ERP Protection in IEEE 802.11s Mesh Network

1. ERP Protection in IEEE 802.11s Mesh Network Authors: Date: 2009-01-14 Ashish Shukla, Marvell Semiconductor

2. ERP Protection in Mesh Network • A Mesh Network may include NonERP Mesh STA in MBSS and or may overlap with other BSSs containing NonERP STAs. • ERP IE’s Use_Protection, NonERP_Present and Barker_Preamble_Mode bits definitions are not clear (missing) for Mesh STA. • It is not clear in 802.11s how to achieve ERP protection in Mesh Network? Ashish Shukla, Marvell Semiconductor

3. ERP Protection in Mesh Network (Proposals) • Include ERP IE in mesh beacon and Peer Link Management Action frame. • Solution 1: • Extend the definition of ERP IE in clause 7.3.2.13 as follows. • The NonERP_Present and Use_Protection bits shall be set to 1 when a one hop NonERP Mesh STA establishes peer link with this Mesh STA transmitting ERP IE. • The Use_Protection bit may be additionally set to 1, but not limited to, when • Mesh STA detects overlapped presence of either of NonERP BSS, NonERP IBSS, or NonERP MBSS. • A beacon frame is received from Mesh STA where the supported rate set contains only clause 15 or clause 18 rates. • A management frame (excluding probe request) is received where the supported rate set includes only clause 15 or clause 18 rates. • ERP mesh STAs shall invoke the use of a protection mechanism after transmission of the Use_Protection bit with a value of 1 in an MMPDU. ERP mesh STAs may additionally invoke protection mechanism use at other times. NOTE: Mesh STA doesn't have to protect ERP transmission after reception of mesh beacon with Use_Protection bit set to 1. Ashish Shukla, Marvell Semiconductor

4. ERP Protection in Mesh Network (Proposals) Cont’d • Solution 1 (cont’d) : • Extend the definition of ERP IE in clause 7.3.2.13 as follows (cont’d). • The Barker_Preamble_mode bit shall be set to 1 if there is a one hop NonERP Mesh STA neighbor that that does not support short preamble and has established peer link with this Mesh STA transmitting ERP IE. Ashish Shukla, Marvell Semiconductor

5. ERP Protection in Mesh Network (Proposals) Cont’d • Solution 2: • The Use_Protection and NonERP_Present bits shall be reserved for mesh STA. • A Mesh STA shall protect ERP transmissions in any of the following conditions : • Mesh STA received AP STA or IBSS Beacon where both use_protection and NonERP_present bit were set to 1. • Mesh STA received a management frame (excluding beacon and probe request ) where the support rate set contains only class 15 or class 18 rate. • Mesh STA received IBSS beacon where the supported rate support rate set contains only class 15 or class 18 rate. • NonERP Mesh STA establishes peer link with this mesh STA. • Mesh beacon is heard from NonERP Mesh STA. • Mesh STA may protect ERP transmissions at other times outside the scope of this standard. Ashish Shukla, Marvell Semiconductor

6. ERP Protection in Mesh Network (Proposals) Cont’d • Solution 3: • Similar to solution 1 with the following addition • ERP mesh STAs shall invoke the use of a protection mechanism after transmission or reception of the Use_Protection bit with a value of 1 in an MMPDU. ERP mesh STAs may additionally invoke protection mechanism use at other times. NOTE: Mesh STA would protect ERP transmission after transmission or reception of mesh beacon with Use_Protection bit set to 1. Ashish Shukla, Marvell Semiconductor

7. ERP Protection in Mesh Network Analysis of Proposals • Solution 1: • ERP bit definitions may be utilized by implementation. • HT protection refers to these bits. • Local use of ERP protection favors ERP mesh STA. In practice there would be very few NonERP devices and it would be more efficient to enable protection only around these STAs. • Solution 2: • No useful definitions for ERP bits. • Simple and local use of ERP protection. • Solution 3: • Meaningful ERP bits definitions as solution 1. • Robust against hidden NonERP STAs (note that this may not be required as hidden STA is different problem altogether). Ashish Shukla, Marvell Semiconductor

8. Example MP10 MP11 MP13 MP12 MP7 MP6 MP5 MP2 MP3 MP4 MP1 • Solution 1: • Use_Protection =1 in MP7. Use_Protection =1 in MP2/11 recommended. NonERP_Present =1 in MP7. • ERP protection enforced on MP2/7/11 • Solution 2: • Use_Protection and NonERP_Present reserved • ERP protection enforced on MP2/7/11 • Solution 3: • Use_Protection =1 in MP2/7/11. NonERP_Present =1 in MP7 • ERP protection enforced on MP1/2/3/6/7/11/12 • NOTE: This approach , due to NonERP bits ripple effect, may not be efficient (only MP5/4/11 do not have ERP protection) and degenerates more into a separate class of well known hidden STA problem. NonERP mesh STA NonERP (I)BSS ERP mesh STA Mesh Peer Link Neighbors within communication range Ashish Shukla, Marvell Semiconductor

9. It is not clear how to achieve ERP protection in 11s Mesh Network. The Use_Protection, NonERP_Present and Barker_Preamble_Mode bits definitions in the ERP IE should be extended in the Mesh STA context as described in this proposal. Inclusion of ERP IE into mesh beacon and Peer Link Management Action frame may help Mesh STA to implement ERP protection in Mesh Network. Conclusion Ashish Shukla, Marvell Semiconductor

10. Do you think that ERP protection in 11s mesh network is not clear? Yes No Abstain Do you think that 11s should define new rules to integrate ERP protection into 11s draft? Yes No Abstain Which solution do you vote for ? Solution 1 Solution 2 Solution 3 None Abstain Do you think that solutions described in this proposal address ERP protection problem and should be included in 11s draft? Yes No Abstain Straw Poll Ashish Shukla, Marvell Semiconductor

11. BACKUP Ashish Shukla, Marvell Semiconductor

12. ERP Protection in BSS ERP BSS3 Use_Protection =0 NonERP_Present= 0 ERP BSS2 Use_Protection =1 NonERP_Present= 0 NonERP BSS1 Use_Protection =1 NonERP_Present= 1 Ashish Shukla, Marvell Semiconductor