阅读说明：本技术 一种随机波束切换的毫米波物理层密钥生成方法及系统 (Millimeter wave physical layer key generation method and system for random beam switching ) 是由 俱莹 邹国学 白皓文 裴庆祺 于 2021-07-14 设计创作，主要内容包括：本发明属于无线物理层安全通信技术领域,公开了一种随机波束切换的毫米波物理层密钥生成方法及系统,所述随机波束切换的毫米波物理层密钥生成方法包括：通信双方A和B进行初始信道探测,获得毫米波信道的状态信息；进行随机波束切换的物理层密钥生成；进行物理层密钥组合。本发明方法利用毫米波信道的稀疏性,将毫米波信道稀疏性响应的坐标作为随机源；通过随机波束切换的方法,在保证密钥随机性的前提下,实现了高速率的物理层密钥生成。理论分析和仿真结果表明,本发明方法的密钥生成速率突破了信道相关时间的限制；密钥协商前的密钥之间具有较高的一致性,节省了密钥协商和隐私放大过程的开销,且具备对抗多天线窃听者的能力。(The invention belongs to the technical field of wireless physical layer secure communication, and discloses a millimeter wave physical layer key generation method and system for random beam switching, wherein the millimeter wave physical layer key generation method for random beam switching comprises the following steps: the communication parties A and B carry out initial channel detection to obtain state information of a millimeter wave channel; generating a physical layer key for random beam switching; physical layer key combination is performed. The method uses the sparsity of the millimeter wave channel and takes the coordinates of the sparse response of the millimeter wave channel as a random source; by the random beam switching method, the high-speed physical layer key generation is realized on the premise of ensuring the randomness of the key. Theoretical analysis and simulation results show that the key generation rate of the method breaks through the limit of the relevant time of the channel; the keys before key agreement have higher consistency, the expenses of the key agreement and the privacy amplification process are saved, and the method has the capability of resisting a multi-antenna eavesdropper.)

1. A millimeter wave physical layer key generation method for random beam switching is characterized by comprising the following steps:

the communication parties A and B carry out initial channel detection to obtain state information of a millimeter wave channel;

generating a physical layer key for random beam switching;

physical layer key combination is performed.

2. The method for generating random beam-switched millimeter wave physical layer keys according to claim 1, wherein the initial channel sounding comprises:

(1) before generating a physical layer key, a communication party A and a communication party B agree to uniformly quantize the azimuth angle of a millimeter wave beam to N according to the size of a sine value, namely, each angle satisfies the following formula:

wherein θ is the azimuth of the beam;

(2) two communication parties A and B transmit orthogonal reference signals X to each other in a time division duplex mode in a static environment correlation time_ABAnd X_BA(ii) a At a certain time, the communication party A transmits a reference signal X to the communication party B_ABPassing through t_ABAfter the time, the communication partner B receives the signal Y_B(ii) a The communication party B sends the reference signal X to the communication party A after the processing time delay of delta t time_BACommunication party A passes time t_BAAfter receiving signal Y_A(ii) a Two communication parties carry out channel bidirectional detection onceThe total time of the two-way detection satisfies t_AB+Δt+t_BA≤T_c(ii) a Wherein T is_cIs the radio channel correlation time.

3. The millimeter wave physical layer key generation method for random beam switching as claimed in claim 1, wherein the physical layer key generation for random beam switching comprises:

(1) both communication parties A and B receive signal Y_AAnd Y_BEstimating a millimeter wave channel, acquiring L limited space distinguishable scattering paths meeting the millimeter wave communication requirement, and acquiring information of L pairs of corresponding sparsity response coordinates;

when the number of antennas is different between the transmitter and the receiver, there may be three kinds of correspondence between the beam departure angle and the arrival angle:

one-to-many: the number of the antennas of the transmitting party is less than that of the antennas of the receiving party;

two-to-one: the number of the antennas of the sender is more than that of the antennas of the receiver;

③ one-to-one: the number of the antennas of the sender is equal to that of the antennas of the receiver;

for the three cases, the corresponding situation between the arrival angle and the departure angle of the beam between the sender and the receiver can be obtained by combining the channel estimation result;

(2) using the millimeter wave channel sparsity response coordinates obtained in the step (1) as a random source for generating a physical layer key by both communication parties A and B, and generating a first group of physical layer keys in channel correlation time in a static environment;

(3) a communication party A (B) randomly generates an integer zeta ∈ {1,2, …, L }, wherein L is the number of millimeter wave channel space-resolvable scattering paths between the communication parties A (B), namely the number of sparsity response coordinates obtained in the step (1); the random integer zeta is used for selecting the number of beams activated by the communication party of the secondary channel detection as the sending party;

(4) according to the random selection result of the step (3), the communication party A (B) randomly generates an integerFor selecting a combination of active beams; based on the generation of random integers ζ and δ, the beam combination for the transmitting end to switch is 2 in total^L-1 species;

(5) and (B) as a transmitting end, activating corresponding beams according to the integers zeta and delta randomly selected in the steps (3) and (4), and transmitting the orthogonal reference signal X on the activated beams_AB(X_BA) Generating a sending end key according to the beam selection result and the corresponding relation between the arrival angle and the departure angle of the beam in the step (1);

(6) the communication party B (A) as the receiving end receives the signal Y_B(Y_A) Estimating a millimeter wave channel, and extracting a millimeter wave channel sparsity response coordinate after beam selection as a random source;

(7) the communication party B (A) is used as a receiving end, and generates a receiving end physical layer key according to the channel estimation result in the step (6) and by combining the channel initial detection result in the step (1) and the corresponding relation between the beam arrival angle and the beam departure angle;

(8) and (4) the two communication parties can repeatedly execute the steps (3) to (7) in the relevant time of the channel, randomly switch the beam combination to perform channel detection, and generate more keys in the relevant time under the condition of ensuring the randomness of the keys.

