Erecting more traditional cell sites (whether antennas on pre-existing buildings, or on monopoles or new towers) will only get you so far in terms of system enhancement. Although more sites are deployed every day, just building more traditional cell sites might not solve the issues involved in providing better in-building coverage. Plus, the infrastructure  realities—cost and otherwise—are prohibitive. “People don’t want those antennas in their backyards,” said Dave Kaun, Chief Technology Officer for Elert & Associates, a Minnesota-based technology consulting firm.

So, what are the alternatives for improving in-building coverage? Going from small to big:

Femtocells: These are free-standing base stations that link with a home or office high speed Internet connection. The voice traffic is routed through the Internet, thus improving connection quality and saving money (you don’t use as many cell phone minutes). An apartment complex or office campus could use one; then again, femtocells also can be used at the single-user level. A call can be “handed off” from the macro-cellular network to the femtocell whenever the user steps inside.

“The very walls which are a radio signal’s adversary actually become their friend as they attenuate RF signal propagation out of the home from the femtocell, thereby minimizing radio interference with an existing macrocellular network or another nearby femtocell,” Singh wrote in his article. (See the full text at www.wirelessdesignmag.com.)

In addition to providing good indoor coverage, femtocells also free up capacity in the macro-cellular network, Singh wrote. When a call is “handed off,” it results in one fewer user on the bigger network. That’s a big benefit, especially during peak usage hours.

Singh noted that the environment for significant use of femtocells is good now because:

• The wide proliferation of IP broadband connections provides the necessary “backhaul infrastructure.”
• Integrated custom silicon parts for femtocells are widely available.
• There are more than 2.5 billion wireless subscribers worldwide, so “the economy of scale to justify femtocell deployment is finally in place.”

AT&T Mobility says it is evaluating femtocell technology. Verizon Wireless says it plans a rollout later this year. Sprint Nextel Corp. has gone further, introducing its Airave femtocell product last year in select markets. Experts say 2009 will be the year femtocell technology really hits the consumer market.