Stepped carrier on-off keying method for integrated sensing and communication system in thz band

Abstract

The present invention relates to stepped carrier On-Off keying method for integrated sensing and communication system in THz band. Main purpose of the invention is to provide to create an ISAC structure with OOK modulation, which is among the important requirements for 6G.

Description

[0001] Stepped Carrier On-Off Keying Method For Integrated Sensing and Communication System in THz Band

[0002] TECHNICAL FIELD

[0003] The present invention relates to stepped carrier On-Off keying method for integrated sensing and communication (ISAC) system in THz (TeraHertz) band.

[0004] PRIOR ART

[0005] Sensing is as important as communication for 6G in the THz (TeraHertz) band. 6G networks prioritize ultra-fast data transfer, minimal latency, and energy efficiency, with the terahertz (THz) band as a key element. THz systems also demonstrate impressive capabilities in high-resolution sensing due to their wide bandwidth and narrow beamwidth in the given reference document [1]. Terahertz integrated sensing and communication (ISAC) is considered a revolutionary technology for achieving connected intelligence in 6G and future systems in the given reference document [2], On-Off Keying (OOK) modulation is an important modulation technique for THz Communication and is recommended for low-cost devices in IEEE 802.15.3d standards in the given reference document [3].

[0006] There are some studies in the literature for ISAC systems in the THz band. One of these is the study done by integrating sensing into DFT-s-OFDM, another waveform recommended for THz communication in the given reference document [4], But this waveform includes signal processing techniques such as FFT, which are complex for low-cost THz devices. In the given reference document [5], sensing is done by sending signals in different subbands with some special sequences, and communication is achieved by embedding data by making resource allocation. In the given reference document [6], an ISAC system for inter-satellite link is proposed by using chirp signals for space debris radar applications and embedding data according to the shape of the chirp signals. Another related topic in the THz band is OOK modulation which is used for communication, and stepped carrier technique is a widely used technique for sensing, which uses the correlation of signals sent from different sub-bands. OOK modulation is important for communication in the THz band, but there is no ISAC system that combines both sensing and communication with OOK modulation.

[0007] All the problems mentioned above have made it necessary to make an innovation in the relevant technical field as a result.

[0008] BRIEF DESCRIPTION OF THE INVENTION

[0009] The present invention relates to stepped carrier On-Off keying method for integrated sensing and communication (ISAC) in THz (TeraHertz) band to eliminate the above- mentioned disadvantages and bring new advantages to the relevant technical field.

[0010] THz band has quite wide bandwidth. Wide bandwidth provides sensing in a quiet high resolution. And also, THz works with high frequencies in communication. In this way, it is possible to high data transmission in communication. By benefiting from these features of THz band, the invention enables integrated sensing and communication in THz (TeraHertz) band to be brought together.

[0011] The main object of the invention is to provide to create an ISAC structure with On-Off Keying (OOK) modulation, which is among the important requirements for 6G.

[0012] This invention, unlike prior art documents, uses the OOK modulation technique to send data, and includes unique algorithms, transmitter and receiver designs, and unique hopping patterns to implement the stepped carrier technique. The OOK modulation technique used for communication and the stepped carrier technique used for sensing are both simple techniques and suitable for low-cost THz devices.

[0013] The main aim of the invention is to create an integrated sensing and communication system to be used in the THz band by adding sensing capability to On-Off keying modulation. To do this, the invention uses step carrier technique. To scan wide band, after each sending signal, passing different bands means carrier frequency changes. In this way, it is possible to scan sensitive sensing.

[0014] Higher resolution sensing is obtained from the correlations of the signals, target sensing is performed, that is, range and velocity estimation can be performed.

[0015] THz band provides to use sensing in milimeter levels and THz has quite wide bandwidth. On the other hand, On-Off keying is a single carrier it means power is constant. So the invention uses the On-Off keying method. There is no need for digital modulation. It helps to pass other band. On-Off keying provides data transfer.

[0016] In the first aspect, the embodiment of the present application provides a stepped carrier On-Off keying method, which can be executed by a network device, or by a component of the network device (such as a processor, a chip, or a chip system, etc.), or can be implemented by all or logical modules or software implementations of some network device functions or computer implemented device.

