Wireless ad hoc network method based on WIFI

Abstract

The invention relates to the technical field of wireless communication, and discloses a wireless ad hoc network method based on WIFI (Wireless Fidelity), which comprises the following steps of: periodically broadcasting a WIFI beacon frame by utilizing each WIFI device, taking the WIFI beacon frame as a time anchor point, sending a multicast data frame along with the beacon frame to form a unique time slot unit, analyzing a timestamp in the beacon frame by each WIFI device, calculating and exchanging relative offsets of each other, and sending the multicast data frame to the wireless ad hoc network. The invention also introduces a received signal strength indicator (RSSI) bidirectional acknowledgement mechanism, ensures high-quality establishment of links of both communication parties, solves the trouble of single-pass, and improves the communication efficiency by intelligently adjusting the sending position of the own beacon frame, thereby adaptively avoiding a hidden node problem in a distributed environment, and remarkably improving the connectivity and stability of the network, and in addition, the invention also introduces a received signal strength indicator (RSSI) bidirectional acknowledgement mechanism to ensure high-quality establishment of links of both communication parties. Smooth and clear full-duplex voice communication is realized, and reliable and efficient experience is provided for emergency communication, team cooperation and other scenes.

Description

Technical Field

[0001] The present invention relates to a WIFI wireless ad-hoc network method, belonging to the technical field of wireless communication. Background Art

[0002] As a network form that enables direct communication between devices without the support of infrastructure, wireless ad-hoc networks have shown great potential in various scenarios such as emergency rescue, field operations, industrial collaboration, and home entertainment. Especially in full-duplex voice communication, it allows multiple users to have natural and smooth conversations simultaneously, greatly improving the efficiency of team collaboration and the timeliness of information transmission. However, in the prior art, there are usually many problems in implementing a full-duplex voice ad-hoc network. A common implementation method is to use traditional half-duplex walkie-talkies, such as devices based on very high frequency (VHF) or ultra-high frequency (UHF); such devices usually require users to press the push-to-talk (PTT) button to speak and can only receive after releasing it, unable to achieve a truly natural conversation. This push-to-talk mode brings significant inconvenience in multi-person collaborative communication. For example, when multiple users press the PTT button simultaneously, it is easy to cause signal conflicts, resulting in chaotic conversations and low information transmission efficiency; it is necessary to rely on manual coordination of the speaking order, which will seriously slow down the response speed and increase 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 to explore the adoption of full-duplex ad-hoc network voice communication solutions. Among them, time division multiple access (TDMA) technology is one of the current mainstream implementation methods. By dividing time into multiple available time slots, communication devices in the network can reuse time slot resources to achieve full-duplex communication. However, TDMA technology still has the following problems in practical applications: 1. The time slot allocation algorithm is complex. When using a centralized reservation time slot allocation algorithm, additional signaling overhead and time waiting are required, resulting in obvious latency problems; 2. The distributed time slot allocation algorithm is prone to conflicts. When multiple devices attempt to select time slots without central coordination, time slot conflicts will inevitably occur. Multiple devices may enter the same time slot, causing mutual interference, thus seriously affecting communication quality and stability. In addition, Bluetooth technology has also been tried to achieve full-duplex communication. Bluetooth technology uses time division duplex (TDD) communication technology and can theoretically achieve full-duplex voice transmission. However, Bluetooth technology is limited by its inherent bandwidth limitation, resulting in its inability to accommodate more user nodes and difficult to meet the requirements of large-scale ad-hoc networks. At the same time, Bluetooth is relatively backward in modulation mode, which also restricts its communication performance to a certain extent in complex environments.

[0004] The deficiencies of these existing technical solutions, especially the inherent delays and conflicts in time slot allocation of TDMA technology, as well as the limitations of Bluetooth technology in terms of bandwidth and user capacity, have made it an urgent technical problem to achieve stable, efficient and multi-user full-duplex voice communication in wireless ad-hoc networks. When facing challenges such as hidden nodes (i.e., some nodes in the network are not reachable to each other but communicate through intermediate nodes, resulting in potential conflicts) and asymmetric received signals (i.e., inconsistent two-way link quality leading to single-pass phenomenon), existing solutions often fail to provide ideal solutions, seriously affecting the reliability of communication and user experience. Summary of the Invention

