At the Baltimore location shown to reporters, Sprint has kept its Wimax routers in a large, ground-level cabinet, next to a separate new LTE cabinet. Inside the LTE cabinet are several rack-mounted LTE routers from Alcatel Lucent.

The LTE cabinet is connected with fiber optic cables and power cables to three sets of LTE antennas mounted on the roof of the building that houses the Polish National Alliance Club and other tenants.

The antennas, from vendor RFS, are arranged to receive and send data in all directions, and can even be tilted and adjusted remotely, Chu said. Each of the three large antennas has eight different antennas inside, four for receiving signals, four for sending signals under the Multiple Input, Multiple Output design that helps give LTE widespread coverage, Sprint said.

Below each antenna on the roof, Alcatel Lucent has installed a Remote Radio Head (RRH) box, containing circuitry that connects to the ground-level routers. Chu said that older network technologies used to put the RRH box inside or near the cabinet at ground-level, but locating the box near the antenna increases "gain" efficiency, or how well a signal is received.

Sprint is working with LTE equipment suppliers Alcatel-Lucent, Ericsson and Samsung nationally, and recently announced it will work with Alcatel-Lucent and Samsung to .