techniques for and apparatus capable of implementing packet detection and signal recognition in wireless communications systems are disclosed . in particular , the disclosed techniques and apparatus incorporate at least one of relative energy detection operable on assessment of a relative energy threshold for an inbound signal borne across an rf channel , carrier sense operable upon on assessment of at least one of a peak - to - sidelobe ratio and peak - to - peak distance defined by the inbound signal , and comparison operable upon demodulated data corresponding to the inbound signal as compared to predetermined preamble data . clear channel assessment is performed based on determinations undertaken by one or more of the aforementioned relative energy detection , carrier sense and comparison operations .