All Sprint requires is a new BRS/EBS antenna and a dual mode TD-LTE / Wimax RRU of which Samsung can support 80mhz of spectrum or 4x 20mhz carriers or 2x 20+20mhz carrier aggregated channels.
The Samsung MMBS (and other cabinets by other vendors) are modular and can accept any and all equipment or technology be it iden, hspa, lte, wimax, td-lte, etc with the proper additions to the base station.
Adding TD-LTE gear to existing Network Vision sites will be very simple. When that occurs in a few months, the majority of Network Vision sites will be active with LTE and upgraded fiber backhaul. All that will be required is addition of Antennas & RRUs with corresponding hybrid fiber cables to connect & power said antennas alongside some minor additions to the base station to enable said technologies.