Distributed antenna system for 5G specialized networks

Abstract

We provide a distributed antenna system for 5G specialized networks consisting of an Access Unit and a Remote Unit that efficiently utilizes specific frequency bands and provides high-quality communication services within buildings and specific locations. [Solution] The distributed antenna system for 5G specialized networks consists of an access unit 1 and a remote unit 5, the access unit 1 uses a frequency band of 4600 to 4900 MHz, the remote unit 5 is divided into a first type remote unit 5 that supports a frequency band of 4600 to 4800 MHz and a second type remote unit 5 that supports a frequency band of 4700 to 4900 MHz, and either the first type or the second type remote unit 5 is selected and installed depending on the location of the building.

Description

[Technical Field]

[0001] The present invention relates to a distributed antenna system for a 5G specialized network, and more particularly to a distributed antenna system for a 5G specialized network that is composed of an access unit and a remote unit for efficiently utilizing a specific frequency band and providing high-quality communication services within a building or a specific location. [Background technology]

[0002] 5G communication networks enable ultra-high-speed data transmission, ultra-low latency, and large-scale device connectivity, and are currently being used in a variety of industrial sectors. 5G specialized networks enhance security and stability by building customized communication networks for businesses and specific facilities. In such specialized networks, it is important to utilize specific frequency bands to optimize communication quality within buildings.

[0003] In conventional communication systems, when a single frequency range is used, there is a risk of communication quality being degraded due to interference within that range. To address this issue, a method is needed to effectively utilize various frequency bands, minimize interference, and achieve the best performance in each band. In particular, in communication systems based on 5G specialized networks, it is necessary for access units and remote units to cooperate and operate in specific bands, thereby optimizing the use of frequency resources and improving service quality. Summary of the Invention [Problem to be solved by the invention]

[0004] For 5G specialized network communication systems, signal transmission in various frequency bands is a key element to provide high-speed data transmission and low latency. However, in conventional communication systems, when multiple remote units operate using the same frequency band, mutual interference can occur, resulting in reduced signal quality. This interference problem can become even more serious when multiple remote units use the same frequency band in different buildings.

[0005] Furthermore, specific locations and buildings may require different frequency bands, making effective utilization of frequency resources a challenge. Conventional systems have been unable to effectively address these diverse requirements, making it difficult to efficiently manage frequency resources and provide optimized communication services. Therefore, the problem addressed by the present invention is to provide a 5G specialized network communication system that minimizes interference by dividing frequency bands between access units and remote units, providing high-quality communication services, and in particular, optimizing frequency selection to reduce interference between multiple buildings. Another problem addressed by the present invention is to propose a system that selectively supports various frequency bandwidths according to the characteristics of the building in which the remote units are installed and the needs of the company, thereby enabling flexible communication services tailored to user requests. [Means for solving the problem]

[0006] The present invention provides a 5G specialized network communication system comprising an access unit and a remote unit. In the 5G specialized network communication system of the present invention, the access unit has a frequency band of 4600-4900 MHz, and the remote units are divided into a first type of remote unit (Type A) that supports the frequency band of 4600-4800 MHz and a second type of remote unit (Type B) that supports the frequency band of 4700-4900 MHz. This configuration enables efficient utilization of frequency resources and minimization of interference by selecting and installing the appropriate type of remote unit according to the location and requirements of a building. The access unit also transmits and receives RF signals to and from a base station, converts RF signals to digital signals, and further converts the signals to optical signals. Meanwhile, the remote unit converts optical signals to digital signals and converts the digital signals back to RF signals. It includes a high-power amplifier and a noise-removing bandpass filter to ensure stable signal transmission. Furthermore, the remote unit can selectively lease bandwidths from 40 MHz to 100 MHz to provide services in response to various frequency bandwidth needs of companies. Additionally, when the remote unit is installed in a particular building, the bandwidth of the digital filter is set according to the frequency band. [Effects of the Invention]

[0007] According to an embodiment of the present invention, it is possible to provide optimized wireless services by efficiently allocating frequency bands between access units and remote units, minimizing frequency interference, and selectively installing the type of remote unit (Type A or Type B) according to the location of each building. Furthermore, when installed inside a building, the remote unit automatically recognizes the frequency band and performs frequency filtering, allowing for flexible use of various frequency bands according to the needs of the business. This prevents mutual interference while providing high-quality communication services, and efficiently utilizes frequency resources to significantly improve the stability and performance of the communication system. Furthermore, by including a control device and a power supply device that effectively control the system between the access unit and remote units, the reliability and performance of the communication system can be further ensured. This system is particularly advantageous in that it minimizes interference between buildings and provides stable service both inside and outside large buildings. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram illustrating a distributed antenna system for a 5G specialized network according to an embodiment of the present invention.

