1. doc.: IEEE 802.11-12/117r0 Submission January 2012 Minyoung Park, Intel Corp.Slide 1 TGah TIM Operation Date: 2012-01-16 Authors:

2. doc.: IEEE 802.11-12/117r0 Submission January 2012 Minyoung Park, Intel Corp.Slide 2 Authors:

3. doc.: IEEE 802.11-12/117r0 Submission Introduction 11ah use case includes a large outdoor network [1] –For an outdoor smart grid network, the number of STAs can be 6000+ Transmitting the entire bitmap information in a Beacon frame has following issues –TIM element size may be as big as 6000+ /8 = 750+ bytes –Cannot serve a large number of STAs within one beacon interval For a very large network, the traffic indication bitmap may need to be divided into multiple segments and transmitted in multiple TIM elements Slide 3 January 2012 Minyoung Park, Intel Corp.

4. doc.: IEEE 802.11-12/117r0 Submission TIM Operation in the current 802.11 STD 802.11 STD: a TIM element has the information of the entire traffic indication bitmap for AID= [0:2007] –Only the AIDs set to 1 have data buffered at the AP –The AIDs =0 indicates that there is no data buffered at the AP –The AIDs not included in the TIM element indicate that the AP do not have any data buffered for the STAs with those AIDs AID:0 2007 Non-zero value Only the partial bitmap information is included in the TIM element Traffic indication bitmap Total bitmap January 2012 Minyoung Park, Intel Corp.Slide 4

5. doc.: IEEE 802.11-12/117r0 Submission TIM Operation for a Large Network A large outdoor network support in 11ah –Support 6000+ STAs One TIM element covering the entire traffic information may not be feasible due to a large bitmap size One beacon interval can support only limited number of STAs The traffic indication bitmap needs to be transmitted in multiple partial traffic indication bitmaps over multiple beacon intervals –The number of bitmap segments may be static or dynamic throughout the operation of the network Static: the size of each bitmap segment is fixed –STAs know the range of the received bitmap implicitly Dynamic: the size of each bitmap segment varies –STAs do not know the range of the received bitmap January 2012 Minyoung Park, Intel Corp.Slide 5

6. doc.: IEEE 802.11-12/117r0 Submission TIM Operation for a Large Network AID:0 Max AID (>2007) Non-zero value Traffic indication bitmap Total traffic indication bitmap Range of bitmap segment 1Range of bitmap segment 2Range of bitmap segment N … LL+1 TIM-1 (bitmap segment1)TIM-2(bitmap segment2)TIM-3(bitmap segment3) TIM-N (bitmap segment N) … TIM-1 M A partial virtual bitmap of segment 1 January 2012 Minyoung Park, Intel Corp.Slide 6 Multiple TIM elements covering a large AID bitmap –Example (other segmentations/mappings are also possible): Each bitmap segment needs to indicate the range of the bitmap segment it is covering –Required for a STA to know whether the AID of the STA is covered in the received TIM or need to look for the AID in the following TIMs

7. doc.: IEEE 802.11-12/117r0 Submission Conclusions For a large network in 11ah, the traffic indication bitmap may need to be segmented into one or more segments and transmitted in one or more TIM elements Each bitmap segment needs to indicate the range of the AIDs (bitmap) it is covering January 2012 Minyoung Park, Intel Corp.Slide 7

8. doc.: IEEE 802.11-12/117r0 Submission References [1] Rolf de Vegt, “Potential Compromise for 802.11ah Use Case Document,” 11-11/457r0. January 2012 Minyoung Park, Intel Corp.Slide 8

9. doc.: IEEE 802.11-12/117r0 Submission Straw Poll 1 Do you support the concept of dividing the complete traffic indication bitmap into one or more segments and transmitting in one or more TIM elements for a large network? –Y: –N: –A: Intel Corp. Slide 9Minyoung Park, Intel Corp.

10. doc.: IEEE 802.11-12/117r0 Submission Straw Poll 2 Do you support that when the complete traffic indication bitmap is divided into multiple segments, each segment shall indicate the range of the AIDs (bitmap) it is covering? –Y: –N: –A: Intel Corp. Slide 10Minyoung Park, Intel Corp.