WLAN 802.11ax Speed Calculator: Data Rate Calculation

This page describes the WLAN 802.11ax speed calculator, also known as the 802.11ax data rate calculator.

This 802.11ax speed calculator uses a calculation formula that considers the number of data subcarriers, data bits per subcarrier, OFDM symbol time, and guard interval as inputs to determine the speed or data rate as output.

EXAMPLE: 802.11ax data rate calculator:

• INPUTS:
  • NDPC = 980
  • Code rate = 0.833
  • Modulation level = 10 (i.e., 1024QAM)
  • Tb = 12.8
  • Tg = 0.8
  • Nss = 1
• OUTPUTS:
  • 802.11ax speed, Mbps = 600.249 Mbps

WLAN 802.11ax Speed or Data Rate Formula or Equation

The following formula or equation is used for this WLAN 802.11ax speed or data rate calculator.

Following are the details of 802.11ax speed calculator input parameters:

• Number of data subcarriers (NDPC): This depends on the bandwidth of the physical layer. It can be 20 MHz, 40MHz, 80MHz or 160 MHz. The values are 234 for 20MHz, 468 for 40MHz, 980 for 80 MHz, and 1960 for 160 MHz, excluding pilots.

• Code rate: This can be 1/2, 3/4, or 5/6. Enter 0.5 for 1/2, 0.75 for 3/4, and 0.833 for 5/6.

• Modulation level: Can be 1 for BPSK, 2 for QPSK, 4 for 16QAM, 6 for 64QAM, and 10 for 1024QAM. This is obtained by the Log2 function. For example, Log2(1024) gives 10.

• Symbol time duration (Tb): Fixed at 12.8 µs.

• Guard duration (Tg): Can be 0.8, 1.6, or 3.2 µs.

• Number of spatial streams (Nss): Can be 2, 3, 4, or 8. For no spatial stream, enter ‘1’ as input.