Mapping method of wi-fi signal burst and mac layer protocol data unit

Abstract

The application discloses a kind of mapping method of WiFi signal burst and MAC layer protocol data unit, including obtaining input WiFi signal stream;The signal stream obtained is detected to burst signal;According to the detection result, a stream label is created for burst position;According to stream label, output data is updated and bound stream label;According to stream label, symbol mapping in WiFi signal processing process is completed by MAC layer protocol data unit decoding algorithm, and the mapping relationship of WiFi signal burst and MAC layer protocol data unit is established.The application detects and marks signal burst, so as to form the corresponding relationship between signal burst and MAC address after final protocol analysis;The application method can assist network administrator to lock the source equipment MAC address of illegal signal according to mapping table, and can also provide signal sample with label to construct data set;Moreover, the application has high reliability, good accuracy and stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of communication, and particularly relates to a mapping method of WiFi signal burst and MAC layer protocol data unit. BACKGROUND

[0002] Wideband wireless network is a hot spot in the development of communication industry. WLAN (Wireless Local Area Network) is one of the most scientific WLAN network connection methods at present. Due to the broadcast characteristics of wireless transmission, WLAN network is vulnerable to various attacks; in order to solve the security problem of WLAN network, an effective access management mechanism needs to be adopted.

[0003] Radio frequency fingerprinting technology has been used as an additional security enhancement technology for wireless devices to avoid spoofing or impersonation attacks. Radio frequency fingerprinting technology based on deep learning has shown great potential in the access management control of wireless devices. When the network administrator detects an illegal signal through radio frequency fingerprinting technology, the MAC address and other information of the illegal signal need to be obtained to take corresponding blocking and other restriction measures on the source device of the signal; therefore, the mapping relationship between WiFi signal burst and MAC address needs to be established.

[0004] However, the current technical scheme for establishing the mapping relationship between WiFi signal burst and MAC address has low reliability and poor accuracy. SUMMARY

[0005] The application aims to provide a mapping method of WiFi signal burst and MAC layer protocol data unit, which has high reliability, good accuracy and is stable and reliable.

[0006] The mapping method of WiFi signal burst and MAC layer protocol data unit provided by the application comprises the following steps:

[0007] S1. obtaining an input WiFi signal stream;

[0008] S2. detecting the burst signal of the obtained signal stream;

[0009] S3. creating a flow tag for the burst position according to the detection result obtained in step S2;

[0010] S4. updating and binding the flow tag for the output data according to the flow tag obtained in step S3;

[0011] S5. completing the symbol mapping in the WiFi signal processing process through the MAC layer protocol data unit decoding algorithm according to the obtained flow tag, and establishing the mapping relationship between WiFi signal burst and MAC layer protocol data unit.

[0012] The step S2 detects the acquired signal stream, and specifically includes the following steps:

[0013] The burst signal detection method acquires the start position and the end position of the complete signal burst in the signal stream, and records the absolute index value X1 of the start position of the detected burst signal in the data stream and the absolute index value X2 of the end position of the burst signal in the data stream.

[0014] The step S3 creates a stream tag for the burst position according to the detection result obtained in the step S2, and specifically includes the following steps:

[0015] The stream tag is created by using a stream tag creation interface in the GNU Radio framework;

[0016] The parameters of the stream tag include an output port, a bias, and a value: the output port is used to indicate the destination module of the stream tag transmission, and the parameter of the output port is set as the index of the corresponding output end; the bias is used to indicate the absolute index value of the tag position, and is set as the recorded start position of the signal burst; the value is used to record the absolute index value X1 of the start position of the signal burst in the data stream and the absolute index value X2 of the end position of the burst signal in the data stream, and is set as [X1, X2].

