Decision information timeliness evaluation method in communication-control combined system

Abstract

The invention discloses a decision information timeliness evaluation method in a communication-control combined system, and the method comprises the steps: constructing the communication-control combined system composed of a communication module and a decision module based on the decision timeliness requirement of a communication system and the characteristic that the communication module and the decision module are independent from each other; according to the method, a new performance index decision age AoD is constructed based on an information transmission path of the system and a traditional information timeliness performance index AoI, and the new performance index decision age AoD is used for evaluating the timeliness of a decision; in a communication-control combined system composed of a traditional communication system and a random decision system, an average peak AoD index is obtained in the communication-control combined system by utilizing a splitting calculation mode based on the definition of AoD and around the particularity of part of decisions in the system. Based on the index, the decision information timeliness performance in the system can be evaluated while the decision behavior characteristics are considered.

Description

Technical Field

[0001] The present invention relates to the field of wireless network communication and network performance evaluation, and in particular to a method for evaluating the timeliness of decision information in a communication-control joint system. Background Art

[0002] Age of Information (AoI) is an indicator used to evaluate the freshness of system information. It is defined as the time since the last information received by the system at the current moment was generated. It is of great significance for evaluating the immediacy of the system. The freshness of system information is crucial to the real-time monitoring system and status update system of the Internet of Things. If the destination receives outdated information, the accuracy and reliability of the system's decision-making may be reduced. In reality, the key to information timeliness lies in the information timeliness of decision-related information. If the data packet transmitted in a communication system is not used and played a role by the subsequent decision-making system, its information timeliness is not necessary to be taken seriously. Therefore, it is very important to characterize the timeliness of decision information, but the current existing indicators (such as AoI) are difficult to achieve accurate evaluation of the timeliness of decision information. Therefore, it is very important to propose a method for characterizing the timeliness of decision information and a method for theoretically evaluating the timeliness of decision information. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a method for evaluating the timeliness of decision information in a communication-control joint system, aiming at a system in which communication and decision-making modules interact with each other. Taking the joint system established on the principle that communication and decision-making modules are independent of each other as the analysis model, a method for characterizing the timeliness of decisions is proposed, and a method for theoretically evaluating the timeliness of decisions is proposed.

[0004] Technical solution: To achieve the above-mentioned invention object, the present invention proposes a method for evaluating the timeliness of decision information in a communication-control joint system, which comprises the following steps:

[0005] (1) Establish a communication model based on queuing theory to form a communication subsystem; establish a random sampling module and a decision calculation module to form a decision subsystem; the two are combined in an independent form to form a communication-control joint system;

[0006] (2) Based on the definition of information age AoI, the indicator of decision age AoD is constructed;

[0007] (3) according to the definition of AoD in step (2), determine the effective decision and special packets, and obtain the representation of the average peak AoD in the communication-control joint system through split calculation;

[0008] (4) The decision timeliness in the communication-control joint system is simulated and evaluated based on the representation of the average peak AoD.

[0009] Furthermore, in step (1), in the communication-control joint system, the communication subsystem adopts a G / G / 1 queuing model, with an arrival rate of λ, a service rate of μ, a first-come-first-served principle, and a buffer set to infinity; the decision subsystem consists of a random sampling module and a calculation module, and the random sampling module according to Poisson sampling is adopted, and its sampling rate is ν, and the calculation duration of the calculation module is fixed, the duration is σ.

[0010] Furthermore, in step (1), in the communication-control joint system, the newly arrived data packet first enters the communication subsystem, and the decision subsystem uses the random sampling module to make a random decision based on the latest data packet received by the communication subsystem. The data packets successfully sampled for decision-making are then forwarded to the calculation module, and the calculation module performs calculations in turn according to the contents of these data packets. After each calculation is completed, a final decision is made based on the calculation results.

[0011] Furthermore, in step (1), in the communication-control joint system, the generation time of the kth data packet in the system is denoted as t k The transmission completion time is denoted as t k '; The sampling time of the jth decision is recorded as τ j , from τ j The completion time of the started calculation is τ j '.

