Changes between Version 9 and Version 10 of 802.11/Benchmarks/Rx_Char


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Timestamp:
Jan 15, 2018, 2:28:54 PM (4 years ago)
Author:
chunter
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  • 802.11/Benchmarks/Rx_Char

    v9 v10  
    33= Receiver Characterization =
    44
    5 The IEEE 802.11 Standard specifies a minimum receiver sensitivity that all 802.11 devices must achieve. This sensitivity is specified as a receive power (in dBm) in which a device must achieve no worse than a 10% packet-error-rate (PER) for PPDU receptions of 1000 octets. The receiver minimum input sensitivity requirements are specified in Section 18.3.10.2 of 802.11-2012 and are reproduced here:
     5The IEEE 802.11 Standard specifies a minimum receiver sensitivity that all 802.11 devices must achieve. For DSSS waveforms, this sensitivty is specified as a receive power (in dBm) in which a device must achieve no worse than a 8% packet-error-rate (PER) for an MPDU lenght of 1024 octets. For OFDM waveforms (NONHT and HTMF), minimum receiver sensitivity is specified with the criteria of no more than 10% PER with a length of 1000 octets. The receiver minimum input sensitivity requirements can be found in the following locations of the 802.11-2016 standard:
    66
    7 ||=  Rate  =||=  Modulation / Coding  =||=  Minimum Sensitivity (dBm)  =||
    8 ||  6 Mbps  ||  BPSK 1/2  ||  -82  ||
    9 ||  9 Mbps  ||  BPSK 3/4  ||  -81  ||
    10 ||  12 Mbps  ||  QPSK 1/2  ||  -79  ||
    11 ||  18 Mbps  ||  QPSK 3/4  ||  -77  ||
    12 ||  24 Mbps  ||  16-QAM 1/2  ||  -74  ||
    13 ||  36 Mbps  ||  16-QAM 3/4  ||  -70  ||
    14 ||  48 Mbps  ||  64-QAM 1/2  ||  -66  ||
    15 ||  54 Mbps  ||  64-QAM 2/3  ||  -65  ||
     7* DSSS waveforms in 15.4.6.2
     8* NONHT waveforms in Section 17.3.10.2
     9* HTMF waveforms in Section 19.3.19.1
    1610
    17 The values specified in this table recognize that higher rate transmissions require higher SNR (and therefore higher delivered power) than lower rate transmissions.
     11== Methodology ==
    1812
    19 == Receiver Sensitivity Test ==
     13=== DSSS Experiments ===
     14A DSSS transmitter was created using the [wiki:WARPLab WARPLab Framework]. This design transmits 1Mbps or 2Mbps DSSS waveforms at regular intervals. Independently, an 802.11 Reference Design receiver was used to measure the number of received DSSS frames at various receive powers. This node was controlled using the [wiki:802.11/wlan_exp wlan_exp Experiments Framework] and the number of receptions were calculated using the [wiki:802.11/wlan_exp/log event log]. The receive power independent variable was controlled with a programmable attenuator and was verified with a [https://www.tek.com/spectrum-analyzer/rsa306 Tektronix RSA306B Spectrum Analyzer].
    2015
    21 To test the Mango 802.11 Reference Design Rx PHY against these measures, we use the [http://www.keysight.com/en/pd-326092-pn-N4010A/wireless-connectivity-test-set?&cc=US&lc=eng Keysight N4010A Wireless Connectivity Test Set] to generate known-good 1000 octet transmissions and deliver those transmissions to WARP v3 at a specified power. Then, we use the [wiki:802.11/wlan_exp WLAN Experiments Framework] to measure PER.
     16=== OFDM Experiments ===
     17The 802.11 Reference Design is able to transmit NONHT and HTMF OFDM waveforms natively. The only difference in methodology between the DSSS and OFDM Rx sensitivity experiments is that the OFDM experiments are able to use the 802.11 Reference Design on the transmit node with the [wiki:802.11/MAC/Upper/MACHighFramework/LTG Local Traffic Generator].
