應用於訊號到達方向估測及波束成型之高自由度間距限制天線陣列架構

Abstract

非均勻線性陣列(Nonuniform Linear Array)架構是一種能夠有效增加智慧型天線陣列中隱含自由度的技術，目的是為了能夠偵測到比感測器數目更多的入射信號。這篇論文提出了一種基於間距限制的非均勻線性陣列架構，與嵌套式陣列(Nested Array)和傳統的均勻線性陣列(Uniform Linear Array)相比之下，其在自由度的提升方面擁有顯著的改善。此外在提出的天線陣列中，感測器的位置可以有解析解，這成功地克服了最小冗餘度陣列(Minimum Redundancy Array)的限制。在提出的架構中，我們利用改寫陣列流形矩陣以及應用空間平滑(Spatial Smoothing)技術修改相關矩陣來證實運用這種天線陣列架構於增強自由度的可行性。 我們應用提出的架構於訊號到達方向估測以及接收波束成型上。模擬結果顯示即使入射訊號個數大於接收端天線的個數，我們依然能夠偵測與估計出入射信號來源的方向。此外，提出的天線陣列在訊號到達方向估測的均方根誤差(RMSE)結果以及接收波束成型的訊號與干擾雜訊比(SINR)結果上都擁有優異的效能。

Nonuniform linear array configuration is an effective technique for increasing obtainable degrees of freedom (DOF) in smart antenna arrays, in order to detect more incoming sources than the number of physical sensors. This thesis proposes a novel nonuniform linear array configuration based on a spacing constraint to provide great enhancement of degrees of freedom, which has significant improvement compared with the nested array and the traditional uniform linear array. Besides, the sensor locations in the proposed array can be derived as a closed-form expression, which successfully overcomes the limitation of the minimum redundancy array. In the proposed structure, we rewrite the array manifold matrix and apply the spatial smoothing technique to modifying the received correlation matrix in order to confirm the availability of the DOF enhancement owing to the proposed array structure. We apply the proposed structure to the applications of DOA estimation and receive beamforming, the simulation results shows that we are able to detect and estimate the direction of incoming sources even when the number of incident signals is larger than the number of antenna elements at the receiver. Moreover, the proposed array has high performance, in terms of the root mean square error (RMSE) results of the DOA estimation, and signal to interference-plus-noise ratio (SINR) of the receive beamforming.