Method and system for improving spectrum availability of Internet of Vehicles, and electronic equipment

Abstract

The invention provides a method and a system for improving spectrum availability of Internet of Vehicles, and electronic equipment, and the method comprises the steps: building a road model comprising a viaduct and high-rise buildings at two sides of the viaduct, and classifying an area where a main user is located according to a signal receiving characteristic; estimating the geometric boundary of the area where each type of main user is located by taking the position and distance between the viaduct and the high-rise building, the position and distance between the viaduct and the ground road and the antenna position of the vehicle terminal as factors; based on the geometric boundary, a dual-path propagation model is adopted, and interference power from a secondary user transmitter to a primary user receiver in the area where each type of primary user is located is calculated; the interference power is enabled to be within a certain range by adjusting the parameters influencing the interference power in the area where each primary user is located, so that the frequency spectrums of the primary users and the secondary users in the area are shared.

Description

Technical Field

[0001] The present invention belongs to the field of Internet of Vehicles applications, and particularly relates to a method, system and electronic device for improving spectrum availability in the Internet of Vehicles. Background Art

[0002] With the rapid development of the Internet of Vehicles (IoV), non-safety-related services such as entertainment and gaming have become increasingly important in IoV. In addition, high data-intensive sensors (such as LiDAR and cameras) used in autonomous vehicles generate a large amount of data, further exacerbating the scarcity of spectrum resources.

[0003] Cognitive Radio (CR) technology provides an effective solution to alleviate the scarcity of spectrum resources and is a key component in the development of the fifth-generation mobile communication (5G). CR technology improves spectrum efficiency by allowing Primary Users (PUs) and Secondary Users (SUs) to coexist. In CR-assisted Internet of Vehicles (CIoV), spectrum overlay and underlay technologies enable PUs and SUs to share spectrum resources, thus optimizing spectrum utilization.

[0004] Although a large amount of research has focused on aspects such as spectrum sensing, access, allocation, and sharing in CIoV, obtaining more stable spectrum opportunities remains a major challenge. Existing research mainly focuses on vehicle and cognitive radio channel models, but there has been no research specifically targeting the situation where both the direct path and the reflected path from the SU transmitter (SU-Tx) to the PU receiver (PU-Rx) in CIoV are blocked by a viaduct structure. Due to the presence of obstacles (viaduct structure), the interference power from SU-Tx to PU-Rx can be significantly reduced. If the interference power is below the interference threshold of the PU, then the SU and the PU can occupy the same channel simultaneously.

[0005] In summary, although the existing technology has made certain progress in spectrum management and utilization, there are still deficiencies in improving spectrum availability. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: to provide a method, system and electronic device for improving spectrum availability in the Internet of Vehicles, and to improve spectrum utilization.

[0007] The technical solution adopted by the present invention to solve the above technical problem is: a method for improving spectrum availability in the Internet of Vehicles, the method comprising the following steps: S1. Establish a road model including the viaduct and high-rise buildings on both sides of the viaduct. The vehicle distribution on the viaduct and the ground road under the viaduct is sparse, and each channel can only be accessed by one secondary user at a time. The secondary users are vehicle terminals on the ground road under the viaduct, and the primary users are radio terminals located in high-rise buildings. Classify the areas where the primary users are located according to signal reception characteristics. S2. Take the positions and distances between the viaduct and high-rise buildings, the viaduct and the ground road, and the antenna positions of vehicle terminals as factors to estimate the geometric boundaries of the areas where each type of primary user is located. S3. Based on the geometric boundaries, adopt a two-path propagation model to calculate the interference power from the secondary user transmitter to the primary user receiver in the areas where each type of primary user is located, respectively. S4. By adjusting the parameters that affect the interference power in the areas where each primary user is located, the interference power is made to be within a certain range, so that the spectrum of the primary users and secondary users in this area can be shared.

[0008] According to the above method, the areas where the primary users are located are specifically divided into: Direct line-of-sight area: including the area where neither the direct path nor the reflected path is blocked by the viaduct. Direct non-line-of-sight area: including the area where the direct path penetrates the surface of the viaduct and the reflected path is not blocked by the viaduct. Reflected non-line-of-sight area: the area where both the direct path and the reflected path penetrate the surface of the viaduct.

[0009] According to the above method, the geometric boundary of the direct line-of-sight area is calculated by abstracting the road model into a two-dimensional geometric projection and using the principle of similar triangles.

[0010] According to the above method, based on the height of the geometric boundary of the direct line-of-sight area, use geometric relationships to determine the heights of the geometric boundaries of the direct non-line-of-sight area and the reflected non-line-of-sight area, respectively.

[0011] According to the above method, the calculation of the interference power specifically includes: Calculate the reflection coefficient and transmission coefficient of vertical polarization, and the reflection coefficient and transmission coefficient of horizontal polarization in the areas where each primary user is located, respectively. Calculate the interference power of vertical polarization based on the reflection coefficient and transmission coefficient of vertical polarization. Calculate the interference power of horizontal polarization based on the reflection coefficient and transmission coefficient of horizontal polarization.

[0012] According to the above method, in the road model, there are two traffic flows on the viaduct and one traffic flow under the viaduct, and the distributions of the two traffic flows follow the Poisson distribution.

[0013] According to the above method, the antenna of the vehicle terminal includes a transmitting antenna and a receiving antenna, and the signal propagation follows the log-distance path loss model.

[0014] According to the above method, the parameters affecting the interference power include the height of the viaduct, the distance between the viaduct and the high-rise buildings on both sides, and the height of the antenna of the vehicle terminal.

[0015] A system for improving spectrum availability in a vehicle-to-everything (V2X) network, the system comprising: A model establishment module, configured to establish a road model including a viaduct and high-rise buildings on both sides of the viaduct, wherein the vehicle distribution on the ground roads above and below the viaduct is sparse, and each channel can only be accessed by one secondary user at the same time; the secondary user is a vehicle terminal on the ground road under the viaduct, the primary user is located in the high-rise building, and the area where the primary user is located is classified according to the signal reception characteristics; A geometric boundary calculation module, configured to estimate the geometric boundaries of the areas where each type of primary user is located by taking the positions and distances between the viaduct and the high-rise buildings, the viaduct and the ground road, and the antenna position of the vehicle terminal as factors; An interference power calculation module, configured to calculate the interference power from the secondary user transmitter to the primary user receiver in the area where each type of primary user is located respectively based on the geometric boundaries by using a two-path propagation model; A parameter adjustment module, configured to adjust the parameters affecting the interference power in the area where each primary user is located, so that the interference power is within a certain range, so that the spectrum of the primary user and the secondary user in this area can be shared.

[0016] An electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method for improving spectrum availability in the vehicle-to-everything network are implemented.

[0017] The beneficial effects of the present invention are as follows: 1. By using the shielding effect of the urban viaduct for modeling, the areas where the primary users are located are divided into three types, the boundaries of each area are estimated, and then a two-path propagation model is introduced to more accurately calculate the interference power from the secondary user transmitter to the primary user receiver. By adjusting the parameters affecting the interference power, the spectrum resources are optimized and the spectrum utilization rate is improved.

[0018] 2. By abstracting the road model into a two-dimensional geometric projection and using the principle of similar triangles to estimate the boundaries of the area, and then better dividing the area, a more accurate parameter basis is provided for calculating the interference power, so as to identify the available spectrum opportunities and provide additional spectrum opportunities for the secondary users in the vehicle-to-everything network. Description of the Drawings

[0019] Figure 1 It is a flowchart of the method according to an embodiment of the present invention.

[0020] Figure 2 It is a schematic diagram of the geometric boundary principle according to an embodiment of the present invention.

[0021] Figure 3 It is for different in the geometric boundary diagrams according to an embodiment of the present invention.

[0022] Figure 4 It is for different values in the geometric boundary diagrams according to an embodiment of the present invention.

[0023] Figure 5 It is for different values in the geometric boundary diagrams according to an embodiment of the present invention.

[0024] Figure 6 It is for different values in the geometric boundary diagrams according to an embodiment of the present invention.

[0025] Figure 7 It is the interference power diagram from SU-Tx to PU-Rx for different values according to an embodiment of the present invention.

[0026] Figure 8 It is the interference power diagram from SU-Tx to PU-Rx for different values according to an embodiment of the present invention.

