Estimation algorithm of interference frequency offset in PCMA system

For cooperative received Paired Carrier Multiple Access (PCMA) signals, a new algorithm for frequency offset estimation is proposed. The local sample sequence is used as auxiliary data, and frequency offset is estimated based on the discrete Fourier transform (DFT) of the autocorrelation of the sequence, which obtained by multiplying the auxiliary data and mixed signal. The modified Cramer-Rao Bound (MCRB) of frequency offset is derived, which provides a theoretical basis for the performance evaluation of the proposed algorithm. The simulation results show that, compared with the M&M algorithm, the proposed algorithm gain a lower signal to noise ratio (SNR) threshold. It is very suitable for frequency offset estimation of PCMA signal in a low SNR.