CN115551047A

CN115551047A - Wireless communication network and communication method thereof

Info

Publication number: CN115551047A
Application number: CN202211074403.1A
Authority: CN
Inventors: 熊军
Original assignee: Xi'an Yufei Electronic Technology Co ltd
Current assignee: Xi'an Yufei Electronic Technology Co ltd
Priority date: 2022-09-03
Filing date: 2022-09-03
Publication date: 2022-12-30

Abstract

The application relates to the field of communication, in particular to a wireless communication network and a communication method thereof, wherein the communication method comprises the following steps: the central node sends central network information to the wireless communication network; the child nodes maintain the network states of the child nodes according to the central network information and a preset network access rule, and send the sub-network information to the wireless communication network, wherein the network states comprise network states; responding to the network state of the child nodes as the on-network state, the central node calculates a time slot allocation scheme, and allocates time slots for the child nodes according to the time slot allocation scheme, so that the child nodes forward and/or receive and transmit central network information and sub-network information at different time slots according to a preset time slot use criterion; the network nodes respectively construct a topology table of the network nodes according to the central network information and the sub-network information; the network node generates a routing table of the network node; the network node forwards and/or receives the central network information and the sub-network information. The method and the device have the effect of enabling the wireless communication network to operate efficiently and stably.

Description

Wireless communication network and communication method thereof

Technical Field

The present application relates to the field of communications, and in particular, to a wireless communication network and a communication method thereof.

Background

The wireless Mesh network, i.e. the wireless Mesh network, belongs to a multi-hop (multi-hop) network, and is developed from an Ad-Hoc (point-to-point) network. In indoor and other semi-closed or fully-closed spaces, some communication product signals are not enough to be connected with a base station, and the Mesh network can draw adjacent communication product signals, so that the Mesh network is one of key technologies for solving the problem of 'last kilometer' of the communication product with insufficient signals. Meanwhile, the Mesh network can be cooperatively communicated with other networks, is a dynamic network architecture which can be continuously expanded, and can ensure that any two devices can keep wireless communication through the Mesh network.

In a wireless Mesh communication network, information usually needs to be relayed for multiple times when reaching a target node, and different information can reach the target node in time only by passing through different channels, but the on-off conditions among network nodes can change at any time, and when the type and the quantity of the information are large, channel congestion or conflict is easily caused. Therefore, how to make a network node that undertakes a sending task quickly select or form a substitute link to avoid service provision interruption when a wireless link fails, and to make a channel smooth, so that information reaches a target node after being transmitted through a relay, thereby ensuring stable and efficient operation of a wireless network becomes a technical problem to be solved by technical personnel in the field.

Disclosure of Invention

In order to solve at least the above problems, the present application provides a communication method for a wireless communication network, which is applied to a wireless communication network with a central node structure formed in a time division multiple access manner, adjusts a network connection state of the wireless communication network at any time according to a communication demand, establishes a communication route in real time, and calculates an appropriate time slot allocation scheme, thereby completing communication in a reliable manner without channel collision.

The application adopts the following technical scheme to realize the purpose:

in a first aspect, the present application provides a communication method of a wireless communication network, applied to a wireless communication network that communicates in a time division multiplexing manner, where a network node of the wireless communication network includes a central node and a plurality of sub-nodes, the central node controls communication in the entire wireless communication network, and the sub-nodes have a forwarding function, and the communication method includes the following steps: the central node sends central network information to the wireless communication network; the child nodes maintain the network states of the child nodes according to the central network information and a preset network access rule, wherein the network states comprise network states; responding to the network state of the sub-nodes being in a network state, the central node calculates a time slot allocation scheme according to a preset time slot allocation criterion, and allocates time slots for the sub-nodes according to the time slot allocation scheme, so that the sub-nodes forward and/or receive and transmit the central network information and the sub-network information at different time slots according to a preset time slot use criterion; the network node respectively constructs a self topology table according to the central network information and the sub-network information; the network node generates a routing table of the network node according to at least the time slot allocation scheme, a topology table of the network node and a preset routing criterion; and the network node forwards and/or receives the central network information and the sub-network information according to the central network information, the routing table of the network node and the time slot using criterion.

By adopting the technical scheme, the sub-nodes can adjust the network state of the sub-nodes in real time under the control of the central network information and the preset network access rule according to the communication requirement, establish the communication route in real time, and ensure that the original wireless link is quickly selected or formed into a substitute link when the original wireless link fails, thereby avoiding the interruption of service supply, further ensuring that the information reaches the target node after being transmitted by the relay, completing the communication in a reliable manner, and simultaneously ensuring that no conflict occurs under the preset network access rule.

Optionally, the method further comprises the following steps: the network node synchronizes the topology table of the network node according to the central network information and the sub-network information; each of the network nodes regenerates its own routing table in response to each of the network nodes' own topology table having been synchronized.

By adopting the technical scheme, the network node can update the topology table and the routing table of the network node in real time, timely acquire the state of the original wireless link and avoid the phenomenon that the service is interrupted for a long time due to the fact that the substitute link cannot be selected or formed in time when the original wireless link fails.

Optionally, the network state further includes a listening state and an application state.

By adopting the technical scheme, the central node can control the network state of the child nodes according to the actual situation, and when the child nodes are not required to access the network, the child nodes can be controlled to be in the monitoring state, so that the energy consumption of the child nodes is effectively saved.

Optionally, the types of the central network information include broadcast information and control information, and the types of the sub-network information include device detection information and sensing information.

By adopting the technical scheme, the central node can control the network state of the child nodes according to the actual situation, and when the child nodes do not need to access the network, the child nodes can be controlled to be in the monitoring state, so that the energy consumption of the child nodes is effectively saved.

Optionally, the access network criteria include: responding to the child node receiving the broadcast information, and the central node refusing the child node to access the network, wherein the child node is in a monitoring state; responding to the child node receiving the broadcast information, allowing the child node to access the network by the central node, and enabling the child node to be in an application state; responding to the network access application of the child node in the application state being allowed, and enabling the child node to be in the network state.

By adopting the technical scheme, each network node maintains the normal operation of the wireless communication network in a state transition or holding mode. Each network node needs to maintain own network state information and performs state transition under certain conditions, so that the central node can effectively maintain the state of the wireless communication network, and the child nodes also adjust the network states of the child nodes according to the connection conditions of the child nodes and the network, thereby ensuring the normal operation of the wireless communication network.

