Train wireless signal enhancement system and method

Abstract

The invention relates to a train wireless signal enhancement system and method. The system comprises a central server, AP equipment, an intelligent metasurface array and a metasurface controller. Wherein the central server can receive base station signals, is connected with the Internet, and carries out communication data transmission with the AP equipment; the AP equipment establishes a wireless network coverage area in a train compartment by transmitting a wireless signal; the intelligent metasurface array is used for receiving and reflecting a wireless signal sent by the AP equipment; and the metasurface controller generates metasurface configuration parameters according to the uplink detection signal and the channel state report sent by the AP equipment, and dynamically adjusts the reflection state of the intelligent metasurface array based on the metasurface configuration parameters. According to the invention, the intelligent metasurface array and the corresponding controller are arranged in the carriage, so that the wireless signal in the carriage is enhanced by directional reflection, and the coverage range of the wireless signal in the carriage and the signal intensity in the carriage are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of rail vehicles, and particularly relates to a train wireless signal enhancement system and method. Background Art

[0002] With the rapid development of railway intelligent transportation, passengers' requirements for the quality of in-vehicle wireless signal coverage are increasing day by day. However, due to the characteristics of high-speed train operation, the wireless signals inside the carriage are often severely affected, which not only reduces the passengers' network usage experience but also affects the data communication security and stability on the train.

[0003] In the prior art, the methods to solve the communication problems on trains usually include enhancing the transmission power of base stations or access points (APs), and increasing the density of base stations or APs. Although these methods can improve signal coverage to a certain extent, due to their high costs and complex implementation, they are not conducive to large-scale promotion. Moreover, since they do not solve problems such as signal occlusion, multipath fading, and frequent base station handovers during the high-speed movement of trains, the enhancement effect on in-carriage wireless signals is limited, and the passengers' network usage experience is still difficult to guarantee. Summary of the Invention

[0004] An object of the present invention is to solve one of the above technical problems, and provide a train wireless signal enhancement system and method.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A train wireless signal enhancement system, characterized by comprising a central server, an AP device, an intelligent metasurface array, and a metasurface controller;

[0007] The central server is used to receive base station signals to connect to the Internet, perform communication data transmission with the AP device, send base station signal traffic to the AP device, and has the function of managing and configuring the AP device;

[0008] The AP device receives the base station signal traffic sent by the central server and transmits wireless signals to establish a wireless network coverage area inside the train carriage;

[0009] The intelligent metasurface array is used to receive the wireless signals emitted by the AP device and reflect the wireless signals according to the current reflection state to direct the wireless signals to the target area inside the carriage;

[0010] The metasurface controller is communicatively connected to the intelligent metasurface array, and is configured to receive the uplink sounding signal sent by the AP device, extract the signal features of the uplink sounding signal, generate metasurface configuration parameters with the goal of maximizing the signal-to-noise ratio based on the signal features, and send control signals to the intelligent metasurface array based on the metasurface configuration parameters to dynamically adjust the reflection state of the intelligent metasurface array.

[0011] In some embodiments of the present invention, the metasurface controller generates metasurface configuration parameters by running a regulation algorithm based on deep reinforcement learning;

[0012] The objective function of the regulation algorithm is defined as maximizing the signal-to-noise ratio:

[0013]

[0014] where P s is the power of the received signal, N O is the noise power, Ι is the interference power, and θ is the metasurface configuration parameter;

[0015] The state space of the regulation algorithm includes the signal amplitude A, signal phase φ, channel utilization rate η, interference power Ι, and signal strength Ρ of the channel;

[0016] The action space of the regulation algorithm includes the signal phase φ and signal amplitude A configuration parameters of each metasurface reflection unit;

[0017] The reward function R(θ) of the regulation algorithm is defined as:

[0018] R(θ) = SNR(θ) - SNR(θ prev );

[0019] where θ prev is the metasurface configuration parameter of the previous regulation period.

[0020] In some embodiments of the present invention, the central server receives 4G / 5G / 6G base station signals through the roof antenna, and sends the 4G / 5G / 6G base station signal traffic to the AP device by performing communication data transmission with the AP device.

[0021] In some embodiments of the present invention, both the central server and the AP device are wired to access the TCMS or PIS system vehicle switch, and data transmission is performed through the inter-carriage switch network.

