Anritsu MX370111A-002, MX269028A-002, MX269028A, MX370111A User Manual

Application Note

W-LAN 802.11ac Measurement

MX269028A

Demonstration using Signal Analyzer and Vector Signal Generator

WLAN (802.11) Measurement Software

MX269028A-002

802.11ac (160 MHz) Measurement Software

MS2690A/MS2691A/MS2692A

Signal Analyzer

MG3710A

Vector Signal Generator

MX370111A

WLAN IQproducer

MX370111A-002

802.11ac (160 MHz) Option

Introduction

This application note explains the procedures for outputting an IEEE802.11ac signal from a vector signal generator and measuring the modulation accuracy and power using a signal analyzer.

The IEEE802.11ac PHY layer features 256QAM multi-level modulation compared to the IEEE802.11n PHY layer as well as both 80 MHz and 160 MHz (option) bandwidths, plus expandability for up to 8 MIMO streams.

This application note provides an understanding of the features of IEEE802.11ac through the following items:

 Generation and output of 256QAM, 80-MHz band signals and measurement of their Tx characteristics  Generation and output of 256QAM, 160-MHz band signals and measurement of their Tx characteristics  Generation and output of 8 x 8 MIMO signals and measurement of their Tx characteristics  Sending of specified number of packets from vector signal generator (mainly for Rx tests)

MX269028A/MX370111A-E-F-1-(1.00)

Preparations

RF Output

Vector Signal Generator

Signal Analyzer

RF Input

The instruments, etc., required for this demonstration are listed below.  MG3710A Vector Signal Generator (Version 2.01.00 or newer firmware and IQproducer Version 14.01 or

newer) Option-036 1stRF 100 kHz to 6 GHz Option-066 2ndRF 100 kHz to 6 GHz MX370111A WLAN IQproducer MX370111A-002 802.11ac (160 MHz) Option

 MS2690A/MS2691A/MS2692A Signal Analyzer (Version 5.05.00 or newer) MX269028A MX269028A WLAN (802.11) Measurement Software MX269028A-002 802.11ac (160MHz) Measurement Software MS2690A-077 Analysis Bandwidth Expansion 62.5 MHz (with MS2690A) MS2690A-078 Analysis Bandwidth Expansion 125 MHz (with MS2690A) MS2691A-077 Analysis Bandwidth Expansion 62.5 MHz (with MS2691A) MS2691A-078 Analysis Bandwidth Expansion 125 MHz (with MS2691A) MS2692A-077 Analysis Bandwidth Expansion 62.5 MHz (with MS2692A) MS2692A-078 Analysis Bandwidth Expansion 125 MHz (with MS2692A)

 RF Cable 1 pc

Set-up the instruments as shown below.

Fig. 1. Set-up Diagram

To simplify the operations described in this application note, the cable attenuation settings and calibration procedures are omitted. To measure more accurately, refer to the Operation Manual for the additional required procedures.

This application note references the following IEEE802.11ac standard:  IEEE P802.11ac/D2.0, January 2012

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Generating and Measuring 80-MHz Band Signals

Generating and Outputting Signals using Vector Signal Generator

IEEE802.11ac 80-MHz bandwidth, one-packet signal can be output from the MG3710A Vector Signal Generator using the following procedure.

[Procedure]

1. Execute [Preset] → [F3] Preset All.

2. Press [IQpro] to start IQproducer.

3. Select the [System (Non-Cellular)] tab.

4. Press the [WLAN] button.

5. Press the [System] button in the [Common] tab and select [11ac].

6. Press the [Bandwidth] button in the [Common] tab and select [80 MHz].

7. Press the [Number of Packets] button in the [Common] tab and select [1].

8. Press the [Repeat Count] button in the [Common] tab and select [1].

9. Select [MCS] in the [PHY] tab and set [9]. Refer to the appendix for a description of MCS.

10. Set [Package] to [WLAN_11ac] and [Pattern Name] to [80MHz_MCS9].

11. Press [Calculation & Play] at the bottom right of the screen to start waveform generation.

Select [SG1] at the dialog for choosing the SG load destination.

