A dynamic ad hoc networking method and system for intercoms

Abstract

The application relates to the technical field of wireless networking, in particular to a dynamic ad hoc networking method and system for intercoms, which comprises the following steps: for a pre-established intercom network, in the process of adjusting the transmission rate of each node by an RRAA algorithm, the length of the next window of each window of each node is obtained; the time interval of two adjacent adjustment of the spreading factor of each node is recorded as a spreading factor stable interval, whether to adjust the spreading factor of each network is evaluated by comparing the frame error rate of each node in each window and the value of MTL and ORI in the spreading factor stable interval of each window; the spreading factor of each node is adjusted; in the route discovery process of the AODV protocol, the RREQ received by each node is updated; whether to discard the non-first RREQ received by each node is evaluated; and the routing selection of the intercom is carried out according to the AODV protocol. The application aims to improve the throughput and communication performance of the intercom network.

Description

Technical Field

[0001] This application relates to the field of wireless networking technology, specifically to a dynamic self-organizing network method and system for walkie-talkies. Background Technology

[0002] Digital walkie-talkies are the most widely used mobile terminals in the field of dedicated mobile communications. During large-scale events, staff frequently use digital walkie-talkies for voice communication. Employing wireless ad hoc network technology to build a communication network among multiple digital walkie-talkies can not only extend their communication range but also enable voice communication between two walkie-talkies when the channel is blocked. In Low Power Wide Area Networks (LPWANs), LoRa (Long Range), as 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 capability. However, compared with other spread spectrum methods, the chirp modulation performance of LoRa technology depends on the size of the spreading factor SF. During large-scale events, the communication environment of the digital walkie-talkie ad hoc network changes significantly. A fixed spreading factor SF cannot adapt to the complex changes in the wireless channels between walkie-talkies, affecting the improvement of the communication performance of the digital walkie-talkie ad hoc network. At the same time, in the route discovery process of the AODV (Ad-hoc On-Demand Distance Vector) protocol, intermediate nodes only forward the first received RREQ (Route Request), and the destination node only responds to the first received RREQ, ignoring the fact that there are usually multiple available routes for sending data from the source node to the destination node in a LoRa ad hoc network. This leads to a decrease in the throughput of the walkie-talkie network, thus affecting 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 improves 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, embodiments of this application provide a method for dynamic self-organizing networks of walkie-talkies, the method comprising the following steps:

[0006] For a pre-built walkie-talkie network, during the process of 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 of each node in each window and the length of each window with the changes in the frame error rate of each node in each window and the preset number of windows before it. The initial length of the window is a preset value.

[0007] The time interval between two consecutive adjustments of the spreading factor for each node is denoted as the stable interval of the spreading factor for each node. The values ​​of the parameters MTL and ORI of the RRAA algorithm are calculated in each stable interval of the spreading factor for each node. By comparing the frame error rate of each node in each window with the values ​​of MTL and ORI in the stable interval of the spreading factor for 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 according to the difference between the frame error rate in the last window before each adjustment and the values ​​of MTL and ORI in the stable interval of the spreading factor for the last window. 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. If the number of RREQs received by each node from the same node is greater than 1, the path hop count between different RREQs received by each node from the same node and the updated transmission delay are compared to evaluate whether to discard the non-first RREQs received by each node, in order to optimize the route discovery process of AODV.

[0009] The routing of walkie-talkies is performed according to the AODV protocol.

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

[0011] Calculate the product of the frame error rate of each node within each window and the length of each window;

[0012] Arrange the frame error rates of each window of each node and the preset number of windows before them in chronological order to form the frame error rate sequence of each window of each node. Calculate the average value of all elements in the first-order difference sequence of each frame error rate sequence. Calculate the maximum value among the average values ​​calculated by all nodes. Calculate the ratio of the average value to the maximum value for each window of each node. Calculate the product of the product and the ratio.

[0013] 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 with 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 as follows:

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

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

[0018] The differences between the frame error rate in the last window before each adjustment of each node and the MTL and ORI values ​​in the stable interval of the spreading factor in the last window are denoted as the first difference and the second difference, respectively; the sum of the first difference and the second difference is calculated.

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

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

[0021] Calculate the sum of the accumulated value and 1; round the product of the accumulated sum and the spreading factor of each node before each adjustment to the nearest integer, and use the result 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 as follows:

[0023] Add a path transmission delay field T to RREQ path T path The update is made by the node that receives and forwards the RREQ. When each node receives the 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, change the T value in RREQ. path Add T packet .

