Date of Award

Fall 1994

Document Type

Thesis

Degree Name

Master of Science in Electrical Engineering - (M.S.)

Department

Electrical and Computer Engineering

First Advisor

Bar-Ness, Yeheskel

Second Advisor

Ansari, Nirwan

Third Advisor

Siveski, Zoran

Abstract

In this thesis, the detection of Direct Sequence Code Division Multiple Access (DS-CDMA) signals in an AWGN channel and Multi-Carrier (MC) CDMA signals in a time-dispersion channel is discussed.

The DS-CDMA receiver employs an adaptive multiuser interference canceler that utilizes deadzone limiters in the tentative decision stage. With weights adjusted adaptively, the prior knowledge of signal powers is unnecessary. The steady state error performance of this receiver is obtained and found to be superior to the performance of the same receiver using hard limiters for tentative decisions. The channel is considered non-fading in. this receiver.

Modeling the frequency selective channel lading as narrowband fiat-flat fading centered at each subcarrier, the MC-CDMA technique reduces the effect of channel dispersion. A decorrelating multiuser interference canceler is introduced in the MC-CDMA receiver to reduce the multi-access interference, especially when the orthogonality of signature codes is degraded by the fading channel.

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