CN117440070B

CN117440070B - Method, device and equipment for mixed scheduling MAC protocol

Info

Publication number: CN117440070B
Application number: CN202311659897.4A
Authority: CN
Inventors: 潘晓鹤; 祝继锋; 国婧倩; 刘孟茁; 王国霖; 崔军红
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2023-12-06
Filing date: 2023-12-06
Publication date: 2024-03-08
Anticipated expiration: 2043-12-06
Also published as: CN117440070A

Abstract

The application discloses a method, a device and equipment for mixed scheduling MAC protocol, and relates to the technical field of underwater acoustic communication. Applied to an underwater hierarchical network, the method comprises the following steps: acquiring a network node in a target monitoring area of an underwater environment; constructing a communication and positioning integrated monitoring network by utilizing a network node and determining a corresponding available frequency band; dividing the available frequency bands to obtain at least two sub-frequency bands, and distributing the at least two sub-frequency bands to each node in a sub-network area connected with the water surface gateway node based on a preset distribution rule to obtain a target sub-network area corresponding to the water surface gateway node; each target subnet area comprises a subnet base station node and a plurality of terminal nodes; and executing a data transmission scheduling process through a subnet base station node in the target subnet area to acquire monitoring data of the terminal node, and forwarding the monitoring data to the mother ship node through a water surface network joint point. By the technical scheme, channel allocation can be optimized to improve the channel utilization rate.

Description

Method, device and equipment for mixed scheduling MAC protocol

Technical Field

The present invention relates to the field of underwater acoustic communications, and in particular, to a method, an apparatus, and a device for hybrid scheduling MAC protocol.

Background

Ocean is an important strategic space for national and national dependence on survival and sustainable development. With the continuous improvement of comprehensive national force and technological level, china is undergoing a transition from ocean major countries to ocean major countries, and in the process, the development of underwater technology must be paid attention to, and an underwater acoustic communication network is one of the basis and key technologies for developing ocean resources, protecting ocean environments and promoting ocean research.

Currently, the related solution to the problem of underwater acoustic channel allocation in the prior art mainly includes two MAC (Multiple Access Control ) protocols, TDMA (Time Division Multiple Access, time division multiple access) and FDMA (Frequency Division Multiple Access ). However, TDMA protocols have high clock synchronization requirements and are difficult to achieve in an underwater network; and when a node does not send data, the time slot allocated for the node is wasted, so that the channel utilization rate is low. The FDMA protocol has larger signal receiving and analyzing calculated amount when the frequency division is more, and has higher requirement on hardware; the underwater available bandwidth is narrow, so that the method has a large limit on the number of users; and when a node does not send data, the allocated channel is wasted, resulting in a situation of low channel utilization. It can be seen that the two MAC protocols have the problems of poor flexibility, complex algorithm, high requirement on hardware, mismatched application scenario, and the like, and are not suitable for large-scale underwater hierarchical networks.

Therefore, how to provide a solution to the above technical problem is a problem that a person skilled in the art needs to solve at present.

Disclosure of Invention

In view of the above, the present invention aims to provide a method, an apparatus and a device for hybrid scheduling MAC protocol, which can solve the problem of channel allocation of a multi-node shared underwater acoustic channel under a multi-layer network architecture of a large-scale underwater communication positioning integrated monitoring network, so as to effectively avoid data collision. The specific scheme is as follows:

in a first aspect, the present application discloses a hybrid scheduling MAC protocol method applied to an underwater hierarchical network, including:

determining a target monitoring area of an underwater environment, and acquiring network nodes in the target monitoring area; the network nodes comprise a mother ship node, a plurality of water surface gateway nodes and a plurality of underwater nodes; the underwater node comprises a subnet base station node and a terminal node;

constructing a communication and positioning integrated monitoring network by utilizing the network node, and determining a corresponding available frequency band based on the communication and positioning integrated monitoring network;

dividing the available frequency bands to obtain at least two sub-frequency bands, and distributing the at least two sub-frequency bands to each node in a sub-network area connected with the water surface gateway node based on a preset distribution rule to obtain a target sub-network area corresponding to the water surface gateway node; each target subnet area comprises one subnet base station node and a plurality of terminal nodes;

And executing a data transmission scheduling process in the target subnet area through the subnet base station node to acquire monitoring data of the terminal node, and forwarding the monitoring data to the mother ship node through the surface network node.

Optionally, the constructing a communication positioning integrated monitoring network by using the network node includes:

constructing a first layer network by using the mother ship node and the water surface gateway node;

constructing a second-layer network by utilizing the water surface gateway node and the subnet base station node;

constructing a third-layer network by utilizing the subnet base station node and a plurality of terminal nodes in the corresponding respective communication range of each subnet base station node in the target subnet area;

and determining the communication and positioning integrated monitoring network according to the first layer network, the second layer network and the third layer network.

Optionally, dividing the available frequency band to obtain at least two sub-frequency bands, and allocating the at least two sub-frequency bands to each node in a sub-network area connected with the water surface gateway node based on a preset allocation rule to obtain a target sub-network area corresponding to the water surface gateway node, which includes:

Dividing the available frequency band to obtain a first sub-frequency band and a second sub-frequency band;

and sequentially distributing the first sub-frequency band and the second sub-frequency band to each node in two sub-network areas connected with the water surface gateway node so as to obtain a target sub-network area corresponding to the water surface gateway node.

