Robust multi-user detector for code division multiple access systems

• Main Author: Guevara, Maria Katrina Derez
• Other Authors: Teh Kah Chan
• Format: Theses and Dissertations
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/64789
• Institution: Nanyang Technological University

Code Division Multiple Access (CDMA) has been widely adapted in commercial applications because it increases the capacity of wireless communications systems. It allows multiple users to simultaneously access the same communication resource and transmit information. However, users experience multiple access interference (MAl) that limits direct sequence COMA (OS-COMA) system capacity and performance. Efforts must be undertaken to address it effectively. Multi-user detection is one of the techniques to mitigate the effects of MAL In this project, existing multi-user detectors in two important classifications, linear multi-user detectors and subtractive interference cancellation detectors, are reviewed, and their bit error performance is analyzed using MA TLAB simulations. Hybrid interference cancellation is then studied to determine its robustness in various fading environments, which are modeled as Rayleigh and Rician fading channels. It is concluded that different configurations of hybrid interference cancellation may be used in DS-COMA systems depending on accuracy of power control of the received user signals and amount of multipath fading.