IEEE C802.16n-11/0176
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Multicast over Power Saving Mode Operation
Date
Submitted
2011-09-12
Source(s)
Eunkyung Kim, Sungcheol Chang,
Sungkyung Kim, Won-Ik Kim,
Miyoung Yun, Hyun Lee, Chulsik Yoon,
Kwangjae Lim
E-mail:
ekkim@etri.re.kr
scchang@etri.re.kr
ETRI
Re:
“IEEE 802.16n-11/0013r1,” in response to Call for Comments on 802.16n (GRIDMAN) AWD
Abstract
Multicast operation during power saving mode (i.e., sleep and idle mode) in 802.16n
Purpose
To discuss and adopt the proposed text in the AWD of 802.16n
Notice
Release
Patent
Policy
This document does not represent the agreed views of the IEEE 802.16 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.
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 802.16.
The contributor is familiar with the IEEE-SA Patent Policy and Procedures:
<http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and
<http://standards.ieee.org/guides/opman/sect6.html#6.3>.
Further information is located at <http://standards.ieee.org/board/pat/pat-material.html> and
<http://standards.ieee.org/board/pat>.
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Multicast over Power Saving Mode Operation
Eunkyung Kim, Sungcheol Chang, Won-Ik Kim, Seokki Kim, Sungkyung Kim, Miyoung Yun, Hyun
Lee, Chulsik Yoon, Kwangjae Lim
ETRI
Introductions
IEEE 802.16n AWD [4] describes optimized MAC protocol for unicast and multicast transmission based on the
802.16n SRD [1]. According to the multicast operation, an HR-MS regardless of what mode the HR-MS is
currently in can receive multicast service from HR-BS. To ensure proper multicast operation in power saving
operation (i.e., sleep or idle mode), this contribution provides multicast operation on power saving operation.
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Idle mode operation
According to general operation of idle mode operation, paging cycle is defined per each MS not as a group of
MSs. However, an HR-BS or paging server may not know the multicast group of the subordinate MSs
(especially in idle mode). To support idle mode as shown Figure 1, the HR-BS has to indicate whether the
multicast data is transmitted or not at each paging listening interval of all subordinate HR-MSs, which may
make an overhead of message (i.e., PAG-ADV message).
MS1
(MGID#02)
MS2
(MGID#01)
MS3
(MGID#01)
MS4
(MGID#02)
Paging listening interval
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MGID#01 (talk burst)
Paging unavailable interval
MGID#02 (talk burst)
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Figure 1 – Indication of multicast transmission in idle mode operation (each PAG-ADV message has
to indicate whether multicast is transmitting or not in advance)
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Sleep mode operation
Similar to idle mode operation, sleep cycle is defined per each MS not a group of multicast. Thus, TRF-IND
message has to include the indication of multicast transmission or sleep cycle should be adjusted based on the
multicast group. However, HR-BS may not know the multicast group of the subordinate MSs. To support sleep
mode as shown Figure 2, the HR-BS has to indicate whether the multicast data is transmitted or not at each
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listening window of all subordinate HR-MSs, which may make an overhead of message (i.e., TRF-IND
message).
MS1
(MGID#02)
MS2
(MGID#01)
MS3
(MGID#01)
MS4
(MGID#02)
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Listening window
MGID#01 (talk burst)
Sleep window
MGID#02 (talk burst)
Figure 2 – Indication of multicast transmission in sleep mode operation (each TRF-IND message may
indicate whether multicast is transmitted or not in advance)
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Power saving operation for multicast
To support power saving (i.e., sleep and idle mode) and alleviate the message overhead of TRF-IND/PAG-ADV,
multicast specific cycle is proposed, which consists multicast available interval and multicast unavailable
interval (see Figure 3).
