Description:TECHNICAL FIELD
[0001] The embodiments of the present disclosure generally relate to communication system. In particular, the present disclosure relates to a sensing device for sensing an object in an integrated sensing and communication (ISAC) system and a method thereof.

BACKGROUND
[0002] The wireless communication involves data to be transmitted through electromagnetic signals broadcast from sending facilities to intermediate and end-user devices. The wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. In the wireless communication technology, obtaining sensing information from an environment is an important task. With the growing demand for sensing capabilities in fifth generation (5G) and beyond, conserving bandwidth has become critical, prompting the need for integrated sensing and communication (ISAC) or joint communication and sensing (JCAS) based solutions.
[0003] For effective integrated sensing and communication, the sensing system, i.e., a base station (BS) or gNodeB itself is used as the collocated, monostatic, and active sensing system, and must align with the existing communication technology and waveform used. Utilizing 5G New Radio (NR) signal for sensing presents significant challenges, requiring extensive study and research for performance as well as resource optimization. Sensing in the sub-6 GHz band is inherently complex and further integrating it with communication adds additional complexity. Specifically, using 5G NR Synchronization Signal Block (SSB) signals for sensing faces obstacles such as limited coverage, low range, and poor resolution, while meeting system power requirements without sacrificing communication.
[0004] The use of 5G NR SSB signals for sensing and for enhancing range and resolution for high confidence level while maintaining system power levels intact is critical. The existing solutions fail to overcome this critical aspect. Additionally, addressing the power leakage between a transmission antenna and a reception antenna in a collocated sensing device is a challenging task.
[0005] There is, therefore, a need for an effective ISAC solution for 5G and beyond which overcomes the above limitations and provides an optimal solution. For example, there is a need for a system and a method for adaptive sensing for integrated sensing and communication using 5G NR synchronization signal to identify an object with good confidence level.

OBJECTS OF THE PRESENT DISCLOSURE
[0006] An object of the present disclosure is to provide a system and a method for adaptive sensing for integrated sensing and communication, and determining a distance of an object from a sensing device.
[0007] Another object of the present disclosure is to provide a system and a method that enhances a range and a resolution for high confidence level in a form of high probability of correctness, and reduces a probability of false alarm while maintaining system power levels intact.
[0008] Another object of the present disclosure is to provide a system and a method that addresses a power leakage between a transmission antenna and a reception antenna in a collocated sensing device.
[0009] Another object of the present disclosure is to ensure improved performance in the sensing device, and resource optimization.

SUMMARY
[0010] This section is provided to introduce certain objects and aspects of the present disclosure in a simplified form that are further described below in the detailed description. This summary is not intended to identify the key features or the scope of the claimed subject matter.
[0011] In an aspect, the present disclosure relates to a method for sensing an object in an integrated sensing and communication (ISAC) system. The method includes transmitting, by a sensing device, a sensing signal. The transmitted sensing signal is stored in a first buffer associated with the sensing device. The method includes receiving, by the sensing device, a reflected signal, corresponding to the transmitted sensing signal, from the object. Further, the method includes filtering, by the sensing device, the reflected signal to obtain a filtered reflected signal. The method includes determining, by the sensing device, an identifier corresponding to the filtered reflected signal by executing a cross-correlation function between the transmitted sensing signal, obtained from the first buffer, and the filtered reflected signal. Furthermore, the method includes determining, by the sensing device, that the identifier corresponding to the filtered reflected signal is same as that of the sensing device. In response to a determination that the identifier is the same, the method includes determining, by the sensing device, a round trip delay of the sensing signal based at least on the cross-correlation function, and a difference between a timestamp at the transmission of the sensing signal and a timestamp at the reception of the reflected signal.
[0012] In an embodiment, the sensing signal may include a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). The sensing device may be a collocated, monostatic, and active sensing device.
[0013] In an embodiment, the method may include configuring, by the sensing device, a Boolean logic to true, for two alternate Orthogonal Frequency Division multiplexing (OFDM) symbol duration, in response to the transmission of the sensing signal. The method may include configuring, by the sensing device, the Boolean logic to false to block transmission of other signals by the sensing device.
[0014] In an embodiment, the identifier may correspond to a Physical Cell Identifier (PCI) of the sensing device. The PCI may be calculated based on the PSS and the SSS.
[0015] In an embodiment, the method may include comparing, by the sensing device, a peak value of the cross-correlation function with a pre-defined threshold value stored in a second buffer associated with the sensing device. In response to a determination that the peak value is less than the pre-defined threshold value, the method may include redistributing, by the sensing device, power across Physical Resource Elements (PREs) in one of a plurality of configurations. In response to a determination that the peak value is greater than the pre-defined threshold value, the method may include determining, by the sensing device, a confidence level of the cross-correlation function, where the confidence level may be based on a degree to which the peak value surpasses the pre-defined threshold value.
[0016] In an embodiment, the redistributing may include sending, by the sensing device, a first request to a higher layer to allocate additional PREs in one of a single Orthogonal Frequency Division Multiplexing (OFDM) symbol, multiple OFDM symbols within same OFDM slot, or a single PSS OFDM symbol. In response to the request, the method may include, receiving, by the sensing device, a notification on the allocated additional PREs from the higher layer. Further, the redistributing may include transmitting, by the sensing device, an enhanced sensing signal in the additional PREs in one of the plurality of configurations. The redistributing may include receiving, by the sensing device, an enhanced reflected signal, corresponding to the transmitted enhanced sensing signal, from the object. Furthermore, the redistributing may include determining, by the sensing device, a sensing sequence identifier (SSI) corresponding to the enhanced reflected signal by executing the cross-correlation function between the transmitted enhanced sensing signal and the enhanced reflected signal. The redistributing may include determining, by the sensing device, whether the SSI is same as that of the sensing device.
[0017] In an embodiment, in response to a determination that the SSI is the same, the method may include determining, by the sensing device, whether an enhanced peak value of the cross-correlation function is greater than the pre-defined threshold value. Further, in response to a determination that the SSI is not the same, the method may include continuing, by the sensing device, the transmission of the enhanced sensing signal.
[0018] In an embodiment, in response to a determination that the enhanced peak value is less than the pre-defined threshold value, the method may include sending, by the sensing device, a second request to the higher layer to allocate the additional PREs with additional OFDM symbols within an OFDM slot. In response to a determination that the enhanced peak value is greater than the pre-defined threshold value, the method may include, determining, by the sensing device, the confidence level of the cross-correlation function.
[0019] In an embodiment, in response to determining, by the sensing device, the confidence level, the method may include determining, by the sensing device, whether the confidence level is greater than a minimum confidence level corresponding to a sensing zone of the sensing device. In response to a determination that the confidence level is less than the minimum confidence level, the method may include allocating, by the sensing device, additional PREs in a Physical Downlink Shared Channel (PDSCH), or increasing, by the sensing device, the allocation of the additional PREs in the additional OFDM symbols. Further, in response to a determination that the confidence level is greater than the minimum confidence level, the method may include determining, by the sensing device, the round-trip delay of the sensing signal and a range of the object from the round-trip delay.
