Dynamic ad hoc network method and system for interphone

Abstract

The invention relates to the technical field of wireless networking, in particular to a dynamic ad hoc network method and system for an interphone, and the method comprises the steps: obtaining the length of a next window of each window of each node in a process of adjusting the transmission rate of each node through an RRAA algorithm for a pre-established interphone network; recording the time interval of two adjacent times of spread spectrum factor adjustment of each node as a spread spectrum factor stable interval, and evaluating whether to adjust the spread spectrum factor of each network by comparing the frame error rate of each node in each window with the MTL and ORI values in the spread spectrum factor stable interval where each window is located; the spreading factor of each node is adjusted; in the route discovery process in the AODV protocol, updating the RREQ received by each node; evaluating whether a non-first RREQ received by each node is discarded or not; and carrying out routing selection of the interphone according to the AODV protocol. The invention aims to improve the throughput and communication performance of the interphone network.

Description

Technical Field

[0001] The present application relates to the field of wireless networking technology, and in particular to a dynamic self-organizing networking method and system for walkie-talkies. Background Art

[0002] Digital walkie-talkies are the most widely used mobile terminals in dedicated mobile communications. During large-scale events, staff frequently use digital walkie-talkies for voice communication. Using wireless ad hoc networking technology, establishing a communication network between multiple digital walkie-talkies not only increases the communication range of walkie-talkies but also enables voice communication between two walkie-talkies even when channels are blocked. In low-power wide-area networks (LPWANs), LoRa (Long Range), a next-generation communication technology operating in unlicensed frequency bands, meets the needs of dedicated mobile communication networks due to its low power consumption, low cost, long range, and low complexity.

[0003] LoRa technology uses Chirp modulation to achieve spread-spectrum communication, improving its anti-interference capabilities. However, compared to other spread-spectrum methods, the performance of LoRa technology's Chirp modulation depends on the size of the LoRa technology's spreading factor (SF). During large-scale events, the communication environment of staff members' digital walkie-talkie wireless ad hoc networks fluctuates significantly. A fixed spreading factor (SF) cannot adapt to the complex variations in the wireless channels between walkie-talkies, thus hindering the communication performance of the digital walkie-talkie ad hoc networks. Furthermore, during the route discovery process of the Ad-hoc On-Demand Distance Vector (AODV) protocol, intermediate nodes only forward the first received RREQ (Route Request), and the destination node only responds to the first received RREQ. This ignores the fact that in a LoRa ad hoc network, there are typically multiple available routes for sending data from the source node to the destination node. This results in reduced throughput of the walkie-talkie network, further impacting the communication performance of the wireless ad hoc network. Summary of the Invention

[0004] In view of the above, it is necessary to provide a dynamic ad hoc networking method and system for walkie-talkies, which can improve the throughput and communication performance of walkie-talkie networks compared to traditional dynamic ad hoc networking methods for walkie-talkies:

[0005] In a first aspect, an embodiment of the present application provides a dynamic ad hoc networking method for walkie-talkies, the method comprising the following steps:

[0006] In the process of adjusting the transmission rate of each node by the RRAA algorithm for the pre-organized intercom network, the length of the next window of each window of each node is obtained by the frame error rate of each node in each window and the length of each window in the intercom network, combined with the change of the frame error rate of each node in each window and a preset number of windows before each window, wherein the initial length of the window is a preset value.

[0007] The time interval of the adjacent two times of adjusting the spreading factor of each node is recorded as the spreading factor stable interval of each node, the values of the parameters MTL and ORI of the RRAA algorithm in each spreading factor stable interval of each node are calculated respectively, whether to adjust the spreading factor of each network is evaluated by comparing the frame error rate of each node in each window with the values of MTL and ORI in the spreading factor stable interval of each window; if adjustment is needed, the spreading factor of each node is adjusted by the difference between the frame error rate in the last window before each adjustment and the values of MTL and ORI in the spreading factor stable interval of the last window, wherein the initial value of the spreading factor is a preset value.

[0008] In the route discovery process of the AODV protocol, the RREQ received by each node is updated by the data packet transmission delay under the spreading factor of the previous hop node of each node; if the number of RREQs of the same node received by each node is greater than 1, whether to discard the non-first RREQ received by each node is evaluated by comparing the path hop count and the updated transmission delay between different RREQs of the same node received by each node, which is used to optimize the route discovery process of AODV.

