CN114793127B - Dual-function radar communication method, device, computer equipment and storage medium - Google Patents
Dual-function radar communication method, device, computer equipment and storage medium Download PDFInfo
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Abstract
The invention discloses a difunctional radar communication method, a device, computer equipment and a storage medium, which comprises the following steps: a multi-antenna base station adopts a uniform linear antenna array (ULA) to transmit signals to a plurality of single-antenna users on a downlink, and simultaneously adopts a special ULA to receive radar signals at a receiving end; the base station side collects the statistical knowledge of the channel state information and constructs the problem of minimum transmission total power by meeting the service quality constraint of the communication and radar parts; giving a precoding matrix standard orthogonalization constraint to maximize radar output signal-to-noise ratio to obtain an optimal radar receiving beamforming matrix; giving a receiving beam forming matrix, simplifying a power minimization problem into a semi-definite programming problem by using a rank-one method, and solving an optimal precoding matrix by using an interior point method; the optimal precoding matrix is further modified by power control to meet communication and radar sensing requirements. The communication method effectively reduces the design complexity of the radar communication system and ensures the power consumption requirement.
Description
Technical Field
The present invention relates to the field of wireless communications technologies, and in particular, to a method and apparatus for dual-function radar communication, a computer device, and a storage medium.
Background
Fifth generation (5G) and dual-function radar communication are urgent in demands for low design complexity, low power consumption, high reliability and the like. Fifth generation (5G) and later wireless technologies must meet the exponentially growing demands for high quality wireless communication services that wireless communication systems can benefit from additional spectrum resources to meet. Among the various schemes, the problem of joint communication-radar spectrum sharing has attracted a great deal of attention in recent years.
The goal of the DFRC system is to design an operating system that can jointly handle radar and communication systems. This design can be applied to real-time joint sensing/communication operations through a single hardware setup, which requires less hardware complexity, implementation cost, and communication overhead. The DFRC system is implemented by designing the transmit waveforms such that both radar and communication related performance metrics are optimized by space/time constraints. By adopting the method, the space freedom degree of the DFRC system, namely the multi-transmitting antenna, can be effectively utilized. For such multiple-input multiple-output (MIMO) systems, the transmit waveforms are designed to enable high information transmission rates to the target users and reliable operation of the radar system. The linear precoding matrix is decomposed into two parts, one for communication and one for radar systems. The focus of the current work is also the development of linear precoding solutions in DFRC systems. In the previous work, a linear precoder for DFRC systems was designed in order to optimize the performance of the radar system under the constraint of maintaining a certain predefined quality of service (QoS) for the communication users and the transmission power. On the other hand, such a dual-function radar communication system has two different objectives to be optimized, one for the radar and one for the communication part, typically providing different design options, tailored to a specific scene. For example, an application may require a minimum QoS for target detection performance. Therefore, a design that aims to optimize the performance of the communication section as much as possible is more appropriate under the constraints of the QoS of the radar section described above. In addition, the concept of the internet of things relates to low power consumption systems, such as sensors and the like. In the latter case, it is more interesting to have a DFRC system whose aim is to minimize the total transmit power while maintaining the ideal QoS in the radar and communication parts.
Disclosure of Invention
The invention aims to solve the urgent demands of mission-critical dual-function radar communication in the prior art on low design complexity, low power consumption, high reliability and the like, and provides a dual-function radar communication method, a device, computer equipment and a storage medium. The invention achieves the aims of low power consumption and low design complexity by combining the precoding technology and the beam forming technology. The invention minimizes the total power transmitted by optimally designing the optimal precoding matrix and meeting the quality of service constraints of the communication and radar parts. In consideration of the characteristics of low power consumption, limited computing resources and the like in the dual-function radar communication, the power minimization problem is simplified into a semi-definite programming problem to be solved by utilizing a rank one method. Finally, the optimal precoding matrix is further modified by power control to meet communication and radar sensing requirements.
The first object of the present invention is to provide a dual-function radar communication method, which comprises the following implementation steps:
s1, in a dual-function radar communication system, a multi-antenna base station adopts a uniform linear antenna array on a downlink to send signals to a plurality of single-antenna user terminals, and meanwhile, a receiving end adopts a uniform linear antenna array to receive and transmit radar detection waveforms and detect point targets at the same time, wherein the dual-function radar communication is hereinafter referred to as DFRC, the uniform linear antenna array is hereinafter referred to as ULA, the base station is hereinafter referred to as BS, and the user terminals are hereinafter referred to as UT;
S2, the base station collects the statistical knowledge of the channel state information, and constructs the problem of total transmission power minimization by meeting the service quality constraint of the communication and radar parts, namely
s.t.ξ m (W)≥η m ,1≤m≤M,
γ(W,c)≥η,
Where W is a T×M complex linear precoding matrix, c is a linear R×1 receive beamforming vector,andthreshold values related to communication and radar quality of service, respectively,/->Representing a positive real number, T representing the number of elements transmitting ULA, R represents the number of elements that receive the ULA, M represents the total number of user terminals, I.I F Representing the Frobenius matrix norm, ζ m (W) represents the received signal-to-interference-and-noise ratio of the mth UT, expressed as +.>Wherein the signal-to-interference-plus-noise ratio is hereinafter referred to as SINR, (-) H Self-co-ordinating representing vectors/matricesYoke matrix, w m And w k Is the m-th column and the k-th column of the matrix W,>and->Respectively represent w m And w k Is a self-conjugate matrix of h m Represents the mth column of matrix H, +.>Represents h m Self-conjugate matrix of>Represents the noise variance of the vector z, z is an Mx1 additive Gaussian white noise vector, and γ (W, c) represents the output SINR of the radar beamforming, expressed as +.>Wherein->And->Representing the complex amplitudes of the target and the kth interferer, c H Is the self-conjugate matrix of vector c, W H Is the self-conjugate matrix of matrix W, +.>Represents the noise variance of the vector u, which represents the circularly symmetric complex Gaussian white noise vector, θ 0 And theta k Representing the angles of the target and the kth interference source in the azimuth, A (theta 0 ) And A (theta) k ) Positive definite matrix representing the azimuth angles of the target and the kth interference source respectively, A H (θ 0 ) And A H (θ k ) Respectively represent A (theta) 0 ) And A (theta) k ) Self-conjugate matrix of>a r (θ) is the R1 vector of propagation delays from the source at angle θ to the radar receiving element, (-) T Representing a transpose of the vector/matrix expressed asIs a t Transpose of (θ), a t (θ) represents a T×1 emission steering vector expressed as
S3, giving an optimal value W of the precoding matrix * Optimizing radar receive beamforming matrix c by maximizing radar output SINR * The optimization problem is as follows:
s4, the optimal radar beam forming matrix c * Substitution intoIn (1) rank one method is adopted>The reduction of the power minimization problem to the semi-definite programming SDP problem is as follows
X m ≥0,
Wherein X is m Rank 1, tr (·) represents the trace of the matrix,w j is the j-th column of the matrix W, +.>Is w j Self-conjugate matrix of>And is also provided with(c * ) H Is c * Self-conjugate matrix of>And->Represents the target and the kth modified optimal radar beamforming matrix, respectively,/for each radar beam>And->Are respectively->And->Solving the optimization problem by an interior point method, and if the rank one is not satisfied, finding the problem by Gaussian randomization >Is a solution to the approximation of (a),for each precoding vector w m L candidate vectors generated, i.e.>Wherein U is m And->Respectively a matrix consisting of eigenvectors and a diagonal matrix,>representing variance as unit matrix I T Complex gaussian matrix of (a), matrix U m Sum sigma m Calculating and decomposing the optimal matrix from the eigenvalues>I.e. < ->Generating candidate vectors such thatRepresenting a desired operator;
s5, further correcting the optimal precoding matrix through power control to meet communication and radar sensing requirements, and constructing an optimization problem
p m ≥0,
Wherein,,is the square value of the European norm of the precoding matrix,>and->Respectively representing the mth precoding vector parameter corrected by the mth channel matrix and the jth precoding vector parameter corrected by the mth channel matrix,/>And->Respectively w m And w j W is a self-conjugate matrix of m And w j Respectively denoted as mth candidate vector and jth candidate vector, gamma m,m And gamma k,m Representing the output SINR received at the mth UT interfered by the mth interferer and the output SINR received at the mth UT interfered by the kth interferer, respectively,>scaling parameters for the mth and jth precoding vectors, respectively,/for the mth and jth precoding vectors>Representing real numbers, problem->For linear programming with M non-negative variables and M+1 linear inequality constraints, solving the problem by the interior point method +. >
Further, two other optimization problems can be constructed by the control variable method in the step S2 as follows: if the robustness of the signal-to-interference-and-noise ratio is set under the constraint of the total transmitting powerAnd (3) calculating, ensuring the service quality of the radar and constructing the optimization problem:
wherein P is max Is the maximum transmitting power supported by the DFRC system, and the constant weight is 1/eta m Different service levels between UTs are illustrated;
if the signal-to-interference-and-noise ratio performance of the radar is maximized, the total transmitting power is limited and the communication service quality is guaranteed, and the optimization problem is constructed as follows:
further, in the step S3, when the radar receiving beamforming matrix is optimized, in order to obtain the analysis result of the optimal radar receiving beamforming matrix, assume W * (W * ) H =I T Further converting the optimization problem into
The optimal radar receiving beam forming matrix corresponding to the optimization problem is as follows
A second object of the present invention is to provide a dual function radar communication method apparatus including:
the signal receiving and transmitting module is used for introducing a receiving uniform linear antenna array, namely receiving the uniform linear antenna array is called ULA (ultra low power) for short, a base station at a transmitting end in the dual-function radar communication system transmits signals to a plurality of single-antenna users through the ULA, and meanwhile, a receiving end receives radar signals by adopting a special ULA;
A total power minimization construction module for collecting statistical knowledge of channel state information at the base station end, and constructing transmission total power minimization problem by satisfying service quality constraint of communication and radar parts, namelyWherein W is a T×M complex linear precoding matrix and c is a linear Rx1 receive beamforming vector,/I>And->Threshold values related to communication and radar quality of service, respectively,/->Representing a positive real number, T representing the number of elements transmitting ULA, R represents the number of elements that receive the ULA, M represents the total number of user terminals, I.I F Representing the Frobenius matrix norm, ζ m (W) represents the received signal-to-interference-and-noise ratio of the mth UT, expressed as +.>Wherein the signal-to-interference-plus-noise ratio is hereinafter referred to as SINR, (-) H Self-conjugate matrix representing vector/matrix, w m And w k Is the m-th column and the k-th column of the matrix W,>and->Respectively represent w m And w k Is a self-conjugate matrix of h m Represents the mth column of matrix H, +.>Represents h m Self-conjugate matrix of>Represents the noise variance of the vector z, z is an Mx1 additive Gaussian white noise vector, and γ (W, c) represents the output SINR of the radar beamforming, expressed as +.>Wherein->And->Representing the complex amplitudes of the target and the kth interferer, c H Is the self-conjugate matrix of vector c, W H Is the self-conjugate matrix of matrix W, +. >Represents the noise variance of the vector u, which represents the circularly symmetric complex Gaussian white noise vector, θ 0 And theta k Representing the angles of the target and the kth interference source in the azimuth, A (theta 0 ) And A (theta) k ) Positive definite matrix representing the azimuth angles of the target and the kth interference source respectively, A H (θ 0 ) And A H (θ k ) Respectively represent A (theta) 0 ) And A (theta) k ) Self-conjugate matrix of>a r (θ) is the R1 vector of propagation delays from the source at angle θ to the radar receiving element, (-) T Representing a transpose of the vector/matrix expressed asIs a t Transpose of (θ), a t (θ) represents a T×1 emission steering vector expressed as
A beam forming module for giving the optimal value W of the precoding matrix * Optimizing radar receive beamforming matrix c by maximizing radar output SINR * The optimization problem is as follows:
a pre-coding module for forming the optimal radar beam forming matrix c * Substitution intoIn (1) rank one method is adopted>The reduction of the power minimization problem to the semi-definite programming SDP problem is as follows
X m ≥0,
Wherein X is m Rank 1, tr (·) represents the trace of the matrix,w j is the j-th column of the matrix W, +.>Is w j Self-conjugate matrix of>And is also provided with(c * ) H Is c * Self-conjugate matrix of>And->Represents the target and the kth modified optimal radar beamforming matrix, respectively,/for each radar beam >And->Are respectively->And->Solving the optimization problem by an interior point method, and if the rank one is not satisfied, finding the problem by Gaussian randomization>For each precoding vector w m L candidate vectors generated, i.e.>Wherein U is m And->Respectively a matrix consisting of eigenvectors and a diagonal matrix,>representing variance as unit matrix I T Complex gaussian matrix of (a), matrix U m Sum sigma m By characteristics ofValue calculation decomposition optimal matrix +.>I.e. < ->Generating candidate vectors such thatRepresenting a desired operator;
the power control module is used for further correcting the optimal precoding matrix through power control to meet communication and radar sensing requirements, and the optimization problem is constructed
p m ≥0,
Wherein,,is the square value of the European norm of the precoding matrix,>and->Respectively representing the mth precoding vector parameter corrected by the mth channel matrix and the jth precoding vector parameter corrected by the mth channel matrix,/>And->Respectively w m And w j W is a self-conjugate matrix of m And w j Respectively denoted as mth candidate vector and jth candidate vector, gamma m,m And gamma k,m Representing the output SINR received at the mth UT interfered by the mth interferer and the output SINR received at the mth UT interfered by the kth interferer, respectively, >Scaling parameters for the mth and jth precoding vectors, respectively,/for the mth and jth precoding vectors>Representing real numbers, problem->For linear programming with M non-negative variables and M+1 linear inequality constraints, solving the problem by the interior point method +.>
A third object of the present invention is to provide a computer device including a processor and a memory for storing a program executable by the processor, wherein the processor implements the above-mentioned dual function radar communication method when executing the program stored by the memory.