[0027] Figure 9 It is the interference power diagram from SU-Tx to PU-Rx for different values according to an embodiment of the present invention.

[0028] Figure 10 It is the interference power diagram from SU-Tx to PU-Rx for different values according to an embodiment of the present invention.

[0029] In the figure: 1 - ground road, 2 - viaduct, 301 - high-rise building on the left, 302 - high-rise building on the right, 4 - antenna. Detailed implementation manners

[0030] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] Glossary: Channel: The path through which a signal is transmitted in a communication system, which is the transmission medium through which a signal travels from the transmitting end to the receiving end.

[0032] Direct path: The area of the signal transmitted without being blocked by a structure (viaduct).

[0033] Reflection path: The area of the signal transmitted after being blocked by a structure (viaduct).

[0034] The present invention provides a method for improving spectrum availability in a vehicle-to-everything (V2X) network. As Figure 1 shown, the method includes the following steps: S1. Establish a road model including a viaduct and high-rise buildings on both sides of the viaduct, where the vehicle distribution on the ground road above and below the viaduct is sparse, and each channel can only be accessed by one secondary user at the same time; the secondary user is a vehicle terminal on the ground road under the viaduct, and the primary user is a radio terminal located in the high-rise building, and classify the area where the primary user is located according to the signal reception characteristics.

[0035] Specifically, the area where the primary user is located is specifically divided into: Direct line-of-sight area (Area 1): including the area where neither the direct path nor the reflection path is blocked by the viaduct; Direct non-line-of-sight area (Area 2): including the area where the direct path penetrates the surface of the viaduct and the reflection path is not blocked by the viaduct; Reflection non-line-of-sight area (Area 3): the area where both the direct path and the reflection path penetrate the surface of the viaduct.

[0036] The construction of urban viaducts helps to alleviate traffic congestion in large modern cities. At the same time, its shielding effect may provide additional spectrum opportunities for vehicles for data transmission. Specifically, when the SU vehicle is located under the viaduct and the PUs are located on the upper floors of nearby buildings, if the active PUs are located in the shadow areas (Area 2 and Area 3), the SU vehicle can access the same spectrum without causing harmful interference to the transmission of the PUs.

[0037] The road model constructed in this embodiment is a double-layer single-lane road model. As Figure 2 shown, the model includes a ground road 1, a viaduct 2, a left high-rise building 301 and a right high-rise building 302 on the left side of the viaduct. There are two traffic flows on the viaduct 2 and one traffic flow under the viaduct 2. The distribution of these two different traffic flows follows a Poisson distribution, and its mean value is equal to the linear density multiplied by λ the perimeter. Assume that the vehicle distribution on the road is sparse, and each channel can only be accessed by one secondary user (SU) at the same time to avoid interference and ensure spectrum utilization efficiency. The width of the viaduct is denoted as W B , and the height is denoted as h BTV users in residential buildings on both sides of the viaduct are regarded as primary users (PUs), while vehicles on the lane are secondary users (SUs).

[0038] Based on the above model, a three-dimensional space is constructed with the coordinate origin set at the position of the vehicle. x The z-axis is perpendicular to the vehicle driving direction, y the x-axis is parallel to the vehicle moving direction, z and the y-axis is perpendicular to the ground. The horizontal distance between the transmission antenna of the vehicle terminal and the viaduct deck axis is denoted as , and its coordinates are ([[-END]] - , 0 , 0), as Figure 2 shown. The projected height represents the shadow height projected on the ground when the SU-Tx signal penetrates the viaduct, and this height is denoted as h , and its coordinates are represented as (0 , 0 , h ).

[0039] In the communication model, the height of the vehicle antenna is denoted as , and its coordinates are (0 , 0 , ). The transmit antenna gain and receive antenna gain are denoted as G t and G r . Assume that all transmissions are omnidirectional and the signal propagation follows the log-distance path loss model. As Figure 2 shown, due to the existence of the viaduct (obstacle), there will be specific shadow areas and line-of-sight (LOS) areas between SU-Tx and PU-Rx. Under the non-line-of-sight (NLOS) conditions in the shadow area, the signal is blocked and can only reach the receiver through reflection, diffraction, or scattering. The spectrum sensing device of CIoV is located on the viaduct to monitor and analyze the spectrum usage of the primary user (PU) in real time. The CIoV network uses two main spectrum access mechanisms: overlay and downlink. In this case, downlink is the preferred solution. Different from overlay which requires accurate knowledge of PU activities and may cause delays in waiting for spectrum clearance, downlink allows secondary users (SUs) to transmit at any time. This ensures that the transmission of the PU is not affected while the SUs can communicate. Whether there will be an impact can be determined by calculating the interference power Pr from SU-Tx to PU-Rx.

