Spatial multiplexing time slot allocation method and system based on underwater acoustic channel conflict matrix

Abstract

The invention discloses a spatial multiplexing time slot allocation method and system based on an underwater acoustic channel conflict matrix, and the method comprises the steps: firstly calculating a link signal receiving success probability in an underwater acoustic network according to an underwater acoustic transmission link model; secondly, generating a channel conflict matrix according to the underwater network topology information and the link signal receiving success probability; then, constructing a time slot allocation matrix for marking the time slot occupation condition of the nodes, and constructing a multi-objective optimization function for time slot allocation from the aspects of time slot conflict condition, time slot occupancy and allocation uniformity; and finally, according to the underwater acoustic channel conflict matrix and the time slot allocation matrix, searching an optimal solution of time slot allocation through global search. According to the method, distribution of underwater channel resources is comprehensively considered from three aspects of time slot conflict, time slot utilization rate and time slot distribution uniformity, an effective fitness evaluation mechanism is established, the channel resources can be fully utilized, and the underwater acoustic communication performance is improved.

Description

Technical Field

[0001] The invention relates to a method and system for allocating time slots for spatial multiplexing based on an underwater acoustic channel conflict matrix, and is particularly suitable for a time slot allocation scheme for underwater network time division multiple access, belonging to the field of communication technology. Background Art

[0002] In marine research, establishing a highly reliable underwater acoustic communication network is the most important means of obtaining underwater information. However, the particularity of the underwater acoustic channel, such as high latency and narrow bandwidth, brings many difficulties to the design of the MAC protocol of the underwater acoustic communication network. If these problems cannot be properly handled, it will be impossible to build an excellent underwater acoustic communication network and make full use of limited channel resources. Therefore, the research on efficient MAC protocols for underwater acoustic communication networks is a key direction in marine technology. Most of the MAC protocols for underwater acoustic communication networks improved based on TDMA have low adaptability. When faced with complex combinatorial optimization problems such as underwater channel resource allocation, they cannot consider time slot allocation schemes from multiple angles, and can only give local optimal solutions. Secondly, the optimal time slot allocation scheme that fully utilizes channel resources cannot be found in a short time.

[0003] Therefore, the main research topic of the present invention is to construct an underwater time slot allocation scheme evaluation model, abstract the underwater time slot allocation scheme into the search sample space, use global search to find the optimal solution, realize space multiplexing on the basis of time division multiplexing, and make full use of channel resources. Summary of the invention

[0004] Purpose of the invention: In order to solve the problems existing in the prior art, the present invention proposes a spatial multiplexing time slot allocation method and system based on the underwater acoustic channel conflict matrix, models the underwater time slot allocation, constructs a multi-factor evaluation system, evaluates the advantages and disadvantages of the time slot allocation scheme, and generates the globally optimal time slot allocation result through global search, so as to make full use of channel resources and improve the underwater acoustic communication performance.

[0005] Technical solution: To achieve the above purpose, the present invention provides a method for allocating time slots for spatial multiplexing based on an underwater acoustic channel conflict matrix, comprising the following steps:

[0006] Step 1: Calculate the probability of successful link signal reception in the underwater acoustic network according to the underwater acoustic transmission link model;

[0007] Step 2: Generate a channel conflict matrix based on the underwater network topology information and the probability of successful link signal reception;

[0008] Step 3: Construct a time slot allocation matrix to mark the time slots occupied by nodes. From the perspectives of time slot conflicts, time slot occupancy rate and allocation uniformity, construct a multi-objective optimization function for time slot allocation. The time slot conflicts are measured by summing up the number of conflicts among nodes in each time slot. The time slot occupancy rate is measured by the inverse of the average number of time slots occupied by each node. The time slot allocation uniformity is measured by the variance of the number of time slots allocated to each node.

[0009] Step 4: Based on the underwater acoustic channel conflict matrix and the time slot allocation matrix, find the optimal solution for time slot allocation through global search.

[0010] Preferably, in the first step, according to the underwater acoustic transmission link model, the probability of successful reception of the link signal in the underwater acoustic network is calculated, including: according to the bit error rate P of the actual underwater acoustic channel transmission model e , the probability of successful signal reception is calculated as P s =1-P e According to the underwater acoustic network topology, based on the location information of the node pair and the underwater acoustic channel model, the signal reception probability of the node pair link is calculated, and the underwater acoustic network reception probability matrix P is constructed. Its size is N*N, where N is the number of nodes, and the matrix element value is the signal reception success probability P of each pair of node links. s .