Optionally, the network status further includes a silence status, and the access criteria further includes: responding to the sub-node not receiving the broadcast information within a preset time, and the sub-node is in a silent state.

By adopting the technical scheme, when the child node is not needed to monitor, the child node can be controlled to be in a silent state, and the energy consumption of the child node is further saved.

Optionally, the timeslot allocation criterion includes: allocating a time frame for each network node according to a time division multiplexing criterion, wherein the time frame number of the time frame is matched with the ID number of the network node corresponding to the time frame; the time frame comprises a plurality of time slots, and different time slots are used for forwarding and/or transceiving different types of central network information and sub-network information.

By adopting the technical scheme, the child nodes send data to the central node according to the requirement sent by the central node and the time slot allocation scheme, and meanwhile, the data contains routing information, so that the data can be transmitted to the central node, and meanwhile, the communication channel can be efficiently utilized due to time division multiplexing, so that rapid communication can be realized.

Optionally, the plurality of time slots include a broadcast time slot, a control time slot, a detection time slot, and an induction time slot; the slot usage criteria include: the broadcast time slot is used for sending broadcast information, the control time slot is used for sending or forwarding control information, the detection time slot is used for sending or forwarding equipment detection information, and the induction time slot is used for sending induction information.

By adopting the technical scheme, different information is sent through different time slots, and the information can be ensured to be orderly transmitted among the network nodes.

Optionally, the control timeslot includes at least one remote control forwarding cycle; the slot usage criteria further includes: and executing one-time control information transmission and at least one-time control information forwarding in one remote control forwarding period.

By adopting the technical scheme, the control information can be ensured to reach the child node.

Optionally, the detection time slot includes a detection transmission time slot and a detection forwarding time slot; the slot usage criteria further includes: responding to the network node in the on-network state corresponding to the ID number matched with the time frame number, and detecting and transmitting the time slot transmitting equipment detection information; otherwise, the detection transmitting time slot is used for sending a network access application by a network node which does not enter the wireless communication network; responding to the network node in the on-network state corresponding to the ID number matched with the time frame number, and detecting and forwarding the time slot forwarding equipment detection information; otherwise, the detection forwarding time slot is used for sending a network access application by a network node which does not enter the wireless communication network.

By adopting the technical scheme, the detection time slot can be multiplexed, the channel is saved, and the communication efficiency is improved.

In a second aspect, the present application provides a wireless communication network, where the wireless communication network communicates in a time division multiplexing manner, and a network node inside the wireless communication network includes a central node and a plurality of sub-nodes, the central node controls communication in the whole wireless communication network, the sub-nodes have a forwarding function, and the central node is configured to send central network information to the wireless communication network; the child nodes are configured to maintain own network states according to the central network information and preset network access criteria, wherein the network states comprise on-network states; in response to the network state of the sub-nodes being in a network state, the central node is further configured to calculate a time slot allocation scheme according to a preset time slot allocation criterion, and allocate time slots to the sub-nodes according to the time slot allocation scheme, so that the sub-nodes forward and/or transmit and receive the central network information and the sub-network information at different time slots according to a preset time slot usage criterion; the network nodes are configured to respectively construct a topology table of the network nodes according to the central network information and the sub-network information; the network node is further configured to generate its own routing table according to at least the time slot allocation scheme, its own topology table and a preset routing criterion; the network node is further configured to forward and/or transceive central network information and sub-network information according to the central network information, its own routing table, and time slot usage criteria.

In summary, according to the technical solution of the present application, under the condition that a communication network topology table is known, each network node can adjust its own on-network state in real time under the control of the central node, so that stable operation of the wireless communication network can be ensured to a greater extent; and each network node can generate point-to-point and point-to-multiple routing tables through the routing criteria, so that communication can be completed in an efficient and reliable manner without collision.

In addition, the network node forwards and/or receives and sends information in different time slots according to a preset time slot using criterion, and the time slots are fully utilized to realize the high-efficiency transmission of the information. Meanwhile, the communication method can also transmit different kinds of information according to the topology table and the time slot allocation scheme.

Drawings

Fig. 1 is a flow chart illustrating a communication method of a wireless communication network according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a slot allocation scheme according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a slot structure according to an embodiment of the present application;

FIG. 4 is a flowchart of actions performed by an information sending module state machine according to one embodiment of the present application;

FIG. 5 is a flowchart of actions performed by a protocol data module state machine according to one embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is further described in detail below with reference to fig. 1-5 and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The wireless Mesh network has evolved into an effective solution suitable for various wireless access networks such as a broadband home network, a community network, an enterprise network, a metropolitan area network and the like by virtue of the characteristics of multi-hop interconnection and Mesh topology. The Mesh router forms a self-organizing Network in a multi-hop interconnection mode, and provides higher reliability, wider service coverage range and lower early investment cost for WMN (Wireless Mesh Network) networking. WMNs inherit most of the characteristics of wireless ad hoc networks, but there are some differences. On the one hand, unlike the mobility of wireless Ad-Hoc network nodes, the location of a wireless Mesh router is typically fixed; on the other hand, wireless Mesh routers typically have a fixed power supply as compared to wireless Ad-Hoc networks with limited energy. In addition, WMNs are also different from wireless sensor networks, generally assuming that the traffic patterns between wireless Mesh routers are relatively stable, much like a typical access network or campus network. Thus, WMNs may act as forwarding networks with relatively stable traffic, such as traditional infrastructure networks. When temporarily deploying WMNs to perform short-term tasks, they can generally act as traditional mobile ad hoc networks.

The general architecture of WMN consists of three different types of radio network elements: a gateway router (a router with gateway or bridge function), a Mesh router (access point) and a Mesh client (mobile terminal or other terminal device). The Mesh client is connected to the wireless Mesh router in a wireless connection mode, and the wireless Mesh router forms a relatively stable forwarding network in a multi-hop interconnection mode. In a general network architecture of the WMN, any Mesh router can be used as a data forwarding relay of other Mesh routers, and some Mesh routers have additional capability of an internet gateway. The gateway Mesh router forwards traffic between the WMNs and the internet over a high-speed wired link. The general network architecture of WMN can be seen as consisting of two planes, where the access plane provides network connectivity to the Mesh clients and the forwarding plane forwards relay traffic between the Mesh routers.

