In this paper, the performance of two multirate schemes in DS/CDMA systems: Variable Spreading Gain (VSG-CDMA) and Multicode (MC-CDMA) are compared. We will first present the signal model for multirate DS/CDMA system. Then, the performance in terms of asymptotic multiuser efficiency (AME), near-far resistance (NFR), and BER are evaluated. Some typical detectors are considered in multirate systems. These include the optimal Maximum-Likelihood detector, the sub-optimal linear detector, the interference canceller and the conventional MF detector. We will show that in multirate systems, MC-CDMA has a very similar performance as VSG-CDMA employing low-rate detection (LRD). But it performs much better than VSG-CDMA employing high-rate detection (HRD). Furthermore, we will show some important distinctions between multirate systems and single-rate systems.
|Number of pages||5|
|Journal||IEEE Vehicular Technology Conference|
|Publication status||Published - 2001|
ASJC Scopus subject areas
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering