阅读说明：本技术 一种异质化节点和链路的网络建模方法、通信设备及网络 (Network modeling method, communication equipment and network of heterogeneous nodes and links ) 是由 畅志贤 李钊 祝世通 张远 于 2021-06-11 设计创作，主要内容包括：本发明公开了一种异质化节点和链路的网络建模方法、通信设备及网络。首先,利用二维邻近图对网络进行数学表示,根据网络中节点的类型对节点进行建模,具体包括源节点、目的节点,以及节点内部的各个功能模块；其次,根据无线通信网络中的相同链路具有非对称数据传输能力的特点,对网络通信链路进行建模,具体包括双向链路和单向链路；最后,根据上述异质化节点和链路模型完成通信网络模型的构建；本发明通过建立异质化节点和链路模型,能够针对链路的前向和反向数据传输能力不同、以及节点属性存在差异的网络,构建更加合理的网络模型,从而提高网络性能仿真及分析的准确性。(The invention discloses a network modeling method of heterogeneous nodes and links, communication equipment and a network. Firstly, a two-dimensional adjacent graph is used for carrying out mathematical representation on a network, and nodes are modeled according to the types of the nodes in the network, and specifically comprise a source node, a destination node and each functional module in the nodes; secondly, modeling a network communication link according to the characteristic that the same link in the wireless communication network has asymmetric data transmission capacity, wherein the network communication link specifically comprises a bidirectional link and a unidirectional link; finally, completing the construction of a communication network model according to the heterogeneous node and the link model; by establishing heterogeneous nodes and link models, the invention can construct more reasonable network models aiming at networks with different forward and reverse data transmission capacities of links and different node attributes, thereby improving the accuracy of network performance simulation and analysis.)

1. A network modeling method of heterogeneous nodes and links is characterized by comprising the following steps:

step one, a network is mathematically described by using a two-dimensional neighborhood graph G ═ (V, E), where a set of nodes V ═ V₁,v₂,…,v_NN represents the number of nodes contained in graph G; link set E ═ E_ij}，e_ijRepresenting a node v_iAnd v_jThe link between the two, i, j belongs to {1,2, …, N } and i ≠ j;

establishing a node model consisting of a data receiving module, a data generating module, a data processing module, a data converging module, an output cache and a data sending module according to functions realized by nodes in the wireless communication network, wherein the data receiving module, the data processing module, the output cache and the data sending module are optional modules of the node model, and the data generating module and the data converging module are optional modules of the node model;

step three, the node uses a section of link associated with the node to transmit and receive data in a time division duplex TDD mode, and defines the transmission direction of the link according to the state of the node connected with the link to establish a link model, wherein, the data of the node transmitting the data is transmitted to the adjacent node through the forward link connected with the node, and for the node receiving the data, the data reaches the node from the adjacent node through the reverse link connected with the node;

step four, the node v_iAccording to communication demand, it and adjacent node v_jLink e between_ijDistribution of duplex coefficients alpha_ijWherein α is_ijDenotes v_iTo the link e associated therewith_ijThe forward transmission time of the first link is proportional to the total link data transmission time, and alpha is satisfied_ij∈[0,1]；v_jTo link e_jiMay be expressed as alpha_jiSatisfy α_ij+α_ji1 is ═ 1; finally, according to the node model and the link modelAnd link duplex coefficient alpha_ijAnd constructing a network model.

2. The method according to claim 1, wherein the first step specifically comprises:

the network is mathematically described using a two-dimensional neighborhood graph G ═ (V, E), where the set of nodes V ═ V₁,v₂,…,v_NN represents the number of nodes contained in graph G; link set E ═ E_ij}，e_ijRepresenting a node v_iAnd v_jThe link between i, j ∈ {1,2, …, N } and i ≠ j.

