Aodv routing method based on hello message statistical feature mapping luciferin

Abstract

The application relates to the technical field of mobile self-organizing network and flight ad hoc network communication, and discloses an AODV routing method based on Hello message statistical characteristic mapping luciferin. The strategy aims at the problem that the traditional AODV protocol is prone to misjudging the communication gray area as an effective link in a high dynamic network, the Hello message timestamp is extended to perceive link jitter, and multi-dimensional features such as a successful receiving rate and signal strength are combined to carry out normalization processing, so as to construct an instantaneous fitness function; a bionic glowworm swarm optimization mechanism is further introduced to dynamically update luciferin values with historical memory; finally, pruning is implemented according to the luciferin threshold value in the routing discovery stage, so that unstable links are blocked.

Description

Technical Field

[0001] This invention belongs to the field of Mobile Ad Hoc Network (MANET) and Flight Ad Hoc Network (FANET) communication technology, specifically involving a routing protocol improvement method based on the biomimetic firefly swarm optimization (GSO) principle and deeply integrating the statistical characteristics of link-layer Hello messages. This invention is particularly suitable for ad hoc network environments with high-speed movement and drastic topology changes, such as those involving drones, and aims to improve routing stability and packet delivery rate by quantifying and memorizing link quality. Background Technology

[0002] In mobile ad hoc networks, AODV (Ad hoc On-Demand Distance Vector) is a widely used on-demand routing protocol. Its core mechanism relies on periodic Hello messages for neighbor discovery and route liveness maintenance. However, traditional AODV protocols have significant flaws in their handling of Hello messages: if received within a specified time, the link is considered connected; if multiple packets are lost consecutively, the link is considered disconnected. In highly dynamic FANET environments, wireless link states are complex and changeable, frequently exhibiting intermittent "critical states" or "ghost neighbors," also known as "communication gray zones." Within the gray zone, the link is in a critically unstable state, with low packet delivery rates and severe latency jitter, but Hello messages, due to their short packet length and low transmission frequency, can still be received intermittently. Traditional AODV protocols are highly prone to mistakenly identifying "ghost neighbors" within the gray zone as valid nodes, leading to the establishment of highly unstable routes and causing frequent route interruptions and reconstructions. Furthermore, existing routing protocols incorporating GSO algorithms typically treat node remaining energy as fluorescein, which fails to reflect millisecond-level channel fading and topology shifts, and overlaps with existing energy management mechanisms in the network. Therefore, there is an urgent need for a routing evaluation method that can utilize the deep statistical characteristics of Hello messages to keenly perceive instantaneous link fluctuations and possess historical state memory capabilities, in order to filter out gray-area links and improve the stability of highly dynamic networks. Summary of the Invention

[0003] This invention proposes an AODV routing method based on Hello message statistical feature mapping. To address the aforementioned technical problems, the specific technical solution adopted by this invention is as follows: 1. Hello message jitter perception based on timestamp extension. This invention improves the Hello message of the AODV protocol by adding a 32-bit unsigned integer "SendTimestamp" field to the reserved fields. The receiving node records the actual arrival time of the message, and by calculating the rate of change of the "send-receive" time difference, the transmission jitter of the link is accurately quantified. Let the one-way transmission delay of the previous Hello message be... The time of receiving this Hello message is The message carries the sending time as The delay of this one-way transmission The instantaneous jitter of the link as defined in this invention The calculation formula is: This formula effectively offsets system scheduling jitter at the transmitting end, ensuring that the calculated jitter value only reflects the transmission quality of the wireless link, thereby more accurately identifying MAC layer retransmission fluctuations caused by communication gray areas. 2. Normalization Mapping of Multidimensional Statistical Features To eliminate differences between different units, this invention introduces Min-Max Normalization and its inverse mapping mechanism, uniformly mapping the success rate of reception (PDR), link jitter, and signal strength (RSSI) statistically obtained within the sliding window to... Dimensionless values ​​within the interval. The specific mapping formula is as follows: (1) Normalized value of reception success rate : Where N is the sliding window size and C is the number of Hello packets successfully received within the window. (2) Normalized signal strength value : ;in, The current signal strength, and These are the preset minimum and maximum saturation limits for receiving sensitivity, respectively. (3) Link jitter normalized value : ;in, This is the maximum jitter tolerance allowed by the system. This is the minimum jitter value. If > ,but =0. 3. Construction of the Instantaneous Fitness Function This invention constructs an instantaneous fitness function reflecting the quality of the link at the current time t based on normalized statistical characteristics. : ;in, , , These are the receiver rate weight, jitter weight, and signal strength weight, respectively, and they satisfy the following constraints: 4. Dynamic Update of Fluorin with Historical Memory: This invention introduces an iterative mechanism from the biomimetic firefly swarm optimization (GSO) algorithm to transform instantaneous fitness into a "fluorin value" with historical memory characteristics. The updated formula is as follows: ;in The luciferin value recorded at the previous moment; Volatility factor, range of values This is used to simulate the natural decay of luciferin; As an enhancement factor, the range of values ​​is... This is used to control the degree of influence of the current observation on the state update. 5. Threshold pruning decision during the route discovery phase: In the AODV route discovery process, soft constraint logic is implemented when processing Route Request (RREQ) messages. When a node receives an RREQ message from neighbor K, it reads the current fluorite value of that neighbor from the neighbor table. and the preset gray area blocking threshold Comparison: If If the link is determined to be in a communication gray zone, the node will directly discard the RREQ message and will not forward it. Determine the link health, update the routing table according to standard procedures, and forward the RREQ. Attached Figure Description

