在無線通訊系統快速的發展下，頻寬效益和通訊品質成為了熱門討論的議題。無線通訊有許多的難題，如多重路徑失真、多重路徑干擾。智慧型天線是一種使用多根天線組成的天線陣列。智慧型天線會針對接收訊號的角度成可調適性的波束，在想要訊號經過後會維持一定的增益，也會抑制干擾訊號，束波形成器即是建立在智慧型天線技術的基礎上。 分碼多重存取在第二代與第三代無線通訊系統被認為是引人注目的多重存取結構。在分碼多重存取通訊系統裡，不同的干擾消除技術被提出，如最小變異無失真響應形成器、最小變異數形成器和廣義旁波帶消除器。束波形成器的技術允許天線陣列在空間域下形成特殊的形狀而且是可調勢性的，這種特性使得訊號接收端可以考慮到傳輸環境的變動做調整。 在這篇論文裡，我們主要研究關於強健式波束形成器的效能，針對強健式波束形成器在不同環境下接收訊號，分析輸出訊號干擾雜訊比，更進一步，波束形成器將被引進分碼多重存取通訊系統做效能的分析。 In the rapid development of wireless communication system, the bandwidth efficiency and communication quality have become an interesting issue for researchers. There are a lot of difficulties such as multipath fading and multiple-access interference (MAI) and etc. Smart Antennas is the technology that use a fix set of antennal elements in an array. The signals from these antennal elements are combined to form an adaptive beam pattern that can keep the desired signal and suppress the interference. Beamforming is based on the Smart Antennas technique. The schemes about Code-Division Multiple Access (CDMA) have been considered as attractive multiple access schemes in both second-generation (2G) and third-generation (3G) wireless systems. There are various interference-cancellation techniques have been used in CDMA communication systems such as Minimum Variance Distortionless Response Beamforming (MVDR), Linearly Constrained Minimum Variance Beamforming (LCMV) and Generalized Sidelobe Canceller (GSC) structure. Beamforming technique allows antennal arrays to form the particular shape in spatial domain and to adaptive filtering allows a receiver to accommodate changes of the propagation environment. In this paper, the GSC based robust beamforming is proposed. In this paper, we investigated the effect of correlation on the performance of the robust beamforming. The analysis yielded an explicit expression for the Signal to Interference plus Noise Ratio (SINR) at the output of robust beamforming in terms of the different situations. Further, the robust beamforming would apply to CDMA communication system to evaluate the system performance.