[0011] Preferably, in the second step, a channel conflict matrix is ​​generated according to the location information of the underwater network topology nodes and the probability of successful link signal reception, including:

[0012] When the topology and actual link quality are known, nodes with non-overlapping communication ranges are allowed to share a time slot based on the node location information. First, a preliminary channel conflict matrix is ​​generated based on the network topology and node information. The judgment conditions are:

[0013] Condition 1: When a pair of nodes have a mutual signal conflict, they cannot reuse the same time slot;

[0014] Condition 2: When a pair of nodes sends a signal that will cause a conflict with a third-party node, they cannot reuse the same time slot.

[0015] According to the above two conditions, the actual position information and the underwater acoustic link are mapped into a preliminary channel conflict matrix based on the maximum transmission range; when there are N nodes in the network, an N*N preliminary channel conflict matrix A is constructed to represent it; among them, the element A ij A takes 0 or 1, indicating whether nodes i and j conflict with each other in sending messages. If nodes i and j conflict with each other in sending messages, then A ij =1;

[0016] Secondly, according to the underwater acoustic network receiving probability matrix P and the preliminary channel conflict matrix A, a two-dimensional N*N actual channel conflict matrix C is constructed; when there is a mutual conflict between node pairs, it means that there is a channel conflict, then C ij =1; when there is a third-party conflict between the node pairs, it means that there is a probabilistic channel conflict, and its probability is the sum of all potential conflict probabilities;

[0017]

[0018] Where P ik , P jk are the success probability of receiving link signals between node i and node k, and between node j and node k, respectively, ik , A jk They respectively indicate whether there is a conflict between the corresponding nodes in sending signals.

[0019] Preferably, the objective function f1 for optimizing time slot conflicts is expressed as:

[0020]

[0021] in, Indicates whether node i occupies the jth time slot and whether it conflicts. ij and T ik is the occupancy of time slots j and k by node i in the time slot allocation matrix. The value 1 indicates occupancy and 0 indicates unoccupancy. ik is the conflict situation between the i-th node and the k-th node in the channel conflict matrix.

[0022] As a preferred embodiment, the objective function f2 for improving time slot utilization is expressed as:

[0023]

[0024] in, Represents the average number of time slots occupied by each node.

[0025] As a preference, the objective function f3 for improving the uniformity of time slot allocation is expressed as:

[0026]

[0027] Preferably, a linear normalization method is used to de-dimensionalize the multi-objective function, and a linear weighting method is used to achieve multi-objective optimization. The constraint condition of the multi-objective optimization is to ensure that each time slot is allocated and each node is allocated at least one time slot.

[0028] Preferably, in the fourth step, the coding mapping method of searching the sample space is as follows: the allocation result of the time slot is represented by the time slot allocation matrix T, and it is mapped to the sample vector in the form of binary coding: assuming that there are M time slots allocated to N nodes, then create an N*M matrix, the elements in the matrix are composed of 0 or 1, and the matrix is ​​mapped to the sample vector column by column.

[0029] A computer system comprises a memory, a processor and a computer program / instruction stored in the memory and executable on the processor, wherein when the computer program / instruction is executed by the processor, the steps of a spatial multiplexing time slot allocation method based on an underwater acoustic channel conflict matrix are implemented.

[0030] A computer program product comprises a computer program / instruction, wherein when the computer program / instruction is executed by a processor, the steps of the spatial multiplexing time slot allocation method based on the underwater acoustic channel conflict matrix are implemented.

[0031] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0032] The spatial multiplexing time slot allocation method based on the underwater acoustic channel conflict matrix provided by the present invention realizes spatial multiplexing on the basis of time division multiplexing according to the underwater acoustic channel conflict matrix and the time slot allocation matrix, and makes full use of channel resources; the time slot allocation scheme generated by evaluating the fitness function is comprehensively considered from three aspects: time slot conflict, time slot utilization and time slot allocation uniformity; an underwater time slot allocation search sample space is constructed, and a globally optimal time slot allocation result is generated through a global search, thereby improving network throughput, reducing end-to-end delay, reducing packet loss rate, and improving network stability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flowchart of the present invention. DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0035] like Figure 1 As shown, the embodiment of the present invention discloses a method for allocating time slots for spatial multiplexing based on an underwater acoustic channel conflict matrix, and the main steps are as follows:

[0036] Step 1: According to the underwater acoustic transmission link model, calculate the probability of successful link signal reception in the underwater acoustic network.

