A wireless self-organizing network method based on WIFI

Abstract

The present invention relates to the field of wireless communication technology and discloses a WIFI-based wireless ad hoc network method. The method utilizes the periodic broadcasting of WIFI beacon frames by each WIFI device as a time anchor point, and transmits multicast data frames immediately following the beacon frames to form unique time slot units. Each WIFI device parses the timestamp in the beacon frame, calculates and exchanges relative offsets with each other, and intelligently adjusts the transmission position of its own beacon frame, thereby adaptively avoiding the hidden node problem in a distributed environment and significantly improving the connectivity and stability of the network. Furthermore, the present invention introduces a two-way confirmation mechanism using the received signal strength indicator (RSSI) to ensure high-quality link establishment between the communicating parties, resolve the problem of single-channel communication, and achieve smooth and clear full-duplex voice communication, providing a reliable and efficient experience for scenarios such as emergency communication and team collaboration.

Description

Technical Field

[0001] The invention relates to a WIFI-based wireless self-organizing network method, belonging to the technical field of wireless communications. Background Art

[0002] Wireless ad hoc networks, which enable direct communication between devices without infrastructure support, have shown great potential in a variety of scenarios, including emergency rescue, field operations, industrial collaboration, and home entertainment. In particular, full-duplex voice communication allows multiple users to engage in natural and smooth conversations simultaneously, significantly improving team collaboration efficiency and the timeliness of information transmission. However, existing technologies often face numerous challenges in implementing full-duplex voice ad hoc networks. One common approach is to use traditional half-duplex walkie-talkies, such as those based on very high frequency (VHF) or ultra-high frequency (UHF). These devices typically require users to hold down the PTT button to speak, and only receive after releasing it, preventing truly natural conversation. This push-to-talk mode presents significant inconveniences for collaborative multi-person communication. For example, when multiple users press the PTT button simultaneously, signal conflicts can easily occur, leading to confusion and inefficient information transmission. Furthermore, manual coordination of speaking order is required, which significantly slows response times and increases the risk of misjudgment in emergency or fast-paced collaborative scenarios.

[0003] To overcome the limitations of half-duplex walkie-talkies, the industry has begun exploring full-duplex voice communication solutions for ad hoc networks. Time Division Multiple Access (TDMA) technology is currently a mainstream implementation method. By dividing time into multiple available time slots, network devices can reuse time slot resources to achieve full-duplex communication. However, TDMA technology still faces the following challenges in practical applications: 1. The time slot allocation algorithm is complex. Using a centralized reserved time slot allocation algorithm requires additional signaling overhead and waiting time, resulting in significant latency. 2. The distributed time slot allocation algorithm is prone to conflicts. When multiple devices attempt to select time slots without central coordination, conflicts inevitably occur. Multiple devices may enter the same time slot, causing mutual interference and severely impacting communication quality and stability. Bluetooth technology has also been explored for full-duplex communication. Bluetooth uses time division duplex (TDD) communication technology, which theoretically can achieve full-duplex voice transmission. However, due to its inherent bandwidth limitations, Bluetooth cannot accommodate a large number of user nodes, making it difficult to meet the needs of large-scale ad hoc networks. At the same time, Bluetooth's modulation method is relatively backward, which also restricts its communication performance in complex environments to a certain extent.

[0004] The shortcomings of these existing technical solutions, especially the inherent delay and conflict issues in TDMA technology in time slot allocation, and the limitations of Bluetooth technology in bandwidth and user capacity, have made the implementation of stable, efficient, and multi-user full-duplex voice communication in wireless ad hoc networks a technical challenge that urgently needs to be solved. Existing solutions often fail to provide ideal solutions when faced with challenges such as hidden nodes (i.e., some nodes in the network are unreachable to each other but all communicate through intermediate nodes, leading to potential conflicts) and asymmetric received signals (i.e., inconsistent bidirectional link quality leading to single-channel phenomena), which seriously affects communication reliability and user experience. Summary of the Invention

[0005] The present invention provides a WIFI-based wireless ad hoc network method, the main purpose of which is to solve the problems of low efficiency, high delay, easy conflict, limited user capacity and insufficient reliability in complex environments.