Optionally, executing a data transmission scheduling procedure by the subnet base station node in the target subnet area to obtain the monitoring data of the terminal node, and then forwarding the monitoring data to the mother ship node by the surface network node, including:

when the data transmission scheduling flow is an initialization stage, broadcasting a first scheduling packet to each terminal node through the subnet base station node in the target subnet area, so that the terminal node sequentially sends first node data to the subnet base station node according to the first scheduling packet and the sequence of a preset node sequence number; the corresponding time slot length when each terminal node sends the first node data to the sub-network base station node is determined based on the preset node sequence number, the maximum propagation delay and the maximum data transmission delay;

After receiving all first node data sent by the terminal node, the subnet base station node determines first position information corresponding to the terminal node by using the first node data according to an ultrashort baseline positioning principle through a positioning matrix carried by the subnet base station node;

forwarding the first position information and the first node data to the water surface gateway node by utilizing the current sub-frequency band corresponding to the target subnet area, and simultaneously monitoring the first position information and the first node data through the terminal node to determine a data transmission success event;

and based on the successful data transmission event, replying a confirmation character to the subnet base station node according to the current sub-frequency band through the water surface gateway node and forwarding the first position information and the first node data to the mother ship node through a water surface radio.

Optionally, after the terminal node monitors the first location information and the first node data to determine a successful data transmission event, the method further includes:

deleting the sent data corresponding to the data sending success event through the terminal node;

And if the terminal node does not determine the successful event of data transmission, re-triggering the step of forwarding the first position information and the first node data to the water surface gateway node by utilizing the current sub-band corresponding to the target sub-network area.

when the data transmission scheduling flow is a periodic data transmission stage, broadcasting a second scheduling packet to each terminal node through the subnet base station node in the target subnet area, so that the terminal node determines respective corresponding data transmission time sequences by utilizing the first position information according to the second scheduling packet, and transmitting second node data to the subnet base station node based on the data transmission time sequences;

after receiving all second node data sent by the terminal node, the subnet base station node determines second position information corresponding to the terminal node by using the second node data according to an ultrashort baseline positioning principle through a positioning matrix carried by the subnet base station node;

Forwarding the second position information and the second node data to the water surface gateway node by utilizing the current sub-frequency band corresponding to the target sub-network area, and simultaneously monitoring the second position information and the second node data through the terminal node to determine a successful data transmission event;

and based on the successful data transmission event, replying a confirmation character to the subnet base station node according to the current sub-frequency band through the water surface gateway node and forwarding the second position information and the second node data to the mother ship node through a water surface radio.

Optionally, the terminal node determines, according to the second scheduling packet, a data transmission timing sequence corresponding to each terminal node by using the first location information, and sends second node data to the subnet base station node based on the data transmission timing sequence, including:

based on the first position information, determining the propagation delay corresponding to each terminal node by using a preset propagation delay calculation formula;

sequencing the propagation delays according to the sequence from small to large, and determining the current time slot length corresponding to the time when the terminal node transmits the second node data to the subnet base station node according to the sequencing result and the transmission delay of the second node data to be transmitted by the terminal node;

And determining a data transmission time sequence corresponding to the terminal node according to the current time slot length, and sending second node data to the subnet base station node based on the data transmission time sequence.

Optionally, before the broadcasting, by the subnet base station node, the second scheduling packet to each of the terminal nodes in the target subnet area, the method further includes:

monitoring whether user instruction data sent by the mother ship node to the subnet base station node through the water surface gateway node exists or not;

and if the user instruction data exists, preprocessing the user instruction data and triggering the step of broadcasting a second scheduling packet to each terminal node through the subnet base station node in the target subnet area after the user instruction data is processed.

In a second aspect, the present application discloses a hybrid scheduling MAC protocol apparatus, applied to an underwater hierarchical network, comprising:

the node acquisition module is used for determining a target monitoring area of the underwater environment and acquiring network nodes in the target monitoring area; the network nodes comprise a mother ship node, a plurality of water surface gateway nodes and a plurality of underwater nodes; the underwater node comprises a subnet base station node and a terminal node;

The frequency band determining module is used for constructing a communication and positioning integrated monitoring network by utilizing the network node and determining a corresponding available frequency band based on the communication and positioning integrated monitoring network;

the frequency band dividing module is used for dividing the available frequency band to obtain at least two sub-frequency bands, and distributing the at least two sub-frequency bands to each node in a sub-network area connected with the water surface gateway node based on a preset distribution rule to obtain a target sub-network area corresponding to the water surface gateway node; each target subnet area comprises one subnet base station node and a plurality of terminal nodes;

and the data transmission module is used for executing a data transmission scheduling process through the subnet base station node in the target subnet area to acquire the monitoring data of the terminal node, and then forwarding the monitoring data to the mother ship node through the water surface network node.

