運用自適應濾波器演算法 補償2× 2多天線輸入多天線輸出60-GHz 光載微波無線系統之非線性失真

Abstract

隨著手持式行動裝置的普及和無線通訊技術的蓬勃發展，全球行動網路的每月數據流量日益增多，如圖1.1.1所示，人們對於現今多媒體影音傳輸與互動式多媒體應用以及雲端儲存技術上的需求大量增加，無線網路有著可移動性且覆蓋率廣泛的優點，用戶使用網路服務時不會再受到地區的限制，為了滿足多媒體業務和雲端服務的無線網路流量爆炸性需求，無線通訊系統也必須導入更新穎的通訊技術，為了追求高資料傳輸效率，現有的頻寬已經不能滿足需求，進而帶動毫米波通訊的發展。而在57-64GHz(V-band)間有著7GHz的免認證連續頻帶可供使用，然而在60GHz訊號在傳統電纜與無線空間的傳輸衰減率極高。因此光載微波系統是一種可行的方案，結合光纖通訊與60GHz無線通訊系統系統被提出，為了增加頻譜使用效率，多天線輸入多天線輸出技術也被應用在此概念中。 本文將採用Volterra非線性補償技術結合多天線輸入多天線輸出技術，去探討光載微波系統中的非線性效應，運用Volterra非線性補償技術於兩種架構，包括子載波多工系統利用混頻器降頻以及功率偵測器降頻系統，利用Volterra非線性補償技術可以提高遠程天線單元(Remote Antenna Units, RAUs)輸出功率，由於60GHz訊號無線傳輸的高損耗性，遠程天線單元有更大的功率的話，能傳輸更遠的無線距離，在功率偵測器降頻系統中，雖然可以簡化接收端的架構，卻會有二階非線性失真的產生，可以利用Volterra非線性補償技術可以提升訊號品質。

With the popularity of handheld mobile devices and the rapid development of wireless communication technology, the global mobile network data is increasing. There has been a significant increase in demand for today's multimedia audio and video and interactive multimedia applications and cloud storage. In order to meet the multimedia business and cloud storage services, wireless network traffic explosive demand, wireless communication systems must also be developed with more innovative technology. The existing bandwidth has been unable to meet the demand for high data rate, and then drive the development of millimeter wave communication. The free-license V-band (57-64 GHz) is able to provide considerably more bandwidth. However, V-band wireless transmission is limited by high propagation loss in air. Radio-over-fiber (RoF) system combines with fiber communication and V-band wireless communication. Moreover, multi-input multi-output (MIMO) technology can also promote spectral efficiency with transmitting multiple signals within the same bandwidth. This paper will use Volterra nonlinear compensation technology combined with multi-antenna input multi-antenna output technology and discuss the nonlinear effect in the 60GHz RoF system. The Volterra nonlinear compensation technique is used in two architectures, including subcarrier multiprocessing systems using mixer down-conversion and power detector down-conversion. The use of Volterra nonlinear compensation technology can improve the remote antenna unit output power. If the remote antenna unit has more power, then can transmit farther wireless distance. In the power detector down-conversion system, the cost of the receiver can be simplified ,but there will be nonlinear distortion generation. The use of Volterra nonlinear compensation technology can improve the signal performance.