[0037] The channel attenuation of an underwater acoustic signal with a modulation frequency of f and a straight line transmission distance d is expressed as:

[0038] A(d,f)=A0d ka(f) d #(1)

[0039] Among them, A0 is the normalization factor, k represents the geometric figure of propagation, k = 1 represents cylindrical propagation, k = 2 represents spherical propagation; a(f) represents the absorption index of water sound in the ocean. The attenuation can be expressed in dB form as:

[0040]

[0041] In the above expression, the signal attenuation can be divided into two parts. The first term, in which only the distance d acts as a variable, can be called diffusion loss, while the second term involving the frequency f is called absorption loss.

[0042] Ocean noise is divided into: ocean current noise N i (f) Ship noise N s (f), wave noise N w (f) and thermal noise N th (f). The main influencing frequency band of ocean current noise is within the lower frequency of 10Hz; between 10 and 100Hz, the noise generated by ship activities is the main noise; in the frequency band of 100 to 100kHz, waves are the main influencing factor of environmental noise, and its modeling object involves not only frequency but also wind speed w; in the frequency band above 100kHz, thermal noise dominates. The total environmental noise of the entire network is expressed as:

[0043] N(f)=N i (f)+N s (f)+N w (f)+N th (f)#(3)

[0044] Based on the attenuation model of the underwater acoustic channel and the environmental noise model of the ocean, the narrowband underwater acoustic signal receiving signal-to-noise ratio (SNR) is expressed as:

[0045]

[0046] Among them, P tx represents the transmission power, and Δf represents the frequency bandwidth.

[0047] According to the Rayleigh channel model, the receiving bit error rate of the system is:

[0048]

[0049] Therefore, the probability of successful signal reception is

[0050] P s =1-P e (d,f)#(6)

[0051] According to the underwater acoustic network topology, based on the location information of the node pair and the underwater acoustic channel model, the signal reception probability of the node pair link is calculated, and the underwater acoustic network reception probability matrix P is constructed. The matrix element value is the signal reception success probability P of each pair of node links. s .

[0052] Step 2: Generate the channel conflict matrix C based on the location information of the underwater network topology nodes and the probability of successful link signal reception. When the topology structure and actual link quality are known, nodes with non-overlapping communication ranges are allowed to share a time slot based on the node location information. First, a preliminary channel conflict matrix is ​​generated based on the network topology and node information, and its judgment conditions are:

[0053] Condition 1: When a pair of nodes have a mutual signal conflict, they cannot reuse the same time slot;

[0054] Condition 2: When a pair of nodes sends a signal that will cause a conflict with a third-party node, they cannot reuse the same time slot.

[0055] According to the above two conditions, the actual location information and the underwater acoustic link are mapped into a preliminary channel conflict matrix based on the maximum transmission range. When there are N nodes in the network, an N*N preliminary channel conflict matrix A is constructed to represent it. Among them, in the preliminary channel conflict matrix, the element A ij It can only take 0 or 1, indicating whether node i and node j conflict with each other in sending messages. When node i and node j conflict with each other in sending messages, then A ij =1.

[0056] Secondly, according to the underwater acoustic network receiving probability matrix P and the preliminary channel conflict matrix A, a two-dimensional N*N actual channel conflict matrix C is constructed. Among them, when there is a conflict between node pairs, it means that there is a channel conflict, then C ij = 1. When there is a third-party conflict between node pairs, it means that there is a probabilistic channel conflict, and its probability is the sum of all potential conflict probabilities.

[0057]

[0058] Step 3: In the third step, the time slot allocation is modeled from the perspectives of time slot conflict, time slot occupancy and allocation uniformity, and a multi-factor evaluation system is constructed through multi-objective optimization to evaluate the pros and cons of the time slot allocation scheme. In this embodiment, a time slot allocation matrix is ​​constructed to mark the time slot occupation of nodes, and a multi-objective optimization function is constructed for time slot allocation from the perspectives of time slot conflict, time slot occupancy and allocation uniformity; the time slot conflict is measured by counting the sum of whether each node occupies each time slot, the time slot occupancy is measured by the inverse of the average number of time slots occupied by each node, and the time slot allocation uniformity is measured by the variance of the number of time slots allocated to each node.

