在第四代行動通訊(the 4th Generation of mobile communication system, 4G)中，通訊標準以正交分頻多工技術(Orthogonal Frequency Division Multiplexing, OFDM)為主，其優點有：有效對抗頻率選擇性衰減、抗碼間干擾能力強、實現簡單等，而缺點為高頻外(out-of-band, OOB)溢出。
　　隨著物聯網的興起，第五代行動通訊(the 5th Generation of mobile communication system, 5G)的目標是：高資料傳輸速率、低延遲、高頻譜效率和大規模裝置連接。然而，廣義分頻多工(Generalized Frequency Division Multiplexing, GFDM)是一種很有前途的多載波方案，它有著低頻外溢出的特性，可以靈活處理第五代行動通訊的各種不同應用場景。
　　但是，由於廣義分頻多工系統中所應用的濾波器會產生自干擾，包含子符元間干擾(Inter-symbol Interference, ISI)和子載波間干擾(Inter-Carrier-Interference, ICI)，使位元錯誤率(Bit error rate, BER)相較正交分頻多工技術來的差。
在本篇論文中，我們將各種不同的預處理及後處理添加到傳統GFDM架構中，消除了自干擾的影響，進而討論GFDM對於不同改良方法的BER、峰均值功率比(Peak-to-Average Power Ratio, PAPR)、功率頻譜密度(power spectral density, PSD)，以及複雜度。
BER效能模擬將會在GFDM系統之不同濾波器滾降係數和不同通道模型的環境下進行，分析每一種方法在不同的情況下會有什麼影響。

In the 4th Generation of mobile communication system (4G), the communication standard is based on Orthogonal Frequency Division Multiplexing (OFDM), which has the following advantages: effective against frequency selectivity attenuation, strong ability to resist inter-symbol interference, simple implementation, etc., but the disadvantage is high out-of-band (OOB) leakage.
With the rise of the Internet of Things, the goals of the 5th Generation of mobile communication system (5G) are: high data transmission rate, low latency, high spectral efficiency, and large-scale device connections. However, Generalized Frequency Division Multiplexing (GFDM) is a promising multi-carrier scheme. It has the characteristics of low OOB leakage and can flexibly handle various scenarios of the 5th Generation of mobile communication system (5G).
In this paper, we add a variety of pre-processing and post-processing to the original GFDM architecture to eliminate the influence of self-interference and then discuss the bit error rate (BER), peak-to-average power ratio (PAPR), power spectral density (PSD), and complexity of GFDM for different improved methods.
The BER performance simulation will be performed in different roll-off factors of filter and different channel models to analyze the impact of each method under different situations.

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