Multicast
indication cycle
MS1
(MGID#02)
MS2
(MGID#01)
MS3
(MGID#01)
MS4
(MGID#02)
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Paging listening interval / listening window
MGID#01 (talk burst)
Paging unavailable interval / sleep window
MGID#02 (talk burst)
Multicast available interval
Multicast unavailable interval
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Figure 3 – multicast indication cycle to indicate whether multicast is transmitting or not in advance
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In multicast available interval, an indication is transmitting to indicate whether multicast is transmitting in
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advance. The indication consists of “multicast group indication (MG-IND) message” and “multicast
transmission indication (MT-IND) message.” MG-IND message is transmitted at the beginning of multicast
available interval to indicate whether a multicast is served by an indicating multicast group using MGIND
bitmap (see Figure 4). As shown the Figure 4, all possible multicast groups are divided into subgroups:
# of multicast groups in a subgroup = (# of all possible multicast groups) / (length of MGID bitmap),
(1)
where # of all possible multicast groups is 212 and length of MGID bitmap is assumed to be M. Thus, # of
multicast groups in a subgroup is 212/M. In the example of Figure 4, # of multicast groups in a subgroup is 27.
MGIND bitmap(32bits)
0
1
1
1
0
0
0
0x080~0x0AF
0x040~0x07F
0x000~0x03F
1
0
1
0xF40~0xF7F
0x0B0~0x0FF
0xF00~0xF3F
0x100~0x13F
0xF80~0xFAF
0xEB0~0xEFF
0xFB0~0xFFF
Multicast Group ID
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Figure 5 shows how to transmit MG-IND, MT-IND, and Data for multicast group. As shown the Figure 5, MGIND indicates MT-IND message and MT-IND indicates the location of data of corresponding multicast group.
MG-IND
MSG
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MT-IND
MSG
MT-IND
MSG
Data for
MGID(0x06F)
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Data for
MGID(0xFA0)
Figure 4 – MGIND bitmap (multicast group is divided into subgroups whose number is the same as
the length of MGIND bitmap), where length of MGID bitmap is 32 and range of multicast group is
0~232-1.
Data for
MGID(0x041)
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Figure 5 – transmission of Indication (i.e., MG-IND, MT-IND messages) and multicast data
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MG-IND and MT-IND messages
An HR-BS providing multicast service transmits AAI-MG-IND message (see Table 1) in the beginning of
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available interval in multicast indication cycle. This message indicates whether there is DL multicast traffic for a
specific multicast group. There are two formats for the AAI-MG-IND message, indicated by the indication type
field. If the indication type is set to “0,” this message indicates the multicast traffic transmission offset directly.
Otherwise, MGIND bitmap indicates a subgroup of multicast group and further information will be transmitted
by AAI-MT-IND (see Table 2). AAI-MT-IND message shall be transmitted at the offset indicated by AAI-MGIND message. Based on the action code in AAI-MT-IND message, HR-MSs may receive multicast traffic or
perform network entry or exit sleep mode.
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Table 1 – MG-IND message field description
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Field
Indication type
Size (bits)
1
Value/Description
0b0: full MGID indication
0b1: MGIND+MTIND indication
Condition
If (Indication type == 0b0) {
For(i=0; i<Num_MGID;i++){
Num_MGID is the number of multicast group to indicate
multicast traffic is transmitting.
Range : 0 ~ 32
Multicast Group ID
12
Offset of multicast traffic
4
frame number offset in which the ABS transmits multicast
traffic
Shall be present
}
}Else if(Indication type == 0b1) {
MGIND bitmap
M(=64)
Indicates whether a corresponding subgroup of multicast
group has multicast data to transmit, where the N-th bit of
MGIND bitmap [MSB corresponds to N = 0] corresponds to
MGIDs in a subgroup (212×N/M to 212× (N+1)/M-1)
0: There is no multicast traffic for any of multicast groups in
the corresponding multicast subgroup
1: There is multicast traffic for at least one multicast group in
the corresponding multicast subgroup
For (i=0; i<L; i++) {
Offset of multicast MT-IND message
2
frame number offset in which the ABS transmits MT-IND
message
0b00: first frame of this superframe
0b01: second frame of this superframe
0b10: third frame of this superframe
0b11: fourth frame of this superframe
L equals the number
of bits in MGIND
bitmap whose bit is
set to 1.
