KR102594478B1 - Apparatus for System Signal Delay Improving of RF Repeater - Google Patents

Abstract

The present invention relates to a device for improving the system signal delay of an RF repeater. By processing the original signal as is without an intermediate frequency conversion process, it not only reduces the duplexer filter size, but also reduces the signal delay of the repeater system, eliminating the problem of interference in wireless cell overlap areas. The purpose is to solve the problem and increase wireless data traffic capacity accordingly.

Description

Apparatus for System Signal Delay Improving of RF Repeater}

The present invention reduces the system delay of the repeater and increases data traffic by processing the raw signal only through filtering, gain adjustment, and attenuation without the intermediate frequency (IF: Immediate Frequency) signal processing of the RF repeater (Radio Frequency Repeater) and up/down converter. This relates to a system signal delay improvement device for RF repeaters that improves wireless environmental performance.

As mobile communication technology evolves, 5G (The Fifth Generation) is commercialized and is gaining momentum in the market. Many countries, operators, and companies are making efforts to improve 5G performance, and are accelerating the development of 5G mobile communication equipment, so technological development continues to evolve in accordance with standardization. Following LTE (4G) technology, 5G technology development is divided into Sub-6GHz (f<6GHz) and mmWAVE (f>6GHz). Technical elements such as frequency, bandwidth, subcarrier frequency, and physical layer modem in the 5G Standard can be customized and applied in the field.

As communication systems evolve, latency in the system is becoming an important factor. Modulation/demodulation technology is developing with the evolution of OFDM technology in communication technology, and accordingly, the latency of radio waves when transmitting and receiving wireless signals in communication is shortening. With these technological developments, the signal delay of all repeater systems should also be shortened.

In addition, as communication technology progresses to 4G and 5G, modulation in OFDM (Orthogonal Frequency Division Multiplexing) is designed to transmit and receive data in symbol units. Accordingly, a disadvantage of OFDM technology is that inter-symbol interfaces (radio interference, crosstalk) occur. To compensate for this (remove interference between symbols), a cyclic prefix (CP) is added between symbols to reduce interference between symbols. CP is also related to communication network coverage. Communication network coverage and system delay are limited depending on the time interval of the CP. Accordingly, there is a demand for technology that can use coverage or system delay according to the CP time interval without restrictions.

Referring to Table 1 below, in 4th generation mobile communication (4G), CP (4.69us), and in 5th generation mobile communication (5G), it varies depending on SCS (Subcarrier Spacing frequency): SCS30KHz (CP 2.34us), SCS60KHz (CP 1.17us) ), SCS120KHz (CP 0.57us), and SCS240KHz (CP 0.29us) are determined.

Due to this CP, wireless transmission and reception can be performed without problems in a wireless communication environment only if the system delay is within CP. Typically, repeater equipment consists of a variety of equipment with a system delay of about 1.5us to 4.5us, and requires low system delay equipment of 300ns or less.

Figure 1 is a configuration diagram of a repeater system according to the prior art, in which an RF signal transmitted from a base station is received through the donor antenna 101, and the received RF signal is transmitted as a downward signal (DL: Down) through the first duplexer 102. Link) is separated, amplified through a low noise amplifier (LNA), and then converted to an intermediate frequency band (IF) signal through the downconverter (110).

The IF signal of the down converter 110 is filtered using an IF filter to obtain a signal in the desired intermediate frequency band in the IF signal processing unit 120.

The signal in the intermediate frequency band filtered by the IF signal processing unit 120 is converted into a high frequency band RF signal through the upconverter 130, and then converted to a second duplexer through processes such as amplification, RF filtering, attenuation, and power amplification. It is input as (103), and is transmitted to the user terminal through the service antenna (104).

The uplink signal (UL: Up Link) received through the service antenna 103 is separated from the uplink signal (UL) through the second duplexer 103, amplified through a low noise amplifier (LNA), and then converted to a downconverter ( 140) to convert it into an intermediate frequency signal (IF).

The IF signal of the down converter 140 is filtered using an IF filter to obtain a signal in the desired intermediate frequency band in the IF signal processing unit 150.

The intermediate frequency band signal filtered in the IF signal processing unit 150 is converted into a high frequency band RF signal through the upconverter 160, and then through a process of amplification, RF filtering, attenuation, and power amplification, the first duplexer It is input as (102), and is transmitted to the base station through the donor antenna (101).

