Cognitive radio network, cognitive user power allocation method and secure communication method

Abstract

The cognitive user power allocation method for cognitive radio network comprises the following steps: determining a time segmentation ratio, and segmenting a communication time slot of the cognitive radio network into a front time slot and a rear time slot based on the time segmentation ratio; the cognitive user receives a pilot signal sent by a licensed user in the front time slot, and obtains pilot energy from the pilot signal; and the cognitive user determines actual transmission power based on the time segmentation ratio, the pilot energy and initial energy of the cognitive user. The cognitive user power allocation method for cognitive radio network and the safe communication method can significantly improve the energy shortage problem of the cognitive user, prolong the service life of the cognitive radio network, and ensure the communication performance.

Description

Technical Field

[0001] This invention relates to the field of cognitive wireless network technology, specifically to a cognitive user power allocation method and a secure communication method for cognitive wireless networks. Background Technology

[0002] Cognitive Radio Networks (CRNs) are an effective method to alleviate spectrum resource shortages and improve spectrum efficiency. In existing technologies, utilizing cognitive user cooperative communication can effectively enhance network security. Specifically, on the one hand, the transmission of cognitive user data itself is a form of interference for eavesdroppers; on the other hand, because cognitive users and eavesdropping users share some similar behavioral characteristics, such as the randomness and dynamism of user terminals, these similarities allow cognitive users to effectively track and intervene in eavesdropping activities. Therefore, cooperation among cognitive users can better enhance the physical layer security of authorized systems.

[0003] However, when cognitive users collaborate with authorized users, their energy consumption rate increases. Since cognitive users have very limited energy storage, the lifespan of cognitive users participating in the collaboration is shortened due to the rapid consumption of their own energy, which in turn leads to a decline in the overall user service quality and a shortened lifespan of the network. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a cognitive user power allocation method and a secure communication method for cognitive wireless networks, which can significantly improve the energy shortage problem of cognitive users, extend the lifespan of cognitive wireless networks, and ensure communication performance.

[0005] To achieve the above objectives, the specific solution adopted by the present invention is: a cognitive user power allocation method for cognitive wireless networks, comprising:

[0006] Determine the time segmentation ratio, and based on the time segmentation ratio, divide the communication time slots of the cognitive wireless network into a front time slot and a back time slot;

[0007] The cognitive user receives the pilot signal sent by the authorized user in the front time slot and extracts the pilot energy from the pilot signal;

[0008] The cognitive user determines the actual transmission power based on the time division ratio, pilot energy, and its own initial energy.

[0009] As a further optimization of the cognitive user power allocation method for the above-mentioned cognitive wireless network: the time segmentation ratio is the ratio of the front-end time slot to the communication time slot.

[0010] As a further optimization of the cognitive user power allocation method for the aforementioned cognitive wireless network: time division ratio Where C c To understand the instantaneous capacity of the user receiver, and Where μ (0≤μ≤1) is the time division ratio, and T is the total length of the communication time slot. To understand the user's basic transmission rate, P is the channel coefficient between the cognitive user transmitter and the cognitive user receiver. A For authorized users' transmit power, h AR N is the channel coefficient between the authorized user transmitter and the eavesdropping user, and N0 is the additive white Gaussian noise power.

[0011] As a further optimization of the cognitive user power allocation method for the aforementioned cognitive wireless network: the pilot energy obtained by the cognitive user from the pilot signal is... Where η (0≤η≤1) is the energy transfer efficiency. The channel conditions between the licensed user transmitter and the cognitive user transmitter.

[0012] As a further optimization of the cognitive user power allocation method for the aforementioned cognitive wireless network: the actual transmission rate of the cognitive user is Where I represents the maximum tolerable interference level. To define the channel conditions between the cognitive user transmitter and the licensed user receiver, P0 represents the cognitive user's basic transmit power, and there are... E0 represents the initial energy for understanding users.

