Transmission method of millimeter wave vehicle network cooperative interference based on transmission blocking

Abstract

The present invention discloses a transmission method for cooperative interference of millimeter wave vehicle network based on transmission blocking, which relates to the field of signal processing technology, including: constructing a V2X network scenario; deploying an array antenna at a communication node in the V2X network scenario, whose communication channel is a millimeter wave channel, modeling the millimeter wave channel, and obtaining a millimeter wave blocking model; using a maximum average power access strategy to obtain a base station connected to a legal receiving vehicle; according to the millimeter wave blocking model, obtaining idle users that meet the first condition, and using a random process to obtain a first idle user set; in the first idle user set, obtaining idle users that meet the second condition, and using a random process to obtain a second idle user set; according to the millimeter wave blocking model, the first idle user set and the second idle user set, obtaining a theoretical expression of the confidentiality performance of the V2X network, and evaluating the confidentiality performance of the V2X network. The present invention can improve the confidentiality performance of the network in a more efficient way.

Description

Technical Field

[0001] The present invention belongs to the technical field of signal processing, and specifically relates to a transmission method for millimeter-wave vehicle network cooperative interference based on transmission blocking. Background Art

[0002] V2X (Vehicle to X) is a key technology for future intelligent transportation systems, which enables communication between vehicles, vehicles and base stations, and base stations. It can obtain a series of traffic information such as real-time road conditions, road information, pedestrian information, etc., thereby improving driving safety, reducing congestion, improving traffic efficiency, and providing in-vehicle entertainment information.

[0003] In the existing technology, due to the high mobility of communication nodes in the V2X network, the node location may change frequently and the network as a whole has a strong time-varying characteristic, so the communication link connection faces the problem of extreme instability; usually, the V2X network is combined with cellular wireless access technology, which can solve the connection stability obstacles in the actual application of vehicle network communication in the past, increase the capacity of the communication channel, and enhance the connection stability of the communication link; in addition, the emergence of millimeter wave technology promotes cellular vehicle network communication into a new stage of development. However, since the C-V2X network still lacks standardized protection protocols or mechanisms, key confidential information transmitted in the network may be maliciously stolen and eavesdropped, and may endanger human life safety due to information leakage.

[0004] Therefore, it is urgent to improve the defects in the existing technology. When designing the C-V2X communication network, communication security should be given the highest priority and attention. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a transmission method for millimeter wave vehicle network cooperative interference based on transmission blocking. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a transmission method for millimeter-wave vehicle network cooperative interference based on transmission blocking, comprising:

[0007] Constructing a V2X network scenario; the communication nodes of the V2X network scenario include a legal receiving vehicle, an eavesdropping vehicle, an idle user, and a base station;

[0008] An array antenna is deployed at a communication node in the V2X network scenario, wherein the communication channel is a millimeter wave channel, and the millimeter wave channel is modeled to obtain a millimeter wave blocking model;

[0009] Using a maximum average power access strategy to acquire a base station connected to the legal receiving vehicle;

[0010] According to the millimeter wave blocking model, the idle users meeting the first condition are acquired, and a first idle user set is obtained by using a random process;

[0011] In the first idle user set, obtaining idle users that meet a second condition, and obtaining a second idle user set using a random process;

[0012] According to the millimeter wave blocking model, the first idle user set and the second idle user set, a theoretical expression of the confidentiality performance of the V2X network is obtained, and the confidentiality performance of the V2X network is evaluated.

[0013] Beneficial effects of the present invention:

[0014] The present invention provides a transmission method for cooperative interference of millimeter-wave vehicle networks based on transmission blocking. The method performs scenario modeling on the millimeter-wave cellular V2X network, including network node location distribution, antenna array model, and millimeter-wave channel. Secondly, considering that the communication process of the present invention is a downlink communication process from a cellular base station to a legally accessed vehicle, the access strategy of the base station is determined, and it is clear which base station the legally accessed vehicle accesses. The physical layer security transmission scheme designed by random geometric analysis is theoretically improved for the security performance of the cellular V2X network, and a theoretical expression is given through theoretical derivation. Among them, the physical layer security technology directly utilizes the random characteristics of the physical channel and does not rely on the complexity of the encryption algorithm. Compared with the traditional key encryption technology, it can improve the confidentiality performance of the network in a more efficient way.