[0024] In one embodiment, the process of evaluating whether to discard non-first RREQs 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, discard the new RREQ; otherwise, adjust the T in the new RREQ at each node. path And T in the previous RREQ path After the update, the updated T in the new RREQ path T is smaller than the updated T in the previous RREQ path If the condition is met, forward the new RREQ; otherwise, discard the new RREQ.

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

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

[0028] (2) Each intermediate node receives the RREQ, obtains the spreading factor of its previous hop node, uses it as the spreading factor for communication between the previous hop node and each intermediate node, and calculates the data packet transmission delay T 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 it has not received it, proceed to step (4). If it has received it, proceed to step (5).

[0030] (4) Extract the path hops field and path transmission delay field T from 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, return RREP via unicast; otherwise, broadcast and forward RREQ.

[0031] (5) Extract hops from RREQ. If hops is less than or equal to the local record, update RREQ and the local record. If the updated local record contains T... path T is less than the local record before the update. path If the conditions for returning RREP are met, then determine whether the preset conditions are met. If they are met, then unicast RREP; otherwise, broadcast RREQ.

[0032] Secondly, embodiments of this application also provide 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 the dynamic self-organizing network method for walkie-talkies described in any one of the above-mentioned embodiments.

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

[0034] This application, by dynamically adjusting the window length, can more accurately reflect changes in channel quality, avoiding problems such as inaccurate frame error rate statistics or excessively long response time of the RRAA algorithm caused by excessively large or small windows, thus ensuring the real-time performance 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 end-to-end delay and channel occupancy time, and improving the accuracy and efficiency of routing selection. By evaluating whether to discard non-first RREQs received by each node, the problem of excessively long routing path delay caused by directly discarding RREQs can be avoided, improving the accuracy and efficiency of routing selection, thereby enhancing the throughput and communication performance of the walkie-talkie network. Attached Figure Description

[0036] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 A flowchart illustrating the steps of a dynamic self-organizing network method for walkie-talkies provided in one embodiment of this application;

[0038] Figure 2 A flowchart illustrating the window length adjustment process;

[0039] Figure 3 This is a schematic diagram of the optimized AODV route discovery process. Detailed Implementation

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

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. It should be understood that, unless otherwise stated, " / " in this application means "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 description, in conjunction with the accompanying drawings, details a specific scheme for a dynamic self-organizing network method and system for walkie-talkies provided in this application.

[0044] Please see Figure 1 The diagram illustrates a flowchart of a dynamic self-organizing network method for walkie-talkies according to an embodiment of this application. The method includes the following steps:

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

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

[0047] The walkie-talkie network in this embodiment adopts a distributed architecture, where all nodes are equal and can complete communication tasks without relying on a central base station. Each node has sending, receiving, and relay functions, supporting single-hop or multi-hop data transmission. Specifically, when the direct connection path between two walkie-talkies fails due to an obstacle, the walkie-talkie network will automatically select a detour path through other walkie-talkies to complete the communication.

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

[0049] In walkie-talkie networks, there is a relationship between the transmission rate and signal strength of a node. Because the distance between the transmitting node and other nodes within the coverage area varies, channel attenuation from the transmitting node to each node results in varying signal strength at each node. If the signal is too weak and the transmission rate is too high, reception will be impossible; conversely, if the signal is strong and the transmission rate is too low, communication resources will be wasted. Considering the complexity of wireless communication environments at large events, a single transmission rate cannot meet the communication needs of all digital walkie-talkie nodes. Therefore, it is necessary to dynamically adjust the transmission rate between nodes based on the actual situation.

[0050] In 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, and vice versa. In this embodiment, when the channel state between nodes changes, the transmission rate is changed by altering the spreading factor SF of the transmitting node, thereby improving the communication performance of the walkie-talkie network. Specifically, before transmitting data frames, the transmitting node considers the channel state of each path and calculates the spreading factor SF for different paths to meet the different communication needs of all nodes in the walkie-talkie network, achieving adaptive transmission rate. The RRAA (Robust Rate Adaptation Algorithm) algorithm is an open-loop rate adaptive algorithm. It determines the change in transmission rate by statistically analyzing the frame error rate over a period of time and comparing it with the parameters MTL (Maximum Tolerable Threshold) and ORI (Opportunistic Rate Increase Threshold) in the RRAA algorithm. Therefore, the size of the window used to statistically analyze the frame error rate directly affects the performance of the RRAA algorithm. On the one hand, a window that is too small will result in inaccurate statistics on the frame error rate; on the other hand, a window that is too large will increase the reaction time of the RRAA algorithm, making it unable to reflect the channel status in real time.