A fourth object of the present invention is to provide a storage medium storing a program which, when executed by a processor, implements the above-described dual function radar communication method.
Compared with the prior art, the invention has the following advantages and effects:
1. one object of the present invention to design a dual function radar communication system is to minimize the total power of its transmissions under the constraints of the received SINR at the user and the radar output SINR, which is solved for the first time in the present invention.
2. Another object of the present invention to design a dual function radar communication system that optimizes the performance of the communication part by maximizing the minimum received SINR between users constrained by the total transmitted power and radar output SINR. This problem is also solved for the first time in the present invention.
3. The invention simplifies the optimal design of the dual-function radar communication system by utilizing the pre-coding technology and the beam forming technology, effectively reduces the design complexity of the system and ensures the power consumption requirement.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of an implementation of the dual function radar based communication method in embodiment 1 of the present invention;
FIG. 2 is a schematic diagram of a system model based on a dual function radar communication method in embodiment 1 of the present invention;
FIG. 3 is a graph of total transmit power minimization versus noise variance for a communication system under different communication and radar QoS constraints in accordance with embodiment 1 of the present invention;
fig. 4 is a block diagram showing the configuration of a dual function radar communication device in embodiment 2 of the present invention;
fig. 5 is a block diagram showing the structure of a computer device in embodiment 3 of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1:
for the convenience of description of the present embodiment, the following symbols are first defined: bold uppercase and lowercase letters are used to represent matrices and vectors, respectively; i N Representing an n×n identity matrix; 0 N A zero identity matrix representing n×n;and->Domains representing complex, real and positive real numbers, respectively; the |·| represents the modulus of the complex number; />Representing a desired operator; I.I F Representing the Frobenius norm; (. Cndot. H And ( T Representing the self-conjugate matrix and transpose of the vector/matrix, respectively; tr (·) and rank (·) represent the trace and rank, respectively, of the matrix; a is more than or equal to 0 and is expressed as a positive definite matrix A; CN (·, ·) represents a complex circularly symmetric gaussian distribution;
system model and performance index
The present invention contemplates a dual function radar communication system (fig. 1) employing a uniform linear antenna array (ULA) of T elements with a half wavelength element spacing on the transmitter side. The DFRC system is intended to serve M single antenna users in downlink operation, while at the receiving end the DFRC system is also equipped with a dedicated ULA of R elements for receiving radar signals, following a radar system model with collocated transmit and receive antenna arrays.
For simplicity, by deleting the time index, the signal received at the communication user of a single time slot is given by: y= HWs +z (1)
Wherein the method comprises the steps ofIs a vector whose entry y m Is the signal received at the mth user, W is the T×M complex lineThe linear precoding matrix is updated based on the channel coherence time, s is a complex M x 1 vector, its entry s m Is the symbol sent to the mth user, drawn by a known constellation, T represents the number of elements of the transmitted ULA, R represents the number of elements of the received ULA, M represents the total number of user terminals,/user terminals>Is a matrix of frequency flat fading channels between DFRC system and users, z is an Additive White Gaussian Noise (AWGN) complex vector variable of mx 1, corrupting the corresponding transmission,/- >Representing the noise variance of z.
From the perspective of the communication system, the performance index available to design the system is the received signal to interference and noise ratio (SINR) for each user, given by:
wherein ( H Self-conjugate matrix representing vector/matrix, w m And w k Is the m-th and k-th columns of the matrix W,andrespectively represent w m And w k Is a self-conjugate matrix of h m Represents the mth column of matrix H, +.>Represents h m And in the self-conjugate matrix ofAnd->The expression in (2) is deduced in the case of (2), whereins H And z H Representing the self-conjugate matrix of s and z, respectively, I M And 0 (0) M Representing an M x M identity matrix and an M x M zero identity matrix. Because the received SINR of each user is related to its achievable rate, r m =log 2 (1+ξ m (W)) (3)
The DFRC system transmits a tx 1 signal at each slot, which is constructed by linear precoding of the desired symbol, and transmits the signal to the user, i.e., W s . For simplicity, the time index is deleted again. For this transmitted signal, the signal seen at the position of angle θ is given by,
a t (θ)W s (4) Wherein a is t And (θ) represents a tx 1 transmit steering vector. Here, it is assumed that ULA with half wavelength element pitch is used. Thus, the emission steering vector is given by,
assuming that the target is at an angle theta 0 . In addition, there are K signal-dependent interferers located at angle θ k ≠θ 0 K=1, …, K. The baseband signal vector of the radar receiving array during the symbol time is given by,
wherein ( T Representing the transpose of the vector/matrix, alpha 0 And alpha k The complex amplitudes of the target and kth interferer respectively,u is the mean value of the circularly symmetric complex Gaussian white noise vector is zero and the covariance matrix is equal toIs the noise variance of u, θ 0 And theta k Representing the direction in which the target and the kth source of interference are located, respectivelyAngle (S)>Is a t Self-conjugate matrix of (θ), +.>Is a r (θ), a r (θ) is an r×1 vector of propagation delays from a source located at an angle θ to a radar receiving element. Also, under the assumption of ULA with half-wavelength spacing between adjacent elements, i.e
By defining A (θ) of the angle θ as
The writing of (6) is as follows
Wherein A (θ) 0 ) And A (theta) k ) Representing the positive definite matrix of the azimuth angles of the target and the kth interference source respectively.
