WLAN IEEE 802.11ad RF PHY layer testing

This tutorial section on WLAN-11ad basics covers following sub topics:
Main page  11ad PHY Layer  11ad conformance tests  11ac conformance  11n vs 11ac vs 11ad 

This page on WLAN IEEE 802.11ad covers RF PHY layer testing as per 11ad standard. It covers 11ad transmitter and receiver radio conformance tests. These tests are useful for test and measurements related to 802.11ad products.

Following table-1 describes generic RF measurement test requirements. These test requirements are independent of 802.11ad physical layer used in the 11ad device. The tests include 11ad transmit mask, RF Center frequency tolerance, symbol Clock Tolerance, RF center frequency leakage and transmit ramp up and transmit rampdown time.

Specifications 11ad device support
Transmit mask As we know 11ad transmissions use ISM frequency band, inspite of this transmissions should be limited to certain magnitude of power to avoid interference among multiple 11ad devices. The radiations should be as per spectrum mask defined.
RF Center frequency tolerance Mamimum deviation of +/-20 ppm is allowed. EXAMPLE: +/- 3024Hz is allowed for channel-2. Moreover RF Center frequency should converge to about 1ppm of nominal frequency in time duration of 0.9 µs.
Symbol Clock Tolerance Maximum of +/-20 ppm is allowed.
RF center frequency leakage It should be less than -23 dB relative to total power(single carrier PHY)
It should be less than 2.5dB relative to the power of subcarrier(OFDM PHY)
Transmit ramp up and transmit rampdown time Both ramp up and ramp down times(from 10 % to 90%) should be less than 10ns

Following are physical layer 11ad test requirements. It includes transmitter EVM, Receiver sensitivity and transmit spectrum flatness. Refer EVM basics and PHY measurements for more.

As mentioned in 802.11ad tutorial there are three physical layer modes in 802.11ad. They are Control, Single carrier and OFDM. The modulation coding rates(MCS) are 0 for Control, 1 to 24 for single carrier(including low power SC) and 25 to 31 for OFDM PHY. The EVM and receiver sensitivity requirements for these different MCSs are listed below in table-2.

MCS type EVM receiver sensitivity
0 -6 -78
1 -6 -68
2 -7 -66
3 -9 -64
4 -10 -64
5 -12 -62
6 -11 -63
7 -12 -62
8 -13 -61
9 -15 -59
10 -19 -55
11 -20 -54
12 -21 -53
13 -7 -66
14 -9 -64
15 -10 -63
16 -11 -62
17 -13 -60
18 -15 -58
19 -17 -56
20 -19 -54
21 -20 -53
22 -22 -51
23 -24 -49
24 -26 -47
25 - -64
26 - -60
27 - -57
28 - -57
29 - -57
30 - -57
31 - -57

OFDM Transmit spectrum flatness:
Following are the requirements for different subcarriers:
For Subcarriers from -146 to -2 and from +2 to +146 : tolerance allowed is +/- 2dB
For Subcarriers from -177 to -147 and from +147 to +177 : tolerance allowed is +2/-4 dB

RF PHY layer conformance testing solutions

Following test and measurement products are ideal for conformance testing of 802.11ad products. Following instruments from Keysight technologies(previously known as Agilent) and R&S are very useful for 11ad device testing and measurements. These RF and baseband instruments are ideal for 11ad RF/PHY conformance testing.

Company Instrument with model number
Keysight Technologies(Agilent) N5152A 60GHz Up converter
N1999A 60GHz Down converter
M8190A Arbitrary waveform generator(AWG)
N5183A-520 MXG microwave signal generator
8267D Vector Signal Generator(VSG)
89600 VSA software
DSO-X91604A oscilloscope
DSA-X91604A Digital Signal analyzer
R&S R&S®FSU spectrum analyzer
R&S® ZVA vector network analyzer
R&S®FS-Z60,-Z75,-Z90,-Z110 harmonic mixers
R&S®ZVA-Z millimeter wave converters
R&S®NRP-Z58 thermanl power sensor
R&S®SMZ frequency multiplier
R&S®SMF100A microwave signal generator

802.11ad Related resources

WLAN 802.11ad technology features
802.11ad basic tutorial
802.11ad Physical Layer

Test and Measurement Related Links

Test and Measurement Signal Generator Companies
Test and Measurement Signal Analyzer Companies
Physical layer measurements
Production tests on RF and SoC devices
RF measurements tutorial
Testing and certification facility providers
EMI and EMC solution providers
Comparison between R&S CMU200 versus Agilent 8960 wireless test equipments

RF and Wireless Terminologies