[0013] Cognitive wireless network secure communication methods include the following steps:

[0014] S1. Before transmitting information, the authorized user transmitter sends a notification message to the authorized user receiver and the cognitive user transmitter.

[0015] S2. After receiving the notification information, the authorized user receiver broadcasts a pilot signal.

[0016] S3. The cognitive user transmitter collects the pilot signal energy of the licensed user transmitter and determines the actual transmission power based on the above method;

[0017] S4. The cognitive user transmitter selects whether to join the candidate set based on the communication status between the authorized user receiver and the authorized user transmitter and the cognitive user transmitter.

[0018] S5. The cognitive user transmitter calculates the communication parameters between the authorized user receiver, the cognitive user receiver, and the eavesdropping user, and sends them to the authorized user transmitter.

[0019] S6. The authorized user transmitter selects a cognitive user transmitter with the best transmission performance from the candidate set as the assisting communication user;

[0020] S7. The authorized user transmitter selects a cognitive user transmitter with the best security performance from the candidate set as the assisting jammer;

[0021] S8. The authorized user transmitter shares the authorized frequency band with the assisting communication user and the assisting interference user, and the assisting communication user transmits assisting communication information synchronously with the authorized user transmitter, and the assisting interference user transmits assisting artificial noise synchronously.

[0022] Beneficial effects: The cognitive user power allocation method for cognitive wireless networks of the present invention enables cognitive users to receive pilot signals transmitted by authorized users and obtain pilot energy from the pilot signals, and then conduct secure communication based on the pilot energy and their own initial energy. This can significantly improve the energy shortage problem of cognitive users, extend the service life of cognitive wireless networks, and balance the energy acquisition and information transmission of cognitive users by optimizing the time division ratio. Attached Figure Description

[0023] Figure 1 This is a comparison diagram of the energy collection and transmission modes of the cognitive wireless network in this invention;

[0024] Figure 2 This is a diagram of the traditional understanding of wireless network underlay mode;

[0025] Figure 3 This is a comparison chart showing the impact of the number of cognitive user transmitters on the connection interruption probability of authorized user transmitters in the present invention and the traditional scheme in a simulation experiment;

[0026] Figure 4 This is a comparison chart showing the impact of the number of cognitive user transmitters on the connection interruption probability of cognitive user transmitters in the present invention and the traditional scheme in a simulation experiment.

[0027] Figure 5 This is a comparison chart showing the impact of the number of cognitive user transmitters on the security interruption probability of authorized user transmitters in the present invention and the traditional scheme in a simulation experiment;

[0028] Figure 6 This is a comparison chart showing the impact of the channel parameter values ​​between the cognitive user transmitter and the eavesdropping user on the security interruption probability of the authorized user transmitter in the present invention and the traditional scheme, in a simulation experiment.

[0029] Figure 7 This is a comparison chart showing the impact of energy transfer efficiency values ​​on the probability of a safe interruption of the authorized user transmitter in the present invention and the traditional scheme, based on simulation experiments. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The cognitive wireless network uses a cognitive user power allocation method, which includes the following steps.

[0032] Please see Figure 1 First, the time segmentation ratio is determined, and based on this ratio, the communication time slots of the cognitive wireless network are divided into a pre-segment time slot and a post-segment time slot. Specifically, the time segmentation ratio is the ratio of the pre-segment time slot to the total communication time slot. T represents the total length of each communication time slot, and μ (0 ≤ μ ≤ 1) represents the time segmentation ratio. Therefore, the length of the pre-segment time slot is μ (0 ≤ μ ≤ 1), and the length of the post-segment time slot is μ (0 ≤ μ ≤ 1). After determining the lengths of the pre-segment and post-segment time slots according to the time segmentation ratio, the cognitive user receives pilot energy from the pilot signal transmitted by the licensed user in the pre-segment time slot and communicates using the pilot energy and its own initial energy in the post-segment time slot.