[0022] In some embodiments of the present invention, data transmission is performed between the central server and the AP devices in each carriage through wireless bridging, and communication links are established between the AP devices in each carriage through wireless signals to achieve network interconnection between carriages.

[0023] In some embodiments of the present invention, the AP device periodically sends a channel status report to the metasurface controller; the metasurface controller generates metasurface configuration parameters based on the uplink sounding signal and the channel status report parameters.

[0024] In some embodiments of the present invention, the intelligent metasurface array is composed of multiple transparent conductive material units, the unit spacing between the transparent conductive material units is less than or equal to one quarter of the frequency band wavelength of the wireless signal in the carriage, and the phase adjustment range between the transparent conductive material units is 0 to 2π.

[0025] In some embodiments of the present invention, the intelligent metasurface array realizes the adjustment of amplitude and phase through a PIN diode switch.

[0026] In some embodiments of the present invention, the uplink sounding signal is a pseudo-random sequence or an orthogonal pilot sequence.

[0027] Some embodiments of the present invention further provide a method for enhancing train wireless signals, which is used to control the above-mentioned method for enhancing train wireless signals, and is characterized by including the following steps:

[0028] Deploy an AP device, an intelligent metasurface array and a metasurface controller inside the carriage;

[0029] The AP device is used to transmit wireless signals and establish a wireless network coverage area inside the train carriage; the AP device periodically sends an uplink sounding signal to the metasurface controller;

[0030] After receiving the wireless signal sent by the AP device, the intelligent metasurface array reflects the wireless signal based on its current reflection state to direct the wireless signal to the target area inside the carriage;

[0031] The AP device periodically sends an uplink sounding signal to the metasurface controller;

[0032] After receiving the uplink sounding signal sent by the AP device, the metasurface controller extracts the signal characteristics of the uplink sounding signal, generates metasurface configuration parameters with the goal of maximizing the signal-to-noise ratio based on the signal characteristics, and sends a control signal to the intelligent metasurface array based on the metasurface configuration parameters to dynamically adjust the reflection state of the intelligent metasurface array.

[0033] The beneficial effects of the present invention are as follows:

[0034] 1. By setting an intelligent metasurface array inside the train carriage to reflect the wireless signal sent by the AP device, and at the same time, dynamically adjusting the reflection state of the metasurface through the metasurface controller to direct the wireless signal to the target area inside the carriage, the present invention significantly improves the coverage range of the in-car wireless signal, optimizes the signal propagation path, reduces signal attenuation and multipath interference, and improves the signal strength and communication quality inside the carriage.

[0035] 2. The present invention adopts a regulation algorithm based on deep reinforcement learning, which can analyze the channel state in real time and dynamically adjust the metasurface configuration parameters with the goal of maximizing the signal-to-noise ratio, so that the reflection state of the intelligent metasurface array in the carriage can adapt to the complex channel environment of the personnel flow in the train, improve the stability and efficiency of signal transmission, reduce interference, and further optimize the passenger experience.

[0036] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained through the structures pointed out in the specification, claims, and drawings. Brief Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will describe the specific embodiments of the present invention in detail with reference to the drawings. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0038] Figure 1 It is a schematic structural diagram of a train wireless signal enhancement system;

[0039] Figure 2 It is a schematic deployment structure diagram of an AP device, an intelligent metasurface array, and a metasurface controller;

[0040] Figure 3 It is a schematic structural diagram of a wired network formed by a central server and an AP device;

[0041] Figure 4 It is a schematic structural diagram of a wireless network formed by a central server and an AP device. Detailed Embodiments

[0042] In order to make the objectives, technical solutions, and advantages of the present application clearer, the following will describe and explain the present application with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0044] In the case of no conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0045] The technical solutions of the present invention will be described in detail below in conjunction with specific embodiments and the accompanying drawings of the specification.

[0046] As shown in the attached Figure 1 - attached Figure 4 As shown, in a schematic embodiment of a train wireless signal enhancement system of the present invention, the system includes a central server, an AP device, an intelligent metasurface array, and a metasurface controller.

