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Narrowband Interference Cancellation in Wireless Ultra Wideband Communication Systems via Three-Level Spread Time Codes

Mashhadi, Saeed | 2009

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 39442 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Salehi, Javad
  7. Abstract:
  8. Achieving various data rates over a wide range of applications and in a multiple-access scenario should be done under certain power and bandwidth constraints. Emerging UWB communications has opened a novel perspective against different wireless network challenges, especially overwhelming data rates. In the research field, we begin our thesis with exposition of UWB, narrowband interference and spread time codes. We elaborate on the properties of spread time codes through frequency domain analysis of a reusable multiple-access scheme. Evaluating the variance of ISI, MAI and RUI, we demonstrate the spread time codes behave in an optimum manner, i.e., the most RUI resistibility, along with all other correlation-based systems. Afterward, we analyze and compare performances of the two- and three-level spread time codes in combat multiple Gaussian narrowband interferences. Simulation results, over AWGN with correlator and UWB with RAKE scenarios, strongly verify the analytical conclusions. Through an extremely important, simple and yet practical example, we show that the system performance may be evaluated with the help of a limited number of characteristic parameters. Next, introducing PLP as the probability of stretching power from a pre-specified threshold, we find novel upper bounds on the instantaneous power profile of the spread time system. We discuss various properties owing to PLP and elaborate on the main parameters affecting the PLP value. Finally, we establish a key design parameter which relates the most important quantities affecting the PLP, and show that using suitable distributions will bring some distribution gain and thereby enhance the overall system performance
  9. Keywords:
  10. Wireless Communication ; Narrow Band Interference ; Ultra Wide Band(UWB)Wireless Communications ; Two Level Spread Time Codes ; Instantaneous Power ; Three Level Spread Time Codes

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