[0004] Figure 1 This is a schematic diagram of the improved Hello message structure and timestamp processing logic in an embodiment of the present invention. Figure 2 This is a flowchart of instantaneous fitness calculation and fluorescein update in an embodiment of the present invention. Figure 3 This is a schematic diagram of a routing pruning strategy based on fluorescein threshold in an embodiment of the present invention. Detailed Implementation

[0005] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation steps. This embodiment, based on a network simulation environment, improves the standard AODV protocol and implements a routing method based on Hello message statistical feature mapping of phosphors. The specific execution flow of this embodiment mainly includes the following steps: Step 1) Improve the Hello message structure and neighbor table design as shown in the attached figure. Figure 1 As shown, a 32-bit unsigned integer field SendTimestamp (used for sending timestamps) is added to the reserved fields of the standard AODV Hello message. Simultaneously, the statistical structure in the node's neighbor list is expanded to include: WindowBuffer[]: a sliding window of length N, used to record the Hello reception status and corresponding signal strength for the most recent N periods. LastTransit: records the transmission time of the last received packet, used to calculate jitter. Luciferin: stores the current luciferin value of the neighbor, initially set to maximum brightness. Step 2) Perform precise jitter calculation based on timestamps. When the node is at time... Received a Hello message from a neighbor (the message includes the sending time) When calculating the current one-way transmission delay sample, first calculate the current one-way transmission delay sample. To eliminate the effects of clock asynchrony, this invention employs the relative difference method to calculate link jitter. : ;in This represents the previous transmission delay sample recorded in the neighbor table. This formula reflects the variation in transmission delay between two adjacent Hello packets. If... A large value indicates that the link is extremely unstable or there is severe congestion. Update the neighbor table. Store in LastTransit. Step 3) Normalization of statistical features: Based on the statistical data within the sliding window, the node normalizes the three key indicators, mapping all indicators to... The interval, where 1 represents the best state and 0 represents the worst state: 1. Normalized Success Rate (PDR): Given C successful Hello packets received within a statistical window, and N as the window size, the normalized PDR value is: 2. Signal Strength Index (RSSI) Normalization (Forward Mapping): Sets the minimum receiver sensitivity. and saturation upper limit Read the signal strength of the current frame. Max-min normalization is used: If the calculation result exceeds the boundary, it is truncated to [0, 1]. 3. Link jitter normalization (reverse mapping): Since smaller jitter values ​​are better, reverse mapping is required. Set the maximum allowable jitter tolerance of the system. and minimum jitter Normalized value: ;like > ,but =0. This formula ensures that low jitter corresponds to a high score. Step 4) Construct the instantaneous fitness function based on the normalized values ​​obtained in step 3, as shown in the appendix. Figure 2 As shown, the weighted summation method is used to calculate the instantaneous fitness of a node for its neighbor at the current time t. : ;in, , , These are the receiver rate weight, jitter weight, and signal strength weight, respectively, and they satisfy the following constraints: Step 5) Perform GSO fluorite iterative update. Utilizing the core mechanism of the GSO algorithm, the instantaneous fitness is transformed into a fluorite value with historical memory. The updated formula is as follows: ;in, This is the fluorescein value recorded at the previous moment. Volatile factors ( This is used to simulate the natural decay of luciferin. When a neighbor is in a gray area, causing Hello packets to be lost (at this time...) When the luciferin value approaches 0, the luciferin value will be... The rate drops exponentially, thus quickly reflecting link deterioration. For enhancing factor ( This is used to control the degree to which the current observation affects the state update. Step 6) Threshold pruning in route discovery is shown in the appendix. Figure 3 As shown, a decision module is embedded in the logic of the AODV routing protocol in handling route request (RREQ) messages. When a node receives an RREQ message from neighbor K, it performs the following operations: 1. Retrieve the neighbor table to obtain the current fluorescence value of neighbor K. 2. With the preset gray area blocking threshold Compare. 3. Decision logic: If The node determines that the link is in a communication gray zone, belonging to an unreliable connection. The node discards the RREQ message and does not forward it, preventing the establishment of a route through this weak link. Determine link health, update routing table according to standard AODV procedure, and forward RREQ.