[0020] In an embodiment, the enhanced sensing signal may include a first ranging sequence and a second ranging sequence, each having a variable length. The SSI may be calculated based on the first ranging sequence and the second ranging sequence.
[0021] In one embodiment, the plurality of configurations may include allocation of the additional PREs in a single OFDM symbol, where the enhanced sensing signal is a 126-length frequency-domain sequence, and each of the first ranging sequence and the second ranging sequence of the enhanced sensing signal has 63-length. The plurality of configurations may include allocation of the additional PREs in two OFDM symbols, where the enhanced sensing signal is a 126-length frequency-domain sequence, and each of the first ranging sequence and the second ranging sequence of the enhanced sensing signal has 63-length. Further, the plurality of configurations may include allocation of the additional PREs in four OFDM symbols, where the enhanced sensing signal is a 126-length frequency-domain sequence, and each of the first ranging sequence and the second ranging sequence of the enhanced sensing signal has segments of 63-length, each segment having sequences of 31 and 32-length. Furthermore, the plurality of configurations may include allocation of the additional PREs in a single OFDM symbol, where the enhanced sensing signal is a 62-length frequency-domain sequence. The plurality of configurations may include allocation of the additional PREs in two OFDM symbols, where the enhanced sensing signal is a 62-length frequency-domain sequence, and each of the first ranging sequence and the second ranging sequence of the enhanced sensing signal has 31-length. The plurality of configurations may include allocation of the additional PREs in four OFDM symbols, where the enhanced sensing signal is a 62-length frequency-domain sequence, and each of the first ranging sequence and the second ranging sequence of the enhanced sensing signal has segments of 31-length, each segment having sequences of 15 and 16-length.
[0022] In one embodiment, the method may include determining, by the sensing device, a colliding probability factor corresponding to a probability of collision of signals from another sensing device. The colliding probability factor may be a ratio of a length of the sensing signal to a length of the enhanced sensing signal. The method may include transmitting, by the sensing device, the enhanced sensing signal in said one of the plurality of configurations based on the colliding probability factor.
[0023] In an embodiment, the method may include eliminating, by the sensing device, a signal coupling between the transmitted sensing signal and the received sensing signal.
[0024] In an aspect, the present disclosure relates to a sensing device for sensing an object in an integrated sensing and communication system. The system includes a processor, and a memory operatively coupled with the processor. The memory stores instructions which, when executed by the processor, cause the device to transmit a sensing signal toward an object. The transmitted sensing signal is stored in a first buffer associated with the sensing device. The device is configured to receive a reflected signal, corresponding to the transmitted sensing signal, from the object. The device is configured to filter the reflected signal to obtain a filtered reflected signal, and determine an identifier corresponding to the filtered reflected signal by executing a cross-correlation function between the transmitted sensing signal, obtained from the first buffer, and the filtered reflected signal. Further, the device is configured to determine whether the identifier corresponding to the filtered reflected signal is same as that of the sensing device. In response to a determination that the identifier is the same, the device is configured to determine a round trip delay of the sensing signal based at least on the cross-correlation function, and a difference between a timestamp at the transmission of the sensing signal and a timestamp at the reception of the reflected signal. In response to a determination that the identifier is not the same, continue to receive the reflected signal from the object.

BRIEF DESCRIPTION OF DRAWINGS
[0025] The accompanying drawings, which are incorporated herein, and constitute a part of this invention, illustrate exemplary embodiments of the disclosed methods and systems in which like reference numerals refer to the same parts throughout the different drawings. Components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Some drawings may indicate the components using block diagrams and may not represent the internal circuitry of each component. It will be appreciated by those skilled in the art that the invention of such drawings includes the invention of electrical components, electronic components, or circuitry commonly used to implement such components.
[0026] FIG. 1A illustrates an example system architecture (100A) of a monostatic sensing system with co-located antennas, in accordance with an embodiment of the present disclosure.
[0027] FIG. 1B illustrates an example system architecture (100B) for enhanced integrated sensing and communication for an object, respectively, in accordance with an embodiment of the present disclosure.
[0028] FIGs. 2A-2B illustrate flow charts of an example method (200A-200B) for integrated sensing and communication, in accordance with an embodiment of the present disclosure.
[0029] FIG. 3 illustrates an exemplary structure (300) of a synchronization signal block (SSB), in accordance with an embodiment of the present disclosure.
[0030] FIG. 4 illustrates a schematic representation (400) of a primary synchronization sequence (PSS) and a secondary synchronization sequence (SSS) in a resource grid, in accordance with the embodiments of the present disclosure.
[0031] FIG. 5 illustrates a schematic representation (500) of the PSS and a cross-correlation for different network identities (NIDs), in accordance with an embodiment of the present disclosure.
[0032] FIGs. 6-8 illustrate schematic representations (600-800) representing additional Physical Resource Elements (PREs) in a resource grid, in accordance with embodiments of the present disclosure.
[0033] FIG. 9 illustrates a schematic representation (900) depicting additional PREs allocated in a single PSS Orthogonal Frequency Division multiplexing (OFDM) symbol of the resource grid, in accordance with an embodiment of the present disclosure.
[0034] FIG. 10 illustrates a schematic representation (1000) depicting an object detection and a confidence zone classification.
[0035] FIG. 11 illustrates a schematic representation (1100) depicting windowing analogue to digital converter (ADC) output with a cyclic prefix (CP) for calulating a round trip delay, in accordance with an embodiment of the present disclosure.
[0036] FIG. 12 illustrates a block diagram (1200) representing a sensing device for sensing an object in an integrated sensing and communication (ISAC) system, in accordance with an embodiment of the present disclosure.
[0037] The foregoing shall be more apparent from the following more detailed description of the invention.

DETAILED DESCRIPTION OF INVENTION
[0038] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features. An individual feature may not address all of the problems discussed above or might address only some of the problems discussed above. Some of the problems discussed above might not be fully addressed by any of the features described herein.
[0039] Various embodiments of the present disclosure will be explained in detail with reference to FIGs. 1-12.
[0040] FIG. 1A illustrates an example system architecture (100A) of a monostatic sensing device (102) with co-located antennas, in accordance with an embodiment of the present disclosure. In an embodiment, the sensing device (102) may be a monostatic and active sensing device including, but not limited to, a base station, a gNodeB, an eNodeB, or the like. In the monostatic and the active sensing device (102), a transmitting (Tx) antenna (108) and a receiving (Rx) antenna (112) are collocated. In an embodiment, the sensing device (102) may include an isolator (110) to facilitate an isolation between the Tx antenna (108) and the Rx antenna (112) for preventing power leakage through a plurality of arrangements. In an embodiment, the plurality of arrangements may include maximizing a distance between the Tx antenna (108) and the Rx antenna (112), employing an electromagnetic shield between the Tx antenna (108) and the Rx antenna (112), utilizing highly directive antennas, and the like.