[0017] In the proposed invention, there are two different sub-band hopping patterns used for the stepped carrier technique as linear and data dependent.

[0018] Through this method that makes it possible to combine both sensing and communication with OOK modulation in ISAC system.

[0019] The stepped carrier On-Off keying method proposed by the embodiment of the present application can be applied to the 6G or similar networks.

[0020] To achieve all the objects mentioned above and that will emerge from the following detailed description.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present disclosure, in accordance with one or more various examples, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict examples of the disclosure. These drawings are provided to facilitate the reader's understanding of the disclosure and should not be considered limiting the breadth, scope, or applicability of the disclosure. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale.

[0023] Figure 1 : Transmitter block diagram

[0024] Figure 2: Receiver block diagram

[0025] Figure 3: Linear frequency hopping pattern

[0026] Figure 4: Data dependent frequency hopping pattern

[0027] Figure 5: Transmitter Algorithm

[0028] Figure 6: Receiver Algorithm

[0029] REFERENCE LIST

[0030] The reference numbers of the elements included in the figures are explained below.

[0031] 101 Bit sequence

[0032] 102 OOK modulation

[0033] 103 Digital to Analog Converter (DAC)

[0034] 104 Mixer

[0035] 105 High Power Amplifier (HPA)

[0036] 106 T ransmitter antenna

[0037] 107 Frequency synthesizer

[0038] 202 OOK demodulation

[0039] 203 Analog to Digital Converter (ADC)

[0040] 205 Low Noise Amplifier (LNA)

[0041] 206 Receiver antenna

[0042] 208 Correlation

[0043] 209 Range Velocity estimation

[0044] 301 The black squares

[0045] 302 The shaded squares

[0046] 303 The white squares DETAILED DESCRIPTION OF THE INVENTION

[0047] In this detailed description, the subject matter is explained with references to examples without forming any restrictive effect only to make the subject more understandable.

[0048] The invention relates to stepped carrier On-Off keying method for integrated sensing and communication system in THz (TeraHertz) band which is shown in figure 5 and figure 6.

[0049] In the invention, mainly used of two structures which are transmitter and receiver. The main novelty of invention is using frequency synthesizer (107) and frequency synthesizer (107) receiving feedback from bit sequences (101 ). In this way, it is possible to pass higher frequencies on the transmitter.

[0050] In the invention, there are two different sub-band hopping patterns used for the stepped carrier technique as linear and data dependent. In the linear hopping pattern, the transition between sub-bands is done linearly. In the data dependent hopping pattern, the transition between sub-bands is made according to the incoming data bits, and since the data bits will constantly change randomly, the hopping pattern cannot be predicted, therefore it can provide safer communication against jamming.

[0051] A unique ISAC system is created by adding the stepped carrier technique to OOK modulation (102) in the proposed invention. Carrier frequency is not constant, it is continuously changing in the invention.

[0052] An ISAC system that communicates with the OOK modulation (102) technique and performs sensing with the stepped frequency technique is presented. This system is suitable for use in bistatic and monostatic ISAC applications.

[0053] The transmitter in ISAC system comprises;

[0054] • At least one OOK modulation (102) which is for applying amplitude shift keying modulation to the bit sequence (101 ), • At least one Digital to Analog Converter (DAC) (103) which is used to translate the digital information that represents the communication signal into an analog waveform that can be transmitted over the air,

[0055] • At least one mixer (104) is used to shift the frequency of a signal to THz frequencies,

[0056] • At least one High Power Amplifier (HPA) (105) High Power Amplifier (HPA) (105) which is used to amplify the signal to a certain SNR level to achieve the bit error rate (BER) required for the system. As the SNR increases, the quality of the received signal improves relative to the noise, leading to a lower probability of errors in decoding the transmitted bits.

