Novel underwater acoustic network MAC protocol method

Abstract

The invention discloses a novel underwater acoustic network MAC protocol method, and relates to the field of underwater acoustic communication. In order to solve the defect that in the prior art, in an underwater acoustic communication scene with long time delay and high dynamic load, self-adaptive joint optimization of a network state is difficult to realize, the technical scheme provided by the invention is as follows: a new underwater acoustic network MAC protocol method comprises the following steps: acquiring inter-node propagation time delay based on sound wave propagation; calculating a network state factor based on underwater channel characteristics; dynamically adjusting the size of a contention window according to the network state factor; a step of compensating and adjusting the contention window based on the silence period between the CTS frames; a step of performing backoff by using the adjusted contention window and transmitting a data frame through an acoustic signal; and updating propagation delay and communication state information according to ACK frame feedback. The method is suitable for efficient and reliable communication and channel access management in a multi-node environment in an underwater acoustic network.

Description

Technical Field

[0001] The present invention relates to the field of underwater acoustic communications, and specifically to a new underwater acoustic network MAC protocol. Background Art

[0002] The media access control (MAC) protocol plays a crucial role in underwater acoustic communication networks. It manages network nodes' access to shared channels, ensuring efficient data transmission between multiple nodes and avoiding network performance degradation caused by channel contention. Through a rational channel access mechanism, the MAC protocol can improve data throughput, optimize energy efficiency, and reduce transmission latency, thereby enhancing overall network performance. Furthermore, when handling link contention, the MAC protocol can take timely action to ensure reliable data transmission. This is particularly important for underwater acoustic communication networks, as signal propagation is affected by numerous factors in underwater environments, making reliable data transmission crucial for ensuring communication quality. Therefore, researching and optimizing MAC protocols in underwater acoustic communication networks has significant practical significance and application value for improving overall network performance and achieving efficient data transmission. Underwater acoustic communication networks play a crucial role in modern communications technology, but they face challenges such as long propagation delays and narrow bandwidth, making existing MAC protocols for terrestrial wireless communications inapplicable. The unique characteristics of underwater acoustic channels, such as signal attenuation and multipath propagation, necessitate a re-examination of existing communication protocols and the design of efficient and reliable MAC protocols tailored to the demands of underwater acoustic environments. Effective MAC protocols not only reduce latency and increase data transmission rates, but also optimize bandwidth utilization, thereby promoting the development of underwater acoustic communication networks. This research direction is of great significance to fields such as ocean exploration, environmental monitoring, and underwater communications. Therefore, developing MAC protocols specifically tailored to the characteristics of underwater acoustic channels will provide a solid foundation for the advancement of underwater acoustic communication technology, further expand its application scope, and achieve more efficient underwater information transmission.

[0003] Due to the complexity of the underwater environment, such as signal attenuation, multipath effects, and high noise interference, the effectiveness of traditional wireless communication protocols is limited. To address these challenges, researchers have improved existing multiple access control protocols and proposed various optimization methods to improve the efficiency and reliability of underwater communications. Hai-Heng Ng, Wee-Seng Soh et al., based on the MACA protocol, proposed the underwater multiple access collision avoidance protocol (MACA-U) to address the unique impact of the underwater environment. This protocol combines state transition rules, packet forwarding strategies, and backoff algorithms to effectively address collisions in underwater communications. To further improve channel utilization, researchers also proposed the multi-neighbor multi-access collision avoidance protocol (MACA-MN). Building on MACA-U, MACA-MN reduces the propagation delay of control messages by sending messages simultaneously to multiple neighboring nodes, effectively alleviating the hidden terminal problem and improving overall network performance. The slotted-FAMA protocol is an improved version of the FAMA protocol

[47] , which divides time into time slots for sending control packets (such as RTS, CTS, and ACK). Although the original intention of the Slotted-FAMA protocol is to improve channel access efficiency, in underwater acoustic communication, due to the existence of high latency, the time required for the handshake process increases significantly, resulting in a decrease in channel utilization and affecting the overall communication efficiency. Therefore, although Slotted-FAMA can provide good performance in some cases, its performance in high-latency environments is limited. In order to further optimize network performance, M-FAMA is improved on the basis of SFAMA and significantly improves network performance by introducing a slotted handshake MAC protocol. MR-FAMA introduces a multi-receiver mechanism to enhance data transmission capabilities. However, this method also brings collision risks, affecting the stability of the network. In addition, HTCC technology improves data transmission efficiency by effectively finding opportunities for chain concurrent transmission in chain network topology, but the application of these technologies often depends on specific topological structures, which limits their wide application in practical scenarios.

