A method is provided for minimizing cross-technology interference with data transmissions from a wireless device in a shared spectrum. The wireless device obtains data to be wirelessly transmitted in a transmission burst in a first radio access technology (RAT) format over a shared spectrum. The wireless device generates a preamble comprising assistance information related to the transmission burst. The preamble comprises a first preamble portion in the first RAT format and a second preamble portion in a second RAT format. The wireless device transmits the preamble followed by the transmission burst.