Peak to average power ratio analysis for LTE systems

The 3rd generation partnership project (3GPP) long term evolution (LTE) standard uses single carrier frequency division multiple access (SCFDMA) scheme for the uplink transmissions and orthogonal frequency division multiplexing access (OFDMA) in downlink. SCFDMA uses DFT spreading prior to OFDMA modulation to map the signal from each user to a subset of the available subcarriers i.e., single carrier modulation. The efficiency of a power amplifier is determined by the peak to average power ratio (PAPR) of the modulated signal. In this paper, we analyze the PAPR in 3GPP LTE systems using root raised cosine based filter. Simulation results show that the SCFDMA subcarrier mapping has a significantly lower PAPR compared to OFDMA. Also comparing the three forms of SCFDMA subcarrier mapping, results show that interleave FDMA (IFDMA) subcarrier mapping with proposed root raised cosine filter reduced PAPR significantly than localized FDMA (LFDMA) and distributed (DFDMA) mapping. This improves its radio frequency (RF) power amplifier efficiency and also the mean power output from a battery driven mobile terminal.<br /

Implementing the SC-FDMA transmission technique using the GNURadio platform

Dissertação apresentada para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores, pela Universidade Nova de Lisboa, Faculdade de Ciências e TecnologiaFCT/MEC - (PTDC/EEA- TEL/120666/2010), MANY2COMWIN (EXPL/EEI-TEL/0969/2013) and ADIN (PTDC/EEI-TEL/2990/2012

IMPLEMENTATION AND PERFORMANCE ANALYSIS OF LONG TERM EVOLUTION USING SOFTWARE DEFINED RADIO

The overwhelming changes in the field of communication brought about need for high data rates, which led to the development of a system known as Long Term Evolution (LTE). LTE made good use of Orthogonal Frequency Division Multiplexing Access (OFDMA) in its downlink and Single Carrier Frequency Division Multiplexing Access (SCFDMA) in its uplink transmission because of their robust performance. These multiple access techniques are the major focus of study in this thesis, with their implementation in the LTE system. GNU Radio is a software Defined Radio (SDR) platform. It comprises of C++ signal processing libraries. For user simplicity, it has graphical user interface (GUI) known as GNU Radio Companion (GRC), to build a signal processing flow graph. GRC translates any specific task flow graph to a python program which calls inbuiltC++ signal processing blocks. By leveraging this feature and existing modules in GRC, OFDMA and SCFDMA is implemented. In this study we made use of existing OFDMA flow graph of GNU Radio to study the behavior of downlink and general performing SCFDMA system was implemented with some modifications of the existing GNU Radio blocks. With the GNU Radio implementation, we tested the working mechanism of both the systems. OFDMA is used in downlink for achieving high spectral efficiency and SCFDMA was introduced in uplink due to its low PAPR feature. These multiple access schemes have to meet the requirement of high throughput with low BER and PAPR, low delays and low complexity. In this thesis we are focused on evaluating these multiple access techniques in terms of BER and PAPR with modulation techniques like QPSK, 16-QAM and 64-QAM. Performance analysis part is performed in MATLAB

PAPR reduction in OFDM communications with generalized discrete Fourier transform

The main advantage of Generalized Discrete Fourier Transform (GDFT) is its ability to design a wide selection of constant modulus orthogonal code sets, based on the desired performance metrics mimicking the engineering specs of interest. One of the main drawbacks of Orthogonal Frequency Division Multiplexing (OFDM) systems is the high Peak to Average Power Ratio (PAPR) value which is directly related to power consumption of the system. Discrete Fourier Transform (DFT) spread OFDM technology, also known as Single Carrier Frequency Division Multiple Access (SCFDMA), which has a lower PAPR value, is used for uplink channel. In this thesis, the PAPR of DFT spread OFDM was further decreased by using a GDFT concept. The performance improvements of GDFT based PAPR reduction for various SCFDMA communications scenarios were evaluated by simulations. Performance simulation results showed that PAPR efficiency of SCFDMA systems for Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) and 16 Quadrature Amplitude Modulation (16-QAM), digital modulation techniques are increased

Analisis Peak to Average Power Ratio (Papr) Single Carrier Frequency Division Multiple Access (Sc-fdma) Pada Long Term Evolution (Lte)

