The communication process for high-sensitivity and synchronous demodulation signals between a transmitter (2) and a receiver (3) comprises a first synchronisation phase followed by a modulation and demodulation phase of the data. To achieve this, the transmitter transmits a pseudo-periodic chirp signal to the receiver, where a frequency conversion of the chirp signal is performed in a mixer (33) by an oscillating signal (So) at constant frequency of a local oscillator (34) to supply an intermediate signal, which is filtered and sampled for a logic unit (37). An assembly (38) of m pairs DFT blocks phase-shifted in relation to one another and operating in parallel is provided in the logic unit. A processing unit (39) receives the result of the pairs of the assembly to determine frequency and phase errors between the transmitter and the receiver on the basis of two peaks detected by one of the pairs above a threshold to synchronise the receiver.

A method and apparatus for underwater acoustic communication are disclosed. A data packet frame structure in the communication transmission includes a preamble, a synchronization code, and a data code. A guard interval is disposed between the preamble and the synchronization code. This method utilizes the different impact response environments of linear frequency modulation signals in different frequency bands to obtain the mapping relationships corresponding to the characteristics of the impulse responses in the frequency band, and adopts the quadrature phase shift keying (QPSK) modulation method to convert four groups of LMF signals with different center frequencies and the same modulation frequency, representing different symbols for signal transmission, where the LFM carrier signal of each center frequency can represent two bits of binary information to improve transmission efficiency. The apparatus for underwater acoustic communication also has the above-mentioned technical effects.

Methods, systems, and devices for wireless communications are described. Generally, a user equipment (UE) may identify an angle parameter for encoding uplink messages using a fractional Fourier Transform (FrFFT). A base station may transmit a set of angle parameters or a single angle parameter that the UE is to use for encoding an uplink message. The UE may select an alpha value from the set of alpha values for the encoding. The UE may transmit an indication of a set of proposed angle parameters to the base station, and the base station may determine and indicate one of or a subset of the received set of proposed angle parameters to the UE. The base station may indicate a correspondence between angle parameters and beam configurations, and the UE may identify an alpha parameter value based on a subsequently indicated beam configuration.

Disclosed by the present invention is a sub-band selection activation-based multi-band hyperbolic frequency modulation spread spectrum underwater acoustic communication method. The present invention discloses: dividing the available bandwidth of an underwater acoustic system into a plurality of sub-bands, performing hyperbolic frequency modulation on each of the sub-bands respectively, and performing spread spectrum modulation on the plurality of sub-bands within the same frequency modulation period, thus implementing multi-band parallel transmission. Hence, within each frequency modulation period, the divided plurality of sub-bands is grouped, and each sub-band group activates different sub-bands for transmission according to different options for transmitting data. Compared to other underwater acoustic hyperbolic frequency modulation communication solutions, the present invention further improves the frequency band utilization of the system, and the energy efficiency is also improved.

A method for generating a signal including a temporal succession of modulated chirps. The modulation corresponds to a circular permutation of the variation pattern of the instantaneous frequency of a base chirp over the symbol time Ts, obtained by a time shift of s times an elementary time period Te, such that M*Tc=Ts. Such a method includes, to generate a given chirp in the temporal succession of chirps, differential encoding between a modulation symbol associated with a chirp preceding the given chirp in the temporal succession of chirps, on the one hand, and a given information symbol of the constellation of M symbols, on the other hand, the differential encoding delivering a given modulation symbol; and modulating the base chirp on the basis of the given modulation symbol generating the given chirp.

An apparatus for determining a suitability of a frequency band for data communication with a node by way of a communication channel may be provided. The apparatus may comprise a receiver configured to receive first and second signals from the node by way of the communication channel, the first and second signals having frequencies within the frequency band. The apparatus may comprise processing circuitry communicatively coupled to the receiver, the processing circuitry being configured to determine a calibration function depending on the first signal, process the second signal depending on the calibration function, determine the suitability of the frequency band for data communication with the node by way of the communication channel depending on the processed second signal and output an indication of the said suitability. The processing circuitry may be configured to determine the suitability of the frequency band for data communication with the node depending on the processed second signal by comparison of the processed second signal to predetermined reference data.

The present technology relates to a transmission device and method as well as a reception device and method which can suppress the influence of interference. The transmission device sets different methods of changing the frequency of the chirp modulation for each of first information and second information different from the first information. The transmission device transmits the chirp-modulated first information or second information in accordance with the set frequency change method. The present technology can be applied to a wireless communication system.

A method is provided. In some examples, the method includes generating, by processing circuitry, a spread of chips representing an input bit. In addition, the method includes converting, by the processing circuitry, the spread of chips to a plurality of symbols comprising a pair of symbols. The method also includes mapping, by the processing circuitry, the pair of symbols to a single carrier signal and generating, by the processing circuitry, a radio-frequency (RF) signal based on the single carrier signal. The method further includes transmitting, by the processing circuitry via an antenna, the RF signal.

Methods, systems, and devices for wireless communications are described. Generally, a user equipment (UE) may identify an angle parameter for encoding uplink messages using a fractional Fourier Transform (FrFFT). A base station may transmit a set of angle parameters or a single angle parameter that the UE is to use for encoding an uplink message. The UE may select an alpha value from the set of alpha values for the encoding. The UE may transmit an indication of a set of proposed angle parameters to the base station, and the base station may determine and indicate one of or a subset of the received set of proposed angle parameters to the UE. The base station may indicate a correspondence between angle parameters and beam configurations, and the UE may identify an alpha parameter value based on a subsequently indicated beam configuration.

The embodiment of the invention provides a modulator, which comprises: a channel coding module for carrying out channel coding on data needing to be sent; a m-ary digital phase modulation module which is used for carrying out modulation mapping on the data which is subjected to channel coding and for obtaining corresponding phase data; a differential phase modulation module which is used for modulating the phase data into an initial phase; and a chirp signal generation module which is used for generating a target chirp signal according to the initial phase. By adopting the modulator to generate the target chirp signal, and initial phase can be obtained, the problem of phase ambiguity can be solved, and the chirp signal can be modulated, transmitted, received, and demodulated more accurately.