Spectrum Efficiency Calculator
Calculate spectral efficiency and channel capacity for wireless systems.
Modulation Efficiency Reference
| Modulation | bits/symbol | Min SNR (dB) | Typical Use |
|---|---|---|---|
| BPSK | 1 | ~7 | Satellite, weak signals |
| QPSK | 2 | ~10 | LTE edge, satellite |
| 16-QAM | 4 | ~17 | LTE mid-range |
| 64-QAM | 6 | ~23 | LTE/WiFi good signal |
| 256-QAM | 8 | ~29 | WiFi 5/6, LTE-A |
| 1024-QAM | 10 | ~35 | WiFi 6, 5G NR |
Spectral Efficiency Theory
Shannon-Hartley Theorem
C = B * log2(1 + SNR)
C = capacity (bits/s), B = bandwidth (Hz), SNR = linear ratio
C = capacity (bits/s), B = bandwidth (Hz), SNR = linear ratio
The Shannon limit represents the theoretical maximum data rate achievable over a noisy channel. Practical systems achieve 50-80% of this limit due to implementation losses.
Practical Efficiency
SE = (bits/symbol) * (code rate) * (1 - overhead)
SE in bits/s/Hz
SE in bits/s/Hz
Real-world spectral efficiency depends on modulation order, error correction coding, and protocol overhead (guard intervals, pilots, headers).