Millimeter-wave repeater for intermediate frequency band transmission

A millimeter-wave repeater may be provided to cover a radio shaded area, in a system for the millimeter-wave repeater. The millimeter-wave repeater may provide a service by changing a signal of a millimeter-wave band to an intermediate frequency band, and then changing the signal to the millimeter-wave band again.

BACKGROUND

The disclosure relates to a millimeter-wave repeater for intermediate frequency band transmission, and a system therefor. More particularly, the disclosure relates to a millimeter-wave repeater, which provides a technology for stably maintaining a service even when there are unnecessary signal inputs, a propagation environment problem, or various installation site variables.

2. Description of the Related Art

In a millimeter-wave relay service, a millimeter-wave repeater is installed to expand a service radius and cover a radio shaded area. In a general millimeter-wave repeater, when an unnecessary signal corresponding to a frequency other than a service channel is input, an unnecessary wave other than a desired signal is also amplified, and thus a system may be damaged or service quality may deteriorate. When the system is unable to perform a function due to such a reason, another shaded area is generated.

In this regard, the disclosure provides a repeater for reducing a signal of a millimeter-wave band to an intermediate frequency band to transmit the signal, and then converting the intermediate frequency band to the millimeter-wave band again to provide a service.

In a repeater that serves a signal of a millimeter-wave band equal to or greater than 20 GHz as a 5thgeneration (5G) signal, when an unnecessary signal other than a set channel is excessively introduced to a corresponding amplification system from a millimeter frequency band relay system, it is difficult to manufacture a filter for suppressing only the unnecessary signal without affecting service quality, and the cost for manufacturing the filter is also very high. In addition, it is necessary to solve a cost issue of a cable being used for long-distance transmission of a millimeter-wave signal band.

SUMMARY

Provided is a millimeter-wave repeater capable of providing a stable millimeter-wave relay service without a change in service quality, by using a filter through which only a desired band is passed by converting a millimeter-wave frequency into an intermediate frequency, expanding a transmission distance via transmission in the intermediate frequency, and then converting the intermediate frequency into the millimeter-wave frequency.

According to one or more embodiments, a millimeter-wave repeater includes a donor input/output unit configured to separate a downlink signal and an uplink signal of a radio signal, and including a transmission output processing unit for performing low-noise amplification on an input downlink signal and transmitting an amplified signal to a donor channel filter unit, and a reception output processing unit for outputting the uplink signal input from the donor channel filter unit in an assigned level the donor channel filter unit configured to convert the downlink signal of the donor input/output unit into an intermediate frequency signal by using a frequency mixer, perform channel filtering on the intermediate frequency signal, and transmit a channel-filtered signal to a donor multiplex transmission unit, and convert the uplink signal input to the donor multiplex transmission unit into a signal of a millimeter-wave band by using the frequency mixer and transmit the signal of the millimeter-wave band to the donor input/output unit, the donor channel filter unit including a reference signal unit for generating and transmitting a reference frequency signal, the donor multiplex transmission unit including a multiplexer for coupling and transmitting the downlink signal input to the donor channel filter unit and a plurality of signals, and configured to transmit the input uplink signal to the donor channel filter unit, a transmission unit configured to transmit a signal, a server multiplex transmission unit including a downlink multi-distribution unit configured to separate, from the downlink signal input to the transmission unit, a modem signal for communication and the reference frequency signal for synchronization with a phase synchronization circuit, and an uplink transmission unit configured to transmit the uplink signal input via a server channel filter unit to the transmission unit, the server channel filter unit configured to convert an intermediate frequency downlink signal input to the server multiplex transmission unit into a signal in a millimeter-wave band by using the frequency mixer and transmit the signal in the millimeter-wave band to a server input/output unit, perform frequency mixing on an uplink frequency of the server input/output unit and convert a mixed signal into an intermediate frequency, and perform channel filtering on a converted signal and transmit a filtered signal to the server multiplex transmission unit, the server input/output unit including a transmission output processing unit configured to output the downlink signal output from the server channel filter unit in an assigned level, and a reception output processing unit configured to perform low-noise amplification on the uplink signal and transmit an amplified signal to the server channel filter unit, and a power supply unit configured to perform a function of supplying power.

The donor input/output unit may be configured to support an antenna having a 2×2 multi-input multi-output (MIMO) structure. The server channel filter unit may include the phase synchronization circuit using the reference frequency signal of the reference signal unit of the donor channel filter unit. The millimeter-wave repeater may further include a control unit configured to monitor and control an operation state of the millimeter-wave repeater by monitoring an output level for each channel of the donor input/output unit and server input/output unit, and processing a level for each channel to be output in a uniform level.