[0041] In an embodiment, the position of the Tx antenna (108) and the Rx antenna (112) may be kept apart and the antennas may be adjusted to minimize a direct line-of-sight coupling. In an aspect, back-to-back placement of the Tx antenna (108) and the Rx antenna (112) may be considered, where the Rx antenna (112) faces away from the Tx antenna (108) to significantly reduce power leakage. In an embodiment, the electromagnetic shielding may be employed by using one or more electromagnetic shielding materials or structures. The electromagnetic shielding between the Tx antenna (108) and the Rx antenna (112) may be structured to absorb or reflect unwanted signals, and thereby reducing a leakage path. In an embodiment, highly directive antennas may be utilized as the Tx antenna (108) and the Rx antenna (112) and may facilitate to focus the signals and minimize the power leakage.
[0042] Referring to FIG. 1A, a sensing signal (114) may be transmitted from the Tx antenna (108), for example, to an object (104). In an embodiment, the object (104) may include, but not limited to, a vehicle, a pedestrian, an intruder, or the like. The Rx antenna (112) may receive a reflected signal (116) from the object (104), which may be referred to as the desired reflected signal (116). However, as shown, the Rx antenna (112) may also receive unwanted signals (118) from another sensing device (e.g., gNodeB) (106).
[0043] FIG. 1B illustrates an example system architecture (100B) for integrated sensing and communication for an object (104), in accordance with an embodiment of the present disclosure.
[0044] Referring to FIG. 1B, the sensing device (102) may include a waveform generator (120), a Boolean logic entity (122), a first buffer (124), a correlator (126), a second buffer (128), a Rx block (130), and a Tx block (132). In an embodiment, the waveform generator (120) may be used to create and test waveforms used in a fifth generation (5G) New Radio (NR) communication system. The waveform generator (120) may be critical for developing, testing, and validating the 5G technology. The waveform generator (120) may also ensure compliance with standards and optimize the performance of the system. In an embodiment, the waveform generator (120) may produce a variety of waveforms required for 5G NR, including a plurality of physical layer signals and a plurality of channels specified by the compliant standards, for example, 3GPP standards. The waveforms may be used for uplink and downlink communication. In an embodiment, the waveform generator (120) may be configured to produce a sensing signal. In an embodiment, the waveform generator (120) may produce a 5G NR Synchronization Signal Block (SSB) signal and a Physical Downlink Shared Channel (PDSCH).
[0045] In an embodiment, the Boolean logic (122) may enable transmitted Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) or PDSCH signal to correlate with reflected PSS and SSS or PDSCH signal. The reflected signal may be received from the object (104). The correlation may be performed for two alternate orthogonal frequency-division multiplexing (OFDM) symbols duration for the PSS and the SSS, and one OFDM symbol duration for the PDSCH, while blocking other 5G NR signals. In an embodiment, when the Tx block (132) in the sensing device (102) sends the sensing signal (e.g., 5G NR signals such as PSS or SSS or PDSCH signal), the Boolean logic becomes true, i.e. YES or logic 1, and may pass the transmitted sensing signal. In an embodiment, when the Tx block (132) sends other signals instead of the sensing signal, the Boolean logic becomes false, i.e., NO or logic 0, and may block the other signals.
[0046] In an embodiment, the Tx block (132) may be responsible for sending the sensing signal over the air to receivers. The Tx block (132) may include a binary phase shift keying (BPSK) modulator, a Serial-to-Parallel conversion (S/P), an inverse fast Fourier transform (IFFT), a Cyclic Prefix addition, a Parallel-to-Serial conversion (P/S), a digital-to-analogue converter (DAC), etc.
[0047] In an embodiment, the Tx antenna (108) may operate at high frequencies to provide high bandwidth and better resolution for sensing applications. For example, operating at a central frequency of 4 GHz with a bandwidth of 400 MHz may enable precise indoor object localization and tracking of the object (104). Further, the Rx antenna (112) may be designed with high sensitivity and low noise characteristics to accurately capture the reflected signals from the object (104). As the Rx antenna (112) is highly sensitive, it is critical to extract meaningful sensing data from noisy signals. In an embodiment, if the sensitivity of the Rx antenna (112) is higher than the minimum detectable power level of the reflected signal, the performance of the Rx antenna (112) may be improved.
[0048] Referring to FIG. 1B, in an embodiment, the Rx block (130) receives the desired reflected signal (116) from the object (104) as well as other unwanted signals (118) from other sensing device (106) via the Rx antenna (112). In an embodiment, another sensing device (106) such as gNodeB as shown in FIG. 1B, may be present in the vicinity of the sensing device (102) which may act as a source of unwanted signal (118), creating an interference to the desired signal (116). The Rx block (130) processes the received reflected signals for filtering the noise from the received reflected signals and produce filtered reflected signals. For example, key components and functions of the Rx block (130) may include analogue to digital converter (ADC), S/P, Cyclic Prefix removal, Fast Fourier Transform (FFT), P/S, and BPSK de-modulator.
[0049] In an embodiment, the sensing device (102) includes the first buffer (124). It may be appreciated that the first buffer (124) may be interchangeably referred to as a delay block, which is responsible for compensating all processing delays within the sensing device (102), excluding round-trip delay. In an embodiment, the first buffer (124) stores the sensing signal, for example, the PSS, the SSS, and the PDSCH transmitted from the Tx antenna (108).
[0050] In an embodiment, the correlator (126) is adapted to measure the similarity between two signals, for example, the predefined stored sensing signal in the first buffer (124) and the reflected sensing signal from the object (104) by performing cross-correlation. In an embodiment, the cross-correlation involves multiplication of corresponding samples from two signals, followed by the integration (or summation) of the products obtained from the multiplication over time. The correlator (126) produces the cross-correlation function, which depends on time samples. The correlator (126) may determine an identifier corresponding to the reflected signal (or filtered reflected signal) by executing the cross-correlation function between the transmitted sensing signal, obtained from the first buffer (124), and filtered reflected signal. In an embodiment, the sending device (102) may determine whether the identifier is same as that of the sensing device (102).
[0051] Further, in an embodiment, the second buffer (128) may be referred to as a decision block. The decision block (128) may determine a round trip delay of the sensing signal based at least on the cross-correlation function, and a difference between a timestamp at the transmission of the sensing signal and a timestamp at the reception of the reflected signal. In an embodiment, the decision block (128) may identify a peak value of the cross-correlation function between the transmitted sensing signal and the reflected signal from the object (104). Further, the decision block (128) calculates a confidence level based on the peak value. In an embodiment, the decision block (128) includes a pre-defined threshold value (?) with an associated confidence level for comparing the peak value (?’) of the cross-correlation function between the transmitted sensing signal and the reflected signal from the object (104) with radar cross section (RCS) s. The confidence level is expressed in terms of Excess Value (EV), which is defined as the percentage by which the obtained cross-correlation function peak value exceeds the pre-defined threshold value set by the decision block (128). In an embodiment, the confidence level may be calculated as:
Excess value (%) = ( × 100) %
[0052] Further, the decision block (128) determines the round trip delay of the sensing signal by calculating the difference between the timestamp at the transmission of the sensing signal and the timestamp at the reception of the sensing signal if the confidence level is in sensing zone.
