A room division coverage system and method based on frequency shift MIMO technology

Abstract

The application relates to a room division covering system and method based on frequency shift MIMO technology, which comprises a signal source access layer, a frequency shift MIMO core processing layer and a distributed covering layer. The signal source access layer is used for acquiring multi-system signal sources; the frequency shift MIMO core processing layer is connected with the signal source access layer and the distributed covering layer respectively, is used for receiving the multi-system signal sources and the real-time feedback of channel parameters of indoor areas of the distributed covering layer, performing cooperative detection of channels and scenes, combining frequency shift MIMO technology to perform cooperative processing, and obtaining frequency shift-MIMO cooperative signals; and the distributed covering layer is used for receiving the frequency shift-MIMO cooperative signals, forming a radio frequency covering field based on frequency shift MIMO technology, accessing adaptive terminals, and collecting real-time channel parameters of indoor areas. Compared with the prior art, the application has the advantages of high covering rate and adaptive environmental change.

Description

Technical Field

[0001] This invention relates to the field of wireless communication, and in particular to an indoor distributed coverage system and method based on frequency-shifting MIMO technology. Background Technology

[0002] MIMO (Multiple-Input Multiple-Output) technology is a spatially-based method for improving system capacity. It employs parallel transmission and reception by multiple antennas, using spatial multiplexing and diversity to increase system capacity without increasing bandwidth. However, indoor wireless signal coverage involves transmitting the base station signal to each floor via wired connections, which is then radiated outwards by antennas distributed at various points. This presents a bottleneck for MIMO technology in wired systems, preventing the high-speed advantages of 5G networks from being realized in indoor distributed antenna systems (DAS). Therefore, from 4G LTE to 5G NR deployment, solving the indoor coverage problem of MIMO signals has become a thorny issue for the three major telecom operators.

[0003] The frequency-shifting MIMO scheme shifts one or more frequencies in a 5G MIMO channel, combines the signals, and transmits them using the feeder of an existing single-channel indoor distribution system. The remote unit, after modification, receives the combined signal and then re-shifts it back to the signal of the corresponding source channel. This allows for the transmission of two signals within a single physical transmission path using frequency division multiplexing. This technology maximizes the use of existing indoor distribution systems built during the 2G and 3G eras. MIMO upgrades for 4G and 5G can be completed simply by replacing RRUs and remote antennas, significantly reducing construction costs and shortening the construction cycle. Testing and analysis have shown improvements in coverage and speed compared to before the upgrade.

[0004] However, traditional solutions suffer from insufficient integration of frequency shifting and MIMO technologies. Specifically, frequency shifting systems simply move the signal to a specific frequency for transmission, then restore it to the original frequency at the destination. In this process, the frequency shifting parameters are often static, failing to dynamically adjust the shift frequency based on real-time channel quality (such as signal-to-noise ratio and transmission distance) in different indoor areas. This results in coverage blind spots or extremely poor user experience in areas with poor signal quality. Furthermore, indoor channels are time-varying and spatially uneven. For example, signal quality is good near windows (line-of-sight transmission), while signal quality is poor in the core area of ​​a building or at corners (non-line-of-sight transmission). Existing indoor distribution systems typically use a "one-size-fits-all" transmission mode, unable to intelligently switch MIMO stream types (multiplexed stream, diversity stream, or hybrid stream) based on channel conditions in different areas. Using spatial multiplexing in areas with poor channel quality leads to a sharp increase in bit error rate, compromising service reliability; while using only diversity stream in areas with good channel quality wastes spectrum resources. In addition, existing systems are unable to achieve coordinated scheduling across multiple regions and cannot provide differentiated quality of service guarantees for high-priority scenarios (such as emergency communications and critical IoT nodes).

[0005] In summary, existing indoor distribution systems generally suffer from problems such as low spectrum efficiency, rigid multi-area scheduling, poor compatibility with multiple standards, and insufficient support for MIMO technology, which cannot meet the future demand for high-capacity, high-reliability, and low-latency indoor coverage. Summary of the Invention

[0006] The purpose of this invention is to provide an indoor distributed coverage system and method based on frequency-shifting MIMO technology that achieves joint optimization of coverage and capacity.

[0007] The objective of this invention can be achieved through the following technical solutions: An indoor distributed coverage system based on frequency-shifting MIMO technology includes a source access layer, a frequency-shifting MIMO core processing layer, and a distributed coverage layer. The source access layer is used to acquire multi-standard source signals. The frequency-shift MIMO core processing layer is connected to the source access layer and the distributed coverage layer respectively. It is used to receive the multi-standard source signals and the channel parameters of each indoor area fed back in real time by the distributed coverage layer, perform channel-scene cooperative detection, and perform cooperative processing in combination with frequency-shift MIMO technology to obtain frequency-shift MIMO cooperative signals. The distributed coverage layer is used to receive the frequency-shift MIMO cooperative signal and form a radio frequency coverage field based on frequency-shift MIMO technology to access the adapted terminal and to collect channel parameters of various indoor areas in real time.