[0040] S2. Taking the positions and distances between the viaduct and high-rise buildings, the viaduct and ground roads, and the antenna position of the vehicle terminal as factors, estimate the geometric boundaries of the areas where each type of primary user is located.

[0041] The geometric boundary refers to the dividing line that separates different regions based on signal propagation characteristics, such as whether the signal propagates along a direct line-of-sight (LOS) path, a non-line-of-sight (NLOS) path, or a reflected path.

[0042] To reduce computational complexity, the three-dimensional model is transformed into a two-dimensional projection model for calculation. We assume that the vehicle is moving on a fixed lane under the viaduct. Therefore, the x-axis and z-axis remain unchanged, while the value on the y-axis changes as the vehicle moves. Thus, the above three-dimensional system model is abstracted into a corresponding two-dimensional scenario. This model better reflects how the positions of the vehicle SUs change and how interference affects signal transmission, by including moving parts such as vehicle speed, position changes, and traffic flow changes. The adaptive algorithm enables the SUs to adjust the power output in real time to account for the changing environment in various scenarios.

[0043] The present invention uses similar triangles and formulates parametric equations to abstract the three-dimensional model into two dimensions. Then these equations are used to determine the boundaries of the three regions. As Figure 2 shown, h 1 and h 2 respectively represent the boundary heights of Region 1 of the high-rise building on the left and the high-rise building on the right, h 3 and h 4 respectively represent the boundary heights of Region 2 of the high-rise building on the left and the high-rise building on the right, while h 5 and h 6 respectively represent the boundary heights of Region 3 of the high-rise building on the left and the high-rise building on the right.

[0044] In the figure, point O is the position of the transmission antenna of the vehicle terminal; J is the intersection point of the transmitting antenna at point O with the leftmost side of the viaduct during the transmission of the signal, and JK is the distance between the viaduct and the vehicle antenna; OG is the horizontal distance between the vehicle antenna and the left building, and OB is the horizontal distance between the vehicle antenna and the right building; GF is the maximum projection height of the vehicle antenna signal projected onto the left building without being affected by the viaduct, and BC is the maximum projection height of the vehicle antenna signal projected onto the right building without being affected by the viaduct; OF is the maximum path distance of the vehicle antenna signal transmitted to the left building without being affected by the viaduct, and OC is the maximum path distance of the vehicle antenna signal transmitted to the right building without being affected by the viaduct; FE is h the height range of h 3, and CI is

[0045] According to the theory of similar triangles, obviously △OFG ∼△OJK . Therefore, h 1 andh 2 can be calculated as follows:

[0046]

[0047]

[0048]

[0049] where the subscript x refers to the horizontal distance, and the subscript z refers to the vertical distance; is the height of the viaduct; is the height of the vehicle antenna, the vertical distance from the ground to the vehicle antenna; is the vertical height of the signal blockage effect of the viaduct, that is, the vertical projection height from the vehicle antenna to the left building without being blocked by the viaduct; is the horizontal distance from the vehicle to the center of the viaduct, the horizontal line segment from the vehicle position to the center of the viaduct; is the unblocked vertical height from the bottom of the viaduct to the top of the right building; is the horizontal distance from one side of the viaduct to the nearest building, the horizontal line segment from the edge of the viaduct to the building; is the width of the viaduct, the horizontal distance from one side of the viaduct to the other side.

[0050] Based on the calculated and , the boundary heights and are determined using geometric relationships.

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] Similarly, the boundary heights and are calculated using geometric relationships.

[0059]

[0060]

[0061] wherein, is the height of the building.

[0062] S3. Based on the geometric boundary, adopt a two-path propagation model to calculate the interference power from the secondary user transmitter to the primary user receiver in the area where each type of primary user is located.