[0012] Furthermore, in step (2), the decision age AoD in the communication-control joint system is defined as the time difference between the current time t and the generation time of the latest data packet that completed the decision, expressed as:

[0013] Δ D (t) = tU(t)

[0014] Where t is the current time, U(t) is the generation time of the latest data packet that has completed the decision, and the index of the packet is N U (t), then Indicates that the index is N U (t) is the time when the data packet is generated:

[0015]

[0016] At the current time t, N U (t) is expressed as:

[0017] N U (t) = f(max{j|τ j ′≤t})

[0018] In the above formula, f(·) represents the mapping relationship between the j-th decision in the system and the index k of the data packet used for the decision, τ j′ represents the time when the calculation of the j-th decision is completed.

[0019] Furthermore, in step (3), in the communication-control joint system, the first decision of the data packet transmitted in the system is determined to be a valid decision, and its index is represented by h n ; Determine the package that successfully completes the decision in the system as a special package, and its index is represented by g n .

[0020] Furthermore, in step (3), the peak AoD is expressed as:

[0021] A D (k) = τ j '-t m

[0022] In the above formula, A D (k) represents the peak AoD value generated by the jth effective decision made on the kth data packet, and the kth data packet is a special packet, m is the index of the data packet used in the j-1th decision, and t m The time when the data packet is generated.

[0023] Furthermore, in step (3), by D (k) is split and the expression for obtaining the average peak AoD is:

[0024]

[0025] in, represents the mean of the random variable, represents the average peak AoD, Represents an effective decision h n The calculation time of Represents an effective decision h n The waiting time for the special packet g n-1 +1 Departure Time to the time interval between Indicates the h n The decision moment of the second decision; Indicates special package g n +1 for the time of isolation; Indicates special package g n The time a signal stays in the communication subsystem.

[0026] Furthermore, the result of the split calculation of the average peak AoD in step (3) is:

[0027]

[0028] In the above formula, ps (y) is the time period Y of length y in the communication-control joint system k The probability of sampling on is p s (y) = 1-e -νy ;

[0029] p t (t) is the time period T with a length of t k The time between the k+1th packets is Y k+1 The probability of sampling on is

[0030] Among them, X k is the arrival time interval between two consecutive data packets; S k is the service time of data packet k; The probability density function of the middle isolation time of the G / G / 1 queue model; is the probability density function of the system residence time in the G / G / 1 queue model; is the probability density function of service time in the G / G / 1 queue model; and They are the probability density function and distribution function of the inter-arrival time in the G / G / 1 queue model respectively.

[0031] Furthermore, in step (4), the expression of the average peak AoD is obtained in the communication-control joint system with the communication subsystem being M / M / 1:

[0032]

[0033] According to the established communication-control joint system model and the definition of AoD, a simulation curve of the average peak AoD is obtained in the communication-control joint system with the communication subsystem M / M / 1 to verify the accuracy of the above formula. In the communication-control joint system, different variation curves of the average peak AoD are obtained under different arrival rates, service rates and sampling frequencies, and the timeliness of system decisions under different conditions is evaluated.

[0034] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0035] Based on the impact of decision-making on the timeliness of information in communication systems in reality, the present invention establishes a new communication-control joint system from the perspective of decision-making and proposes a new method for evaluating the timeliness of decision-making. This method can evaluate the timeliness of decision-making more comprehensively and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of a communication-control combined system in the present invention;

[0037] Figure 2 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0038] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0039] like Figure 2 As shown, the present invention proposes a method for evaluating the timeliness of decision information in a communication-control joint system, the method comprising the following steps:

[0040] (1) Establish a communication model based on queuing theory to form a communication subsystem; establish a random sampling module and a decision calculation module to form a decision subsystem; the two are combined in an independent form to form a communication-control joint system;

[0041] (2) Based on the definition of information age AoI, the indicator of decision age AoD is constructed;

[0042] (3) according to the definition of AoD in step (2), determine the effective decision and special packets, and obtain the representation of the average peak AoD in the communication-control joint system through split calculation;

[0043] (4) The decision timeliness in the communication-control joint system is simulated and evaluated based on the representation of the average peak AoD.

[0044] Furthermore, in step (1), in the communication-control joint system, the communication subsystem adopts a G / G / 1 queuing model, with an arrival rate of λ, a service rate of μ, a first-come-first-served principle, and a buffer set to infinity; the decision subsystem consists of a random sampling module and a calculation module, and the random sampling module according to Poisson sampling is adopted, and its sampling rate is ν, and the calculation duration of the calculation module is fixed, the duration is σ.

[0045] Furthermore, in step (1), in the communication-control joint system, the newly arrived data packet first enters the communication subsystem, and the decision subsystem uses the random sampling module to make a random decision based on the latest data packet received by the communication subsystem. The data packets successfully sampled for decision-making are then forwarded to the calculation module, and the calculation module performs calculations in turn according to the contents of these data packets. After each calculation is completed, a final decision is made based on the calculation results.

