正交分頻多工存取中繼網路之比例式公平排程

Proportional fair scheduling has been extensively studied. Early works considered single-carrier situations. As OFDMA being adopted in many modern broadband wireless systems, multi-carrier scheduling becomes a hot topic. Rather than directly applying a single-carrier algorithm to each carrier in turn independently, by jointly considering and scheduling the all channel resources, better system utilization may be achieved. In this work, we take IEEE 802.16j OFDMA multihop relay network under transparent relaying mode as our reference system model. We consider a high-level multi-carrier proportional fair scheduling problem under infinitely backlogged assumption. To better utilize the system resources, three data transmission schemes are considered: direct transmission, relay transmission, and cooperative transmission. The BS gathers SINRs of each link and is responsible for assigning time, frequency, and transmission scheme for each user in every frame. The basic goal is to reach proportional fairness and we want to further maximize system throughput, which involves very high complexity. An time-efficient scheduling algorithm is therefore desired at run-time. We proposed four algorithms and compare their performance through extensive simulations. Analysis of the behaviors of our proposed algorithms is also presented.

關鍵字

比例式排程；協同式資料傳輸

並列摘要

比例式公平排程(Proportional fair scheduling)已經受到廣泛的研究。早期研究的是單載子(single-carrier)系統，而在正交分頻多工存取(OFDMA)在許多近代的無線寬頻系統上被採用時，多載子(multi-carrier)的排程成為了研究的焦點。不同於直接將適用於單載子系統的演算法一一套用在每個載子上，當能同時考慮對所有的頻道排程時，能更充份有效地使用系統資源。在本次研究，我們的參考環境是IEEE所提出的802.16j正交分頻多工存取多躍中繼網路(multihop relay network)，並且假定其運做在透空中繼模式(transparent relaying mode)底下。我們考慮一個高階的多載子比例式公平排程的問題，假定所有的用戶永遠待排程的資料。為了更善用系統資源，考慮三種資料傳輸機制，分別是直接傳輸(direct transmission)、中繼傳輸(relay transmission)，以及協同式傳輸(cooperative transmission)。基地台獲取各連線的SINR值，並且負責在每一個傳訊框(frame)中，為使用者指定資料收送的時間、所使用的頻道，以及所採用的傳輸機制。基本目標是想達成比例式公平排程的要求，並且進一步想將系統傳輸量最大化。要解決這樣的問題，複雜度相當高，因此為了要能在系統運做時使用，勢必需要有執行時間上很有效率的排程演算法。我們提出了四種演算法，並且透過模擬實驗來比較了他們的結果，也同時對每種演算法的行為模式做了一些分析。

並列關鍵字

proportional-fair scheduling ； cooperative transmission

參考文獻

[1] H. Yin and S. Alamouti, “Ofdma: A broadband wireless access technology,” pp. 1–4,

March 2006.

[2] L. Tassiulas, R. Tassiulas, and A. Ephremides, “Dynamic server allocation to parallel queues with randomly varying connectivity,” IEEE Transactions on Information Theory, vol. 39, pp. 466–478, 1993.

[3] L. Tassiulas and A. Ephremides, “Stability properties of constrained queueing systems and scheduling policies for maximum throughput in multihop radio networks,” IEEE Trans. Automat. Contr., vol. 37, pp. 1936–1948, Dec. 1992.

[5] “Multiuser diversity in wireless networks.” http://www.eecs.berkely.edu/ dtse/stanford416.ps, 2002.

國際替代計量

正交分頻多工存取中繼網路之比例式公平排程

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