Xue’s wireless networks research earns NSF Faculty Early Career Development award

An electrical engineer who is attempting to make wireless communications more reliable has received the National Science Foundation’s Faculty Early Career Development award. According to the National Science Foundation, these prestigious, five-year awards are given to exceptionally promising college and university junior faculty who are committed to the integration of research and education and are likely to become the academic leaders of the 21st century.

Yuan Xue – Dynamic management of wireless networks

Yuan Xue

Recent headlines such as “Traffic Jam In the Ether” and “A Squeeze On Smartphones” illustrate the basic problem that Yuan Xue, assistant professor of computer science and computer engineering, is addressing in her research: the need to develop a better way to manage wireless networks. Telecommunications companies have applied methods for utilizing their wireless resource that were developed for wired networks. That is one of the reasons for the prevalence of sluggish operation, dropped calls, weak signals and dead zones. The problem, known collectively as ‘mobile data congestion,’ is growing at an alarming rate as the number of smartphones and wireless tablets proliferate. Responding by “over-provisioning” – building more cell towers and lobbying the federal government to give them additional regions in the radio spectrum – is not likely to work for wireless networks in the long run, Xue said. “Wireless networks are dramatically different from wired networks. They are much more dynamic and multi-faceted because the devices move around, signal strength varies from moment to moment and the requirements of devices like smartphones vary dramatically depending on the specific applications that are running. The classical resource application framework did not foresee the complexity and impact of dynamics in wireless network performance.” The situation prompted Xue to develop a theoretical foundation for a dynamic-based approach for managing wireless networks by providing individual smartphones with the ability to vary their sending rate as the amount of traffic in their area varies in response to when the network is congested and allow smartphones to prioritize the communication requests that they receive from installed applications. Most smartphones use digital technology and they transmit information in short bursts called packets. Currently, the devices automatically connect with the strongest signal that they receive. In reality, the signal strength fluctuates widely. During periods of congestion, the available bandwidth to each phone also changes dramatically and rapidly. The packets that the phone sends when there is limited bandwidth are less likely to make it to the destination and so the phone has to retransmit them, adding to the congestion. On the other hand, there are times when the channel can handle more data than the phone is transmitting. So Xue would give smartphones the capability to monitor the available channel resource and vary their sending rate accordingly. This could reduce the amount of packet retransmission and increase the throughput substantially, she has calculated. In addition, the information about how much traffic base stations are experiencing would allow the phone to lock onto the best channel to use, not simply the channel with the strongest signal. Another topic Xue is exploring is the benefit of giving smartphones the ability to prioritize the transmission requests of its apps. Some apps, like phone calls or streaming video, need a nearly continuous stream of data. Others, like email or mapping programs aren’t nearly as demanding. Giving smartphones the ability to match these differing traffic demands against a varying wireless environment could improve their performance in many situations. Xue will be testing her theories with a remote medical care system that is undergoing a clinical trial at the Vanderbilt University Medical Center.