The Next-Generation Cellular Network Takes Shape

Ron Wilson, Altera

The global network supporting mobile devices is facing profound challenges to its architecture and to its underlying technology. Driven by cell phones’ own spectacular success, the number of mobile client devices and their individual appetites for bandwidth keep growing. But the bandwidth allocated to the mobile carriers is not increasing at anything approaching the same rate. And the efficiency with which the network can exploit a given channel is also leveling off. The next generation of the radio access network must deal with these challenges, and therein lies a tale.

The Insatiable Hunger

It is news to no one that demand for mobile bandwidth is growing. Less obvious is that the growth is compound: three factors multiply together to product the demand surge. One factor is the familiar build-out of infrastructure and resulting growth in client base. Second is a shift in the nature of the devices. Third is a change in the structure of applications.

Client growth is probably the smallest of the three factors. Penetration of mobile devices into developed-country markets is near saturation. Many affluent individuals use more than one mobile device, often simultaneously. There are still many potential users in the rural world, but their initial concern is access, not bandwidth.

If the absolute number of cellular devices might begin to level off, the types of devices users select is shifting up-market. Intel Mobile & Communications Group vice president and general manager Hermann Eul, at a recent DesignCon keynote, pointed out that the replacement time for handsets is dropping toward a new device every 18 months. Smart phones are the items of choice. And even cost-sensitive users want to upgrade. “From this year on, over half the expenditure in the smart phone market will be in the value, entry, and ultra-low-cost segments,” Eul said.

As people get smarter phones, they use them more. “We are seeing an average of about 26 hours of active use per week,” Eul stated. The combination of more data-hungry phones and more hours of use multiplies out to more data traffic.

During those 26 hours, the user is generally running apps that are far more demanding of bandwidth than they used to be. “Apps today are as complex as the full computer programs of five to ten years ago,” Eul observed. Interestingly, those apps are not just pushing their CPUs harder, but they are demanding more bandwidth as well, as they suck data from—and sometimes share the computing load with—the cloud. Even seemingly innocuous apps like voice command entry and map navigation can quietly move significant amounts of data over the air as they call on remote computing and storage resources.

More users, more smart phones, more demanding apps: the product is rapidly increasing bandwidth demands. Some analysts predict a sustained cumulative annual growth rate of 66% in wireless traffic until 2017. By that time the amount of data transferred will reach a rather inconceivable 11 exabytes per month. What is a carrier to do?

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