Turbo-coded OCC-CDMA with spatial diversity for wireless mobile communications

Abstract

Turbo codes have been used successfully for error correction in digital communications, however, their application to wireless mobile communications is still a fresh research topic. The objective of this thesis is to present a new solution that involves the usage of turbo codes, spatial diversity, and orthogonal complementary codes in a CDMA spread spectrum system in order to deliver good performance in a fading environment at low signal-to-noise ratios. The results of the research that was performed to write this thesis are presented in a modular and progressive fashion. That is, the design of a basic turbo-coded system in additive white Gaussian noise (AWGN) is developed first in order to get a good understanding of its potential in a wireless communication environment. Then the basic system design is expanded to include fading channel characteristics and multiple access spread spectrum capabilities using classical code division multiple access (CDMA) techniques. Finally, orthogonal complementary codes are used in lieu of traditional spreading codes and spatial diversity is introduced to maximize system performance.