Browsing by Author "Felix, Emmanuel"

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    Identification and establishment of multicarrier modulation and coding schemes for broadband power-line (BPL) application for developing countries (case study-Tanzania)
    (Unversity of Dar es Salaam, 2010) Felix, Emmanuel
    Telecommunications technology has grown so rapidly with a demand of more bandwidth required at less cost. Current technologies such as wireless technology (WT), Optic fiber technology, Very Small Aperture Terminal (VSAT) still are offered at high cost and not affordable for rural areas. Other alternative technologies have been proposed that could provide cheaper communications to rural areas. Power-line network is one of the alternative areas suggested. As the system is not intended for high speed signal communications there is substantial noise effect caused by the nature of the operations of the power-line systems. In this research work the best modulation and coding schemes that could mitigate noise in power-line systems and achieve Bit Error Rate (BER) of 10-6 at Signal to Noise Ratio (SNR) of about 25dB with channel capacity of 300Mb/s are explained. Modulation and Coding schemes are intended to protect and cipher signals via noisy channels. Current technologies propose the use of multicarrier modulations (known as Orthogonal Frequency Division Multiplexing-OFDM). For performance improvement, a combination of OFDM and Direct Sequence Code Division Multiple Access (DSCDMA) to form Multi Carrier Code Division Multiple Access (MC-CDMA) was suggested. Several modulation and coding schemes were simulated, BER and SNR data were recorded. MC-CDMA applying Reed Solomon Codes (RSC) showed better performance. MC-CDMA has good performance to mitigate multipaths while RSC shows good performance in overcoming burst errors as found in power-line networks. Analysis of the recorded data indicated that, at SNR of 25dB a BER performance of 10-6 could be achieved with channel capacity rate of 300Mb/s. Theoretical performance model for MC-CDMA with Reed Solomon coding is also presented. The applied simulation model did not consider power-line with ground return. A modified model that considers power-line with ground return is required to enhance broader understanding of performance of modulation and coding for such networks.