[0004] In summary, the existing technologies have the following defects: in underwater acoustic communication scenarios with long delays and high dynamic loads, the handshake mechanism causes the delay and idle period to expand; the contention window adjustment often only depends on the collision rate or channel busyness, ignoring real-time network status information such as the silent period; each protocol has a high dependence on topology or load conditions, making it difficult to achieve adaptive joint optimization of the network status. Summary of the Invention

[0005] To address the existing technical issues of difficulty in achieving adaptive joint optimization of network status in underwater acoustic communication scenarios with long latency and high dynamic load, the present invention provides the following technical solutions: A new underwater acoustic network MAC protocol method includes: Steps for obtaining inter-node propagation delay based on acoustic wave propagation; The step of calculating a network state factor based on underwater channel characteristics; The step of dynamically adjusting the contention window size according to the network status factor; The step of compensating and adjusting the contention window based on the silent period between CTS frames; The steps of performing backoff using the adjusted contention window and sending a data frame via an acoustic signal; The step of updating the propagation delay and communication status information according to the ACK frame feedback.

[0006] Furthermore, a specific implementation method is provided, in which the network status factor is calculated based on the recorded propagation delay, the average collision rate calculated in the current communication cycle, and the channel busy rate obtained by acoustic channel monitoring, and reflects the current network load status through weighted combination.

[0007] Furthermore, a specific implementation is provided, in which the contention window is dynamically adjusted by reducing the contention window when the network status factor is lower than a first preset threshold, and expanding the contention window when the network status factor is higher than a second preset threshold.

[0008] Furthermore, a specific implementation is provided in which the contention window compensation adjustment analyzes the silence period between consecutive CTS frames. If the deviation between the current silence period and the historical average silence period exceeds a set threshold, the current contention window is corrected within a preset range.

[0009] Furthermore, a specific implementation method is provided, in which the sending of data frames depends on the backoff count result in the current contention window and is sent in the form of sound waves when the channel is idle. The data frames contain a current timestamp for subsequent propagation delay update.

[0010] Furthermore, a specific implementation method is provided, which also includes parsing the time information carried in the ACK frame, refreshing the current propagation delay record, and synchronously updating the conflict and busy rate statistics as input for the next round of status evaluation.

[0011] A new underwater acoustic network MAC protocol device is also provided, including: A module for obtaining inter-node propagation delay based on acoustic wave propagation; A module for calculating the network state factor based on underwater channel characteristics; A module for dynamically adjusting the size of the contention window according to the network status factor; A module for compensating and adjusting the contention window based on the silent period between CTS frames; a module for performing backoff using the adjusted contention window and transmitting data frames via acoustic signals; A module that updates propagation delay and communication status information based on ACK frame feedback.

[0012] A computer storage medium is also provided for storing a computer program, and when the computer program is read by a computer, the computer executes the method.

[0013] A computer is also provided, comprising a processor and a storage medium, wherein when the processor reads a computer program stored in the storage medium, the computer executes the method.

[0014] A computer program product is also provided, which is a computer program that implements the method when the computer program is executed.