3. The method according to claim 1, wherein the second step specifically comprises:

(1) respectively modeling nodes in a network as a source node to generate data packets, submitting received data packets belonging to the destination node to a high layer of a protocol stack for processing by the destination node, and assuming that one node only can exist in the network in the form of the source node or the destination node;

(2) establishing a source node model consisting of a data receiving module, a data generating module, a data processing module, an output cache and a data sending module;

establishing a target node model consisting of a data receiving module, a data converging module, a data processing module, an output cache and a data sending module;

(3) according to node v_iDegree d of_iDetermining a node v_iWhether data transfer service needs to be provided for the adjacent nodes; if node v_iDegree d of_iV > 1, then v_iV needs to be processed at a higher layer of the protocol stack while generating data as a source node or receiving data as a destination node and submitting data packets belonging to itself to further processing_iForwarding all data packets generated as source nodes or data packets which are received as destination nodes and do not belong to the source nodes according to destination addresses of the packets; if node v_iDegree d of_iWhen 1, then v_iAnd the data transit service is not required to be provided for the adjacent nodes.

4. The method according to claim 1, wherein the fourth step specifically comprises:

(1) in TDD mode, if node v_iUsing link e_ijFor forward and reverse data transmission, alpha is set_ijNot equal to 0 and alpha_ji≠0；

(2) In TDD mode, if node v_iUsing only link e_ijSetting alpha for forward data transmission_ij1 and α_ji0; if node v_jPassing only link e_jiTo v_iTransmit data, v_iDoes not pass through e_ijTo v_jTransmitting data, then setting alpha_ij0 and α_ji＝1。

5. A communication device, characterized in that the communication device performs the method of any of the preceding claims 1 to 4, the communication device comprising:

the data receiving module and the data sending module are respectively used for receiving and forwarding the business data packet in the network;

the data generation module is used for generating service flow/data packet as a service source of the network;

the data processing module is used for processing the data packet generated by the data generating module and the data packet received by the data receiving module from the adjacent node;

the data aggregation module is used for destroying and counting the data packets which are received from the data processing module and belong to the data aggregation module;

the output buffer is used for buffering the output data packet and performing queue management on the data packet entering the buffer.

6. A wireless network applying the network modeling method of heterogeneous nodes and links of any one of claims 1 to 5.

Technical Field

The invention belongs to the field of wireless communication, and discloses a network modeling method of heterogeneous nodes and links, communication equipment and a network.

Background

With the rapid development of communication technology and computer technology, the diversity and complexity of wireless communication network structures are increasingly highlighted, and conventional network research generally considers that all nodes in the network are equal in level and identical in function, and link attributes are completely consistent, that is, a complex heterogeneous communication network is modeled into a homogeneous network formed by nodes and links with the same attributes, and then network performance simulation and analysis are performed. However, in practice most wireless communication networks are composed of heterogeneous nodes and links. On one hand, because the configuration cost and the communication overhead of the full-function nodes are high, the network function is realized through the cooperation among different types of nodes, and the network cost can be reduced; on the other hand, communication links in a network are not all bilaterally symmetric, and non-uniformity of traffic flow in the links or asymmetry of signal propagation quality on the links can cause a link with bilaterally asymmetric data transmission capability.

For network modeling, documents "j.broch, d.a.maltz.d.johnson, y.c.hu.and j.jetcheva, a performance compatibility of multi-hop wireless ad hoc network routing protocols" use a Random way-point (Random way-point) motion model for network modeling, and give a detailed packet-level simulation result, which compares the performance of the multi-hop wireless ad hoc network routing protocols including DSDV, TORA, DSR and AODV. Documents "v.geotha, Sridhar Aithal, h.xiao, w.k.g.seah, a.lo, and k.c.chua, a flexible quality of service model for mobile ad-hoc networks [ C ], IEEE,2000: 445-.

In conclusion, the accurate network model has important significance on the accuracy of theoretical analysis and simulation verification of network performance. The traditional network model generally describes an actual network by a simple directed graph or undirected graph, ignores the difference of nodes and links in the network, and applies data services in the simplified network model, thereby performing theoretical analysis and simulation experiments on the network (topology) performance. Although the construction of the network model is simplified to a certain extent by the assumption of the homogeneous nodes and links, the attributes of different nodes in the actual network and the difference of the bidirectional data transmission capability of the links cannot be accurately described, so that the network performance simulation and analysis performed in the network model constructed under the assumption of the homogeneous nodes and links have distortion, and the authenticity and the availability of the result cannot be ensured.