In a third aspect, the present application discloses an electronic device comprising a processor and a memory; wherein the memory is configured to store a computer program that is loaded and executed by the processor to implement the hybrid scheduling MAC protocol method as described previously.

The application provides a mixed scheduling MAC protocol method which is applied to an underwater hierarchical network and comprises the following steps: determining a target monitoring area of an underwater environment, and acquiring network nodes in the target monitoring area; the network nodes comprise a mother ship node, a plurality of water surface gateway nodes and a plurality of underwater nodes; the underwater node comprises a subnet base station node and a terminal node; constructing a communication and positioning integrated monitoring network by utilizing the network node, and determining a corresponding available frequency band based on the communication and positioning integrated monitoring network; dividing the available frequency bands to obtain at least two sub-frequency bands, and distributing the at least two sub-frequency bands to each node in a sub-network area connected with the water surface gateway node based on a preset distribution rule to obtain a target sub-network area corresponding to the water surface gateway node; each target subnet area comprises one subnet base station node and a plurality of terminal nodes; and executing a data transmission scheduling process in the target subnet area through the subnet base station node to acquire monitoring data of the terminal node, and forwarding the monitoring data to the mother ship node through the surface network node.

The beneficial technical effects of this application are: dividing an available frequency band into at least two sub-frequency bands by utilizing the spatial distribution characteristics of the underwater hierarchical network, wherein different frequency bands are adopted between adjacent sub-networks so as to avoid data collision between the sub-networks; the monitoring data of each terminal node is obtained through the sub-network base station nodes according to the data transmission scheduling flow in the target sub-network area, the time sequence scheduling is optimized according to the monitoring data of each terminal node so as to optimize the channel allocation, and the channel utilization rate is improved while avoiding the data conflict in the sub-network. The mixed scheduling MAC protocol not only avoids algorithm complexity caused by excessive frequency division, but also avoids the limitation of the number of users caused by a method of only using frequency division; the clock synchronization requirement of the TDMA method is avoided, and the energy waste and the channel occupation caused by a large number of control packets of a pure reservation mechanism are avoided; and channel reservation, on-demand allocation and time scheduling are only carried out according to the obtained monitoring data, so that energy consumption is saved, and channel utilization rate is maximized.

In addition, the device and the equipment for the mixed scheduling MAC protocol correspond to the method for the mixed scheduling MAC protocol, and have the same effects.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

Fig. 1 is a flowchart of a method for hybrid scheduling MAC protocol disclosed in the present application;

fig. 2 is a schematic diagram of a communication positioning integrated monitoring network topology disclosed in the present application;

FIG. 3 is a flowchart of a specific hybrid scheduling MAC protocol method disclosed in the present application;

FIG. 4 is a flowchart of a specific hybrid scheduling MAC protocol method disclosed in the present application;

fig. 5 is a data transmission schedule diagram of a hybrid scheduling MAC protocol disclosed in the present application;

fig. 6 is a schematic structural diagram of a hybrid scheduling MAC protocol device disclosed in the present application;

fig. 7 is a block diagram of an electronic device disclosed in the present application.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

An underwater acoustic network (Underwater Acoustic Networks, UANs) is an interconnected distributed system of underwater multiple nodes connected by a number of underwater acoustic links. It consists of many kinds of underwater nodes that can sense and collect various information in the underwater environment, such as water temperature, water quality, water pressure, sound, flow rate, biological information, etc. The nodes are interconnected by underwater acoustic communication to form a network. The underwater acoustic network is generally used in the fields of ocean monitoring, ocean ecological research, ocean resource management, ocean disaster early warning and prevention, sea defense safety and the like. Due to the complexity and specificity of the underwater environment, the underwater acoustic network faces many challenges such as long delay, narrow bandwidth, complex and variable underwater acoustic channels, energy limitations, node deployment and positioning, etc. Therefore, designing and optimizing the underwater acoustic network requires consideration of these challenges and the adoption of protocol algorithms that adapt to the underwater environment.

The underwater acoustic network MAC protocol is a data link layer protocol of an underwater acoustic network, and refers to an underwater environment for managing and controlling the effective utilization of a shared underwater acoustic channel by underwater nodes. Due to the specificity of the underwater environment, the MAC protocol of the conventional terrestrial wireless network cannot be directly applied in the underwater acoustic network. Therefore, the design of the underwater MAC protocol needs to consider the characteristics of long delay, narrow bandwidth, high error code and the like of the underwater channel. The related prior art for solving the problem of underwater acoustic channel allocation mainly comprises two MAC protocols of TDMA and FDMA, and the two MAC protocols are as follows:

(1) TDMA: time slot division MAC protocol. In TDMA protocols, time is divided into time frames, each time frame being divided into a plurality of time slots of equal length, each time slot being allocated to a user. Different users transmit data in different time slots to avoid data collision. The protocol has higher requirement on clock synchronization, and is difficult to realize clock synchronization in an underwater network; and when a node does not send data, the time slot allocated for the node is wasted, so that the channel utilization rate is low.