[0009] [Figure 2] FIG. 1 is a block diagram illustrating an access unit of a distributed antenna system for a 5G specialized network according to an embodiment of the present invention.

[0010] [Figure 3] FIG. 2 is a block diagram illustrating a remote unit of a distributed antenna system for a 5G specialized network according to an embodiment of the present invention.

[0011] [Figure 4] FIG. 2 is a block diagram illustrating an amplification unit of a remote unit in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention and the technical problems achieved by implementing the present invention will become more apparent from the preferred embodiments of the present invention described below. The following examples are merely illustrative for explaining the present invention and are not intended to limit the scope of the present invention.

[0013] A distributed antenna system for a 5G specialized network according to an embodiment of the present invention comprises an access unit 1 and a remote unit 5 for serving a 5G specialized network. The access unit 1 has a frequency band of 4600 to 4900 MHz, and the remote unit 5 communicating with the access unit 1 constitutes a specialized network communication system that is divided into a first type of remote unit (Type A) that supports the frequency band of 4600 to 4800 MHz and a second type of remote unit (Type B) that supports the frequency band of 4700 to 4900 MHz. With this configuration, the present invention provides flexibility in selecting and installing the type of remote unit 5 depending on the location of a building and environmental conditions.

[0014] As shown in Figure 1, the access unit 1 receives an RF signal from the base station (B), converts it into an optical signal, and transmits it to the remote unit 5 via an optical cable. The access unit 1 receives radio waves in the 4600MHz to 4900MHz band and converts them into an optical signal. The remote unit 5 receives the optical signal from the access unit 1 via the optical cable. There are two types of remote units 5: Type A, which communicates using radio waves in the 4600MHz to 4800MHz band, and Type B, which generates radio waves in the 4700MHz to 4900MHz band.

[0015] One building can be equipped with only Type A remote units 5, while another nearby building can be equipped with only Type B remote units 5. This reduces the overlapping frequency bands, reducing the possibility that radio waves generated in one building will affect other buildings and cause interference. In the 300 MHz band, except for the central overlapping 100 MHz (4700 MHz to 4800 MHz), the remaining 100 MHz (4600 MHz to 4700 MHz, 4800 MHz to 4900 MHz) can be used exclusively by each building. In this way, having shared and exclusive bands can secure a certain amount of bandwidth while reducing the possibility of interference. Exclusive bands can be used to transmit more important signals requiring high performance, while the remaining overlapping bands can be used.

[0016] Multiple remote units 5 can be connected to one access unit 1. One remote unit 5 is connected to the access unit 1 via one optical cable, and by installing multiple remote units 5, multiple remote units 5 can be connected to the access unit 1 via multiple optical cables. The remote units 5 can also be connected in a cascade system. In addition to a remote unit 5 directly connected to the access unit 1 via an optical cable, it can also be connected to another remote unit 5 and indirectly connected to the access unit 1.

[0017] The RF signal received by the access unit 1 from the base station (B) is transmitted to each remote unit 5 through an optical cable, and the remote unit 5 converts the RF signal back into an RF signal and transmits it to the user device, thereby enabling smooth communication between the base station (B) and the user device. The distributed antenna system for a 5G specialized network according to an embodiment of the present invention can deliver signals from the base station (B) to shadow areas within a building.

[0018] As shown in FIG. 2, the access unit 1 of the distributed antenna system for a 5G specialized network according to an embodiment of the present invention may include an RF module 13, a first electrical-optical conversion unit 15, a control unit 10, and a first power supply unit 19.

[0019] The RF module 13 is connected to a bandpass filter, amplifier, attenuator, etc., and appropriately adjusts the magnitude of the signal received from base station B, removes noise, and passes only radio waves in the required band. Two paths, an uplink and a downlink, are formed in the RF module 13. Bandpass filters, amplifiers, attenuators, etc. may be installed along these paths. Multiple RF modules 13 can be installed, and each of the multiple RF modules 13 is connected to each of the multiple base stations B in a one-to-one correspondence. Since the access unit 1 supports the 4600 to 4900 MHz frequency band, the bandpass filter of the RF module 13 is also configured accordingly. Since 5G communication uses a time division duplex (TDD) method, the uplink path and the downlink path are alternately enabled and disabled depending on the time.