Here, most of the system delay is taken up by the IF filter of the IF signal processing unit 120. Even in analog and digital signal processing, system delay dominates most of the IF signal processing units 120 and 150.

Additionally, referring to FIG. 2, a conventional relay system must maintain its own signal band (In-Band) and remove other signal bands (Out-Band). Accordingly, analog SAW (Surface Acoustic Wave) filters 121 and 151 are used to remove other band signals.

The SAW filters 121 and 151 have a rejection characteristic of more than 40 to 50 dB of other signal bands. Due to these filter characteristics, it is used to operate without problems in the relay system. As it has good characteristics, there is a filter delay. Mainly, the SAW filter delay is 1.0 ~ 2.0us, digital IF signal processing includes IF SAW filters (121) (151), and the signal processing delay speed including ADC/DAC processing delay, DSP processing delay, etc. is up to 4.0 ~ 5.0us. Occurs.

The system delay of a typical RF repeater has a delay speed of about 1.5 to 5.0us. This is possible without problem in a wireless environment with SCS15KHz @ CP 4.67us. However, in 5G, it varies depending on the Subcarrier Spacing frequency (SCS). In SCS30KHz (CP 2.34us), SCS60KHz (CP 1.17us), SCS120KHz (CP 0.57us), and SCS240KHz (CP 0.29us), system interconnection may or may not be possible without problems. There are many cases. If the system delay is large, it is difficult to apply it to the 5G system.

Additionally, the first and second duplexers 102 and 103 have different filter characteristics and sizes depending on frequency characteristics. At low frequencies, in order to improve the filter characteristics, the size and weight are large and heavy, which makes it unsuitable for use in actual relay system equipment. The duplexer filter is large in size and heavy, so when mounted in a repeater system, assembly is not good due to the size. There are limited space usage constraints in equipment design. Due to its large size and heavy weight, the duplexer filter characteristics were moderated in the repeater system design, and the intermediate signal processing unit performed intermediate signal processing to satisfy performance to design and develop the system. In order to satisfy performance in this intermediate signal processing unit, there was a problem in that the circuit became more complex and the number of parts increased, resulting in an increase in size and weight.

Domestic Patent Registration No. 10-1415753 (announcement date 2014.07.08.)

Therefore, in order to improve the problems of the prior art, the present invention not only reduces the duplexer filter size by processing the original signal without an intermediate frequency conversion process, but also solves the problem of interference in wireless cell overlap areas by reducing the repeater system signal delay. The purpose is to provide a system signal delay improvement device for RF repeaters that increases wireless data traffic capacity accordingly.

The system signal delay improvement device of the RF repeater to achieve the purpose of the present invention separates the RF signals transmitted and received between the donor antenna and the service antenna on the base station and the user terminal into upward or downward, and processes the RF raw signal to determine the specific signal. A system delay improvement device for an RF repeater that extracts only a signal band, comprising: a first duplexer that extracts only a downstream signal and a specific band signal from an RF signal received through the donor antenna; a first RF signal processing unit that removes noise and adjusts the gain of a downstream signal in a specific band output from the first duplexer; a second duplexer that transmits the downstream signal output through the first RF signal processing unit to a service antenna and extracts only a specific band signal from the upstream signal received through the service antenna; And a second RF signal processing unit that removes noise and adjusts the gain of the upstream signal of a specific band output from the second duplexer and transmits it to the first duplexer.

The first RF signal processing unit includes an 11th band filter for increasing frequency selectivity and removing noise signals from the signal input through the first duplexer; an 11th amplifier that amplifies the signal level passing through the 11th band filter; an 11th attenuator to prevent overflow of the signal amplified through the 11th amplifier; a twelfth amplifier that amplifies the signal attenuated through the eleventh attenuator; a 12th band filter that removes noise from the signal amplified through the 12th amplifier; and a 13th amplifier for amplifying the signal that has passed through the 12th band filter.

The second RF signal processing unit includes a 21st band filter for removing noise of the upward signal passing through the second duplexer; a 21st amplifier that amplifies the signal level passing through the 21st band filter; a 21st attenuator to prevent overflow of the signal amplified through the 21st amplifier; a 22nd amplifier that amplifies the signal attenuated through the 21st attenuator; a 22nd band filter that removes noise from the signal amplified through the 22nd amplifier; and a 23rd amplifier for amplifying the signal that has passed through the 22nd band filter.