[0051] Step 2.1: By using the frame error rate of each node in each window and the length of each window in the walkie-talkie network, and combining the changes in the frame error rate of each node in each window and the preset number of windows before it, obtain the length of the next window of each node.

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

[0053] In this embodiment, the initial length of the window is 20 frames. Based on the premise that the maximum window length is 40 frames and the minimum is 5 frames, the implementer can set the initial length of the window according to the actual situation.

[0054] In this embodiment, the preset quantity is 20. The preset quantity is set manually, and the implementer can set it according to the actual situation. 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 personnel movement during large-scale events is the main cause of channel environment changes, and that this movement is often regional, significant differences in channel environment changes exist between different nodes in the walkie-talkie network. To avoid excessive window growth in the RRAA algorithm due to drastic changes in the walkie-talkie network channel environment, the window length and its growth rate are limited by comparing the quality changes of all channels in the walkie-talkie network. This ensures that the window's frame error rate can promptly reflect changes in channel quality.

[0056] Based on the above analysis, the length of the next window for each node is obtained by considering the frame error rate of each node within each window, the length of each window, and the changes in the frame error rate sequence of each window for each node. The expression is as follows:

[0057] In the formula, W j,i W j,i+1 These represent the lengths of the i-th and (i+1)-th windows of the j-th node, respectively; ceil() represents the floor function; ΔW j,i μ represents the change in 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 within the i-th window and the length of the i-th window; j,i Let μ be the mean of all elements in the first-order difference sequence of the frame error rate sequence of the i-th window at the j-th node; calculate the average of all elements in the first-order difference sequence of the frame error rate sequence of each window at each node, μ. max This represents the maximum value among the average values ​​calculated by all nodes in the walkie-talkie network. It is used to limit the window length and its growth rate, enabling dynamic window selection and ensuring real-time channel assessment. A schematic diagram of the window length adjustment process is shown below. Figure 2 As shown.

[0058] Step 2.2: Denote the time interval between two consecutive adjustments of the spreading factor for each node as the stable interval of the spreading factor for each node. Calculate the values ​​of the parameters MTL and ORI of the RRAA algorithm within each stable interval of the spreading factor for each node. By comparing the frame error rate of each node within each window with the values ​​of MTL and ORI within the stable interval of the spreading factor for each window, assess whether to adjust the spreading factor of each network. If adjustment is required, adjust the spreading factor of each node by comparing the frame error rate of each node within the last window before each adjustment with the values ​​of MTL and ORI within the stable interval of the spreading factor for the last window.

[0059] Furthermore, the RRAA algorithm determines whether to adjust the spreading factor based on the frame error rate of each node within each window. The time interval between two consecutive adjustments of the spreading factor for each node is denoted as the stable interval of the spreading factor for each node. The values ​​of MTL and ORI for each node within each stable interval of the spreading factor are calculated. If the frame error rate of any node within each window is simultaneously greater than the values ​​of MTL and ORI within the stable interval of the spreading factor for each window, then the spreading factor SF of that node as a transmitting node is increased; if the frame error rate of any node within each window is simultaneously less than 0.5 times the value of MTL and 0.5 times the value of ORI within the stable interval of the spreading factor for each window, then the spreading factor SF of that node as a transmitting node is decreased; otherwise, the spreading factor SF of that node remains unchanged. The calculation methods of MTL and ORI are well-known techniques and will not be described in detail in this application; 0.5 is merely one embodiment of this application, and implementers can set their specific values ​​according to actual conditions, provided that the values ​​are greater than 0 and less than 1.

[0060] Furthermore, when the spreading factor needs adjustment, for each adjustment, the spreading factor after each adjustment is obtained by using the spreading factor of each node before each adjustment, and 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 interval of the spreading factor in the last window. The expression is as follows:

[0061] SF′ j,n =round[SF j,n ×(1+ΔMTL n +ΔORI n In the formula, SF j,n SF′ j,n These represent the spreading factors of the j-th node before and after the nth adjustment, respectively; round[] represents the rounding function; ΔMTL n ΔORI nThis represents the difference between the frame error rate in the last window before the nth adjustment of the j-th node and the MTL and ORI values ​​within the stable interval of the spreading factor of 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 by human intervention. Based on the premise that the initial value of the spreading factor is an integer within the range [6,12], the implementer can set the specific value of the initial value of the spreading factor according to the actual situation.