[0046] Furthermore, in step (1), in the communication-control joint system, the generation time of the kth data packet in the system is denoted as t kThe transmission completion time is denoted as t k '; The sampling time of the jth decision is recorded as τ j , from τ j The completion time of the started calculation is τ j '.

[0047] Furthermore, in step (2), the decision age AoD in the communication-control joint system is defined as the time difference between the current time t and the generation time of the latest data packet that completed the decision, expressed as:

[0048] Δ D (t) = tU(t)

[0049] Where t is the current time, U(t) is the generation time of the latest data packet that has completed the decision, and the index of the packet is N U (t), then Indicates that the index is N U (t) is the time when the data packet is generated:

[0050]

[0051] At the current time t, N U (t) is expressed as:

[0052] N U (t) = f(max{j|τ j ′≤t})

[0053] In the above formula, f(·) represents the mapping relationship between the j-th decision in the system and the index k of the data packet used for the decision, τ j ′ represents the time when the calculation of the j-th decision is completed.

[0054] Furthermore, in step (3), in the communication-control joint system, the first decision of the data packet transmitted in the system is determined to be a valid decision, and its index is represented by h n ; Determine the package that successfully completes the decision in the system as a special package, and its index is represented by g n .

[0055] Furthermore, in step (3), the peak AoD is expressed as:

[0056] A D (k) = τ j '-t m

[0057] In the above formula, A D (k) represents the peak AoD value generated by the jth effective decision made on the kth data packet, and the kth data packet is a special packet, m is the index of the data packet used in the j-1th decision, and tm The time when the data packet is generated.

[0058] Furthermore, in step (3), by D (k) is split and the expression for obtaining the average peak AoD is:

[0059]

[0060] in, represents the mean of the random variable, represents the average peak AoD, Represents an effective decision h n The calculation time of Represents an effective decision h n The waiting time for the special packet g n-1 +1 Departure Time to the time interval between Indicates the h n The decision moment of the second decision; Indicates special package g n +1 for the time of isolation; Indicates special package g n The time a signal stays in the communication subsystem.

[0061] Furthermore, the result of the split calculation of the average peak AoD in step (3) is:

[0062]

[0063] In the above formula, p s (y) is the time period Y of length y in the communication-control joint system k The probability of sampling on is p s (y) = 1-e -νy ;

[0064] p t (t) is the time period T with a length of t k The time between the k+1th packets is Y k+1 The probability of sampling on is

[0065] Among them, X k is the arrival time interval between two consecutive data packets; S k is the service time of data packet k; The probability density function of the middle isolation time of the G / G / 1 queue model; is the probability density function of the system residence time in the G / G / 1 queue model; is the probability density function of service time in the G / G / 1 queue model; and They are the probability density function and distribution function of the inter-arrival time in the G / G / 1 queue model respectively.

[0066] Furthermore, in step (4), the expression of the average peak AoD is obtained in the communication-control joint system with the communication subsystem being M / M / 1:

[0067]

[0068] According to the established communication-control joint system model and the definition of AoD, a simulation curve of the average peak AoD is obtained in the communication-control joint system with the communication subsystem M / M / 1 to verify the accuracy of the above formula. In the communication-control joint system, different variation curves of the average peak AoD are obtained under different arrival rates, service rates and sampling frequencies, and the timeliness of system decisions under different conditions is evaluated.

Claims

1. A method for evaluating the timeliness of decision information in a communication-control joint system, characterized in that: The method comprises the following steps: (1) Establish a communication model based on queuing theory to form a communication subsystem; establish a random sampling module and a decision calculation module to form a decision subsystem; the two are combined in an independent form to form a communication-control joint system; (2) Based on the definition of information age AoI, the indicator of decision age AoD is constructed; (3) according to the definition of AoD in step (2), determine the effective decision and special packets, and obtain the representation of the average peak AoD in the communication-control joint system through split calculation; (4) The decision timeliness in the communication-control joint system is simulated and evaluated based on the representation of the average peak AoD.

