A distributed radio frequency communication system facilitates communication between a wireless terminal and a core network. The system includes a remote radio unit (RRU) coupled to at least one antenna to communicate with the wireless terminal. The RRU includes electronic circuitry to perform at least a first portion of a first-level protocol of a radio access network (RAN) for communicating between the wireless terminal and the core network. The system also includes a baseband unit (BBU) coupled to the core network, and configured to perform at least a second-level protocol of the RAN. A fronthaul link is coupled to the BBU and the RRU. The fronthaul link utilizes an adaptive fronthaul protocol for communication between the BBU and the RRU. The adaptive fronthaul protocol has provisions for adapting to conditions of the fronthaul link and radio network by changing the way data is communicated over the fronthaul link.

A method at a receiver comprises receiving a signal conveying symbols at respective positions within a clock cycle, the symbols comprising a data set consisting of data symbols and a pilot set consisting of pilot symbols; determining detected phases of the symbols based on the signal; generating first phase estimates based on the detected phases of a subset of the pilot set, and reference phases of the subset of the pilot set, the first phase estimates being associated with the positions of the pilot set; and generating second phase estimates based on the detected phases of the pilot set, reference phases of the pilot set, and the first phase estimates, the second phase estimates being associated with the positions of the pilot set and of at least a subset of the data set; and applying rotations to the detected phases of the symbols based on the second phase estimates.

A distributed radio frequency communication system facilitates communication between a wireless terminal and a core network. The system includes a remote radio unit (RRU) coupled to at least one antenna to communicate with the wireless terminal. The RRU includes electronic circuitry to perform at least a first portion of a first-level protocol of a radio access network (RAN) for communicating between the wireless terminal and the core network. The system also includes a baseband unit (BBU) coupled to the core network, and configured to perform at least a second-level protocol of the RAN. A fronthaul link is coupled to the BBU and the RRU. The fronthaul link utilizes an adaptive fronthaul protocol for communication between the BBU and the RRU. The adaptive fronthaul protocol has provisions for adapting to conditions of the fronthaul link and radio network by changing the way data is communicated over the fronthaul link.

Methods and system for carrier frequency offset (CFO) estimation are described. The method includes determining correlation values between a plurality of samples from a received signal and a plurality of reference signals corresponding to a plurality of CFO candidates. A set of correlation values which exceeds a threshold is determined and a corresponding CFO candidate for each correlation value in the set is selected. A CFO estimate based on an interpolation of selected CFO candidates is then calculated.

The present disclosure relates to a signal processing device and an image display apparatus including the same. A signal processing device according to an embodiment of the present disclosure includes a sampler to downsample a baseband signal; a memory to store the downsampled data; a frequency shifter to read the data in the memory and shift the read data in a frequency domain; a symbol rate calculator to calculate a symbol rate based on the shifted data; a first offset calculator to calculate a first carrier frequency offset based on the calculated symbol rate; a second offset calculator to calculate a second carrier frequency offset based on the calculated first carrier frequency offset; and an offset compensator to compensate for the second carrier frequency offset. Accordingly, a time up to the demodulation completion may be shortened based on the baseband signal.

A mixer in a receiver converts a sounding sequence of alternating ones and zeros to an intermediate frequency signal. A digital mixer converts the intermediate frequency signal to a baseband signal that contains a positive tone and a negative tone. A frequency offset correction circuit generates frequency offset corrections based on frequency offset estimates of the frequency offset between a transmitter of the sounding sequence and the receiver. A frequency adjustment circuit adjusts a frequency of the mixer or the digital mixer to thereby center the positive tone and the negative tone around DC. DFT circuits perform single bin DFTs respectively centered on the positive and negative tones. Phases of the positive and negative tones are calculated based on outputs of the DFT circuits and the phases are used to determine fractional time value associated with a distance measurement between the transmitter and receiver.

Methods and apparatus for processing multichannel signals in a multichannel receiver are described. In one implementation, a plurality of demodulator circuits may provide a plurality of outputs to a processing module, with the processing module then simultaneously estimating noise characteristics based on the plurality of outputs and generating a common noise estimate based on the plurality of outputs. This common noise estimate may then be provided back the demodulators and used to adjust the demodulation of signals in the plurality of demodulators to improve phase noise performance.

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.

A method for determining an angle of arrival (AOA) of a received signal is disclosed, comprising: generating a baseband information signal by mixing a received signal with a local oscillator (LO) signal, the received signal being an in-phase signal and quadrature signal uncorrelated with each other and derived from different input data sets; obtaining baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample; determining a transmitter phase offset based on an estimated correlation between the in-phase signal samples and the quadrature signal samples; performing a plurality of phase measurements using a plurality of antennas to obtain a plurality of phase measurements; correcting the plurality of phase measurements based on the transmitter phase offset to produce a plurality of corrected phase measurement; and calculating an AOA of the received signal based on the difference between the plurality of corrected phase measurements.

A digital radio receiver adapted to receive radio signals modulated using continuous phase frequency shift keying, CPFSK. The receiver comprises means for receiving a radio signal (2), a correlator (8) arranged to estimate a frequency offset between the carrier frequency of the received radio signal and a nominal carrier frequency, means for correcting said frequency offset (4) and outputting a frequency-corrected radio signal (6), and a matched filter bank, MFB, which comprises a plurality of filters (20,22), each of which corresponds to a different bit pattern, for determining a bit sequence (36) from the frequency-corrected radio signal (6).