[0009] The intercom is routed according to the AODV protocol.

[0010] In one embodiment, the process of obtaining the length of the next window of each window of each node is:

[0011] The product of the frame error rate of each node in each window and the length of each window is calculated.

[0012] The frame error rates of each window of each node and a preset number of windows before each window are arranged in time sequence to form a frame error rate sequence of each window of each node, the average value of all elements in the first-order difference sequence of each frame error rate sequence is calculated, the maximum value of the average values calculated by all nodes is counted, the ratio of the average value corresponding to each window of each node to the maximum value is calculated, and the product value of the product and the ratio is calculated.

[0013] The length of the next window of each window of each node can be further obtained by the length of each window of each node and the product value.

[0014] In one embodiment, the length of the next window of each window of each node is the sum of the length of each window of each node and the product value rounded up.

[0015] In one embodiment, the method for evaluating whether to adjust the spreading factor of each network is:

[0016] If the frame error rate of any node in each window is simultaneously greater than the MTL and ORI values ​​within the stable interval of the spreading factor of each window, or if the frame error rate of any node in each window is simultaneously less than a preset ratio of the MTL value and a preset ratio of the ORI value within the stable interval of the spreading factor of each window, the spreading factor of the any node is adjusted; otherwise, no adjustment is made.

[0017] In one embodiment, the process of adjusting the spreading factor of each node is:

[0018] The difference between the frame error rate in the last window of each node before each adjustment and the MTL and ORI values ​​in the stable range of the spreading factor in the last window is recorded as the first difference and the second difference; the cumulative value of the first difference and the second difference is calculated;

[0019] The spreading factor of each node after each adjustment is obtained by using the spreading factor of each node before each adjustment and the accumulated value.

[0020] In one embodiment, the method for calculating the spreading factor of each node after each adjustment is:

[0021] The cumulative sum of the cumulative value and 1 is calculated; and the product of the cumulative sum and the spreading factor of each node before each adjustment is rounded off to an integer as the spreading factor of each node after each adjustment.

[0022] In one embodiment, the method for updating the RREQ received by each node is:

[0023] Add the path transmission delay field T in RREQ path , T path Updated by the node that receives and forwards RREQ. When each node receives RREQ, it obtains the spreading factor of the previous hop node and calculates the data packet transmission delay T under the spreading factor of the previous hop node. packet ; When updating RREQ, replace T in RREQ path Add T packet .

[0024] In one embodiment, the process of evaluating whether to discard non-first RREQ received by each node is as follows:

[0025] If the path hop count in the new RREQ is greater than the path hop count in the previous RREQ, the new RREQ is discarded; otherwise, each node path and T in the previous RREQ path After the update, the updated T in the new RREQ path Less than the updated T in the previous RREQ path , then forward the new RREQ, otherwise, discard the new RREQ.

[0026] In one embodiment, the optimized process of the AODV route discovery process is:

[0027] (1) The source node broadcasts RREQ;

[0028] (2) Each intermediate node receives the RREQ and obtains the spreading factor of the previous hop node of each intermediate node, which is used as the spreading factor for the previous hop node to communicate with each intermediate node. The data packet transmission delay T is calculated under the spreading factor of the previous hop node of each intermediate node. packet ;

[0029] (3) Determine whether each intermediate node has received the RREQ from the same node. If not, execute step (4); if so, execute step (5);

[0030] (4) Extract the path hop count field hops and path transmission delay field T in RREQ path , with T path =T path +T packet Update RREQ with hops=hops+1, and record hops and T locally path , determine whether the preset conditions for returning RREP are met. If they are met, unicast return RREP is performed; if not, broadcast forward RREQ;

[0031] (5) Extract the hops in RREQ. If the hops is less than or equal to the local record, update the RREQ and local record. If the T in the updated local record is path Less than T in the local record before the update path , then determine whether the preset conditions for returning RREP are met. If they are met, unicast return RREP is performed; if not, RREQ is broadcast and forwarded.

[0032] In a second aspect, an embodiment of the present application also provides a dynamic self-organizing network system for walkie-talkies, comprising a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-mentioned dynamic self-organizing network methods for walkie-talkies.

