KR20140081501A - System and method for synchronization of relay node - Google Patents

System and method for synchronization of relay node Download PDF

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Publication number
KR20140081501A
KR20140081501A KR1020120151328A KR20120151328A KR20140081501A KR 20140081501 A KR20140081501 A KR 20140081501A KR 1020120151328 A KR1020120151328 A KR 1020120151328A KR 20120151328 A KR20120151328 A KR 20120151328A KR 20140081501 A KR20140081501 A KR 20140081501A
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South Korea
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signal
synchronization
voltage
oscillation
radio
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KR1020120151328A
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Korean (ko)
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유기한
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주식회사 케이티
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Publication of KR20140081501A publication Critical patent/KR20140081501A/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/155—Ground-based stations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/001—Synchronization between nodes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/0055—Synchronisation arrangements determining timing error of reception due to propagation delay
    • H04W56/0095—Synchronisation arrangements determining timing error of reception due to propagation delay estimated based on signal strength

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Radio Relay Systems (AREA)

Abstract

In an environment where a base station is separated into a digital signal processing unit and a radio signal processing unit, a synchronization acquisition system in conjunction with the radio signal processing unit receives a radio signal from the radio signal processing unit and extracts a PSS and an SSS as a reference signal for acquiring the synchronization of a relay. The system compares phases of a synchronization signal and an oscillation signal and corrects the oscillation signal by a phase difference after generating the synchronization signal based on the reference signal and generating the oscillation signal of the relay. And the system outputs the radio signal in accordance with the oscillation signal which has been corrected.

Description

[0001] The present invention relates to a synchronous acquisition system and method for a repeater,

The present invention relates to a synchronization acquisition system and method of a repeater.

In order to expand coverage in mobile communication systems, coverage is being expanded using repeaters as well as base stations. At this time, various types of repeaters are used such as optical repeaters, RF (Radio Frequency) repeaters, and M / W (Micro Wave) repeaters. One of the biggest problems of these repeaters is synchronizing.

The GPS (Global Positioning System) module is most commonly used to synchronize. Since it receives the GPS signal used in the satellite and provides the synchronization of the repeater, the most stable signal can be obtained.

However, when the GPS module is used, since it can receive a weak GPS signal indoors, there is a restriction in use. And because it can be affected by the weather or the surrounding environment, it is inevitable to use a separate antenna without using the GPS module. However, if a separate antenna is used, many problems such as damage to the beauty of the building and complaints are caused.

Therefore, it is proposed to use OCXO (Oven Controlled Crystal Oscillator) to solve this problem. This method is advantageous in that it does not need to install an antenna since it operates on OCXO without any additional synchronization. However, since the OCXO is expensive, it causes economical problems, and there is a problem that it must be periodically corrected since the phase and frequency change with time.

Accordingly, the present invention provides a synchronization acquisition system and method of a repeater that extracts a synchronization signal from an LTE (Long Term Evolution) signal itself and maintains synchronization of the repeater.

According to another aspect of the present invention, there is provided a system for acquiring synchronization of a repeater interworking with a radio signal unit in an environment in which a base station is divided into a digital signal processor and a radio signal processor,

A signal receiver for receiving a radio signal transmitted from the radio signal processor; A signal extracting unit for extracting a reference signal to be used for synchronization acquisition from the radio signal; A synchronization signal generator for generating a synchronization signal using the reference signal; A voltage controlled oscillator that generates an oscillation signal and corrects a phase of the generated oscillation signal by a frequency corresponding to an input reference signal or a voltage signal; And a control unit for receiving the oscillation signal generated by the voltage control oscillator and the synchronization signal generated by the synchronization signal generation unit to compare phases of the oscillation signal and the synchronization signal and generating a voltage signal corresponding to a phase difference between the oscillation signal and the synchronization signal A phase detector for detecting the phase difference; And a main hub unit for receiving the phase-corrected oscillation signal from the voltage-controlled oscillator and the radio signal received by the signal receiver, and outputting the radio signal according to the corrected oscillation signal.

