OFDM Parameters
Works out the timing and throughput of an OFDM waveform (Wi-Fi, LTE, 5G-NR, DVB) from its subcarrier spacing, FFT size, and cyclic-prefix length. Returns the useful symbol time, the sample rate, the CP duration and overhead, the occupied bandwidth, the peak-to-average power bound, and the raw data rate. Handy for sizing an air interface or sanity-checking a standard's numerology.
Equations & Parameters ▸
\(T_u=\dfrac{1}{\Delta f}\quad f_s=N_{FFT}\,\Delta f\quad T_{cp}=\dfrac{N_{cp}}{f_s}\quad T_{sym}=T_u+T_{cp}\)
\(BW\approx N_{used}\,\Delta f \quad \text{PAPR}_{max}=10\log_{10}N_{used}\ \text{dB}\)
\(R_b=\dfrac{N_{used}\,\log_2 M\,R_{code}}{T_{sym}}\)
\(BW\approx N_{used}\,\Delta f \quad \text{PAPR}_{max}=10\log_{10}N_{used}\ \text{dB}\)
\(R_b=\dfrac{N_{used}\,\log_2 M\,R_{code}}{T_{sym}}\)
| Δf | Subcarrier spacing (kHz). |
| NFFT | FFT/IFFT size (total subcarriers). Sets the sample rate. |
| Nused | Occupied (data + pilot) subcarriers. |
| Ncp | Cyclic-prefix length in samples. |
| M, Rcode | Modulation order and channel-code rate, for the data rate. |
Reference: 3GPP TS 36.211 (LTE) & 38.211 (NR) numerology; A. R. S. Bahai & B. R. Saltzberg, Multi-Carrier Digital Communications, 2004.
Inputs
kHz
NumerologyPower of two
Occupied
samp
Guard intervalFor data rate
0 – 1
Results
Timing
Useful symbol time Tu—
Sample rate fs—
CP duration Tcp—
Symbol time Tsym—
Spectrum & rate
Occupied bandwidth—
CP overhead—
Max PAPR bound—
Data rate Rb—
Diagram