多輸入多輸出之最大相似接收器系統下利用RBIR實現鍊路至系統的映射研究

Study On Link-to-system Mapping For MIMO ML Receivers Based On RBIR Metrics

丁威佑(Ding Wei-You)

指導教授 ： 邱茂清

國立中正大學/工學院/通訊工程學系/碩士(2012年)

摘要

為了降低系統模擬的複雜度，鍊路至系統的映射(link-to-system mapping)被廣泛的運用以便預估系統的效能，同時此模型更可進一步應用在實際的系統上，例如：用以改善適應性鍊路(link adaptation)的正確性以及更有效的做無線資源管理(radio-resource-management)。傳統上所使用的訊雜比平均已不足以用來描述衰退通道(fading channel)的特性，因為在變動的衰退通道下，一樣的訊雜比平均值可能會導致錯誤率的表現有很大的差異。
本文主要探討一個以互消息量為基準的映射模型，其中包含了可以被分離的兩個模型，調變模型及編碼模型。調變模型針對每個接收到的符號將訊雜比轉換為互消息量；而編碼模型則將每個編碼方塊的平均互消息量轉換為錯誤率。與現行的模型相比，以互消息量為基準的模型在計算上較為簡單且在預估系統效能方面更為準確，並且更容易應用在混合式的調變系統下。但是，不幸的是我們發現在[2]中存在一些錯誤，這些錯誤會導致估算互消息時的錯誤，也進一步影響預估系統效能的準確性。因此，在本文中我們主要將證明這些錯誤的存在且修正它們，另外，也提供一個更準確的互消息估算方法。

關鍵字

多輸入多輸出 ； 鍊路至系統的映射

並列摘要

Link-to-system mapping is widely used in system evaluations to reduce the simulation complexity. It is also important in practical systems for improving the accuracy of the link adaptation and the efficiency of radio-resource-management. Conventional methods using linear average of signal-to-noise-ratios (SNR) may not work well over fading channels, since the same SNR may lead to drastic error rate due to different fading characteristics.
This paper discusses a mutual-information-based (MI-based) link-to-system mapping, which contains separate modulation and coding models. The modulation model maps the symbol-by-symbol received SNR to the mutual information and takes the arithmetic average of mutual information. The coding model maps the averaged mutual information to decoding performance for each coding block. Compared with the existing methods, the MI-model is more accurate and easier to apply to mixed-modulation cases. Unfortunately, in a standard contribution [2], we found some errors which lead to a completely wrong estimation of mutual information. In this paper, we aim to correct the errors found in [2] and provide a more accurate estimation of mutual information.

並列關鍵字

MIMO ； link-to-system mapping ； Received Bit Information Rate (RBIR)

參考文獻

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[11] S. M. Alamouti, “A simple transmit diversity technique for wireless communications,” IEEE Journal on Selected Areas in Communications, Vol.16, no.8, pp.1451-1458, Oct 1998.

[12] G. D. Golden, C. J. Foschini, R. A. Valenzuela and P. W. Wolniansky, “Detection algorithm and initial laboratory results using V-BLAST space-time communication architecture,” Electronics Letters, Vol.35, no.1, pp.14-16, 7 Jan 1999.

[14] P. W. Wolniansky, G. J. Foschini, G. D. Golden and R. A. Valenzuela, “V-BLAST: an architecture for realizing very high data rates over the rich-scattering wireless channel,” in Proc. URSI ISSSE, pp.295-300, Sept 1998.