[0006] To achieve the above object, the present invention provides a WIFI-based wireless ad hoc network method, the method comprising:

[0007] Each Wi-Fi device periodically broadcasts a Wi-Fi beacon frame, which carries the control information and current timestamp information of the Wi-Fi device;

[0008] Use Wi-Fi beacon frames as time anchor points for each Wi-Fi device;

[0009] The multicast data frame sent by the WIFI device is immediately after the sending time of the WIFI beacon frame, forming a time slot unit composed of the WIFI beacon frame and the multicast data frame;

[0010] The Wi-Fi device scans and receives Wi-Fi beacon frames broadcast by other Wi-Fi devices. Based on the timestamp information carried in the received Wi-Fi beacon frames, it calculates the relative offset of other Wi-Fi devices relative to the Wi-Fi beacon frame of the local Wi-Fi device and records the relative offset in the locally maintained offset table.

[0011] The local Wi-Fi device adjusts the sending position of the Wi-Fi beacon frame it broadcasts to a time slot position different from the sending position of the Wi-Fi beacon frame corresponding to other Wi-Fi devices recorded in the offset table according to the offset table, and maintains a margin determined by the Wi-Fi bandwidth and the maximum number of network members;

[0012] The local WIFI device broadcasts the offset table information it maintains to other WIFI devices in the wireless ad hoc network; and after the WIFI devices in the wireless ad hoc network complete device discovery, they maintain a consistent acceptance list through confirmation operations and determine their respective device identification codes based on their positions in the acceptance list.

[0013] Preferably, the multicast data frame is sent immediately after the sending time of the WIFI beacon frame, and further includes: the WIFI device specifies a sending anchor point for the multicast data frame, and the sending anchor point is located at a determined time delay position after the WIFI beacon frame of the WIFI device itself, so that the packet sending times of each WIFI device in the wireless ad hoc network are staggered.

[0014] Preferably, the sending of multicast data frames also includes: retransmitting the multicast data frames multiple times to improve the reception success rate; multiple retransmissions are achieved by configuring the maximum beacon interval count and the maximum number of retransmissions, wherein the maximum beacon interval count is used to control the number of times the same media access control service data unit data is sent on the time slot unit, and the maximum number of retransmissions is used to control the maximum number of retransmissions of a media access control protocol data unit data within a single time slot unit.

[0015] Preferably, before receiving the multicast data frame sent by other WIFI devices, the WIFI device further includes: when the WIFI device receives the multicast data frame sent by the other WIFI device, obtaining the received signal strength indication value of the multicast data frame; filtering the received signal strength indication value, and the filtering process adopts mean filtering or moving average filtering; when the filtered received signal strength indication value reaches a first strength threshold, the local WIFI device adds the other WIFI devices to the locally maintained device list; and the local WIFI device broadcasts the device list information it maintains to other WIFI devices in the wireless ad hoc network.

[0016] Preferably, the conditions for mutual communication between the local WIFI device and other WIFI devices are: the local WIFI device has added the other WIFI devices to a locally maintained device list; and the other WIFI devices have added the local WIFI device to their locally maintained device lists, and the filtered received signal strength indicator value of the signal sent by the local WIFI device received by the other WIFI devices reaches a preset second strength threshold.

[0017] Preferably, in the process of scanning and receiving WIFI beacon frames broadcast by other WIFI devices, the WIFI device further includes: after a receiving link is established between the local WIFI device and the other WIFI devices, the local WIFI device continuously receives WIFI beacon frames sent by other WIFI devices for multiple times, and calculates the received signal strength indication value of the WIFI beacon frame; when the received signal strength indication values ​​of the WIFI beacon frames received for multiple times are all within a preset strength range, the local WIFI device considers that WIFI beacon frame synchronization with the other WIFI devices has been completed.

