Editor's note: Amy Gahran writes about mobile tech for CNN.com. She is a San Francisco Bay Area writer and media consultant whose blog, Contentious.com, explores how people communicate in the online age.
(CNN) -- Can wireless carriers' mobile broadband networks keep pace with the fast-growing demand for mobile data? Maybe not. The Federal Communication Commission predicts a "looming spectrum crunch" in a recently published paper, Mobile Broadband: The Benefits of Additional Spectrum.
According to FCC Chairman Julius Genachowski, "The explosive growth in mobile communications is outpacing our ability to keep up. If we don't act to update our spectrum policies for the 21st century, we're going to run into a wall -- a spectrum crunch -- that will stifle American innovation and economic growth and cost us the opportunity to lead the world in mobile communications."
The agency predicts that U.S. mobile data users will start feeling the spectrum crunch within five years. Users of smartphones, tablets, PC aircards and MiFi-style routers, and even feature phones (which are adding data capabilities fast) will feel this pinch. It will hinder the speed, quality, performance and reliability of wireless broadband connections.
So much for the much-touted (and so far, generally deserved) "rich user experience" that's been driving demand for smartphones.
Users of iPhones in California's San Francisco Bay Area and several other metro regions have found out in the last several years what a spectrum crunch feels like. When a carrier like AT&T faces a far greater demand for data than its network hardware can deliver, users end up waiting and waiting for Web pages, maps, apps and more to update. E-mails take a long time to download, and sending photos or video slows to a snail's pace.
Your smartphone ends up feeling like an expensive, fancy turtle, especially in peak locations or at peak times.
For me, AT&T's ongoing Bay Area spectrum crunch was a key reason why this summer I switched from an iPhone to a Droid Incredible, which offers much snappier performance, largely due to relatively low congestion on Verizon's network here. (So far).
How fast is U.S. mobile data usage growing? According to the FCC, "In just the latest six months of FCC reporting, subscriptions to mobile data services increased by 40 percent." Also, from the first quarter of 2009 through the second quarter of 2010, the amount of data used by wireless consumers grew by more than 450 percent. Within five years, FCC expects mobile data demand to grow from 25 to 50 times current levels.
Fixing the spectrum crunch means upgrading carriers' network technology and letting those networks operate on new frequencies. The FCC regulates which parts of the spectrum get to be used for which purposes, so in an attempt to mitigate the spectrum crunch, the FCC's National Broadband Plan calls for freeing 300 megahertz of spectrum "suitable for mobile-flexible use" within five years. This should, says the FCC, add at least $100 billion in value to the U.S. economy over the next five years.
Will it help that U.S. carriers are starting to switch to faster 4G and LTE network technology? Yes, but probably not enough, says FCC.
Most U.S. carriers rely primarily on a mix of 2G and 3G technology. Through 2014, carriers are shifting to primarily a 3G/4G technology mix, which FCC says should "effectively double the average spectral efficiency of wireless networks." However: "Even when accounting for this factor it is clear that additional spectrum will be needed to meet mobile data demand."
Wireless carriers are starting to roll out some 4G and LTE networks. However, you'll need a phone capable of operating on these networks in order to benefit from them. While more and more higher-end smartphones like the HTC EVO are 4G-enabled, most of the mobile phones in use in the United States cannot access a 4G network. This is especially true of feature phones.
The bottom line: In order to enjoy the benefits of a faster, less congestion-prone mobile network, you'll probably need to buy a new phone -- probably a more costly one. Also, expect data plans to get more costly. One way carriers curb demand for mobile data is to make it more expensive, which is why AT&T introduced tiered data plans earlier this year.
If the economic recovery continues its slow pace, that's likely going to be a hard sell for many U.S. consumers.
So, if right now you have fast, reliable mobile broadband, enjoy it while -- and where -- it lasts. We may well be heading for leaner times, when streaming videos to your phone, tethering your laptop or playing mobile multiplayer games on your tablet might get far more difficult and expensive.
While the spectrum crunch lasts, lower-bandwidth sites, apps, services and content might look more attractive to more consumers. So keep an eye out for simpler mobile services and entertainment. You may need them.
The opinions expressed in this commentary are solely those of Amy Gahran.