室內毫米波空-時通道模型之研發

Abstract

毫米波頻段將於未來5G行動通訊被廣泛應用，由於毫米波波長短，導致天線有效孔徑面積小，因此能量路徑損失將變大，且毫米波穿透性差，易受室內環境中障礙物所遮蔽，導致通訊品質變差，為了克服此問題，系統將會採用波束成形(Beamforming)以及波束切換(Beam Switching)等技術，因此透過建立室內環境無線電空-時通道，藉此了解毫米波於室內環境的空時特性。

ㄧ般而言，當天線之波束寬越寬時，將較無對準的問題，涵蓋率較廣，但能量將較無法集中，將無法將傳輸距離提升，系統訊雜比(SNR)較差，且會有多重路徑干擾，導致資料傳輸率(data rate)下降，然而當天線之波束寬越窄時，能量將較能集中，以提升其傳輸距離，減少多重路徑干擾，但涵蓋率將會變低，須克服對準的問題，因此天線之波束寬將於涵蓋率及多重路徑干擾之間相互折衷。

因此本論文將先討論現有應用於室內環境毫米波空時通道模型，分析其優缺點，並加以修正，並加入ㄧ些散射體進行討論，並提出適合波束選擇(Beam Selection)以及波束切換(Beam Switch)技術之應用之通道模型，並探討於不同房間大小及AP擺放位置，不同波束選擇下對其覆蓋率的影響，可做為室內毫米波無線通訊系統的參考數據。

The millimeter-wave band will be widely used in the future 5G mobile communication, because the millimeter wave wavelength is short, resulting in the antenna effective apeture is small, so the path loss will become larger, and millimeter wave penetration is not good, in order to overcome this problem, the system will use beamforming and beam switching technique, building a spatial- temporal channel model can make us understand the millimeter wave in the indoor environment of the space-time characteristics.

In general, when the beam width of the antenna is wider, the coverage of the environment would be wider, but the energy will be less concentrated. The propagation distance will be short, the lower signal to noise ratio (SNR) and multipath interference will result in data rate decreased, but when the antenna beam width is narrow, the energy will be not only more concentrated to enhance its propagation distance but also reduce multipath interference. However the coverage will be lower. In order to overcome the problem of alignment, the beam width of the antenna will trade off between the coverage and multipath interference problem.

This paper will discuss the millimeter-wave spatial-temproal channel model for indoor environment, and analyze its advantages and disadvantages, and would improve it, and discuss some scatterers effect for indoor environment and propose suitable for beam selection and beam switching technology application, which can be used as reference data for indoor millimeter-wave wireless communication system.