CN116996943A

CN116996943A - Method, device, electronic equipment and medium for accessing system to network

Info

Publication number: CN116996943A
Application number: CN202310803616.1A
Authority: CN
Inventors: 王莹; 赵俊伟; 晏英杰; 费子轩; 王雪
Original assignee: Beijing University of Posts and Telecommunications
Current assignee: Beijing University of Posts and Telecommunications
Priority date: 2023-06-30
Filing date: 2023-06-30
Publication date: 2023-11-03

Abstract

The application discloses a method, a device, electronic equipment and a medium for accessing a system into a network. In the application, the first part of network resources in all network resources can be allocated for the NCS system, and the first part of network resources are the minimum network resources required on the premise of meeting the stability of the NCS system; allocating a second part of network resources in all network resources for the RMS system, wherein the second part of network resources are network resources required for maximizing the user experience quality on the premise that the minimum data transmission of the RMS system can be met; based on the channel state information, the NCS system and the RMS system are connected into an industrial Internet system. By applying the technical scheme of the application, the system access strategies of the NCS and the RMS can be reasonably configured by optimizing the network resources of the NCS and the RMS in the industrial Internet system in the coexistence scene of the NCS and the RMS, so that the quality of experience of the RMS system is maximized on the premise of ensuring the control stability of each NCS system and the minimum throughput of RMS users.

Description

Method, device, electronic equipment and medium for accessing system to network

Technical Field

The present application relates to a communication network configuration technology, and in particular, to a method, an apparatus, an electronic device, and a medium for accessing a system to a network.

Background

Related art in the industrial internet, real-time monitoring systems (Real-time Monitoring Systems, RMSs) and network control systems (Networked Control Systems, NCSs) are of paramount importance.

The RMS system is the basis of the industrial Internet, acquires global information of an industrial platform in real time through a camera device, and provides information support for different industrial applications. The NCS system is the key of the industrial Internet, and the efficient implementation of industrial automation is ensured by information exchange between the network of system components (sensors, controllers, actuators and the like).

However, communication guarantee in the coexistence scenario of RMS and NCS information flows faces great difficulties due to the great difference. In particular, the information stream of RMS is typically a media data stream including video, audio, image, etc. having a characteristic of a large data amount for a long time, and the throughput of the communication system is highly demanded. The traffic in the NCS is generally a periodic small data packet, and the requirements on timeliness and reliability of the communication system are high.

Therefore, how to design an efficient transmission of an industrial internet system comprising an RMS system and an NCS system over a communication network becomes a problem to be solved by those skilled in the art.

Disclosure of Invention

The embodiment of the application provides a method, a device, electronic equipment and a medium for accessing a system into a network. Thus solving the problem that none of the related art has been able to efficiently transmit an industrial internet system comprising an RMS system and an NCS system over a communication network.

According to an aspect of the embodiment of the present application, a method for accessing a system to a network is provided, and the method is applied to an industrial internet system including a real-time monitoring system RMS and a network control system NCS, and includes:

allocating a first part of network resources in all network resources for the NCS system, wherein the first part of network resources are minimum network resources required on the premise of meeting the stability of the NCS system;

allocating a second part of network resources in all network resources for the RMS system, wherein the second part of network resources are network resources required for maximizing user experience quality on the premise of meeting the minimum data transmission of the RMS system;

based on channel state information, the NCS system and the RMS system are accessed into the industrial Internet system.

Optionally, in another embodiment of the above method according to the present application, the allocating a first part of network resources among all network resources to the NCS system includes:

Detecting timeliness of data transmission in the NCS system based on a dynamic change value of information age AoI; detecting the success rate of data transmission of the NCS system in a preset time slot based on the packet loss rate;

and taking the network resource which can enable the timeliness to meet the first minimum condition and the data transmission success rate to meet the second minimum condition as the first part of network resource.

Optionally, in another embodiment of the above method according to the present application, the step of enabling the timeliness to meet a first minimum condition comprises:

acquiring an adoption period of an industrial information stream acquired by a sensor in the NCS system, and calculating a first AoI dynamic change value corresponding to the sensor based on the sampling period and the industrial information stream which is received by the sensor recently;

updating a second AoI dynamic change value corresponding to a controller in the NCS system based on the first AoI dynamic change value corresponding to the sensor;

updating a third AoI dynamic change value corresponding to an actuator in the NCS system based on a second AoI dynamic change value corresponding to the controller;

and if the third AoI dynamic change value is smaller than the maximum AoI dynamic change value allowed by the NCS system, determining that the timeliness meets the first minimum condition.

Optionally, in another embodiment of the above method according to the present application, the third AoI dynamic change value is determined to be smaller than the maximum AoI dynamic change value allowed by the NCS system by the following formula:

wherein A is _a，k (N) is the third AoI dynamic change value of the kth sensor in time slot N, and K and N are positive integers.

Optionally, in another embodiment of the above method according to the present application, said allocating a second part of the total network resources to the RMS system includes:

determining a minimum data transmission standard of the RMS system based on a minimum average data throughput of the RMS system;

and taking network resources capable of maximizing the user experience quality as the second part of network resources based on the experience quality QoE.