Wherein the synchronization acquisition system divides an oscillation signal according to a voltage level of an oscillation signal output from the voltage control oscillator or a voltage signal generated by the phase detection unit by a predetermined division ratio to reduce the frequency and output the oscillation signal to the phase detection unit .

The synchronization acquisition system includes an analog / digital converter for converting an analog radio signal received by the signal receiver into a digital signal; A serial-to-parallel converter for converting the digital signal converted by the analog-to-digital converter into a parallel signal; And a fast Fourier transformer for fast Fourier-transforming the digital signal converted into the parallel signal by the serial-to-parallel converter.

The phase detector may generate a phase difference between the oscillation signal generated by the voltage-controlled oscillator and the reference signal extracted by the signal extractor as the reference signal.

The reference signal may use a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) as a reference signal.

According to another aspect of the present invention, there is provided a method for acquiring a synchronization of a repeater, the method including acquiring synchronization of a repeater in an environment in which a base station is separated into a digital signal processor and a radio signal processor, silver,

Receiving a radio signal from the radio signal processor and extracting PSS and SSS as a reference signal from the radio signal; Generating a synchronization signal based on the reference signal; Generating an oscillation signal of the repeater itself; Comparing the phase of the synchronization signal and the oscillation signal to correct the oscillation signal by a phase difference; And outputting the radio signal in accordance with the corrected oscillation signal.

The step of correcting the oscillation signal may include: generating a voltage corresponding to a phase difference by comparing phases of the synchronization signal and the oscillation signal; Generating the generated voltage as a voltage signal; And correcting the oscillation signal by a frequency corresponding to a voltage level of the voltage signal based on the generated voltage signal.

Comparing the phase of the extracted reference signal with the phase of the oscillation signal to generate a reference signal if the synchronizing signal is not input before the step of generating the voltage; And correcting the oscillation signal by a frequency corresponding to a voltage level of the voltage signal based on the reference signal.

According to the present invention, it is possible to prevent the phase and frequency from being shifted when the repeater is used for a long period of time.

Also, the synchronization of the repeater can be obtained without installing a separate antenna.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exemplary view illustrating a repeater connection of a general integrated type base station.
2 is an exemplary view illustrating a repeater connection in a conventional base station detachable structure.
3 is a structural diagram of a synchronization acquisition system according to an embodiment of the present invention.
4 is a flowchart illustrating a method of acquiring a synchronization according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

In this specification, a terminal includes a mobile station (MS), a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS) An access terminal (AT), and the like, and may include all or some of functions of a mobile terminal, a subscriber station, a mobile subscriber station, a user equipment, and the like.

In this specification, a base station (BS) is an access point (AP), a radio access station (RAS), a node B, a base transceiver station (BTS) Mobile Multihop Relay) -BS, and may include all or some of the functions of an access point, a radio access station, a Node B, a base transceiver station, and an MMR-BS.

Hereinafter, a synchronous acquisition system and method of a repeater according to an embodiment of the present invention will be described with reference to the drawings. Before describing an embodiment of the present invention, a general system environment will be described first.

FIG. 1 is an exemplary view illustrating a repeater connection of a general integrated type base station, and FIG. 2 is an exemplary view illustrating a repeater connection in a conventional base station detachable structure.

FIG. 1 generally shows a case where a base station is an integrated type in which a base station is not separated, and a repeater is connected to extend coverage. The base station 10 includes a digital signal processing unit for processing a digital signal and a radio signal processing unit for processing a radio signal, and most of them provide a reference signal. The repeater 20 connected to the base station 10 receives the synchronization signal from the base station 10 and acquires synchronization to acquire synchronization.

2, the digital signal processing unit 30 and the wireless signal processing unit 40 are separated from each other, and the digital signal processing unit 30 and the wireless signal processing unit 40 are connected to each other using light. Is being designed. At this time, the repeater 20 is connected to the radio signal processing unit 40, and the structure of the radio signal processing unit 40 is designed to be minimal.