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a flow chart of a transmission method of millimeter wave vehicle network cooperative interference based on transmission blocking provided by an embodiment of the present invention;

[0017] Figure 2 is a schematic diagram of a V2X network scenario provided by an embodiment of the present invention;

[0018] Figure 3 It is a schematic diagram of the change of the confidentiality interruption probability of a typical vehicle with the number of jammers provided by an embodiment of the present invention;

[0019] Figure 4 It is a schematic diagram of a jammer selection scheme provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0021] In the existing technology, the following three types of solutions are usually adopted, namely, theoretical analysis technology of communication performance in V2X network; technology of secure transmission using cooperative interference in planar network; network security technology based on key encryption. Among them, considering that the theoretical research and analysis of vehicle communication needs to be based on the analysis framework of random geometry, researchers have proposed some V2X network performance analysis technologies based on random geometry. In addition, some researchers modeled the spatial position of communication nodes in the vehicle network as a Cox process driven by the same Poisson line process, and then gave a theoretical formula for evaluating the coverage performance and confidentiality performance of the V2X network.

[0022] The above research mainly focuses on the invention of theoretical analysis methods, and has not yet involved the design of secure transmission schemes in V2X networks. The main reasons are: First, the unique location characteristics of vehicles bring computational complexity to theoretical analysis; vehicles are always distributed along the streets, and the common two-dimensional Poisson point process is no longer applicable to the modeling of node location distribution in V2X networks that are restricted by roads, causing researchers to focus on the performance analysis of V2X networks; second, the second type of related invention technology is mainly cooperative interference transmission technology applicable to ordinary planar networks. The core of this type of technology is to design an interference node screening scheme that meets the needs, and the needs are mainly the network's requirements for confidentiality performance; third, the network layer security technology based on key encryption protects confidential information based on the complexity of the confidentiality algorithm. The longer the key and the more complex the encryption algorithm, the better the confidentiality of the information, which makes the process complicated.

[0023] In summary, existing technologies have limited research on the issue of secure transmission in millimeter wave V2X networks. First of all, since the communication involving vehicles in the network is very sensitive to communication delays, especially the extremely high delay requirements for downlink transmission, traditional network security key encryption technology is no longer the best choice for V2X networks. In addition, the research on physical layer security technology in existing V2X networks mainly focuses on the security performance analysis of the entire network when using basic physical layer security technology or without any secure transmission design. However, the communication security in the actual Internet of Vehicles indirectly determines the personal safety of people in the network to a certain extent, so it is very important to study and design an effective secure transmission solution in the V2X network.

[0024] The existing technology has limited consideration for network communication reliability when designing cooperative interference cooperation node selection strategies. The improvement of transmission security performance is achieved at the expense of the reliability of target link transmission. In V2X networks, due to the high mobility of nodes, the probability of connection interruption is higher than other static networks. Therefore, it is not advisable to endlessly exchange connection performance for the improvement of confidentiality performance, and it may even lead to an extreme deterioration of the receiving signal-to-noise ratio of the target transmission link.

[0025] In view of this, the present invention uses physical layer cooperative interference technology to propose a transmission method for millimeter wave vehicle network cooperative interference based on transmission blocking, so as to solve the potential security threats in millimeter wave cellular V2X network from the perspective of physical layer. In addition, the present invention also uses random geometric analysis method to analyze and solve the indicators representing the security transmission performance of the communication system, the theoretical expressions of confidentiality interruption probability and confidentiality throughput, and thus can achieve effective and reasonable estimation of system security performance.

[0026] See also Figure 1 and Figure 2 As shown, Figure 1 is a flow chart of a transmission method for millimeter-wave vehicle network cooperative interference based on transmission blocking provided by an embodiment of the present invention. Figure 2 is a schematic diagram of a V2X network scenario provided by an embodiment of the present invention; a transmission method of millimeter wave vehicle network cooperative interference based on transmission blocking provided by the present invention includes:

[0027] S101, constructing a V2X network scenario; the communication nodes of the V2X network scenario include a legal receiving vehicle, an eavesdropping vehicle, an idle user, and a base station;

[0028] S102, deploying an array antenna at a communication node in a V2X network scenario, where the communication channel is a millimeter wave channel, modeling the millimeter wave channel, and obtaining a millimeter wave blocking model;

[0029] S103, using the maximum average power access strategy to obtain a base station connected to a legal receiving vehicle;

[0030] S104. Obtain idle users that meet the first condition according to the millimeter wave blocking model, and obtain a first idle user set using a random process;

[0031] S105, obtaining idle users meeting a second condition from the first idle user set, and obtaining a second idle user set using a random process;

[0032] S106. According to the millimeter wave blocking model, the first idle user set, and the second idle user set, a theoretical expression of the confidentiality performance of the V2X network is obtained, and the confidentiality performance of the V2X network is evaluated.