[0033] Cognitive users need to balance energy acquisition and information transmission, thus requiring the determination of an optimal time segmentation ratio to enable smooth communication while minimizing their initial energy consumption. To determine this optimal time segmentation ratio, this invention provides a method for doing so, as detailed below.

[0034] The method for determining the time segmentation ratio is as follows: Time segmentation ratio Where C c To understand the instantaneous capacity of the user receiver, and Where μ (0≤μ≤1) is the time division ratio, and T is the total length of the communication time slot. To understand the user's basic transmission rate, P is the channel coefficient between the cognitive user transmitter and the cognitive user receiver. A For authorized users' transmit power, h AR Let N0 be the channel coefficient between the authorized user's transmitter and the eavesdropping user, and N0 be the additive white Gaussian noise power. This method, starting from the cognitive user's reception performance, can improve the cognitive user's performance by determining the optimal time division ratio.

[0035] In other embodiments of the present invention, the time division ratio can also be determined based on the characteristics of the cognitive user receiver itself. Specifically, the signal-to-noise ratio of the cognitive user receiver is: Time segmentation ratio in Let P0 be the Lambertian W function, P0 be the basic transmit power of the cognitive user, and have E0 represents the initial energy of the cognitive user. This method determines the time division ratio based on the known signal-to-noise ratio of the cognitive user receiver, making it easier to implement.

[0036] Secondly, the cognitive user receives the pilot signal emitted by the authorized user in the preceding time slot and extracts pilot energy from the pilot signal. The pilot energy extracted by the cognitive user from the pilot signal is... Where η (0≤η≤1) is the energy transfer efficiency. The channel conditions between the licensed user transmitter and the cognitive user transmitter.

[0037] Finally, the cognitive user determines its actual transmission power based on the time division ratio, pilot energy, and its own initial energy. The cognitive user's actual transmission rate is... Where I represents the maximum tolerable interference level. To define the channel conditions between the cognitive user transmitter and the licensed user receiver, P0 represents the cognitive user's basic transmit power, and there are... E0 represents the initial energy for understanding users.

[0038] The cognitive user power allocation method for cognitive wireless networks of the present invention enables cognitive users to receive pilot signals transmitted by authorized users and obtain pilot energy from the pilot signals. Then, based on the pilot energy and their own initial energy, they can conduct secure communication, which can significantly improve the energy shortage problem of cognitive users, extend the service life of cognitive wireless networks, and balance the energy acquisition and information transmission of cognitive users by optimizing the time division ratio.

[0039] Based on the above-described cognitive user power allocation method, the present invention also provides a secure communication method for cognitive wireless networks, including S1 to S8.

[0040] Please see Figure 1 and 2 In this embodiment, the licensing system is based on the traditional underlay mode of cognitive wireless networks, introducing energy harvesting and a new transmission method. The licensing system includes licensed user transmitters (AT), licensed user receivers (AR), and several cognitive user transmitters (CT). i There is one cognitive user receiver CR and one eavesdropping user E. All terminals are simply configured with a single antenna and half-duplex mode. Furthermore, all the wireless communication channels and eavesdropping channels involved are quasi-static Rayleigh fading channels and additive white Gaussian noise channels. To simplify the analysis, it is assumed that all channel state information remains unchanged within one time slot, and h is known. A , h ARh AE , These represent channels AT→AR and AT→CT, respectively. i AT→CT n AT→CR, AT→E, CT i →AR, CT i →CR, CT i →E,CT n → Channel coefficients on E. Assume that the received noise of all receivers is additive white Gaussian noise with zero mean and power N0.

[0041] S1. Before transmitting information, the authorized user transmitter AT sends a message to the authorized user receiver AR and the cognitive user transmitter CT. i Send notification information.

[0042] S2. After receiving the notification information, the authorized user receiver AR broadcasts the pilot signal.

[0043] S3, Cognitive User Transmitter (CT) i Collect pilot signal energy from authorized user transmitters (AT) and determine the actual transmission power based on the power allocation method described above.

