V-BLAST接收機在平坦MIMO衰落通道中 錯誤傳遞性能之評估

Error-Propagation Performance Evaluation of V-BLAST Receiver for Flat MIMO Fading Channels

張棋皓(Chi-Hao Chang)

指導教授 ： 鍾日龍

中原大學/工學院/電子工程研究所/碩士(2008年)

https://doi.org/10.6840/cycu200800470

摘要

在現今的無線通訊環境中，利用多根傳送與多根接收天線的多重輸出輸入系統(MIMO system)，來使無線通訊系統的資訊容量有顯著提昇的方法目前已廣為我們所知。而其中一種有名的多輸出多輸入技術，垂直貝爾實驗室階層式時空(V-BLAST)結構，就是應用此種多根天線優點的無線通訊架構。
雖然對於V-BLAST的接收機來說，純理論的蒙地卡羅模擬結果已被良好完整的研究文件所提出，但系統效能的理論邊界值仍有需要被快速計算。在這篇論文裡，我們主要針對一個使用最小均方誤差(MMSE)演算法的V-BLAST接收機進行錯誤效能上的研究。首先根據一個考量串流間干擾的高斯近似法，如同高斯分佈一樣，我們先對靜態通道推導出V-BLAST的MMSE接收機的效能下限。除此之外，我們推導的過程中另外還使用了最佳的排列式偵測演算法，前一個符號可以被正確的估計出來並且用來偵測下一個階層的符號。然而，估測的過程中實際上並不是這麼的完美，因此，我們將實際可能的誤差狀況通通考慮進來，推導有誤差情形下的接收機錯誤效能。接下來，封閉型的效能公式可以藉由整體通道的實現平均而來，於是，平坦衰落通道(flat fading channel)的效能也可由此得到。而透過電腦的模擬分析可以證明，模擬的結果充分地與理論符合貼近。最後，我們得到一個結論，就是經由推導論證的效能公式可以對V-BLAST的系統效能提出一個快速的計算方法。

關鍵字

多重輸出輸入 ； 錯誤遞迴 ； 高斯近似概算 ； 衰落通道 ； V-BLAST

並列摘要

It is well known that employing multiple transmit and receive antennas (MIMO) can increase information capacity of wireless communication systems significantly. Wireless communication architecture, such as the vertical BLAST (Bell Laboratories Layered Space-Time) is one of famous MIMO techniques which can exploit the capacity advantage of multiple antennas. Although pure Monte-Carlo simulation results of the V-BLAST receiver has been well documented, the theoretical bound and practical performance is also required for quick evaluating system performance. In this paper, we investigate the error performance lower bound of the minimum-mean-square-error (MMSE) V-BLAST receiver. First, with the Gaussian approximation (GA) technique which regards the inter-stream interference as Gaussian distributed, we first derive the lower bound of the MMSE V-BLAST for the static channel. The derivation work is also assuming that the optimal ordering algorithm and correct previous detected symbols to the next detecting layer. However the detection procedure is not always perfect. Error propagation between different detected layers will degrade the system performance greatly. So, we consider the error propagation effect and take one into account to derive the error probabilities of detected sub-stream. Next, the closed-form performance formula is averaged over an ensemble of channel realization, and then the final performance for the flat fading channels is obtained. Computer simulation is included to demonstrate that the theoretical and simulated results coincide well. Finally, we conclude that the derived result can serve the method for quickly evaluating the V-BLAST system performance.

並列關鍵字

Gaussian approximation (GA) ； multiple- input multiple-output (MIMO) ； Fading channels ； V-BLAST

參考文獻

[1]V. Tarokh, N. Seshadri, and A. R. Calderbank, “Space-time codes for high data rate wireless communication : Performance criterion and code construction,” IEEE Trans. Inform. Theory, vol. 44, pp. 744-765, Mar, 1998.

[2] V. Tarokh, N. Seshadri, and A. R. Calderbank, “Space-time codes for high data rate wireless communication : Performance criterion in the presence of channel errors, mobility, and multiple paths,” IEEE Trans Commun, vol. 47, pp. 199-207, Mar, 1999.

[3] G. D. Golden, C. J. Foschini, R. A. Valenzuela and P. W. Wolniansky, “V-BLAST: An architecture for realizing very high data rates over the rich-scattering wireless channel,” Signals, Systems, and Electronics, Oct, 1998.

[4] G. Foschini, “Layered space-time architecture for wireless communication in a fading environment when using multi-element antennas,” Bell Labs Technical Journal, pp. 41-59, Autumn, 1996.

[5] 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, pp. 14-16, Jan, 1999.