CN113194464B - Internet of things physical layer covert communication method and device based on frequency spectrum detection - Google Patents

Internet of things physical layer covert communication method and device based on frequency spectrum detection Download PDF

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CN113194464B
CN113194464B CN202110455229.4A CN202110455229A CN113194464B CN 113194464 B CN113194464 B CN 113194464B CN 202110455229 A CN202110455229 A CN 202110455229A CN 113194464 B CN113194464 B CN 113194464B
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于季弘
杜彩卉
刘家豪
王帅
安建平
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Beijing Institute of Technology BIT
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/12—Modulator circuits; Transmitter circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/14—Demodulator circuits; Receiver circuits
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

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Abstract

The invention discloses a method and a device for covert communication of an Internet of things physical layer based on spectrum detection, and belongs to the field of wireless communication. The invention carries out pulse modulation at a transmitting end aiming at a physical layer radio frequency end of an Internet of things signal transmission system, and moves partial spectrum energy of an original transmission signal to an idle frequency band, thereby realizing the modulation aiming at the hidden information; the signal spectrum energy of the appointed frequency band is detected at the receiving end, so that the demodulation of the hidden signal is realized. Compared with the traditional signal encryption means and the demodulation mode aiming at the signal time domain information, the invention has the characteristics of low power consumption, low cost, high concealment and high reliability while not changing the hardware and the transmission mode of the original transmission system. And in a certain range, the transmission reliability can be improved by increasing the transmission power of the hidden information, or the transmission concealment can be improved by reducing the transmission power of the hidden information. The invention can be widely applied to the existing transmission equipment of the Internet of things.

