Sprint actually had SVDO & SVLTE on several of their phones, including the Note 2, Galaxy S2 [SV-Wimax?] and Galaxy S3. Newer phones that are tri-band compatible don't have the ability to run data and voice at the same time, unless you are on wi-fi. I have read that it has something do with the Qualcomm radios that run all three bands. Supposedly, none of the "Spark" compatible phones (G2, Nexus 5, S4) will support it either.
When I found out, it was almost a deal breaker on the G2. Then I found out all the newest phones have the same problem, so I stuck with my G2 anyway.