區域多點分散式服務為點對多點的固定式無線寬頻存取服務，採用蜂巢式系統來提供高速的服務，如：寬頻、影像、音訊、數據等服務，免除以往使用纜線及其他有線方式佈置之費用，並適合用於『最後一哩』等無線接取技術。然而現今多天線傳輸技術可有效地提升系統的效能與傳輸速度，多天線傳輸技術主要可分成三大種類：波束形成、時空碼、空間多工，其中波束形成對抗干擾有顯著的成效；時空碼具有多樣性的能力，以對抗衰落的通道來提升效能，使位元錯誤率降低；空間多工可大幅提供資料傳輸速率。在本論文中，我們將使用各種多天線傳輸技術，並於蜂巢式系統架構下，以電腦模擬來分析各種多天線傳輸技術方法在此架構下的位元錯誤率效能與頻譜效益。 LMDS (Local Multipoint Distribution Service) is the point to multi-point fixed wireless broadband access system and adopts cellular system to provide high-speed service such as: broadband access, video, message, data, etc. LMDS reduces the cost of traditional connection which uses coaxial cable or other wired method and is suitable for “Last-Mile “wireless access technique. Today multiple antennas transmission technique provides better system performance and higher data rate effectively. Multiple antennas transmission technique includes Beamforming, Space Time Code, and Spatial Multiplexing. Beamforming provides resistance to interference obviously, Space Time Code improves the error performance against multi-path fading channel, and Spatial Multiplexing provides higher data rate. In this thesis, we will make use of some multiple antennas transmission technique to analysis the bit error rate performance and spectrum efficiency of LMDS cellular system by computer simulation.
