Noise variance estimation and interference detection is described. In one example, a method of estimating noise variance is described in which the pilots within a received OFDM signal are divided into bands and then a noise variance estimate is calculated on a per-band basis by averaging the noise estimates for those pilots within the band. In some examples, the pilots are divided into bands in frequency and in other examples, the pilots are divided into bands in frequency and time, such that noise estimates from more than one OFDM symbol are used in calculating the per-band noise variance estimates. The noise variance estimate for a pilot is then set to the noise variance estimate for the band which contains the pilot. The noise variance estimate for a data sub-carrier can then be determined by interpolating between the values for the pilots.