Multi-channel communication method and system based on narrow-band fishing ad hoc network

Abstract

The invention relates to the technical field of wireless communication, in particular to a multichannel communication method and system based on a narrowband fishing ad hoc network, and the method comprises the steps: carrying out clustering according to the dynamic distance between ship nodes and a base station, enabling the nodes in the same cluster to share a data channel, and enabling different clusters to distribute orthogonal channels to form a multichannel topological structure. A node synchronously obtains a data channel number and a TDMA time slot allocation scheme through a clustering process, and calculates HELLO message sending offset time of a control channel based on the channel number and a time slot position, thereby realizing time division multiplexing of inter-cluster control information. The HELLO message carries node positions, addresses and channel configuration information and is used for maintaining network topology awareness. A dual-channel separation mechanism is adopted in the data transmission stage, a node sends data in a data channel, HELLO messages are transmitted through a control channel, and competition conflicts of the control channel are avoided.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and particularly to a multi-channel communication method and system based on a narrow-band fishing self-organizing network. Background Art

[0002] Fishing communication systems are usually used for voice communication, with a relatively low bandwidth, a half-duplex structure, and have mutually independent control channels and data channels. Among them, the control channel is in a fixed frequency band, while the data channel can be changed by changing the intermediate frequency of the transceiver. Both of these two channels can receive signals synchronously, but cannot send signals in parallel. For this special communication structure, most of the existing MAC protocols and routing protocols cannot be adapted.

[0003] Currently, there are also some networking methods for specific fishing communication systems. By increasing the communication bandwidth and using additional base station management, etc., effective networking can be achieved, but there are still deficiencies in the adaptability to distributed systems and low bandwidth. For example, in the paper titled "Research on Multi-channel Multi-slot Autonomous Access Algorithm for Maritime Broadband Voice Self-organizing Network", a multi-channel multi-slot autonomous access algorithm is proposed. This algorithm realizes signaling negotiation on the control channel, and this method is not applicable to narrow-band multi-channel networks. The patent document with the application publication number CN111491285A proposes a control system and method for maritime Ad hoc networking communication, which uses a clustering structure for networking. When working normally, the low-speed communication module of the system is used for network maintenance, and the high-speed communication module is used to undertake network service communication. When the high-speed communication module is abnormal or busy, the low-speed communication module can be used to realize emergency short message, AIS, and voice communication, achieving self-organizing networking without using additional communication equipment. However, this method uses two rates, high-speed and low-speed, with a maximum of 800 kbps, and does not solve the networking problem under lower bandwidth. Through the above analysis, the existing technical means and the already applied-for invention patents do not give a solution to the multi-channel networking access scheme in narrow-band wireless networks. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a multi-channel communication method and system based on a narrow-band fishing self-organizing network for solving the technical problem of low network communication efficiency existing in the prior art.

[0005] The object of the present invention is achieved by the following technical solutions: In a first aspect, the present invention provides a multi-channel communication method based on a narrow-band fishing self-organizing network, including: Taking the location of the ship as a node, clustering the data channels according to the distance between the node and the shore station; nodes within the same cluster use the same data channel, and multiple data channels form a network topology; The node determines the channel number of the data channel and the access time slot of the control channel through clustering; the node uses the data channel to transmit data; According to the channel number and the access time slot of the control channel, determine the relative offset time for the node to send a HELLO message on the control channel; the HELLO message includes the location of the node, the node address, and the channel number currently used by the data channel; The node determines whether the current moment is its own access time slot. If it is its own access time slot, perform backoff timing according to the relative offset time.

[0006] As a further improvement of the present invention, clustering is performed according to the distance between the node and the shore station, specifically including: Each node obtains its own location information, and based on the distance between its own location information and the shore station, calculates its own cluster number based on the distance clustering algorithm; the clustering calculation method is:

[0007] In the formula, is the distance between the node and the shore station, is the clustering step size, is the number of data channels used in the network, represents the modulo operation.

[0008] As a further improvement of the present invention, determining the relative offset time for the node to send a HELLO message on the control channel specifically includes: The relative offset time of the node is:

[0009]

[0010]

[0011] In the formula, is the relative offset time of the node, is the probability distribution function; is, is the connection line between the node and the shore station, is the angle between the axis.

[0012] As a further improvement of the present invention, the node is used to broadcast a HELLO message according to the relative offset time and time slot, and obtain neighbor node information in real time, and store the neighbor node information in the neighbor list.