[0015] Compared with the prior art, the technical solution provided by the present invention is beneficial in that: In the frame structure, a timestamp field is added to each RTS / CTS / DATA / ACK frame and the propagation delay is recorded, so that the node can obtain the propagation delay between the source node and the destination node in real time and use the delay for network status evaluation and backoff window adjustment, thereby improving the network's sensitivity to delay changes and reducing conflicts and idle delays caused by delay estimation errors. A network status factor that comprehensively considers the maximum propagation delay, average collision rate, and channel busyness is introduced. The real-time load and congestion status of the network are reflected through a weighted linear combination, so that the adjustment of the contention window can take into account the three aspects of delay, collision, and busyness at the same time. Compared with the adjustment method based on a single indicator of collision rate or busyness, it significantly improves the adaptive ability in high dynamic load scenarios. For high / low latency network states, the logarithmic function and inverse function are used to quickly increase the contention window or reset it to the minimum value. In low latency state, the contention window is reduced to improve throughput and response speed, and in high latency state, the contention window is increased to reduce collision risk. This balances throughput and stability in different network environments, which is better than traditional fixed backoff or binary exponential backoff strategies. The propagation delay information carried in the CTS frame is used to capture the silent period between nodes, and a silent period deviation compensation factor is defined to slightly correct the contention window. When the silent period is higher than the historical average, the contention window is moderately increased, and when it is lower than the historical average, the contention window is slightly reduced, thereby quickly responding to instantaneous congestion changes, reducing unnecessary backoff waits and lowering the collision rate. By combining silent period optimization with adaptive contention window adjustment, while maintaining the stability of the original backoff algorithm, the idle delay and collision frequency are collaboratively reduced through fine-tuning the compensation mechanism, achieving a dual improvement in channel utilization and delay performance. Compared with the solutions that optimize a single parameter, more balanced network performance can be achieved in complex underwater acoustic environments. It is suitable for efficient and reliable communication and channel access management in multi-node environments in underwater acoustic networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the frame structure; Figure 2 Flowchart of the process of sending data to cluster head node; Figure 3 Flowchart of the data receiving process for the sink node. DETAILED DESCRIPTION

[0017] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail with reference to the accompanying drawings, specifically: Implementation 1: This implementation provides a new underwater acoustic network MAC protocol method, including: Steps for obtaining inter-node propagation delay based on acoustic wave propagation; The step of calculating a network state factor based on underwater channel characteristics; The step of dynamically adjusting the contention window size according to the network status factor; The step of compensating and adjusting the contention window based on the silent period between CTS frames; The steps of performing backoff using the adjusted contention window and sending a data frame via an acoustic signal; The step of updating the propagation delay and communication status information according to the ACK frame feedback.

[0018] The network status factor is calculated based on the recorded propagation delay, the average collision rate calculated in the current communication cycle, and the channel busy rate obtained by acoustic channel monitoring, and reflects the current network load status through a weighted combination.

[0019] The dynamic adjustment method of the contention window includes: reducing the contention window when the network status factor is lower than a first preset threshold, and expanding the contention window when the network status factor is higher than a second preset threshold.

[0020] The contention window compensation adjustment analyzes the silence period between consecutive CTS frames. If the deviation between the current silence period and the historical average silence period exceeds a set threshold, the current contention window is corrected within a preset range.

[0021] The transmission of data frames depends on the backoff count result within the current contention window and is sent in the form of sound waves when the channel is idle. The data frame contains the current timestamp for subsequent propagation delay update.

[0022] It also includes parsing the time information carried in the ACK frame, refreshing the current propagation delay record, and synchronously updating the conflict and busy rate statistics as input for the next round of status evaluation.

[0023] Implementation Method 2: This implementation method further describes the technical solution provided in Implementation Method 1 in detail. Specifically: Step 1: Propagation delay measurement and timestamp synchronization.

[0024] Each node adds a local timestamp when sending an RTS frame and records the arrival time when receiving a CTS frame to calculate the one-hop propagation delay.

[0025] After network startup, node A sends an RTS control frame to node B. This frame contains the local time stamp of the sending moment. Upon receiving the RTS, node B immediately writes back the time it received the RTS and the time it sent the CTS in a CTS frame. Upon receiving the CTS, node A compares the RTS sending tag with the CTS receiving tag, and the CTS sending tag with the local CTS receiving time to determine the round-trip propagation delay, halve it, and record it as the single-hop propagation delay. This delay value is stored in the local delay table for subsequent network status assessment.

[0026] Step 2: Calculate the network status factor.

