AT&T has revealed in a recent announcement that it is launching Voice-over-LTE (or VoLTE) and HD Voice support in the US. The combination of the two new features announced by AT&T is expected to bring about an improvement in phone calls.

According to the AT&T announcement, the first US markets to receive the VoLTE and the HD Voice support features include Wisconsin, Minnesota, Indiana, and Illinois. The two features will be rolled out in these markets starting May 23.

Though AT&T does not have any public roadmap for the launch of the two features in other regions, that carrier has promised news on a "market-to-market" basis.

Among the handsets which will benefit from AT&T's launch of VoLTE and HD Voice support, the Samsung Galaxy S4 Mini already supports the two features; and the Apple iPhone 5 and iPhone 5s will also probably be eligible. In addition, it is also being assumed that the next-generation iPhone 6 will also likely support the features as well.

In a news release pertaining to the imminent launch of VoLTE and HD Voice features, AT&T said that both the features will together bring about a notable difference in call clarity. Part of the improvement in call clarity will result from noise cancellation technology which will reduce background sounds; thereby making calls "crystal-clear."