[0018] Preferably, the process of continuous communication of the WIFI device in the wireless ad hoc network also includes: when the WIFI device fails to receive WIFI beacon frames sent by other WIFI devices for multiple consecutive times within the set timer time, it determines that the receiving links corresponding to the other WIFI devices are invalid and disconnected; and the WIFI device reports the information of the receiving link failure to the network management layer to recalculate the communication path in the wireless ad hoc network.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention organically integrates the periodic broadcast characteristics of WiFi beacon frames with the construction mechanism of time slot units to realize a highly adaptive and distributed full-duplex voice communication architecture. By using each WiFi beacon frame as the starting point of its own constructed time slot unit and allowing each device to intelligently adjust the transmission position of its own beacon frame based on the relative offset information in the received beacon frame to avoid potential time slot conflicts, this time slot construction and self-adaptation capability provides an unprecedented smooth and stable experience for full-duplex real-time voice communication between multiple devices within the existing WiFi protocol framework. Especially in the dynamically changing wireless ad hoc network environment, it effectively solves the delay problem caused by traditional centralized time slot allocation and the conflicts caused by complex distributed algorithms, achieving optimal utilization of network resources and stable and reliable communication in a minimalist and efficient manner.

[0021] 2. By carrying and exchanging relative offset information between devices in Wi-Fi beacon frames, and allowing each device to spontaneously and indirectly perceive and synchronize the existence of hidden nodes in the network based on this information, and then actively adjust the sending timing of its own beacon frames, this seamless integration solution based on existing protocol signaling avoids the introduction of additional complex control signaling or the consumption of a large amount of network resources, but can accurately solve the hidden node problem in a distributed environment, ensuring the integrity of the network topology and the availability of communication links. In complex sites such as emergency rescue and construction collaboration that cannot rely on central base stations, users can enjoy more reliable and comprehensive voice coverage, greatly improving the efficiency and security of team collaboration.

[0022] 3. This invention avoids the common single-channel issues in wireless ad hoc networks by utilizing a bidirectional confirmation mechanism based on the Received Signal Strength Indicator (RSSI). Rather than simply determining the quality of a one-way link, it requires both communicating parties to confirm that the received signal strength of each other has reached a preset threshold. The two parties then reach a consensus by broadcasting information in beacon frames that the other party has been added to the local device list. This bidirectional and mutually verified link quality determination strategy ensures that full-duplex communication is established only when both links are in optimal condition, significantly improving the clarity and fluency of voice communication. This ensures the accurate transmission of critical information in noisy and complex industrial sites or emergency missions. Furthermore, regarding the reliability of multicast data transmission, flexible configuration of the maximum beacon interval count and the maximum number of retransmissions significantly improves the anti-interference capability and reception success rate of multicast voice data while ensuring real-time performance. This refined retransmission strategy, based on time slot units, ensures that voice data maintains high-quality transmission even in fluctuating wireless environments, ensuring that the full-duplex voice system provides stable and clear calls under various operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the distributed time slot communication frame structure of the present invention.

[0024] Figure 2 A flow chart for establishing a distributed networking communication link of the present invention.

[0025] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0026] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] The present invention provides a method for wireless ad hoc networking based on WIFI, the method comprising:

[0028] Each Wi-Fi device periodically broadcasts a Wi-Fi beacon frame, which carries the control information and current timestamp information of the Wi-Fi device;

[0029] Use Wi-Fi beacon frames as time anchor points for each Wi-Fi device;

[0030] The multicast data frame sent by the WIFI device is immediately after the sending time of the WIFI beacon frame, forming a time slot unit composed of the WIFI beacon frame and the multicast data frame;

[0031] The Wi-Fi device scans and receives Wi-Fi beacon frames broadcast by other Wi-Fi devices. Based on the timestamp information carried in the received Wi-Fi beacon frames, it calculates the relative offset of other Wi-Fi devices relative to the Wi-Fi beacon frame of the local Wi-Fi device and records the relative offset in the locally maintained offset table.

[0032] The local Wi-Fi device adjusts the sending position of the Wi-Fi beacon frame it broadcasts to a time slot position different from the sending position of the Wi-Fi beacon frame corresponding to other Wi-Fi devices recorded in the offset table according to the offset table, and maintains a margin determined by the Wi-Fi bandwidth and the maximum number of network members;

[0033] The local WIFI device broadcasts the offset table information it maintains to other WIFI devices in the wireless ad hoc network; and after the WIFI devices in the wireless ad hoc network complete device discovery, they maintain a consistent acceptance list through confirmation operations and determine their respective device identification codes based on their positions in the acceptance list.

