Passive frequency shift 5G MIMO indoor coverage system based on DAS

Abstract

The invention provides a DAS-based passive frequency shift 5G MIMO indoor coverage system, which comprises a frequency shift control device, a special combiner and a DAS-based tail end coverage device, and is characterized in that the frequency shift control device receives two paths of same carrier frequency MIMO signals sent by a 5G MIMO signal source; and one path of same-carrier-frequency MIMO signals is selected to be subjected to digital frequency shift processing and then enters a tail end coverage device through the special combiner, and passive frequency shift 5G MIMO indoor coverage is realized through frequency shift path signal recovery and delay tolerance compensation of the tail end coverage device. According to the invention, the digital filter and the DPD algorithm are optimized, and the other path is only designed in the tail end passive coverage device for delay compensation, so that a low-cost digital passive frequency shift indoor 5G MIMO depth coverage scheme is successfully realized.

Description

Technical Field

[0001] The present invention relates to the field of indoor communication technology, and in particular to a DAS-based passive frequency shift 5G MIMO indoor coverage system. Background Art

[0002] Due to the wide operating bandwidth of the carrier frequency, the 5G outdoor macro base station signal has almost no coverage for indoor mobile phone users. However, more than 80% of mobile high-speed data services are used by mobile phone users in indoor environments. Therefore, it is urgent to solve the problem of 5G MIMO indoor deep coverage.

[0003] Through the existing distributed antenna DAS (Distributed Antenna System), it is possible to quickly promote the implementation of 5G MIMO indoor deep coverage. There are two main technical solutions: passive frequency shift and active frequency shift. In the active frequency shift solution, it is necessary to introduce a DC power supply into the DAS system, mainly to carry out the DAS system redistribution process based on the directional coupler replacement operation. However, this method is difficult to construct and the cost is very high; in the passive frequency shift solution, it is only necessary to add a frequency shift control unit at the source end, replace the dedicated combiner, and replace the original indoor antenna with a passive frequency shift coverage device at the end, thus becoming the mainstream way to promote 5G MIMO indoor deep coverage based on the existing DAS system.

[0004] The existing DAS network is a single-channel system, while the 5G MIMO signal is two independent signals with the same carrier frequency. If they are directly injected into the DAS network, the two 5G MIMO signals with the same frequency will interfere with each other, which will make MIMO and even 5G basic data communication functions impossible to achieve. Moreover, in the existing 5G MIMO signal processing process, the size, weight, cost and energy consumption of the equipment are all high, and there is also a serious processing delay problem during digital processing. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a DAS-based passive frequency shift 5G MIMO indoor coverage system, which successfully realizes a low-cost digital passive frequency shift indoor 5G MIMO deep coverage solution by optimizing the digital filter and DPD algorithm, as well as another delay compensation design only in the terminal passive coverage device.

[0006] According to the purpose of the present invention, the passive frequency shift 5G MIMO indoor coverage system based on DAS proposed by the present invention includes: A frequency shift control device, a dedicated combiner, and a DAS-based terminal coverage device. The frequency shift control device receives two same-carrier frequency MIMO signals sent by a 5G MIMO signal source, selects one of the same-carrier frequency MIMO signals, processes it through digital frequency shifting, and then enters the terminal coverage device through the dedicated combiner. Passive frequency shift 5G MIMO indoor coverage is achieved through frequency shift path signal recovery and delay tolerance compensation of the terminal coverage device.

[0007] As a further improvement, the uplink port of the frequency shift control device is connected to a port of the 5G MIMO RRU, and the downlink port is connected to the DAS through the dedicated combiner, wherein the RF operating frequency of the uplink port is 2515-2675MHz, the working bandwidth is 160M, the downlink port operating frequency is 1395-1555MHz, the output power is 100W, and the processing delay is 500nS.

