While data traffic is growing, signaling traffic is outpacing actual mobile data traffic by 30 to 50 percent, if not higher, 4G Americas says. Mobile network engineers began encountering that problem some years ago, when investigating cases of congestion on cell sites that seemed not to be experiencing especially-heavy demand. As it turned out, signaling operations were causing the congestion, not the bearer traffic. Since then, the problem has grown as more apps aim to deliver content and messages in real time.

A web-based instant messaging user may send a message but then wait a couple of seconds between messages. To preserve battery life, the smartphone moves into idle mode. When the user pushes another message seconds later, the device has to set up a signaling path again, 4G Americas notes in a new white paper.

For real-time Internet applications, the logical always-on connection between the server and client is required, resulting in frequent or periodic small heartbeat packets to be sent as a keep-alive message to maintain the connection.

“Push” services and “always on” apps add more load. All of that is in addition to the “bearer” traffic. Heavy users of apps illustrate what could happen to network demand as “early adopter” or “heavy user” behaviors become more mainstream. Today, heavy video or audio streamers consume about 2 Gbytes a day worth of video, or 1 Gbyte each day for audio streaming.

In other words, optimizing a mobile network for bearer traffic is one issue, while optimizing for signaling traffic is a different problem.

General computing these days revolves around content consumption and sharing, and heavy users of social networks can consume 7.5 Gbytes a month up to about 14 Gbytes a month. Cloud storage, for early adopters, now ranges from less than a gigabyte a month, up to about 5.5 Gbytes a month.

Leading users of gaming can consume gigabytes a day. The upshot is that total U.S. data traffic could grow 47 times over the next five years, unless wi-fi offload is available. If Wi-Fi offload is available, demand grows by “only” 24 times over the next five years.

The point, 4G Americas suggests, is that improvements to network, device platform, and application design can all help alleviate capacity issues, but there can be no lasting success without understanding end user behavior.

There is no question that end users are using more and more data every year. In 2011, 44 percent of mobile subscribers owned smartphones, which is more than double the market penetration of two years.

According to Nielsen, more than 50 percent of U.S. mobile phone users now use smart phones, in the first quarter of 2012.

Between 2010 and 2011, the numbers of smartphone subscribers engaged in various rich media activities other than mobile video have all grown by 45 percent or more. Numbers of subscribers performing game downloads and playing online games both increased more than 80 percent each in the same year, Nielsen also has reported.