(2) FDMA: frequency division MAC protocol. In the FDMA protocol, the available frequency band is divided into a plurality of sub-bands, each sub-band being allocated to one user. Different users transmit data with different sub-bands to avoid data collision. The method has the advantages that when the frequency division is more, the signal receiving and analyzing calculated amount is larger, and the requirement on hardware is higher; the underwater available bandwidth is narrow, so that the method has a large limit on the number of users; and when a node does not send data, the allocated channel is wasted, resulting in a situation of low channel utilization.

Therefore, the two related MAC protocols in the prior art have the problems of poor flexibility, complex algorithm, higher requirement on hardware, unmatched application scenes and the like.

Therefore, the application provides a mixed scheduling MAC protocol scheme which is suitable for an underwater multilevel network, can fully utilize the characteristics of hierarchical network topology, and organically combines and forms a new protocol algorithm mechanism to optimize channel allocation and improve the channel utilization rate on the premise of avoiding data collision.

The embodiment of the invention discloses a mixed scheduling MAC protocol method, which is shown in fig. 1 and is applied to an underwater hierarchical network, and the method comprises the following steps:

step S11: determining a target monitoring area of an underwater environment, and acquiring network nodes in the target monitoring area; the network nodes comprise a mother ship node, a plurality of water surface gateway nodes and a plurality of underwater nodes; the underwater nodes comprise a subnet base station node and a terminal node.

In the embodiment of the application, a target monitoring area of an underwater environment for monitoring is first determined, and network nodes needing to be monitored are determined in the target monitoring area. The network node may be composed of a buoy, submerged buoy, wave glider, underwater glider, unmanned ship, UUV (Unmanned Underwater Vehicle ) and other dynamic-static hybrid nodes. Dividing the network nodes to obtain nodes under a multi-layer network architecture so as to construct a large-scale underwater communication positioning integrated monitoring network.

In this embodiment of the present application, an application scenario is shown in fig. 2. The network nodes comprise 1 mother ship node, 4 water surface gateway nodes and a plurality of underwater nodes; the underwater nodes comprise a subnet base station node and a terminal node. Each subnet base station node has a plurality of terminal nodes corresponding to each other in the communication range. It can be understood that the number of the nodes provided in the scenario is only schematic, and the underwater coverage space of the network can be enlarged according to the actual situation, and the number of the network nodes is not limited, and in the following embodiments, the scenario is taken as an example to describe the network nodes, and details are not repeated.

Step S12: and constructing a communication and positioning integrated monitoring network by utilizing the network node, and determining a corresponding available frequency band based on the communication and positioning integrated monitoring network.

In the embodiment of the application, the acquired network nodes are utilized to construct a large-scale underwater communication and positioning integrated monitoring network, and as shown in fig. 2, the network is a three-layer network architecture. The first layer network consists of a mother ship node and a water surface gateway node; the second layer network consists of a water surface gateway node and a sub-network base station node; the third layer network is composed of sub-network areas, each sub-network area is composed of sub-network base station nodes and terminal nodes in the communication range. The monitoring data of all the underwater nodes are forwarded to the mother ship node through the water surface gateway node, and the mother ship node can also send an instruction to remotely control the underwater nodes.

In this embodiment of the present application, after the network node is used to construct the integrated monitoring network for communication positioning, the available frequency band is determined according to the communication distance in practical application, for example, in fig. 2, the communication distance is 10-15km, and then the available frequency band may be determined to be 9-16kHz.

Step S13: dividing the available frequency bands to obtain at least two sub-frequency bands, and distributing the at least two sub-frequency bands to each node in a sub-network area connected with the water surface gateway node based on a preset distribution rule to obtain a target sub-network area corresponding to the water surface gateway node; each target subnet area comprises one subnet base station node and a plurality of terminal nodes.

Specifically, by utilizing the spatial distribution characteristic of the hierarchical network, the available frequency band is divided into two sub-frequency bands F1 and F2. For example, the available frequency bands 9-16kHz can be divided into 9-12kHz, 13-16kHz. It should be noted that a certain guard interval is provided between two sub-bands, and the available frequency band can be divided into two sub-bands at will as long as a certain guard interval is provided between two sub-bands, and in practical application, suitable frequency bands can be selected in combination with factors such as network coverage requirements and influence between sub-networks.

In this embodiment, as shown in fig. 2, the two sub-bands are allocated to a water surface gateway node based on a preset allocation rule to obtain a sub-network area corresponding to the water surface gateway node. Specifically, the available frequency band is divided to obtain a first sub-frequency band and a second sub-frequency band; and sequentially distributing the first sub-frequency band and the second sub-frequency band to each node in two sub-network areas connected with the water surface gateway node so as to obtain a target sub-network area corresponding to the water surface gateway node. As shown in fig. 2, adjacent subnetwork areas use different frequency bands, and each water surface gateway node accesses two subnetworks. As in fig. 2, a water gateway 1 accesses a subnet 1 and a subnet 2; the subnet 1 adopts the frequency band F1, and the subnet 2 adopts the frequency band F2. The specific usage frequency bands for data transmission for each sub-network are noted above in fig. 2. Therefore, the data collision between the sub-network areas can be effectively avoided by adopting different frequency bands between the adjacent sub-networks.

