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#1 2018-Dec-06 13:22:48

Yan Wang
Member
Registered: 2018-Oct-25
Posts: 10

802.11 Reference Design

Hello,

I have a question when I use the Matlab to display the rx_pwr with rx_timestampe. The data is extracted from the log file. Only let the AP send the data to STA and STA can send ACK to AP.  I keep moving the ap at a slow speed when executing the experiment. As can be seen in the figure, the data are not continuous, why this would happen?


https://upload.cc/i1/2018/12/07/mYMZX4.png

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#2 2018-Dec-06 13:43:56

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5005

Re: 802.11 Reference Design

This plot does not provide enough information to understand the traffic in your experiment. You will need to analyze the log data more carefully to understand the results.

A few things to consider:
-Over-the-air experiments are inherently unpredictable, especially in the presence of interference and varying channel conditions

-The RX_OFDM['timestamp'] field uses the node's MAC Time. The AP's MAC Time is a free-running microsecond counter. The STA's MAC Time a microsecond counter that runs freely but is updated every time it receives a beacon from the AP. Depending on whether the STA's oscillator is faster or slower than the AP, these timestamp updates can create gaps/overlaps in Rx-vs-time analyses. You may consider disabling this functionality with n_sta.enable_beacon_mac_time_update(false).

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#3 2018-Dec-07 04:30:49

Yan Wang
Member
Registered: 2018-Oct-25
Posts: 10

Re: 802.11 Reference Design

murphpo wrote:

-The RX_OFDM['timestamp'] field uses the node's MAC Time. The AP's MAC Time is a free-running microsecond counter. The STA's MAC Time a microsecond counter that runs freely but is updated every time it receives a beacon from the AP. Depending on whether the STA's oscillator is faster or slower than the AP, these timestamp updates can create gaps/overlaps in Rx-vs-time analyses. You may consider disabling this functionality with n_sta.enable_beacon_mac_time_update(false).

I am sorry that I am a python newer. How and where can I add "n_sta.enable_beacon_mac_time_update(false)" to the log_capture_two_node_two_flow.py to disable the sta's functionality?

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#4 2018-Dec-07 09:19:16

murphpo
Administrator
From: Mango Communications
Registered: 2006-Jul-03
Posts: 5005

Re: 802.11 Reference Design

I would suggest adding that call after n_ap.add_association().

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