The new international standard IEEE802.11p (WAVE) defined enhancements to IEEE802.11 (Wi-Fi). A new mobile e-business platform of Wi-Fi and WAVE is described. Based on cognitive radio, the popular wireless network Wi-Fi can collaborate with WAVE in their common unlicensed spectrum band and licensed spectrum band. As a core technology in the cognitive radio field, OFDM is introduced, and a novel frequency estimation algorithm for them is presented.