[0008] As a further improvement, the frequency shift control device performs digital frequency shift processing on one of the two MIMO signals with the same carrier frequency, and the frequency shift control device specifically includes: An uplink transceiver filter for receiving a 5G MIMO signal source, an uplink transceiver switch connected to the uplink transceiver filter, the two ends of the uplink transceiver switch being respectively connected to an uplink data processing module and a downlink data processing module, a low noise amplifier connected to the uplink data processing module, a frequency-shifted signal RF bandpass filter, a first power amplifier, a second power amplifier, and a directional coupler connected to the downlink data processing module, a downlink transceiver switch connected to the low noise amplifier and the directional coupler, and a downlink frequency filter, a local oscillator signal filter, and an accompanying local oscillator signal generator connected in sequence to the downlink transceiver switch.

[0009] As a further improvement, the uplink data processing module includes an uplink adjustable gain amplifier having one end connected to the uplink transceiver switch, and the other end of the uplink adjustable gain amplifier is connected to an uplink I / Q modulator and an uplink I / Q demodulator, wherein the uplink I / Q modulator and the uplink I / Q demodulator are connected respectively via a first uplink I / Q baseband analog filter and a second uplink I / Q baseband analog filter, and the uplink I / Q demodulator is connected to the low noise amplifier.

[0010] As a further improvement, the downlink data processing module includes a downlink adjustable gain amplifier connected to the uplink transceiver switch, and the downlink adjustable gain amplifier is connected to the frequency-shifted signal RF bandpass filter through a downlink I / Q demodulator, a digital pre-distortion processor and an analog I / Q modulator, respectively. A one-way channel is formed between the downlink I / Q demodulator and the digital pre-distortion processor, the first channel is connected through a first I / Q baseband signal analog-to-digital converter and a first I / Q baseband signal digital filter, the second channel is connected through a second I / Q baseband signal analog-to-digital converter and a second I / Q baseband signal digital filter, and three-way channels are formed between the digital pre-distortion processor and the analog I / Q modulator, the third channel is connected through the first baseband I / Q signal digital-to-analog converter and the first baseband I / Q signal analog low-pass filter, and the fourth channel is connected through the second baseband I / Q signal digital-to-analog converter and the second baseband I / Q signal analog low-pass filter.

[0011] As a further improvement, the frequency shift control device also includes a first local oscillator signal module and a second local oscillator signal module, wherein one end of the first local oscillator signal module is connected to the downlink I / Q demodulator, and the other end is connected to the uplink I / Q modulator, and one end of the second local oscillator signal module is connected to the analog I / Q modulator, and the other end is connected to the uplink I / Q demodulator.

[0012] As a further improvement, the end coverage device includes a signal multiplexer for separating the 5G frequency-shifted signal, one or more series-connected SAW filters, and a 5G MIMO signal frequency recovery circuit, wherein the one or more series-connected SAW filters are used for 5G MIMO direct-path signal delay tolerance compensation, and the 5G MIMO signal frequency recovery circuit is used to restore the 5G MIMO frequency-shifted signal to the original 5G MIMO frequency.

[0013] As a further improvement, the uplink transceiver filter is used to filter out spurious frequency signals other than the 5G MIMO carrier signal, and is specifically a cavity or dielectric filter that does not generate delay.

[0014] As a further improvement, the process of achieving passive frequency-shifting 5G MIMO indoor coverage through frequency-shifting path signal recovery and delay tolerance compensation of the terminal coverage device specifically includes the terminal coverage device restoring the 5G frequency-shifting path signal to the 5G MIMO signal frequency and sending it to one port of the orthogonal polarization antenna; and sending the 5G MIMO direct signal to the other port of the orthogonal polarization antenna after delay tolerance compensation of the SAW filter, thereby achieving passive frequency-shifting 5G MIMO indoor coverage.

[0015] As a further improvement, the dedicated combiner is used to combine the frequency-shifted path signals and accompanying local oscillator signals output by 2G signal sources, 3G signal sources, 4G signal sources, 5G signal sources, and 5G MIMO of the frequency shift control device into a terminal coverage device based on DAS.