[0033] For more details, please see Figure 1As shown, the transmission method of millimeter-wave vehicle network cooperative interference based on transmission blocking provided in this embodiment firstly models the scenario of the millimeter-wave cellular V2X network, including the network node location distribution, antenna array model, and millimeter-wave channel; secondly, considering that the communication process of the present invention is a downlink communication process from a cellular base station to a legally accessed vehicle, the access strategy of the base station is determined, and it is clear which base station the legally accessed vehicle accesses, and the physical layer security transmission scheme designed by random geometric analysis is theoretically improved for the security performance of the cellular V2X network, and a theoretical expression is given through theoretical derivation; wherein, the physical layer security technology directly utilizes the random characteristics of the physical channel and does not rely on the complexity of the encryption algorithm. Compared with the traditional key encryption technology, it can improve the confidentiality performance of the network in a more efficient way.

[0034] In an optional embodiment of the present invention, building a V2X network scenario includes:

[0035] Obtain the location of the legal receiving vehicle and use it as the origin;

[0036] Use density λ L Line process Φ L Modeling roads;

[0037] The density is μ e One-dimensional point process For L k The location distribution of eavesdropping vehicles on the road is modeled; where e is the specific location of the eavesdropping vehicle,

[0038] Use density λ B The point process Φ B Model the location of the base station; where b is the location of the base station, b∈Φ B ;

[0039] Use density λ U The point process Φ U Model the location of idle users; where u is the location of idle users, u∈Φ U .

[0040] Specifically, in this embodiment, the constructed V2X network scenario includes a single legal receiving vehicle, multiple base stations, and multiple eavesdropping vehicles. The main communication process is: when an emergency occurs, the base station transmits a confidential signal to the legal receiving vehicle through a downlink. At the same time, the surrounding eavesdropping vehicles will passively eavesdrop on the confidential signal, and the idle users in the network act as potential jammers to interfere with the signal. In the process of constructing the V2X network scenario, the legal receiving vehicles, eavesdropping vehicles, and idle users whose positions are restricted by the road are first described using the Poisson line process to describe the randomly distributed positions of the road, and then the one-dimensional Poisson point process with the same density is used to describe the legal receiving vehicles, eavesdropping vehicles, and idle users; it can be understood that the position of the legal receiving vehicle is obtained and used as the origin; the density is λ L Line process Φ L Model the road; use density μ e One-dimensional point process For L k The location distribution of the eavesdropping vehicle on the road is modeled; wherein e is the specific location of the eavesdropping vehicle, Use density λ B The point process Φ B Model the location of the base station; where b is the location of the base station, b∈Φ B ; Use density λ U The point process Φ U Model the position of the idle user; where u is the position of the idle user, u∈Φ U ; In this way, the constructed V2X network scenario facilitates the formulation and theoretical analysis of interference node selection strategies.

[0041] In an optional embodiment of the present invention, the gain of the array antenna is:

[0042]

[0043] Among them, t is the signal transmitting end, r is the signal receiving end, M is the main lobe gain, m is the side lobe gain, θ is the main lobe width, is the probability that the signal is transmitted by the main lobe at the transmitter and received by the main lobe at the receiver.

[0044] Specifically, in this embodiment, an array antenna is deployed at a communication node in a V2X network scenario, and a sector model is used to approximate the gain effect generated by the antenna array. The gain of the array antenna obtained is:

[0045]

[0046] Among them, t is the signal transmitting end, r is the signal receiving end, M is the main lobe gain, m is the side lobe gain, θ is the main lobe width, is the probability that the signal is transmitted by the main lobe at the transmitter and received by the main lobe at the receiver.

