ICI Aware K-Best MIMO Detection for Fast Fading Channel

The channel variation due to vehicle mobility produces time selective fading among OFDM symbols. An OFDM symbol suffers from inter-carrier interference that severely degrades the performance in high vehicle mobility environment. Traditional sphere decoding and K-Best decoding are suboptimal MIMO detections but still could not suit the high mobility environment well. To solve the problem, an ICI cancellation method combing the ICI aware K-Best decoding is proposed. Under the architecture of ICI cancellation, The proposed method considering both residual ICI and noise power gets better performance than that of the original adaptive K-Best decoding and do not need much complexity. As the analysis showed in the following, the proposed method has a trade off property easily finding how many subcarriers should be taken for ICI cancellation most efficiently.

關鍵字

球體解碼

並列摘要

正交分頻多工（Orthogonal Frequency Division Multiplexing，OFDM）的技術已被廣泛應用在許多通訊系統上。然而在高速移動的環境下，無線傳輸的通道會符合時間選擇通道模型（Time-selective Channel Model），造成載波間的互相干擾（Inter-carrier Interference，ICI），使得載波之間失去正交性，若不補償此效應則會明顯的降低系統的良率。在系統架構很大的情況下，載波干擾消除（ICI Cancellation）是個不可避免的補償措施，然而載波干擾絕大部分都分佈在鄰近的載波上，因此對所有的載波干擾都消除並不是個明智的選擇。 K-Best球體解碼（K-Best Decoding）是一種近乎最佳解的解碼方法。適應性K-Best球體解碼（Adaptive K-Best Decoding）將環境中的雜訊考慮在演算法當中，但在高速移動的環境下良率還是不高。本篇論文中，我們提出和載波干擾相關的K-Best球體解碼（ICI Aware K-Best Decoding），結合載波干擾消除的架構，並將剩餘的載波干擾考慮進演算法中。利用此方法，可以有效的在高速移動環境下提升系統的良率。在所提出的系統架構下，良率的表現會跟載波干擾消除的量的取捨有絕對性的關係，因為剩餘的載波干擾會被用來控制K的大小，影響解碼的準確性。最後我們利用此特性可以輕易的決定出使用硬體最有效率的載波干擾消除的量。

並列關鍵字

K-Best Decoding

參考文獻

[1] Weinstein, S., and Ebert, P., "Data Transmission by

Frequency-Division Multiplexing Using the Discrete

Fourier Transform," IEEE Transactions on

[2] Kwanghoon Kim, and Hyuncheol Park, "A Low Complexity

ICI Cancellation Method for High Mobility OFDM

國際替代計量

ICI Aware K-Best MIMO Detection for Fast Fading Channel

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