Repeater and communication system

Abstract

The utility model discloses a repeater and a communication system, and relates to the technical field of communication. The repeater comprises a near-end machine and a plurality of far-end machines, wherein each far-end machine comprises a first signal transceiving module; the input end of the low-noise amplifier is connected with the output end of the first signal transceiving module; the input end of the frequency selection module is connected with the output end of the low-noise amplifier; the input end of the analog-to-digital module is connected with the output end of the frequency selection module; the input end of the down-conversion module is connected with the output end of the analog-to-digital module; the input end of the power regulation module is connected with the output end of the down-conversion module; and the input end of the digital signal-to-optical signal module is connected with the output end of the power regulation module, and the output end of the digital signal-to-optical signal module is connected with a next-stage far-end machine or a next-stage near-end machine. According to the repeater, the signal coverage range can be expanded, the signal transmission quality can be improved, and uplink channel blockage can be avoided.

Description

Technical Field

[0001] This utility model relates to the field of communication technology, and in particular to a repeater and communication system. Background Technology

[0002] In environments such as large buildings, traffic tunnels, and basements, there are signal blind spots that radio base stations cannot cover, resulting in poor signal and inability to communicate, which affects users' communication needs.

[0003] To cover these blind spots, repeaters are commonly used to supplement coverage. Repeaters can ensure network coverage without increasing the number of base stations, and their cost is far lower than that of microcell systems with the same effect. Repeaters typically consist of a near-end unit and a far-end unit. Traditional repeaters use fiber optic cables to transmit radio frequency signals from the near-end unit to the far-end unit, which then converts the digital signal back to radio frequency. If the indoor environment is large and the distance between the near-end and far-end units is significant, problems such as decreased signal-to-noise ratio due to optical signal attenuation, poor signal transmission quality, and reduced timing accuracy can occur. Furthermore, when a mobile terminal is too close to the far-end unit, causing excessive signal power received by the far-end unit, uplink congestion can occur, preventing other mobile terminals from accessing the network. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a repeater and system that can improve the signal coverage of the repeater, enhance signal transmission quality, and avoid uplink path congestion.

[0005] On one hand, the repeater according to an embodiment of the present invention includes a near-end unit and multiple far-end units. The multiple far-end units form multiple transmission links. Each transmission link includes several far-end units cascaded together. The far-end unit closest to the near-end unit in each transmission link is connected to the near-end unit via an optical fiber. The far-end unit includes:

[0006] First signal transceiver module;

[0007] A low-noise amplifier, the input of which is connected to the output of the first signal transceiver module;

[0008] The frequency selection module has its input terminal connected to the output terminal of the low-noise amplifier;

[0009] An analog-to-digital converter has its input terminal connected to the output terminal of the frequency selection module;

[0010] The input terminal of the downconverter module is connected to the output terminal of the analog-to-digital converter module;

[0011] The power regulation module has its input terminal connected to the output terminal of the down-converter module.

[0012] The digital signal to optical signal module has its input end connected to the output end of the power adjustment module, and its output end is connected to the next-level remote unit or the near-end unit.

[0013] According to some embodiments of the present invention, the proximal end device includes:

[0014] The input end of the optical signal receiving module is connected to the output end of the digital signal to optical signal module of the remote unit closest to each of the transmission links;

[0015] The input terminal of the upconversion module is connected to the output terminal of the optical signal receiving module;

[0016] The input terminal of the digital-to-analog converter is connected to the output terminal of the upconverter module.

[0017] The second signal transceiver module has its input terminal connected to the output terminal of the digital-to-analog module.

[0018] According to some embodiments of the present invention, the second signal transceiver module includes a coupler and a duplexer connected to each other, and the near-end unit further includes:

[0019] The filter module has its input end connected to the output end of the duplexer;

[0020] The digital processing module has its input terminal connected to the output terminal of the filtering module;

[0021] The optical transceiver module has its input end connected to the output end of the digital processing module, and the optical transceiver module is connected to the far end unit that is closest to the near end unit in each of the transmission links.

