Wireless

About 1.5 million people showed up for President Obama's inauguration, clogging cell phone networks.

(Credit: Marguerite Reardon CNET News/CBS Interactive)

I must admit, I never really saw the point in having TV on my cell phone. That was until Tuesday.

I was one of the lucky people who was able to get to my ticketed-spot on the National Mall to see Barack Obama become the 44th president of the United States. I trekked more than two hours through a sea of people along the streets of Washington, D.C., to make it to the "Silver" gate for a standing-room view of the inauguration. And I withstood the freezing temperatures throughout the rest of the day to watch the historic swearing-in ceremony and the parade that followed.

Like the rest of the 1.5 million or so people on the mall and lining the parade route for the inauguration, I was trying to text message and call family and friends to share the moment. I also tried to access mobile Web sites to get updates on what was happening. And of course, being the reporter I am, I wanted to update my Twitter feed to let others know what I was experiencing.

But for most of the day, I had only spotty service on my AT&T iPhone. I couldn't text or make phone calls at all from the Mall before or during the ceremony. And forget about Twittering or checking Web sites for updates. My sister, who uses a basic Verizon Wireless flip phone, also had trouble sending and receiving text messages during the inauguration ceremony.

The only mobile service that worked flawlessly on Inauguration Day for me was MediaFlo's FloTV service offered through AT&T. MediaFlo had let me borrow a Samsung FloTV phone specifically for the inauguration. And even though the public relations representative who lent me the phone hadn't charged it completely and forgot to give me a charger for the device, which greatly limited how much I could use it, the service itself worked without a hitch.

While I was very happy to be standing on the mall at all, it quickly became apparent that my sister, Amy, and I, were not going to see much from our vantage point. Not only are we both short. I am five foot four inches tall, and Amy is about five foot two inches. But we were also too far away to see anything but a tiny speck on the steps of the Capitol.

Standing between tall people, we were able to catch glimpses of the big JumboTron in our section. At first we watched as various congressional leaders and celebrities took their seats, Oprah and Beyonce, and then Sens. Ted Kennedy and John McCain. But we wanted to know where Obama was. So we tuned into live CNN coverage of the event. And sure enough, Wolf Blitzer narrated President-elect Obama's journey from the White House, where he was having coffee with President Bush, to the Capitol where the ceremony was set to begin.

After the swearing-in ceremony, Amy and I found ourselves on Constitution Avenue right near the Capitol. And we decided to continue braving the cold temperatures to wait for the Obamas to finish lunch and start the motorcade toward the White House. Again, I turned on the FLO TV phone to get updates. We had quickly made friends with the four or five people standing near us, including an MSNBC news crew. None of us thought much of the ambulance that barreled up Independence Avenue toward the Capitol. It wasn't until I tuned into CNN again on the FLO TV phone that we learned that Sen. Kennedy had collapsed at the congressional lunch. We then huddled together in the cold, watching and listening to President Obama's remarks after the lunch. And just before the phone ran out of battery power, we learned the motorcade was set to begin.

How the FLO TV signals got through
So why did AT&T's FLO TV service work so well for me while its regular phone, text, and data service on my iPhone performed poorly? Well, there's a very simple explanation. My iPhone operates over AT&T's regular cell phone network. And the FLO TV service operates over MediaFlo's owned and operated TV broadcast network. MediaFlo, which is owned by wireless chipmaker Qualcomm, has built a mobile TV broadcast network using wireless spectrum that is currently being used to broadcast analog TV signals in Channel 55.

The company has negotiated with broadcasters in certain markets, and is already offering the service in 56 markets. It will offer the service nationwide in February after TV broadcasters stop transmitting in analog and switch solely to digital.

AT&T and Verizon Wireless resell the FLO TV service, which offers between 11 and 13 channels of broadcast and cable TV programming for $15 a month.

Because MediaFlo's mobile TV network is built as a broadcast network, it can handle large volumes of people accessing content at the same time. The live TV channels are broadcast over the wireless spectrum and viewers "tune in" with their handsets. This approach, used in traditional broadcast television and radio, means that video clips are transmitted only once over the network, instead of being replicated and transmitted hundreds or even thousands of times.

By contrast, voice, text, and data services use AT&T's traditional wireless network, which is built for two-way communication. These networks are divided into cells. Users in a given cell share the available bandwidth. The networks are also designed to be "unicast," which means signals are transmitted between a single sender and a single receiver.

So If 500,000 people in the same cell decide to send a text message, access the Web, or make a phone call at the same time, the network becomes congested and delays text messages, drops calls, or refuses Web connectivity.

AT&T and other wireless operators spent millions of dollars upgrading their networks in anticipation of huge crowds for the inauguration. But because there were so many people packed into Washington, D.C., and in particular around the Capitol and National Mall on Tuesday, the traditional cell phone networks still became congested and didn't perform optimally.

Just to give a sense of the amount of traffic traversing the network on Tuesday, John Taylor from Sprint Nextel said that the volume of voice, text, and data traffic on its CDMA network had broken all previous records by 6 a.m. There was a 212 percent increase in traffic volume from 11 a.m. to 12 p.m., just before the inauguration ceremony began.

AT&T's spokesman Mark Siegel said between 11 a.m. and 12 p.m. text messaging volumes increased six-fold on AT&T's network. Mobile Web access was also way up during this period, Siegel said. But he admitted that there were some problems.

"We feel like the network performed great," he said. "Was it perfect? No, there were occasions when people couldn't get through. That really was no surprise given the number of people that were in such a small area."

Surprise or not, I was happy to have the FLO TV phone. And even though I still think $15 a month is too much to spend on top of my already pricey cell phone plan, I would be tempted to consider it. How about you? I'd love to hear reactions from readers. Would events like the inauguration tempt you to spend more money on a broadcast style mobile TV service?