An indication can be received at a device from a network. The indication can request the device to feedback channel state information corresponding to a first transmit time interval length operation and/or a second transmit time interval length operation. When the indication requests channel state information feedback for the first transmit time interval length operation: a first reference transmit time interval of a first transmit time interval length can be determined based on the transmit time interval in which the indication is received. When the indication requests channel state information feedback for the second transmit time interval length operation: a second reference transmit time interval of a second transmit time interval length can be determined based on the transmit time interval in which the indication is received.