However, no matter in the wireless Mesh network or the WMN networking, multiple relays are usually required for information to reach the target node, and how to adjust the state of the network node in real time to form a shorter communication link and configure an appropriate timeslot allocation scheme to transmit the information in order to enable the information to reach the target node through a shorter link and a shorter duration becomes a problem to be solved by those skilled in the art.

Fig. 1 is a flowchart illustrating a communication method of a wireless communication network according to an embodiment of the present disclosure. The following describes an exemplary communication method of a wireless communication network disclosed in an embodiment of the present application with reference to fig. 1. The communication method of the wireless communication network disclosed by the embodiment of the application is applied to the wireless communication network which communicates in a time division multiplexing mode. Wherein the network nodes of the wireless communication network comprise a central node and a plurality of sub-nodes. The central node controls the communication in the whole wireless communication network, and the child nodes can be wireless Mesh routers and have a forwarding function. The above communication method may comprise steps S101-S106. At step S101, the central node first allocates a time slot for itself in order to transmit central network information to child nodes within the wireless communication network. The allocated time slot may be, for example, a time frame. In one embodiment, the time frame may include a plurality of identical and/or different time slots. In various embodiments, the central node may transmit central network information to child nodes within the wireless communication network during one or more time slots of the time frame. The central network information may include both types of broadcast information and control information. In one application scenario, the broadcast information may include information such as a node table, a node status table, a topology table, and a beacon signal. Wherein the physical addresses of all network nodes within the wireless communication network may be included in the node table. For example, every two bytes in the node table correspond to the physical address of a network node, and the invalid node physical address is represented as 0000H. And the node status table is used to record the network status of each network node. It will be appreciated by those skilled in the art that not only the central node may transmit broadcast information, but also the child nodes may transmit broadcast information.

In one embodiment, the network status may include a silent status, a listening status, an application status, and an on-network status. The correspondence can be represented by "00H" for silence state, "01H" for listening state, "02H" for application state, "03H" for on-network state. The silent state refers to a state after the network node initializes or quits the network, the network node in the state does not transmit any signal, and the local timing is also stopped. The interception state means that the network node receives the broadcast information, but the network node cannot apply for network access because the child node is informed by the control information to refuse network access. The network node in the listening state does not transmit any signal, but the local time is synchronized with the source node (broadcast information source) that sent the broadcast information and keeps counting. And the network node enters an application state after receiving the broadcast information.

In practical applications, the network states may further include a central node state (04H), and the wireless communication network of the present application has only one central node, and the central node first sets itself as the central node state, then always maintains the central node state in the whole communication process, and broadcasts the broadcast information and the control information in a fixed time slot. Specifically, the central node first adds its first physical address to a byte table in its broadcast information, then changes its state to "03H" in a node state table, that is, in a network state, changes a link state from the central node to the central node in a topology table to "1" link, and then broadcasts the broadcast information through a suitable time slot (e.g., the first time slot of a time frame allocated to itself).

In order to store the network states of the network nodes, the node state table allocates 2 bits to the network state of each network node. The network states of the network nodes in the node state table are in one-to-one correspondence with the network nodes in the node table. The topological table represents link states between network nodes in the wireless communication network, the link states include link and disconnection, and can be represented by '1' for link and '0' for disconnection. It will be understood by those skilled in the art that the beacon signal is a synchronization beacon signal in the prior art, which is used to keep the transmitting end and the receiving end of the information synchronized. In some embodiments, the aforementioned broadcast information may also include a time frame number, a time slot number, an ID number, etc. of the network node. After receiving the broadcast information sent by the adjacent network node, the network node updates the information such as the topology table and the node table of the network node.

At step S102, the child node maintains its own network status according to the central network information and the preset access criteria, and transmits sub-network information to the wireless communication network. In one embodiment, the sub-network information may include device detection information and sensing information. The device detection information includes operation information of each sub-node device, and the sensing information may include information such as sound, image, video, temperature, humidity, and the like collected by the sub-node device. The preset access network criteria may include the following: on one hand, when the child node does not receive the broadcast information within a preset time (for example, 3 epochs, where 1 epoch includes N time frames, and N is the number of network nodes in the wireless communication network), the child node is in a silent state; if the child node in the silent state receives the broadcast information and simultaneously receives the information sent by the central node to reject the network access of the child node, for example, the control information sent by the network access protocol to reject the network access of the child node is sent to the child node, the state of the child node may transition to the listening state; while a child node in the listening state may return to the silent state if the broadcast information is not received within a certain time (e.g., 3 epochs). On the other hand, the child node in the silent state receives the broadcast information, and does not receive the information which is sent by the central node and refuses the network access of the child node at the same time, namely the central node allows the network access of the child node, so that the network state of the child node can jump to the application state; meanwhile, after the enabling of the child node in the listening state, which is refused to access the network by the central node, is released, that is, the central node allows the child node to access the network, the state of the child node can also jump to be in the application state. Similarly, if the child node in the application state does not receive the broadcast information within a certain time (e.g., 3 epochs), the child node may also return to the silence state. It is noted that both the central node and the child nodes may be in a silent state.

The following is an exemplary description of the process of entering the foregoing wireless communication network by the child node. And the child nodes in the application state firstly monitor the broadcast information broadcast by the central node and then send network access applications to the central node. Specifically, after monitoring broadcast information broadcast by the central node for the first time, the child node in the application state parses the broadcast information, determines that a state corresponding to a first physical address of the central node in the node state table is an on-network state, and determines that a link state from the central node to the central node in the topology table is a link, and sends a network access application to the central node through a suitable time slot (for example, the 3 rd or 4 th or 5 th time slot of a time frame of the child node), where the network access application at least includes a second physical address of the child node. And after receiving the network access application sent by the child node, the central node allocates an ID number to the child node according to the network access application, updates the broadcast information and broadcasts the broadcast information. Specifically, the central node first determines whether the second physical address in the network access application exists in a network node table, an application node table, or a rejection node table (where the network node table stores information of a network node in a network state, the application node table stores information of a network node in an application state, and the rejection node table stores information of a network node rejected by the central node for network access), and if not, determines whether a spare ID node exists in the network node table; and when the spare ID nodes exist in the network node table, allocating the ID numbers of the spare ID nodes to the child nodes corresponding to the second physical address, and adding the second physical address to the spare ID nodes, wherein the number of the allocated nodes in the network node table is preset.