[0008] Furthermore, the source access layer includes a multimode source combiner and a low-latency synchronization module. The multimode source combiner is used to acquire the multi-standard source signals. The low-latency synchronization module is used to generate a unified time reference using GPS and BeiDou dual-mode synchronization technology, and to synchronize multi-standard signal sources using the unified time reference. Synchronization processing is performed to obtain multi-standard source signals with embedded synchronization representations. .

[0009] Furthermore, the frequency-shift MIMO core processing layer includes a data receiving module, a preprocessing module, a clustering and partitioning module, a linkage scheduling module, a collaborative processing module, and an anomaly detection and processing module. The data receiving module is used to receive multi-standard source signals output by the source access layer. Channel parameters fed back in real time by the distributed overlay layer , i =1,2,...,N represents the number of valid sampling points, corresponding to different areas indoors. The channel signal-to-noise ratio (SNR) For signal transmission distance, Indicates scene priority; Preprocessing module: used for processing the multi-standard source signals. Filtering is performed to remove Gaussian white noise introduced during transmission, resulting in a preprocessed source signal. and the channel parameters Normalization and fusion processing are performed to obtain the comprehensive evaluation index of the sampling points. ; Clustering module: used to comprehensively evaluate indicators based on the sampling points. The K-means clustering algorithm was used to divide the N sampling points into three categories of channel regions. ,in Indicates a high-quality channel area. Indicates the medium channel region. Indicates a poor-quality channel area; Coordinated scheduling module: for the three types of channel area division results Based on the path loss formula, the optimal frequency shift point for each type of channel region is calculated to minimize signal transmission loss. , forming frequency scheduling instructions Simultaneously, based on the channel area type and scenario type, the MIMO stream type and antenna configuration are scheduled, and the precoding matrix is ​​calculated. , forming MIMO scheduling instructions ,in , , These represent the optimal frequency shift points for the high-quality channel region, the medium-quality channel region, and the low-quality channel region, respectively. Represented as: , , In the formula, For signal transmission path loss, For the signal transmission distance of each type of channel area, This serves as the baseline value for path loss. , These represent the signal transmission distance and the loss coefficient corresponding to the frequency point, respectively. For frequency point constraints, range Frequency constraints corresponding to high-quality channel regions, range Frequency constraints corresponding to the medium channel region, range Frequency constraints corresponding to poor-quality channel regions; Cooperative processing module: used for scheduling instructions based on the frequency points. MIMO scheduling instructions Preprocessed source signal Frequency shifting and MIMO stream co-processing is performed to obtain the frequency shifting-MIMO co-processing signal; Anomaly detection and handling module: Used to detect in real time whether there is an anomaly in the frequency shift-MIMO cooperative signal. If so, it returns to the linkage scheduling module and immediately triggers rescheduling. If not, there is no need to return, and the frequency shift-MIMO cooperative signal is distributed to each channel area in the room.

[0010] Furthermore, in the clustering partitioning module, the objective function of the K-means clustering algorithm is: , In the formula, To minimize the sum of squared errors within the class, For the first k The set of sampling points corresponds to different types of channel regions. For the first k Comprehensive evaluation index of sampling points The mean.

[0011] Furthermore, in the preprocessing module, a comprehensive evaluation index for the sampling points is obtained. The execution steps include: Regarding the channel signal-to-noise ratio and signal transmission distance Normalization is performed, where the normalization operation expression is: , , In the formula, The normalized channel signal-to-noise ratio, The minimum channel signal-to-noise ratio among all sampling points. The maximum channel signal-to-noise ratio among all sampling points. For normalized signal transmission distance, The minimum signal transmission distance among all sampling points. The maximum signal transmission distance among all sampling points; For the above Perform scene priority quantization to obtain priority quantization values. , where 0.5 represents the quantization value for normal priority scenarios and 1 represents the quantization value for high priority scenarios; The normalized channel signal-to-noise ratio Normalized signal transmission distance and priority quantization value Weighted fusion is performed to obtain the comprehensive evaluation index of the sampling points. , is represented as: , In the formula, , , These are the weighting coefficients.

