Performance of Ds/ssma Communications in Impulsive Channels (Nongaussian, Hard Limiter)

Performance of digital linear and nonlinear correlation receivers is studied in a multi-user environment. There are assumed to be two types of sources interfering with data transmission: multiple-access interference, and additive channel noise, which is attributed to impulsive noise sources in the environment. The contribution of multiple-access interference is examined by considering K users transmitting simultaneously over a linear channel using the binary PSK direct-sequence SSMA technique. Alternatively, the effects of the non-Gaussian impulsive channel in such a system are studied by modeling the samples of noise after front-end filtering. The performance of hard-limiting correlation receivers is compared with that of conventional linear correlation receivers in such channels by exact computation of the average bit error probabilities of these two systems. It is seen that hard-limiting correlation receivers can offer substantial improvement over the conventional linear correlator when the additive non-Gaussian channel noise exhibits impulsive behavior. Due to computational complexity, the exact analysis is limited here to systems utilizing short spreading sequences. Computationally simple methods are proposed for approximating the average error probability of the linear and hard-limiting correlation receivers when the length of the signature sequences is large. Furthermore, for linear and nonlinear correlation receivers some asymptotic results are obtained for the case of infinitely long sequences. Finally, to broaden the suboptimum DS/SSMA receiver analysis the performance of the soft-limiting correlation receiver is studied in this impulsive and multi-user environment.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Aazhang, Behnaam

• Engineering, Electronics and Electrical

Identifier

(UMI)AAI8701424

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/69340