[0022] According to some embodiments of the present invention, the far-end unit closest to the near-end unit in each transmission link further includes:

[0023] The optical module has its input end connected to the output end of the optical transceiver module of the near-end unit;

[0024] The signal processing module has its input end connected to the output end of the optical module;

[0025] The power amplifier module has its input terminal connected to the output terminal of the signal processing module, and its output terminal connected to the input terminal of the first signal transceiver module.

[0026] According to some embodiments of the present invention, the power regulation module includes:

[0027] The power acquisition unit is used to acquire the power information of the digital signal after it has been down-converted by the down-conversion module;

[0028] A power comparison unit is used to compare the power information of the digital signal with a preset power range to obtain a comparison result;

[0029] A power adjustment unit is used to adjust the power of the digital signal based on the comparison result.

[0030] According to some embodiments of the present invention, the power regulation unit includes:

[0031] Controller;

[0032] A power amplifier, connected to the controller, is used to amplify the power of the digital signal when the comparison result indicates that the power information is less than the minimum value of the preset power range.

[0033] A power attenuator, connected to the controller, is used to attenuate the power of the digital signal when the comparison result indicates that the power information is greater than the maximum value of the preset power range.

[0034] According to some embodiments of the present invention, the repeater also includes a satellite timing module, which is used to synchronize the time of the near-end unit and the far-end unit.

[0035] According to some embodiments of the present invention, the housings of the near-end unit and the far-end unit are made of die-cast aluminum alloy, and a heat-conducting metal plate is provided inside the housing.

[0036] According to some embodiments of the present invention, the frequency selection module includes a surface acoustic wave filter or a cavity filter.

[0037] On the other hand, the communication system according to the present invention includes the repeater described in the above embodiments.

[0038] The repeater and communication system according to embodiments of this utility model have at least the following beneficial effects: By setting up multiple transmission links, each with multiple cascaded remote units, the repeater can cover more signal blind spots, amplify the signal step by step and extend it to a farther area, achieving continuous coverage, breaking through the transmission distance limitations of a single device, and flexibly deploying nodes according to terrain requirements to eliminate signal blind spots as much as possible. Simultaneously, multiple remote units can process signals of different frequency bands separately, achieving multi-service converged coverage. The remote units, through low-noise amplifiers and frequency selection modules, can reduce the noise figure, improve signal acquisition capability, and accurately extract the target frequency band from the received radio frequency signals; the power adjustment module performs real-time power adjustment of the signal, thereby avoiding uplink path congestion and preventing the near-end unit from failing to accurately acquire the signal sent by the remote unit.

[0039] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0040] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0041] Figure 1 This is a schematic diagram of the repeater station according to an embodiment of the present utility model;

[0042] Figure 2 This is a schematic diagram of the structure of the remote unit in an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the near-end unit of an embodiment of the present invention. Detailed Implementation

[0044] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0045] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0046] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this utility model are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0047] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] This utility model provides a repeater and communication system. By setting up multiple transmission links, each with multiple cascaded remote units, the repeater can cover more signal blind spots. It can amplify the signal step-by-step and extend it to a farther area, achieving continuous coverage and breaking through the transmission distance limitations of a single device. It also allows for flexible deployment of nodes according to terrain requirements, minimizing signal blind spots. Simultaneously, multiple remote units can process signals of different frequency bands, achieving multi-service converged coverage. The remote units, through low-noise amplifiers and frequency selection modules, can reduce the noise figure, improve signal acquisition capability, and accurately extract the target frequency band from the received RF signal. A power adjustment module performs real-time power adjustment of the signal, thereby avoiding uplink path congestion and ensuring that the near-end unit can accurately acquire the signal transmitted by the remote unit.

[0049] The repeater and communication system of the present application embodiments are described in detail below with reference to the accompanying drawings.

