The Small Cell Forum industry group says setting up just four small cells within the area of a macro cell can offload 56 percent of the data traffic from the nearest tower. All this requires exactly the same amount of spectrum as the carrier used to operate the original cell tower, and it lets more subscribers use the network simultaneously.

2. LTE-Advanced

The next generation of LTE is actually a variety of new features coming in version 10 of the standard, which is now complete and is expected to be deployed starting next year. Though it draws attention for its theoretical of 100Mbps (bits per second), the enhancements in LTE-Advanced are mainly for efficient use of spectrum, according to Arne Schaelicke, a global LTE product marketing executive at Nokia Siemens Networks. The advances include the ability to use more antennas per cell and a mechanism to manage interference between macro and small cells.

LTE cells have been limited to just two antennas, but with the new standard they can be configured with as many as eight, to create eight separate streams of data for higher throughput. To allow macro and small cells to work in the same area, LTE-Advanced provides a way for the two types of cells to back off from each other once every millisecond so they can use the same frequency and not interfere with each other, Schaelicke said.

3. Carrier aggregation