Faster more reliable wireless connections

Creating new global market opportunities.

cognitive radio

Every year, the US racks up over 2.2 trillion mobile talk minutes and sends more than 2.1 trillion text messages, all generating revenues of $164 billion and contributing over a quarter of a million jobs with the direct wireless carriers alone. By June 2011, nearly one-third of US households were wireless only, having no traditional telephone land line. There are more mobile-enabled talk or data devices in consumer hands than there are consumers.

And there is still more to come.

With major federal investments in wireless and new wireless communications spectrum opening up, researchers and entrepreneurs are positioning themselves to take advantage of a major wave of wireless development that is coming soon to your cell phone—and maybe even at your doorstep.

Dr. Rajarathnam ChandramouliDr. Rajarathnam Chandramouli of Stevens Institute of Technology exclaims: "This is a great time to be a wireless researcher." A Professor in the Department of Electrical and Computer Engineering and the co-founder (along with Prof. K.P. Suba Subbalakshmi) of a wireless technology startup, Dr. Chandramouli is a leading national expert in the next generation of "cognitive" communications that represent a major advance for businesses and wireless user experience.

At the center of the excitement is the National Wireless Initiative, an ambitious plan by the White House to bring 4G wireless connectivity to 98% of Americans. While wireless may seem ubiquitous to some of us, a US Commerce Department report claimed that in 2009 only 51% of rural homes had a broadband connection. Among the remaining 49% were many without high-speed options.

"The President's plan especially targets rural areas for broadband development," says Dr. Chandramouli, who in June participated in a White House roundtable discussion with US CTO Aneesh Chopra and other leaders in wireless development. "Broadband connectivity is an issue for rural areas because many ISPs are not willing to invest in infrastructure for areas with low population density. Wireless signals also have problems propagating through the mountainous regions that often go hand-in-hand with rural communities."

The consequences of restricted access to broadband for rural areas and small towns can be devastating, and has been compared to the barriers to electricity for rural areas in the early 20th century. For small towns, the promise of a more connected life in cities threatens to remove an entire generation of media-hungry youth from these communities. The outlook is worse for rural businesses, many of which are cut off from Web-based sales and marketing.

Much as the US government had to lay out the initial foundations—and cash—for expensive projects such as the transcontinental railroad in the mid-19th century and rural electrification in the 1930s and 1940s, the federal government is again taking strides to build infrastructure that enhances livelihoods in America's many nooks and crannies. This time, the target is not telephone or electrical wires, but wireless communications.

White House and FCC Open Doors to Innovation

As part of the national broadband plan, the White House and Federal Communications Commission (FCC) are preparing a deal to release 500 MHz of prime spectrum as unlicensed space specifically to kick-start innovation and applications for a nation's growing wireless appetite.

In 1985, the FCC took a similar step when it released underutilized scientific research radio frequencies for unlicensed use. Almost overnight, radical new technologies rolled out to exploit this spectrum. Cordless home phones, Bluetooth, and today's ubiquitous small-range wireless hotspots all rely on these open frequencies.

In 2011, "this spectrum is pretty saturated," says Chandramouli, but the FCC hopes that it can turn unlicensed T.V. white space bands into billions of dollars of commercial activity. "Google calls this 'Wi-Fi on steroids.' Microsoft calls it 'super wi-fi.' It is really prime spectrum with good propagation characteristics. Everyone is positioning themselves to take advantage of this as soon as it becomes available."

Unlike the tightly-regulated—and expensive—spectrum bought and sold for radio stations, television channels, and wireless carrier networks, unlicensed spectrum presents fewer barriers to entry. This means major industry players, small technology companies, and even university researchers like Chandramouli are on equal ground when it comes to capitalizing on this opportunity.

In fact, Dr. Chandramouli is among those positioning themselves to benefit from the FCC's spectrum release.

Cognitive Radio Breakthrough

Cognitive radio tesbedDr. Chandramouli develops complex technologies that drive a relatively straightforward concept known as "cognitive radio." Cognitive radio for dynamic spectrum access is the proposition that wireless communications devices should be able to intelligently scan the radio environment and identify the best frequencies over which to transmit and receive data. This offers radically different user interactions with wireless technologies.

"By implementing cognitive radio with open spectrum, you can have things like totally free talk and data plans that are ad-driven," claims Dr. Chandramouli. "It's not only a new technology, but it also allows new economic models."

To get to the business breakthrough, Dr. Chandramouli, Dr. Subbalakshmi and their students are putting together the technology from the ground up. Kai Hong is a PhD candidate working on a cognitive radio prototype in Dr. Chandramouli's lab at Stevens. He says that when he started his studies at Stevens, cognitive radio was still a blank slate.

"No cognitive radio test bed even existed," Kai recalls. "We had to create the software stack from scratch."

Kai HongTheir working prototype appears relatively simple. Four laptops, lined up side-by-side on a lab bench, tell the whole story. Two laptops are linked through a video chat, providing a live feed that helps researchers check that connection is never lost. A third laptop, which Kai calls the "Bad Guy," sends wireless signals that interfere with the frequency where the video chat is broadcasting. As referee, a fourth laptop provides a visual analysis of wireless activity between the other computers.