[0034] Preferably, the multicast data frame is sent immediately after the sending time of the WIFI beacon frame, and further includes: the WIFI device specifies a sending anchor point for the multicast data frame, and the sending anchor point is located at a determined time delay position after the WIFI beacon frame of the WIFI device itself, so that the packet sending times of each WIFI device in the wireless ad hoc network are staggered.

[0035] Preferably, the sending of multicast data frames also includes: retransmitting the multicast data frames multiple times to improve the reception success rate; multiple retransmissions are achieved by configuring the maximum beacon interval count and the maximum number of retransmissions, wherein the maximum beacon interval count is used to control the number of times the same media access control service data unit data is sent on the time slot unit, and the maximum number of retransmissions is used to control the maximum number of retransmissions of a media access control protocol data unit data within a single time slot unit.

[0036] Preferably, before receiving the multicast data frame sent by other WIFI devices, the WIFI device further includes: when the WIFI device receives the multicast data frame sent by the other WIFI device, obtaining the received signal strength indication value of the multicast data frame; filtering the received signal strength indication value, and the filtering process adopts mean filtering or moving average filtering; when the filtered received signal strength indication value reaches a first strength threshold, the local WIFI device adds the other WIFI devices to the locally maintained device list; and the local WIFI device broadcasts the device list information it maintains to other WIFI devices in the wireless ad hoc network.

[0037] Preferably, the conditions for mutual communication between the local WIFI device and other WIFI devices are: the local WIFI device has added the other WIFI devices to a locally maintained device list; and the other WIFI devices have added the local WIFI device to their locally maintained device lists, and the filtered received signal strength indicator value of the signal sent by the local WIFI device received by the other WIFI devices reaches a preset second strength threshold.

[0038] Preferably, in the process of scanning and receiving WIFI beacon frames broadcast by other WIFI devices, the WIFI device further includes: after a receiving link is established between the local WIFI device and the other WIFI devices, the local WIFI device continuously receives WIFI beacon frames sent by other WIFI devices for multiple times, and calculates the received signal strength indication value of the WIFI beacon frame; when the received signal strength indication values ​​of the WIFI beacon frames received for multiple times are all within a preset strength range, the local WIFI device considers that WIFI beacon frame synchronization with the other WIFI devices has been completed.

[0039] Preferably, the process of continuous communication of the WIFI device in the wireless ad hoc network also includes: when the WIFI device fails to receive WIFI beacon frames sent by other WIFI devices for multiple consecutive times within the set timer time, it determines that the receiving links corresponding to the other WIFI devices are invalid and disconnected; and the WIFI device reports the information of the receiving link failure to the network management layer to recalculate the communication path in the wireless ad hoc network.

[0040] Example 1: This example describes in detail the specific implementation of a full-duplex voice communication method for a wireless ad hoc network based on WIFI. For example, in an emergency rescue scenario, a team of multiple rescuers enters an area with poor signal coverage and needs to establish an ad hoc network that can support natural and smooth voice intercom to achieve real-time and efficient team collaboration. In this scenario, each rescuer wears a dedicated intercom device with a built-in WIFI communication module. After these intercom devices are started, they enter the ad hoc network mode. Phase 1: Periodic broadcast of beacon frames and establishment of time anchors. After each intercom device is powered on, its Wi-Fi communication module automatically broadcasts Wi-Fi beacon frames at a preset period (e.g., every few milliseconds). Each Wi-Fi beacon frame contains not only the device's unique identifier, current operating status, and other control information, but also a highly precise timestamp. For each device, these periodically broadcast Wi-Fi beacon frames act as a stable heartbeat on the timeline, serving as a time anchor for its local time slot scheduling. Following the transmission of each Wi-Fi beacon frame, the device then transmits a multicast data frame containing the currently collected voice data within the constructed time slot. This combination of beacon frames and multicast data frames constitutes a basic time slot unit dedicated to the device and can be used to carry full-duplex voice communication. In this way, each device can transmit voice data in an orderly manner, guided by its own beacon frames.