The system signal delay improvement device of the RF repeater according to the present invention not only separates the upstream and downstream signals at the duplexer, but also occupies the high frequency band in 5G due to the band removal characteristic of removing signals in other companies' bands other than a specific band. This has the effect of enabling miniaturization and weight reduction of the duplexer filter.

In addition, since the signal band of other companies has been removed from the duplexer, not only is there no need for a SAW filter, but also frequency downconversion, IF filter, and frequency upconversion due to intermediate frequency conversion, PLL for SAW filter signal processing, and synthesizer (Mixer) are used. ), the hardware system configuration is simple as the original RF signal that has passed through the duplexer is processed as is without the need for configuration, and the system signal delay can be improved, thereby solving the problem of interference in wireless cell overlap areas and resulting wireless It has the effect of increasing data traffic capacity.

1 is a configuration diagram of a repeater system according to the prior art,
Figure 2 is a waveform diagram for explaining the removal of other bands in the SAW filter in Figure 1;
Figure 3 is a configuration diagram of a system signal delay improvement device for an RF repeater according to an embodiment of the present invention;
Figure 4 is a waveform diagram for explaining the removal of other bands in the duplexer of Figure 2;
Figure 5 is a flowchart of the operation process of Figure 2.

The features and effects of the present invention described above will become more apparent through the following detailed description in conjunction with the accompanying drawings, and accordingly, those skilled in the art will be able to easily implement the technical idea of the present invention. You will be able to.

Since the present invention can be subject to various changes and can have various forms, specific embodiments will be illustrated and described in detail in the text.

However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention.

The apparatus and method for improving system signal delay of an RF repeater according to a preferred embodiment of the present invention will be described in detail with reference to the attached drawings as follows.

Referring to FIG. 2, the RF downlink signal and the RF upstream signal are separated from the RF signal transmitted and received from the donor antenna 101 on the base station side, and the RF downlink signal extracts only a specific band signal and removes the remaining band signals. 1 duplexer 210, a low noise amplifier (LNA-1) that amplifies the signal component of the RF downlink signal of a specific band output from the first duplexer 210 and reduces the noise signal, and the low noise amplifier (LNA-1) A first RF signal processing unit 220 that removes noise and adjusts the gain of the RF downstream signal output through -1), and a downstream signal power amplifier that amplifies the RF downstream signal of the first RF signal processing unit 220 to enable wireless output. (PA-1) and the RF downstream signal amplified from the downstream signal power amplifier (PA-1) is transmitted to the service antenna 104, and only a specific band signal is transmitted from the RF upstream signal input to the service antenna 102. A second duplexer 230 that extracts, and a second RF signal processor 240 that removes noise and performs gain adjustment of the RF upstream signal of a specific band output from the second duplexer 230, and the second RF signal processor It consists of an upstream signal power amplifier (PA-1) that amplifies the RF upstream signal from 240 to enable wireless output and inputs it to the first duplexer 210.

The first RF signal processing unit 220 includes an 11th band filter 221 for increasing frequency selectivity and removing noise signals from the RF downlink signal input through the low noise amplifier (LNA-1), and the 11th band filter 221. An 11th amplifier 222 that amplifies the signal level passing through the band filter 221, and an attenuator to prevent overflow of the RF downlink signal amplified through the 11th amplifier 222. An 11th attenuator 223, a 12th amplifier 224 that amplifies the RF downlink signal attenuated through the 11th attenuator 223, and removes noise from the RF downlink signal amplified through the 12th amplifier 224. It consists of a 12th band filter 225 that amplifies the RF downlink signal passing through the 12th band filter 225 and a 13th amplifier 226.

The second RF signal processing unit 240 includes a 21st band filter 241 for removing noise of the RF upstream signal passing through the second duplexer 230, and a signal level passing through the 21st band filter 241. A 21st amplifier 242 that amplifies, a 21st attenuator 243 to prevent overflow of the RF upstream signal amplified through the 21st amplifier 242, and a 21st attenuator 243 that is attenuated through the 21st attenuator 243. A 22nd amplifier 244 that amplifies the RF upstream signal, a 22nd band filter 245 that removes noise from the RF upstream signal amplified through the 22nd amplifier 244, and the 22nd band filter 245 It consists of a 23rd amplifier (246) that amplifies the RF upstream signal that has passed through.