[0050] On the one hand, such as Figure 1As shown, this utility model embodiment proposes a repeater, including a near-end unit 100 and multiple far-end units 200. The multiple far-end units 200 constitute multiple transmission links, and each transmission link includes several far-end units 200 cascaded together. The far-end unit 200 closest to the near-end unit 100 in each transmission link is connected to the near-end unit 100 via optical fiber; as shown... Figure 2 As shown, the remote unit 200 includes: a first signal transceiver module 210, a low-noise amplifier 220, a frequency selection module 230, an analog-to-digital converter 240, a down-conversion module 250, a power adjustment module 260, and a digital signal to optical signal converter 270; wherein, the output terminal of the first signal transceiver module 210 is connected to the input terminal of the low-noise amplifier 220, the output terminal of the low-noise amplifier 220 is connected to the input terminal of the frequency selection module 230, the output terminal of the frequency selection module 230 is connected to the input terminal of the analog-to-digital converter 240, the output terminal of the analog-to-digital converter 240 is connected to the input terminal of the down-conversion module 250, the output terminal of the down-conversion module 250 is connected to the input terminal of the power adjustment module 260, the output terminal of the power adjustment module 260 is connected to the input terminal of the digital signal to optical signal converter 270, and the output terminal of the digital signal to optical signal converter 270 is connected to the next-level remote unit 200 or near-end unit 100.

[0051] Specifically, the remote unit 200 can acquire the signal from the mobile terminal through the first signal transceiver module 210, and then amplify the radio frequency signal received by the first signal transceiver module 210 through the low noise amplifier 220 to reduce the noise figure, thereby improving the signal acquisition capability of the remote unit 200 and ensuring that subsequent modules can effectively analyze the signal of the mobile terminal. The radio frequency signal amplified by the low noise amplifier 220 is transmitted to the frequency selection module 230 for frequency selection, thereby accurately extracting the target frequency band (such as the 5G frequency band or FM broadcast frequency band allocated by a specific operator) from the received radio frequency signal, thereby supporting independent frequency selection of multiple frequency bands (such as simultaneous compatibility with 2G / 3G / 4G signals) and improving the system coverage flexibility. The frequency-selected radio frequency signal is sent to the analog-to-digital converter 240 for analog-to-digital conversion, converting the analog signal into a digital signal for subsequent signal processing. The digital signal is sent to the down-conversion module 250, which down-converts the digital signal to an intermediate frequency signal or baseband signal for subsequent digital processing and to improve the stability of signal transmission. The down-converted digital signal is transmitted to the power adjustment module 260. The power adjustment module 260 detects the power of the digital signal and reduces it when the power is too high to prevent uplink path congestion caused by excessive signal power. Simultaneously, the power adjustment module 260 can also increase the signal power when the power is too low, facilitating signal reception and processing by the near-end unit 100 and ensuring signal transmission stability. Finally, the digital signal, after power adjustment by the power adjustment module 260, is sent to the digital-to-optical signal conversion module 270, which converts the digital signal into an optical signal. This optical signal is then transmitted to the near-end unit 100 via optical fiber, or sequentially through the remote unit 200 in the transmission link before being transmitted to the near-end unit 100, thus completing the uplink signal transmission between the remote unit 200 and the near-end unit 100.

[0052] According to the repeater of this utility model embodiment, by setting up multiple transmission links, and each transmission link having multiple cascaded remote units 200, the repeater can cover more signal blind spots, amplify the signal step by step and extend it to more distant areas (such as subway tunnels, highways, etc.), achieve continuous coverage, break through the transmission distance limitation of a single device, and flexibly deploy nodes according to terrain requirements to eliminate signal blind spots as much as possible. At the same time, multiple remote units 200 can process signals of different frequency bands (such as FM broadcast and 4G / 5G signal parallel transmission), realizing multi-service converged coverage. The remote units 200, through low-noise amplifiers 220 and frequency selection modules 230, can reduce the noise figure, improve signal acquisition capability, and accurately extract the target frequency band from the received radio frequency signal; through power adjustment modules 260, the signal power is adjusted in real time, thereby avoiding uplink path congestion and preventing the near-end unit 100 from failing to accurately obtain the optical signal sent by the remote unit 200.