2. A method for evaluating the timeliness of decision information in a communication-control joint system according to claim 1, characterized in that: In step (1), in the communication-control joint system, the communication subsystem adopts a G / G / 1 queuing model, with an arrival rate of λ, a service rate of μ, a first-come-first-served principle, and a buffer set to be infinite; the decision subsystem consists of a random sampling module and a calculation module, and a random sampling module based on Poisson sampling is adopted, with a sampling rate of ν, and a calculation module with a fixed calculation duration of σ.

3. The method for evaluating the timeliness of decision information in a communication-control joint system according to claim 2, characterized in that: In step (1), in the communication-control joint system, the newly arrived data packet first enters the communication subsystem, and the decision subsystem uses the random sampling module to make a random decision based on the latest data packet received by the communication subsystem. The data packets successfully sampled for decision-making are then forwarded to the calculation module, which performs calculations in turn based on the contents of these data packets. After each calculation is completed, the final decision is made based on the calculation results.

4. The method for evaluating the timeliness of decision information in a communication-control joint system according to claim 3, characterized in that: In step (1), in the communication-control joint system, the generation time of the kth data packet in the system is denoted as t k The transmission completion time is denoted as t k '; The sampling time of the jth decision is recorded as τ j , from τ j The completion time of the started calculation is τ j '.

5. The method for evaluating the timeliness of decision information in a communication-control joint system according to claim 2, characterized in that: In step (2), the decision age AoD in the communication-control joint system is defined as the time difference between the current time t and the generation time of the latest data packet that completed the decision, expressed as: Δ D (t)=t-U(t) Where t is the current time, U(t) is the generation time of the latest data packet that has completed the decision, and the index of the packet is N U (t), then t NU(t) Indicates that the index is N U (t) is the time when the data packet is generated: At the current time t, N U (t) is expressed as: N U (t)=f(max{j|τ j ′≤t}) In the above formula, f(·) represents the mapping relationship between the j-th decision in the system and the index k of the data packet used for the decision, τ j ′ represents the time when the calculation of the j-th decision is completed.

6. A method for evaluating the timeliness of decision information in a communication-control joint system according to claim 5, characterized in that: In step (3), in the communication-control joint system, the first decision of the data packet transmitted in the system is determined to be a valid decision, and its index is represented by h n ; Determine the package that successfully completes the decision in the system as a special package, and its index is represented by g n .

7. A method for evaluating the timeliness of decision information in a communication-control joint system according to claim 6, characterized in that: In step (3), the peak AoD is expressed as: A D (k)=τ j '-t m In the above formula, A D (k) represents the peak AoD value generated by the jth effective decision made on the kth data packet, and the kth data packet is a special packet, m is the index of the data packet used in the j-1th decision, and t m The time when the data packet is generated.

8. The method for evaluating the timeliness of decision information in a communication-control joint system according to claim 7, characterized in that: In step (3), by D (k) is split and the expression for obtaining the average peak AoD is: in, represents the mean of the random variable, represents the average peak AoD, Represents an effective decision h n The calculation time of Represents an effective decision h n The waiting time of the special package g n-1 +1 Departure Time to the time interval between Indicates the h n The decision moment of the second decision; Indicates special package g n +1 for the time of isolation; Indicates special package g n The time a signal stays in the communication subsystem.

9. A method for evaluating the timeliness of decision information in a communication-control joint system according to claim 8, characterized in that: The result of the split calculation of the average peak AoD in step (3) is: In the above formula, p s (y) is the time period Y of length y in the communication-control joint system k The probability of sampling on is p s (y) = 1-e -νy ; p t (t) is the time period T with a length of t k The time between the k+1th packets is Y k+1 The probability of sampling on is Among them, X k is the arrival time interval between two consecutive data packets; S k is the service time of data packet k; The probability density function of the middle isolation time of the G / G / 1 queue model; is the probability density function of the system residence time in the G / G / 1 queue model; is the probability density function of service time in the G / G / 1 queue model; and They are the probability density function and distribution function of the inter-arrival time in the G / G / 1 queue model respectively.

10. The method for evaluating the timeliness of decision information in a communication-control joint system according to claim 7, characterized in that: In step (4), the expression of the average peak AoD is obtained in the communication-control joint system with the communication subsystem being M / M / 1: According to the established communication-control joint system model and the definition of AoD, a simulation curve of the average peak AoD is obtained in the communication-control joint system with the communication subsystem M / M / 1 to verify the accuracy of the above formula. In the communication-control joint system, different variation curves of the average peak AoD are obtained under different arrival rates, service rates and sampling frequencies, and the timeliness of system decisions under different conditions is evaluated.

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