From the perspective of radar systems, one common approach to designing radar waveforms is based on output signal-to-noise metrics. The detection probability is typically a monotonically increasing function of the output SINR assuming that a linear rx 1 receive beamforming vector c is applied across the radar receiving array to maximize the output signal-to-noise ratio. The output signal after the beamforming vector is applied is,
Wherein c H Is the self-conjugate matrix of vector c, beta k Is after correctionFor this signal model, the output SINR can be expressed as the complex amplitude of the kth interferer
Wherein the method comprises the steps ofAnd->Representing the complex amplitudes of the target and the kth source, W H Is a self-conjugate matrix of matrix W, A H (θ 0 ) And A H (θ k ) Respectively represent A (theta) 0 ) And A (theta) k ) Is self-conjugate matrix of (1), assuming->And is also provided withRepresents I M Representing an m×m identity matrix; 0 R Representing the zero identity matrix of R x R.
(II) description of problem
The present invention proposes three different and novel approaches that look at DFRC systems from three different angles, resulting in three different problem expressions: 1) a total transmission power constrained by communication and radar QoS, 2) a minimum received SINR at users constrained by radar QoS and total transmission power, and 3) a maximum radar received SINR constrained by communication QoS and total transmission power. The core idea behind the following approach is to focus on optimizing one part/metric of the DFRC system at a time while meeting the minimum QoS requirements of the other part/metric to produce an easy-to-process formula.
Furthermore, the derivation of the precoding matrix and beamforming matrix requires knowledge of the channel matrix H and radar parameters θ k Andfor k=0, 1, …, K. The estimation methods employed by the independent communication and radar systems may also be employed by the DFRC system. That is, the channel matrix may be estimated by a training-based scheme. The radar parameters may be estimated by using an environmental dynamics database, following a cognitive radar paradigm.
In this approach, the goal is to minimize the total power transmitted by the system while maintaining the minimum QoS for the communication and radar parts. This is achieved by keeping the received SINR and radar output SINR of the user above a predefined threshold associated with the target QoS. Thus, the optimization problem of deriving optimal W and c is defined asWherein->And->Threshold values related to communication and radar QoS, respectively,/-for>Represents a positive real number and, I.I F Representing the Frobenius matrix norm. Problem->Is a quadratic programming with non-convex constraint (qqp) problem.
In this approach, the goal is to optimize the performance of the communication part by following the max-min SINR approach, while maintaining the minimum QoS of the radar part and meeting the constraints on the total power transmitted. Thus, the optimal W and c can be deduced as solutionsWherein P is max Is the maximum transmit power supported by the DFRC system and is constant weighted 1/η m Different service levels between users are illustrated. Due to the non-convexity sum of the cost functionsNon-convex constraint of radar part QoS, +.>The problem is non-convex.
In a third approach, the DFRC system designs the W and c variables to optimize the performance of the radar section by maximizing its output SINR while maintaining minimum QoS for the serving user and meeting the constraints on the total power transmitted. In this case, the optimization problem to be solved is defined as
s.t.ξ m (W)≥η m
Since the objective function and the constraint on the SINR of the user are non-convex, theAnd is also a non-convex optimization problem.
(III) solution
In this section, deriveIs a solution to (a). In general, joint optimization of the precoding matrix W and the radar receive beamforming matrix c is a very difficult task, as these two variables are coupled by the radar output SINR expression. Therefore, to simplify the problem->Consider a method of decoupling this transmit-receive design problem.
From the slaveCan be defined directly byIt is seen that the beamforming matrix c only appears in the radar output SINR expression. Thus, its optimization will only involve this performance index. Assume the optimal value W of the precoding matrix * Are known. Method for deriving optimal radar reception beamforming matrix by maximizing radar output SINR, i.e
Such a selection corresponds toI.e. to maximize the radar system received SINR. Furthermore, it may only increase +.>And->Due to the performance of the radar part of (c) * ,W * )≥γ(c,W * ) And c * Is taken as->Is used for solving the derived optimal radar receiving beamforming matrix.
Even if calculate c * As just discussed, by solving forIs an optimization question of all examined->This is not a simple task. This is so because of +.>The solution of (a) requires knowledge of the optimal precoding matrix W * . Generally, due to the radar transmission and reception in questionThe coupling between the problems, the latter cannot be deduced under the assumption of an unknown radar beamforming matrix. To circumvent this, observe that in case the optimal precoding matrix is an orthogonal matrix, i.e. W * (W * ) H =I T The optimal receive beamforming matrix c may be obtained by first deriving it * To decouple radar transmission and reception problems.
Then, by replacing c with c * At the position ofW * Can be derived by solving the decoupling problem, defined in broad terms as: />
Wherein f (W) represents based onCost function with minimized or maximized considered problem, +.>Is a related set of constraints. Now, since the orthogonal constraint is a very strict and non-convex constraint, this will further plague the problem of being already very difficult +. >And therefore discarded in the subsequent derivation. Relaxation problem with->And (3) representing.In the question->In (a) a feasible solution must exist in the set +.>And an intersection of complex T x M matrices with orthonormal properties. This set is denoted asFurthermore, when the orthogonality constraint is discarded, one possible solution has to be in the set +.>Is a kind of medium. Can be easily seenThe former in fact means if the question +.>There is an optimal solution to the precoding matrix W with orthogonal properties, which also exists in the feasible solution set +.>In, therefore, it is also +.>Is a solution to the optimization of (3). Otherwise, if->Does not have orthogonal properties, it generally corresponds to a solution of +.>The optimal target value is better than the solution forced orthogonal structure. In other words, by giving up the orthogonal constraint, there is no negative impact on performance, since +.>Is +.>Lower limit of (2).
Before continuing to derive the solution for each of the three inspection cases, it is still necessary to deriveIs a solution to (a). By examining this unconstrained optimization problem, it can be seen that it can be converted into a generalized eigenvalue problem that accepts a closed form solution given by
C after changing the optimal radar beam forming matrix * The optimal precoding matrix W can be derived by solving the result problem and is defined asWherein->(c * ) H Is c * Self-conjugate matrix of>And->Represents the target and the kth modified optimal radar beamforming matrix, respectively,/for each radar beam>And->Are respectively->And->Is a self-conjugate matrix of (a). The resulting equivalent optimization problem is given by
X m ≥0,rank(X m )=1,1≤m≤M.