Description

Internet of things physical layer covert communication method and device based on frequency spectrum detection
Technical Field
The invention relates to a method and a device for covert communication of an Internet of things physical layer based on spectrum detection, and belongs to the field of wireless communication.
Background
The commonly used wireless communication technologies of the internet of things include a Zigbee technology, a WiFi technology, a Bluetooth technology, a LoRa technology, and the like. The signal energy transmitted by the technologies is concentrated on a designated frequency band, so that if pulse modulation is performed on a physical layer radio frequency end signal of an internet of things signal transmission system at a radio frequency end for signal transmission by an on-off keying mode, partial energy of the signal can be moved to an idle frequency band, namely, a hidden channel can be established on the basis of not influencing an original signal, and modulation on hidden information is completed. And the demodulation aiming at the hidden information can be completed by detecting the frequency spectrum energy of the corresponding frequency band at the receiving end.
At present, the existing covert transmission method mainly adopts an encryption technology based on a secret key at a data link layer, but the encryption technology has the limitations of complex structure and need of designing a special transmitter and a special receiver; and the ciphertext of the encryption technology in the transmission process is relatively lack of concealment relative to the monitoring end, and is easy to attack.
Disclosure of Invention
The invention aims to provide a method and a device for covert communication of an Internet of things physical layer based on spectrum detection, which have the characteristics of simple structure, high realizability, strong concealment and the like.
The purpose of the invention is realized by the following technical mode: at a transmitting end, the original signal is subjected to pulse modulation in a mode of carrying out on-off keying on the radio frequency front end of an original transmission system, so that a pulse signal containing hidden information is embedded in the original signal, and the modulated signal is transmitted out through an antenna, so that the purpose of transmitting the hidden information by taking the original internet of things signal as a carrier is achieved.
Since the pulse width of the concealment signal is lower than the sampling period of the original baseband signal of the internet of things, the signal transmission involved in the invention will not affect the transmission of the original signal. The hidden channel established by the method and the device can not be monitored directly, and the method and the device have the advantages of simple structure, easy realization, strong concealment, no influence on the receiving and transmitting of the original transmission system, no limitation of the signal modulation system of the original transmission system, application to the existing mature transmitting system of the internet of things and the like, and can realize the low-power-consumption and high-reliability hidden transmission. Meanwhile, the invention can reduce the transmission power of the hidden signal and improve the concealment of the transmission of the hidden information by reducing the pulse width or the period of pulse modulation on the basis of not influencing the transmission of the original system; or the pulse width or the period of the pulse modulation is increased, so that the transmission power of the hidden signal is increased, and the reliability of the transmission of the hidden information is improved.
An Internet of things physical layer covert communication method based on spectrum detection comprises the following steps:
step 1, a hidden information acquisition and storage module continuously acquires hidden information to be transmitted from an environment or an upper computer and stores the hidden information in a register;
step 2, the instruction sending computer sets the pulse modulation period based on the requirement;
step 3, the instruction sending computer sends a wake-up instruction to the hidden information acquisition and modulation module, the hidden information storage module starts to read the existing hidden information from the register, and a serial single-bit hidden information data stream B is obtained through the encoding module;
step 4, the control module converts the hidden information data stream B into a level signal C which is used as control information for impedance switching of the radio frequency switch;
step 5, the radio frequency switch modulates the radio frequency signal of the original transmission system based on the level signal C, and sends the modulated signal out by a radio frequency antenna;
and 6, the covert receiver detects the frequency spectrum energy of the designated frequency band to realize the demodulation of the covert signal.
Further, the radio frequency switch in step 5 modulates the radio frequency signal of the original transmission system in the following manner:
firstly, a single-pole double-throw radio frequency switch is used for carrying out impedance switching based on a level signal C, and then a branch signal after the switch switching is delayed for a certain time length and is added with an original branch signal through a combiner. Let the original transmission system radio frequency signal A be y (T), when the hidden information data is transmitted 0, the impedance switch is kept in the closed state when the level signal C is low level, and when the hidden information data stream is transmitted 1, C is period T1Duration of T2Is switched on and off according to the period T1Performing impedance switching for a duration T2. And for a duration of N times the switching period of the impedance switch, i.e. T2＝NT1。
Then when C is low, the output signal D1 is: y isD1(t) ═ y (t); the output signal D2 is: y isD2(t) ═ 0; the combined signal D is: y isD(t)＝y(t)。
When C is high, the output signal D1 is:
Figure BDA0003040288020000021
let the delay of D2 with respect to D1 be τ, the output signal D2 is:
Figure BDA0003040288020000031
after the signals D1 and D2 are combined by the combiner, the output signals are:
Figure BDA0003040288020000032