[0041] Phase 2: Offset calculation and local maintenance. While each intercom device continues to broadcast its own beacon frame, it will also actively scan and receive Wi-Fi beacon frames broadcast by other intercom devices around it. Once a beacon frame from another device is received, the local device will immediately parse the timestamp information carried in it. Based on the timestamp and the local clock, the local device can accurately calculate the relative offset of the received beacon frame relative to the time when its own beacon frame was sent. For example, if the local device sends a beacon frame at time T1 and receives a beacon frame sent by another device at time T2, then the difference between T2 and T1 or its position in the preset cycle period is the relative offset of the device.The relative offsets of all detected other devices will be recorded in real time and maintained in an offset table of the local device; adaptive synchronization of hidden nodes is an extremely critical and innovative step. The local device will understand its visible neighbors and the hidden devices indirectly perceived by the neighbors based on the offset table it maintains. For example, device A learns about the existence of device C and the relative position of its beacon frame through the beacon frame of device B. Although the beacon frame transmission timing between A and C may not be directly communicated, in order to avoid the conflict between its own beacon frame and the transmission time slot of any other known beacon frame in the network, the local device will intelligently adjust the transmission position of its own WIFI beacon frame. For example, If it is found that the default sending time of its own beacon frame is too close to the beacon frame sending time of a remote device, which may cause mutual interference, the local device will automatically fine-tune its own beacon frame sending time to an idle or minimally interfered time slot. This adjustment is not random, but will ensure that there is a margin between the known beacon frame and the Wi-Fi bandwidth and the maximum expected number of devices in the network to ensure sufficient communication interval. In this way, even if there are hidden nodes, the network can achieve distributed and adaptive synchronization, thereby avoiding potential conflicts in the time dimension and greatly improving the robustness of the network; the broadcast of offset information and network consistency are important to ensure the consistency of the entire network. The network has a unified understanding of the relative timing of each device. Each intercom device will periodically broadcast its locally maintained offset table information to other devices in the network through its own beacon frame or independent control frame. In this way, all devices can gradually build a global understanding of the relative timing of each device in the entire network, although this understanding is decentralized and dynamically updated; Network confirmation and device ID allocation, when the rescue team leader or any rescuer observes that the intercom device has discovered and displayed all expected team members, for example, after confirming that all X members have been discovered through the device screen or voice prompt, he can initiate the network confirmation operation by pressing a confirmation button on the device. , the device will sort its locally maintained acceptance list, which contains the identifiers of all devices that have been discovered and confirmed to join the network, according to preset rules, for example, by device MAC address or serial number size, and broadcast the sorted list information to all devices in the network. All devices that receive the list will update their own acceptance list accordingly, ensuring that the entire self-organizing network maintains a unified member list. At the same time, each device will dynamically determine its own device identification code based on its position in this unified acceptance list. For example, the first device in the list is device 1, and so on. This mechanism ensures the uniqueness and consistency of network membership under decentralized control.

[0042] Example 2: This example further elaborates on the optimization of data transmission reliability for full-duplex voice communication in a wireless ad hoc network and the adaptive solution mechanism for the asymmetric problem of received signals; Phase 1: After successfully establishing the ad hoc network and completing device synchronization, each WIFI device encapsulates the periodically collected voice data into a multicast data frame and sends it through its WIFI communication module. In order to maximize the transmission reliability of voice data, this example optimizes the sending strategy of the multicast data frame: the sending anchor point and time slot staggering mechanism. When each WIFI device sends its multicast data frame, it will specify a clear sending anchor point for its data frame. This sending anchor point is precisely defined at a certain time delay position after the device's own WIFI beacon frame is sent. For example, after the beacon frame of device A is sent, Time to send its multicast data, after device B sends the beacon frame By pre-designing and coordinating the positions of these sending anchor points, it is ensured that within the same beacon period, the multicast data frames of different devices are staggered on the time axis, thereby effectively avoiding time slot conflicts at the sending end and improving the utilization efficiency of air resources. This orderly sending mechanism is the key guarantee for achieving multi-user full-duplex communication; multi-dimensional retransmission strategy. Given that WIFI multicast does not essentially provide a link layer confirmation (ACK) mechanism, in order to improve the reception success rate and anti-interference ability of multicast data frames, this embodiment adopts a two-level configurable retransmission strategy: retransmission across beacon intervals (controlled by the maximum beacon interval count). A media access control service data unit (MSDU), that is, a complete voice data packet, may need to be repeatedly sent within multiple consecutive beacon frame periods. For example, if the maximum beacon interval count is set to 3, an MSDU will be retransmitted in each of the three consecutive beacon periods after it is sent. The voice data is transmitted once within the corresponding time slot unit. This strategy makes the voice data more dispersed in time, effectively coping with instantaneous interference or deep fading in the wireless environment, thereby enhancing overall anti-interference capabilities and improving the reception success rate. Retransmission within a single beacon interval (controlled by the maximum number of retransmissions) means that in the time slot unit corresponding to a single beacon frame period, a media access control protocol data unit (MPDU), that is, the actual WiFi frame, can be repeatedly transmitted multiple times. For example, if the maximum number of retransmissions is set to 5, the same MPDU will be sent five times in a row within a time slot unit. This rapid and intensive retransmission can exploit channel redundancy in a short period of time, further increasing the probability of the MPDU being successfully captured by the receiver. By flexibly configuring these two parameters, the system can find the optimal balance between transmission delay and anti-interference capabilities to meet the dual requirements of low latency and high reliability for full-duplex voice communication.