[0053] In some embodiments of this application, the first signal transceiver module 210 may include a donor antenna and a duplexer. The donor antenna receives uplink signals (such as radio frequency signals transmitted by a mobile terminal within the coverage area) and can also transmit radio frequency signals. The donor antenna is directly connected to the receiver (RX) and transmitter (TX) of the duplexer via a radio frequency feeder, forming a complete transceiver link. The duplexer uses an internal filter to achieve frequency band isolation between uplink and downlink signals (e.g., 900MHz uplink / 950MHz downlink) to prevent mutual interference between transmitted and received signals.

[0054] In some embodiments of this application, the frequency selection module 230 includes a surface acoustic wave (SAW) filter or a cavity filter. The SAW filter uses SAW generated by the piezoelectric effect to precisely select the target frequency band (such as the 4G / 5G band), exhibiting low insertion loss and high out-of-band rejection characteristics. The cavity filter, based on a metal resonant cavity structure, provides a high Q value (quality factor) and high isolation.

[0055] In some embodiments of this application, the power adjustment module 260 includes a power acquisition unit, a power comparison unit, and a power adjustment unit. The power acquisition unit acquires the power information of the digital signal after down-conversion by the down-conversion module 250. The power comparison unit compares the power information of the digital signal with a preset power range to obtain a comparison result. The power adjustment unit adjusts the power of the digital signal based on the comparison result. The power acquisition unit can be implemented using a multiplier or a power meter / FPGA / DSP, etc., to obtain the power of the digital signal. The power comparison unit can be implemented using a window comparator to detect whether the power of the digital signal is between two thresholds of the preset power range. If the power of the digital signal exceeds the preset power range, the power adjustment unit needs to adjust it.

[0056] In some embodiments of this application, the power adjustment unit includes a controller, a power amplifier, and a power attenuator. The controller is connected to both the power amplifier and the power attenuator. The power amplifier amplifies the digital signal when the power information represented by the comparison result is less than the minimum value of a preset power range. The power attenuator attenuates the digital signal when the power information represented by the comparison result is greater than the maximum value of the preset power range. Specifically, after obtaining the comparison result, the power comparison unit sends it to the controller. The controller controls the power amplifier or the power attenuator to operate according to the comparison result. When the power information of the digital signal is lower than the preset power range, the power amplifier is controlled to amplify the power. When the power information of the digital signal exceeds the preset power range, the power attenuator is controlled to attenuate the power. This prevents uplink path blockage caused by excessive signal power and avoids signal reception and processing difficulties for the near-end unit 100 due to insufficient power, thus affecting signal transmission stability.

[0057] In some embodiments of this application, the digital signal to optical signal module 270 includes a laser, a driving circuit, and an optical interface. The driving circuit drives the laser to convert the digital signal into an optical signal, which is then transmitted to the near-end unit 100 through the optical interface and optical fiber.

[0058] like Figure 3 As shown, in some embodiments of this application, the near-end unit 100 includes an optical signal receiving module 110, an up-conversion module 120, a digital-to-analog module 130, and a second signal transceiver module 140; wherein, the input terminal of the optical signal receiving module 110 is connected to the output terminal of the digital-to-optical signal module 270 of the far-end unit 200 closest in each transmission link, the output terminal of the optical signal receiving module 110 is connected to the input terminal of the up-conversion module 120, the output terminal of the up-conversion module 120 is connected to the input terminal of the digital-to-analog module 130, and the output terminal of the digital-to-analog module 130 is connected to the input terminal of the second signal transceiver module 140. Specifically, the optical signal receiving module 110 may include a photodetector, etc., for receiving optical signals sent by the remote unit 200 through optical fiber and converting the optical signals into digital electrical signals; the up-conversion module 120 performs digital up-conversion processing on the digital electrical signals to up-convert the signals to the target frequency band; the digital-to-analog module 130 converts the digital signals of the target frequency band into analog signals, and then transmits the analog signals outward through the second signal transceiver module 140.