[0044] S4, Cognitive User Transmitter (CT) i Based on Authorized User Receiver (AR), Authorized User Transmitter (AT), and Cognitive User Transmitter (CT) i The communication status determines whether to add the candidate set M. l The specific methods for S4 are S4.1 to S4.3.

[0045] S4.1, Cognitive User Transmitter (CT) i Cognitive User Transmitter CT Based on Pilot Signal Calculation i Channel gain between licensed user receiver (AR) and AR

[0046] S4.2, Authorized user receiver AR calculates the received signal r A (t) and the corresponding instantaneous capacity C A :

[0047]

[0048]

[0049] Among them, h A For the channel coefficients between the licensed user transmitter AT and the licensed user receiver AR, s A (t) and s C (t) represent the authorized user transmitter AT and the cognitive user transmitter CT, respectively. iThe transmitted information, n A (t) represents the received noise on the licensed user receiver AR, and E[|s] A (t)| 2 ]=E[|s C (t)| 2 ] = 1, that is, for s A (t) and sC ( t) is normalized to simplify the analysis, and N0 is the power of additive white Gaussian noise.

[0050] S4.3, use R A This indicates the minimum transmission rate required by the authorized system to decode and recover the signal. When C A ≥R A At that time, the corresponding cognitive user transmitter CT i Select to add to the candidate set M l It can be represented as M l ={CT i , i∈(1,2,…,L)}, where L is the number of elements in the candidate set.

[0051] S5, Cognitive User Transmitter CT i The communication parameters between the authorized user receiver AR, the cognitive user receiver CR, and the eavesdropping user E are calculated and sent to the authorized user transmitter AT. The specific methods for S5 are S5.1 to S5.2.

[0052] S5.1, Cognitive User Transmitter (CT) i Calculate the received signal and instantaneous capacity of the authorized user receiver (AR), the cognitive user receiver (CR), and the eavesdropping user (E):

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] Where, r A (t) and C A These are the received signal and instantaneous capacity of the authorized user receiver AR, respectively. C (t) and C C These are the received signal and instantaneous capacity of the cognitive user receiver (CR), r E (t) and CE These are the received signal and instantaneous capacity of the eavesdropping user E, respectively, n C (t) and n E (t) represents the received noise on the cognitive user receiver CR and the eavesdropping user E, respectively. n (t) represents the cognitive user interference machine CT. n The transmitted information, and E[|s n (t)| 2 ] = 1, For cognitive user interference machine CT n As the transmit power when assisting cognitive users, and the cognitive user jammer CT n Because battery limitations and artificial noise transmitted can be canceled out by the cognitive user receiver's CR, h AE h is the channel coefficient between the authorized user transmitter AT and the eavesdropping user E. AR The channel coefficient between the authorized user transmitter AT and the eavesdropping user E. For cognitive user transmitter CT i The channel coefficients between the cognitive user receiver (CR) and the CR. For cognitive user interference machine CT n The channel coefficient between the eavesdropping user E, For cognitive user transmitter CT i The channel coefficient between the user E and the eavesdropping user.

[0060] because μ and T are known and well-defined, therefore the CT of each cognitive user transmitter under theoretical conditions can be directly calculated. i As a communication condition for assisting cognitive users, a more suitable cognitive user can be selected.

[0061] S5.2, Cognitive User Transmitter (CT) i r A (t), C A r C (t), C C r E (t) and C E Send to the authorized user's transmitter AT.

[0062] S6, Authorized User Transmitter AT from Alternate Set M l The cognitive user transmitter (CTi) with the best transmission performance is selected as the assisting communication user. The method for the licensed user transmitter (AT) to select the assisting communication user is as follows:

[0063] Indicates assistance to communication users, R CThis indicates the minimum transmission rate required for the cognitive system to decode and recover the signal.

[0064] S7, Authorized User Transmitter AT from Alternate Set M l Select a cognitive user transmitter (CT) with the best security performance. n As an assisting jamming user, the authorized user transmitter AT selects the assisting jamming user using the following method: This indicates assistance in interfering with the user.

