IEEE C802.16m-09/2411r1
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Proposed Text Related to primary carrier change for the IEEE 802.16m/D2 (15.2.8.2.11)
Date
Submitted
2009-11-06
Source(s)
Eunjong Lee, Kiseon Ryu, Youngsoo Yuk,
Ronny Yongho Kim
Voice : +82-31-450-1876
LG Electronics
E-mail:
mehappy3@lge.com,
sixs@lge.com, ronnykim@lge.com
Lei Wang
leiw@billeigean.com
ksryu@lge.com,
InterDigital Communications, LLC
Re:
IEEE 802.16 Working Group Letter Ballot #30a
Abstract
The contribution proposes the text of multi-carrier operation to be included in the 802.16m
amendment.
Purpose
To be discussed and adopted by TGm for the 802.16m DRAFT amendment.
Notice
Release
Patent
Policy
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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
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<http://standards.ieee.org/guides/bylaws/sect6-7.html#6> and
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Proposed Text Related to primary carrier change for the IEEE
802.16m/D2 (15.2.8.2.11)
Eunjong Lee, Kiseon Ryu, Youngsoo Yuk and Ronny Yongho Kim
LG Electronics
Lei Wang
InterDigital Communications, LLC
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IEEE C802.16m-09/2411r1
1. Introduction
This contribution clarifies the carrier management procedures related to AAI_CM-CMD/IND messages.
2. Discussions
In the carrier management procedure, the AAI_CM-CMD message is used for the ABS to instruct the AMS to
perform certain actions, and then the AAI-CM-IND message is used for the AMS to respond to the ABS after
received an AAI_CM-CMD with carrier management action specific responses, i.e.,
a) If the carrier management action is secondary carrier management, i.e., secondary carrier activation /
deactivation, then the AAI_CM-IND message is sent by the AMS to confirm with the ABS that the AMS
has successfully activated /deactivated the carriers listed in the AAI_CM-CMD message;
b) If the carrier management action is primary carrier change, then the AAI_CM_IND is sent by the AMS
to confirm with the ABS the reception of the primary carrier change AAI_CM-CMD message, while the
primary carrier change action will be actually executed at the “action time” given in the AAI_CM-CMD
message;
c) If the carrier management action is carrier switching, similarly, then the AAI_CM_IND is sent by the
AMS to confirm with the ABS the reception of the carrier switching AAI_CM-CMD message, while the
carrier switching action will be actually executed at the “start time” given in the AAI_CM-CMD
message.
Note that current procedure is not clear what if the AMS cannot successfully complete the given actions as
instructed by the AAI_CM-CMD from the ABS.
In the mobile environment, the assigned but not-activated secondary carriers may experience significant
changes after the secondary carrier assignment, so that the carrier management actions given in the
AAI_CM-CMD from the ABS, e.g., secondary carrier activation, primary carrier change, or secondary carrier
switching, may not be completed successfully. The current carrier management procedures do not have any
mechanisms for the AMS to report any exceptions in its execution of the action requested by the
AAI_CM-CMD message. This is problematic, particularly, to the periodic carrier switching case. Therefore, we
propose to modify the AAI_CM-IND by adding the info field to indicate the execution status of the AMS for the
action requested by the ABS in the AAI_CM-CMD message and clarify the carrier management procedures.
In addition, we’d like to clarify the action time of primary carrier change procedure. Figure 1 illustrates the
procedure for primary carrier change based on the description in 15.2.8.2.11.2 Primary Carrier Change of
AWD [6]. When an AMS receives the AAI_CM-CMD MAC control message, the AMS transmits the
AAI_CM-IND MAC control message and the AMS changes its primary carrier to the target fully configured
carrier at action time specified by the ABS. However, if the action time is set to an insufficient value for
ensuring the reception of AAI_CM-IND, the ABS can misunderstand that the AMS fails the reception of
AAI_CM-CMD or rejects action directed by AAI_CM-CMD although the AMS is ready to transmit the
AAI_CM-IND message. As a result, this leads to the failure of primary carrier change. Figure 2 shows an
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IEEE C802.16m-09/2411r1
example for the error case of primary carrier change procedure.