[0053] FIGs. 2A and 2B illustrate flow charts of an example method (200A, 200B) for integrated sensing and communication, in accordance with an embodiment of the present disclosure.
[0054] At step (201), the method (200A) includes transmitting, by a sensing device (e.g., 102), a sensing signal. The transmitted sensing signal is stored in a first buffer (e.g., 124) associated with the sensing device (102). In an embodiment, the sensing signal may be a 5G NR synchronization signal (PSS and SSS). Further, the sensing device (102) is a collocated, monostatic, and active sensing device for a pre-defined sensing zone (range), which is always smaller than the cell edge of the base station (sensing system). It may be appreciated that the sensing zone is dependent on the rated carrier output power for various base station (BS). 3GPP TS 38.104, section 6.2.1 defines BS rated power for different BS class as:

[0055] In an embodiment, 5G NR synchronization signal may serve as a sensing signal. There are two primary types of synchronization signals: Primary Synchronization Signal (PSS) and the Secondary Synchronization Signal (SSS) which is a part of SSB (Synchronization Signal Block). FIG. 3 depicts the SSB structure as defined in the 3GPP standard. The PSS is mapped to 127 active sub-carriers around the center of the synchronization signal block (SSB) and uses a 127 m-sequence for its generation. The PSS is transmitted in specific OFDM symbols. It helps to acquire symbol timing. In 5G NR, the PSS can be transmitted in various subframes depending on the configuration. Typically, the PSS appears in the first OFDM symbol of the SSB. Further, like the PSS, the SSS is also mapped to a central band of sub-carriers within the SSB. It provides additional synchronization and cell identity information. The SSS is transmitted with a time offset from the PSS. In 5G NR, the SSS is not consecutive with the PSS but separated in time by one OFDM symbol, which typically includes the Physical Broadcast Channel (PBCH) in between.
[0056] During the initial transmission phase, assuming the sensing device (102) transmits the PSS/SSS symbol using the rated carrier output power as specified in above tables. The PSS/SSS symbol power is the average power of all resource elements within the PSS/SSS symbol. FIG. 4 depicts the location of PSS and SSS in resource grid for one slot which can be further utilized for PCI calculation and for target sensing purpose.
[0057] As an example, power required to transmit PSS and SSS symbol may be calculated as: for 100 MHz channel bandwidth, there are 127 Physical Resource Elements (PREs). Considering the channel power of 24 dBm (251.189 mW) for a local area base station, it means total power for transmitted PSS/ SSS symbol is 24 dBm (251.189 mW). In PSS/ SSS symbol, total number of Resource Elements = 127. Power per Resource Element = 251.189 mW/ 127 = 1.978 mW = 2.962 dBm.
[0058] Referring to FIG. 2A, at step (202), the method (200A) includes receiving, by the sensing device (102), a noisy reflected signal, corresponding to the transmitted sensing signal, from the object (e.g., 104). The power of the reflected PSS/SSS signal depends on the object’s RCS value. Different targets with predefined RCS values are provided in ETSI TR 103 593V1.1.1.C3 as:

[0059] At step (203), the method (200A) includes retrieving and filtering, by the sensing device (102), the reflected signal, i.e. the noisy (AWGN) reflected signal, for example, in Rx block (e.g., 130) to obtain a filtered reflected signal. In an embodiment, retrieving the PSS and the SSS signal in the Rx block (130) involves steps such as signal reception, additive white Gaussian noise (AWGN) filtering, analogue to digital converter (ADC) conversion, removal of the Cyclic Prefix, Serial-to-Parallel conversion (S/P), Inverse Fast Fourier Transform (IFFT), Parallel-to-Serial conversion (P/S), and demodulation. As the reflected signal is corrupted by AWGN, the reflected signal is filtered to eliminate the noise. In an embodiment, the methods to filter AWGN from reflected PSS and reflected SSS signals include Matched Filtering, Wavelet Transform, Gaussian Filtering, Exponential Smoothing, and the like.
[0060] At step (204), the method (200A) includes activating a Boolean logic for two alternate OFDM symbol duration for allowing processing of the sensing signal. In an embodiment, Boolean logic is a function of time which is used to pass the PSS / SSS signal and to block other sensing signals. In an embodiment, when a Tx block (e.g., 132) in the sensing device (102) sends the PSS signal and the SSS signal as sensing signal, the Boolean logic becomes true, and passes the transmitted PSS and the SSS signal. In another embodiment, when the Tx block (132) sends other signal instead of the sensing signal, the Boolean logic becomes false, and blocks another sensing signal.
Boolean logic BL(t) is ON for one OFDM Symbol duration represented as:
B(t) = 1;
Boolean logic BL(t) is OFF for Other OFDM Symbols duration is represented as: B(t) = 0; }
Where, is a Symbol Duration,
the PSS / SSB signal
[0061] The PSS and SSS signals are then stored in the first buffer (124). The first buffer (124) accounts for processing delays throughout the sensing device (102), which encompasses delays from Boolean logic (122), Tx antenna (108), Rx antenna (112), Rx block (130), noise filtering block, and correlator (126). It may be noted that round trip delay is excluded from the buffer delay.
[0062] Referring to FIG. 2A, at step (205), the method (200A) includes executing cross-correlation function between the transmitted sensing signal and the filtered reflected signal of a pre-defined periodicity, for example, 20 ms. After receiving the filtered reflected signal, which includes reflections from the object (104) with RCS s, the correct sensing signal is evaluated by performing the cross-correlation between the filtered reflected signal and the pre-existing sensing signal stored in the first buffer (124). For example, if there are three PSS, the received signal may be correlated with these three PSS, generated from m-sequences of length 127. To identify the correct PSS, cross-correlations may be performed and peaks may be identified in the cross-correlation output. The highest peak value may indicate the correct PSS. The SSS sequence may also be cross-correlated with all possible SSS sequences, which are combinations of sequences derived from, for example, Zadoff-Chu sequences.
[0063] At step (206), the method (200A) includes determining, by the sensing device (102), an identifier corresponding to the filtered reflected signal by executing the cross-correlation function between the transmitted sensing signal, obtained from the first buffer, and the filtered reflected signal. In an embodiment, the identifier may be Physical Cell Identifier (PCI). The PSS detection gives (NID2) which is an integer that can be 0, 1, or 2. The SSS detection gives (NID1) which is an integer ranging from 0 to 335. The PCI is then computed as:
PCI = 3× +
Where;
is derived from the SSS, and is derived from the PSS.
For instance, if and the PCI value is,
PCI = 3 × 200 +1 = 601
[0064] At step (207), the method (200A) includes determining, by the sensing device (102), whether the identifier corresponding to the filtered reflected signal is same as that of the sensing device (102). The base station functions as a sensing system, linked to a PCI out of 1008 options. Initially, the sensing device (102) possesses knowledge of its PCI. Upon retrieving the reflected signal, the sensing device (102) obtains NID1 and NID2 values, which determine the PCI value. If the calculated PCI matches the pre-defined PCI of the sensing device (102), it confirms that the reflected signal corresponds to the desired one (e.g., 116). If the calculated PCI does not match the pre-defined PCI of the sensing device (102), it confirms that the reflected signal corresponds to the unwanted signal (e.g., 118) from other base stations, gNodeBs, or the like. Under such circumstances, the sensing device (102) halts its operations for additional processing and captures the distorted reflected signal (resulting from the object’s RCS s), which corresponds to the transmitted sensing signal.