[0033] This application has at least the following beneficial effects:

[0034] By dynamically adjusting the window length, this application can more accurately reflect changes in channel quality, avoiding inaccurate frame error rate statistics or long RRAA algorithm response times caused by an overly large or small window, thereby ensuring the real-time and accuracy of channel assessment. By comparing the frame error rate with the parameters in the RRAA algorithm, the spreading factor can be adjusted in a timely manner when the channel quality changes. By dynamically adjusting the spreading factor, it can better adapt to changes in the channel environment and improve communication performance.

[0035] Furthermore, by updating the path transmission delay field in RREQ, the transmission delay of the path can be reflected more accurately, thereby selecting the path with the lowest delay, reducing the end-to-end delay and channel occupancy time of data transmission, and improving the accuracy and efficiency of route selection; by evaluating whether to discard non-first RREQs received by each node, the problem of excessive delay in the routing path caused by directly discarding RREQ can be avoided, thereby improving the accuracy and efficiency of route selection, thereby improving the throughput and communication performance of the walkie-talkie network. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] Figure 1 A flowchart of a method for dynamic ad hoc networking of walkie-talkies provided in one embodiment of the present application;

[0038] Figure 2 Schematic diagram of the window length adjustment process;

[0039] Figure 3 Schematic diagram of the optimized AODV route discovery process. DETAILED DESCRIPTION

[0040] In the description of the embodiments of this application, words such as "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "or," and "for example" is intended to present the relevant concepts in a concrete manner.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application relates. The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. It should be understood that, unless otherwise indicated, " / " represents or.

[0042] It should also be noted that the terms "first" and "second" in this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0043] The following describes in detail a specific scheme of a dynamic self-organizing network method and system for walkie-talkies provided by the present application with reference to the accompanying drawings.

[0044] See also Figure 1 , which shows a flowchart of a dynamic ad hoc networking method for walkie-talkies provided by an embodiment of the present application, the method comprising the following steps:

[0045] Step 1: Build a walkie-talkie network.

[0046] This embodiment uses wireless ad hoc networking technology to build a walkie-talkie network based on multiple digital walkie-talkies, meeting the needs of efficient voice communication between staff during large-scale events. The walkie-talkie network consists of multiple digital walkie-talkies, each acting as an independent node, and interconnected through LoRa technology. Furthermore, digital walkie-talkies can not only communicate directly but also indirectly forward messages through other walkie-talkies, thereby expanding communication coverage and solving signal obstruction issues.

[0047] The intercom network in this embodiment adopts a distributed architecture, where all nodes are equal, enabling communication without relying on a central base station. Each node has transmit, receive, and relay functions, supporting single-hop or multi-hop data transmission. Specifically, if the direct connection between two intercoms is blocked by an obstacle, the intercom network automatically selects a circuitous path through other intercoms to complete communication.

[0048] Step 2: While adjusting the transmission rate of each node using the RRAA algorithm, obtain the length of the next window of each window for each node; record the time interval between two consecutive spreading factor adjustments of each node as the spreading factor stability interval of each node; evaluate whether to adjust the spreading factor of each network by comparing the frame error rate of each node in each window with the MTL and ORI values ​​within the spreading factor stability interval of each window; and adjust the spreading factor of each node.

[0049] In the intercom network, there is a certain relationship between the transmission rate of the node and the signal strength. Because the distance between the sending node and the nodes in the coverage range is different, the channel attenuation of the signal from the sending node to each node causes the signal strength at each node to be different. If the signal is too weak and the transmission rate is too high, it cannot be received, and if the signal is relatively strong and the transmission rate is too low, it causes waste of communication resources. Considering the complexity of the wireless communication environment in large-scale activity sites, a single transmission rate cannot meet the communication needs between all digital intercom nodes, so the transmission rate between nodes needs to be dynamically adjusted according to the actual situation.