[0063] The calculation of the interference power specifically includes: calculating the reflection coefficient and transmission coefficient of vertical polarization and the reflection coefficient and transmission coefficient of horizontal polarization in the area where each primary user is located respectively; calculating the interference power of vertical polarization based on the reflection coefficient and transmission coefficient of vertical polarization; calculating the interference power of horizontal polarization based on the reflection coefficient and transmission coefficient of horizontal polarization.

[0064] In this embodiment, a two-path propagation model is adopted to calculate the interference power from the SU transmitter (SU-Tx) to the PU receiver (PU-Rx), considering the reflection and penetration coefficients of vertical and horizontal polarizations.

[0065] Vertical polarization:

[0066]

[0067] In the formula: is the incident angle, such as Figure 2 ∠FOG in is the refraction angle, such as Figure 2 ∠COB in , , , are obtained through trigonometric functions; is the loss when the signal penetrates the obstacle (such as a viaduct) in the vertical polarization state, which considers the energy loss during the penetration process of the signal; is the loss when the signal is reflected from the obstacle in the vertical polarization state, which describes the proportion of the signal reflected back when encountering the obstacle.

[0068] Horizontal polarization:

[0069]

[0070] In the formula: is the reflection coefficient of horizontal polarization, is the transmission coefficient of horizontal polarization, is the refractive index of the interface air, are the refractive indices of the high-rise buildings on the left and right sides.

[0071] Interference power formula for Region 1:

[0072] where, is the interference power of Region 1, that is, the power received by the primary user in Region 1 from the secondary user's transmitting antenna. This parameter is one of the key indicators for evaluating the possible interference caused by the SU to the PU. is the transmission power, and are the transmitting and receiving antenna gains respectively, is the wavelength, is the distance, is the system loss factor.

[0073] Interference power of Region 2:

[0074]

[0075] Interference power of Region 3:

[0076]

[0077] where, is the interference power of the vertically polarized signal in Region 2, is the interference power of the horizontally polarized signal in Region 2; is the interference power of the vertically polarized signal in Region 3, is the interference power of the horizontally polarized signal in Region 3; represents the loss when the signal penetrates an obstacle (such as a viaduct) in the vertically polarized state, which takes into account the energy loss during the penetration process; represents the loss when the signal is reflected from an obstacle in the vertically polarized state, which describes the proportion of the signal reflected back when encountering an obstacle; is similar to and represents the loss when the signal penetrates an obstacle in the horizontally polarized state; is similar to and represents the loss when the signal is reflected from an obstacle in the horizontally polarized state.

[0078] S4. By adjusting the parameters that affect the interference power in each region where the primary user is located, so that the interference power is within a certain range, thus enabling the sharing of the spectrum between the primary user and the secondary user in that region.

[0079] In this embodiment, assume that the width of the viaduct deck is 30 m, the road width is 15 m, the bridge deck height is 5 m, the total height of the building is 120 m, the height of the receiving antenna is 120 m, and the horizontal distance between the receiving antenna and the left side of the bridge is 20 m. In this scenario, the geometric boundaries of each region are determined through a parametric geometric model. The results show that within Region 1, the interference of the SU to the PU is the greatest; while within Region 2 and Region 3, the interference is the smallest or there is no interference. By adjusting the parameters, the spectrum utilization rate can be further optimized. The relevant tables are shown in Table 1 - Table 5, and Figures 3 - 10 , through MATLAB simulation, the changes in the geometric boundaries and interference power of each region under different variables are demonstrated. Among them and define the upper and lower boundaries of Region 1, that is, the receiving region of the direct LOS signal and the reflected LOS signal. Within this region, the signal can directly reach the PU-Rx from the SU-Tx without being blocked by the viaduct; and define the upper and lower boundaries of Region 2, that is, the receiving region of the direct NLOS signal. Within this region, the direct path is blocked by the viaduct, and the signal can only reach the PU-Rx through reflection on the surface of the viaduct; and define the upper and lower boundaries of Region 3, that is, the receiving region of the reflected NLOS signal. Within this region, the signal needs to penetrate the surface of the viaduct to reach the PU-Rx.

