IEEE C802.16m-09/0889r1
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Proposed IEEE 802.16m Amendment Text on Primary Carrier Change
Date
Submitted
2009-04-27
Source(s)
Juhee Kim, Eunkyung Kim,
E-mail:
Juhee@etri.re.kr
Soojung Jung, Jaesun Cha,
Kwangjae Lim, Hyun Lee, Chulsik Yoon
ETRI
Re:
Category: AWD-New contribution /Area: Multi-Carrier
Abstract
This contribution proposes IEEE 802.16m AWD on Multi-Carrier operation
Purpose
Proposed to be discussed and adopted by TGm for the 802.16 AWD
Notice
Release
Patent
Policy
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Proposed IEEE 802.16m Amendment Text on Primary Carrier Change
Juhee Kim, Eunkyung Kim, Soojung Jung, Jaesun Cha, Kwangjae Lim, Hyun Lee, Chulsik Yoon
ETRI
I. Introduction
This contribution proposes amendment text on the primary carrier change procedure for the WirelessMANOFDMA Advance System with multi-carrier support.
II. New messages for the carrier management
While other actions such as handover and power management in MC operation can be performed with the same
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IEEE C802.16m-09/0889r1
messages as in Single Carrier, the carrier management is an action specified only in MC. Therefore, we suggest
that new messages should be defined for carrier management in Multi-Carrier Operation as follows.
-
AAI_CC-REQ (Carrier Change Request) message
: The AAI_CC-REQ message is transmitted by an AMS to request the active carrier change such as
primary carrier change and secondary carrier activation/deactivation.
-
AAI_CC-CMD (Carrier Change Command) message
: The AAI_CC-CMD message is transmitted by the ABS to command for the AMS to change the
configuration of the active carriers (the primary carrier change, secondary carrier activation/deactivation)
-
AAI_CC-IND (Carrier Change Indication) message
: The AMS shall transmit an AAI_CC-IND message upon reception of AAI_CC-CMD message.
III.
Primary Carrier Change
The ABS may instruct an AMS, through control signaling on the current primary carrier, to change the primary
carrier to other fully configured carrier for load balancing purpose, carriers’ varying channel quality or other
reasons. The primary carrier change can be triggered by ABS or requested by the AMS through the serving
primary carrier. The ABS and AMS may select one of the following procedures for the primary carrier change,
1) Directly change the primary carrier to one of AMS’s active secondary carriers
2) Change the primary carrier after scanning in-active assigned carriers
When the ABS decides to change the primary carrier to one of the AMS’s active carriers (in case of 1)), the
AMS can switch to the target primary carrier directly after it receives a primary carrier change command
message (AAI_CC-CMD). This is because the AMS already maintains synchronized on the target carrier.
The AMS obtains the following information from the received AAI_CC-CMD message,
-
Logical Carrier Index of the target primary carrier
-
Switch time: the time when the AMS shall switch to the target primary carrier and be ready to
communicate with the target primary carrier.
-
Next state of the serving primary carrier
If the ‘Next state of the serving primary carrier’ in the AAI_CC-CMD message is set to 1, the serving primary
carrier shall keep active as the AMS’s secondary carrier. In this case, the old Logical Carrier Index of the target
primary carrier is automatically assigned for a new Logical Carrier Index of the serving primary carrier, if the
AAI_CC-CMD message doesn’t contain an assignment rule. Otherwise, the serving primary carrier shall be
deactivated. In response to the AAI_CC-CMD message, the AMS sends the AAI_CC-IND message to the ABS.
On the switch time, the ABS starts to transmit control signaling and data through the target primary carrier. The
AMS may send an AAI_CC-REQ message in order to request to change its current primary carrier. In this case,
the AAI_CC-REQ message may include a candidate list for new primary carrier.
For the 2) procedure, the ABS may request channel measurement on in-active assigned carriers through
AAI_SCN-RSP message before the primary carrier change. The AAI_SCN-RSP message may include a subset
of the in-active assigned carriers. Upon reception of it, the AMS shall decide how to perform measurement on
the selected carriers. There are two scenarios for the AMS to scan the in-active assigned secondary carriers as
follows,
i) Pause service on one of the active carriers and scan the selected secondary carriers.