[0047] It should be noted that each base station can adjust the direction of its main lobe according to the position of the legal receiving vehicle to achieve perfect alignment with the receiving main lobe of the legal receiving vehicle; in addition, all communication nodes transmit with the same power P t Transmit signal.

[0048] In an optional embodiment of the present invention, according to the millimeter wave blocking model, the blocking state of the communication link between other communication nodes at different distances from the signal transmitting end is obtained;

[0049] The communication links include LoS links and NLoS links;

[0050] Among them, the probability that the communication link with a distance d from the signal transmitter is a LoS link is p L (d), its expression is:

[0051]

[0052] Among them, p L is a constant based on empirical values, p L =0.2, D is the radius of the LoS sphere;

[0053] The probability that a communication link with a distance d from the signal transmitter is an NLoS link is p N (d), its expression is:

[0054] p N (d) = 1-p L (d).

[0055] Specifically, in this embodiment, considering that the communication channel of the array antenna is a millimeter wave channel, which is easily affected by blocking, it is considered that there are two situations of line-of-sight propagation (LoS) and non-line-of-sight propagation (NLoS) between communication nodes; wherein the constructed millimeter wave blocking model is a blocking ball model, which is used to describe the blocking state of the communication link between other communication nodes at different distances from the signal transmitting end, and the probability that the communication link with a distance d from the signal transmitting end is a LoS link is p L (d), its expression is:

[0056]

[0057] Among them, p L is a constant based on empirical values, p L =0.2, D is the radius of the LoS sphere;

[0058] The probability that a communication link with a distance d from the signal transmitter is an NLoS link is p N (d), its expression is:

[0059] p N (d) = 1-p L (d).

[0060] It should be noted that, for simplicity, all parameters or variables related to the blocking state are identified by subscript i∈{L,N}, where L and N identify the LoS link and the NLoS link, respectively.

[0061] In an optional embodiment of the present invention, the signal power received by the communication node at a distance d from the signal transmitting end t is:

[0062]

[0063] Among them, P t is the transmitting power, h i is the small-scale fading of the channel, is the propagation loss of the signal during propagation, i is the blocking state of the link, α i is the loss index of the communication link associated with the blocking state.

[0064] Specifically, in this embodiment, considering that the millimeter wave is affected by the blocking mainly due to small-scale fading and path propagation loss; in this embodiment, Nakagami-m fading is used to describe the fading environment experienced by the millimeter wave channel, and an independent and identically distributed random variable h is used to describe the fading environment experienced by the millimeter wave channel. i ~Γ(Ni,1 / N i ) represents the channel gain; due to the millimeter wave blocking effect, the propagation loss generated by the signal during propagation is expressed by the path loss function Indicates that, where α i is the loss index of the communication link associated with the blocking state, is the path loss intercept, and the signal power received by the communication node at a distance d from the signal transmitter t is obtained as

[0065] In an optional embodiment of the present invention, the base station connected to the legal receiving vehicle is:

[0066]

[0067] Among them, P t is the transmission power, G b,o To obtain the antenna gain, is the path loss, b is the location of the base station, and o is the location of the legal receiving vehicle.

[0068] Specifically, in this embodiment, in order to ensure that the signal quality received by the legal receiving vehicle is the best, a maximum average power access strategy is selected to select the base station to which the legal receiving vehicle is connected.

[0069] In an optional embodiment of the present invention, according to the blocking state of the communication link between the base station and the legal receiving vehicle, the base station is set to a corresponding LoS link base station and a corresponding NLoS link base station, that is, the point process Φ B include and

[0070] Get the probability A that the legal receiving vehicle receives the corresponding NLoS link base station N , whose expression is:

[0071]

[0072] Where χ is the antenna gain, χ∈{M 2 ,Mm,m 2}, M is the main lobe gain, m is the side lobe gain, σ is the signal strength, C L is the LoS link loss intercept, α L is the LoS link loss index;

[0073] Get the probability A that the legal receiving vehicle receives the corresponding LoS link base station L , whose expression is:

[0074] A L =1-A N ;

[0075] Get the probability density of the signal strength σ received by the legal receiving vehicle from the corresponding LoS link base station Its expression is:

[0076]

[0077] Obtain the probability density of the signal strength σ received by the legal receiving vehicle from the corresponding NLoS link base station Its expression is:

[0078]

[0079] p N is the probability that the link is in NLoS state when the link length d≤D, C N is the NLoS link loss intercept, α N is the NLoS link loss index.

