此篇論文提供一個,在有干擾信號的異質網路正交分頻多重接取系統下到達角度的波束成型設計,此方法不需要估測通道參數資訊,也不需要每一根子載波都計算一次波束權重.此方法主要是以特徵分解的方式來建構信號空間給估測角度演算法來偵測角度，使用此法可以減低家庭基站與後端網路連接的過度附載或是延遲. 在估算出接收到的角度後,可使用群集的方法來消除接收端使用者同頻的干擾.群集的概念一開始是在文獻[1]中提出,此篇文獻假設使用者只有單一角度,且在接收端有多用戶偵測器.然而這些假設並不合理,所以我們提出另一種,在沒有多用戶偵測器並考慮多重路徑下的群集方法. 最後電腦模擬分析,將會顯示提出方法是有效的. In this thesis, we proposed an angle of arrival (AOA) based beamforming structure for orthogonal frequency division multiple access (OFDMA)-based Hetnet systems. The proposed scheme has interference resistant capability without the needs in the estimation of the channel parameters and the calculation of beamforming weight vector for each subcarrier in OFDM-based systems. It can also reduce extra burden and delay generated from communication link between the femtocell and the central entity for using beamforming technology. Then, one can also use the obtained AOAs at receivers to group users to reduce the co-channel interference (CCI) among users. The grouping concept appears in [1] which requires a multi-user detection device at the receiver and ignores the influence of multipaths. However, the multi-user detection device may not exist in the receiver and some multipath might cause serious interference effect. In this thesis, another grouping idea is proposed to aim at minimizing the CCI by considering the multipath impact and without multiuser detection device. The simulation results are presented to demonstrate the efficacy of the proposed algorithms.