After the ID numbers are allocated to the child nodes, the central node updates the broadcast information, that is, adds the second physical address to the node table, changes the byte corresponding to the second physical address in the node state table to "01", that is, passes the authentication state, and synchronously changes the link state between the central node and the child node corresponding to the second physical address in the topology table to "1", that is, the link state. The updated broadcast information is then broadcast over the appropriate time slot (e.g., the first time slot of the time frame allocated for itself). And the child node determines whether to access the network according to the updated broadcast information, and after monitoring the updated broadcast information, the child node judges whether a node table in the broadcast information contains a second physical address of the child node, whether a corresponding state in a node state table is an authenticated state, and whether the node table and the central node are in a link state. If the judgment results are yes, the child node can be determined to complete network access. The child node acquires the ID number of the child node from the broadcast information, stores the ID number, and updates the network dimension information of the child node according to the broadcast information.

If the child node in the network state does not receive the broadcast information within a certain time (for example, 3 epochs), or the node table of the broadcast information monitored by the child node does not contain the second physical address of the child node itself, or the child node cannot establish a route with the central node; or the child node receives the information which is sent by the central node and refuses the child node to access the network. The child node in the on-net state transitions to the silent state.

It should be noted that the reason why the device detection information needs to be sent through the fixed time frame is that: the information sent by all the child nodes is sent to the central node, if a plurality of child nodes are sent to the central node or a low-hop node (compared with the child nodes themselves, the network nodes which need fewer relay nodes for communication with the central node) at the same time, node conflict exists, and therefore each network node needs to send equipment detection information in a time slot of a fixed time frame.

At step S103, when the network state of the child node is the on-network state, the central node calculates a time slot allocation scheme according to a preset time slot allocation criterion, and allocates time slots to the child nodes of the on-network according to the time slot allocation scheme, so that the child nodes forward and/or transmit and receive the central network information and the sub-network information at different time slots according to the preset time slot usage criterion. The time slot allocation criterion is as follows: and according to the time division multiplexing criterion, allocating a time frame for each network node, wherein the time frame number of the time frame of each network node is matched with the local ID number of the network node. One time frame includes a plurality of time slots, and different time slots are used for forwarding and/or transceiving different types of central network information and sub-network information. The structure and duration of the time frame of each network node are the same.

Fig. 2 is a schematic diagram of a time slot allocation scheme according to an embodiment of the present application. A time slot allocation scheme disclosed in the embodiment of the present application is exemplarily described below with reference to fig. 2. In one embodiment, the slot allocation scheme is: each time frame includes at least one broadcast slot, one control slot, one detection slot, and one sense slot. The slot usage criteria include: the broadcast time slot is used for sending broadcast information, the control time slot is used for sending or forwarding the control information, the detection time slot is used for sending or forwarding equipment detection information, and the induction time slot is used for sending induction information. Wherein the length and structure of the time frame of the central node may coincide with the length and structure of the time frame of the child node.

The network node in the application state randomly sends the selected idle detection time slot to the network access application, and the local time of the network node is synchronous with the broadcast information source and keeps counting; the network node enters the on-network state after being informed of network access by the central node. The network node in the network state can transmit broadcast information and equipment detection information in the corresponding time slot, and transmit or forward control information, equipment detection information and induction information according to the routing table and system image requirements.

Taking a wireless communication network including a central node and 12 sub-nodes as an example, as shown in fig. 2, the wireless communication network is composed of a ground station (central node) and airborne equipment (sub-nodes), a plurality of airborne equipment and the ground station can be networked, and the wireless communication network supports three hop levels at most. The neighbor nodes of the central node comprise a one-hop neighbor node and a two-hop neighbor node, the one-hop neighbor node can be used as a destination node, and the one-hop neighbor node can also be used as a relay node which takes the two-hop neighbor node as the destination node. The ground station is used as a main control station, the one-hop neighbor nodes can form a one-hop network, and the two-hop neighbor nodes can form a two-hop network. The one-hop network can be composed of a plurality of unmanned/manned data chains, the two-hop network can be composed of a plurality of individual soldiers, and communication links are established between the one-hop network nodes and the main control equipment. Similarly, a three-hop network may be composed of several small devices, and a communication link is established with a ground device (master control station) through a two-hop neighbor node and a one-hop neighbor node, so that the total network supports a minimum of 13 nodes.

The ground station (master control station) consists of a control platform, a terminal and an antenna, and the node equipment consists of an airborne terminal and an antenna. The wireless communication network is designed for the requirement of information exchange of multi-equipment tactical operation units, supports various functions of communication, navigation and identification, and meets the requirement of real-time exchange of reconnaissance data, electronic war data, task execution, weapon distribution and control and the like. The one-hop neighbor nodes (network nodes which can communicate with the central node without relay nodes) are airplanes, unmanned aerial vehicles, armored vehicles and the like, and the two-hop neighbor nodes (network nodes which can communicate with the central node only with one relay node) can be single soldiers. The wireless communication network adopts a TDMA access mode to form a wireless communication network with a central node structure, and the ground station and the airborne equipment transmit information in turn according to the allocated time slots. Meanwhile, by distributing independent frequency hopping patterns, a multi-network structure can be formed to accommodate more members.

Fig. 3 is a schematic structural diagram of a timeslot according to an embodiment of the present application. The structure of a time slot disclosed in the embodiment of the present application is exemplarily described below with reference to fig. 3. As shown in fig. 3, the time slot allocation scheme of the wireless communication network is as follows: a 1 epoch contains 13 (matching the number of nodes) time frames. Each time frame comprises 6 time slots, wherein the time slots 1-5 are short time slots, the maximum transmission of 512bit information of each time slot is realized, the time slot 6 is a long time slot, the maximum transmission of 6144bit information of each time slot is realized, and the structures of the short time slot and the long time slot are shown in figure 3, wherein the long time slot can be used for transmitting induction information (image and video information). Specifically, where a broadcast slot (slot 1) is used for transmitting broadcast information, each network node transmits broadcast information in the broadcast slot, and neighboring network nodes will receive broadcast information transmitted by the other side, the broadcast slot may be used for exchanging broadcast information between neighboring network nodes. The message format of the broadcast information is shown in table 1, and it should be noted that the message format shown in table 1 is only a part of the control information.