 Therefore, the wireless signal processing unit 40 does not provide a synchronization signal or a synchronization module to the repeater 20 connected thereto, and accordingly, the repeater 20 does not receive a separate synchronization signal or a synchronization module from the wireless signal processing unit 40 The GPS module or the OCXO is used to acquire the synchronization, which causes conventional problems.

Therefore, in the embodiment of the present invention, the synchronization signal is extracted from the LTE signal itself to maintain the synchronization of the repeater, and the structure of the synchronization acquisition system 100 will be described with reference to FIG. At this time, synchronization is maintained in the repeater by using a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS), which are used when the mobile station receives initial synchronization, among the signals transmitted from the base station.

3 is a structural diagram of a synchronization acquisition system according to an embodiment of the present invention.

3, the synchronization acquisition system 100 includes a signal receiving unit 101, an analog / digital conversion unit 102, a serial-parallel conversion unit 103, a fast Fourier transform unit 104, a signal extraction unit 105, a synchronization signal generator 106, a phase detector 107, a frequency divider 108, a voltage controlled oscillator 109, and a main hub unit 110.

The signal receiving unit 101 receives a signal transmitted from the radio signal processing unit of the base station. In this case, the signal is analog type and the signal includes PSS, SSS, Physical Downlink Shared Channel (PDSCH), Physical Broadcast Channel (PBCH), and reference signal. Here, the PSS and the SSS are signals used by the UE to obtain the initial synchronization, and in the embodiment of the present invention, the repeater will use both the PSS and the SSS signals when acquiring synchronization.

The analog-to-digital converter 102 converts the analog signal received by the signal receiver 101 into a digital signal, and the serial-to-parallel converter 103 converts the serial digital signal into a parallel digital signal. The fast Fourier transformer 104 performs Fast Fourier Transform (FFT) on the parallel digital signals output from the serial-to-parallel converter 103. [ A method of converting an analog signal into a digital signal in the analog / digital conversion unit 102, a method of converting a serial signal into a parallel signal in the serial-parallel conversion unit 103, a method of performing a fast Fourier transform in the fast Fourier transform unit 104 And detailed description thereof will be omitted in the embodiment of the present invention.

The signal extracting unit 105 extracts PSS and SSS from the fast Fourier transformed signals at the fast Fourier transform unit 104. [ In the embodiment of the present invention, these signals are referred to as a "reference signal". Since the positions of the PSS and the SSS are located in a known region of the LTE signal structure, a detailed description of a method of extracting the PSS and the SSS from the signal extracted by the signal extracting unit 105 is omitted.

In the embodiment of the present invention, a DSP (Digital Signal Processor) is used as the signal extracting unit 105, but the present invention is not limited thereto. Also, the signal extracting unit 105 can extract the reference signal from among the plurality of signals by using various methods. Therefore, the method is not limited to any one method.

The synchronization signal generation unit 106 generates a synchronization signal using the reference signal extracted by the signal extraction unit 105. The method of generating the synchronization signal using the reference signal can be implemented by various methods and is not limited to any one method.

If the synchronization signal generated by the synchronization signal generation unit 106 has not yet been input, the phase detection unit 107 can not compare how much phase difference is generated between the synchronization signal and the oscillation signal. Therefore, the voltage-controlled oscillator 109 generates a reference signal from the phase difference between the oscillation signal of the high frequency generated for oscillation of the repeater itself and the reference signal extracted by the signal extraction unit 105. The frequency of the generated reference signal is lowered through the frequency divider 108 and then used to compare the phase difference with the input synchronizing signal.

If the synchronization signal has already been input, the phase detector 107 compares the phase difference between the synchronization signal and the oscillation signal output from the frequency divider 108. And generates and outputs a voltage signal representing the degree of phase difference as a voltage.