Optionally, in another embodiment of the above method according to the present application, the accessing the NCS system and the RMS system into the industrial internet system based on channel state information includes:

if the current imperfect channel state information is determined, an offline access strategy based on historical channel statistical information is selected to access the NCS system and the RMS system into the industrial Internet system; or alternatively, the first and second heat exchangers may be,

If the current perfect channel state information is determined, an online access strategy based on the current channel state information is selected to access the NCS system and the RMS system to the industrial Internet system;

wherein, the perfect channel state information is that the NCS system and the RMS system can obtain the channel state information of the current time slot when each time slot starts;

the imperfect channel state information is channel state information of the current time slot which cannot be obtained by the NCS system and the RMS system.

According to a further aspect of the embodiment of the present application, there is provided a device for accessing a system to a network, which is applied to an industrial internet system including a real-time monitoring system RMS and a network control system NCS, the device comprising:

a first allocation module configured to allocate a first part of network resources among all network resources for the NCS system, the first part of network resources being minimum network resources required on the premise that stability of the NCS system can be satisfied;

the second allocation module is configured to allocate a second part of network resources in all network resources to the RMS system, wherein the second part of network resources are network resources required for maximizing the user experience quality on the premise that the minimum data transmission of the RMS system can be met;

An access module configured to access the NCS system and the RMS system into the industrial internet system based on channel state information.

According to still another aspect of an embodiment of the present application, there is provided an electronic apparatus including:

a memory for storing executable instructions; and

and the display is used for executing the executable instructions with the memory so as to finish the operation of the method for accessing the network by any system.

According to yet another aspect of an embodiment of the present application, there is provided a computer readable storage medium storing computer readable instructions that when executed perform the operations of any of the above methods for accessing a network by a system.

In the application, the first part of network resources in all network resources can be allocated for the NCS system, and the first part of network resources are the minimum network resources required on the premise of meeting the stability of the NCS system; allocating a second part of network resources in all network resources for the RMS system, wherein the second part of network resources are network resources required for maximizing the user experience quality on the premise that the minimum data transmission of the RMS system can be met; based on the channel state information, the NCS system and the RMS system are connected into an industrial Internet system. By applying the technical scheme of the application, the system access strategies of the NCS and the RMS can be reasonably configured by optimizing the network resources of the NCS and the RMS in the industrial Internet system in the coexistence scene of the NCS and the RMS, so that the quality of experience of the RMS system is maximized on the premise of ensuring the control stability of each NCS system and the minimum throughput of RMS users.

The technical scheme of the application is further described in detail through the drawings and the embodiments.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description, serve to explain the principles of the application.

The application may be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic diagram of a method for accessing a system to a network according to the present application;

FIG. 2 is a schematic diagram of a system architecture of an industrial Internet system including a real-time monitoring system RMS and a network control system NCS according to the present application;

fig. 3 is a schematic diagram of channel failure transmission of a wireless channel model according to the present application;

fig. 4 is a schematic structural diagram of an electronic device according to the present application;

fig. 5 is a schematic structural diagram of an electronic device according to the present application.

Detailed Description

Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless it is specifically stated otherwise.

Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description.

The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the application, its application, or uses.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

In addition, the technical solutions of the embodiments of the present application may be combined with each other, but it is necessary to be based on the fact that those skilled in the art can implement the technical solutions, and when the technical solutions are contradictory or cannot be implemented, the combination of the technical solutions should be considered as not existing, and not falling within the scope of protection claimed by the present application.

It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present application are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicators are correspondingly changed.

A method for performing system access to a network according to an exemplary embodiment of the present application is described below with reference to fig. 1-2. It should be noted that the following application scenarios are only shown for facilitating understanding of the spirit and principles of the present application, and embodiments of the present application are not limited in this respect. Rather, embodiments of the application may be applied to any scenario where applicable.

The application also provides a method, a device, electronic equipment and a medium for accessing the system into the network.

Fig. 1 schematically shows a flow diagram of a method of accessing a network by a system according to an embodiment of the application. As shown in fig. 1, the method is applied to an industrial internet system comprising a real-time monitoring system RMS and a network control system NCS, and comprises the following steps:

s101, a first part of network resources in all network resources can be allocated for the NCS system, wherein the first part of network resources are minimum network resources required on the premise of meeting the stability of the NCS system.

S102, distributing a second part of network resources in all network resources for the RMS system, wherein the second part of network resources are network resources required for maximizing the user experience quality on the premise that the minimum data transmission of the RMS system can be met.

And S103, accessing the NCS system and the RMS system into an industrial Internet system based on the channel state information.

In the related art, a real-time monitoring RMS system is the basis of an industrial Internet, global information of an industrial platform is obtained in real time through a camera device, and information support is provided for different industrial applications. Network control NCS system is the key of industrial Internet, and the efficient realization of industrial automation is ensured by information exchange between the network of system components (sensors, controllers, actuators and the like).

