Embodiments described herein provide apparatus and methods for performing HARQ operations using parallel HARQ threads, where each new transmission of a Media Access Control (MAC) Protocol Data Unit (MPDU)/Aggregate-MPDU (A-MPDU)/Physical Layer Convergence Procedure (PLCP) Service Data Unit (PSDU) triggers the activation of a HARQ thread. Each HARQ thread contains one or more HARQ coding words or coding units. A HARQ thread index is setup by a transmission opportunity (TXOP) holder for a corresponding PSDU and is used to identify HARQ threads. Transmission information such as duration in formation for PPDUs including BA/HARQ-ACK feedback such as RX/TX addresses, etc. can be determined according to previous transmission values of a received PPDU (e.g., values of a MAC or PHY header).