#TITLE_ALTERNATIVE#

• Main Author: Rizki (NIM: 13206127) Pembimbing : Trio Adiono, S.T, M.T, Ph.D., Kiki
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/16232
• Institution: Institut Teknologi Bandung

Orthogonal Frequency-Division Multiplexing (OFDM) is transmission technique <br /> <br /> <br /> <br /> <br /> that use some carriers (multicarrier) which is orthogonal for each other. OFDM <br /> <br /> <br /> <br /> <br /> use modulator for modulating data and IFFT for transforming signal from <br /> <br /> <br /> <br /> <br /> frequency domain to time domain on the transmitter side. On OFDM receiver, <br /> <br /> <br /> <br /> <br /> FFT is used for transforming signal back to frequency domain and demodulator is <br /> <br /> <br /> <br /> <br /> used for demodulating received data. Modulator-demodulator and FFT/IFFT is <br /> <br /> <br /> <br /> <br /> needed in OFDM system. <br /> <br /> <br /> <br /> <br /> Channel Coding is used for conditioning and protecting information data with a <br /> <br /> <br /> <br /> <br /> sequence of Code to protect data from error. One of Code that widely used is <br /> <br /> <br /> <br /> <br /> Reed-Solomon (RS) Code. RS Code has good performance in correcting error. RS <br /> <br /> <br /> <br /> <br /> Code is used in a lot of telecommunication applications. <br /> <br /> <br /> <br /> <br /> Modulator and demodulator are designed to do modulation and demodulation on <br /> <br /> <br /> <br /> <br /> 3 modulations schemes, which is QPSK, 16-QAM and 64-QAM. FFT/IFFT that <br /> <br /> <br /> <br /> <br /> designed are using 3 computation stage with Radix 8. On RS Code, the algorithm <br /> <br /> <br /> <br /> <br /> used for decoding is Reformulated Inversionless Berlekamp-Massey (RiBM). <br /> <br /> <br /> <br /> <br /> The design process of OFDM and RS Code modeling is started by defining the <br /> <br /> <br /> <br /> <br /> system’s specification. From the specification, certain algorithm is chosen. From <br /> <br /> <br /> <br /> <br /> mathematical description of this algorithm, functional model is designed. After <br /> <br /> <br /> <br /> <br /> simulating functional model, we get Bit Error Rate (BER) graph. Then, hardware <br /> <br /> <br /> <br /> <br /> modeling is done by using bit precision method. Bit precision model simulated in <br /> <br /> <br /> <br /> <br /> iv <br /> <br /> <br /> <br /> <br /> some variance of bit length of fixed-point and optimization in FFT/IFFT module. <br /> <br /> <br /> <br /> <br /> Bit precision BER graph is analyzed and compared to reference BER graph for <br /> <br /> <br /> <br /> <br /> measuring bit precision system. Analysis result is used for deciding the length of <br /> <br /> <br /> <br /> <br /> bit in fixed-point and the best optimization for FFT/IFFT. For RS Code, <br /> <br /> <br /> <br /> <br /> functional computation result is used for verifying bit precision computation <br /> <br /> <br /> <br /> <br /> result. All of the design is described in MATLAB. <br /> <br /> <br /> <br /> <br /> Simulation result shows that bit precision model for OFDM and RS Code can <br /> <br /> <br /> <br /> <br /> generate system with good performance. Ion OFDM, for QPSK and 16-QAM <br /> <br /> <br /> <br /> <br /> modulation scheme, when BER reaches 10-4, the difference between reference <br /> <br /> <br /> <br /> <br /> ebn0 and bit precision ebn0 is less than 2 dB. In RS Code, RS decoder <br /> <br /> <br /> <br /> <br /> computation result is exactly same with RS encoder input.