Performance analysis of grouped chip-level iterated multiuser detection for overloaded CDMA systems

We present the performance evaluation of a grouped chip-level iterated (CLi) multiuser detection (MUD) technique that is based on Gaussian forcing technique for overloaded synchronous code-division multiple access systems. We confirm that the new grouped CLi MUD can approach the performance of the more complex CLi MUD with brute-force search. Also, we show that the new Grouped CLi MUD can provide a greater flexibility in trading off the performance and complexity. Furthermore, by incorporating a dynamic user grouping, the performance of the new CLi MUD technique can be further improved. We show via computer simulation, at the system with 200% condition, the loss of approximately 0.3 dB compared to its brute-force counterpart is observed while reducing the complexity to more than half.