Question: In a Channel Aware Mode Encoder for Enhanced Voice Services (EVS), what is the primary purpose of adjusting the Frame Erasure Rate Indicator (FERI) threshold between 'low' (<5%) and 'high' (>5%)?
Option 1: To dynamically switch between different voice codec rates based on network congestion.
Option 2: To control the frequency of partial copy transmission by adjusting the criticality threshold for frame classification.
Option 3: To modify the Partial Redundancy Offset (FEC offset) for optimizing redundant frame retrieval.
Option 4: To trigger a receiver-initiated handover to a different base station due to poor channel conditions.
Explanation: Adjusting the Frame Erasure Rate Indicator (FERI) threshold between 'low' (<5%) and 'high' (>5%) in a Channel Aware Mode Encoder for EVS primarily influences how frames are classified as critical or non-critical. This classification directly impacts the decision on whether to transmit partial redundant copies of frames, thereby controlling the frequency of such transmissions based on perceived channel reliability. This is crucial for maintaining voice quality over unreliable channels by ensuring critical frames have a higher chance of being correctly received.