Digital predistortion for compensation of nonlinearities in Radio over Fiber Links

Hadi, Muhammad Usman (2016) Digital predistortion for compensation of nonlinearities in Radio over Fiber Links. [Laurea magistrale], Università di Bologna, Corso di Studio in Ingegneria elettronica [LM-DM270], Documento full-text non disponibile
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In order to cope up with the ever increasing demand for larger transmission bandwidth, Radio over Fiber technology is a very beneficial solution. These systems are expected to play a major role within future fifth generation wireless networks due to their inherent capillary distribution properties. Nonlinear compensation techniques are becoming increasingly important to improve the performance of telecommunication channels by compensating for channel nonlinearities. Indeed, significant bounds on the technology usability and performance degradation occur due to nonlinear characteristics of optical transmitter, nonlinear generation of spurious frequencies, which, in the case of RoF links exploiting Directly Modulated Lasers , has the combined effect of laser chirp and optical fiber dispersion among its prevailing causes. The purpose of the research is to analyze some of the main causes of harmonic and intermodulation distortion present in Radio over Fiber (RoF) links, and to suggest a solution to reduce their effects, through a digital predistortion technique. Predistortion is an effective and interesting solution to linearize and this allows to demonstrate that the laser’s chirp and the optical fiber’s dispersion are the main causes which generate harmonic distortion. The improvements illustrated are only theoretical, based on a feasibility point of view. The simulations performed lead to significant improvements for short and long distances of radio over fiber link lengths. The algorithm utilized for simulation has been implemented on MATLAB. The effects of chirp and fiber nonlinearity in a directly modulated fiber transmission system are investigated by simulation, and a cost effective and rather simple technique for compensating these effects is discussed. A detailed description of its functional model is given, and its attractive features both in terms of quality improvement of the received signal, and cost effectiveness of the system are illustrated.

Tipologia del documento
Tesi di laurea (Laurea magistrale)
Autore della tesi
Hadi, Muhammad Usman
Relatore della tesi
Correlatore della tesi
Corso di studio
Curriculum: Electronics and communication science and technology
Ordinamento Cds
Parole chiave
Radio over Fiber,Directly Modulated Laser,Second-order Harmonic Distortion,Input Intercept Point of Order 2,Input Intercept Point of Order 3,Predistortion Technique,Intermodulation Distortion,Laser Chirp,Optical Fiber Dispersion,Nonlinear Effects,Laser Inversion,Integral Approximation,Derivative Approximation
Data di discussione della Tesi
7 Ottobre 2016

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