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IEEE C802.16m-09/0889r1
ii) Use unused transceivers (when the number of active carriers is less than maximum number of active
carriers, refer to Figure 1)
ABS
0
1
2
3
PCI: PhysiCarrier Index
# of Available Carriers: 5
4
PCI 0 PCI 1 PCI 2 PCI 3 PCI 4
·
·
AMS
Sync & Initial
Ranging
Available Carrier Information
Max # of Active Carriers = 3
PCI 2
·
·
AMS
SBC negotiation
·
·
PCI 2
Other Network
Entry Procedure
·
·
AMS
SC Activation
·
PCI 2 LCI 1: PCI 3
·
·
Transceiver for Primary Carrier
Available Carrier Information
Max # of Active Carriers = 3
- # of Active Carriers = 1
Primary Carrier Information
- PrimCarrier = PCI2 (LCI 0)
Assigned Carrier Information
- AssCarrier : PCI 0, PCI 1, PCI 2, PCI 3
Available Carrier Information
Max # of Active Carriers = 3
- # of Active Carriers = 2
Primary Carrier Information
- PrimCarrier = PCI2 (LCI 0)
Assigned Carrier Information
- AssCarrier : PCI 0, PCI 1, PCI 2, PCI 3
Active Carrier Information
- LCI 0 : PCI 2
- LCI 1 : PCI 3
Transceiver for Active Secondary Carrier
Unused Transceiver
Figure 1 Example of Carrier Management Information
In case of i), the AMS sends AAI_SCN- REQ message to the ABS which includes scanning interval information
and Logical Carrier Index of the active carrier to be used for scanning through AAI_SCN-REQ message. The
rest of the scanning procedure is the same as HO scanning. In case of ii), there is no need of AAI_SCNREQ/RSP transaction. After the AMS finishes the measurement, the AMS reports the scanning results through
AAI_SCN- REP message to the ABS. Upon reception of the measurement information, the ABS determines the
target primary carrier based on load balance, channel quality and so on. If the target primary carrier is already
active, the ABS and the AMS perform the actions described in the above paragraph. Otherwise, the ABS sends
the AAI_CC-CMD message which includes the following information to command the primary carrier change.
-
The Physical Carrier Index of the target primary carrier
-
Switch time; This value is determined by considering synchronization and ranging to the target primary
carrier
-
Next state of the serving primary carrier
-
Ranging information (Optional)
If the ‘Next state of the serving primary carrier’ in the AAI_CC-CMD message is set to 1, the serving primary
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IEEE C802.16m-09/0889r1
carrier shall keep active as the AMS’s secondary carrier with the highest Logical Carrier Index of the active
carriers + 1. Otherwise, the serving primary carrier shall be deactivated after the primary carrier change. In
response to the AAI_CC-CMD message, the AMS sends the AAI_CC-IND message to the ABS. Before switch
time, the AMS performs ranging to the target primary carrier according to ranging information in the AAI_CCCMD message, if needed.
AMS
ABS
0
1
2
3
4
Data Transfer (Primary Carrier LCI 0)
Data Transfer (Active SC LCI 1)
AAI_CC-REQ
AAI_SCN-RSP
AAI_SCN-REQ
AAI_SCN-RSP
Scanning on PCI 1
Scanning on PCI 4
AAI_SCN-REP
AAI_CC-CMD
TargetPC: PCI 1
AAI_CC-IND
Switch time
Ranging
Data Transfer (Primary Carrier LCI 0)
Data Transfer (Active SC LCI 1)
Figure 2 Example of primary carrier change procedure
IV.
Proposed Text
----------------------------------------------------------- Text Start ---------------------------------------------------------------
15.2.4 AAI MAC Management Message
15.2.4.x AAI CC-REQ (Carrier Change Request)
The AAI_CC-REQ message is transmitted by an AMS to request to change the configuration of the active
carriers of the AMS. To specify the requested action, the AAI CC-REQ message shall contain an action field
which takes the following values:
-
Primary carrier change to one of the active carriers
-
Primary carrier change to one of the inactive assigned carriers
-
Secondary carrier activation
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IEEE C802.16m-09/0889r1
-
Secondary carrier deactivation
15.2.4.x AAI CC-CMD (Carrier Change Command)
The AAI_CC-CMD message is transmitted by the ABS to command for the AMS to change the configuration of
the active carriers such as the primary carrier change and the secondary carrier addition/deletion. To distinguish
between the different actions, the AAI CC-CMD message shall contain an action field which takes the following
values:
-
Primary carrier change to one of the active carriers
-
Primary carrier change to one of the inactive assigned carriers
-
Secondary carrier activation
-
Secondary carrier deactivation
15.2.4.x AAI CC-IND (Carrier Change Indication)
The AMS shall transmit an AAI_CC-IND message upon reception of AAI_CC-CMD message
15.2.x.x.x Primary Carrier Change
The ABS may instruct an AMS, through control signaling on the current primary carrier, to change the primary
carrier to other fully configured carrier for load balancing purpose, carriers’ varying channel quality or other
reasons. The primary carrier change can be triggered by ABS or requested by the AMS through the serving
primary carrier. The ABS and AMS may select one of the following procedures for the primary carrier change,
1) Directly change the primary carrier to one of AMS’s active secondary carriers
2) Change the primary carrier after scanning in-active carriers
When the ABS decides to change the primary carrier to one of the AMS’s active carriers (in case of 1)), the
AMS can switch to the target primary carrier directly after it receives a primary carrier change command
message (AAI_CC-CMD). This is because the AMS already maintains synchronized on the target carrier.