[0050] In the LoRa technology, the transmission rate between nodes is related to the spreading factor SF. Specifically, the size of the spreading factor directly affects the transmission rate. The larger the spreading factor, the lower the transmission rate; on the contrary, the smaller the spreading factor, the higher the transmission rate. In this embodiment, when the channel state between nodes changes, the spreading factor SF of the sending node is changed, and then the transmission rate is changed, thereby improving the communication performance of the intercom network. Specifically, the sending node considers the channel state of each path before sending a data frame, respectively calculates and obtains the spreading factor SF when communicating through different paths, so as to meet the different communication needs of all nodes in the intercom network, and realizes the self-adaptation of the transmission rate. The RRAA (Robust Rate Adaptation Algorithm) algorithm is an open-loop rate adaptation algorithm. By comparing the frame error rate in a period of time with the parameters MTL (Maximum Tolerable Threshold) and ORI (Opportunistic Rate Increase Threshold) in the RRAA algorithm, the change of the transmission rate is determined, so the size of the window for statistical frame error rate directly affects the performance of the RRAA algorithm. On the one hand, too small window will lead to inaccurate statistical frame error rate; on the other hand, too large window will cause the reaction time of the RRAA algorithm to increase, and the state of the channel cannot be reflected in real time.

[0051] Step 2.1, by the frame error rate of each node in each window in the intercom network and the length of each window, combined with the change of the frame error rate of each node in each window and a preset number of windows before each window, the length of the next window of each window of each node is obtained.

[0052] Based on the above analysis, the initial length of each node window is preset, the frame error rate of each node in each window and a preset number of windows before each window is arranged in time sequence to form a frame error rate sequence of each window of each node, so as to reflect the change of the channel quality.

[0053] In this embodiment, the initial length of the window is 20 frames. On the basis of satisfying the maximum window length of 40 frames and the minimum window length of 5 frames, the implementer can set the value of the initial length of the window according to actual conditions.

[0054] In this embodiment, the preset number is set to 20. The preset number is manually preset and can be set by the implementer according to actual conditions. This application does not impose any special restrictions. When the number of windows before each window is insufficient, the mean filling method is used to fill the missing data. The mean filling method is a well-known technology and will not be described in detail in this application. The implementer can also use other feasible data filling methods to fill the missing data, such as the median filling method.

[0055] Considering that the movement of people during large-scale events is the main cause of channel environment changes, and that personnel movement is often regional, this can cause significant differences in channel environment changes between different nodes in the walkie-talkie network. To prevent the RRAA algorithm window from growing too large due to drastic changes in the walkie-talkie network channel environment, the quality changes of all channels in the walkie-talkie network are compared, and the window length and window length growth rate are limited to ensure that the window frame error rate can promptly reflect changes in channel quality.

[0056] Based on the above analysis, the length of the next window of each node is obtained through the frame error rate of each node in each window and the length of each window, as well as the change of the frame error rate in the frame error rate sequence of each window of each node. The expression is:

[0057] Where W j,i 、W j,i+1 Respectively represent the length of the i-th and i+1-th windows of the j-th node; ceil() represents the upward rounding function; ΔW j,i μ represents the change in the window length of the i-th window of the j-th node, specifically the product of the frame error rate of the j-th node in the i-th window and the i-th window length; j,i represents the mean of all elements in the first-order difference sequence of the frame error rate sequence of the i-th window of the j-th node; calculate the mean of all elements in the first-order difference sequence of the frame error rate sequence of each window of each node, μ max It represents the maximum value among the average values ​​calculated by all nodes in the intercom network, and is used to limit the window length and the growth rate of the window length, realize dynamic selection of the window, and ensure the real-time performance of the channel assessment. Figure 2 shown.

[0058] In step 2.2, the time interval between two consecutive spreading factor adjustments of each node is recorded as the spreading factor stability interval of each node. The values ​​of the RRAA algorithm parameters MTL and ORI within each spreading factor stability interval of each node are calculated respectively. By comparing the frame error rate of each node in each window with the MTL and ORI values ​​within the spreading factor stability interval of each window, it is evaluated whether to adjust the spreading factor of each network. If adjustment is necessary, the spreading factor of each node is adjusted during each adjustment based on the difference between the frame error rate in the last window before each adjustment and the MTL and ORI values ​​within the spreading factor stability interval of the last window.

