A method, network node and wireless device for determining a fixed size resource block assignment in random access response, RAR, scheduling of MSG3 transmission based on at least one of bandwidth part size, slot/non-slot transmission and resource allocation type, are disclosed. According to one or more embodiments, a network node is configured to communicate with a wireless device. The network node includes processing circuitry configured to determine a fixed size resource block, RB, assignment for random access response, RAR, scheduling of an uplink transmission based at least in part on at least one of: whether the uplink transmission is one of slot and non-slot transmission, resource allocation type, and optionally indicate the fixed sized RB assignment to the wireless device.