Disclosure of Invention

In order to solve the limitation of the network model established under the assumption of the traditional homogeneous node and link in network simulation and analysis, the invention provides a network modeling method, a wireless network and equipment of heterogeneous nodes and links.

Further, the network modeling method, the wireless network and the device for the heterogeneous nodes and the links specifically comprise the following steps:

step one, a network is mathematically described by using a two-dimensional neighborhood graph G ═ (V, E), where a set of nodes V ═ V₁,v₂,…,v_NN represents the number of nodes contained in graph G; link set E ═ E_ij}，e_ijRepresenting a node v_iAnd v_jThe link between the two, i, j belongs to {1,2, …, N } and i ≠ j;

establishing a node model consisting of a data receiving module, a data generating module, a data processing module, a data converging module, an output cache and a data sending module according to functions realized by nodes in the wireless communication network, wherein the data receiving module, the data processing module, the output cache and the data sending module are optional modules of the node model, and the data generating module and the data converging module are optional modules of the node model;

step three, the node uses a section of link associated with the node to transmit and receive data in a time division duplex TDD mode, and defines the transmission direction of the link according to the state of the node connected with the link to establish a link model, wherein, the data of the node transmitting the data is transmitted to the adjacent node through the forward link connected with the node, and for the node receiving the data, the data reaches the node from the adjacent node through the reverse link connected with the node;

step four, the node v_iAccording to communication demand, it and adjacent node v_jLink e between_ijDistribution of duplex coefficients alpha_ijWherein α is_ijDenotes v_iTo the link e associated therewith_ijThe forward transmission time of the first link is proportional to the total link data transmission time, and alpha is satisfied_ij∈[0,1]；v_jTo link e_jiMay be expressed as alpha_jiSatisfy α_ij+α_ji1 is ═ 1; finally, according to the node model, the link model and the link duplex coefficient alpha_ijAnd constructing a network model.

Further, the first step comprises:

the network is mathematically described using a two-dimensional neighborhood graph G ═ (V, E), where the set of nodes V ═ V₁,v₂,…,v_NN represents the number of nodes contained in graph G; link set E ═ E_ij}，e_ijRepresenting a node v_iAnd v_jThe link between i, j ∈ {1,2, …, N } and i ≠ j.

Further, the second step comprises:

(1) respectively modeling nodes in the network as a source node (as an information source to generate data packets) and a destination node (as an information sink to submit received data packets belonging to the node to a high layer of a protocol stack for further processing), and assuming that one node can only exist in the network in the form of the source node or the destination node;

(2) establishing a source node model consisting of a data receiving module (called a receiver), a data generating module, a data processing module (called a processor), an output cache and a data transmitting module (called a transmitter); establishing a target node model consisting of a data receiving module (called a receiver), a data aggregation module, a data processing module (called a processor), an output cache and a data sending module (called a sender);

(3) according to node v_iLocation in the network, i.e. node v_iDegree d of_iDetermining a node v_iWhether it is necessary to provide data relay service for its neighbor nodes. If node v_iWithin the network, i.e. satisfy d_iV > 1, then v_iV needs to be processed at a higher layer of the protocol stack while generating data as a source node or receiving data as a destination node and submitting data packets belonging to itself to further processing_iForwarding all data packets generated as source nodes or data packets which are received as destination nodes and do not belong to the source nodes according to destination addresses of the packets; if node v_iAt the edge of the network, i.e. satisfying d_iWhen 1, then v_iAnd the data transit service is not required to be provided for the adjacent nodes.

Further, the third step includes:

(1) the node uses a section of link associated with the node in a Time Division Duplex (TDD) mode to transmit and receive data;

(2) defining the transmission direction of the link according to the state of sending or receiving data of the node connected with the link; wherein, for a node sending data, the data of the node is sent to a neighbor node thereof through a Forward Link (Forward Link) connected with the node; for a node receiving data, the data arrives at the node from its neighbors via a back Link connected to the node, connecting node v_iAnd v_jLink e of_ijIs used for node v in TDD mode_iAnd v_jIn a bidirectional data transmission.

Further, the fourth step includes:

(1) in TDD mode, if node v_iUsing link e_ijFor forward and reverse data transmission, i.e. v_iNot only via link e_ijTo v_jSending data through e_jiReceiving from v_jIs set to alpha_ijNot equal to 0 and alpha_ji≠0；

(2) In TDD mode, if node v_iUsing only link e_ijFor forward data transmission, i.e. v_iVia link e_ijTo v_jTransmit data, v_jDoes not pass through e_jiTo v_iTransmitting data, then setting alpha_ij1 and α_ji0; similarly, if node v_jPassing only link e_jiTo v_iTransmit data, v_iDoes not pass through e_ijTo v_jTransmitting data, then setting alpha_ij0 and α_ji＝1。

Another object of the present invention is to provide an apparatus, which includes a data receiving module (called a receiver) and a data transmitting module (called a transmitter) for respectively receiving and forwarding a service data packet in a network; the data generation module is used for generating service flow/data packet as a service source of the network; the data processing module (called a processor) is used for processing the data packet generated by the data generating module and the data packet received by the data receiving module from the neighbor node; the data aggregation module is used for destroying and counting the data packets which are received from the data processing module (called as a processor) and belong to the data aggregation module; the output buffer is used for buffering the output data packet and performing queue management on the data packet entering the buffer.

Compared with the prior art, the invention has the following advantages:

the invention constructs a more reasonable network model aiming at the network with different forward and reverse data transmission capacities of the link and different node attributes, and particularly improves the accuracy of theoretical analysis and simulation verification of the network by using heterogeneous nodes and link models.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained from the drawings without creative efforts.

Fig. 1 is a schematic diagram of an implementation process of a network modeling method for heterogeneous nodes and links according to an embodiment of the present invention.

Fig. 2 is a schematic network model diagram of a satellite network to which the network modeling method for heterogeneous nodes and links provided by the embodiment of the invention is applied.

Fig. 3 is a flowchart illustrating an implementation of a topology control algorithm verified in the network model based on fig. 2 according to an embodiment of the present invention.

Fig. 4 is a MATLAB simulation diagram of an initial network topology obtained by executing a Minimum Spanning Tree (MST) algorithm based on the topology control algorithm of fig. 3 according to an embodiment of the present invention.

Fig. 5 is a simulation diagram of a change in the length of a node cache queue obtained by performing 5-minute OPNET simulation on a network based on the topology control algorithm of fig. 3 according to an embodiment of the present invention.

Fig. 6 is a MATLAB simulation diagram of a network topology obtained after a first execution of the topology control algorithm based on fig. 3 according to an embodiment of the present invention.

Fig. 7 is a MATLAB simulation diagram of a network topology obtained after the topology control algorithm based on fig. 3 is executed for the second time according to an embodiment of the present invention.

Fig. 8 is a MATLAB simulation diagram of a network topology obtained after a third execution of the topology control algorithm based on fig. 3 according to an embodiment of the present invention.

Fig. 9 is a MATLAB simulation diagram of a network topology obtained after a fourth execution of the topology control algorithm based on fig. 3 according to an embodiment of the present invention.

Fig. 10 is a simulation diagram of a situation that an average end-to-end delay of a packet obtained by performing 5-minute OPNET simulation on a network based on the topology control algorithm of fig. 3 according to an embodiment of the present invention changes with a traffic load.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Aiming at the problems in the prior art, the invention provides a network modeling method, a wireless network and equipment of heterogeneous nodes and links, and the invention is described in detail with reference to the attached drawings.