[0063] Step 3: In the route discovery process of the AODV protocol, the RREQ received by each node is updated based on the data packet transmission delay under the spreading factor of the previous hop node. If the number of RREQs received by each node from the same node is greater than 1, the path hop count between different RREQs received by each node from the same node and the updated transmission delay are compared to evaluate whether to discard the non-first RREQs received by each node, in order to optimize the AODV route discovery process. The route selection for the walkie-talkie is performed according to the AODV protocol.

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

[0065] Add a path transmission delay field T to the Route Request (RREQ). path T path The node that receives and forwards the RREQ updates the T. path The size 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 communication between the previous hop node and other nodes. Simultaneously, it calculates the data packet transmission delay T under the spreading factor of the previous hop node. packet If RREQ needs to be forwarded, then when updating RREQ, remove the T value from RREQ. path Add T packet To achieve T path The update process is as follows. Simultaneously, when nodes receive the same RREQ from the same node again, they first check if the path hop count in the new RREQ is greater than the previous RREQ. If it is, the new RREQ is discarded; otherwise, the T value in the new RREQ is compared. path T in the previous RREQ path If each node corresponds to T in the new RREQpath And T in the previous RREQ path After the update, the updated T in the new RREQ path T is smaller than the updated T in the previous RREQ path If the new RREQ is found, it is forwarded; otherwise, it is discarded. This avoids the problem of excessively long routing path delays caused by the AODV protocol directly discarding the RREQ.

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

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

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

[0070] (3) Determine whether each intermediate node has received the RREQ from the same node. If it has not received it, proceed to step (4). If it has received it, proceed to step (5).

[0071] (4) Extract the path hops field and the path transmission delay field T from RREQ. path , with T path =T path +T packet Update RREQ with hops = hops + 1, and record hops and T locally. path It determines whether the preset conditions for returning RREP are met. If they are met, it unicasts and returns RREP (Route Reply); otherwise, it broadcasts and forwards RREQ.

[0072] (5) Extract hops from RREQ. If hops is less than or equal to the local record, update RREQ and the local record. If the updated local record contains T... path T is less than the local record before the update. path If the preset conditions for returning RREP are met, then it is determined whether they are met. If they are met, an RREP is returned via unicast; otherwise, an RREQ is broadcast forwarded. The optimized AODV route discovery process is illustrated in the diagram below. Figure 3 As shown.

[0073] If the address of the intermediate node is the same as the address of the destination requested in RREQ, or if the intermediate node has routing information to the target node, then the condition for returning RREP is met.

[0074] Furthermore, the routing selection of the walkie-talkie is implemented according to the AODV protocol. The specific process of implementing the routing selection of the walkie-talkie 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, this application embodiment 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-described dynamic self-organizing network methods for walkie-talkies.

[0076] In summary, this application, by dynamically adjusting the window length, can more accurately reflect changes in channel quality, avoiding inaccurate frame error rate statistics or excessively long response times in the RRAA algorithm caused by excessively large or small windows, thus ensuring the real-time performance 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 channel quality changes. Dynamically adjusting the spreading factor 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 end-to-end delay and channel occupancy time, and improving the accuracy and efficiency of routing selection. By evaluating whether to discard non-first RREQs received by each node, the problem of excessively long routing path delay caused by directly discarding RREQs can be avoided, improving the accuracy and efficiency of routing selection, thereby enhancing the throughput and communication performance of the walkie-talkie network.

[0078] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending 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 blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0079] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from its essential characteristics. Therefore, the embodiments described above should be considered exemplary and non-limiting in all respects.

Claims

1. A method for dynamic ad hoc networking of intercoms, characterized in that, The method includes the following steps: For a pre-built walkie-talkie network, during the process of 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 of each node in each window and the length of each window with the changes in the frame error rate of each node in each window and the preset number of windows before it. The initial length of the window is a preset value. The time interval between two consecutive adjustments of the spreading factor for each node is denoted as the stable interval of the spreading factor for each node. The values ​​of the parameters MTL and ORI of the RRAA algorithm are calculated in each stable interval of the spreading factor for each node. By comparing the frame error rate of each node in each window with the values ​​of MTL and ORI in the stable interval of the spreading factor for 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 according to the difference between the frame error rate in the last window before each adjustment and the values ​​of MTL and ORI in the stable interval of the spreading factor for 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 the previous hop node. If the number of RREQs received by each node from the same node is greater than 1, the path hop count between different RREQs received by each node from the same node and the updated transmission delay are compared to evaluate whether to discard the non-first RREQs received by each node, in order to optimize the route discovery process of AODV. The routing of walkie-talkies is performed according to the AODV protocol.