[0059] Furthermore, the RRAA algorithm decides whether to adjust the spreading factor based on the frame error rate of each node in each window. The time interval between two consecutive adjustments of the spreading factor of each node is recorded as the spreading factor stability interval of each node. The values ​​of MTL and ORI in each spreading factor stability interval of each node are calculated. If the frame error rate of any node in each window is simultaneously greater than the values ​​of MTL and ORI in the spreading factor stability interval of each window, the spreading factor SF of any node as a sending node is increased; if the frame error rate of any node in each window is simultaneously less than 0.5 times the MTL value and 0.5 times the ORI value in the spreading factor stability interval of each window, the spreading factor SF of any node as a sending node is reduced; in other cases, the spreading factor SF of any node remains unchanged. Among them, the calculation method of MTL and ORI is a well-known technology and will not be repeated in this application; 0.5 is only an embodiment of the present application. On the basis of satisfying the value greater than 0 and less than 1, the implementer can set its specific value according to the actual situation.

[0060] Furthermore, when the spreading factor needs to be adjusted, for each adjustment, the spreading factor of each node after each adjustment is obtained by using the spreading factor before each adjustment and the difference between the frame error rate in the last window before each adjustment and the MTL and ORI values ​​in the spreading factor stable range of the last window. The expression is:

[0061] SF′ j,n =round[SF j,n ×(1+ΔMTL n +ΔORI n )]; where SF j,n , SF′ j,n Respectively represent the spreading factors before and after the nth adjustment of the jth node; round[] represents the rounding function; ΔMTL n , ΔORI nIt represents the difference between the frame error rate in the last window before the nth adjustment of the jth node and the MTL and ORI values ​​in the stable range of the spreading factor in the last window.

[0062] In this embodiment, the initial value of the spreading factor is 9. The initial value of the spreading factor is preset manually. On the basis of satisfying that the initial value of the spreading factor is an integer in the interval [6, 12], the implementer can set the specific value of the initial value of the spreading factor according to actual conditions.

[0063] Step 3: During the route discovery process in the AODV protocol, the RREQ received by each node is updated by the data packet transmission delay under the spreading factor of the previous hop node of each node; if the number of RREQs received by each node from the same node is greater than 1, by comparing the number of path hops between different RREQs of the same node received by each node and the updated transmission delay, it is evaluated whether to discard the non-first RREQ received by each node, which is used to optimize the AODV route discovery process; the walkie-talkie route selection is performed according to the AODV protocol.

[0064] This embodiment implements walkie-talkie routing selection based on the AODV protocol, and optimizes the route discovery process in the AODV protocol according to the adaptive changes in the transmission rate in the LoRa self-organizing network, dynamically adjusts the routing strategy of the walkie-talkie network, selects the routing path with the lowest latency, reduces the end-to-end latency and channel occupancy time of data transmission, thereby improving the throughput of the walkie-talkie network and improving the communication performance of the dynamic self-organizing network of walkie-talkies.

[0065] Add the path transmission delay field T in the route request RREQ (Route Request) path , T path Updated by the node that receives and forwards RREQ, the updated T of each node path The size of is the transmission delay from the sending node to each node.

[0066] When each node receives the RREQ, it obtains the spreading factor of the previous hop node and uses it as the spreading factor for the previous hop node to communicate with each node. At the same time, it calculates the data packet transmission delay T under the spreading factor of the previous hop node. packet If you need to forward RREQ, then when updating RREQ, replace T in RREQ with path Add T packet , to achieve T path At the same time, when each node receives the RREQ from the same node again, it first determines whether the path hop count in the new RREQ is greater than the previous RREQ. If it is greater, the new RREQ is discarded; otherwise, the T in the new RREQ is compared. path Compared with T in the previous RREQ path , if each node has T in the new RREQpath and T in previous RREQ path after updating, updated T in new RREQ path updated T in new RREQ is less than updated T in previous RREQ path then forward new RREQ, otherwise, discard new RREQ, avoiding the problem of long delay of routing path caused by AODV protocol directly discarding RREQ.

[0067] Specifically, the routing discovery process of the optimized AODV is as follows:

[0068] (1) the source node broadcasts RREQ;

[0069] (2) each intermediate node receives RREQ, obtains the spreading factor size of the previous hop node of each intermediate node, and uses it as the spreading factor of the communication between the previous hop node and each intermediate node, and calculates the data packet transmission delay T packet of the previous hop node of each intermediate node under the spreading factor of the previous hop node of each intermediate node;

[0070] (3) it is judged whether each intermediate node has received RREQ of the same node, if not, step (4) is executed, if yes, step (5) is executed;

[0071] (4) hops and T path in RREQ are extracted, RREQ is updated with T path =T path +T packet and hops=hops+1, and hops and T path are recorded locally, it is judged whether the preset condition of returning RREP is met, if yes, RREP is returned by unicast, if not, RREQ is broadcasted and forwarded;

[0072] (5) hops in RREQ is extracted, if hops is less than or equal to the local record, RREQ and the local record are updated, if T path in the updated local record is less than T path in the local record before updating, it is judged whether the preset condition of returning RREP is met, if yes, RREP is returned by unicast, if not, RREQ is broadcasted and forwarded. The routing discovery process of the optimized AODV is shown in Figure 3 .