in this way, the original information is pulse modulated when the covert information is transmitted 1.
Further, the concealed receiver in step 6 demodulates the concealed information in the following manner:
if the spectrum corresponding to the original transmission signal C is y (f), when 0 is sent, the spectrum corresponding to the receiving end is y (f).
And when transmitting 1, the time domain waveform of the receiving end can be equivalent to:
Figure BDA0003040288020000033
therefore, the corresponding spectrum is:
Figure BDA0003040288020000041
it can be seen that when transmitting 1, the spectrum of the receiving end is compared with the interval when transmitting 0
Figure BDA0003040288020000042
Has been convolved, i.e. 1 is transmitted, the spectrum is spaced as
Figure BDA0003040288020000043
The period of (2) is extended. Based on the method, the corresponding hidden information can be demodulated by detecting the frequency spectrum energy of the corresponding frequency point of the frequency spectrum after the period extension.
Specifically, the method comprises the following steps:
6-1, the hidden information receiving end determines a receiving frequency point of a hidden signal according to a pulse period and an original Internet of things signal transmission system;
step 6-2, the hidden information receiving end carries out synchronization aiming at the received signals;
step 6-3, concealing the information receiving end to detect the frequency spectrum energy of the corresponding frequency point;
6-4, the hidden information receiving end carries out self-adaptive threshold judgment aiming at the frequency spectrum energy of the corresponding frequency point to obtain a single-bit data stream;
and 6-5, the hidden information receiving end decodes the corresponding single-bit data stream to acquire the hidden information.
In this process, if a conventional receiver exists, as shown in step 5, when C is low level, the signal received by the conventional receiver (which may be referred to as E1) is the original internet of things transmission signal D, and can be demodulated normally;
when C is high level, the signal E1 received by the conventional receiver is the original Internet of things transmission signal with the superposition period T1Duration of T2＝NT1Pulse signal of width τ, where T2＝NT1. At this time, let the sampling period of the receiving end for E1 be TsThen the actually received signal is:
Figure BDA0003040288020000051
thus, if τ is<TsAnd then:
Figure BDA0003040288020000052
therefore, when the pulse width is smaller than the sampling period, the transmission of the hidden information does not affect the transmission of the original signal. Therefore, the conventional receiver can obtain the sending information of the original transmission system through the carrier synchronization module, the frame header synchronization module and the de-framing decoding module aiming at the received signals.
Advantageous effects
1. Compared with the existing digital quadrature modulation technology, the analog modulation technology for additionally modulating the radio frequency front end of the transmission system of the Internet of things is independent of the hardware structure or the signal modulation mode of the original Internet of things transmission system, and the hardware structure or the signal modulation mode of the original Internet of things transmission system does not need to be changed or limited. Therefore, the invention can be widely applied to the existing mature transmission system of the Internet of things.
2. Compared with the prior information encryption technology, the invention is a hiding method based on the physical layer information of the transmission system of the Internet of things, the frequency spectrum is moved to the hidden information, and the energy of the hidden signal is low, so that the original transmission system is not influenced, and the interference to other transmission systems possibly existing in the space is not caused. Meanwhile, the hidden information cannot be obtained by adopting a common decoding mode, and the system confidentiality is strong.
3. Aiming at the demodulation of the hidden information, the invention adopts a mode of detecting the frequency spectrum energy of the signal and demodulates the signal frequency domain, compared with the traditional method of demodulating the signal time domain information, the invention has small influence caused by the environmental change and is not easy to be interfered by the channel noise (such as Gaussian noise and white noise).
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FIG. 1 is a flow chart of the Internet of things physical layer covert communication method based on spectrum detection
Fig. 2 is a block diagram of a structure of a covert communication transmission device of an internet of things physical layer based on spectrum detection according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a transmitting end of an Internet of things physical layer covert communication device based on spectrum detection according to an embodiment of the invention;
FIG. 4 is a schematic structural diagram of a receiving end of an Internet of things physical layer covert communication device based on spectrum detection according to an embodiment of the invention;
FIG. 5 is a schematic diagram of a frequency domain waveform at a receiving end according to an embodiment of the present invention
Wherein, fig. a is a schematic diagram of a receiving end frequency domain waveform provided by the embodiment of the present invention when hidden information is sent to 0; fig. b is a schematic diagram of a frequency domain waveform of a receiving end according to an embodiment of the present invention when hidden information is transmitted 1;
FIG. 6 is a schematic diagram of an indoor test scenario provided by an embodiment of the present invention
FIG. 7 is a schematic diagram of a receiving end error rate according to an embodiment of the present invention
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings and examples. The technical problems and the advantages solved by the technical solutions of the present invention are also described, and it should be noted that the described embodiments are only intended to facilitate the understanding of the present invention, and do not have any limiting effect.