[0057] • At least one transmitter antenna (106) which sends the signal to receiver,

[0058] • At least one frequency synthesizer (107) which is provided to determine the center frequency of the signal according to the hopping pattern,

[0059] The transmitter structure of the proposed method is illustrated in Figure 1. OOK modulation (102) is applied to the bit sequence (101 ). OOK modulation (102) is the simplest version of amplitude shift keying modulation. It represents the binary data 1 as presence of a carrier wave and binary data 0 as absence of a carrier wave. After OOK modulation (102), Digital to Analog Converter (DAC) (103) is used to translate the digital information that represents the communication signal into an analog waveform that can be transmitted over the air. After that, a mixer (104) is used to shift the frequency of a signal to THz frequencies. The center frequency of the signal is determined by the frequency synthesizer (107). The frequency synthesizer (107) determines the center frequency according to the hopping pattern. There are two different hopping patterns as linear and data dependent. In the linear hopping pattern, the next sub-band is switched linearly at each stage. In the data dependent hopping pattern, if the incoming binary data is 1 , it moves to the next sub-band, if it is 0, it stays in the same sub-band. If the incoming binary data is 1 , a signal is generated in that sub-band, if zero, no signal is generated. Therefore, the frequency synthesizer (107) works according to the incoming data bits. After mixer, High Power Amplifier (HPA) (105) is used to amplify the signal to a sufficient power level for reliable transmission. Finally, the signal is sent from the transmitter antenna (106). In the proposed idea, unlike the transmitter designs for OOK modulation (102) found in the literature, a uniquely designed frequency synthesizer (107) is used, which switches different subbands according to the incoming data bits.

[0060] The receiver in ISAC system comprises;

[0061] • At least one receiver antenna (206) which is received the transmitted signal from transmitter,

[0062] • At least one Low Noise Amplifier (LNA) (205) which is used to which is used to amplify incoming signals below a certain signal to noise ratio (SNR) value, (so that they do not exceed the desired Noise Figure (NF). In practical terms, the Noise Figure is a common metric used to quantify the amount of noise added by the amplifier. The lower the Noise Figure, the better the LNA is at maintaining a low noise environment for the signal.)

[0063] • At least one mixer (104) is used to shift the frequency of a received signal to baseband frequency,

[0064] • At least one frequency Synthesizer (107) which is used for generating a local oscillator signal at a specific frequency according to the hopping pattern,

[0065] • Correlator which is providing to performing of apply correlation (208) to signals from different frequencies for sensing,

[0066] • Range velocity estimator is performing range and velocity estimation (209) according to the results (The correlation results provide information about the delay or phase shift in the received signal, as well as any frequency shifts due to the Doppler effect. These results are then processed to extract the range and velocity information of the target objects in the sensing environment. By measuring the time delay or phase shift, the system can calculate the distance to the target using the speed of light. Doppler effect is often employed for velocity estimation. The Doppler effect causes a frequency shift in the received signal when the target is in motion.) obtained from the correlation (208).

[0067] The receiver structure of the proposed method is illustrated in Figure 2. The signal is received from the receiver antenna (206). After receiving the signal, Low Noise Amplifier (LNA) (205) is used to amplify weak incoming signals with minimal additional noise. Low Noise Amplifier (LNA) (205) which is used to amplify incoming signals below a certain signal to noise ratio (SNR) value, (so that they do not exceed the desired Noise Figure (NF). In practical terms, the Noise Figure is a common metric used to quantify the amount of noise added by the amplifier. The lower the Noise Figure, the better the LNA is at maintaining a low noise environment for the signal.) After LNA, Frequency Synthesizer (107) generates a local oscillator signal at a specific frequency. This signal is mixed with the incoming radio frequency signal in the mixer stage of the receiver to down-convert it to baseband frequency. The frequency synthesizer (107) determines the center frequency according to the hopping pattern as in the transmitter part. In the linear hopping pattern, the next sub-band is switched linearly at each band / stage. In the data dependent hopping pattern, if the demodulated binary data is 1 , the demodulated binary data moves to the next sub-band, if the demodulated binary data is 0, it stays in the same sub-band. The transmitter and receiver must operate synchronously in the same sub-bands. Therefore, when the data dependent hopping pattern is used, the hopping pattern should be checked with different methods considering that the demodulated data may be incorrect. After the mixer, sensing is performed by applying correlation (208) to signals from different frequencies. Correlation (208) is performed according to bit sequence (101 ) and the correlation signal is generated according to the bit sequence after receiving signals from all subbands. Range velocity estimation (209) is performed according to the results obtained from the correlation (208). After the mixer, the Analog to Digital Converter (ADC) (203) is also applied to switch to the digital domain. Then OOK demodulation (202) is applied to obtain the bit sequence (101 ) again. OOK demodulation (202) checks the presence of the signal and demodulates the binary data as 1 if there is a signal and as binary data 0 if there is no signal. OOK modulation (102) compares the energy of the signal to a specified threshold to check for the presence of the signal. If the signal energy is below the specified threshold, it detects the signal as absent, if it is above it, it detects the signal as present. In the proposed idea, unlike the OOK demodulation (202) receiver designs found in the literature, a uniquely designed frequency synthesizer (107) is used, which switches different sub-bands according to the demodulated data bits, there is a unique correlation (208) part which is based on the demodulated bits, and there is a range velocity estimation (209) part. In the proposed idea, by providing two different patterns, the trade-off between maximum range and maximum velocity in the ISAC system is aimed. The formulas for range resolution and maximum range are given below: where A / ? is range resolution, c is speed of light, B is total bandwidth, rmaxis maximum range and N is total number of sub-bands in one block duration. The combination of N sub-bands from the lowest sub-band to the highest sub-band is defined as a block.

