College of Engineering News • Iowa State University

A new generation of recycling

Morris Chang
Morris Chang

Two researchers in electrical and computer engineering are starting a new trend in recycling, shifting from conserving materials like paper and aluminum cans to being more resourceful with digital space. The unique concept, called bandwidth recycling, is a response to the unprecedented changes taking place in the mobile industry.

Many of these changes are a result of the growing popularity of multimedia application running on smart phones and mobile applications, which places bandwidth availability in high demand. This trend creates logistical problems that Professor Morris Chang says his bandwidth recycling project can solve.

Chang and graduate student David Chuck have been working together to bring innovation to the mobile computing industry that will revamp the newly introduced 4G network. Their project, aimed at decreasing bandwidth waste, has made a promising emergence that can lead to further developments in the industry.

The launch of a new network

David Chuck
David Chuck

Mobile carriers have come to expect quicker technology from the industry, prompting service providers to shift from the existing 3G network to an enhanced 4G network. Verizon Wireless is currently the only provider that has upgraded to an unlimited data plan for the 4G network, but competing companies will soon follow. And while 4G is only available in more populated areas, such as New York, the conversion to the 4G network will continue to evolve, reaching users nationwide within one to two years.

The switch to 4G allows mobile carriers to use Internet Protocol, as well as experience a substantial increase in data speeds and smoother transitions between cell towers and networks when on the move.

“Another important feature of 4G is the Quality of Service (QoS) agreement, which ensures you will not have any delay on your video playback,” says Chuck. “To guarantee this service, a reservation based method is adopted in 4G technologies.”

The reservation method works by determining the quality level needed to playback a video. For example, if a user wanted to watch a video at 10 megabits per second (mb/s), the provider makes sure that the 10mb/s is available at all times. While a video may take up to 10mb/s at times, there will be times when it uses less space, creating bandwidth waste. Discovering this waste led Chang and Chuck to their research project.

Creating a simple, effective solution

To formulate possible solutions for bandwidth waste, Chuck and Chang first needed to assess the depth of the problem. “After some time we found that 30 percent of bandwidth was not being used, giving us a good range for improvement,” says Chuck.

cell towerWith a solid number to improve upon, Chuck and Chang began working on a variety of solutions. Chang says it took a considerable amount of time to investigate the problem, generate ideas, and carefully evaluate the potential benefits of different solutions with simulations and theoretical analyses.

Eventually, Chuck and Chang created a protocol with a simple, yet effective design by utilizing four scheduling algorithms to transfer the unused bandwidth to other users. The simplicity of their new protocol allows it to be added onto the existing protocol for the 4G network, so carriers won’t have to reconfigure their network.

Deciding how to allocate the recycled bandwidth is based on a scale of priorities. Tasks that don’t have a strict QOS would be considered low priority, which include web browsing and file downloads. Higher priority would be reserved for things such as Voice-Over-Internet Protocol (VOIP) and videos. “The use of recycled bandwidth cannot be expected on a regular basis, but if a high-priority task produces unused bandwidth, we can allow other users to recycle this bandwidth for low priority tasks,” explains Chuck.

The researchers developed a variety of protocols before finding the best option. The earliest version of their protocol resulted in an improvement of about 15 to 20 percent. After experimenting with scheduling algorithms, improvement percentages began to increase, and eventually the protocol reached a high of about 80 percent, averaging out at 40 percent improvement of network throughput.

Patiently awaiting a patent

With success in their research, Chang and Chuck are in the process of obtaining patents. They were approved for a professional patent through the Iowa State University Research Foundation, Inc. (ISURF), and the U.S. patent is currently pending. Once their project receives a patent from the U.S. Patent and Trademark Office, ISURF will begin selling a license for the technology to outside companies. According to Chuck, six months ago 17 companies were contacted by ISURF, showing a promising future for the project.

“We are hoping that as the 4G network becomes more populated, the value of our technology will become more obvious to cell phone carriers,” says Chang. For now, the researchers patiently wait, knowing that it will take time as university research tends to be a step ahead of industry and commercial application of research projects. Chang assures that this project will play an important role in 4G network in the next 5 to 10 years.

“We are happy to see that our project has been well-received within the research community and look forward to seeing the future acceptance by the industry,” says Chang. “As a researcher in engineering, there is nothing more rewarding than that.”

Continuing to advance mobile technology

Chuck and Chang say their work in mobile networks is far from finished. “As we move on, there are a lot of other issues that need to be looked into as the technology continues to evolve,” Chang says.

Future projects will include producing a “greener” network, something Chuck says he and Chang accidentally stumbled across in their bandwidth recycling project. “At the time, we weren’t concerned with saving energy, but we know that our protocol can also save some energy.”

Because unused bandwidth still needs to be verified, “dummy data,” or data with essentially no meaning, is sent, which in turn taps into the phone’s energy supply. With the new protocol, dummy data is not sent because the unused bandwidth is recycled, ultimately saving energy.

Chang explains that there will always be a need for innovations in the mobile computing industry because of the growing popularity and demand for services. “It is definitely an ongoing research direction, and we will continue to look into issues as they appear,” Chang says. “Right now we are enthused to move forward with research in multimedia applications such as VOIP and Internet TV as they become available on the 4G network.”