An indoor weak signal area relay coverage optimization method based on D2D terminal cooperation

Abstract

The application relates to the technical field of wireless communication management, in particular to a relay coverage optimization method in an indoor weak signal area based on D2D terminal cooperation, which comprises the following steps: a relay coverage optimization method based on D2D terminal cooperation, identification of a high-load node, dynamic adjustment of a relay path and optimization of weak signal coverage. In the application, periodic collection and interval analysis are carried out on the forwarding behavior of D2D terminal nodes, a dynamic mapping relationship between node numbers and forwarding intervals is established, real-time identification and trend prediction of node communication load changes can be realized, the identification accuracy and timeliness of high-load relay nodes are improved by combining a high-frequency window group mean value analysis mechanism, intelligent selection of optimal replacement nodes is realized, an upstream and downstream channel relationship is constructed by combining node local cache information synchronization, channel link relationship recombination and real-time reconstruction of path topology are effectively completed, and problems such as static relay configuration lag, channel management rigidity and insufficient communication resource utilization are solved.

Description

Technical Field

[0001] This invention relates to the field of wireless communication management technology, and in particular to a method for optimizing relay coverage in indoor weak signal areas based on D2D terminal collaboration. Background Technology

[0002] The field of wireless communication management technology mainly involves the unified management of wireless resource allocation, connection control, communication path organization, and coverage scheduling in wireless communication systems. It involves methodological design of control strategies for the connection relationships, signal transmission paths, and communication processes between terminal devices and network nodes to ensure the continuity and stability of wireless communication under different environmental conditions. Typically, it revolves around the access, scheduling, forwarding, and coverage organization of wireless signals, employing a collaborative approach between the network and terminal sides to plan and manage signal transmission links. Among these methods, the traditional indoor weak signal area relay coverage optimization method addresses the problem of wireless signal attenuation caused by wall structures, floor levels, or complex layouts within buildings. This method selects terminal devices with communication capabilities as relay nodes in weak signal areas. After receiving downlink signals from the base station, the terminal forwards the signal, or during uplink communication, it relays communication data from other terminals through the link established between itself and the base station. Based on pre-set relay selection conditions, communication distance, and signal strength thresholds, the relay terminals are configured to complete the communication connection and coverage organization in indoor weak signal areas.

[0003] Existing relay coverage methods for weak indoor signal areas rely too heavily on statically set relay selection criteria and signal strength thresholds, lacking the ability to dynamically evaluate the actual forwarding behavior of nodes. This leads to discrepancies between relay node allocation results and actual network load conditions. When relay nodes are under high load for extended periods, they cannot be identified and replaced in a timely manner, resulting in decreased signal forwarding stability. Furthermore, existing solutions fail to fully utilize and allocate idle terminal resources, causing some potentially available terminals to remain unactivated, further exacerbating communication link congestion and affecting overall signal coverage and communication continuity. In particular, in complex scenarios involving multiple nodes, the lack of in-depth discrimination and response mechanisms for inter-node behavior patterns makes it difficult to flexibly adjust and optimize channel connection status, thus limiting the dynamic adaptability of relay coverage strategies and the efficiency of local area coverage. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a method for optimizing relay coverage in indoor weak signal areas based on D2D terminal collaboration, comprising the following steps: To achieve the above objectives, the present invention adopts the following technical solution: a method for optimizing relay coverage in indoor weak signal areas based on D2D terminal collaboration, comprising the following steps: S1: Collect D2D terminal node number information, collect all downlink signal forwarding timestamps within the period and calculate the forwarding interval, perform the mapping between node number and forwarding interval, and output the node forwarding interval mapping structure; S2: Read the time series data in the node forwarding interval mapping structure, construct window groups based on every three consecutive periods, determine the downward trend of each window group, mark high-load relay nodes, and output a list of relay node load warnings; S3: Based on the relay node load warning list, filter out the D2D terminal nodes that are idle within the communication radius of each high-load relay node, filter out new relay nodes, and output the relay role transfer target node number. S4: Read the target node number of the relay role transfer, synchronously obtain the path channel number, synchronization clock parameters and link index information through the node local cache, establish the channel relationship mapping from the new relay node to the upstream and downstream devices, and output the new relay path topology parameter set; S5: Based on the new relay path topology parameter set, locate the corresponding indoor weak signal area, filter candidate path numbers that match the corresponding area, activate path items with available connection status, and output the weak signal area relay coverage optimization record.

[0005] As a further aspect of the present invention, the high-load relay node specifically refers to determining whether the window group shows a decreasing trend in forwarding interval twice consecutively and calculating the decreasing magnitude. If the decreasing magnitude exceeds the set forwarding offset threshold, the corresponding node number is marked as a high-load relay node.

[0006] As a further aspect of the present invention, the new relay node specifically refers to the method of calculating the ratio of the idle time and the signal forwarding success frequency of the idle D2D terminal node in the current period, sorting the two parameters, and selecting the node number with the highest ranking as the new relay node.