[0012] Furthermore, in the linkage scheduling module, the MIMO scheduling instruction During execution, the scheduling rules followed are as follows: In the high-quality channel area and high-priority scenario, a 4×4 matrix MIMO multiplexing stream is adopted, where the 4×4 matrix represents that the antenna configuration includes 4 transmit antennas and 4 receive antennas. In the high-quality channel area and normal priority scenario, a 2×2 matrix MIMO multiplexing stream is adopted, where the 2×2 matrix represents that the antenna configuration includes 2 transmit antennas and 2 receive antennas. In the medium channel region and high priority scenario, a 2×2 matrix MIMO hybrid stream is used; In the medium channel region and normal priority scenario, a 2×2 matrix MIMO diversity stream is used; In the poor channel region, a 2×2 matrix MIMO diversity stream is used; Wherein, the precoding matrix It is based on the current channel matrix The calculated current channel matrix The dimension is determined by the antenna configuration, then the precoding matrix The calculation expression is: , In the formula, MIMO channel matrix The conjugate transpose of the matrix. The variance is Gaussian white noise. It is an identity matrix.

[0013] Furthermore, the collaborative processing module includes a frequency shift collaborative conversion unit, a MIMO stream collaborative processing unit, and a signal synthesis unit connected in sequence. Frequency shifting cooperative conversion unit: used for scheduling instructions based on the frequency points. For the preprocessed source signal Perform frequency shift conversion to convert it to the optimal frequency shift point for the corresponding channel type. The signal, where the conversion formula is: , In the formula, The optimal frequency shift point The signal, as a frequency-shifted radio frequency signal, The phase offset is derived from the preprocessed source signal. Internal embedded synchronization indicates calibration; MIMO Stream Co-processing Unit: Used for processing based on the MIMO scheduling instructions For the frequency-shifted radio frequency signal Perform MIMO stream mapping and precoding to generate a MIMO multi-stream signal, represented as: , In the formula, It is a MIMO multi-stream signal; Signal synthesis unit: synthesizes the MIMO multi-stream signal Signal synthesis was performed to obtain the frequency-shift-MIMO coordinated signal. , is represented as: , In the formula, It is a frequency-shift MIMO coordinated signal. , , These are frequency-shift-MIMO coordinated signals for three different channel regions. This refers to the number of MIMO transmit antennas. The first in the MIMO multi-stream signal road signal, This is the amplitude normalization coefficient.

[0014] Furthermore, the distributed overlay layer includes a near-end unit, a remote unit, and a channel parameter acquisition module. The near-end unit is used to receive frequency-shift-MIMO cooperative signals from different channel regions. First, down-conversion and digitization processing are performed to obtain a digital signal, then electro-optical conversion processing is performed to convert it into an optical signal, and the optical signal is distributed. Remote unit: Deployed in various channel zones indoors, used to receive optical signals from corresponding channel zones, first convert the optical signals back into electrical signals, then perform clock data recovery and analog-to-digital conversion, up-conversion and channel filtering on the electrical signals in sequence, and finally amplify and transmit them into the air to form a radio frequency coverage field; Channel parameter acquisition module: used to collect channel parameters of various indoor areas in real time and send them to the frequency-shift MIMO core processing layer.

[0015] Furthermore, a power amplifier is used to amplify the electrical signal.

[0016] The present invention also provides an indoor coverage method for an indoor coverage system based on frequency-shifting MIMO technology as described above, comprising the following steps: S1. Acquire multi-standard signal sources using the source access layer; S2. The frequency-shifting MIMO core processing layer receives multi-standard source signals collected by the source access layer and channel parameters of various indoor areas fed back in real time by the distributed coverage layer, performs channel-scene collaborative detection, and performs collaborative processing in combination with frequency-shifting MIMO technology to obtain frequency-shifting MIMO collaborative signals. S3. The distributed coverage layer receives the frequency-shift MIMO cooperative signal and forms a radio frequency coverage field based on frequency-shift MIMO technology to access the adapted terminal, and collects the channel parameters of each area in the room in real time and feeds them back to the frequency-shift MIMO core processing layer. Steps S2-S3 are repeated to form a real-time dynamic radio frequency coverage field.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention combines the channel parameters of each area in the room, so that the frequency shift MIMO core processing layer can sense the channel changes in real time and perform channel-scene collaborative detection, thereby dynamically adjusting the processing strategy so that the system always matches the current channel conditions and improves the reliability and stability of coverage. At the same time, this invention combines frequency shift technology with MIMO technology, and improves spectrum efficiency and system capacity through deep collaborative processing, thereby achieving joint optimization of coverage and capacity.

[0018] (3) Traditional indoor distribution systems treat the indoor environment as a uniform environment. This invention calculates the comprehensive evaluation index of sampling points by fusing channel parameters and divides the sampling points using the K-means clustering algorithm, thereby realizing a refined understanding of the indoor environment. This allows the system to no longer blindly transmit signals but to automatically identify different channel areas. This partitioning effect lays the physical foundation for subsequent differentiated services and ensures the targeted coverage.