4. The millimeter wave physical layer key generation method for random beam switching according to claim 3, wherein in step (1) and step (6), the millimeter wave channel estimation process comprises:

step (1) receiving a reference signal Y_AAnd Y_BThe following were used:

Y_A＝H_BAX_BA+Q_BA；

Y_B＝H_ABX_AB+Q_AB；

step (6) receiving a reference signal Y_AAnd Y_BThe following were used:

Y_A＝H_BAX_BAV_s+Q_BA；

Y_B＝H_ABX_ABV_s+Q_AB；

wherein H_ABAnd H_BARespectively representing a channel matrix of a communication party A to a communication party B and a channel matrix of the communication party B to the communication party A; v_sA pre-coding matrix representing a transmitting side, which is used for selecting an active beam combination; q_ABAnd Q_BAIs complex Gaussian noise which is independently and equally distributed;

because two communication parties A and B carry out bidirectional channel detection in the relevant time of the channel, two channel matrixes satisfy H according to the reciprocity principle of a wireless channel_AB＝H_BA ^H；

Adopting a DFT codebook to perform precoding reception on a received signal so as to obtain sparsity information of a millimeter wave channel; wherein the obtained channel matrix H of millimeter wave_ABEquivalent sparse channel matrixThe following were used:

wherein A is_B,DAnd A_A,DDFT codebooks, X, representing correspondent B and correspondent A, respectively_ABFor quadrature reference signals, Q_ABIn order to be a complex noise matrix,represents a millimeter wave sparse channel matrix and can equivalently represent a millimeter wave channel H_AB：

The channel millimeter wave channel established based on the ray cluster theory is as follows:

wherein, L represents the number of multipath, namely the number of ray clusters; alpha is alpha_lRepresents the channel complex gain of the l path, i.e., the l ray cluster, and satisfy the requirement ofθ_A,lAnd phi_B,lThe arrival angle and the departure angle, a (theta), corresponding to the ith path_A,l) And a (phi)_B,l) Respectively representing the arrival angles of the receiving ends as theta_A,lAnd a departure angle from the transmitting end of phi_B,lULA array response vector of, N_t＝N_AAnd N_r＝N_BRespectively, the number of antennas of the transmitting side and the receiving side, where a (theta)_A,l) And a (phi)_B,l) Expressed as:

the distance d of the uniform linear array element antenna is equal to lambda/2, and lambda is the wavelength of a transmission signal.

5. The millimeter wave physical layer key generation method for random beam switching according to claim 3, wherein in the step (2), acquiring sparsity response coordinates in the millimeter wave sparsity channel as a random source for generating the physical layer key, comprises:

obtaining a virtual channel matrixSparsity response information that may exist in the beam angle-of-arrival direction:

a communication party B as a receiving end obtains a sparsity response coordinate set J and a corresponding channel response amplitude set V which may exist in the direction of the arrival angle of the beam;

the communication party B as the receiving end acquires sparse response information, and the sparse response information comprises the following steps:

the communication party B sets L to 0, that is, initializes the number of spatially resolved scattering paths, and extracts the current maximum gain beam information:

the communication party B executes the step of extracting the current maximum gain beam information and judges the current maximum gain beam information V (i)_max) Whether the condition 1 is met or not, if so, executing the step corresponding to the condition 1; after the step of extracting the current maximum gain beam information is executed, the step of extracting the current maximum gain beam information is executed in a circulating mode again until V (i)_max) Until condition 2 is satisfied;

condition 1: if V (i) is satisfied_max) If epsilon is a channel path gain critical value, the wave beam in the direction meets the millimeter wave communication requirement, namely sparse response exists; extracting sparsity response information corresponding to the beam, updating a channel response amplitude set V, and deleting the current best beam information to estimate other beam information, wherein the sparsity response information comprises:

G(j)＝V(i_max)；

V(i_max)＝0；

L＝L+1；

condition 2: if V (i)_max) If the epsilon is less than epsilon, the residual path information does not meet the requirement of millimeter wave channel gain, so the channel estimation process is finished;

V(i_max) When the condition 2 is satisfied, the channel estimation is finished, the receiving party obtains the quantity L of the space distinguishable scattering paths between the two communication parties,for the set of virtual channel response impulse coordinates corresponding to the beam angle-of-arrival in the channel estimation result,a coordinate set corresponding to the beam departure angle; g is the set of channel gains for each spatially resolved path.

6. The method for generating a millimeter wave physical layer key for random beam switching according to claim 3, wherein in the step (2), a gray code table is used as a key lookup table to complete mapping between coordinates and keys; wherein the key mapping step comprises:

determining the sequence number of the sparse response coordinate in the virtual channel matrix, wherein the sequence number arrangement method is that k is (x-1) N + y-1, wherein k is the sequence number corresponding to the sparse response coordinate (x, y), x belongs to {1,2, …, N }, and y belongs to {1,2, …, N }; looking up a gray code sequence corresponding to the decimal number k in an I-bit gray code table as a key sequence, whereinWhen the pair between the arrival angle and departure angle of the beam obtained in step (1)The correspondence exists in the case of "many-to-one" or "one-to-many", i.e., the sparse response coordinate set or a subset thereof exists in the form:

{(x₁,y),...,(x_n,y)}；

{(x,y₁),...,(x,y_n)}；

dividing a plurality of angles into a group, mapping the angles into the same coordinate value, namely when one or more of the angles are activated in the group of beams, generating the same physical layer key;

the two communication parties A and B obtain a first group of keys k in the relevant time of the channel by using the key mapping method to complete the mapping between the sparse response coordinate set obtained in the step (1) and the physical layer key sequence_A(B)，0。

7. The millimeter wave physical layer key generation method for random beam switching according to claim 1, wherein the physical layer key combination includes that the two communication parties a and B perform physical layer key generation for random beam switching for multiple times within a relevant time, multiple groups of keys are obtained through random beam switching, and the keys are combined in time sequence to obtain the millimeter wave physical layer key for random beam switching, including:

based on the assumption that the channel state is unchanged in the channel correlation time, if the millimeter wave physical layer key generation for random beam switching is performed n times, the keys obtained by the two communication parties a (b) in the channel correlation time are:

wherein k is_A(B),iAndi belongs to {1,2, …, n } is a physical layer key generated by the sending and receiving of the ith time of a legal communication party A (B); k_A(B),τRepresenting the physical layer key generated during the channel correlation time.

8. A millimeter wave physical layer key generation system for random beam switching, which implements the millimeter wave physical layer key generation method for random beam switching according to any one of claims 1 to 7, wherein the millimeter wave physical layer key generation system for random beam switching comprises:

the channel detection module is used for carrying out initial channel detection on the communication parties A and B to obtain state information of the millimeter wave channel;

the key generation module is used for generating a physical layer key for random beam switching;

and the key combination module is used for carrying out physical layer key combination to obtain a millimeter wave physical layer key switched by random beams.

9. A computer device, characterized in that the computer device comprises a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to carry out the steps of:

the communication parties A and B carry out initial channel detection to obtain state information of a millimeter wave channel; generating a physical layer key for random beam switching; and combining physical layer keys, namely, performing random beam switching multiple times by the two communication parties A and B in related time to generate a physical layer key, obtaining multiple groups of keys through random beam switching, and combining the keys according to a time sequence to obtain a millimeter wave physical layer key switched by random beams.

10. An information data processing terminal characterized by being used for a millimeter wave physical layer key generation system that realizes the random beam switching according to claim 8.