Wherein the method comprises the steps ofIs the j-th column of the matrix W, +.>Is w j Self-conjugate matrix of>tr (·) and rank (·) represent the trace and rank, respectively, of the matrix. Removing M non-convex rank constraint to obtain ∈K>The following loose version of (c):
X m ≥0,1≤m≤M.
problem(s)Is composed of a linear objective function, M+1 linear inequality constraints and M positive semi-definite constraints. Thus, this is a semi-definite programming (SDP) problem that can be effectively solved by the interior point method. In the question->In case of acceptable solution +.>And also acceptable for solution. However, since it is a loose version, it does not necessarily acknowledge the first-level solution. For this purpose, the problem can be found by means of the Gaussian randomization technique>Is a solution to the approximation of (a). For each precoding vector w, according to the following method m L candidate vectors generated, i.e.>Wherein U is m And->Respectively a matrix consisting of eigenvectors and a diagonal matrix, >Representative ofVariance is unit matrix I T Complex gaussian matrix of (a), matrix U m Sum sigma m Calculating and decomposing the optimal matrix from the eigenvalues>I.e. < ->Generating candidate vectors such that->Representing the desired operator.
One problem with candidate vectors is that, in general, they do not meet communication and radar constraints. Therefore, they should be scaled up to be in the feasible solution set. This can be done by solving the defined power control problem
p m ≥0,1≤m≤M,
Wherein,,is the square value of the European norm of the precoding matrix,>andrespectively represent the sum of the mth precoding vector parameters corrected by the mth channel matrixThe j-th precoding vector parameter corrected by the m-th channel matrix,/th precoding vector parameter corrected by the m-th channel matrix>And->Respectively w m And w j W is a self-conjugate matrix of m And w j Respectively denoted as mth candidate vector and jth candidate vector,/>Scaling parameters for the mth and jth precoding vectors, respectively,/for the mth and jth precoding vectors>Representing real number,/->For the mth precoding vector parameter corrected by the kth positive definite matrix,is A (theta) k ) Is a positive matrix of candidates. Utilization problem->The fact that the denominator in the constraint expression is positive can be converted into an equivalent form given by the following formula
p m ≥0,1≤m≤M.
Wherein gamma is m,m And gamma k,m Respectively representing the output SINR received at the mth UT interfered by the mth interference source and the output SINR received at the mth UT interfered by the kth interference source, a problem Is a linear program with M non-negative variables and m+1 linear inequality constraints. This problem can be effectively solved by the interior point method. Suppose a feasible solution is found for the first candidate vector>1.ltoreq.m.ltoreq.m, then for all 1.ltoreq.m.ltoreq.m, the latter is scaled to +.>And selecting the precoding vector with the smallest total power from the L candidate vectors as a column of a precoding matrix w. The overall computational complexity is determined by the SDP problem>And L linear programming. The former needs +.>And the latter->And (5) arithmetic operation.
The precoding matrix w may then be derived by solving the modification problem given by the following equation,
inequality constraints will be satisfied under the optimal equation. If this is not the case and the power budget is left, the remaining power can be evenly distributed among the users, i.e. the precoding vector is scaled by a constant strictly greater than one. This will also increase all SINR for all users and radar systems. The latter contradicts optimality assumptions. By using auxiliary positive variablesCan be converted into equivalent form
Wherein,,and->Optimum values of parameter correlations of (a). In a similar manner letUse->Is indicative of the associated minimum power. By following a procedure similar to the above, the problem +. >And->The correlation of (2) is as follows:
can be deducedP max Can solve by iteration +.>For different t values. Furthermore, the question can be proven->And->Is monotonically non-increasing for a given weight eta M M is more than or equal to 1 and less than or equal to M, t and P max Is reduced. Thus, the optimal t value can be found by one-dimensional bisection.
By using transformationsWherein X is m ≥0,rank(X m ) =1 and 1.ltoreq.m.ltoreq.M is +.>And by deleting rank-1 constraints, as if it were about the problem->As in the case of (2), the following problem of scaling results is obtained
X m ≥0,t≥0,1≤m≤M,
In addition, it is also possible to deduceAnd->Is monotonic for a given weight eta m M is more than or equal to 1 and less than or equal to M, t and P max Neither is reduced.
Can be solved by one-dimensional bisection on t such that +.>The dichotomy requires a closed interval t l ,t u ]Wherein the best t is located therein. The lower observation limit may be set to t l =0, because t.gtoreq.0 and the upper limit is set to +.>And assuming that all available power is allocated to a single user.
Due to solving ofA relaxed version of (a) and thus the matrix X obtained * m May be higher than 1. Therefore, the application here also has to be adapted to +.>Is a gaussian randomization technique of (c). I.e. generating L candidate vectors- >L is more than or equal to 1 and less than or equal to L is selected from->Is a solution to the approximation of (a).
There remains a need to define and solve the power control problem by which candidate vectors are scaled to lie in a set of viable solutions. The definition of the above-mentioned problem is given by the following formula,
p m ≥0,1≤m≤M,t≥0,
wherein alpha is m 、β m,j Sum mu k,m Is defined asAnd->Again representing the scaling parameters of the mth precoding vector. Can prove that
In addition, in the case of the optical fiber,and->Is t and P max Are monotonically non-decreasing for a given weight eta m ,1≤m≤M。
In other words, and forSimilar bisection methods as described in the solution of (a) can also be used for +.>Is a solution to (a). That is, the bisection method is applied at t such that +.>For dichotomy, t l Again set to zero, t u Set to->Is the optimum value of (3). If a feasible solution of the first candidate vector is found +.>M is equal to or less than 1 and M is equal to or less than 1, and the M is scaled to be +.>A scaled set of precoding vectors among the L candidates that achieve the maximum-minimum communication SINR is selected as a column of the precoding matrix W. Representing that the predefined tolerance dichotomy is running. The overall computational complexity is again determined by the SDP problemAnd the computational complexity of the L-linear program dominates, for the question +.>The number of solutions of the SDP problem and the L linear programs is as large as the number of iterations of the dichotomy employed. In practice, this is not a big problem, as the aforementioned dichotomies typically require a rather small number of iterations to converge.
