Technologies directed to improving power for wireless transceivers are described. One method determines, in a first mode, a first value associated with a wireless link and a second values associated with the wireless link, the first value being indicative of a first metric and the second value being indicative of a second metric different from the first metric. The first value and the second value collectively indicate a category of channel quality for the wireless link. The method determines that the wireless device can operate in a second mode for subsequent data based on the category of channel quality, wherein in the second mode the wireless device consumes less power than in the first power mode. The method receives, in the second mode, second data over the wireless link.

A system and method for generating a high entropy (HE) constant-envelope Gaussian minimum shift keying (GMSK) modulated signal with suppressed cyclostationary features is disclosed. In embodiments, the system includes a primary GMSK modulator for generating an initial GMSK signal based on a received data stream for transmission. The system includes a sequence of secondary GMSK modulators for generating a sequence secondary GMSK signals based on pseudorandom number sequences based on distinct chip rates. The initial GMSK signal is multiplied by the first secondary GMSK signal to generate an initial composite GMSK signal, which is sequentially multiplied by each subsequent secondary GMSK signal until a final composite GMSK signal is achieved, the final composite GMSK signal being a HE-GMSK constant-envelope signal with suppression of cyclic and cyclostationary features that might otherwise cause detection or interception of the signal.

A communication system for equipment in airborne operations comprising: at least one first double transceiver and at least one second double transceiver, wherein the at least one first double transceiver is configured to send data to the at least one second double transceiver in two redundant main channels and wherein the data to be sent through each redundant main channel is first compared with each other so as to ensure that the data sent through a first main channel is the same data sent through a second main channel.

An analog fractional-N phase-locked loop includes an oscillator loop having a reference input, a feedback input, and a loop output, and a fractional feedback divider configured to divide signals on the loop output by a divisor. Output of the fractional feedback divider is fed back to the feedback input. A compensation circuit is coupled to, and configured to apply a time delay to, the reference input or the feedback input, to compensate for delay introduced by the fractional feedback divider. The compensation circuit may be a digital-to-time converter configured to convert a digital delay signal into the time delay. The digital-to-time converter may be coupled to the reference input to delay signals to match feedback delay introduced by the fractional feedback divider, or to the feedback input to subtract the time delay to cancel feedback delay introduced by the fractional feedback divider.

A transmitting device (20) overlays control information onto information bit stream intended for a receiving device (40) by varying or shifting the modulation index in continuous phase modulation (CPM) waveform. The receiving device (40) detects the modulation index used at the transmitting device (20) to modulate the data burst. The receiving device (40) then determines the control information based on the detected modulation index.

A method for decoding an RF signal bearing a sequence of transmitted symbols modulated by CPM. The method includes, at the receiver: 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: 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 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: a sequence of symbols {â.sub.n} corresponding to the sequence of transmitted symbols up to time nT, and measured phases {Ψ.sub.k} of samples {y.sub.k} of the RF signal received from time (n−1)T to time nT.

A heart generated signal is provided by a heart sensor of a mobile device to an analog to digital (A/D) converter for A/D converting the sensor provided signal. The A/D converted heart signal is processed to provide heart rate. The heart rate is recorded or stored in the mobile device or is transmitted in a wireless communication system. The mobile device receives sensor provided Electro Cardiogram (ECG) signal. The ECG signal is stored or is provided to an interface unit. The mobile device has transceivers for receiving and transmitting Orthogonal Frequency Division Multiplexed (OFDM) signals and for modulating and transmitting spread spectrum baseband signals. The spread spectrum baseband signals have cross-correlated in-phase and quadrature-phase filtered baseband signals.

A radio transmission method which includes a steps of simulation of a phase modulation of a radio carrier by the successive transmission of a carrier of a main frequency f and of a carrier of an offset frequency f+Δf, the offset frequency having a frequency difference suitable for simulating a given phase shift of the main frequency at the end of a given time T. The invention further relates to a radio transmission device for implementing the method which includes a radio integrated circuit for generating programmable frequency modulation, means for programming, in this radio integrated circuit, the main frequency f and the offset frequency f+Δf and means for driving this radio integrated circuit in order to generate the frequencies as a function of the signal to be transmitted.

In an embodiment, a receiver detects a timing error between a transmitter clock at a transmitter and a receiver clock at a receiver associated with an exchange of CPM signals. The receiver phase aligns input samples of a candidate received signal over a time window based on a rotating signal corresponding to a phase progression of the candidate received signal. The receiver generates first and second partial sums of the phase-aligned input samples that are accumulations of phase-aligned input samples corresponding to modulation symbols that contribute positive and negative phases, respectively, to the phase progression. The receiver determines a phase difference between the first and second partial sums, and generates a timing-error metric that is indicative of a timing error between the transmitter clock and the receiver clock based at least in part upon the determined phase difference.

In one aspect, a method for estimating residual carrier frequency offset (CFO) in a phase-modulated wireless signal having pseudo noise (PN) spreading is provided. The method includes receiving, at a digital transceiver, a plurality of PN spread blocks of in-phase and quadrature (I/Q) samples of the phase-modulated wireless signal and performing sample-level de-rotation, symbol-level de-spreading, and sign alignment. The method also includes estimating a phase difference and determining an estimated residual CFO based on the phase difference.