Technical Field

The invention belongs to the technical field of wireless physical layer secure communication, and particularly relates to a millimeter wave physical layer key generation method and system for random beam switching.

Background

At present, the development of wireless communication technology is changing day by day, and the business service of wireless communication network has changed greatly with the rapid development of the industries such as internet of things, smart cities and the like. The ever increasing number of users and data volume has led to an increasing shortage of spectrum resources, and the security of wireless communications is becoming increasingly important due to the continuously abundant information types.

In a conventional wireless secure communication scheme, encryption and decryption technologies and communication protocols are the main ways to implement secure communication. However, with the rapid development of communication technology and computer technology, conventional secure communication mechanisms may face a number of challenges in new communication scenarios or technologies. For example, ultra-low latency requirements in a specific communication scenario cannot be met, distribution and management of keys among heterogeneous internet of things devices are difficult, an existing encryption algorithm is cracked by emerging computing devices, and the like.

Unlike conventional key exchange mechanisms, physical layer key generation techniques exploit the time-varying nature and reciprocity of wireless channels. The method can realize lightweight encryption and decryption without a third party participating in the management and distribution of the key and depending on the complexity of the algorithm, has the potential of realizing information theory safety, and is one of the extremely important development directions in the field of safe communication.

However, most of current research schemes for generating physical layer keys are focused on the microwave frequency band below 6GHz, and cannot be applied to communication systems in the millimeter wave frequency band. In addition, the key generation rate of the conventional scheme is limited by a static environment, in which the channel changes slowly, the channel correlation time is long, and the key generation rate is low, so that the encryption requirement of a large-capacity communication scene cannot be met.

Therefore, the method makes full use of the propagation characteristics of millimeter waves, realizes the high-speed generation of the physical layer key in the static environment in the millimeter wave wireless communication system, meets the encryption requirement of the communication scene of mass data, and is one of the important directions for the development of the physical layer key generation technology.

Through the above analysis, the problems and defects of the prior art are as follows:

(1) conventional secure communication mechanisms may face a number of challenges in new communication scenarios or technologies, including being unable to meet ultra-low latency requirements in specific communication scenarios, being difficult to distribute and manage keys among heterogeneous internet of things devices, breaking existing encryption algorithms by emerging computing devices, and the like.

(2) Most of current research schemes for generating the physical layer key are concentrated in a microwave frequency band below 6GHz, and cannot be applied to a communication system in a millimeter wave frequency band.

(3) The key generation rate of the traditional scheme is limited by a static environment, in the static environment, the channel changes slowly, the channel correlation time is long, the key generation rate is low, and the encryption requirement of a large-capacity communication scene cannot be met.

A physical layer key is generated in a millimeter wave communication system, which is different from a microwave system. Firstly, due to the propagation characteristics of millimeter wave high loss and weak diffraction capability, a traditional channel model for generating a physical layer key in a microwave system cannot be applied to a communication system in a millimeter wave frequency band, and a channel model conforming to the sparse characteristic of the channel needs to be established. In addition, the generation rate of the physical layer key in the conventional scheme is limited by a static environment, especially in a millimeter wave system, a channel between a communication party A and a communication party B mainly consists of a limited number of paths, the channel changes slowly, the relevant time of the channel is long, the principle of generating the physical layer key by only detecting the channel once in the relevant time of the conventional scheme is followed, and the generation rate of the key is low, so that the encryption requirement of a large-capacity communication scene cannot be met.

The method, the system and the equipment are suitable for the hardware structure of a millimeter wave system, and realize the generation of the key of the physical layer by utilizing the sparsity of a millimeter wave channel. By using the method of the invention of random beam switching, under the condition of ensuring the randomness of the secret key, a plurality of limited distinguishable beams between the A and B of the two communication parties are utilized, and the generation rate of the secret key of the physical layer of the method, the system and the equipment breaks through the limitation of a static environment. Under the current conditions of increasingly scarce spectrum resources and continuously increased communication data volume, the method, the system and the equipment obviously improve the rate of generating the physical layer key, so that the method, the system and the equipment can be suitable for a millimeter wave communication system and a high-capacity communication scene, and meet the development requirements of a communication technology which is different day by day.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a millimeter wave physical layer key generation method and system for random beam switching, and particularly relates to a technology in the process of generating a physical layer key in a millimeter wave large-scale MIMO system.

The invention is realized in such a way, and the millimeter wave physical layer key generation method for random beam switching comprises the following steps:

step one, a communication party A and a communication party B perform initial channel detection to obtain state information of a millimeter wave channel;

after the initial channel detection process in the first step, the two communication parties a and B obtain the channel state information of the current time, including the spatially resolved path and the arrival angle, departure angle and channel gain corresponding thereto. The invention lays a foundation for generating the millimeter wave physical layer key by subsequently switching the random wave beam.

Step two, generating a physical layer key for random beam switching;

in this step, both communication parties perform channel detection of random beam switching, and further generate a physical layer key, so that high-rate physical layer key generation in a static environment-related time is realized, which is a core step of the present invention.

And step three, performing physical layer key combination.

In the last step of the invention, the two communication parties A and B sequentially combine the physical layer keys generated in the step two according to the key generation time sequence relation, thereby ensuring the consistency of the key combination between the two communication parties A and B.

Further, in step one, the initial channel sounding includes:

(1) before generating a physical layer key, a communication party A and a communication party B agree to uniformly quantize the azimuth angle of a millimeter wave beam to N according to the size of a sine value, namely, each angle satisfies the following formula:

where θ is the azimuth of the beam.

(2) Two communication parties A and B transmit orthogonal reference signals X to each other in a time division duplex mode in a static environment correlation time_ABAnd X_BA. At a certain time, the communication party A transmits a reference signal X to the communication party B_ABPassing through t_ABAfter the time, the communication partner B receives the signal Y_B(ii) a The communication party B sends the reference signal X to the communication party A after the processing time delay of delta t time_BACommunication party A passes time t_BAAfter receiving signal Y_A(ii) a Two communication parties carry out primary channel bidirectional detection, and the total time of the primary channel bidirectional detection meets t_AB+Δt+t_BA≤T_c(ii) a Wherein T is_cIs the radio channel correlation time.

Further, in step two, the generating of the millimeter wave physical layer key for random beam switching includes:

(1) both communication parties A and B receive signal Y_AAnd Y_BAnd estimating a millimeter wave channel, acquiring L spatially distinguishable scattering paths meeting the millimeter wave communication requirement, acquiring L pieces of sparsity response coordinate information corresponding to the L spatially distinguishable scattering paths, and matching the arrival angle and the departure angle of the beam path between the sender and the receiver.