[0020] The first electrical-to-optical conversion unit 15 is configured to convert analog RF signals received from the RF module 13 into digital signals and perform electrical-to-optical conversion in the downlink path, and convert optical signals received from the remote unit 5 into RF analog signals and transmit them to the RF module 13 in the uplink path.

[0021] The plurality of RF modules 13 can be connected to a first electrical-optical conversion unit 15. Signals input from the plurality of RF modules 13 to the first electrical-optical conversion unit 15 are combined and converted into a single optical signal. This optical signal is transmitted to a remote unit 5 connected to the access unit 1 via an optical cable 21. In the downlink path, signals from a plurality of base stations B are transmitted to the remote unit 5 through a single optical cable 21. Similarly, in the uplink path, a single optical signal is split into a plurality of RF signals by the first electrical-optical conversion unit 15 and transmitted to corresponding RF modules 13. A plurality of optical cables 21 are connected to the first electrical-optical conversion unit 15, and each optical cable 21 is connected to a corresponding remote unit 5.

[0022] The access unit 1 may include a control unit 10 and a first power supply unit 19. The control unit 10 monitors and controls the RF module 13 and the first electrical-to-optical conversion unit 15 of the access unit 1, and the first power supply unit 19 can supply power to the RF module 13 and the first electrical-to-optical conversion unit 15.

[0023] As shown in FIG. 3, the remote unit 5 of the distributed antenna system for a 5G specialized network according to an embodiment of the present invention is connected to the access unit 1 via an optical cable 21, and an optical switch 51 may be installed therein.

[0024] The optical switch 51 has four terminals connected to it, one of which is connected to an optical cable 21 connected to the access unit 1. The other is connected to an optical cable 29 connected to another remote unit 5. Therefore, a remote unit that is not directly connected to the access unit 1 can be indirectly connected to the access unit 1 via another remote unit 5 that is directly connected to it. The other terminal of the optical switch 51 can be connected to a second electrical-optical conversion unit 55 via an optical multiplexer 53.

[0025] Since the distributed antenna system for a 5G specialized network according to an embodiment of the present invention is driven in a TDD mode, the optical switch 51 can be switched to form an uplink path and a downlink path according to time. A switching signal is generated by a control unit (not shown), and the optical switch 51 can be controlled according to the timing of switching between the uplink and the downlink.

[0026] During downlink, a signal input from the access unit 1 through the optical cable 21 is supplied to the second electrical-to-optical conversion unit 55 via the optical multiplexer 53, where the optical signal is converted into an RF signal and supplied to the amplification unit 60. The second electrical-to-optical conversion unit 55 also outputs an optical signal, which is supplied to the optical cable 29 connected to another remote unit via the optical multiplexer 53 and the optical switch 51. In this way, the signal transmitted from the access unit 1 can reach the remote unit 5 directly connected to the access unit 1 and other remote units connected to that remote unit 5 via the optical cable 29.

[0027] Similarly, during uplink, an optical signal is transmitted from another remote unit connected in a cascade manner to a remote unit 5 directly connected to the access unit 1, and this optical signal is combined with the signal transmitted from the remote unit 5 directly connected to the access unit 1 and transmitted to the access unit 1 via the optical switch 51 and the optical cable 21.

[0028] The second electro-optical conversion unit 55 converts the optical signal received through the optical cable 21, optical switch 51, and optical multiplexer 53 into an RF signal and supplies it to the amplification unit 60. The RF signal generated by the second electro-optical conversion unit 55 passes through the amplification unit 60, is amplified to an appropriate strength, and is transmitted to the antenna 59 via the bandpass filter 58. The antenna 59 radiates the RF signal and transmits it to the user device. The downlink path is formed in the order of the second electro-optical conversion unit 55, the amplification unit 60, the bandpass filter 58, and the antenna 59, while the uplink path is formed in the reverse order.

[0029] The second electro-optical conversion unit 55 may be connected to a plurality of amplification units 60. A band-pass filter 58 may be installed between each amplification unit 60 and the antenna 59.

[0030] The second electro-optical conversion unit 55 can divide and transmit RF signals of different frequency bands to the multiple amplification units 60. This frequency band is limited to a range of 4600 to 4800 MHz for the A-type remote unit 5, and 4700 to 4900 MHz for the B-type remote unit 5. The bandpass filter 58 must also have a passband that matches this band range.

[0031] In the uplink path, an RF signal in the aforementioned frequency band is input to a second electro-optical conversion unit 55 via an antenna 59, a bandpass filter 58, and an amplification unit 60. The second electro-optical conversion unit 55 optically converts the multiple RF signals input from the multiple amplification units 60, combines them, and transmits them to the access unit 1 via the optical switch 51.