Step S14: and executing a data transmission scheduling process in the target subnet area through the subnet base station node to acquire monitoring data of the terminal node, and forwarding the monitoring data to the mother ship node through the surface network node.

In the embodiment of the application, based on the sub-frequency bands divided by the steps, the data transmission scheduling process can be initiated by the sub-network base station node in each target sub-network area, so that the distributed hierarchical network architecture integrating underwater expandable communication and positioning is realized, and the large-area coverage of the underwater space and the positioning of the underwater nodes can be completed. The monitoring data of the terminal nodes in the corresponding sub-network areas can be acquired by the sub-network base station nodes through the data transmission scheduling flow in the target sub-network areas. After the sub-network base station node acquires the monitoring data, the monitoring data of all the underwater nodes are forwarded to the mother ship node through the water surface gateway node, and the mother ship node can also send an instruction to remotely control the underwater nodes.

It should be noted that the data and the positioning result information of all the nodes in the network can be collected to the central master control for storage analysis, and the central master control can regulate and control the nodes in the network according to the received data issuing instruction. Data interaction can also be performed between the network nodes, for example, collaborative monitoring detection can be performed between the mobile nodes through the data interaction.

In this embodiment, a specific expansion description is made on the data transmission scheduling flow. In a specific embodiment, when the data transmission scheduling process in the subnet area is the initialization phase, as shown in fig. 3, step S14 includes:

Step S1411: and broadcasting a first scheduling packet to each terminal node through the subnet base station node in the target subnet region, so that the terminal node sequentially sends first node data to the subnet base station node according to the first scheduling packet and the sequence of a preset node sequence number.

In the embodiment of the application, in the initialization stage, the distance from the terminal node to the subnet base station is unknown. Within the subnet area, the subnet base station node broadcasts a notification scheduling packet (Notification Scheduling, NS). The first scheduling packet contains time sequence scheduling information of data sent by each terminal node, and the time sequence scheduling information is related to the sequence of the node sequence numbers in an initialization stage and is sequentially sent.

It should be noted that, since the distance from each terminal node to the subnet base station node is unknown in the initialization stage, the slot length is determined based on the preset node sequence number and the maximum propagation delay and the maximum data transmission delay. It will be appreciated that propagation delay is related to distance and acoustic propagation velocity, and refers to the time taken for a signal transmitted by a transmitting node to propagate through an acoustic link to a receiving node at two nodes at different locations. The transmission delay is related to the data transmission rate and data length of the node, referring to the time it takes for the node to push data onto the underwater acoustic channel.

In the embodiment of the application, the time slot length is set to be the maximum propagation delayAnd maximum data transfer delay->And (d) is calculated. Specifically, after receiving the first scheduling packet, the terminal node follows the node sequence number: the first node directly transmits the first node data, and the second node waits +.>Then the first node data is sent, and the third node waits forAnd then sending the first node data, and so on. It can be understood that the scheduling packets broadcast by the subnet base station node to each terminal node in the corresponding subnet area in the initialization stage are all first scheduling packets; after receiving the first scheduling packet broadcast by the sub-network base station node, the terminal node returns the first node data.

Step S1412: and after receiving all the first node data sent by the terminal node, the subnet base station node determines first position information corresponding to the terminal node by using the first node data according to an ultrashort baseline positioning principle through a positioning matrix carried by the subnet base station node.

In the embodiment of the application, after receiving the first node data sent by all the terminal nodes, the subnet base station is carried with a positioning matrix, and the position information of each terminal node is calculated according to the ultra-short baseline positioning principle.

Step S1413: and forwarding the first position information and the first node data to the water surface gateway node by utilizing the current sub-frequency band corresponding to the target sub-network area, and simultaneously monitoring the first position information and the first node data through the terminal node to determine a successful data transmission event.

In the embodiment of the application, the subnet base station node forwards the received data information and the calculated position information of each node to the water surface gateway by adopting the frequency band allocated to the subnet base station node. Meanwhile, the terminal node monitors the data and the position information sent by the sub-network base station nodes to judge whether the data is sent successfully or not and confirm the distance between each terminal node and the sub-network base station nodes. It should be noted that, the listening manner is an implicit Acknowledgement mechanism, and compared with the traditional explicit Acknowledgement mechanism that the subnet base station node independently sends ACK (Acknowledgement character) to the terminal node, the implicit Acknowledgement mechanism reduces network delay, improves time efficiency and reduces energy consumption; the reliability of the data is guaranteed, and the transmission of additional control packets is reduced.

It should be noted that, when the subnet base station is used as a cluster head and the water surface gateway node sends data, the nodes in the subnet area can also receive the data, thereby achieving the effect of sending the ACK packet. If the terminal node in the subnet area does not receive the data, the next retransmission is needed to improve the success rate of data transmission; if the terminal node in the subnet receives the data, the terminal node deletes the transmitted data from the queue, which indicates that the transmission is successful before. In this way, the success rate of data transmission can be improved.

Specifically, deleting, by the terminal node, the transmitted data corresponding to the data transmission success event; and if the terminal node does not determine the successful event of data transmission, re-triggering the step of forwarding the first position information and the first node data to the water surface gateway node by utilizing the current sub-band corresponding to the target sub-network area.

