Method and device for maximum likelihood frequency offset estimation based on joint pilot frequency

The invention discloses a method and a device for maximum likelihood frequency offset estimation based on a joint pilot frequency. The method and the device are used for reception synchronization of a multi-input multi-output (MIMO)-orthogonal frequency division multiplexing (OFDM) system. The method comprises the following steps: a receiving end preprocesses a corresponding nth transmission pilot symbol matrix D(n), a discrete Fourier transform (DFT) matrix F, and a matrix W(wavy line) composed of the first L columns of the matrix F to obtain a matrix P(n); the receiving end respectively and correspondingly stores a receiving pilot symbol matrix R(n) and the matrix P(n) in first-in-first-out sliding window memories with the length being M; and M frequency offset matrixes are constructed, the receiving pilot symbol matrix R(n) and the matrix P(n) are acquired from the sliding window memories, a likelihood function is calculated according to the receiving pilot symbol matrix R(n), the matrix P(n) and the M frequency offset matrixes, and frequency offset estimation values to be selected are substituted in the likelihood function to obtain a frequency offset estimation value, which makes the accumulation of values of the likelihood function minimum, as the final maximum likelihood frequency offset estimation value.