[0013] As a further improvement of the present invention, when a node needs to send a route request to a target node, the target node exists in the neighbor list of the node: Fill the channel field of the routing request message with the data channel where the current node is located; and query the channel where the target node is located, and jump to the channel where the target node is located to unicast the routing request message. After receiving the routing request, the target node returns a routing reply through the original path, and the routing is established.

[0014] As a further improvement of the present invention, when a node needs to send a routing request to a target node and the target node does not exist in the neighbor list of the node: The node fills the channel field of the routing request message with the data channel where the current node is located, and the four nodes with the maximum values in four directions among the neighbor nodes in the same cluster; Fill the forwarding node field in the routing request in the node; Broadcast within the cluster where the node is located, and designate the node as the forwarding node, forward the routing request to the target node in a unicast manner, and update its own forwarding node at the same time; After receiving the routing request, the target node returns a routing reply through the original path, and the routing is established.

[0015] As a further improvement of the present invention, when a node or a forwarding node does not have neighbor nodes in the same cluster, the standard AODV routing protocol is used to forward the routing information to the target node.

[0016] In a second aspect, the present invention provides a multi-channel communication system based on a narrowband fishing ad hoc network, including: A node clustering module, which takes the location of the ship as a node and clusters the data channels according to the distance between the node and the shore station; nodes in the same cluster use the same data channel, and multiple data channels form a network topology; A node channel binding module, where the node determines the channel number of the data channel and the access time slot of the control channel through clustering; A message interaction module, which determines the relative offset time for the node to send a HELLO message on the control channel according to the channel number and the access time slot of the control channel; the HELLO message includes the location of the node, the node address, and the channel number of the current data channel used; A dual-channel data transmission module, where the node uses the data channel to transmit data; the node determines whether the current moment is its own access time slot, and if it is its own access time slot, it sends a HELLO message and performs backoff timing according to the relative offset time.

[0017] As a further improvement of the present invention, the system adopts a dual-MCU architecture, and the dual-MCU architecture includes a main MCU and a secondary MCU; the main MCU is used for control channel interaction and system coordination, and the secondary MCU is used for voice encoding and decoding and data channel listening of the dual-channel radio frequency module.

[0018] As a further improvement of the present invention, the access to the data channel adopts the CSMA / CA protocol for access.

[0019] In a third aspect, the present invention provides a computer-readable storage medium storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to execute the above-mentioned multi-channel communication method based on a narrowband fishing ad-hoc network.

[0020] In a fourth aspect, the present invention provides a computing device, including: One or more processors, a memory, and one or more programs, where the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include steps for executing the above-mentioned multi-channel communication method based on a narrowband fishing ad-hoc network.

[0021] The beneficial effects of the present invention are as follows: The present invention provides a multi-channel communication method based on a narrowband fishing ad-hoc network. By clustering vessel nodes that are close to each other into the same data channel, channel conflicts between different clusters can be effectively reduced, and channel utilization can be improved. Multiple data channels work in parallel to achieve multiplexing of spectrum resources and enhance the overall network capacity. By controlling the allocation of channel access time slots, the situation where multiple nodes send HELLO messages simultaneously can be avoided, the collision probability can be reduced, and the access efficiency can be improved. HELLO messages are sent regularly to ensure timely update of node location information and support dynamic routing and topology management. When data is transmitted during its own access time slot, backoff timing is performed according to the relative offset time to reduce conflicts and improve the reliability of data transmission. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a schematic structural diagram of a fishing communication system applicable to the present invention.

[0024] Figure 2 It is a flowchart of the implementation of the multi-channel access method of the present invention.

[0025] Figure 3 It is a flowchart of the implementation of the routing strategy of the present invention.

[0026] Figure 4 It is a schematic diagram of the node distribution of the simulated vessels of the present invention.

[0027] Figure 5 It is a schematic diagram for comparing the results of testing the throughput of the simulation platform of the present invention.

[0028] Figure 6 It is a schematic diagram for comparing the results of testing the end-to-end delay of the simulation platform of the present invention.

[0029] Figure 7 It is a schematic diagram for comparing the results of testing the packet loss rate of the simulation platform of the present invention. Detailed implementation manners

[0030] In order to make the objectives and technical solutions of the present invention clearer and easier to understand, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. Among them, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0032] Embodiment 1 This embodiment provides a multi-channel communication method based on a narrowband fishing ad-hoc network. The following are the specific implementation manners.

[0033] First, the location of the ship is used as a node, and the data channels are clustered according to the distance between the node and the shore station; the nodes within the same cluster use the same data channel, and multiple data channels form a network topology. The channels in this embodiment include data channels and control channels. The data channels are mainly used for transmitting data, while the control channels are mainly used for transmitting HELLO messages. The HELLO message includes the location of the node, the node address, and the channel number used by the current data channel.