[0019] (4) Existing frequency shifting technology usually sets the frequency points statically, which cannot cope with environmental changes. This invention calculates the signal transmission path loss and calculates the frequency point with the minimum signal transmission loss in each channel area in real time. In the poor channel area, a lower frequency point is automatically selected. The physical characteristics of the strong penetration of low frequency are used to effectively extend the coverage distance and achieve "blind spot filling". In the high channel area, a higher frequency point is automatically selected. The advantage of the large bandwidth of high frequency is used to improve the capacity. Therefore, this invention realizes the dynamic adaptation of frequency resources with the channel environment and maximizes the spectrum efficiency while ensuring coverage.

[0020] (5) This invention combines channel area type and scene priority to intelligently schedule MIMO stream type, breaking the limitation of traditional fixed MIMO mode. In addition, by using a precoding matrix calculated based on the current channel matrix and noise, it can effectively suppress interference between multiple users, enabling "multi-stream" to run along its path in complex indoor environments, significantly improving signal quality.

[0021] (6) This invention introduces an anomaly detection and processing module, which can immediately trigger the linkage scheduling module to reschedule when an anomaly occurs in the frequency shift-MIMO cooperative signal. This real-time closed-loop feedback mechanism ensures that the system can quickly respond to sudden environmental changes, has self-optimization capabilities, and improves the robustness of the system. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the system structure of the present invention. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0024] This embodiment provides an indoor distributed coverage system based on frequency-shifting MIMO technology, such as... Figure 1 As shown, the system includes: a source access layer 1, a frequency-shifting MIMO core processing layer 2, and a distributed coverage layer 3, wherein the source access layer 1 is connected to the frequency-shifting MIMO core processing layer 2, and the frequency-shifting MIMO core processing layer 2 is also connected to the distributed coverage layer 3.

[0025] Source access layer 1: This layer serves as the core of the system signal input, responsible for receiving multi-mode signal sources and simultaneously achieving low-latency synchronization and optimization of the sources, providing stable input for subsequent frequency-shift MIMO processing and for the processing of the subsequent frequency-shift MIMO core processing layer 2. Specifically, this source access layer 1 includes a multi-mode source combiner 11 and a low-latency synchronization module 12.

[0026] Multi-mode source combiner 11: Used to acquire multi-standard source signals. In this embodiment, the source types support 5G SA / NSA source, 4G LTE source, and are compatible with 2G / 3G source. The source output power can be dynamically adjusted (10W~40W) to adapt to different indoor coverage scales.

[0027] Low-latency synchronization module 12: Used to generate a unified time reference for GPS and BeiDou dual-mode synchronization technology, and to use this unified time reference to synchronize signals from multiple signal sources. Synchronization processing is performed to obtain multi-standard source signals with embedded synchronization representations. This module adopts a hardware-level synchronization mechanism to avoid MIMO stream interference and delay superposition caused by asynchronous signal sources, and can solve the problem of signal source synchronization lag in traditional indoor distribution systems.

[0028] Frequency-shift MIMO core processing layer 2: This core layer of the system aims to achieve deep integration of frequency shifting and MIMO technologies, breaking through the limitations of the original two core technologies operating independently, and constructing an integrated linkage processing mechanism to realize full-process coordination of channel adaptation and resource allocation. Specifically, this frequency shifting MIMO core processing layer 2 includes a data receiving module 21, a preprocessing module 22, a clustering and partitioning module 23, a linkage scheduling module 24, a collaborative processing module 25, and an anomaly detection and processing module 26.

[0029] Data receiving module 21: Used to receive multi-standard source signals output from source access layer 1 The channel parameters are fed back in real time by the channel parameter acquisition module 33 in the distributed coverage layer 3. , i =1,2,...,N represents the number of valid sampling points, corresponding to different areas indoors. The channel signal-to-noise ratio (SNR) For signal transmission distance, This indicates the priority of the scene. For example, operating rooms and conference rooms are marked as high-priority scenes, while corridors and restrooms are marked as normal-priority scenes.