[0027] The network status factor is generated based on the weighting of the maximum propagation delay, average collision rate and channel busy rate.

[0028] During the continuous RTS / CTS interaction, the node regularly counts the maximum single-hop propagation delay in the recent period, the ratio of data frame collisions to the number of attempts (collision rate), and the ratio of the channel busy time detected by the physical layer to the entire observation window time (busy rate). The three are linearly combined according to preset weights to obtain a network status factor that comprehensively reflects the delay fluctuation, collision intensity and channel occupancy. This factor is directly used as the input for the next contention window adjustment.

[0029] Step 3: Adaptive adjustment of contention window.

[0030] Dynamically increase or decrease the contention window based on network status factors and delay thresholds.

[0031] The node compares the current network status factor with the upper and lower thresholds: when both latency and congestion are at low levels, the contention window is reduced logarithmically to improve throughput; when latency or congestion is higher than the threshold, the window is rapidly increased in inverse proportion to reduce collisions; if the factor falls in the middle range, the window is maintained in a smooth transition between the minimum and maximum values; the result of this adjustment is the maximum count limit for this rollback.

[0032] Step 4: Silent period monitoring and compensation.

[0033] The contention window is slightly compensated by using the silence duration deviation between CTS frames.

[0034] The node analyzes the arrival time difference of adjacent CTS frames to obtain the silent period between the two frames. It then compares this silent period with the historical average silent value. If the current silent period is significantly higher than the average, the node slightly increases the contention window to avoid premature retries under sudden congestion. If it is lower than the average, the node slightly reduces the window to reduce unnecessary waiting. The compensation amount is fine-tuned according to a configurable proportional coefficient to ensure system stability.

[0035] Step 5: Frame sending and confirmation.

[0036] The node performs backoff counting in the adjusted contention window and sends various frames in the order of RTS→CTS→DATA→ACK, all with the latest timestamp.

[0037] After the node enters the backoff phase, it counts down according to a randomly selected count when the physical channel is idle; when the count reaches zero, it sends an RTS with the timestamp of this transmission; after receiving the CTS and updating the delay information, it immediately sends a data frame, also with the sending time attached; after receiving the data, the destination node sends back an ACK and records the receiving time in the ACK; after receiving the ACK, the sending node updates the delay and channel information and triggers the network status evaluation of the next cycle.

[0038] Step 6: Loop iteration and dynamic optimization.

[0039] Each node repeats steps one to five, continuously updating the delay table, network status factor, and contention window to achieve adaptive optimization.

[0040] During data interaction, nodes continuously execute the above-mentioned measurement, calculation, adjustment, compensation, and sending processes. Network status factors, delay records, and silent period statistics are updated using a sliding window method, and old data is eliminated according to the preset window length. The upper and lower limits of the contention window can be pre-set according to different application scenarios. The entire process is integrated into the MAC state machine to ensure that nodes can adapt in real time in highly dynamic loads and changing underwater acoustic environments, thereby achieving the dual optimization of channel access efficiency and reliability described in this solution.

[0041] Implementation Method 3: Combination Figure 1-3 This embodiment further describes the above technical solution in detail through specific examples, specifically: This implementation proposes a MAC protocol that combines silent period and contention window optimization, namely the SPCW-MAC protocol. The following sections describe the design principles, including frame structure design, network state factor calculation, adaptive contention window adjustment, silent period optimization, and a combined silent period and CW scheduling optimization mechanism.

[0042] The SPCW-MAC protocol mainly includes four data packets: RTS, CTS, DATA, and ACK. The following describes the structure of these frames. Figure 1 As shown in the figure, Type refers to the frame type and is used by the receiving node to determine the data frame type. SourceAddress refers to the address of the current sending node, and DestinationAddress refers to the address of the destination node. Payload refers to the transmitted data. TimeStamp refers to the timestamp, which records the specific time when the frame is sent. The receiving end can use this to accurately determine the propagation delay between the source node and itself, recorded as TSD, and store this value in the corresponding time field, Propagation Delay. This provides real-time basis for subsequent network status evaluation and backoff window adjustment.

