Patent ID: 8396174

Claim:
A receiver for detecting and recovering data from Orthogonal Frequency Division Multiplexed (OFDM) symbols, the OFDM symbols including within a repeating time frame a signalling OFDM symbol and one or more data bearing OFDM symbols, the signalling OFDM symbol including a pre-amble guard interval and a post-amble guard interval, the pre-amble and the post-amble guard intervals being formed by copying samples from a useful part of the signalling OFDM symbol in the time domain, the receiver comprising a demodulator which is arranged in operation to detect a signal representing the OFDM symbols, and to generate a sampled version of the OFDM symbols in the time domain, a signalling and guard detector, which includes a correlator comprising a first branch which forms pre-amble correlated samples from the pre-amble of the signalling OFDM symbol, and includes a first moving averaging filter, which is arranged to form pre-amble average correlated samples by averaging a value of a plurality of the pre-amble correlated samples within a moving window, the plurality of pre-amble correlated samples averaged within the moving window corresponding to a temporal length of the post-amble (Tb), a second branch which forms post-amble correlated samples from the post-amble of the signalling OFDM symbol, and includes a second moving averaging filter, which is arranged to form post-amble average correlated samples by averaging a value of a plurality of the post-amble correlated samples within a moving window, the plurality of post-amble correlated samples averaged within the moving window corresponding to a temporal length of the pre-amble (Tc), a combiner, which is arranged to combine the averaged pre-amble correlated samples and the averaged post-amble correlated samples to form output correlation samples, and a post processing detector which is arranged to detect the signalling OFDM symbol from the output correlation samples to identify a timing of the frame from which the data bearing OFDM symbols can be identified.