Abstract
This paper studies the multiple relays amplify-and-forward (AF) cooperative communication system with adaptive continuous (ACR) and discrete rate (ADR) M-QAM modulation in Rayleigh fading channel. The average spectral efficiency of the fixed ACR, ADR M-QAM schemes with various number of relays are researched and analyzed. We first obtain quantitative spectral efficiency loss for the fixed rate M-QAM scheme resulting from the increasing number of the relay nodes. It is verified that under certain BER level, the adaptive M-QAM scheme achieves significant efficiency gains over the non-adaptive one. And, the more constellation size is available in ADR M-QAM, the closer the BER approaches to the target level and the more potentialities of the spectral efficiency can be realized.
| Original language | English |
|---|---|
| Pages (from-to) | 274-278 |
| Number of pages | 5 |
| Journal | Journal of Theoretical and Applied Information Technology |
| Volume | 43 |
| Issue number | 2 |
| State | Published - Sep 2012 |
Keywords
- Adaptive modulation
- Amplify-and-forward cooperative communication system
- Average spectral efficiency