[0043] The calculation of the network state factor is part of the backoff mechanism optimization. In the initial stage of the network, this implementation defines a new parameter , introducing the delay effect, combined with the average conflict rate , channel busy rate , which comprehensively reflects the real-time status of the network, is calculated as shown in the following formula: (1) in is the maximum propagation delay of the current network, Represents the actual propagation delay between current nodes, 、 、 is the weight coefficient.

[0044] In high-latency underwater wireless sensor networks, propagation delay significantly prolongs the idle period of the channel, which frequently triggers the expansion of the contention window when nodes send data synchronously, resulting in excessive occupation of channel resources and reduced overall throughput. Specifically, long delay not only increases the round-trip delay of data packets, but also increases the waiting time generated during the RTS-CTS handshake and ACK confirmation process, thereby reducing the time for effective data transmission. At the same time, each node needs to wait for a long time before confirming the success of data transmission, causing the channel to be occupied for a long time, thereby reducing the node's data transmission opportunities and reducing channel utilization, exacerbating network competition pressure. It can be seen that propagation delay plays a decisive role in underwater wireless sensor networks. It not only directly affects the total delay of the network, but also has a profound impact on throughput and channel utilization. In order to optimize network performance, it is necessary to comprehensively consider the impact of propagation delay on various indicators, and achieve effective performance balance through appropriate contention window adjustment and silent period optimization mechanisms. Therefore, It should be given greater weight.

[0045] The average collision rate mainly reflects the intensity of competition between nodes. Although the average collision rate has a significant impact on channel resource occupancy under high load conditions, this impact is mainly reflected in short-term adjustments and has a relatively small impact on long-term network performance. Therefore, under low load or short-term fluctuations, Keeping it at a low level helps prevent contention window adjustments from causing excessive interference to overall network performance. The channel busy rate is a key indicator of overall network congestion. A high channel busy rate usually indicates less network idle time. To alleviate performance degradation caused by channel congestion, properly adjusting the contention window has a positive effect, but over-adjusting it may lead to a decrease in throughput. Therefore, the parameters that affect the channel busy rate should be adjusted. Set parameters higher than those that reflect the impact of the conflict , to achieve a balance between throughput and latency.

[0046] First, calculate the average propagation delay based on the delay information from each cluster head node to the sink node in the current network. , the current network is divided into low delay state and high delay state. If the current propagation delay , take the current network as low latency state, if , consider the current network to be in a high-latency state. The low-latency and high-latency states reflect different network loads and channel usage, respectively. In the low-latency state, propagation delays are short, channel idle time is long, and network load is light. Therefore, the contention window can be appropriately reduced, thereby improving throughput and network responsiveness. In the high-latency state, due to longer propagation delays and heavier channel loads, the contention window needs to be appropriately increased to reduce collisions and retransmissions, thereby improving the stability and reliability of data transmission. Therefore, the dynamic adjustment strategy of the contention window differs significantly between the two delay states and requires precise adjustment based on the actual network load and propagation conditions.

[0047] In the low-latency state, the propagation time of data packets is short, the propagation delay of information from the source node to the sink node is low, and the channel response time is relatively fast. Due to the low propagation delay, the channel is relatively idle for a longer period of time. Nodes in the network can quickly occupy the channel and transmit data, reducing channel waiting time and the incidence of conflicts. At the same time, the low-latency state usually occurs when the network load is low, there is less competition between nodes, and the network is less congested. At this time, the communication demand in the network is low, and nodes can access the channel more efficiently. The logarithmic function can still be used to gradually increase the CW. The CW adjustment process is as follows: 1) Initial setting is CW=CW min .

[0048] 2) After a collision, use a logarithmic function to increase CW as follows: (2) in, CW i-1 It is the competition window when conflict occurs. CW i It is the competition window after adjustment.

[0049] 3) After successful transmission, reset CW to: (3) In a high-latency state, packet propagation delay increases. Due to the large propagation delay, nodes need to wait longer for data transmission and confirmation. As a result, the time interval between nodes entering the channel becomes longer, resulting in increased data transmission response time. The channel idle time is shorter. Because multiple nodes may attempt to access the channel at the same time, competition in the network becomes more intense, and nodes need to obtain a larger CW more quickly to ensure packet transmission and avoid conflicts. In this case, the reciprocal function can also be used to quickly increase the CW. The CW adjustment process is as follows: 1) The initial value is set to CW=CW min .