[0065] S8, Authorized User Transmitter AT and Assisted Communication User and assisting in interfering with users Shared licensed frequency bands and assisting communication users Synchronous transmission of assist communication information with authorized user transmitters (AT) and assist in jamming users. Synchronized transmission assists with artificial noise. This assists communication users. Transmit cognitive user information to improve cognitive user transmission performance; assist interference users Transmitting artificial noise enhances the security performance of authorized users. In S8, the authorized user transmitter (AT) assists communication users. and assisting in interfering with users Transmit signals s separately on the licensed frequency bands A (t), s C (t) and s n (t), s n (t) is based on the authorized user transmitter AT and the assisting jamming user. The artificial noise designed according to the convention rules, and the recognition user receiver (CR) and authorized user receiver (AR) according to the convention rules, can effectively convert s n (t) is eliminated from the received signal, but this rule is unknown to the eavesdropping user E, therefore s n (t) will interfere with the eavesdropping user E, thereby improving the security of the communication process.

[0066] The present invention is theoretically verified below through connection interruption probability analysis and security interruption probability analysis.

[0067] In the first phase, in cognitive wireless networks, the cognitive user transmitter (CT) i Access to the licensed frequency band is only permitted if interference restrictions are met. Let the set be... The cognitive user transmitter CT represents the condition that satisfies the interference constraint. i The set consisting of M, where M i ={CT i |C A ≥R A, i∈{1,..,M}}, Cognitive User Transmitter (CT) on the licensed frequency band i There are two access scenarios: one is all cognitive user transmitters (CTs) i None of them satisfy the interference constraint conditions, that is This indicates that the CT transmitter is a user without cognition. i It can access licensed frequency bands; secondly, it is a cognitive user transmitter CT. i It meets the interference limiting conditions and has thus been connected to the licensed frequency band, that is Let all Rayleigh fading channel random variables |h A | 2 , |h AE | 2 , |h AR | 2 They respectively obey the parameters as If the distribution follows an exponential distribution, the probabilities of the two scenarios described above can be calculated as follows:

[0068]

[0069]

[0070]

[0071]

[0072] In the formula Ei(t) is an exponential integral function with independent variable t, that is, Where a is Euler's constant.

[0073] In the second phase, considering the cognitive user transmitters (CTs) accessing the licensed frequency band in the two scenarios of the first phase... i Different situations require different cognitive communication links (CT). i The probability of connection interruption on the CR, the probability of connection interruption on the authorized communication link AT→AR, and the probability of security interruption will all be different. Therefore, it is necessary to solve for the two interruption probabilities of the system in different cases. Let the cognitive communication link CT be... i →Connection interruption events on CR, connection interruption events on authorized communication link AT→AR, and their security interruption events respectively represent Ψ C Ψ A and Ψ int In case one, that is... Due to the lack of awareness of user transmitter CT i Access to authorized frequency bands, cognitive connection interruption probability The signals received by the authorized user receiver AR and the eavesdropping user E, and their corresponding instantaneous capacities, can be expressed as follows:

[0074]

[0075]

[0076] set up At this point, the probability of connection interruption and the probability of security interruption on the authorized communication link AT→AR are respectively...

[0077]

[0078]

[0079] The third stage, when hour, A cognitive user transmitter CT i It will be selected to assist cognitive users in accessing the licensed frequency band, and it has met the interference limitation condition C. A ≥R A Therefore, it is easy to derive the probability of connection interruption on the authorized communication link AT→AR in this situation. The second phase has already provided the received signals and instantaneous channel capacity on the authorized user receiver AR, the cognitive user receiver CR, and the eavesdropping user E under scenario two. Based on the two cooperative cognitive user selection models, let R... C This indicates the minimum transmission rate required for the cognitive receiver to decode and recover the signal. random variable U4=|h AR | 2 U5 = |h AE | 2 , Given W1 = U3 / U1 and W2 = U2 / U1, when selecting the best transmitter, the set M contains M elements. From the M cognitive user transmitters, L are selected as the candidate set M. l The elements in. And when selecting the optimal jammer, because... Therefore, the number of elements in set M is M-1 at this time. Let N = M-1, and select L from N cognitive user transmitters as the candidate set M. l The elements in the table. Then the connection interruption probability of cognitive users and the security interruption probability of authorized users can be solved as follows:

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086] In the formula, the probability density functions of W1 and W2 are:

[0087] The fourth phase, as described in the first phase, involves cognitive user transmitters (CTs). i There are two different possible scenarios for accessing the licensed frequency band, and in each scenario, the cognitive communication link (CT)... i The probability of connection interruption on the CR, the probability of connection interruption on the authorized communication link AT→AR, and the probability of security interruption have been obtained in the second and third phases. Therefore, according to Bayes' law of total probability, substituting the probabilities obtained in the first, second, and third phases into the law of total probability, the probability of connection interruption on the complete authorized communication link AT→AR and the probability of security interruption on the cognitive communication link CT in the transmission mode of this invention are obtained. i The probability of connection interruption on →CR and the probability of security interruption on the authorized communication link AT→AR can be solved.

[0088]

[0089]

[0090]

[0091] In the above formula The probability can be obtained by substituting the values.

[0092] The invention is verified through simulation experiments.

[0093] Depend on Figure 3 and 4 It can be seen that when the system recognizes the user's transmitter CT i When the number M is the same, this invention outperforms the connection interruption performance on the authorized communication link AT→AR in traditional networks. Furthermore, under the same scheme, the probability of connection interruption on the authorized communication link AT→AR decreases significantly as the value of M increases. When M has the same value, the cognitive communication link CT in this invention... i →The probability of connection interruption on CR is significantly lower than that on traditional networks, while in the same method, as the value of M increases, the cognitive communication link CT i →The probability of connection interruption on the CR will also be significantly reduced. In summary, the cognitive communication link CT in this invention i →CR and authorized communication link AT→AR connection interruption performance is no worse than traditional networks, especially in cognitive communication link CT under conditions of a large number of cognitive users. i→ The connection interruption performance on CR is significantly better than that on traditional networks.

[0094] Depend on Figure 5 , 6 As can be seen from 7, when the system recognizes the user transmitter CT i The number M or channel parameters Alternatively, when the energy transfer efficiency η has the same value, this invention outperforms the security interruption performance on the authorized communication link AT→AR in traditional networks. Furthermore, under the same scheme, the performance varies with the value of M or the channel parameters. Increasing the value of η, or the energy transfer efficiency η, will reduce the probability of security interruption on the authorized communication link AT→AR. In summary, the security interruption performance of the authorized communication link AT→AR under the model of this invention is superior to that of traditional networks, meaning that this invention improves the transmission security performance of authorized users.

