Disclosed is a method and apparatus to detect an intended packet by a sliding intermediate frequency (SIF) coherent ultra low power (ULP) wireless receiver. The method includes detecting a transition from a noise period to a signal period in a pair of input sequences received, dynamically adjusting a gain of the pair of input sequences in response to the signal period being initiated, distinguishing an intended packet from packets received in preambles included in the pair of input sequences, and compensating for a carrier frequency offset of the intended packet in the signal period.