基於 IEEE802.16e 排程省電演算法

Abstract

在移動式網路由於電池壽命的限制，省電是一個很重要的 議題。為了適應不同的傳輸型態，各種不同的省電方法都被 提出來，然而很多報告都只考慮單一型態的傳輸型態，這篇 論文提供可以解決多種傳輸型態的排程方法。一個演算法叫 做近似省電演算法它處理了多種傳輸型態的聚合而且他也符 合規範的服務品質，不幸的是他不是一個最佳化的演算法， 所以我們為了求得最佳演算法而假設了一種特別的傳輸型態 來驗證近似省電演算法的正確性。為了要求得最佳化我們也 假設了無限的頻寬從而證明最少甦醒演算法的是一個最佳化 演算法同時為了要減少復甦跟睡眠模式的切換我們也提出了 一個演算法叫做最少切換演算法來達到這個目的。

The limitation on the battery lifetime has been a critical issue for the advancement of mobile computing. Different types of power-saving techniques have been proposed in various fields. In order to provide feasible energy conserving mechanism for the Mobile Subscriber Stations (MSSs), three power-saving types have been proposed for the IEEE 802.16e broadband wireless networks. However,these power-saving types are primarily targeting for the cases with a single connection between the Base Station (BS) and the MSS. With the existence of multiple connections, the power efficiency obtained by adopting the conventional scheduling algorithm can be severely degraded. In this work, a Heuristic Power Saving Scheme (HPSS) scheduling algorithm is proposed to consider the aggregated effect from the multiple connections to the power efficiency. Moreover, the Quality-of-Service (QoS) constraints from downlink traffic are employed in the design of the HPSS algorithm in order to facilitate the corresponding MSS to fulfill its QoS requirements. Unfortunate, even though the performance of the HPSS is efficient, it is not optimal. Since of this reason, we simplify the problem by special traffic type of the CID and an optimal algorithm called Maximal Power-Conserving (MPC) is proposed. It is designed to optimal the energy efficiency based on the pre-specified Quality-of-Service requirements. In order to optimize the power saving efficiency, It is needed to assumed the resource of bandwidth is unlimited. An optimal algorithm called Least Awake Frame Scheme (LAFS) is proposed. The design concept of LAFS focus on scheduling the deadline of the data burst. Moreover, an algorithm called Least Switching Times Scheme (LSTS) is proposed. the LSTS algorithm reserve the advantage of the LAFS, It is design for optimal the MSS switching times between listen interval and sleep interval. The minimal awake frames and minimal switching times of the MSS will also be proved in this paper. Numerical results show that the proposed HPSS scheduling algorithm outperforms the conventional 802.16e power-saving mechanism, the Periodic On-Off Scheme (PS) and the Aperiodic On-Off Scheme (AS).