臺灣博碩士論文加值系統

In supporting the multi-user communications, OFDMA has been utilized to construct the download LTE system. In this paper we demonstrated that the OFDMA system using the Pilot Assisted Channel Estimation (PACE) performs poorly at high-vehicle speed. Hence we introduce a static RLS channel
equalization assisted OFDMA system which outperforms the former OFDMA system by 2 dB at the target BER of 0.1. Moreover, in order to reduce the power consumption of the OFDMA receiver equipped with the static RLS equalization, we propose a novel dynamic RLS channel equalization
assisted OFDMA system. In the simulation results, we showed that when the high-level modulation 64-QAM was exploited, the proposed dynamic RLS channel equalization assisted OFDMA system outperformed the PACE aided counterpart system by about 4 dB at the target BER of 0.05.

Abstract i
Acknowledgements i
Contents iii
1 Introduction 1
1.1 Background . . . . . . 1
1.2 Motivation . . . . . . 2
1.3 Organization . . . . . . 3
2 Overview of OFDMA System and LTE Physical Layer 5
2.1 Introduction OFDM System . . . . . . 5
2.2 Introduction OFDMA System .. . . . . 6
2.3 Introduction LTE Downlink System . . . . . . 8
2.3.1 Physical Resource and Slot Structure . . .. . . 9
2.3.2 LTE Downlink Reference Signals Structure . . . . . 10
2.3.3 LTE Downlink Parameters . . . . . . 12
3 OFDMA System Model and Radio Propagation Models 14
3.1 OFDMA System Model . . . . . . 14
3.2 Radio Propagation Models . . . . . . 15
3.2.1 Introduction . . .. . . 15
3.2.2 Multipath Propagation Channel . . . . . . 17
3.2.3 ITU Multipath Channel Models . . . . . . 18
4 Channel Estimation and Equalization in OFDMA System 20
4.1 Pilot Assisted Channel Estimation . . . . . . 20
4.2 RLS Assisted Channel Equalization . . . . . . 22
4.2.1 Static RLS Equalization . . . . . . 26
4.2.2 Dynamic RLS Equalization . . . . . . 27
4.3 Simulation Results . . . . . . 30
5 Conclusions 37

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