1. Enterprise Simulation Scenario
September 2009
doc.: IEEE /816r5
Sept. 2009
Enterprise Simulation Scenario
Date:
Brian Hart (Cisco)
Hart (Cisco)

2. Improvements to the enterprise simulation scenario
September 2009
doc.: IEEE /816r5
Sept. 2009
Improvements to the enterprise simulation scenario
Situation
11ac has 5 or 6 channels at 5GHz whereas 11n had 12 channels. Overlapping APs are much more likely with 5 or 6 channels.
The Functional Requirements and Evaluation Methodology 09/451r7 includes:
“Note) It is encouraged that TGac technology proposals describe its impact on OBSS”
Complication
This Note will lead to un-comparable qualitative comments.
In San Francisco we straw-polled a specific change that would modify the Note to make it more quantitative, with results Y34, N0, A30
This is a large number of Abstains
During a TGac we solicited doubts and questions re the specific change, and proposed a compromise change in 09/980r0
Key Line
We bring the topic to a motion
Brian Hart (Cisco)
Hart (Cisco)

3. There are only five or six 80 MHz channels
September 2009
doc.: IEEE /816r5
Sept. 2009
There are only five or six 80 MHz channels
There are five 80MHz channels at 5 GHz
36-48, 52-64, , ,
Plus a sixth, , with a regulatory change
Typical channel plan with six channels is:
Brian Hart (Cisco)
Hart (Cisco)

4. So we expect two overlapping BSSs
September 2009
doc.: IEEE /816r5
Sept. 2009
So we expect two overlapping BSSs
APs co-channel with the (0,0) AP are at
(-20,-40), (20,40)m [44m range]
(-40,40), (40,40)m [57m range]
(0,60), (-60,0)m [60m range]
Now range with -76dBm CCA (for 80MHz) is 50m:
17dBm + 3dBi - 47dB[1m] - 20log10(5m/1m) - 35log10(50m/5m) = -76dBm
With multistorey deployments, 20dBm TX power, 6dBi antennas, cubes, realistic sensitivities, 10 or 20m breakpoint, the actual overlap is worse
But let’s assume 2 overlapping BSSs for simplicity
Brian Hart (Cisco)
Hart (Cisco)

5. Proposal: let’s allow comparability in OBSS behavior
September 2009
doc.: IEEE /816r5
Sept. 2009
Proposal: let’s allow comparability in OBSS behavior
Uplink/downlink MU-MIMO / SDMA and OFDMA are valuable technologies that we should be exploring, yet they are more challenging in an OBSS world
We should include OBSS as an “impairment” because otherwise there is a risk we will make suboptimal design choices based on false optimism: i.e.
2 simulation scenarios, with & without OBSS, so they are directly comparable
minimize #stations to simulate (33 total)
a compromise between homogeneous BSSs versus 1 client in the OBSSs, proposed as 20/5/5 clients for the 3 BSSs
40 MHz 11ac APs are further apart than 80 MHz 11ac APs
one OBSS is a legacy 20/40 MHz 11n AP
both 11ac BSSs have the same bandwidth (40 or 80)
BSS distances are provided
Brian Hart (Cisco)
Hart (Cisco)

6. Proposed Motion Motion:
September 2009
doc.: IEEE /816r5
Sept. 2009
Proposed Motion
Motion:
TGac approves applying the changes in 09/980r1 to 09/451 for the purpose of allowing comparability in OBSS behavior
Moved:
Seconded:
Result: Y/N/A
Brian Hart (Cisco)
Hart (Cisco)

7. Soliciting Doubts and Questions
September 2009
doc.: IEEE /816r5
Sept. 2009
Soliciting Doubts and Questions ?
Brian Hart (Cisco)
Hart (Cisco)