In arcades first
According to Siliconera, Guilty Gear Xrd Sign will launch on February 20th in Japanese arcades. After that, Xrd Sign will launch on the PlayStation 3 and the PS4 later this year in Japan. There are no announcements for a localization or for Xbox and Nintendo platforms at this time.
As a side note, the new character named Bedman doesn't talk (because he's always sleeping), and you'll be able to see what he's thinking on-screen. Weird!