[0030] Preprocessing module 22: Used for processing multi-standard source signals Filtering is performed to remove Gaussian white noise introduced during transmission, resulting in a preprocessed source signal. To adjust channel parameters In and Normalization is performed to eliminate the influence of dimensions and facilitate subsequent clustering calculations. The normalization formula is as follows: , , In the formula, The normalized channel signal-to-noise ratio, The minimum channel signal-to-noise ratio among all sampling points. The maximum channel signal-to-noise ratio among all sampling points. For normalized signal transmission distance, The minimum signal transmission distance among all sampling points. The maximum signal transmission distance among all sampling points; for Scenario priority quantization is performed: high-priority scenarios are quantized to 1, and normal-priority scenarios are quantized to 0.5, resulting in priority quantization values. ( ); Then , , By performing fusion calculations, a comprehensive evaluation index for each sampling point is obtained. For subsequent clustering, the comprehensive evaluation index is used. The calculation expression is: , This comprehensive evaluation index The weighting is as follows: signal-to-noise ratio accounts for 60%, transmission distance accounts for 20%, and scenario priority accounts for 20%, prioritizing channel quality and latency requirements.

[0031] This module optimizes the received data, eliminating interference and the influence of units, and comprehensively evaluates the indicators. This provides a unified evaluation standard for the subsequent clustering module 23, ensuring that the clustering results meet the requirements of channel quality and scenario.

[0032] Clustering Module 23: This module is used to use the K-means clustering algorithm to divide N sampling points according to a comprehensive evaluation index. Divided into 3 types of channel areas (Corresponding to high-quality, medium-quality, and low-quality channel regions). The core of this K-means clustering algorithm is to minimize the sum of squared errors within each cluster (SSE), and the objective function formula is as follows: , In the formula, To minimize the sum of squared errors within the class, For the first k A set of sampling points of different types (k=1,2,3, corresponding to high-quality, medium-quality, and low-quality channel areas respectively). For the first k Comprehensive evaluation index of sampling points The mean of the clustering is [0,1]. The termination condition for this clustering is: the change in SSE is ≤0.001, or the number of iterations reaches the set number.

[0033] In this embodiment, the clustering result is based on the cluster mean. The mapping is divided into three types of channel regions, and combined with scene priority, a two-dimensional adaptation standard is formed: High-quality channel area (k=1): ,correspond This indicates that there is no obvious obstruction; Medium channel range (k=2): ,correspond This indicates slight obstruction; Poor channel region (k=3): ,correspond This indicates severe obstruction.

[0034] Linkage scheduling module 24: used to determine the channel area allocation results based on the three types of channels. To achieve frequency point and MIMO stream coordinated scheduling, the optimal frequency shift point for each type of channel region is calculated first by combining the path loss formula. , forming frequency scheduling instructions To ensure minimal signal transmission loss while controlling frequency shift delay, among which , , Let represent the optimal frequency shift points for the high-quality channel region, the medium-quality channel region, and the low-quality channel region, respectively. The path loss formula is: , The optimal frequency shift point The formula is: , In the formula, For signal transmission path loss, For the signal transmission distance of each type of channel area, This serves as a baseline value for path loss, suitable for indoor wireless transmission scenarios. , These represent the signal transmission distance and the loss coefficient corresponding to the frequency point, respectively. Indicates frequency constraints and high-quality channel area medium channel area Poor channel area .

[0035] Simultaneously, MIMO stream type and configuration scheduling is performed: based on the channel area type and scenario type, the MIMO stream type (multiplexed stream / diversity stream) and antenna configuration (2×2 / 4×4) are scheduled, while the precoding matrix is ​​calculated. , forming MIMO scheduling instructions The precoding matrix The design is based on the minimum mean square error criterion (MMSE), and its expression is: , In the formula, MIMO channel matrix The conjugate transpose of the matrix. The variance is Gaussian white noise. For identity matrix (dimension and match); MIMO scheduling instructions The scheduling rules to be executed are as follows: High-quality channel area + high priority: 4×4 MIMO multiplexed stream, It is a 4×4 matrix; Premium channel area + normal priority: 2×2 MIMO multiplexed stream. It is a 2×2 matrix; Medium channel area + high priority: 2×2 MIMO hybrid stream (multiplexing + diversity). It is a 2×2 matrix; Medium channel area + normal priority: 2×2 MIMO diversity stream It is a 2×2 matrix; Poor channel region: 2×2 MIMO diversity stream, It is a 2×2 matrix.

[0036] This skipping rule enables coordinated matching of "frequency points - stream resources - scenario requirements".

[0037] The above optimal frequency shift point Precoding matrix and path loss coefficient To form a set of scheduling parameters .

[0038] Cooperative processing module 25: This module is used to schedule commands based on frequency points. MIMO scheduling instructions Preprocessed source signal Frequency shifting and MIMO stream co-processing are performed to obtain a frequency shift-MIMO co-processing signal. Specifically, the co-processing module 25 includes a frequency shift co-processing unit, a MIMO stream co-processing unit, and a signal synthesis unit connected in sequence.

