Discussion on Multiple Paging GroupsIEEE 802.16 Presentation Submission Template (Rev. 9) Document Number: IEEE S802.16m-09/1374Date Submitted: 2009-07-06

Source:Baowei Ji , Zhouyue Pi, Ying Li Voice: +1-972-761-7167Samsung Telecommunications America E-mail: bji@sta.samsung.com

Hyunjeong Kang, Jungje SonSamsung Electronics

Anshuman Nigam Samsung India Software Operation

Venue:802.16m AWD: IEEE 802.16m-09/0028r1, “Call for Comments and Contributions on Project 802.16m Amendment Content”

Base Contribution: IEEE C802.16m-09/1374 AWD-15.2.17 On Multiple Paging Groups

Purpose:To be discussed and adopted by TGm for 802.16m amendment working document (AWD)

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Conventional Paging Scheme

• Setup– One PG ID per BS: PA-1 = {BS1-100}; PA-2 = {BS101-500}

– 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., BS101-500 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 BS101-500; 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., BS101-500 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), BS101-500 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., BS101-500).

• 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., BS101-500 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 BS101-500 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}; BS101-200 = {PG-2, PG-3}; BS201-500 = {PG-3}

– PA_1 = {BS1-100}; PA_2 = {BS101-200}; PA_3 = {BS201-500}

– 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., BS101-500).

– 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., BS101-500 may not page MS1; similar less paging delay because the 2nd paging if necessary happens in the same paging cycle of the 1st 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