In one approach, since the industrial internet system is a wireless communication system, the use of the wireless communication system can complicate the analysis and design of the NCS system. It will be appreciated that conventional control systems are based on many ideal assumptions, such as synchronous control, non-delayed sensing and driving, etc., which must be reevaluated before application to the NCS.

In particular, the influence of transmission delay and packet loss of a wireless communication system on the stability of an NCS system is mainly required to be solved. In addition, increasing the NCS system sensor sampling rate is a common solution to address the challenges described above. The scheme ensures that the system can acquire more latest system information, and effectively ensures the stability of the control system. However, as the number of NCS systems increases, high sampling rates place a significant burden on the network. Because of the limited wireless channel resources, the transmission of a large amount of system data causes network congestion, which leads to higher time delay and packet loss, and conversely, the overall performance of the system is deteriorated.

In another approach, the low data rate and data rate fluctuations of the RMS system can result in a significant impact on the quality of experience of the RMS system due to limited network resources and rapid changes in channel conditions.

In view of the above problems, the present application proposes a method for accessing a network by a system, which is aimed at measuring the timeliness of the information flow in the NCS by adopting the information age (Age of Information, aoI) technology. Thereby guaranteeing long-term stability of the NCS system accordingly. On the other hand, for RMS systems, the quality of experience of devices in RMS may be measured based on QoE (Quality of Experience) techniques, for example, in the manner of mean opinion score (Mean Opinion Score, MOS). At the same time, minimum average throughput is introduced to ensure the quality of experience of the lowest data transmission for the RMS user.

Based on the above thought, the specific scheme of the application is that in the industrial Internet system aiming at the NCS and RMS coexistence scene, the system access strategy of the NCS and the RMS is reasonably configured by optimizing the network resources of the NCS and the RMS, thereby maximizing the experience quality of the RMS system on the premise of ensuring the control stability of each NCS system and the minimum throughput of the RMS user.

Further, the present application is specifically described herein in connection with further embodiments:

As shown in fig. 2, an industrial internet system comprising a real-time monitoring system RMS and a network control system NCS is proposed in the present application.

Wherein the RMS system comprises the following components in a set wayThe M independent monitoring devices of the industrial system are accessed to the base station through wireless channels and monitoring information is sent to the base station terminal, so that real-time monitoring of the industrial system is realized.

The NCS system comprises the collection asIs provided. Each control system corresponds to a piece of mechanical equipment, a sensor for measuring the state of the mechanical equipment and an actuator for controlling the action of the equipment.

Furthermore, in the NCS system, the sensor needs to periodically sample and collect the status information of the industrial platform, and the sampling period is T _k And through the uplink radio linkTransmitting the status information to the base station; and the remote controller at the base station side calculates and executes the action according to the state information and sends the control information to the executor for execution through a downlink wireless link. The NCS system shares W orthogonal subchannels with the RMS system.

As an example, the sensor, the actuator, the monitoring device access the base station and transmit data in an orthogonal frequency division multiple access manner. The system time is divided into N time slots, denoted asThe time for each slot is assumed to be 1.

In a first aspect, for a wireless channel model:

for the wireless communication model, consider a point-to-point single-hop communication link based on a block fading channel model. That is, the channel power gain remains constant for a fixed duration of the channel coherence block length, varying independently between different blocks. Let us assume that the channel coherence block length is one slot. The channel gain for time slot n is denoted as h (n). { h (1), h (2), …, h (n), … } are random variable sequences independently and uniformly distributed inDistributed in the form of h->Is->Is a tight subset of (a).

Further, the present application subsequently considers two cases:

1) Perfect channel state information, i.e. the system can obtain accurate channel state information of the current time slot at the beginning of each time slot;

2) Imperfect channel state information, i.e. the system knows only the distribution f of channel state information _h But cannot acquire accurate channel state information of each time slot.

Further, for ease of calculation and description, without loss of generality, it is assumed that H contains I non-0 discrete variables,h ₁ <h ₂ <…<h _I ，p(H＝h _i )＝p _i ，/>

for NCS systems:

the embodiment of the application needs to consider the uplink between the sensor and the controller and the downlink between the controller and the actuator of the NCS system respectively.

For the uplink, the sensor has a simple structure and limited power consumption, and cannot perform complex data transmission operations. Thus, it is assumed that the sensor can only access the network transmission status information at the time of sampling.

For the downlink, since the controller is disposed at the base station side, the controller may repeat transmission of control information to the executor until transmission is successful or the maximum number of retransmissions H considering that the downlink employs a hybrid automatic repeat request (Hybrid Automatic Repeat Request, HARQ) transmission mechanism. In addition, to ensure timeliness of NCS system information flow, the controller processes and generates control information immediately after receiving status information from the sensors, and sends the control information to the actuator in real time.

