1. Effect of CCA in residential scenario part 2
May 2013
Sept 2014
Effect of CCA in residential scenario part 2
Date:
Authors:
Osama Aboul-Magd (Huawei Technologies)

2. September 2014
Indroduction
Multiple IEEE presentations have looked at the effects of CCA levels
Several presentations have noted that higher CCAs have higher mean and 5% tputs than lower CCAs
Note: Baselines of both CCA = -82 and CCA= -92 have been used
At the June IEEE meeting, we presented results for various CCA levels using a reuse 1 residential scneario
document
We found that higher CCA levels were often harmful for the 5% point
In this presentation we look at the residential scenario for reuse 3 and 6
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3. Simulation Setting I September 2014 Residential Scenario
Example of one drop
Residential Scenario
IEEE residential scenario baseline
Less apartments modelled for faster run times
Expect conclusions will not change
2x5x3 apartments
30 APs
150 STAs (5 STAs per AP)
Pathloss as specified in 11ax Simulation Scenarios document
Reuse-3: 3x80 MHz channel
Reuse-6: 6x40MHz channel
Note: all results are generated by simulating 80MHz BSS and then are appropriately scaled
Results averaged over multiple random drops of APs and STAs locations
Floor 1
Floor 2
Floor 3
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4. Simulation Setting II September 2014 Simulation Details:
UL only Data traffic (+ DL ACKs)
Full buffer UDP
Default Tx Power: 20 dBm per antenna (AP), 15 dBm ( STA)
Antenna Gain: 0 dBi APs, -2dBi STAs
Rate Control:
MCS per link chosen to maximize long term goodput
MAC modelling
MAC is fully modelled
Deferral according to 11ah CCA rules
OBSS packets deferral only if RSSI > ED (assume BSS ID (color) in PPDU
ED level controls deferral on a network level
Nodes on the same 80 MHz channel have the same primary channel
PHY modelling
Pathloss, shadowing, (pathloss as in SS document, shadowning w sd 5dB)
no fading.
Long term PER curves based on AWGN
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5. Reuse 3 (Three channels: Red, Blue and Green)
September 2014
Reuse 3 (Three channels: Red, Blue and Green)
Channel Coloring:
No two APs that have the same channel share a floor/wall
For each AP, there are no more than 3 other APs that have the same channel and are within 2 (wall/floor)s penetration.
Red Channel
AP = [2,5,8,10,13,16,19,21,24,27]
Blue Channel
AP = [0,3,6,9 ,11,14,17,22,25,28]
Green Channel
AP = [1,4,7,12,15,18,20,23,26,29] 2 5 8 10 13 16 19 21 24 27 3 6 9 11 14 17 22 25 28 1 4 7 12 15 18 20 26 23 29
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6. Reuse 3 results September 2014 5%ile Mean 3x improvements vs -92dBm
UL 5 STAs per AP
5%ile
3x improvements vs -92dBm
4x improvements vs -82dBm
Mean
30% increase vs CCA=-92 to CCA= anything higher.
No gain compared to -82dBm
CCA
5%tile
50%tile
90%tile
mean
-52
1.58
35.61
78.82
38.72
-62
2.75
34.60
74.80
38.52
-72
3.88
36.44
82.21
39.79
-82
0.84
30.09
84.02
39.22
-92
1.21
18.23
80.03
29.57
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7. Reuse 6 (Six channels: Red, Blue, Yellow, Purple, Green and Gray)
September 2014
Reuse 6 (Six channels: Red, Blue, Yellow, Purple, Green and Gray)
Channel Coloring:
No two APs that have the same channel are within two floors/walls penetration
Red Channel
AP = [6,9,10,13,27]
Blue Channel
AP = [1,4,17,20,23]
Green Channel
AP = [0,3,16,19,22]
Yellow Channel
AP = [2,15,18,21,24]
Purple Channel
AP = [5,8,12,26,29]
Gray Channel
AP = [7,11,14,25,28]
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8. Reuse 6 results September 2014 5%ile point maximized at -82
UL 5 STAs per AP
5%ile point maximized at -82
4x lower at CCA= -92
Mean: no difference
CCA 5%
50%
90%
mean
-52
10.54
28.12
50.76
30.03
-62
10.34
27.50
51.86
29.80
-72
11.37
29.56
49.19
30.54
-82
12.49
29.49
49.25
30.73
-92
3.54
26.96
56.75
29.67
6 40 MHz channels
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9. September 2014
Conclusions
For residential scenario reuse 1:
Increasing CCA can be harmful for the 5% throughput (from )
For residential scenario reuse 3:
Gain depends on what is assumed as baseline
5%ile 3x improvements vs -92dBm; 4x improvements vs -82dBm
Mean: 30% increase vs CCA=-92 to CCA= anything higher; No gain compared to -82dBm
For residential scenario reuse 6
Negligible to small gains by increasing CCA
All CCA levels have good reuse
Effects of changing the CCA levels is highly scenario parameters dependent
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