1. Off-channel selection
March 2008
doc.: IEEE /0267r0
March 2008
Off-channel selection
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Guiming Shu,Huawei

2. March 2008
doc.: IEEE /0267r0
March 2008
Background（1/2）
In the TDLS draft 0.1, off-channel is determined by the STA which initiates TDLS procedure.
Once off-channel is determined, it is sent to the peer STA by initiator STA in TDLS-Setup-Confirm message, and then the off-channel will be the same in the whole TDLS life.
Guiming Shu,Huawei

3. Background（2/2） March 2008 March 2008 doc.: IEEE 802.11-08/0267r0
Guiming Shu,Huawei

4. March 2008
Problems
Off-channel is selected at the start of DL setup procedure, it may be not the best one when channel switching happens .
When the DL channel need to be switched from base-channel to off-channel , if STA finds that the prior selected off-channel is not suitable for use, the two STAs have no way to negotiate another off-channel.
Guiming Shu,Huawei

5. March 2008
Solution
As an amendment for current method, we suggest that an off-channel list is included in Channel_Switch_ Request message. The order of the off-channel in the list presents the priority to be selected.
The peer STA can select the best channel from the off-channel list and informs the initiator STA in Channel_Switch_ Response message.
Guiming Shu,Huawei

6. Amendment for TDLS_Channel_Switch message(1/2)
March 2008
Amendment for TDLS_Channel_Switch message(1/2)
TDLS Channel Switch Request frame format
The format of the TDLS Channel Switch Request frame contains the information shown in Table z10.
Table z10—Information for TDLS Channel Switch Request frame
Order
Information
Notes 1
Target Channel
1-octet field which contains an integer which is set to 0 to indicate the base channel and set to 1 to indicate the off-channel. 2
Off-channel list
N*2-octet field which specifies the off-channel list selected by initiator STA 。
The TDLS Channel Switch Response frame shall be sent over the direct path.
Guiming Shu,Huawei

7. Amendment for TDLS_Channel_Switch message(2/2)
March 2008
doc.: IEEE /0267r0
March 2008
Amendment for TDLS_Channel_Switch message(2/2)
TDLS Channel Switch Response frame format
The TDLS Channel Switch Request frame contains the information shown in Table z11.
Table z11—Information for TDLS Channel Switch Response frame
Order
Information
Notes 1
Result Code
1-octet field which contains an integer which is set to 0 to indicate that the switch request is accepted and set to 1 if the switch request is rejected. 2
Off-channel
2-octet field which specifies the off-channel selected by peer STA.
The TDLS Channel Switch Response frame shall be sent over the direct path.
Guiming Shu,Huawei

8. END March 2008 March 2008 doc.: IEEE 802.11-08/0267r0
Guiming Shu,Huawei