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

[0006] To achieve the above object, a method for WIFI wireless ad-hoc network provided by the present invention includes: Each WIFI device periodically broadcasts a WIFI beacon frame, and the WIFI beacon frame carries the control information and current timestamp information of the WIFI device; Using the WIFI beacon frame as the time anchor for each WIFI device; Following the sending moment of the WIFI beacon frame, the multicast data frame sent by the WIFI device forms a time slot unit combined with the WIFI beacon frame; The WIFI device scans and receives the WIFI beacon frames broadcast by other WIFI devices, calculates the relative offset of other WIFI devices with respect to the WIFI beacon frame of the local WIFI device according to the timestamp information carried in the received WIFI beacon frame, and records the relative offset in the offset table maintained locally; The local WIFI device adjusts the sending position of its broadcast WIFI beacon frame to a time slot position different from the sending position of the WIFI beacon frame corresponding to other WIFI devices recorded in the offset table according to the offset table, and maintains a margin determined by the WIFI bandwidth and the maximum number of networked devices; The local WIFI device broadcasts the information of the offset table 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, through a confirmation operation, they maintain a consistent acceptance list and determine their respective device identification codes according to their positions in the acceptance list.

[0007] Preferably, following the transmission time of the WIFI beacon frame immediately with the multicast data frame further includes: the WIFI device designates a transmission anchor point for the multicast data frame, and the transmission anchor point is located at a determined delay position after the WIFI device's own WIFI beacon frame, so as to stagger the packet transmission times of each WIFI device in the wireless ad-hoc network.

[0008] Preferably, the transmission of the multicast data frame further includes: retransmitting the multicast data frame multiple times to improve the reception success rate; the multiple retransmissions are implemented by configuring the maximum beacon interval count and the maximum retransmission times, where the maximum beacon interval count is used to control the number of transmissions of the same media access control service data unit data on the time slot unit, and the maximum retransmission times is used to control the maximum number of retransmissions of a media access control protocol data unit data within a single time slot unit.

[0009] Preferably, before the WIFI device receives the multicast data frame sent by other WIFI devices, it further includes: when the WIFI device receives the multicast data frame sent by other WIFI devices, it obtains the received signal strength indication value of the multicast data frame; performs filtering processing on the received signal strength indication value, and the filtering processing adopts mean filtering or moving average filtering; when the filtered received signal strength indication value reaches the first strength threshold, the local WIFI device adds the other WIFI device to the device list maintained locally; and the local WIFI device broadcasts the device list information it maintains to other WIFI devices in the wireless ad-hoc network.

[0010] Preferably, the condition for the local WIFI device to communicate with other WIFI devices is: the local WIFI device has added the other WIFI device to the device list maintained locally; and the other WIFI device has added the local WIFI device to the device list it maintains locally, and the filtered received signal strength indication value of the other WIFI device receiving the signal sent by the local WIFI device reaches the preset second strength threshold.

[0011] Preferably, during the process of the WIFI device scanning and receiving the WIFI beacon frames broadcast by other WIFI devices, it further includes: when a reception link is established between the local WIFI device and other WIFI devices, the local WIFI device continuously receives the WIFI beacon frames sent by other WIFI devices multiple times and calculates the received signal strength indication value of the WIFI beacon frames; when the received signal strength indication values of the continuously received WIFI beacon frames are all within the preset strength range, the local WIFI device considers that the WIFI beacon frame synchronization with other WIFI devices has been completed.

[0012] Preferably, during the continuous communication of the WIFI device in the wireless ad-hoc network, it further includes: when the WIFI device does not receive the WIFI beacon frames sent by other WIFI devices continuously for multiple times within the set timer time, it determines that the receiving link corresponding to the other WIFI devices fails and disconnects; 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.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention organically combines the periodic broadcast characteristic of the WIFI beacon frame with the construction mechanism of the time slot unit, realizing a highly adaptive and distributed full-duplex voice communication architecture. By taking each WIFI beacon frame as the starting point of the time slot unit it constructs, and allowing each device to intelligently adjust the sending 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-adjustment ability provide an unprecedented smooth and stable experience for full-duplex real-time voice communication among multiple devices under the existing WIFI protocol framework. Especially in a dynamically changing wireless ad-hoc network environment, it effectively solves the delay problem caused by traditional centralized time slot allocation and the conflicts that may be caused by complex distributed algorithms, and realizes the optimal utilization of network resources and the stable and reliable communication in a simple and efficient way.

