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    題名: Energy-efficient and channel-aware power saving and rate adaptation MAC protocols in wireless ad hoc networks
    其他題名: 無線隨建即連網路下有效電源使用與頻道狀態感知為考量之省電與傳輸速率調適媒體存取控制協定
    作者: 周建閔;Chou, Chien-min
    貢獻者: 淡江大學資訊工程學系博士班
    石貴平;Shih, Kuei-ping
    關鍵詞: 無線隨建即連網路;多速率傳輸;電源節約;傳輸速率調適;有效率電源使用;Wireless ad hoc networks;multi-rate;Power saving;Rate adaptation;energy efficiency
    日期: 2010
    上傳時間: 2010-09-23 17:35:03 (UTC+8)
    摘要: 因無線網路本身的特性影響,在無線網路的環境中,傳輸資料的可靠性,遠遠不如有線網路,因此傳輸資料的成功率,也因此較有線網路來的低。背景雜訊、來自其他節點的干擾、訊號衰減、都卜勒效應等,皆會影響無線網路中,資料傳輸的成功與否。因此一個適當設計且能感知到無線網路環境中干擾的媒體存取控制協定,是有其必要性的。除此之外,在無線網路的環境中,有限的資源嚴重的限制了網路的使用(例如頻寬、裝置的電池電力等),高網路流量與高密度的網路節點,皆易導致傳輸資料的碰撞,並消耗多餘的頻寬與電源。本論文首先於無線隨建即連網路中,提出一個有效電源使用與頻道狀態感知為考量之省電媒體存取控制協定,名為PEM。在PEM中,節點可使用傳輸電量控制,除了避免傳輸碰撞並節省電源消耗,並可增進空間再利用率。基於MIS概念,一個啟發式的演算法亦在PEM中所提出,此演算法可讓盡可能多的節點,於空間中同時傳輸資料,因此PEM除了讓節點節省更多的電源,也將有較好的效能與電源使用效率。本論文之後提出一個在無線隨建即連網路下有效電源使用與頻道狀態感知為考量之傳輸速率調適媒體存取控制協定,名為FaRM,FaRM依據即時的頻道品質,動態且即時的決定傳輸速率與對傳輸封包進行切割。模擬的結果顯示,本論文所提出的兩個協定,與先有的協定相比較,除了可大幅增進網路效能、亦可大量減少電源消耗與傳輸延遲。
    Wireless medium is much unreliable compared with the wired medium due to its open nature. The successful transmission rate in wireless environment is much lower than that in wired environments. Background noise, interference from other stations, signal attenuation, signal fading, and Doppler effect will have great impact on the success of a wireless transmission. Consequently, a well designed MAC protocol in wireless environments needs to be aware of the interference in wireless environments. Besides, scarce resources of wireless medium (e.g., bandwidth, battery power, and so on) significantly restrict the progress of wireless networks. Heavy traffic load and high station density are most likely to incur collisions, and further consume bandwidth and energy. The dissertation initially presents an energy-efficient and channel-aware power saving MAC protocol in Wireless Ad Hoc Networks, namely PEM. In PEM, stations are capable of avoiding collisions and saving energy. Besides, PEM takes advantage of power control technique to reduce the interferences among transmission pairs and increase the spatial reuse of wireless networks. Based on the concept of Maximum Independent Set (MIS), a novel heuristic scheme with the aid of interference relationship is also presented in PEM to provide as many simultaneous transmission pairs as possible. Afterward, the dissertation proposes an energy-efficient and channel-aware rate adaptation MAC protocol in Wireless Ad Hoc Networks, namely FaRM. It is well-knows that the channel quality varies with time in wireless environments. Transmission errors may occur due to the variation of channel quality. Accordingly, stations in FaRM can dynamically detect the current SNR to estimate the channel quality through the control frame exchanges. Furthermore, a Finite State Markov Chain (FSMC) is adopted to predict the variation of the channel condition. According to the results generated from FSMC, FaRM enables a station to select an appropriate transmission rate as well as an acceptable fragment length dynamically to transmit in order to both increase the reliability and shorten the channel access time of the transmission. Simulation results shows that the proposed two MAC protocols can utilize the energy well. Besides, the proposed two MAC protocols outperform the existed related works.
    顯示於類別:[資訊工程學系暨研究所] 學位論文

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