(2) And (3) the two communication parties A and B use the millimeter wave channel sparsity response coordinates obtained in the step (1) as a random source for generating the physical layer key, and generate a first group of physical layer keys in the channel correlation time in the static environment by combining the corresponding relation between the arrival angle and the departure angle of the wave beam.

(3) A communication party A (B) randomly generates an integer zeta ∈ {1,2, …, L }, wherein L is the number of millimeter wave channel space distinguishable scattering paths between the communication parties A and B, namely the number of sparsity response coordinates obtained in the step (1); the random integer ζ is used to select the number of beams activated by the communication party that is the transmission side for the secondary channel sounding.

(4) According to the random selection result of the step (3), the communication party A (B) randomly generates an integerFor selecting a combination of active beams; the beam combination for the sending end to switch is 2 based on the generation of random integers zeta and delta^L-1 species.

(5) The communication party A (B) is used as a sending end, corresponding beams are activated according to the integers zeta and delta randomly selected in the steps (3) and (4), and the reference signal X is sent on the activated beams_AB(X_BA) And generating a sending end key according to the beam selection result and the relation between the arrival angle and the departure angle of the beam in the step (1).

(6) The communication party B (A) as the receiving end receives the signal Y_B(Y_A) And estimating a millimeter wave channel, and extracting a millimeter wave channel sparsity response coordinate after the wave beam selection as a random source.

(7) And (4) the communication party B (A) is used as a receiving end, and generates a physical layer key according to the channel estimation result in the step (6) and the relationship between the initial channel detection result in the step (1) and the arrival angle and departure angle of the beam.

(8) And (4) the two communication parties can repeatedly execute the steps (3) to (7), the beam combination is randomly switched to perform channel detection, and more keys are generated in the relevant time under the condition of ensuring the randomness of the keys.

Further, in the step (1) and the step (6), the millimeter wave channel estimation process includes:

step (1) receiving a reference signal Y_AAnd Y_BThe following were used:

Y_A＝H_BAX_BA+Q_BA；

Y_B＝H_ABX_AB+Q_AB；

step (6) receiving a reference signal Y_AAnd Y_BThe following were used:

Y_A＝H_BAX_BAV_s+Q_BA；

Y_B＝H_ABX_ABV_s+Q_AB；

wherein H_ABAnd H_BARespectively representing the channel matrix of party A to party B and the channel matrix of party B to party A, V_sA pre-coding matrix representing a transmitting side, which is used for selecting an active beam combination; q_ABAnd Q_BAIs complex Gaussian noise which is independently and equally distributed;

because two communication parties A and B carry out bidirectional channel detection in the relevant time of the channel, two channel matrixes satisfy H according to the reciprocity principle of a wireless channel_AB＝H_BA ^H. Therefore, only the processing procedure of the signal received by the communication party a transmitting the communication party B is analyzed, and the processing procedure of the signal received by the communication party B transmitting the communication party a is the same.

Adopting a DFT codebook to perform precoding reception on a received signal so as to obtain sparsity information of a millimeter wave channel; wherein the obtained channel matrix H of millimeter wave_ABEquivalent sparse channel matrixThe following were used:

wherein A is_B,DAnd A_A,DDFT codebooks, X, representing correspondent B and correspondent A, respectively_ABFor quadrature reference signals, Q_ABIn order to be a complex noise matrix,represents a millimeter wave sparse channel matrix (virtual matrix) capable of equivalently representing a millimeter wave channel matrix H_AB：

The channel millimeter wave channel established based on the ray cluster theory is as follows:

wherein, L represents the number of multipath, namely the number of ray clusters; alpha is alpha_lRepresents the channel complex gain of the ith path, i.e., the ith cluster, an Satisfy the requirement ofθ_A,lAnd phi_B,lThe arrival angle and the departure angle, a (theta), corresponding to the ith path_A,l) And a (phi)_B,l) Respectively representing the arrival angles of the receiving ends as theta_A,lAnd a departure angle from the transmitting end of phi_B,lULA array response vector of, N_t＝N_AAnd N_r＝N_BRespectively, the number of antennas of the transmitting side and the receiving side, where a (theta)_A,l) And a (phi)_B,l) Expressed as:

the distance d of the uniform linear array element antenna is equal to lambda/2, and lambda is the wavelength of a transmission signal.

Further, after obtaining the distinguishable path combination between the two communication parties a and B, the two communication parties a and B match the beams between the sender and the receiver, specifically as follows:

when the number of antennas is different between the transmitting side and the receiving side, the respective spatial resolutions N are also different. After the initial channel detection, the two communication parties A and B obtain the corresponding relation between the arrival angle and the departure angle of the beam between the two communication parties according to the channel detection result. That is, there may be three correspondences between beam departure angle and arrival angle:

one-to-many: the number of antennas at the transmitting side is less than the number of antennas at the receiving side.

Two-to-one: the number of antennas at the transmitting side is greater than the number of antennas at the receiving side.

③ one-to-one: the number of antennas at the sender is equal to the number of antennas at the receiver.

For the above three cases, the corresponding situation between the arrival angle and the departure angle of the beam between the transmitting side and the receiving side can be obtained by combining the channel estimation result in step (1).

Further, in the step (2), acquiring sparse response coordinates in the millimeter wave sparse channel as a random source for generating the physical layer key, including:

obtaining a virtual channel matrixSparsity response information that may exist in the beam angle-of-arrival direction:

a communication party B as a receiving end obtains a set of sparse response coordinates J and a corresponding set of channel response amplitudes V that may exist in the direction of the beam angle of arrival.

The communication party B as the receiving end acquires sparse response information, and the sparse response information comprises the following steps:

the communication party B sets L to 0, that is, initializes the number of spatially resolved scattering paths, and extracts the current maximum gain beam information:

the communication party B executes the step of extracting the current maximum gain beam information and judges the current maximum gain beam information V (i)_max) Whether the condition 1 is met or not, if so, executing the step corresponding to the condition 1; after the step of extracting the current maximum gain beam information is executed, the step of extracting the current maximum gain beam information is executed in a circulating mode again until V (i)_max) Until condition 2 is satisfied.

Condition 1: if V (i) is satisfied_max) If the epsilon is a channel path gain critical value, the wave beam in the direction meets the millimeter wave communication requirement, namely sparse response exists; extracting sparsity response information corresponding to the beam, updating a channel response amplitude set V, and deleting the current best beam information to estimate other beam information, wherein the sparsity response information comprises:

G(j)＝V(i_max)；

V(i_max)＝0；

L＝L+1；

condition 2: if V (i)_max) If the epsilon is less than epsilon, the residual path information does not meet the requirement of millimeter wave channel gain, so the channel estimation process is finished.

