MEE10:33 Performance Evaluation of Uplink Multiple Access Techniques in LTE Mobile Communication System Ashraf AwadElkarim Widaa Ahmed Ahmed Hamza Ibrahim Makki This thesis is presented as part of Degree of Master of Science in Electrical Engineering Blekinge Institute of Technology May 2010 Blekinge Institute of Technology School of Engineering Department of Applied Signal Processing Supervisor: Prof. Abbas Mohammed Examiner: Prof. Abbas Mohammed ** This page is left blank ** Blekinge Tekniska Högskola SE–371 79 Karlskrona Tel.vx 0455-38 50 00 Fax 0455-38 50 57 II Abstract The User Equipments (UE) nowadays are able to provide various internet applications and services that raise the demand for high speed data transfer and Quality of Service (QoS). Accordingly, next generation mobile communication systems driven by these demands are expected to provide higher data rates and better link quality compared to the existing systems. Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (SC-FDMA) are strong multiple access candidates for the uplink of the International Mobile Telecommunications-Advanced (IMT-Advanced). These multiple access techniques in combination with other promising technologies such as multi-hops transmission and Multiple-Input-Multiple-Output (MIMO) will be utilized to reach the targeted IMT-Advanced system performance. In this thesis, OFDMA and SC-FDMA are adopted and studied in the uplink of Long Term Evolution (LTE). Two transmission scenarios are considered, namely the single hop transmission and the relay assisted transmission (two hops). In addition, a hybrid multiple access technique that combines the advantages of OFDMA and SC-FDMA in term of low Peak-to-Average Power Ratio (PAPR) and better link performance (in terms of Symbol Error Rate (SER)) has been proposed in relay assisted transmission scenario. Simulation results show that the proposed hybrid technique achieves better end-to-end link performance in comparison to the pure SC-FDMA technique and maintains the same PAPR value in access link. In addition, a lower PAPR is achieved compared to OFDMA case, which is an important merit in the uplink transmission due to the UE’s power resources constraint (limited battery power). Keywords: IMT-Advanced, LTE, LTE-Advanced, OFDMA, SC-FDMA, Multi-hop transmission, PAPR. Blekinge Tekniska Högskola SE–371 79 Karlskrona Tel.vx 0455-38 50 00 Fax 0455-38 50 57 III ** This page is left blank ** Blekinge Tekniska Högskola SE–371 79 Karlskrona Tel.vx 0455-38 50 00 Fax 0455-38 50 57 IV Acknowledgement All thank is due ALLAH, the most merciful, beneficent and the most gracious, who provided us with strength and ability to complete this work. We would like to thank Prof. Abbas Mohammed for giving us the opportunity to do our thesis work under his supervision, and for his constant support and guidance through the research work, without his help and expert guidance, this thesis would have never been finished. In addition, we would like to thank BTH staff for giving us the opportunity to join such a program. Blekinge Tekniska Högskola SE–371 79 Karlskrona Tel.vx 0455-38 50 00 Fax 0455-38 50 57 V Dedication To our families and friends for their encouragement and continued support, Blekinge Tekniska Högskola SE–371 79 Karlskrona Tel.vx 0455-38 50 00 Fax 0455-38 50 57 VI Contents Abstract ............................................................................................................................................... III Acknowledgement .............................................................................................................................. V Dedication ........................................................................................................................................... VI List of Figures ..................................................................................................................................... XI List of Tables .................................................................................................................................... XIV List of Acronyms ............................................................................................................................. XVI CHAPTER 1 .......................................................................................................................................... 1 Introduction .......................................................................................................................................... 1 1.1 Introduction .......................................................................................................................... 1 1.2 Thesis scope and contribution ............................................................................................ 2 1.3 Thesis report outline ............................................................................................................ 2 CHAPTER 2 .......................................................................................................................................... 4 2 An Overview of LTE and LTE-Advanced Systems ................................................................. 4 2.1 Introduction .......................................................................................................................... 4 2.2 The Trends in LTE-Advanced Standardization Process ................................................. 5 2.2.1 Networks Architecture of LTE Releases 8 ................................................................ 5 2.2.2 Key Technologies in LTE Radio Access Network ................................................... 7 2.2.3 Key Technologies Trends towards LTE- Advanced ................................................ 8 2.3 Relaying Technology in LTE/LTE-Advanced ............................................................... 10 2.3.1 Amplify and Forward Relay Strategy ..................................................................... 11 2.3.2 Decode and Forward Relay Strategy ....................................................................... 11 2.3.3 Demodulate and Forward (Detect and Forward) Relay Strategy ....................... 11 CHAPTER 3 ........................................................................................................................................ 12 3 Wireless Channel Characteristics and Multicarrier Modulation Techniques ................... 12 3.1 Introduction ........................................................................................................................ 12 3.2 Wireless Channel Characteristics ..................................................................................... 12 3.2.1 Path-Loss and Shadowing ........................................................................................ 13 3.2.2 Multipath Fading ....................................................................................................... 13 3.2.3 Doppler Shift ............................................................................................................... 14 Blekinge Tekniska Högskola SE–371 79 Karlskrona Tel.vx 0455-38 50 00 Fax 0455-38 50 57 VII 3.2.4 Flat Fading and Frequency-Selective Fading ......................................................... 14 3.2.5 Standard Models for Wireless Channel .................................................................. 14 3.3 Orthogonal Frequency Division Multiplexing (OFDM) ............................................... 15 3.3.1 OFDM Transmitter ..................................................................................................... 16 3.3.2 OFDM Receiver .......................................................................................................... 17 3.3.3 Important Parameters in OFDM based Wireless System ..................................... 17 3.4 Single Carrier Frequency Domain Equalization (SC-FDE) .......................................... 18 CHAPTER 4 ........................................................................................................................................ 20 4 Multiple Access Techniques in LTE ........................................................................................ 20 4.1 Introduction ........................................................................................................................ 20 4.2 Orthogonal Frequency Division Multiple Access (OFDMA) ...................................... 20 4.3 Single Carrier Frequency Division Multiple Access (SC-FDMA) ............................... 21 4.4 OFDMA and SC-FDMA implementation in LTE .......................................................... 22 4.4.1 Generic Frame Structure ........................................................................................... 22 4.4.2 Physical Resource Block Parameters ....................................................................... 24 4.5 Subcarriers Mapping Schemes ......................................................................................... 26 4.5.1 Localized Subcarriers Mapping Scheme ................................................................... 26 4.5.2 Distributed/Interleaved Subcarriers Mapping Scheme ......................................... 26 4.5.3 Comparison between the Localized Scheme and the Interleaved Scheme ........ 26 4.6 Peak to Average Power Ratio (PAPR) ............................................................................. 27 4.6.1 PAPR Properties of