The frequency divider 108 divides the oscillation signal of the high frequency generated by the voltage-controlled oscillator 109 by the frequency division ratio N, which is a predetermined ratio, and outputs the frequency by lowering the frequency of the oscillation signal. In the embodiment of the present invention, it is assumed that the voltage controlled oscillator 109 generates an oscillation signal of 10 MHz. In the frequency divider 108, an oscillation signal of 10 MHz is generated as an oscillation signal of several tens of KHz and is input to the phase detector 107 . The frequency divider 108 also divides the output signal of the frequency according to the voltage level of the voltage signal by the frequency division ratio N to lower the frequency and outputs the frequency to the phase detector 107.

A voltage controlled oscillator (VCO) 109 generates an oscillation signal of a high frequency by a predetermined method and transmits it to the frequency divider 108. When receiving the reference signal or the voltage signal from the phase detector 107, the voltage-controlled oscillator 109 corrects the phase of the generated oscillation signal by a frequency corresponding to the voltage level of the reference signal or the voltage level of the voltage signal, And transmits the generated oscillation signal to the main hub unit 110. Since various methods can be used for correcting the oscillation signal, the embodiment of the present invention is not limited to any one example.

The main hub unit 110 receives the phase-corrected oscillation signal from the voltage-controlled oscillator 109 and the radio signal received by the signal receiver 101, and converts the radio signal into an optical signal. The converted optical signal is output in accordance with the phase-corrected oscillation signal to provide services to users.

A method of acquiring the synchronization of the repeater using the above-described synchronization acquisition system 100 will be described with reference to FIG.

4 is a flowchart illustrating a method of acquiring a synchronization according to an embodiment of the present invention.

4, when the signal receiving unit 101 of the synchronization acquisition system 100 included in the repeater receives the radio signal transmitted from the radio signal unit (S100), the signal extracting unit 105 extracts the radio signal from the radio signal The reference signal is extracted (S110). The reference signal extracted in step S110 extracts SSS and PSS among a plurality of signals included in the radio signal as reference signals. Procedures for converting an analog signal into a digital signal, a procedure for converting a serial signal into a parallel signal, and a procedure for performing a fast Fourier transform are already known between steps S100 and S110, and a detailed description thereof will be omitted in the embodiment of the present invention.

When the signal extraction unit 105 extracts the reference signal, the synchronization signal generation unit 106 generates a synchronization signal using the reference signal (S120). Since a method of generating a synchronization signal using a reference signal can be used in various methods, the present invention is not limited to any one method.

The voltage-controlled oscillator 109 generates a reference signal according to a predetermined method and transmits it to the frequency divider 108 (S130). The phase detector 107 compares the phase of the synchronizing signal generated by the synchronizing signal generator 106 with the phase of the reference signal or oscillation signal received through the frequency divider 108. The phase detector 107 generates a voltage according to the phase difference to generate a voltage signal, and transmits the generated voltage signal to the voltage controlled oscillator 109 (S140).

At this time, if the synchronizing signal is not inputted from the synchronizing signal generating unit 106, a voltage corresponding to the phase difference between the reference signal extracted by the signal extracting unit 105 and the oscillation signal generated by the voltage controlled oscillator 109 is generated, And transmits it to the voltage-controlled oscillator 109. Upon receiving the voltage signal or the reference signal from the phase detector 107, the voltage-controlled oscillator 109 corrects the phase of the oscillation signal generated in step S130 by a frequency corresponding to the voltage level of the voltage signal. Then, the phase-corrected oscillation signal is transmitted to the main hub unit 110 (S150).