AMS
S-carrier
ABS (common MAC)
S-carrier
T-carrier
T-carrier
Management Message & Data
AAI_CM-CMD
D
Data communication
Data communication
Action time
AAI_CM
-IN
Management Message & Data
Action time
Figure 1. Primary carrier change procedure based on current AWD
AMS
S-carrier
ABS (common MAC)
S-carrier
T-carrier
T-carrier
Management Message & Data
Data communication
Action time
AAI_CM
-IND
(Action
co d e 0 1
)
Action time
(Action c
MD
AAI_CM-C
ange )
carrier ch
ry
a
m
ri
P
:
1
0
e
d
o
If the ABS doesn’t receive the AAI_CM_IND, ABS
regards that the primary carrier change procedure fails.
Figure 2. An example for the error case of current primary carrier change procedure
In order to provide clearer procedure of primary carrier change, we propose to clarify the action time defined in
AAI_CM-CMD. That is, in our clarified procedure, the ABS shall start the retransmission timer for
AAI_CM-CMD when transmitting the AAI_CM-CMD message, as described in 15.2.21 MAC Management
Reliability of current AWD [6] and the action time included in AAI_CM-CMD shall be set to the value more
than the retransmission timer. If the ABS receives the AAI_CM-IND message before the expiration of the
retransmission timer, ABS stops the timer and performs the corresponding procedure. If the action execution
status is set to ‘0’, the ABS will perform the procedure directed by the action code. If the action execution status
is set to ‘1’ or the timer is expired, the ABS may retransmit the AAI_CM-CMD message. If the AAI_CM-CMD
is retransmitted, the retransmission timer shall restart and the action time included in AAI_CM-CMD shall be
also modified based on the restarted retransmission timer. In the same manner with action time, the start time of
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IEEE C802.16m-09/2411r1
the carrier switching procedure should be also clarified in the AAI_CM-CMD message.
If the local NACK is enabled for AAI_CM-IND, the AMS can detect the failure of the corresponding procedure
via the local NACK when the HARQ process fails. In addition, if the AMS requests ABS to send a MAC layer
acknowledgement for the control message by setting the polling bit in FEH, the AMS can also detect the
success or failure of the corresponding procedure through AAI_MSG_ACK message or Message ACK EH. For
the reliable transmission of the AAI_CM-CMD and AAI_CM-IND, it shall follow the procedure described in
section 15.2.21 MAC Management Reliability of AWD [6].
ABS (common MAC)
S-carrier
T-carrier
AMS
S-carrier
T-carrier
Management Message & Data
Start the retx. Timer
for AAI_CM-CMD
Action time
timeout
D
AAI_CM-CM
AAI_CM-IN
D
(action exec
ution status
: 0)
Data communication
Data communication
Management Message & Data
Action time
Figure 3. Proposed Primary carrier change procedure
3. References
[1] IEEE 802.16m-07/002r8, “802.16m System Requirements Document (SRD)”
[2] IEEE 802.16m-09/0034, “The Draft IEEE 802.16m System Description Document”
[3] IEEE P802.16 Rev2 / D9, “Draft IEEE Standard for Local and Metropolitan Area Networks: Air Interface
for Broadband Wireless Access,” January. 2009.
[4] IEEE 802.16m-08/043, “Style guide for writing the IEEE 802.16m amendment”
[5] IEEE 802.16m-09/0010r2, “IEEE 802.16m Amendment Working Document”
[6] IEEE P802.16m/D2, “DRAFT Amendment to IEEE Standard for Local and metropolitan area networks”
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IEEE C802.16m-09/2411r1
4. Text proposal for the 802.16m DRAFT amendment
-----------------------------------------------------------Start of the Text--------------------------------------------------------[Insert the text at line 8 on page 160 as follows:]
15.2.8.2.11.2 Primary Carrier Change
The ABS may instruct the AMS, through the AAI_CM-CMD MAC control message on the current primary
carrier, to change its primary carrier to one of the assigned fully configured carriers within the same ABS for
load balancing purpose, carriers' varying channel quality or other reasons. When an AMS receives the
AAI_CM-CMD MAC control message, the AMS transmits the AAI_CM-IND MAC control message to
confirm with the ABS the reception of the AAI_CM-CMD message and also to indicate whether or not the
AMS accepts the requested primary carrier change action. If the AMS accepts the requested primary carrier
change action, the AMS switches to the target fully configured carrier at action time specified by the ABS. The
action time in AAI_CM-CMD shall be set to the value more than the retransmission timer for AAI_CM-CMD
message. If the target carrier is one of the active secondary carriers of the AMS, the AMS may receive data and
control signal on the target carrier immediately after switching. Otherwise, the AMS may transmit a bandwidth
request to notify its readiness of the target carrier to the ABS. If the AMS has UL data to be transmitted, it
follows the normal bandwidth request procedure. If the AMS does not have any UL data, it transmits a
bandwidth request with zero bandwidth request size. The ABS may transmit data and control signal after a
bandwidth request is received from the AMS through the target primary carrier. Given that a common MAC
manages both serving and target primary carriers, network re-entry procedures at the target primary carrier is
not required. The ABS may provide the system information of the target primary carrier that is different from
the serving primary carrier via the serving primary carrier. The logical carrier indices of the serving and target
primary carrier are swapped after the primary carrier change. The ABS may direct an AMS to change the
primary carrier without scanning.
