基於濾波器組多載波系統之創新多載波傳收機設計

Abstract

近年來，由於智慧型手機以及穿戴式裝置的快速發展，當今行動通訊系統所需容納的用戶數量正在不斷的快速增加。在第四代長程演進(Long Term Evolution)行動通訊系統中，其採用正交分頻多工(Orthogonal Frequency Division Multiplexing)技術，利用快速傅立葉轉換(Fast Fourier Transform)即可實現訊號調變。然而，該簡單的調變方式卻會造成各個子載波(Subcarrier)在頻域上會有嚴重的能量分散特性，以至於在考量大量用戶共存的系統時，其可能會面臨嚴重的同步與頻譜存取的問題。本論文設計了一個基於濾波器組多載波(Filter Bank Multicarrier)系統之創新多載波傳輸系統架構，其提供了一個系統化的調變方式以及收斂的子載波波形，讓通訊系統可以更有效的處理多用戶共存的議題。 為了得到良好的通訊品質，接收端在進行訊號解調之前，需要先行偵測所在環境之通道資訊，以利後續通道等化的作業。本論文亦基於所提出之創新架構設計適用的通道估測演算法，藉由特定規則排列的嚮導訊號(Pilot Signals)，系統可以進行通道估測，並將所測得之資訊作為通道等化的依據，提升訊號解調的品質。

In the recent years, due to the emergence of smart phones and wearable devices, the number of users inside the communication system has increased faster and faster. In the 4th generation LTE mobile system, the modulated signal can be implemented very easily by the fast Fourier transform. However, this simple modulation method will lead to the energy spreading issue over each subchannels. As the number of users increasing, it will be very difficult to deal with the multi-users synchronization and spectrum allocation. In this thesis, we purposed a novel multicarrier transceiver which was based on the FBMC technique. The purposed system has a more compact subcarrier pulse shape, which can make the communication system more robust to handle the multi-users issues. In order to ensure the quality of the transmission, the receiver needs to estimate the channel state information. This thesis designed two pilot based channel estimation method for the purposed novel multicarrier system. Using the pilot signals, we can estimate the wireless channel and utilize the estimated channel information to enhance the quality of the demodulated signals.