As shown in fig. 1, the network modeling method and specific implementation procedure of a heterogeneous node and link provided by the present invention include the following:

s101: performing mathematical representation on a network by using a two-dimensional adjacent graph, and modeling nodes according to the types of the nodes in the network, wherein the nodes specifically comprise a source node, a destination node and each functional module in the nodes; establishing a source node model consisting of a data receiving module (called a receiver), a data generating module, a data processing module (called a processor), an output cache and a data transmitting module (called a transmitter); establishing a target node model consisting of a data receiving module (called a receiver), a data aggregation module, a data processing module (called a processor), an output cache and a data sending module (called a sender);

s102: modeling a network communication link according to the characteristic of asymmetric data transmission on the same link in a wireless communication network, wherein the network communication link specifically comprises a bidirectional link and a unidirectional link; defining the transmission direction of the link according to the state of sending or receiving data of the node connected with the link; for a node sending data, the data of the node is sent to other adjacent nodes through a Forward Link (Forward Link) connected with the node; for a node receiving data, the data arrives at the node from a neighboring node via a reverse Link (backed Link) connected to the node.

S103: completing the construction of a communication network model according to the heterogeneous nodes and the link model;

those skilled in the art can also implement the network modeling method based on heterogeneous nodes and links by using other steps, and the network modeling method based on heterogeneous nodes and links provided by the present invention in fig. 1 is only a specific embodiment.

As shown in fig. 2, the network modeling method of the present invention is applied to a satellite network, where the satellite network is composed of 10 satellites and 1 ground station, and the network modeling method of a heterogeneous node and a link provided in the embodiment of the present invention specifically includes the steps of:

step one, a network is mathematically described by using a two-dimensional neighborhood graph G ═ (V, E), where a set of nodes V ═ V₁,v₂,…,v_NN represents the number of nodes contained in graph G; link set E ═ E_ij}，e_ijRepresenting a node v_iAnd v_jThe link between the two, i, j belongs to {1,2, …, N } and i ≠ j;

establishing a node model consisting of a data receiving module (called a receiver), a data generating module, a data processing module (called a processor), a data aggregation module, an output cache and a data sending module (called a sender) according to functions realized by nodes in the wireless communication network, wherein the data receiving module, the data processing module, the output cache and the data sending module are optional modules of the node model, and the data generating module and the data aggregation module are optional modules of the node model;

step three, the node uses a section of link associated with the node to transmit and receive data in a Time Division Duplex (TDD) mode; the transmission direction of a Link is defined according to the state of data transmission or reception of a node to which the Link is connected, wherein for a node transmitting data, the data of the node is transmitted to its neighboring node via a Forward Link (Forward Link) connected to the node, and for a node receiving data, the data arrives at the node from its neighboring node via a reverse Link (Backward Link) connected to the node, i.e., a connecting node v_iAnd v_jLink e of_ijIs used for node v in TDD mode_iAnd v_jBidirectional data transmission between;

step four, the node v_iAccording to communication demand, it and adjacent node v_jLink e between_ijDistribution of duplex coefficients alpha_ijIn which α is_ijDenotes v_iTo the link e associated therewith_ijThe forward transmission time of the first link is proportional to the total link data transmission time, and alpha is satisfied_ij∈[0,1](ii) a Similarly, v_jTo link e_jiMay be expressed as alpha_jiSatisfy α_ij+α_ji1 is ═ 1; finally, according to the node model, the link model and the link duplex coefficient alpha_ijAnd constructing a network model.

As shown in fig. 3, the executing steps of the topology control algorithm verified in the network model based on fig. 2 provided by the embodiment of the present invention include:

dividing a three-dimensional space into different regions by a node, and forming different pointed wide beams aiming at the different regions to search for adjacent nodes so as to complete adjacent node discovery;

each node independently executes a Minimum Spanning Tree (MST) algorithm to generate an initial topological graph;

each node is provided with three threshold values, wherein the first threshold value defines an upper limit value of the node compensation link quantity, and the second threshold value T_HAn upper threshold value and a third threshold value T for specifying node cache occupancy rate_LA lower threshold value of the node cache occupancy rate is specified, and all nodes are provided with the same first threshold value, the same second threshold value and the same third threshold value;

