Enhancing IEEE 802.11 Energy Efficiency for Continuous Media Applications

This paper proposes the Optimized Power save Algorithm for continuous Media Applications (OPAMA) to improve end-user device energy efficiency. OPAMA enhances the standard legacy Power Save Mode (PSM) of IEEE 802.11 by taking into consideration application specific requirements combined with data aggregation techniques. By establishing a balanced cost/benefit tradeoff between performance and energy consumption, OPAMA is able to improve energy efficiency, while keeping the end-user experience at a desired level. OPAMA was assessed in the OMNeT++ simulator using real traces of variable bitrate video streaming applications. The results showed the capability to enhance energy efficiency, achieving savings up to 44% when compared with the IEEE 802.11 legacy PSM.

An IEEE 802.11 energy efficient mechanism for continuous media applications

The widespread deployment of wireless mobile communications enables an almost permanent usage of portable devices, which imposes high demands on the battery of these devices. Indeed, battery lifetime is becoming one the most critical factors on the end-users satisfaction when using wireless communications. In this work, the optimized power save algorithm for continuous media applications (OPAMA) is proposed, aiming at enhancing the energy efficiency on end-users devices. By combining the application specific requirements with data aggregation techniques, {OPAMA} improves the standard {IEEE} 802.11 legacy Power Save Mode (PSM) performance. The algorithm uses the feedback on the end-user expected quality to establish a proper tradeoff between energy consumption and application performance. {OPAMA} was assessed in the OMNeT++ simulator, using real traces of variable bitrate video streaming applications, and in a real testbed employing a novel methodology intended to perform an accurate evaluation concerning video Quality of Experience (QoE) perceived by the end-users. The results revealed the {OPAMA} capability to enhance energy efficiency without degrading the end-user observed QoE, achieving savings up to 44 when compared with the {IEEE} 802.11 legacy PSM.

Entwickelung der jüdischen Wohlthätigkeits-Einrichtungen : Fürsorge u. Selbsthilfe ; Referat in d. Delegirten-Versammlung des Verbandes f. jüd. Wohlthätigkeitspflege am 21. Febr. 1901

von Wilhelm Neumann

Zur Geschichte der Juden in Einbeck : Vortrag gehalten am 4. Dezember 1901 im Verein für Geschichte und Altertümer der Stadt Einbeck und Umgegend

von Wilhelm Feise

De finantieele positie van den israel. godsdienstonderwijzer : Rede uitgespr. op de 8e algemeene vergadering van "Achawah" ... te Hilversum, op Dinsdag 14 Menachem 5656 (30 Juli 1901)

door A. van Creveld

"Was hat die jüdische Gemeinde Königsbergs König Friedrich I. im besondern zu verdanken?" : Vortrag, gehalten am 15. Januar 1901 im Verein für jüd. Geschichte u. Litteratur zu Königsberg i. Pr.

von Ed. Birnbaum

History of the ancient synagogue of the Spanish and Portuguese jews : the Cathedral Synagogue of the jews in England situate in Bevis Marks ; a memorial vol. wirtten spec. to celebrate the 200. anniversary of its inaug., 1701 - 1901

by Moses Gaster

A Passive Source Localization System for IEEE 802.15.4 Signal

In this work, we provide a passive location monitoring system for IEEE 802.15.4 signal emitters. The system adopts software defined radio techniques to passively overhear IEEE 802.15.4 packets and to extract power information from baseband signals. In our system, we provide a new model based on the nonlinear regression for ranging. After obtaining distance information, a Weighted Centroid (WC) algorithm is adopted to locate users. In WC, each weight is inversely proportional to the nth power of propagation distance, and the degree n is obtained from some initial measurements. We evaluate our system in a 16m-18m area with complex indoor propagation conditions. We are able to achieve a median error of 2:1m with only 4 anchor nodes.