V(i_max) When the condition 2 is satisfied, the channel estimation is finished, the receiving party obtains the quantity L of the space distinguishable scattering paths between the two communication parties,for the set of virtual channel response impulse coordinates corresponding to the beam angle-of-arrival in the channel estimation result,a coordinate set corresponding to the beam departure angle; g is the set of channel gains for each path.

Further, in the step (2), a Gray code table is used as a key lookup table to complete mapping between the coordinates and the key; wherein the key mapping step comprises:

determining the sequence number of the sparse response coordinate in the virtual channel matrix, wherein the sequence number arrangement method is that k is (x-1) N + y-1, wherein k is the sequence number corresponding to the sparse response coordinate (x, y), x belongs to {1,2, …, N }, and y belongs to {1,2, …, N }; looking up a gray code sequence corresponding to the decimal number k in an I-bit gray code table as a key sequence, wherein

When the correspondence between the arrival angle and the departure angle of the beam obtained in step (1) is "many-to-one" or "one-to-many", that is, the sparsity response coordinate set or the subset thereof has the following form:

{(x₁,y),...,(x_n,y)}；

{(x,y₁),...,(x,y_n)}；

the multiple angles are divided into a group and mapped to the same coordinate value, namely when one or more beams are activated in the group, the generated physical layer keys are the same.

The two communication parties A and B obtain a first group of keys k in the relevant time of the channel by using the key mapping method to complete the mapping between the sparse response coordinate set obtained in the step (1) and the physical layer key sequence_A(B)，0。

Further, in step (5), according to the random selection results in steps (3) and (4), the transmitting side obtains a combination of random switched beams, transmits a reference signal in the selected beam, and the receiving side can obtain the same combination of activated beams equivalent to the transmitting side by performing a channel estimation process similar to step (1).

Further, in step (6), considering the correspondence between the arrival angle and the departure angle of the three beams in step (1), generating a physical layer key of the transmitting end by combining the beam combination condition activated and transmitting the reference signal in step (5) and the key mapping algorithm in step (2), specifically as follows:

when there is a case of many-to-one or one-to-many between the beam departure angle and the arrival angle in step (1), and when the party with a large number of angles uses the key mapping method in step (2), the angles are divided into a group and mapped to the same coordinate value, that is, when one or more beams are activated in the group, the generated physical layer keys are the same.

Further, in step (7), after the receiving side performs channel estimation, if there is a case of many-to-one or one-to-many between the beam departure angle and the arrival angle in the estimation result, and the party with the larger number of angles uses the key mapping method in step (2), the plurality of angles are divided into a group and mapped to the same coordinate value, that is, when one or more active beams are detected by the group of beams in the channel estimation result, the generated physical layer keys are the same.

Further, in step three, the physical layer key combination includes that the two communication parties a and B perform step two for multiple times within the relevant time, multiple groups of keys are obtained through random beam switching, and the keys are combined according to the time sequence, so that the millimeter wave physical layer key switched by the random beam can be obtained, including:

based on the assumption that the channel state is unchanged in the channel correlation time, if the millimeter wave physical layer key generation for random beam switching is performed n times, the keys obtained by the two communication parties a (b) in the channel correlation time are:

wherein k is_A(B),iAndi belongs to {1,2, …, n } is a physical layer key generated by the sending and receiving of the ith time of a legal communication party A (B); k_A(B),τRepresenting the physical layer key generated during the channel correlation time.

Another object of the present invention is to provide a millimeter wave physical layer key generation system for random beam switching, which applies the millimeter wave physical layer key generation method for random beam switching, and the millimeter wave physical layer key generation system for random beam switching includes:

the channel detection module is used for carrying out initial channel detection on the communication parties A and B to obtain state information of the millimeter wave channel;

the key generation module is used for generating a physical layer key for random beam switching;

and the key combination module is used for carrying out physical layer key combination to obtain a millimeter wave physical layer key switched by random beams.

It is a further object of the invention to provide a computer device comprising a memory and a processor, the memory storing a computer program which, when executed by the processor, causes the processor to perform the steps of:

the communication parties A and B carry out initial channel detection to obtain state information of a millimeter wave channel; generating a physical layer key for random beam switching; and combining physical layer keys, namely, performing random beam switching multiple times by the two communication parties A and B in related time to generate a physical layer key, obtaining multiple groups of keys through random beam switching, and combining the keys according to a time sequence to obtain a millimeter wave physical layer key switched by random beams.

Another object of the present invention is to provide an information data processing terminal, which is used for implementing the millimeter wave physical layer key generation system for random beam switching.

By combining all the technical schemes, the invention has the advantages and positive effects that: the millimeter wave physical layer key generation method for random beam switching is one of important technologies in the field of key security communication, can break through the limitation of a static environment on the key generation rate in a millimeter wave wireless communication system, and solves the problem that the traditional scheme cannot meet the encryption requirement of a mass data communication scene due to the low key generation rate in the static environment.

The method of the invention utilizes the sparsity of the millimeter wave channel and selects the coordinates of the sparsity response of the millimeter wave channel as a random source for generating the physical layer key. By the method of random beam switching, a new method of physical layer key generation is realized, which carries out channel detection for many times in a static environment to generate a physical layer key without destroying the randomness of the key. Theoretical analysis and simulation results show that the key generation rate of the method breaks through the limit of the relevant time of the channel; the keys before key agreement have higher consistency, so that the expenditure of the key agreement and the privacy amplification process is saved; and the method can resist the passive eavesdropper with multiple antennas.

Compared with the traditional scheme for millimeter wave channel estimation, the method provided by the invention has the advantages that the sparsity of the millimeter wave channel is utilized, the complexity of the channel estimation process is lower, the noise resistance is better, the consistency between the physical layer keys generated after the channels of the two communication parties are detected is higher, and the expenses of the key negotiation and privacy amplification process in the physical layer key generation process can be saved. Compared with the channel detection process of the traditional scheme, the random beam switching channel detection method used by the method not only ensures the safety of physical layer key generation, but also has the capability of resisting multi-antenna passive eavesdroppers, and obviously improves the key generation rate, so that the method breaks through the limitation of a static environment and can meet the encryption requirement of a mass data communication scene.

The millimeter wave physical layer key generation method for random beam switching provided by the invention solves the problem of low key generation rate in a static environment in the traditional scheme by using a millimeter wave channel detection scheme for random beam switching in a millimeter wave system, and obtains higher key consistency rate and capability of resisting a passive eavesdropper. The random source and the key mapping algorithm used for generating the physical layer key in the method have replaceability, and the physical layer key with high speed in the static environment can still be generated by selecting other channel characteristics as the random source or combining the channel estimation method with the channel detection method for random beam switching provided by the method.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of a millimeter wave physical layer key generation method for random beam switching according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of a millimeter wave physical layer key generation method for random beam switching according to an embodiment of the present invention.