step two, setting a time interval delta t and a node v_iAccording to the time interval, the transport layer calculates the node v regularly_iCache occupancy η at current time t_i(t) and rate of change of node cache occupancy γ_i(t) and mixing η_i(t) and γ_i(t) encapsulation into a cross-layer data unit (CLDU), and then sending the cross-layer data unit to node v_iThe data link layer of (a); node v_iEstablishing a set V of assisted nodes_i ^rAnd a set of booster nodes V_i ^h，Representation collectionThe number of the elements in the (A) is,a set of representations V_i ^hNumber of elements in (1), initialization Representing an empty set;

step three, node v_iV is obtained by information interaction with each adjacent node_iEach neighboring node ofCache occupancy η at time t_j(t); node v_iAccording to the obtained adjacent node v_jEta of_j(t)、Andinformation, find all satisfy η_j(t)＜T_H、And isIs formed into a node v_iCandidate booster node setNode v_iWill be provided withSet of intermediate booster nodes V_i ^hOr in the set V_i ^c,initDeleting the node in (1), and comparing with V_i ^chThe elements in (b) are sorted in ascending order according to the cache occupancy rate, wherein the node v_iThe set of established neighbor nodes is marked as V_i ⁿ＝V-{v_iV denotes a set of nodes in the network,representing a AND node v in an initial topology_iEstablishing a neighbor node set of links, initializingNode v_iAccording toAndjudging the link compensation condition if the link compensation condition is metAnd isExecuting the fourth step if the result satisfiesAnd isExecuting the step five if the requirement is metAnd isExecuting the step six;

step four, the node v_iThe change rate gamma of the cache occupancy rate at the time t_i(t) comparing with 0 if gamma is satisfied_i(t) < 0, then the third step is executed again after waiting for the time interval delta t; if gamma is satisfied_i(t) is greater than or equal to 0, then v_iCalculating the cache occupancy rate eta of the time interval delta t_i(t + Δ t), and eta is judged_iWhether or not (T + Δ T) exceeds a second threshold T_HIf η is satisfied_i(t+Δt)＞T_HExecuting step seven if eta is satisfied_i(t+Δt)≤T_HIf yes, the third step is executed again after waiting for the time interval delta t;

step five, the node v_iThe change rate gamma of the cache occupancy rate at the time t_i(t) comparing with 0 if γ is satisfied_i(t) < 0, node v_iThen the cache occupancy rate eta of the cache at the time t is calculated_i(T) and a third threshold T_LComparing if η is satisfied_i(t)≤T_LThen execute step eight, if η is satisfied_i(t)＞T_LIf yes, the third step is executed again after waiting for the time interval delta t; if gamma is satisfied_i(t) is greater than or equal to 0, then node v_iNumber of elements included in its set of helper nodesAnd a first thresholdComparing if satisfiedThen the third step is executed again after waiting the time interval delta t, if the third step is satisfiedV is then_iCalculating the cache occupancy rate eta of the time interval delta t_i(t + Δ t), and eta is judged_iWhether or not (T + Δ T) exceeds a second threshold T_HIf η is satisfied_i(t+Δt)＞T_HExecuting step seven if eta is satisfied_i(t+Δt)≤T_HIf yes, the third step is executed again after waiting for the time interval delta t;

step six, the node v_iThe change rate gamma of the cache occupancy rate at the time t_i(t) comparing with 0 if gamma is satisfied_i(t) < 0, then the third step is executed again after waiting for the time interval delta t; if gamma is satisfied_i(t) is greater than or equal to 0, then v_iCalculating the cache occupancy rate eta of delta t after the time interval_i(t + Δ t), and eta is judged_iWhether or not (T + Δ T) exceeds a second threshold T_HIf η is satisfied_i(t+Δt)＞T_HThen execute step eight, if η is satisfied_i(t+Δt)≤T_HIf yes, the third step is executed again after waiting for the time interval delta t;

