Performance evaluation of an EDFA enhanced and ASE degraded millimeter-wave fiber-radio system incorporating remote local oscillator delivery | |
| Author | Parvez, Mohammad Forhadul |
| Call Number | AIT Thesis no.TC-01-13 |
| Subject(s) | Millimeter wave communication systems Millimeter waves |
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. TC-01-13 |
| Abstract | Wireless systems operating at millimeter-wave frequencies have attracted much interest as a means of providing broadband access for future multimedia application. Optical fiber is emerged as the ideal medium for distribution of millimeter-wave signals from central station to a number of base stations. While using optical fiber power losses such as insertion loss, coupling loss etc. limit the system performance. To compensate for the losses EDF A can be used. However, the Amplified Spontaneous Noise (ASE) phenomena inside EDF A become a significant factor that limits the system performance. The effect of ASE noise from EDF A on the performance of millimeter-wave fiber radio system is studied in this work. To evaluate the effect of ASE noise we proposed a new system configuration based on optical heterodyne technique. The system also includes the delivery of an electrical local oscillator signal to base stations, which can be used for downconversion of uplink millimeter-wave signals. Two Mach-Zehnder (MZ) modulators are used in system configuration. One of the MZ modulator modulates the output of a laser field by an unmodulated millimeter-wave while the other MZ modulator modulates the same laser output by a subcarrier data signal. Since same optical carrier is used in both MZ modulators the phase noises in optical carriers are correlated and cancelled at the photodetector due to heterodyning. At the base station photodetector the combined optical fields of the modulators are associated with ASE fields from EDF A. Due to optical heterodyning of signal fields with ASE fields beat noise is generated and degrades system performance. An analysis has been carried out to show the influence of ASE noise on the proposed system configuration. The result of analysis show that ASE noise degrades the system performance to a great extent compared to the performance when ASE is not included in performance analysis. Thus ASE imposes limits on the fiber link length between central station and base-station. Maximization of link length has been reported considering the effect of ASE noise by changing various system parameters such as EDF A gain, laser output power and peak amplitude of sub-carrier data signal. |
| Year | 2001 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. TC-01-13 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Sharma, A. B.; |
| Examination Committee(s) | Ahmed, Kazi M. ;Erke, Tapio; |
| Scholarship Donor(s) | SONERA, Finland; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2001 |