[0016] The present invention proposes a method and system for intelligent interactive control of multimedia devices, which effectively improves the interactive capabilities of intelligent devices by setting intelligent interactions for different devices in multimedia application scenarios, and improves the user experience while meeting the intelligent requirements in intelligent application scenarios. The specific technical effects are as follows: (1) The passive frequency shifting system relies on the scalar DAS system. It only needs to add a set of frequency shifting control devices and a dedicated combiner, and replace the original indoor antenna with a coverage device at the end. The system utilizes existing assets and promotes 5G MIMO indoor deep coverage with fast speed, low cost and good effect.

[0017] (2) Frequency shift control device: For two 5G MIMO signals, only one is subjected to frequency shift processing. Digital modulation and demodulation, digital filtering and digital pre-distortion technology are introduced in the processing process to ensure that the 5G frequency shift signal retains the characteristics of the 5G MIMO signal and keeps key indicators such as EVM ACLR from deteriorating. By reducing the number of digital filter sections, removing the peak elimination processing link in the digital pre-distortion, and performing delay tolerance compensation in the terminal coverage device, the situation where the two 5G MIMO signals must be subjected to the same digital processing to ensure that the delay tolerance of the two 5G MIMO signals meets the requirements is broken, and the equipment size, weight, energy consumption and cost are reduced.

[0018] (3) The coverage device is a purely passive device that relies on the 5G frequency-shifted signal and the associated local oscillator signal to restore the 5G MIMO and adds SAW to compensate for delay tolerance. It is low-cost, light-weight, and suitable for large-scale deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a framework diagram of the DAS-based passive frequency shift 5G MIMO indoor coverage system proposed by the present invention; Figure 2 This is a physical picture of the frequency shift control device in the DAS-based passive frequency shift 5G MIMO indoor coverage system proposed in the present invention.

[0020] Figure 3 This is a framework diagram of the frequency shift control device in the DAS-based passive frequency shift 5G MIMO indoor coverage system proposed in the present invention.

[0021] Figure 4 This is a framework diagram of the terminal coverage device in the DAS-based passive frequency shift 5G MIMO indoor coverage system proposed in the present invention.

[0022] Figure 5 Schematic diagram of the terminal coverage device in the DAS-based passive frequency shift 5G MIMO indoor coverage system proposed in the present invention. DETAILED DESCRIPTION

[0024] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0025] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0026] Figure 1 The passive frequency shift 5G MIMO indoor coverage system based on DAS proposed by the present invention is as follows: Figure 1 As shown, the passive frequency shift 5G MIMO indoor coverage system of this embodiment includes a frequency shift control device, a dedicated combiner, and a terminal coverage device based on DAS. The frequency shift control device receives two MIMO signals with the same carrier frequency sent by the 5G MIMO signal source, selects one of the MIMO signals with the same carrier frequency after digital frequency shift processing, and enters the terminal coverage device through the dedicated combiner. The passive frequency shift 5G MIMO indoor coverage is achieved through the frequency shift path signal recovery and delay tolerance compensation of the terminal coverage device. In this embodiment, the dedicated combiner combines the 2G, 3G, 4G, 5G and 5G MIMO frequency shift path signals and accompanying local oscillator signals of the frequency shift control device into the DAS system.

[0027] Figure 2 This is a physical picture of the frequency shift control device in the DAS-based passive frequency shift 5G MIMO indoor coverage system proposed by the present invention, as shown in Figure 2As shown, the uplink port of the frequency shift control device is connected to a port of the 5G MIMO RRU (Remote Radio Unit), and the downlink port is connected to the DAS through the dedicated combiner, wherein the uplink port RF operating frequency is 2515-2675MHz, the working bandwidth is 160M, the downlink port operating frequency is 1395-1555MHz, the output power is 100W, and the processing delay is 500nS. The CW (continuous wave) frequency of the local oscillator output along the path is 1120MHz and the power is 200W.