[0034] Each node is connected to the data channel respectively, specifically including: the node determines the channel number of the data channel and the access time slot of the control channel through clustering.

[0035] Each node obtains its own location information, and calculates its own cluster number based on the distance clustering algorithm according to the distance between its own location information and the shore station; the clustering calculation method is:

[0036] In the formula, is the distance between the node and the shore station, is the clustering step size, is the number of data channels used in the network, represents the modulo operation. Clustering by distance can effectively reduce the interference between long-distance nodes.

[0037] As the ship moves, the distance between the nodes and the shore station changes. Therefore, in this embodiment, each node periodically updates its own cluster and the next data channel, and dynamically adjusts the cluster to maintain the stability of the network.

[0038] After the node accesses, according to the channel number and the control channel access time slot, determine the relative offset time for the node to send a HELLO message on the control channel; The node determines whether the current moment is its own access time slot. If it is its own access time slot, it sends a HELLO message for transmission and performs backoff timing according to the relative offset time.

[0039] In this embodiment, the relative offset time of the node is:

[0040]

[0041]

[0042] In the formula, is the relative offset time of the node, is the probability distribution function; is, is the angle between the line connecting the node and the shore station and the axis.

[0043] The node is used to broadcast a HELLO message according to the relative offset time and the time slot, and obtain neighbor node information in real time, and store the neighbor node information in the neighbor list When a node needs to send a route request to a target node, if the target node exists in the neighbor list of this node, fill in the data channel where the current node is located in the channel field of the route request message; and query the channel where the target node is located, and jump to the channel where the target node is located to unicast the route request message; After receiving the route request, the target node returns a route reply through the original path, and the route is established When a node needs to send a route request to a target node, and the target node does not exist in the neighbor list of this node, the node fills in the data channel where the current node is located in the channel field of the route request message, and selects the four nodes with the maximum values in the four directions among the neighbor nodes in the same cluster; fill in the forwarding node field in the route request in the node; broadcast within the cluster where the node is located, and designate the node as the forwarding node, and forward the route request to the target node in a unicast manner, and update its own forwarding node at the same time; after receiving the route request, the target node returns a route reply through the original path, and the route is established.

[0044] When there are no neighbor nodes in the same cluster for a node or a forwarding node, the standard AODV routing protocol is used to forward the routing information to the destination node.

[0045] Embodiment 2 Refer to Figure 1 , which is a schematic diagram of the communication system structure of a narrowband half-duplex digital fishing station. This system is half-duplex and can receive two parallel signals. One is a control channel fixed at 33.3 MHz, and the other is a data channel with a frequency range of 27.5 MHz to 39.5 MHz. The channel bandwidth is 9.6 kbps. The main MCU is responsible for listening and receiving on the control channel and interacting with the Android system. The secondary MCU is used for voice and signaling encoding and decoding operations, while also listening to the data channel and uploading the received data to the main MCU. The Android system is mainly used to provide a UI interface and complete some data processing functions.

[0046] Among them, the multi-channel access method works between the main MCU and the secondary MCU, and the routing protocol works in the Android system, coordinating with each other to complete. According to Figure 1 The shown communication system, its multi-channel access method includes the access of the control channel and the access of the data channel. Among them, the access of the control channel adopts a reservation-based access scheme, which is completed through the allocation of different time slots and the backoff after time slot access. The access of the data channel adopts the CSMA / CA protocol for access. The control channel is mainly used to transmit periodic HELLO messages. The HELLO message carries the geographical location, node address, and the channel number of the current data channel used by the node.

[0047] The process of the multi-channel access method is as shown in Figure 2 and includes the following steps: After each node boots up, it executes its own initialization program. It needs to obtain its own location information through the GPS module in Figure 1 , and then convert the longitude and latitude coordinates into rectangular coordinates. The coordinate origin, that is, the reference point, is selected as the location coordinates of the shore station.

[0048] The node starts to calculate its own cluster periodically. First, it calculates the distance between the node and the shore station (km), selects the cluster step size (km), the number of data channels used for networking is , the cluster number is , then the cluster calculation method is:

[0049] where mod represents the modulo operation. By taking the modulo with the number of channels and adding one, the number between ~ can be obtained. When is selected relative to When it is smaller, the node clustering results in the network are relatively uniform.

