Title page for ETD etd-08162005-101502


Type of Document Master's Thesis
Author Ilunga, Lou
URN etd-08162005-101502
Title Adaptive, Turbo-coded OFDM
Degree Master of Science
Department Electrical and Computer Engineering
Advisory Committee
Advisor Name Title
Annamalai, Annamalai Jr. Committee Chair
Jacobs, Ira Committee Member
Reed, Jeffrey Hugh Committee Member
Keywords
  • doppler
  • frequency selective rayleigh channel
  • adaptive modulation
  • turbo codes
  • orthogonal frequency division multiplexing
  • target BER
Date of Defense 2005-06-30
Availability unrestricted
Abstract
Wireless technologies, such as satellite, cellular, and wireless internet are now commercially driven by ever more demanding consumers, who are ready for seamless integration of communication networks from the home to the car, and into the office. There is a growing need to quickly transmit information wirelessly and accurately. Engineers have already combine techniques such as orthogonal frequency division multiplexing (OFDM) suitable for high data rate transmission with forward error correction (FEC) methods over wireless channels.

In this thesis, we enhance the system throughput of a working OFDM system by adding turbo coding and adaptive modulation (AD). Simulation is done over a time varying, frequency selective Rayleigh fading channel. The temporal variations in the simulated wireless channel are due to the presence of Doppler, a sign of relative motion between transmitter and receiver. The wideband system has 48 data sub-channels, each is individually modulated according to channel state information acquired during the previous burst. The end goal is to increase the system throughput while maintaining system performance under a bit error rate (BER) of 10-2. The results we obtained are preliminary. The lack of resources prevented us from producing detailed graphs of our findings.

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