本篇論文，考慮放大後轉送合作式網路(AF Cooperative Networks)，中繼節
點具備了射頻獵能(Radio Frequency Energy Harvesting，RFEH) 的技術，其探討
了在中繼點能量有限時，達成SNR 需求之功率分配(Power Allocation)，提出中
繼點選擇策略(Relay Selection) 以延長網路生命週期(Network Lifetime)。合作式
網路中，多中繼點所提供之空間多樣性(Spatial Diversity)，不僅提高了網路傳
輸可靠度也增加了傳輸率。若中繼點須倚靠電力線供給電源，則必須增加額外
的建置成本且也缺乏機動性。因此我們考慮中繼點應用射頻獵能技術，收集周
圍環境中無線電波的能量，以轉換成電能，使得中繼節點可以自給自足，進一步
延長網路生命週期。本篇論文探討如何應用中繼點選擇策略，選出一個最佳中
繼點傳送訊號，而其餘未傳送訊號的中繼點則進行能量採集，增加電池電量。中
繼點的選擇方式，盡可能地減少平均傳送耗損的能量、降低浪費的能量以及提
高採集到的平均能量，以延長網路生命週期。論文中，我們使用整個網路之中斷
機率(Outage Probability) 來定義生命週期，即若網路之中斷機率低於系統標準
值，系統可正常運作的時間視為網路生命週期。而網路的中斷機率會隨著此中繼
點之電池所剩的能量減少而增加，所以網路的生命週期與中繼點的剩餘能量有密
切的關係。我們所提出的中繼點選擇策略與現有的其他四種選擇策略，皆將通
道資訊狀態(Channel State Information，CSI)、剩餘能量資訊(Residual Energy
Information，REI)，與能量採集資訊(Harvested energy information,HEI) 納入考
量。由於這些中繼點選擇策略都只跟個別中繼點的通道資訊狀態、剩餘能量資
訊，以及能量採集資訊有關，因此我們可以採用機會式載波偵聽(Opportunistic
Carrier Sensing，OCS) 的方式進行分散式的管理，讓每個中繼點根據各自通道及
電量資訊，即使不需要做資訊交換，亦可決定最佳中繼點，減少overhead。模擬
結果顯示，我們提出的中繼點選擇策略，在嚴謹的中斷機率標準值界定下，生命
週期表現最好。尤其是當中繼點數越來越多時，在歷經夠長的時槽後，其穩態中
斷機率能維持低於系統需求之中斷機率標準值，此系統可以維持無窮大的生命週
期。

In this thesis, we consider AF cooperative networks with multiple radio frequency energy-harvesting (RFEH) relays, and investigate power allocation and relay selection strategies to prolong the network lifetime since relays are battery-powered with limited energy. Through cooperation among multiple relays, reliability and transmission rate of cooperative networks are enhanced by exploiting spatial diversity. If relays rely on wireline power supplies, implementation cost must increase and mobility is lacked. Therefore, we consider relays apply RFEH technology to harvest energy by transferring ambient RF signal into electrical energy, so that they can be self-sustained. Consequently, the network lifetime can be further prolonged. In this thesis, we investigate relay selection strategies to choose one relay to forward messages while the others perform energy harvesting. Those selection strategies
aim to minimize the loss of energy dissipation, reducing wasted energy and increase the average harvested energy, in order to prolong the network lifetime. In this thesis, we define network lifetime based on the outage performance of the network. Specifically, if outage probability of network is lower than a threshold, the system is treated as "well-functioned", and the network lifetime is defined as the longest period in which network is well-functioned. From the expression of outage probability, network lifetime is related to the residual energy of relays.Compares with existing relay selection strategies which take Channel State Information(CSI),Residual Energy Information(REI), and/or Harvested Energy Information(HEI) into account, we proposed a novel relay selection scheme based on opportunity cost of each choice. Because the proposed scheme properly exploits CSI, REI, and HEI, the proposed scheme outperforms others with stringent outage requirement. Moreover, since all relay selection strategies require simply local CSI, REI, and HEI, they can be accomplished in a distributed manner through opportunistic carrier sensing without extra overhead.

