1. 2.4 GHz 20/40MHz Coexistence Survey of Channels
May 2006
doc.: IEEE /0xxxr0
May 2006
2.4 GHz 20/40MHz Coexistence Survey of Channels
Date:
Authors:
Jason Trachewsky, Matthew Fischer (Broadcom)
Jason Trachewsky, Matthew Fischer (Broadcom)

2. Informal Survey Locations
May 2006
Informal Survey Locations
Country
State
Number of APs
USA MA 1 NH 3 NC 4 IL CA 41 UK 5
Japan
Taiwan 8
Germany
Korea
Sweden 2
The Netherlands
France 6
Jason Trachewsky, Matthew Fischer (Broadcom)

3. Informal World-Wide Survey of APs
May 2006
Informal World-Wide Survey of APs
Most APs are on chs. 1, 6 and 11.
However roughly 25% are located on “other” channels.
Jason Trachewsky, Matthew Fischer (Broadcom)

4. Minimum Channel Separations
May 2006
doc.: IEEE /0xxxr0
May 2006
Minimum Channel Separations
The distribution of minimum channel separations between APs in each location shows that “individuals” (those not using 1, 6, or 11) are scattered widely across locations. One is likely to encounter usage of the “other” channels.
Jason Trachewsky, Matthew Fischer (Broadcom)
Jason Trachewsky, Matthew Fischer (Broadcom)

5. May 2006
Concluding Remarks
25 MHz separation between the control and extension channels does not solve the MHz coexistence problem.
For the CCA using frame detect (CS) to properly work, both control and extension channels have to overlap with channels used in the 2.4 GHz band. Overlap is not guaranteed based on the survey results presented here.
Energy Detect (ED) CCA on the extension channel seems to be a reasonable solution.
Jason Trachewsky, Matthew Fischer (Broadcom)