Fig. 3 is a block diagram of a millimeter wave physical layer key generation system for random beam switching according to an embodiment of the present invention;

in the figure: 1. a channel detection module; 2. a key generation module; 3. and a key combination module.

Fig. 4 is a schematic diagram of a timing model according to an embodiment of the present invention.

Fig. 5 is a schematic diagram of an active beam according to an embodiment of the present invention.

Fig. 6 is a schematic diagram of random beam switching according to an embodiment of the present invention.

Fig. 7 is a diagram of physical layer key generation rate results obtained by an embodiment of the present invention.

Fig. 8 is a diagram of the physical layer key inconsistency rate results obtained by the embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In view of the problems in the prior art, the present invention provides a method and a system for generating a millimeter wave physical layer key for random beam switching, which are described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the method for generating a millimeter wave physical layer key for random beam switching according to the embodiment of the present invention includes the following steps:

s101, carrying out initial channel detection by a communication party A and a communication party B to obtain state information of a millimeter wave channel;

s102, generating a physical layer key for random beam switching;

and S103, carrying out physical layer key combination.

A schematic diagram of a millimeter wave physical layer key generation method for random beam switching according to an embodiment of the present invention is shown in fig. 2.

As shown in fig. 3, the millimeter wave physical layer key generation system for random beam switching according to the embodiment of the present invention includes:

the channel detection module 1 is used for performing initial channel detection on a communication party A and a communication party B to obtain state information of a millimeter wave channel;

a key generation module 2, configured to generate a physical layer key for performing random beam switching;

and the key combination module 3 is used for carrying out physical layer key combination to obtain a millimeter wave physical layer key switched by random beams.

The technical solution of the present invention will be further described with reference to the following examples.

Example 1

The invention discloses a millimeter wave physical layer key generation method for random beam switching, which can break through the limitation of a static environment on the key generation rate in a millimeter wave wireless communication system and solve the problem that the traditional scheme cannot meet the encryption requirement of a mass data communication scene due to the low key generation rate in the static environment.

In order to solve the above problem, the present invention provides a method for generating a random beam switching millimeter wave physical layer key, including the following steps:

the method comprises the following steps: initial channel sounding. In order to obtain the channel state information between the two communication parties A and B, the method carries out initial channel detection and comprises the following steps:

step 1: before generating a physical layer key, a communication party A and a communication party B agree to uniformly quantize the azimuth angle of a millimeter wave beam into N according to the size of the sine value of the millimeter wave beam.

Step 2: two communication parties A and B transmit orthogonal reference signals X to each other in a time division duplex mode in a static environment correlation time_ABAnd X_BA。

Step two: physical layer key generation for random beam switching. The method for improving the generation rate of the physical layer key in the static environment comprises the following steps:

step 1: both communication parties A and B receive signal Y_AAnd Y_BAnd estimating a millimeter wave channel, acquiring L spatially distinguishable scattering paths meeting the millimeter wave communication requirement, and acquiring information of L corresponding sparsity response coordinates and a corresponding relation between a beam arrival angle and a beam departure angle.

Step 2: and (3) the two communication parties A and B use the millimeter wave channel sparsity response coordinates obtained in the step (1) as a random source for generating the physical layer key to generate a first group of physical layer keys in the channel correlation time in the static environment.

And step 3: party a (b) randomly generates an integer ζ e {1,2, …, L } for selecting the number of active beams.

And 4, step 4: according to the random selection result of step 3, the communication party A (B) randomly generates an integerFor selecting the combination of active beams.

And 5: the communication party A (B) is used as a sending end, activates corresponding beams according to the integers zeta and delta randomly selected in the steps 3 and 4, and sends the reference signal X on the activated beams_AB(X_BA) And generating a sending end key according to the beam selection result and the corresponding relation between the arrival angle and the departure angle of the beam in the step 1.

Step 6: the communication party B (A) as the receiving end receives the signal Y_B(Y_A) And estimating a millimeter wave channel, and extracting a millimeter wave channel sparsity response coordinate after the wave beam selection as a random source.

And 7: and the communication party B (A) is used as a receiving end, and generates a physical layer key according to the channel estimation result in the step 6 and the corresponding relation between the initial channel detection result in the step 1 and the arrival angle and the departure angle of the wave beam.

And 8: and (3) the two communication parties can repeatedly execute the step 3 to the step 7, the beam combination is randomly switched to carry out channel detection, and more keys are generated in the relevant time under the condition of ensuring the randomness of the keys.

Step three: and combining the physical layer keys. And (4) the two communication parties A and B execute the step two for multiple times in relevant time, multiple groups of keys are obtained through random beam switching, and the keys are combined according to the time sequence, so that the millimeter wave physical layer key of the random beam switching can be obtained.

The method utilizes the sparsity of the millimeter wave channel, compared with the traditional scheme for millimeter wave channel estimation, the method has the advantages that the complexity of the channel estimation process is lower, the noise resistance is better, the consistency between the keys of the physical layer generated after the channels of the two communication parties are detected is higher, and the expenses of the key negotiation and privacy amplification process in the key generation process of the physical layer can be saved; compared with the channel detection process of the traditional scheme, the random beam switching channel detection method used by the method disclosed by the invention not only ensures the safety of physical layer key generation, has the capability of resisting multi-antenna passive eavesdroppers, but also obviously improves the key generation rate, so that the method breaks through the limitation of a static environment and can meet the encryption requirement of a mass data communication scene.

Example 2

As shown in fig. 2, the present invention provides a method for generating a physical layer key suitable for random beam switching in a millimeter wave system, which includes the following steps.

The method comprises the following steps: and the communication parties A and B carry out channel initial detection to obtain the channel state information of the millimeter wave channel.

Step 1: the communication parties A and B uniformly quantize the azimuth angle of the millimeter wave beam into N according to the sine value of the millimeter wave beam, namely, each angle satisfies the following formula:

where θ is the azimuth of the beam.

Step 2: as shown in FIG. 4, two communicating parties A and B respectively transmit a reference signal X to each other_ABAnd X_BA. At a certain time, the communication party A transmits a reference signal X to the communication party B_ABPassing through t_ABAfter the time, the communication partner B receives the signal Y_B. The communication party B sends the reference signal X to the communication party A after the processing time delay of delta t time_BACommunication party A passes time t_BAAfter receiving signal Y_A. The two communication parties in the process carry out primary channel bidirectional detection, and the total time of the primary channel bidirectional detection needs to meet t_AB+Δt+t_BA≤T_cWherein T is_cIs the radio channel correlation time.

