Technologies directed to improving power for wireless transceivers are described. One method processes, in a first power mode, a first portion of a data packet, the first portion being modulated with a FSK modulation. The method determines a first gain value for an amplifier and determines that the first data packet has a second portion that is modulated with a PSK modulation. The method determines a receive signal strength indicator (RSSI) value associated with the first portion and determines that the RSSI does not exceed a threshold value corresponding to a throughput requirement. The method switches to a second power mode, the second power mode being higher in power than the first power mode. The method determines, in the second power mode, a second gain value for the amplifier and process the second portion of the first data packet. The second gain value is determined before the processing the second portion.

The invention relates to a method for decoding an RF signal bearing a sequence of transmitted symbols modulated by CPM. The method comprises, at the receiver (1): Estimating model parameters {h, ω, Φ.sub.0} among which h characterizes a modulation index, ω characterizes a carrier frequency offset and Φ.sub.0 characterizes an initial phase offset, and Detecting received symbols corresponding to said transmitted symbols of the sequence, wherein, at time nT where T is a symbol duration, the parameters {h, ω, Φ.sub.0} are estimated by solving a system of three linear equations whose: a. three unknowns {ĥ.sup.(n), {circumflex over (ω)}.sup.(n), {circumflex over (Φ)}.sub.0.sup.(n)}, are respectively function of said model parameters {h, ω, Φ.sub.0}, and b. coefficients {B.sup.(n), C.sup.(n), D.sup.(n), F.sup.(n), G.sup.(n), H.sup.(n), v.sub.1.sup.(n), v.sub.2.sup.(n), v.sub.3.sup.(n)} are computed in a recursive way in function of: iii. a sequence of symbols {â.sub.n} corresponding to the sequence of transmitted symbols up to time nT, and iv. measured phases {Ψ.sub.k} of samples {y.sub.k} of the RF signal received from time (n−1)T to time nT.

The present disclosure discloses an M-ary DCSK method based on chaotic shape-forming filtering. The method includes the following steps: at S1, parameters of a communication system are set; at S2, HP information and LP information to be sent in each time slot are prepared; at S3, the information to be sent is modulated; at S4, a chaotic carrier is generated through a chaotic shape-forming filter; at S5, a transmitted signal is prepared; at S6, down-carrier frequency and matched filter is performed to a received signal; at S7, the sampling of a maximum SNR point is performed to an output signal of a matched filter; at S8, the decision of high priority information bits is resumed; and at S9, the decision of low priority information bits is resumed.

Technologies directed to improving signal quality in received wireless signals in the phase domain of shift keying demodulation are described. One method receives digital data, the digital data including a systematic error as a linear function of residual carrier frequency offset and phase noise (PN). The method extracts first phase data from the digital data, determines, in a phase domain, an estimate of the systematic error using historical phase error data of additional digital data received prior to the digital data, and generate second phase data by subtracting the estimate from the first phase data. The method determines a set of symbols from the second phase data and generates a bit sequence of a data packet from the set of symbols.

Technologies directed to improving power for wireless transceivers are described. One method receives, in a low power mode, a data packet over a wireless link and determines a RSSI value and a receive signal quality indicator (RSQI) value. The method stores a record with the RSSI and RSQI values in memory. The method determines an average RSSI value and an average RSQI value from historical RSSI and RSQI values, respectively, stored in records. The method categorizes received data in a first channel quality indicator (CQI) category using the average RSSI value and the average RSQI value and configures the wireless device to operate in another power mode, responsive to the data being in the first CQI. The method processes a subsequent data packet while in the other power mode. In some cases, the other power mode is less than a maximum power mode specified by a wireless standard.

An improved coherent communication scheme is provided. The coherent communication scheme encodes both classical and quantum information simultaneously using isolated groups of states: classical information is represented by different groups and can be decoded deterministically; and quantum information is represented by highly overlapped states within the same group, thus guaranteeing security. Decoding includes projecting the detection results at the receiver to one of the distinguishable encoding groups first, which allows the classical information to be read out, and then generating a quantum key from the residual randomness. This communications scheme enables simultaneous classical communication and QKD over the same communication channel using the same transmitter and receiver, opening the door to operate QKD in the background of classical communication and at negligible costs.

The present disclosure discloses an M-ary DCSK method based on chaotic shape-forming filtering. The method includes the following steps: at S1, parameters of a communication system are set; at S2, HP information and LP information to be sent in each time slot are prepared; at S3, the information to be sent is modulated; at S4, a chaotic carrier is generated through a chaotic shape-forming filter; at S5, a transmitted signal is prepared; at S6, down-carrier frequency and matched filter is performed to a received signal; at S7, the sampling of a maximum SNR point is performed to an output signal of a matched filter; at S8, the decision of high priority information bits is resumed; and at S9, the decision of low priority information bits is resumed.

Signal transmission with symbol correction is disclosed. In one example, processing includes selection of one of known data and unknown data for each of symbols, as transmission data, while selecting a symbol of the known data for a reception side at one or both of timings of immediately before and immediately after selection of a symbol of unknown data for the reception side, modulation of each of the symbols of the selected transmission data, and transmission of a transmission signal obtained. Moreover, processing includes: reception of a transmission signal transmitted from a transmission side; and correction of a symbol of unknown data included in the received transmission signal on the basis of a symbol of known data included in the received transmission signal.

A technique of separating a sequence of modulation shift keying (MSK) symbols into a first portion and a second portion and separately comparing the first portion of the sequence of MSK symbols and the second portion of the sequence of MSK symbols against a first portion of a reference sequence of MSK symbols and a second portion of the reference sequence of MSK symbols allows a low complexity detection of a start field delimiter in a wireless communication packet.

A method of recovering information encoded by a modulated sinusoidal waveform having first, second, third and fourth data notches at respective phase angles, where a power of the modulated sinusoidal waveform is reduced relative to a power of an unmodulated sinusoidal waveform within selected ones of the first, second, third and fourth data notches so as to encode input digital data. The method includes receiving the modulated sinusoidal waveform and generating digital values representing the modulated sinusoidal waveform. A digital representation of the unmodulated sinusoidal waveform is subtracted from the digital values in order to generate a received digital data sequence, which includes digital data notch values representative of the amplitude of the modulated sinusoidal waveform within the first, second, third and fourth data notches. The input digital data is then estimated based upon the digital data notch values.