Step S1414: and based on the successful data transmission event, replying a confirmation character to the subnet base station node according to the current sub-frequency band through the water surface gateway node and forwarding the first position information and the first node data to the mother ship node through a water surface radio.

In this embodiment of the present application, after receiving DATA sent by a subnet base station node, a water surface gateway node acknowledges with an ACK sent by the subnet base station node in the same frequency band, and if at this time the water surface gateway has DATA to send to the subnet base station node, the DATA is embedded into an ACK packet to send together. And then the monitoring data and the position information are forwarded to the mother ship node through the water surface radio. The adjacent subnets adopt different frequency bands to transmit data, so that data collision among the subnet areas can be avoided, and the two subnet base station nodes connected with the same water surface gateway node adopt different frequency bands, so that the data of the two subnet base station nodes can be prevented from collision in the water surface gateway.

In another specific embodiment, when the data transmission scheduling process is a periodic data transmission phase, as shown in fig. 4, step S14 includes:

step S1421: and broadcasting a second scheduling packet to each terminal node through the subnet base station node in the target subnet region, so that the terminal node determines the corresponding data transmission time sequence by utilizing the first position information according to the second scheduling packet, and sends second node data to the subnet base station node based on the data transmission time sequence.

After the initialization stage, each terminal node in the subnet area knows the distance information between the terminal node and the corresponding subnet base station node, and enters a periodical data transmission stage at the moment, and a second scheduling packet is broadcast to each terminal node in the target subnet area through the subnet base station node.

It should be noted that, in the period of periodic data transmission, the timing schedule calculation is downloaded to each terminal node, the timing schedule information is no longer included in the schedule packet, and the NS packet is transmitted only in the form of a preamble. Therefore, in the embodiment of the present application, in order to shorten the length as much as possible, improve the transmission success rate, reduce the energy consumption, only the preamble (preamble) is transmitted, that is, the front-most preamble of the data signal transmitted in the underwater acoustic communication is used for channel estimation. The type information of the second scheduling packet is encoded into the preamble with 2 bits (bits), thereby reducing the length of the second scheduling packet. The energy consumption is reduced, and the transmission success rate of the NS packet is improved. The type information of the second scheduling packet is used to distinguish which packet is at the receiving end, such as a DATA packet, an ACK packet, an NS packet, etc. And correspondingly processing different packets according to the type information receiving terminal.

In this embodiment of the present application, since the distance information between each terminal node and its subnet base station node is known in the periodic data transmission stage, after the NS packet is received, the data transmission timing sequence of each terminal node is calculated according to the first position information obtained before. Specifically, based on the first position information, determining propagation delays corresponding to the terminal nodes by using a preset propagation delay calculation formula; sequencing the propagation delays according to the sequence from small to large, and determining the current time slot length corresponding to the time when the terminal node transmits the second node data to the subnet base station node according to the sequencing result and the transmission delay of the second node data to be transmitted by the terminal node; and determining a data transmission time sequence corresponding to the terminal node according to the current time slot length, and sending second node data to the subnet base station node based on the data transmission time sequence.

The preset propagation delay calculation formula is as follows:；/>representing propagation delay; />Representing a subnetThe moment when the base station node receives the data of each terminal node; />Indicating the time when the sub-network base station node transmits the NS packet; />Representing the transmission delay of NS packets; />Representing the transmission delay of each terminal node DATA packet; / >Representing the waiting time for each end node to receive the NS packet until the data is transmitted.

Further, the method comprises the steps of,the transmission delay calculation formula of (1) is: />The method comprises the steps of carrying out a first treatment on the surface of the Wherein (1)>Representing the length of DATA>The data transmission rate of a node is usually a constant value in relation to the modulation and coding scheme of the physical layer.

When the propagation delays corresponding to the end nodes are determined, the propagation delays are first ordered, e.g. the propagation delays of the end nodes 1, 2, 3 are ordered as. Then, node 1 directly transmits data after receiving the NS packet, and node 2 waits +.>Then data is sent; wherein (1)>For the transmission delay of node 1 data, +.>Is a guard interval. Node 3 waits +.>Then data is sent; wherein (1)>Is the data transmission delay of node 2. And so on.

It should be noted that, each data packet transmitted by each terminal node includes the data length information of the next transmission) The transmission delays of the data with different lengths are different, and the calculated waiting time is also different. The data packet sent in this round contains the data length information sent next time, so that the rest terminal nodes can calculate the waiting time from the time when the rest terminal nodes receive the NS packet to the time when the rest terminal nodes send the data in the next round of transmission, so as to optimize the channel resource allocation.

Step S1422: after receiving all second node data sent by the terminal node, the subnet base station node determines second position information corresponding to the terminal node by using the second node data according to an ultrashort baseline positioning principle through a positioning matrix carried by the subnet base station node;

step S1423: forwarding the second position information and the second node data to the water surface gateway node by utilizing the current sub-frequency band corresponding to the target sub-network area, and simultaneously monitoring the second position information and the second node data through the terminal node to determine a successful data transmission event;

step S1424: and based on the successful data transmission event, replying a confirmation character to the subnet base station node according to the current sub-frequency band through the water surface gateway node and forwarding the second position information and the second node data to the mother ship node through a water surface radio.

