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標題: | 藉由調整傳輸能量與傳輸速率以改善IEEE 802.11隨意網路之吞吐量 Improving Throughputs of IEEE 802.11 Ad Hoc Networks by Transmission Power/Rate Control |
作者: | Han-Chiuan Luo 羅漢全 |
指導教授: | 陳健輝 |
共同指導教授: | 吳曉光 |
關鍵字: | 隨意網路,IEEE 802.11,吞吐量,傳輸能量?速率控制方案,空間再利用,時空資源,非定頻道(fading channel), Ad hoc network,IEEE 802.11,throughput,power/rate control scheme,spatial reuse,space-time resource,fading channel, |
出版年 : | 2011 |
學位: | 博士 |
摘要: | 近十年以來,無線隨意網路受到相當多的矚目,因為它們不必有基礎設施就可以為不同的目的服務,如移動隨意網路,無線網狀網路,無線感測網路,或車輛隨意網路。時下無線隨意網路最廣泛採用的媒體接取控制(MAC)協議是 IEEE 802.11 標準分散式協調功能(DCF)。在 IEEE 802.11 隨意網路上,各種渴求頻寬的應用,帶來不斷增長的需求,導致提高網路吞吐量變得越來越重要。
在本論文中,我們著重在以下四個問題,它們是藉由調整傳輸能量與傳輸速率以改善 IEEE 802.11 隨意網路吞吐量的主要挑戰。 (P1) 一個傳輸能量控制(TPC)方案,用以提高 IEEE 802.11 隨意網路之吞吐量,該網路配備單個穩定頻道與單個傳輸速率。 (P2) 一個傳輸能量�速率控制(TPRC)方案,用以提高 IEEE 802.11 隨意網路之吞吐量,該網路配備單個穩定頻道與多個傳輸速率。 (P3) 一個TPC方案,用以提高 IEEE 802.11 隨意網路之吞吐量,該網路配備單個非定頻道與單個傳輸速率。 (P4) 一個TPRC方案,用以提高 IEEE 802.11 隨意網路之吞吐量,該網路配備單個非定頻道與多個傳輸速率。 針對(P1)問題,藉由最大限度地減小禁制區(ceased area),一個新的TPC方案被提出,用以增強 IEEE 802.11 隨意網路的空間再利用。禁制區對應於一對發射器和接收器,在此禁制區內的所有其他節點應該保持沉默,才能讓此對發射器和接收器之間可靠地傳收封包。 針對(P2)問題,一個新的TPRC方案被提出,其設計原則是基於時空資源的有效利用。因此,一項新的度量,名為STPB被引入,它代表了每位元所消耗的時空資源。藉由調整傳輸能量與傳輸速率,該方案可以最大限度地減小STPB。 針對(P3)問題,一個新的TPC方案被提出,該方案是以(P1)問題所提的方案為基礎,再根據非定的規模(scale of fading)來調整傳輸能量。針對(P4)問題,一個新的TPRC方案被提出,該方案是以(P2)問題所提的方案為基礎,再根據非定的規模、移動平均頻道增益,分別來調整傳輸能量、速率。 事實上,(P4)問題所提方案繼承了(P1)、(P2)、(P3)問題所提方案的設計原則。因此,作為一個(P1)、(P2)、(P3)問題所提方案的一般化版本,(P4)問題所提方案能滿足本論文的目標:一個最終傳輸能量與傳輸速率控制方案,用以提高 IEEE 802.11 隨意網路在穩定頻道、非定頻道之吞吐量。 In the recent decade, wireless ad hoc networks have received much attention, because they without infrastructures can served for different purposes, such as mobile ad hoc networks, wireless mesh networks, wireless sensor networks, or vehicular ad hoc networks. For wireless ad hoc networks, nowadays the most widely adopted medium access control (MAC) protocol is the IEEE 802.11 standard distributed coordination function (DCF). In IEEE 802.11 ad hoc networks, the growing demands for various bandwidth-hungry applications have rendered it more and more important to improve network throughputs. In this dissertation, we focus on the following problems which are the main challenges to enhance throughputs of IEEE 802.11 ad hoc networks, by means of tuning the transmission power and transmission rate. (P1) A transmission power control (TPC) scheme can improve the throughput of IEEE 802.11 ad hoc network with one non-fading channel and one transmission rate. (P2) A transmission power/rate control (TPRC) scheme can improve the throughput of IEEE 802.11 ad hoc network with one non-fading channel and multiple transmission rates. (P3) A TPC scheme can improve the throughput of IEEE 802.11 ad hoc network with one fading channel and one transmission rate. (P4) A TPRC scheme can improve the throughput of IEEE 802.11 ad hoc network with one fading channel and multiple transmission rates. For (P1), by means of minimizing ceased areas, a new TPC scheme is proposed so as to enhance the spatial reuse in IEEE 802.11 ad hoc networks. A ceased area is associated with a transmitter-receiver pair, and all other nodes within it should keep silent in order to have packets reliably received between the transmitter-receiver pair. For (P2), a new TPRC scheme is proposed. The design principle of the scheme is to utilize the space-time resource efficiently. With this purpose, a new measure, named STPB, is introduced, which represents the space-time resource consumption per bit. The scheme can minimize STPB by selecting transmission power and transmission rate. Based on the proposed scheme for (P1), a new TPC scheme tuning transmission power according to the scale of fading is proposed for (P3). Based on the proposed scheme for (P2), a new TPRC scheme tuning transmission power (rate) according to the scale of fading (the moving average of channel gain) is proposed for (P4). In fact, the proposed scheme for (P4) inherits the design principles from the schemes for (P1), (P2), and (P3). Hence, as a general version of the schemes for (P1), (P2), and (P3), the scheme for (P4) can satisfy the objective of this dissertation: one final scheme for IEEE 802.11 ad hoc networks, in order to improve throughputs in non-fading and fading channels by power/rate control. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/48157 |
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