dc.contributor.advisor |
Mondal, 1Dr. Md. Rubaiyat Hossain |
|
dc.contributor.author |
Nowrin, Itisha |
|
dc.date.accessioned |
2022-06-28T04:38:47Z |
|
dc.date.available |
2022-06-28T04:38:47Z |
|
dc.date.issued |
2021-03-13 |
|
dc.identifier.uri |
http://lib.buet.ac.bd:8080/xmlui/handle/123456789/6034 |
|
dc.description.abstract |
This thesis proposes a new hybrid orthogonal frequency division multiplexing (OFDM) modulation technique termed as DC-biased Pulse amplitude modulated Optical OFDM (DPO-OFDM) for light fidelity (LiFi) systems. The proposed DPO-OFDM scheme is the combination of two existing OFDM formats: DC-biased Optical OFDM (DCO-OFDM) and Pulse Amplitude Modulated discrete multitone (PAM-DMT). In DPO-OFDM, the odd index subcarriers carry DCO-OFDM, and the imaginary part of even index subcarriers carry PAM-DMT component. Analysis indicates that the required DC-bias for DPO-OFDM is a function of the dimming and root mean square of its two components' values. Simulation results show that for an uncoded bit error rate (BER) of 10-3, the dimming range for DPO-OFDM is 3% to 97% with acceptable spectral efficiency. Furthermore, a switching algorithm for HDAP-OFDM is proposed where the individual components of HDAP-OFDM are switched according to a target dimming level. Next, machine learning algorithms are used to find the appropriate proportions of DPO-OFDM components. For this, a dataset is created for DPO-OFDM system simulated using the MATLAB tool. Using Python programming language, it is shown here that polynomial regression of degree 4 can reliable predict the constellation size of DCO-OFDM component of DPO-OFDM for a given constellation size of PAM-DMT and a given target dimming level. Hence, the findings of this thesis can contribute in developing a practical LiFi system capable of reliable Internet connection and room illumination. |
en_US |
dc.language.iso |
en |
en_US |
dc.publisher |
Institute of Information and Commutation Technology |
en_US |
dc.subject |
Wireless communication systems-OFDM |
en_US |
dc.title |
Machine learning based dimming control of orthogonal frequency division multiplexing based light fidelity |
en_US |
dc.type |
Thesis-MSc |
en_US |
dc.contributor.id |
0417312034, |
en_US |
dc.identifier.accessionNumber |
118600 |
|
dc.contributor.callno |
623.82/ITI/2021 |
en_US |