Hi,
MAC will toggle the NDI irrespective of previous value if it receives dynamic grant. (only incase previous transmission was made be CS-RNTI) and it will deliver new data even if it is NACK.
Without MAC HARQ configuration how MSG3 is receiving ACK/NACK form ENB , As per my knowledge MAC configuration comes after connection request then how this is possible?
How UE sends MSG3 in less grant? Will it wait for NEB to give grant or UE does one more RACH?