1. RTS&CTS Exchange in wideband transmission
Month Year
doc.: IEEE yy/xxxxr0
Sep, 2010
RTS&CTS Exchange in wideband transmission
Date:
Authors:
Li Nan, ZTE Corporation
John Doe, Some Company

2. Month Year
doc.: IEEE yy/xxxxr0
Sep, 2010
Abstract
802.11ac is supposed to provide very high throughput, which requires to use wideband as much as possible.
When OBSS exists, the OBSS channel distribution and interference on Tx side might be different with that of Rx side, which is even complex when wideband is used.
The 11n OBSS protection mechanism needs extension to adapt to wideband case. A practical RTS/CTS mechanism for wideband in OBSS case is proposed in this contribution.
Li Nan, ZTE Corporation
John Doe, Some Company

3. Complex OBSS scenarios with Wideband Transmission
Sep, 2010
Complex OBSS scenarios with Wideband Transmission
WLAN devices working on 5GHz might be:
–802.11a compliant: 20MHz channels
–802.11n compliant: 20/40MHz channels
–802.11ac compliant: 20/40/80/160MHz channels
In OBSS case, the 80/160MHz BSS is very likely to affect or to be affected by neighbouring BSSs. And a responder of a transmission will probably affect or be affected by different OBSS from what the initiator does.

4. Wideband Transmission in OBSS Scenario
Month Year
doc.: IEEE yy/xxxxr0
Sep, 2010
Wideband Transmission in OBSS Scenario
Pros:
Very high throughput in data transmission.
Cons:
Fixed bandwidth: less opportunity to transmit since requesting more clean channels, which might impact guaranteed QoS.
Dynamic bandwidth: difficult tradeoff between complexity and bandwidth efficiency.
Li Nan, ZTE Corporation
John Doe, Some Company

5. Example of hidden node issues on Tx/Rx side
Month Year
doc.: IEEE yy/xxxxr0
Sep, 2010
Example of hidden node issues on Tx/Rx side
Li Nan, ZTE Corporation
John Doe, Some Company

6. Example of hidden node issues on Rx side
Sep, 2010
Example of hidden node issues on Rx side
AP1 and STA1 transmit with 80MHz channel width, while AP2 and STA2 transmit with 40MHz channel width
AP2 starts a 40MHz BSS , its primary channel is different from AP1’s.
However, transmission between AP2 and STA2 affects transmission between AP1 and STA1 because of the overlap of STA1 and STA2
And STA1 might affect STA2’s transmission when STA1 tries to reply CTSs on its secondary channels.
Li Nan, ZTE Corporation

7. Proposed RTS/CTS Extension
Sep, 2010
Proposed RTS/CTS Extension
Tx STA sends RTS(s) on all 20MHz idle channels detected by any means within operating bandwidth, including primary channel.
Rx STA responds CTS(s) on each 20MHz channel which is idle, and is indicated by received RTS or the RTS(s) has been detected on, including primary channel.
Li Nan, ZTE Corporation

8. Sep, 2010
Thank you!
Li Nan, ZTE Corporation