Step two: millimeter wave physical layer key generation for random beam switching

Step 1: in the process of acquiring the random source by the two communication parties A and B, the millimeter wave channel estimation process is as follows:

initial channel sounding received reference signal Y_AAnd Y_BThe following were used:

Y_A＝H_BAX_BA+Q_BA

Y_B＝H_ABX_AB+Q_AB

wherein H_ABAnd H_BAThe channel matrix of the communication party a to the communication party B and the channel matrix of the communication party B to the communication party a are respectively represented. Q_ABAnd Q_BAIs independently and equally distributed complex gaussian noise. Because both communication parties A and B carry out bidirectional channel detection in the relevant time of the channel, according to the reciprocity principle of the wireless channel, two channel matrixes satisfy H_AB＝H_BA ^H. Therefore, only the signal processing procedure of the communication party a transmitting the signal received by the communication party B is analyzed below, and the signal processing procedure of the communication party B transmitting the signal received by the communication party a is the same.

In the method of the invention, in order to obtain sparsity information of a millimeter wave channel, DFT codebook is adopted for receivingThe signals are received in a pre-coding mode to obtain a millimeter wave channel matrix H_ABEquivalent sparse channel matrixThe following were used:

wherein A is_B,DAnd A_A,DDFT codebooks respectively representing communication partner B and communication partner a.Represents a millimeter wave sparse channel matrix and can equivalently represent a millimeter wave channel H_AB。

The channel millimeter wave channel established based on the ray cluster theory may be as follows:

wherein, L represents the number of multipath, namely the number of ray clusters; alpha is alpha_lRepresents the channel complex gain of the ith path, i.e., the ith cluster, an Satisfy the requirement ofθ_A,lAnd phi_B,lThe arrival angle and the departure angle, a (theta), corresponding to the ith path_A,l) And a (phi)_B,l) Respectively representing the arrival angles of the receiving ends as theta_A,lAnd a departure angle from the transmitting end of phi_B,lULA array response vector of, N_t＝N_AAnd N_r＝N_BRespectively, the number of antennas of the transmitting side and the receiving side, where a (theta)_A,l) And a (phi)_B,l) Expressed as:

and taking the uniform linear array element antenna distance d as lambda/2. λ is the wavelength of the transmission signal.

Further acquiring sparse response coordinates in a millimeter wave sparse channel as a random source for generating a physical layer key, wherein the steps are as follows:

obtaining a virtual channel matrixSparsity response information possibly existing in the direction of the beam arrival angle is as follows:

through the above steps, the communication party B as the receiving end obtains a set of sparse response coordinates J and a corresponding set of channel response amplitude V that may exist in the beam arrival angle direction.

In the method of the invention, a communication party B as a receiving end further acquires sparse response information, and the method comprises the following steps:

first, the communication party B sets L to 0, i.e., initializes the number of spatially resolved scattering paths. Further, extracting the current maximum gain beam information as follows:

the communication party B executes the steps shown in the above formula, and judges the current beam information V (i) with the maximum gain_max) And whether the condition 1 is met or not, and if so, executing the step corresponding to the condition 1. After the execution, the steps shown in the above formula are circularly executed again until V (i)_max) Until condition 2 is satisfied.

Condition 1: if V (i) is satisfied_max) And if the epsilon is the channel path gain critical value, the wave beam in the direction meets the millimeter wave communication requirement, namely sparse response exists. Then, extracting sparsity response information corresponding to the beam, updating a channel response amplitude set V, and deleting the current best beam information to facilitate further estimation of other beam information, the steps are as follows:

G(j)＝V(i_max)

V(i_max)＝0

L＝L+1

condition 2: if V (i)_max) If the epsilon is less than epsilon, the residual path information does not meet the requirement of millimeter wave channel gain, so the channel estimation process of the method of the invention is finished.

V(i_max) When the condition 2 is satisfied, the channel estimation is finished, the receiving side obtains the number L of the spatial distinguishable scattering paths,for the set of virtual channel response impulse coordinates corresponding to the beam angle-of-arrival in the channel estimation result,is a set of coordinates corresponding to the beam departure angle. G is the set of channel gains for each path.

Further, after obtaining the distinguishable path combination between the two communication parties a and B, the two communication parties a and B match the beams between the sender and the receiver, specifically as follows:

when the number of antennas is different between the transmitting side and the receiving side, the respective spatial resolutions N are also different. After the initial channel detection, the two communication parties A and B obtain the corresponding relation between the arrival angle and the departure angle of the beam between the two communication parties according to the channel detection result. That is, there may be three correspondences between beam departure angle and arrival angle:

one-to-many: the number of antennas at the transmitting side is less than the number of antennas at the receiving side.

Two-to-one: the number of antennas at the transmitting side is greater than the number of antennas at the receiving side.

③ one-to-one: the number of antennas at the sender is equal to the number of antennas at the receiver.

For the above three cases, the corresponding situation between the arrival angle and the departure angle of the beam between the transmitting side and the receiving side can be obtained by combining the channel estimation result in step 1.

Step 2: and B, the two communication parties A and B use the millimeter wave channel sparsity response coordinate obtained in the step as a random source to generate a physical layer key. The key mapping steps are as follows:

and determining the serial number of the sparse response coordinate in the virtual channel matrix, wherein the serial number is arranged in a way that k is (x-1) N + y-1. Wherein k is a sequence number corresponding to the sparsity response coordinate (x, y), x belongs to {1,2, …, N }, and y belongs to {1,2, …, N }. When the correspondence between the arrival angle and the departure angle of the beam obtained in step (1) is "many-to-one" or "one-to-many", that is, the sparsity response coordinate set or the subset thereof has the following form:

{(x₁,y),...,(x_n,y)}；

{(x,y₁),...,(x,y_n)}；

the multiple angles are divided into a group and mapped to the same coordinate value, namely when one or more beams are activated in the group, the generated physical layer keys are the same.

Finding decimal in I-bit Gray code tableAnd a gray code sequence corresponding to the system number k is used as a key sequence. Wherein

The two communication parties A and B complete the mapping between the sparse response coordinate set obtained in the step 1 and the physical layer key sequence by using the key mapping method to obtain a first group of keys k in the channel correlation time_A(B)，0。

And step 3: and (B) generating a random integer zeta ∈ {1,2, …, L }, wherein L is the number of millimeter wave channel space-resolvable scattering paths, namely the number of sparsity response coordinates obtained in the step 1. As shown in fig. 5, the random integer ζ determines the number of beams activated by the communication party as the transmitting party in the method of the present invention. For example, ζ ═ m, m ∈ {1,2, …, L } indicates that only m of the L active beams are active at this stage.

And 4, step 4: next, the communication party A (B) generates the random integer againAnd selecting a beam combination mode.

Based on the generation of random integers ζ and δ, the beam combination for the sending end to switch is 2^L-1 species. For example, as shown in fig. 5, when the number L of spatially resolved scattering paths is 5 and the randomly generated integer ζ is 3, the number of alternative beam combinations is as follows:

indicating that there are 10 beam combinations available for handover in this case.

Wherein e_L,ζRepresenting the set of beam states when the number of active beams is ζ, if an integer is randomly generatedδ equals 7, then the beam state vector e equals [ 10110 ═ then]^TWherein e is_i1 denotes that the ith beam is activated, e_j0 means that the jth beam is not used, i, j e {1,2, …, L }. δ ═ 7 and e ═ 10110]^TIt is indicated that 7 of the 10 beam combinations are selected for channel detection, i.e. the 1 st, 3 rd and 4 th beams are activated, as shown in fig. 6 (b).

And 5: the communication party A (B) is used as a sending end, and selects an active beam to send a reference signal X according to the random numbers zeta and delta generated in the steps 3 and 4_AB(X_BA). In a static environment, millimeter wave channel detection of random beam switching is carried out in a channel-related time, and the channel state is unchanged, so that a sending party A (B) and a receiving party B (A) can obtain a consistent beam combination.

The transmitting side a (b) has already learned the entire channel information in the initial channel sounding phase. Therefore, after the beam combination in the random beam switching stage is obtained according to the random numbers ζ and δ, the theoretical key of the sender a (b) is generated according to the key mapping method described above. For example, when the beam state vector e is [ 10110 ]]^TAt this time, the 1 st, 3 rd, 4 th beams are activated. The sender A (B) extracts the coordinates (x) of the 1 st, 3 rd and 4 th beams₁,y₁)、(x₃,y₃)、(x₄,y₄) Sequentially mapping the secret keys to generate a secret key sequence k_A(B),1＝[k₁k₃ k₄]When there is a case of many-to-one or one-to-many between the beam departure angle and the arrival angle in step (1), and when the party with a large number of angles uses the key mapping method in step (2), the angles are divided into a group and mapped to the same coordinate value, that is, when one or more beams are activated in the group, the generated physical layer keys are the same.

Step 6: the communication party B (A) receives the reference signal X_BA(X_AB) The following were used:

Y_A＝H_BAX_BAV_s+Q_BA；

Y_B＝H_ABX_ABV_s+Q_AB；

V_srepresenting the senderA precoding matrix.

By performing the channel estimation process described above in the method of the present invention, the same beam combination as that of the sender a (b) can be obtained.

And 7: further, according to the result of channel estimation, the physical layer key of the receiver b (a) can be obtained by executing a key mapping method. For example, when the channel estimation result e is [ 10110 ]]^TWhen receiving party b (a) detects that the 1 st, 3 rd, 4 th beams are activated. The receiving party B (A) extracts the coordinates (x) of the 1 st, 3 rd and 4 th beams₁,y₁)、(x₃,y₃)、(x₄,y₄) Sequentially mapping the secret keys to generate a secret key sequence k_B(A),1＝[k₁ k₃ k₄]If there is a case of many-to-one or one-to-many between the beam departure angle and the arrival angle in the estimation result, when the party with a large number of angles uses the key mapping method of step 2, the multiple angles are divided into a group and mapped to the same coordinate value, that is, when one or more active beams are detected by the group of beams in the channel estimation result, the generated physical layer keys are the same.

And 8: the method of the invention aims to solve the problem of low generation rate of the physical layer key in the static environment. As shown in fig. 6, the two communication parties a and B perform steps 3 to 7 multiple times within the channel correlation time, and by the beam switching as shown in fig. 6, the key generation rate performance is significantly improved within the channel correlation time, so that the limitation of the static environment is broken through.

Step three: based on the assumption that the channel state is unchanged in the channel correlation time, if millimeter wave physical layer key generation of random beam switching is performed for n times, the method of the invention obtains keys in the channel correlation time by both communication parties A (B) as follows:

wherein k is_A(B),iAndi e {1,2, …, n } is the physical layer key generated by the legitimate correspondent a (b) sending and receiving the ith time. K_A(B),τRepresenting the physical layer key generated based on the method of the present invention during the channel correlation time.

The millimeter wave physical layer key generation method for random beam switching provided by the invention solves the problem of low key generation rate in a static environment in the traditional scheme by using a millimeter wave channel detection scheme for random beam switching in a millimeter wave system, and obtains higher key consistency rate and capability of resisting a passive eavesdropper. The random source and the key mapping algorithm used for generating the physical layer key in the method have replaceability, and the physical layer key with high speed in the static environment can still be generated by selecting other channel characteristics as the random source or combining the channel estimation method with the channel detection method for random beam switching provided by the method.

The technical effects of the present invention will be described in detail with reference to experiments.

According to the description of the method, a simulation model is established to perform simulation verification on the performance of the method. For the convenience of analysis, on the premise of not changing the system design, the key generation rate and the key inconsistency rate data of the simulation are both based on the analysis of the key data obtained by using the received signal by one of the parties in the legal communication, and the user described in embodiment 3 completes one-time reception and transmission of the generated key data. Since the key data obtained based on the received signal already reflects the overall performance of the system, selecting the data for simulation does not affect the credibility of the simulation result.

As shown in fig. 7, under the condition that the beam resolution N is 128 and the number of antennas at the transmitting side and the receiving side is equal, the simulation compares the key generation rate performance of the physical layer key generation scheme based on the sparsity response coordinate without random beam switching and the method of the present invention. Simulation results show that the key generation rate performance of the scheme is continuously improved along with the increase of the switching times n, and better key generation rate performance can be obtained only by meeting the condition that the switching times n are more than 1, so that the problem that the key generation rate performance of the traditional scheme is poorer in a static environment is solved.

Further simulation verifies the key inconsistency rate performance of the method of the present invention, as shown in fig. 8, in order to verify the influence of the exploration beam resolution N on the system reliability, under the condition of different SNRs, N is made to be N_r＝N_tThe number of spatially distinguishable paths L is 5, and the number of random beam switching ζ_tUnder the condition of 3, the random beam switching-based detection is performed 24 times in the correlation time. Simulation results show that under the same SNR condition, the larger the beam resolution is, the better the anti-noise performance of the method is, and the better the inconsistency rate performance between generated physical layer keys is.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When used in whole or in part, can be implemented in a computer program product that includes one or more computer instructions. When loaded or executed on a computer, cause the flow or functions according to embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center via wire (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL), or wireless (e.g., infrared, wireless, microwave, etc.)). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that includes one or more of the available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.