Table 1 control information message format because the most critical index of the control information is that the central node can control the child nodes to reach all the child nodes as soon as possible, the situation that multiple child nodes transmit and forward simultaneously can be realized in the control time slot. In one embodiment, the control slot (slot 2) may include at least one remote control forwarding period (transmission of control information and forwarding of control information may be performed once within one remote control forwarding period). Also taking a wireless communication network including one central node and 12 sub-nodes as an example, as shown in fig. 3, the control time slot of every 4 time frames is a remote control forwarding period, so that each time element can forward control information of 3 short time slots. The central node sends control information in fixed time frames (e.g., time frame 2, time frame 6, time frame 10) and the child nodes merely forward the control information. The central node selects which child's time frame (e.g., time frame 3, time frame 4, time frame 5, time frame 7, time frame 8, time frame 9, time frame 11, time frame 12, time frame 13) to forward the control information and sends to the child nodes via broadcast messages. One of the control messages may have 4 transmission opportunities, 1 transmission state and 3 forwarding states.

In one embodiment, the control information may include information for controlling the child nodes. For example, the message format of the control information may be as shown in table 2.

Table 2 control information message format

The broadcast routing table of 4 bits of each node stores relative frame numbers. For example, where byte numbers 9-24 store content that may be:

D(9)＝[broadcast_router(1)broadcast_router(2)]；

D(10)＝[broadcast_router(3)broadcast_router(4)]；

…

D(24)＝[broadcast_router(31)broadcast_router(32)]。

the detection slots include a detection transmission slot (slot 3) and a detection forwarding slot (slot 4 and slot 5). Each node will detect the transmission time slot transmitting device detection information when the time frame number matches with the local ID number (i.e. when the local ID number matching with the time frame number corresponds to the network node in the on-network state). And when the local ID number does not have a corresponding network node in the network state, reserving the time slot for the network node which is not accessed to the network for sending the network access application information. When the ID number matched with the frame number corresponds to the network node in the network state, detecting the detection information of the forwarding time slot forwarding equipment; and otherwise, the forwarding time slot is used for sending a network access application by the network node which does not enter the wireless communication network. Because the equipment detection information transmitted by the detection transmission time slot contains the routing information, other network nodes serve as relay nodes to forward the equipment detection information according to the routing information, so that the equipment detection information can be forwarded to the central node.

The ID number of the relay node is obtained by jointly analyzing the topology table and the topology state table of the child node that sends the device detection information. Wherein the topology state table may for example describe the topology of the above-mentioned wireless communication network and the state of the communication links. For example, the topology state information may include network nodes in a network state, network nodes that contain communication links with a failure state, and communication links previously registered in the network to connect a network node to neighboring network nodes. Different from the control information, the device detection information is selected to be sent in the fixed time frame, because the information of all the child nodes is sent to the central node, if a plurality of child nodes are sent to the central node or the node with relatively low hop simultaneously (the hop count closer to the central node is lower, so that the child nodes can be classified into the node with relatively low hop and the node with relatively high hop), the node conflict can exist, and the device detection information sent by each child node is sent by the time slot of the fixed time frame. The message format of the device detection information may be as shown in table 3.

Table 3 device check information message format

It will be appreciated by those skilled in the art that in order to adapt to a network environment requiring multiple relays, a suitable network protocol is required to ensure stable operation of the wireless network. For example, the control information may be routed through an OLSR (Optimized Link state routing) protocol. OLSR routing is an optimized link state protocol that is optimized for mobile ad hoc networks based on pure link state routing shortest path first. The routing method is essentially an empirical routing mode, so that the routing method has the advantage of small path finding time delay. The optimization of the pure link state algorithm adopts a multipoint relay mechanism, thereby reducing the flooding range of the control packet. The network node selects part of the adjacent nodes as the multipoint relay nodes thereof, and only the relay nodes forward the information of the network node. And when other adjacent nodes receive the control packet sent by the network node, only processing is carried out and forwarding is not carried out. This significantly reduces the number of control packets broadcast in the network. The network node that has reduced the control packets does not publish link information that is connected to all its neighbors, but only a subset of its links to some of its neighbors, which are its multipoint relay nodes, i.e. the network node only publishes links to itself. Meanwhile, the network topology is maintained through periodic information exchange with the central node. The protocol requires that each network node stores its route to all reachable destination nodes in the network, and is therefore suitable for networks with large network size and densely distributed nodes.

The device detection information may be routed through a DSDV (sequence distance vector) protocol, and a relay node ID number in the device detection information is obtained by performing joint analysis on a topology table and a topology state table by a child node that transmits the device detection information. Wherein DSDV is an improved protocol architecture based on destination sequence number distance vector protocol. The routing protocol is obtained by improving a distributed routing algorithm of a classical simple shortest path, and is a table-driven routing protocol. As the name suggests, the table-driven routing protocol relies on a network routing information table maintained in real time by node interaction information, and is a proactive routing protocol. The DSDV protocol improves upon the bellman-ford routing mechanism mainly by avoiding the formation of routing loops in the routing table. Each network node maintains a routing table of next-hop and distance estimates to known nodes in the network in the protocol. Each routing node is a typical distance vector algorithm because it only records the number of hops to the destination node and the next hop information (three hop information ID number) leading to the destination node. A sequence number generated by a destination node is attached to the distance vector routing table, and the node only uses the routing information with the latest sequence number to update the routing table, thereby avoiding the generation of routing loops. Therefore, the advantages of various network protocols can be obtained by adopting various network protocols for communication.

In addition, the DSDV protocol can also solve the problem of route jitter caused by network transmission delay. Two processes, namely route discovery and route maintenance, are mainly involved. In the route discovery process, each network node periodically broadcasts its current routing table including the distance corresponding to each destination node and the known maximum sequence number, etc. The broadcast information also contains the sender's own serial number, which is automatically incremented each time it is broadcast. Each network node receiving the broadcast message compares the serial number of each destination node in the message with the corresponding item in the routing table of the network node, if the serial number in the message is higher, the routing table of the network node is updated, the sender is designated as the next hop, and the distance is increased by one hop. If the sequence numbers are equal but the distances are smaller, the receiving node also updates its routing table. In the route maintenance process, when a network node discovers a link failure, it sets the distance of all destination routes passing through the link to infinity and adds its sequence number. Because the sequence number is updated, the message can be spread to the whole network, thereby avoiding loops, accelerating the speed of message communication and enhancing the real-time property of the mobile ad hoc network.