[0068] The formulas for velocity resolution and maximum velocity are given below:

[0069] Where Av is velocity resolution, c is speed of light, fcis carrier frequency, M is the total number of consecutive blocks, and Tsymis one block duration (Tsymis the scanning time of the whole band used in the frequency, it is the time to send all bits).

[0070] The linear frequency hopping pattern of the proposed method is illustrated in Figure 3. In this pattern, the black squares (301 ) represent resources to which binary data 1 is sent, the shaded squares (302) represent resources to which binary data 0 is sent, which no signal is sent, and the white squares (303) represent resources that are not used and can be used for other purposes. In this pattern, the transmitter and receiver switch to the next frequency after each symbol is transmitted. This is to keep the block duration short. If the incoming binary data is 1 , a signal is generated in that sub-band, if zero, no signal is generated. In this pattern, no signal is transmitted in the sub-bands corresponding to the zeros in the incoming bits, as switched to the next frequency after each symbol is transmitted. This reduces the total number of sub-bands (N), reduces the duration of a block (Tsym) and increases the total number of consecutive blocks (M). In range resolution (A / ?) , there will be no change because the total bandwidth (B) is fixed. The total number of sub-bands (N) decreases, which reduces the maximum range (rmax) ■ When the block duration ( Tsym) decreases, the velocity resolution (Av) does not change as the total number of consecutive blocks (M) increase at the same rate. Maximum velocity increase as the block duration decrease. In summary, in this pattern, there is no change in range and velocity resolution, while maximum range (rmax) decreases as the number of sub-bands (N) decreases, and maximum velocity increases as the block duration decreases.

[0071] The data dependent frequency hopping pattern of the proposed method is illustrated in Figure 3. In this pattern, the black squares (301 ) represent resources to which binary data 1 is sent, the shaded squares (302) represent resources to which binary data 0 is sent, which no signal is sent, and the white squares (303) represent resources that are not used and can be used for other purposes. In this pattern, the transmitter and receiver switch to the next frequency if the binary data to be sent or last received binary data is 1 , if it is 0, the transmitter and receiver stay on the same frequency. In this pattern, since the carrier frequency does not change until the incoming binary data is 1 , all sub-bands are used and signals from all sub-bands are correlated at the receiver side. While this increases the total number of sub-bands (N), it also increases the block duration Tsym) since the frequency does not change at times corresponding to binary 0 in order to use all sub-bands. As the block duration (Tsym) increases, the total number of consecutive blocks used (M) decreases. As with the linear hopping pattern, range resolution (A / ?) and velocity resolution (Av) do not change. As the total number of sub-bands (N) increases, the maximum range (rmax) increases, and as the block duration (rm) increases, the maximum velocity ( ) decreases.

[0072] While increasing the maximum velocity by sacrificing the maximum range in the linear hopping pattern, the maximum range is increased by sacrificing the maximum velocity in the data dependent hopping pattern. In these hopping patterns in the presented idea, unlike other hopping patterns used for the stepped carrier technique in the literature, some sub-bands cannot be used at certain times due to OOK modulation (102). That's why these patterns were needed.

