Apparatus and methods are provided to enhance HARQ mechanism. In one novel aspect, the UE decodes resource blocks in a HARQ indicator channel and detects a single-state HARQ indicator encoded with a UE ID of the UE. The UE determines a HARQ acknowledgment status for the data transmission based on the HARQ indicator. In one embodiment, the HARQ indicator channel is either a UE-specific channel, a group-specific channel or a cell-specific channel. In another novel aspect, the UE increases a HARQ count upon decoding the HARQ indicator channel. The UE retransmits the data transmission if the HARQ count is smaller than a predefined maximum HARQ count and the HARQ acknowledgement status is determined to be negative. Otherwise, the UE stops the data transmission. In another embodiment, the UE terminates the data transmission is the total repetition number is greater than a predefined maximum data transmission number.