By way of example, taking control system k as an example, the 0-1 variables α, β are used to represent the scheduling policy for the control system uplink and downlink, respectively. Alpha _k,n =1 means that sensor k transmits industrial equipment status information in time slot n, otherwise α _k,n ＝0；

β _k,n =1 means that controller k transmits control information in slot n, otherwise β _k,n ＝0。

The variables a and b of 0-1 are used to respectively indicate whether the uplink and downlink information of the control system is successfully transmitted.

a _k,n =1 indicates that the industrial equipment status information transmitted by sensor k in time slot n is successfully transmitted, otherwise a _k,n ＝0；b _k,n =1 means that the control information transmitted by the controller k in the time slot n is successfully transmitted, otherwise β _k,n ＝0。

For NCS systemIn general, because the data packet of the information flow is smaller, it is assumed that the state information data packet and the control information data packet of the information flow are transmitted in one time slot, otherwise, the data packet is failed to be transmitted to generate packet loss. Packet losses of the uplink and the downlink are independent. The sensor transmission power is P _s,k The size of the status information data packet is L _s,k The method comprises the steps of carrying out a first treatment on the surface of the The transmission power of the controller is P _c,k The control information data packet size is L _c,k 。

Therefore, according to shannon's channel formula, the channel state required for successful transmission of state information isThe channel state required by the successful transmission of the control information is +.>Therefore, according to the channel model in 2.1, the probability of failure of the state information transmission is:

the probability of failure of control information transmission is:

furthermore, the embodiment of the application can also utilize the related concept of AoI to measure the timeliness of the NCS system information flow. Respectively using A _s (n),A _c (n),A _a (n) (i.e., first AoI dynamic change value, second AoI dynamic change value, third AoI dynamic change value, respectively) to represent AoI information flow at sensor, controller, actuator at time slot n.

In one mode, the sensor periodically collects the status information of the industrial platform, and the sampling period is T _k . The sensor obtains the latest information flow after sampling, A _s Becomes 1, otherwise A _s Increasing with time. The dynamic change value of the information flow AoI at the sensor can be expressed as:

next, after successful receipt of the new state information, the information flow AoI at the controller becomes AoI of the state information current, a _s +1, otherwise it increases with increasing time. Thus, the AoI dynamic change value of the information flow at the controller can be expressed as:

finally, after the actuator successfully receives the new information, the information flow AoI at the actuator becomes AoI of the current control information, i.e., A _c +1, otherwise it increases with increasing time. Thus, the AoI dynamic change value of the information flow at the actuator can be expressed as:

to ensure stability of the NCS system, the third AoI dynamic change value of the information flow at the actuator should be smaller than the maximum dynamic change value allowed by the NCS systemNamely:

η _k indicating the stability requirement of the kth NCS system, then for the kth NCS system,

in a second aspect, for an RMS system,

the embodiment of the application can use the variable mu of 0-1 to represent the scheduling strategy of the monitoring equipment. Without loss of generality, taking monitoring device m as an example, μ _m，n =1 indicates its timeSlot n transmits data, otherwise mu _m，n =0. The throughput of the monitoring device m in time slot n is therefore:

R _m (n)＝μ _m,n Blog ₂ (1+P _m ·h _m (n)), (8)

wherein the bandwidth of the B sub-channel, P _m Data transmission power. Thus, the average throughput of the monitoring device m is:

the application adopts the MOS value as an index and utilizes the long-term average throughput of the RMS equipment to measure the quality of experience of the RMS system.

Wherein, eta, lambda, omega ₁ ,ω ₂ Is constant, V represents the motion parameter of the device (assuming the device is stationary, V is constant), R _m To monitor the average throughput of the device.

To ensure the minimum quality of experience of the monitoring devices, each monitoring device must be able to smoothly transmit the message stream with the minimum transmission requirement (e.g., the minimum code rate), and it is required to satisfy:

wherein, the liquid crystal display device comprises a liquid crystal display device,to ensure the minimum average throughput required for the streaming of the information.

From the above, the application aims to maximize the long-term average experience quality of the RMS system by jointly optimizing the NCS system sensor, the controller access scheduling strategies alpha, beta and the RMS monitoring equipment scheduling strategy mu under the premise of ensuring the stability of the NCS system and the minimum transmission requirement of the RMS system equipment.

Further, the optimization problem can be expressed as:

wherein (12 a) - (12 d) are access restrictions, and any time slot device accesses one sub-channel at most, and the number of devices accessed by the system simultaneously does not exceed the number of sub-channels. (12 e) monitoring the device data transmission requirement limit for the RMS system. (12 f) is NCS system stability limit.

Solving problem P is very challenging. On the one hand, the problem P is a long-term random optimization problem, and the acquisition of the global optimal solution needs to acquire accurate wireless state information of each time slot in advance. Because of the time-varying nature of the wireless channel, accurate channel state prior information cannot be obtained.

Therefore, it is not practical to solve the globally optimal interpretation of problem P. On the other hand, according to formulas (8) and (9), the variables α and β are coupled to each other, and a cannot be obtained _a Closed expression of (2). Therefore, the conventional optimization method is not applicable when solving the problem P.

To address the challenges described above, a phased optimization approach is proposed: 1) Firstly, ensuring the stability requirement of an NCS system by using the minimum network resources, and acquiring the access scheme of a sensor and a controller of the NCS system; 2) And maximizing the experience quality of the RMS system on the premise that the residual resources meet the minimum transmission requirement of the RMS equipment, and acquiring an access scheme of the RMS system.

