Patent ID: 8542774

Claim:
A receiver for detecting and recovering data from Orthogonal Frequency Division Multiplexed (OFDM) symbols, the OFDM symbols including pilot data arranged in accordance with a pilot pattern which has been modulated with a unique random sequence, and a guard interval formed by copying samples from a useful part of the OFDM symbol in the time domain, a length of the guard interval for each OFDM symbol corresponding to one of a plurality of predetermined lengths, the receiver comprising a demodulator operable to detect a signal representing the OFDM symbols and to generate a sampled version of the OFDM symbols in the time domain, a symbol synchronisation unit comprising a plurality of correlators into each of which a same sampled OFDM symbol is concurrently input and a correlation detect processor, each correlator being operable to auto correlate each sampled OFDM symbol between a length of samples corresponding to one of the plurality of predetermined lengths, the correlation detect processor being operable to determine a time domain start point of each OFDM symbol based on a point at which one of the correlators from the plurality of correlators detects a correlation, a frequency transform processor operable to receive the sampled version of the OFDM symbols and to perform a frequency transform on the OFDM symbols to form a frequency domain version of the OFDM symbols starting at the time domain start point determined by the correlation detect processor, and a coarse frequency offset detector including a pilot data filter and a coarse frequency offset detection processor, the pilot data filter including taps corresponding to a value of the unique random sequence and a spacing of the pilot pattern of the OFDM symbols and arranged to receive as an input the frequency domain OFDM symbols from the frequency transform processor and the coarse frequency detection processor is arranged to determine a coarse frequency offset from an output of the pilot data filter.