現今有許多無線網路傳輸技術其中以正交分頻多工最常被使用，搭配合作式網路以及多使用者環境，藉由使用者之間互相協助傳遞訊息至目的端來形成一分散式天線陣列，進而提供空間分集增益。在頻譜有限的情況下，使用感知無線電能有效的提高頻譜的使用率，考量在不干擾主用戶傳輸的情形下，透過已知各傳輸路徑的通道狀態，做最佳的資源配置，可以有效的提高系統效能。

本論文考慮一個正交分頻多工暨多使用者合作式感知無線電解碼傳遞網路，以共同頻譜存取機制做資源配置，在主要使用者能忍受的干擾下，讓感知無線電使用者的傳輸率以及使整體能源效率最佳化，最佳化問題包含了子載波配對、功率分配與使用者選擇，其中功率分配除了考慮來源以及中繼端有各自的最大功率限制外，也必須對主用戶的功率干擾在一個門檻值下，子載波配對、功率分配與使用者選擇形成一個混合整數規劃問題。為了在合理的成本下解決此複雜的混合整數規劃問題，本論文提出了混合型基因演算法，在混合型基因演算法中，染色體切割成三個部分，第一部分為整數型的使用者選擇，第二部分為整數型的子載波配對，第三部分為實數型的功率分配，本論文同時也設計了一新型之染色體初始化方法，將目標涵數寫成凸函數的形式產生染色體初始值，再將此初始值代入提出的混和型基因演算法。相關的模擬結果顯示，在不同的限制考量下，混合型基因演算法相較於其他論文的方法而言，擁有更加優越的系統效能。

Orthogonal frequency division multiplexing (OFDM) systems are a promising communication technique nowadays. Meanwhile, cooperative networks and multi-user environment are common transmission technique in which a distributed antenna array can be created to provide spatial diversity gains by relaying each others messages to the destination based on the channel state information. Also, cognitive radio (CR) can effectively improve the spectrum efficiency. This thesis presents an efficient algorithm for joint subcarrier pairing and power allocation in multi-user OFDM-based cognitive decode-and-forward (DF) relay network. We aim to maximize the sum rate of the CR users by effectively power allocation, subcarrier allocation, and user select under the individual power constrains. The source and the relay with the interference introduced to the primary user (PU) being kept below a tolerable range. Such a joint consideration become a mixed integer programming (MIP) problem. To resolve MIP problem, a novel genetic algorithm (GA) is addressed, which tackles all of these issues as a whole and free of extra assumptions made in previous works to simplify the problem. A new initialization is also addressed to achieve better performance. Simulation results show that the proposed method outperforms the state-of-the-art works.

[1]R. v. Nee and R. Prasad,OFDM for Wireless Multimedia Communica- tions, Artech House, 2000
[2]W. Y. Zou and Y. Wu, “COFDM: An overview,”IEEE Trans. Broad- casting, vol. 40, pp. 1–8, Mar. 1995.
[3]A. Sendonaris, E. Erkip, and B. Aazhang,“User cooperation diversity- part I: system description”and “User cooperation diversity-part II: implementation aspects and performance analysis,”IEEE Trans. Com-
mun., vol. 51, no. 11, pp. 1927-1938, 1939-1948, Nov. 2003.
[4]K. J. R. Liu, A. K, W. S. Sadek, and A. Kwasinski,Cooperative Com- munications and Networking. Cambridge University Press, 2008.
[5]National Telecommunications and Information Administration (NTIA),
“FCC Frequency Allocation Chart,” 2003. [Online]. Available: http://www.ntia.doc. gov/osmhome/allochrt.pdf.
[6]J. Mitola and G.Q. Maquire Jr., “Cognitive radio: Making software radios more personal,”IEEE Pers. Commun., vol. 6, no. 4, pp. 13-18,
Aug. 1999.
[7]E. Hossain and V. K. Bhargava, ed. Cognitive Wireless Communication Networks. Springer, 2007.
[8]P. Kaligineedi, G. Bansal, and V. K. Bhargava, “Power loading algo- rithms for OFDM-based cognitive radio systems with imperfect sens- ing,” IEEE Trans. Wireless Commun., vol. 11, no. 12, pp. 4225-4230, Dec. 2012.
[9]Y.-C. Liang, K.-C. Chen, G.Y. Li, and P. Mahonen, “Cognitive radio networking and communications: an overview,” IEEE Trans. Vehicular Technology, vol. 60, no. 7, pp. 3386-3407, Sep. 2011.
