Transcript IEEE C802.16m-08/1011r1

Service Continuity of Enhanced-MBS
Document Number:
IEEE C802.16m-08/1011
Date Submitted:
2008-9-5
Source:
Chun-Yen Wang, Chun-Yuan Chiu, Fang-Ching (Frank) Ren,
Richard Li, Wern-Ho Sheen
ITRI
Information and Communications Research Laboratories,
195 Chung Hsing Rd., Sec.4 Chu Tung, Hsin Chu, Taiwan 310, R.O.C.
Voice:
E-mail: {ChunYen, ccy, frank_ren, richard929, whsheen}
@itri.org.tw
*<http://standards.ieee.org/faqs/affiliationFAQ.html>
Re : IEEE 802.16m-08/033 - Call for Contributions on Project 802.16m System Description Document (SDD), on the topic of “MAC
aspects of enhanced MBS”
Venue:
Kobe, JP
Base Contribution:
N/A
Purpose:
For discussion and approval by TGM
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Outline
• Scenario description
• Service continuity of E-MBS:
– Inter-EMBS Zone transition of a connected-state MS
– Inter-EMBS Zone transition of an idle-state MS
• From multi-BS transmission mode to
single-BS transmission mode
• From single-BS transmission mode to
single-BS (multi-BS) transmission mode
• From multi-BS transmission mode to
multi-BS transmission mode
1
Scenario Description (1)
• Assumptions:
– An E-MBS service area is the coverage of a set of BSs where some EMBS service(s) is announced and available to be received
– A BS within the service area is responsible to forward the associated EMBS data from gateway by using single-BS transmission mode or
multi-BS transmission mode
– Each BS capable of providing E-MBS service belongs to a certain EMBS Zone, identified by a unique MBS_Zone ID
– The same CID and same Security Association (SA) is used for
transmitting the content of certain E-MBS service(s) in a E-MBS Zone
– Different CIDs or different SAs may be used in different E-MBS Zones
for the same E-MBS service
2
Scenario Description (2)
– A BS is allowed to turn off the transmission of an E-MBS service if
there is no subscriber interesting for this service
– A MS can continue to receive E-MBS data within the service area
regardless of the MS operation mode (i.e., connected state/idle state)
E-MBS service area
Zone 4
Zone 1
Zone 2
single-BS transmission mode
Zone 4
multi-BS transmission mode
Zone 6
Zone 5
Zone 3
Zone 7
3
E-MBS Service Continuity of a Connected-State MS
•
Target BS decision:
– Serving BS criteria for recommendation of
target BS may include factors such as
expected MS performance at potential target
BS, BS and network loading conditions, MS
QoS requirements, and E-MBS service
availability.
•
E-MBS HO decision:
– An E-MBS service needs HO if the target BS
does not belong to the associated E-MBS Zone
•
MS
SBS
TBS
GW
Unicast HO REQ
HO preparation phase
HO pre-notification
E-MBS HO decision
HO procedure:
– …
…
Unicast HO RSP
Target BS decision
4
E-MBS Service Continuity of an Idle-State MS
• During idle state, a MS may have following methods to
achieve E-MBS service continuity
– Method 1:
perform location update procedure to update CIDs when the MS
detects a change in E-MBS Zone
– Method 2:
perform location update procedure when the MS detects a change in EMBS Zone, unless the MS already has the CID mappings through a
CID pre-allocation scheme [1]
– Method 3:
transit to connected state by network reentry procedure when the MS
awakes to a possible inter-MBS Zone transition
5
Method 1
perform location update procedure to update CIDs
when the MS detects a change in E-MBS Zone…
• If the MS reselects a preferred BS
during MS paging unavailable
interval, and then
• detects the change of E-MBS Zone
by monitoring the MBS zone
identifier list which is transmitted by
the new preferred BS in the downlink
broadcast message,
• it can update its CIDs and resume
content reception through locationupdate procedure
Original
preferred BS
MS
New
preferred BS
GW
Reselects a preferred BS during
MS paging unavailable interval
E-MBS HO decision
Location-update
procedure for
CID updating
E-MBS service
resumption
6
Method 2
perform location update procedure when the MS detects a change in
E-MBS Zone, unless the MS already has the CID mappings through
a CID pre-allocation scheme[1]…
• The CID pre-allocation scheme
informs MSs within a certain E-MBS
Zone regarding the mapping of CIDs
used in the current E-MBS Zone to
new CID within a neighboring EMBS zone
• When a MS moves to a new zones, it
can immediately (and internally)
update its CIDs and resume content
reception without the need to perform
CID update through location-update
Original
preferred BS
MS
New
preferred BS
GW
Reselects a preferred BS during
MS paging unavailable interval
E-MBS HO decision
Location-update procedure
for E-MBS service resumption
7
Method 3
transit to connected state by network reentry procedure
when the MS awakes to a possible inter-MBS Zone transition…
• When the MS awakes to a possible
inter-MBS Zone transition by some
measurements,
• it transits to connected state by
network reentry procedure
MS
preferred BS
(SBS)
TBS
GW
some measurements
trigger network
reentry procedure
E-MBS service continuity procedure
of a connected-state MS
8
From Multi-BS Transmission Mode to
single-BS Transmission Mode
•
•
•
For a E-MBS service using multi-BS transmission mode, gateway is responsible to
schedule resource and decides a MCID for the service
Since this resource can not be reused in a guard range due to co-channel
interference, the scheduling information should be forwarded to all BSs within the
guard range
gateway
…
multi-BS Tx mode
Guard range
single-BS TX mode
9
From single-BS Transmission Mode to
single-BS (Multi-BS) Transmission Mode
• For a E-MBS service using single-BS transmission mode, BS is responsible
to schedule resource and decides a CID for the service
• Therefore, its neighboring BSs are not aware of the CID used by itself for
the service unless the CID pre-allocation scheme proposed in [1] is used
• In order to avoid the overhead of the CID pre-allocation, we prefer to adopt
the method 3 to achieve E-MBS service continuity for this scenario
• Moreover, the handover procedure for a Connected-State MS in method 3
is more able to avoid packet loss by data forwarding
• In idle mode, a MS may reselect a preferred BS during MS paging
unavailable interval according to some measurements.
• A stricter threshold of these measurements can be used for triggering
network reentry procedure in the method 3
10
From Multi-BS Transmission Mode to
Multi-BS Transmission Mode
• It seems like there is no reason to use different resource and MCIDs in two
neighboring E-MBS Zones for the same E-MBS service, instead of
combining them to a bigger E-MBS Zone
• If there is some rare reasons resulting in this situation, we think the two
neighboring E-MBS Zones should be able to adopt same MCID allocated
by gateway
• If there is some rare reasons resulting in different resource and MCIDs
used in two neighboring E-MBS Zones for the same E-MBS service, we
prefer to adopt the method 1 to handle these rare cases
11
Proposed Text for SDD
• 15.1: General Concepts
Add the assumptions described in page 2-3
• 15.x: Service Continuity of Enhanced-MBS
15.x.1: E-MBS Service Continuity of a Connected-State
MS
Add the discussion described in page 4
15.x.2: E-MBS Service Continuity of an Idle-State MS
Add the discussion described in page 5-8
12
Reference
1.
IEEE C802.16maint-08/171r9, “Improvement in MBS in
802.16REV2 ”
13