2. The method for dynamic ad hoc networking for intercoms of claim 1, wherein, The process of obtaining the length of the next window for each window of each node is as follows: Calculate the product of the frame error rate of each node within each window and the length of each window; Arrange the frame error rates of each window of each node and the preset number of windows before them in chronological order to form the frame error rate sequence of each window of each node. Calculate the average value of all elements in the first-order difference sequence of each frame error rate sequence. Calculate the maximum value among the average values ​​calculated by all nodes. Calculate the ratio of the average value to the maximum value for each window of each node. Calculate 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 with the product value.

3. The method for dynamic ad hoc networking of a speakerphone according to claim 2, wherein, 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. The method for dynamic ad hoc networking of a speakerphone of claim 1, wherein, The method for assessing whether to adjust the spreading factor of each network is as follows: If the frame error rate of any node in each window is simultaneously greater than the values ​​of MTL and ORI within the stable interval of the spreading factor for each window, or if the frame error rate of any node in each window is simultaneously less than a preset proportion of the MTL value and a preset proportion of the ORI value within the stable interval of the spreading factor for each window, then the spreading factor of that node is adjusted; otherwise, no adjustment is made.

5. The method for dynamic ad hoc networking of a speakerphone of claim 1, wherein, The process of adjusting the spreading factor of each node is as follows: The differences between the frame error rate in the last window before each adjustment of each node and the MTL and ORI values ​​in the stable interval of the spreading factor in the last window are respectively denoted as the first difference and the second difference. Calculate the sum of the first difference and the second difference; The spreading factor of each node after each adjustment is obtained by combining the spreading factor of each node before each adjustment with the accumulated value.

6. The method for dynamic ad hoc networking of a speakerphone according to claim 5, wherein, The method for calculating the spreading factor of each node after each adjustment is as follows: Calculate the sum of the accumulated value and 1; round the product of the accumulated sum and the spreading factor of each node before each adjustment to the nearest integer, and use the result as the spreading factor of each node after each adjustment.

7. A dynamic self-organizing network method for walkie-talkies as described in claim 1, characterized in that, The method for updating the RREQ received by each node is as follows: Add a path transmission delay field to RREQ , The update is made by the node that receives and forwards the RREQ. When each node receives the RREQ, it obtains the spreading factor of the previous hop node and calculates the data packet transmission delay under the spreading factor of the previous hop node. When updating RREQ, the values ​​in RREQ will be... Plus .

8. The method for dynamic ad hoc networking of a speakerphone according to claim 7, wherein, The process of evaluating whether to discard non-first RREQs 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, discard the new RREQ; otherwise, update the path hop count in the new RREQ at each node. And in the previous RREQ After the update, the new RREQ will have an updated version. Smaller than the previous RREQ update If the condition is met, forward the new RREQ; otherwise, discard the new RREQ.

9. The method for dynamic ad hoc networking of a speakerphone according to claim 1, wherein, The optimized routing discovery process for AODV is as follows: (1) The source node broadcasts RREQ; (2) Each intermediate node receives the RREQ, obtains the spreading factor of its previous hop node, uses it as the spreading factor for communication between the previous hop node and each intermediate node, and calculates the data packet transmission delay under the spreading factor of the previous hop node of each intermediate node. ; (3) Determine whether each intermediate node has received the RREQ from the same node. If it has not received it, proceed to step (4). If it has received it, proceed to step (5). (4) Extract the path jump number segment from RREQ and path transmission delay field ,by and Update RREQ, and Record and update locally and It determines whether the preset conditions for returning RREP are met. If they are met, it unicasts and returns RREP; otherwise, it broadcasts and forwards RREQ. This indicates the path transmission delay field in the updated RREQ. This indicates the path jump number segment in the updated RREQ; (5) Extracting from RREQ ,if If the value is less than or equal to the local record, then update RREQ and the local record. If the updated local record contains... Smaller than the local record before the update If the conditions for returning RREP are met, then determine whether the preset conditions are met. If they are met, then unicast RREP; otherwise, broadcast RREQ.

10. A dynamic ad hoc network system for a speakerphone, 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, it implements the steps of the dynamic self-organizing network method for walkie-talkies as described in any one of claims 1-9.

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