Devy Kuswidiastuti
Institut Teknologi Sepuluh Nopember Surabaya

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Implementationand Performance Analysis of Multi Carrier-Direct Sequence-Code Division Multiple Accesson DSK TMS320C6416T Kuswidiastuti, Devy; Suwadi, Suwadi; Suryani, Titiek; Efendi, Yusuf
JAVA Journal of Electrical and Electronics Engineering Vol 13, No 2 (2015)
Publisher : JAVA Journal of Electrical and Electronics Engineering

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Abstract

Wireless Digital Communication System nowadays must have the ability to provide a high data rate and highly reliable QoS. The application of multi carrier system offers a privilege in the spectrum efficiency aspect, because of the possibility of overlapping an orthogonal subcarrier. In MC-DS-CDMA system, some user sutilizing the same broadband frequency at the same time. Each user is distinguished by applying a unique spreading code. The problem is, the code sometimes becomes correlated with each other, hence affecting multi-user interference. This problem depends on the orthogonalities of the spreading codes that is used for each user. In this paper, implementation of MC-DS-CDMA system is done using DSK TMS320C6416T platform that is controlled via matlab simu link. Performance analysis of MC-DS-CDMA system is discussed from the aspect of resulting bit error rate (BER) parameter. Simulation and measurement are conducted to measure the real performance of the MC-DS-CDMA system prototype by giving a variation of the Eb/No value. From the measurement results, it shows a similarity with the expected theoretical result. The best result is obtained when the system operate with Eb/N0≥12dB. And the system failed to for Eb/N0≤4dB.
Implementation and Performance Analysis of Convolution Codeon WARP (Wireless Open Access Research Platform) Kuswidiastuti, Devy; Suwadi, Suwadi; Suryani, Titiek; Elvia, Desrina
JAVA Journal of Electrical and Electronics Engineering Vol 13, No 1 (2015)
Publisher : JAVA Journal of Electrical and Electronics Engineering

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Abstract

In order to have a reliable and robust data transmission in digital communication system, channel coding is applied for improving the performance of the system. Convolutional code is one of channel coding technique for error detection and error correction. In this paper, convolutional code is used for improving the bit error rate (BER) performance in Quadrature Phase Shift Keying (QPSK)modulation scheme which is implemented on a Wireless Open-Access Research Platform (WARP). Based on implementation and measurement results show that with an equal transmit power (with Tx gain =20dB), QPSK modulation with convolutional code have a lower BER than the uncoded one. For convolutional code with rate =1/2 at a range of 6 meter has a BER value of 0.00065232 while the uncoded BER is 0.0048828. By comparison of the system performance with different coding rate (1/2,2/3,3/4.5/6 and 7/8), the BER performance of QPSK system with convolutional code rate of 7/8 is better that the others. It can achieve a BER of 0.00037495.