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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/8379


    Title: 一種能量導向之IEEE 802.16e無線寬頻都會網路叢集合併排程機制;An Energy-Constrained Burst Mergence Scheme for IEEE 802.16e OFDMA System
    Authors: 謝光恩;Kuang-en Hsieh
    Contributors: 通訊工程研究所
    Keywords: IEEE 802.16e;WiMAX;WiMAX;IEEE 802.16e
    Date: 2009-06-22
    Issue Date: 2009-09-22 11:24:07 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 近幾年來,無線寬頻上網服務備受注目,也被視為下一代的無線網路基礎建設。無線寬頻上網除了要提供充裕的頻寬及高速移動的需求之外,也支援網路服務品質保證的相關機制,因此非常適合傳輸影像串流及語音傳輸等等的多媒體資料。WiMAX基地台為了服務大量的移動使用者,將無線網路資源切割成頻率及時間軸,並將移動使用者的資料叢集分配在不同的頻率及時間單位內,為了讓移動使用者能正確的接收及傳送資料,基地台產生上行及下行的排程單元,讓移動使用者能知道在哪個時間點及頻率可以接收屬於自己的資料。如果移動使用者的資料量較小,在同一個訊框裡放置許多個使用者的資料叢集會導致下行排程單元的資料量變大,整個無線網路系統的資源都浪費在傳送此控制訊息,造成系統的無謂的負擔。合併相同調變編碼的資料叢集可以減少相對個數的下行排程資訊單元,進而減低系統的負擔。但是使用者在接收較大的資料叢集時,需要花費更多的能量來解開自己部分的資料。如何在能量消耗及控制訊息的額外負擔上取得平衡是IEEE 802.16e重要的研究議題之一。 在此論文中,我們提出了一種能量導向之IEEE 802.16e無線寬頻都會網路叢集合併排程機制,根據移動使用者的剩餘電量等級來判斷合併資料叢集的個數,再加上不同的降階、叢集排序及再排程的策略來增加有效輸出及降低資料叢集的錯誤率。從實驗結果可看出我們所提出的方法及策略可以有效降低控制訊息及延長移動使用者的能量壽命。 In recent years, Broadband Wireless Access (BWA) systems have received the attentions as the next generation of wireless access infrastructure. It is considered that broadband multimedia data communications, such as video streaming and VoIP, can be realized by adopting the systems. The radio resource is partitioned as bursts in time and frequency domains and located to mobile stations (MS) in an exclusive manner. The base station (BS) functionally serves as a resource controller for traffic to/from the multiple associated MSs, and generates the proper downlink (DL) and uplink (UL) MAPs for active MSs based on service and traffic requirements. However, the DL-MAP construction scheme in IEEE 802.16e OFDMA system, which was designed for handling irregular traffic pattern of MS, often produces a large DL-MAP. If the size of burst is small, it will render a potential overhead from information element (IE) and limit the overall capacity. Merging a number of small bursts of same modulation coding scheme into a big burst can reduce the IE overhead; however, as the number of merged bursts increases, all the related MSs need cost more energy to decode and demodulate the big burst to retrieve their data. The energy consumption and control overhead are well known issues in the IEEE 802.16e system. It is desirable to have a solution to minimize the control overhead and reduce the energy consumption of the MSs. In this thesis, we propose an energy-constrained burst mergence (ECBM) scheme to merge bursts depending on MS’s energy level. Moreover, several strategies such as downgrading, burst re-sequence and re-schedule are proposed to enhance goodput and reduce the burst error probability. Simulation results show that our proposed ECBM scheme with different strategies not only minimize the number of control overhead, but also extend the life-time of MSs.
    Appears in Collections:[通訊工程研究所] 博碩士論文

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