Wherein the vector isAnd->K is more than or equal to K and is defined as +.>Below. Application transform->Wherein X is m ≥0,rank(X m ) =1 and 1.ltoreq.m.ltoreq.M is +.>In the present description, the expression is given below
X m ≥0,rank(X m )=1,1≤m≤M,
Wherein matrix R 0 And R is k K is more than or equal to 1 and less than or equal to KThe following definitions. By eliminating the rank-1 constraint and due to the positive nature of the numerator and denominator in the SINR expression and objective function, the relaxation problem is a continuous concave/convex fractional programming problem. Thus, the Dinkelbach method can be used to transform it into a series of sub-problems and guarantee convergence to the global optimum of the original problem. By usingRepresenting the optimal solution of the nth sub-problem, i.e
Wherein the method comprises the steps ofIs an auxiliary variable. For a fixed zeta n Value, optimal matrix->SDP question obtained by solving by interior point methodThe problem is obtained. Similarly, given an optimal matrix +.>Is known, the auxiliary variable ζ n Can be directly determined by
That is, the just described alternating minimization procedure can be applied to solveSince rank-1 is restricted to the sub-problem->Is deleted, the optimal solution may relate to the matrix +.>Its rank is higher than 1, such as +.> Is the case in (a). Thus, resorting again to Gaussian randomization techniques to generate L candidate vectors +. >1.ltoreq.l.ltoreq.L is selected from>Is a solution to the approximation of (a). />
p m ≥0,1≤m≤M,t≥0
Wherein alpha is m 、β m,j Sum mu k,m Is defined asAnd->A scaling parameter representing the mth precoding vector. At->In the definition of +.>And->Is to be added to the fact that (1) is a new product. Thus, the Dinkelbach method can be used again for switching +.>The fractional part of (1) is defined as in the following series of sub-problems
Wherein the method comprises the steps ofIs the solution of the nth sub-problem, +.>Is an auxiliary variable. />An alternate minimization process may be applied to the solution of (a). Zeta was observed for fixation n The value, the problem that arises is a constraint with M non-negative variables and m+1 linear inequalities. Thus, it can be solved by the interior point method. Then, give +.>Optimum value of variable, auxiliary variableThe update is directly carried out as that,
given solutionThe first candidate vector is then scaled to +.>For all 1.ltoreq.m.ltoreq.M. The scaled set of precoding vectors that achieve the maximum radar output selects the L candidate SINRs as columns of the precoding matrix W.
E represents a predefined tolerance for dinkelbach-based method operation. The overall computational complexity is mainly due to the SDP problemThe calculation complexity of (a) is determined by (a) and (b) each iteration is respectively>And->
Example 2:
as shown in the figure, the present embodiment provides a dual-function radar communication method apparatus, which includes a signal transceiver module 401, a total power minimization construction module 402, a beam forming module 403, a pre-coding module 404, and a power control module 405, wherein:
A signal transceiver module 401, configured to introduce a receiving uniform linear antenna array, hereinafter referred to as ULA, and in the dual-function radar communication system, a base station at a transmitting end sends signals to a plurality of single-antenna users through ULA, and at the same time, a receiving end receives radar signals by using a special ULA;
a total power minimization construction module 402, configured to collect statistical knowledge of channel state information at the base station end, and construct a transmission total power minimization problem by satisfying service quality constraints of communication and radar parts, i.e.
s.t.ξ m (W)≥η m ,1≤m≤M,
γ(W,c)≥η,
Where W is a T×M complex linear precoding matrix, c is a linear R×1 receive beamforming vector,andare respectively connected withThreshold value related to signal and radar quality of service, +.>Representing a positive real number, T representing the number of elements transmitting ULA, R represents the number of elements that receive the ULA, M represents the total number of user terminals, I.I F Representing the Frobenius matrix norm, ζ m (W) represents the received signal-to-interference-and-noise ratio of the mth UT, expressed as +.>Wherein the signal-to-interference-plus-noise ratio is hereinafter referred to as SINR, (-) H Self-conjugate matrix representing vector/matrix, w m And w k Is the m-th column and the k-th column of the matrix W,>and->Respectively represent w m And w k Is a self-conjugate matrix of h m Represents the mth column of matrix H, +. >Represents h m Self-conjugate matrix of>Represents the noise variance of the vector z, z is an Mx1 additive Gaussian white noise vector, and γ (W, c) represents the output SINR of the radar beamforming, expressed as +.>Wherein->And->Representing the complex amplitudes of the target and the kth interferer, c H Is the self-conjugate matrix of vector c, W H Is the self-conjugate matrix of matrix W, +.>Represents the noise variance of the vector u, which represents the circularly symmetric complex Gaussian white noise vector, θ 0 And theta k Representing the angles of the target and the kth interference source in the azimuth, A (theta 0 ) And A (theta) k ) Positive definite matrix representing the azimuth angles of the target and the kth interference source respectively, A H (θ 0 ) And A H (θ k ) Respectively represent A (theta) 0 ) And A (theta) k ) Self-conjugate matrix of>a r (θ) is the R1 vector of propagation delays from the source at angle θ to the radar receiving element, (-) T Representing a transpose of the vector/matrix expressed asIs a t (θ), a t (θ) represents a T×1 emission steering vector expressed as +.>
a pre-coding module 404, configured to form an optimal radar beamforming matrix c * Substitution intoIn (1) rank one method is adopted>The reduction of the power minimization problem to the semi-definite programming SDP problem is as follows
X m ≥0,
Wherein X is m Rank 1, tr (·) represents the trace of the matrix,w j is the j-th column of the matrix W, +.>Is w j Self-conjugate matrix of>And is also provided with(c * ) H Is c * Self-conjugate matrix of>And->Represents the target and the kth modified optimal radar beamforming matrix, respectively,/for each radar beam>And->Are respectively->And->Solving the optimization problem by an interior point method, and if the rank one is not satisfied, finding the problem by Gaussian randomization>For each precoding vector w m L candidate vectors generated, i.e.>Wherein U is m And->Respectively a matrix consisting of eigenvectors and a diagonal matrix,>representing variance as unit matrix I T Complex gaussian matrix of (a), matrix U m Sum sigma m Calculating and decomposing the optimal matrix from the eigenvalues>I.e. < ->Generating candidate vectors such thatRepresenting a desired operator;
a power control module 405 for further modifying the optimal precoding matrix to meet the communication and radar sensing requirements by power control, the optimization problem being constructed as
p m ≥0,
Wherein,,is the square value of the European norm of the precoding matrix,>and->Respectively representing the mth precoding vector parameter corrected by the mth channel matrix and the jth precoding vector parameter corrected by the mth channel matrix,/ >And->Respectively w m And w j W is a self-conjugate matrix of m And w j Respectively denoted as mth candidate vector and jth candidate vector, gamma m,m And gamma k,m Representing the output SINR received at the mth UT interfered by the mth interferer and the output SINR received at the mth UT interfered by the kth interferer, respectively,>scaling parameters for the mth and jth precoding vectors, respectively,/for the mth and jth precoding vectors>Representing real numbers, problem->For linear programming with M non-negative variables and M+1 linear inequality constraints, solving the problem by the interior point method +.>
Specific implementation of each module in this embodiment may be referred to embodiment 1 above, and will not be described in detail herein; it should be noted that, the apparatus provided in this embodiment is only exemplified by the division of the above functional modules, and in practical application, the above functional allocation may be performed by different functional modules according to needs, that is, the internal structure is divided into different functional modules, so as to perform all or part of the functions described above.