[10]Qi, Zhang, et al. ”Power allocation for regenerative relay channel with Rayleigh fading.” Vehicular Technology Conference, 2004. VTC 2004- Spring. 2004 IEEE 59th. Vol. 2. IEEE, 2004.
[11]L. Vandendorpe, R. Duran, J. Louveaux, and A. Zaidi, “Power allo- cation for OFDM transmission with DF relaying,”in Proc. IEEE Int.
Conf. Commun., pp. 3795-3800, 2008.
[12]J. Zhu et al.,“On optimal power allocation for downlink non-orthogonal multiple access systems,”IEEE J. Sel. Areas Commun., vol. 35, no. 12, pp. 2744–2757, Dec. 2017.
[13]T. T. Duy, and H. Y. Kong, “Performance Analysis of Mixed Amplifyand-Forward and Decode-and-Forward Protocol in Underlay Cognitive Networks,”China Communications, vol. 13, no. 3, pp. 115– 126, Mar. 2016.
[14]Y. Li, W. Wang, J. Kong, and M. Peng,“Subcarrier pairing for amplify- and- forward and decode-and-forward OFDM relay links,”IEEE Com-
mun. Lett., vol. 13, no. 4, pp. 209-211, Apr. 2009.
[15]Ying, Wang, et al. ”Power allocation and subcarrier pairing algorithm for regenerative OFDM relay system.”Vehicular Technology Conference, 2007. VTC2007-Spring. IEEE 65th. IEEE, 2007.
[16]Y. Li, W. Wang, J. Kong, W. Hong, X. Zhang, and M. Peng, “Power allocation and subcarrier pairing in OFDM-based relaying networks,”
in Proc.IEEE Int. Conf. Commun., pp. 2602-2606, May. 2008.
[17]X. Li, Q. Zhang, G. Zhang and J. Qin, “Joint power allocation and subcarrier pairing for cooperative OFDM AF multi-relay networks,”
IEEE Commun. Lett., vol. 17, no. 5, pp. 872-875, May 2013.
[18]A. Minasian, R. Adve, and S. ShahbazPanahi, “Optimal resource al- location in energy harvesting amplify-and-forward relay networks,”in Proc. IEEE GlobalSIP, Dec. 2013, pp. 363–366.
[19]M. Shaat and F. Bader, “Asymptotically optimal subcarrier matching and power allocation for cognitive relays with power and interference constraints,”in Proc.IEEE Wireless Commun. and Networking Con- ference, pp. 663-668, Apr. 2012
[20]M. Shaat and F. Bader, “Asymptotically optimal resource allocation in OFDM-Based cognitive networks with multiple relays,”IEEE Trans. Wireless Commun., vol. 11, no. 3, pp. 892–897, Mar. 2012.
[21]G. Bansal, M. J. Hossain, V. K. Bhargava, and T. Le-Ngoc,“Subcarrier and power allocation for OFDMA-based cognitive radio systems with joint overlay and underlay spectrum access mechanism,”IEEE Trans. Vehicular Technology, vol. 62, no. 3, pp. 1111-1122, Mar. 2013.
[22]A. Jamalipour, T. Wada, and T. Yamazato, “A tutorial on multiple access technologies for beyond 3G mobile networks,”IEEE Commun. Mag., vol. 43, pp. 110–117, Feb. 2005.
[23]H. Liu and G. Li,OFDM Based Broadband Wireless Networks Design and Optimization. John Wiley & Sons, 2005.
[24]IEEE Standard for Wireless Regional Area Networks (WRAN)—Part22 Cognitive Wireless RAN Medium Access Control (MAC) and Physical
Layer (PHY) Specifications Policies and Procedures for Operation in the TV Bands,IEEE
[25]IEEE Standard for Local and Metropolitan Area Networks—Part
16 AirInterface for Broadband Wireless Access Systems,IEEE Std 802.16TM2009, May 2009.
[26]R. Hoshyar, M. Shariat, and R. Tafazolli, “Subcarrier and power al- location with multiple power constraints in OFDMA systems,”IEEE Commun. Lett., vol. 14, no. 7, pp. 644–646, Jul. 2010.
[27]H. Al-Tous and I. Barhumi, “Resource allocation for multiple-sources single-relay cooperative communication OFDMA systems,”IEEE Trans. Mobile Comput., vol. 15, no. 4, pp. 964–981, Apr. 2016.