[0073] In the proposed idea, algorithms have been developed for the transmitter and receiver. These algorithms are valid for two different hopping patterns. Here HP is defined as the hopping pattern. Hopping pattern (HP) = 0 represents linear hopping pattern, HP = 1 represents data dependent hopping pattern. N is defined as the total number of subbands and n is defined as the current sub-band. Figure 5 shows the transmitter algorithm of the proposed idea. After communication starts, a bit is taken from the incoming bit sequence (101 ) and the hopping pattern used is checked. If a linear hopping pattern is used (HP == 0), the carrier frequency is set to the next frequency (n = n+1 ), because in the linear hopping pattern, it is always switched to the next frequency, regardless of the incoming bit. If the data dependent hopping pattern is used (HP == 1 ), the carrier frequency is switched to the next frequency if the incoming bit is 1 , because unless the incoming bit is 1 in the data dependent hopping pattern, the carrier frequency is not set to the next frequency. Afterwards, sub-band control is performed. If the instant sub-band (n) is greater than the total sub-band (N), the instant sub-band is changed to 1 , otherwise no change is made. Afterwards, the incoming bit is checked. If the incoming bit is 1 , the carrier signal is generated, transmitted, and back to the beginning. If the incoming bit is 0, it goes back to the beginning without transmission, because OOK modulation (102) modulates bit 0 as the absence of the signal.

[0074] Figure 6 shows the receiver algorithm of the proposed idea. After communication starts, the signal is received from the receiver antenna (206). A threshold test is performed on the received signal. If the signal energy is below the specified threshold, the signal is demodulated as bit 0; if it is above it, the signal is demodulated as bit 1. This is due to OOK demodulation (202), because according to OOK demodulation (202), if the signal energy is below the specified threshold, it detects as a noise signal and it means the transmitter has not sent any signal. If the signal energy is above the specified threshold, it means that the transmitter has sent a signal. In this way, the signal is demodulated and added to the bit sequence (101 ). Afterwards, the hopping pattern used is checked. If a linear hopping pattern is used (HP == 0), the carrier frequency is set to the next frequency (n = n+1 ), because in the linear hopping pattern, it is always switched to the next frequency, regardless of the demodulated bit. If the data dependent hopping pattern is used (HP == 1 ), the carrier frequency is switched to the next frequency if the demodulated bit is 1 , because unless the demodulated bit is 1 in the data dependent hopping pattern, the carrier frequency is not set to the next frequency. Then, sub-band control is performed. If the instantaneous sub-band (n) is less than the total sub-band (N), the instantaneous sub-band (n) is not changed, and the signal received from that sub-band is kept in the buffer for correlation and the beginning is started. If the instantaneous sub-band (n) is greater than the total subband (N), the instantaneous sub-band (n) is changed to 1 , because all sub-bands have been scanned. Afterwards, the correlation signal created from the demodulated data bits is correlated with the received signal kept in the buffer. After the correlation, range and velocity estimation is performed and the beginning is started.

[0075] Correlation (208) and range velocity estimation (209) process are explained detail below.

[0076] - For correlation (208), a correlation signal is generated from the demodulated bit sequence (101 ) for each block duration. To perform correlation (208), there is a need to receive a signal, So there is a need to demodulate the bit sequence (101 ) before correlation for each block duration to generate a correlation signal. In normal step carrier techniques, the correlation signal is fixed (pilot-based). In this invention, correlation (208) signal depends on demodulated bit sequence because we use OOK, we cannot send a known pilot series. That explains why there is a need to estimate the correlation signal, that is, the transmitted signal, before correlation.

[0077] - For range velocity estimation (209), comparing the received signal and the correlation signal that is generated from the demodulated bit sequence (101 ), is performed by calculating delay and Doppler with the comparison. In this way, it is easily understand at what speed and distance the signal.

[0078] The proposed stepped carrier On-Off keying method for integrated sensing and communication in THz band is dependent on computer implemented method. The method can be implemented by a processor of network devices for integrated sensing and communication in THz band.