[0007] As a further embodiment of the present invention, the node forwarding interval mapping structure includes forwarding behavior pattern characteristics, node forwarding activity labels, and time series fluctuation indicators; the relay node load warning list includes high-load node numbers, load anomaly trend levels, and periodic forwarding density factors; the relay role transfer target node number includes target node identifier, availability performance ratio, and channel switching priority; the new relay path topology parameter set includes inter-node channel number index, synchronization clock offset parameters, and link connection direction labels; and the weak signal area relay coverage optimization record includes optimized path number, area signal coverage level, and active path status marker.

[0008] As a further aspect of the present invention, the step of obtaining the node forwarding interval mapping structure is as follows: S111: Obtain all D2D terminal node number information, collect all downlink signal forwarding timestamps of each terminal node within a set period, calculate the difference between adjacent items in the timestamp sequence based on each node number, classify and store the calculated time difference according to the node number, and generate a node forwarding interval data sequence set. S112: Based on the node forwarding interval data sequence set, for each node's corresponding forwarding interval data sequence, detect whether there are abrupt changes in the time interval in the sequence. If so, perform interpolation completion processing based on adjacent valid interval values ​​to obtain the completed node forwarding interval sequence set. S113: Based on the completed node forwarding interval sequence set, construct a one-to-one correspondence structure between each node number and the corresponding forwarding interval sequence, aggregate all entries to form a unified structure, and obtain the node forwarding interval mapping structure.

[0009] As a further aspect of the present invention, the step of obtaining the relay node load warning list is as follows: S211: Read the forwarding interval sequence data in the node forwarding interval mapping structure, extract the time series according to each node number, divide each sequence into a continuous time window group with a length of three periods according to the time order, calculate the average value of all interval values ​​in each window group, and generate a node period mean sequence set. S212: Based on the node periodic mean sequence set, for the mean sequence corresponding to each node number, extract the mean of three adjacent windows, compare the numerical difference between the first two mean and the last two mean, if the mean decreases twice in a row, and the decrease is greater than the set forwarding offset threshold each time, then mark the corresponding node number as a high-load relay node to obtain the overload node number set. S213: Based on the set of overload node numbers, establish a number index entry for each marked node number, aggregate all marked information into a unified data list structure, complete the sorting of all marked node information, and obtain the relay node load warning list.

[0010] As a further aspect of the present invention, the step of obtaining the relay role transfer target node number is as follows: S311: Based on the node number information in the relay node load warning list, retrieve the communication radius range of each high-load relay node in the current period, detect the current status of all D2D terminal nodes within the range, filter out nodes that are in signal forwarding or in an occupied state, retain only the node numbers that are not participating in the forwarding task, and generate a set of idle nodes within the communication radius. S312: Based on the set of idle nodes within the communication radius, collect the continuous idle duration and corresponding signal forwarding success frequency of each node in the set in the current period, construct a ratio expression based on the idle duration and forwarding success frequency of each node, calculate the ratio result of each node, and store the ratio with the node number to obtain the idle forwarding ratio mapping structure. S313: According to the idle forwarding ratio mapping structure, sort all ratio results in descending order of numerical value, extract the node number corresponding to the first item in the sorting result as the preferred target for the current relay role transfer, and output the corresponding node number to obtain the target node number for the relay role transfer.

[0011] As a further aspect of the present invention, the step of obtaining the new relay path topology parameter set is as follows: S411: Read the target node number of the relay role transfer, collect the path channel number parameters, synchronization clock configuration parameters and link index identification information associated with the node according to the local cache configuration content of the node number index, decompose the collected parameters into independent data, and generate a node cache parameter field set. S412: Based on the node cache parameter field set, the path channel number and link index identifier are combined and processed. According to the upstream and downstream device types and connection relationships marked by the link index identifier, the channel number corresponding allocation from the new relay node to the upstream and downstream devices is completed, and the point-to-point connection relationship structure between devices is constructed to obtain the relay node channel mapping structure. S413: Based on the relay node channel mapping structure, aggregate the channel number, link direction, and synchronization clock offset parameters corresponding to each connection link, and classify all link items by node number and write them into the topology structure to establish a new relay path topology parameter set.

[0012] As a further aspect of the present invention, the step of obtaining the relay coverage optimization record in the weak signal area is as follows: S511: Based on the new relay path topology parameter set, extract the node number and link parameter information involved in each relay path, retrieve the corresponding wireless coverage layer according to the spatial coordinates of the path terminal node, match the grid cell whose signal strength identification field is lower than the set standard value in the area, mark the location as an indoor weak signal area, and establish the binding relationship between the number and the spatial index to generate a weak signal area location index table. S512: Based on the weak signal area location index table, match the spatial coordinates of each identified area with the path number configuration in the path resource pool, retrieve the connection status, and if the identified status is available, write the path number into the matching set to obtain a list of available path numbers in the area. S513: Based on the list of available path numbers in the area, activate the connection status of each candidate path item, modify the path status to the active state, mark and record the path numbers that have completed the activation process, aggregate the area number, path number and status flag information, and establish a relay coverage optimization record for weak signal areas.

