frequency down-converter (refer to 131 in FIG. 2) in the dyne-type amplifier structure converts the downstream signal of the input high frequency band into a downstream signal of the intermediate frequency band having a frequency of 500 MHz or more, An IF filter (see 130e in FIG. 2) that performs filtering to obtain a desired intermediate frequency band signal from a downstream signal of the frequency band is composed of a filter having a delay of 1usec or less.

The upstream signal amplifying unit 150 amplifies the downstream signal inputted from the duplexer 122 and outputs the amplified downstream signal to the duplexer 121. For example, the upstream signal amplifying unit 150 may have a superheterodyne type amplifier structure, The frequency down converter (refer to 151 in FIG. 3) in the dyne type amplifier structure converts an upstream signal of the input high frequency band into an upstream signal of an intermediate frequency band having a frequency of 500 MHz or more and outputs the upstream signal, An IF filter (see 150e in FIG. 3) that performs filtering to obtain a signal of a desired intermediate frequency band from a downstream signal of the intermediate frequency band is composed of a filter having a delay of 1usec or less.

Since the conventional superheterodyne amplifier uses a SAW filter in order to facilitate selection, sensitivity, and removal of image frequency, it is necessary that the upper / lower intermediate frequency is set to 500 MHz or less However, according to the present embodiment, since the upper / lower intermediate frequency is higher than 500 MHz (preferably 1 GHz or more), the selectivity and sensitivity characteristics are satisfied and the image frequency is effectively removed. Significantly less, that is, a filter having a delay of 1 usec or less or 0.5 usec or less can be used.

Therefore, according to the above-described embodiment, it is possible to make an RF repeater in which the equipment delay is significantly smaller than that of the conventional OFDMA system, and the limitation of the use of the RF repeater due to the restriction of the normal CP (about 4.7 uS) And it is possible to expand the service area of high quality by increasing the utilization of the high power RF repeater.

2 shows an example of a detailed configuration of the downlink signal amplifying unit 130 of FIG. 1. As shown in FIG. 2, the downlink signal amplifying unit 130 includes an amplifier 130a, a local oscillator 130b, and a mixer 130c A frequency up-converter 133, an amplifier 130j, and a mixer 130i including a frequency down-converter 131, an amplifier 130d, an IF filter 130e, amplifiers 130f and 130g, a local oscillator 130h, The RF filter 130k, the amplifier 1301, the variable attenuator 130m and the amplifier 130n may be configured in the same or similar structure as that of a general superheterodyne type amplifier connected in series, It is omitted.

According to the present embodiment, the frequency down-converter 131 converts the input down-signal of the high-frequency band into a down-signal of the intermediate frequency band having a frequency of 500 MHz or higher and outputs the down- A filter having a delay of 1usec or less can be configured to perform filtering to obtain a desired intermediate frequency band signal from the signal.

In this embodiment, the IF filter 130e includes a cavity filter, a DR-Cavity filter, a DR filter, a film bulk acoustic resonator (FBAR) filter having a delay of about 1 microseconds or less or about 0.5 microseconds or less, A resonator, and a high frequency (SAW) filter.

3 shows an example of a detailed configuration of the upstream signal amplifying unit 150 of FIG. 1. As shown in FIG. 3, the upstream signal amplifying unit 150 includes an amplifier 150a, a local oscillator 150b, and a mixer 150c A frequency up-converter 153 including the frequency down-converter 151, the amplifier 150d, the IF filter 150e, the amplifiers 150f and 150g, the local oscillator 150h and the mixer 150i, the amplifier 150j, The RF filter 150k, the amplifier 1501, the variable attenuator 150m and the amplifier 150n may be configured in the same or similar structure as that of a general superheterodyne type amplifier connected in series, It is omitted.

According to the present embodiment, the frequency down-converter 151 converts an input upstream signal of the high frequency band into an upstream signal of an intermediate frequency band having a frequency of 500 MHz or more, and outputs the upstream signal, and the IF filter 150e, A filter may be constructed to obtain a signal of a desired intermediate frequency band in a signal, and a filter having a delay of about 1 microseconds or less.