[0079] A computer implemented method of stepped carrier On-Off keying (OOK) for integrated sensing and communication (ISAC) system which is comprising transmitter and receiver in TeraHertz (THz) band wherein the method comprises,

[0080] In transmitter;

[0081] • Receiving bit sequence (101 ) from communication signal and applying to the bit sequence (101 ) for amplitude shift keying modulation by On-Off Keying (OOK) modulation (102), • After OOK modulation (102), passing analog domain by translating the digital information that represents the communication signal into an analog waveform that can be transmitted over the air by Digital to Analog Converter (DAC) (103),

[0082] • Shifting the frequency of a signal baseband frequency to THz frequencies and determining the frequency of the signal by a mixer (104),

[0083] • Providing to deciding that at which carrier frequency to generate a signal by mixer (104) and receiving feedback from bit sequences (101 ) by the frequency synthesizer, determining the center frequency of the signal according to the hopping pattern as linear hopping pattern and data dependent hopping pattern,

[0084] • In the linear hopping pattern, switching the next sub-band linearly at each stage,

[0085] • In the data dependent hopping pattern, if the incoming binary data is 1 , moving to the next sub-band, if the incoming binary data is 0, staying in the same sub-band.

[0086] • If the incoming binary data is one, generating a signal in that sub-band, if zero, no signal is generated,

[0087] • Performing the frequency synthesizer (107) according to the incoming data bits,

[0088] • After performing mixer (104), using High Power Amplifier (HPA) (105) to amplify the signal to determining power level of signal,

[0089] • Sending the signal receiver from the transmitter antenna (106),

[0090] In receiver,

[0091] • After communication starts, receiving the signal by the receiver antenna (206),

[0092] • Performing a threshold test on the received signal by low noise amplifier (LNA) (205), that amplifies the incoming signal at low power,

[0093] • If the received signal energy is below the specified threshold, the received signal is demodulated as bit zero. If the received signal energy is above the specified threshold, the signal is demodulated as bit one, it means that the transmitter has sent a signal. In this way, the signal is demodulated and added to the bit sequence (101 ). This is due to OOK demodulation (202), because according to OOK demodulation (202), if the signal energy is below the specified threshold, it detects as a noise signal and it means the transmitter has not sent any signal. If the signal energy is below the threshold, and if the hopping pattern used is a linear hopping pattern, the carrier signal is adjusted to the next frequency and the beginning is repeating of beginning.

[0094] • Providing the transition from Terahertz frequencies to baseband frequencies by a mixer (104),

[0095] • Deciding which carrier frequency to receive the signal by taking bit sequence (101 ) feedback by frequency sanitizers, if bit sequence (101 ) is one, signal switches to the upper frequency and switches to the signal baseband signal, if bit sequence (101 ) is zero, switching after receiving each signal (In this step, If a linear hopping pattern is used, the carrier frequency is set to the next frequency. If the data dependent hopping pattern is used, the carrier frequency is switched to the next frequency. If the demodulated bit is one, the carrier frequency stays at the same frequency),

[0096] • After switching to baseband frequency, correlation (208) and range velocity estimation (209) are performed for sensing, o For correlation (208),

[0097] - demodulation of bit sequence (101 ) for each block (from the lowest sub-band to the highest sub-band) duration to generate correlation signal, if the received signal is one, it is the received signal is correlated, if the received signal is zero, correlation (208) is not performed (to perform correlation (208), there is a need to receive a signal and demodulate the bit sequence (101 ) before correlation for each block (from the lowest sub-band to the highest sub-band) duration to generate correlation signal. In normal step carrier techniques, the correlation signal is fixed. In communication except OOK, the signal is transmitted every time. OOK also needs to receive correlation (208) bit sequence (101 ) feedback because sometimes the signal is not sent), o For range velocity estimation (209), - comparing the received signal and correlation signal that is generated from the demodulated bit sequence (101 ) by calculating delay and doppler with the comparison to understand speed and distance of the signal,

[0098] • Afterwards, without checking the hopping pattern used, adjusting the carrier frequency to the next frequency and the beginning is started again (this step condition is if only the demodulated bit is one).

[0099] The ADC, which is used to switch from analogue to digital domain in order to On-Off Keying demodulation of the data, looks at the energy of the signal received from the On-Off Keying demodulation. If the energy is below the specified threshold, it means that no signal is sent, the data is demodulated as zero. If it is above the threshold, the data is demodulated as 1 . Because it means that a signal has been sent.