[0028] In this embodiment, the frequency shift control device performs digital frequency shift processing on one of the two MIMO signals with the same carrier frequency. Specifically, one of the two MIMO signals of the 5G MIMO signal source is frequency shifted to a frequency suitable for DAS transmission and without interference to mobile communication, i.e., the 5G MIMO frequency shift path signal. At the same time, a local oscillator CW wave signal is output, and the terminal coverage device restores the 5G MIMO frequency shift path signal to the 5G MIMO signal frequency. Figure 3 As shown, the frequency shift control device specifically includes: An uplink transceiver filter 4 for receiving a 5G MIMO signal source, an uplink transceiver switch 5 connected to the uplink transceiver filter, the two ends of the uplink transceiver switch 5 being respectively connected to an uplink data processing module A and a downlink data processing module B, a low noise amplifier 31 connected to the uplink data processing module A, a frequency-shifted signal RF bandpass filter 18, a first power amplifier 19, a second power amplifier 20, and a directional coupler 21 connected to the downlink data processing module B, a downlink transceiver switch 24 connected to the low noise amplifier 31 and the directional coupler 21, and a downlink frequency filter 25, a local oscillator signal filter 33 and an accompanying local oscillator signal generator 32 connected in sequence to the downlink transceiver switch 24.

[0029] In this embodiment, the uplink transceiver filter 4 is used to filter out spurious frequency signals other than the 5G MIMO carrier signal. It must be a cavity or dielectric filter that does not generate delay, and a SAW (surface acoustic wave) filter with a large delay must not be used. The uplink transceiver switch 5 is used to separate / combine 5G MIMO transceiver signals. The frequency-shifted signal RF bandpass filter 18 cannot use SAW or other large-delay filters. The first power amplifier 19 is a frequency-shifted signal gain amplifier, and the second power amplifier 20 is a linear power amplifier, which is used to provide 5G frequency-shifted signal power to the DAS.

[0030] The uplink data processing module A includes an uplink adjustable gain amplifier 26 whose one end is connected to the uplink port transceiver switch, and the other end of the uplink adjustable gain amplifier is connected to an uplink I / Q (In-phase Quadrature) modulator 27 and an uplink I / Q demodulator 30, wherein the uplink I / Q modulator 27 and the uplink I / Q demodulator 30 are connected respectively through a first uplink I / Q baseband analog filter 28 and a second uplink I / Q baseband analog filter 29, and the uplink I / Q demodulator 30 is connected to the low noise amplifier 31.

[0031] The downlink data processing module B includes a downlink adjustable gain amplifier 6 connected to the uplink transceiver switch, and the downlink adjustable gain amplifier is connected to the bandpass filter 18 through a downlink I / Q demodulator 7, a digital pre-distortion processor 12 and an analog I / Q modulator 17, respectively. A two-way channel is formed between the downlink I / Q demodulator 7 and the digital pre-distortion processor 12, the first channel is connected to the first I / Q baseband signal analog-to-digital converter 8 and the first I / Q baseband signal digital filter 10, the second channel is connected to the second I / Q baseband signal analog-to-digital converter 9 and the second I / Q baseband signal digital filter 11, and three or four channels are formed between the digital pre-distortion processor 12 and the analog I / Q modulator 17, the third channel is connected to the first baseband I / Q signal digital-to-analog converter 13 and the first baseband I / Q signal analog low-pass filter 15, and the fourth channel is connected to the second baseband I / Q signal digital-to-analog converter 14 and the second baseband I / Q signal analog low-pass filter 16.

