1. Interference Analysis for Residential Environments
September 2006
doc.: IEEE /1458r0
Nov 2008
Interference Analysis for Residential Environments
Date:
Authors:
Rangarajan et al (Cisco)
Joonsuk Kim, Broadcom Corp.

2. Overview Simulation parameters
September 2006
doc.: IEEE /1458r0
Overview
Simulation parameters
Interconnectedness of APs in 700 sq. ft. apartment complex
Interconnectedness of APs in 1400 sq. ft. apartment complex
Conclusions
Joonsuk Kim, Broadcom Corp.

3. Typical AP layout in residential location
September 2006
doc.: IEEE /1458r0
Typical AP layout in residential location
Each floor shown in different color
Pool
Distance (m)
Joonsuk Kim, Broadcom Corp.

4. Model parameters Nov 2008 Simulated Typical range
AP density (approx apartment size)
700 sq. ft.
1400 sq. ft.
500 … 8000 sq. ft.
Transmit power
15 dBm
15 … 20 dBm
Transmit & receive gain (ea.)
2 dB
2 … 6 dB
Pathloss at 1m
47 dB (5 GHz)
40 … 47 dB (2.4/5 GHz)
PLE
3.5
Interfloor attenuation
10 dB
10 … 15 dB
Shadowing
7 dB
5 … 7 dB
#Channels
12 (5 GHz; 40 MHz)
3 … 24 (2.4/5 GHz, 20 MHz)
Sensitivity
- 82 dBm
<- 90 … -82 dBm
Rangarajan et al (Cisco)

5. Graph of APs hearing others in the same channel – Channel Number “6”
Nov 2008
Graph of APs hearing others in the same channel – Channel Number “6”
Rangarajan et al (Cisco)

6. Graph of APs hearing others in the same channel – Channel Number “4”
Nov 2008
Graph of APs hearing others in the same channel – Channel Number “4”
Rangarajan et al (Cisco)

7. Graph of APs hearing others in the same channel – Channel Number “1”
Nov 2008
Graph of APs hearing others in the same channel – Channel Number “1”
Rangarajan et al (Cisco)

8. Mean number of co-channel APs heard above particular RSSI
Nov 2008
Mean number of co-channel APs heard above particular RSSI
Rangarajan et al (Cisco)

9. Now double the size of apartments. One AP every 1400sq. ft.
Nov 2008
Now double the size of apartments. One AP every 1400sq. ft.
Now things seems slightly more localized
Rangarajan et al (Cisco)

10. Now double the size of apartments. One AP every 1400sq. ft. (2)
Nov 2008
Now double the size of apartments. One AP every 1400sq. ft. (2)
Now fewer co-channel APs heard above a given RSSI
Rangarajan et al (Cisco)

11. September 2006
doc.: IEEE /1458r0
Conclusions
The general problem, and the significant problem, is to address OBSS in the presence of extended multiple-hop connections
Under the (standard) simulation model with 700 sq. ft. apartments, even at 5 GHz/40 MHz, we observe extended multiple-hop connections
These connections are much more localized with 1400 sq. ft. apartments
Yet arguably the simulation model is conservative: we could plausibly increase the link budget by as much as 5 + 2*4 + 8 = 21 dB!
Or stack apartments more densely as per high density city architecture
Joonsuk Kim, Broadcom Corp.