Shall be present
}
}
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Table 2 – MT-IND message field description
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Field
Size (bits)
Value/Description
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Condition
IEEE C802.16n-11/0176
Field
For (i=0; i<L; i++) {
MTIND bitmap
Size (bits)
K(=64)
Value/Description
Indicates whether a corresponding multicast group has
multicast data to transmit, where the Q-th bit of MTIND
bitmap [MSB corresponds to Q = 0] corresponds to MGID in
the subgroup ( Q is the value of logK LSB of multicast group
and MSB logM of multicast group is defined by MG-IND
message).
Condition
L equals the number
of bits in MGIND
bitmap whose bit is
set to 1 and whose
offset is the current
frame. The bits are
ordered by the
shortest MSB of
MGIND bitmap.
Shall be present
0: There is no multicast traffic for the corresponding multicast
group
1: There is multicast traffic for the corresponding multicast
group
For(j=0;j<P; j++){
P equals the number
of bits in MTIND
bitmap whose bit is
set to 1.
Action code
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If bit0 = 1, perform network entry or exit sleep mode
If bit1 = 1, perform ranging procedure with ranging purpose
indication is set to HR multicast service flow update(=0b1110)
If bit2 = 1, receiving multicast traffic
If (action code bit2 == 1){
Offset of multicast traffic
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frame number offset in which the ABS transmits multicast
traffic
Shall be present
}
}
}
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Messages related to multicast indication cycle
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References
To receive paging or requesting to set up the multicast connection, an HR-MS has to know the multicast
indication cycle which is transmitted by AAI-SCD.
In response to the requesting, DSA messages are exchanged between HR-BS and HR-MS and the DSA message
may include the multicast indication cycle to operate the proposed multicast operation.
In addition, multicast indication cycle is unique to multicast group zone and it may be update when an HR-MS,
receiving multicast service, is crossing across the multicast group zone as a part of HO/location update or when
the multicast indication cycle needs to update. To indicate whether the multicast indication cycle of neighbor
multicast group zone, multicast indication cycle may be included in NBR-ADV message.
Thus, RNG-RSP, NBR-ADV, AAI-SCD, and DSx messages have to include the multicast indication cycle.
[1] IEEE 802.16n-10/0048r1, “802.16n System Requirements Document including SARM annex,” March 2011.
[2] IEEE Std. 802.16TM-2009, “IEEE Standard for Local and metropolitan area networks; Part 16: Air Interface
for Broadband Wireless Access Systems,” May 2009.
[3] IEEE 802.16mTM-2011, IEEE Standard for Local and metropolitan area networks; Part 16: Air Interface for
Broadband Wireless Access Systems; Amendment 3: Advanced Air Interface,” May 2011.
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[4] IEEE 802.16n-11/0015, “802.16n Amendment Working Draft,” August 2011.
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Proposed Text for the 802.16n Amendment Working Document (AWD)
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The text in BLACK color: the existing text in the 802.16n Amendment Draft Standard
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The text in RED color: the removal of existing 802.16n Amendment Draft Standard Text
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The text in BLUE color: the new text added to the 802.16n Amendment Draft Standard Text
Note:
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[-------------------------------------------------Start of Text Proposal---------------------------------------------------]
[Remedy1: Add the following text into Section 6.2.3 in the 802.16n AWD.]
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16.2.3 MAC Control messages
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[Insert the following row at the end of Table 683:]
16
xx
Multicast
AAI-MG-IND
xx+1
Multicast
AAI-MT-IND
Multicast Group
Indication
Message
Multicast Traffic
Indication
Message
Broadcast
Broadcast or
Multicast
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[Remedy2: Add the following row into the Table 685, Section 16.2.3.2, page 23-24 in the
802.16n AWD as indicates:]
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…
…
…
…
SMS
Var
iabl
e
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Short message contents up to the size of 140bytes
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Start of multicast indication cycle.