Further, aiming at two situations of channel state information acquisition at a base station, non-perfect channel state information and perfect channel state information, the application respectively provides an offline access strategy based on historical channel statistical information and an online access strategy based on current channel state information.

In one mode, taking the kth NCS system as an example, the stability of the NCS system is analyzed, and a solution idea is provided for the establishment of an access strategy of an NCS sensor and a controller.

The sensor is often oversampled by 10-20 times in digital control to ensure extremely high stability and better smoothness of the control system. But this mechanism can greatly burden the communication network and reduce the radio resource utilization. As the degree of automation of industrial control systems increases, the contradiction between the drastically increasing number of sensors and the limited wireless channel becomes increasingly prominent. For the above contradictions, some documents state that: failure of the information flow in the communication domain does not necessarily lead to instability of the control domain.

Based on the above conclusion, the NCS stability limit is translated into a periodic sampling and transmission of the sensor: the NCS system information stream transmission fails F times in succession, still can meet its stability requirements.

The transmission of the sensor sampled information from the sensor to the controller to the actuator is defined as one complete transmission of the NCS system information stream. Thus, according to formulas (1) and (2), the probability of failure of complete transmission of an information stream at any one time is:

next, a system failure model as shown in fig. 3 is proposed based on the above-mentioned wireless channel model, single transmission failure probability of the information flow, and markov chain of the present application. And further calculates the probability of system instability when NCS system information stream transmission fails F times in succession based on the model.

Wherein, the liquid crystal display device comprises a liquid crystal display device,and the probability of success of single transmission of the NCS system information flow is obtained. s is(s) _f And F is the number of failure times of information flow transmission, and F is {0, 1. s is(s) ₀ Indicating that the first transmission of the information stream is successful s _F Indicating that the information stream has failed for F consecutive transmissions.

Thus, according to the failure model described above, when the kth NCS system information stream transmission fails F times in succession, the probability of instability thereof can be deduced as follows:

wherein e ₀ ＝(1 0 ... 0)，1＝(1 ... 1)。N＝(I-Q) ^-1 The basic matrix of the absorbing markov chain shown in fig. 3, where I is an identity matrix, Q is a transition probability matrix of all the transients, can be derived from the transition probability P of the markov chain.

According to (7), in the control system, as long as the information flow AoI received at the actuator does not exceedThe system is in a steady state. Thus, in conjunction with the NCS system failure model in fig. 3, the NCS system stability requirements are further translated into: if and only if the NCF system is at s _F In the state, the information flow at the actuator is greater than AoI +.>The system cannot remain stable. Thus, NCS system stability requirements (12 f) can be translated into:

specifically, for imperfect state information, the present application proposes an offline stationary random strategy solution problem P.

It will be appreciated that in the offline state, the NCS system cannot acquire the information flow AoI at the controller and actuator in real time. Therefore, the present application can further translate NCS system stability constraints into minimizing the resource occupation of the NCS system (i.e., minimizing the first part of network resources) while meeting NCS system stability requirements:

every τ of kth NCS system _k (τ _k ∈N ^* ) The network transmission information flow is accessed once in a sampling period, and the stability requirement can be still met.

Further, the kth NCS system is still taken as an example. Every τ when the kth NCS system _k When the network is accessed once in a sampling period, according to (3) - (5)The information flow AoI model is shown, the system is at s _F The maximum value of the information flow AoI at the actuator in the state is (F+1) τ _k T _k . In combination with NCS system failure model, pairPerforming the calculation, (12 f) can be further translated into:

wherein (5-18) and (5-19) represent if and only if the NCF system is at s _F In the state, the information flow at the actuator is AoI greater than

Furthermore, the application can combine the access period tau of each NCS system _k T _k The access policy of the NCS system sensor and the controller can be derived. Meanwhile, the available wireless resource condition of the RMS system in each time slot can be obtained. However, in the imperfect channel state information, the system can only obtain statistical information of the channel state, and cannot obtain accurate real-time channel state information. Therefore, the access of the RMS equipment cannot be accurately controlled in real time, and the optimal access probability of the RMS equipment can only be calculated offline.

Specifically, mu is _m The value discretization is defined as the probability that the monitoring device m accesses the network in any time slot. The access strategy of the RMS system is thatRMS system access policy pi _R The average throughput of an RMS device may be expressed as:

wherein, the liquid crystal display device comprises a liquid crystal display device,B _n the amount of communication resources available to the RMS system at time slot n.

Since the access probability, the number of system resources and the system channel state of the monitoring device are mutually independent in any time slot, the average throughput of the RMS device can be further converted into:

wherein, the liquid crystal display device comprises a liquid crystal display device,an average number of channel resources is available to the RMS system.

Thus, in summary of the above analysis, the optimization problem based on a stationary random strategy can be re-expressed as:

where (22 a) - (22 d) are NCS system access and stability limits and (22 e) - (22 g) are RMS system access and individual device transmission requirements limits.

