臺灣博碩士論文加值系統

廣義分頻多工是次世代無線通訊系統頗具前途的波型候選人之一。然而，如何實踐廣義分頻多工的通道估測始終是一大挑戰，因其系統本身載波間通常為非正交而存在干擾。本論文首先提出一個基於預編碼器的領航符號插入架構，適用於廣泛的調變矩陣，包括了廣義分頻多工矩陣，並且針對預編碼器推導出了在接收端對應之最小均方誤差估計器。基於此架構我們進一步提出了一個可在接收端消除估測干擾之預編碼器，其透過了讓傳送訊號在頻域上的若干頻率點形成固定領航符號，進而消除若干頻率點上因資料符號之隨機性而產生的變動。模擬結果顯示我們提出的預編碼器相較於傳統的領航符號散佈方法，降低了通道估測的均方誤差與訊雜較高時的符號錯誤率

Generalized frequency division multiplexing (GFDM) is a promising candidate waveform for next-generation wireless communication systems. However, channel estimation is still challenging for GFDM due to its inherent interference. In this paper, we formulate a pilot-insertion framework based on a precoder design for block-based systems including GFDM and derive its linear minimum mean square error (LMMSE) channel estimator. We propose a solution for the precoder to achieve interference precancellation by generating the pilots at several tramsmit frequency bins and eliminating the randomness at such frequency bins due to data symbols. Numerical results demonstrate that the proposed method reduces the channel estimation mean square error and high signal-to-noise ratio (SNR) symbol error rate (SER), compared to conventional pilots scattering methods.

誌謝 ii
摘要 iii
Abstract iv
1 Introduction 1
2 System Model for GFDM Channel Estimation 5
2.1 GFDM System Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.1 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.2 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 OFDM Channel Estimation . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Proposed Methods 9
3.1 The Problem of Channel Estimation in GFDM . . . . . . . . . . . . . . . 9
3.2 Pilot-insertion Framework . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2.1 Precoder Design . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2.2 LMMSE Channel Estimation . . . . . . . . . . . . . . . . . . . . 13
3.3 Interference-canceled Pilot Insertion Precoder . . . . . . . . . . . . . . . 15
3.3.1 Pilot-stone Condition . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3.2 Proposed Procedure for The Precoder Design . . . . . . . . . . . 15
3.4 Index Choice for GFDM . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.4.1 Pilot-stones Indexes . . . . . . . . . . . . . . . . . . . . . . . . 18
3.4.2 Pilot-holes and Data-holes Indexes . . . . . . . . . . . . . . . . . 18
3.5 IFPI-GFDM Channel Estimation . . . . . . . . . . . . . . . . . . . . . . 20
3.5.1 The Frequency-Domain Implementation for GFDM . . . . . . . . 20
3.5.2 The Modulation Matrix for IFPI-GFDM . . . . . . . . . . . . . . 21
3.5.3 The Proposed Pilot-insertion Precoder for IFPI-GFDM . . . . . . 22
4 Simulation Results 24
4.1 Parameter Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.1.1 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . . . 25
5 Conclusion 28
Bibliography 30
A Power Spectral Density 33
A.1 For Original GFDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
A.2 For General GFDM Precoder “A” . . . . . . . . . . . . . . . . . . . . . 36

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