20110044406 | SIGNALLING METHOD AND APPARATUS USING FREQUENCY PILOTS BASED ON COMPLEMENTARY SEQUENCES - The invention relates to a signalling method using orthogonal frequency division multiplexing (OFDM), based on a preamble comprising N dedicated carriers (frequency pilots), the position and modulation of which is defined by one or more concatenated complementary sequences of length N. Complementary sequences are those for which the sum of the autocorrelations thereof is zero except for zero shift, i.e. a KrĂ¶necker delta. The main purpose of said preamble is to signal the basic properties of the transmitted signal and to provide a first estimation at the moment of time and frequency synchronisation. The preamble is multiplexed or sequenced temporally with the transmitted data using OFDM prior to the application of the inverse Fourier transform by the inverse fast Fourier transform (IFFT) block. | 02-24-2011 |