Specifically, for a stationary random strategy, to minimize NCS system resource occupancy under NCS system stability constraints, τ is calculated according to (22 a) - (22 d) _k The optimal values of (2) are:

therefore, the time when the sensors and the controller of each NCS system access the network can be obtained by combining the sampling period of each NCS system. The time for the NCS system sensor to access the network is as follows:

Wherein t is _k J=0, 1,2, … for the initial time of network access by the NCS system.

The time of the NCS system controller accessing the network cannot be directly expressed by a formula because whether the controller information transmission is successful or not and the information retransmission times cannot be determined. Its specific access timeThe description is as follows: when the base station receives the information transmitted by the sensor, the corresponding controller starts to access the network until the control information is transmitted successfully or the maximum retransmission times are reached.

Through the analysis, the resource occupation condition of the NCS system can be obtained, and the radio resource condition which can be occupied by the RMS system in each time slot can be obtained. Thus, the average amount of communication resources available to the RMS system can be found as:

it should be noted that:the value is always greater than 0.

Next, by solving the problem P2, the RMS system access policy pi can be obtained _R 。

For problem P2, its objective function is about μ _m Is (26 a) and (26 b) is a concave function with respect to μ _m (26 c) is a linear constraint with respect to μ _m Is a concave set of (a). Thus, problem P2 is a convex optimization problem. To obtain optimal RMS system access policyKKT condition for problem P2And (5) analyzing. Let->To limit the multiplier associated with condition (26 c), δ to limit the multiplier associated with condition (26 b), the Lagrangian function of (26) may be written as:

The optimal solution of P2 satisfies the KKT condition:

(a) The steady equation:

(b) Original feasibility:

(c) Dual feasibility:

(d) Complementary relaxation:

(e) Complementary relaxation:

further calculation (28 a) ofFor mu _m The deviation derivative can be obtained:

wherein, the liquid crystal display device comprises a liquid crystal display device,/>

according to (28 b),and gamma, omega ₁ ,M,/>Is not negative, thus delta can be obtained according to (29)>0. From (28 e), δ=0 or +.>From the above analysis, it is found that all the KKT conditions in (28) are satisfied:

thus, according to (28 c) and (28 d), it is possible toThe RMS devices are divided into two categories: />Is provided with a device for the control of the apparatus,is a device of (a). For->According to (29):

for the followingAccording to (28 d):

in summary, for any δ >0, the optimal scheduling policy for an rms device is:

furthermore, the application can design the problem P2 solving algorithm 1 as follows:

1: initializing delta _m Value, order

2: initializing delta value to make

3: calculation of mu at the current delta value _m Is used for the value of (a) and (b),

4: calculate all μ _m And (c) a sum of the two,

5：whileθ<1 do

6: let δ=δ - ε, ε >0

7: repeating the steps 3 and 4

8：end while

9: an optimal value of the problem P2 is obtained,

wherein, as can be seen from (33),mu is _m And mu is the minimum value of (2) _m As a decreasing function of delta. Thus, to obtain an optimal RMS system scheduling policy: first order- >And will be the greatest delta _m The value is delta (in this case, mu _m All take the minimum value +.>The device may meet its minimum transmission requirements); then gradually decreasing the delta value to mu _m Gradually adjusting and increasing the value; finally guarantee->On the premise of (1) iteratively finding the optimal +.>Obtaining an optimal access policy for an RMS system>

In summary, in the case of the coexistence of NCS and RMS, the offline stationary random access policy is shown in algorithm 2.

Algorithm 2: offline stationary random access algorithm:

input: channel information (channel gain distribution)Sub-channel bandwidth B, number of channels W), NCS system information (sensor sampling period T _k Sensor emission frequency P _s,k Controller transmit power P _c,k Status information data quantity L _s,k Control information data volume L _c,k Stability requirement->η _k ) Each RMS system information (device transmit power P _m Minimum transmission requirement->)。

And (3) outputting: NCS system access policy, RMS system access policy.

The NCS system access strategy comprises the following steps:

1: based on the channel information and NCS system information, an NCS sensor access policy is calculated (24).

2: NCS controller access policy: after receiving the transition information received by the NCS sensor, the base station immediately accesses the network to send control information to the executor until the information is sent successfully or the maximum transmission times are reached.

The RMS system access strategy comprises the following steps:

1: obtaining current available communication resources according to NCS system access strategy

2: obtaining optimal access probability of each RMS device according to algorithm 1

3: determining the currently accessed RMS equipment according to the network resource condition and the access probability of the RMS equipment

It should be noted that, in any time slot, the network determines the optimal access strategy of the RMS system according to the number of channelsRandomly selecting RMS device access to ensure long-term average access frequency of any RMS device to meet +.>

Further, for online scheme analysis in online policies:

taking the kth NCS system as an example without loss of generality. In the on-line state, the NCS system can acquire AoI the information flow at the actuator in real time. Therefore, to minimize NCS system resource occupancy while meeting NCS system stability requirements, the access slots of NCS system sensorsThe following should be satisfied: 1) Time slot->Time slots for sensor sampling; 2) In time slot->The information flow AoI at the NCS system executor is satisfied (34).