[0050] 2) After a collision, CW is set to: (4) 3) After successful transmission, reset CW to: (5) In both states, after each CW update, a new backoff counter is chosen as follows: (6) When the source node starts to establish communication, the actual propagation delay between the source node and the destination node is T SD To calculate Q RTS ,so Q RTS It is recorded in the RTS frame. All nodes that detect the RTS frame will Q RTS To calculate its own silent time, Q RTS The calculation is as follows: (7) When the destination node receives the RTS frame, it reads the timestamp and calculates the time based on the current reception time. T SD , then the destination node calculates the propagation delay T SD Added to CTS control package and updated Q CTS ,in, Q CTS The calculation of is shown in the formula below.

[0051] (8) After receiving the CTS control packet, the source node can obtain T SD , and on this basis calculate T DATA , then the source node will contain T DATA After the destination node receives the DATA data packet from the source node, other neighboring nodes have updated their silent time values ​​according to the data in the received RTS frame and DATA frame.

[0052] (9) Finally, the destination node returns Q ACK=0, other nodes within the transmission range clear the silent time and start to compete for the channel again.

[0053] The length of the silent period can also indirectly reflect the network's busyness under real-time load changes, and can be used to supplement the existing backoff mechanism's adjustment of the CW. However, traditional CW regulation often ignores the congestion level conveyed by this silent information. In highly dynamic load scenarios, this single criterion makes it difficult to capture instantaneous congestion differences. The combined silent period and CW scheduling optimization mechanism introduced in this embodiment maintains the original CW update rules unchanged and uses the real-time measured silent period to slightly correct the CW. When the silent period is detected to have slightly increased compared to the historical average, the CW is moderately increased to reduce the collision risk. Conversely, when the silent period is slightly shortened, the CW is slightly reduced to reduce unnecessary backoff waiting. This compensation only fine-tunes the CW, maintaining the stability of the original backoff algorithm while providing additional adaptability when the network load fluctuates. Ultimately, it reduces collisions and idle delays, playing a positive auxiliary role in improving the MAC layer performance of underwater wireless sensor networks.

[0054] Since the size and frequency of control packets are similar, and the CTS packet contains the propagation delay of the current data packet, it is convenient for other neighboring nodes to obtain the propagation delay of the current node transmission, and it can more accurately reflect the delay status of the current network. Therefore, the CTS packet is selected to capture the silence feature and define the silence control factor. , the calculation formula is as follows.

[0055] (10) in, is the average silent period of historical CTS statistics, is the CTS silent period of the current period, It refers to the average time slot duration, which is used to quantify the duration of a single time slot; Refers to the number of time slots counted within an adjustment period.

[0056] Calculate Later, if , then it is considered that the current silent period is longer than the historical average silent period, the current channel state is relatively busy, and the CW can be appropriately increased to ensure a larger backoff time between nodes and data transmission. , it is considered that the current silent period is lower than the historical average silent period, the channel idle time is relatively short, and the nodes have more opportunities to compete for the channel. The CW can be appropriately reduced to quickly transmit data, optimize the utilization of short-term idle channels, reduce delays, and improve network throughput. The compensation CW is adjusted according to the following formula: (11) in, It is the adjustment intensity coefficient, which ranges between 0 and 1 and determines the sensitivity of the adjustment amplitude. Will make the CW adjustment more drastic; smaller The adjustment of the CW value in the backoff mechanism is ultimately determined according to the following formula: (12) The protocol process is divided into two parts: the sending process of the cluster head node and the receiving process of the surface sink node. Figure 2 and Figure 3 shown.

