1. doc.: IEEE 802.11-11/0645r5 SubmissionLiwen Chu Etc.Slide 1 Beamforming in IBSS, Mesh BSS, AP as Beamformee Date: 2011-05-11 Authors: Date: May 2011

2. doc.: IEEE 802.11-11/0645r5 Submission Date: May 2011 NDPA The RA of an NDPA may be either a unicast or the broadcast MAC address. The AID in each STA Info field contains the AID of the STA expected to process the following NDP frame and prepare the sounding feedback. Frame Control Duration TARA Sounding Sequence STA Info 1 …… STA Info n FCS AIDFeedback TypeNC. Index NDPA frame format

3. doc.: IEEE 802.11-11/0645r5 Submission Issues with AP, IBSS STA, Mesh STA as Beamformee When the receiver(s) of an NDPA includes an AP, what should be put in the AID field of the STA Info field for the AP? Do we allow broadcast NDPA with an AP as beamformee? When the receiver of an NDPA is a STA in a IBSS, there is no AID associated with it. Do we allow broadcast NDPA in a IBSS? When the receiver of an NDPA is a STA in a mesh BSS, there are multiple AIDs associated with it. Such AIDs can not be used in broadcast NDPA easily. Do we allow broadcast NDPA in a mesh BSS? Frame Control Duration TARA Sounding Sequence STA Info 1 FCS AIDFeedback TypeNC. Index Date: May 2011 STA1AP NDPA What AID should be put here? Mesh STA1 NDPA Mesh STA2

4. doc.: IEEE 802.11-11/0645r5 Submission AP as Beamformee Solutions Solution 1: Allow unicast NDPA with an AP as beamformee. –The AID field of an AP in STA Info field can be defined as one of the AID values that is never allocated to non-AP STAs. Such values include 0, i.e.12 zero bits, or any value from 2008 to 4095. Solution 2: Allow broadcast NDPA with an AP as beamformee. –The AID field of an AP in STA Info field can be defined as one of the AID values that is never allocated to non-AP STAs. Such values include 0, i.e.12 zero bits, or any value from 2008 to 4095. –If a non-AP STA is allowed to do DL MU-MIMO transmission, solution 2 clarifies that an AP can be the destination of DL MU-MIMO transmission. –If a non-AP isn’t allowed to do DL MU-MIMO transmission, a NDPA+NDP of a non-AP STA can get compressed beamforming reports from multiple STAs. This is a minor improvement. Propose to select Solution 1, because in the current 11ac draft, a non-AP STA cannot do DL MU-MIMO transmission. Date: May 2011

5. doc.: IEEE 802.11-11/0645r5 Submission IBSS Beamforming Solution Solution 1: allow unicast NDPA with IBSS STA as beamformee. –In a IBSS, the AID field in STA Info field can be defined as 12 LSBs of the STA’s MAC address, one of the AID values that is never allocated to non-AP STAs in a BSS. The RA of NDPA will be used to identify the beamformee. Solution 2: allow broadcast NDPA with IBSS STA as beamformee –In a IBSS, the AID field in STA Info field will include the 12 LSBs of the STA’s MAC address. A IBSS STA may have neighbor STAs with same 12 LSBs of their MAC addresses. In such a case, the NDPA with multiple STA info shall not include the STAs with same 12 LSBs of their MAC addresses. –However, GID distributed management is difficult to define. Propose to select solution 1. Date: May 2011

6. doc.: IEEE 802.11-11/0645r5 Submission Mesh BSS Beamforming Solutions Solution 1: allow unicast NDPA with mesh STA as beamformee. –The AID field in STA Info field can be defined as 12 LSBs of the STA’s MAC address, mesh AID, one of the AID values that is never allocated to non-AP STAs in a BSS. The RA of NDPA will be used to identify the beamformee. Solution 2: allow broadcast NDPA with mesh STA as beamformee. –The AID field in STA Info field can be defined as 12 LSBs of Mesh AID. If broadcast NDPA is received, AID and TA have to be used to identify the beamformee. –The AID field in STA Info field can be defined as 12 LSBs of the STA’s MAC address. A mesh STA may have neighbor STAs with same 12 LSBs of their MAC addresses. in such case, NDPA with multiple STA info shall not include the STAs with same 12 LSBs of their MAC addresses. –GID distributed management should be defined. Each STA broadcasts its GID allocation and its 1-hop neighbor’s GID allocations through beacon and action frames. A STA shall not use the GIDs that are already allocated by its 1-hop neighbors and 2-hop neighbors. Propose to select solution 1. Date: May 2011 Mesh STA1 Mesh STA3 Mesh STA2 Mesh STA4 STA3 AID=10 STA 4 AID=9 STA3 AID=7 STA 4 AID=10 Broadcast NDPA (AID10, AID 6) Mesh STA1 Mesh STA3 Mesh STA2 Mesh STA4 GID 6: STA3, STA7 MU-MIMO PPDU(GID 6) GID 6: STA4, STA5 A STA needs to decode more information if there is no GID negotiation. When, a mesh AID is used for AID info field, a STA needs to use AID and TA to decide if the broadcast NDPA is for it.

7. doc.: IEEE 802.11-11/0645r5 Submission Normative Text Allow unicast NDPA with AP as beamformee, allow unicast NDPA with IBSS STA as beamformee, allow unicast NDPA with mesh STA as beamformee. –One common AID value will be used for these three cases to simplify the protocol. Such value is one of the AID values that is never allocated to non-AP STAs in a BSS. The specific value is 0. Change the paragraph at P79L3 (D0.4) as follows: If(Ed) the NDPA frame includes more than one STA Info field, the RA of the NDPA frame shall be set to the broadcast address.(#958) If the NDPA frame includes a single STA Info field, the RA of the NDPA frame shall be set to the MAC address of the beamformee identified by the AID in the STA Info field.(#957) Insert the following at P79L7 (immediately after the preceding paragraph): A beamformer that sends an NDPA frame to a beamformee that is an AP, mesh STA or STA that is a member of an IBSS, shall include a single STA Info field in the NDPA frame and shall set the AID field in the STA Info field to 0. Date: May 2011