In at least one embodiment of the invention, a method for reducing a dynamic range of a received radio frequency signal includes receiving digital IQ signals corresponding to an in-phase component of the received radio frequency signal and a quadrature component of the received radio frequency signal. The method includes demodulating the digital IQ signals to generate an instantaneous frequency signal. The method includes selecting a center frequency of a selectable filter according to whether an interfering signal is detected in a target frequency band of the received radio frequency signal. The center frequency is selected from a predetermined frequency and an estimated center frequency determined using the instantaneous frequency signal. The method includes filtering the digital IQ signals using the selectable filter configured using the center frequency to generate output digital IQ signals.

A method and apparatus for determining a position of a frequency domain of a direct current component, a storage medium, a terminal, and a base station are provided. The method includes: receiving a transmission resource for an uplink transmission; determining an uplink signaling of the DC component, wherein the uplink signaling includes a BWP ID and a position of a frequency domain of a first DC component; and reporting the uplink signaling in the transmission resource for enabling a base station to determine whether the position of the frequency domain of the first DC component is located in uplink carrier of an UL or uplink carrier of a SUL based on the uplink signaling and a carrier determination information.

Systems and methods are directed to low cost and low power carrier frequency offset (CFO) estimation in a receiver. In-phase (I) and quadrature (Q) samples of a wireless signal are received by the receiver and a first phase and a second phase are extracted from the outputs of a first autocorrelator with a first time-lag and a second autocorrelator with a second time-lag. The extracted first and second phases are combined to generate an estimated CFO of high accuracy and wide estimation range.

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.

Described herein are techniques related to transmitter precoding for optimizing positioning performance. The techniques are directed to transmit signals with relatively higher transmission power, in a direction along the line of sight between the transmitter and the receiver, than signals transmitted in other directions. The techniques render the first signal arriving at the receiver, as it travels along the line of sight between the transmitter and the receiver, to have stronger signal strength than the signal strengths of other signals that travel through non-LoS paths to reach the receiver.

Joint estimation of the framer index and the frequency offset in an optical communication system are described among various other features. A transmitter can transmit data frames using pilot and framer symbols. A receiver can estimate the framer index and frequency offset using the pilot and framer symbols, and identify the beginning of a header portion of a data frame. By identifying the beginning of the header portion of a data frame, the receiver can then process data received from the transmitter in a manner synchronous to the manner in which the data was transmitted by the transmitter.

Disclosed are a frequency offset estimation method and apparatus in an optical transmission network and a storage medium. The method comprises: acquiring a data symbol to be frequency offset estimated, and eliminating a noise phase, a phase generated by a light source and an information phase in the data symbol to be frequency offset estimated; and performing a correlation operation on a data symbol with a set interval in the data symbol after the elimination processing and using a correlation operation result to determine a frequency offset estimation value.

A method in a receiver includes receiving from a transmitter a signal including at least first and second frames that carry same data. First and second data symbols are identified in the respective first and second frames, wherein the first symbol has a same data value as the second data symbol. A frequency offset between the transmitter and the receiver is estimated based at least on the identified first and second data symbols. A frequency of the receiver is adjusted based on the estimated frequency offset.

A method and apparatus for generating a sampling frequency are provided. A signal is generated, of which frequency is a predetermined multiple of a reference clock, and a frequency offset in a channel is extracted from the entire frequency offset. The amount of shift is calculated by dividing the extracted frequency offset by a predetermined value, and a final sampling frequency is obtained by shifting the frequency of the generated signal by the amount of shift.

A receiving circuit capable of estimating frequency offset includes a front circuit and a calculation circuit. The front circuit receives a remote signal to generate a received signal. The calculation circuit includes: an exponentiation module, calculating an exponent of a power to generate a high-order signal; a frequency-domain transform module, performing frequency-domain transform on the high-order signal to generate a spectrum; a peak searching module, searching for a peak of the amplitude of the spectrum to generate a peak coordinate value reflecting a frequency where the peak occurs; an offset estimating module, adding the peak coordinate value with a compensation value to generate a sum, dividing the sum by a first divisor to generate a remainder, subtracting the compensation value from the remainder to generate a difference, and dividing the difference by a second divisor to generate an offset estimation value reflecting the frequency offset.