[0039] Frequency shifting coordination unit: used to receive frequency scheduling instructions. For the preprocessed source signal Perform frequency shift conversion to convert it to the optimal frequency shift point for the corresponding channel type. The frequency shift conversion formula for the signal is as follows: , In the formula, The optimal frequency shift point The signal, as a frequency-shifted radio frequency signal, The phase offset is derived from the preprocessed source signal. The internal embedded synchronization means calibration, which ensures the phase stability of the frequency shift signal. This means that even if the signal has undergone frequency shifting and MIMO processing, the signals of different standards and different channels still maintain strict phase synchronization. This ensures that the terminal does not need a complicated resynchronization process when switching or aggregating signals of different standards, thus achieving low-latency adaptation.

[0040] MIMO Stream Co-processing Unit: Used to receive MIMO scheduling instructions Based on the precoding matrix For the frequency-shifted signal MIMO stream mapping and precoding are performed to generate MIMO multi-stream signals. The processing formula is as follows: , In the formula, It is a MIMO multi-stream signal, and its dimension is... Matching: 4×4 MIMO corresponds to 4 signals, and 2×2 MIMO corresponds to 2 signals.

[0041] Signal synthesis unit: Used to synthesize MIMO multi-stream signals, ensuring uniform signal amplitude and avoiding inter-stream superposition distortion. The synthesis formula is as follows: , In the formula, It is a frequency-shift MIMO coordinated signal. , , These are frequency-shift-MIMO coordinated signals for three different channel regions. This refers to the number of MIMO transmit antennas. The first in the MIMO multi-stream signal road signal, This is the amplitude normalization coefficient.

[0042] Anomaly detection and processing module 26: Used to detect in real time whether there is an anomaly in the frequency shift-MIMO cooperative signal. If so, it returns to the linkage scheduling module 24 and immediately triggers rescheduling. If not, there is no need to return, and the frequency shift-MIMO cooperative signal is distributed to each channel area in the room. Distributed Coverage Layer 3: This layer is responsible for efficiently distributing the frequency-shift-MIMO coordinated signal to various indoor areas, achieving blind-spot-free coverage through distributed deployment. This distributed coverage layer 3 includes a near-end unit 31, a far-end unit 32, and a channel parameter acquisition module 33.

[0043] Near-end unit 31: Used to receive frequency-shift-MIMO cooperative signals in different channel regions. To improve the anti-interference capability of long-distance transmission, the near-end unit 31 receives... The signal is down-converted to a baseband signal and then digitized to obtain a digital signal. The digital signal is then converted into an optical signal for low-loss distribution through optical fiber.

[0044] Remote Unit 32: Multiple units are set up and deployed in various channel areas indoors. They are used to receive optical signals from the corresponding type of channel area after being distributed and transmitted. First, the optical signal is converted back into an electrical signal through photoelectric conversion. The signal may generate clock jitter after long-distance fiber optic transmission. The clock data recovery circuit will extract a clean clock source from the signal and use it to retime the data to eliminate jitter. If it is digital fiber optic transmission, digital-to-analog conversion is required to restore the digital stream to an analog baseband signal. Then, up-conversion and channel filtering are performed to obtain a clean, low-power radio frequency signal in a specific frequency band. Finally, it is amplified by a power amplifier and transmitted into the air to form a radio frequency coverage field without blind spots. This radio frequency coverage field is connected to the adapted terminal.

[0045] Channel parameter acquisition module 33: This module is used to acquire channel parameters of various indoor areas in real time and send them to the data receiving module 21 in the frequency shift MIMO core processing layer 2 for processing by the frequency shift MIMO core processing layer 2, so as to realize the closed-loop collaborative processing design of this system.

[0046] The specific steps for achieving indoor coverage using the aforementioned indoor distribution system include: S1. Acquire multi-standard source signals using source access layer 1; S2, the frequency-shift MIMO core processing layer 2 receives multi-standard source signals collected by the source access layer 1 and channel parameters of various indoor areas fed back in real time by the distributed coverage layer 3, performs channel-scene collaborative detection, and performs collaborative processing in combination with frequency-shift MIMO technology to obtain frequency-shift MIMO collaborative signals; S3. Distributed coverage layer 3 receives frequency-shift MIMO cooperative signals and forms a radio frequency coverage field based on frequency-shift MIMO technology to access compatible terminals, and collects channel parameters of various indoor areas in real time and feeds them back to frequency-shift MIMO core processing layer 2. Repeat steps S2-S3 to form a real-time dynamic radio frequency coverage field.

[0047] The rest is as described in the system above.

