| Summary: | 碩士 === 國立臺灣科技大學 === 資訊工程系 === 97 === The IEEE 802.16e wireless metropolitan area network provides broadband wireless Internet access for mobile stations (MSs). Due to user mobility, how to save batteries to prolong the lifetime is an issue receiving much attention. Specified in the IEEE 802.16e standard, energy conservation is reached by allowing MSs to enter the sleep mode according to the three defined power saving classes for different traffic, for example, the power saving class of type I is suitable for the non-real-time traffic. However, non-real-time and real-time traffic may coexist in a MS. Therefore, other power saving classes should be simultaneously considered to reflect the real situation instead of considering the individual traffic type.
Aiming at this goal, we propose a predictive power saving mechanism for the power saving class of type I considering coexistence of the power saving class of type II. Through synchronizing power saving classes I and II, the unavailability interval is maximized by our proposed scheme. Predicting the inter-packet arrival time as well as the time interval between two occurrences of the power saving class of type II, the sleep interval of the power saving class of type I is suitably designed based on the predicted result when only the power saving class of type I is under consideration. Via simulations, we show that the proposed scheme outperforms the standard mechanism for the power saving class of type I in IEEE 802.16e in terms of packet delay and energy conservation. Even the standard mechanism works with the synchronization operations, our scheme still performs better than the combined mechanism.
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