[0014] 2. By carrying and exchanging the relative offset information between devices in the WIFI beacon frame, and allowing each device to spontaneously and indirectly sense 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 frame. This seamless integration scheme based on the existing protocol signaling avoids introducing additional complex control signaling or consuming 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 the communication link. In complex scenarios such as emergency rescue and construction cooperation where the central base station cannot be relied on, users can enjoy more reliable and comprehensive voice coverage, greatly improving the efficiency and safety of team cooperation.

[0015] 3. Through the Received Signal Strength Indicator (RSSI) two-way confirmation mechanism, the present invention avoids the common single-pass problem in wireless ad-hoc networks, and realizes not only a simple judgment of the one-way link quality, but also requires both communication parties to confirm that the received signal strengths of each other reach a preset threshold, and broadcasts the information that the other party has joined the local device list to each other in the beacon frame to reach a consistent communication consensus. This two-way and mutually verified link quality determination strategy enables full-duplex communication to be established only when both ends of the link are in the best state, 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 tasks. In addition, in terms of the reliability of multicast data transmission, by flexibly configuring the maximum beacon interval count and the maximum number of retransmissions, the anti-interference ability and reception success rate of multicast voice data can be significantly improved on the premise of ensuring real-time performance. This refined retransmission strategy based on time slot units enables voice data to maintain high-quality transmission even when encountering wireless environment fluctuations, ensuring stable and uninterrupted clear calls provided by the full-duplex voice system under various working conditions. Brief Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the distributed time slot communication frame structure of the present invention.

[0017] Figure 2 It is a flow chart of the establishment of the distributed networking communication link of the present invention.

[0018] The implementation, functional features and advantages of the present invention will be further described in conjunction with the embodiments with reference to the drawings. Detailed Embodiments

[0019] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] The embodiments of the present application provide a method based on a WIFI wireless ad-hoc network, and the method includes: Each WIFI device periodically broadcasts a WIFI beacon frame, and the WIFI beacon frame carries the control information and the current timestamp information of the WIFI device; Use the WIFI beacon frame as the time anchor point of each WIFI device; The multicast data frame sent by the WIFI device is immediately after the sending moment of the WIFI beacon frame to form a time slot unit combined with the WIFI beacon frame and the multicast data frame; The WIFI device scans and receives the WIFI beacon frames broadcast by other WIFI devices, calculates the relative offset of other WIFI devices relative to the WIFI beacon frame of the local WIFI device according to the timestamp information carried in the received WIFI beacon frame, and records the relative offset in the offset table maintained locally; The local WIFI device adjusts the transmission position of its broadcast WIFI beacon frame to a time slot position different from that of the WIFI beacon frames corresponding to other WIFI devices recorded in the offset scale according to the offset scale, and maintains a margin determined by the WIFI bandwidth and the maximum number of networked devices; The local WIFI device broadcasts the offset scale 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, through a confirmation operation, they make the received lists they maintain consistent, and determine their respective device identification codes according to their positions in the received list.

[0021] Preferably, immediately following the transmission time of the WIFI beacon frame for the multicast data frame, it further includes: the WIFI device designates a transmission anchor point for the multicast data frame, and the transmission anchor point is at a determined delay position after the WIFI device's own WIFI beacon frame, so that the packet transmission times of each WIFI device in the wireless ad-hoc network are staggered from each other.

[0022] Preferably, the transmission of the multicast data frame further includes: retransmitting the multicast data frame multiple times to improve the reception success rate; the multiple retransmissions are implemented 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 transmissions of the same media access control service data unit data 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.

[0023] Preferably, before the WIFI device receives the multicast data frame sent by other WIFI devices, it further includes: when the WIFI device receives the multicast data frame sent by other WIFI devices, it obtains the received signal strength indication value of the multicast data frame; performs filtering processing on the received signal strength indication value, and the filtering processing uses mean filtering or moving average filtering; when the filtered received signal strength indication value reaches the first strength threshold, the local WIFI device adds the other WIFI device to the device list it maintains; and the local WIFI device broadcasts the device list information it maintains to other WIFI devices in the wireless ad-hoc network.

[0024] Preferably, the condition for mutual communication between the local WIFI device and other WIFI devices is: the local WIFI device has added the other WIFI device to the device list it maintains; and the other WIFI device has added the local WIFI device to the device list it maintains, and the filtered received signal strength indication value of the other WIFI device receiving the signal sent by the local WIFI device reaches a preset second strength threshold.