[0059] First, the time slot allocation scheme is modeled. According to the time slots occupied by nodes, a two-dimensional N*M time slot allocation matrix T is constructed. Among them, N is the number of nodes to be allocated, M is the number of allocable time slots, and its t ij The value is 1 or 0, T ij =1 indicates that node i occupies time slot j to send a signal, t ij = 0 means that node i does not occupy time slot j to send a signal. Secondly, for the time slot conflict, time slot utilization and allocation uniformity faced by the time slot allocation problem, multi-objective optimization is adopted to comprehensively consider the relationship between the three to optimize the time slot allocation result.

[0060] Time slot conflict: Based on the channel conflict matrix and the time slot allocation matrix, it can be determined whether there is a conflict in the time slot allocation matrix T, and the probability of reception conflict is calculated based on the reception probability matrix. Construct an objective function to optimize time slot conflicts, and calculate the reception conflict in the time slot under the time slot allocation scheme based on the node reception probability matrix, and then optimize the time slot conflict under the time slot allocation scheme. It optimizes the objective function to reflect the time slot conflict situation, and calculates the time slot occupancy of the population individuals and the reception conflict of the network topology. Assuming that there are M time slots and N nodes in the network, define R ij Indicates whether the i-th node occupies the j-th time slot, as shown in Formula 8, where T ik represents the occupation of the kth time slot by the i-th node in the time slot allocation matrix, C ik Represents the conflict situation between the i-th node and the k-th node in the channel conflict matrix.

[0061]

[0062] In time slot allocation, the objective function f1 to reduce the probability of time slot conflict and optimize time slot conflict is as follows:

[0063]

[0064] Among them, T ij and T ikis the occupancy of time slots j and k by node i in the time slot allocation matrix, C ik is the conflict situation between the i-th node and the k-th node in the channel conflict matrix, M is the number of time slots, and N is the number of nodes.

[0065] Slot occupancy rate: Define X as the uniformity of slot allocation in the whole network to evaluate the slot occupancy rate of the slot allocation scheme. The objective function for optimizing slot utilization reflects the average number of slots occupied by each node. The optimization objective function reflects the slot utilization rate of the allocation scheme, which is calculated based on the slot allocation matrix. The number of slots occupied by each node is X i The average number of time slots occupied by each node is for:

[0066]

[0067] Among them, T ij Indicates the occupancy of the j-th time slot by the i-th node. The bigger the better, where X i >1, that is, each point will be assigned at least one time slot. Therefore, the objective function f2 for improving time slot utilization is:

[0068]

[0069] Distribution uniformity: Defining S 2 The variance of the uniformity of the time slot allocation of the whole network is used to measure the uniformity of the time slot allocation of the whole network. In order to make the number of time slots occupied by the nodes of the time slot allocation scheme uniform, the establishment of its optimization objective function should be calculated based on the variance of the number of time slot allocations. The calculation formula is as follows:

[0070]

[0071] S 2 The smaller the variance of time slot allocation uniformity, the better, indicating that the time slot allocation is more uniform. The objective function f3 for improving the time slot allocation uniformity is:

[0072]

[0073] In summary, optimization functions are established for different objectives of underwater time slot allocation, and are calculated through the time slot allocation matrix T and the channel conflict matrix C. Its time slot allocation scheme should constrain the allocation of time slots and nodes, and should ensure that each time slot is allocated and each node is allocated at least one time slot. Therefore, the underwater time slot allocation function model is as follows:

[0074]

[0075] The constraints are:

[0076]

[0077] By using the linear normalization method to de-dimensionalize the objective function, its value is distributed in [0, 1], and the original objective function will not change its value range due to linear transformation.

[0078] First, define the maximum values ​​of each objective function in the H time slot allocation schemes, respectively: i,max and f i,min Then use f i,max and f i,min , the 3*H objective functions are dedimensionalized, and the processed objective functions are as follows:

[0079]

[0080] The value of the normalized objective function is distributed in [0, 1], and the original objective function will not change its value range due to linear transformation. The weighted objective function for underwater time slot allocation is expressed as:

[0081]

[0082] Among them, L is the number of objective functions, W i is the objective function f i ′ weighting coefficient, and W i Greater than or equal to 0, T1, T2, ..., T H In order to find the range where the target F minimum value is located, the restriction condition of the weighting coefficient is:

[0083]

[0084] Since the optimization direction is positive, the inverse of F is defined as the fitness function, and G>0, as shown below:

[0085]

[0086] Among them, f1′ is the objective function of time slot conflict after quantization, f2′ is the objective function of time slot utilization, f3′ is the objective function of time slot allocation uniformity, and W1, W2 and W3 are the weight ratios of these three objective functions.