[Insert the text at line 48 on page 160 as follows:]
15.2.8.2.11.3 Carrier switching mode
Primary to secondary carrier switching in multicarrier mode is supported when secondary carrier is partially
configured. The carrier switching between a primary carrier and a secondary carrier can be periodic or
event-triggered with timing parameters defined by the AAI_CM-CMD MAC control message on the primary
carrier. When an AMS switches to a secondary carrier, its primary carrier may provide basic information such
as timing and frequency adjustment to help with AMS's with fast synchronization with the secondary carrier.
When an AMS receives the AAI_CM-CMD MAC control message, the AMS transmits AAI_CM-IND MAC
control message to confirm with the ABS the reception of the AAI_CM-CMD message and also to indicate
whether or not the AMS accepts the requested carrier switching action. If the AMS accepts the requested carrier
switching action, and the AMS switches to the secondary carrier at start time specified by ABS, as directed in
the AAI_CM-CMD MAC control message. The start time in AAI_CM-CMD shall be set to the value more than
the retransmission timer for AAI_CM-CMD message.
[Insert the text at line 7 on page 161 as follows:]
15.2.8.2.11.4 MAC Control Messages for Carrier Management
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15.2.8.2.11.4.1 Carrier Management Command (AAI_CM-CMD) MAC control message
An AAI_CM-CMD message shall be transmitted by an ABS to initiate a carrier management procedure, such as
carrier activation/deactivation, primary carrier change or carrier switching. To Respond to a received
AAI_CM-CMD MAC management message, the AMS shall transmit the AAI_CM-IND MAC management
message.
The ABS shall start retransmission timer for the AAI_CM-CMD when transmitting the AAI_CM-CMD
message as described in <<15.2.21>>. If the ABS successfully receives the AAI_CM-IND message indicating
the action execution status ‘0’ before expiration of the retransmission timer, ABS stops the timer and performs
the procedure corresponding to the action code. If the retransmission timer is expired or the ABS receives the
AAI_CM-IND message indicating the action execution status ‘1’, the ABS may retransmit AAI_CM-CMD
message.
The format of the AAI_CM-CMD MAC control message is shown in Table 726.
Table 726—AAI_CM-CMD MAC Management Message Format
Field
AAI_Carrier Management Command message format(){
Control Message Type
Action code
Size (bit)
8
2
If (Action code == 00){
Indication Type
If (Indication Type #0 == 1)
Num of target carrier
For(i=0; i< Num of target carrier; i++){
Target carrier index
2
00: Secondary carrier management
01: Primary carrier change
10: Carrier switching
11: reserved
This message is for secondary carrier activation and/or
deactivation
For Activation and/or Deactivation
Bit #0: ‘0’: No action, ‘1’: Activation
Bit #1: ‘0’: No action, ‘1’: Deactivation
The number of newly activated carrier(s)
[TBD]
Target carrier index for activation
‘0’: Both DL/UL are activated
‘1’: DL is activated but UL is not activated
Ranging indicator for target carrier
‘0’: No ranging is required for the target carrier
‘1’: Periodic ranging is required for the target carrier
1
Ranging indicator
1
Deactivation of DL/UL
AAI_CM-CMD
[TBD]
Activation of DL/UL
}
}
If (Indication Type #1 == 1){
Num of target carrier
For(i=0; i< Num of target carrier; i++){
Target carrier index
Description
[TBD]
The number of deactivated carrier(s)
[TBD]
Target carrier index for deactivation
‘0’: Both DL/UL are deactivated
‘1’: UL is deactivated but DL is kept active
1
}
}
}
If (Action code == 01){
This message is for primary carrier change.