[0025] Preferably, during the process of the WIFI device scanning and receiving WIFI beacon frames broadcast by other WIFI devices, it further includes: after a receiving link is established between the local WIFI device and other WIFI devices, the local WIFI device continuously receives WIFI beacon frames sent by other WIFI devices multiple times and calculates the received signal strength indication value of the WIFI beacon frames; when the received signal strength indication values of the continuously received WIFI beacon frames are all within a preset strength range, the local WIFI device considers that the WIFI beacon frame synchronization with other WIFI devices has been completed.

[0026] Preferably, during the continuous communication process of the WIFI device in the wireless ad-hoc network, it further includes: when the WIFI device does not receive WIFI beacon frames sent by other WIFI devices continuously multiple times within the set timer time, it determines that the receiving link corresponding to other WIFI devices fails and disconnects; 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.

[0027] Embodiment 1: This embodiment elaborates in detail the specific implementation of a full-duplex voice communication method for a WIFI-based wireless ad-hoc network. In scenarios such as emergency rescue, when a team of multiple rescue workers 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 teamwork; in this scenario, each rescue worker wears a dedicated intercom device with a built-in WIFI communication module. After these intercom devices are powered on, they enter the ad-hoc network mode. The first stage: Periodic broadcast of beacon frames and establishment of time anchors. After each intercom device is powered on, its WIFI communication module automatically broadcasts WIFI beacon frames at a preset period (for example, every few milliseconds). Each WIFI beacon frame not only contains control information such as the unique identifier and current operating status of the device, but also carries high-precision current timestamp information. This periodically broadcast WIFI beacon frame serves as a stable heartbeat on the time axis for each device and acts as the time anchor for its local time slot scheduling; Formation of time slot units. Immediately after the sending moment of each WIFI beacon frame, the device sends a multicast data frame formed by the currently collected voice data within the time slot unit it constructs. This combination of beacon frame + multicast data frame constitutes the basic time slot unit exclusive to the device and can be used to carry full-duplex voice communication. In this way, each device can send voice data in an orderly manner under the guidance of its own beacon frame.

[0028] Second stage: Calculation and local maintenance of offsets. While continuously broadcasting their own beacon frames, each intercom device will also actively scan and receive the WIFI beacon frames broadcast by other surrounding intercom devices. Once a beacon frame from another device is received, the local device will immediately parse the timestamp information carried therein. Based on this timestamp and the local clock, the local device can accurately calculate the relative offset of the received beacon frame relative to the transmission time of its own beacon frame. 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 is the relative offset of this device.The relative offsets of all other detected devices are recorded in real time and maintained in an offset table of the local device; the adaptive synchronization of hidden nodes, which is an extremely crucial and innovative step. The local device will, based on the offset table it maintains, understand its visible neighbors and the hidden devices indirectly perceived through the neighbors. 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 there may be no direct communication between A and C, in order to avoid conflicts between its own beacon frame and the transmission time slots of any other known beacon frames in the network, the local device will intelligently adjust the transmission position of its WIFI beacon frame. For example, if it is found that the default transmission time of its own beacon frame is too close to the transmission time of a beacon frame of a remote device, which may cause interference, the local device will automatically fine-tune the transmission time of its beacon frame to an idle or least-interfering time slot position. This adjustment is not random but will ensure a margin jointly determined by the WIFI bandwidth and the maximum expected number of devices in the network with known beacon frames to guarantee sufficient communication intervals. In this way, even in the presence of hidden nodes, the network can achieve distributed and adaptive synchronization, thus avoiding potential conflicts in the time dimension and greatly enhancing the robustness of the network; the broadcast of offset information and network consistency. To ensure that the entire network has a unified understanding of the relative timing of each device, each intercom device will periodically broadcast the offset table information it locally maintains to other devices in the network through its own beacon frame or an 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 formation confirmation and device ID assignment. When the rescue team leader or any rescue personnel observes that the intercom device has discovered and displayed all expected team members, for example, after confirming the discovery of all X members through the device screen or voice prompt, he can initiate a network formation confirmation operation by pressing a confirmation button on the device. At this time, the device will sort the acceptance list it locally maintains, which contains the identifiers of all devices that have been discovered and confirmed to join the network, according to a preset rule, such as sorting by the device MAC address or serial number size, and broadcast the sorted list information to all devices in the network. All devices that receive this list will update their acceptance lists accordingly to ensure that the entire ad-hoc network maintains a unified member list. At the same time, each device will dynamically determine its own device identification code according to its position in this unified acceptance list. For example, the device ranked first in the list is device 1, and so on. This mechanism ensures the uniqueness and consistency of network member identities without central control.

