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Title:LISP: A Link-Indexed Statistical Traffic Prediction Approach to Improving IEEE 802.11 PSM
Author(s):Hu, Chunyu; Hou, Jennifer C.
Subject(s):wireless networks
wireless ad hoc networks
Abstract:Power management is an important technique to prolong the lifetime of battery-powered wireless ad hoc networks. The fact that the energy consumed in the idle state dominates the total power consumed on wireless network interfaces motivates use of protocols that put the radio into the sleep mode in the lack of communications activities. IEEE 802.11 PSM is a representative of such protocols. However, the performance of IEEE 802.11 is significantly degraded under PSM because of the wake-up latency thus introduced. In this paper, we propose a novel and complementary mechanism, named by Link-Indexed Statistical traffic Predictor (LISP) to improve IEEE 802.11 PSM. Essentially LISP employs a simple, light-weight traffic prediction method and enables each node to seek the inherent correlation between ATIM ACKs and incoming trafffic. Once such a correlation is identified, a node en route stays awake in the beacon interval (BI) in which a packet is anticipated to arrive, thus bridging a "freeway" for the packet to rapidly traverse the route. In this manner, a packet can travel from the source to the destination within one BI ideally. Meanwhile, the number of duty cycles is minimized and more energy is conserved. LISP differs from previous work [12], [2], [14] in that we do not trade energy for better end-to-end performance at light to moderate traffic loads, i.e., we reduce the end-to-end delay without consuming more power. Instead more energy is saved because of the reduction in duty cycles. We conduct analytical and simulation studies. The impact of various factors, including traffic load, number of hops, ATIM window size and packet sizes are investigated using a tandem topology. In a general scenario simulated, LISP demonstrates the improvement over PSM in the end-to-end delay by 65-75%, and an increasement of the energy efficiency over IEEE 802.11 with and without PSM by 6% and 178%, respectively.
Issue Date:2003-12
Genre:Technical Report
Rights Information:You are granted permission for the non-commercial reproduction, distribution, display, and performance of this technical report in any format, BUT this permission is only for a period of 45 (forty-five) days from the most recent time that you verified that this technical report is still available from the University of Illinois at Urbana-Champaign Computer Science Department under terms that include this permission. All other rights are reserved by the author(s).
Date Available in IDEALS:2009-04-20

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