In one embodiment, the sensing time slot is used for sending sensing information (such as video/photo data) collected by the child node to the central node. According to the acquisition requirement and the time slot allocation scheme sent by the central node, the child nodes send induction information to the central node, and the induction information comprises routing information so as to ensure that the induction information can be forwarded to the central node. The message format of the sensing information can be as shown in table 4.

Table 4 inductive information message format

It will be readily understood by those skilled in the art that the central node specifies in the broadcast message the ID number of the child node that sent the sensing information, and that the specified child node sends the sensing information at the specified time slot.

In order to meet the environment requiring multiple relays and the communication requirement under the condition that the on-off state between network nodes changes at any time, the network node sending the control information, the sensing information, the device detection information or the sensing information needs to acquire the connection topology state of the whole wireless communication network and establish a communication route so as to ensure that the information reaches a target node after being transmitted through the relays. Therefore, at step S104, the network node needs to respectively construct its own topology table according to the received central network information and sub-network information. For example, the network nodes in the on-network state are confirmed through broadcast information, the operation state of each network node is known through equipment detection information, and then a topology table between the network node and other network nodes which normally operate is established. Since the network state of the network node changes in real time, the network node also needs to synchronize its own topology table according to the central network information and the sub-network information.

After each network node completes the construction of the topology table, in step S105, the network node generates its own routing table at least according to the timeslot allocation scheme, its own topology table, and a preset routing criterion (which may be an existing routing criterion, and is not described herein). It is easily understood that when each network node completes its own topology table synchronization, each of the network nodes regenerates its own routing table.

Finally, at step S106, the network node forwards and/or receives the central network information and the sub-network information according to the central network information, its own routing table, and the preset time slot using criteria. For example, the central node and the child nodes both send broadcast information in a first time slot, the central node selects a second time slot of a fixed time frame to send control information, and the child nodes forward the control information in the second time slot; the child nodes detect information to the central node or the forwarding and sending device, and the child nodes send induction information to the central node.

In order to facilitate understanding of the transmission flow of the control information, the device detection information, and the sensing information, the following description is made with reference to an example: taking the communication flow among the network nodes 1, 2 and 5 as an example, after the network nodes 1, 2 and 3 complete network access, the network nodes 1, 2 and 3 are all in an on-network state, where the network node 1 is a central node, and a state machine of the central node (the state machine can perform state transition according to a control signal in a preset state, and is a control center that coordinates related signal actions and completes specific operations) determines that if the control information is in a control information transmission time frame/time slot (for example, time frame 2, time frame 6 and time frame 10), the control information is transmitted, that is, the control information is transmitted to a one-hop neighboring node (for example, network node 2) in time slot 2 of time frame 2, time frame 6 and time frame 10. After receiving the control information, the network node 2 parses the control information to perform corresponding actions (e.g., sending device detection information, forwarding the control information, etc.) according to the control information, and if it is determined that the node is a forwarding route (determined according to descriptions in bytes 9-24 of the control information), the network node 2 forwards the control information to a two-hop neighbor node (e.g., network node 5) in time slot 2. Meanwhile, if the state machine of the one-hop neighbor node polls that the state machine needs to send the equipment detection information to the central node, the equipment detection information is sent to the central node in the time slot 3.

After receiving the control information forwarded by the network node 2, the network node 5 also parses the control information to execute corresponding actions according to the control information. For example, if it is determined from the description in bytes 9 to 24 of the control information that the node does not transmit the control information, the control data in the control information is extracted and used by a layer above the physical layer (for example, a radio link control layer or an application layer). The state machine of the network node 5 queries the nodes one by one, and if the state machine queries that the state machine needs to send device detection information to the central node, the network node 5 confirms the next hop node according to the topology table and the topology state table: ID =2, target node: ID =1, information source node: ID =5, and the device detection information is sent to the network node 2 in slot 3 of time frame 5 after the ID information is filled in. The network node 2 receives the device detection information of the network node 5, and after judging that the device detection information needs to be forwarded, fills in the next hop node ID =1, the target node ID =1, and the information source node ID =5. And then waits for an epoch before being forwarded to the central node in either slot 4 or slot 5 of time frame 2. And after receiving the equipment detection information, the central node extracts the equipment detection data.

The central node may also broadcast the broadcast information periodically, for example, transmitting the broadcast information to the one-hop neighbor node in time slot 1 of a time frame (time frame 1) of the central node, wherein the broadcast information contains an instruction for requesting to transmit the sensing information (e.g., image information), and the node ID number for transmitting the sensing information is designated as 5, that is, the sensing information is transmitted by the network node 5. After receiving the broadcast information, the one-hop neighbor node (e.g., network node 2) forwards the broadcast information to network node 5 (two-hop neighbor node) in timeslot 1 of its own time frame (i.e., time frame allocated by the central node, time frame 2). If the state machine of the network node 5 judges that the control information requires the control information to send the sensing information to the central node, the next hop node ID =2, the target node ID =1 and the information source node ID =5 are filled, and the sensing information is sent to the network node 2 in the time slot 6 of the next time frame, and at the same time, the network node 2 receives the sensing information of the network node 5 and then fills the following information: next hop ID =1, destination ID =1, information source ID =5, and then transmitted to the central node at time slot 6 of the next time frame. And the central node performs relevant processing after receiving the induction information. By the method, the control message can be quickly and accurately sent to each network node, and each network node can orderly and quickly send the equipment detection information to the central node.

It should be noted that the network nodes may include an information transmitting module, which is used to transmit information. The information transmitting module can comprise a transmitting state module and a message generating module, the information transmitting module comprises a state machine, and the information transmitting module is started once every time slot and started after the time slot number jumps. Fig. 4 is a flowchart of actions performed by an information sending module state machine according to an embodiment of the present application. A specific decision flow of a state machine of an information transmitting module in the sending flow of the control information, the device detection information, and the sensing information is exemplarily described below with reference to fig. 4, as shown in fig. 4, after the information transmitting module is started, the state of the node is first determined by the transmitting state module, if the node is in an application state and is in a time slot 3, a time slot 4, or a time slot 5, and meanwhile, the random seed satisfies a network access condition, network access application data is generated, and then a network access application is initiated. Since the sending of the device detection information and the sensing information requires the network node to be in the on-network state, it is first necessary to determine whether the node is in the on-network state. And if the node is in the network state, next time slot judgment is carried out, and if the time slot is the time slot 6 and the time slot is a forwarding time slot allocated to the child node, induction data corresponding to the induction information is generated and sent. If the time slot is 3 and the ID number of the node is matched with the relative time frame number, generating equipment detection data corresponding to the equipment detection information and sending the equipment detection data; and if the time slot is the time slot 4 or the time slot 5 and the time slot is a forwarding time slot allocated to the child node, generating device detection data corresponding to the device detection information and forwarding the device detection data.