[0029] Example 2: This example further elaborates in detail 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 problem of asymmetric received signals; First stage: After successfully establishing an ad-hoc network and completing device synchronization, each WIFI device encapsulates the periodically collected voice data into multicast data frames and sends them through its WIFI communication module. To maximize the transmission reliability of voice data, this example optimizes the transmission strategy of multicast data frames: Transmission anchor and time slot staggering mechanism. When each WIFI device sends its multicast data frame, it assigns a clear transmission anchor to its data frame. This transmission anchor is precisely defined at a certain delay position after the device's own WIFI beacon frame is sent. For example, after the beacon frame of device A is sent, it sends its multicast data after time, and after the beacon frame of device B is sent, it sends its multicast data after time. By pre-designing and coordinating the positions of these transmission anchors, it is ensured that within the same beacon cycle, the multicast data frames of different devices are staggered on the time axis, thus effectively avoiding time slot conflicts at the sending end and improving the utilization efficiency of air resources. This orderly transmission mechanism is the key guarantee for realizing multi-user full-duplex communication; Multi-dimensional retransmission strategy. Given that WIFI multicast essentially does not provide a link layer acknowledgment (ACK) mechanism, to improve the reception success rate and anti-interference ability of multicast data frames, this example adopts a two-level configurable retransmission strategy: Cross-beacon interval retransmission (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 cycles. For example, if the maximum beacon interval count is set to 3, an MSDU will be sent once within its corresponding time slot unit in each of the 3 consecutive beacon cycles after its transmission. This strategy makes the voice data more dispersed in time, effectively coping with instantaneous interference or deep fading in the wireless environment, thereby enhancing the overall anti-interference ability and improving the reception success rate; Retransmission within a single beacon interval (controlled by the maximum number of retransmissions). Within the time slot unit corresponding to a single beacon frame cycle, a media access control protocol data unit (MPDU), that is, the actual WIFI frame, can be repeatedly sent multiple times. For example, if the maximum number of retransmissions is set to 5, within a time slot unit, the same MPDU will be continuously sent 5 times. This fast and dense repeated transmission can utilize channel redundancy in a short time to further increase the probability that the MPDU is successfully captured by the receiving end. By flexibly configuring these two parameters, the system can find the best balance between transmission delay and anti-interference ability to meet the dual requirements of low delay and high reliability for full-duplex voice communication.

[0030] The second stage: Due to its inherent complexity and dynamics, wireless ad-hoc networks often face the one-way communication problem, that is, due to link asymmetry, one party can receive the signal of the other party, but the other party cannot receive the signal of this party 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 (RSSI). When each intercom device receives a multicast data frame sent by other devices, it will real-time acquire the RSSI value of this data frame. Since the RSSI value may have instantaneous fluctuations in the wireless environment, in order to obtain a more stable and real link quality assessment, this embodiment performs filtering processing on the acquired RSSI value. The filtering can adopt mean filtering or moving average filtering. For example, mean filtering can take the average of multiple sampled RSSI values within a set period, as shown in the formula: , where is the filtered RSSI value, is the number of sampling points, is the th sampling value. Moving average filtering smooths the data through weighted averaging, as shown in the formula: , where is the current filtering output, is the current input, is the previous filtering output, Let \(\alpha\) be the smoothing coefficient. These filtering methods effectively remove the instantaneous fluctuations of RSSI and provide a more stable link quality assessment; two-way link quality confirmation and communication establishment. The core of this embodiment lies in ensuring the two-way quality of communication. When the local intercom device receives the voice data of other devices and the filtered RSSI value reaches the preset first intensity threshold, the local device will consider the link quality in this direction to be good and add the other device to the device list maintained locally. 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 receiving the local device signal also reaches the preset second intensity threshold, only in this case of two-way confirmation and both directions meeting the intensity threshold, can these two devices be allowed to perform full-duplex voice communication with each other. This strict two-way quality verification mechanism fundamentally avoids the occurrence of the single-pass phenomenon and ensures that users can always conduct truly high-quality two-way intercom; reliable link management. In order to dynamically adapt to the movement and changes of the wireless ad-hoc network, this embodiment also designs a reliable link management mechanism. After the WIFI device scans the beacon frame of other devices, if it continuously receives its beacon frame multiple times and the RSSI value is always within the preset intensity range, it is considered that a reliable receiving link (RX link) has been successfully synchronized and established. On the contrary, if the beacon frame of a certain device fails to be received continuously multiple times within the set timer time, it is determined that the receiving link fails and is disconnected, and this information is reported to the network management layer so that the network can dynamically recalculate the communication path to ensure the self-healing ability and continuous connectivity of the network. All of these belong to the extended implementation methods known to those of ordinary skill in the art.