[28]G.P.S. Tej, T. Nadkar, V. M. Thumar, U. B. Desai, and S. N. Mer- chant, “Power allocation in cognitive radio: single and multiple sec- ondary users,”in Proc.2001 IEEE Wireless Commun. Netw. Conf., pp.
1420–1425.
[29]C.-N. Hsu, H.-J. Su, and P.-H. Lin,“Joint subcarrier pairing and power allocation for OFDM transmission with decode-and-forward relaying,” IEEE Trans. Signal Process., vol. 59, no. 1, pp. 399–414, Jan. 2011.
[30]H. W. Kuhn, “The Hungarian method for the assignment problem”
.Naval research logistics quarterly, 1955, 2.1‐2: 83-97.
[31]F. F. Digham,“Joint power and channel allocation for cognitive radios,” in Proc.IEEE WCNC, Las Vegas, NV, Apr. 2008, pp. 882–887.
[32]T. Weiss, J. Hillenbrand, A. Krohn and F. K. Jondral, “Mutual in- terference in OFDM-based spectrum pooling systems,”in Proc.IEEE
Vehicular Technol. Conf., vol. 4, pp. 1873-1877, May, 2004
[33]Y. Wang, F. Chen, and G. Wei, “Adaptive Subcarrier and Bit Al- location for Multiuser OFDM System Based on Genetic Algorithm,”
Communications, Circuits and Systems, vol. 1, pp. 242-246, 2005.
[34]A. Sendonaris, E. Erkip, and B. Aazhang,“User cooperation diversity. Part I: System description,”IEEE Trans. Commun., vol. 51, no. 11, pp. 1927–1938, Nov. 2003.
[35]K. Letaief and W. Zhang, “Cooperative communications for cognitive radio networks,”Proc.IEEE, vol. 97, no. 5, pp. 878–893, May 2009.
[36] K. Singh, A. Gupta, and T. Ratnarajah,“Energy efficient resource allo- cation for multiuser relay networks,”IEEE Trans. Wireless Commun., vol. 16, no. 2, pp. 1218–1235, Jan. 2017.
[37]J. Mitola, G.Q. Maquire Jr.,“Cognitive radio: Making software radios more personal,”IEEE Pers. Commun., vol. 6, no. 4, pp. 13-18, Aug.
1999.
[38]Y.-C. Liang, K.-C. Chen, G.Y. Li and P. Mahonen, “Cognitive radio network- ing and communications an overview,”IEEE Trans. Vehicular
Technology, vol. 60, no. 7, pp. 3386-3407, Sep. 2011.
[39]T. Weiss, J. Hillenbrand, A. Krohn and F. K. Jondral, “Mutual in- terference in OFDM-based spectrum pooling systems,”in Proc.IEEE
Vehicular Technol. Conf., vol. 4, pp. 1873-1877, May, 2004.
[40]S. Boyd and L. Vandenberghe,Convex Optimization. Cambridge Cam- bridge University Press, 2004.
[41]W. Yu and R. Lui,“Dual methods for nonconvex spectrum optimization of multicarrier systems,”IEEE Trans. Commun., vol. 54, no. 7, pp.
1310-1322, July, 2006.
[42]M. Shaat and F. Bader, “Asymptotically optimal resource allocation in OFDM-based cognitive networks with multiple relays,”IEEE Trans.
Wireless Commun., vol. 11, no. 3, Mar. 2012.
[43]H.-Y. Lu and W.-H. Fang,“Joint transmit/receive antenna selection in MIMO systems based on the priority-based genetic algorithm,”IEEE
Antennas and Wireless Propagation Letters, vol. 6, pp. 588-591, 2007.
[44]J.H. Holland,Genetic Algorithms. Sci. Am. 1992.
[45]T. Yalcinoz and H. Altum, “Power economic dispatch using a hybrid genetic algorithm,”IEEE Power Eng. Rev., vol. 21, pp. 59-60, 2001.
[46]S. Boyd and A. Mutapcic,“Subgradient methods,” Lecture Notes of EE364b, Stanford University, Stanford, CA, Spring quarter 2007-2008.
[47]C.-H. Chen, C.-L. Wang, and C.-T. Chen“, A resource allocation scheme
for cooperative multiuser OFDM-based cognitive radio systems,”IEEE Trans. Commun., vol. 59, no. 11, pp. 3204–3215, Nov. 2011.
[48]H. Al-Tous and I. Barhumi, “Resource allocation for multiple-sources single-relay cooperative communication OFDMA systems,”IEEE Trans. Mobile Comput., vol. 15, no. 4, pp. 964–981, Apr. 2016.