The present embodiment adopts a WiFi signal based on 802.11g protocol as an original internet of things transmission signal. The WiFi transmission system adopts a 16-QAM modulation mode for baseband signals, adopts 64-point FFT and 16-bit cyclic prefix, the information transmission rate is about 1Mbps, and the pulse width of signal modulation is about 1/20 of the sampling rate. The physical layer covert communication specific implementation steps aiming at the WiFi transmission system are as follows:
step 1, a hidden information acquisition and storage module continuously acquires hidden information to be transmitted from an environment or an upper computer and stores the hidden information in a register;
step 2, the hidden information coding module sets a pulse modulation period based on the requirement and the original transmission signal of the Internet of things;
step 3, the instruction sending computer sends a wake-up instruction to the hidden information acquisition and modulation module, the hidden information storage module starts to read the stored hidden information from the register, and a serial single-bit hidden information data stream B is obtained through the encoding module;
and 4, converting the hidden information data stream B into a level signal C by the control module, and using the level signal C as control information for impedance switching of the radio frequency switch. The radio frequency switch switches the impedance of the radio frequency antenna through the switch based on the control information, delays one branch signal after the switch is switched for a certain time length, and then adds the branch signal with the original branch signal through the combiner, so that the transmission of the physical layer hidden information based on pulse modulation is realized. The modulated signal is sent out by a radio frequency antenna;
and step 5, determining the frequency point of the received signal by a frequency spectrum energy detection module of the hidden information receiving end based on the original WiFi transmission system. Fig. 5 a and b show frequency domain waveforms of signals respectively received by the receiving end when the invention transmits 0 and 1, respectively. It can be seen that, since the pulse width is about 1/20 of the sampling period, the spectral energy at the corresponding frequency point of the original signal does not change significantly when transmitting 0 or 1.
When transmitting 1, extra spectrum energy shifted by pulse modulation is generated on the frequency band outside the range of the original transmission signal, and when transmitting 0, the spectrum energy of the receiving end at the frequency point is similar to the spectrum energy of Gaussian white noise at the point.
Aiming at the frequency spectrum in the step 5, a hidden information demodulation module in a hidden information receiving end can obtain a 01 sequence corresponding to the hidden information through threshold self-adaptive judgment, and the hidden information can be correspondingly solved according to the coding form of the hidden information, namely an m sequence
Specifically, the present embodiment was tested in an indoor scenario as shown in fig. 6. The power of the transmitting device Tx is set to 15dBm, the receiving power of the receiving device A, B, C, D, E, F, G is set to 60dB, the placement position is shown in fig. 6, and the hidden information error rate curve corresponding to the test result is shown in fig. 7. The A, B, C, D, E, F, G equipment can complete demodulation accurately for the original signal, namely the error rate is 0. For the hidden information, the A, B, C, D, F device can complete demodulation without error, namely the error rate is 0. The error rate of the E equipment for the hidden information is 0.13%; the error rate of the G device for the hidden information is 0.51 percent;
in the experiment, the original internet of things signal transmitting module, the frequency spectrum energy detecting module and the hidden information demodulating module all adopt software radio platforms of USRP B210 of ETTUS company;
the hidden information acquisition and storage module and the hidden information coding module adopt an MSP430G2553 microprocessor chip of TEXAS INSTRUMENT company.
The control module and the impedance switching module adopt an ANALOG DEVICES family HMC radio frequency switch, and different types of radio frequency switches are selected according to different modulation modes and modulation rates of the hidden information, and the control module and the impedance switching module are specifically divided into an SPST radio frequency switch HMC1055, an SPDT radio frequency switch HMC284, an SP4T radio frequency switch HMC241, an SP8T radio frequency switch HMC253 and the like.
Under the experimental conditions, the maximum transmission distance of the sending device for sending the hidden information is greater than or equal to 16.8 m. It should be emphasized that, in the implementation, the transmission distance can be further increased by increasing the received power, increasing the pulse switching period, increasing the pulse width on the premise of being less than the sampling frequency, and the like, without affecting the original signal. The hidden information can be further encrypted by means of encryption modes such as link encryption, node encryption, end-to-end encryption and the like, so that the security of transmission of the hidden information is guaranteed.
The transmission of the concealed information can be realized by the physical layer concealed transmission method of the WiFi modulation signal based on the 802.11g protocol. Because the information hiding and demodulation does not affect the modulation and demodulation of the original transmission system in the transmission process, and the energy of the hidden signal is lower and can be controlled according to the requirement, the possibility that the hidden transmission system is discovered is greatly reduced;
the above description is only for the preferred embodiments of the present invention and is not intended to limit the embodiments of the present invention. Variations and modifications in other variations will occur to those skilled in the art upon reading the foregoing description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed, and obviously, many modifications and variations are possible in light of the above teaching.