The AMS obtains the following information from the received AAI_CC-CMD message,
-
Logical Carrier Index of the target primary carrier
-
Switch time: the time when the AMS shall switch to the target primary carrier and be ready to
communicate with the target primary carrier.
-
Next state of the serving primary carrier
If the ‘Next state of the serving primary carrier’ in the AAI_CC-CMD message is set to 1, the serving primary
carrier shall keep active as the AMS’s secondary carrier. In this case, the Logical Carrier Indices are
automatically exchanged between the serving primary carrier and the target primary carrier if the AAI_CC-CMD
message doesn’t contain an assignment rule. If it is set to 0, the serving primary carrier shall be deactivated. In
response to the AAI_CC-CMD message, the AMS sends an AAI_CC-IND message to the ABS. On the switch
time, the ABS starts to transmit control signaling and data through the target primary carrier. The AMS may
send an AAI_CC-REQ message in order to request to change its current primary carrier. In this case, the
AAI_CC-REQ message may include a candidate list for new primary carrier.
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IEEE C802.16m-09/0889r1
For the 2) procedure, the ABS may request channel measurement on in-active assigned carriers through
AAI_SCN-RSP message before the primary carrier change. The AAI_SCN-RSP message may include a subset
of the in-active assigned carriers. Upon reception of it, the AMS shall decide how to perform measurement on
the selected carriers. There are two scenarios for the AMS to scan the in-active assigned secondary carriers as
follows,
i) Pause service on one of the active carriers and scan the selected secondary carriers.
ii) Use unused transceivers (when the number of active carriers is less than maximum number of active
carriers)
In case of i), the AMS sends an AAI_SCN- REQ message to the ABS which includes scanning interval
information and Logical Carrier Index of the active carrier to be used for scanning through the AAI_SCN-REQ
message. The rest of the scanning procedure is the same as HO scanning. In case of ii), there is no need of
AAI_SCN-REQ/RSP transaction. After the AMS finishes the measurement, the AMS reports the scanning
results through an AAI_SCN- REP message to the ABS. Upon reception of the measurement information, the
ABS determines the target primary carrier based on load balance, channel quality and so on. If the target primary
carrier is already active, the ABS and the AMS perform the actions described in the above paragraph. Otherwise,
the ABS sends the AAI_CC-CMD message which includes the following information to command the primary
carrier change.
-
Physical Carrier Index of the target primary carrier
-
Switch time; This value is determined by considering synchronization and ranging to the target primary
carrier
-
Next state of the serving primary carrier
-
Ranging information (optional)
If the ‘Next state of the serving primary carrier’ in the AAI_CC-CMD message is set to 1, the serving primary
carrier shall keep active as the AMS’s secondary carrier with the highest Logical Carrier Index of the active
carriers + 1. Otherwise, the serving primary carrier shall be deactivated after the primary carrier change. In
response to the AAI_CC-CMD message, the AMS sends an AAI_CC-IND message to the ABS. Before switch
time, the AMS performs ranging to the target primary carrier according to ranging information in the AAI_CCCMD message, if needed.
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IEEE C802.16m-09/0889r1
AMS
ABS
0
1
2
3
4
Data Transfer (Primary Carrier LCI 0)
Data Transfer (Active SC LCI 1)
AAI_CC-REQ
AAI_SCN-RSP
AAI_SCN-REQ
AAI_SCN-RSP
Scanning on PCI 1
Scanning on PCI 4
AAI_SCN-REP
AAI_CC-CMD
TargetPC: PCI 1
AAI_CC-IND
Switch time
Ranging
Data Transfer (Primary Carrier LCI 0)
Data Transfer (Active SC LCI 1)
Figure x Example of primary carrier change procedure
----------------------------------------------------------- Text End ---------------------------------------------------------------
7