論文審定書. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i
誌謝. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii
摘要. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
目錄. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
圖目錄. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
第一章簡介. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
第二章相關背景. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 射頻獵能技術. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 訊號電能多工處理. . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 相關文獻. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3.1 系統模型. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3.2 電量離散化設定. . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3.3 有限狀態馬可夫鍊. . . . . . . . . . . . . . . . . . . . . . . . 9
2.3.4 Greedy Switching 演算法. . . . . . . . . . . . . . . . . . . . 11
2.3.5 中斷機率. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3.6 模擬結果. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
第三章系統模型. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
第四章網路生命週期最大化. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1 可選中繼集合. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.2 網路生命週期定義. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3 中斷機率. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.4 延長網路生命週期之中繼點選擇策略. . . . . . . . . . . . . . . . . . 22
4.5 機會式載波偵聽. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
第五章模擬結果. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
第六章結論. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
參考文獻. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

[1] J. N. Laneman, D. Tse, and G. W. Wornell, “Cooperative diversity in wireless
networks: Efficient protocols and outage behavior,” IEEE Trans. Inform. Theory,
vol. 50, no. 12, pp.3062–3080, December 2004.
[2] J. N. Laneman and G. W. Wornell, “Distributed space-time coded protocols for
exploiting cooperative diversity in wireless networks,” IEEE Trans. on Inform.
Theory, vol. 49, no. 10, pp. 2415–2425, October 2003.
[3] A. Nosratinia, T. Hunter, and A. Hedayat, “Cooperative communication in
wireless networks, ” IEEE Commun. Mag., vol. 42, no. 10, pp. 74–80, October
2004.
[4] O. Ozel, K. Tutuncuoglu, J. Yang, S. Ulukus, and A. Yener, “Transmission with
energy harvesting nodes in fading wireless channels: optimal policies,” IEEE J.
Sel. Areas Commun., vol. 29, no. 8, pp. 1732–1743, September 2011.
[5] J. A. Paradiso and T. Starner, “Energy scavenging for mobile and wireless
electronics,” IEEE Trans. Pervasive Comput., vol. 4, no. 1, pp. 18–27, Jan.-March 2005.
[6] R. J. M. Vullers, R. V. Schaijk, H. J. Visser, J. Penders, and C. V. Hoof, “Energy harvesting for autonomous wireless sensor networks,” IEEE Solid-State Circuits Mag., vol. 2, no. 2, pp. 29–39, Spring 2010.
[7] I. Krikidis, S. Timotheou, and S. Sasaki, “RF energy transfer for cooperative
networks: Data relaying or energy harvesting?,” IEEE Commun. Lett., vol. 16,
no. 11, pp. 1772–1775, November 2012.
[8] X. Lu, P. Wang, D. Niyato, D. I. Kim, and Z. Han, “Wireless Networks with RF
Energy Harvesting: A Contemporary Survey,” IEEE Commun. Surveys and
Tutorials. , vol. 17, no. 2, pp.757–789, Second Quarter 2015.
[9] S. Bi, C. K. Ho, and R. Zhang, “Recent Advances in Joint Wireless Energy and
Information Transfer, ” arXiv preprint arXiv:1407. .0474v1, July 2014
[10] Y. Peng, Zi.Li, W. Zhang, D. Qiao, “Prolonging Sensor Network Lifetime
Through Wireless Charging,” IEEE Real-Time Systems Symposium
[11] M. Hajiaghayi, M. Dong, and B. Liang, “Maximizing Lifetime in Relay
Cooperation Through Energy-Aware Power Allocation, ” IEEE Trans. on Signal
Processing., vol. 58, no. 8, August 2010
[12] Y. Chen and Q. Zhao, “An integreated approach to energy-aware medium access for wireless sensor network,” IEEE Trans. Signal Processing, vol. 55, no. 7, pp. 3429– 3444, July 2007.
[13] Q. Zhao,L. Tong,and Y. Chen, “Energy-aware data-centric MAC for
application- specific sensor networks,” in Proc. IEEE Workshop on Statistical
Signal Processing, July 2005.
[14] Y. Chen and Q. Zhao, “Maximizing the lifetime of sensor network using local
information on channel state and residual energy,” in Proc.Conference on
Information Science and Systems (CISS) 2005.
[15] W.-J. Huang, Y.-W. P. Hong,and C.-C. J. Kuo, “Lifetime maximization for
Amplify-and-Forward cooperative networks,” IEEE Trans. Wireless Commun.,
May 2008. ., vol. 7, pp. 1800–1805
[16] Friedrich von Wieser (November 1914). Theorie der gesellschaftlichen
Wirtschaft [Theory of Social Economics]
[17] A. Bletsas, A. Khisti, D. P. Reed and A. Lippman, “A Simple Cooperative
Diversity Method Based on Network Path Selection,” IEEE Journal on selected
areas in communications, vol. 24, no. 3, March 2006
[18] V. Kuhn, F. Seguin, C. Lahuec and C. Person, “Enhancing RF-to-DC conversion efficiency of wideband RF energy harvesters using multi-tone optimization technique,” International Journal of Microwave and Wireless Technologies, pp.1-11 2014