臺灣大學: 電機工程學研究所廖婉君張嘉宏Chang, Chia-HungChia-HungChang2013-03-272018-07-062013-03-272018-07-062011http://ntur.lib.ntu.edu.tw//handle/246246/253968無線網格網路(Wireless Mesh Networks, WMNs) 因為具有較低的佈建成本，易於維護且能快速佈署，使之成為廣受歡迎的無線寬頻架構。在這類的網路中，節點通常是固定不動的，且部分節點被視為閘道(Gateway)，可直接透過有線連上網際網路。多路徑路由(multipath routing)藉由將流量分散到多個傳輸路徑中，是一個很有希望來提升系統效能的方式。藉由將流量分散到網路資源較少被使用的地方，多路徑路由可以減少網路的雍塞，進而提高網路的使用率，以及達到網路各處流量的平衡。目前已知為了提升無線網格網路系統效能所設計的多路徑路由方式，並沒法好好利用網路中的多個閘道存在的特性。因此，在這本論文中，我們的目標是在多閘道的無線網格網路中，提高多路徑路由所能達到的效能提升。 我們先為多閘道的無線網格網路提出一個新的多路徑路由演算法，取名叫2CPR。 在2CPR中，路由的選擇是可以抵達不同Gateways的路徑且路徑彼此間干擾最小。我們所提出的2CPR 可以有考慮到不同資料流之間的連結標準(link metrics) 相搭配。 此外，我們還用數學理論來分析2CPR的效能。 在這本論文的第二部分，我們將我們的研究延伸到有網路編碼的網路上。網路編碼有兩種，分別作用在媒體層(MAC-layer)跟實體層(PHY-layer)上。對作用媒體層的網路編碼，大多的研究集中在知曉網路編碼的路由上，以及了解系統效能提升的程度。而雖然在實體層進行網路編碼的效能似乎能夠比媒體層上做網路編碼來的好，關於實體層網路編碼的研究卻還很少。因此，我們對知曉網路編碼的多路徑路由提供了一個理論架構。模擬結果顯示在實體層進行網路編碼能夠比媒體層上進行網路編碼明顯提高網路效能。而且，在多閘道的無線網格網路下，在實體層進行網路編碼可以讓多路徑路由比在傳統網路下提高四倍的效能。這也表現出在多閘道的環境中設計知曉網路編碼的多路徑路由的重要性。 這本論文研究多路徑路由在多閘道的環境中的設計議題。不論是對於有沒有使用網路編碼的無線網格網路，它都提供了路由設計決策。此外，它還提供了能進一步提升網路效能的多路由路徑演算法。Wireless mesh networks (WMNs) have gained popularity due to its low up-front cost, easy network maintenance, and fast deployment for broadband wireless access. In WMNs, nodes are typically stationary and some of them may have direct connections to wired networks and serve as the gateways to access the Internet. To improve system throughput, multipath routing is a promising solution to distributing traffic among multiple paths instead of concentrating on one path as in unicast routing. By deviating traffic to underutilized network resource, multipath routing could better reduce congestion in “hot spots,” thereby improving network utilization and achieving load balancing. Existing multipath routing schemes have been designed for system throughput improvement in mesh networks. However, they do not fully exploit the fact that multiple gateways may co-exist in the network. Therefore, in this dissertation, we aim to improve the throughput that multipath routing can achieve in WMNs with multiple gateways. We start by proposing a new routing algorithm called two concurrent path routing (2CPR) for multi-gateway wireless mesh networks. In 2CPR, routing paths are selected in such a way that they are destined to different gateways and their inter-path interference is minimized. The proposed 2CPR scheme can be easily integrated with existing link metrics designed for tackling inter-flow interference. We also theoretically determine the throughput of 2CPR. In the second part of this dissertation, we extend our study of multipath routing to the multi-gateway WMNs with applying of network coding. There are two types of network coding, MAC-layer network coding and physical layer based network coding. For MAC-layer network coding, many literatures have been devoted to provide coding-aware routing and identify the degree of throughput improvement. But for physical layer based network coding, which is a promising technique to improve the network throughput more than MAC-layer network coding, no research related with coding-aware routing and throughput improvement has been found. Therefore, we provide a theoretical framework for coding-aware multipath routing in multi-gateway WMNs. The simulation results show that physical layer based network coding can significantly improve the network throughput than MAC-layer network coding, and coding-aware routing is necessary for both coding methods. Moreover, in multi-gateway WMNs with the applying of pNC, multipath routing can benefit the network throughput almost four times more than the one with traditional approach. It shows the necessity to design the coding-aware multipath routing in multi-gateway WMNs. This dissertation investigates the multipath routing in multi-gateway WMNs. It gives much insight into the routing design strategy in WMNs with/without the applying of network coding. In addition, it provides the multipath routing algorithm in which network throughput can be further improved in the targeted WMNs.1459920 bytesapplication/pdfen-US無線網格網路多閘道多路徑路由網路編碼效能分析知曉網路編碼的多路徑路由Wireless Mesh NetworksMultiple GatewaysMultipath RoutingNetwork CodingThroughputCoding-Aware Routingthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/253968/1/ntu-100-D93921018-1.pdf