[0080] Specifically, in this embodiment, according to the link blocking state between each base station and the legal receiving vehicle, the base station is divided into two types of base stations with LoS links and NLoS links between the base station and the legal receiving vehicle, and then the point process Φ B Divide into two sub-processes and Right now After clarifying the access strategy of the base station, in order to obtain the probability of a legal receiving vehicle accessing each base station, it is necessary to first calculate the probability of a legal receiving vehicle accessing the LoS base station and the NLoS base station respectively.

[0081] In an optional embodiment of the present invention, the first condition is: an idle user whose communication link with the legal receiving vehicle is an NLoS link.

[0082] Specifically, in this embodiment, an idle user that meets the first condition is determined according to the screening principle. Considering that the information of the eavesdropped vehicle is generally unknown in reality, when selecting nodes that can be used as collaborative jammers, it is more reasonable and more in line with the actual situation to select nodes that may have the smallest possible interference intensity to the legitimate receiving vehicle nodes from the perspective of the legitimate receiving vehicle nodes rather than selecting nodes that can produce the maximum interference intensity to the eavesdropped vehicle from the perspective of the legitimate receiving vehicle nodes. From the perspective of the propagation characteristics of millimeter waves, signals propagated through NLoS links will suffer from greater intensity loss; based on this, it is necessary to select idle user nodes whose communication links with the legitimate receiving vehicles are NLoS.

[0083] The idle users meeting the first condition obtained above and the first idle user set are obtained. The location distribution of the first idle user set is obtained using the following method, specifically,

[0084] The NLoS sphere with radius D is used as the boundary, and the idle users within the circle have a density of p. N λ B Two-dimensional Poisson point process The idle users outside the circle have a density of λ B Poisson point process Φ B,O ,Right now

[0085] In an optional embodiment of the present invention, the second condition is: the idle user transmits a signal whose strength to the legal receiving vehicle is less than the strength threshold τ, that is:

[0086]

[0087] Among them, h N is the small-scale fading of the NLoS link channel.

[0088] Specifically, in this embodiment, in the first idle user set, the second idle user set is screened out using the second condition; it can be understood that in addition to requiring the link between the legal receiving vehicle and the legal receiving vehicle to be NLoS, it is also necessary to limit the signal strength that these potential interference nodes may generate to the legal receiving vehicle; the maximum interference strength that the legal receiving vehicle can withstand is set to τ, then the second screening condition is: the signal strength transmitted by the node that can be selected as the interference node to the legal receiving vehicle must be less than the strength threshold τ, then the second condition is: the signal strength transmitted by the node that can be selected as the interference node to the legal receiving vehicle must be less than the strength threshold τ, that is:

[0089]

[0090] From a physical point of view, the second condition that can be satisfied by a cooperative interference node is:

[0091]

[0092] set up

[0093] in, is the power limit radius, and the final screening result is expressed as in is a circle with o as the center, The complementary space of the circle with radius Φ; the position distribution of the interference nodes finally selected is Φ J .

[0094] In an optional embodiment of the present invention, the theoretical expression of the confidentiality performance of the V2X network is:

[0095]

[0096] where β e is the signal-to-interference ratio threshold that causes a confidentiality interruption event, is the restricted zone radius in the interference node selection, τ is the maximum interference power intensity that the legal receiving vehicle can withstand, and is a threshold value for the receiving power. When the signal-to-interference ratio at any eavesdropping node exceeds the threshold, a confidentiality interruption event is considered to have occurred.

[0097] Specifically, in this embodiment, in order to analyze the security performance of the cellular V2X network under the designed cooperative interference security transmission scheme, it is necessary to obtain a theoretical expression of the confidentiality performance of the V2X network:

[0098]

[0099] Among them, SIR b,e represents the signal-to-interference ratio of the eavesdropping node at position e;

[0100] According to the millimeter wave blocking model, Φ E Break it down into three parts:

[0101]

[0102] Since the signal-to-interference ratio can be expanded as:

[0103]

[0104] Substituting it in and solving for the expectation of the random variable we get:

[0105] The Laplace transform is:

[0106]

[0107]

[0108]

[0109]

[0110] According to the LoS sphere radius D and power limit radius A1 and A2 have different values:

[0111]

[0112]

[0113] in,

[0114]

[0115] Through the above process, the confidentiality performance of the V2X network can be evaluated.

[0116] In an optional embodiment of the present invention, the transmit power and the shared antenna parameters are set to P t =30dBm, the main lobe and side lobe gains are set to M = 10dB and m = -10dB respectively, and the corresponding main lobe width is The blocking related parameters are set as follows: α L =2, α N =2.92, N L =3, N N =2, β L =61.4, β N =72; the radius of the LoS sphere is set to D=100m.

[0117] See also Figure 3 and Figure 4 As shown, Figure 3is a schematic diagram of the change in the confidentiality interruption probability of a typical vehicle with the number of jammers provided by an embodiment of the present invention, Figure 4 is a schematic diagram of a jammer selection scheme provided by an embodiment of the present invention; Figure 2 It can be seen that as more jammers participate in the transmission process, the probability of confidentiality interruption decreases significantly. The impact of eavesdropping can be reduced by using relatively few jammers compared to the number of eavesdroppers, as shown by the line with triangles. In addition, it is not difficult to find that the narrower the beam of the jammer, the less likely the eavesdropper is to be covered, resulting in a smaller inhibitory effect of the jammer on the eavesdropper. Figure 3 It can be seen that the RPJ strategy provided in this embodiment is compared with the existing SCJ solution and the "no choice" strategy that does not make any choice. The overall performance of the three solutions is characterized by confidentiality throughput. The optimal power limit radius that maximizes confidentiality throughput Under the above conditions, the RPJ scheme proposed in this embodiment is always better than the SCJ scheme. Both RPJ and SCJ are better than the "no choice" scheme. The RPJ scheme will mitigate the impact of interference on legitimate receivers because RPJ imposes strict restrictions on the power of possible interference signals received by legitimate receivers. In addition, the figure also shows that as the number of eavesdroppers increases, more jammers are needed to suppress interception.

[0118] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the article or device including the elements. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The orientation or position relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0119] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0120] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A transmission method for millimeter wave vehicle network cooperative interference based on transmission blocking, characterized in that: include: Build V2X network scenarios; The communication nodes of the V2X network scenario include legal receiving vehicles, eavesdropping vehicles, idle users and base stations; An array antenna is deployed at a communication node in the V2X network scenario, and its communication channel is a millimeter wave channel. The millimeter wave channel is modeled to obtain a millimeter wave blocking model; the millimeter wave blocking model is a blocking ball model, and according to the millimeter wave blocking model, a blocking state of a communication link between other communication nodes at different distances from a signal transmitting end is obtained; the communication link includes a LoS link and an NLoS link, L and N respectively identify the LoS link and the NLoS link, i∈{L,N}; Among them, the probability that the communication link with a distance d from the signal transmitter is a LoS link is p L (d), its expression is: Among them, p L is a constant based on empirical values, D is the radius of the LoS sphere; The probability that a communication link with a distance d from the signal transmitter is an NLoS link is p N (d), its expression is: p N (d)=1-p L (d); Through independent and identically distributed random variables h i ~Γ(N i ,1 / N i ) represents the channel gain, and the signal power received by the communication node at a distance d from the signal transmitter t is: Among them, P t is the transmitting power, h i is the small-scale fading of the channel, is the propagation loss of the signal during propagation, i is the blocking state of the link, α i is the loss index of the communication link associated with the blocking state; Due to the millimeter wave blocking effect, the propagation loss of the signal during propagation is expressed by the path loss function. Indicates that, α i is the loss index of the communication link associated with the blocking state, is the path loss intercept, and the signal power received by the communication node at a distance d from the signal transmitter t is obtained as Use the maximum average power access strategy to obtain the base station connected to the legal receiving vehicle; the base station connected to the legal receiving vehicle is: Among them, P t is the transmission power, G b,o To obtain the antenna gain, is the path loss, b is the location of the base station, o is the location of the legal receiving vehicle, and h i is the small-scale fading of the channel, Φ B It is a point process; According to the millimeter wave blocking model, the idle users meeting the first condition are obtained, and a first idle user set is obtained by using a random process; the first condition is: the idle users whose communication link with the legal receiving vehicle is an NLoS link; according to the idle users meeting the first condition and the first idle user set, the position distribution of the first idle user set is obtained, specifically: The NLoS sphere with radius D is used as the boundary, and the idle users within the circle have a density of p. N λ B Two-dimensional Poisson point process The idle users outside the circle have a density of λ B Poisson point process Φ B,O ,Right now In the first idle user set, an idle user meeting the second condition is obtained, and a second idle user set is obtained using a random process; the second condition is that the idle user is an idle user whose signal strength transmitted to the legal receiving vehicle is less than the strength threshold τ, that is: Among them, h N is the small-scale fading of the NLoS link channel, P t is the transmission power, C N is the NLoS link loss intercept; In the first idle user set, the second idle user set is selected by using the second condition, specifically: the maximum interference intensity that the legal receiving vehicle can bear is set to τ, that is, the intensity threshold, and the second condition is that the signal intensity transmitted by the node that can be selected as the interference node to the legal receiving vehicle is less than the intensity threshold τ, that is: The conditions that must be met to be a cooperative interference node are: set up in, is the power limit radius, and the screening result is expressed as is a circle with o as the center, The complementary space of the circle with radius Φ, the position distribution of the selected interference nodes is Φ J ; According to the millimeter wave blocking model, the first idle user set and the second idle user set, a theoretical expression of the confidentiality performance of the V2X network is obtained, and the confidentiality performance of the V2X network is evaluated; the theoretical expression of the confidentiality performance of the V2X network is: Among them, β e is the signal-to-interference ratio threshold that causes a confidentiality interruption event, P t is the transmission power, C N is the NLoS link loss intercept, α N is the NLoS link loss index.

