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Partial AID. Authors:. Date: 2012-09-17. Authors:. Authors:. Motivation. In IEEE 802.11ac, what is the partial AID operation of the receiver? Access Point operation If the group ID field is equal to 0 and the partial AID field is equal to BSSID[39:47], AP decodes the following PSDU
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Partial AID Authors: Date: 2012-09-17 YonghoSeok, LG Electronics
Authors: Yongho Seok, LG Electronics
Motivation • In IEEE 802.11ac, what is the partial AID operation of the receiver? • Access Point operation • If the group ID field is equal to 0 and the partial AID field is equal to BSSID[39:47], AP decodes the following PSDU • Otherwise, it does not decode the following PSDU • STA operation • If the group ID field is equal to 63 and the partial AID field is equal to either (dec(AID[0:8]+dec(BSSID[44:47]XORBSSID[40:43])x2^5)mod 2^9 or 0, STA decodes the following PSDU • Otherwise, it does not decode the following PSDU Yongho Seok, LG Electronics
Motivation • In IEEE 802.11ah spec framework, SIG field of SU preamble does not have a group ID field • Then, in IEEE 802.11ah, what is the partial AID operation of the receiver? Can the receiver use the following rule? • Access Point operation • If the group ID field is equal to 0and the partial AID field is equal to BSSID[39:47], AP decodes the following PSDU • Otherwise, it does not decode the following PSDU • STA operation • If the group ID field is equal to 63 and the partial AID field is equal to either (dec(AID[0:8]+dec(BSSID[44:47]XORBSSID[40:43])x2^5)mod 2^9 or 0, STA decodes the following PSDU • Otherwise, it does not decode the following PSDU Yongho Seok, LG Electronics
Partial AID ambiguity issue • When BSSID[39:47] is equal to 0, STA decodes the following PSDU even though the corresponding PPDU is addressed to AP Issue Points Yongho Seok, LG Electronics
Partial AID ambiguity issue • When AP assign an AID to a STA that results in the PARTIAL_AID value, as computed using (dec(AID[0:8]+dec(BSSID[44:47]XORBSSID[40:43])x2^5)mod 2^9, being equal to BSSID [39:47], the STA decodes following PSDU even though the corresponding PPDU is addressed to AP Issue Points Yongho Seok, LG Electronics
Proposal • For resolving partial AID ambiguity issue • Option 1: Add partial AID type field (1bit) in SIG [1] • Drawback is wasting a scarce SIG resource • Option 2: Modify partial AID rule as the following • For solving the issue on slide 6, A STA that transmits a PPDU to an AP shall set the TXVECTOR parameter PARTIAL_AID to (dec(BSSID[39:47]) mod (2^9-1))+1 • For solving the issue on slide 7,AP should not assign an AID to a STA that results in the PARTIAL_AID value, as computed using (dec(AID[0:8]+dec(BSSID[44:47]XORBSSID[40:43])x2^5)mod 2^9, being equal to (dec(BSSID[39:47]) mod (2^9-1))+1 • Preference is an Option 2 Yongho Seok, LG Electronics
Discussion • Do we need to consider the following OBSS issue? • When AP assign an AID to a STA that results in the PARTIAL_AID value, as computed using (dec(AID[0:8]+dec(BSSID[44:47]XORBSSID[40:43])x2^5)mod 2^9, being equal to (dec(Overlapping BSSID[39:47]) mod (2^9-1))+1, the STA decodes following PSDU even though the corresponding PPDU is addressed to Overlapping AP • If needed, the proposed solution is as the following • AP should not assign an AID to a STA that results in the PARTIAL_AID value, as computed using (dec(AID[0:8]+dec(BSSID[44:47]XORBSSID[40:43])x2^5)mod 2^9, being equal to (dec(Overlapping BSSID[39:47]) mod (2^9-1))+1 • And, a STA can request to change its AID when it is overhearing an uplink frames transmitted from other BSS Yongho Seok, LG Electronics
Conclusion • In order to resolve the partial AID ambiguity issue, two options are proposed • Preference is to modify partial AID rule instead of adding partial AID type field in SIG • Some AIDs may not be assigned for a STA • In 802.11ac Draft 3.0, an AP should not assign an AID to a STA that results in the PARTIAL_AID value, as computed using (dec(AID[0:8]+dec(BSSID[44:47]XORBSSID[40:43])x2^5)mod 2^9, being equal to 0 • Those AID can be used for the multicast frame transmission in a short MAC header Yongho Seok, LG Electronics
Reference • https://mentor.ieee.org/802.11/dcn/12/11-12-0832-02-00ah-sig-fields-design-of-long-preamble.ppt Yongho Seok, LG Electronics
Straw Poll • Do you support to modify partial AID rule as the following? • A STA that transmits a PPDU to an AP shall set the TXVECTOR parameter PARTIAL_AID to (dec(BSSID[39:47]) mod (2^9-1))+1 • AP should not assign an AID to a STA that results in the PARTIAL_AID value, as computed using Equation (9-8a), being equal to either (dec(BSSID[39:47]) mod (2^9-1))+1 or (dec(Overlapping BSSID[39:47]) mod (2^9-1))+1 Yongho Seok, LG Electronics