[0080] Table 1 shows that as the vehicle approaches the viaduct, the coverage ranges of Region 1 and Region 3 expand, while the coverage range of Region 2 expands before a certain point and then shrinks, indicating that the blocking effect of the viaduct is more significant when the vehicle approaches, providing more spectrum opportunities for the vehicle, especially in Region 1 and Region 3; Table 2 shows that as the height of the vehicle antenna increases, the coverage ranges of Region 1 and Region 3 expand, while the coverage range of Region 2 shrinks, indicating that by increasing the height of the vehicle antenna, Regions 1 and 3 can be effectively utilized for communication, thereby improving the spectrum utilization rate; Table 3 shows that as the width of the viaduct decreases, the coverage range of Region 1 shrinks, while the coverage ranges of Region 2 and Region 3 expand, indicating that by reducing the width of the viaduct, Regions 2 and 3 can be effectively utilized for communication, thereby improving the spectrum utilization rate; Table 4 shows that as the height of the viaduct increases, the coverage range of Region 1 expands, while the coverage ranges of Region 2 and Region 3 shrink, indicating that by increasing the height of the viaduct, Region 1 can be effectively utilized for communication, thereby improving the spectrum utilization rate; Table 5 shows the electromagnetic parameters of different materials at specific frequencies.

[0081] Table 1 Influence on the heights of different regions

[0082] Table 2 Influence on the height of different regions

[0083] Table 3 Influence on the height of different regions

[0084] Table 4 Influence on the height of different regions

[0085] Table 5 Material parameters at different frequencies

[0086] Appendix Figures 3 - 6 Shows the influence of different parameters on the size of the signal propagation region. Appendix Figures 7 - 10 Displays the distribution of the geometric boundaries of each region at different viaduct heights and distances and shows the variation of the interference power within each region with distance under the same conditions.

[0087] Through research and analysis, it is found that within Region 1, due to the direct path between the SU and the PU being blocked by the viaduct, the interference from the SU to the PU is relatively large. However, through reasonable design and parameter adjustment, the transmission of the SU can be restricted within this region to avoid causing harmful interference to the PU. For example: by adjusting the height, width, and distance of the viaduct, etc., the spectrum utilization rate can be further optimized, interference can be reduced, and communication quality can be improved. Specific strategies that can be implemented include: appropriately increasing the height of the viaduct to reduce direct line-of-sight signal interference, while optimizing the width of the viaduct to balance the distribution of the direct line-of-sight and reflected signal regions; by dynamically adjusting the vehicle position and antenna height, the vehicle can preferentially use reflected or penetrating signals for communication; in the viaduct design, an optimized bridge deck material and structural layout can be selected to enhance the intensity of the reflected signal, thereby improving the spectrum utilization efficiency and reducing interference to primary users.

[0088] Within Region 2 and Region 3, due to the existence of reflection paths and penetration paths, the interference from the SU to the PU is relatively small or even non-existent. Therefore, these regions are ideal locations suitable for SU transmission.

[0089] Furthermore, for the affected PUs, a dynamic spectrum allocation strategy is implemented, allowing for flexible adjustment of spectrum usage according to real-time channel conditions and interference levels to ensure that the communication of PUs is not affected. Specific measures include, for example: real-time monitoring of the channel usage and interference levels of PUs through cognitive radio, preferentially allocating clean channels or frequency bands; dynamically adjusting the transmission power or channels of SUs to reduce interference to PUs; reserving backup channels for PUs and performing channel switching under high interference conditions; optimizing resource allocation by combining distributed spectrum management and adjusting the spectrum usage of PUs and SUs according to real-time conditions; at the same time, ensuring the communication stability and priority of PUs through dynamic allocation of spectrum idle time slots.

