對於隨機變動的環境，而且有大量的資料量要去處理，以及各個狀況要去做 整合，採用 Opportunistic Scheduling 方式決定合適的傳輸速率，以符合大多數要 求服務的使用者的需求，加上我們提出的演算法更是可以加乘效果。
只要使用者收到足夠解碼的編碼封包即可完成服務。我們以此為基礎，設計 出可以加強服務的 Opportunistic Scheduling，而且只需了解每一位使用者目前收
到多少封包，一種簡單的設計，運算每一位使用者的值。另外套用 Integer Programming，每一個時程當中，從眾多組合中去逼近一組較佳的傳輸速率組合。
篩選機制的加入，讓過去一段時間 SNR 狀況差的使用者群可以優先設定基地台傳 輸速率，使他們有更高的機會收到來自基地台的封包。如此一來，此子群使用者 獲得較優的服務。
透過值制定可以快速且簡便了解各個使用者目前狀態，更是縮小排程計算 複雜度，同時又能依據每一個時程中使用者的變化服務使用者群，計算並給予使 用者群合適的傳輸速率。
未來研究方向可更深入探討對於值的設定與應用可以更為廣泛與精煉，讓 基地台更能清楚了解每一個時程中每一位使用者的變化，或是設定使用者有各自 相異所需足夠編碼封包數量設定，觀察此環境下的變化，抑或是試著將此演算法 套用在急需大量運算的系統，範圍的取捨可讓計算更為精簡。
50
參考文獻
[1] Quang Le-Dang, Tho Le-Ngoc, and Quang-Dung Ho, “Opportunistic Multicast Scheduling with Erasure-Correction Coding over Wireless Channels,” in Proc. 2010 IEEE ICC.
[2] Jianwei Huang, Vijay G. Subramanian and Rajeev Agrawal, Randall Berry,
“Downlink Scheduling and Resource Allocation for OFDM Systems,” IEEE Trans.
Wireless Commun., vol. 8, no.1, pp. 288-296, Jan. 2009.
[3] Quang-Dung Ho and Tho Le-Ngoc, “Adaptive Opportunistic Multicast Scheduling Over Next-Generation Wireless Networks,” Wireless Pers Commun, pp. 483-500, 2012.
[4] Wen Huang and Kwan L. Yeung, “On Maximizing the Throughput of Opportunistic Multicast in Wireless Cellular Networks with Erasure Codes,” in Proc. 2011 IEEE ICC.
[5]D.J.C. MacKay, “Fountain Codes,” IEE Proc.-Commun. vol.52, no.6, pp.
1062-1068, Dec. 2005.
[6] Stephen B. Wicker and Vijay K. Bhargava ,Reed-Solomon Codes and Their Applications, Wiley-IEEE Press, 1999.
[7] U. C. Kozat,“On the Throughput Capacity of Opportunistic Multicasting with Erasure Codes,” in Proc. 2008 IEEE INFOCOM, pp.1193-1201.
[8] Hua Chen and John S. Baras, “A Distributed Opportunistic Scheduling Protocol for Multi-Channel Wireless Ad-Hoc Networks,” in Proc. 2012 IEEE GLOBECOM, pp.
292-297.
[9] Praveen Kumar Gopala and Hesham El Gamal,“Opportunistic Multicasting,” in Proc. the Asilomar Conference on Signals, Systems and Computers, Pacific Grove, CA, Nov. 2004.
51
[10]Guocong Song and Ye Li, ”Utility-Based Resource Allocation and Scheduling in OFDM-Based Wireless Broadband Networks,” IEEE Commun. Mag., vol. 43, pp.
127-134, Dec. 2005.
[11]Euntaek Lim and Sehun Kim, “Transmission Rate Scheduling With Fairness
Constraints in Downlink of CDMA Data Networks,” IEEE Trans. Veh. Technol., vol.54, no.1, pp. 328-337, Jan. 2005.
[12]Qi Qu and Ulas C. Kozat, “On the Opportunistic Multicasting in OFDM-based Cellular Networks,” in Proc. 2008 IEEE ICC, pp. 3708-3714.
[13]Q. Spencer and M. Haardt, “Capacity and downlink transmission algorithm for a multi-user MIMO channel,” in Proc. 36th Asilomar Conf. on Signals, Systems, and Computers, Pacific Grove, CA, IEEE Computer Society Press, Nov. 2002.
[14]S. Sanayei and A. Nosratinia, “Opportunistic downlink transmission with limited feedback,” IEEE Trans. Inf. Theory, vol. 53, no. 11, pp. 4363-4372, Nov. 2007.
[15]Jung-Tsung Tsai, “Transmission Rate Scheduling and Stopping for Time-Sensitive Multicast Stream Traffic in Cellular Networks,” IEEE Trans. Wireless Commun., vol.
13, no. 4, pp. 1754-1765 Apr. 2014.
[16]Youghe Liu and Edward Knightly, “Opportunistic Fair Scheduling over Multiple Wireless Channels,” in Proc. 2003 IEEE INFOCOM, pp. 1106-1115.
[17]Kent Wilken, Jack Liu, Mark Heffernan, “Optimal Instruction Scheduling Using Integer Programming,” in Proc. Assoc. Comput. Machinery Conf. Program. Language Design Implement. (PLDI), pp. 121-133, 2000.
[18]Miray Kas, Burcu Yargicoglu, Ibrahim Korpeoglu, and Ezhan Karasan, “A Survey on Scheduling in IEEE802.16 Mesh Mode,” IEEE Commun. Surveys Tutor., vol.12, no.2, pp. 205-221, Second Quarter 2010.
[19]Changho Suh, Seunghoon Park, and Youngkwon Cho, “Efficient Algorithm for Proportional Fairness Scheduling in Multicast OFDM Systems,” in Proc. IEEE Veh.
Technol. Conf., vol.3, pp.1880-1884, Jun. 2005.
52
[20]Richard O. Afolabi, Aresh Dadlani, and Kiseon Kim, ”Multicast Scheduling and Resource Allocation Algorithms for OFDMA-Based Systems: A Survey,” IEEE Commun. Surveys Tutor., vol.15, no.1, pp. 240-254, First Quarter 2013.
[21]Andrea Goldsmith ,Wireless Communications, Cambridge University Press, 2005.
[22] W. Stallings ,Wireless Communications and Networks, 2nd ed., Prentice Hall PTR, 2004.
[23] Kaveh Pahlavan and Prashant Krishnamurthy ,Principles of Wireless Networks, Prentice Hall PTR, 2002.