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"Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier transmission technique that becomes the best choice in wireless high-data-rate transmission. The drawbacks of OFDM are high Peak-to-Average Power Ratio (PAPR) and sensitivity to frequency offset. High PAPR decreases the amplifier’s efficiency. The simplest PAPR reduction method is clipping, but it gives in-band and out-of-band distortion that degrades the performance of the system. There are various types of clipping, such as classical clipping, deep clipping, and smooth clipping. This paper analyses the use of low-density parity-check (LDPC) codes as an error correction coding (ECC) for those various types of clipping. The simulation results show that classical clipping gives the best performance in PAPR reduction and error probability."

"OFDM merupakan teknik multicarrier yang kini menjadi pilihan teknologi telekomunikasi untuk transmisi data rate yang tinggi. Kelemahan OFDM adalah PAPR yang tinggi dan sensitif terhadap error frekuensi carrier. PAPR yang tinggi disebabkan superposisi dari IFFT dan menyebabkan kompleksitas pada power amplifier. Untuk menangani permasalahan tersebut, terdapat beberapa teknik reduksi PAPR. Teknik reduksi PAPR yang sederhana adalah clipping, namun memberi dampak distorsi in-band dan out-of-band yang dapat mempengaruhi kinerja sistem. Untuk menangani penurunan kinerja BER karena teknik clipping, dapat digunakan kode koreksi kanal (ECC). Terdapat beberapa jenis teknik clipping, diantara lain yaitu deep clipping, classical clipping dan smooth clipping. kode ECC yang saat ini mendekati kinerja Shannon limit adalah kode Turbo dan kode LDPC. Tesis ini merancang kombinasi variasi clipping dengan teknik kode koreksi Turbo dan LDPC untuk mendapatkan sistem terbaik dalam memperoleh kinerja PAPR dan BER yang baik. Dari hasil perancangan dan hasil simulasi tersebut, didapatkan teknik classical clipping dengan kode Turbo untuk reduksi PAPR yang baik tanpa memberi penurunan BER yang besar dibandingkan teknik clipping lainnya untuk sistem OFDM.

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OFDM is a multicarrier technique that becomes the main choice of telecommunication technology for high data rate transmision. The disadvantages of OFDM are high PAPR and sensitivity to carrier frequency error. High PAPR that caused by the superposition of IFFT gives inefficiency in power amplifier. To address these problems, there are several PAPR reduction techniques. The simplest PAPR reduction technique is clipping, but the impact of in-band and outof- band distortions affect the system's performance. Error Correction Channel (ECC) can be used to handle the BER degradation due to clipping technique. There are several types of clipping techniques such as deep clipping, classical clipping and smooth clipping. ECC codes which are close to Shannon limit are Turbo codes and LDPC codes. This thesis studies the effect of ECC codes to various clipping techniques to get better system's performance (better BER). From the simulation results, it is found that classical clipping technique with Turbo code yield better PAPR redution without a large decrease in BER compared to other clipping techniques."