[0031] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A WIFI wireless ad-hoc network-based method, characterized in that, The method includes: Each WIFI device periodically broadcasts a WIFI beacon frame, and the WIFI beacon frame carries the control information and the current timestamp information of the WIFI device; Using the WIFI beacon frame as the time anchor for each WIFI device; Following the sending moment of the WIFI beacon frame with the multicast data frame sent by the WIFI device to form a time slot unit combined by a WIFI beacon frame and a multicast data frame; The WIFI device scans and receives the WIFI beacon frames broadcast by other WIFI devices, calculates the relative offset of other WIFI devices relative to the WIFI beacon frame of the local WIFI device according to the timestamp information carried in the received WIFI beacon frame, and records the relative offset in the offset measurement table maintained locally; The local WIFI device adjusts the sending position of the WIFI beacon frame broadcast by itself to a time slot position different from the sending position of the WIFI beacon frame corresponding to other WIFI devices recorded in the offset measurement table, and maintains a margin determined by the WIFI bandwidth and the maximum number of networked devices; The local WIFI device broadcasts the information of the offset measurement table maintained by it to other WIFI devices in the wireless ad-hoc network; and after the WIFI devices in the wireless ad-hoc network complete device discovery, through an acknowledgment operation, they maintain a consistent acceptance list and determine their respective device identification codes according to their positions in the acceptance list.

2. The method for WIFI wireless ad-hoc network according to claim 1, wherein, Following the sending moment of the WIFI beacon frame with the multicast data frame further includes: the WIFI device designates a sending anchor point for the multicast data frame, and the sending anchor point is at a determined delay position after the WIFI beacon frame of the WIFI device itself, so that the packet sending times of the WIFI devices in the wireless ad-hoc network are staggered from each other.

3. The WIFI wireless ad-hoc network-based method according to claim 1, wherein The sending of the multicast data frame further includes: retransmitting the multicast data frame multiple times to improve the reception success rate; the multiple retransmissions are implemented 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 data of the same media access control service data unit is sent on the time slot unit, and the maximum number of retransmissions is used to control the maximum number of retransmissions of the data of a media access control protocol data unit within a single time slot unit.

4. The method for WIFI wireless ad-hoc network according to claim 1, wherein Before the WIFI device receives the multicast data frame sent by other WIFI devices, it further includes: when the WIFI device receives the multicast data frame sent by other WIFI devices, it obtains the received signal strength indication value of the multicast data frame; performs filtering processing on the received signal strength indication value, and the filtering processing adopts mean filtering or moving average filtering; when the filtered received signal strength indication value reaches the first strength threshold, the local WIFI device adds the other WIFI device to the device list maintained locally; and the local WIFI device broadcasts the information of the device list maintained by it to other WIFI devices in the wireless ad-hoc network.

5. The method for WIFI wireless ad-hoc network according to claim 4, characterized in that, The condition for mutual communication between the local WIFI device and other WIFI devices is that the local WIFI device has added the other WIFI device to the device list maintained locally; Other WIFI devices have added the local WIFI device to the device list maintained locally by them, and the filtered received signal strength indication value of the signal sent by the local WIFI device received by the other WIFI devices reaches a preset second strength threshold.

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

7. The method for WIFI wireless ad-hoc network according to claim 1, wherein During the continuous communication process of the WIFI device in the wireless ad hoc network, it further includes: when the WIFI device does not receive the WIFI beacon frames sent by other WIFI devices continuously multiple times within the set timer time, it determines that the receiving link corresponding to the other WIFI device fails and disconnects; 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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