Abstract: A method for transmitting a signal, and an apparatus, a storage medium, and a user terminal are provided. The method includes: determining a plurality of baseband signals of Component Carriers (CC); selecting a plurality of phase rotation factors and recording a number of times of selection by adding one each time of selection; determining a candidate signal and a Peak to Average Power Ratio (PAPR) of the candidate signal, wherein in response to the PAPR being greater than or equal to a preset threshold and the number of times of selections not reaching a preset number of times, reselecting phase rotation factors and re-determining another candidate signal and a PAPR of the another candidate signal, until a PAPR is less than the preset threshold or the number of times of selections reaches the preset number of times; and transmitting the candidate signal.

Abstract: A distributed acoustic sensing (DAS) system that collects many frequency bands within the system (in particular, analog to digital converter, or ADC) bandwidth. The bands are divided into multiple groups, and within each group, the inter-band interference from band i to band j is at least l1 dB lower than the power of band j. For different groups, the inter-band interference is at least l2 dB lower than the power of band j, that l2?l1+Cl, where Cl is a value related to round-trip fiber loss. The bands belonging to the same group are cascaded one after another, with little guard time in between, or packed back-to-back. This arrangement advantageously increases the overall signal power, resulting in an improved SNR.

Abstract: A spatial averaging method for a coherent distributed acoustic sensing (DAS) system that employs differential beating and polarization combining of signals for two locations along a length of optical sensing fiber to determine phase change in-between every location along the length of the optical sensing fiber and a moving average using polarization combining output to reduce any Rayleigh fading before phase determination.

Abstract: Aspects of the present disclosure describe DFOS/DAS systems, methods, and structures that employ active microphones to enhance DAS operational capabilities by using an active circuit to amplify acoustic signals including voice(s). The circuit includes a microphone to collect acoustic signal(s) resulting from voice signals in the environment, and a speaker or a vibration device driven by an amplifier. The circuit can be clipped onto the fiber, with direct contact through the speaker or vibration device. A microcontroller may advantageously be employed to control the circuit for reduced power consumption, by detecting activities locally and only enabling the speaker when needed. The microcontroller may also send other information such as battery status to the DFOS interrogator through vibration codes.

Abstract: Distributed fiber optic sensing systems (DFOS) methods, and structures that employ DVS / DAS point sensors and a two-stage processing methodology / structure that advantageously enable point sensors to send sensor data at any time - thereby providing significant processing advantages over the prior art.

Abstract: A distributed optical fiber sensing (DOFS)/distributed acoustic sensing (DAS) method employing polarization diversity combining and spatial diversity combining for a DOFS/DAS system wherein the polarization diversity combining determines a temporal average product for each beating product, determines one having a max average power, rotates that one having max average power for its phase shift to produce a reference, determines a phase difference for each beating product as compared to the reference, compensates any phase difference such that all beating products exhibit a well-aligned phase; and combining the beating products; and wherein the spatial diversity combining uses the combined beating products for each location, determines a temporal average power, determines a location having a greatest average power; and combines the results and provides an indicia of the combined result(s).

Abstract: Aspects of the present disclosure describe systems methods and structures for avoiding saturation caused phase jump in systems that extract information from the phase of a complex sequence and exhibit an overflow or “spike” in the output of a high-pass filter. Operationally, during phase unwrapping—when an output signal exceeds a supported range—it is adjusted to be back in range by adding N·2?, to a phase where N is negative or positive integer, depending on the direction to be adjusted.

Abstract: Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously overcome problems encountered when operating DFOS systems over operational telecommunications facilities namely, cross-phase modulation, and uneven amplitude profiles through the use of a novel constant amplitude coded DFOS employing suppressed out-of-band signaling.

Abstract: Disclosed are distributed fiber optic sensing arrangements that—in sharp contrast to the prior art—utilize C-OTDR capabilities to detect an optical fiber end point while still maintaining operational DFOS vibration/acoustic signal sensing functions. Advantageously, such operations are performed automatically without requiring a manual confirmation. A change is made in digital signal processing in the C-OTDR operation by bypassing a high-pass-filtering stage when calculating intensity changes such that the DC signal component is preserved and used to differentiate from a “no-fiber” section. It then calculates the no-fiber section's signal level and uses a back-tracking operation to determine the fiber end automatically.

