engleski

Carrier and Sampling Frequency-Offset Mitigation Method for Multicarrier Systems

In Orthogonal Frequency Division Multiplexing (OFDM) systems, symbols are transmitted in parallel on several narrow-band subchannels, which are overlapping and orthogonal. Modulation and demodulation is achieved by using discrete Fourier transform (DFT) algorithms. Mismatch in carrier and sampling frequencies between transmitter and receiver can lead to serious degradation due to the loss of orthogonality between subcarriers. Therefore, both carrier frequency offset and sampling frequency offset have to be estimated, and the error has to be compensated at the receiver side. In this paper we propose a novel method to mitigate the effects of carrier and sampling frequency offset. The proposed algorithms are designed to operate in the digital domain, on the signal samples, and therefore the receiver can be designed with fixed free-running oscillators. Very high improvement in system performance is confirmed by simulations. Ideal frequency-offset estimates were assumed. Algorithms for frequency-offset estimation and their performance were not discussed in this paper.

DSP application in communications; multicarrier systems; OFDM; carrier frequency offset; sampling frequency offset

nije evidentirano