[0059] In this example, the second signal transceiver module 140 includes a coupler and a duplexer connected to each other. The duplexer sends analog signals to the coupler, which then transmits them to the base station. It should be noted that the first signal transceiver module 210, low-noise amplifier 220, frequency selection module 230, analog-to-digital converter 240, down-conversion module 250, power adjustment module 260, digital-to-optical converter 270 of the remote unit 200, and the optical signal receiving module 110, up-conversion module 120, digital-to-analog converter 130, and second signal transceiver module 140 of the near-end unit 100 constitute an uplink path. The remote unit 200 acquires the signal from the mobile terminal, processes it, and sends it to the near-end unit 100, which then transmits it to the base station.

[0060] Furthermore, such as Figure 3 As shown, in some embodiments of this application, the near-end unit 100 further includes a filtering module 150, a digital processing module 160, and an optical transceiver module 170. The input terminal of the filtering module 150 is connected to the output terminal of the duplexer of the second signal receiving module 140, the input terminal of the digital processing module 160 is connected to the output terminal of the filtering module 150, the input terminal of the optical transceiver module 170 is connected to the output terminal of the digital processing module 160, and the optical transceiver module 170 is connected to the far-end unit 200 that is closest to the near-end unit 100 in each transmission link. After receiving the radio frequency signal output by the base station via a coupler, the near-end unit 100 sends it to a duplexer, which separates the uplink and downlink signals of the base station. The downlink signal enters the filtering module 150. After filtering, the signal is sent to the digital processing module 160, which may include a downconversion processor and an analog-to-digital converter. The digital processing module 160 performs downconversion and analog-to-digital conversion on the signal to obtain a downconverted digital signal. The digital signal is then sent to the optical transceiver module 170, converted into an optical signal, and sent to the remote unit 200. Through the above process, the near-end unit 100 can acquire the radio frequency signal of the base station, convert it into an optical signal, and send it to the remote unit 200.

[0061] Furthermore, such as Figure 2As shown in some embodiments of this application, the far-end unit 200 closest to the near-end unit 100 in each transmission link further includes an optical module 280, a signal processing module 290, and a power amplifier module 300. The input terminal of the optical module 280 is connected to the output terminal of the optical transceiver module 170 of the near-end unit 100, the input terminal of the signal processing module 290 is connected to the output terminal of the optical module 280, the input terminal of the power amplifier module 300 is connected to the output terminal of the signal processing module 290, and the output terminal of the power amplifier module 300 is connected to the input terminal of the first signal transceiver module 210. Specifically, the optical module 280 receives the optical signal sent by the near-end unit 100, converts it into an electrical signal, and sends the electrical signal to the signal processing module 290. The signal processing process of the signal processing module 290 is the reverse of the signal processing process of the digital processing module 160. The signal processing module 290 may include an up-converter and a digital-to-analog converter to perform up-conversion and digital-to-analog conversion on the signal to obtain an analog signal in the required frequency band. After the power amplifier module 300 amplifies the analog signal, it transmits it outward through the first signal transceiver module 210, thereby sending the signal to the target area. Finally, the base station signal is efficiently extended to the coverage area. By combining digital processing and power amplifier technology, the communication quality and coverage range are significantly improved.

[0062] Furthermore, in some embodiments of this application, the repeater also includes a satellite timing module, which is used to synchronize the transmission link. The satellite timing module receives satellite signals such as GPS / BeiDou to provide the repeater with a high-precision time reference (typically reaching nanosecond levels), ensuring strict synchronization of signal processing and forwarding operations between the near-end unit 100 and the far-end unit 200, and avoiding signal distortion or interference due to timing deviations.

