Embodiments of this disclosure provide a signal transmission apparatus, a carrier phase recovery apparatus and method. By inserting phase modulation signals with variable amplitudes into data modulation signals and performing carrier phase recovery on received signals at a receiving end according to the phase modulation signals, the apparatuses and methods are applicable to communications systems of various modulation formats and are compatible with existing communications systems, and calculation complexity is relatively low. Furthermore, as the amplitudes of the inserted phase modulation signals are variable, the phase modulation signals may be flexibly configured in data modulation signals, to lower redundancy and influence on the system capacity is relatively small.

Embodiments of an access point (AP), station (STA) and method for communication in accordance with frame formats of varying sizes of pilot portions are generally described herein. The AP may transmit, to the STA, a first downlink frame in accordance with a first downlink frame format. The AP may receive, from the STA, a phase noise measurement of the STA. The AP may select, based at least partly on the received phase noise measurement, a downlink frame format to enable a phase noise compensation at the STA. The AP may generate a downlink frame in accordance with the second downlink frame format, and may transmit the second downlink frame to the STA. In some cases, the first and second downlink frame formats may be based on different ratios of pilot portions to data portions.

In described examples, a method of operating a transmitter includes generating a frequency reference signal having a reference frequency and outputting the frequency reference to a phase locked loop (PLL) that includes a voltage controlled oscillator (VCO). The VCO output is locked to the frequency reference signal to form a carrier signal. The transmitter receives an I input signal, a Q input signal, and a direct current (DC) leaky carrier signal. Either the I input signal or the Q input signal is added to the leaky carrier signal. The carrier signal is modulated with the resulting two signals using an I-Q mixer to generate a modulated signal that includes an unmodulated carrier signal component. The modulated signal is then transmitted.

An estimating apparatus for bias drift of a transmitting end modulator, a compensating apparatus, a receiver and a method are disclosed. Estimation and compensation of the bias drift are performed directly at the receiving end according to phase recovered received signals, with no need of providing an extra bias control circuit at the transmitting end. Estimating and compensating for the bias drift includes recovering received signals by removing a frequency difference and a phase difference between a transmitting end laser and a receiving end laser producing phase recovered received signals, estimating the bias drift of the transmitting end modulator according to the phase recovered received signals and compensating the bias drift of the transmitting end modulator in a receiver.

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.

A coherent optical reception device includes a local oscillation laser that supplies laser light, a coherent optical reception front-end unit that receives a multi-level modulated optical signal, demodulates the optical signal on the basis of the laser light, and converts a demodulated optical signal into an electrical analog signal, an analog-to-digital converter that converts the analog signal into a digital signal, a compensation unit that compensates for an influence of dispersion due to a wavelength or a polarized wave of the optical signal and recovers a carrier phase of the digital signal, a constellation distortion compensation unit that compensates for constellation distortion of the multi-level modulation included in the digital signal in which an influence of dispersion is compensated for by the compensation unit, and an error correction decoding unit that performs error correction of the digital signal in which the constellation distortion is compensated for.

Embodiments of this disclosure provide a signal transmission apparatus, a carrier phase recovery apparatus and method. By inserting phase modulation signals with variable amplitudes into data modulation signals and performing carrier phase recovery on received signals at a receiving end according to the phase modulation signals, the apparatuses and methods are applicable to communications systems of various modulation formats and are compatible with existing communications systems, and calculation complexity is relatively low. Furthermore, as the amplitudes of the inserted phase modulation signals are variable, the phase modulation signals may be flexibly configured in data modulation signals, to lower redundancy and influence on the system capacity is relatively small.

A phase error detection module includes: a constellation point selector, generating a constellation point selection signal according to a position and a radius of data of an input signal in a constellation diagram; a symbol estimator, selecting a part of all of a plurality of constellation points in the constellation diagram according to the constellation point selection signal, as a plurality of reference constellation points for calculating an estimated symbol corresponding to the data of the input signal, and a quantity of the reference constellation points is smaller than a quantity of all of the constellation points of the constellation diagram; and a phase estimator, calculating an estimated phase error of the input signal according to the data of the input signal and the estimated symbol.

A phase ambiguity processing method and device are provided. The phase ambiguity processing method includes: deciding symbols on a Y polarization state and an X polarization state of a received signal, and mapping to obtain first bit information, where the received signal includes a plurality of first signals; checking and analyzing the first bit information to generate a first check result; judging the first check result to obtain a judgment result as to whether the received signal has phase ambiguity; acquiring at least one of the plurality of first signals in the received signal when the judgment result indicates that the received signal has phase ambiguity; performing phase rotation on the first signal to obtain a second signal; and checking and analyzing the second signal, storing the second signal so that the first signal is replaced with the second signal for decoding processing if a check result is normal.

A coherent optical reception device includes a local oscillation laser that supplies laser light, a coherent optical reception front-end unit that receives a multi-level modulated optical signal, demodulates the optical signal on the basis of the laser light, and converts a demodulated optical signal into an electrical analog signal, an analog-to-digital converter that converts the analog signal into a digital signal, a compensation unit that compensates for an influence of dispersion due to a wavelength or a polarized wave of the optical signal and recovers a carrier phase of the digital signal, a constellation distortion compensation unit that compensates for constellation distortion of the multi-level modulation included in the digital signal in which an influence of dispersion is compensated for by the compensation unit, and an error correction decoding unit that performs error correction of the digital signal in which the constellation distortion is compensated for.