[0050] Nodes determine the channel number of the data channel and the access time slot of the control channel through clustering. Each node uses the channel and time slot respectively as:

[0051]

[0052] The duration of each time slot is , the time frame period is , and the access opportunity is , =0, 1, 2, 3….

[0053] Nodes judge whether the current moment is their own access time slot. If it reaches the time slot corresponding to the current clustering, they will perform backoff timing. Given the shore station position and node position , the angle between the connection line between the node and the shore station and the axis can be obtained as:

[0054] where , and according to the real position data of the ship near the sea, the probability density function between any node and the ship distribution can be obtained , then its probability distribution function is . According to the probability integral transformation principle, obeys the uniform distribution on. Thus, we can obtain the backoff time . Its purpose is to reserve 0.1 seconds of idle time slots in each time slot for some special demand scenarios. The transmission time of the node ensures the equal-probability access of each node.

[0055] As Figure 3 shown, the routing strategy includes the following steps: Step 1), when the node is powered on, it will periodically send HELLO messages on the control channel using the Figure 2 described algorithm process and continuously receive HELLO messages from neighbors. The HELLO message contains the geographical location, node address, and the channel number of the current data channel used by this node. The received HELLO messages will be retained in the neighbor list and the neighbor list will be refreshed periodically.

[0056] Step 2) When there is traffic arriving, the source node first queries the neighbor list. If the destination node appears in the neighbor list, the source node fills the channel field in the RREQ message with the data channel where the current node is located. Then, it queries the channel where the destination node is located in the neighbor list and jumps to that channel to unicast the RREQ message, avoiding flooding. After sending, it jumps back to the original channel. When the destination node receives the unicast RREQ, it jumps to the channel corresponding to the channel field in the RREQ to reply with an RREP, and the routing is established.

[0057] Step 3) If the destination node is not in the neighbor list of the source node, a route search is needed. At this time, the source node fills the channel field in the RREQ message with the data channel where the current node is located and searches for four nodes with the maximum values in four directions among the neighbors in the same cluster, and fills them into the forwarding node field in the RREQ. Only the nodes specified as forwarding nodes can forward the routing message. When a node receives an RREQ message, it checks whether the destination node is in its neighbor list. If so, it jumps to the channel where the destination node is located to unicast the RREQ message, jumps back to the original channel after sending, waits for the reply of the RREP and forwards it back to the source node. If not, it checks whether it is a specified forwarding node. If so, it forwards the message and updates its forwarding node at the same time. If not, it discards the message. If there are no neighbor nodes in the same cluster for the source node or the forwarding node, it means that the node density is relatively sparse. At this time, it degrades to the standard AODV routing protocol, and the routing discovery process is carried out on the control channel. At this time, 0.1 seconds reserved for each frame of the control channel is used to transmit routing information.

[0058] Refer to

[0059] Refer to Figure 4 which is the schematic diagram of the ship distribution used in the simulation. Generate a topology scenario according to this distribution on the NS2 simulation platform, set the ship speed to a random value between 0 - 5 m / s, the ship communication radius to 80 km, the clustering step is selected as 1 km, the number of data channels is 10, the duration of each time slot is 6 seconds, the entire time frame period is 60 seconds, and the channel bandwidth is set to 9.6 kbps. Randomly select 6 nodes, with a total of 3 cbr data streams. Simulate the performance such as throughput, delay, and packet loss rate.

[0060] As Figure 5 shown in Figure 6The comparison results of end-to-end delay for using multiple data channels (10), single-hop data channels, IEEE 802.11, and the standard AODV protocol. Figure 7 The comparison results of packet loss rate for using multiple data channels (10), single-hop data channels, IEEE 802.11, and the standard AODV protocol.

[0061] It can be seen that after adopting the multi-channel access and routing method of the present invention, the throughput, delay, and packet loss rate of the network have been greatly improved compared with IEEE 802.11 and the standard AODV protocol.

[0062] Embodiment 3 This embodiment provides a multi-channel communication system based on a narrowband fishing ad hoc network. The system specifically includes a node clustering module that uses the location of the vessel as a node and clusters the data channels according to the distance between the node and the shore station; nodes within the same cluster use the same data channel, and multiple data channels form a network topology. A node channel binding module that determines the channel number of the data channel and the access time slot of the control channel through clustering. A message interaction module that determines the relative offset time for the node to send a HELLO message on the control channel according to the channel number and the access time slot of the control channel; the HELLO message includes the location of the node, the node address, and the channel number used by the current data channel. A dual-channel data transmission module that the node uses the data channel to transmit data; the node determines whether the current moment is its own access time slot. If it is its own access time slot, it sends a HELLO message and performs backoff timing according to the relative offset time.