For more specific processing procedures of the steps S1422, S1423, and S1423, reference may be made to the corresponding contents disclosed in the foregoing embodiments, and no further description is given here.

In addition, it should be noted that, when the subnet base station node starts each round of data transmission stage, that is, before broadcasting the NS packet, if there is instruction data to be sent to a certain terminal node below the subnet base station node, the instruction data refers to user data sent to the subnet base station by the mother ship through the water surface gateway, instead of a packet created by the MAC protocol layer, the data needs to be sent before broadcasting the NS packet, and after the data transmission is finished, the NS packet is started to be broadcasted, and a new round of data transmission is started. Specifically, before broadcasting a second scheduling packet to each terminal node through the subnet base station node in the target subnet area, monitoring whether user instruction data sent by the mother ship node to the subnet base station node through the water surface gateway node exists; and if the user instruction data exists, preprocessing the user instruction data and triggering the step of broadcasting a second scheduling packet to each terminal node through the subnet base station node in the target subnet area after the user instruction data is processed.

An on-demand hybrid scheduling MAC protocol flow diagram for an underwater hierarchical network is implemented using the content of the above embodiments to advantage as shown in fig. 5. Instead of simple FDMA, TDMA or reservation mechanisms, the characteristics of hierarchical network topology are utilized to organically combine FDMA, timing scheduling and reservation mechanisms to form a new protocol algorithm mechanism. In the initialization phase: the sub-network base station node broadcasts an NS packet, wherein the NS packet contains the data transmission time sequence information of each terminal node; after receiving the NS packet, the terminal node analyzes the respective data transmission time sequence and transmits data to the sub-network base station node at the respective time sequence; receiving data of all terminal nodes by the sub-network base station nodes and calculating position information of each terminal node; and then the received data information and the position information of each terminal node are sent to a water surface gateway, and the water surface gateway receives the information reply ACK and the instruction data. During the periodic data transmission phase, the subnet base station node broadcasts NS packets (only the preamble); the terminal node receives the NS packet and calculates respective data transmission time sequences according to the length information and the position information of the data to be transmitted by each node monitored in the previous stage; the terminal nodes send data at respective time sequences; and when the subnet base station node receives the data of all the terminal nodes, calculating the position information of each terminal node. Similarly, the subnet base station node sends the received data information and the position information of each terminal node to the water surface gateway, and the water surface gateway receives the information reply ACK and the instruction data.

Therefore, aiming at the distributed hierarchical network architecture, the on-demand mixed scheduling MAC protocol method in the embodiment of the application optimizes channel scheduling by using the calculated node position information and the information of the respective data quantity, thereby achieving the purpose of avoiding conflict, avoiding time synchronization and improving the channel utilization rate. On the other hand, network delay and energy consumption are reduced, so that the underwater wireless sensor network is more efficient. In the periodical data transmission stage, the transmission time of the NS packet can be reduced by shortening the NS packet, so that the network delay and the energy consumption are reduced; different sub-networks of the same gateway are adopted by the sub-network base station and the gateway to transmit at different frequencies, and the network delay can be reduced as well. The network delay and the energy consumption can be reduced without sending an ACK packet in the subnet.

Correspondingly, the embodiment of the application also discloses a hybrid scheduling MAC protocol device, which is applied to an underwater hierarchical network, as shown in fig. 6, and the device comprises:

the node acquisition module 11 is used for determining a target monitoring area of the underwater environment and acquiring network nodes in the target monitoring area; the network nodes comprise a mother ship node, a plurality of water surface gateway nodes and a plurality of underwater nodes; the underwater node comprises a subnet base station node and a terminal node;

The frequency band determining module 12 is configured to construct a communication positioning integrated monitoring network by using the network node, and determine a corresponding available frequency band based on the communication positioning integrated monitoring network;

the frequency band division module 13 is configured to divide the available frequency band to obtain at least two frequency sub-bands, and allocate the at least two frequency sub-bands to each node in a subnet area connected to the water surface gateway node based on a preset allocation rule to obtain a target subnet area corresponding to the water surface gateway node; each target subnet area comprises one subnet base station node and a plurality of terminal nodes;

and the data transmission module 14 is configured to execute a data transmission scheduling procedure in the target subnet area through the subnet base station node to obtain the monitoring data of the terminal node, and then forward the monitoring data to the mother ship node through the surface network node.

The more specific working process of each module may refer to the corresponding content disclosed in the foregoing embodiment, and will not be described herein.

It can be seen that, by the above scheme of the present embodiment, the method is applied to an underwater hierarchical network, and includes: determining a target monitoring area of an underwater environment, and acquiring network nodes in the target monitoring area; the network nodes comprise a mother ship node, a plurality of water surface gateway nodes and a plurality of underwater nodes; the underwater node comprises a subnet base station node and a terminal node; constructing a communication and positioning integrated monitoring network by utilizing the network node, and determining a corresponding available frequency band based on the communication and positioning integrated monitoring network; dividing the available frequency bands to obtain at least two sub-frequency bands, and distributing the at least two sub-frequency bands to each node in a sub-network area connected with the water surface gateway node based on a preset distribution rule to obtain a target sub-network area corresponding to the water surface gateway node; each target subnet area comprises one subnet base station node and a plurality of terminal nodes; and executing a data transmission scheduling process in the target subnet area through the subnet base station node to acquire monitoring data of the terminal node, and forwarding the monitoring data to the mother ship node through the surface network node.

