Question: For IMS (IP Multimedia System) terminals supporting wideband speech at a sampling frequency of 16 kHz, which speech codec is required to be supported according to 3GPP specifications?
Option 1: Adaptive Multi-Rate Wideband (AMR-WB) codec
Option 2: Adaptive Multi-Rate (AMR) codec for narrow-band speech only
Option 3: Enhanced Full Rate (EFR) codec
Option 4: GSM Full Rate (FR) codec
Explanation: The AMR-WB (Adaptive Multi-Rate Wideband) codec is specifically designed for wideband speech, operating at a higher sampling frequency of 16 kHz, which provides better voice quality compared to narrow-band codecs. According to the specifications, when IMS terminals support wideband speech at this frequency, supporting the AMR-WB codec is mandatory to ensure compatibility and optimal audio performance in multimedia communications.