126 results about "Sampling frequency offset" patented technology

Disclosed is an apparatus and method for compensating for frequency offset in a wireless communication system using an OFDM system which can compensate for phase change due to carrier frequency offset and sampling frequency offset of data carried on subcarriers. The apparatus includes an FFT window adjustment unit for receiving sampling data when a packet is received, setting a start point of a FFT window at a start point of long training symbols and adjusting a position of the FFT window according to an input window adjustment value, an FFT unit for receiving an output of the FFT window adjustment unit, transforming time-domain symbols into frequency-domain symbols and calculating FFT coefficients, a channel estimation unit for receiving the coefficients from the FFT unit, estimating a channel state and outputting a value for compensating for an estimated value, a channel compensation unit for compensating for the frequency-domain symbols using the output of the channel estimation unit and a phase error tracking and correction unit for receiving an output of the channel compensation unit, detecting a sampling frequency offset and a phase change of a carrier signal and outputting the window adjustment value to the FFT window adjustment unit.

Synchronization method for a multi-carrier transceiver using a filter bank, for example a cosine modulated filter bank, a wavelet packet filter bank or a complex modulated filter bank, the transceiver comprising a transmitter (100) and a receiver (300) able to communicate with each other over a communication channel (200), the method comprising the following steps: sending a periodic and coded training sequence over the communication channel (200) with the transmitter (100), determining in the receiver (300) time alignment information from the received training sequence, performing a coarse synchronization of the receiver (300) to said transmitter (100) using said time alignment information, sending modulated data (1) in data mode over the communication channel (200) with the transmitter (100), pilot signals being multiplexed into said data (1), tracking sampling frequency offset and phase jitter within the receiver (300) using the pilot signals, performing the continuous synchronization of the transceiver with the help of the tracking information determined in the step of tracking. The invention also relates to a multi-carrier transceiver, consisting of a transmitter (100) and a receiver (300),able to perform this synchronization method.

A sampling frequency offset estimation apparatus and method to be applied to an OFDM (orthogonal frequency division multiplexing) system are provided. The apparatus includes an ADC (analog-to-digital converter) sampling a received signal based on a predetermined sampling frequency; a FFT (Fast Fourier Transform) unit transforming the sampled received signal into a frequency domain; a phase calculator calculating phase shifts of pilot subcarriers of the sampled received signal which has been transformed into the frequency domain; a determiner calculating phase shift reaching times at which samples of the pilot subcarriers shift due to the phase shift; a time offset calculator calculating a sampling time offset using the pilot subcarriers, and a frequency offset calculator calculating a sampling frequency offset based on the phase shift reaching times and the sampling time offset.