12. Press [SG1].

13. Press [Frequency] and set the frequency to 5.21 GHz.

14. Press [Level] and set the level to –15 dBm.

15. Turn on RF Output [Mod On/Off] and [On/Off] to output the modulation signal.

16. Press [I/Q] → [F3] Internal Channel Correction to set [On].

17. Press [I/Q] → [F6] Wideband to set [On]. The above procedure repeatedly generates and outputs 80-MHz bandwidth, single-packet signal from the

MG3710A Vector Signal Generator.

Fig. 2. Vector Signal Generator Settings (80-MHz bandwidth)

Measuring with Signal Analyzer

MX269028A/MX370111A-E-F-1-(1.00)

The IEEE802.11ac 80-MHz bandwidth signal output from the MG3710A Vector Signal Generator is measured

IEEE802.11ac

22.3.18 PMD Transmit Specification

Signal Analyzer

22.3.18.1 Transmit Spectrum Mask

[Measure] → [F7] Spectrum Emission Mask (Swept)

22.3.18.2 Spectral Flatness

[Measure] → [F1] Modulation Analysis [Trace] → [F1] Trace Mode → [F3] Spectral Flatness [F8] Spectral Flatness Type → [F1] Amplitude Flatness (Outside/Inside with Max/Min)

22.3.18.3 Transmit Center Frequency Tolerance

[Measure] → [F1] Modulation Analysis Frequency Error

22.3.18.4 Symbol Clock Frequency Tolerance

[Measure] → [F1] Modulation Analysis Symbol Clock Error

22.3.18.5.2 Transmit Center Frequency Leakage

[Measure] → [F1] Modulation Analysis Center Frequency Leakage

22.3.18.5.3 Transmitter Constellation Error

[Measure] → [F1] Modulation Analysis EVM (rms)

using the MS2690A/MS2691A/MS2692A Signal Analyzer.

(1) Measuring Modulation Accuracy

[Procedure]

1. Press [Application Switch] and select [WLAN].

2. Execute [Preset] → [F1] Preset.

3. Press [Frequency] and set the frequency to 5.21 GHz.

4. Press [Amplitude] and set the level to –15 dBm.

5. Press [Measure] → [F1] Modulation Analysis.

6. Press [F2] WLAN Standard → [ → ] (Function Menu page 2) → [F1] IEEE802.11ac.

7. Press [Measure] → [F1] Modulation Analysis → [F1] Analysis Time → [F5] Capture Length to set [1] ms.

*This parameter is adjusted according to the burst length of the signal to be measured. If the set value is too

large for the burst length, the time required for that part of the measurement is overhead.

8. Press [Measure] → [F1] Modulation Analysis → [F4] Channel Bandwidth to set [80] MHz.

9. Press [Trace] → [F3] EVM Unit to set [dB].

10. Press [Trace] → [F1] Trace Mode → [F3] Spectral Flatness. The above procedure measures the modulation accuracy such as the frequency offset, EVM, etc. The MX269028A WLAN (802.11) Measurement Software and the MX269028A-002802.11ac (160 MHz)

Measurement Software analyze the input signal PPDU (physical layer convergence procedure (PLCP) protocol data unit) by default, presuming a format based on the included training field and SIGNAL field. Consequently, if the correct information is set in the input signal PPDU, there is no need to set the signal format–other than the minimum parameters–in the above procedure.

The measurement results and their correspondence with the items specified in IEEE802.11ac are shown below.

Table 1. IEEE802.11ac (D2.0) Measurement Items and Items Displayed by Signal Analyzer

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Fig. 3. Modulation Accuracy Measurement (80-MHz bandwidth)

Fig. 4. Spectrum Mask Measurement (80-MHz band, spectrum analyzer function, sweeping method)

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