2. The transmission method of millimeter wave vehicle network cooperative interference based on transmission blocking according to claim 1 is characterized in that: The V2X network construction scenario includes: Obtaining the position of the legally received vehicle and using it as the origin; Use density λ L Line process Φ L Modeling roads; The density is μ e One-dimensional point process For L k The location distribution of the eavesdropping vehicle on the road is modeled; wherein e is the specific location of the eavesdropping vehicle, Use density λ B The point process Φ B Model the location of the base station; where b is the location of the base station, b∈Φ B ; Use density λ U The point process Φ U Model the position of the idle user; where u is the position of the idle user, u∈Φ U .

3. The transmission method of millimeter wave vehicle network cooperative interference based on transmission blocking according to claim 1 is characterized in that: The gain of the array antenna is: Among them, t is the signal transmitting end, r is the signal receiving end, M is the main lobe gain, m is the side lobe gain, θ M is the main lobe width, is the probability that the signal is transmitted by the main lobe at the transmitter and received by the main lobe at the receiver.

4. The transmission method of millimeter wave vehicle network cooperative interference based on transmission blocking according to claim 1 is characterized in that: The signal power received by the communication node at a distance d from the signal transmitter t is: Among them, P t is the transmitting power, h i is the small-scale fading of the channel, is the propagation loss of the signal during propagation, i is the blocking state of the link, α i is the loss index of the communication link associated with the blocking state.

5. The transmission method of millimeter wave vehicle network cooperative interference based on transmission blocking according to claim 1 is characterized in that: According to the communication link blocking state between the base station and the legal receiving vehicle, the base station is set to the corresponding LoS link base station and the corresponding NLoS link base station, that is, the point process Φ B include and Obtain the probability A that the legal receiving vehicle receives the corresponding NLoS link base station N , whose expression is: Where χ is the antenna gain, χ∈{M 2 ,Mm,m 2 }, M is the main lobe gain, m is the side lobe gain, σ is the signal strength, C L is the LoS link loss intercept, α L is the LoS link loss index, D is the radius of the LoS sphere; Obtain the probability A that the legal receiving vehicle receives the corresponding LoS link base station L , whose expression is: A L =1-A N ; Obtain the probability density of the signal strength σ received by the legal receiving vehicle from the corresponding LoS link base station Its expression is: Obtain the probability density of the signal strength σ received by the legal receiving vehicle from the corresponding NLoS link base station Its expression is: Among them, p N is the probability that the link is in NLoS state when the link length d≤D, C N is the NLoS link loss intercept, α N is the NLoS link loss index, p L is a constant based on empirical values.

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