[0013] Compared with the prior art, the advantages and positive effects of the present invention are as follows: In this invention, by periodically collecting and analyzing the forwarding behavior of D2D terminal nodes, a dynamic mapping relationship between node number and forwarding interval is established, enabling real-time identification and trend prediction of changes in node communication load. Combined with a high-frequency window group mean analysis mechanism, the accuracy and timeliness of identifying high-load relay nodes are improved. Through idle node screening and performance ratio ranking, the optimal replacement node is intelligently selected. Combined with node local cache information, upstream and downstream channel relationships are synchronously constructed, effectively completing the reorganization of channel link relationships and real-time reconstruction of path topology. By activating and confirming the status of available paths, the elasticity of relay coverage in weak signal areas is significantly enhanced, solving problems such as lagging static relay configuration, rigid channel management, and insufficient utilization of communication resources. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the steps of the present invention; Figure 2 This is a flowchart of the node forwarding interval mapping structure acquisition process of the present invention; Figure 3 This is a flowchart of the process for obtaining the relay node load warning list in this invention; Figure 4 This is a flowchart of the process for obtaining the target node number for relay role transfer in this invention; Figure 5 This is a flowchart illustrating the process of obtaining the new relay path topology parameter set in this invention. Figure 6 This is a flowchart of the relay coverage optimization record acquisition process in weak signal areas according to the present invention. Detailed Implementation

[0016] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0017] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0018] In the embodiments of this invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning. Similarly, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, they convey the same meaning.

[0019] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0020] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0021] Please see Figure 1 This invention provides a method for optimizing relay coverage in indoor weak signal areas based on D2D terminal collaboration, comprising the following steps: S1: Collect all D2D terminal node number information, collect all downlink signal forwarding timestamps of each D2D terminal node in the period, and form a forwarding interval data sequence by calculating the difference between each adjacent timestamp, perform mapping between node number and forwarding interval, and output node forwarding interval mapping structure. S2: Read the time series data in the node forwarding interval mapping structure, construct a window group based on every three consecutive periods, calculate the average forwarding interval in each window group, determine whether the forwarding interval decreases twice in a row, and if the decrease exceeds the set forwarding offset threshold, mark the corresponding node number as a high-load relay node and output the relay node load warning list. S3: Based on the node number information in the relay node load warning list, filter the D2D terminal nodes that are idle within the communication radius of each high-load relay node, count the idle time and signal forwarding success frequency in the current period, calculate the ratio of the two parameters and sort them, select the node number with the highest ranking as the new relay node, and output the relay role transfer target node number. S4: Read the target node number of the relay role transfer, synchronously obtain the path channel number, synchronization clock parameters and link index information through the node's local cache, establish the channel relationship mapping from the new relay node to the upstream and downstream devices, and output the new relay path topology parameter set; S5: Based on the new relay path topology parameter set, locate the corresponding indoor weak signal area, filter candidate path numbers that match the corresponding area, activate path items with the connection status as available, confirm the path status, and output the relay coverage optimization record for the weak signal area.

[0022] The node forwarding interval mapping structure includes forwarding behavior pattern characteristics, node forwarding activity labels, and time series fluctuation indicators. The relay node load warning list includes high-load node numbers, load anomaly trend levels, and periodic forwarding density factors. The relay role transfer target node number includes target node identifier, availability performance ratio, and channel switching priority. The new relay path topology parameter set includes inter-node channel number index, synchronization clock offset parameters, and link connection direction labels. The weak signal area relay coverage optimization record includes optimized path number, area signal coverage level, and active path status marker.

[0023] Please see Figure 2 The specific steps of S1 are as follows: S111: Obtain all D2D terminal node number information, collect all downlink signal forwarding timestamps of each terminal node within a set period, calculate the difference between adjacent items in the timestamp sequence based on each node number, classify and store the calculated time difference according to the node number, and generate a node forwarding interval data sequence set. Regarding the acquisition of D2D terminal node numbering information and the collection of downlink signal forwarding timestamps, in an implementation scenario with three D2D terminal nodes, the nodes are numbered 1, 2, and 3. The downlink signal forwarding behavior of each node is continuously monitored within the same statistical period. During monitoring, the system clock records the time of each forwarding, forming an array of timestamps arranged in ascending order of time. For example, node 1 records timestamps of 100ms, 130ms, 165ms, and 205ms within the period; node 2 records timestamps of 110ms, 150ms, and 190ms; and node 3 records timestamps of 95ms, 140ms, 185ms, and 235ms. Based on this, a difference calculation is performed on adjacent timestamps of node 1. Subtracting 100 from 30 gives 30ms, subtracting 130 from 165 gives 35ms, and subtracting 165 from 205 gives 40ms. Node 2 corresponds to 40ms and 40ms, and Node 3 corresponds to 45ms, 45ms, and 50ms. All the above difference calculations are performed in milliseconds, and each calculation is explicitly performed by subtracting the previous timestamp from the next timestamp. Then, the difference results obtained from each node are aggregated according to the node number. The interval array corresponding to Node 1 is 30, 35, and 40, Node 2 is 40 and 40, and Node 3 is 45, 45, and 50. This aggregated structure is used as the basic data for subsequent processing, and finally a node forwarding interval data sequence set is formed in which the node number is associated with its corresponding forwarding time interval array.

[0024] Table 1. Node forwarding timestamps and interval data. As shown in Table 1, the table lists the timestamp collection results of each node in the embodiment and the forwarding interval data obtained by the adjacent difference calculation.

