
Sprint Spark allows tri-band devices, like Galaxy S 4, to support active hand-off mode between 800MHz, 1.9GHz and 2.5GHz and provide data session continuity as the devices move between spectrum bands.
Sprint plans to deploy Sprint Spark in about 100 of America’s largest cities during the next three years, with initial availability in five markets now. The first markets with limited availability are New York, Los Angeles, Chicago, Tampa and Miami. Sprint 4G LTE service is expected to be available by mid-2014 to approximately 250 million Americans, and Sprint expects 100 million Americans will have Sprint Spark or 2.5GHz coverage by the end of 2014.
Performance-wise, Sprint Spark promises 50-60 Mbps with the potential to deliver over 2 Gbps downstream in the future given Sprint’s spectrum assets.
http://newsroom.sprint.com/news-releases/sprint-debuts-samsung-galaxy-s-4-with-the-benefit-of-sprint-spark.htm