Type of Document	Master's Thesis
Author	Vasavada, Yash M.
URN	etd-5048131259631631
Title	PERFORMANCE EVALUATION OF A FREQUENCY MODULATED SPREAD-SPECTRUM SYSTEM
Degree	Master of Science
Department	Electrical and Computer Engineering
Advisory Committee	Advisor Name Title Dr. Jeffrey H. Reed Committee Chair Dr. Brian D. Woerner none Dr. Dennis G. Sweeney none
Keywords	none
Date of Defense	1996-05-01
Availability	unrestricted
Abstract Analog frequency modulated (FM) systems offer advantages of reliable speech quality and simplicity, whereas code division multiple access (CDMA) systems promise high capacity, resistance to multipath fading, and simplified frequency planning. In this thesis, we investigate the performance of a wireless local loop (WLL) system that uses the frequency modulation with the CDMA technique. The performance of the FM CDMA system is affected by the choice of the frequency demodulation method. Performance of different state-of-art DSP based FM demodulators is evaluated. Design improvements with threshold extension, pre-deemphasis, and voice companding techniques are explored, and the limitations of the DSP based FM demodulation methods are identifed. The transmitter, the channel, and the receiver of the FM CDMA system are simulated for particular values of FM bandwidth and spread-spectrum processing gain. The capacity supported by the FM CDMA sysem is estimated with different levels of orthogonal as well as non-orthognal multiple access interference. The performance of the FM CDMA system in AWGN, multipath fading, Doppler spread, and nonlinear signal processing effects is predicted. A power control algorithm for the FM CDMA system is proposed, and its effect on the system performance is studied. The capacity of the FM based wireless system may saturate as the system evolves. An adaptive FM CDMA interference cancelation technique and a digital modulation with CDMA are two approaches investigated as ways to improve system capacity.
Files	Filename       Size       Approximate Download Time (Hours:Minutes:Seconds)     28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access    etd.pdf 1.94 Mb 00:08:57 00:04:36 00:04:02 00:02:01 00:00:10   yash.pdf 1.94 Mb 00:08:57 00:04:36 00:04:02 00:02:01 00:00:10

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