[0043] Phase 2: Due to its inherent complexity and dynamics, wireless ad hoc networks often face the one-way problem. That is, due to link asymmetry, one party can receive the other party's signal, but the other party cannot receive its own signal or the reception quality is extremely poor, resulting in the inability to achieve true two-way intercom. This embodiment cleverly solves this problem through the following mechanism: real-time acquisition and filtering of the received signal strength indicator value (RSSI). When each intercom device receives a multicast data frame sent by other devices, it will obtain the received signal strength indicator value of the data frame in real time. Since the RSSI value may have instantaneous fluctuations in the wireless environment, in order to obtain a more stable and realistic link quality assessment, this embodiment filters the obtained RSSI value. The filtering can use mean filtering or moving average filtering. For example, mean filtering can average multiple sampled RSSI values ​​within a set period, as shown in the formula: ,in is the RSSI value after filtering, is the number of sampling points, For the The moving average filter smoothes the data by weighted average, as shown in the formula: ,in is the current filter output, is the current input, is the previous filter output, For smoothing coefficients, these filtering methods effectively remove instantaneous fluctuations in RSSI and provide a more stable link quality assessment; two-way link quality confirmation and communication establishment, the core of this embodiment is to ensure the two-way quality of communication. When the local intercom device receives voice data from other devices and the filtered RSSI value reaches the preset first strength threshold, the local device will consider the link quality in this direction to be good and add the other device to the locally maintained device list. More importantly, the local device will broadcast the information that it has added the other party to the device list through its own WIFI beacon frame. When the other device receives this broadcast and finds that the local device has also added it to the device list, and at the same time, the filtered RSSI value of the other device's signal received by the local device also reaches the preset second strength threshold, only in the case of such two-way confirmation and the two-way satisfaction of the strength threshold, the two devices will be connected. Mutual full-duplex voice communication is allowed. This strict two-way quality verification mechanism fundamentally avoids the occurrence of single-channel phenomena and ensures that users can always conduct truly high-quality two-way intercoms. Reliable link management. In order to dynamically adapt to the movement and changes of wireless ad hoc networks, this embodiment also designs a reliable link management mechanism. After scanning the beacon frames of other devices, if the WIFI device receives its beacon frames multiple times in a row and the RSSI value is always within the preset strength range, it is considered that synchronization is successful and a reliable receiving link (RX link) is established. Conversely, if the beacon frame of a device is not received multiple times in a row within the set timer, the receiving link is determined to be invalid and disconnected, and this information is reported to the network management layer so that the network can dynamically recalculate the communication path to ensure the network's self-healing capability and continuous connectivity. These are all extended implementation methods known to ordinary technicians in this field.

