6 results about "Chirp spread spectrum" patented technology

The application discloses a communication method, device, communication equipment and readable storage medium, and belongs to the technical field of communication. The communication method of the application embodiment comprises the following steps: a first device performs a first operation; wherein the first operation comprises at least one of the following: respectively sending a plurality of reader-to-device (R2D) signals to a plurality of second devices, and respectively receiving a plurality of device-to-reader (D2R) signals sent by the plurality of second devices; the R2D signal is a chirp spread spectrum (CSS) modulation signal; the D2R signal is a CSS modulation signal; each two R2D signals in the plurality of R2D signals have orthogonality or quasi-orthogonality, and each two D2R signals in the plurality of D2R signals have orthogonality or quasi-orthogonality.

A system and a method thereof for performing modulation and demodulation based on a chirp spread band technique are disclosed. A system for performing modulation and demodulation based on a chirp spread band technique according to one embodiment of the present disclosure includes: a transmitter that transmits a chirp signal; and a receiver that receives and demodulates the chirp signal. The transmitter determines the number of data bits (M) modulated in a unit symbol based on a first residual carrier frequency offset and a spreading factor (SF), and transmits a first chirp signal obtained by modulating the first data bits in at least one symbol according to the determined number of data bits modulated in the unit symbol to the receiver. The receiver may transmit information indicating a second residual carrier frequency offset detected based on the received first chirp signal to the transmitter.

The application relates to a method and device for tracking an ultra-wideband navigation signal based on a linear frequency modulation spread code, and belongs to the technical field of satellite navigation. The method comprises the following steps: receiving an ultra-wideband navigation signal and multiplying the signal with a local in-phase carrier and a local quadrature carrier respectively to obtain in-phase components and quadrature components; obtaining a local linear frequency modulation spread code which is output after being bound by phase calculation, phase quantization, code generation and signal transmission time delay; obtaining a local pseudo-random spread code which is output after being bound by signal transmission time delay; combining the two types of spread codes to generate three types of spread codes, namely delayed, instant and advanced spread codes, and performing coherent integration on the in-phase components and the quadrature components which are divided into three paths; calculating the phase error and the time delay error of the current received signal and the local carrier according to the coherent integration result; and finally, repeatedly generating the carrier and the two types of spread codes based on error feedback to cyclically realize the tracking of the ultra-wideband navigation signal. The method can reduce the complexity of tracking the ultra-wideband navigation signal.

This application relates to a covert communication method, computer device, and readable storage medium utilizing linear spread spectrum modulation of nonlinear chirped spread spectrum amplitude. The method includes nonlinear spread spectrum LoRa communication between a transmitter and a receiver via a legitimate channel. The covert communication method comprises: at the transmitter, performing covert chirped modulation of the legitimate channel amplitude based on a linear chirped spread spectrum modulation method to form a covert channel carrying covert information; embedding the covert channel into the legitimate channel to obtain a transmission signal containing both legitimate and covert information; at the receiver, receiving the transmission signal through a legitimate receiver and demodulating it using legitimate nonlinear chirped modulation to obtain legitimate information; and at the receiver, receiving the transmission signal through a covert receiver, processing it with covert chirped information, and then performing covert chirped demodulation based on a linear chirped spread spectrum modulation method to obtain the covert information. This application embeds covert information into a legitimate nonlinear spread spectrum LoRa channel, improving the parallel transmission capacity of covert information.

The application relates to a method and device for generating an ultra-wideband navigation signal based on a linear frequency modulation spread code, and belongs to the technical field of satellite navigation. The method comprises the following steps: generating a linear frequency modulation spread code of a data / pilot branch by using a phase quantization model which satisfies a cooperative optimization constraint of generation complexity and sidelobe suppression performance; generating a pseudo-random spread code of the data / pilot branch; generating a data code containing navigation messages; generating a digital baseband signal of a pilot branch according to the pseudo-random spread code and the linear frequency modulation spread code of the pilot branch, and performing digital-to-analog conversion; generating a digital baseband signal of a data branch according to the data code, the pseudo-random spread code and the linear frequency modulation spread code of the data branch, and performing digital-to-analog conversion; and generating a complete ultra-wideband navigation signal according to the analog baseband signals of the data / pilot and a radio frequency carrier. The method can greatly reduce the complexity of generating an ultra-wideband navigation signal, and provides key technical support for the application of the ultra-wideband navigation signal.