Methods and apparatus for obtaining a response message for CB access uplink transmission are disclosed. In one novel aspect, UE performs a CB access uplink transmission, selects a first group of radio resources for one or more candidate control-less response message blocks with corresponding transmission repetition number, retrieves and decodes one candidate response message block corresponds to one sub-group of resources in the first group of radio resources and determines if the candidate response message is intended for the UE. In one embodiment, the UE obtains the candidate response message by determining one or more repetition number and obtaining corresponding sub-group of resources from the starting point(s). In another embodiment, the UE determines one or more frequency locations to obtain the candidate response message. In yet another embodiment, the UE selects a second group of radio resources if no response message is detected within the first group of radio resources.