TIM and Page Segmentation Month Year doc.: IEEE 802.11-yy/xxxxr0 September 2012 TIM and Page Segmentation Date: 2012-09-17 Authors: Name Affiliations Address Phone Email Chittabrata Ghosh Nokia 2054 Unversity Ave., # 600, Berkeley, CA- 94704 +1 650 200 7566 chittabrata.ghosh@nokia.co m Sayantan Choudhury Klaus Doppler Esa Tuomaala Eric Wong Broadcom Sunnyvale, CA +1 408 922 6672 ewong@broadcom.com Matthew Fischer mfischer@broadcom.com Minyoung Park Intel Hillsboro, OR +1 503 712 4705 minyoung.park@intel.com Adrian Stephens Tom Tetzlaff Emily Qi Simone Merlin Qualcomm San Diego, CA +1 858 845 1243 smerlin@qualcomm.com Santosh Abraham Menzo Wentink Alfred Asterjadhi Amin Jafarian Hemanth Sampath VK jones Chittabrata Ghosh, Nokia John Doe, Some Company

Authors: September 2012 Month Year doc.: IEEE 802.11-yy/xxxxr0 Name Affiliations Address Phone Email Yong Liu Marvell Hongyuan Zhang Sudhir Srinivasa George Calcev Huawei Rolling Meadows, IL, USA George.Calcev@huawei.com Osama Aboul Magd Young Hoon Betty Zhao David Yangxun Bin Zhen ChaoChun Wang MediaTek James Wang Jianhan Liu Vish Ponnampalam James Yee Huai-Rong Shao   Samsung Electronics Chiu Ngo Minho Cheong ETRI Jae Seung Lee Hyoungjin Kwon Heejung Yu Sok-kyu Lee Sun, Bo         ZTE Lv, Kaiying         Chittabrata Ghosh, Nokia John Doe, Some Company

Authors: September 2012 Month Year doc.: IEEE 802.11-yy/xxxxr0 Name Affiliations Address Phone Email Yongho Seok LG Electronics yongho.seok@lge.com Jinsoo Choi Jeongki Kim Jin Sam Kwak Ken Mori Panasonic Rojan Chitrakar Haiguang Wang I2R Shoukang Zheng Yeow Wai Leong Zander Lei Jaya Shankar Anh Tuan Hoang Joseph Teo Chee Ming Chittabrata Ghosh, Nokia John Doe, Some Company

September 2012 Introduction Based on the AID hierarchical addressing [1], a Page consists of multiple blocks (e.g., 32) A page segment may refer to an ordered range of blocks (e.g., 8) out of all blocks in one Page TIM segmentation is accepted in 802.11ah specification framework supporting a subset of STAs per TIM segment Need a mechanism for assignment of page segments among multiple TIM segments Indication of such assignment to STAs in allocated page segments Chittabrata Ghosh, Nokia

September 2012 Motivation STAs waking up in DTIM for group addressed frames are assigned in subsequent TIM segments for unicast (DL/UL) traffic Challenge – Indication of subset of STAs assigned to each TIM segment Within assigned page segment in a TIM segment, intermediate blocks may not have buffered data at AP STAs with no UL data in such blocks need to still wake up at assigned TIM segment We propose to introduce a Segment Count IE in DTIM beacon frame to indicate length of page segment assigned to TIM segments We propose a mechanism for early indication of buffered data per block Chittabrata Ghosh, Nokia

Page Segmentation Ordered Blocks in Page 1 TIM Segment 1 TIM Segment 2 September 2012 Page Segmentation We propose to have a fixed length page segment per TIM segment within one DTIM beacon interval Length of page segment may vary over multiple DTIM beacon intervals Length of page segment = (Number of blocks in one page / number of TIM segments in DTIM beacon interval) Each ordered page segment is assigned sequentially to TIM segments, first page segment being assigned to DTIM segment Ordered Blocks in Page 1 TIM Segment 1 (DTIM) TIM Segment 2 TIM Segment N Page Segment 1 Page Segment 2 Page Segment N Chittabrata Ghosh, Nokia

Page Bitmap for Power Save September 2012 Page Bitmap for Power Save Block level indication of buffered traffic in DTIM beacon frame STAs with its corresponding block bit set to 0 go back to sleep after decoding DTIM beacon frame and may not wake up at assigned TIM segment Page Bitmap field for buffered traffic indication of blocks in assigned page segments for all TIM segments in DTIM beacon interval This field may be indicated in Segment Count IE The first block in Page Bitmap corresponds to Page offset in segment count IE The terminal block in Page Bitmap corresponds to end block in last assigned page segment Size of Page Bitmap varies between 0 – 4 octets (assuming a maximum of 32 blocks in one Page) Chittabrata Ghosh, Nokia

Frame Format for Segment Count IE September 2012 Frame Format for Segment Count IE The segment count IE (4-8 octets) shall consist of the following fields: Element ID (1 octet): Identification of the segment count IE Length (1 octet): Length of this IE Page Index (2 bits): Indication of page currently assigned in beacon Page Segment Count (5 bits) field indicating number of TIM segments; for instance, A value of 4 indicates 4 TIM segments in DTIM beacon interval A value of 8 indicates 8 TIM segments in DTIM beacon Page Offset (5 bits) field indicating the first block in assigned page segments Reserved (4 bits): Reserved bits for future use Page Bitmap (0- 4 octets) field for blocks of all page segments in DTIM element Element ID Length Page Index Page Segment Count Page Bitmap Page Offset Reserved Chittabrata Ghosh, Nokia

Segment Count IE in Beacon September 2012 Segment Count IE in Beacon Segment count IE is only transmitted in DTIM beacon frames and not in TIM segments This element indicates assignment of STAs in TIM segments Indicates wake-up interval for STAs within page segments STAs within the assigned page segment wake up at corresponding TIM segment sequentially based on the page segment count field in the IE Length of page segment = (Number of blocks in Page Bitmap /page segment count) Page offset and Page segment count fields in the segment count IE indicate initial block offset and range of TIM element in each TIM segment Block offset / start = page offset + ((length of page segment) * (TIM segment number -1)) + 1 Block Range = page offset + length of page segment * TIM segment number STAs with their block bit set to 0 in Page Bitmap field may not wake up at assigned TIM segment Chittabrata Ghosh, Nokia

Partial Virtual Bitmap September 2012 TIM IE In IEEE Spec Framework: When the complete traffic indication bitmap is divided into multiple segments, each segment shall indicate the range of the AIDs (bitmap) it is covering Proposal: include the TIM Segment Number field in TIM IE TIM Segment Number field (5 bits): indicates the index of the TIM Segment The TIM bitmap information covered in the TIM IE is calculated as follows: TIM segment start = page offset + ((length of page segment) * (TIM segment number -1)) + 1 TIM segment end = page offset + length of page segment * TIM segment number Partial Virtual Bitmap (TIM Segment bitmap) TIM Segment Number (n) Page Index R 1 bit 5 bit 2 bit Bitmap control (1 octet) Element ID 1 octet Length DTIM Period DTIM Count Chittabrata Ghosh, Nokia

TIM Segmentation Illustration September 2012 TIM Segmentation Illustration Segment Count IE indicates assignment of page segments in following TIM segments Page (2048 STAs) in 1 DTIM Interval Beacon Page Segment 1 (512 STAs) Page Segment 2 (512 STAs) Page Segment 3 (512 STAs) Page Segment 4 (512 STAs) Page Segment Count = 4 Length of Page Segment Page Offset Short Beacon TIM Segment Number = 2 Short Beacon TIM Segment Number = 3 Short Beacon TIM Segment Number = 4 Segment Count IE for STAs in all Page Segments Page Segment 4 Page Segment 2 Page Segment 3 Page Segment 1 Chittabrata Ghosh, Nokia

September 2012 Summary We proposed to introduce a segment count IE in DTIM beacon frame in order to indicate length of page segments assigned to TIM segments We proposed to have a Page Bitmap field in segment count IE for early indication of buffered data for blocks in assigned page segments We proposed to add the TIM Segment Number field in TIM IE Chittabrata Ghosh, Nokia

Reference [1] TGah Efficient TIM Encoding, doc. IEEE 802.11-12/388r0 September 2012 Reference [1] TGah Efficient TIM Encoding, doc. IEEE 802.11-12/388r0 Chittabrata Ghosh, Nokia

September 2012 Straw Poll 1 Do you agree to have a fixed length page segment per TIM segment as described in Slide 4? Chittabrata Ghosh, Nokia

September 2012 Straw Poll 2 Do you agree to introduce a Page Bitmap field for early indication of block-level buffered data? Chittabrata Ghosh, Nokia

September 2012 Straw Poll 3 Do you agree to have a Segment Count IE as in Slide 7 for indication of assignment of STAs in TIM segments? Chittabrata Ghosh, Nokia

September 2012 Straw Poll 4 Do you agree to have the frame format for the Segment Count IE as shown in Slide 6? Chittabrata Ghosh, Nokia

September 2012 Straw Poll 5 Do you agree to include the TIM Segment Number field in the TIM IE as shown in Slide 8? Chittabrata Ghosh, Nokia