A circuit for processing Carrier Aggregation (CA) is provided. The circuit includes a plurality of Component Carrier (CC) processors, each CC processor configured to estimate a frequency offset for a related CC and to compensate the estimated frequency offset, a reference clock generator configured to generate a reference clock using a reference frequency offset as one of frequency offsets output from the plurality of CC processors, a plurality of reception Phase Lock Loop (PLL) units, each reception PLL unit configured to generate a reception carrier frequency for the related CC corresponding to the reference clock, and a plurality of transmission PLL units, each transmission PLL unit configured to generate a transmission carrier frequency for the related CC corresponding to the reference clock.

Aspects of the subject disclosure may include, a system for receiving first electromagnetic waves that propagate along a physical transmission medium. The first electromagnetic waves can convey first signals in a first frequency range and second signals in a second frequency range, whereby a first spectral location of the first frequency range exceeds a second spectral location of the second frequency range. The system can further perform frequency converting of the first signals in the first frequency range to a first updated frequency range, frequency converting the second signals in the second frequency range to a second updated frequency range and generating second electromagnetic waves that propagate along the physical transmission medium and that convey the first signals in the first updated frequency range and the second signals in the second updated frequency range. Other embodiments are disclosed.

A gaussian frequency shift keying (GFSK) detector comprising a multi-symbol detector; at least three Viterbi decoders, and a timing adjustment module. The multi-symbol detector receives a series of samples representing a received GFSK modulated signal which comprises at least three samples per symbol; and generates, for each set of samples representing an N-symbol sequence of the GFSK modulated signal, at least three sets of soft decisions values, each set of soft decision values indicating the probability that the N-symbol sequence of samples is each possible N-symbol pattern based on a different one of the at least three samples of a symbol being a centre sample of the symbol. Each Viterbi decoder generates, for each N-symbol sequence, a path metric for each possible N-symbol pattern from a different set of soft decision values according to a Viterbi decoding algorithm. The timing adjustment module generates a timing adjustment signal based on the path metrics generated by the Viterbi decoders to adjust the sample timing.

A Gaussian frequency shift keying (GFSK) detector for decoding a GFSK signal. The detector includes: a multi-symbol detector and a Viterbi decoder. The multi-symbol detector is configured to: receive a series of samples representing a received GFSK modulated signal; and generate, for each set of samples representing an N-symbol sequence of the GFSK modulated signal, a plurality of soft decision values that indicate the probability that the N-symbol sequence is each possible N-symbol pattern, wherein N is an integer greater than or equal to two. The Viterbi decoder is configured to estimate each N-symbol sequence using a Viterbi decoding algorithm wherein the soft decision values for the N-symbol sequence are used as branch metrics in the Viterbi decoding algorithm.

A frequency difference compensation unit (510) generates a carrier recovery signal by compensating for a frequency difference between a local light beam and an optical signal in a plurality of digital signals. A first symbol determination unit (521) determines the symbol position of the carrier recovery signal in which a frequency difference is compensated for, in accordance with the signal arrangement of multi-value modulation. A second symbol determination unit (522) determines the symbol position of the carrier recovery signal in which a frequency difference is compensated for, in accordance with a signal arrangement in which the number of multi-values of the multi-value modulation is reduced. A loop filter unit (540) and a compensation signal generation unit (550) temporarily generates a compensation signal using a determination result of the second symbol determination unit (522), and then regularly generates the compensation signal using a determination result of the first symbol determination unit (521).

According to an example implementation, a method for frequency offset reporting includes transmitting, by a first transceiver, a first tracking reference signal to a user device in a wireless communication system, transmitting, by a second transceiver, a second tracking reference signal to the user device, receiving, by the base station, a channel state information (CSI) reporting signal via an uplink channel, where the CSI reporting signal includes power estimation information. The method includes determining whether to pre-compensate a frequency of a downlink signal with frequency offset information based on the power estimation information, and transmitting, by at least one of the first transceiver or the second transceiver, the downlink signal with the pre-compensated frequency in response to the determination to pre-compensate the frequency of the downlink signal.

A method for frequency and time synchronization with respect to a satellite, the method including: calculating a frequency offset ({circumflex over (f)}.sub.B,e) due to an instability of a satellite oscillator from a beacon signal (f.sub.B,TX.sup.N); determining a Satellite Motion Doppler Correction for Ephemeris (SMDC.sub.e) of a satellite motion based on ephemeris data for the satellite; computing a Satellite Reference Drift Correction for Ephemeris (SRDC.sub.e) based on the frequency offset, the beacon signal and the SMDC.sub.e; setting a loopback TX frequency based on the SMDC.sub.e and the SRDC.sub.e; and transmitting a loopback TX signal to the satellite at the loopback TX frequency.

On-chip spread spectrum characterization including obtaining, from a skitter circuit, skitter data comprising a spread width corresponding to an amplitude of a spread of a spread spectrum clock signal; setting an offset pointer to a center of the spread width corresponding to the amplitude of the spread; retrieving, for each of a number of reference clock cycles, edge data indicating a location, within the spread width, of an edge of the spread spectrum during the reference clock cycle; incrementing, using the edge data, an offset counter for each reference clock cycle during which the edge of the spread spectrum crosses the offset pointer; and calculating a frequency of the spread spectrum using the offset counter and the number of reference clock cycles.

Calibrating a Gaussian frequency-shift keying modulation index includes generating a training sequence of bits, shaping a pulse from the training sequence according to an initial modulation index, and converting the shaped signal to a transmission signal. The transmission signal is then either looped through a radio frequency core or processed by frequency deviation estimation hardware to determine a frequency deviation. The frequency deviation is converted to a new modulation index, and potentially a ratio between a target modulation index and a measured modulation index as a scaling factor. The process is then iteratively repeated until a threshold frequency deviation is achieved.

A method improves the transmission quality between a data collector and a plurality of metering units. A first communication module is assigned to the data collector and a second communication module is assigned in each case to a metering unit. The second communication module transmits data via radio signals to the first communication module. The first communication module has a first frequency reference device and the second communication module has a second frequency reference device. The radio signals transmitted are dependent on the second frequency reference device. The measurement of a parameter of the radio signal is performed by the first communication module. An estimation of an error of the second frequency reference device on the basis of the parameter measured values is determined. An adjustment of the frequency of the first frequency reference device is performed such that the error is reduced.