[0032] In this embodiment, the downlink adjustable gain amplifier 6 is used to make the frequency shift control device adaptive to different levels of 5G MIMO signal source output power. The first baseband signal digital filter 10 and the second I / Q baseband signal digital filter 11 are used for frequency shift control to generate the shaping filter of the frequency shift 5G MIMO signal, which is an important link in the differential processing delay of the frequency shift control device. The digital predistortion processor 12 is the core device of the frequency shift control device, and its function is to improve EVM ACLR and power amplifier efficiency. Digital predistortion technology is to predistort the 5GOFDM (Orthogonal Frequency Division Multiplexing) modulated signal input to the power amplifier in advance. Such a predistorted signal is opposite to the nonlinear distortion of the power amplifier itself, so the nonlinear power amplifier can be corrected into a linear power amplifier to ensure that the indicators such as EVM ACLR of the power amplifier output 5G OFDM modulated signal are not deteriorated. However, there is a requirement for the DPD linear correction power amplifier: the peak power of the input signal cannot exceed the input 1dB compression point of the power amplifier tube.

[0033] The peak-to-average ratio of the original signal modulated by 5G NR OFDM is relatively high. If the amplitude of the original signal of 5G OFDM does not exceed the 1dB compression point power of the power amplifier tube, a power amplifier tube device with a large output power must be selected. Not only is the device cost expensive, but the efficiency is also low and the energy consumption is also high. Although the original signal of 5G NR (new wireless) OFDM modulation has a high peak-to-average ratio, the probability of the peak occurring is low and the duration is short. If appropriate peak elimination measures are taken to eliminate the peak of the original signal, the impact on the quality of the 5G OFDM signal can be ignored. Therefore, the linearization of the power amplifier of 5G NR RRU adopts the joint algorithm of CFR (Crest Factor Reduction) + DPD (Digital Pre-Distortion). The input source of the frequency shift controller is 5GNRRRU, and its output 5G NR signal has been processed by peak elimination. Therefore, the frequency shift controller does not need the joint algorithm of CFR+DPD for power amplifier linearization, but only needs the DPD algorithm alone.

[0034] By eliminating the DPD optimization algorithm of the peak elimination link, the processing delay is ≤515nS, so it is also an important link to generate processing delay. The first baseband I / Q signal digital-to-analog converter 13 and the second baseband I / Q signal digital-to-analog converter 14 are used to convert the I / Q baseband digital signal into a baseband analog signal. The analog I / Q modulator 17 is used to move the 5G MIMO signal frequency to a frequency suitable for DAS system transmission without interfering with the mobile communication frequency.

[0035] The frequency shift control device also includes a first local oscillator signal module 22 and a second local oscillator signal module 23, wherein one end of the first local oscillator signal module 22 is connected to the downlink I / Q demodulator 7, and the other end is connected to the uplink I / Q modulator 27 and provides a local oscillator source, and one end of the second local oscillator signal module 23 is connected to the analog I / Q modulator 17, and the other end is connected to the uplink I / Q demodulator 30 and provides a local oscillator source.

[0036] In this embodiment, the end coverage device is used to restore the 5G frequency shift path signal to the 5G MIMO signal frequency and send it to one port of the orthogonal polarization antenna. The 5G MIMO direct signal is sent to the other port of the orthogonal polarization antenna after the SAW filter delay tolerance compensation. Figure 4 and 5As shown, the end coverage device includes a signal multiplexer 34 for separating 5G frequency-shifted signals, one or more SAW filters 35 connected in series, and a 5G MIMO signal frequency recovery circuit 36, wherein one or more SAW filters connected in series are used for 5G MIMO direct-path signal delay tolerance compensation, and the 5G MIMO signal frequency recovery circuit is used to restore the 5G MIMO frequency-shifted signal to the original 5G MIMO frequency. In this embodiment, the SAW filter model is: the filter QGSA2G59EBSP1 of Zhouxun Technology, the operating frequency B41_TRX 2515~2675MHz (160MHz) SAW1411 package, and the core of the 5G MIMO signal frequency recovery circuit 36 ​​is a high-power high-linearity passive mixer, which can use the YC511 mixer of Yingchen Company.

