A method for mobile station accessing to a base station in a wireless communication system that uses selective acknowledgement mechanism, comprising: transmitting, an access probe from the mobile station to the base station; receiving, a message from the base station, wherein the message indicates parts of the plurality of data frames are not decoded by the base station; passing, an instruction from a MAC layer to a PHY layer of the mobile station, wherein the instruction is used to send a selective acknowledgement header; sending, the parts of data frames that are not decoded by the base station from the MAC layer to the PHY layer according to the message; and retransmitting the parts of the plurality of data frames.