New radio (NR) transmission opportunity (TxOP) structure having flexible starting points are disclosed for wireless communications. When a typical listen before talk (LBT) procedure is performed, the transmitting node will not know ahead of time when the LBT will pass and, thus, when data transmissions can start. NR systems may include a mini-slot design for accommodating transmission units smaller than a slot. Aspects of the present disclosure provide for flexibly increasing the number of potential starting transmission boundaries depending on when the LBT pass is detected. Alternative aspects of the present disclosure determine the potential starting transmission points using a mini-slot based design, a floating slot based design, or a punctured slot based design with a code block group (CBG) level retransmission mechanism.