[0100] Based on consideration of the foregoing technical solution, possible embodiments of the invention are as follows;

[0101] • The frequency synthesizer (107) wherein said the frequency synthesizer (107) determines the center frequency according to the hopping pattern.

[0102] • The hopping patterns are linear and data dependent patterns.

[0103] • The frequency synthesizer (107) receives feedback from bit sequences (101 )Carrier frequency has continuously changing frequency which is not constant.

[0104] • The correlation signal is created from the demodulated data bits.

[0105] • The correlation signal is the transmitted signal before correlation.

[0106] • On-Off keying used to receive correlation (208) bit sequence (101 ) feedback.

[0107] • Carrier frequency has continuously changing frequency which is not constant.

[0108] References:

[0109] [1] Elbir, Ahmet M., et al. “Terahertz-band integrated sensing and communications: Challenges and opportunities.” ArXiv preprint arXiv:2208.01235 (2022).

[0110] [2] Han, Chong, et al. “THz ISAC: A physical-layer perspective of terahertz integrated sensing and communication.” ArXiv preprint arXiv:2209.03145 (2022).

[0111] [3] Petrov, Vitaly, Thomas Kurner, and Iwao Hosako. “IEEE 802.15. 3d: First standardization efforts for sub-terahertz band communications toward 6G.” IEEE Communications Magazine 58.11 (2020): 28-33.

[0112] [4] Wu, Yongzhi, et al. “A sensing integrated DFT-spread OFDM system for terahertz communications.” 2021 IEEE 93rdVehicular Technology Conference (VTC2021 -

[0113] Spring). IEEE, 2021.

[0114] [5] Mao, Tianqi, et al. "Waveform design for joint sensing and communications in millimeter-wave and low terahertz bands." IEEE Transactions on Communications 70.10 (2022): 7023-7039.

[0115] [6] Sumen, Gizem, Guneg Karabulut Kurt, and Ali Gbrgin. "A novel Ifm waveform for terahertz-band joint radar and communications over inter-satellite links." GLOBECOM 2022-2022 IEEE Global Communications Conference. IEEE, 2022.

Claims

CLAIMS1 . A computer implemented method of stepped carrier On-Off keying (OOK) for integrated sensing and communication (ISAC) system which is comprising transmitter and receiver in TeraHertz (THz) band wherein the method comprises, In transmitter;• Receiving bit sequence (101 ) from communication signal and applying to the bit sequence (101 ) amplitude shift keying modulation by On-Off Keying (OOK) modulation (102),• After OOK modulation (102), passing analog domain by translating the digital information that represents the communication signal into an analog waveform that can be transmitted over the air by Digital to Analog Converter (DAC) (103),• Shifting the frequency of a signal baseband frequency to THz frequencies and determining the frequency of the signal by a mixer (104),• Providing to decide that at which carrier frequency to generate a signal by mixer (104) and receiving feedback from bit sequences (101) by the frequency synthesizer (107),• Determining the center frequency of the signal according to the hopping patterns linear hopping pattern and data dependent hopping pattern,• In the linear hopping pattern, switching the next sub-band linearly at each band,• In the data dependent hopping pattern,- if the incoming binary data is one, moving to the next sub-band, if the incoming binary data is zero, staying in the same sub-band,- If the incoming binary data is one, generating a signal in that subband, if the incoming binary data is zero, no signal is generated,• Performing the frequency synthesizer (107) according to the incoming data bits,• After performing mixer (104), using High Power Amplifier (HPA) (105) to amplify the signal to determining power level of signal,• Sending the signal to the receiver from the transmitter antenna (106),In receiver,• After communication starts, receiving the sent signal from the transmitter antenna (106) by the receiver antenna (206),• Performing a threshold test on the received signal by low noise amplifier (LNA) (205), that amplifies the incoming signal at low power,• If the received signal energy is below the specified threshold, the received signal is demodulated as bit zero, if the received signal energy is above the specified threshold, the signal is demodulated as bit one,• Providing the transition from TeraHertz frequencies to baseband frequencies by a mixer (104),• Deciding which carrier frequency to receive the signal by taking bit sequence (101 ) feedback by frequency synthesizer (107), o If a linear hopping pattern is used, the carrier frequency is set to the next frequency, o If the data dependent hopping pattern is used, the carrier frequency is switched to the next frequency, o If the demodulated bit is one, the carrier frequency stays at the same frequency,• Performing sub-band (n) control,• If the instantaneous sub-band (n) is less than the total sub-band (N), the instantaneous sub-band (n) is not changed, and the signal received from that sub-band is kept in the buffer for correlation and the beginning is started,• If the instantaneous sub-band (n) is greater than the total sub-band (N), changing the instantaneous sub-band (n) as one,• After switching to baseband frequency, performing correlation (208) and range velocity estimation (209) for sensing, o For correlation (208),- demodulation of bit sequence (101 ) for each from the lowest sub-band to the highest sub-band duration to generate correlation signal, if the received signal is one, the received signal is correlated, if the received signal is zero, correlation (208) is not performed,o For range velocity estimation (209),- comparing the received signal and correlation signal that is generated from the demodulated bit sequence (101 ) by calculating delay and doppler with the comparison to understand speed and distance of the signal,• If only the demodulated bit is one, adjusting the carrier frequency to the next frequency and the beginning is started again without checking the hopping pattern used.