[0090] As a second aspect of the present invention, the present invention also provides a system for improving spectrum availability in an Internet of Vehicles, which system comprises: A model establishment module, configured to establish a road model including a viaduct and high-rise buildings on both sides of the viaduct, wherein the vehicle distribution on the viaduct and the ground road under the viaduct is sparse, and each channel can only be accessed by one secondary user at the same time; the secondary user is a vehicle terminal on the ground road under the viaduct, the primary user is located in the high-rise building, and the area where the primary user is located is classified according to the signal reception characteristics. A geometric boundary calculation module, configured to estimate the geometric boundaries of the areas where each type of primary user is located by taking into account the positions and distances between the viaduct and the high-rise buildings, the viaduct and the ground road, and the antenna positions of the vehicle terminals. An interference power calculation module, configured to calculate, based on the geometric boundaries and using a two-path propagation model, the interference power from the secondary user transmitter to the primary user receiver in the areas where each type of primary user is located. A parameter adjustment module, configured to adjust the parameters affecting the interference power in the areas where each primary user is located, so that the interference power is within a certain range, thereby enabling the sharing of the spectrum between the primary users and the secondary users in these areas.

[0091] As a third aspect of the present invention, the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method for improving spectrum availability in the Internet of Vehicles are implemented.

[0092] The present invention utilizes the shielding effect of urban viaducts to provide additional spectrum opportunities for a cognitive radio-assisted Internet of Vehicles (CIoV) in the Internet of Vehicles (IoV), thereby significantly improving the availability of spectrum resources and the overall spectrum utilization rate. Compared with the prior art, the present invention has the following technical advantages and beneficial effects: 1. Improve the utilization efficiency of spectrum resources: By dividing the PU region into three types and proposing a parametric geometric model to estimate the geometric boundaries of each region type, the available spectrum opportunities are identified. This precise regional division enables secondary users (SUs) to utilize spectrum resources more effectively, thereby improving the overall utilization efficiency of spectrum resources.

[0093] 2. Enhance the efficiency of spectrum utilization: The dual-path propagation model is introduced to calculate the interference power from the SU transmitter (SU-Tx) to the PU receiver (PU-Rx), considering the reflection and penetration coefficients of vertical and horizontal polarizations. Through precise modeling and simulation, spectrum resources can be managed and optimized more effectively, improving the overall spectrum utilization efficiency. Specifically, through MATLAB simulation, the variations of the geometric boundaries and interference power of each region under different variables are demonstrated, thus ensuring the high efficiency of spectrum use.

[0094] 3. Optimization for specific environments: Specifically, the research on the shielding effect of urban viaducts is carried out, and new parametric geometric models and dual-path propagation models are proposed. These models can better adapt to the signal propagation characteristics in the urban viaduct environment, thereby achieving more precise spectrum management and optimization. Through case studies, it is verified that under specific conditions, the transmission of SUs will not cause harmful interference to PUs, thus improving the reliability and stability of the system.

[0095] 4. Enhance the interference control ability: Through the dual-path propagation model and case studies, interference is evaluated and controlled more accurately. Two case studies are carried out with actual parameters, and it is verified that under specific conditions, the transmission of SUs will not cause harmful interference to PUs. In addition, through extensive numerical analysis, the influence of different parameters on the interference from SU-Tx to PU-Rx in each region type is studied, providing a more accurate interference control method. This not only improves the reliability of the system but also reduces unnecessary interference and improves the communication quality.

[0096] 5. Dynamic spectrum allocation strategy: A dynamic spectrum allocation strategy is proposed, which allows flexible adjustment of spectrum use according to real-time channel conditions and interference levels, ensuring that the communication of PUs is not affected while maximizing the spectrum utilization efficiency of SUs. This dynamic adjustment strategy makes the utilization of spectrum resources more efficient and flexible. Through the dynamic spectrum allocation strategy, while ensuring the communication quality of PUs, the spectrum resources can be utilized to the maximum extent, improving the overall performance of the system and the user experience.

[0097] In summary, the present invention solves the problems of scarce spectrum resources, low spectrum utilization efficiency, lack of optimization for specific environments, and insufficient interference control in the prior art by utilizing the shielding effect of urban viaducts. The present invention not only improves the spectrum availability and overall spectrum utilization rate in the vehicle-to-everything (V2X) network, but also provides more reliable communication guarantees for future V2X applications.