[0037] The uplink transceiver filter is used to filter out spurious frequency signals other than the 5G MIMO carrier signal, and is specifically a cavity or dielectric filter that does not generate delay.

[0038] The process of realizing passive frequency-shifting 5G MIMO indoor coverage through frequency-shifting path signal recovery and delay tolerance compensation of the terminal coverage device specifically includes the terminal coverage device restoring the 5G frequency-shifting path signal to the 5G MIMO signal frequency and sending it to one port of the orthogonal polarization antenna 37; and sending the 5G MIMO direct signal to the other port of the orthogonal polarization antenna 37 after delay tolerance compensation of the SAW filter, thereby realizing passive frequency-shifting 5G MIMO indoor coverage.

[0039] The present invention proposes a passive frequency shift 5G MIMO indoor coverage system based on DAS. To achieve 5G MIMO indoor deep coverage, the two orthogonal polarization antenna ends of the terminal coverage device must input two 5G MIMO signals with the same carrier frequency. However, the existing DAS is a single-channel system and is not suitable for transmitting two MIMO signals with the same carrier frequency. Therefore, the frequency shift control device must shift one of the 5G MIMO signals to a frequency that does not interfere with the mobile communication frequency and is suitable for DAS transmission, and then restore the 5G MIMO signal carrier frequency in the terminal coverage device. Since 5GMIMO has strict requirements on amplitude and EVM ACLR, digital frequency shift technology must be used. Digital frequency shift technology is very significant in improving the technical indicators of the frequency shift control device. If the two MIMO signals are processed in the same way, the equipment volume, weight, power consumption and cost are very high. If only one channel is processed, it is necessary to try to compensate for the delay difference between the two channels. The present invention adopts a method of shortening the number of transmission filter sections, canceling the peak elimination processing, and performing delay compensation in the terminal coverage unit to successfully achieve single-channel frequency conversion processing to support 5G MIMO indoor deep coverage function.

[0040] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. DAS-based passive frequency shift 5G MIMO indoor coverage system, characterized by: The system comprises: A frequency shift control device, a dedicated combiner, and a DAS-based terminal coverage device. The frequency shift control device receives two same-carrier frequency MIMO signals sent by a 5G MIMO signal source, selects one of the same-carrier frequency MIMO signals, processes it through digital frequency shifting, and then enters the terminal coverage device through the dedicated combiner. Passive frequency shift 5G MIMO indoor coverage is achieved through frequency shift path signal recovery and delay tolerance compensation of the terminal coverage device.

2. The DAS-based passive frequency shift 5G MIMO indoor coverage system according to claim 1, characterized in that: The uplink port of the frequency shift control device is connected to a port of the 5G MIMO RRU, and the downlink port is connected to the DAS through the dedicated combiner, wherein the RF operating frequency of the uplink port is 2515-2675MHz, the working bandwidth is 160M, the downlink port operating frequency is 1395-1555MHz, the output power is 100W, and the processing delay is 500nS.

3. The DAS-based passive frequency shift 5G MIMO indoor coverage system according to claim 2, characterized in that: The frequency shift control device performs digital frequency shift processing on one of the two MIMO signals with the same carrier frequency, and the frequency shift control device specifically includes: An uplink transceiver filter for receiving a 5G MIMO signal source, an uplink transceiver switch connected to the uplink transceiver filter, the two ends of the uplink transceiver switch being respectively connected to an uplink data processing module and a downlink data processing module, a low noise amplifier connected to the uplink data processing module, a frequency-shifted signal RF bandpass filter, a first power amplifier, a second power amplifier, and a directional coupler connected to the downlink data processing module, a downlink transceiver switch connected to the low noise amplifier and the directional coupler, and a downlink frequency filter, a local oscillator signal filter, and an accompanying local oscillator signal generator connected in sequence to the downlink transceiver switch.