The specific operation of the present invention configured as described above will be described in detail with reference to FIGS. 2 to 5 as follows.

First, the present invention not only separates the RF downstream signal and RF upstream signal of the donor antenna and service antenna of the RF repeater from the duplexer, but also removes the signal band of other companies, so that the intermediate frequency (IF) System gain control is performed on the RF upstream signal and RF downstream signal without intermediate frequency signal processing such as conversion, IF filter, SAW filter, and PLL gain control.

Referring to Figures 3 and 5, after the RF signal from the base station is received through the donor antenna 101, the first duplexer 210 separates and extracts the RF downlink signal, and extracts the RF downlink signal as a signal in a specific band. do.

Referring to FIG. 4, the first and second duplexers 210 are not only capable of separating RF downstream signals and RF upstream signals, but also can output third-party band signals (Out-Band) excluding the company's preset specific band (In-Band) signals. -Band) is removed (40 to 50 dB), which shows the same performance compared to the SAW filters 121 and 151 in Figures 1 and 2 of the prior art, and the first and second duplexers (210) (230) Because the 5G system is occupied by a high frequency band, it is possible to design a relay system with good performance even if the duplexer filter is miniaturized and lightweight.

The RF downlink signal of the company's specific band that has passed through the first duplexer 210 amplifies the signal component and reduces the noise signal through a low noise amplifier (LNA-1), and then reduces the noise signal through the first RF signal processor 220. Perform rejection and gain adjustment.

In more detail, the first RF signal processing unit 220 increases the frequency selectivity of the RF downlink signal that has passed through the low noise amplifier (LNA-1) through the 11th band filter 221 and removes the noise signal. The RF downlink signal that has passed through the 11th band filter 221 is amplified to a certain signal level through the 11th amplifier 222, and then the 11th attenuator ( 223), the attenuated RF downward signal is amplified in the 12th amplifier 224, noise is removed from the amplified RF downward signal in the 12th band filter 225, and the It is amplified through the 13th amplifier 226 and output to the second duplexer 230 through the power amplifier (PA-1).

In this way, the first RF signal processing unit 220 controls the gain of the RF downlink signal, which is an RF original signal, so a relay system can be configured without intermediate frequency (IF) signal processing and frequency up/down converters as in the prior art. Since it exists within the CP time (Cyclic Prefix Time) according to the 4G and 5G SCS (Subcarrier Spacing frequency), it also solves the problem of Inter Symbol Interference (ISI) in the wireless environment due to signal delay in the repeater system. do.

In other words, the present invention does not require a mixer or PLL unit of the prior art down converter, so there is no signal attenuation due to filtering, a separate gain amplifier is not needed, and the system gain is adjusted using an attenuation and gain amplifier without an intermediate frequency signal processor. . This simplifies the circuit, reduces system signal delay, and increases wireless data traffic capacity.

The RF downstream signal whose system gain has been adjusted through the first RF signal processing unit 220 is input to the second duplexer 103 after noise removal and gain adjustment of the RF downstream signal through the power amplifier (P.A-1) to RF A downward signal is transmitted to the terminal through the service antenna 104.

The RF upstream signal received through the service antenna 104 is extracted separately from the RF downlink signal in the second duplexer 103, and then, like the first duplexer 210, the signal band of another company is removed and the RF upstream signal is extracted from the RF downlink signal in the second duplexer 103. After only the signal band is passed, the signal component is amplified and the noise signal is reduced through the low noise amplification unit (LNA-2), and then noise removal and gain adjustment are performed through the second RF signal processing unit 240.

That is, the second RF signal processing unit 240 performs signal processing in the reverse direction of the first RF signal processing unit 220, and more specifically, the RF upstream signal input from the low noise amplifier (LNA-2) is transmitted to the first RF signal processing unit 220. Frequency selectivity is increased and noise signals are removed through the 21-band filter 241.

The RF upstream signal that has passed through the 21st band filter 241 is amplified to a certain signal level through the 21st amplifier 242, and then the 21st attenuator ( 243), the attenuated RF upstream signal is amplified in the 22nd amplifier 244, noise is removed from the amplified RF upstream signal in the 22nd band filter 245, and the It is amplified through the 23rd amplifier 246 and output to the first duplexer 210 through the power amplifier (PA-2).

The first duplexer 210 separates the RF upstream signal input through the power amplifier (PA-2) and transmits it to the base station through the donor antenna 101.