2. The method according to claim 1 , wherein said the transmitter in the method comprises;• At least one On Off Keying modulator (OOK) for OOK modulation (102) which is for applying amplitude shift keying modulation to the bit sequence (101 ),• At least one Digital to Analog Converter (DAC) (103) which is used to translate the digital information that represents the communication signal into an analog waveform that can be transmitted over the air,• At least one mixer (104) is used to shift the frequency of a signal to TeraHertz frequencies,• At least one High Power Amplifier (HPA) (105) which is used to amplify the signal for transmission,• At least one transmitter antenna (106) which sends the signal to receiver,• At least one frequency synthesizer (107) which is provided to determine the center frequency of the signal according to the hopping pattern.

3. The method according to claim 1 , wherein said the receiver in the method comprises;The receiver comprises;• At least one receiver antenna (206) which is received the transmitted signal from transmitter,• At least one Low Noise Amplifier (LNA) (205) which is used to which is used to amplify incoming signals below a certain signal to noise ratio (SNR) value,• At least one mixer (104) is used to shift the frequency of a received signal to baseband frequency,• At least one frequency synthesizer (107) which is used for generating a local oscillator signal at a specific frequency according to the hopping pattern,• Correlator which is providing to performing of apply correlation (208) to signals from different frequencies for sensing,• Range and velocity estimator is performing range velocity estimation (209) according to the results obtained from the correlation (208).

4. The method according to claim, 1 wherein said integrated sensing and communication (ISAC) system comprises;The transmitter in ISAC system comprises• At least one OOK modulator for OOK modulation (102) which is for applying amplitude shift keying modulation to the bit sequence (101 ),• At least one Digital to Analog Converter (DAC) (103) which is used to translate the digital information that represents the communication signal into an analog waveform that can be transmitted over the air,• At least one mixer (104) is used to shift the frequency of a signal to TeraHertz frequencies,• At least one High Power Amplifier (HPA) (105) which is used to amplify the signal to a certain signal to noise ratio (SNR) level to achieve the bit error rate (BER) required for the system,• At least one transmitter antenna (106) which sends the signal to receiver,• At least one frequency synthesizer (107) which is provided to determine the center frequency of the signal according to the hopping pattern.The receiver in ISAC system comprises• At least one receiver antenna (206) which is received the transmitted signal from transmitter,• At least one Low Noise Amplifier (LNA) (205) which is used to which is used to amplify the signal to a certain signal to noise ratio (SNR) level to achieve the bit error rate (BER) required for the system,• At least one mixer (104) is used to shift the frequency of a received signal to baseband frequency,• At least one frequency synthesizer (107) which is used for generating a local oscillator signal at a specific frequency according to the hopping pattern,• Correlator which is providing to performing of apply correlation (208) to signals from different frequencies for sensing,• Range and velocity estimator is performing range velocity estimation (209) according to the results obtained from the correlation (208).

5. The method according to any one of the preceding claims, wherein said the frequency synthesizer (107) receives feedback from bit sequences (101 ).

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