[0057] In the process of establishing communication, this embodiment also calls the cluster head node the source node, the cluster head outside the communication process is called the neighbor node, and the surface convergence node is also called the destination node. When the cluster head node is ready to send data to the convergence node, it detects whether there are data packets waiting to be sent in the current queue. If so, it enters the backoff phase. The backoff phase calculates the network status factor, the determination of high and low delay states, and the modification of the contention window. After the backoff process is completed, the source node sends an RTS packet to the convergence node and waits for the CTS packet sent by the convergence node to the source node. When the CTS packet from the convergence node is received, the propagation delay between the current source node and the convergence node is extracted. The propagation delay is used for the node to calculate the network status factor and the determination of high and low delay in the next cycle, and then calculates the compensated CW value. The compensated CW value will be used to adjust the contention window of the node in the next cycle. Update Q DATA After the value is obtained, the DATA data packet is sent to the sink node. Finally, it waits to receive the ACK packet sent by the sink node. After receiving the ACK, this round of communication ends.

[0058] After receiving the RTS packet, the sink node establishes a communication process with the current source node by obtaining the sending address of the source node in the RTS packet, extracts the sending timestamp of the source node in the RTS, calculates the propagation delay between the source node and the sink node by recording the current receiving time, and updates Q CTS After that, wait for the source node to send DATA, and after receiving the DATA sent by the source node, update Q DATA , and finally sends ACK to the source node to end this round of communication.

[0059] The above further describes the technical solution provided by the present invention in detail through several specific embodiments in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific embodiments described above are not intended to limit the present invention. Any reasonable modification and improvement of the present invention, combination of embodiments and equivalent replacement based on the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A new underwater acoustic network MAC protocol method, characterized in that: include: Steps for obtaining inter-node propagation delay based on acoustic wave propagation; The step of calculating a network state factor based on underwater channel characteristics; The step of dynamically adjusting the contention window size according to the network status factor; The step of compensating and adjusting the contention window based on the silent period between CTS frames; The steps of performing backoff using the adjusted contention window and sending a data frame via an acoustic signal; The step of updating the propagation delay and communication status information according to the ACK frame feedback.

2. A new underwater acoustic network MAC protocol method according to claim 1, characterized in that: The network status factor is calculated based on the recorded propagation delay, the average collision rate calculated in the current communication cycle, and the channel busy rate obtained by acoustic channel monitoring, and reflects the current network load status through a weighted combination.

3. A new underwater acoustic network MAC protocol method according to claim 1, characterized in that: The dynamic adjustment method of the contention window includes: reducing the contention window when the network status factor is lower than a first preset threshold, and expanding the contention window when the network status factor is higher than a second preset threshold.

4. A new underwater acoustic network MAC protocol method according to claim 1, characterized in that: The contention window compensation adjustment analyzes the silence period between consecutive CTS frames. If the deviation between the current silence period and the historical average silence period exceeds a set threshold, the current contention window is corrected within a preset range.

5. A new underwater acoustic network MAC protocol method according to claim 1, characterized in that: The transmission of data frames depends on the backoff count result within the current contention window and is sent in the form of sound waves when the channel is idle. The data frame contains the current timestamp for subsequent propagation delay update.

6. A new underwater acoustic network MAC protocol method according to claim 1, characterized in that: It also includes parsing the time information carried in the ACK frame, refreshing the current propagation delay record, and synchronously updating the conflict and busy rate statistics as input for the next round of status evaluation.

7. A new underwater acoustic network MAC protocol device, characterized in that: include: A module for obtaining inter-node propagation delay based on acoustic wave propagation; A module for calculating the network state factor based on underwater channel characteristics; A module for dynamically adjusting the size of the contention window according to the network status factor; A module for compensating and adjusting the contention window based on the silent period between CTS frames; a module for performing backoff using the adjusted contention window and transmitting data frames via acoustic signals; A module that updates propagation delay and communication status information based on ACK frame feedback.

8. A computer storage medium for storing a computer program, characterized in that When the computer program is read by a computer, the computer executes the method according to claim 1 .

9. A computer comprising a processor and a storage medium, characterized in that When the processor reads the computer program stored in the storage medium, the computer executes the method according to claim 1 .

10. A computer program product, being a computer program, characterized in that When the computer program is executed, the method according to claim 1 is implemented.

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