As described above, although the system signal delay improvement device of the RF repeater according to the embodiment of the present invention has been described by means of limited embodiments and drawings, it is not limited by these embodiments and is based on common knowledge in the technical field to which the present invention pertains. Of course, various modifications and variations can be made by those having the same within the technical spirit of the present invention and the equivalent scope of the claims described below.

101: donor antenna 104: service antenna
210, 230: 1st, 2nd duplexer 220,240: 1st, 2nd RF signal processing unit
221: 11th band filter 222: 11th amplifier
223: 11th attenuator 224: 12th amplifier
225: 12th band filter 226: 13th amplifier
241: 21st band filter 242: 21st amplifier
243: 21st attenuator 244: 22nd amplifier
245: 22nd band filter 246: 23rd amplifier

Claims (6)

In the system signal delay improvement device of the RF repeater, which separates the RF signals transmitted and received between the base station and the user terminal through a donor antenna or service antenna into upward or downward, and processes the RF raw signal to extract only a specific signal band,
a first duplexer that extracts only an RF downlink signal and a specific band signal from the RF signal received through the donor antenna;
a first RF signal processing unit that removes noise and adjusts the gain of the RF downlink signal of a specific band output from the first duplexer;
a second duplexer that transmits the RF downlink signal output through the first RF signal processing unit to a service antenna and extracts only a specific band signal from the RF upstream signal transmitted from the service antenna; and
A second RF signal processing unit that removes noise and adjusts the gain of the RF upstream signal of a specific band output from the second duplexer and transmits it to the first duplexer,
The first RF signal processing unit includes an 11th band filter for increasing frequency selectivity and removing noise signals from the RF downlink signal input through the first duplexer;
an 11th amplifier that amplifies the signal level passing through the 11th band filter;
an 11th attenuator for preventing overflow of the RF downlink signal amplified through the 11th amplifier;
a twelfth amplifier that amplifies the RF downward signal attenuated through the eleventh attenuator;
a 12th band filter that removes noise from the RF downlink signal amplified through the 12th amplifier; and
A 13th amplifier that amplifies the RF downlink signal that has passed through the 12th band filter. A system signal delay improvement device for an RF repeater, comprising: According to paragraph 1,
The first duplexer separates the RF downlink signal and the RF upstream signal from the received RF signal, removes RF signals other than those in a specific band set from the separated RF downlink signal, and filters only the RF downlink signal in its own band. A system signal delay improvement device for RF repeaters that has the following characteristics. According to paragraph 1,
The second duplexer separates the RF upstream signal and the RF downstream signal from the received RF signal, removes RF signals other than those in a specific band set from the separated RF upstream signal, and filters only the RF upstream signal in its own band. A system signal delay improvement device for RF repeaters that has the following characteristics. delete In the system signal delay improvement device of the RF repeater, which separates the RF signals transmitted and received between the base station and the user terminal through a donor antenna or service antenna into upward or downward, and processes the RF raw signal to extract only a specific signal band,
a first duplexer that extracts only an RF downlink signal and a specific band signal from the RF signal received through the donor antenna;
a first RF signal processing unit that removes noise and adjusts the gain of the RF downlink signal of a specific band output from the first duplexer;
a second duplexer that transmits the RF downlink signal output through the first RF signal processing unit to a service antenna and extracts only a specific band signal from the RF upstream signal transmitted from the service antenna; and
A second RF signal processing unit that removes noise and adjusts the gain of the RF upstream signal of a specific band output from the second duplexer and transmits it to the first duplexer,
The second RF signal processing unit includes a 21st band filter for removing noise of the RF upstream signal passing through the second duplexer;
a 21st amplifier that amplifies the signal level passing through the 21st band filter;
a 21st attenuator for preventing overflow of the RF upstream signal amplified through the 21st amplifier;
A 22nd amplifier that amplifies the RF upstream signal attenuated through the 21st attenuator;
a 22nd band filter that removes noise from the RF upstream signal amplified through the 22nd amplifier; and
A system signal delay improvement device for an RF repeater, comprising: a 23rd amplifier for amplifying the RF upstream signal that has passed through the 22nd band filter. According to claim 1 or 5,
A system signal delay improvement device for an RF repeater, characterized in that the first and second RF signal processing units control the gain of the original RF signal without intermediate frequency (IF) conversion and signal processing.