Mobility Consideration for E-MBS

Document Number:IEEE C802.16m-08/584r1

Date Submitted:2008-7-15

Source:Chun-Yen Wang, Chun-Yuan, Chiu, Fang-Ching (Frank) Ren, Richard Li, Wern-Ho Sheen Voice:ITRI, NCTU/ITRI E-mail: {ChunYen, ccy, frank_ren, richard929, whsheen}Information and Communications Research Laboratories, @itri.org.tw195 Chung Hsing Rd., Sec.4 Chu Tung, Hsin Chu, Taiwan 310, R.O.C.

*<http://standards.ieee.org/faqs/affiliationFAQ.html> Re : IEEE 802.16m-08/024 - Call for Contributions on Project 802.16m System Description Document (SDD), on the topic of “Upper MAC concepts and methods (limited to addressing, mobility and power management)” Venue:

Denver, USBase Contribution:

N/APurpose:

For discussion and approval by TGM

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Introduction

• This contribution discusses and proposes some aspects of mobility consideration for E-MBS, including, – Service continuity – Intra(Inter)-MBSFN mobility – Dedicated carrier consideration

Service Continuity

• In 802.16m, MS may continue to receive MBS transmissions from BS during Connected State and Idle State

• During Connected State, MS may perform handover procedure to achieve service continuity

• During Idle State, MS may have two methods to achieve service continuity– Transit to Connected State at source BS and then perform handover

procedure– Perform cell selection procedure and retrieve the MBS service from

target BS

Comparison

MS transits to Connected State at source BS and then performs handover procedure

MS performs cell selection procedure and retrieves the MBS service from target BS

Service interruption time

Low, may be limited to the maximum handover interruption time specified in the TGm SRD

High, may be more than the MBS channel change interruption times

Control signal

overhead High, control signal for transiting from Idle State to Connected State + handover

Relative low

Packet loss Minor May be major

• IEEE 802.16m shall support E-MBS in an efficient manner, including multi-cell multicast-broadcast single frequency networks (MBSFN)

• In MBSFN, MBS service is coordinated and synchronized among a group of BS to allow macro-diversity

• The mobility between those BS (intra-MBSFN mobility) does not require to trigger the service continuity procedure,

• but may require to trigger location update procedure and handover procedure for unicast service

Intra(Inter)-MBSFN Mobility (1/2)

paging group 1

paging group 2

paging group 3

MBSFN

Intra(Inter)-MBSFN Mobility (2/2)

• MS may initiate the location update procedure by monitoring the paging group ID

• MS may initiate the handover procedure for unicast services by monitoring the received signal strength indication

• MS may perform some procedure to achieve service continuity for a specific MBS service if it detects the occurrence of inter-MBSFN mobility by monitoring the signal strength of the received MBS service

MBSFNfor service 1

MBSFNfor service 3

MBSFNfor service 2

Service continuity procedure is required only for service 2

Dedicated Carrier Consideration

• The TGm SRD (IEEE 802.16m-07/002r4) specifies that IEEE 802.16m shall support E-MBS delivery via a dedicated carrier

• BS shall be able to page a MS at dedicated carriers (i.e., a MS does not periodically return to mixed carrier during paging listening interval)

• Handover management and location management at dedicated carrier are FFS

Proposed Text for SDD

• Section 15.1: General Concepts – In 802.16m, MS may continue to receive MBS transmissions from BS

during Connected State and Idle State• Section 15.x: Mobility Consideration for E-MBS

– During Connected State, MS may perform handover procedure to achieve service continuity

– During Idle State, MS may have two methods to achieve service continuity• Transit to Connected State at source BS and then perform handover

procedure• Perform cell selection procedure and retrieve the MBS service from target

BS– MS may initiate one of above procedures to achieve service continuity

for a specific MBS service by monitoring the signal strength of the received MBS service