Voice calling service over LTE using IMS for signaling and QoS bearers.
Description
Voice over LTE (VoLTE) is the technology for voice calls over LTE networks using the IP Multimedia Subsystem (IMS). It replaces the circuit-switched voice of 2G/3G with packet-switched voice.
VoLTE uses dedicated EPS bearers with guaranteed QoS (QCI=1) for voice packets. It supports HD Voice using AMR-WB codec and enables simultaneous voice and high-speed data.
Purpose & Motivation
VoLTE was introduced to:
- Provide voice services on LTE-only networks - Enable HD Voice quality (wideband audio) - Allow simultaneous voice and data - Utilize spectrum more efficiently than CSFB - Enable rich communication services (RCS)
Key Features
- ✓HD Voice (AMR-WB)
- ✓QoS-guaranteed bearer (QCI=1)
- ✓Simultaneous voice+data
- ✓Rich calling features
- ✓SRVCC for CS fallback