Claims

1. An AODV routing method based on Hello message statistical feature mapping fluorite, characterized in that, Includes the following steps: Step 1) Improve the Hello message structure and neighbor table design: Add a sending timestamp field to the reserved field of the Hello message in the AODV protocol, and establish a sliding window in the node's neighbor list to record the statistical characteristics of Hello messages; Step 2) Perform timestamp-based precise jitter sensing: The receiving node records the actual arrival time of the Hello message and, combined with the sending timestamp in the message, calculates the instantaneous transmission jitter of the link; Step 3) Normalization mapping of multidimensional statistical features: Introduce the maximum-minimum normalization mechanism to uniformly map the reception success rate, link jitter and signal strength statistically obtained within the sliding window into dimensionless values; Step 4) Constructing the instantaneous fitness function: Based on the normalized statistical characteristics, an instantaneous fitness function reflecting the quality of the link at the current moment is constructed by weighted summation; Step 5) Dynamic update of luciferin with historical memory: Introduce the iterative mechanism of the biomimetic firefly swarm optimization (GSO) algorithm, and use the volatile factor and the enhancement factor to convert the transient fitness into luciferin value with historical memory characteristics. Step 6) Threshold pruning decision during the route discovery phase: During the AODV route discovery process, based on the comparison between the fluorite value of the neighboring node and the preset gray zone blocking threshold, it is decided whether to forward the route request (RREQ) message.

2. The AODV routing method based on Hello message statistical feature mapping of fluorite as described in claim 1, characterized in that, In step 2, the instantaneous transmission jitter of the link The calculation formula is: ； in, This indicates the one-way transmission delay of this Hello message. This is the moment the Hello message is received. The sending time carried in the message; The one-way transmission delay of the previous Hello message is used to offset the system scheduling jitter at the sending end through this relative difference method.

3. The AODV routing method based on Hello message statistical feature mapping of fluorite as described in claim 1, characterized in that, In step 3, the specific formula for the normalization mapping is as follows: Normalized value of reception success rate for: ； Where N is the size of the sliding window, and C is the number of Hello packets successfully received within the window; Signal strength normalized value for: ； in, The current signal strength, and These are the preset minimum and maximum saturation limits for receiving sensitivity, respectively; if the calculation result exceeds the boundary, it is truncated to [0,1]. Link jitter normalized value for: ； in, This is the maximum jitter tolerance allowed by the system. This is the minimum jitter value. If > ,but =0.

4. The AODV routing method based on Hello message statistical feature mapping of fluorite as described in claim 1, characterized in that, In step 4, the instantaneous fitness function The specific form is: ； in, , , These are the normalized reception success rate, link jitter, and signal strength, respectively. , , These are the corresponding weight coefficients, and they satisfy the following constraints: 。 5. The AODV routing method based on Hello message statistical feature mapping of fluorite as described in claim 1, characterized in that, In step 5, the fluorite value The update formula is: ； in The luciferin value recorded at the previous moment; Volatility factor, range of values This is used to simulate the natural decay of luciferin; As an enhancement factor, the range of values ​​is... This is used to control the degree to which the current observation affects the state update.

6. The AODV routing method based on Hello message statistical feature mapping of fluorite as described in claim 1, characterized in that, In step 6, the specific logic of the threshold pruning decision is as follows: When a node receives a routing request (RREQ) message from neighbor K, it reads the current fluorite value of that neighbor from the neighbor table. ; Will With the preset gray area blocking threshold Comparison: If If the link is determined to be in a communication gray zone, the node will directly discard the RREQ message and will not forward it. Determine the link health, update the routing table according to standard procedures, and forward the RREQ.

Images