Transmit power reduction in multi-carrier optical wireless communications | |
| Author | Farooqui, Muhammad Zubair |
| Call Number | AIT Diss no.TC-13-05 |
| Subject(s) | Optical communications Wireless communication systems Data transmission systems |
| Note | A dissertation submitted in partial ful llment of the requirements for the degree of Doctor of Engineering in Telecommunications, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. TC-13-05 |
| Abstract | Equivalent in essence to the issue of PAPR reduction in multi-carrier radio communications, this thesis addresses the similar problem of average transmit optical power reduction in OFDM and MC-CDMA based indoor optical wireless communications employing IM/DD. Average power reduction in optical wireless systems is the crux of several researches in the last decade to cope with the eye and skin safety issues as per IrDA, ANSI and IEC standards. Two techniques of radio domain { selected mapping (SLM) and subcarrier selection { are implemented and investigated in indoor optical wireless domain for this purpose. Contrary to the radio domain, where SLM technique has been extensively under research for PAPR reduction, SLM is investigated in this thesis for average transmit optical power reduction in both optical OFDM and optical MC-CDMA with IM/DD. For the same purpose, the second approach of subcarrier selection is investigated for a simple subcarrier selection in optical OFDM and preand post- equalization based subcarrier selection for optical MC-CDMA. Analytical upper bounds for the xed DC bias are derived for the latter case. Although satisfactory power reduction is achieved using SLM, considerable power reduction is reported through subcarrier selection in both cases. Two approaches are investigated for the transmit power reduction in multi-carrier optical wireless communications employing IM/DD - selected mapping and subcarrier selection. To the best of the author's knowledge, analysis and investigations of these techniques are reported for the rst time for OFDM and MC-CMDA based indoor optical wireless communications employing IM/DD. Satisfactory to considerable transmit power reduction is observed for both cases. For OFDM based systems, about 2 dB of reduction is observed with SLM, while about 10 dB is observed for the simple subcarrier selection. On the other hand, for MC-CMDA based systems, a reduction of about 1:5 to 3:4 dB in transmit power is observed whereas 8 to 24 dB of transmit power reduction is resulted by applying equalization based subcarrier selection. Moreover, for the last case, analytical upper bound is also derived for a xed DC bias for both pre- and post- equalization based subcarrier selection. |
| Year | 2013 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. TC-13-05 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Poompat Saengudomlert; |
| Examination Committee(s) | Ahmed, Kazi Mohiuddin;Mongkol Ekpanyapong;Ghassemlooy, Zabih ; |
| Scholarship Donor(s) | Higher Education Commission (HEC), Pakistan;AIT Fellowship; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2013 |