Discussion on Multiple Paging Groups IEEE Presentation Submission Template (Rev. 9) Document Number: IEEE S802.16m-09/1374 Date Submitted: Source: Baowei Ji, Zhouyue Pi, Ying LiVoice: Samsung Telecommunications America Hyunjeong Kang, Jungje Son Samsung Electronics Anshuman Nigam Samsung India Software Operation Venue: m AWD: IEEE m-09/0028r1, “Call for Comments and Contributions on Project m Amendment Content” Base Contribution: IEEE C802.16m-09/1374 AWD On Multiple Paging Groups Purpose: To be discussed and adopted by TGm for m amendment working document (AWD) Notice: This document does not represent the agreed views of the IEEE Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: and. Further information is located at and.

Conventional Paging Scheme Setup –One PG ID per BS: PA-1 = {BS1-100}; PA-2 = {BS } –One PG ID per MS Operation: –Each PA operates independently; MS does LU when crossing boundary of those PAs Pro: –Low paging broadcast because, e.g., BS does not page MS1 when it is in PA-1; –No extra paging delay because each PA could start paging immediately Con: –Potential ping-pang LU if an MS moves back-and-forth between the two PAs –Solution Attempt: Hierarchical Paging (see next slides) Slide 2

Hierarchical Paging (1/3) Slide 3

Hierarchical Paging (2/3) Slide 4 Setup –All the BSs belong to one Paging Area (PA) –Each MS monitors only one PG ID (i.e., hierarchical paging process is transparent to MSs) Operation: –Network pages an MS through first BS1-100, if no response, then BS ; this hierarchical paging process is transparent to MS. Ideally, network guesses where a specific MS could be within a PA at a given time; first page the MS in that place, if no response, then page it in a wider area; E.g., page an MS first in downtown San Francisco at day time, if no response, then page it in overall San Francisco city. Ideally, this paging process could be tailored for each MS in that PA. No scheme can beat this “ideal” scheme.

Hierarchical Paging in WiMAX Forum (3/3) Slide 5 Pro: –Transparent to MS. MS monitors one PG ID, no change to L2 spec –Low paging broadcast because, e.g., BS may not page MS1 Con: –Potential extra paging delay, e.g., MS2 is not paged in the first paging cycle; network may not have a good guess of the location of the MS within a PA. –Solution Attempt: Primary-Secondary Scheme (see next slides) Multiple PG IDs per MS (pri-PG_ID, sec-PG_ID) Multiple PG IDs per BS (pri-PA, sec-PA) Network completes paging the MS multiple times in multiple PAs in one paging cycle

Primary-Secondary Paging (1/4) Slide 6

Primary-Secondary Paging (2/4) Slide 7

Primary-Secondary Paging (3/4) Slide 8 Setup –BS1-100 belongs to pirmary PA (PG-pri), BS are of secondary PA (PG-sec) –MS is assigned PG-pri and PG-sec, i.e., it monitors multiple PG IDs –MS starts a timer when moves from pri-PA to sec-PA; stops the timer if it returns to pri- PA before the timer expires; but do LU if the timer expires. Operation: –If there is no LU, network pages the MS through first in the pri-PA (i.e., BS1-100), if no response, then in the sec-PA (I.e., BS ). Compared to conventional scheme of using two independent PAs (see Slide 1, i.e., pri-PA and sec-PA are two independent PAs) –Pro : no LU if the MS returns to the pri-PA before the timer expires, i.e., avoid ping-pang LU if the MS moves back-and-forth between the two PAs quickly –Con: All the BSs need to page the MS (e.g., MS2) if it moves from pri-PA into sec-PA and the timer is not expired yet.

Primary-Secondary Paging (4/4) Slide 9 Compared to Hierarchical Paging –Pro: similar low paging broadcast e.g., BS may not page MS1; –Con: Less flexibility because PA types (pri. or sec.) needed to be pre-defined and broadcast by a BS; Hard to specify a proper timer value: small value incurs more LU, while large value makes BS also page the MS if it is in sec-PA and the timer does not expires –Solution Attempt: avoid using the timer at all. Not scalable: What happens if there is multiple sec-PAs? What happens if there is no pri-PA? Similar extra paging delay if the paging offset of pri-PA is longer than that of sec-PA (see Slide 6) –Solution Attempt (see next slides): Avoid using pri-, sec- terms; MS monitors the paging messages of the shortest paging offset if the current BS carries multiple PG IDs that have been assigned to the MS.

Paging based on Paging Offset (1/3) Slide 10

Paging based on Paging Offset (2/3) Slide 11 MS1 (PG_1, PG3) MS2 (PG_2, PG3) MS3 (PG_3) MS4 (PG_1, PG_3)

Paging based on Paging Offset (3/3) Slide 12 Setup –BS1-100 = {PG-1, PG-3}; BS = {PG-2, PG-3}; BS = {PG-3} –PA_1 = {BS1-100}; PA_2 = {BS }; PA_3 = {BS } –MS may be assigned multiple PAs, then, it monitors multiple PG IDs Operation: –MS monitors the shortest paging offset if the current BS carries multiple PG IDs (e.g., MS1 monitors PG_1 when in PA_1). –Network pages MS4 through first in the PA_1 (i.e., BS1-100), if no response, then in PA_2 and PA_3 (i.e., BS ). –Network pages MS2 through first in the PA_2, if no response, then in PA_1 and PA_3 –Network pages MS3 in all three PAs. Compared to Primary-Secondary Scheme –Pro: no timer; no LU as long as the MS detects at least one PG ID from the current BS; similar low paging broadcast because e.g., BS may not page MS1; similar less paging delay because the 2 nd paging if necessary happens in the same paging cycle of the 1 st paging. –Con: PA_1 tries to page MS4 even it has been outside of PA_1 for a long time.

Conclusions Conventional Paging scheme may incurs ping-pang LU when neighbor PAs are small. Hierarchical Paging scheme may incurs extra paging delay of at least one paging cycle. Primary-Secondary Paging scheme is not scalable, and may incurs extra paging delay if paging offset s are not well defined. Paging-Offset Based Paging scheme handles ping-pang issue without extra paging delay. Slide 13