通訊所演講- Dr. Yin Sun (the Ohio State University ) - Life-Add: A Redesign of WiFi for Smartphones with Battery Life, Throughput and Fairness Improvements
ABSTRACT:
Smartphones has become extremely prevalent around the world. By May 2013, 56% of all American adults are smartphone users. One serious problem of smartphones is their short battery life, due to the high energy consumption components such as WiFi, GPS, Screen, etc.
In this talk, we will examine the current MAC designs in IEEE 802.11 WiFi standards, and identify the key issues that affect the battery life and throughput performances of smartphones during WiFi usage. We will introduce Life-Add, which utilizes a sleep-wake mechanism to reduce the energy consumption and resolve the channel contention among coexisting devices. In this mechanism, a WiFi device turns off its radio to save energy when the channel is sensed to be busy, and sleeps for a random time period before sensing the channel again. By modeling the WiFi transmission behaviors as a renewal process, we find a simple way to optimize the sleep backoff time parameters. This is in contrast to IEEE 802.11, where parameter optimization is very difficult due to the complicated 2-D Markov chain model. It is proven that Life-Add achieves near-optimal proportional-fair utility performance for single access point (AP) scenarios. Moreover, Life-Add alleviates the near-far effect and hidden terminal problem in general multiple AP scenarios.
Our ns-3 simulations show that Life-Add improves the average battery life of the smartphones by 49%, improves the average throughput of the smartphones by 36% under WiFi usage. The fairness performance among coexisting WiFi devices is also significantly enhanced. Our simulations further show that Life-Add can coexist harmoniously with IEEE 802.11: if some smartphones and APs upgrade from IEEE 802.11 to Life-Add, the throughput performance improves for both the smartphones switching to Life-Add and those sticking to IEEE 802.11, and the battery life performance is enhanced only for the smartphones switching to Life-Add.
BIOGRAPHY:
Yin Sun received his Ph.D. and B.S. degrees from Tsinghua University in 2011 and 2006, respectively, both in Electrical Engineering. He received Excellent Doctoral Dissertation Award of Tsinghua University (25 winners in 1566 graduated PhDs), Excellent Bachelor's Thesis Award of Tsinghua University and many scholarships.
He was a visiting student at National Tsing Hua University, Taiwan from Dec. 2010 to Feb. 2011. Since August 2011, He has been working with Prof. Ness B. Shroff and Prof. C. Emre Koksal at the Ohio State University as a postdoctoral researcher. Dr. Sun's research interests include both theoretical analysis and practical designs of wireless communication networks. His paper has received the best student paper award (from all papers whose first author is a student) at IEEE WiOpt 2013.
Smartphones has become extremely prevalent around the world. By May 2013, 56% of all American adults are smartphone users. One serious problem of smartphones is their short battery life, due to the high energy consumption components such as WiFi, GPS, Screen, etc.
In this talk, we will examine the current MAC designs in IEEE 802.11 WiFi standards, and identify the key issues that affect the battery life and throughput performances of smartphones during WiFi usage. We will introduce Life-Add, which utilizes a sleep-wake mechanism to reduce the energy consumption and resolve the channel contention among coexisting devices. In this mechanism, a WiFi device turns off its radio to save energy when the channel is sensed to be busy, and sleeps for a random time period before sensing the channel again. By modeling the WiFi transmission behaviors as a renewal process, we find a simple way to optimize the sleep backoff time parameters. This is in contrast to IEEE 802.11, where parameter optimization is very difficult due to the complicated 2-D Markov chain model. It is proven that Life-Add achieves near-optimal proportional-fair utility performance for single access point (AP) scenarios. Moreover, Life-Add alleviates the near-far effect and hidden terminal problem in general multiple AP scenarios.
Our ns-3 simulations show that Life-Add improves the average battery life of the smartphones by 49%, improves the average throughput of the smartphones by 36% under WiFi usage. The fairness performance among coexisting WiFi devices is also significantly enhanced. Our simulations further show that Life-Add can coexist harmoniously with IEEE 802.11: if some smartphones and APs upgrade from IEEE 802.11 to Life-Add, the throughput performance improves for both the smartphones switching to Life-Add and those sticking to IEEE 802.11, and the battery life performance is enhanced only for the smartphones switching to Life-Add.
BIOGRAPHY:
Yin Sun received his Ph.D. and B.S. degrees from Tsinghua University in 2011 and 2006, respectively, both in Electrical Engineering. He received Excellent Doctoral Dissertation Award of Tsinghua University (25 winners in 1566 graduated PhDs), Excellent Bachelor's Thesis Award of Tsinghua University and many scholarships.
He was a visiting student at National Tsing Hua University, Taiwan from Dec. 2010 to Feb. 2011. Since August 2011, He has been working with Prof. Ness B. Shroff and Prof. C. Emre Koksal at the Ohio State University as a postdoctoral researcher. Dr. Sun's research interests include both theoretical analysis and practical designs of wireless communication networks. His paper has received the best student paper award (from all papers whose first author is a student) at IEEE WiOpt 2013.