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Ultrashort Pulse Receiver Design Via Statistical Invariance Principle

Farhang, Mahmoud | 2010

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 40462 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Salehi, Javad
  7. Abstract:
  8. With the emergence and development of ultra broadband communication systems incorporating ultrashort pulses, the design of suitable receiver structures became one the most significant problems in such systems; since due the limited bandwidth and speed of current electronic devices, most of the existing receiver structures cannot be used properly. In the field of radio communications, the design of simple and low power consumption receivers for ultrawideband (UWB) and millimeter wave band communication systems, which do not rely on complex channel estimation mechanisms, is of much interest. In ultrashort light pulse optical communication systems –and specially coherent optical CDMA systems– detection of ultrashort light pulses with conventional bandlimited photodetectors can lead to substantial performance degradation, and all-optical nonlinear processing of the received field prior to the optical to electrical conversion becomes inevitable. In this thesis, with the help of statistical decision theory and an application of the invariance principle, we try to derive the structure of the optimum receiver in the above systems. In particular, we show that in UWB systems with unknown channel, energy detector is the optimum receiver. Moreover, we obtain the optimum receiver for transmitted-reference signaling and evaluate its performance. The results imply that allocating a part of the transmitted energy and bandwidth to reference pulses would not help improve the performance of the system. Also, after obtaining the optimum nonlinear element in the ultrashort light pulse receiver structure and its performance analysis, possible suboptimum nonlinearities are investigated and their performance is examined, and the results show how by using them almost optimal performance can be achieved
  9. Keywords:
  10. Wideband Communication ; Optical Communication ; Ultrashort Pulsed Lasers ; Optimum Receiver ; Statistical Invariance Principle

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