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Multiple-Access Techniques for Wireless Indooor Infrared Communication with Dispersive Link

Hamdi, Mazda | 2014

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 46469 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Nasiri-Kenari, Masoumeh
  7. Abstract:
  8. Infrared wireless local area networks are a suitable choice for a fast and cheap wireless network, providing rates over 10 Mbps with access to unregulated bandwidth. Among multiple-access techniques for infrared wireless networks, CDMA1 has attracted the most interest, due to its simple structure and power ecency. However, spreading the spectrum in CDMA prohibits exploiting the low-rate strong channel codes. The other limiting factor in infrared networks is the channel dispersion. In this thesis, these two issues are considered and an internally coded scheme for time-hopping CDMA, suitable for wireless infrared communication is proposed and with accurate modelling of infrared dispersive channel, its performance is invesstigated. In the stpart, the structure is described and the performance for the simple correlation receiver is analyzed. Statistically accurate photon counter model is used in this part. Then, the performance of the system is investigated for matched lter and correlation receiver. While the infrared channel noise can be modeled as Gaussian noise with an acceptable approximation, the channel is considered to be a additive white Gaussian noise channel. The results show that the matched lter receiver outperforms the correlation receiver. To compete ISI2 equalizers are usually utilized. Dierent kinds of equalizers like scalar DFE3, block DFE and parallel decision-feedback decoding are considered in this thesis, and the performance of the proposed system is investigated using these equalizers. In cost of complexity, the maximun likelihood sequence detector has the best performance. The results show that block DFE and PDFD are suitable choice for infrared wireless network, having sub-optimum performance and simple structure
  9. Keywords:
  10. Wireless Local Area Network ; Equalizer ; Wireless Infrared ; Wireless Communication ; Wireless Infrared Communications ; Dispersive Channel ; Internally Channel Coding

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