Claims (4)

1. An Internet of things physical layer covert communication method based on spectrum detection is characterized by comprising the following steps:
step 1, a hidden information acquisition and storage module continuously acquires hidden information to be transmitted from an environment or an upper computer and stores the hidden information in a register;
step 2, the instruction sending computer sets the pulse modulation period based on the requirement;
step 3, the instruction sending computer sends a wake-up instruction to the hidden information acquisition and modulation module, the hidden information acquisition and storage module starts to read the existing hidden information from the register, and a serial single-bit hidden information data stream B is obtained through the encoding module;
step 4, the control module converts the hidden information data stream B into a level signal C which is used as control information for impedance switching of the radio frequency switch;
step 5, the radio frequency switch modulates the radio frequency signal of the original transmission system based on the level signal C, and sends the modulated signal out by a radio frequency antenna;
and 6, the covert receiver detects the frequency spectrum energy of the designated frequency band to realize the demodulation of the covert signal.
2. The Internet of things physical layer covert communication method based on spectrum detection as claimed in claim 1, wherein the implementation method of step 5 is as follows:
firstly, a single-pole double-throw radio frequency switch is used for carrying out impedance switching based on a level signal C, and then a branch signal after the switch switching is delayed for a certain time length and added with an original branch signal through a combiner; let the original transmission system radio frequency signal A be y (T), when the hidden information data is transmitted 0, the impedance switch is kept in the closed state when the level signal C is low level, and when the hidden information data stream is transmitted 1, C is period T1Duration of T2According to the period T, impedance switching1Performing impedance switching for a duration T2(ii) a And for a duration of N times the switching period of the impedance switch, i.e. T2＝NT1；
Then when C is low, the output signal D1 is: y isD1(t) ═ y (t); the output signal D2 is: y isD2(t) ═ 0; the combined signal D is: y isD(t)＝y(t)；
When C is high, the output signal D1 is:
Figure FDA0003514792820000011
let the delay of D2 with respect to D1 be τ, the output signal D2 is:
Figure FDA0003514792820000012
after the signals D1 and D2 are combined by the combiner, the output signals are:
Figure FDA0003514792820000021
in this way, the original information is pulse modulated when the covert information is transmitted 1.
3. The Internet of things physical layer covert communication method based on spectrum detection as claimed in claim 1, wherein the implementation method of step 6 is as follows:
if the frequency spectrum corresponding to the original transmission signal C is y (f), when 0 is sent, the frequency spectrum corresponding to the receiving end is y (f);
and when transmitting 1, the time domain waveform of the receiving end can be equivalent to:
Figure FDA0003514792820000022
therefore, the corresponding spectrum is:
Figure FDA0003514792820000023
it can be seen that when transmitting 1, the spectrum of the receiving end is compared with the interval when transmitting 0
Figure FDA0003514792820000024
Has been convolved, i.e. 1 is transmitted, the spectrum is spaced as
Figure FDA0003514792820000031
The period of (3) is prolonged; based on the method, the corresponding hidden information can be demodulated by detecting the frequency spectrum energy of the corresponding frequency point of the frequency spectrum after the period extension.
4. The Internet of things physical layer covert communication method based on spectrum detection as claimed in claim 1 or 3, wherein the concrete implementation steps of step 6 are as follows:
6-1, the hidden information receiving end determines a receiving frequency point of a hidden signal according to a pulse period and an original Internet of things signal transmission system;
step 6-2, the hidden information receiving end carries out synchronization aiming at the received signals;
step 6-3, concealing the information receiving end to detect the frequency spectrum energy of the corresponding frequency point;
6-4, the hidden information receiving end carries out self-adaptive threshold judgment aiming at the frequency spectrum energy of the corresponding frequency point to obtain a single-bit data stream;
6-5, the hidden information receiving end decodes the corresponding single-bit data stream to obtain the hidden information;
in this process, if there is a conventional receiver, as shown in step 5, when C is low level, the signal E1 received by the conventional receiver is the original internet of things transmission signal D, and can be demodulated normally;
when C is high level, the signal E1 received by the conventional receiver is the original Internet of things transmission signal with the superposition period T1Duration of T2＝NT1Pulse signal of width τ, where T2＝NT1(ii) a At this time, let the sampling period of the receiving end for E1 be TsThen the actually received signal is:
Figure FDA0003514792820000032
thus, if τ < TsAnd then:
Figure FDA0003514792820000033
therefore, when the pulse width is smaller than the sampling period, the transmission of the hidden information does not influence the transmission of the original signal; therefore, the conventional receiver can obtain the sending information of the original transmission system through the carrier synchronization module, the frame header synchronization module and the de-framing decoding module aiming at the received signals.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104539375A (en) * 2014-12-12 2015-04-22 中国电子科技集团公司第四十一研究所 Rapid recognition method for highly masking signals
CN108966223A (en) * 2018-04-28 2018-12-07 深圳大学 Physical layer authentication method and system based on single-bit concealment agreement

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6252962B1 (en) * 1994-04-22 2001-06-26 Raytheon Company Featureless covert communication system
JP5581449B2 (en) * 2010-08-24 2014-08-27 ドルビー・インターナショナル・アーベー Concealment of intermittent mono reception of FM stereo radio receiver
US8644362B1 (en) * 2011-09-01 2014-02-04 The SI Organization, Inc. Hybrid pseudo-random noise and chaotic signal implementation for covert communication

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104539375A (en) * 2014-12-12 2015-04-22 中国电子科技集团公司第四十一研究所 Rapid recognition method for highly masking signals
CN108966223A (en) * 2018-04-28 2018-12-07 深圳大学 Physical layer authentication method and system based on single-bit concealment agreement

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Distance-Adaptive Absorption-Peak Hopping (DA-APH) Modulation for Terahertz Covert Communications;GAO,Wenjun等;《2019 IEEE Global Communications Conference (GLOBECOM)》;20200227;全文 *
基于LED显示屏的隐蔽光传输通道;胡浩等;《通信技术》;20180710(第07期);全文 *

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