臺灣博碩士論文加值系統

由於無線通技術的進步，使得人們可以在移動的同時進行通訊，無線通訊幫助人們擺脫實體線路的束縛，有越來越多根基在無線技術之上的應用正在被開發及商業化，近年來有一種新型態被稱為「行動無線區域網路」(Mobile Ad Hoc Network)的網路型態正引起越來越多的關注。
「行動無線區域網路」是一種完全無線的網路，不須透過任何基地台或網路擷取點而進行通訊，有別於GSM及現有的無線區域網路在基地台及基地台之間仍須有線聯結的架構，行動無線網路不須任何的基礎建設及中央控制設備，在這樣子的一個網路型態中網路中的任何一點都可以是行動點而且可以在特定範圍內任意移動，所以由行動點組成的網路拓撲結構變化非常快速，因此造成行動無線區域網路在運作時封包如何繞路的問題變的很困難。
在此論文中提出了一個新的且有效率的繞路協定稱為「方向性繞路協定」，適合應用在行動無線區域網路上，在論文中將會詳細討論方向性繞路協定的細節及效能模擬的方法，並且會將方向性繞路協定的效能和現有的方法作比較來展示在效能上的改進。

An ad hoc network consists of mobile nodes without infrastructure and centralized controlling center. Mobile nodes can be laptop computers, notebooks, PDAs, and other devices. Each mobile node is supposed to be installed an antenna. Packets are transmitted through radio channel by the antenna between mobile nodes without the help of a transmission line. Besides, nodes are allowed to move around anywhere within an area of blurry size at any time. The border of the area within which mobile nodes are allowed to move around is blurry but around a certain range. Ad hoc networks are useful and can be easily applied in different scenarios. For example, in a conference venue, attendants may change their seats or walk around in the venue but they don’t go outside the venue. The venue area is the so-called blurry area above. Each of the attendants takes a notebook or PDA and run the system in ad hoc mode. The attendants can communicate to one another by ad hoc network without any wire or infrastructure deployment. The communication among the attendants includes audio, video, electronic file etc. To take another example as in the military mission, a group of people are sent to a dicky place to perform the action. It’s difficult to construct the communication infrastructure and the troops must move to different places all the time. Soldiers can use ad hoc network to talk to one another conveniently.
Recently, short-range wireless technology, such as IEEE802.11[10], is growing mature and coming to be commercialized. In the IEEE802.11 specification, it defines the physical and MAC layer of a short-range wireless communication standard. The radio transmission range in IEEE802.11 is about 200 to 300 meters. That means mobile nodes must be within that range to communicate to one another. The node which is outside the range loses the connectivity with other nodes. Routing algorithms in ad hoc networks can extend the geographical communication range without any change of the original physical and MAC layer

Contents
Chapter 1. Introduction……………………………….……..……………1
Chapter 2. Related Protocols…………………………….………….……4
2.1 IEEE 802.11 Wireless Local Area Networks……………………………4
2.2 Dynamic Source Routing…………………………………..……………6
2.2.1 Overview of Dynamic Source Routing……………………………6
2.2.2 Path Discovery Phase………………………………………..…….7
2.2.3 Path Maintenance…………………………………….……....……9
2.3 Ad-Hoc On Demand Distance Vector Routing…………………………11
Chapter 3. The Direction-Aware Routing Protocol(DARP)……..14
3.1 Overview of direction-aware routing protocol…………………...……14
3.2 Broadcast and Unicast in Wireless Medium……………………....…16
3.3 Basic Operation of Direction-Aware Routing Protocol……………...…19
3.4 DARP with homogeneous Life-Depth………………………...….……25
3.5 DARP with heterogeneous Life-Depth……………………...…………30
3.6 Comparison of DARP homogeneous case and DARP
heterogeneous case………………………………………………….….37
3.7 DARP overall states……………………………………….…….…..…38
Chapter 4. Simulation results………………………………...……..…40
4.1 Simulation of usual scenarios in the
ad hoc networks………………………………………….……..…40
4.2 Simulation methods of DARP and DSR……….…………….……47
4.3 Simulation results of DARP and DSR……………………….……53
Chapter 5. Conclusions……………………………………………….….59
References………………………………………………...…………………60

[1] D. B. Johnson and D. A. Maltz, “Dynamic Source Routing in Ad-Hoc Wireless Networks,” Mobile Computing, T. lmielinski and H. Korth, Eds.,Kluwer,1996, pp. 153-81.
[2] Broch, D. B. Johnson and D. A. Maltz, “The Dynamic Source Routing Protocol for Mobile Ad Hoc Networks,” IETF Internet draft, draft-ietf-mannet-dsr-01.txt, Dec.1998.
[3] Elizabeth M.Royer and Chai-Keong Toh, “A Review of Current Routing Protocols for Ad Hoc Mobile Wireless Networks,” IEEE Personal Communications, April 1999.
[4] C. E. Perkins and E. M. Royer, “Ad Hoc On Demand Distance Vector Routing,” Mobile Ad-Hoc Network Working Group, IETF,Aug 1998.
[5] Gavin Holland and Nitin Vaidya , “Analysis of TCP Performance over Mobile Ad Hoc Networks,” Fifth Annual ACM/IEEE International Conference on Mobile Computing and Networking, August 1999.