於 MIMO-OFDM 之 數 位 訊 號 型 成 波 束 天 線 之 設 計 與 分 析

Abstract

波束成型(digital beamforming)是一個由多根天線產生一個有全向性波束的技術，其目的是為了可以提高訊號的品質消除其他訊號之干擾，並提升在多輸入多輸出 (MIMO) 的傳輸系統效能。 本篇論文提出一個方法來搜尋訊號入射角的角度，此演算法是利用接收端所收到的訊號做能量之分析，藉由偵測到不同角度的能量，來調整波束的角度。另一方面在波束角度，我們利用權重向量來做調整，提升訊號的強度並衰減其他干擾之訊號，即可提升訊號的品質。 在3GPP Long-Term Evolution(LTE) 的系統平台且符合Spatial Channel Model (SCM)所規範的通道模型中模擬。模擬結果指出此演算法和未使用全向性波束的技術效能相比，可發現訊號的強度對效能之影響，提高整體系統的效能。以上皆是應用在多輸入多輸出的傳輸系統平台。

Digital beamforming in MIMO-OFDM system is an efficient way to improve the performance. It emphasized that the signals of interest and minimize interfering signals. Using received signals and controlling the beam pattern is used to steering the direction of maximum gain. In this paper, the estimation of arrival of angle (AOA) is proposed. This method used the correlation power of transmitted signals by searching the maximal quality at received. In addition, it could find an arrival angle on received-end and used weighting vector to adjust angle of beam pattern to steering them. Weighting vector can promote signals of interest quality and improve SINR (Signal Interference Noise Ratio), increasing performance. The simulation platform is 3GPP Long-Term Evolution (LTE) with Spatial Channel Model (SCM) channel. It showed that the proposed algorithm with digital beamforming is better than with the unused digital beamforming system. All of these simulations are in MIMO-OFDM 4×4 platform.