[0065] Referring to FIG. 2A, at step (208), the method (200A) includes determining, by the sensing device (102), if a peak value of the cross-correlation function is greater than a pre-defined threshold value. At step (209), a minimum threshold is set for the peak value of the cross-correlation function and stored in the second buffer (e.g., 128). This threshold may be denoted as (?). For example, in a specific case, as depicted in FIG. 5, the threshold (?) is set to 0.7 or 70%. After correlating the transmitted PSS ( ) with the predefined PSS values for = 0, 1, and 2, the decision block (128) estimates the PSS for which the cross-correlation function peak value exceeds 0.7 or 70%. In this scenario, the cross-correlation function peak value for is above 70%, so the decision block (128) identifies the PSS corresponding to . If the peak value of the cross-correlation function exceeds the threshold (?), the object’s range can be detected, but associated with a certain level of confidence in the sensing process. The degree to which the peak value surpasses the threshold value (?) determines the confidence level. If the peak value of the cross-correlation function is below the threshold (?), the object’s range cannot be detected. In such cases, the method includes redistributing power across different PREs in a varied manner, i.e., in one of a plurality of configurations.
[0066] Referring to FIG. 2B, if the peak value of the cross-correlation function is lower than the threshold value, then at step (214), the method (200B) includes sending a first request to a higher layer for allocating additional PREs for new defined enhanced sensing signal. In an embodiment, the PREs may be allocated either in a single OFDM symbol or multiple OFDM symbols within same OFDM slot (N-PREs). If the peak value of the cross-correlation function is below the threshold (?), the object’s range cannot be detected. This may be due to poor channel conditions leading to a low Signal to Noise Ratio (SNR) or insufficient power of the transmitted sensing signal to cover the intended sensing zone. Since channel conditions cannot be controlled, the only option is to effectively increase the power level PREs which can be used in the sensing signal. Sending the PSS symbol for 127 PREs as a sensing signal is insufficient in such cases. Therefore, the sensing device (102) requests the higher layer to allocate additional PREs to design a new enhanced sensing signal with a higher power level compared to the previous signal. In an embodiment, the enhanced sensing signal may include a first Ranging Sequence-1 (RS-1) and a second Ranging Sequence-2 (RS-2), which may be variable length sequence of Zadoff-Chu sequence, as an example. Further, a Sensing Sequence Identifier (SSI), which is calculated by RS-1 and RS-2, identifies whether the enhanced sensing signal reflected from object (104) comes from the point of the interest sensing device (102) or other gNodeBs (106), along with some collision probability factors of other gNodeBs (106). The colliding probability factor decreases with the length of the sequence of RS-1 and RS-2. In 5G NR, there are 1008 unique PCIs, so the SSI may also be 1008 to effectively differentiate between gNodeBs. Similar to the 1008 values of PCI in 5G NR, SSI may also differentiate between 1008 gNodeBs, meaning the SSI values range from 0 to 504 (or 252). Mathematically;
SSI = 3 × +
Where;
is derived from the RS-1, and is derived from the RS-2. Where RSI is Ranging Sequence Index.
The value of is an integer ranging from 0 to 167 (or 83)
The value of is an integer that can be 0, 1, or 2.
[0067] In an embodiment, 1, 2, and 4 OFDM symbols may be used for enhanced sensing signals, employing ZC sequences of different lengths. RS-1 and RS-2 are mapped according to the ZC sequence length and the OFDM symbol used.
[0068] Initially, PSS and SSS (each with a length of 127 ZC sequences) are used for PCI calculation, with PSS also serving as the sensing signal. For enhanced sensing, a power boost is required. RS-1 and RS-2 (each with lengths of 63 or 31) are used, arranged in different configurations of allocated PREs within either 2 or 4 OFDM symbols. Both RS-1 and RS-2 are needed for SSI calculation and enhanced sensing signals.
[0069] When the ZC length is shorter, fewer additional PREs are needed. If these are distributed across multiple OFDM symbols, the EPRE increases, thus enhancing the sensing power. However, there is a drawback in the form of interference from other gNodeBs, increasing the likelihood of missing unwanted signals from these gNodeBs. To address this, an associated colliding probability factor is introduced, indicating the efficiency of the proposed configuration in differentiating unwanted signals from other gNodeBs in terms of SSI. The colliding probability factor (?) is the ratio of the length of ZC sequences used for PCI calculation (total length of PSS and SSS) to the length of ZC sequences used for SSI calculation (total length of RS-1 and RS-2). Mathematically;
Colliding probability factor (?) = Chance of colliding of other gNodeBs
[0070] There are six type of configurations based on the length of the ZC sequence used as the sensing signal and the number of OFDM symbols used for allocating new PREs, as shown below.
Proposed Plan Number Zadoff-Chu Sequence Length (N) = Allocating new PREs Number of OFDM Symbol Power Boost (dB) Colliding Probability Factor
(?)
1 126 (63+63) 1 0 1/2
2 126 (63+63) 2 3 1/2
3 126 (31+32+31+32) 4 6 1/2
4 62 (31+31) 1 3 3/4
5 62 (31+31) 2 6 3/4
6 62 (15+16+15+16) 4 9 3/4

[0071] Configuration Plan 1: Additionally, allocating PREs in a single OFDM symbol and the new enhanced sensing signal is a 126 (63+63)-length ZC sequence. This sequence is divided into two parts: 63-length for RS-1 and 63-length for RS-2, both transmitted within the same OFDM symbol. Initially, a 127-length ZC sequence is used for PSS and SSS for PCI (0 to 1008) calculation, with PSS also used for sensing. In the new approach, RS-1 and RS-2, each 63-length ZC sequences, are used for SSI (0 to 1008) calculation and both for sensing. While the ZC sequence length for sensing remains the same, the sequence length for SSI calculation is reduced. The same is depicted in representation (600) of FIG. 6.
[0072] Configuration Plan 2: Additionally, allocating PREs in two OFDM symbols and the new enhanced sensing signal is a 126 (63+63)-length ZC sequence. This sequence is split into two segments: 63-length for RS-1 and 63-length for RS-2, with each segment transmitted in different two consecutive OFDM symbols. In this configuration plan, both sequences RS-1 and RS-2 are used for SSI calculation and sensing. The same is depicted in representation (700) of FIG. 7.