[0047] Among them, the central server configures 4G / 5G / 6G IoT cards, connects to the Internet through a feeder and a roof antenna to receive 4G / 5G / 6G base station signals; the central server communicates and transmits data with the AP device in a wired or wireless manner to send 4G / 5G / 6G base station signal traffic to the AP device; at the same time, the central server also has the function of managing and configuring the AP device.

[0048] The AP device receives the 4G / 5G / 6G base station signal traffic sent by the central server and emits a wireless signal to establish a wireless network coverage area in the train carriage, so that the mobile devices of passengers can search for and connect to the train wireless network. Specifically, the wireless signal emitted by the AP device is a WiFi signal.

[0049] The working frequency band supported by the AP device is 2.4 GHz to 5.8 GHz.

[0050] The AP device periodically sends an uplink detection signal to the metasurface controller.

[0051] The intelligent metasurface array includes a plurality of reflective RIS units, which are used to receive the wireless signal emitted by the AP device and reflect the wireless signal according to its current reflection state to direct the wireless signal to the target area in the carriage.

[0052] The metasurface controller (Control Unit), abbreviated as CU, consists of a central processor, a wireless module, a power module, a storage module, and a DAC control module. It is connected to the intelligent metasurface array via a control cable. The metasurface controller receives the uplink sounding signal sent by the AP device, extracts the signal characteristics of the uplink sounding signal, generates metasurface configuration parameters with the goal of maximizing the signal-to-noise ratio based on the signal characteristics, and sends control signals to the intelligent metasurface array based on the metasurface configuration parameters to dynamically adjust the reflection state of the intelligent metasurface array.

[0053] As shown in the Figure 1 attachment, in this system, the propagation link between the AP device and the user is a direct link, the propagation link between the AP device and the intelligent metasurface is a reflection link, the propagation link between the intelligent metasurfaces is a relay link, the propagation link between the intelligent metasurface and the user is a reflection link, and the propagation link between the AP device and the metasurface controller is a wireless control link.

[0054] The central server, the AP device, the intelligent metasurface array, and the metasurface controller are all deployed inside the train carriages.

[0055] Specifically, as shown in the Figure 2 attachment, the two ends in the length direction of the train are the 1-bit end and the 2-bit end respectively, and the two sides in the width direction are the 1-bit side and the 2-bit side respectively. Among them, the on-vehicle AP devices are installed at the top positions of the train at the 1-bit end and the 2-bit end of the carriage, namely AP1 and AP2 respectively; the intelligent metasurface arrays are installed on the windows and / or the carriage information display board positions on the 1-bit side and the 2-bit side of the train, namely RIS-1 to RIS-8 respectively, and the metasurface controllers are installed at the top positions of the train on the 1-bit side and the 2-bit side, namely RIS-1 to RIS-8 respectively, namely CU1 - CU8. As shown in the Figure 3 attachment Figure 4 and the attachment, the central server is installed in the control cabinets at the head and tail cars of the train, namely central server 1 and central server 2 respectively.

[0056] In some embodiments of the present invention, the AP device is also used to receive network requests sent by user devices (such as mobile phones, tablets, etc.) on the train and forward these requests to the central server. At the same time, the AP device will also receive the data returned by the central server and transmit it to the corresponding user device to achieve two-way data transmission.

[0057] In some embodiments of the present invention, the AP device periodically sends an uplink sounding signal to the metasurface controller. Due to the influence of the channel, there are differences between the received signal and the sent signal. The metasurface controllers CU1 / CU2 / CU3 / CU4 and CU5 / CU6 / CU7 / CU8 process the received AP1 and AP2 signals respectively.

[0058] The signal characteristics of the received signals extracted by the metasurface controller include amplitude, phase, and noise.

[0059] Among them, the metasurface controller extracts the amplitude information of the received signal for evaluating the signal strength, extracts the phase information of the received signal for evaluating the signal propagation path and phase offset, and estimates the noise level in the received signal for calculating the signal-to-noise ratio (SNR).

[0060] In some embodiments of the present invention, the uplink sounding signal is a pseudo-random sequence or an orthogonal pilot sequence.

[0061] In some embodiments of the present invention, the AP device also periodically sends a channel state report to the metasurface controller. The channel state report includes information such as channel utilization, interference level, and signal strength.

[0062] The metasurface controller generates metasurface configuration parameters based on the channel state report parameters and the signal characteristics of the uplink sounding signal.