step seven, the node v_iFrom a set of candidate booster nodes V_i ^chThe node v with the minimum cache occupancy rate is selected_m，v_iTo v_mSending a compensation link establishment request, and if the compensation link establishment is successful, the node v_iAnd node v_mA compensation link is established between so that v_iUsing the compensating link for data transmission, node v_iAfter waiting for the time interval delta t, re-executing the step three; if the establishment of the compensation link fails, the node v_iAbandoning and v_mEstablish a compensating link, then node v_iAfter waiting for the time interval delta t, re-executing the step three;

step eight, node v_iJudging the link compensation state of the self, if the link compensation state is metAnd isNode v_iFrom the set of booster nodes V_i ^hTo select the first and node v_iNode v establishing a compensation link_lAnd v is_iRemove it from v_lV compensation link between_iAfter waiting for the time interval delta t, re-executing the step three; if it satisfiesAnd isThen node v_iFrom a collection of aided nodes V_i ^rTo select the first and node v_iNode v establishing a compensation link_kAnd v is_iRemove it from v_kV compensation link between_iAfter waiting for the time interval delta t, re-executing the step three;

the technical effects of the present invention are described in detail below with respect to simulation:

1. simulation conditions are as follows:

simulation object: the invention provides a network modeling method for heterogeneous nodes and links

Simulation parameters: as shown in fig. 4, simulation randomly generates 10 network nodes in a 150km × 150km area, and executes a Minimum Spanning Tree (MST) algorithm in MATLAB to obtain an initial network topology, where a set V of network nodes is ═ V { (MST)₁,v₂,…,v₁₀And the numbers near each node in the figure represent the number of the node. As shown in fig. 4, the distance between nodes is used as the link weight, and the set of links in the initial network topology obtained after performing MST is performedRepresented by solid line segments in the figure. The MATLAB sends node information and link indirect relation (namely network topology) between nodes to the OPNET, the simulation time length of the OPNET is set to be 5 minutes, the time interval delta t is set to be 1 minute, and a node v is selected in simulation₁,v₄,v₅,v₆,v₁₀Randomly generating data packets as a source node, these data packets being transmitted with equal probability to a destination node v₂,v₃,v₇,v₈,v₉The source node is represented by the larger solid point in fig. 4. In the simulations of fig. 4 to 9, the time interval at which the data generation module of the source node generates packets follows an exponential distribution with a parameter of 1/λ ═ 0.04 (i.e., the average time interval of packets is 1/λ ═ 0.04), and accordingly, the packet (packet) generation rate of the source node is λ ═ 25 packets/s, and the service stations of the respective nodes serve the packets (packets) at a rate of 25 packets/sThe traffic rate is 10 packets/second, and the number of service stations is determined by the degree of the node, the type of edge connected by the node, and the attribute of the node, such as node v in FIG. 4₂And v₆The number of service stations is 1 and 3, respectively, except v₂And v₆The number of the service stations of the other nodes is consistent with the degree of the nodes, because the edge source node (v)₄And v₁₀) Will not help its neighbors (v)₂And v₆) Unload load, so node v₂And v₆Can not pass through the edgeAndto v₄And v₁₀The data packet is transmitted. The OPNET collects the length of a buffer queue of a node required by the execution of a topology control algorithm and the change rate of the length of the buffer queue every minute and sends the length of the buffer queue to the MATLAB, wherein the total length of the buffer queue is set to be 1024 groups, the upper threshold of the buffer occupancy is set to be 0.7, and the lower threshold of the buffer occupancy is set to be 0.4. The MATLAB executes a topology control algorithm to judge whether a compensation link needs to be established or removed (the compensation link is a unidirectional link, and data packets in the compensation link flow from a aided node to a secondary node) according to the cache queue length of the node and the change rate information of the cache queue length transmitted by the OPNET, updates the network topology according to the judgment result, then sends the updated network topology to the OPNET, and the OPNET performs simulation in the next delta t according to the new topology. Finally, in order to further evaluate the improvement condition of the network performance by the dynamic compensation-based cross-layer topology control (DLC-CLTC) algorithm operating in the network model built according to the present invention, the generation rate λ of the packet (packet) generation rate of the source node is set to different values, i.e., λ ∈ {10,15,20,25,30,35} packet/s, and the average end-to-end delay performance of the packet is simulated, as shown in fig. 10.