[0025] S112: Based on the node forwarding interval data sequence set, for each node's corresponding forwarding interval data sequence, detect whether there are abrupt changes in the time interval in the sequence. If so, perform interpolation and completion processing based on adjacent valid interval values ​​to obtain the completed node forwarding interval sequence set. Based on the aforementioned node forwarding interval data sequence set, the forwarding interval sequence of each node is examined in its original time order. In the implementation scenario, the change range between adjacent intervals is used as the judgment criterion. Sequences 30, 35, and 40 of node 1 are compared item by item. The difference between 35 and 30 is calculated to be 5ms, and the difference between 40 and 35 is also 5ms. This difference is compared with a manually set change reference value of 20ms. Since neither exceeds this reference value, it is determined that the sequence of node 1 does not have any abnormal jumps. The same processing is performed on sequences 40 and 40 of node 2. The adjacent difference is 0ms, and the processing condition is not triggered. Sequences 45 and 45 of node 3 are then processed. The adjacent differences between 50 and 45 are calculated. The difference between 45 and 45 is 0ms, and the difference between 50 and 45 is 5ms, both of which are within the reference range. If a combination of 30ms and 80ms appears in a certain node, and the difference between the two is 50ms, then the arithmetic mean of the remaining valid intervals of that node is used for completion processing. For example, if the remaining valid values ​​are 30ms and 35ms, the average value is 32.5ms, and this value is used to replace the outlier. In this embodiment, this situation did not occur. Therefore, each node sequence retains its original value. Only the sequence consistency is confirmed and the structure is sorted out. Finally, a complete set of node forwarding interval sequences that can be directly used for mapping construction is obtained.

[0026] S113: Based on the completed node forwarding interval sequence set, construct a one-to-one correspondence structure between each node number and the corresponding forwarding interval sequence, aggregate all entries to form a unified structure, and obtain the node forwarding interval mapping structure. After obtaining the complete set of node forwarding interval sequences, a mapping construction operation is performed on each node number and its corresponding forwarding interval sequence. In the implementation scenario, the node number is used as the index key to establish a key-value association between node 1 and its sequences 30, 35, and 40; node 2 and its sequences 40 and 40; and node 3 and its sequences 45, 45, and 50. During the construction process, mapping entries are written one by one, and the uniqueness of each entry is checked to avoid duplicate associations of the same node number. Then, all mapping entries are aggregated to form a unified data structure. In this structure, each node number corresponds to only one complete set of forwarding interval sequences. For example, when searching for node 2, the sequence 40 and 40 can be directly located. This mapping structure remains in a static storage state throughout the entire cycle and no further modification operations are performed on the sequence content. Thus, the structured correspondence between node numbers and forwarding interval sequences is completed, and the node forwarding interval mapping structure is finally obtained.

[0027] Please see Figure 3 The specific steps of S2 are as follows: S211: Read the forwarding interval sequence data in the node forwarding interval mapping structure, extract the time series according to each node number, divide each sequence into a continuous time window group with a length of three periods according to the time order, calculate the average value of all interval values ​​in each window group, and generate a node period mean sequence set. Based on the node numbers and their corresponding forwarding interval time sequences in the node forwarding interval mapping structure, the data of nodes numbered A, B, and C are extracted as processing objects. The forwarding interval sequence of each node is sorted according to the period identifier, with the corresponding period numbers set as T1, T2, T3, T4, T5, and T6. A sliding window group is constructed with three consecutive periods as units, i.e., T1 to T3 is the first window, T2 to T4 is the second window, and so on. For node A, its forwarding interval sequence is 25ms, 27ms, 24ms, 22ms, 21ms, and 23ms. Four windows are formed according to the above rules, corresponding to the sequence groups {25, 27, 24}, {... ... �₀⁵" logs " "" logs " 25ms2525252525252525252525252525252525 {27, 24, 22}, {24, 22, 21}, {22, 21, 23}, call the forwarding interval value of each window group, and perform the mean calculation operation. For example, the mean of 25, 27, 24 in window 1 is (25+27+24) / 3=25.33ms, the mean of window 2 is (27+24+22) / 3=24.33ms, and so on. Repeat this process for nodes B and C, and independently construct the mean sequence for each node. Each mean result corresponds to the three period numbers it covers, and obtain the mapping structure between the node number and the mean of the corresponding sliding window sequence to form a periodic mean sequence, and finally generate a set of node periodic mean sequences.

[0028] S212: Based on the node periodic mean sequence set, for the mean sequence corresponding to each node number, extract the mean of three adjacent windows, compare the numerical difference between the first two mean and the last two mean, if the mean decreases twice in a row, and the decrease is greater than the set forwarding offset threshold each time, then mark the corresponding node number as a high-load relay node, and obtain the overload node number set. The periodic mean sequence of node A in the node periodic mean sequence set is read as 25.33ms, 24.33ms, 22.33ms, and 22ms. Starting from the first mean, three overlapping window groups are extracted sequentially from this sequence: {25.33, 24.33}, {24.33, 22.33}, and {22.33, 22}. The difference between adjacent values ​​is calculated: the decrease in the first group is 25.33 - 24.33 = 1.00ms, the decrease in the second group is 24.33 - 22.33 = 2.00ms, and the decrease in the third group is 22.33 - 22.00 = 0.33ms. A transition is then set... The offset threshold is 1.5ms. Each decrease amplitude is compared with this threshold to determine whether two consecutive decrease amplitudes are greater than the threshold. Only the second group meets the condition. Node A does not meet the condition of two consecutive decrease trends. If the corresponding sequence of node B is 28.5, 26.2, 24.0, 22.0, then the change amplitudes are 2.3, 2.2, 2.0ms respectively, all greater than 1.5ms, and meet the condition of two consecutive decrease trends. Then the number of node B is included in the judgment mark set. If the sequence of node C is 26.1, 26.0, 26.3, 25.9, then the decrease fluctuation amplitude does not reach the set threshold and is not marked. Finally, the overload node number set is obtained.

[0029] S213: Based on the set of overload node numbers, establish a number index entry for each marked node number, aggregate all marked information into a unified data list structure, complete the sorting of all marked node information, and obtain the relay node load warning list; Based on the marked node numbers in the overload node number set, the nodes are indexed by number, and a mapping item with the structure fields "node number", "period range", and "decline amplitude" is constructed. This structure is then organized into a list format for unified storage. In this implementation scenario, node B is the only marked object, with a period range of T1 to T4 and a maximum decline amplitude of 2.3ms. A corresponding record table entry is created and written into the index entry. Combined with other marked nodes, the data is sorted in ascending order by number to form a structured data set. This set is then output as a data framework for alarm identification, ultimately obtaining the relay node load warning list.

[0030] Table 2 Relay Node Early Warning Information Table As shown in Table 2, node B was recorded in the warning list because its average value decreased by more than the offset threshold in two consecutive instances. The information in the table corresponds to the node's periodic average value sequence, which supports the formulation of subsequent node control strategies.

[0031] Please see Figure 4 The specific steps of S3 are as follows: S311: Based on the node number information in the relay node load warning list, retrieve the communication radius range of each high-load relay node in the current period, detect the current status of all D2D terminal nodes within the range, filter out nodes that are in signal forwarding or in an occupied state, retain only the node numbers that are not participating in forwarding tasks, and generate a set of idle nodes within the communication radius. Based on the high-load relay node numbers in the relay node load warning list, the spatial coordinates of each node are located one by one. The applicable communication radius configuration parameters for the current period are extracted, and the communication radius is set to 150 meters. A two-dimensional coverage area centered on the node coordinates is constructed based on this radius. Real-time status monitoring is performed on all D2D terminal nodes within the coverage area, and the task status flag field of each node is collected. If the value of this field is 0, it indicates that the node is in an idle state; if it is 1 or 2, it represents that it is in a receiving or forwarding state. A conditional judgment operation is performed on the above fields, and only the node numbers with a flag field of 0 are retained. The results are written into the candidate set corresponding to the current relay node. For example, the coordinates of high-load relay node B are (100, 100), the communication radius is 150m, and the surrounding nodes X, Y, and Z are located at (120, 130), (250, 240), and (90, 80) respectively. According to the two-dimensional Euclidean distance calculation formula, the distance between node X and B is determined to be... = = ≈36m, node Y distance is = = ≈205m, node Z distance is = = ≈22m, where the distance between nodes X and Z is less than the communication radius. If their status flags are both 0, then the numbers of X and Z are written into the set. Node Y is removed directly if its distance exceeds the communication radius and its status flag is 1. Finally, the set of free nodes within the communication radius is obtained.

[0032] S312: Based on the set of idle nodes within the communication radius, collect the continuous idle duration and corresponding signal forwarding success frequency of each node in the set during the current period, construct a ratio expression based on the idle duration and forwarding success frequency of each node, calculate the ratio result of each node, and store the ratio with the node number to obtain the idle forwarding ratio mapping structure. Read the node numbers from the set of idle nodes within the communication radius. Collect the idle time and successful forwarding count recorded for each node in the current period. The idle time is obtained from the time difference recorded by the node status flag, and the number of successful forwardings is obtained from the ACK response statistics of the channel acknowledgment signal. For example, node X has been idle for a cumulative time of 150 seconds and has 5 successful forwardings in the current period, while node Z has been idle for 180 seconds and has 4 successful forwardings. Construct an idle forwarding ratio expression for each node, defining the ratio as the ratio of idle time to the number of forwardings. That is, the ratio for node X is 150 / 5=30, and the ratio for node Z is 180 / 4=45. Establish a key-value pair structure between each ratio and the corresponding node number, and store them uniformly as a mapping structure. During the construction process, nodes with 0 successful forwardings need to be excluded to avoid division by zero errors. For example, if node W has 0 forwardings, it is skipped. The ratio structure is formed as {X: 30, Z: 45}, and finally the idle forwarding ratio mapping structure is obtained.

[0033] S313: Based on the idle forwarding ratio mapping structure, sort all ratio results in descending order of numerical value, extract the node number corresponding to the first item in the sorting result as the preferred target for the current relay role transfer, and output the corresponding node number to obtain the target node number for the relay role transfer. Based on the idle forwarding ratio mapping structure, a size comparison operation is performed on the ratio data items, and the values ​​are sorted in descending order. The sorted key-value pairs are arranged in descending order of ratio. For example, if the current structure is {Z: 45, X: 30}, then the sorting result is Z first and X last. The first item node number Z is extracted as the candidate node number for relay role transfer. At the same time, it is verified whether it meets the condition of not being a high-load node. If the verification is successful, the number is retained as the target output. If the verification fails, the process is moved to the next sorting item and the judgment process is re-executed. In this example, node Z is in an idle state and is not in the high-load warning list, which meets the requirements. Its number is recorded in the final list item, and finally the target node number for relay role transfer is obtained.

