Browsing by Author "Ombongi, Filbert"

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    Bit Error Rate Performance Analysis of a Wideband Code Division Multiple Access System Model in an Indoor Environment using Convolution Coding over Additive White Gaussian Channel
    (Volume 3, Issue 5 October 2014, 2014) Musyoki, Stephen; Kibet, Philip; Ombongi, Filbert
    The research entails the development of a WCDMA system model in an indoor environment that transmits data over an Additive White Gaussian Noise channel. In this environment the data rate is taken as 2Mbps. The performance of this model is enhanced by employing convolution coding scheme which reduced the error rate encountered in the system. The results show that the performance of the system improves when convolution coding is implemented. The performance of QPSK is found to be better that that of 16-QAM which means that QPSK is an efficient modulation scheme but its throughput is less that of 16-QAM. Therefore, there must be a trade-off between the modulation format to be applied in a given system and the error rate generates at the receiver by that format. The convolution coding improves the power efficiency of the system when it is incorporated into the system.
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    Performance Analysis of a WCDMA System Model in a Low Mobility and Indoor Environment with Channel Coding over Additive White Gaussian Noise Channel
    (2015) Musyoki, Stephen; Ombongi, Filbert; Kibet, Philip L.
    This paper has analyzed the performance a Wireless Division Multiple Access (WCDMA) system model at a data rate of 384kbps and 2Mbps over an Additive White Gaussian Noise (AWGN) channel. The signal was modulated by Quadrature Phase Shift Keying (QPSK) and Quadrature Amplitude Modulation (QAM) with modulation order, M=16. The performance of the system was enhanced by implementing convolution coding scheme. This study was important as it formed a basis through which the performance analysis can be extended to Long Term Evolution (LTE) networks which have data rates starting from 1Mbps to as high as 100Mbps.The performance of the WCDMA at these data rates was seen to improve when convolutional coding scheme was implemented. Since the Shannon capacity formula depends on the BER of a system then this improvement means an additional capacity in the channel and this can accommodate more users in the channel. The results have further shown that the choice of a modulation technique depending on the throughput required affects the BER performance of the system. Therefore, there must be a trade-off between the throughput required, the modulation format to be used and the pulse shaping filter parameters.