[0087] Step 4: Based on the underwater acoustic channel conflict matrix and the time slot allocation scheme evaluation model, the coding mapping constructs the underwater time slot allocation search sample space, and through global search, finds the optimal solution for time slot allocation;

[0088] The following is further described with reference to an exemplary embodiment of the present invention:

[0089] (1) Configure and initialize the underwater acoustic network.

[0090] (2) According to the underwater acoustic transmission link model, the probability of successful link signal reception in the underwater acoustic network is calculated. Then, according to the underwater network topology information and the probability of successful link signal reception, the channel conflict matrix is ​​generated.

[0091] (3) The time slot allocation is modeled from the perspectives of time slot conflict, time slot occupancy, and allocation uniformity. Through multi-objective optimization, a multi-factor evaluation system is constructed to evaluate the advantages and disadvantages of the time slot allocation scheme. For the time slot conflict, time slot utilization, and allocation uniformity faced by the time slot allocation problem, multi-objective optimization is adopted to comprehensively consider the relationship between the three to optimize the time slot allocation result.

[0092] Assume that there are H time slot allocation matrices, denoted as {T1,T2,...,T H}, according to the above formula, the value of the optimized time slot conflict objective function f1 of each time slot allocation matrix is ​​{f 11 ,f 12 ,...,f 1H}, then select the maximum and minimum values ​​among these values, and use f 1,max and f 1,min The function f1 is de-dimensionalized. Similarly, the objective function f2 of time slot utilization and the objective function f3 of time slot allocation uniformity are de-dimensionalized.

[0093] (4) According to the underwater time slot allocation scheme, it is abstracted into the sample vector, coded and mapped, and the search sample space is generated under the constraint condition; the time slot allocation result is represented by the time slot allocation matrix T, which is mapped into the sample vector in the form of binary coding. Assuming that there are M time slots allocated to N nodes, an N*M matrix is ​​created, and the elements in the matrix are composed of 0 or 1. The matrix is ​​mapped into the sample vector column by column, from the 1st column, the 2nd column, ..., the Mth column.

[0094] According to the underwater acoustic channel conflict matrix and the time slot allocation scheme evaluation model, the optimal solution for time slot allocation is found through global search. The global search algorithm can adopt simulated annealing algorithm, particle swarm algorithm and genetic algorithm.

[0095] A computer system disclosed in an embodiment of the present invention includes a memory, a processor, and a computer program / instruction stored in the memory and executable on the processor. When the computer program / instruction is executed by the processor, the steps of the spatial multiplexing time slot allocation method based on the underwater acoustic channel conflict matrix are implemented.

[0096] A computer program product disclosed in an embodiment of the present invention includes a computer program / instruction, and when the computer program / instruction is executed by a processor, the steps of the spatial multiplexing time slot allocation method based on the underwater acoustic channel conflict matrix are implemented.

[0097] The embodiments of the present invention are described in detail above. Specific examples are used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A spatial multiplexing time slot allocation method based on an underwater acoustic channel conflict matrix, characterized in that: The following steps are involved: Step 1: Calculate the probability of successful link signal reception in the underwater acoustic network according to the underwater acoustic transmission link model; Step 2: Generate a channel conflict matrix based on the underwater network topology information and the probability of successful link signal reception; Step 3: Construct a time slot allocation matrix to mark the time slots occupied by nodes, and construct a multi-objective optimization function for time slot allocation from the perspectives of time slot conflicts, time slot occupancy rate, and allocation uniformity; The time slot conflict is measured by counting the sum of whether each node occupies each time slot. The time slot occupancy rate is measured by the inverse of the average number of time slots occupied by each node. The time slot allocation uniformity is measured by the variance of the number of time slots allocated to each node. Step 4: Based on the underwater acoustic channel conflict matrix and the time slot allocation matrix, find the optimal solution for time slot allocation through global search.

2. The method for allocating time slots for spatial multiplexing based on the underwater acoustic channel conflict matrix according to claim 1, characterized in that: In the first step, according to the underwater acoustic transmission link model, the probability of successful reception of the link signal in the underwater acoustic network is calculated, including: according to the bit error rate P of the actual underwater acoustic channel transmission model e , the probability of successful signal reception is calculated as P s =1-P e According to the underwater acoustic network topology, based on the location information of the node pair and the underwater acoustic channel model, the signal reception probability of the node pair link is calculated, and the underwater acoustic network reception probability matrix P is constructed. Its size is N*N, where N is the number of nodes, and the matrix element value is the signal reception success probability P of each pair of node links. s .

