By changing frequencies of an oscillation signal and an injection signal, a frequency-converted self-injection-locked radar has an oscillation frequency different to a frequency of a transmitted signal from a transceiver antenna element such that the frequency-converted self-injection-locked radar with high sensitivity and penetration or with high sensitivity d low cost is achieved.

A system and method for narrowband sinewave modulation. The system includes an input buffer for storing input digital data and a sub-periodic modulator for encoding the input digital data in a periodic waveform. The sub-periodic modulator encodes one or more bit values of the input digital data within each period of the periodic waveform. One or more digital-to-analog converters generate an encoded analog waveform from a digital representation of the periodic waveform wherein the encoded analog waveform is of a frequency f and a power P. The encoding is performed by the sub-periodic modulator such that any signal of frequency f resulting from the encoding is of a power P at least 50 dB less than power P, where f is offset from f by more than 25 Hz.

Provided is a transmission method that improves data reception quality in radio transmission using a single-carrier scheme and/or a multi-carrier scheme. The transmission method includes: generating a plurality of first modulated signals s1(i) and second modulated signals s2(i) from transmission data, the plurality of first modulated signals s1(i) being signals generated using a QPSK modulation scheme, and the plurality of second modulated signals s2(i) being signals generated using 16QAM modulation; generating, from the plurality of first modulated signals s1(i) and the plurality of second modulated signals s2(i), a plurality of first signal-processed signals z1(i) and a plurality of second signal-processed signals z2(i) which satisfy a predetermined equation; and transmitting the plurality of first signal-processed signals z1(i) and the plurality of second signal-processed signals z2(i) using a plurality of antennas. A first signal-processed signal and a second signal-processed signal having identical symbol numbers are simultaneously transmitted at the same frequency.

Wideband polar receivers and method of operation are described. A phase-modulated input signal is received at a polar receiver that includes an injection-locked oscillator. The injection-locked oscillator includes a plurality of injection points. Based on the frequency of the input signal, a particular Nth harmonic is selected, and the input signal is injected at the set of injection points corresponding to the selected Nth harmonic. The injection-locked oscillator generates an oscillator output signal, and the phase of the input signal is determined from the phase of the oscillator output signal. In some embodiments, the oscillator output signal is frequency-multiplied by N, mixed with the input signal, and filtered for use in amplitude detection. The input signal is decoded based on the phase and amplitude information.

A system and method of estimating metric values from digital samples of received communications signal carrying symbols modulated in a selected first modulation format and symbols modulated in a second modulation format. The selected first modulation format can be selected from among multiple supported first modulation formats. The system can receive the digital samples in sample blocks a plurality of which constitute a data frame. Each sample block can comprise a first region that contains first samples corresponding to the selected first modulation format or overhead samples regardless of the selected first modulator format or an index of the sample block in the frame; a second region that contains second samples corresponding to a second modulation format regardless of the selected first modulator format or an index of the sample block in the frame; and a third region in which whether the samples are first samples or second samples depends on the selected first modulation format or the index of the sample block in the frame. The system estimates first metrics according to the selected first modulation format for each of the first samples and second metrics according to the second modulation format for each of the second samples. The system also estimates both first metrics and second metrics for each of the third samples and then selects valid ones of the first metrics and second metrics for the third samples in accordance with the selected first modulation format or the index of the sample block in the frame.

A reception device includes: a receiver that receives a multiplexed signal; a first demapper that demaps the multiplexed signal, with a second modulated symbol stream of a second data series being included in the multiplexed signal as an undefined signal component, to generate a first bit likelihood stream of a first data series; a second demapper that demaps the multiplexed signal, with a first modulated symbol stream of the first data series being included in the multiplexed signal as an undefined signal component, to generate a second bit likelihood stream of the second data series; a first decoder that performs error control decoding on the first bit likelihood stream to derive the first data series; and a second decoder that performs error control decoding on the second bit likelihood stream to derive the second data series.

A data communications system and method having high spectral efficiency. The method includes encoding input digital data using a plurality of symbol waveforms. Each symbol waveform occupies a period of a composite encoded waveform and represents one or more bits of the input digital data. Each symbol waveform has a first elliptical segment and a second elliptical segment of opposite polarity. The encoding includes defining each symbol waveform so that (i) a zero crossing from the first elliptical segment to the second elliptical segment of the symbol waveform is different for each of the symbol waveforms, and (ii) an energy of the first elliptical segment of the symbol waveform is substantially equal to an energy of the second elliptical segment of the symbol waveform. An encoded analog waveform is generated, using a digital-to-analog converter, from a digital representation of the composite encoded waveform.

Coded antenna arrays and associated methods, apparatus and systems are disclosed. Signals transmitted by a client device are received at a plurality of antennas or antenna elements in an antenna array. The received signals are coded using codes such as orthogonal codes and pseudorandom number sequences under which the codes are selected to enable extraction of individual received signals. The coded signals are then combined to form a combined coded waveform that is processed using shared receiver circuitry. The shared receiver circuitry is configured to extract the signals received at each antenna using the codes used to code the received signals. Use of multiple client devices is also supported, with the receiver circuitry further configured to filter out signals received from individual client systems and calculate the phase and magnitude of the signals as received at each antenna. The signal phase and magnitude may be used for wireless transmission of power to clients by a wireless power transmission system.

Provided is a transmission method that improves data reception quality in radio transmission using a single-carrier scheme and/or a multi-carrier scheme. The transmission method includes: generating a plurality of first modulated signals s1(i) and second modulated signals s2(i) from transmission data, the plurality of first modulated signals s1(i) being signals generated using a QPSK modulation scheme, and the plurality of second modulated signals s2(i) being signals generated using 16QAM modulation; generating, from the plurality of first modulated signals s1(i) and the plurality of second modulated signals s2(i), a plurality of first signal-processed signals z1(i) and a plurality of second signal-processed signals z2(i) which satisfy a predetermined equation; and transmitting the plurality of first signal-processed signals z1(i) and the plurality of second signal-processed signals z2(i) using a plurality of antennas. A first signal-processed signal and a second signal-processed signal having identical symbol numbers are simultaneously transmitted at the same frequency.

A system and method for waveform modulation includes encoding input digital data at selected phase angles of an unmodulated sinusoidal waveform. The encoding includes selectively reducing a power of the unmodulated sinusoidal waveform at the selected phase angles in accordance with bit values of the input digital data so as to respectively define first, second, third and fourth data notches in the modulated sinusoidal waveform. An encoded analog waveform is then generated from a digital representation of the modulated sinusoidal waveform. The encoding is performed so that energies associated with the first and third data notches are balanced and energies associated with second and fourth data notches are also balanced. Each of the energies corresponds to a cumulative power difference between a power of the unmodulated sinusoidal waveform and a power of the modulated sinusoidal waveform over a phase angle range subtended by one of the data notches.