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標題: 多服務正交分頻多工系統利用暫存器資訊及服務需求以權重輪流方式做子通道分配
Queueing-Aware Weighted-Round-Robin Subchannel Allocation for Multi-service OFDM Systems
作者: 吳恆毅
Wu, Heng-Yi
關鍵字: QoS;多媒體;multimedia;wireless network;cross-layer category;optimization;fairness;resource management;OFDM;WRR;Queueing control;EF class;無線網路跨層設計;最佳化;公平性;資源分配;正交分頻多工;輪式分配;暫存器控制;加速轉發服務
出版社: 電機工程學系所
引用: [1] C. Y.Wong, R. S. Cheng, and et. al., "Multiuser ofdm with adaptive subcarrier, bit, and power allocation," IEEE J. Select. Areas Commun., pp. 1747-1758, Oct. 1999. [2] R. F. H. Fischer and J. Huber, "A new loading algorithm for discrete multitone transmission," in Proc. IEEE Globecom''96, London, UK, Nov. 1996, pp. 724-728. [3] R. Sonalkar and D. Applegate, "Shannon capacity of frequency-overlapped digital subscriber loop channels," in Proc. IEEE ICC''02, May 2002, pp. 1741-1745. [4] E. R.Grunheid and H. Rohling, "A blockwise loading algorithm for the adaptive modulation technigue in ofdm systems," in Proc. IEEE Vehicular Technology Conference, Oct. 2001, pp. 948-951. [5] B. W. Jianmin Mao, W. Melody Moh, "Pqwrr scheduling algorithm in supporting of di®serv," in Proc. IEEE ICC''01, 2001, pp. 679-684. [6] J. H. Wen, L. C. Yeh, and J. R. Chiou, "Fast switching and fair control of congested ow in broadband networks," IEEE J. Select. Areas Commun., pp. 1315-1326, Oct. 1987. [7] Z. Z. Guanding Yu and et. al., "A novel resource allocation algorithm for real-time services in multiuser ofdm systems," in Proc. IEEE VTC''06, 2006, pp. 1156-1160. [8] K. B. L. Wei Wang, Keun Chul Hwang and S. Bahk, "Resource allocation for heterogeneous services in multiuser ofdm systems," in Proc. IEEE GLOBECOM''04, Nov. 2004, pp. 3478-3481. [9] D. Niyato and E. Hossain, "Queueing analysis of OFDM/TDMA systems," in Proc. IEEE GLOBECOM''05, Nov. 2005, pp. 3712-3716. [10] L. Kleinrock, Queueing Systems Volume 1: Theory, 2nd ed. Wiley, 1975.
當無線通訊慢慢步向下一世代系統時,對於多媒體傳輸在無線環境上提供品質服務目前是一個熱門的題目。然後面對這個問題時,只考慮單層最佳化並無法完全滿足多媒體應用的需求。為了處理此問題,一個裝置著跨層設計的系統是必要的。跨層設計的機制可讓各層的資訊互相交流,利用這些互通的訊息來運作系統而到達一個管理良好的系統。因此在些論文當中,我們提出一個新穎的資源分配系統,其能為多重服務-正交分頻多工系統分配子通道並且控制暫存器的容量。此系統主要包括兩個主要的成員:權重輪式管理器以及類交換器的子通道分配器。而權重輪式管理器主要是利用可送速率及暫存器容量來調整權重,藉此服務速率、暫存器容量的變化及在傳統系統中不公平的資源分配的情況可以獲得改善及控制。此外,類交換器的子通道分配器是以隨機的模式來指派子通道給特定的串流。而此系統其中一個特色是能穩定控制暫存器的容量,而已以減少溢流的情況。 依據Little定律,暫存器延遲可被限制在一個範圍內。因此對於EF階級的串流在延遲限制上有很大的幫助。加上適應性調變促使系統在頻寬的使用更加有效率。在模擬結果中可以顯示此系統在暫存器及公平性控制上的能力,經由模擬結果證明系統的可行性。

As we move toward the next generation wireless communication systems, providing the quality of service (QoS) to multimedia transmission in the wireless network is an attracted intensive research. To meet this problem, only considering the single-layer scenario with the separate optimal solutions to each layer does not provide adequate supports for multimedia applications in crowded wireless networks. To cope with this job, devising a system model with cross-layer categories is necessary. Certain layered strategies can be implemented simultaneously in several layers and, hence, the in-depth understanding and comparative evaluation of those strategies through the negotiation between layers can lead into a well-handled system. In this dissertation, a novel resource allocation algorithm is proposed to allocate subchannels and control the queueing capacity in multi-service orthogonal frequency division multiplexing (OFDM) systems. By decomposing this algorithm into two components, namely WRR scheduler and switch-based subchannel allocator, efficient resource management is realized. Specifically, the number of subchannels to be assigned to each stream is first determined by WRR scheduler, which is founded on weighted round robin (WRR) with weight modification. Such a weight modification adapts to the service required rate and queueing variation and tackles with the unfairness inherent in conventional resource allocation mechanisms as possible. Secondly, the responsibility of the switch-based subchannel allocator is to assign subchannels with a specifically probabilistic distribution for streams. One distinguishing feature of the proposed approach is the ability of maintaining the queueing length of streams. This feature can help guarantee the delay within a bound according to Little's law and can benefit delay constraint traffic for Expedited Forwarding (EF) class services. In addition, the proposed mechanism is combined with adaptive modulation to make more efficient utilization of subchannels. The proposed mechanism is validated through simulation. The simulation results have shown the better capability of maintaining queueing length and the fairness that can be achieved by the proposed mechanism.
其他識別: U0005-2201200714012900
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