| DC 欄位 |
值 |
語言 |
| DC.contributor | 通訊工程學系 | zh_TW |
| DC.creator | 葉寰融 | zh_TW |
| DC.creator | Huan-Jung Yeh | en_US |
| dc.date.accessioned | 2012-8-10T07:39:07Z | |
| dc.date.available | 2012-8-10T07:39:07Z | |
| dc.date.issued | 2012 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:444/thesis/view_etd.asp?URN=995203052 | |
| dc.contributor.department | 通訊工程學系 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | 近年來，我們對於移動無線通訊中的傳輸量日益漸增。單載波分頻存取技術(SC-FDMA)由於它的傳輸功率效率可以有效的降低峰值平均功率比(PAPR)。本質上來說，單載波分頻存取(SC-FDMA)系統的傳輸架構類似於正交分頻多工存(OFDMA)系統，除了單載波分頻多工為在正交分頻多工系統前加上離散傅立葉轉換前置編碼的系統。因此，單載波分頻存取適用於上鏈多重存取技術，尤其對於下世代的無線通訊系統中電池的壽命是很重要的一環。在3GPP 通訊，長程演進（LTE）規格已將單載波分頻多重存取制定成下一代行動通訊系統上鏈傳輸之多重存取技術。
在本論文中我們提出兩種最小均方誤差(MMSE)等化器對於在長程演進上鏈單載波分頻多工系統都普勒效應(Doppler effect)所產生之子載波間干擾(ICI)去做補償。其中一種為多用戶最小均方誤差等化器(MU MMSE equalizer)，另一種為單一用戶最小均方誤差等化器(SU MMSE equalizer)。雖然多用戶最小均方誤差等化器可以達到較好的系統效能，但相對它需要更高的計算複雜度。相反的，單一用戶最小均方誤差等化器儘管在位元錯誤率會較差，但由於它利用子載波間干擾矩陣(ICI matrix)之帶限(band-limited)架構有效的降低計算複雜度。除此之外，我們提出一子載波間干擾消除與單一用戶最小均方誤差等化器結合並利用迭代(iterative)的方式，更進一步增進了位元錯誤率之效能。模擬結果也顯示出我們所提出方法可以有效的改善系統效能。在長程演進上鏈單載波分頻多工系統中，使用者之間的資源分配在移動的環境下會對位元錯誤率之效能造成影響。我們提出一個新的方法利用上層(upper-layer)的區塊資源分配(chunk resource allocation)有效的減緩子載波間干擾的影響。首先，我們根據使用者的子載波映射矩陣(subcarrier mapping matrices)去分析位元錯誤率，並利用我們所分析的結果去建構出一凸最佳化問題(convex optimization problem)去使得位元錯誤率最小化，並且找出最佳的資源分配矩陣藉由一整數的條件放寬。接著從最佳化問題中的結果提出兩種資源分配之演算法，一種為公平資源分配(Fair resource allocation)，另一種為激進資源分配 (Aggressive resource allocation)。而最後我們模擬結果可以看出，我們將適當的子載波分配給不同使用者，並利用我們所提出的演算法有效的克服了子載波間干擾的產生以及增進了元錯誤率之效能。
| zh_TW |
| dc.description.abstract | The demand for high data rate wireless multimedia applications has been significantly increasing in mobile communication. Single-carrier frequency-division multiple access (SC-FDMA) is a promising and power-efficiency technique which allows for lower peak-to-average power ratio(PAPR). Essentially, the SC-FDMA system has a similar transmitter structure to the orthogonal frequency division multiplexing access (OFDMA) systems except that the information-bearing data symbols are pre-coded in frequency domain via a discrete Fourier transform (DFT) operation. Hence,it is suitable for uplink multiple access, especially when the issue of battery life represents a key concern in the next-generation wireless communication systems. In Third-Generation Partnership Project (3GPP) community, the SC-FDMA has been selected as the multiple access scheme for uplink transmission in the long-term evolution (LTE) specifications.
In this thesis, we investigate two kinds of minimum mean square error (MMSE)-based equalizers to compensate for the inter-carrier interference (ICI), caused by the Doppler effect, in LTE uplink SC-FDMA systems. One is the multi-user (MU)-MMSE equalizer and the other is called single-user(SU)-MMSE equalizer. The MU-MMSE equalizer can achieve better performance, whereas it has higher computational complexity. Instead, the SU-MMSE equalizer applies the band-limited structure of the ICI matrix to effectively reduce the computation complexity although it might suffer from a slight performance degradation on bit error rate (BER). Besides, we also develop an iterative receiver by incorporating the ICI cancellation scheme into the SU-MMSE equalization scheme to enhance the BER performance. Simulation results show that the proposed scheme can significantly improve the system performance.
In LTE uplink SC-FDMA system, the resource allocation among users will affect the BER performance in mobile radio environments. We introduce a novel idea to relieve the ICI effect from the upper-layer chunk resource allocation. First, we analyze the BER performance in terms of the users’
subcarrier mapping matrices, and formulate a convex optimization problem to minimize the BER by optimizing the resource allocation matrices through the integer constraint relaxation. Two resource allocation algorithms are then proposed to quantize the optimization results from the viewpoints of fair subcarrier allocation and aggressive subcarrier allocation. Simulation results demonstrate that with appropriate resource allocation among users, the proposed algorithms can effectively avoid severe ICI
from other users and thereby significantly improve the BER performance.
| en_US |
| DC.subject | 資源分配 | zh_TW |
| DC.subject | 等化器 | zh_TW |
| DC.subject | 第四代行動通訊 | zh_TW |
| DC.subject | LTE | en_US |
| DC.subject | SC-FDMA | en_US |
| DC.subject | resource allocation | en_US |
| DC.subject | ICI | en_US |
| DC.subject | Equalizer | en_US |
| DC.title | 應用於行動LTE 上鏈SC-FDMA 系統之通道等化與資源分配演算法 | zh_TW |
| dc.language.iso | zh-TW | zh-TW |
| DC.title | Channel Equalization and Resource Allocation for LTE Uplink SC-FDMA Systems in Mobile Radio Channels | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |