Transcript IEEE C802.16m-09/1535r2

User Bitmap reconfiguration in Group resource allocation
Document Number: IEEE C802.16m-09/1535r2
Date Submitted: 2009-07-06
Source:
Jeongki Kim,
Youngsoo Yuk,
Kiseon Ryu,
Ronny Yongho Kim
E-mail: [email protected], [email protected], [email protected], [email protected]
LG Electronics
Re: Category: AWD comments / Area: Chapter 15.2.8 (Group Resource allocation) and Chapter 15.3.6 (DL-CTRL)
“Comments on AWD 15.2.8 Group Resource Allocation and 15.3.6 DL-CTRL”
Purpose:
To be discussed and adopted in 802.16m AWD
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Introduction
• In GRA A-MAP IE, User Bitmap is used to signal which users
are scheduled in the frame
– If a user is scheduled in the frame, the corresponding bit will be set to 1
• When an AMS is added to a group, the ABS allocates a User
Bitmap index to the AMS
• When an AMS is deleted from a group
– Option 1: Variable user bitmap
• If necessary, AMSs belonging to the group will shift their user bitmap
indices
– Option 2: Fixed user bitmap
• AMSs belonging to the group don’t shift their user bitmap indices when
there are deleted users in the group
Motivation
• Option 1: Variable user bitmap
– If an AMS losses the A-MAP IE,
it results in ambiguity in index.
Need a A-MAP error handling
procedure
• E.g.) Need a Shared NAK
channel or ACK channel
– Implementation is complex
AMS
User Bitmap
AMS1 AMS2 AMS3 AMS4 AMS5 AMS6 AMS7 AMS8
Shifting
User Bitmap
AMS1 AMS2 AMS4 AMS5 AMS7 AMS8
• Option 2: Fixed user bitmap
Option 1
– If there are many holes in User
Bitmap due to deletion of users, it
results in resource wastage
• E.g.) Worst case: User Bitmap
size = 16, even though only two
AMSs (AMS 1, AMS16) belong
to the group
Deleted users
AMS
User Bitmap
Deleted users
AMS1 AMS2 AMS3 AMS4 AMS5 AMS6 AMS7 AMS8
AMS9
AMS
10
AMS
11
AMS
12
AMS
13
Option 2
AMS
14
AMS
15
AMS
16
User Bitmap reconfiguration
• Use the semi-static User Bitmap
– ABS reconfigures the User Bitmap when the User Bitmap needs to be
reconfigured from large size to small size
• E.g.) User Bitmap size: 32 -> 16, 16-> 8, 8->4
• This is an implementation issue
– ABS includes the information related to user bitmap reconfiguration in GRA
A-MAP IE
• GRA A-MAP IE includes
– Shifting indicator: Indicates whether there are User Bitmap indices
which should be shifted at this frame and indicates that the size of User
Bitmap is changed from large size to small size
– User Bitmap size: Indicates the size of User Bitmap or the size of
scheduled User Bitmap.
• If Shifting indicator is set to 1, it indicates the size of User Bitmap.
Otherwise, it indicates the size of scheduled User Bitmap
• [0b00: 4, 0b01: 8, 0b10: 12, 0b11: 16] or [0b00: 8, 0b01: 16, 0b10: 24,
0b11: 32]
– User Bitmap: Indicates the scheduled and unscheduled AMSs
belonging to the Group
• This is included in the GRA A-MAP IE only if Shifting indicator is set to 1
User Bitmap reconfiguration
– Retransmission flag
• Indicates whether the GRA A-MAP including User Bitmap is retransmitted
– 0: The TX of GRA A-MAP including User Bitmap is the first transmission
– 1: The GRA A-MAP including User Bitmap is retransmitted. That is, the User Bitmap
has the size and structure of the previous User Bitmap
• ABS will store the previous User Bitmap information until the AMSs which User
Bitmap should be reconfigured receives the User Bitmap successfully
– ReTx Bitmap
• This field will be included only if retransmission flag is set to 1. Indicates which AMSs among
AMSs which should shift their User bitmap indices in User Bitmap should shift their User
bitmap indices at this frame. The size of ReTx Bitmap equals the number of AMSs which
should shift their User Bitmap indices in User Bitmap .
– Scheduled User Bitmap: Indicates the scheduled AMSs in a group
• If shifting indicator is 0, the size of this Bitmap equals the User Bitmap size
• If shifting indicator is 1, the size of this Bitmap equals the number of 1s in User Bitmap.
– Deletion indicator: Indicates whether there are one or more AMSs are deleted from the
group
– Deletion Bitmap: Indicates deleted AMSs at this frame.
• If shifting indicator is 1 and retransmission flag is 0, Size equals number of 0’s in User Bitmap.
[Otherwise, Size equals number of 0’s in scheduled user bitmap] or [Size equals number of 1’s
in scheduled user bitmap]
Example (1/2)
•When the User Bitmap size is reduced from 8
to 4.
Deletion and initial shifting (option 1)
Deletion
Bitmap
( Deleted
AMSs)
0
AMS
#1
AMS
#2
AMS
#3
AMS
#4
AMS
#5
AMS
#6
AMS
#7
AMS
#8
1
1
0
0
1
0
1
0
0
1
0
1
0
0
1
UL HARQ feedback
channel for UL GRA
A-MAP IE
A_I
A_I
A_I
A_I
A_I
A_d
A_d
* A_I: ACK for DL/UL GRA A-MAP IE
* A_d: ACK for DL data burst
Scheduled
AMS
Resource
Hole
Shifting
AMS
Deleted
AMS
User Btimap
(Scheduled +
Unscheduled
AMSs)
Scheduled
User Bitmap
(Scheduled +
AMSs)
UL HARQ
feedback
channel for
DL GRA AMAP IE
Example (2/2)
•AMS #5 did not receive the first GRA A-MAP
IE including the User Bitmap
Deletion and Shifting retransmission
(option1)
AMS
#1
AMS
#2
AMS
#3
AMS
#4
AMS
#5
AMS
#6
AMS
#7
AMS
#8
1
1
0
0
1
0
1
0
ReTx
Bitmap
1
0
1
0
0
1
0
1
UL HARQ feedback
channel for UL GRA
A-MAP IE
A_I
A_I
A_I
A_I
User Btimap
(Scheduled +
Unscheduled
+ Deleted
AMSs)
Scheduled
User Bitmap
(Scheduled +
Deleted
AMSs)
Deletion
Bitmap
( Deleted
AMSs)
A_d
A_d
UL HARQ
feedback
channel for
DL GRA AMAP IE
* A_I: ACK for DL/UL GRA A-MAP IE
* A_d: ACK for DL data burst
Scheduled
AMS
Resource
Hole
Shifting AMS
Shifting AMS
at current
frame
Deleted
AMS
Proposed AWD text Change #1
•15.3.6.5.2.5 Group Resource Allocation A-MAP IE
- Adopt
the proposed text # 1 in CIEEE802.16m-09_1532 or the latest
revision of the contribution.
Proposed AWD text Change #2
Adopt the proposed text # 3 in CIEEE802.16m-09_1533 or the
latest revision of the contribution.
•