[0073] If the address of the intermediate node is consistent with the address of the requested destination in RREQ, or the intermediate node has routing information to the target node, it is determined that the condition of returning RREP is met.

[0074] Furthermore, the routing selection of the intercom is implemented according to the AODV protocol. The specific process of implementing the routing selection of the intercom according to the AODV protocol is a well-known technology and will not be described in detail in this application.

[0075] Based on the same inventive concept as the above method, an embodiment of the present application also provides a dynamic self-organizing network system for walkie-talkies, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-mentioned dynamic self-organizing network methods for walkie-talkies.

[0076] In summary, the present application can more accurately reflect changes in channel quality by dynamically adjusting the window length, avoiding problems such as inaccurate frame error rate statistics or long RRAA algorithm response time caused by an overly large or small window, thereby ensuring the real-time and accuracy of channel assessment. By comparing the frame error rate with the parameters in the RRAA algorithm, the spreading factor can be adjusted in a timely manner when the channel quality changes. By dynamically adjusting the spreading factor, it can better adapt to changes in the channel environment and improve communication performance.

[0077] Furthermore, by updating the path transmission delay field in RREQ, the transmission delay of the path can be reflected more accurately, thereby selecting the path with the lowest delay, reducing the end-to-end delay and channel occupancy time of data transmission, and improving the accuracy and efficiency of route selection; by evaluating whether to discard non-first RREQs received by each node, the problem of excessive delay in the routing path caused by directly discarding RREQ can be avoided, thereby improving the accuracy and efficiency of route selection, thereby improving the throughput and communication performance of the walkie-talkie network.

[0078] The flowcharts and block diagrams in the accompanying drawings show the possible implementation architectures, functions and operations of the systems, methods and computer program products according to the embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment or part of the code, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical functions. In some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in an order different from that disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or action, or may be implemented by a combination of dedicated hardware and computer instructions.

[0079] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the basic characteristics of the present application. Therefore, from all perspectives, the above embodiments of the present application should be regarded as exemplary and non-restrictive.

Claims

1. A dynamic ad hoc networking method for walkie-talkies, characterized in that: The method comprises the following steps: For a pre-established walkie-talkie network, when adjusting the transmission rate of each node using the RRAA algorithm, the length of the next window of each node is obtained by combining the frame error rate and the length of each window of each node in the walkie-talkie network with the change in the frame error rate of each node in each window and the preset number of windows before it. The initial window length is a preset value. The time interval between two consecutive adjustments to the spreading factor of each node is recorded as the spreading factor stability interval of each node. The values ​​of the RRAA algorithm parameters MTL and ORI within each spreading factor stability interval of each node are calculated respectively. By comparing the frame error rate of each node in each window with the MTL and ORI values ​​within the spreading factor stability interval of each window, it is evaluated whether the spreading factor of each network should be adjusted. If adjustment is required, the spreading factor of each node is adjusted during each adjustment based on the difference between the frame error rate in the last window before each adjustment and the MTL and ORI values ​​within the spreading factor stability interval of the last window. The initial value of the spreading factor is a preset value. In the route discovery process of the AODV protocol, the RREQ received by each node is updated by the data packet transmission delay under the spreading factor of each node's previous hop node. If the number of RREQs received by each node from the same node is greater than 1, the number of path hops between different RREQs received by each node from the same node and the updated transmission delay are compared to evaluate whether to discard non-first RREQs received by each node, which is used to optimize the AODV route discovery process. The intercom routing is selected according to the AODV protocol.

