An apparatus and a method. The apparatus includes a channel estimation (CE) module, including a first input for receiving pilot resource element (RE) observations, a second input for receiving data RE observations, a third input for receiving log-likelihood ratios (LLRs), and an output; a detector, including a first input connected to the output of the CE module, a second input for receiving data RE observations, and an output connected to the third input of the CE module; and a decoder, including an input connected to the third input of the CE module, and an output.

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.

A data communication method in which input digital data is received and encoded into an encoded waveform having zero crossings representative of the input digital data. The encoding includes generating the encoded waveform based upon a continuous piecewise function having sinusoidal components. The continuous piecewise function may be used in generating a plurality of symbol waveforms, each of which occupies a period of the encoded waveform and represents bits of the input digital data. The plurality of symbol waveforms are defined so that a value of a phase offset used in the continuous piecewise function is different for each of the plurality of symbol waveforms, thereby resulting in each symbol waveform having a different zero crossing. An encoded analog waveform is generated from a representation of the encoded waveform and transmitted to a receiver.

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 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.

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.

The present invention belongs to the field of IoT (Internet of Things) chips, and discloses a BLE protocol-based battery-free multi-mode transceiver including a wireless energy harvester module, a power management module, a transmitter, a receiver and a backscattering module, where the wireless energy harvester module supplies power to the whole transceiver; the power management module provides required stable currents and voltages for circuits; the transmitter modulates a baseband signal inputted by an external device into a GFSK modulated Bluetooth intermediate frequency signal compatible to a BLE protocol, modulates a received continuous waveform signal by using a backscattering technology, backscatters digital information compatible to the BLE protocol, and transmits a Bluetooth radio frequency signal; the receiver receives the Bluetooth radio frequency signal, amplifies the Bluetooth intermediate frequency signal in an output of the rectifier, and demodulates the Bluetooth intermediate frequency signal to a Bluetooth baseband signal.

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.

Optimal GMSK training sequences are generated by applying a base sequence to the in-phase component of the even samples and rotating the base sequence by 2.sup.k-1 and applying the second sequence to the quadrature component of the odd samples. Using the optimal GMSK training sequence a channel estimate can be generated. Filtering the channel estimate converts the channel impulse response to one that can be used with a non-GMSK signal e.g. PSK or QAM.