[0017] The step S4 updates and binds the stream tag for the output data according to the stream tag obtained in the step S3, and specifically includes the following steps:

[0018] When the complete WiFi signal burst passes through the subsequent module, the specific signal part in the physical frame is removed; at this time, the stream tag obtained in the step S3 is updated and bound at the output end: the absolute index value X3 of the corresponding data in the signal stream is acquired by using the interface provided by the GNU Radio framework in the remaining part of the output signal after being truncated, the bias parameter of the stream tag is updated as X3, and the value of the stream tag is kept unchanged; finally, the stream tag is bound with the data, so that the correspondence between the tag and the processed signal burst is ensured.

[0019] The step S5 completes the symbol mapping in the WiFi signal processing process by using a MAC layer protocol data unit decoding algorithm according to the obtained stream tag, and specifically includes the following steps:

[0020] The data stream and the stream label are acquired, the symbol mapping step in the WiFi signal processing process is completed through a MAC layer protocol data unit decoding algorithm, and a complete MAC layer protocol data unit is obtained; the value [X1, X2] of the stream label and the MAC PDU are transmitted to a MAC address analysis module through a message passing mechanism, and the decoding of the MAC PDU is completed in the module; once the analyzed MAC address MAC1 is output by the MAC address analysis module, the value [X1, X2] in the stream label and the MAC1 form a matching data pair and are stored, and the mapping of the signal burst and the MAC address is completed.

[0021] The WiFi signal burst and MAC layer protocol data unit mapping method provided by the application can be applied to the access management control system of a wireless device, and can assist a network administrator in locking the MAC address of a source device of an illegal signal according to a mapping table; meanwhile, the method can provide a signal sample with a label in a device identification application based on radio frequency signal deep learning, and construct a data set; and the method has high reliability, good accuracy and stability. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a method flowchart of the application.

[0023] Figure 2 The figure is a waveform diagram of the signal to be detected in the application.

[0024] Figure 3 The figure is a simulation signal time domain waveform diagram of the embodiment of the application.

[0025] Figure 4 The figure is an output signal flow diagram of the signal detection module of the embodiment of the application.

[0026] Figure 5 The figure is a signal burst position and MAC address matching data pair diagram of the embodiment of the application. DETAILED DESCRIPTION

[0027] As shown in the figure, the method flowchart of the application is as follows: the WiFi signal burst and MAC layer protocol data unit mapping method provided by the application comprises the following steps: Figure 1

[0028] S1. acquiring an input WiFi signal stream;

[0029] S2. detecting a burst signal from the acquired signal stream; specifically comprising the following steps:

[0030] As shown in the figure, the method flowchart of the application is as follows: the WiFi signal burst and MAC layer protocol data unit mapping method provided by the application comprises the following steps: Figure 2 ​As shown, the starting position and the ending position of the complete signal burst in the signal stream are obtained by burst signal detection methods such as calculation of the modulus square sum and autocorrelation characteristics, and the absolute index value X1 of the detected starting position of the burst signal in the data stream and the absolute index value X2 of the ending position of the burst signal in the data stream are recorded;

[0031] S3. A stream tag is created for the burst position according to the detection result obtained in step S2; specifically including the following steps:

[0032] A stream tag is created using the stream tag creation interface in the GNU Radio framework; the structure is shown in Table 1:

[0033] Table 1 Stream tag indication table

[0034]

[0035] The parameters of the stream tag include an output port, a bias, and a value: the output port is used to indicate the destination module of the stream tag transmission, and the parameter of the output port is set to the index of the corresponding output end; the bias is used to indicate the absolute index value of the tag position, and is set to the recorded starting position of the signal burst; the value is used to record the absolute index value X1 of the starting position of the signal burst in the data stream and the absolute index value X2 of the ending position of the burst signal in the data stream, and the value is set to [X1, X2];

[0036] S4. The stream tag is updated and bound to the output data according to the stream tag obtained in step S3; specifically including the following steps:

[0037] When the complete WiFi signal burst passes through the subsequent module, the specific signal part (such as the frame header, the guard interval, etc.) in a physical frame is removed; at this time, the stream tag obtained in step S3 is updated and bound to the output end: the absolute index value X3 of the corresponding data in the signal stream is obtained using the interface provided by the GNU Radio framework (typically, such as calling the function nitems-written()) in the remaining part of the output signal after being truncated, and the bias parameter of the stream tag is updated to X3, and the value of the stream tag is kept unchanged; finally, the stream tag is bound to the data, ensuring the correspondence between the tag and the processed signal burst;

[0038] S5. According to the obtained stream tag, the symbol mapping in the WiFi signal processing process is completed through the MAC layer protocol data unit decoding algorithm, and the mapping relationship between the WiFi signal burst and the MAC layer protocol data unit is established; specifically including the following steps:

[0039] The data stream and the stream label are acquired, the symbol mapping step in the WiFi signal processing procedure is completed through the MAC layer protocol data unit decoding algorithm, and a complete MAC layer protocol data unit is obtained; the value [X1, X2] of the stream label and the MAC PDU are transmitted to the MAC address analysis module through the message transmission mechanism, and the decoding of the MAC PDU is completed in the module; once the analyzed MAC address MAC1 is output by the MAC address analysis module, the value [X1, X2] in the stream label and the MAC1 form a matching data pair and are stored, and the mapping of the signal burst and the MAC address is completed.

[0040] The method of the application is further described below in combination with an embodiment:

[0041] Burst signal detection: The WiFi receiver assumes that the following wireless signal segment is received, which contains five signal bursts in total, the signal adopts the IEEE802.11a protocol, the sampling rate is 20MHz, and the time-domain waveform diagram of the signal is shown in Figure 3 ;

[0042] The signal is input into the signal detection module;

[0043] The modulus square sum and the autocorrelation characteristics thereof are calculated respectively, the frame arrival detection is performed in the signal detection module according to the autocorrelation characteristics, and the starting position of the complete signal burst is acquired. Then, the modulus square (i.e. the energy value) of the starting position is used to update the energy detection threshold, so that the ending position of the complete signal burst is detected. The absolute index value of the starting and ending positions of the detected burst signal in the data stream is recorded, and the detection result is shown in Table 2:

[0044] Table 2: Detection result schematic table

[0045] Nth burst burst position information ([start position, end position]) first burst [38，27244] second burst [47239，74445] third burst [94438，121654] fourth burst [141639，168844] fifth burst [188839，216045]

[0046] Creating a stream label for the burst position: the initial stream label is created by calling the add_item_tag() function in GNU Radio;

[0047] Taking the first burst as an example, the which_output parameter is set to 0, i.e. the index value of the 0th port; the abs_offset parameter is set to the starting position 38 of the fourth signal burst; the key parameter is set to the string "block1", indicating the type of the label; the value parameter is set to the absolute index value [38, 27244] of the recorded starting and ending positions of the signal burst; the srcid parameter is not filled by default. The creation of the stream label is completed by calling the add_item_tag() function.

[0048] The initial stream labels of the five signal bursts are created in sequence. Referring toFigure 4 ; Figure 4 The signal stream with the initial flow label bound for the signal detection module output;

[0049] Transmission and update of the flow label: At this time, the signal stream with the initial flow label bound for the signal detection module output is transmitted to the downstream module, and in the subsequent WiFi signal processing module, the flow label of the input data stream is extracted respectively, and a flow label is updated and bound for the output data at the output end of the module;

[0050] Take the long training sequence synchronization module and the fourth signal burst as an example. After the fourth signal burst is processed by the long training sequence synchronization module, the flow label needs to be updated and bound at the output end. When the first data of the remaining part of the burst is output, the interface provided by the GNU Radio framework is used to call the function nitems-written() to obtain the absolute index value 102720 of the data in the signal stream, the offset parameter (abs_offset) 141639 of the flow label is updated to 102720, and the value parameter remains unchanged [141639, 168844], so as to bind the flow label with the data and ensure the correspondence between the label and the processed signal burst.

