Changes between Version 13 and Version 14 of 802.11/Benchmarks/Tx_Char


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Timestamp:
Dec 9, 2014, 10:49:39 AM (9 years ago)
Author:
chunter
Comment:

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  • 802.11/Benchmarks/Tx_Char

    v13 v14  
    1818This table codifies the intuition that high-order modulation and coding rates are more sensitive than their low rate counterparts. Therefore, the quality requirements on the waveform are more stringent for the higher rates.
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     20
     21== Transmit EVM Test ==
     22
    2023The 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 [http://www.keysight.com/en/pd-326092-pn-N4010A/wireless-connectivity-test-set?&cc=US&lc=eng 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 [wiki:802.11/wlan_exp WLAN Experiments Framework].
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    2629The above figure shows the setup of this test. The WARP v3 kit cabled to the N4010A with 15 dB of external attenuation applied. Note: this 15dB is compensated for and is de-embedded from the below results.
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    28 == Transmit EVM ==
    29 
     31=== Methodology ===
    3032Using the WLAN Experiments Framework, we perform the following steps:
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    4345
    44 == Transmit Power Accuracy ==
     46== Transmit Power Accuracy Test ==
    4547
    46 In the previous EVM experiments, you may have noticed the label on the x-axis is "target" transmit power. This is the independent variable supplied to the [https://warpproject.org/docs/mango-wlan-exp/node.html#wlan_exp.node.WlanExpNode.set_tx_power set_tx_power wlan_exp command]. The N4010A also provides an accurate measure of actual transmit power.
     48In the previous EVM experiments, you may have noticed the label on the x-axis is "target" transmit power. This is the independent variable supplied to the [https://warpproject.org/docs/mango-wlan-exp/node.html#wlan_exp.node.WlanExpNode.set_tx_power set_tx_power wlan_exp command]. The N4010A also provides an accurate measure of actual transmit power. The methodology for this experiment is the same as the transmit EVM test. In fact, both EVM and actual transmit power can be measured simultaneously.
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    4850||  [[Image(tx_power_accuracy.png, width=800)]]  ||