Patent ID: 8472574

Claim:
A receiver for recovering data from Orthogonal Frequency Division Multiplexed (OFDM) symbols, the OFDM symbols including a plurality of sub-carrier symbols, some of the sub-carrier symbols carrying data symbols and some of the sub-carrier signals carrying pilot symbols, the receiver comprising a demodulator arranged in operation to detect a signal representing the OFDM symbols, and to generate a sampled digital version of the OFDM symbols in the time domain, a Fourier transform processor arranged in operation to receive the time domain digital version of the OFDM symbols and to form a frequency domain version of the OFDM symbols, from which the pilot symbol sub-carriers and the data symbol bearing sub-carriers can be recovered, and a detector arranged in operation to recover the data symbols from the data bearing sub-carriers of the OFDM symbols, wherein the receiver includes a noise estimator arranged in operation to generate a long term estimate of noise power in the frequency domain version of the OFMD symbols at a plurality of frequencies, by accumulating an average noise power at the plurality of frequencies from a plurality of the OFDM symbols, and for generating an estimate of a current level of the noise power in the frequency domain version of a current one of the OFDM symbols at the plurality of frequencies, an impulsive noise detector arranged in operation to detect the presence of an impulse of noise in the current OFDM symbol, by comparing the noise power in the current OFDM symbol with the long term noise power at the plurality of frequencies, and to generate an impulse noise flag to indicate that the current OFDM symbol is affected by an impulse of noise if the comparison indicates the presence of an impulse of noise, and the detector is arranged to conceal the effect of the impulse noise on the recovering of the data symbols from the data bearing sub-carriers in response to the generated impulse noise flag, wherein the noise estimator is arranged to generate the long term estimate of noise power in the frequency domain version of the OFMD symbols at the plurality of frequencies, and the current estimate of the level of the noise power in the current OFDM symbol by comparing the pilot sub-carrier symbols with a regenerated version of the pilot sub-carrier symbols, which are known to the receiver.