Abstract: Aspects of the present disclosure describe Rayleigh fading mitigation via short pulse coherent distributed acoustic sensing with multi-location beating-term combination. In illustrative configurations, systems, methods, and structures according to the present disclosure employ a two stage modulation arrangement providing short interrogator pulses resulting in a greater number of sensing data points and reduced effective sectional length. The increased number of data points are used to mitigate Rayleigh fading via a spatial combining process, multi-location-beating combining (MLBC) which uses weighted complex-valued DAS beating results from neighboring locations and aligns phase signals of each of the locations, before combining them to produce a final DAS phase measurement. Since Rayleigh scattering is a random statistic, the MLBC process allows capture of different statics from neighboring locations with correlated vibration/acoustic signal.

Abstract: Aspects of the present disclosure describe distributed optical fiber sensing systems, methods, and structures that advantageously employ point sensors that send sensory data/information over an attached, distributed optical fiber sensor without using a separate network or communications facility.

Abstract: Aspects of the present disclosure describe distributed fiber optic sensing (DFOS) systems, methods, and structures that advantageously overcome problems encountered when operating DFOS systems over operational telecommunications facilities namely, cross-phase modulation, and uneven amplitude profiles through the use of a novel constant amplitude coded DFOS employing suppressed out-of-band signaling.

Abstract: Aspects of the present disclosure describe DFOS/DAS systems, methods, and structures that employ active microphones to enhance DAS operational capabilities by using an active circuit to amplify acoustic signals including voice(s). The circuit includes a microphone to collect acoustic signal(s) resulting from voice signals in the environment, and a speaker or a vibration device driven by an amplifier. The circuit can be clipped onto the fiber, with direct contact through the speaker or vibration device. A microcontroller may advantageously be employed to control the circuit for reduced power consumption, by detecting activities locally and only enabling the speaker when needed. The microcontroller may also send other information such as battery status to the DFOS interrogator through vibration codes.

Abstract: Physimetric-based data security for coded distributed temperature sensing (DTS) in which physimetric information is extracted from a coded-DTS interrogator which is unique for each interrogator at each operating run time—and used to reconstruct a final temperature determination from DTS data. The physimetric information includes coded-DTS pulse code and coded-DTS pulse profile information as a key to permit secure sharing with authorized users. The pulse code and pulse profile information are encrypted and made available to an authorized user. The authorized user can then decrypt the pulse code and pulse profile information and subsequently use this key information (pulse profile and pulse code files) to retrieve temperature information from for example, a remote computer providing a continuous raw data feed—without being susceptible to eavesdropping.

Abstract: An optical fiber sensing system with reduced spatial resolution and noise for multiple applications and method of operating same that employs a coherent receiver configured to detect and digitize both I and Q signals in two polarizations and performs signal beating in a digital signal processor (DSP) using the polarization-diverse signals to obtain beating results for multiple polarization state pairs that effectively reduces polarization induced fading effect(s) while providing faster sensing speed(s) and more efficient filtering. Since Rayleigh signals are captured in two orthogonal polarizations, four beating products are determined at once in the DSP and all are used for fiber strain determination thereby avoiding polarization fading.

Abstract: Aspects of the present disclosure describe a computer implemented method for the transfer of sensor data on dynamic software defined network (SDN) controlled optical network.

Abstract: Aspects of the present disclosure describe systems, methods and structures for coherent distributed sensing that employs a moving average method among locations along a sensing fiber employing a user configured number of taps that involves location grouping and a group's internal phase alignment followed by an inter-group phase alignment and combining. Our method employs two steps of rotation to achieve the alignment: intra-group rotation and inter-group rotation to align the phase of all participating sensing fiber locations.

Abstract: Aspects of the present disclosure are directed to improved systems, methods, and structures providing coherent detection of DAS. In sharp contrast to the prior art, systems, methods, and structures according to aspects of the present disclosure advantageously reduce the beating diversity terms such that required memory and bandwidth are reduced over the art.

Abstract: Aspects of the present disclosure describe systems methods and structures for avoiding saturation caused phase jump in systems that extract information from the phase of a complex sequence and exhibit an overflow or “spike” in the output of a high-pass filter. Operationally, during phase unwrapping—when an output signal exceeds a supported range—it is adjusted to be back in range by adding N·2?, to a phase where N is negative or positive integer, depending on the direction to be adjusted.

Abstract: Aspects of the present disclosure describe a polarization diversity combining method for coherent distributed acoustic sensing (DAS) maintaining phase continunity.