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Zct precoding based slm technique for papr reduction

Zct precoding based slm technique for papr reduction / Loo Twan Zhan
Frekuensi Ortogon Bahagian Pemultipleksan (OFDM) adalah skim modulasi pelbagai pembawa yang digunakan dalam komunikasi digital talian wayar dan tanpa wayar sejak beberapa tahun lalu. Fungsi OFDM ini adalah untuk mengurangkan penyebaran kelewatan, gangguan antara simbol (ISI), gangguan antara saluran (ICI) dan kekerapan pudar terpilih disebabkan oleh pelbagai arah. Walau bagaimanapun, kelemahan utama sistem OFDM adalah Nisbah Kuasa Puncak ke Kuasa Purata (PAPR) yang tinggi. PAPR adalah salah satu parameter penting untuk memastikan kecekapan penghantaran data yang tinggi. Dalam kertas ini, sistem Transformasi matriks Zadoff Chu (ZCT) diprakodkan pemetaan pilih (SLM) berdasarkan OFDM (SLM-OFDM) dicadangkan untuk pengurangan PAPR. Teknik ini adalah berdasarkan prakod simbol buruj dengan ZCT precoder selepas pendaraban faktor putaran fasa dan sebelum Transformasi Fourier Cepat Songsang (IFFT) dalam Sistem SLM berdasarkan OFDM (SLM-OFDM). Pada peringkat awal projek tersebut, sistem parameter perlu dijelaskan. Isyarat binari menjalani skim modulasi seperti QPSK, 4QAM, 16QAM, 64QAM dan 256QAM. Isyarat termodulat didarabkan dengan faktor fasa dan melalui ZCT dengan cara baris matriks precoder sebelum memasuki IFFT. Selepas itu, salah satu isyarat mempunyai PAPR yang paling kecil dipilih dan PAPR dinilai dengan menggunakan Pelengkap Fungsi Pengagihan Kumulatif (CCDF). Keputusan simulasi prestasi PAPR dijadualkan. Pada kadar keratan di 10−3, keputusan simulasi menunjukkan bahawa sistem yang dicadangkan boleh mengurangkan PAPR sehingga 6.8 dB dengan 𝑁 = 64 atau 256 (subpembawa sistem) dan 𝑉 = 16 (urutan fasa tidak serupa) untuk 4QAM modulasi. Tambahan pula, sistem ZCT berdasarkan SLM-OFDM boleh mengelakkan kemerosotan isyarat dalam prestasi apabila melalui satu Penguat Kuasa Tinggi (HPA) yang tidak linear. _______________________________________________________________________________________________________ Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier modulation scheme that is being used in wireline and wireless digital communications for several years ago. The function of the OFDM is to reduce delay spread, inter symbol interference (ISI), inter channel interference (ICI) and frequency selective fading due to the multipath. However, the major drawback of OFDM system is high value of Peak to Average Power Ratio (PAPR). PAPR is one of the important parameters to ensure the best transmission efficiency. In this paper, Zadoff-Chu matrix Transform (ZCT) precoded Selected Mapping (SLM) based OFDM (SLM-OFDM) system is proposed for PAPR reduction. This technique is based on precoding the constellation symbols with ZCT precoder after the multiplication of phase rotation factor and before the Inverse Fast Fourier Transform (IFFT) in the SLM based OFDM (SLM-OFDM) Systems. At the beginning of the project, parameters of the system are initialized. The binary signal is undergoes modulation schemes which are QPSK, 4QAM, 16QAM, 64QAM and 256QAM. The modulated signal is multiplied with the phase factor and pass through the ZCT with row wise precoder matrix before entering IFFT. Then select one of the transmitted signal with the least PAPR and PAPR is evaluated by using Complementary Cumulative Distribution Function (CCDF). The simulation results of PAPR performance are tabulated. At the clipping rate of 10−3, simulation results show that the proposed system can reduce the PAPR up to 6.8 dB with 𝑁 = 64 or 256 (System subcarriers) and 𝑉 = 16 (Dissimilar phase sequences) for 4QAM modulation. In additional, ZCT based SLM-OFDM system can avoid signal degradation in performance when passes through a nonlinear High-Power-Amplifier (HPA).
Contributor(s):
Loo Twan Zhan - Author
Primary Item Type:
Final Year Project
Identifiers:
Call Number : 00003107007
Accession Number : 875007129
Language:
English
Subject Keywords:
Orthogonal Frequency Division Multiplexing; reduce delay spread; Average Power Ratio
First presented to the public:
6/1/2017
Original Publication Date:
4/23/2018
Previously Published By:
Universiti Sains Malaysia
Place Of Publication:
School of Electrical & Electronic Engineering
Citation:
Extents:
Number of Pages - 71
License Grantor / Date Granted:
  / ( View License )
Date Deposited
2018-04-23 11:17:05.944
Date Last Updated
2019-01-07 11:24:32.9118
Submitter:
Mohd Jasnizam Mohd Salleh

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