3. The method for allocating time slots for spatial multiplexing based on an underwater acoustic channel conflict matrix according to claim 1, characterized in that: In the second step, according to the location information of the underwater network topology nodes and the probability of successful link signal reception, a channel conflict matrix is ​​generated, including: When the topology and actual link quality are known, nodes with non-overlapping communication ranges are allowed to share a time slot based on the node location information. First, a preliminary channel conflict matrix is ​​generated based on the network topology and node information. The judgment conditions are: Condition 1: When a pair of nodes have a mutual signal conflict, they cannot reuse the same time slot; Condition 2: When a pair of nodes sends a signal that will cause a conflict with a third-party node, they cannot reuse the same time slot. According to the above two conditions, the actual position information and the underwater acoustic link are mapped into a preliminary channel conflict matrix based on the maximum transmission range; when there are N nodes in the network, an N*N preliminary channel conflict matrix A is constructed to represent it; among them, the element A ij It takes 0 or 1, indicating whether node i and node j conflict with each other in sending messages. If node i and node j conflict with each other in sending messages, then A ij =1; Secondly, according to the underwater acoustic network receiving probability matrix P and the preliminary channel conflict matrix A, a two-dimensional N*N actual channel conflict matrix C is constructed; when there is a mutual conflict between node pairs, it means that there is a channel conflict, then C ij =1; when there is a third-party conflict between the node pairs, it means that there is a probabilistic channel conflict, and its probability is the sum of all potential conflict probabilities; Where P ik , P jk are the success probability of receiving link signals between node i and node k, and between node j and node k, respectively, ik , A jk They respectively indicate whether there is a conflict between the corresponding nodes in sending signals.

4. The method for allocating time slots for spatial multiplexing based on an underwater acoustic channel conflict matrix according to claim 1, characterized in that: The objective function f1 for optimizing time slot conflicts is expressed as: in, Indicates whether node i occupies the jth time slot and whether it conflicts. ij and T ik is the occupancy of time slots j and k by node i in the time slot allocation matrix. The value 1 indicates occupancy and 0 indicates unoccupancy. ik is the conflict situation between the i-th node and the k-th node in the channel conflict matrix, M is the number of time slots, and N is the number of nodes.

5. The method for allocating time slots for spatial multiplexing based on an underwater acoustic channel conflict matrix according to claim 1 is characterized in that: The objective function f2 to improve time slot utilization is expressed as: in, represents the average number of time slots occupied by each node, T ij Indicates the occupancy of the jth time slot by the i-th node, with a value of 1 for occupied and 0 for unoccupied. M is the number of time slots and N is the number of nodes.

6. The method for allocating time slots for spatial multiplexing based on underwater acoustic channel conflict matrix according to claim 1, characterized in that: The objective function f3 for improving the uniformity of time slot allocation is expressed as: Among them, T ij Indicates the occupancy of the jth time slot by the i-th node. The value 1 indicates occupation and 0 indicates unoccupancy. M is the number of time slots and N is the number of nodes.

7. The method for allocating time slots for spatial multiplexing based on an underwater acoustic channel conflict matrix according to claim 1, characterized in that: The linear normalization method is used to de-dimensionalize the multi-objective function, and the linear weighting method is used to achieve multi-objective optimization. The constraints of the multi-objective optimization are to ensure that each time slot is allocated and each node is allocated at least one time slot.

8. The method for allocating time slots for spatial multiplexing based on the conflict matrix of underwater acoustic channels according to claim 1, characterized in that: In the fourth step, the coding mapping method of the search sample space is as follows: the time slot allocation result is represented by the time slot allocation matrix T, and it is mapped to the sample vector in the form of binary coding: assuming that there are M time slots allocated to N nodes, then create an N*M matrix, the elements in the matrix are composed of 0 or 1, and map the matrix to the sample vector column by column.

9. A computer system comprising a memory, a processor, and a computer program / instruction stored in the memory and executable on the processor, characterized in that: When the computer program / instructions are executed by the processor, the steps of the method for spatial multiplexing time slot allocation based on the underwater acoustic channel conflict matrix according to any one of claims 1 to 8 are implemented.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by the processor, the steps of the method for spatial multiplexing time slot allocation based on the underwater acoustic channel conflict matrix according to any one of claims 1 to 8 are implemented.

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