EVALUASI KINERJA CONVOLUTIONAL CODING RATE ½ PADA SISTEM CDMA DENGAN KANAL AWGN DAN MULTIPATH RAYLEIGH FADING

Setyadi, Bayu Dwi and Santoso, Imam and Darjat, Darjat (2011) EVALUASI KINERJA CONVOLUTIONAL CODING RATE ½ PADA SISTEM CDMA DENGAN KANAL AWGN DAN MULTIPATH RAYLEIGH FADING. Undergraduate thesis, Diponegoro University.

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Abstract

Reliability of telecommunication systems is very important, especially with the development of digital technologies that require high-quality telecommunications systems. CDMA system is intended to provide a reliable telecommunications system with a high capacity. It’s needed a method to complement these systems to be able to improve overall performance. One way to increase system performance is by the addition of channel coding in order to reduce data transmission errors. There are two types of channel coding that is often used, namely block codes and convolutional code. The method used in this final project is a convolutional encoder at the transmitter and the Viterbi decoder at the receiver. To test the performance of encoders, the system is passed on AWGN and Rayleigh Fading channels. The coding parameters that affect the system in correcting errors such as constraint length, code rate, and the generator polynomial. This research will discuss the effects of changes in length of the constraint in the convolutional encoder on the performance of DS-CDMA system. This research will also discuss the effect of interleaver on the performance of the encoding. System performance measures of the specific bit error rate on the value of Eb / No. The simulation results show that the addition of convolutional encoder capable of providing improved system performance. Implementation of convolutional encoder with constraint length 3 on the AWGN channel has BER 4x10-5 resulted in Eb/No 5dB, while the system without channel coding only produce BER 5.9x10-3 at equal Eb/No. In other words, the system can reduce the need for Eb/No of 4dB with the use of convolutional encoder. The performance of convolutional encoder in AWGN channel with the worst result by the value of constraint length 3, in Eb/No 4dB produce BER at 3x10-4, while the best performance is produced by the constraint length 11 with the BER of 1.05 x10-4. The addition of interleaver and de-interleaver can produce a better BER with an average difference of BER up to 4.7 x10-3. The performance of convolutional encoder has decreased in Rayleigh Fading. In the range of Eb/No 0dB to 15dB resulting BER is 0,07082 to 0,000115 without channel coding. Therefore the system performance has slightly increase with addition of convolutional coding, resulted BER 0,0744 to 0,00005 and with addition of interleaver has BER value 0,063245 to 0. Keywords: CDMA, convolutional coding, AWGN channel, Rayleigh Fading.

Item Type:Thesis (Undergraduate)
Subjects:T Technology > TK Electrical engineering. Electronics Nuclear engineering
Divisions:Faculty of Engineering > Department of Electrical Engineering
Faculty of Engineering > Department of Electrical Engineering
ID Code:32032
Deposited By:Mr. Sudjadi Pranoto
Deposited On:20 Dec 2011 09:03
Last Modified:20 Dec 2011 09:03

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