The main hub unit 110 outputs the radio signal received in step S100 in accordance with the phase-corrected oscillation signal in step S150, and provides a service to the users in step S160. When the synchronization of the repeater is acquired in accordance with the wireless signal unit in this manner, it is possible to prevent the phase or frequency from being shifted when the repeater is used for a long period of time, thereby providing a stable service.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (9)

A system for acquiring synchronization of a repeater interworking with a radio signal unit in an environment in which a base station is separated into a digital signal processing unit and a radio signal processing unit,
A signal receiver for receiving a radio signal transmitted from the radio signal processor;
A signal extracting unit for extracting a reference signal to be used for synchronization acquisition from the radio signal;
A synchronization signal generator for generating a synchronization signal using the reference signal;
A voltage controlled oscillator that generates an oscillation signal and corrects a phase of the generated oscillation signal by a frequency corresponding to an input reference signal or a voltage signal;
And a control unit for receiving the oscillation signal generated by the voltage control oscillator and the synchronization signal generated by the synchronization signal generation unit to compare phases of the oscillation signal and the synchronization signal and generating a voltage signal corresponding to a phase difference between the oscillation signal and the synchronization signal A phase detector for detecting the phase difference; And
A main hub unit for receiving the oscillation signal whose phase is corrected by the voltage-controlled oscillator and the radio signal received by the signal receiver, and outputting the radio signal according to the corrected oscillation signal;
And a synchronous acquisition system. The method according to claim 1,
A frequency divider for dividing an oscillation signal according to a voltage level of an oscillation signal output from the voltage control oscillator or a voltage signal generated by the phase detector to a predetermined frequency division ratio,
And a synchronous acquisition system. 3. The method of claim 2,
An analog / digital converter for converting the analog radio signal received by the signal receiver into a digital signal;
A serial-to-parallel converter for converting the digital signal converted by the analog-to-digital converter into a parallel signal; And
A fast Fourier transform unit for performing a fast Fourier transform on the digital signal converted into the parallel signal by the serial-
Further comprising: < / RTI > The method according to claim 1,
Wherein the phase detector generates a phase difference between the oscillation signal generated by the voltage controlled oscillator and the reference signal extracted by the signal extractor as the reference signal. 5. The method of claim 4,
Wherein the reference signal uses a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) as a reference signal. A method for acquiring synchronization of a repeater in a synchronization acquisition system interfacing with a radio signal processor in an environment in which a base station is separated into a digital signal processor and a radio signal processor,
Receiving a radio signal from the radio signal processor and extracting PSS and SSS as a reference signal from the radio signal;
Generating a synchronization signal based on the reference signal;
Generating an oscillation signal of the repeater itself;
Comparing the phase of the synchronization signal and the oscillation signal to correct the oscillation signal by a phase difference; And
And outputting the radio signal in accordance with the corrected oscillation signal
/ RTI > The method according to claim 6,
The step of correcting the oscillation signal comprises:
Comparing a phase of the synchronization signal and the oscillation signal to generate a voltage corresponding to the phase difference;
Generating the generated voltage as a voltage signal; And
Correcting the oscillation signal by a frequency corresponding to a voltage level of the voltage signal based on the generated voltage signal
/ RTI > 8. The method of claim 7,
Before the step of generating the voltage,
Comparing the phase of the extracted reference signal with the phase of the oscillation signal to generate a reference signal if the synchronizing signal is not input; And
Correcting the oscillation signal by a frequency corresponding to a voltage level of the voltage signal based on the reference signal
/ RTI > The method according to claim 6,
The step of generating the oscillation signal includes:
Dividing the oscillation signal by a predetermined division ratio and generating an oscillation signal of a frequency lower than the frequency of the oscillation signal generated first,
/ RTI >
KR1020120151328A 2012-12-21 2012-12-21 System and method for synchronization of relay node KR20140081501A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021006478A1 (en) * 2019-07-09 2021-01-14 에스케이텔레콤 주식회사 Apparatus and method for setting gain of radio frequency repeater by using synchronization signal

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021006478A1 (en) * 2019-07-09 2021-01-14 에스케이텔레콤 주식회사 Apparatus and method for setting gain of radio frequency repeater by using synchronization signal
US11637622B2 (en) 2019-07-09 2023-04-25 Sk Telecom Co., Ltd. Apparatus and method of setting gain of RF repeater using synchronization signal

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