The first superframe is the multicast available
interval and rest superframes are the multicast
May be included when
SMS contents is sent in
idle mode.
Shall be included in HRNetwork in response to
the AAI-RNG-REQ
message where ranging
purpose indication is set
to 0b1110.
Shall be present if needed
to update in HR-Network
New Multicast Group Zone
ID
New Multicast Indication
cycle
Indicates a Multicast Group Zone ID to update in
target HR-BS.
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unavailable interval.
For(j=1;j<=M;j++){
…
If(it is under network reentry
for HO){
New Multicast Group Zone
ID
New Multicast Indication
cycle
…
8 LSB of superframe number
Number of Multicast Group ID and FID (M) to
update in the target HR-BS[1..16]
……
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Indicates a Multicast Group Zone ID to update in
target HR-BS.
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Start of multicast indication cycle.
The first superframe is the multicast available
interval and rest superframes are the multicast
unavailable interval.
8 LSB of superframe number
Number of Multicast Group ID and FID (M) to
update in the T-ABS[1..16]. Mapping of current
Multicast Group ID and FID and new Multicast
Group ID and FID to be updated. Based on the
value of Num of Multicast Group ID and FID to be
updated.
For(j=1;j<=M;j++){
Present if it needs to
update in HR-Network.
…
Shall be included in HRNetwork in response to
the AAI-RNG-REQ
message where ranging
purpose indication is set
to 0b1110.
Shall be present if needed
to update in HR-Network
Present if it needs to be
updated.
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[Remedy3: Add the following row into the second row of Table 714, Section 16.2.3.31, page
31 in the 802.16n AWD as indicates:]
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Multicast Group Zone ID
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Multicast Indication cycle
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HR Multimode indication
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Indicates a Multicast Group Zone ID provided by
this BS.
Shall not be set to “0.”
Start of multicast indication cycle.
The first superframe is the multicast available
interval and rest superframes are the multicast
unavailable interval.
8 LSB of superframe number
Indicates whether current BR/RS is HR-MS acting
as BS/RS or HR-BS acting as RS
0b00: current BS/RS is neither HR-MS
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In HR-Network
Shall be present unless
Multicast Group Zone is
set to “0” in HR-Network
HR Multimode indication
Shall be present in HRNetworks
IEEE C802.16n-11/0176
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[Remedy4: Add the following text in line 10, page 32 in the 802.16n AWD as indicates:]
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Multicast Indication cycle: Indicates multicast indication cycle for the multicast in HR-Network
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[Remedy5: Add the following row into the 5th row of Table 740, Section 16.2.3.47.1, page 33
in the 802.16n AWD as indicates:]
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Information, may be encapsulated in this field
}
}
Multicast Group Zone ID
12
Multicast Indication cycle
8
Indicates a multicast group zone to add where the
connection for associated service flow is valid.
Start of multicast indication cycle.
The first superframe is the multicast available
interval and rest superframes are the multicast
unavailable interval.
Num of Multicast Group ID and FID (M) is the
number of Multicast Group IDs to add [1..16]
Present if needed in HRNetwork
Shall be present if
Multicast Group Zone is
included in this message
and the Multicast
indication cycle is
different from that in
AAI-SCD in HR-Network.
If the value is the same as
that in AAI-SCD, this may
not be included in this
message
Present when ABS
initiates AAI-DSA-REQ
…
…
8 LSB of superframe number
For (i=0; i<Num of
Multicast Group ID and
FID (M); i++) {
…
…
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[Remedy6: Add the following text in line 5, page 34 in the 802.16n AWD as indicates:]
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Multicast Indication cycle: Indicates multicast indication cycle for the multicast in HR-Network
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[Remedy7: Add the following row into the 8th row of Table 741, Section 16.2.3.47.2, page 33
in the 802.16n AWD as indicates:]
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……
…
……
…
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Indicates a multicast group zone to add where the
connection for associated service flow is valid.