[0034] Table 3. Forwarding Capacity of Idle Nodes As shown in Table 3, node Z was identified as the relay role transfer target because its idle forwarding ratio was higher than that of other candidate nodes and it had idle availability.

[0035] Please see Figure 5 The specific steps of S4 are as follows: S411: Read the relay role transfer target node number, collect the path channel number parameters, synchronization clock configuration parameters and link index identification information associated with the node according to the local cache configuration content of the node number index, decompose the collected parameters into independent data, and generate the node cache parameter field set. The relay role transfer target node number is read. Taking node number Z as an example, the three configuration information items recorded in its local buffer are retrieved. First, the path channel number item is extracted. Assuming that the content of this item is {CH_01, CH_03, CH_07}, it represents the channel configuration of the current node in different directions. Next, the synchronization clock parameter field is located. This field records the offset value from the network master clock in microseconds. For example, the offset value is set to ±3μs. Then, the link index information is obtained. The link index is recorded in the form of index identifier + link type flag. For example, {L_01: uplink, L_02: downlink, L_03: uplink}, which points to the front-end terminal, the back-end terminal and the backup link device, respectively. After classifying and extracting the three types of information according to the field structure, they are written into the corresponding cache field set. A mapping relationship is established according to the number index. The node number Z corresponds to the field set {CH_01, CH_03, CH_07}, {+3μs} and {L_01, L_02, L_03}, respectively. Finally, the node cache parameter field set is generated.

[0036] S412: Based on the node cache parameter field set, the path channel number and link index identifier are combined and processed. According to the upstream and downstream device types and connection relationships marked by the link index identifier, the channel number corresponding allocation from the new relay node to the upstream and downstream devices is completed, and the point-to-point connection relationship structure between devices is constructed to obtain the relay node channel mapping structure. Based on the node cache parameter field set, the path channel number group {CH_01, CH_03, CH_07} and the link index group {L_01, L_02, L_03} are first read and mapped together. The corresponding upstream and downstream device relationships are determined according to the link direction type recorded in the link index identifier. CH_01 is defined to connect to upstream L_01, CH_03 to connect to downstream L_02, and CH_07 is a spare channel bound to L_03. Each pair of channel numbers is bound to the device index number according to the link direction to form a point-to-point connection structure, such as {Z→L_01: CH_01}, {Z→L_02: CH_03}, and {Z→L_03: CH_07}. Each pair of structures clearly indicates the channel resources allocated between the relay node and a specific device. If a channel number is missing or the link index is abnormal in a certain link direction during the combination process, the mapping item is removed and not written. The final result is organized into three sets of mapping pairs to obtain the relay node channel mapping structure.

[0037] S413: Based on the relay node channel mapping structure, aggregate the channel number, link direction, and synchronization clock offset parameters corresponding to each connection link, and classify all link items by node number and write them into the topology structure to establish a new relay path topology parameter set. Based on the three established channel link entries {Z→L_01:CH_01}, {Z→L_02:CH_03}, and {Z→L_03:CH_07} in the relay node channel mapping structure, the corresponding channel number, link direction, node number, and synchronization offset parameters are extracted for each group. The synchronization offset of node Z is set to +3μs. Topology parameter entries are constructed, with the entry structure being {node number, link target, direction type, channel number, synchronization offset}. For example, the first entry is {Z, L_01, uplink, CH_01, +3μs}, and the other two entries are filled in sequentially. All topology entries are summarized and written into the topology parameter set table. The table entries are archived uniformly with node number Z as the index key, and finally, a new relay path topology parameter set is established.

[0038] Table 4 New Relay Path Topology Parameters As shown in Table 4, node Z, as a new relay node, has completed the construction of its path topology, and the binding relationship between channel number, link direction and synchronization parameters has been clearly formed to form a structured topology configuration.

[0039] Please see Figure 6 The specific steps of S5 are as follows: S511: Based on the new relay path topology parameter set, extract the node number and link parameter information involved in each relay path, retrieve the corresponding wireless coverage layer according to the spatial coordinates of the path terminal node, match the grid cells in the area whose signal strength identification field is lower than the set standard value, mark the location as an indoor weak signal area, and establish the binding relationship between the number and the spatial index to generate a weak signal area location index table. Based on the node number, link direction, channel number, and synchronization offset recorded in the new relay path topology parameter set, the link terminal device number corresponding to each relay node is first extracted. Then, the node coordinate database registered in the node management system is called to retrieve the planar coordinate data of the terminal device in the indoor environment. A grid mapping operation is then performed on its position, using a grid partitioning mechanism with a coordinate density of 10 meters to map the device to a unique grid cell in the two-dimensional region. For example, if the downlink terminal device L_02 of node Z has coordinates (120, 85), it is mapped to the 13th row. For the 9th grid cell, the signal strength measurement results from the coverage assessment module are called. If the received power value is less than -90dBm, the area is determined to be a weak signal area; otherwise, it is marked as a normal signal area. All signal values ​​are extracted from the average value field of the actual measurement data frames within the period. When the signal strength is -92.5dBm, it meets the weak signal area determination criteria. Then, the corresponding relay path number is bound to the grid cell at that location, and the grid number, path number, and signal threshold information are recorded to complete the joint mapping between the location and the relay path parameters, and finally generate a weak signal area location index table.