    2218
    23 ||  [[Image(setup.png, width=600)]]  ||
    24 ||  '''Experimental Setup'''  ||
     19== Results Summary ==
     20
     21=== DSSS Waveform ===
     22||=  Rate  =||=  Modulation  =||=  Minimum Sensitivity (dBm)  =||=  '''Achieved Sensitivity (dBm)'''  =||=  '''Improvement over Minimum (dB)'''  =||
     23||  1 Mbps  ||  DBPSK  ||  n/a  ||  '''-92'''  ||  n/a  ||
     24||  2 Mbps  ||  DQPSK  ||  -80  ||  '''-87'''  ||  '''7'''  ||
     25
     26=== NONHT Waveform ===
     27||=  Rate  =||=  Modulation / Coding  =||=  Minimum Sensitivity (dBm)  =||=  '''Achieved Sensitivity (dBm)'''  =||=  '''Improvement over Minimum (dB)'''  =||
     28||  6 Mbps  ||  BPSK 1/2  ||  -82  ||  '''-88'''  ||  '''6'''  ||
     29||  9 Mbps  ||  BPSK 3/4  ||  -81  ||  '''-88'''  ||  '''7'''  ||
     30||  12 Mbps  ||  QPSK 1/2  ||  -79  ||  '''-87'''  ||  '''8'''  ||
     31||  18 Mbps  ||  QPSK 3/4  ||  -77  ||  '''-84'''  ||  '''7'''  ||
     32||  24 Mbps  ||  16-QAM 1/2  ||  -74  ||  '''-83'''  ||  '''9'''  ||
     33||  36 Mbps  ||  16-QAM 3/4  ||  -70  ||  '''-77'''  ||  '''7'''  ||
     34||  48 Mbps  ||  64-QAM 1/2  ||  -66  ||  '''-74'''  ||  '''8'''  ||
     35||  54 Mbps  ||  64-QAM 2/3  ||  -65  ||  '''-72'''  ||  '''7'''  ||
     36
     37=== HTMF Waveform ===
     38||=  Rate  =||=  Modulation / Coding  =||=  Minimum Sensitivity (dBm)  =||=  '''Achieved Sensitivity (dBm)'''  =||=  '''Improvement over Minimum (dB)'''  =||
     39||  6.5 Mbps  ||  BPSK 1/2  ||  -82  ||  '''-87'''  ||  '''5'''  ||
     40||  13 Mbps  ||  QPSK 1/2  ||  -79  ||  '''-85'''  ||  '''6'''  ||
     41||  19.5 Mbps  ||  QPSK 3/4  ||  -77  ||  '''-83'''  ||  '''6'''  ||
     42||  26 Mbps  ||  16-QAM 1/2  ||  -74  ||  '''-81'''  ||  '''6'''  ||
     43||  39 Mbps  ||  16-QAM 3/4  ||  -70  ||  '''-76'''  ||  '''6'''  ||
     44||  52 Mbps  ||  64-QAM 2/3  ||  -66  ||  '''-72'''  ||  '''6'''  ||
     45||  58.5 Mbps  ||  64-QAM 3/4  ||  -65  ||  '''-71'''  ||  '''6'''  ||
     46||  65 Mbps  ||  64-QAM 5/6  ||  -64  ||  '''-67'''  ||  '''3'''  ||
     47
     48== Detailed Results ==
     49
     50=== DSSS Waveform ===
     51
     52||  [[Image(dsss_sensitivity.png, width=600)]]  ||
     53||  '''DSSS Rx Sensitivity'''  ||
    2554
    2655
    27 === Methodology ===
    28 1. Construct PPDU waveforms in MATLAB for each PHY rate that have the following characteristics:
    29   a. 1000 octet PPDU length (i.e., a 972 byte payload + 14 byte MAC header + 4 byte FCS)
    30   a. 10 different scrambling sequence start points to generate waveforms with different peak-to-average-power (PAPR) features
    31 1. Load each waveform in to the N4010A's volatile memory as segment files.
    32 1. Create N4010A sequence files that send each waveform segment 1000x in a row
    33 1. 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.
     56=== NONHT Waveform ===
    3457
    35 We have used the above steps determine the Mango 802.11 Reference Design's receive sensitivity across 7 different WARP v3 kits and RF interfaces.
     58||  [[Image(rx_sensitivity_nonht.png, width=600)]]  ||
     59||  '''NONHT Rx Sensitivity'''  ||
    3660
    37 ||  [[Image(rx_sensitivity.png, width=800)]]  ||
     61=== HTMF Waveform ===
    3862
    39 The above plots shows the results of this experiment. In particular, notice the receive powers that cross the 10% PER horizontal line -- these can be compared directly to the minimum sensitivity values specified by the standard. Specifically,
     63||  [[Image(rx_sensitivity_htmf.png, width=600)]]  ||
     64||  '''HTMF Rx Sensitivity'''  ||
    4065
    41 ||=  Rate  =||=  Modulation / Coding  =||=  Minimum Sensitivity (dBm)  =||=  '''Mango 802.11 Sensitivity (dBm)'''  =||=  '''Difference'''  =||
    42 ||  6 Mbps  ||  BPSK 1/2  ||  -82  ||  '''-85'''  ||  '''3dB better than minimum'''  ||
    43 ||  9 Mbps  ||  BPSK 3/4  ||  -81  ||  '''-83'''  ||  '''2dB better than minimum'''  ||
    44 ||  12 Mbps  ||  QPSK 1/2  ||  -79  ||  '''-83'''  ||  '''4dB better than minimum'''  ||
    45 ||  18 Mbps  ||  QPSK 3/4  ||  -77  ||  '''-81'''  ||  '''4dB better than minimum'''  ||
    46 ||  24 Mbps  ||  16-QAM 1/2  ||  -74  ||  '''-78'''  ||  '''4dB better than minimum'''  ||
    47 ||  36 Mbps  ||  16-QAM 3/4  ||  -70  ||  '''-75'''  ||  '''5dB better than minimum'''  ||
    48 ||  48 Mbps  ||  64-QAM 1/2  ||  -66  ||  '''-71'''  ||  '''5dB better than minimum'''  ||
    49 ||  54 Mbps  ||  64-QAM 2/3  ||  -65  ||  '''-69'''  ||  '''4dB better than minimum'''  ||
    5066
    5167== Rx Power Accuracy ==
    5268
    53 Because the N4010A lets us accurately specify a power level at which a transmission is delivered to the antenna port of WARP v3, we can also test the Mango 802.11 Reference Design's ability to estimate receive power from the transceivers RSSI circuit.
     69To determine the accuracy of the RSSI to Rx power mapping in the 802.11 Reference Design, we use the [http://www.keysight.com/en/pd-326092-pn-N4010A/wireless-connectivity-test-set?&cc=US&lc=eng Keysight N4010A Wireless Connectivity Test Set]. The N4010A lets us accurately specify a power level at which a transmission is delivered to the antenna port of WARP v3 and we can use this to compare against the receive power calculated by the 802.11 Reference Design.
    5470
    5571||  [[Image(rx_power_accuracy.png, width=800)]]  ||