在次世代蜂巢式網路中，透過設置中繼節點的技術是一種可以延伸範圍和增加吞吐量的選擇。在LTE-A中繼網路中，由於基地台不知道中繼節點底下行動台的通道狀況，且中繼鏈路及存取鏈路的速率不匹配，導致保留給每個行動台的佇列會出現緩衝區溢位及缺位的問題。在這篇論文中，首先我們提出分析模型去推導每個行動台的緩衝區溢位機率及缺位機率。並提出流量控制及頻寬配置機制去處理緩衝區溢位及缺位的問題. 接著藉由模擬驗證分析模型的準確性和機制的效能。

Relay network is one of the candidates for extending coverage or enhancing throughput of the next generation cellular systems. In LTE-A relay networks, the based station (BS) does not know the channel quality of each mobile station (MS) served by its subordinate relay nodes (RNs). At the RN, the queues reserved for its serving MSs may have buffer overflow and/or buffer underflow problems due to the mismatch of the data rates between the access link and the relay link. In this paper, an analytical model is presented to derive the buffer-overflow and buffer-underflow probabilities for MSs served by an RN. Several flow control and bandwidth allocation algorithms are then proposed to deal with the buffer overflow/underflow problems. Simulation is then conducted to verify the accuracy of the analytical model and the effectiveness of the proposed algorithms.

[1] ITU-R Rep. M.2134, “Requirements Related to Technical Performance for IMT-Advanced Radio Interface(s),” 2008.
[2] Y. Yang, H. Hu, J. Xu, and G. Mao, “Relay Technologyies for WiMAX and LTE-Advanced Mobile Systems,” IEEE Communications Magazine, pp. 100-105, Oct. 2009.
[3] 3GPP TR 36.814, “Further Advancements for EUTRA: Physical Layer Aspects,” Tech. Spec.n Group Radio Access Network Rel. 9, June 2009.
[4] A. Ghosh, R. Ratasuk, B. Mondal, N. Mangalvendhe, and T. Thomas, “LTE-Advanced: Next-Generation Wireless Broadband Technology,” IEEE Wirelss Communication, vol. 17, no. 3, pp. 10-22, June 2010.
[5] K. Loa, C. C. Wu, S. T. Sheu, Y. Yuan, M. Chion, D. Huo, and L. Xu, “IMT-Advanced Relay Standards,” IEEE Communications Magazine, vol. 48, no. 8, pp. 40-48, Aug. 2010
[6] O. Teyeb, V. V. Phan, B. Raaf, and S. Redana, “Dynamic Relaying in 3GPP LTE-Advanced Networks,” EURASIP Journal on Wireless Communications and Networking, vol. 2009, pp. 1-11, 2009.
[7] S. Parkvall and D. Astely, “The Evolution of LTE towards IMT-Advanced,”IEEE Journal of Communicatins, vol. 4, no. 3, April 2009
[8] 3GPP R2-096471, “DL Flow Control in Un interface,” LG Electronics Inc, RAN2 69#bis, Beijing, China, Apr. 2010..
[9] K. Jagannathan, E. Modiano, L. Zheng, “On the Role of Queue Length Information in Network Control,” – Revision under review, IEEE Transactions on Information Theory.
[10] Q. Zhang and S. A. Kassam, “Finite-state Markov model for Rayleigh fading channels,” IEEE Transaction on Communications, vol. 47, no. 11, pp. 1688–1692, Nov. 1999
[11] M. S. Alouini and A. J. Goldsmith, “Adaptive modulation over Nakagami fading channels,” Journal Wireless Communication, vol. 13, no. 1-2, pp. 119-143, May 2000.
[12] Q. Liu, S. Zhou, and G. B. Giannakis, “Queuing with adaptive modulation and coding over wireless links: cross-layer analysis and design,” IEEE Transactions on Wireless Communications, vol. 4, no. 3, pp. 1142-1153, May 2005.
[13] L. Le and E. Hossain, “Tandem queue models with applications to QoS routing in multihop wireless networks,” IEEE Transations on Mobile Computing, vol. 7, no. 8, pp. 1025-1040, Aug. 2008.
[14] Q. Liu, S. Zhou, and G. B. Giannakis, “Cross-layer scheduling with prescribed QoS guarantees in adaptive wireless networks,” IEEE Journal on Selected Areas in Communications, vol. 23, no. 5, pp. 1056-1066, May 2005.
[15] 3GPP TS 36.216, “E-UTRA: Physical layer for relaying operation,” Tech. Spec.n Group Radio Access Network Rel. 10, March 2011.
[16] F. Hou, S. James, P. H. Ho, X. Shen, “ Performance Analysis of ARQ with Opportunistic Scheduling in IEEE 802.16 Networks,” IEEE Global Telecommucation conference, Nov. 2007.