Example 3:
the present embodiment provides a computer device, which may be a computer, as shown in fig. 5, and is connected through a system bus 501, where the processor is configured to provide computing and control capabilities, the memory includes a nonvolatile storage medium 506 and an internal memory 507, where the nonvolatile storage medium 506 stores an operating system, a computer program, and a database, and the internal memory 507 provides an environment for the operating system and the computer program in the nonvolatile storage medium, and when the processor 502 executes the computer program stored in the memory, the processor 502 implements a dual-function radar communication method provided in the foregoing embodiment 1, where the implementation steps of the dual-function radar communication method are as follows:
A multi-antenna base station adopts a uniform linear antenna array (ULA) to transmit signals to a plurality of single-antenna users on a downlink, and simultaneously adopts a special ULA to receive radar signals at a receiving end; the base station side collects the statistical knowledge of the channel state information and constructs the problem of minimum transmission total power by meeting the service quality constraint of the communication and radar parts; giving a precoding matrix standard orthogonalization constraint to maximize radar output signal-to-noise ratio to obtain an optimal radar receiving beamforming matrix; giving a receiving beam forming matrix, simplifying a power minimization problem into a semi-definite programming problem by using a rank-one method, and solving an optimal precoding matrix by using an interior point method; and finally, further correcting the optimal precoding matrix through power control to meet the communication and radar sensing requirements.
Example 4:
the present embodiment provides a storage medium, which is a computer readable storage medium storing a computer program, where the computer program is executed by a processor to implement a dual-function radar communication method according to the foregoing embodiment 1, and the implementation steps of the dual-function radar communication method are as follows: a multi-antenna base station adopts a uniform linear antenna array (ULA) to transmit signals to a plurality of single-antenna users on a downlink, and simultaneously adopts a special ULA to receive radar signals at a receiving end; the base station side collects the statistical knowledge of the channel state information and constructs the problem of minimum transmission total power by meeting the service quality constraint of the communication and radar parts; giving a precoding matrix standard orthogonalization constraint to maximize radar output signal-to-noise ratio to obtain an optimal radar receiving beamforming matrix; giving a receiving beam forming matrix, simplifying a power minimization problem into a semi-definite programming problem by using a rank-one method, and solving an optimal precoding matrix by using an interior point method; the optimal precoding matrix is further modified by power control to meet communication and radar sensing requirements.
The storage medium described in the present embodiment may be a magnetic disk, an optical disk, a computer memory, a random access memory (RAM, random Access Memory), a U-disk, a removable hard disk, or the like.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.
Claims (6)
1. The method for the communication of the double-function radar is characterized by comprising the following implementation steps:
s1, in a dual-function radar communication system, a multi-antenna base station adopts a uniform linear antenna array on a downlink to send signals to a plurality of single-antenna user terminals, and meanwhile, a receiving end adopts a uniform linear antenna array to receive and transmit radar detection waveforms and detect point targets at the same time, wherein the dual-function radar communication is hereinafter referred to as DFRC, the uniform linear antenna array is hereinafter referred to as ULA, the base station is hereinafter referred to as BS, and the user terminals are hereinafter referred to as UT;
s2, the base station collects the statistical knowledge of the channel state information, and constructs the problem of total transmission power minimization by meeting the service quality constraint of the communication and radar parts, namely
s.t.ξ m (W)≥η m ,1≤m≤M,
γ(W,c)≥η,
Where W is a T×M complex linear precoding matrix, c is a linear R×1 receive beamforming vector,andthreshold values related to communication and radar quality of service, respectively,/->Representing a positive real number, T representing the number of elements transmitting ULA, R represents the number of elements that receive the ULA, M represents the total number of user terminals, I.I F Representing the Frobenius matrix norm, ζ m (W) represents the received signal-to-interference-and-noise ratio of the mth UT, expressed as
Wherein the signal-to-interference-plus-noise ratio is hereinafter referred to as SINR, (-) H Self-conjugate matrix representing vector/matrix, w m And w k Is the m-th and k-th columns of the matrix W,and->Respectively represent w m And w k Is a self-conjugate matrix of h m Represents the mth column of matrix H, +.>Represents h m Self-conjugate matrix of>Represents the noise variance of the vector z, z is an Mx1 additive Gaussian white noise vector, and γ (W, c) represents the output SINR of the radar beamforming, expressed as
Wherein the method comprises the steps ofAnd->Representing the complex amplitudes of the target and the kth interferer, c H Is the self-conjugate matrix of vector c, W H Is the self-conjugate matrix of matrix W, +.>Representing the noise variance of the vector u, u representingCircularly symmetric complex Gaussian white noise vector, θ 0 And theta k Representing the angles of the target and the kth interference source in the azimuth, A (theta 0 ) And A (theta) k ) Positive definite matrix representing the azimuth angles of the target and the kth interference source respectively, A H (θ 0 ) And A H (θ k ) Respectively represent A (theta) 0 ) And A (theta) k ) And (2) self-conjugate matrix ofa r (θ) is the R1 vector of propagation delays from the source at angle θ to the radar receiving element, (-) T Representing the transpose of the vector/matrix with the expression +.> Is a t Transpose of (θ), a t (θ) represents a T×1 emission steering vector expressed as +.>
S3, giving an optimal value W of the precoding matrix * Optimizing radar receive beamforming matrix c by maximizing radar output SINR * The optimization problem is as follows:
s4, the optimal radar beam forming matrix c * Substitution intoIn (1) rank one method is adopted>Minimizing power problemsThe SDP problem reduced to semi-definite programming is as follows
X m ≥0,
Wherein X is m Rank 1, tr (·) represents the trace of the matrix,w j is the j-th column of the matrix W,is w j Self-conjugate matrix of>And is also provided with(c * ) H Is c * Self-conjugate matrix of>And->Represents the target and the kth modified optimal radar beamforming matrix, respectively,/for each radar beam>And->Are respectively->And->Solving the optimization problem by an interior point method, and if the rank one is not satisfied, finding the problem by Gaussian randomization>For each precoding vector w m L candidate vectors generated, i.e.>Wherein U is m And->Respectively a matrix consisting of eigenvectors and a diagonal matrix, >Representing variance as unit matrix I T Complex gaussian matrix of (a), matrix U m Sum sigma m Calculating and decomposing the optimal matrix from the eigenvalues>I.e. < ->Generating candidate vectors such that-> Representing a desired operator;
s5, further correcting the optimal precoding matrix through power control to meet communication and radar sensing requirements, and constructing an optimization problem
p m ≥0,
