Method and apparatus for efficient determination of channel estimate and baud frequency offset estimate

摘要

A method and apparatus for obtaining a channel estimate and a baud frequency offset estimate for a communications channel in a communications system. The communications system has a transmitter for transmitting to a receiver over the communications channel signals representing data appended to a preamble signal. The preamble signal is provided as a periodic plurality of preamble sequences, each preamble sequence being generated in accordance with: 1 $\frac{1}{32}\sum _{k=0}^{15}{b}_k{b}_{\mathrm{mod}\left(k+n,16\right)}^{*}=\{\begin{array}{c}1,n=0\\ 0,n\ne 0\end{array}.$ A signal representing the periodic plurality of preamble sequences is sent by a transmitter over the communications channel to a receiver and is received at the receiver as a received signal. The received signal is processed to determine from the received signal both a channel estimate in accordance with: 2 $\hat{h}=\frac{1}{64}{B}^H\left(y_1+y_2\right),$ wherein B represents a matrix of preamble symbol values, upsampled by four and zero-filled, and y1 and y2 are column vectors of received samples, and a baud frequency offset estimate Deltafb in accordance with: 3 $S=\sum _{}^{}$