[0063] Among them, the sending frequency of the channel state report can be adjusted according to actual needs. For example, it can be once per second or once per minute to ensure that the metasurface controller can obtain the latest channel state information in a timely manner. The channel state report can adopt a standardized format, such as JSON or XML, so that the metasurface controller can quickly parse and process it.

[0064] In some embodiments of the present invention, after receiving the uplink sounding signal and the channel state report sent by the AP device, the metasurface controller extracts the signal characteristics of the uplink sounding signal and the channel state report parameters, and generates metasurface configuration parameters with the goal of maximizing the signal-to-noise ratio based on the uplink sounding signal characteristics and the channel state report parameters.

[0065] In some embodiments of the present invention, the metasurface controller generates metasurface configuration parameters by running a regulation algorithm based on deep reinforcement learning.

[0066] Among them, the objective function of the regulation algorithm is defined as maximizing the signal-to-noise ratio:

[0067]

[0068] Among them, P s is the power of the received signal, N O is the noise power, Ι is the interference power, and θ is the metasurface configuration parameter.

[0069] The state space of the regulation algorithm includes the signal amplitude A, signal phase φ, channel utilization η, interference power Ι, and signal strength Ρ of the channel. The state space S is expressed as:

[0070] S = {A, φ, η, Ι, Ρ}.

[0071] Among them,

[0072] The signal amplitude A ∈ [0, Amax]: Normalized to [0, 1], with a resolution of 0.1 db;

[0073] The signal phase φ ∈ [0, 2π]: Quantized into 32 discrete intervals (each interval is 11.25°);

[0074] The channel utilization rate η ∈ [0, 1]: The ratio of the data frames successfully transmitted by the AP device within a unit time;

[0075] The interference power Ι ∈ [Imin, Imax]: Normalized to [0, 1];

[0076] The signal strength Ρ ∈ [-100, -30] dbm, which is the RSSI value received by the AP device from the user device, segmented into 5 levels (-100~-80, -80~-60, -60~-40, -40~-30 dBm).

[0077] The action space of the regulation algorithm includes the signal phase φ and signal amplitude A configuration parameters of each metasurface reflection unit. The action space A is expressed as:

[0078] A = {φ1, φ2,..., φ N , A1, A2,..., A N}.

[0079] Among them, φ i ∈ {0, π / 2, π, 3π / 2}, 4-bit phase quantization; A i ∈ {0, 0.5, 1}, three-level amplitude modulation.

[0080] For an N-element RIS, the total action space size is (4 * 3) N .

[0081] The reward function R(θ) of the regulation algorithm is defined as the improvement of the signal-to-noise ratio (SNR), that is:

[0082] R(θ) = SNR(θ) - SNR(θ prev ).

[0083] Among them, θ prev is the metasurface configuration parameter of the previous regulation period. When the signal-to-noise ratio increases, a positive reward is given; when the signal-to-noise ratio decreases, a negative reward is given. Through the reward function, the DRL algorithm is guided to optimize in the direction of maximizing the signal-to-noise ratio.

[0084] In some embodiments of the present invention, the central server is deployed in the control cabinets at the head and tail of the train, with a redundant switching function, and only one central server works at the same time.

[0085] In some embodiments of the present invention, as shown in the attached Figure 3 figure, both the central server and the AP devices are connected to the TCMS system or the PIS system vehicle switch through wired connections. In the case of wired connections, the central server and the AP devices transmit data through the switch network.

[0086] In some embodiments of the present invention, as shown in the attached Figure 4 figure, communication links are established between the wireless access point AP devices in each carriage through wireless signals. In the case of wireless bridging, data is transmitted between the central server and the AP devices in each carriage through wireless signals to achieve network interconnection between carriages.

[0087] In some embodiments of the present invention, the intelligent metasurface array is printed on the inner side of the window glass and is composed of multiple reflective RIS units made of highly transparent conductive materials. The unit spacing between the reflective RIS units is less than or equal to one-fourth of the wavelength of the wireless signal frequency band in the carriage, that is, the unit spacing ≤ λ / 4 (λ is the wavelength of the wireless frequency band), and the phase adjustment range between the reflective RIS units 1 is from 0 to 2π.

