Abstract
We study the performance of constant-power variable-rate M-QAM schemes over Nakagami fading channels. We obtain closed-form expressions for the outage probability, spectral efficiency and average bit-error-rate (BER) assuming perfect channel estimation and negligible time delay. For a target BER of 10-3, the spectral efficiency of adaptive continuous rate M-QAM comes within 5 dB of the Shannon capacity limit, and adaptive discrete rate M-QAM comes within 6.2 dB of this limit. Nonadaptive BPSK suffers a large spectral efficiency penalty relative to these adaptive techniques. We also analyze the impact of time delay on the BER of adaptive M-QAM. Results show that systems with low BER requirements will be more sensitive to time delay, but will still operate satisfactorily if the delay is below a critical value.
| Original language | English (US) |
|---|---|
| Pages | 218-233 |
| Number of pages | 16 |
| State | Published - 1997 |
| Externally published | Yes |
| Event | Proceedings of the 1997 IEEE Global Telecommunications Mini-Conference - Phoenix, AZ, USA Duration: Nov 3 1997 → Nov 8 1997 |
Other
| Other | Proceedings of the 1997 IEEE Global Telecommunications Mini-Conference |
|---|---|
| City | Phoenix, AZ, USA |
| Period | 11/3/97 → 11/8/97 |
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Global and Planetary Change