2. A dynamic ad hoc networking method for walkie-talkies according to claim 1, characterized in that: The process of obtaining the length of the next window of each window of each node is as follows: Calculate the product of the frame error rate of each node in each window and the length of each window; Arranging the frame error rates of each window of each node and a preset number of windows before it in time sequence to form a frame error rate sequence of each window of each node, calculating the average value of all elements in the first-order difference sequence of each frame error rate sequence; counting the maximum value of the average values ​​calculated by all nodes; calculating the ratio of the average value to the maximum value corresponding to each window of each node; and calculating the product of the product and the ratio; The length of the next window of each window of each node can be further obtained by multiplying the length of each window of each node by the product value.

3. A dynamic ad hoc networking method for walkie-talkies as claimed in claim 2, characterized in that: The length of the next window of each window of each node is the sum of the length of each window of each node and the product value rounded up.

4. A dynamic ad hoc networking method for walkie-talkies according to claim 1, characterized in that: The method for evaluating whether to adjust the spreading factor of each network is: If the frame error rate of any node in each window is simultaneously greater than the MTL and ORI values ​​within the stable interval of the spreading factor of each window, or if the frame error rate of any node in each window is simultaneously less than a preset ratio of the MTL value and a preset ratio of the ORI value within the stable interval of the spreading factor of each window, the spreading factor of the any node is adjusted; otherwise, no adjustment is made.

5. A dynamic ad hoc networking method for walkie-talkies according to claim 1, characterized in that: The process of adjusting the spreading factor of each node is as follows: The difference between the frame error rate in the last window of each node before each adjustment and the MTL and ORI values ​​in the stable range of the spreading factor in the last window is recorded as the first difference and the second difference respectively; Calculating a cumulative value of the first difference and the second difference; The spreading factor of each node after each adjustment is obtained by using the spreading factor of each node before each adjustment and the accumulated value.

6. A dynamic ad hoc networking method for walkie-talkies as claimed in claim 5, characterized in that: The calculation method of the spreading factor of each node after each adjustment is as follows: The cumulative sum of the cumulative value and 1 is calculated; and the product of the cumulative sum and the spreading factor of each node before each adjustment is rounded off to an integer as the spreading factor of each node after each adjustment.

7. A dynamic ad hoc networking method for walkie-talkies as claimed in claim 1, characterized in that: The method for updating the RREQ received by each node is: Add the path transmission delay field T in RREQ path , T path Updated by the node that receives and forwards RREQ. When each node receives RREQ, it obtains the spreading factor of the previous hop node and calculates the data packet transmission delay T under the spreading factor of the previous hop node. packet ; When updating RREQ, replace T in RREQ path Add T packet .

8. A dynamic ad hoc networking method for walkie-talkies as claimed in claim 7, characterized in that: The process of evaluating whether to discard the non-first RREQ received by each node is as follows: If the path hop count in the new RREQ is greater than the path hop count in the previous RREQ, the new RREQ is discarded; otherwise, each node path and T in the previous RREQ path After the update, the updated T in the new RREQ path Less than the updated T in the previous RREQ path , then forward the new RREQ, otherwise, discard the new RREQ.

9. A dynamic ad hoc networking method for walkie-talkies as claimed in claim 1, characterized in that: The optimized process of the AODV route discovery process is as follows: (1) The source node broadcasts RREQ; (2) Each intermediate node receives the RREQ and obtains the spreading factor of the previous hop node of each intermediate node, which is used as the spreading factor for the previous hop node to communicate with each intermediate node. The data packet transmission delay T is calculated under the spreading factor of the previous hop node of each intermediate node. packet ; (3) Determine whether each intermediate node has received the RREQ from the same node. If not, execute step (4); if so, execute step (5); (4) Extract the path hop count field hops and path transmission delay field T in RREQ path , with T path =T path +T packet Update RREQ with hops=hops+1, and record hops and T locally path , determine whether the preset conditions for returning RREP are met. If they are met, unicast return RREP is performed; if not, broadcast forward RREQ; (5) Extract the hops in RREQ. If the hops is less than or equal to the local record, update the RREQ and local record. If the T in the updated local record is path Less than T in the local record before the update path , then determine whether the preset conditions for returning RREP are met. If they are met, unicast return RREP is performed; if not, RREQ is broadcast and forwarded.

10. A dynamic ad hoc network system for walkie-talkies, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the dynamic self-organizing network method for walkie-talkies as described in any one of claims 1-9 are implemented.

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