[0088] λ = C / f, where f is the frequency of the wireless signal and C is the speed of light. For example, 2.4 GHz corresponds to λ = 12.5 cm, and 5.8 GHz corresponds to λ = 5.2 cm.

[0089] In some embodiments of the present invention, the intelligent metasurface array is integrated at the position of the carriage surface display board and is composed of reflective RIS units using sub-wavelength metal patch arrays. The unit spacing between the reflective RIS units is less than or equal to one-fourth of the wavelength of the wireless signal frequency band in the carriage, that is, the unit spacing ≤ λ / 4 (λ is the wavelength of the wireless frequency band), and the phase adjustment range between the reflective RIS units 1 is from 0 to 2π.

[0090] In some embodiments of the present invention, the intelligent metasurface realizes the joint regulation of amplitude and phase through a PIN diode switch.

[0091] Some further embodiments of the present invention further provide a method for enhancing the train wireless signal, which is used to control the above-mentioned method for enhancing the train wireless signal, and includes the following steps.

[0092] Deploy a central server, AP devices, an intelligent metasurface array, and a metasurface controller inside the carriage. Among them, the central server is installed in the electrical cabinets at the head and tail carriages of the train, the on-vehicle AP devices are installed at the top positions of the 1st end and the 2nd end of the carriage, namely AP1 and AP2 respectively; the intelligent metasurface array is installed on the windows on the 1st side and the 2nd side of the train and / or at the position of the carriage information display board, namely RIS-1 to RIS-8 respectively, and the metasurface controller is installed at the top positions on the 1st side and the 2nd side of the train, namely CU1-CU8 respectively.

[0093] The central server is configured with 4G / 5G / 6G IoT cards and is connected to the roof antenna through a feeder. It can receive 4G / 5G / 6G base station signals to connect to the Internet, and can communicate and transmit data with the AP device in a wired or wireless manner, and has the function of managing and configuring the AP device.

[0094] The AP device receives the base station signal sent by the central server and emits a wireless signal, establishing a wireless network coverage area inside the train carriage, enabling passengers' mobile devices to search for and connect to the train wireless network. At the same time, the AP device receives network requests sent by user devices (such as mobile phones, tablets, etc.) on the train and forwards these requests to the central server. The AP device receives the data returned by the central server and transmits it to the corresponding user device to achieve two-way data transmission.

[0095] After receiving the wireless signal emitted by the AP device, the intelligent metasurface array reflects the wireless signal based on the current reflection state to direct the wireless signal to the target area inside the carriage. Among them, the reflection state includes phase and amplitude.

[0096] AP1 and AP2 respectively send a set of known uplink sounding signals to the metasurface controller periodically. The uplink sounding signal has a specific structure and characteristics, which can be a pseudo-random sequence or an orthogonal pilot sequence.

[0097] AP1 and AP2 respectively send channel state reports to the metasurface controller periodically. The channel state report includes information such as channel utilization, interference level, and signal strength.

[0098] Among them, the sending frequency of the channel state report can be adjusted according to actual needs. For example, once per second, to ensure that the metasurface controller can obtain the latest channel state information in a timely manner. The channel state report can adopt a standardized format, such as JSON or XML, so that the metasurface controller can quickly parse and process it.

[0099] The metasurface controllers CU1 / CU2 / CU3 / CU4 and CU5 / CU6 / CU7 / CU8 respectively process the signals received from AP1 and AP2, and extract the characteristics of the signals, such as amplitude, phase, and noise estimation.

[0100] The metasurface controllers CU1 / CU2 / CU3 / CU4 and CU5 / CU6 / CU7 / CU8 respectively process the channel state reports of AP1 and AP2 received, and extract the channel utilization, interference level, and signal strength.

[0101] The metasurface controller generates metasurface configuration parameters with the goal of maximizing the signal-to-noise ratio based on the extracted signal characteristics and channel state report parameters.

[0102] The metasurface controller sends control signals to the intelligent metasurface array through a control cable based on the metasurface configuration parameters to dynamically adjust the reflection states of the reflection units in the intelligent metasurface array and optimize the signal propagation path.

[0103] After the metasurface controller calculates the required amplitude and phase of the reflected signal according to the algorithm, it will output the corresponding bias voltage through the DAC module to drive the PIN diode into a suitable working state, achieve precise control of its equivalent impedance, and then realize the regulation of the amplitude and phase of the reflected signal.