[0032] The remote unit 5 may include a second power supply 52 to provide power to other components.

[0033] In the downlink path, the amplification unit 60 adjusts the RF signal generated by the second electro-optical conversion unit 55 to an appropriate intensity and outputs the adjusted signal, and in the uplink path, adjusts the radio wave signal input through the antenna 59 and the bandpass filter 58 to an appropriate intensity and inputs the adjusted signal to the second electro-optical conversion unit 55. As shown in FIG. 4, the amplification unit 60 installed in the remote unit 5 may include an uplink amplifier 68, a downlink amplifier 62, a variable attenuator 69, a first switch 61, a second switch 65, a third switch 67, a circulator 63, the variable attenuator 69, and a coupling line 64.

[0034] The amplification unit 60 has an input terminal 24 that receives a signal from the second electro-optical conversion unit 55, and an output terminal 26 that outputs an RF signal to the second electro-optical conversion unit 55. It also has an input / output terminal 25 that is connected to an antenna 59. During downlink, it receives an RF signal through the input terminal 24 and outputs the signal through the input / output terminal 25. During uplink, it receives a signal through the input / output terminal 25 and outputs an RF signal through the output terminal 26.

[0035] A downlink amplifier 62, a first switch 61, and a circulator 63 are installed in the downlink path connecting the input terminal 24 to the input / output terminal 25. The circulator 63 has three terminals: radio waves input to the first terminal are output to the second terminal, radio waves input to the second terminal are output to the third terminal, and radio waves input to the third terminal are output to the first terminal. The first terminal is connected to the input terminal 24, and the second terminal is connected to the input / output terminal 25. This allows the downlink path to be properly formed.

[0036] A signal input to the second terminal from the antenna 59 and the bandpass filter 58 through the input / output terminal 25 is output via a path connected to the third terminal and the output terminal 26. This forms an uplink path. Similar to the downlink path, a second switch 65, an uplink amplifier 68, and a variable attenuator 69 can be installed in the uplink path.

[0037] Meanwhile, a third switch 67 may be installed in the uplink path. This switch is connected to a coupling line 64 connected to the uplink line. The coupling line 64 is formed to extract the signal from the downlink line and send it back to the second electro-optical conversion unit 55. The coupling line 64 forms a feedback path.

[0038] One end of the third switch 67 is connected to the output terminal 26, and the other end is connected to the line of the feedback path and the line of the uplink path. The third switch 67 is switched so as to select either the signal of the feedback path or the signal of the uplink path and output it to the output terminal 26.

[0039] According to TDD switching, during downlink, a signal input to input terminal 24 passes through the second terminal of circulator 63 and is output to input / output terminal 25. At the same time, a downlink signal extracted by coupling line 64 passes through the feedback path and is output from output terminal 26 via third switch 67. This causes the extracted downlink signal to be fed back to second electro-optical conversion unit 55. During uplink, a signal input to input / output terminal 25 is input to the second terminal of circulator 63, and is output to output terminal 26 via the third terminal, third switch 67 on the uplink path.

[0040] When the extracted downlink signal is input to the second electro-optical conversion unit 55 via the feedback path, the second electro-optical conversion unit 55 analyzes the signal and converts the downlink output signal based on the analysis result. This is to apply digital predistortion (DPD) to the downlink output signal. DPD is a technique used to correct nonlinear distortion in high-power amplifiers (HPA). It pre-distorts the input signal before sending it to the downlink amplifier 62 to compensate for the amplifier's nonlinear characteristics. During this process, distortion in the opposite direction is applied to the input signal so that the signal after passing through the amplifier is as similar as possible to the original linear signal. This reduces nonlinear distortion and improves the quality of the transmitted signal.

[0041] In the TDD downlink section, the first switch 61 is closed and a signal is transmitted to the downlink path and the feedback path. At this time, the third switch 67 connects the output terminal 26 to the feedback path. The second switch 65 is opened and the transmission of radio waves to the uplink path is blocked. Conversely, in the TDD uplink section, the first switch 61 is opened, the second switch 65 is closed, and the third switch 67 connects the output terminal 26 to the uplink path. The switches are controlled according to the TDD synchronization signal to switch between the uplink and downlink.

