Changes between Version 4 and Version 5 of 802.11/Benchmarks/Pkt_Det_Min_Power_Char


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Timestamp:
Dec 18, 2014, 4:53:20 PM (9 years ago)
Author:
chunter
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  • 802.11/Benchmarks/Pkt_Det_Min_Power_Char

    v4 v5  
    33= Packet Detection Minimum Power Characterization =
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    5 The Mango 802.11 Reference Design has a feature to set a minimum packet detection power. By doing so, a user can specify a minimum ''required'' power that must be present before the PHY will attempt to decode a packet. This parameter can be very useful in experiments for eliminating difficult-to-reproduce low-level interference from other Wi-Fi networks. If a user knows that their devices in the experiment are close to one another, they can raise this threshold to keep their receivers from attempting to decode other distant interferers. This is not universally a good idea -- if the research question a user is trying to answer relies on the presence of weak interferers, then this feature may not be appropriate.
     5The Mango 802.11 Reference Design has a feature to set a minimum packet detection power. By doing so, a user can specify a minimum ''required'' power that must be present before the PHY will attempt to decode a packet. Raising this power requirement can make a receiver intentionally "more deaf." This parameter can be very useful in experiments for eliminating difficult-to-reproduce low-level interference from other Wi-Fi networks. If a user knows that their devices in the experiment are close to one another, they can raise this threshold to keep their receivers from attempting to decode other distant interferers. This is not universally a good idea -- if the research question a user is trying to answer relies on the presence of weak interferers, then this feature may not be appropriate.
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    77||  [[Image(setup.png, width=600)]]  ||
    … …  
    18181. Load each waveform in to the N4010A's volatile memory as segment files.
    19191. Sweep different minimum packet detection power thresholds. For each value:
    20    a. Create N4010A sequence files that send each waveform segment 1000x in a row
    21    a. Use [https://warpproject.org/docs/mango-wlan-exp/node.html#statistics-commands WLAN Experiments Statistics] to determine how many of the transmissions were fully received with a good FCS.
     20   1. Sweep Rx powers in the N4010A.
     21      a. Create N4010A sequence files that send each waveform segment 1000x in a row
     22      a. Use [https://warpproject.org/docs/mango-wlan-exp/node.html#statistics-commands WLAN Experiments Statistics] to determine how many of the transmissions were fully received with a good FCS.
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    2425== Results ==
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     27Each tuple of (Rx Power, Minimum Packet Detection Power) produces some measurable packet error rate (PER). Using wlan_exp, we have traces a fixed PER through this (Rx Power, Minimum Packet Detection Power) space.
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    3129||  [[Image(rx_pkt_det_min_power.png, width=800)]]  ||
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     31The above figure shows a 10% PER curve and a 1% PER curve as a function of minimum packet detection power. In the leftmost region of the plot where the PER curves "flatten out," the PER of the link is dominated by noise. In other words, the minimum packet detection power is set at powers lower than the PHY can receive a packet anyway. At a certain point, an increased minimum packet detection power does begin to affect reception because packets received weaker than that threshold are ignored. As such, the PER curve increases with a slope of 1dB per dB.
     32
     33The 1% PER curve is plotted alongside the 10% PER curve in order to demonstrate