[0098] It should be understood that those of ordinary skill in the art can make improvements or transformations according to the above description, and all such improvements and transformations shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for improving spectrum availability in a vehicle-to-everything (V2X) network, characterized in that: The method includes the following steps: S1. Establish a road model including a viaduct and high-rise buildings on both sides of the viaduct. The vehicle distribution on the viaduct and the ground road under the viaduct is sparse, and each channel can only be accessed by one secondary user at the same time. The secondary user is the vehicle terminal on the ground road under the viaduct, and the primary user is the radio terminal located in the high-rise building. Classify the area where the primary user is located according to the signal reception characteristics; S2. Take the position and distance between the viaduct and the high-rise building, the viaduct and the ground road, and the antenna position of the vehicle terminal as factors, and estimate the geometric boundary of the area where each type of primary user is located; S3. Based on the geometric boundary, adopt a two-path propagation model to calculate the interference power from the secondary user transmitter to the primary user receiver in the area where each type of primary user is located; S4. By adjusting the parameters that affect the interference power in the area where each primary user is located, so that the interference power is within a certain range, so that the spectrum of the primary user and the secondary user in this area can be shared.

2. The method for improving spectrum availability in a vehicle-to-everything (V2X) network according to claim 1, wherein: The area where the primary user is located is specifically divided into: Direct line-of-sight area: including the area where neither the direct path nor the reflected path is blocked by the viaduct; Direct non-line-of-sight area: including the area where the direct path penetrates the surface of the viaduct and the reflected path is not blocked by the viaduct; Reflected non-line-of-sight area: the area where both the direct path and the reflected path penetrate the surface of the viaduct.

3. The method for improving spectrum availability in a vehicle-to-everything network according to claim 2, characterized in that: The geometric boundary of the direct line-of-sight area is calculated by abstracting the road model into a two-dimensional geometric projection and using the principle of similar triangles.

4. The method for improving spectrum availability in the vehicle networking according to claim 3, wherein: Based on the height of the geometric boundary of the direct line-of-sight area, use geometric relationships to determine the heights of the geometric boundaries of the direct non-line-of-sight area and the reflected non-line-of-sight area respectively.

5. The method for improving spectrum availability in the vehicle networking according to claim 1, characterized in that: The calculation of the interference power specifically includes: Calculate the reflection coefficient and transmission coefficient of vertical polarization, and the reflection coefficient and transmission coefficient of horizontal polarization in the area where each primary user is located respectively; Calculate the interference power of vertical polarization according to the reflection coefficient and transmission coefficient of vertical polarization; Calculate the interference power of horizontal polarization according to the reflection coefficient and transmission coefficient of horizontal polarization.

6. The method for improving spectrum availability in the vehicle networking according to claim 1, wherein: In the road model, there are two traffic flows on the viaduct and one traffic flow under the viaduct, and the distributions of the two traffic flows follow the Poisson distribution.

7. The method for improving spectrum availability in a vehicle-to-everything network according to claim 1, wherein: The antenna of the vehicle terminal includes a transmitting antenna and a receiving antenna, and the signal propagation follows the log-distance path loss model.

8. The method for improving spectrum availability in the vehicle networking according to claim 1, characterized in that: The parameters that affect the interference power include the height of the viaduct, the distance between the viaduct and the high-rise buildings on both sides, and the antenna height of the vehicle terminal.

9. A system for improving spectrum availability in a vehicle-to-everything (V2X) network, characterized in that: The system includes: A model establishment module, used to establish a road model including a viaduct and high-rise buildings on both sides of the viaduct. The vehicle distribution on the viaduct and the ground road under the viaduct is sparse, and each channel can only be accessed by one secondary user at the same time. The secondary user is the vehicle terminal on the ground road under the viaduct, and the primary user is located in the high-rise building. Classify the area where the primary user is located according to the signal reception characteristics; A geometric boundary calculation module, which is used to estimate the geometric boundaries of the regions where primary users of each type are located by taking the positions and distances between the viaduct and high-rise buildings, the viaduct and ground roads, and the antenna positions of vehicle terminals as factors; An interference power calculation module, which is used to calculate the interference power from the secondary user transmitter to the primary user receiver in the regions where primary users of each type are located respectively based on the geometric boundaries by adopting a two-path propagation model; A parameter adjustment module, which is used to adjust the parameters that affect the interference power in the regions where each primary user is located, so that the interference power is within a certain range, so that the spectra of primary users and secondary users in this region can be shared.

10. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the steps of the method for improving spectrum availability in the vehicle-to-everything network according to any one of claims 1 to 8.

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