Method and apparatus for the determination of the channel - and baud frequency offset estimate by means of a preamble with a repeating sequence

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: (I). 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: (II), 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 Δ fb in accordance with: (III), wherein fb is a baud frequency and fc is a center frequency of the transmission signal.