[0073] For example, with a 100 MHz channel bandwidth, considering the channel power of 24 dBm (251.189 mW) for an AISC 2T2R small cell base station. It means total transmitted power for enhanced sensing signal may be calculated as;
Total transmitted power for enhanced sensing signal
= (Power transmitted in RS-1 symbol + Power transmitted in RS-2 symbol)
= (251.189 + 251.189) Mw
= 502.378 Mw
= 27.010 dBm
= 27 dBm (approximately)
So power boost up in this configuration plan
= (27 – 24) dBm
= 3 dBm
[0074] Configuration Plan 3: Additionally allocating PREs in four OFDM symbols and the new enhanced sensing signal is a 126 (31+32+31+32)-length ZC sequence. This sequence is divided into two segments: 63-length for RS-1 and 63-length for RS-2. Each 63-length segment is further divided into sequences of 31 and 32 lengths, respectively, with each sequence transmitted in four different consecutive OFDM symbols. The same is shown in representation (800) of FIG. 8.
[0075] For example, with a 100 MHz channel bandwidth, considering the channel power of 24 dBm (251.189 mW) for an AISC 2T2R small cell base station. It means total transmitted power for enhanced sensing signal can be calculated as;
Total transmitted power for enhanced sensing signal
= (Power transmitted in RS-1 symbols + Power transmitted in RS-2 symbols)
= {(2 × 251.189) + (2 × 251.189)} mW
= 1004.756 mW
= 30.021 dBm
= 30 dBm (approximately)
So power boost up in this configuration plan
= (30– 24.000) dBm
= 6dBm
[0076] Configuration Plan 4: Additionally allocating PREs in a single OFDM symbol and the new enhanced sensing signal is a 62-length ZC sequence.
[0077] Configuration Plan 5: Additionally allocating PREs in two OFDM symbols and the new enhanced sensing signal is a 62 (31+31)-length ZC sequence.
[0078] Configuration Plan 6: Additionally allocating PREs in four OFDM symbols and the new enhanced sensing signal is a 62 (15+16+15+16)-length ZC sequence.
[0079] Alternatively, in another embodiment, at step (214), the method (200B) includes sending the first request to higher layer for allocating additional PREs for new defined sensing signal in single PSS OFDM symbol (M-PREs). Allocating additional PREs in the single PSS OFDM symbol, different from the standard 127 PREs of PSS, poses certain challenges. The allocation must ensure that the additional PREs do not interfere with the primary function of the PSS or disrupt the null PREs. In this manner, two ZC sequences of 63 length are used as the RS-1 and RS-2 to retrieve and for SSI calculation. FIG. 9 shows a representation (900) depicting how the additional PREs are allocated in single PSS OFDM symbol for sensing signal power boost up to enhance range / resolution.
[0080] The below calculation depicts the power boost up of sensing signal with 4.76 dBm as an example: For example, with a 100 MHz channel bandwidth, there are 3276 Physical Resource Elements (PREs). Considering the channel power of 24 dBm (251.19 mW) for an AISC 2T2R small cell base station.
So, power per Resource Element = 251.19 mW/ 3276 = 0.0766758241mW = -11.16 dBm
PSS/ SSS symbol EPRE = -11.16 dBm
In new sensing signal, for PSS PREs and additional allocated PREs, the total number of Resource Elements = 127 + N
Total power for transmitted new sensing signal = (0.0766758241mw) × (127 + N)
= (9.73782966 +0.0766758241 N) mW
For example, minimum additional allocated PREs (N) = 126
So total power for transmitted new sensing signal = (9.73782966 +0.0766758241 × 126) mW
= (9.73782966 +19.3989834966) mW
= 29.1368131566 mW
= 14.64 dBm
Therefore, power increase for new sensing signal as compared to previous sensing signal
= (14.64- 9.88) dBm
= 4.76 dBm
[0081] Referring to FIG. 2B, at step (215), the method (200B) includes transmission of N-PREs or M-PREs as enhanced sensing signal. This allocation is based on the required increase in SNR to enhance the cross-correlation peak value, thereby improving the sensing accuracy and confidence level. Depending on the data conditions, the higher layer allocates a number of PREs (N-PREs or M-PREs).
[0082] At step (216), N-PREs may be used to encode Radar Signature in the form of SSI (one numeric digit ?? out of 1008) in transmission. The allocation of additional PREs for designing the new enhanced sensing signal is determined by the SNR needed to achieve a high confidence level in sensing. This allocation must include two ZC sequence lengths, as two ZC sequences are necessary for RS-1 and RS-2, which are essential for decoding the SSI of the sensing system (gNodeBs). Alternatively, out of M-PREs, 127 PREs may be utilized for NID2 identification, which may be used to encode radar signature in the form of PCI (one numeric digit ?? out of 1008) in transmission and (M-127) PREs may be used for sensing.
[0083] At step (217), the method (200B) includes capturing and filtering the reflected noisy enhanced signal after reflection from the object (104). At step (218), the method (200B) includes activating Boolean logic for one OFDM Symbol duration or multiple symbol durations depending upon PREs locations to allow new defined sensing signal. At step (219), the method (200B) includes executing the cross-correlation function between the transmitted enhanced sensing signal and filtered reflected signal of periodicity 20 ms and decoding radar signature in the form of SSI from RS-1 and RS-2.
[0084] At step (220), the method (200B) includes determining whether the SSI is same as that of the sensing device (102). If not, the method (200B) will proceed to step (215). If same, at step (222), the method (200B) includes determining whether the peak value of the cross-correlation function is greater than the pre-defined threshold value. If not, the method (200B) proceeds to step (214). If same, the method (200B) proceeds to step (210) of FIG. 2A.
[0085] Referring to FIG. 2A, at step (210), the method (200A) includes determining whether a confidence level of the cross-correlation function is greater than the minimum confidence level (e.g., 50%) for a defined sensing zone of the sensing device (102). At step (211), the method (200A) includes determining the minimum confidence level for detection of the object (104).
[0086] Merely surpassing the threshold value (?) in the cross-correlation peak does not adequately determine the object’s range from the sensing device (102). Instead, there exists a likelihood of the accuracy of this estimated distance, which establishes the confidence level. Additionally, the sensing device (102) characterizes sensing zones into categories such as high confidence, low confidence, and no sensing zones. These zones are defined based on the confidence level, which is quantified as the percentage by which the cross-correlation function's peak value (?’) surpasses the threshold (defined as Excess Value, EV) set by the decision circuit. Mathematically, it can be expressed as:
Excess value (EV) % = ( × 100) %
[0087] Based on this mathematical formula, the sensing device (102) defines its sensing zone as given in the table below.
Excess Value (EV) % Confidence Level (CL) % Sensing Zone
EV < 70 0 No sensing zone
70 = EV < 75 0 < CL = 25 Low confidence sensing zone nearer to No sensing zone
75 = EV < 80 25< CL = 50 Low confidence sensing zone nearer to high confidence sensing zone
EV > 80 50< CL = 100 High confidence sensing zone

[0088] At step (213), if the calculated confidence level (CL) is less than or equal to 50%, further sensing processing should stop, and the sensing technique needs improvement. Additionally, it can be categorized into two conditions;
1) If the confidence level is greater than 0 but less than or equal to 25%, in this case, sensing can be improved by allocating additional PREs from the PDSCH. The only difference is that, instead of PREs being allocated in SSB, they are allocated in PDSCH (within same OFDM slot) to enhance sensing range and resolution, thereby increasing the confidence level.