[0104] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0105] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features. Without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. A train wireless signal enhancement system, characterized in that, It includes an AP device, an intelligent metasurface array, and a metasurface controller; The AP device is used to transmit wireless signals and establish a wireless network coverage area inside the train carriage; the AP device periodically sends an uplink sounding signal to the metasurface controller; The intelligent metasurface array is used to receive the wireless signals emitted by the AP device and reflect the wireless signals according to its current reflection state, so as to direct the wireless signals to the target area inside the carriage; The metasurface controller is communicatively connected to the AP device, and is used to receive the uplink sounding signal sent by the AP device, extract the signal characteristics of the uplink sounding signal, generate metasurface configuration parameters with the goal of maximizing the signal-to-noise ratio based on the signal characteristics, and send control signals to the intelligent metasurface array based on the metasurface configuration parameters to dynamically adjust the reflection state of the intelligent metasurface array.

2. The train wireless signal enhancement system according to claim 1, characterized in that, The metasurface controller generates metasurface configuration parameters by running a regulation algorithm based on deep reinforcement learning; The objective function of the regulation algorithm is defined as maximizing the signal-to-noise ratio: Among them, P s is the power of the received signal, N O is the noise power, Ι is the interference power, and θ is the metasurface configuration parameter; The state space of the regulation algorithm includes the signal amplitude A, signal phase φ, channel utilization rate η, interference power Ι, and signal strength Ρ of the channel; The action space of the regulation algorithm includes the signal phase φ and signal amplitude A configuration parameters of each metasurface reflection unit; The reward function R(θ) of the regulation algorithm is defined as: R(θ) = SNR(θ) - SNR(θ prev ) where θ prev is the metasurface configuration parameter of the up-regulation period.

3. The train wireless signal enhancement system according to claim 1 or 2, characterized in that It further includes a central server, which receives the base station signal through an antenna, is communicatively connected to the AP device, and forwards the base station signal traffic to the AP device.

4. The train wireless signal enhancement system according to claim 3, wherein Both the central server and the AP device are wired to access the vehicle switch and perform data transmission through the switch network.

5. The train wireless signal enhancement system according to claim 3, characterized in that Data transmission is carried out between the central server and the AP devices in each carriage through wireless signals, and communication links are established between the AP devices in each carriage through wireless signals to achieve network interconnection between carriages.

6. The train wireless signal enhancement system according to claim 1 or 2, characterized in that, The AP device periodically sends a channel status report to the metasurface controller; the metasurface controller generates metasurface configuration parameters based on the channel status report parameters and the uplink sounding signal.

7. The train wireless signal enhancement system according to claim 1, wherein The uplink sounding signal is a pseudo-random sequence or an orthogonal pilot sequence.

8. The train wireless signal enhancement system according to claim 1 or 2, characterized in that, The intelligent metasurface array is composed of multiple transparent conductive material units, and the unit spacing between the transparent conductive material units is less than or equal to one quarter of the wavelength of the wireless signal frequency band inside the carriage; the phase regulation range between the transparent conductive material units is from 0 to 2π.

9. The train wireless signal enhancement system according to claim 1 or 2, characterized in that, The intelligent metasurface array realizes the regulation of amplitude and phase through PIN diode switches.

10. A method for enhancing train wireless signals, which is used to control the train wireless signal enhancement system according to any one of claims 1-9, characterized in that, It includes the following steps: Deploy an AP device, an intelligent metasurface array, and a metasurface controller inside the carriage; The AP device emits wireless signals and establishes a wireless network coverage area inside the train carriage; The intelligent metasurface array receives the wireless signals emitted by the AP device and reflects the wireless signals based on its current reflection state, so as to direct the wireless signals to the target area inside the carriage; The AP device periodically sends an uplink sounding signal to the metasurface controller; After receiving the uplink sounding signal sent by the AP device, the metasurface controller extracts the signal features of the uplink sounding signal, generates metasurface configuration parameters with the goal of maximizing the signal-to-noise ratio based on the signal features, and sends a control signal to the intelligent metasurface array based on the metasurface configuration parameters to dynamically adjust the reflection state of the intelligent metasurface array.

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