Single Carrier Frequency Division Multiple Access (SC-FDMA) merupakan bentuk modifikasi dari pendahulunya yaitu Orthogonal Frequency Division Multiple Access (OFDMA). SC-FDMA mewarisi kelebihan-kelebihan yang dimiliki OFDMA, namun SC-FDMA memiliki suatu kelebihan yang tidak dimiliki oleh OFDMA yaitu nilai Peak to Average Power Ratio (PAPR) yang lebih rendah. Peak to Average Power Ratio (PAPR) adalah suatu performansi yang digunakan untuk menentukan indikasi efisiensi daya dari suatu transmitter. Semakin rendah nilai PAPR maka efisiensi daya yang dihasilkan adalah semakin tinggi. Analisis yang dilakukan adalah perbandingan nilai PAPR pada sistem SC-FDMA, yang mana pada SC-FDMA terdapat tiga metode pemetaan subcarrier yaitu, Interleaved-FDMA, Distributed-FDMA, dan Localized-FDMA. Simulasi dilakukan pada ketiga jenis pemetaan subcarrier pada SC-FDMA. Dari hasil simulasi matematis didapatkan hasil bahwa pada Interleaved-FDMA memiliki nilai PAPR yang paling rendah jika dibandingkan dengan Localized-FDMA dan Distributed-FDMA. Jika dibandingkan dengan PAPR yang menggunakan pulse shaping, pada saat diaplikasikan raised cosine filter, niali PAPR IFDMA tanpa penggunaan pulse shaping adalah sebesar 0 dB untuk teknik modulasi QPSK, 3.718 dB untuk 16-QAM, dan 4.897 dB untuk 64-QAM. Sedangkan saat diaplikasikan root raised cosine filter, nilai PAPR IFDMA tanpa penggunaan pulse shaping adalah sebesar 0 dB untuk teknik modulasi QPSK, 3.792 dB untuk 16-QAM, dan 4.916 dB untuk 64-QAM.Kata Kunci - Distributed-FDMA, Interleaved-FDMA, Localized-FDMA, Peak to Average Power Ratio (PAPR), Single Carrier Frequency Division Multiple Access (SC-FDMA)

A COMPARATIVE ANALYSIS OF PAPR OF SC-FDMA AND OFDMA FOR LTE SYSTEMS

Long Term Evolution is a new advancement in the era of cellular technology emerged in recent decade that can accommodate the features of quite efficient radio access with high peak data rates as well as high capacity for voice links. Actually it is a journey toward 4th generation with the recent 2G and 3G network operators. This revolution is an improvement over GSM, EDGE G, WCDMA/UMTS, and HSPDA and then HSPA+ to fulfil the demand of high speed mobile networks. This paper primarily describes a comparison of Single Carrier Frequency Division Multiple Access (SC-FDMA) and Orthogonal Frequency Division Multiple Access (OFDMA) multiple access techniques.This comparison is carried out for the selection of multiple access schemes for the implementation of Long Term Evolution (LTE) systems. Also the advantages and disadvantages of SC-FDMA and OFDMA schemes are described. SC-FDMA is proved better than OFDMA in terms of Peak to average power ratio (PAPR).SCFDMA and OFDMA systems are modelled with MATLAB for PAPR analysis

ANALISA KINERJA SISTEM SINGLE CARRIER-FREQUENCY DIVISION MULTIPLE ACCESS UNTUK TRANSMISI CITRA

Teknologi Long Term Evolution (LTE) menggunakan 2 sistem pada sisi yang berbeda, yaitu pada sisi downlink dengan OFDMA dan SC-FDMA pada sisi uplink. SC-FDMA memiliki kelebihan pada sisi efisiensi daya dibandingkan dengan OFDMA. Berdasarkan 3GPP Release 8, modulasi LTE meliputi QPSK, 16-QAM dan 64QAM. Penelitian ini bertujuan untuk mengetahui karakteristik BER dan PAPR terhadap SNR, menganalisis perbandingan BER dan PAPR terhadap SNR pada sistem SC-FDMA, dan mengetahui perbandingan kinerja teknik modulasi QPSK, 16-QAM dan 64-QAM. Hasil kinerja sistem melewati kanal yang berdistribusi Rayleigh. Penelitian dijalankan dengan melakukan simulasi pengiriman citra melalui kanal Rayleigh Fading menggunakan modulasi QPSK, 16-QAM, dan 64-QAM. Parameter SNR yang diteliti sebesar 0-16 dB. Hasil simulasi menunjukkan bahwa SC-FDMA memiliki ketahanan noise yang lebih tinggi saat menggunakan modulasi QPSK dengan BER = 0 dB saat SNR = 13 dB dan PAPR yang stabil di angka 0,9 dB