To demonstrate the prototype's effectiveness, Kai points to the graphical analysis to show that the video chat is occurring at a specific frequency. "The Bad Guy is going to provide interference at this frequency, and then the first laptop will switch to another frequency. Watch." He types in a few lines of code on the Bad Guy and then starts to wave his hand in front of the webcam on the first laptop. Without dropping a frame, Kai's image keeps waving on the third laptop while the cognitive radio software dynamically switches to an open frequency without losing the video chat connection.

"Most cognitive radio test beds have only changed the physical layer and the MAC layer," Kai reports, referring to the hardware and the lowest software layer of a network. "We go to the higher layers of the protocol stack also."

Public Safety Breakthrough

With the image of the multitudinous connections of a spider's web in his mind, Dr. Chandramouli refers to their cognitive radio prototype as SpiderRadio, which also services as the name of the technology product that will be marketed. In order to demonstrate cognitive radio's potential, Dr. Chandramouli goes to his most important future customers: public safety officials. The stringent requirements of emergency first responders and other public safety users provide the ultimate test of SpiderRadio's abilities.

"If you are just watching HD video on a mobile device, and your connection degrades for a minute, that is acceptable," Dr. Chandramouli says. "But for safety officials, not even one minute of poor connection is allowed, especially during emergencies."

It makes a tough proving ground for an experimental technology, but public safety is already poised to be a key market for early cognitive radio adopters. While dedicated communication channels prove robust in most everyday situations for public safety groups, the National Institute of Justice (NIJ) acknowledges holes in existing inter-operable first responder communications that it hopes to fill with cognitive radio enabled systems. In fact, NIJ supports the Stevens research work with funding and support so that communications problems such as happened in the wake of 9/11 will never happen again.

To minimize interference, first responders such as the fire department, police, and Coast Guard rely on dedicated communications frequencies. However, between departments or between towns, these frequencies can be unique. On most days, that is fine. But for responding to a major natural disaster or an attack like 9/11, when first responders from across the nation flooded New York City, these different organizations cannot change their frequencies to communicate collaboratively.

"When we realized that first responders could not talk to each other, we knew that was an important field where cognitive radio could provide a benefit. It allows us to rigorously test out fundamental research issues while also field testing SpiderRadio for some of our most important future users."

From his perspective in the lab, Kai also sees working with first responders as a catalyst for innovation. "Part of the challenge in building something for first responders is of course cost. High-end hardware for cognitive radios can cost in the tens of thousands of dollars, but they need something that costs in the hundreds."

To make SpiderRadio cost-effective, Kai and others have identified off-the-shelf hardware that can be re-engineered with their custom software stack to make it cognitive-radio-ready. However, these affordable options still have to perform one hundred percent of the time for emergency responders.

"For public safety especially, we have to push the envelope on developing a robust intelligence into the prototype," explains Dr. Chandramouli. "Cognitive radio has to be smart enough to let wireless devices learn from the past and make predictions about the future to make adjustments in advance of anticipated problems."

Future of Cognitive Radio

Although cognitive radio remains in the test bed, it is not a question of "if" but "when" this technology becomes synonymous with our wireless networks. A rudimentary cognitive radio is already built into all Wi-Fi devices, which are required to detect interference and react. Existing only at the device level, it is far from the ubiquitous dynamic spectrum access that will exist when cognitive radio is built into the wireless network stack.

Kai predicts that it will be another three to five years for the paradigm switch to occur. "After that, you can have embedded wireless experience in your everyday life, but it's only possible with cognitive radio."

New commercial development is expected to absolutely erupt with the coming release of unlicensed wireless spectrum. Everything from mobile phones to applications to network stacks will need to be retooled to efficiently capitalize on the spectrum's potential. "Every app will have cognitive radio capabilities," Chandramouli forecasts. "Software will be able to tell when there's not enough bandwidth, and tell the device to find a better frequency. Everything will have to change."

A few are even willing to put the effect in numbers. Microsoft has predicted cognitive radio alone to generate $1 billion a year for each of the next fifteen years. The White House is so optimistic about job creation that it fully expects the spectrum release to "lower the deficit."

While he admits to being an engineer, and not an economist, Dr. Chandramouli says that the government's claims are not fantasy. "Since the barriers to entry with unlicensed bands are so low, small businesses are really the ones set to take advantage of this opportunity." Federally-funded loans for technology entrepreneurs are anticipated to further drive job creation.

Kai's days may be spent quietly writing code on four laptops, but he is enthusiastic about being integral to the impact that cognitive radio is having. "As an engineer, I like to make new things that then give other people new jobs and new ways to do things," he says. "I want this to get out there to improve everyday life."

With the goal of 98% broadband connectively in sight, wireless pioneers like Kai and Dr. Chandramouli are not only providing better livelihoods for rural businesses and residents, but also fundamentally changing the way that people interact, share, and talk across the globe. As Chandramouli says, it is a great time to be a wireless researcher.