Certain aspects of the present disclosure provide an apparatus for wireless communications. The apparatus includes a processing system configured to generate a frame comprising a first channel estimation sequence for transmission via a first channel, a second channel estimation sequence for transmission via a second channel, and at least a first portion of a data payload for transmission via a third channel, wherein the first channel includes a first frequency band, wherein the second channel includes a second frequency band different from the first frequency band, and wherein the third channel includes a third frequency band that overlaps in frequency with the first and second frequency bands; and an interface configured to output the frame for transmission.