In this embodiment, the IF filter 150e includes a cavity filter, a DR-Cavity filter, a DR filter, a film bulk acoustic resonator (FBAR) filter having a delay of about 1 microsecond or less or about 0.5 microseconds or less, Resonator filter, and a high frequency (RF) SAW (surface acoustic wave) filter.

FIG. 4 is a flowchart of a method of relaying a mobile communication signal according to an embodiment of the present invention, and is applied to the relay apparatus 100 of FIG. 1 and will be described in parallel with the operation of the relay apparatus 100, Described by route.

Forward path

First, a relaying method for a downlink signal on a forward path in an OFDMA system will be described.

When the OFDMA RF signal as a forward (or downward) high frequency band signal is received via the donor antenna 111, the received forward OFDMA RF signal is input to the downstream signal amplifying unit 130 through the duplexer 121 (S401).

The downstream signal amplifying unit 130 converts the forward OFDMA RF signal input from the duplexer 121 into an OFDMA IF signal as an intermediate frequency band signal through a frequency down-converter (refer to 131 in FIG. 2), and in particular, Into an OFDMA IF signal as an intermediate frequency band signal (S402).

Next, the downlink signal amplifying unit 130 performs filtering using an IF filter (see 131e in FIG. 2) to obtain a desired intermediate frequency band signal in the OFDMA IF signal having a frequency of 500 MHz or more converted through step S402 In particular, in the present embodiment, the above-described IF filter is an IF filter having a delay of 1 μsec or less, such as a cavity filter, a DR-Cavity filter, a DR (Dielectric Resonator) filter, a FBAR (Film Bulk Acoustic Resonator) Filter, and a high-frequency (RF) surface acoustic wave (SAW) filter (S403).

Next, the downstream signal amplifying unit 130 converts the intermediate frequency band signal filtered in step S403 into an OFDMA RF signal of a high frequency band through a frequency up converter (refer to 133 in FIG. 2), and thereafter performs amplification, RF filtering, , Power amplification, and the like, and provides the input to the duplexer 122 (S404).

Finally, in step S404, the OFDMA RF signal of the high frequency band outputted from the downlink signal amplifying unit 130 is separated into a downward path through the duplexer 122 and transmitted to the user terminal (not shown) through the service antenna 112 (S405).

Reverse path

Next, a method for relaying uplink signals on the reverse path in the OFDMA system will be described.

When the OFDMA RF signal is received as a signal in the reverse (or upward) high frequency band through the service antenna 112, the received forward OFDMA RF signal is input through the duplexer 122 to the input of the upstream signal amplifying unit 150 (S501).

The upstream signal amplifying unit 150 converts the reverse OFDMA RF signal input from the duplexer 122 into an OFDMA IF signal as an intermediate frequency signal through a frequency down-converter (refer to 151 in FIG. 3), and in particular, Into an OFDMA IF signal as an intermediate frequency band signal (S502).

Next, the upstream signal amplifying unit 150 performs filtering using an IF filter (see 151e in FIG. 3) to obtain a desired intermediate frequency band signal in the OFDMA IF signal having a frequency of 500 MHz or more converted in step S502 In particular, in the present embodiment, the above-described IF filter is an IF filter having a delay of 1 μsec or less, such as a cavity filter, a DR-Cavity filter, a DR (Dielectric Resonator) filter, a FBAR (Film Bulk Acoustic Resonator) Filter, and a high-frequency (RF) surface acoustic wave (SAW) filter (S503).

Next, the upstream signal amplifying unit 150 converts the intermediate frequency band signal filtered in step S503 into an OFDMA RF signal of a high frequency band through a frequency up converter (refer to 153 in FIG. 3), and then performs amplification, RF filtering, , Power amplification, and the like, and provides it as an input of the duplex 121 (S504).

