(CNN) -- What happens when 900,000 people gather in one place and try to make cell phone calls, or post photos to Facebook? Busy signals, dropped calls, and photo and video messages that never go through.
That's a concern of wireless phone carriers, who have been busy prepping for President Obama's second presidential inauguration in Washington. The event culminates Monday, when an estimated 900,000 people will crowd the U.S. Capitol and the National Mall for Obama's swearing-in ceremony and inaugural parade.
The crowd is expected to be much smaller than it was four years ago, when 1.8 million people turned out, but the data demands on Washington's networks will be higher, at least per person.
Since January 2009, a lot of people have upgraded to smartphones with powerful built-in cameras. Four years ago, smartphones only accounted for 11% of global smartphone sales, according to Gartner. In the third quarter of 2012, the smartphone accounted for 39.6% of phone sales around the world.
All those more powerful phones mean the chance to share juicier content with friends who didn't make it to the inauguration. According to Verizon Wireless, data usage in D.C. has increased 12-fold since the last inauguration in 2009.
So to meet the increased demand, the major carriers are spending a lot of money to beef up their networks in the nation's capital.
"We've increased our overall wireless capacity on the National Mall by 200% during the inaugural celebrations," said AT&T spokesperson Mark Siegel.
AT&T is deploying temporary mobile cell towers, called COWS (cell on wheels), and adding high-powered amplifiers to its rooftop antennas, which will allow more devices to connect to the network. (Even though it's a wireless network, the signals actually travel over wires between cell sites, and AT&T has added more fiber and copper to boost data speeds.)
Since 2009 Verizon has rolled out its faster 4G LTE network in the Washington area and increased capacity there by 2.5 times, according to spokesperson Melanie Ortel. She said Verizon also has built new network infrastructure and will also deploy temporary COWS along the Mall and surrounding areas.
Sprint will roll out three of its own COWs for the day, and is boosting its networks in major hotels around the city to serve the throngs of guests. The company says it has been working on its D.C. area service since last April, improving cell sites so its network can handle 37% more data.
Finally, T-Mobile says it has been working on improving its D.C.-area coverage as well as part of a $4 billion national plan. In November, the company installed new equipment in Washington and surrounding cities, and "re-tuned" its 4G airwaves to support a higher volume of devices.
So, if you're going to be in Washington for the inauguration -- or for some other reason -- here are a few ways you can improve your chances of sending or receiving messages from your phone.
-- Be smart about what method of communication you pick. According to Sprint, a person can send about 30-50 text messages in the 180 seconds it takes, on average, to hold a voice call.
-- Don't go overboard with photos and videos. Sharing a photograph or video of the first family puts a lot more strain on the network than sending a text message that simply reads, "OMG just saw FLOTUS." A 2-megabyte photo is going to require a lot more bandwidth.
-- If you simply must share a photo, use any in-camera settings you may have to compress it to the smallest possible size (many tools like Instagram automatically shrink your images).
-- Better yet, save the image for later and stick to text messages, which leave the smallest strain on the network and are the most likely to go through.
Wireless networks aren't the only option for people on the Mall. There are also numerous free Wi-Fi hotspots along the parade route, and the city offers free Wi-Fi coverage. To see a map of the city's Wi-Fi hotspots, check out wifi.dc.gov.
When all else fails, the city still has scores of payphones. Those calls should go through easily.