臺灣博碩士論文加值系統

在傳統的無線網路中加入多跳的能力，使用者除了可以直接跟基地台或存取點直接夠通、傳送資料外，還可以透過轉送中繼站（固定式轉傳中繼站或具有轉傳能力的移動端點）來傳送資料到基地台或存取點。在多跳式無線網路中，因為有轉送中繼站的存在，連線會被分為數段較短的路徑，因此需要的傳送功率較小。因為傳送的功率變小，對鄰近網路的造成的干擾也變小，所以系統效能能夠得到改善。此外，透過多跳/轉傳功能，甚至能夠覆蓋傳統無線網路的訊號死角。綜合以上論點，可以了解多跳式無線網路對增進系統效能和增加系統覆蓋率來說，是一個不錯的方法。
在這篇文章中，我們將會介紹多跳式技術，和幾個多跳式技術與無線網路、蜂巢式系統結合的方法。此外，我們會介紹一個多跳式無線網路的模型，並且介紹一個考慮了衰減通道對容量的影響的路徑選擇方法。而模擬結果也顯示了對於系統容量有大幅的改善。

Add multihop capability to the traditional wireless network, the users are able to transmit data directly to the access point or through relay stations (fixed relay stations or mobility nodes with elay capability) to relay their traffic to access point. In a multihop wireless network, the link is divided into some shorter paths requiring less transmit power and hence creates less interference to the nearby cells. With less interference, the system performance is improved, and more users can be accommodated in the system. In addition to capacity improvement and power saving, another important benefit is to enlarge the coverage. Actually, with the use of multihop/relaying, the dead spots can be eliminated effectively and hence the coverage of the system can be enhanced. From the above discussions, it is so clear that multihop architecture is a promising method to the performance and coverage improvement of wireless network system.

In this work, we introduced the multihop technique and showed some multihop cellular/wireless architectures. In this proposal, we proposed a multihop model, and introduced a routing selection scheme by considered the effect of fading on capacity. And the result shows that the system capacity was increased.

Contents
Abstract(Chinese). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
Abstract(English). . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Related Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4 Overview of the Thesis . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Ad Hoc Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Multihop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Nakagami-m Fading Channel . . . . . . . . . . . . . . . . . . . . . . 14
2.4 The Channel Capacity . . . . . . . . . . . . . . . . . . . . . . . . . 19
3 Multihop Relay Communication System . . . . . . . . . . . . . . . . . . 21
3.1 Relay Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2 The number of user limit . . . . . . . . . . . . . . . . . . . . . . . 24
3.3 Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.3.1 The Orthogonal Channel . . . . . . . . . . . . . . . . . . . . . . . 26
4 Multihop Wireless Systems Routing Selection . . . . . . . . . . . . . . 29
4.1 Proposed Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1.1 System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1.2 Channel Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.1.3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
4.2 Simulation Result . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Vita . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41


List of Figures
1.1 Multihop Wireless Network. . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Multihop wireless network communicate directly . . . . . . . . . . . . . 9
2.2 Multihop wireless network communicates without Base Station. . . . . . 10
2.3 Traffic Blancing . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4 Dead Spot Coverage . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.5 The PDF of Nakagami-m. . . . . . . . . . . . . . . . . . . . . . . . . 16
2.6 Rayleigh fading persecond with a maximum Doppler shift of 10Hz . . . . 17
2.7 Rayleigh fading persecond with a maximum Doppler shift of 100Hz. . . . 18
2.8 The channel capacity versus SNR . . . . . . . . . . . . . . . . . . . 20
3.1 The Average Delay of that relaying via FRS and MRS . . . . . . . . . . 23
3.2 Benefit of limites the number of user. . . . . . . . . . . . . . . . . 25
3.3 The Capacity with 1 to 3 hops. . . . . . . . . . . . . . . . . . . . . 27
4.1 Proposed System Model. . . . . . . . . . . . . . . . . . . . . . . . . 30
4.2 The Capacity versus Distance . . . . . . . . . . . . . . . . . . . . . 32
4.3 The Capacity versus a/N0 . . . . . . . . . . . . . . . . . . . . . . . 33
4.4 The System Capacity versus the number of User. . . . . . . . . . . . . 35
4.5 The System Capacity versus SNR . . . . . . . . . . . . . . . . . . . . 36
4.6 The System Capacity versus the number of User, with Interference . . . 37

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