Question: How are predefined sounds handled in SMS, according to 3GPP specifications, when it comes to their transmission over the air interface?
Option 1: Predefined sounds are fully transmitted over the air interface in their audio format.
Option 2: Only a reference to predefined sounds is sent, with the actual sound stored locally on the User Equipment (UE).
Option 3: Predefined sounds are compressed and then transmitted over the air interface to save bandwidth.
Option 4: A combination of both sound identification and partial audio data is transmitted for predefined sounds.
Explanation: According to the specifications, predefined sounds are not transferred over the air interface in their entirety. Instead, only their identification is sent. This implies that the actual audio for these predefined sounds is stored locally on the User Equipment (UE), and the UE plays the sound based on the received identification. This approach saves bandwidth and facilitates quicker message delivery.