Electrical Computer Engineering

Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/74

Browse

Filters

2021 - 20222

Settings

Subject: search.filters.subject.Bit error rate

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Performance Analysis of High Speed Fiber Optic Communication Systems with Optical OFDM and Dispersion Compensation Technique
    (Hawassa University, 2022-04-20) GIRMA HASENA HINSENE
    Several designers are employing fiber optics instead of copper wire to transport information between data ports to fulfill the high-speed requirements of today's communication systems since it offers several advantages such as high transmission capacity and low losses. Limitations and flaws such as chromatic dispersion hamper the performance of optical fiber communication systems. Tolerating the effects of chromatic dispersion in optical communication systems, various classic dispersion compensation techniques such as Dispersion Compensation Fiber (DCF) and Fiber Bragg Grating (FBG) have been used. Advanced modulation schemes, such as orthogonal frequency division multiplexing (OFDM), are excellent candidates for improving spectrum efficiency in communication systems by reducing chromatic dispersion effects. That is FBG uses the principle of recompression of light signals with different wavelengths to reduce the effect of chromatic dispersion. And OFDM uses the orthogonality principle between subcarriers with the insertion of cyclic prefix and guard bands to reduce the effect of chromatic dispersion. The performance of a high-speed optical fiber communication system was investigated using coherent optical OFDM (Co-O-OFDM) and Fiber Bragg grating (FBG) as dispersion compensation techniques in this thesis study. The system models were simulated using Optisystem simulation software, and the output was plotted using MATLAB. Performance measuring metrics such as optical signal to noise ratio (OSNR), bit error rate (BER) and Quality-factor were used to thoroughly examine the results. RF spectrum, optical spectrum, and constellation diagram of the signal were examined at different distances to see the effect of chromatic dispersion. The performance of both DP-16QAM Co-O-OFDM and FBG integrated DP-16QAM Co-O-OFDM systems declined as the signal propagated long distances of fiber optic for four different rates due effect of chromatic dispersion, and FBG integrated DP-16QAM Co-O-OFDM system performed better for the same rate and distance due to integration of FBG.
  • No Thumbnail Available
    Item
    Performance Comparison of Multiple Access Techniques for 5G networks and beyond
    (Hawassa University, 2021-10-22) Habtamu Gure
    In wireless networks, the rapidly growing demands for wireless services are encountered by the shortage of the existing radio resources. More spectrum is needed not only to accommodate more users, but also to satisfy the demands of new services such as wireless gaming, TV on demand, Self-driving cars and high-speed mobile data. Filter bank multicarrier (FBMC), universal filtered multicarrier (UFMC) and power domain non-orthogonal multiple access (PD-NOMA) have currently get attention because of their higher spectrum efficiency compared to OFDM, and they play an important role in increasing the capacity in future networks. Particularly, FBMC and UFMC is unlike OFDM, they can be eliminate cyclic prefix and reduce out of band emission by using different filters for each subchannels and for sub-band respectively, whereas PD-NOMA accommodate multiple users in the power domain through superposition coding and make them to access the whole spectrum simultaneously, while using successive interference cancellation (SIC) at the receiver side for signal detection. This thesis provide the performance comparison and analyze of FBMC, UFMC and PD-NOMA multiple access techniquesin system-level performance with respect to spectrum efficiency, energy efficiency, bit-error rate, and PAPR. Results indicate that power domain NOMA perform better in spectral efficiency, energy efficiency and PAPR than FBMC and UFMC schemes. The results also reveal that PD-NOMA less perform than FBMC and UFMC in respect of bit error rate. From the results we conclude that the power domain based NOMA is good candidate to 5G network as compared to the FBMC and UFMC with cost of bit error rate.