January 30, 2012
Dr. Kyunghan Lee, senior research associate, and Dr. Mladen Vouk, professor and department head in the NC State Computer Science Department, have received three awards totaling $225,000 from Samsung Electronics, Co., Ltd. to support their research proposals on smartphone efficiency and localization techniques.
Proposal #1 ($75,000): “Improving Energy Efficiency Through Elimination of Unnecessary WiFi Scans Using Cellular Signal Information.”
Abstract - In this project, a system providing intelligence to WiFi AP scan operations will be studied and developed for Android-operated smart devices, to reduce energy consumption in using WiFi chipsets. We ultimately aim at eliminating WiFi scans when users are mainly moving around their living boundaries by predicting which WiFi AP to connect without scanning. The prediction will be performed based on matching algorithms that find the similarity between a short term observation of cellular signal information measured in a smart device and a database of WiFi APs containing cellular base station IDs and their signal strength information per WiFi AP accumulated whenever the device is connected to a specific WiFi AP. Given our small scale measurement of energy consumption showing that WiFi scan operations drain about 10~15% of battery capacity of smartphones in their daily usages, our proposed algorithm is expected to be able to save substantial amount of energy in smart devices.
Proposal #2 ($75,000): “Improving Energy and Data Communication Efficiencies of Smartphones Through a Receiver-based TCP Control Mechanism for Cellular Networks.”
Abstract - As smart devices like smartphones and tablet computers become prevalent, TCP performance over cellular networks is of growing importance. However, various measurement studies reveal that TCP suffers from excessively long delay as well as throughput degradation in cellular networks. In this project we will conduct extensive experiments over the 3G/4G networks of various cellular network carriers and investigate several under-developed issues: the current 3G/4G networks are over-buffered (termed as bufferbloat) and the excessive buffers void TCP congestion control who relies on packet loss to detect network congestion. Since all the overshot packets are absorbed by the buffers, no packet is lost and TCP will keep increasing its congestion window even if it is already much larger than the underlying bandwidth-delay product. To mitigate such problems, smartphones set the maximum receive buffer size to a relatively small value. Although this simple provisional scheme alleviates the aforementioned problem, it is losing performance in a number of scenarios due to its static nature. Through this project, we aim at proposing an adaptive receive window adjustment algorithm that requires changes only in receiver-side and implement it in Android phones and tablets.
These awards will run from December 1, 2011 through November 30, 2012.
Proposal #3 ($75,000): “Investigation of a Novel Indoor Localization (Navigation) Technique for Smartphones.”
Abstract - In this project, we aim at developing a new indoor localization technique relying on low-frequency radio that can penetrate indoor obstacles (or detour obstacles by diffraction in the shortest path) by its long wave characteristics. The smartphone running this system would be able to identify its position by measuring straight-line distances from a few radio transmission towers deployed in a city scale (or in a district scale). Straight-line distances that have not been affected by indoor obstacles would be able to provide a three-dimensional position including floor information and position information in the floor (e.g., store information in a shopping complex).
This award will run from January 2, 2012 through December 31, 2012.