An Inside-Out Approach To Cellular Network Optimization

Cellular radio spectrum is like real estate. Build as we might, we are not getting any more of it. The task in front of the cellular carriers and their partners over the next couple of years is to optimize the spectrum we have to ensure that as many people as possible stay connected as smart mobile devices proliferate. Chipmaker Qualcomm has a theory that will help optimize our networks, and it is not quite what you might think.

Today It's Outside-In

The fundamentals of cellular data are built on an “outside-in” approach. That means that the cellular towers and base stations are built outside (often in environment-protected environments) and data flows to users inside buildings (or wherever they happen to be. The coverage these towers provide can be improved through technological upgrades, increased spectrum availability and, well, just building more towers. 

Eventually, though, the towers we have are not going to be enough to cover everybody that wants to be covered, doing everything they want to do with their smartphones. We want to be able to listen to music, watch videos, connect via emails and social networks, make phone calls. If the towers cannot match the demand, the entire mobile industry basically falls over like a house of cards. 

That could happen sooner than we think. Data use has been basically doubling every year for the last several years. More people have smartphones than ever before and they are adding tablets, like iPads, to their data plans. 

Qualcomm CTO Matt Grob shows an example of network interference between two cell towers at EmTech in Boston Qualcomm CTO Matt Grob shows an example of network interference between two cell towers at EmTech in Boston

According to Matt Grob, the executive vice president and chief technology officer of Qualcomm, there are three primary challenges to optimizing spectrum and coverage from the traditional “outside-in” macro-cell approach:

  1. Interference management - when a cellphone is on the edge of the coverage area of two different towers and does not know which signal it should use.
  2. Backhaul - the obligation to carry data packets back and forth from the sub-network (the tower and its coverage area) to the global network.
  3. Network economics - who pays for the new infrastructure. 

The Future Is Inside-Out

To optimize the networks for the coming demands, a new approach is needed. Grob promotes an interesting alternative to the simple process of just building more towers (which becomes economically and technoligically infeasible past a certain point). He calls it the “inside-out” approach and it only takes a small percentage of people to greatly optimize cellular network density.

The general idea is this: consumers and businesses invest in relatively cheap indoor base stations known as femtocells. Between those femtocells, the network coverage greatly increases as interference and backhaul are improved by increased coverage and stronger signals. The infrastructure is supplemented by users, each for a small percentage of what it would have taken to build an entirely new tower for the entire neighborhood. Get enough neighbors together and network optimization increases by orders of magnitude. 

“As coverage starts to build up [from indoor personal femtocells], you start to see fairly good coverage outdoors,” Grob said at a presentation at the MIT Technology Review EmTech Conference in Boston on Wednesday.

A Densification Augmentation

Grob notes that these inside-out femtocells are not a standalone solution to network optimization. 

“We still rely on the macro network. The network I am talking about here is a densification technique, it is not capable of standing alone. We are not going to dot the countryside with these things. The macro base station is still there to provide the ubiquitous-level coverage, but this is a densification method used to increase the capacity,” Grob said. 

“It can serve as a powerful way to augment and densify an existing cellular network,” Grob said. “If one in eleven [people] deploy small cells, with 10-times more spectrum that we will get from auctions, we’ll get from shared access and unlicensed, all together, that alone with gives us 500-times improvement.”

Private Tech For The Common Good?

Across the world, we already see examples of how small base stations can improve the quality of coverage for a community. In India, local villages employ femtocells to boost the weaker signals in their areas. In countries with bigger, more developed cellular infrastructures, the goal is not just to provide coverage, but to make the coverage we have better. 

The trick will be to convince people to use the femtocells in ways that benefit other people. Providing femtocells in your home or business for the purpose of boosting your own signal is fine, but most of those are “closed” networks and they work only for the person that has deployed them. Yet providing personal base stations in urban environments for the common good could ensure that the quality of service - and quality of life - that we have come to expect our smartphones and tablets to deliver continues uninterrupted into the future.