[0063] This system adopts a dual-MCU architecture, and the dual-MCU architecture includes a main MCU and a secondary MCU; the main MCU is used for control channel interaction and system coordination, and the secondary MCU is used for voice encoding / decoding and data channel monitoring of the dual-channel radio frequency module. The access protocol of the data channel adopts the CSMA / CA protocol.

Claims

1. A multi-channel communication method based on a narrowband fishing ad hoc network, characterized in that: include: The location of the ship is taken as a node, and the data channels are clustered according to the distance between the node and the shore station; Nodes in the same cluster use the same data channel, and multiple data channels form a network topology; The node determines the channel number of the data channel and the control channel access time slot by clustering; the node transmits data using the data channel; Determine the relative offset time for the node to send a HELLO message on the control channel according to the channel number and the control channel access time slot; the HELLO message includes the location of the node, the node address and the channel number used by the current data channel; The node determines whether the current time is its own access time slot. If it is its own access time slot, it performs backoff timing according to the relative offset time.

2. The multi-channel communication method based on narrowband fishing ad hoc network according to claim 1, characterized in that: Clustering is performed based on the distance between the node and the shore station, including: Each node obtains its own location information, and calculates its own cluster number based on the distance clustering algorithm according to the distance between its own location information and the shore station. The clustering calculation method is: In the formula, is the distance between the node and the shore station, is the clustering step size, The number of data channels used by the network. Represents a modulo operation.

3. The multi-channel communication method based on narrowband fishing ad hoc network according to claim 1, characterized in that: Determine the relative offset time for the node to send the HELLO message on the control channel, specifically including: The relative offset time of the node is: In the formula, is the relative offset time of the node, is the probability distribution function; for, The connection between the node and the shore station, The angle between the axes.

4. The multi-channel communication method based on narrowband fishing ad hoc network according to claim 1, characterized in that: The node is used to broadcast a HELLO message according to the relative offset time and time slot, and obtain neighbor node information in real time, and store the neighbor node information in a neighbor list.

5. The multi-channel communication method based on narrowband fishing ad hoc network according to claim 4 is characterized in that: When a node needs to send a routing request to a target node, the target node exists in the node's neighbor list: Fill in the data channel where the current node is located in the channel field of the route request message; query the channel where the target node is located, jump to the channel where the target node is located and unicast the route request message; After receiving the routing request, the target node returns the routing reply through the original path, and the routing is established.

6. The multi-channel communication method based on narrowband fishing ad hoc network according to claim 4, characterized in that: When a node needs to send a routing request to a target node, and the target node does not exist in the node's neighbor list: The node fills in the data channel where the current node is located in the channel field of the routing request message, and selects the four nodes with the maximum values ​​in four directions among the neighbor nodes in the same cluster; Filling the forwarding node field in the routing request in the node; Broadcast within the cluster where the node is located, designate the node as a forwarding node, forward the routing request to the target node in unicast mode, and update its own forwarding node at the same time; After receiving the routing request, the target node returns the routing reply through the original path, and the routing is established.

7. The multi-channel communication method based on narrowband fishing ad hoc network according to claim 4, characterized in that: When a node or forwarding node does not have neighboring nodes in the same cluster, the standard AODV routing protocol is used to forward routing information to the target node.

8. A multi-channel communication system based on a narrowband fishing ad hoc network, characterized in that: include: The node clustering module takes the location of the ship as a node and clusters the data channels according to the distance between the node and the shore station; Nodes in the same cluster use the same data channel, and multiple data channels form a network topology; Node channel binding module, the node determines the channel number of the data channel and the control channel access time slot through clustering; A message interaction module determines the relative offset time for a node to send a HELLO message on a control channel according to the channel number and the control channel access time slot; the HELLO message includes the location of the node, the node address and the channel number used by the current data channel; In the dual-channel data transmission module, the node transmits data using the data channel; the node determines whether the current time is its own access time slot. If it is its own access time slot, it sends a HELLO message and performs backoff timing according to the relative offset time.

9. The multi-channel communication method based on narrowband fishing ad hoc network according to claim 8, characterized in that: The system adopts a dual MCU architecture, which includes a main MCU and a sub-MCU; the main MCU is used to control channel interaction and system coordination, and the sub-MCU is used for voice encoding and decoding and data channel monitoring dual-channel RF module.

10. The multi-channel communication method based on narrowband fishing ad hoc network according to claim 8, characterized in that: The data channel is accessed using the CSMA / CA protocol.

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