在合作式網路中，中繼站扮演了關鍵的角色，特別是協調數個中繼站工作所需的協定決定了使用中繼站可達成的增益，使用較多的中繼點雖可提升傳輸穩定度，但也需付出較多的系統資源，因此有必要對合作式中繼協定的效能進行評估。這篇論文考慮了三種當下熱門，基於解碼後重送的合作式中繼協定，分別是中繼站全體參與合作、選擇單一最佳中繼站參與合作、中繼站分兩階段參與合作等方式，透過模擬與理論分析比較它們的效能，包含中斷機率和平均使用的中繼站數目，並討論多項關鍵的協定參數對合作式網路效能的影響。

In cooperative networks, the relay stations play an important role. In particularly, cooperat- ive relaying protocols for coordinating multiple relays determine the achievable gain of us- ing relays. A cooperative relay protocol that employs more relays to cooperate can improve the transmission reliability, but the improvement may come at the cost of more system res- ources consumed. Therefore, it is critical to evaluate the performance of cooperative relay- ing protocols. This thesis considers three state-of-the-art cooperative relaying protocols ba- sed on decode-and-forward, including all-participate cooperation, best relay selection coo- peration, and two-phase cooperation. Both theoretical analysis and simulations are used to analyze and compare their performance in terms of the outage probability and the average number of used relays. In addition, the impact of numerous key parameters on cooperative networks is discussed.

[1] J. N. Laneman, “Limiting analysis of outage probabilities for diversity schemes in fading channels”, in Proc. IEEE Globecom'03, vol. 3, pp. 1242 – 1246 vol.3, December 2003.
[2] Y-W. Hong, W.-J. Huang, F-H. Chiu, and C.-C. J. Kuo, “Cooperative communications in resource-constrained wireless networks”, IEEE Signal Processing Magazine, vol. 24, no. 3, pp. 47–57, May 2007.
[3] T. Wirth, L. Thiele, T. Haustein, O. Braz, and J. Stefanik, “Lte amplify and forward relaying for indoor coverage extension”, IEEE 72nd(VTC. 2010-Fall ), pp. 1–5, September 2010.
[4] J. Jose, Lei Ying, and S. Vishwanath, “On the stability region of amplify-andforward cooperative relay networks”, in Proc. IEEE ITW'09, pp. 620 – 624, October 2009.
[5] M. Yu and J. Li, “Is amplify-and-forward practically better than decode-andforward or vice versa?”, in Proc. IEEE ICASSP'05, vol. 3, pp. 365–368, March 2005.
[6] J. N. Laneman, D. N. C. Tse, and G. W. Wornell, “Cooperative diversity in wireless networks: Efficient protocols and outage behavior”, IEEE Trans. Information Theory, vol. 50, no. 12, pp. 3062 – 3080, December 2004.
[7] L. Y. Phee, M. Elkashlan, and I. B. Collings, “Outage probability and ser of multi-antenna fixed gain relaying in cooperative mimo networks”, in Proc. IEEE ICC'11, pp. 1–6, June 2011.
[8] K. H. Liu and H. H. Chen, “Probabilistic relay selection for fast selection cooperation in half-duplex wireless networks”, in Proc. IEEE Globecom'09, pp. 1–6, November 2009.
[9] Y. Jing and H. Jafarkhani, “Single and multiple relay selection schemes and their achievable diversity orders”, IEEE Trans. Wireless Commun, vol. 3, no. 8, pp. 1414 – 1423, March 2009.
[10] M. Abouelseoud and A. Nosratinia, “Opportunistic relay selection with a direct link”, in Proc. IEEE Globecom'10, pp. 1–5, December 2010.
[11] G. Farhadi and N. Beaulieu, “Fixed relaying versus selective relaying in multi-hop diversity transmission systems”, IEEE Trans. Wireless Commun, vol. 58, no. 3, pp. 956 – 965, March 2010.
[12] S. Ikki and M. H. Ahmed, “Performance analysis of incremental relaying cooperative diversity networks over rayleigh fading channels”, in Proc. IEEE WCNC'08, pp. 1311–1315, April 2008.
[13] W. Choi, D. I. Kim, and B. H. Kim, “Adaptive multi-node incremental relaying for hybrid-arq in af relay networks”, IEEE Trans. Wireless Commun, vol. 9, no. 2, pp. 505 – 511, 2010.
[14] T. Renk, H. Jaekel, and F. K. Jondral, “Incremental relaying with imperfect feedback in wireless cooperative networks”, in Proc. IEEE VTC'10, vol. 38, pp. 1–5, September 2010.
[15] M. D. Yacoub, J. C. S. S. Filho, and C. R. C. M. da Silva, “Simple closed-form solutions for level crossing rate and average fade duration in nakagami-m equal gain combining”, Information Theory and Its Applications, vol. 38, no. 25, pp. 1734 – 1735, December 2002.
[16] Y. Tokgoz and B. D. Rao, “The effect of imperfect channel estimation on the performance of maximum ratio combining in the presence of cochannel interference”, IEEE Trans. Veh. Technol, vol. 5, no. 55, pp. 1527 – 1534, September 2009.
[17] Y. A. Al-Zahrani, N. K. Al-Mutairi, Y. Al-Hodhayf, and A. Al-Shahrani, “Performance of antenna selection for maximum ratio combining mimo system”, in Proc. IEEE ICCSN'11, pp. 642 – 645, May 2011.
[18] N. Mekloi, “Outage probability for mmse linear diversity in a non-gaussian fading environment”, Information Theory and Its Applications, pp. 1–4, December 2008.
[19] Cailian Chen, Hongyi Yu, Caiyao Shen, and Ke Yang, “Networking and digital society, 2009. icnds ’09. international conference on”, in Proc. IEEE ICASSP'05, vol. 1, pp. 281–284, May 2009.
[20] 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 Commun, vol. 24, no. 3, pp. 659 – 672, March 2006.