[0040] S512: Based on the weak signal area location index table, match the spatial coordinates of each identified area with the path number configuration in the path resource pool, retrieve the connection status, and if the identified status is available, write the path number into the matching set to obtain a list of available path numbers in the area. Based on the weak signal area location index table, all grid numbers identified as weak signal areas are read sequentially. All path number configurations in the path resource pool are traversed, and the spatial coordinates of the terminal node of each path item are extracted. A coordinate matching operation is used to determine whether the path falls within the grid number of the weak signal area. For example, the terminal node coordinates of path P_07 are (120, 85), which fall into the grid cell numbered 13 rows and 9 columns, consistent with the weak signal area identified in paragraph 1. Therefore, path P_07 is added to the candidate path set. Then, the connection status field corresponding to the path is retrieved. If the field value is "1", the path is currently available; if it is "0", it is unavailable. Only path numbers with a connection status field value of "1" are retained. The filtered path numbers are written into the set. This process is repeated for all paths, generating a complete set structure composed of path numbers that meet both spatial location matching and connection status availability. Finally, a list of available path numbers within the region is obtained.

[0041] S513: Based on the list of available path numbers in the region, activate the connection status of each candidate path item, modify the path status to active status, mark and record the path numbers that have completed the activation process, aggregate the region number, path number and status flag information, and establish a relay coverage optimization record for weak signal areas. Based on the path number information in the list of available path numbers within the region, the record of each path item in the path status table is retrieved sequentially. The original connection status field is read, and its value is modified to the activation status code "2", indicating that the current path is activated. Then, the "status update timestamp" field of the corresponding record in the path status table is assigned the current system time to complete the status update process. After the status change is completed, a path activation record entry is created in the system log, and information fields such as path number, activation time, and area number are written. All successfully activated path numbers are counted, and their weak signal area location and binding node information are recorded. All record items are compiled and summarized into a coverage structure data table, with fields including area number, path number, channel number, status code, etc. The data table is output in a structured format, and finally, a relay coverage optimization record for weak signal areas is established.

[0042] Table 5. Record of Path Coverage Optimization in Weak Signal Areas As shown in Table 5, path P_07 is the path number activated in the available state. Its weak signal area and channel configuration are recorded together in the coverage optimization record for easy subsequent management and review.

[0043] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection of the described technical solutions.

Claims

1. A method for optimizing relay coverage in indoor weak signal areas based on D2D terminal collaboration, characterized in that, Includes the following steps: S1: Collect the D2D terminal node number information, collect all forwarding timestamps recorded by each D2D terminal node when it performs downlink signal forwarding in the current period, calculate the difference between adjacent forwarding timestamps of the same node as the forwarding interval of the node, establish the mapping relationship between each node number and the corresponding forwarding interval sequence, and output the node forwarding interval mapping structure. S2: Read the time series data in the node forwarding interval mapping structure, construct window groups based on every three consecutive periods, determine the downward trend of each window group, mark high-load relay nodes, and output a list of relay node load warnings; S3: Based on the relay node load warning list, filter out the D2D terminal nodes that are idle within the communication radius of each high-load relay node, filter out new relay nodes, and output the relay role transfer target node number. S4: Read the target node number of the relay role transfer, synchronously obtain the path channel number, synchronization clock parameters and link index information through the node local cache, establish the channel relationship mapping from the new relay node to the upstream and downstream devices, and output the new relay path topology parameter set; S5: Based on the new relay path topology parameter set, locate the corresponding indoor weak signal area, filter candidate path numbers that match the corresponding area, activate path items with available connection status, and output the weak signal area relay coverage optimization record.

2. The indoor weak signal area relay coverage optimization method based on D2D terminal collaboration according to claim 1, characterized in that: The high-load relay node specifically refers to the node that determines whether the forwarding interval of the window group has shown a decreasing trend twice in a row and counts the magnitude of the decrease. If the magnitude of the decrease exceeds the set forwarding offset threshold, the corresponding node number is marked as a high-load relay node.

3. The indoor weak signal area relay coverage optimization method based on D2D terminal collaboration according to claim 1, characterized in that: The new relay node specifically refers to the node whose idle time and signal forwarding success frequency are statistically analyzed within the current period of the idle D2D terminal node, the ratio of the two parameters is calculated and sorted, and the node number with the highest ranking is selected as the new relay node.

4. The indoor weak signal area relay coverage optimization method based on D2D terminal collaboration according to claim 1, characterized in that: The node forwarding interval mapping structure includes forwarding behavior pattern characteristics, node forwarding activity labels, and time series fluctuation indicators. The relay node load warning list includes high-load node numbers, load anomaly trend levels, and periodic forwarding density factors. The relay role transfer target node number includes target node identifier, availability performance ratio, and channel switching priority. The new relay path topology parameter set includes inter-node channel number index, synchronization clock offset parameters, and link connection direction labels. The weak signal area relay coverage optimization record includes optimized path number, area signal coverage level, and active path status marker.