(34) The representation is: if the NCS sensor still does not access the network to transmit data in the current sampling slot, the system stability requirement cannot be satisfied. Wherein F can be calculated from (17).

Next, solve the problem P3 by using the related method of Lyapunov optimization, design an online RMS system access policy, and maximize the long-term experience quality of the system under the condition of guaranteeing the minimum transmission requirement of the RMS system.

Wherein W is _n The number of wireless channels available to the RMS system in slot n. In the case of determining the NCS system access policy, the system can acquire W at the beginning of time slot n _n Is a value of (2).

The optimization objective of P3 is a separable utility function. Simultaneously according to formulas (8) - (10), each MOS _m Are all about R _m Is a continuous and non-decreasing concave function. Therefore, lyapunov is utilized to optimize solving problem P3 by introducing auxiliary variables and constructing a virtual queue.

MOS is defined as the optimal solution of the above problem under the following additional constraint:

/>

wherein, the liquid crystal display device comprises a liquid crystal display device,is a specific maximum value (let->). In this way, the solution of P3 conforms to the utility maximization problem architecture of the time-averaged function. Since there is no actual queue in the model of P3, virtual queue Z is introduced _m (n) and G _m (n) its queue updates are as follows:

G _m (n+1)＝max{G _m (n)+ρ _m,n -μ _m,n r _m,n ,0}, (38)

wherein ρ is _m,n R is an auxiliary variable _m,n ＝Blog ₂ (1+P _m ·h _m (n)). The solution of P3 can be obtained by solving the following auxiliary variable update problem and access control problem on a slot-by-slot basis.

At each time slot n, each RMS device G according to the current time slot _m (n) updating the auxiliary variable ρ by solving the auxiliary variable update problem described below _m,n 。

Wherein V is a positive real number,

similarly, in each time slot n, the system depends on the current system state r _m,n Virtual queue value G _m (n) and Z _m (n) obtaining the current time slot RMS system access strategy by solving the following access control problem.

Wherein the application can define the weight of RMS device m at time slot n as ω _m,n ＝r _m,n G _m (n)+r _m,n Z _m (n). To obtain the optimal solution of the problem (40), a maximum weight access strategy is adopted, namely: at each time slot n, the system selects a weight ω _m,n The largest device accesses the system first until the current time slot has no idle channel.

In addition, for the maximum weight access policy, as shown in algorithm 3:

input: channel information (subchannel bandwidth B, channel number W), NCS system information (sensor sampling period T _k Sensor emission frequency P _s,k Controller transmit power P _c,k Status information data quantity L _s,k Control information data volume L _c,k Stability requirementsη _k ) Each RMS system information (device transmit power P _m Minimum transmission requirement->)。

And (3) outputting: NCS system access strategy and RMS system access strategy

Initializing: a is that _s,k (1)，A _c,k (1)，A _a,k (1)，Z _m (0)，G _m (0)，n＝1。

1：repeat；

2: for all NCS systems at the sampling moment, calculating the sensor access strategy according to the (34);

3: for the controller with state information in the buffer, judging whether the corresponding control information of the last time slot is successfully transmitted or not: if successful, discarding the state information; if not, judging whether the maximum transmission times H are reached, if so, discarding the state information, and if not, continuing to transmit corresponding control information by the access network;

4: computing System current remaining channel resources W _n ；

5: updating virtual queue G _m (n) and Z _m (n) and calculating the RMS device m weight ω _m,n ；

6: access strategy and residual channel resource W according to maximum weight _n Obtaining an RMS system access strategy;

7: from the problem (39), the auxiliary variable ρ is calculated _m,n ；

8：n←n+1；

9：until n＝N。

acquiring an adoption period of an industrial information stream acquired by a sensor in the NCS system, and calculating a first AOI dynamic change value corresponding to the sensor based on the sampling period and the industrial information stream which is latest received by the sensor;

In one mode, the application aims to avoid that the industrial control system occupies a large amount of network resources for pursuing control stability and seriously affects other service performances. Starting from this problem, an improvement is made in the access strategy of the industrial internet system which controls the application system and monitors the application system and stays.

Specifically, firstly, based on the information flow transmission characteristics of the NCS system, aoI is introduced to measure the timeliness of the information flow, and AoI violation probability and the NCS system stability requirement are linked to provide the NCS system stability constraint.

And then, combining QoE related research, measuring the quality of experience of the RMS equipment by using the MOS value, and establishing the problem of maximizing the long-term quality of experience of the RMS system under the constraint of NCS stability.

Finally, aiming at the characteristics of the non-perfect channel state and the perfect channel state, respectively providing an offline random access strategy and an online maximum weight access strategy, and optimizing the problems.

Through the optimization of the two access strategies, the quality of experience of the monitoring application is obviously improved. Meanwhile, the calculation complexity of the optimization algorithm of the two strategies is relatively low.