[0042] In theory, all signals input to the first terminal of the circulator 63 should be output to the second terminal, and all signals input to the second terminal should be output to the third terminal. However, due to the characteristics of actual analog elements, the signals may not be output completely, resulting in some radio waves leaking out. In other words, it is possible that not all signals input to the first terminal are output to the second terminal, but only a portion is output to the third terminal. In this case, if the second switch 65 is ON, the radio waves are transmitted to the uplink amplifier 68, where they are amplified as noise and may be diverted to other circuits. Therefore, rather than relying entirely on the circulator 63, it is necessary to control the first switch 61, the second switch 65, and the third switch 67. In this way, with a simple configuration including the circulator 63, the first switch 61, the second switch 65, and the third switch 67, it is possible to completely separate the uplink and downlink paths in a time-division transmission structure and also achieve DPD (digital predistortion).

[0043] Although the present invention has been described above with reference to one embodiment shown in the drawings, those skilled in the art will recognize that various modifications and equivalent alternative embodiments are possible. [Explanation of symbols]

[0044] 1: Access unit 5: Remote unit 10: Control unit 13: RF module 15: First electro-optical conversion unit 19: 1st power supply section 21: Optical cable 51: Optical switch 52: 2nd power supply section 53: Optical multiplexer 55: Second electro-optical conversion unit 58: Bandpass filter 59: Antenna 60: Amplification unit

Claims

1. In a distributed antenna system for a 5G specialized network consisting of an access unit and a remote unit, said access unit uses a frequency band of 4600-4900 MHz; The remote units are divided into a first type remote unit supporting a frequency band of 4600 to 4800 MHz and a second type remote unit supporting a frequency band of 4700 to 4900 MHz, and are configured to select and install either the first type remote unit or the second type remote unit depending on the location of a building; the access unit and the remote unit are driven in a TDD mode; the remote unit includes a second electro-optical conversion unit that converts the optical signal received from the access unit into a digital signal and further converts the digital signal into an RF signal, an amplification unit that adjusts the intensity of the RF signal, a bandpass filter that removes out-of-band noise, and an antenna that emits radio waves that have passed through the bandpass filter; The amplification unit includes: an input terminal for inputting a signal from the second electro-optical conversion unit, an output terminal for outputting an RF signal to the second electro-optical conversion unit, and an input / output terminal for connecting to the antenna; a downlink path is formed between the input terminal and the input / output terminal, and an uplink path and a feedback path are formed between the input / output terminal and the output terminal; the downlink path is provided with a downlink amplifier, a first switch, and a circulator; the circulator has a first terminal, a second terminal, and a third terminal, a radio wave input to the first terminal is output to the second terminal, a radio wave input to the second terminal is output to the third terminal, and a radio wave input to the third terminal is output to the first terminal, the first terminal is connected to the input terminal, the second terminal is connected to the input / output terminal, and the third terminal is connected to the output terminal, thereby forming the downlink path and the uplink path; the uplink path is formed as a path that passes through the input / output terminal, the second terminal and the third terminal of the circulator, and reaches the output terminal; the uplink path is provided with a second switch, an uplink amplifier, and a third switch; one end of the third switch is connected to the output terminal, and the other end is connected to a line of the feedback path and a line of the uplink path, and the third switch is switched so as to select either a signal of the feedback path or a signal of the uplink path and output the selected signal to the output terminal; the feedback path is formed so as to couple a signal from the downlink path and send it to the output terminal via the third switch; During a TDD downlink, a signal input to the input terminal is output from the input / output terminal via the second terminal, and a downlink signal passes through the third switch via the feedback path and is output from the output terminal; During a TDD uplink, a signal input to the input / output terminal is input to the second terminal of the circulator, passes through the third terminal, passes through the third switch of the uplink path, and is output from the output terminal; The downlink signal output from the output terminal via the feedback path can be used for digital pre-distortion applied in the second electro-optical conversion unit. Distributed antenna system for 5G specialized networks.

2. 2. The distributed antenna system for a 5G specialized network according to claim 1, wherein the access unit includes an RF module and a first electrical-to-optical conversion unit for transmitting and receiving RF (Radio Frequency) signals to and from a base station, converting the RF signals to digital signals, and further converting the digital signals to optical signals.

3. 2. The distributed antenna system for a 5G specialized network of claim 1, wherein the remote unit includes an optical switch connected to the access unit by an optical cable, and in a downlink path, an optical signal received on the optical cable passes through the second electrical-to-optical conversion unit and is transmitted to another remote unit through another optical cable, and in an uplink path, an optical signal from another remote unit is transmitted to the access unit through the second electrical-to-optical conversion unit, thereby connecting a plurality of remote units in a cascade manner.

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