Mobile data traffic has almost doubled annually over the last few years and continues to grow unabated, prompting the industry to take drastic measures. While demand projections vary, the goal of “1,000x growth” captures the sentiment. Does 1,000x sound like a tough challenge? Yes. Is it possible to support such growth? Yes, especially when you examine the technological advancements in the pipeline and put your faith in the brain trust working on future enhancements. This challenge will test a few limits of technology (literally — think Shannon’s limit) along with our belief that the human mind can use innovation to overcome big challenges.
Whenever people say “1,000 times” more, it’s usually just hyperbole. But when it comes to mobile broadband traffic growth, 1,000x is more reality than embellishment. A typical mobile device owner might ask, “Why should I worry?” Answer: overloaded networks result in lower speeds, stuttering videos, unresponsive games and other issues leading to unsatisfactory mobile experiences.
What’s needed? You start by improving existing networks—continuing to evolve 3G, 4G and Wi-Fi. But a challenge of this magnitude needs more resources and, more importantly, radically new ways of acquiring, deploying, managing and optimizing these resources.
Small is the new big
Small cells (miniature base stations) are already popular among mobile operators. However, we need more of them, everywhere — indoors and outdoors, in residences and in enterprises. And we need all the familiar flavors — 3G, 4G, Wi-Fi (often all integrated in a single box) — in all the different forms, including user installed femtos, operator installed picos, metros, relays, remote radio heads, distributed antenna systems, etc.
Deploying this heterogeneous mix of cells (aka HetNets) is just part of the story. Small cells, deployed closely together, interfere with each other and with the larger macro network. To mitigate interference, advanced techniques must be employed, which substantially increases overall network capacity — more so than merely adding small cells. Some of these techniques are already developed and the industry is focused on further enhancing them and developing more to make extremely dense deployments of small cells more robust. Research shows that overall network capacity scales with the density of small cells, validating that reaching 1,000x capacity is more a question of when and how rather than if.
With so many variables involved in deploying small cells, there are numerous combinations of business cases, deployment models and market introduction strategies to choose from.
One promising example is the “Neighborhood Small cells” model — a network of extremely low-cost, plug-and-play, open, indoor small cells. It provides extremely high indoor capacity as well as good outdoor coverage and capacity in the immediate “neighborhood.” This model is cost effective because consumers deploy the small cells and provide the backhaul, saving operators time and money. Studies show capacity increases of up to 500x with a mere 9 percent penetration of households and up to 1,000x with 20 percent penetration, when combined with 10x more spectrum.
Spectrum, precious spectrum
Spectrum is one resource that operators always want more of. Unfortunately, there’s just not enough to go around. One opportunity for new 3G/4G spectrum is in higher bands such as 3.5 GHz. Because of their smaller coverage, these bands were previously underutilized, but that limitation actually makes them attractive for small cells, since smaller coverage reduces interference.
In cases where clearing spectrum is not possible, the industry is proposing a new regime called Authorized Shared Access (ASA), which can potentially unlock hundreds of MHz of spectrum for 3G/4G services.
Because of the nature of their operations, many spectrum holders, such as government users, do not use the entire block of allocated spectrum in all of their licensed regions on a 24×7 basis. For example, U.S. naval radar uses spectrum only on the coastline, although the Navy is allocated that spectrum countrywide. In such cases, ASA allows incumbent spectrum holders and 3G/4G operators to share this underutilized spectrum (based on location or time) on mutually beneficial terms, without interfering with each other.
Of course, we also need more unlicensed spectrum for Wi-Fi, especially, for the next generation which leverages wider bandwidths to offer extremely high data rates. Recently, operators have overwhelmingly embraced Wi-Fi, because it allows them to opportunistically offload traffic from strained 3G/4G networks.
More than the sum of its parts
With networks and mobile devices becoming so complex, and with the apps and services market showing explosive growth, it’s essential that the individual parts of the network are optimized and work in harmony to offer higher overall capacity and better user experiences.
A good example is the scenario where a device is within the coverage range of 3G, 4G, Wi-Fi and others, served by both macro network and small cells. Devices should have the intelligence to select the most appropriate link(s) among all these, based on the signal level, possible data speed, network congestion, and the actual application or service it is using, etc., so that the user gets the best experience, while maximizing overall system performance.
There are also many innovative technologies that exist today, or are in development, that can increase the capacity for specific applications. For example, LTE Broadcast (eMBMS) allows operators to efficiently offer multimedia services in a broadcast mode when a high concentration of users accesses the same content simultaneously. LTE Direct is another technology that allows devices to efficiently and directly connect to each other (for peer-to-peer applications) without having to route the connection through the macro network.
A tailor-made strategy
Given the diverse nature of the mobile business, obviously there is no one-size-fits-all solution. Each operator must tailor a strategy that suits its needs. However, the bottom line is, no matter how extraordinary the 1,000x challenge appears, it is indeed possible to find solutions that will successfully meet the growing demand for mobile data.