[0044] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A WIFI-based wireless ad hoc network method, characterized in that: The method comprises: Each Wi-Fi device periodically broadcasts a Wi-Fi beacon frame, which carries the control information and current timestamp information of the Wi-Fi device; Use Wi-Fi beacon frames as time anchor points for each Wi-Fi device; The multicast data frame sent by the WIFI device is immediately after the sending time of the WIFI beacon frame, forming a time slot unit composed of the WIFI beacon frame and the multicast data frame; The Wi-Fi device scans and receives Wi-Fi beacon frames broadcast by other Wi-Fi devices. Based on the timestamp information carried in the received Wi-Fi beacon frames, it calculates the relative offset of other Wi-Fi devices relative to the Wi-Fi beacon frame of the local Wi-Fi device and records the relative offset in the locally maintained offset table. The local Wi-Fi device adjusts the sending position of the Wi-Fi beacon frame it broadcasts to a time slot position different from the sending position of the Wi-Fi beacon frame corresponding to other Wi-Fi devices recorded in the offset table according to the offset table, and maintains a margin determined by the Wi-Fi bandwidth and the maximum number of network members; The local WIFI device broadcasts the offset table information it maintains to other WIFI devices in the wireless ad hoc network; and after the WIFI devices in the wireless ad hoc network complete device discovery, they maintain a consistent acceptance list through confirmation operations and determine their respective device identification codes based on their positions in the acceptance list.

2. The WIFI-based wireless ad hoc network method according to claim 1, characterized in that: The multicast data frame is sent immediately after the sending time of the WIFI beacon frame, and further includes: the WIFI device specifies a sending anchor point for the multicast data frame, and the sending anchor point is located at a certain time delay position after the WIFI beacon frame of the WIFI device itself, so that the packet sending times of each WIFI device in the wireless ad hoc network are staggered.

3. The WIFI-based wireless ad hoc network method according to claim 1, characterized in that: The transmission of multicast data frames also includes: multiple retransmissions of multicast data frames to improve the reception success rate; multiple retransmissions are achieved by configuring the maximum beacon interval count and the maximum number of retransmissions, where the maximum beacon interval count is used to control the number of times the same media access control service data unit data is sent on a time slot unit, and the maximum number of retransmissions is used to control the maximum number of retransmissions of a media access control protocol data unit data within a single time slot unit.

4. The WIFI-based wireless ad hoc network method according to claim 1, characterized in that: Before receiving the multicast data frame sent by the other WIFI device, the WIFI device also includes: when the WIFI device receives the multicast data frame sent by the other WIFI device, obtaining the received signal strength indicator value of the multicast data frame; filtering the received signal strength indicator value, and the filtering process adopts mean filtering or moving average filtering; when the filtered received signal strength indicator value reaches a first strength threshold, the local WIFI device adds the other WIFI device to the locally maintained device list; and the local WIFI device broadcasts the device list information maintained by it to other WIFI devices in the wireless ad hoc network.

5. The WIFI-based wireless ad hoc network method according to claim 4, characterized in that: The condition for the local WIFI device to communicate with other WIFI devices is that the local WIFI device has added other WIFI devices to the locally maintained device list; The other WIFI devices have added the local WIFI device to their locally maintained device lists, and the filtered received signal strength indicator values ​​of the signals sent by the local WIFI device received by the other WIFI devices reach a preset second strength threshold.

6. The WIFI-based wireless ad hoc network method according to claim 1, characterized in that: The process of the WIFI device scanning and receiving the WIFI beacon frames broadcast by other WIFI devices also includes: after a receiving link is established between the local WIFI device and the other WIFI devices, the local WIFI device continuously receives the WIFI beacon frames sent by the other WIFI devices for multiple times and calculates the received signal strength indicator value of the WIFI beacon frame; when the received signal strength indicator values ​​of the WIFI beacon frames received for multiple times are all within a preset strength range, the local WIFI device considers that the WIFI beacon frame synchronization with the other WIFI devices has been completed.

7. The WIFI-based wireless ad hoc network method according to claim 1, characterized in that: The process of continuous communication of a WIFI device in a wireless ad hoc network also includes: when the WIFI device fails to receive WIFI beacon frames sent by other WIFI devices for multiple consecutive times within the set timer time, it determines that the receiving links corresponding to the other WIFI devices are invalid and disconnected; and the WIFI device reports the information of the receiving link failure to the network management layer to recalculate the communication path in the wireless ad hoc network.

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