[0051] Step four, establish the mapping relationship between the burst signal and the MAC address: the MAC PDU decoding algorithm obtains the data stream and the flow label from the upstream module, and completes the symbol mapping step in the WiFi signal processing process in this module to obtain the complete MAC PDU. The value parameter value [X1, X2] of the flow label and the MAC PDU are transmitted to the MAC address analysis module through the available message passing mechanism, and the decoding work of the MAC PDU is completed in the module. It should be noted that the transmission of the MAC PDU from the decoding module to the analysis module is not in the form of data stream, but through the message port by calling the message_port_pub() function.

[0052] The MAC address analysis module receives the MAC PDU and the label value in the message, decodes the MAC PDU to obtain the MAC address of the signal burst, forms a matching data pair with the value parameter value of the flow label and the MAC address, and refers to Figure 5 , the matching result of the fourth signal burst;

[0053] The matching data pair is added to the established storage record, and finally a signal burst position-MAC address mapping table is obtained, as shown in Table 3:

[0054] Table 3 Signal burst position-MAC address mapping table

[0055]

[0056] Thus, mapping of WiFi signal bursts to MAC addresses is achieved.

Claims

1. A method for mapping WiFi signal burst to MAC layer protocol data unit, comprising the following steps: S1. obtaining input WiFi signal stream; S2. detecting burst signal from the obtained signal stream; S3. creating a stream tag for burst position according to the detection result obtained in step S2; specifically comprising the following steps: creating a stream tag using stream tag creation interface in GNU Radio framework; the parameters of the stream tag include output port, offset and value: the output port is used to indicate the destination module of the stream tag transmission, and the parameter of the output port is set as the index of the corresponding output end; the offset is used to indicate the absolute index value of the tag position, and is set as the starting position of the recorded signal burst; the value is used to record the absolute index value X1 of the starting position of the signal burst in the data stream and the absolute index value X2 of the ending position of the burst signal in the data stream, and the value is set as [X1, X2]; S4. updating and binding the stream tag for output data according to the stream tag obtained in step S3; specifically comprising the following steps: When the complete WiFi signal burst passes through the subsequent module, the specific signal part in a physical frame will be removed; at this time, the stream tag obtained in step S3 is updated and bound in the output signal: the absolute index value X3 of the corresponding data in the signal stream is obtained by using the interface provided by the GNU Radio framework in the remaining part of the output signal after being truncated, and the offset parameter of the stream tag is updated to X3, and the value of the stream tag is kept unchanged; finally, the stream tag is bound with the data, which ensures the corresponding relationship between the tag and the processed signal burst; S5. completing symbol mapping in WiFi signal processing process by MAC layer protocol data unit decoding algorithm according to the obtained stream tag, and establishing the mapping relationship between WiFi signal burst and MAC layer protocol data unit; wherein the symbol mapping in WiFi signal processing process by MAC layer protocol data unit decoding algorithm according to the obtained stream tag, specifically comprising the following steps: obtaining data stream and stream tag, completing symbol mapping in WiFi signal processing process by MAC layer protocol data unit decoding algorithm, obtaining complete MAC layer protocol data unit; passing the value [X1, X2] of the stream tag and the MAC PDU to the MAC address analysis module through the message passing mechanism, and decoding the MAC PDU in the module; once the MAC address analysis module outputs the analyzed MAC address MAC1, forming a matching data pair with the value [X1, X2] in the stream tag and MAC1 and storing, and completing the mapping between signal burst and MAC address.

2. The method of mapping WiFi signal bursts to MAC layer protocol data units of claim 1, wherein the detection of burst signal from the obtained signal stream in step S2, specifically comprising the following steps: obtaining the starting position and ending position of the complete signal burst in the signal stream by burst signal detection method, and recording the absolute index value X1 of the starting position of the detected burst signal in the data stream and the absolute index value X2 of the ending position of the burst signal in the data stream.

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