wiki:802.11/Benchmarks/Tx_Char

Version 3 (modified by chunter, 9 years ago) (diff)

--

Transmitter Characterization

The IEEE 802.11 Standard specifies minimum tolerances on the quality of emitted waveforms from WLAN devices. These tolerances are specified in as Error Vector Magnitude (EVM) in dBm. For the OFDM PHY in 802.11a/g, the tolerances are presented in Section 18.3.9.7.4 of 802.11-2012 and are reproduced below:

Rate Modulation / Coding EVM (dBm)
6 Mbps BPSK 1/2 -5
6 Mbps BPSK 3/4 -8
12 Mbps QPSK 1/2 -10
18 Mbps QPSK 3/4 -13
24 Mbps 16-QAM 1/2 -16
36 Mbps 16-QAM 3/4 -19
48 Mbps 64-QAM 2/3 -22
54 Mbps 64-QAM 1/2 -25

The 802.11 standard also specifies the procedure in which similar values can be measured for WLAN devices in Section 18.3.9.8 of 802.11-2012. To perform these measurements, you need calibrated test equipment whose with measurements you can trust. We have used the Keysight N4010A Wireless Connectivity Test Set. For this test, we use the N4010A's ability to accurately measure the EVM of transmissions from the Mango 802.11 Reference Design on WARP v3. We also use the N4010A's accurate Tx power measurement to measure the accuracy of the Mango 802.11 Reference Design's Tx power parameter. The N4010A can be scripted via Ethernet, so we can write a single Python script that controls both the N4010A as well as the 802.11 Reference Design via the WLAN Experiments Framework.

Tx EVM

Tx Power Accuracy

Attachments (3)

Download all attachments as: .zip