GroupID in VHT-SIG Field January 2010 doc.: IEEE 802.11-10/0073r0 May 2010 GroupID in VHT-SIG Field Date: 2010-05-17 Authors: Joonsuk Kim, Broadcom Corp. Joonsuk Kim

January 2010 doc.: IEEE 802.11-10/0073r0 May 2010 Background With resolvable LTFs for MU-MIMO transmission, we need a mechanism to identify which streams are for which user [1]. GroupID was proposed to identify users and space-time streams in MU-MIMO operation [1] PagingID mechanism also reaches the same goal if AP can collect the channel correlation information from STAs [2] We have reached a consensus to agree on having GroupID field in VHT-SIG A and keep working on the GroupID management (e.g., how to define and signal groups) Joonsuk Kim, Broadcom Corp. Joonsuk Kim

Location Indication for MU-Streams in VHT-SIG A January 2010 doc.: IEEE 802.11-10/0073r0 May 2010 Location Indication for MU-Streams in VHT-SIG A VHT-SIG A tells the number of columns of Qk (steering matrix for user k) in the order of assigned user number in the group. All STAs can listen to VHT-SIG A, so each participating user knows when to start to detect its own stream. VHT-SIG A includes following fields GroupID is used to indicate which group of STA(s) to receive MU-MIMO transmissions in the order of assigned user number Some of these bits may be reused for SU-MIMO packet Detail of GroupID management (e.g. How to assign & signal groups with GroupID) is TBD How to manage the GroupID field to support a large network of STAs is under investigation K is the max number of users to support with MU-MIMO y bits x bits Group ID # of columns of Qk (Nsts_k) for k=1,2,…,K Qk is the steering matrix for user k x>0, y >0 Nsts field x bits indicate the number of columns of Nsts for user 1,2,…, K. Details are TBD It is possible Nsts_k = 0 for certain k if STA k is not a recipient of MU-MIMO packet. Joonsuk Kim, Broadcom Corp. Broadcom Proprietary & Confidential. © 2009 Broadcom Corporation. All rights reserved. 3 Joonsuk Kim

January 2010 doc.: IEEE 802.11-10/0073r0 May 2010 Strawpoll Do you support adding a GroupID field (TBD bits) and an Nsts field (TBD bits) to VHT-SIGA of the 11ac preamble, and editing the spec framework document, 11-09-0992, accordingly? Yes: 57 No: 0 Abstain: 14 It passes Joonsuk Kim, Broadcom Corp. Broadcom Proprietary & Confidential. © 2009 Broadcom Corporation. All rights reserved. 4 Joonsuk Kim

Reference [1] “11-10-0073-02-00ac-GrpID-for-DL-MU-Transmission.ppt" January 2010 doc.: IEEE 802.11-10/0073r0 May 2010 Reference [1] “11-10-0073-02-00ac-GrpID-for-DL-MU-Transmission.ppt" [2] “11-10-0362-02-00ac-mu-mimo-sta-scheduling-strategy-and-related-phy-signaling.ppt” Joonsuk Kim, Broadcom Corp. Joonsuk Kim