[0048] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0049] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An indoor distributed coverage system based on frequency-shifting MIMO technology, characterized in that, It includes the source access layer, the frequency-shifting MIMO core processing layer, and the distributed coverage layer. The source access layer is used to acquire multi-standard source signals. The frequency-shift MIMO core processing layer is connected to the source access layer and the distributed coverage layer respectively. It is used to receive the multi-standard source signals and the channel parameters of each indoor area fed back in real time by the distributed coverage layer, perform channel-scene cooperative detection, and perform cooperative processing in combination with frequency-shift MIMO technology to obtain frequency-shift MIMO cooperative signals. The distributed coverage layer is used to receive the frequency-shift MIMO cooperative signal and form a radio frequency coverage field based on frequency-shift MIMO technology to access the adapted terminal and to collect channel parameters of various indoor areas in real time.

2. The indoor distributed coverage system based on frequency-shifting MIMO technology according to claim 1, characterized in that, The source access layer includes a multimode source combiner and a low-latency synchronization module. The multimode source combiner is used to acquire the multi-standard source signals. The low-latency synchronization module is used to generate a unified time reference using GPS and BeiDou dual-mode synchronization technology, and to synchronize multi-standard signal sources using the unified time reference. Synchronization processing is performed to obtain multi-standard source signals with embedded synchronization representations. .

3. The indoor distributed coverage system based on frequency-shifting MIMO technology according to claim 1, characterized in that, The frequency-shift MIMO core processing layer includes a data receiving module, a preprocessing module, a clustering and partitioning module, a linkage scheduling module, a collaborative processing module, and an anomaly detection and processing module. The data receiving module is used to receive multi-standard source signals output by the source access layer. Channel parameters fed back in real time by the distributed overlay layer , i =1,2,...,N represents the number of valid sampling points, corresponding to different areas indoors. The channel signal-to-noise ratio (SNR) For signal transmission distance, Indicates scene priority; Preprocessing module: used for processing the multi-standard source signals. Filtering is performed to remove Gaussian white noise introduced during transmission, resulting in a preprocessed source signal. and the channel parameters Normalization and fusion processing are performed to obtain the comprehensive evaluation index of the sampling points. ; Clustering module: used to comprehensively evaluate indicators based on the sampling points. The K-means clustering algorithm was used to divide the N sampling points into three categories of channel regions. ,in Indicates a high-quality channel area. Indicates the medium channel region. Indicates a poor-quality channel area; Coordinated scheduling module: for the three types of channel area division results Based on the path loss formula, the optimal frequency shift point for each type of channel region is calculated to minimize signal transmission loss. , forming frequency scheduling instructions Simultaneously, based on the channel area type and scenario type, the MIMO stream type and antenna configuration are scheduled, and the precoding matrix is ​​calculated. , forming MIMO scheduling instructions ,in , , These represent the optimal frequency shift points for the high-quality channel region, the medium-quality channel region, and the low-quality channel region, respectively. Represented as: ， ， In the formula, For signal transmission path loss, For the signal transmission distance of each type of channel area, This serves as the baseline value for path loss. , These represent the signal transmission distance and the loss coefficient corresponding to the frequency point, respectively. For frequency point constraints, range Frequency constraints corresponding to high-quality channel regions, range Frequency constraints corresponding to the medium channel region, range Frequency constraints corresponding to poor-quality channel regions; Cooperative processing module: used for scheduling instructions based on the frequency points. MIMO scheduling instructions Preprocessed source signal Frequency shifting and MIMO stream co-processing is performed to obtain the frequency shifting-MIMO co-processing signal; Anomaly detection and handling module: Used to detect in real time whether there is an anomaly in the frequency shift-MIMO cooperative signal. If so, it returns to the linkage scheduling module and immediately triggers rescheduling. If not, there is no need to return, and the frequency shift-MIMO cooperative signal is distributed to each channel area in the room.

4. The indoor distributed coverage system based on frequency-shifting MIMO technology according to claim 3, characterized in that, In the clustering partitioning module, the objective function of the K-means clustering algorithm is: ， In the formula, To minimize the sum of squared errors within the class, For the first k The set of sampling points corresponds to different types of channel regions. For the first k Comprehensive evaluation index of sampling points The mean.

5. An indoor distributed coverage system based on frequency-shifting MIMO technology according to claim 3, characterized in that, In the preprocessing module, the comprehensive evaluation index of the sampling points is obtained. The execution steps include: Regarding the channel signal-to-noise ratio and signal transmission distance Normalization is performed, where the normalization operation expression is: ， ， In the formula, The normalized channel signal-to-noise ratio, The minimum channel signal-to-noise ratio among all sampling points. The maximum channel signal-to-noise ratio among all sampling points. For normalized signal transmission distance, The minimum signal transmission distance among all sampling points. The maximum signal transmission distance among all sampling points; For the above Perform scene priority quantization to obtain priority quantization values. , where 0.5 represents the quantization value for normal priority scenarios and 1 represents the quantization value for high priority scenarios; The normalized channel signal-to-noise ratio Normalized signal transmission distance and priority quantization value Weighted fusion is performed to obtain the comprehensive evaluation index of the sampling points. , is represented as: ， In the formula, , , These are the weighting coefficients.

