One of the 'next big things' is not coming from Samsung, but your carrier and it is called VoLTE (Voice over LTE) calling, HD Voice, Advanced Calling or whatever you want to name the technology. This will bump up the call quality so much that it will seem as though you are speaking to someone directly beside you rather than communicating through a device. P3 Communications conducted tests in late April and early May in Washington, D.C. on Verizon, AT&T and T-Mobile's networks (U.S. Sprint has not yet launched VoLTE) and concluded two things. The first being that there was a significant improvement in voice/sound quality when talking over VoLTE and secondly, all carriers have plenty of work ahead of them to provide VoLTE-to-VoLTE between carriers and international VoLTE roaming.
The testing was done over a two-week period and included driving around inside and outside the I-495 beltway that surrounds the city for more than 1,300 miles. Calls were made between two test vehicles, they made around 7,000 calls and collected more than 50,000 speech samples to compare the real-world performance of both the legacy circuit-switched networks and the new VoLTE networks. They focused on call quality and clarity as well as setup times, the reliability of VoLTE calls and how long the callers stayed connected. Speech quality was measured on what P3 calls a "Mean Opinion Score (MOS) on a scale of 1 and 4.75, with a higher number meaning a better score.
AT&T and Verizon, which do not use AMR wideband or HD Voice technology in their networks showed the most improvement from a legacy to VoLTE call, with Verizon coming out on top with an MOS score of 3.60, followed closely by AT&T with 3.55 and T-Mobile with 3.54. P3 CEO Dirk Bernhardt told FierceWireless, the difference in voice call quality over VoLTE "was very, very minor and statistically not really relevant and not really perceptible by the end user. The improvements are really remarkable, especially if you look at where some of the carriers come from. Anything beyond a 0.5 increase is really recognizable by humans."
The biggest concern is for Verizon, who must use only their VoLTE system when making calls – they do not hand-off to their old CDMA network, so if you get out of range of their LTE network your call will drop…hence their desire to build out their LTE network before anyone else. AT&T and T-Mobile hand off VoLTE calls to their legacy networks using Enhanced Single Radio Voice Call Continuity (eSRVCC) when their callers travel outside their LTE coverage. Bernhardt said, "It forces Verizon to have a much better contiguous network coverage," adding that the carriers "have slightly different philosophies about rolling out VoLTE." He also said that based on what they have seen, they believe Sprint should be able to achieve high-quality voice as well once their VoLTE networks are up and running.