Present if needed in HRNetwork
}
Multicast Group Zone ID
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Multicast Indication cycle
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Start of multicast indication cycle.
The first superframe is the multicast available
interval and rest superframes are the multicast
unavailable interval.
Num of Multicast Group ID and FID (M) is the
number of Multicast Group IDs to add [1..16]
Shall be present if
Multicast Group Zone is
included in this message
and the Multicast
indication cycle is
different from that in
AAI-SCD in HR-Network.
If the value is the same as
that in AAI-SCD, this may
not be included in this
message
Present when ABS
initiates AAI-DSA-REQ
…
…
8 LSB of superframe number
For (i=0; i<Num of
Multicast Group ID and
FID (M); i++) {
…
…
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[Remedy8: Add the following row into the 5th row of Table 743, Section 16.2.3.47.4, page 36
in the 802.16n AWD as indicates:]
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……
…
……
…
New Multicast Group Zone
ID
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Indicates a multicast group zone to overwrite where
the connection for associated service flow is valid.
Multicast Indication cycle
8
Start of multicast indication cycle to overwrite.
The first superframe is the multicast available
interval and rest superframes are the multicast
unavailable interval.
Present when ABS
initiates AAI-DSC-REQ
in HR-Network
Shall be present if needed
to update
}
For (i=0; i<Num of
Multicast Group ID and
FID (MC); i++) {
…
…
8 LSB of superframe number
Num of Multicast Group ID and FID (MC) is the
number of Multicast Group IDs to add [1..16]
Present when ABS
initiates AAI-DSA-REQ
…
…
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[Remedy9: Add the following text into Section 6.2.3 in the 802.16n AWD.]
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16.2.3.xz AAI-MG-IND
An HR-BS providing multicast service transmits AAI-MG-IND message in the beginning of available interval
in multicast indication cycle. This message indicates whether there is DL multicast traffic for a specific
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multicast group. There are two formats for the AAI-MG-IND message, indicated by the indication type field. If
the indication type is set to “0,” this message indicates the multicast traffic transmission offset directly.
Otherwise, MGIND bitmap indicates a subgroup of multicast group and further information will be transmitted
by AAI-MT-IND described in 16.2.3.xz+1.
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Table aaa – AAI-MG-IND message field description
Field
Size (bits)
1
Indication type
Value/Description
0b0: full MGID indication
0b1: MGIND+MTIND indication
Condition
If (Indication type == 0b0) {
For(i=0; i<Num_MGID;i++){
Num_MGID is the number of multicast group to indicate
multicast traffic is transmitting.
Range : 0 ~ 32
Multicast Group ID
12
Offset of multicast traffic
4
frame number offset in which the ABS transmits multicast
traffic
Shall be present
}
}Else if(Indication type == 0b1) {
MGIND bitmap
M(=64)
Indicates whether a corresponding subgroup of multicast
group has multicast data to transmit, where the N-th bit of
MGIND bitmap [MSB corresponds to N = 0] corresponds to
MGIDs in a subgroup (212×N/M to 212× (N+1)/M-1)
0: There is no multicast traffic for any of multicast groups in
the corresponding multicast subgroup
1: There is multicast traffic for at least one multicast group in
the corresponding multicast subgroup
For (i=0; i<L; i++) {
Offset of multicast MT-IND message
2
frame number offset in which the ABS transmits MT-IND
message
0b00: first frame of this superframe
0b01: second frame of this superframe
0b10: third frame of this superframe
0b11: fourth frame of this superframe
L equals the number
of bits in MGIND
bitmap whose bit is
set to 1.
Shall be present
}
}
}
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16.2.3.xz+1 AAI-MT-IND
AAI-MT-IND message shall be transmitted at the offset indicated by AAI-MG-IND message described in
16.2.3.xz. Based on the action code in AAI-MT-IND message, HR-MSs may receive multicast traffic or perform
network entry or exit sleep mode.
