Abstract
For high-speed data communications, channel coding and high-level modulation will be inevitable. In this paper, we compare the turbo coded performances of DS-CDMA and MC-CDMA which are the major contenders for next generation wireless signaling technique. Minimum mean square frequency-domain equalization (MMSE-FDE) is assumed for both DS-CDMA and MC-CDMA. The log-likelihood ratio (LLR) computation is used to generate the soft decision value needed for turbo decoding. It is found that the DS-CDMA performance is the same for all spreading factor (SF) and equivalent to a fully spread MC-CDMA for all modulation levels and coding rates. For an uncoded system, DS-CDMA is better than MC-CDMA for smaller SF due to a larger frequency diversity gain. However, with turbo coding, MC-CDMA with smaller SF provides better performance due to larger coding gain owing to better frequency interleaving and severe orthogonality destruction for larger SF and DS-CDMA wherein a symbol is spread over the entire bandwidth.
| Original language | English |
|---|---|
| Pages (from-to) | 2282-2286 |
| Number of pages | 5 |
| Journal | IEEE Vehicular Technology Conference |
| Volume | 60 |
| Issue number | 3 |
| Publication status | Published - 2004 Dec 1 |
| Event | 2004 IEEE 60th Vehicular Technology Conference, VTC2004-Fall: Wireless Technologies for Global Security - Los Angeles, CA, United States Duration: 2004 Sept 26 → 2004 Sept 29 |
Keywords
- DS-CDMA
- MC-CDMA
- MMSE-FDE
- MQAM
- Turbo coding
ASJC Scopus subject areas
- Computer Science Applications
- Electrical and Electronic Engineering
- Applied Mathematics