It’s a bit counter-intuitive to think of cellular capacity as a limited resource. After all, there is no wire. The reality is, however, that the explosion of smartphones and other cellular-based gadgets during the past years – and expectations that their use will grow exponentially during the next several years – has experts worried.

At the CTIA Wireless IT & Entertainment conference in San Diego this week, the spectrum-scarcity issue was addressed by Federal Communications Chairman Julius Genachowski. According to InformationWeek, he said there is a “looming spectrum crisis.” He added that the FCC has authorized a three-fold increase in spectrum in recent years – the piece was not more specific on the time frame to which he referred – but that growth in demand as high as thirty-fold is expected.

Genachowski says unlicensed Wi-Fi spectrum, tower relocation and repurposing of currently allocated spectrum all are ways to confront the challenge.

The wheels are turning. MobileBurn reports that The CTIA Wireless Association has asked the FCC to open up more spectrum in an effort to spur innovation and competition. The organization pointed to what it calls the “virtuous cycle” in which more spectrum leads to more network capacity, more handsets and more content (and, presumably, applications). Of course, that would lead to a need for even more spectrum.

Genachowski wasn’t the only presenter to discuss spectrum and capacity issues. Techworld reports that the father-and-son team from Qualcomm raised the issue as well. Co-founder Irwin Jacobs and son and current Chairman and CEO Paul Jacobs said that the ability to increase  efficiency in the use of a given piece of bandwidth was about exhausted, a scary prospect with the great increase in demand.

Their answer is to break service areas into ever smaller pieces, which will allow the entire spectrum to be reused. This is one of the main attractions of picocells and femtocells. Indeed, carving big service areas into smaller ones is a valuable approach for a couple of reasons: In addition to spectrum reuse, femotocells and picocells help with the tricky issue of ensuring that 4G signals reach within structures. The higher the frequency, the less able signals are to penetrate walls and other obstructions. Femtocells and picocells generally are located within buildings to alleviate the problem.

Indeed, the cellular industry will be hard pressed to live up to its expectations without meeting the challenge of spectrum scarcity. The smart money says that picocells and femtocells are the best bets for keeping the problem under control.