In addition, the network node is required to be in an on-network state or a central node state due to the transmission of the broadcast information and the control information. So it needs to judge whether the node is in the on-network state. If the node is in the network state or the central node state and the current frame number is matched with the ID number of the network node, then time slot judgment is carried out, if the current frame number is time slot 1, broadcast data corresponding to the broadcast information is generated and sent; and if the time slot is time slot 2, the routing information in the broadcast information contains the ID number of the node, and the ID number of the node is matched with the current time frame number, generating control data corresponding to the control information and sending the control data.

If the node receives a control signal for sending induction information (such as image information) and judges that the node is not in an online state before transmission, caching the induction information; similarly, if the node has received a control signal for sending the broadcast information or serves as a central node to send the broadcast information, but before transmission, the node is judged not to be in the network state and not to be in the central node state, the broadcast information is cached; similarly, if the node has received the control signal for forwarding the control information or serves as a central node to send the control information, but before transmission, the node is judged not to be in the network state and not to be in the central node state, the control information is cached; similarly, if the node has received the control signal for sending or forwarding the device detection information, but before the transmission, the node is judged not to be in the on-network state, the device detection information is cached.

After the information transmitting module generates the enable, the transmitting module waits for the transmitting time (related to the processing delay of the physical layer transmitting module), and outputs the data to the physical layer at the transmitting time to finish the data transmission of the current time slot. After the transmission is completed, the information transmission module may change the local state data according to the information fed back by the message generation module, and the specific operation is as shown in table 5.

Table 5 update operation of information transmitting module to local state

Fig. 5 is a flowchart of actions performed by a protocol data module state machine according to an embodiment of the present application. The following describes exemplary actions performed by the protocol data module state machine disclosed in one embodiment of the present application with reference to fig. 5. It will be readily understood by those skilled in the art that the network node may further include a protocol data module, which runs once per time frame and starts when a local time frame number jumps, and the state machine execution flow of the protocol data module includes steps S201 to S208.

At step S201, when a local time frame number jumps, the state of the protocol data module is mobile; at step S202, the state machine of the protocol data module identifies the network state of the network node, and if the network node is in a silent state, a listening state, or an application state, the process is directly ended; if the network node is a child node and is in an on-network state, step S203 is entered, and it is determined whether the current frame number matches (i.e. matches) the ID number of the network node; if the time frame number is matched with the ID number of the network node, step S204 is carried out, a message corresponding to the equipment detection information is generated through the message generation module, the message is taken as a short data block to be transferred and stored, and meanwhile, the transmitting time of the short data block is corrected; if the time frame number is not matched with the ID number of the network node, step S205 is carried out, whether the current network node sends induction information is judged, if yes, step S206 is carried out, a message corresponding to the induction information is generated through the message generation module, the message is stored as a long data block, and meanwhile, the transmission time of the long data block is corrected; if not, the process ends.

If the network node is a central node and is in an on-network state, step S207 is performed to determine whether the network node is a time slot for sending control information, and if so, step S208 is performed to generate a message corresponding to the control information through the message generation module, and then the process is ended. If not, the process ends. And after the running of the state machine is finished, the protocol data module finishes the updating of the network state of the network node. The protocol data module makes changes to the network state of the network node, for example as shown in table 6.

Table 6 update operation of a protocol data module on a network status of a network node

In summary, the implementation principle of the wireless communication network includes: in a wireless communication network (such as a wireless Mesh backhaul network), a TDMA mode (time division multiplexing) is adopted to divide a channel into time slots so as to use the time slots as a scheduling unit of a MAC layer. Each network node is equipped with a single transceiver and works in a half-duplex mode, namely, the network nodes can only transmit or receive data at the same time and cannot simultaneously transmit and receive the data. Unicast communication is adopted among network nodes, namely, each transmission only comprises one sender and one receiver. A network node cannot receive data transmissions from two links or channels simultaneously.

The network node comprises a central node and sub-nodes, the central node is assumed to be a centralized scheduling server in the wireless communication network and is used for managing the allocation and scheduling of time slots and links, and a special broadcast time slot is used as a common control channel (which does not interfere with a data channel) for information exchange between the scheduling server and all Mesh router nodes (sub-nodes) in the network. The scheduling server periodically collects information of all router nodes (including information of service requirements of all network nodes, channel conditions of all network nodes and the like), calculates a time slot and link allocation and scheduling scheme before the beginning of each scheduling period, and broadcasts the time slot and link allocation and scheduling scheme to all router nodes in the network. Each network node accesses the corresponding channel according to the received scheme. If the scheduling server finds that the channel condition or the service requirement changes, the allocation and scheduling scheme is recalculated.

The method mainly comprises the technologies of network node network access, time slot allocation, topological table synchronization establishment, routing operation and the like. Wherein, the network node accessing network mainly comprises: the network management, ID number distribution, network access/network exit strategy and the like. The time slot allocation mainly comprises the reasonable allocation of time slots to corresponding channels to meet the communication requirements of the system. The topology table establishment and synchronization comprises the following steps: and the synchronization of the topology table of the network nodes in the node table is completed by detecting the receiving state of the broadcast information and reading the information such as the topology table, the topology timeliness and the like. The routing operation mainly comprises: under the condition of topology table synchronization, the network node runs a routing algorithm, searches for the relay node in the network, and completes data transmission in the multi-hop relay environment. The implementation of the above technology needs to be accomplished by exchanging broadcast information in a broadcast time slot through a network node in an on-network state. In one embodiment, the specific process implemented by the above technique is as follows: firstly, network access of network nodes is completed by sending broadcast information, and topology table establishment, updating and synchronization are carried out after the network nodes are accessed; the network node then performs routing table calculations based on the slot allocation scheme and the broadcast information.

