New high-quality voice service for mobile networks

摘要

The ongoing evolution of wireless communication systems and mobile phones has given rise to a variety of compelling mobile applications (music player, camera, game console) and services (mobile internet, mobile TV, and so on). Likewise, many services have evolved significantly in order to satisfy user demands. In contrast, from a user perspective, voice telephony has not changed noticeably since mobile telephony was still very young. Notwithstanding, voice service has continued to evolve. Significant milestones include the introduction of the enhanced full-rate codec (EFR) and, later, the adaptive multirate (AMR) voice codec, which increased voice quality and boosted channel error robustness and capacity. The narrowband AMR (AMR-NB) codec, which supports the bandwidth of traditional telephony, is now widely deployed in GSM/EDGE and UMTS systems. It is also the codec of choice for the forthcoming multimedia telephony service for IMS (MTSI) standard from 3GPP. As one would expect, AMR also continues to evolve. The new wideband AMR (AMR-WB) codec, whose voice frequency band is twice that of AMR-NB, enables telephony services with true, natural voice quality, clearly outperforming other existing mass-market telephony services, including those used for wireline telephony.