Embodiments of the present disclosure relate to methods and apparatuses for uplink transmission without an uplink grant. In example embodiments, a method implemented in a terminal device in a communication system is presented. According to this method, the terminal device determines a redundancy version (RV) pattern for a plurality of uplink transmissions. The RV pattern indicates a plurality of RV indices. At least one RV index in the respective plurality of RV indices is periodic in the RV pattern. The terminal device determines coded bits to be transmitted in the plurality of uplink transmissions based at least in part on the RV pattern. The terminal device transmits the coded bits to the network device in at least one transmission of the plurality of uplink transmissions without an uplink grant. By utilizing this periodic structure of the RV pattern, the network device may have more chance to receive the predefined or configured RV index with self-decodable transmissions for example, leading to a higher reliability and better decoding performance for the grant-free communication systems.