The effects of interference are mitigated in a wireless system through update noise variance estimates. Noise variance estimates may be update after the reception of a preamble in an OFDM receiver. Noise variance estimates may include averages of signal energy over multiple symbols in one OFDM tone and over multiple OFDM tones. A co-located wireless personal area network (WPAN) interface may signal its presence a wireless local area network (WLAN) interface, which may select a noise variance estimate algorithm based therein.