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Table aaa+1 AAI-MT-IND message field description
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Field
For (i=0; i<L; i++) {
MTIND bitmap
Size (bits)
K(=64)
Value/Description
Indicates whether a corresponding multicast group has
multicast data to transmit, where the Q-th bit of MTIND
bitmap [MSB corresponds to Q = 0] corresponds to MGID in
the subgroup (Q is the value of logK LSB of multicast group
and MSB logM of multicast group is defined by MG-IND
message).
Condition
L equals the number
of bits in MGIND
bitmap whose bit is
set to 1 and whose
offset is the current
frame. The bits are
ordered by the
shortest MSB of
MGIND bitmap.
Shall be present
0: There is no multicast traffic for the corresponding multicast
group
1: There is multicast traffic for the corresponding multicast
group
For(j=0;j<P; j++){
Action code
If (action code bit2 == 1){
Offset of multicast traffic
P equals the number
of bits in MTIND
bitmap whose bit is
set to 1.
3
If bit0 = 1, perform network entry or exit sleep mode
If bit1 = 1, perform ranging procedure with ranging purpose
indication is set to HR multicast service flow update(=0b1110)
If bit2 = 1, receiving multicast traffic
4
frame number offset in which the ABS transmits multicast
traffic
Shall be present
}
}
}
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[Remedy10: Add the following text into the end of Section 17.3.9.1.3 in the 802.16n AWD.]
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17.3.9.1.3 Multicast communication operation in idle state
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HR-BS providing multicast service transmits multicast indication cycle using AAI-SCD and AAI-DSA/AAIDSC messages. The multicast indication cycle is unique to HR multicast group zone and it consists of multicast
available interval and multicast unavailable interval. Multicast available interval is the first superframe of each
multicast indication cycle. In the multicast available interval, the HR-BS providing multicast service transmits
MG-IND message described in 16.2.3.xz and MT-IND message described in 16.2.3.xz+1 during multicast
available interval of HR multicast group zone. MG-IND and MT-IND message are used to indicate
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multicast service establishment/change/release
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whether the multicast traffic is transmitted after those messages are transmitted
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to perform network entry or exit sleep mode to transmit multicast related message to change/release
multicast service and update multicast security key.
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to perform multicast service flow update using ranging procedure
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Multicast indication cycle included in AAI-SCD message is used for multicast service establishment.
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During multicast service establishment/change using DSA/DSC message, new multicast indication cycle may be
transmitted.
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During multicast available interval, HR-BS transmits MG-IND message in the beginning of available interval to
indicate multicast traffic of one or more specific multicast groups will transmit. MG-IND includes an indication
whether MT-IND message will be transmitted. If the MT-IND message is transmitted after transmitting MGIND using frame offset, MGIND bitmap indicates a multicast subgroup which is included in the MT-IND
message. Multicast group is divided into some subgroups (i.e., length of MGIND bitmap) and each subgroup
has following number of multicast groups:
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Number of multicast group in a subgroup = 212/M,
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where M is the length of MGIND bitmap and N-th bit in MGIND bitmap indicates a subgroup of multicast
groups from 212×N/M to 212× (N+1)/M-1.
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MT-IND message is transmitted in the offset included in MG-IND message after transmitting MG-IND message
and it indicates whether multicast traffic of specific multicast group will transmit. The multicast group is
indicated based on the MGIND bitmap in MG-IND message and MTIND bitmap in MT-IND message.
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N-th bit in MGIND bitmap indicates the value of logM MSB of Multicast Group ID and Q-th bit in MTIND
bitmap indicates the value of logK LSB of Multicast Group ID. For the indicated Multicast Group ID, according
to the action code, HR-MSs, member of the Multicast Group, perform network entry or receive multicast traffic.
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[-------------------------------------------------End of Text Proposal----------------------------------------------------]
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