4. The DAS-based passive frequency shift 5G MIMO indoor coverage system according to claim 3, characterized in that: The uplink data processing module includes an uplink adjustable gain amplifier connected to the uplink port transceiver switch at one end, and the other end of the uplink adjustable gain amplifier is connected to an uplink I / Q modulator and an uplink I / Q demodulator, wherein the uplink I / Q modulator and the uplink I / Q demodulator are connected respectively via a first uplink I / Q baseband analog filter and a second uplink I / Q baseband analog filter, and the uplink I / Q demodulator is connected to the low noise amplifier.

5. The DAS-based passive frequency shift 5G MIMO indoor coverage system according to claim 3, characterized in that: The downlink data processing module includes a downlink adjustable gain amplifier connected to the uplink transceiver switch, and the downlink adjustable gain amplifier is connected to the frequency-shifted signal radio frequency bandpass filter through a downlink I / Q demodulator, a digital predistortion processor, and an analog I / Q modulator, respectively. A one-way channel is formed between the downlink I / Q demodulator and the digital predistortion processor, the first channel is connected through a first I / Q baseband signal analog-to-digital converter and a first I / Q baseband signal digital filter, the second channel is connected through a second I / Q baseband signal analog-to-digital converter and a second I / Q baseband signal digital filter, and three-way channels are formed between the digital predistortion processor and the analog I / Q modulator, the third channel is connected through a first baseband I / Q signal digital-to-analog converter and a first baseband I / Q signal analog low-pass filter, and the fourth channel is connected through a second baseband I / Q signal digital-to-analog converter and a second baseband I / Q signal analog low-pass filter.

6. The DAS-based passive frequency shift 5G MIMO indoor coverage system according to claim 4 or 5, characterized in that: The frequency shift control device also includes a first local oscillator signal module and a second local oscillator signal module, wherein one end of the first local oscillator signal module is connected to the downlink I / Q demodulator, and the other end is connected to the uplink I / Q modulator, and one end of the second local oscillator signal module is connected to the analog I / Q modulator, and the other end is connected to the uplink I / Q demodulator.

7. The DAS-based passive frequency shift 5G MIMO indoor coverage system according to claim 1, characterized in that: The end coverage device includes a signal multiplexer for separating 5G frequency-shifted signals, one or more series-connected SAW filters, and a 5G MIMO signal frequency recovery circuit, wherein the one or more series-connected SAW filters are used for 5G MIMO direct-path signal delay tolerance compensation, and the 5G MIMO signal frequency recovery circuit is used to restore the 5G MIMO frequency-shifted signal to the original 5G MIMO frequency.

8. The DAS-based passive frequency shift 5G MIMO indoor coverage system according to claim 7, characterized in that: The uplink transceiver filter is used to filter out spurious frequency signals other than the 5G MIMO carrier signal, and is specifically a cavity or dielectric filter that does not generate delay.

9. The DAS-based passive frequency shift 5G MIMO indoor coverage system according to claim 8, characterized in that: The process of realizing passive frequency-shifting 5G MIMO indoor coverage through frequency-shifting path signal recovery and delay tolerance compensation of the terminal coverage device specifically includes the terminal coverage device restoring the 5G frequency-shifting path signal to the 5G MIMO signal frequency and sending it to one port of the orthogonal polarization antenna; and sending the 5G MIMO direct signal to the other port of the orthogonal polarization antenna after delay tolerance compensation of the SAW filter, thereby realizing passive frequency-shifting 5G MIMO indoor coverage.

10. The DAS-based passive frequency shift 5G MIMO indoor coverage system according to claim 8, characterized in that: The dedicated combiner is used to combine the frequency-shifted path signals and the accompanying local oscillator signals output by the 2G signal source, 3G signal source, 4G signal source, 5G signal source, and 5G MIMO of the frequency shift control device into a terminal coverage device based on DAS.

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