多天線輸入多天線輸出技術應用於正交多頻分工之60GHz光載微波無線訊號系統

Abstract

隨著互動式多媒體的發展，許多無線網路服務不斷的推陳出新，對於無線傳輸速度的要求也逐漸升高。為了提高傳輸速度，將載波頻率提高到擁有7GHz免授權頻段的60GHz頻段，由於60GHz的微波訊號在空氣中有非常嚴重的衰減，因此我們使用光載微波無線訊號來解決這個問題。在本實驗室過去的研究中，對於60GHz無線網路在實作上所存在的一些問題已經做了許多分析及討論。搭配空間多功的多輸入多輸出系統，更可以提供一個寬頻、覆蓋範圍廣及機動性兼具的服務。 在此篇論文中，實現多輸入多輸出系統技術，提高頻譜使用效率，使用等化器及訓練符元的設計，解決I/Q不平衡對OFDM訊號之影響，並探討空間分布所造成的問題。我們成功的傳輸60GHz頻段上7GHz免授權頻寬的OFDM訊號，傳輸速度最高達到81.54Gbps，並在經過50公里的單模光纖和3.5公尺的無線傳輸以後，訊號品質幾乎沒有改變。

With the rapid growth of interactive multimedia services, the speed of data transmission must improve and the demand for the wireless bandwidth is increasing. For increasing data transmission, we raise the carrier frequency to 60 GHz which can offer 7 GHz unlicensed band. However, because of the serious propagation loss of 60GHz RF signal, the radio-over-fiber system is proposed to reduce the overall cost. In the past years, our group have done a lot of research on the 60GHz system. With MIMO technology, the system can promise candidate to provide broadband service, wide coverage, and mobility In this thesis, 2x2 MIMO technique is realized. With equalizer and training symbol design, we can solve the I/Q imbalance problem. Moreover, we also focus on the problems from spatial distribution. We experimentally demonstrate 81.54Gbps OFDM signal transmission within 7GHz license-free bandwidth at 60GHz band. The power penalty is negligible after transmission over 50km single mode fiber and 3.5m wireless distance.