2. Simulation results and analysis:

when N is 10, a network model is built according to a network modeling method of heterogeneous nodes and linksAnd then simulating a compensation process based on a dynamic compensation cross-layer topological control algorithm (DLC-CLTC) in the model by adopting MATLAB and OPNET. FIG. 5 is a graph of output buffer queue length over time for a 0-5 minute portion of nodes, where the thin solid line represents node v₁The length of the output buffer queue, the thin dotted line representing node v₂The thick solid line represents the node v₄The thick dotted line represents v₅Length of output buffer queue, solid line with rectangular icon representing node v₆Output buffer queue length, solid line with circle icon representing node v₁₀The output buffer queue length. Fig. 6 shows the network topology after the DLC-CLTC algorithm is executed for the first time, the cache occupancy of the corresponding partial node is shown in fig. 5, and when t is 1 minute, the node v₄,v₅,v₁₀The cache occupancy rate exceeds the upper threshold value of the cache occupancy rate, and the cache occupancy rate still has a trend of increasing, therefore, the nodes need to respectively establish compensation links, the network topology after the DLC-CLTC algorithm is executed for the first time is shown in FIG. 6, and the compensation links are increased on the basis of the initial network topologyAndwherein the directional dotted line represents an established compensating link, the arrow tail represents a helped node, and the arrow head represents a helped node, because the data packet can only flow from the helped node to the helped node via the compensating link; fig. 7 is a network topology after the DLC-CLTC algorithm is executed for the second time, and the cache occupancy rate of the corresponding partial node is as shown in fig. 5, when t is 2 minutes, since the cache occupancy rate of no node exceeds the upper threshold of the cache occupancy rate, and the compensated node cache occupancy rate is not lower than the lower threshold of the cache occupancy rate, the network topology after the DLC-CLTC algorithm is executed for the second time is not changed; fig. 8 is a network topology after the DLC-CLTC algorithm is executed for the third time, and the cache occupancy rate of the corresponding partial node is as shown in fig. 5, when t is 3 minutesClock, node v₅The cache occupancy is effectively improved, the cache occupancy is lower than the lower threshold of the cache occupancy and has a trend of descending, so that the method for the node v is removed as shown in fig. 8₅Established compensation linkAt the same time due to node v₁In order to enable traffic packets to be sent from node v as quickly as possible₁Is released, a compensation link is established as shown in fig. 8Fig. 9 shows the network topology after the DLC-CLTC algorithm is executed for the fourth time, and the cache occupancy rate of the corresponding partial node is shown in fig. 5, when t is 4 minutes, since the node v₅The cache occupancy rate of (a) exceeds an upper threshold value of the cache occupancy rate, v₅Seeking node v again₃With the help of which a compensation link is established as shown in fig. 9Fig. 10 is a graph of average end-to-end delay of packets as a function of network traffic, where the line segments with square and triangular icons represent network performance resulting from performing MST and performing DLC-CLTC algorithms, respectively.

The technical effects of the present invention will be described in detail with reference to simulations.

In the experiment, MATLAB and OPNET are adopted to simulate a cross-layer topology control algorithm based on dynamic compensation in a network model built according to a network modeling method of heterogeneous nodes and links, the result is shown in FIG. 5, when the occupancy rate of a node cache queue reaches an upper threshold value of cache occupancy rate, the nodes can dynamically build compensation links so as to reduce the cache occupancy rate of overloaded nodes, and thus the overall performance of the network is improved; as shown in fig. 10, the average end-to-end delay of the packet obtained by using the DLC-CLTC algorithm is lower than the average end-to-end delay of the packet obtained by using the MST, that is, the network after performing the DLC-CLTC algorithm to dynamically adjust the topology structure has lower end-to-end average delay performance given the same node packet generation rate.