Optionally, in another embodiment of the present application, as shown in fig. 3, the present application further provides an apparatus for accessing a network by using the system. Comprising the following steps:

a first allocation module 201 configured to allocate a first part of network resources among all network resources for the NCS system, the first part of network resources being minimum network resources required on the premise that stability of the NCS system can be satisfied;

a second allocation module 202 configured to allocate a second part of network resources from all network resources of the RMS system, where the second part of network resources are network resources required for maximizing user experience quality on the premise that the minimum data transmission of the RMS system can be satisfied;

an access module 203 configured to access the NCS system and the RMS system into the industrial internet system based on channel state information.

In another embodiment of the present application, the first allocation module 201 is configured to:

In another embodiment of the present application, the second distribution module 202 is configured to:

In another embodiment of the application, the access module 203 is configured to:

Fig. 4 is a block diagram of a logic structure of an electronic device, according to an example embodiment. For example, the electronic device 300 may be an electronic device.

In an exemplary embodiment, there is also provided a non-transitory computer readable storage medium including instructions, such as a memory including instructions, executable by an electronic device processor to perform a method of system access network as described above, the method comprising: allocating a first part of network resources in all network resources for the NCS system, wherein the first part of network resources are minimum network resources required on the premise of meeting the stability of the NCS system; allocating a second part of network resources in all network resources for the RMS system, wherein the second part of network resources are network resources required for maximizing user experience quality on the premise of meeting the minimum data transmission of the RMS system; based on channel state information, the NCS system and the RMS system are accessed into the industrial Internet system.

Optionally, the above instructions may also be executed by a processor of the electronic device to perform the other steps involved in the above-described exemplary embodiments. For example, the non-transitory computer readable storage medium may be ROM, random Access Memory (RAM), CD-ROM, magnetic tape, floppy disk, optical data storage device, etc.

In an exemplary embodiment, there is also provided an application/computer program product comprising one or more instructions executable by a processor of an electronic device to perform the above-described method of system access to a network, the method comprising: allocating a first part of network resources in all network resources for the NCS system, wherein the first part of network resources are minimum network resources required on the premise of meeting the stability of the NCS system; allocating a second part of network resources in all network resources for the RMS system, wherein the second part of network resources are network resources required for maximizing user experience quality on the premise of meeting the minimum data transmission of the RMS system; based on channel state information, the NCS system and the RMS system are accessed into the industrial Internet system.

Optionally, the above instructions may also be executed by a processor of the electronic device to perform the other steps involved in the above-described exemplary embodiments.

Fig. 4 is an example diagram of an electronic device 300. It will be appreciated by those skilled in the art that the schematic diagram 4 is merely an example of the electronic device 300 and is not meant to be limiting of the electronic device 300, and may include more or fewer components than shown, or may combine certain components, or different components, e.g., the electronic device 300 may also include input-output devices, network access devices, buses, etc.

The processor 302 may be a central processing unit (Central Processing Unit, CPU), but may also be other general purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor 302 may be any conventional processor or the like, the processor 302 being a control center of the electronic device 300, with various interfaces and lines connecting the various parts of the overall electronic device 300.

The memory 301 may be used to store computer readable instructions 303 and the processor 302 implements the various functions of the electronic device 300 by executing or executing computer readable instructions or modules stored in the memory 301 and invoking data stored in the memory 301. The memory 301 may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program (such as a sound playing function, an image playing function, etc.) required for at least one function, and the like; the storage data area may store data created according to the use of the electronic device 300, and the like. In addition, the Memory 301 may include a hard disk, a Memory, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash Card (Flash Card), at least one magnetic disk storage device, a Flash Memory device, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), or other nonvolatile/volatile storage device.

The modules integrated with the electronic device 300 may be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product. Based on such understanding, the present application may implement all or part of the flow of the method of the above-described embodiments, or may be implemented by means of computer readable instructions to instruct related hardware, where the computer readable instructions may be stored in a computer readable storage medium, where the computer readable instructions, when executed by a processor, implement the steps of the method embodiments described above.

Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the application following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice within the art to which the application pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

It is to be understood that the application is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims

1. A method for accessing a network by a system, which is applied to an industrial internet system comprising a real-time monitoring system RMS and a network control system NCS, the method comprising:

2. The method of claim 1, wherein said allocating a first portion of all network resources for the NCS system comprises:

3. The method of claim 2, wherein the step of enabling the timeliness to meet a first minimum condition comprises:

4. The method of claim 3 wherein the third AoI dynamic change value is less than the maximum AoI dynamic change value permitted by the NCS system as determined by the following equation:

5. The method of claim 1, wherein said allocating a second portion of the total network resources for the RMS system comprises:

6. The method of claim 1, wherein said accessing the NCS system and the RMS system into the industrial internet system based on channel state information comprises:

7. An apparatus for network access in an industrial internet system including a real-time monitoring system RMS and a network control system NCS, the apparatus comprising:

8. An electronic device, comprising:

a memory for storing executable instructions; the method comprises the steps of,

a processor for executing the executable instructions with the memory to perform the operations of the method for system access network of any of claims 1-6.

9. A computer readable storage medium storing computer readable instructions which, when executed, perform the operations of the method of accessing a network for a system of any one of claims 1-6.