Meanwhile, the embodiment of the application also discloses a wireless communication network which communicates in a time division multiplexing mode, wherein the internal network nodes of the wireless communication network comprise a central node and a plurality of sub-nodes, the central node controls the communication in the whole wireless communication network, the sub-nodes have a forwarding function, and the central node is configured to send central network information to the wireless communication network; the child nodes are configured to maintain own network states according to the central network information and preset network access criteria, wherein the network states comprise on-network states; in response to the network state of the sub-nodes being in a network state, the central node is further configured to calculate a time slot allocation scheme according to a preset time slot allocation criterion, and allocate time slots to the sub-nodes according to the time slot allocation scheme, so that the sub-nodes forward and/or transmit and receive the central network information and the sub-network information at different time slots according to a preset time slot usage criterion; the network nodes are configured to respectively construct topology tables of the network nodes according to the central network information and the sub-network information; the network node is further configured to generate its own routing table according to at least the time slot allocation scheme, its own topology table and a preset routing criterion; the network node is further configured to forward and/or transceive central network information and sub-network information according to the central network information, its own routing table, and a preset time slot usage criterion.

The communication is realized through a plurality of network modes, the communication route of point-to-point and point-to-multipoint (broadcasting) can be generated through an algorithm under the condition of a known network structure topological graph, and the communication is completed in an efficient and reliable mode under the condition of no conflict. The present disclosure maintains the normal operation of the wireless communication network in a network node state transition (switching of network state)/maintaining manner. Each network node needs to maintain own network state information, and performs state transition under the condition of meeting a certain condition, so that the central node can effectively maintain the network state, and the child nodes also adjust the state according to the connection condition of the child nodes and the wireless communication network, thereby ensuring the normal operation of the wireless communication network.

The foregoing is a preferred embodiment of the present application and is not intended to limit the scope of the present application in any way, and any features disclosed in this specification (including the abstract and drawings) may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

Claims

1. A communication method of a wireless communication network, applied to a wireless communication network communicating by a time division multiplexing manner, wherein network nodes of the wireless communication network comprise a central node and at least one sub-node, the central node controls communication in the whole wireless communication network, and the sub-node has a forwarding function, the communication method comprising the following steps:

the central node sends central network information to the wireless communication network;

the child nodes maintain the network states of the child nodes according to the central network information and a preset network access rule, wherein the network states comprise network states;

responding to the network state of the sub-nodes being in a network state, the central node calculates a time slot allocation scheme according to a preset time slot allocation criterion, and allocates time slots for the sub-nodes according to the time slot allocation scheme, so that the sub-nodes forward and/or receive and transmit the central network information and the sub-network information at different time slots according to a preset time slot use criterion;

the network node respectively constructs a self topology table according to the central network information and the sub-network information;

the network node generates a routing table of the network node according to the time slot allocation scheme, a topology table of the network node and a preset routing criterion;

and the network nodes forward and/or receive and transmit the central network information and the sub-network information according to the central network information, the routing tables of the network nodes and the time slot using criteria.

2. The communication method of the wireless communication network according to claim 1, further comprising the steps of:

the network node synchronizes the topology table of the network node according to the central network information and the sub-network information;

each of the network nodes regenerates its own routing table in response to each of the network nodes' own topology table having been synchronized.

3. The communication method of the wireless communication network according to claim 1 or 2, wherein the network state further comprises a listening state and an application state.

4. The method of claim 3, wherein the types of the central network information comprise broadcast information and control information, and the types of the sub-network information comprise device detection information and sensing information.

5. The communication method of claim 4, wherein the network entry and exit criteria comprise:

responding to the fact that the child node receives the broadcast information, the central node refuses the child node to access the network, and the child node is in a monitoring state;

responding to the child node receiving the broadcast information, allowing the child node to access the network by the central node, and enabling the child node to be in an application state;

responding to the network access application of the child node in the application state being allowed, wherein the child node is in the network state.

6. The communication method of the wireless communication network according to claim 5, wherein the network status further comprises a silence status, and the access criteria further comprises: responding to the sub-node not receiving the broadcast information within a preset time, and enabling the sub-node to be in a silent state.

7. Communication method of a wireless communication network according to claim 5, wherein said time slot allocation criterion comprises:

allocating a time frame for each network node according to a time division multiplexing criterion, wherein the time frame number of the time frame is matched with the ID number of the network node corresponding to the time frame;

the time frame comprises a plurality of time slots, and different time slots are used for forwarding and/or transceiving different types of central network information and sub-network information.

8. The communication method of the wireless communication network according to claim 7,

the plurality of time slots comprise a broadcast time slot, a control time slot, a detection time slot and an induction time slot;

the slot usage criteria include:

the broadcast time slot is used for sending broadcast information, the control time slot is used for sending or forwarding control information, the detection time slot is used for sending or forwarding equipment detection information, and the induction time slot is used for sending induction information.

9. The communication method of the wireless communication network according to claim 8,

the detection time slot comprises a detection transmitting time slot and a detection forwarding time slot;

the slot usage criteria further includes:

responding to the network node in the on-network state corresponding to the ID number matched with the time frame number, and detecting and transmitting the time slot transmitting equipment detection information; otherwise, the detection transmitting time slot is used for sending a network access application by a network node which does not enter the wireless communication network;

responding to the network node in the on-network state corresponding to the ID number matched with the time frame number, and detecting and forwarding the time slot forwarding equipment detection information; otherwise, the detection forwarding time slot is used for sending a network access application by the network node which does not enter the wireless communication network.

10. A wireless communication network, the wireless communication network communicating via time division multiplexing, the network nodes therein comprising a central node and a plurality of sub-nodes, the central node controlling the communication throughout the wireless communication network, the sub-nodes having forwarding functionality, characterized in that:

the central node is configured to transmit central network information to the wireless communication network;

the child nodes are configured to maintain own network states according to the central network information and preset network access criteria, wherein the network states comprise on-network states;

in response to the network state of the sub-nodes being in a network state, the central node is further configured to calculate a time slot allocation scheme according to a preset time slot allocation criterion, and allocate time slots to the sub-nodes according to the time slot allocation scheme, so that the sub-nodes forward and/or transmit and receive the central network information and the sub-network information at different time slots according to a preset time slot usage criterion;

the network nodes are configured to respectively construct a topology table of the network nodes according to the central network information and the sub-network information;

the network node is further configured to generate its own routing table according to at least the time slot allocation scheme, its own topology table and a preset routing criterion;

the network node is further configured to forward and/or transceive central network information and sub-network information according to the central network information, its own routing tables, and time slot usage criteria.