Question: Upon receiving a NACK on the Acquisition Indication Channel (AICH), what action does the User Equipment (UE) take regarding preamble transmission, and after what period does it initiate the second ramping cycle?
Option 1: Immediately stops transmitting preambles and starts the second ramping cycle after a 100 ms pause following the NACK reception.
Option 2: Continues transmitting preambles at a reduced power and initiates the second ramping cycle without any specified pause after the NACK.
Option 3: Stops transmitting preambles, waits for the back-off timer (TB01) to expire, and then starts the second ramping cycle immediately after the 100 ms period post-NACK.
Option 4: Delays stopping preamble transmission until the completion of the current ramping cycle and only then observes a 100 ms silence before restarting.
Explanation: Upon receiving a NACK on the AICH, the UE stops transmitting preambles. The correct sequence involves an immediate halt in preamble transmission followed by a silent period. After the NACK is received, the UE observes a 100 ms period without transmission before initiating the second ramping cycle, adhering to the protocol for handling negative acknowledgments in the random access procedure.