The control unit may adjust a final gain by attenuating a gain of one of the donor multiplex transmission unit and server multiplex transmission unit, by using output level information of the downlink signal and output level information of the uplink signal. The power supply unit may be configured to transmit information related to normality of power supply to the control unit. The donor multiplex transmission unit and the server multiplex transmission unit may each include a band signal equalizer for compensating for frequency attenuation. The donor multiplex transmission unit and the server multiplex transmission unit may each include a variable gain adjustment device for uniformly maintaining attenuation according to a length of a transmission path.

DETAILED DESCRIPTION

Hereinafter, embodiments of the disclosure will be described in detail with reference to the accompanying drawings such that one of ordinary skill in the art may easily implement the disclosure. However, the disclosure may be implemented in various different forms and is not limited to embodiments described herein. In the drawings, parts irrelevant to the description are omitted to clearly describe embodiments of the disclosure.

Also, the terms used in the present specification are only used to describe specific embodiments, and are not intended to limit the disclosure. An expression used in the singular may encompass the expression in the plural, unless it has a clearly different meaning in the context.

Further, components shown in embodiments of the disclosure are independently illustrated to represent different characteristic functions, and it does not mean that the components are formed in units of separate pieces of hardware or single piece of software. In other words, the components are described by listing the components for convenience of description, and at least two components may form one component or one component may be divided into a plurality of components to perform a function. An integrated embodiment and separated embodiments of each component are also included in the scope of the disclosure unless deviated from the essence of the disclosure.

FIG.1is a diagram of a downlink signal configuration of a general millimeter-wave repeater11, wherein a signal input from a gNodeB (gNB)10through an antenna is transmitted to a remote place via transmission unit23after a frequency is separated via a donor input/output unit21, and an assigned frequency is transmitted and a gain is adjusted via a donor channel filter unit22, and is emitted to a terminal20via a server input/output unit27by passing through a server channel filter unit26and adjusting the gain. An uplink signal input through the terminal20is transmitted to the transmission unit23after low-noise amplification via the server input/output unit27and filtering via the server channel filter unit26, and an uplink signal input through the transmission unit23is emitted through an antenna after gain adjustment via the donor channel filter unit22and amplification via the donor input/output unit21. The gNB10receives the emitted signal and provides a service. Power supply units24and28are respectively positioned at a donor and a server, and control units25and29are also respectively positioned at the donor and the server.

As shown inFIG.1, a signal flow in the general millimeter-wave repeater11has a limitation of a transmission distance because the signal emitted from the gNB10is transmitted in a millimeter-wave band.

FIG.2is a diagram of a configuration of a millimeter-wave repeater, according to an embodiment of the disclosure.

To overcome the limitation of the transmission distance in the millimeter-wave band, when a downlink signal in a millimeter-wave band input from the gNB10is input to a donor input/output unit1, according to an embodiment of the disclosure inFIG.2, the downlink signal is input to a circulator101ofFIG.3A, an uplink signal is separated via a switch102for a low-noise amplifier103and is transmitted to a donor channel filter unit2via a signal separation switch104. Regarding an uplink signal input to the donor channel filter unit2, only the uplink signal is input to the signal separation switch104, an image signal and an unnecessary wave of the uplink signal are removed via a band pass filter105, the uplink signal is amplified via an amplifier106, an isolator107, and a high-output amplifier108, input to the circulator101via a coupler109for signal detection, and is emitted to the gNB10through the antenna. Referring toFIG.3A, the donor input/output unit1may be configured to support an antenna of a 2×2 multi-input multi-output (MIMO) structure.

UnlikeFIG.3A,FIG.3Billustrates a configuration in which a downlink antenna and an uplink antenna are separately used. A downlink signal input to a donor antenna215is amplified via a low-noise amplifier103via a switch102, and transmitted to the donor channel filter unit2via a signal separation switch104. Regarding an uplink signal input to the donor channel filter unit2, only the uplink signal is input to the signal separation switch104, an image signal and an unnecessary wave of the uplink signal are removed via a band pass filter105, the uplink signal is amplified via an amplifier106, an isolator107, and a high-output amplifier108, input to a server antenna216via a coupler109for signal detection, and is emitted to the gNB10through the antenna.

FIG.4is a diagram of a configuration of the donor channel filter unit2among the configuration of the millimeter-wave repeater, according to an embodiment of the disclosure.