5. The indoor weak signal area relay coverage optimization method based on D2D terminal collaboration according to claim 1, characterized in that, The steps for obtaining the node forwarding interval mapping structure are as follows: S111: Obtain all D2D terminal node number information, collect all downlink signal forwarding timestamps of each terminal node within a set period, calculate the difference between adjacent items in the timestamp sequence based on each node number, classify and store the calculated time difference according to the node number, and generate a node forwarding interval data sequence set. S112: Based on the node forwarding interval data sequence set, for each node's corresponding forwarding interval data sequence, detect whether there are abrupt changes in the time interval in the sequence. If so, perform interpolation completion processing based on adjacent valid interval values ​​to obtain the completed node forwarding interval sequence set. S113: Based on the completed node forwarding interval sequence set, construct a one-to-one correspondence structure between each node number and the corresponding forwarding interval sequence, aggregate all entries to form a unified structure, and obtain the node forwarding interval mapping structure.

6. The indoor weak signal area relay coverage optimization method based on D2D terminal collaboration according to claim 1, characterized in that, The steps for obtaining the relay node load warning list are as follows: S211: Read the forwarding interval sequence data in the node forwarding interval mapping structure, extract the time series according to each node number, divide each sequence into a continuous time window group with a length of three periods according to the time order, calculate the average value of all interval values ​​in each window group, and generate a node period mean sequence set. S212: Based on the node periodic mean sequence set, for the mean sequence corresponding to each node number, extract the mean values ​​of two adjacent window groups in chronological order to form a comparison pair, calculate the difference between the two mean values ​​in each comparison pair, and determine whether the difference value shows a downward trend. If the mean value of the latter group is less than the mean value of the former group in two consecutive comparisons and the decrease is greater than the set forwarding offset threshold, then mark the corresponding node number as a high-load relay node to obtain the overload node number set. S213: Based on the set of overload node numbers, establish a number index entry for each marked node number, aggregate all marked information into a unified data list structure, complete the sorting of all marked node information, and obtain the relay node load warning list.

7. The indoor weak signal area relay coverage optimization method based on D2D terminal collaboration according to claim 1, characterized in that, The steps for obtaining the target node number for relay role transfer are as follows: S311: Based on the node number information in the relay node load warning list, retrieve the communication radius range of each high-load relay node in the current period, detect the current status of all D2D terminal nodes within the range, filter out nodes that are in signal forwarding or in an occupied state, retain only the node numbers that are not participating in the forwarding task, and generate a set of idle nodes within the communication radius. S312: Based on the set of idle nodes within the communication radius, collect the continuous idle duration and corresponding signal forwarding success frequency of each node in the set in the current period, construct a ratio expression based on the idle duration and forwarding success frequency of each node, calculate the ratio result of each node, and store the ratio with the node number to obtain the idle forwarding ratio mapping structure. S313: According to the idle forwarding ratio mapping structure, sort all ratio results in descending order of numerical value, extract the node number corresponding to the first item in the sorting result as the preferred target for the current relay role transfer, and output the corresponding node number to obtain the target node number for the relay role transfer.

8. The indoor weak signal area relay coverage optimization method based on D2D terminal collaboration according to claim 1, characterized in that, The steps for obtaining the new relay path topology parameter set are as follows: S411: Read the target node number of the relay role transfer, collect the path channel number parameters, synchronization clock configuration parameters and link index identification information associated with the node according to the local cache configuration content of the node number index, decompose the collected parameters into independent data, and generate a node cache parameter field set. S412: Based on the node cache parameter field set, the path channel number and link index identifier are combined and processed. According to the upstream and downstream device types and connection relationships marked by the link index identifier, the channel number corresponding allocation from the new relay node to the upstream and downstream devices is completed, and the point-to-point connection relationship structure between devices is constructed to obtain the relay node channel mapping structure. S413: Based on the relay node channel mapping structure, aggregate the channel number, link direction, and synchronization clock offset parameters corresponding to each connection link, and classify all link items by node number and write them into the topology structure to establish a new relay path topology parameter set.

9. The indoor weak signal area relay coverage optimization method based on D2D terminal collaboration according to claim 1, characterized in that, The steps for obtaining relay coverage optimization records in the weak signal area are as follows: S511: Based on the new relay path topology parameter set, extract the node number and link parameter information involved in each relay path, retrieve the corresponding wireless coverage layer according to the spatial coordinates of the path terminal node, match the grid cell whose signal strength identification field is lower than the set standard value in the area, mark the location as an indoor weak signal area, and establish the binding relationship between the number and the spatial index to generate a weak signal area location index table. S512: Based on the weak signal area location index table, match the spatial coordinates of each identified area with the path number configuration in the path resource pool, retrieve the connection status, and if the identified status is available, write the path number into the matching set to obtain a list of available path numbers in the area. S513: Based on the list of available path numbers in the area, activate the connection status of each candidate path item, modify the path status to the active state, mark and record the path numbers that have completed the activation process, aggregate the area number, path number and status flag information, and establish a relay coverage optimization record for weak signal areas.

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