[0063] Furthermore, in some embodiments of this application, the housings of the near-end unit 100 and the far-end unit 200 are made of die-cast aluminum alloy, and a heat-conducting metal plate is provided inside the housing. The die-cast aluminum alloy housing has the advantages of low density, light weight but high mechanical strength, making it suitable for frequent movement and with a long service life. At the same time, the die-cast aluminum alloy housing has high thermal conductivity, which, together with the heat-conducting metal plate, can quickly dissipate heat from the near-end unit 100 and the far-end unit 200, ensuring the normal operation of the near-end unit 100 and the far-end unit 200.

[0064] On the other hand, this utility model embodiment also proposes a communication system including the above-mentioned repeater, thereby improving signal coverage and ensuring the stability of signal transmission.

[0065] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A repeater, characterized by comprising: The system includes a near-end unit and multiple far-end units. The far-end units form multiple transmission links. Each transmission link includes several cascaded far-end units. The far-end unit closest to the near-end unit in each transmission link is connected to the near-end unit via optical fiber. Each far-end unit includes: First signal transceiver module; A low-noise amplifier, the input of which is connected to the output of the first signal transceiver module; The frequency selection module has its input terminal connected to the output terminal of the low-noise amplifier; An analog-to-digital converter has its input terminal connected to the output terminal of the frequency selection module; The input terminal of the downconverter module is connected to the output terminal of the analog-to-digital converter module; The power regulation module has its input terminal connected to the output terminal of the down-converter module. The digital signal to optical signal module has its input end connected to the output end of the power adjustment module, and its output end is connected to the next-level remote unit or the near-end unit.

2. The repeater of claim 1, wherein The near-end unit includes: The input end of the optical signal receiving module is connected to the output end of the digital signal to optical signal module of the remote unit closest to each of the transmission links; The input terminal of the upconversion module is connected to the output terminal of the optical signal receiving module; The input terminal of the digital-to-analog converter is connected to the output terminal of the upconverter module. The second signal transceiver module has its input terminal connected to the output terminal of the digital-to-analog module.

3. The repeater of claim 2, wherein The second signal transceiver module includes a coupler and a duplexer connected to each other, and the near-end unit also includes: The filter module has its input end connected to the output end of the duplexer; The digital processing module has its input terminal connected to the output terminal of the filtering module; The optical transceiver module has its input end connected to the output end of the digital processing module, and the optical transceiver module is connected to the far end unit that is closest to the near end unit in each of the transmission links.

4. The repeater of claim 3, wherein The far end unit closest to the near end unit in each of the aforementioned transmission links also includes: The optical module has its input end connected to the output end of the optical transceiver module of the near-end unit; The signal processing module has its input end connected to the output end of the optical module; The power amplifier module has its input terminal connected to the output terminal of the signal processing module, and its output terminal connected to the input terminal of the first signal transceiver module.

5. The repeater of claim 1, wherein The power regulation module includes: The power acquisition unit is used to acquire the power information of the digital signal after it has been down-converted by the down-conversion module; A power comparison unit is used to compare the power information of the digital signal with a preset power range to obtain a comparison result; A power adjustment unit is used to adjust the power of the digital signal based on the comparison result.

6. The repeater of claim 5, wherein, The power regulation unit includes: Controller; A power amplifier, connected to the controller, is used to amplify the power of the digital signal when the comparison result indicates that the power information is less than the minimum value of the preset power range. A power attenuator, connected to the controller, is used to attenuate the power of the digital signal when the comparison result indicates that the power information is greater than the maximum value of the preset power range.

7. The repeater of claim 1, wherein The repeater also comprises a satellite timing module for timing synchronization of the near-end machine and the far-end machine.

8. The repeater of claim 1, wherein, The housings of the near-end machine and the far-end machine are made of die-cast aluminum alloy, and the housings are internally provided with heat-conducting metal plates.

9. The repeater of claim 1, wherein, The frequency selection module comprises a surface acoustic wave filter or a cavity filter.

10. A communication system, characterized by A repeater comprising any one of the features of claims 1-9.

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