Referring toFIG.4, a downlink signal in a millimeter-wave band transmitted to the donor input/output unit1is converted into an intermediate frequency via a signal synthesizer202after an unnecessary wave is filtered via a band pass filter201. The converted intermediate frequency passes through a low-band pass filter203, passes through high-performance band pass filters205through208via an N:1 switch204, and then is transmitted to a donor multiplex transmission unit3via a 1:N switch209. An uplink signal in an intermediate frequency input to the donor multiplex transmission unit3passes through the high-performance band pass filters205through208via the 1:N switch209and is transmitted to the signal synthesizer202via the N:1 switch204and the low-band pass filter203. The uplink signal is converted into a signal in a millimeter-wave band via the signal synthesizer202, and is transmitted to the donor channel filter unit2via an image filter removing filter201. The donor channel filter unit2may include a reference signal unit211for generating and transmitting a reference frequency signal, and the signal synthesizer202inputs the reference frequency signal generated by the reference signal unit211to a phase synchronization circuit210and generates the intermediate frequency by synthesizing the reference frequency signal with a sum (+) or subtraction (−) signal of an output signal of the phase synchronization circuit210and an input millimeter-wave signal.

FIG.5is a diagram of a configuration of the donor multiplex transmission unit3among the configuration of the millimeter-wave repeater, according to an embodiment of the disclosure.

Referring toFIG.5, a downlink signal input to the donor multiplex transmission unit3after being converted into an intermediate frequency is amplified via an amplifier301, passes through a variable gain adjustment device302, passes through a low-frequency band pass filter303, passes through a coupler304for detecting an output signal, passes through a downlink-uplink separation switch306, is combined with a reference frequency signal310and a communication signal311for communication with a server at a multi-transmission coupler309via a band signal equalizer device307, and is transmitted to a transmission unit4. For 5thgeneration (5G) time division duplex (TDD) signal analysis, a synchronization detection signal308may be used by being transmitted to a signal path. An uplink signal input through the transmission unit4is input to the multi-transmission coupler309, passes through the band signal equalizer device307, passes through the downlink-uplink separation switch306for signal separation, passes through an amplifier312for gain amplification, passes through a coupler313for input signal detection, passes through a variable gain adjustment device315for gain adjustment, passes through an amplifier316for gain amplification, and is transmitted to the donor channel filter unit2.

FIG.6is a diagram of a configuration of a server multiplex transmission unit5among the configuration of the millimeter-wave repeater, according to an embodiment of the disclosure.

Referring toFIG.6, a downlink signal of the donor multiplex transmission unit3input via the transmission unit4is divided into a reference frequency signal403, a communication signal404for communication with a server, a synchronization signal402, and a downlink/uplink signal via a multi-signal distributor401of the server multiplex transmission unit5, and the downlink signal passes through an amplifier412after signal separation via a gain adjustment device405and a signal separation switch406, passes through a coupler413for input signal detection, passes through a variable gain device414and an amplifier415for gain amplification, and is transmitted to a server channel filter unit6. Regarding an uplink signal, a signal input to the server channel filter unit6is amplified via an amplifier410, passes through a variable gain adjustment device409for suitable gain adjustment, passes through a low-band pass filter408, a coupler407for output signal detection, the signal separation switch406, and the gain adjustment device405to be input to the multi-signal distributor401, and is transmitted to the transmission unit4.

FIG.7is a diagram of a configuration of the server channel filter unit6among the configuration of the millimeter-wave repeater, according to an embodiment of the disclosure.

A downlink signal input to the server multiplex transmission unit5ofFIG.7passes through high-performance band pass filters502through505via a 1:N switch501, is transmitted to a signal separation switch506via an N:1 switch506, is converted into a millimeter-wave signal via a signal synthesizer508via a low-band pass filter507, and is transmitted to a server input/output unit7via a band pass filter509. An uplink signal input to the server input/output unit7passes through the band pass filter509for unnecessary wave filtering, and is converted into an intermediate frequency via the signal synthesizer508. The intermediate frequency passes through the low-band pass filter507, passes through the high-performance band pass filters502through505via the N:1 switch506, and then is transmitted to the server multiplex transmission unit5via the 1:N switch501. The server channel filter unit6may include a server reference signal unit510and a server phase synchronization circuit511using a same frequency as the reference frequency signal generated by the reference signal unit211of the donor channel filter unit2.

FIG.8is a diagram of a configuration of the server input/output unit7among the configuration of the millimeter-wave repeater, according to an embodiment of the disclosure.

Regarding a downlink signal input to the server channel filter unit6, only the downlink signal is input to the signal separation switch104, an image signal and an unnecessary wave of the downlink signal are removed via a band pass filter610, the downlink signal is amplified via an amplifier609, an isolator608, and a high-output amplifier607, input to a circulator604via a coupler605for signal detection, and is emitted to the terminal20through the antenna. Regarding an input signal input to the terminal20, only the uplink signal is input to a downlink-uplink separation switch603and is transmitted to the server channel filter unit6via a low-noise amplifier602and a signal separation switch601.

