Abstract:
The standardization of Direct-Sequence CDMA (DS-CDMA) systems in the third generation of mobile communication systems has raised even more interest in exploiting the capabilities and capacity of this type of technology. However, the conventional DS-CDMA system has the major problem of Multiple Access Interference (MAI). The MAI is unavoidable because receivers deal with information which is transmitted not by a single source but by several uncoordinated and geographically separated sources. As a result, the capacity of these systems is inherently interference limited by other users.
To overcome these limitations, Multi-User Detection (MUD) emerges as a promising approach to increase the system capacity. By jointly demodulating the users in the system, this interference can be characterized and reduced thus decreasing the overall probability of error in the system. Numerous MUD algorithms have been developed to combat MAI, each having different degrees of complexity and performance. In this report, a careful analysis of MUD schemes that includes Successive Interference Cancellation (SIC) and Parallel Interference Cancellation (PIC) is completed. After thorough observation and implementation of both techniques, a new scheme in the name of Hybrid Interference Cancellation (HIC) has also been proposed. This scheme combines SIC and PIC in an organized manner exploiting the preeminent qualities of both schemes. As a final outcome, all the three models are implemented as Simulink schematics and a comparison is drawn between them.