Further, the embodiment of the present application further discloses an electronic device, and fig. 7 is a block diagram of the electronic device 20 according to an exemplary embodiment, where the content of the figure is not to be considered as any limitation on the scope of use of the present application.

Fig. 7 is a schematic structural diagram of an electronic device 20 according to an embodiment of the present application. The electronic device 20 may specifically include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input output interface 25, and a communication bus 26. Wherein the memory 22 is configured to store a computer program that is loaded and executed by the processor 21 to implement relevant steps in the hybrid scheduling MAC protocol method disclosed in any of the foregoing embodiments.

In this embodiment, the power supply 23 is configured to provide an operating voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and an external device, and the communication protocol to be followed is any communication protocol applicable to the technical solution of the present application, which is not specifically limited herein; the input/output interface 25 is used for acquiring external input data or outputting external output data, and the specific interface type thereof may be selected according to the specific application requirement, which is not limited herein.

The memory 22 may be a carrier for storing resources, such as a read-only memory, a random access memory, a magnetic disk, or an optical disk, and the resources stored thereon may include an operating system 221, a computer program 222, data 223, and the like, and the data 223 may include various data. The storage means may be a temporary storage or a permanent storage.

The operating system 221 is used to manage and control various hardware devices on the electronic device 20 and the computer program 222. The computer program 222 may further comprise a computer program capable of performing other specific tasks in addition to the computer program capable of performing the hybrid scheduling MAC protocol method performed by the electronic device 20 as disclosed in any of the previous embodiments.

Further, embodiments of the present application disclose a computer readable storage medium, where the computer readable storage medium includes random access Memory (Random Access Memory, RAM), memory, read-Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, magnetic disk, or optical disk, or any other form of storage medium known in the art. Wherein the computer program, when executed by a processor, implements the aforementioned hybrid scheduling MAC protocol method. For specific steps of the method, reference may be made to the corresponding contents disclosed in the foregoing embodiments, and no further description is given here.

In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, so that the same or similar parts between the embodiments are referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.

The steps of a hybrid scheduling MAC protocol method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software modules may be disposed in Random Access Memory (RAM), memory, read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The above description of the method, the device and the equipment for mixed scheduling MAC protocol provided by the present invention applies specific examples to illustrate the principles and the implementation of the present invention, and the description of the above examples is only used to help understand the method and the core idea of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present invention, the present description should not be construed as limiting the present invention in view of the above.

Claims

1. A hybrid scheduling MAC protocol method, applied to an underwater hierarchical network, comprising:

Executing a data transmission scheduling process in the target subnet area through the subnet base station node to acquire monitoring data of the terminal node, and then forwarding the monitoring data to the mother ship node through the surface network node;

executing a data transmission scheduling process by the subnet base station node in the target subnet area to obtain monitoring data of the terminal node, and forwarding the monitoring data to the mother ship node by the surface network node, wherein the method comprises the following steps:

2. The hybrid-scheduling MAC protocol method of claim 1, wherein the constructing a communication-location-integrated monitoring network using the network node comprises:

3. The method according to claim 1, wherein dividing the available frequency band to obtain at least two frequency sub-bands, and assigning the at least two frequency sub-bands to each node in a subnet area connected to the water surface gateway node based on a preset allocation rule to obtain a target subnet area corresponding to the water surface gateway node, comprises:

4. The hybrid-scheduling MAC protocol method of claim 1, wherein after the first location information and the first node data are monitored by the terminal node to determine a data transmission success event, further comprising:

5. The hybrid-scheduling MAC protocol method of claim 1, wherein performing a data transmission scheduling procedure by the subnet base station node to obtain the monitoring data of the terminal node in the target subnet area, and then forwarding the monitoring data to the parent ship node by the surface network node comprises:

6. The hybrid-scheduling MAC protocol method of claim 5, wherein the terminal node determining, according to the second scheduling packet, a data transmission timing sequence corresponding to each of the first location information, and transmitting second node data to the subnet base station node based on the data transmission timing sequence, comprising:

7. The hybrid-scheduling MAC protocol method of claim 5, wherein before broadcasting the second scheduling packet to each of the terminal nodes by the subnet base station node within the target subnet area, further comprising:

8. A hybrid scheduling MAC protocol apparatus for use in an underwater hierarchical network, comprising:

the data transmission module is used for executing a data transmission scheduling process through the subnet base station node in the target subnet area to acquire monitoring data of the terminal node, and then forwarding the monitoring data to the mother ship node through the water surface network node;

the data transmission module is specifically configured to:

9. An electronic device comprising a processor and a memory; wherein the memory is for storing a computer program to be loaded and executed by the processor to implement the hybrid scheduling MAC protocol method of any one of claims 1 to 7.