2) If the confidence level is greater than 25% but less than or equal to 50%, in this case, sensing can be improved by increasing the allocation of PREs in more OFDM Symbols.
[0089] At step (213), if the calculated confidence level (CL) is greater than 50%, in this scenario, the object range may be determined with a high confidence level.
[0090] At step (212), the method (200A) includes calculating the round trip delay (t) from the cross-correlation function and estimating range (R) of object from round trip delay. The round-trip delay (t) in second of the sensing signal can be determined by the decision block (128) by computing the difference between the timestamp at the transmission and the timestamp at the reception of the sensing signal, provided the confidence level falls within the high confidence sensing zone. The reception timestamp can be determined by identifying the time instant at which the cross-correlation function value reaches its highest peak, i.e., the point at which the cross-correlation is highest indicates the correct timing position (reception timestamp) of the received sensing signal.
[0091] Sensing signal travels at the speed of light (c), which is c = 3× meters per second. Range (R) in meter of stationary target can be written as;
R = in meter
[0092] For example, if the round-trip time (t) and range (R) can be calculated as:
t = number of delay samples × sampling time
t = (500) × (8.138 × second)
t = (4.069 × ) second
So the range (R) of the stationary target;
R = = 610.35 meter
[0093] FIG. 10 illustrates an example representation (1000) depicting detection of the object with classification of a confidence zone, in accordance with an embodiment of the present disclosure. In an embodiment, the second buffer (128) is configured to decide if the confidence level is above to minimum confidence level (50%) for the pre-defined sensing zone of sensing device. In an embodiment, the confidence level is established by the accuracy of the estimated distance of the object from the sensing device (102). In an embodiment, there may be multiple objects present in the sensing zone. In another embodiment, the sensing device (102) characterizes sensing zones into categories such as high confidence sensing zone, low confidence sensing zone, and no sensing zones. The sensing zones are defined based on the confidence level.
[0094] FIG. 11 illustrates a schematic representation (1100) of windowing analogue to digital converter (ADC) output with a cyclic prefix (CP) for calulating a round trip delay, in accordance with an embodiment of the present disclosure. In one embodiment, the round-trip delay (t) of the sensing signal can be determined by the second buffer (128) by computing the difference between the timestamp at the transmission sensing signal and the timestamp at the reception of the sensing signal.
[0095] FIG. 12 illustrates a block diagram (1200) representing a system for integrated sensing and communication, in accordance with an embodiment of the present disclosure. The sensing device (1200) for integrated sensing and communication, includes a processor (1212) and a memory (1216).
[0096] The sensing device (1200) may include a bus (1208). The memory (1216) may include a main memory (1202), a read-only memory (1204), a mass storage memory (1206), and a communication port(s) (1210). In an embodiment, the sensing device (1200) may include more than one processor and communication ports. The communication port(s) (1210) may be any of an RS-232 port for use with a modem-based dialup connection, a 10/100 Ethernet port, a Gigabit or 10 Gigabit port using copper or fibre, a serial port, a parallel port, or other existing or future ports. The communication port(s) (1210) may be chosen depending on a network, such a Local Area Network (LAN), Wide Area Network (WAN), or any network to which the computer system (1200) connects. The main memory (1202) may be a random-access memory (RAM), or any other dynamic storage device commonly known in the art. The read-only memory (1204) may be any static storage device(s) including, but not limited to, Programmable Read Only Memory (PROM) chips for storing static information e.g., start-up or basic input/output system (BIOS) instructions for the processor (1212). The mass storage memory (1206) may be any current or future mass storage solution, which may be used to store information and/or instructions.
[0097] The bus (1208) communicatively coupled to the processor (1212) with the other memory, storage, and communication blocks. The bus (1208) can be, a Peripheral Component Interconnect (PCI)/PCI Extended (PCI-X) bus, a Small Computer System Interface (SCSI), a universal serial bus (USB), or the like, for connecting expansion cards, drives, and other subsystems as well as other buses, such a front side bus (FSB), which connects the processor (1212) to the sensing device (1200).
[0098] Optionally, operator and administrative interfaces, e.g. a display, keyboard, and a cursor control device, may also be coupled to the bus (1208) to support direct operator interaction with the sensing device (1200). Other operator and administrative interfaces may be provided through network connections connected through the communication port(s) (1210). In no way should the aforementioned exemplary sensing device (1200) limit the scope of the present disclosure.
[0099] The memory (1216) is operatively coupled with the processor (1212). The memory (1216) stores instructions which, when executed by the processor (1212), cause the sensing device to transmit a sensing signal toward an object. A transmitted sensing signal is stored in a buffer associated with the sensing device.
[00100] The sensing device (1200) is configured to receive a reflected signal, corresponding to the transmitted sensing signal, from the object.
[00101] The sensing device (1200) is also configured to filter the reflected signal to obtain a filtered reflected signal.
[00102] Further, the sensing device (1200) determine an identifier corresponding to the filtered reflected signal by executing a cross-correlation function between the transmitted sensing signal, obtained from the first buffer, and the filtered reflected signal.
[00103] Furthermore, the sensing device (1200) is configured to determine whether the identifier corresponding to the filtered reflected signal is same as that of the sensing device.
[00104] In response to a determination that the identifier is the same, the sensing device (1200) is configured to determine a round trip delay of the sensing signal based on the cross-correlation function, and a difference between a timestamp at the transmission of the sensing signal and a timestamp at the reception of the reflected signal.
[00105] In response to a determination that the identifier is not the same, the sensing device (1200) is configured to continue to receive reflected signals from the object.
[00106] While considerable emphasis has been placed herein on the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter to be implemented merely as illustrative of the invention and not as limitation.

ADVANTAGES OF THE PRESENT DISCLOSURE
[00107] The present disclosure enables integrated sensing and communication efficiently.
[00108] The present disclosure enhances a range and a resolution for high confidence level in a form of high probability of correctness, and reduces a probability of false alarm while maintaining system power levels intact.
[00109] The present disclosure addresses a power leakage between a transmission antenna and a reception antenna in a collocated sensing device.
[00110] The present disclosure ensures an improved performance in a sensing device, and resource optimization.
, Claims:1. A method (200A, 200B) for sensing an object in an integrated sensing and communication (ISAC) system, comprising:
transmitting (201), by a sensing device, a sensing signal, wherein the transmitted sensing signal is stored in a first buffer associated with the sensing device;
receiving (202), by the sensing device, a reflected signal, corresponding to the transmitted sensing signal, from an object;
filtering (203), by the sensing device, the reflected signal to obtain a filtered reflected signal;
determining (206), by the sensing device, an identifier corresponding to the filtered reflected signal by executing a cross-correlation function between the transmitted sensing signal, obtained from the first buffer, and the filtered reflected signal;
determining (207), by the sensing device, that the identifier corresponding to the filtered reflected signal is same as that of the sensing device; and
in response to the determination, determining (212), by the sensing device, a round trip delay of the sensing signal based at least on the cross-correlation function, and a difference between a timestamp at the transmission of the sensing signal and a timestamp at the reception of the reflected signal.