[0095] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A secure communication method for cognitive wireless networks, characterized in that, Includes the following steps: S1. Before transmitting information, the authorized user transmitter sends a notification message to the authorized user receiver and the cognitive user transmitter. S2. After receiving the notification information, the authorized user receiver broadcasts a pilot signal. S3. The cognitive user transmitter collects the pilot signal energy from the licensed user transmitter and determines the actual transmitted power; The method for a cognitive user transmitter to determine the actual transmission power is as follows: Determine the time segmentation ratio, which is the ratio of the pre-segment time slot to the communication time slot, and divide the communication time slot of the cognitive wireless network into pre-segment time slots and post-segment time slots based on the time segmentation ratio; The cognitive user receives the pilot signal emitted by the authorized user in the preceding time slot and extracts pilot energy from the pilot signal. The pilot energy extracted by the cognitive user from the pilot signal is... ,in For energy transfer efficiency. Channel conditions between the licensed user transmitter and the cognitive user transmitter; The cognitive user determines its actual transmission power based on the time division ratio, pilot energy, and its own initial energy. The cognitive user's actual transmission power is... ,in For the maximum tolerable level of interference, To understand the channel conditions between the user transmitter and the licensed user receiver, To understand the user's basic transmit power, and have , To cultivate the initial energy of users; The first method for determining the time segmentation ratio is: Time segmentation ratio ,in To understand the instantaneous capacity of the user receiver, and ,in The time segmentation ratio, The total length of the communication time slot. To understand the user's actual transmission rate, For the channel coefficients between the cognitive user transmitter and the cognitive user receiver, For authorized users' transmit power, The channel coefficient between the authorized user's transmitter and the eavesdropping user. This represents the power of additive white Gaussian noise. The second method for determining the time segmentation ratio is as follows: The signal-to-noise ratio of the cognitive user receiver is Time segmentation ratio ,in , , For the Lambert W function, To understand the user's basic transmit power, and have , To cultivate the initial energy of users; S4. The cognitive user transmitter selects whether to join the candidate set based on the communication status between the authorized user receiver and the authorized user transmitter and the cognitive user transmitter; the specific method of S4 is S4.1 to S4.3; S4.1, Cognitive User Transmitter Cognitive User Transmitter Based on Pilot Signal Calculation With authorized user receiver Channel gain between ; S4.2, Authorized User Receiver Calculate the received signal and the corresponding instantaneous capacity : in, For authorized user transmitters With authorized user receiver Channel coefficients between and These represent authorized user launches. Machine and cognitive user transmitter The information transmitted For authorized user receivers The received noise on the surface, for and Normalization is performed, and there are To simplify the analysis, This represents the power of additive white Gaussian noise. S4.3, use This indicates the minimum transmission rate required by the authorized system to decode and recover the signal. At that time, the corresponding cognitive user transmitter Select to add to the candidate set , represented as , The number of elements in the candidate set; S5. The cognitive user transmitter calculates the communication parameters between the authorized user receiver, the cognitive user receiver, and the eavesdropping user, and sends them to the authorized user transmitter; the specific method of S5 is S5.1 to S5.

2. S5.1, Cognitive User Transmitter Computational Authorized User Receiver Cognitive User Receiver and eavesdropping users Received signal and instantaneous capacity: in, and These are authorized user receivers The received signal and instantaneous capacity, and These are cognitive user receivers The received signal and instantaneous capacity, and These are eavesdropping users The received signal and instantaneous capacity, and Cognitive user receiver and eavesdropping users Received noise on Represents cognitive user interference machine The information transmitted, and , For cognitive user interference machine Transmit power used to assist cognitive users, and cognitive user jammer Due to battery limitations and artificial noise emitted, cognitive user receivers... To offset, therefore , For authorized user transmitters With eavesdropping users Channel coefficients between For authorized user transmitters With eavesdropping users Channel coefficients between For cognitive user transmitter With cognitive user receiver Channel coefficients between For cognitive user interference machine With eavesdropping users Channel coefficients between For cognitive user transmitter With eavesdropping users Channel coefficients between; S5.2, Cognitive User Transmitter Will , , , , and Send to authorized user transmitter ; S6. The authorized user transmitter selects a cognitive user transmitter with the best transmission performance from the candidate set as the assisting communication user; authorized user transmitter The method for selecting a user to assist with communication is as follows: , This indicates assistance to communication users. This indicates the minimum transmission rate required for the cognitive system to decode and recover the signal; S7. The authorized user transmitter selects a cognitive user transmitter with the best security performance from the candidate set as the assisting jammer; Authorized user transmitter The method chosen to assist in interfering with users is: , This indicates an assisting interference user; S8, the authorized user transmitter shares the authorized frequency band with the assisting communication user and the assisting interference user, and the assisting communication user transmits assisting communication information synchronously with the authorized user transmitter, and the assisting interference user transmits assisting artificial noise synchronously.

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