Wherein,,is the square value of the European norm of the precoding matrix,>and->Respectively representing the mth precoding vector parameter corrected by the mth channel matrix and the jth precoding vector parameter corrected by the mth channel matrix,/>And->Respectively w m And w j W is a self-conjugate matrix of m And w j Respectively denoted as mth candidate vector and jth candidate vectorAmount of gamma m,m And gamma k,m Representing the output SINR received at the mth UT interfered by the mth interferer and the output SINR received at the mth UT interfered by the kth interferer, respectively,>scaling parameters for the mth and jth precoding vectors, respectively,/for the mth and jth precoding vectors>Representing real numbers, problem->For linear programming with M non-negative variables and M+1 linear inequality constraints, solving the problem by the interior point method +.>
2. The method according to claim 1, wherein the construction of two other optimization problems by the control variable method in the step S2 is as follows:
If the signal-to-interference-and-noise ratio is designed in a robust way under the constraint of the total transmitting power, the service quality of the radar is ensured, and the optimization problem is constructed as follows:
s.t.γ(W,c)≥η,
wherein P is max Is the maximum transmitting power supported by the DFRC system, and the constant weight is 1/eta m Illustrating different service levels between UTs;
if the signal-to-interference-and-noise ratio performance of the radar is maximized, the total transmitting power is limited and the communication service quality is guaranteed, and the optimization problem is constructed as follows:
3. the method according to claim 1, wherein in the step S3, when the radar receiving beamforming matrix is optimized, in order to obtain the analysis result of the optimal radar receiving beamforming matrix, assume W * (W * ) H =I T Further converting the optimization problem into
The optimal radar receiving beam forming matrix corresponding to the optimization problem is as follows
4. A dual function radar communication device according to the dual function radar communication method of any one of claims 1 to 3, characterized in that the dual function radar communication device comprises:
the signal receiving and transmitting module is used for introducing a receiving uniform linear antenna array, namely receiving the uniform linear antenna array is called ULA (ultra low power) for short, a base station at a transmitting end in the dual-function radar communication system transmits signals to a plurality of single-antenna users through the ULA, and meanwhile, a receiving end receives radar signals by adopting a special ULA;
A total power minimization construction module, which is used for the base station to collect the statistical knowledge of the channel state information, and constructs the problem of total power minimization of transmission by meeting the service quality constraint of the communication and radar part,
i.e. s.t. ζ m (W)≥η m ,1≤m≤M,
γ(W,c)≥η,
Where W is a T×M complex linear precoding matrix, c is a linear R×1 receive beamforming vector,andthreshold values related to communication and radar quality of service, respectively,/->Representing a positive real number, T representing the number of elements transmitting ULA, R represents the number of elements that receive the ULA, M represents the total number of user terminals, I.I F Representing the Frobenius matrix norm, ζ m (W) represents the received signal-to-interference-and-noise ratio of the mth UT, expressed as
Wherein the signal-to-interference-plus-noise ratio is hereinafter referred to as SINR, (-) H Self-conjugate matrix representing vector/matrix, w m And w k Is the m-th and k-th columns of the matrix W,and->Respectively are provided withRepresents w m And w k Is a self-conjugate matrix of h m Represents the mth column of matrix H, +.>Represents h m Self-conjugate matrix of>Represents the noise variance of the vector z, z is an Mx1 additive Gaussian white noise vector, and γ (W, c) represents the output SINR of the radar beamforming, expressed as
Wherein the method comprises the steps ofAnd->Representing the complex amplitudes of the target and the kth interferer, c H Is the self-conjugate matrix of vector c, W H Is the self-conjugate matrix of matrix W, +.>Represents the noise variance of the vector u, which represents the circularly symmetric complex Gaussian white noise vector, θ 0 And theta k Representing the angles of the target and the kth interference source in the azimuth, A (theta 0 ) And A (theta) k ) Positive definite matrix representing the azimuth angles of the target and the kth interference source respectively, A H (θ 0 ) And A H (θ k ) Respectively represent A (theta) 0 ) And A (theta) k ) And (2) self-conjugate matrix ofa r (θ) is the Rx1 vector of propagation delay from the source at angle θ to the radar receiving elementAmount (·) T Representing the transpose of the vector/matrix with the expression +.> Is a t Transpose of (θ), a t (θ) represents a T×1 emission steering vector expressed as +.>
A beam forming module for giving the optimal value W of the precoding matrix * Optimizing radar receive beamforming matrix c by maximizing radar output SINR * The optimization problem is as follows:
a pre-coding module for forming the optimal radar beam forming matrix c * Substitution intoIn (1) rank one method is adopted>The reduction of the power minimization problem to the semi-definite programming SDP problem is as follows
X m ≥0,
Wherein X is m Rank 1, tr (·) represents the trace of the matrix,w j is the j-th column of the matrix W,is w j Self-conjugate matrix of>And is also provided with(c * ) H Is c * Self-conjugate matrix of>And->Represents the target and the kth modified optimal radar beamforming matrix, respectively,/for each radar beam >And->Are respectively->And->Solving the optimization problem by an interior point method, and if the rank one is not trueFind problem by gaussian randomization +.>For each precoding vector w m L candidate vectors generated, i.e.>Wherein U is m And->Respectively a matrix consisting of eigenvectors and a diagonal matrix,>representing variance as unit matrix I T Complex gaussian matrix of (a), matrix U m Sum sigma m Calculating and decomposing the optimal matrix from the eigenvalues>I.e. < ->Generating candidate vectors such that Representing a desired operator;
the power control module is used for further correcting the optimal precoding matrix through power control to meet communication and radar sensing requirements, and the optimization problem is constructed
p m ≥0,
Wherein,,is the square value of the European norm of the precoding matrix,>and->Respectively representing the mth precoding vector parameter corrected by the mth channel matrix and the jth precoding vector parameter corrected by the mth channel matrix,/>And->Respectively w m And w j W is a self-conjugate matrix of m And w j Respectively denoted as mth candidate vector and jth candidate vector, gamma m,m And gamma k,m Representing the output SINR received at the mth UT interfered by the mth interferer and the output SINR received at the mth UT interfered by the kth interferer, respectively, >Scaling parameters for the mth and jth precoding vectors, respectively,/for the mth and jth precoding vectors>Representation ofReal number, problem->For linear programming with M non-negative variables and M+1 linear inequality constraints, solving the problem by the interior point method +.>
5. A computer device comprising a processor and a memory for storing a program executable by the processor, wherein the processor, when executing the program stored in the memory, implements the method of bi-functional radar communication of any of claims 1-3.
6. A storage medium storing a program, wherein the program, when executed by a processor, implements the method of dual function radar communication of any one of claims 1-3.
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