2. The method (200A, 200B) as claimed in claim 1, wherein the sensing signal comprises a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS), and wherein the sensing device is a collocated, monostatic, and active sensing device.
3. The method (200A, 200B) as claimed in claim 1, further comprising:
configuring, by the sensing device, a Boolean logic to true, for two alternate Orthogonal Frequency Division Multiplexing (OFDM) symbol duration, in response to the transmission of the sensing signal; and
configuring, by the sensing device, the Boolean logic to false to block transmission of other signals by the sensing device.
4. The method (200A, 200B) as claimed in claim 2, wherein the identifier corresponds to a Physical Cell Identifier (PCI) of the sensing device, and wherein the PCI is calculated based on the PSS and the SSS.
5. The method (200A, 200B) as claimed in claim 1, further comprising:
comparing, by the sensing device, a peak value of the cross-correlation function with a pre-defined threshold value stored in a second buffer associated with the sensing device;
in response to a determination that the peak value is less than the pre-defined threshold value, redistributing, by the sensing device, power across Physical Resource Elements (PREs) in one of a plurality of configurations; and
in response to a determination that the peak value is greater than the pre-defined threshold value, determining, by the sensing device, a confidence level of the cross-correlation function, wherein the confidence level is based on a degree to which the peak value surpasses the pre-defined threshold value.
6. The method (200A, 200B) as claimed in claim 5, wherein the redistributing comprises:
sending, by the sensing device, a first request to a higher layer to allocate additional PREs in one of: a single Orthogonal Frequency Division Multiplexing (OFDM) symbol, multiple OFDM symbols within same OFDM slot, or a single Primary Synchronization Signal (PSS) OFDM symbol;
in response to the request, receiving, by the sensing device, a notification on the allocated additional PREs from the higher layer;
transmitting, by the sensing device, an enhanced sensing signal in the additional PREs in one of the plurality of configurations;
receiving, by the sensing device, an enhanced reflected signal, corresponding to the transmitted enhanced sensing signal, from the object;
determining, by the sensing device, a sensing sequence identifier (SSI) corresponding to the enhanced reflected signal by executing the cross-correlation function between the transmitted enhanced sensing signal and the enhanced reflected signal; and
determining, by the sensing device, whether the SSI is same as that of the sensing device.
7. The method (200A, 200B) as claimed in claim 6, further comprising:
in response to a determination that the SSI is the same, determining, by the sensing device, whether an enhanced peak value of the cross-correlation function is greater than the pre-defined threshold value; and
in response to a determination that the SSI is not the same, continuing, by the sensing device, the transmission of the enhanced sensing signal.
8. The method (200A, 200B) as claimed in claim 7, further comprising:
in response to a determination that the enhanced peak value is less than the pre-defined threshold value, sending, by the sensing device, a second request to the higher layer to allocate additional PREs with additional OFDM symbols within an OFDM slot; and
in response to a determination that the enhanced peak value is greater than the pre-defined threshold value, determining, by the sensing device, the confidence level of the cross-correlation function.
9. The method (200A, 200B) as claimed in claim 8, wherein in response to determining, by the sensing device, the confidence level, the method comprises:
determining, by the sensing device, whether the confidence level is greater than a minimum confidence level corresponding to a sensing zone of the sensing device;
in response to a determination that the confidence level is less than the minimum confidence level, allocating, by the sensing device, the additional PREs in Physical Downlink Shared Channel (PDSCH) or increasing, by the sensing device, the allocation of the additional PREs in the additional OFDM symbols; and
in response to a determination that the confidence level is greater than the minimum confidence level, determining, by the sensing device, the round-trip delay of the sensing signal and a range of the object from the round-trip delay.
10. The method (200A, 200B) as claimed in claim 6, wherein the enhanced sensing signal comprises a first ranging sequence and a second ranging sequence, each having a variable length, and wherein the SSI is calculated based on the first ranging sequence and the second ranging sequence.
11. The method (200A, 200B) as claimed in claim 6, wherein the plurality of configurations comprises:
allocation of the additional PREs in a single OFDM symbol, wherein the enhanced sensing signal is a 126-length frequency-domain sequence, and wherein each of a first ranging sequence and a second ranging sequence of the enhanced sensing signal has 63-length;
allocation of the additional PREs in two OFDM symbols, wherein the enhanced sensing signal is a 126-length frequency-domain sequence, and wherein each of a first ranging sequence and a second ranging sequence of the enhanced sensing signal has 63-length;
allocation of the additional PREs in four OFDM symbols, wherein the enhanced sensing signal is a 126-length frequency-domain sequence, and wherein each of a first ranging sequence and a second ranging sequence of the enhanced sensing signal has segments of 63-length, each segment having sequences of 31 and 32-length;
allocation of the additional PREs in a single OFDM symbol, wherein the enhanced sensing signal is a 62-length frequency-domain sequence;
allocation of the additional PREs in two OFDM symbols, wherein the enhanced sensing signal is a 62-length frequency-domain sequence, and wherein each of a first ranging sequence and a second ranging sequence of the enhanced sensing signal has 31-length; and
allocation of the additional PREs in four OFDM symbols, wherein the enhanced sensing signal is a 62-length frequency-domain sequence, and wherein each of a first ranging sequence and a second ranging sequence of the enhanced sensing signal has segments of 31-length, each segment having sequences of 15 and 16-length.
12. The method (200A, 200B) as claimed in claim 6, wherein the method (200A, 200B) further comprises:
determining, by the sensing device, a colliding probability factor corresponding to a probability of collision of signals from another sensing device, wherein the colliding probability factor is a ratio of a length of the sensing signal to a length of the enhanced sensing signal, and wherein transmitting, by the sensing device, the enhanced sensing signal in said one of the plurality of configurations is based on the colliding probability factor.
13. The method (200A, 200B) as claimed in claim 1, wherein the method (200A, 200B) further comprises eliminating, by the sensing device, a signal coupling between the transmitted sensing signal and the received reflected signal.
14. A sensing device (1200) for sensing an object in an integrated sensing and communication (ISAC) system, comprising:
a processor (1212); and
a memory (1216) operatively coupled with the processor (1212), wherein the memory (1216) stores instructions which, when executed by the processor (1212), cause the device to:
transmit a sensing signal toward an object, wherein a transmitted sensing signal is stored in a first buffer associated with the sensing device;
receive a reflected signal, corresponding to the transmitted sensing signal, from the object;
filter the reflected signal to obtain a filtered reflected signal;
determine an identifier corresponding to the filtered reflected signal by executing a cross-correlation function between the transmitted sensing signal, obtained from the first buffer, and the filtered reflected signal;
determine whether the identifier corresponding to the filtered reflected signal is same as that of the sensing device;
in response to a determination that the identifier is the same, determine a round trip delay of the sensing signal based on the cross-correlation function, and a difference between a timestamp at the transmission of the sensing signal and a timestamp at the reception of the reflected signal; and
in response to a determination that the identifier is not the same, continue to receive reflected signals from the object.