Regarding monitoring and controlling of a downlink signal, when an input of an input signal is higher than a rated level by A, output level information of an intermediate frequency downlink output detector305or606is monitored by control unit9aor9b, determined to be higher by A, and output after the variable gain adjustment device302or the variable gain device414attenuates and adjusts a gain by A. Regarding monitoring and controlling of an uplink signal, when an input of an input signal is higher than a rated level by A, output level information of an intermediate frequency downlink output detector411or110is monitored by the control unit9aor9b, determined to be higher by A, and output after the variable gain adjustment device409or315attenuates and adjusts a gain by A.

In detail, referring to the signal flow, when a signal input in a service signal level −60 dBm is amplified by a gain 50 dB via the donor input/output unit1under the same condition as above, the signal exceeds a standard of an output limit level −20 dBm of the donor multiplex transmission unit3(−10 dBm is output as an input level −60 dBm is amplified to total 50 dB in the donor input/output unit1, the donor channel filter unit2, and the donor multiplex transmission unit3), and thus the control unit9acontrols a gain of the donor multiplex transmission unit3such that a final gain is adjusted to 40 dB, thereby outputting −20 dBm. Then, a −30 dBm signal lowered by −10 dB via the transmission unit4gains total 50 dB via the server multiplex transmission unit5, the server channel filter unit6, and the server input/output unit7, and thus is output in a system output signal level 20 dBm. An uplink input/output configuration is similar to the downlink input/output configuration, and thus details thereof are not provided again.

FIG.9is a diagram of an automatic gain control (AGC) operation of a general millimeter-wave repeater.

Referring toFIG.9, in a case of envelope detection method or another detection method in the downlink output detector305using an output level adjustment method via general automatic gain adjustment, a 5G signal or a TDD service signal repeats on/off or is shaken in cycles within several us in a time domain, and time is consumed for a gain automatic adjustment function of an amplification unit to detect an output level of the 5G signal or TDD service signal and then adjust a gain thereof. Accordingly, when gain adjustment is performed based on inaccurate output level information while it is difficult to immediately and accurately detect an output, the output is unable to be maintained uniform and greater output level distortion may be aggravated. As shown inFIG.10, a difference is generated between an actual output signal gain and a desired rated output gain in a service signal situation in which a signal input is repeated fluctuatively at short time cycles in the time domain, and when automatic gain adjustment is performed to compensate for the difference, a difference between a level detection time point and a gain adjustment performance time point is generated, and thus a distorted output level far from a desired output level is output to a system. In a section where there is no signal, level information of the downlink output detector606indicates a low value and the control unit9aor9bincreases a gain by a difference between the desired output level and a level indicated by the downlink output detector606. At this time, when an input is suddenly provided and an abnormal fluctuating signal is input to the switch102, over-output occurs. In terms of a time axis, an unstable output is emitted and thus service quality is deteriorated, and in particular, components are damaged in an over-output situation.

FIG.10is a diagram of an automatic level control (ALC) operation of the millimeter-wave repeater, according to an embodiment of the disclosure.

Referring toFIG.10, an automatic level output method of the millimeter-wave repeater, according to an embodiment of the disclosure, is shown. When a signal input from the gNB10via the antenna is output at the server input/output unit7via the donor input/output unit1and reaches an output level set via the control units9aand9bof the downlink output detector305of the donor multiplex transmission unit3and the downlink output detector606, a signal higher than a rated output level is adjusted by the variable gain adjustment devices302and the variable gain device414such that an over-output is prevented from being emitted via the circulator604. Also, even when a fluctuating signal is input, a stable service may be provided by decreasing an overall gain change and output change of a system in a time domain only when the fluctuating signal is equal to or greater than a certain level, instead of adjusting a gain all the time as inFIG.9.

The control units25and29includes temperature detection units, may adjust gains of downlink and uplink signals by using information of the intermediate frequency downlink output detector110, a level detection unit314, a level detection unit416, and the downlink output detector606, control the server phase synchronization circuit511of the signal synthesizer508to synthesize an assigned frequency by using a signal of the reference signal unit211as a signal of the server phase synchronization circuit511via a transmission path, control channel settings of the donor channel filter unit2and the server channel filter unit6to set frequencies and channel widths for each channel, perform controls for normalization processing via information transmitted from the intermediate frequency downlink output detector110, the level detection unit314, the level detection unit416, and the downlink output detector606, and identify and monitor determined frequency information and temperature detection of an amplifier.

Also, the power supply units24may supply power to each component inside the millimeter-wave repeater and provide information about normality of power supply, to the control units25and29.

According to the disclosure, a signal in a millimeter-wave band can be remotely relayed without deterioration of signal quality.

According to the disclosure, a millimeter-wave repeater for intermediate frequency band transmission can be provided by using a donor multiplex transmission unit and a server multiplex transmission unit.

The effects of the disclosure are not limited to those mentioned above, and other effects that are not mentioned may be clearly understood by one of ordinary skill in the art from the detailed description.