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Target carrier index
[TBD]
Action Time
[TBD]
Next state of serving primary carrier
}
If (Action code == 10){
Target carrier index
Switching mode
1
[TBD]
1
Start time
[TBD]
Switching interval
[TBD]
Target carrier index for primary carrier change
LSB bits of Superframe number at the time to switch to the
target carrier.
This value shall be set to the value more than the
retransmission timer for AAI_CM-CMD message.
‘0’: Serving carrier will be deactivated after primary carrier
change
‘1’: Serving carrier is kept active after primary carrier
change
This message is for secondary carrier switching.
Target carrier index for carrier switching
Periodic or event-triggered switching
0: Periodic switching
1: Event-triggered switching
TBD LSB bits of superframe number at the start time of
carrier switching.
This value shall be set to the value more than the
retransmission timer for AAI_CM-CMD message.
Number of superframes during which an AMS stays at the
target secondary carrier before returning to the primary
carrier
If (Switching mode == 0){
Switching period
[TBD]
Number of superframes between consecutive switching
interval
}
}
}
15.2.8.2.11.4.2 Carrier Management Indication (AAI_CM-IND) MAC control message
An AAI_CM-IND message shall be transmitted by an AMS as a response to a received AAI_CM-CMD
message. In order to ensure the reliability of this message, the AMS shall follow the procedure described in
<<15.2.21>> when transmitting this message.
If the Action Code = 0b00, i.e., for the secondary carrier management, the AAI_CM-IND message is sent by the
AMS to the ABS to indicate the execution status of the secondary carrier management action, i.e., secondary
carrier activation / deactivation, requested in the AAI_CM-CMD message. If the Action Status = 0b0, it
indicates that the AMS has successfully executed the requested secondary carrier activation / deactivation action.
If the Action Status = 0b1, then it indicates the secondary activation /deactivation action was not successful,
then an exception code is also presented in the AAI_CM-IND message to provide further information of the
exception.
If the Action Code = 0b01 or 0b10, i.e., primary carrier change or carrier switching, the AAI_CM-IND message
is sent by the AMS to the ABS to confirm the reception of the AAI_CM-CMD message and also provide an
indication through the 1-bit Action Status field to indicate whether or not the requested action is accepted by the
AMS. If the Action Status = 0b0, it indicates that the AMS accepts the requested primary carrier change or
carrier switching as given in the AAI_CM-CMD message, and the AMS will execute the requested action at the
“Action Time” if the requested action is primary carrier change or at the “Start Time” if the requested action is
carrier switching. If the Action Status = 0b1, it indicates that the AMS rejects the requested action due to
exceptions, where an exception code is followed to provide further information of the exception. After the AMS
accepts the requested action, at the Action Time for primary carrier change or at the Start Time for carrier
switching, if the AMS cannot successfully complete the requested action, then the AMS may send an
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IEEE C802.16m-09/2411r1
unsolicited AAI_CM-IND message to the ABS on the serving primary carrier to indicate the action execution
failure by setting the Action Status = 0b1 and a pre-defined exception code [TBD] indicating the execution
failure.
The format of the AAI_CM-IND MAC control message is shown in Table 727.
Table 727—AAI_CM-IND MAC Control Message Format
Field
Size (bit)
Description
Control message type
Action code
8
2
Action Status
1
AAI_CM-IND
0b00 : Secondary carrier management
0b01: Primary carrier change
0b10: Carrier switching
0b11: reserved
0b0: completed successfully if action code = 0b00; or
accept the requested action if action code = 0b01 or
0b10
0b1: not completed successfully if action code = 0b00;
or reject the requested action due to exception if action
code = 0b01 or 0b10
AAI_Carrier Management-Indication message format(){
If (Action Status == 1) {
Exception code
[TBD]
The code to identify the reason and/or details of the
exception.
}
}
-----------------------------------------------------------End of the Text---------------------------------------------------------
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