6. An indoor distributed coverage system based on frequency-shifting MIMO technology according to claim 3, characterized in that, In the linkage scheduling module, the MIMO scheduling instruction During execution, the scheduling rules followed are as follows: In the high-quality channel area and high-priority scenario, a 4×4 matrix MIMO multiplexing stream is adopted, where the 4×4 matrix represents that the antenna configuration includes 4 transmit antennas and 4 receive antennas. In the high-quality channel area and normal priority scenario, a 2×2 matrix MIMO multiplexing stream is adopted, where the 2×2 matrix represents that the antenna configuration includes 2 transmit antennas and 2 receive antennas. In the medium channel region and high priority scenario, a 2×2 matrix MIMO hybrid stream is used; In the medium channel region and normal priority scenario, a 2×2 matrix MIMO diversity stream is used; In the poor channel region, a 2×2 matrix MIMO diversity stream is used; Wherein, the precoding matrix It is based on the current channel matrix The calculated current channel matrix The dimension is determined by the antenna configuration, then the precoding matrix The calculation expression is: ， In the formula, MIMO channel matrix The conjugate transpose of the matrix. The variance is Gaussian white noise. It is an identity matrix.

7. An indoor distributed coverage system based on frequency-shifting MIMO technology according to claim 3, characterized in that, The collaborative processing module includes a frequency shift collaborative conversion unit, a MIMO stream collaborative processing unit, and a signal synthesis unit connected in sequence. Frequency shifting cooperative conversion unit: used for scheduling instructions based on the frequency points. For the preprocessed source signal Perform frequency shift conversion to convert it to the optimal frequency shift point for the corresponding channel type. The signal, where the conversion formula is: ， In the formula, The optimal frequency shift point The signal, as a frequency-shifted radio frequency signal, The phase offset is derived from the preprocessed source signal. Internal embedded synchronization indicates calibration; MIMO Stream Co-processing Unit: Used for processing based on the MIMO scheduling instructions For the frequency-shifted radio frequency signal Perform MIMO stream mapping and precoding to generate a MIMO multi-stream signal, represented as: ， In the formula, It is a MIMO multi-stream signal; Signal synthesis unit: synthesizes the MIMO multi-stream signal Signal synthesis was performed to obtain the frequency-shift-MIMO coordinated signal. , is represented as: ， In the formula, It is a frequency-shift MIMO coordinated signal. , , These are frequency-shift-MIMO coordinated signals for three different channel regions. This refers to the number of MIMO transmit antennas. The first in the MIMO multi-stream signal road signal, This is the amplitude normalization coefficient.

8. An indoor distributed coverage system based on frequency-shifting MIMO technology according to claim 1, characterized in that, The distributed overlay layer includes a near-end unit, a remote unit, and a channel parameter acquisition module. The near-end unit is used to receive frequency-shift-MIMO cooperative signals from different channel regions. First, down-conversion and digitization processing are performed to obtain a digital signal, then electro-optical conversion processing is performed to convert it into an optical signal, and the optical signal is distributed. Remote unit: Deployed in various channel zones indoors, used to receive optical signals from corresponding channel zones, first convert the optical signals back into electrical signals, then perform clock data recovery and analog-to-digital conversion, up-conversion and channel filtering on the electrical signals in sequence, and finally amplify and transmit them into the air to form a radio frequency coverage field; Channel parameter acquisition module: used to collect channel parameters of various indoor areas in real time and send them to the frequency-shift MIMO core processing layer.

9. An indoor distributed coverage system based on frequency-shifting MIMO technology according to claim 8, characterized in that, The electrical signal is amplified using a power amplifier.

10. An indoor coverage method for an indoor coverage system based on frequency-shifting MIMO technology according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Acquire multi-standard signal sources using the source access layer; S2. The frequency-shifting MIMO core processing layer receives multi-standard source signals collected by the source access layer and channel parameters of various indoor areas fed back in real time by the distributed coverage layer, performs channel-scene collaborative detection, and performs collaborative processing in combination with frequency-shifting MIMO technology to obtain frequency-shifting MIMO collaborative signals. S3. The distributed coverage layer receives the frequency-shift MIMO cooperative signal and forms a radio frequency coverage field based on frequency-shift MIMO technology to access the adapted terminal, and collects the channel parameters of each area in the room in real time and feeds them back to the frequency-shift MIMO core processing layer. Steps S2-S3 are repeated to form a real-time dynamic radio frequency coverage field.

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