Finally, in step S504, the OFDMA RF signal of the high frequency band outputted from the upstream signal amplifying unit 150 is separated into an upward path through the duplexer 121 and transmitted to the base station (not shown) through the donor antenna 111 S505).

 FIG. 5 is an exemplary diagram for comparing the service distance of the relay apparatus 100 of FIG. 1 and the existing relay apparatus 200.

5 shows a service distance that can occur in the normal CP of about 4.7 us in the LTE OFDMA scheme for the relay apparatus 100 according to the present invention having the equipment delay of about 3 us and the relay apparatus 100 according to the present invention of about 0.5 us. .

When the RF repeater 100 and 200 having the equipment delays of about 0.5 us and 3 us are installed at 2 us from the base station, the RF repeater 100 having the equipment delay of 0.5 us is approximately 4.65 us due to the Normal CP of about 4.7 us = 1.4Km). However, the RF repeater 200 having the equipment delay of 3us is able to service only about 1.7us (service distance = 0.5km) due to the normal CP of about 4.7us.

Therefore, it can be seen that the service distance is extended by the RF repeater 100 of the present invention having a very small delay compared to the conventional RF repeater 200 due to the Normal CP of about 4.7 us in the LTE OFDMA scheme.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

100: Relay device
111: Donor antenna
112: Service antenna
121, 122: Duplex
130: Downstream signal amplification unit
131: Frequency down converter of the downstream signal amplifying unit
131e: IF filter of the downstream signal amplifying part
133: Frequency up converter of the downstream signal amplifying part
150: Upstream signal amplifying unit
151: Frequency down converter of the upstream signal amplifying unit
151e: IF filter of the upstream signal amplifying unit
153: Frequency up-converter of up-signal amplifier

Claims (8)

A relay apparatus for amplifying a superheterodyne system, comprising:
A frequency down converter for converting the received high frequency band OFDMA RF signal into an intermediate frequency band OFDMA IF signal;
An IF filter that performs filtering to obtain a desired intermediate frequency band signal in the converted intermediate frequency band OFDMA IF signal; And
And a frequency up-converter for converting an intermediate frequency band signal output from the IF filter into an OFDMA RF signal of a high frequency band,
The frequency down converter converts the OFDMA RF signal of the high frequency band into an OFDMA IF signal of an intermediate frequency band of 1 GHz or more in frequency so as to extend the service distance within a normal CP (Cyclic Prefix) of the OFDMA system, The IF filter is a filter having a delay of 1 usec or less and is formed of at least one of a cavity filter, a DR-Cavity filter, a DR (Dielectric Resonator) filter, and a FBAR (Film Bulk Acoustic Resonator) To the mobile communication system. delete The method according to claim 1,
Wherein the frequency down converter, the IF filter, and the frequency up converter are installed on a forward signal path. The method according to claim 1,
Wherein the frequency down converter, the IF filter, and the frequency up converter are installed on a reverse signal path. A relaying method for amplification in a superheterodyne manner,
(a) converting an OFDMA RF signal of a received high frequency band into an OFDMA IF signal of an intermediate frequency band;
(b) performing filtering to obtain a desired intermediate frequency band signal in the converted intermediate frequency band OFDMA IF signal; And
(c) converting the filtered intermediate frequency band signal into an OFDMA RF signal of a high frequency band and outputting the converted signal,
The step (a) converts the OFDMA RF signal of the high frequency band into an OFDMA IF signal of an intermediate frequency band of 1 GHz or more in frequency so as to extend the service distance in a normal CP (Cyclic Prefix) of the OFDMA system ,
In the step (b), filtering is performed using an IF filter having a delay of 1 microseconds or less, and a filter such as a Cavity filter, a DR-Cavity filter, a DR (Dielectric Resonator) filter, Acoustic Resonator) filter is used as the IF filter. delete 6. The method of claim 5,
Wherein said step (a), said step (b), and said step (c) are performed on a forward signal path. 6. The method of claim 5,
Wherein said step (a), said step (b), and said step (c) are performed on a reverse signal path.

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