PC-A-MAP-IE indexing for 802.16m (16.3.6)

Document Number: C80216m-09/2296Date Submitted: 2009-12-30Source: Yu-Hao Chang, Yih-Shen Chen, Pei-Kai Liao yuhao.chang@mediatek.com, yihshen.chen@mediatek.com Chih-Yuan Lin, Paul Cheng MediaTek

Venue: IEEE Session #65, San Diego, U.S.A.

Re: Base Contribution:

N/APurpose:

To be discussed and adopted by TGm. Notice: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.

Release: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.

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<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 >.

2

Background and MotivationBackground and Motivation• AMS adjusts its transmit power based on its power control comma

nd (or PC-A-MAP-IE) to maintain its link quality and reduce possible interference to other ABS when it is in the close-loop power control mode

• ABS adjusts the output power of AMS based on the received UL references, e.g., UL data or CQI feedback, of the corresponding AMS

• Since PC-A-MAP symbols are formed by different number of PC-A-MAP-IEs and multiple PC-A-MAP symbols are transmitted in the same A-MAP region, it is important for the close-loop power controlled AMS to effectively figure out its PC-A-MAP-IE without much signaling overhead

• By coupling with assignment of UL reference signal, additional explicit assignment might not be necessary– One good reference is FBCH allocation

3

Schemes of PC-A-MAP-IE IndexSchemes of PC-A-MAP-IE Index• Different indexing schemes for PC-A-MAP-IE can be

applied to different A-A-MAP-IE – Explicit signaling scheme

• Specify the complete PC-A-MAP-IE index inside A-A-MAP-IE using a [5]-bit index

• Demand additional capacity inside A-A-MAP-IE

– Implicit signaling scheme• AMS derives its PC-A-MAP-IE location information based on other

known information– Coupling PC-A-MAP-IE index with FBCH allocation

• Suitable for the A-A-MAP-IE whose available bits is limited, e.g., UL basic A-A-MAP-IE and UL individual PA-A-MAP-IE

• We prefer implicit indexing scheme

4

Overview of the Proposed PC-A-MAP-IE Indexing Scheme

• The proposed PC-A-MAP-IE indexing scheme contains the following two modes– Default mode

• Suitable for slow time-varying environment• Implicit indexing scheme for all A-A-MAP-IEs

– Enhanced mode• Provides additional TPC to track the fast channel variation• Explicit indexing scheme for UL GRA-A-MAP-IE while implicit

indexing scheme for UL basic A-A-MAP-IE and UL individual A-A-MAP-IE

5

Implicitly Indexing Scheme in Default Mode

• Periodicity of PC-A-MAP– Same period as FBCH period is not inappropriate– The more frequent PC-A-MAP than FBCH would be

meaningless if there is no UL reference signal for UL SINR estimation

• Therefore, same period with FBCH is what PC-A-MAP can have at most if there is no any other UL reference signal

– The less frequent PC-A-MAP than FBCH would result in lack of information for FBCH power control• Fail to track the environment change

6

Example of the Implicitly Indexing Scheme in Default Mode

• ABS assigns FBCH to AMS#1 in UL subframe#3 with 5ms – Then, PC-A-MAP is automatically assigned in DL #7– Exact location in DL#7 is determined by the order of AMS#1’s

FBCH in UL subframe#3

DLSub-frame

#0

DLSub-frame

#1

DLSub-frame

#2

DLSub-frame

#3

DLSub-frame

#4

DLSub-frame

#5

DLSub-frame

#6

DLSub-frame

#7

i- th frame

ULSub-frame

#0

ULSub-frame

#1

ULSub-frame

#2

ULSub-frame

#3

ULSub-frame

#4

ULSub-frame

#5

ULSub-frame

#6

ULSub-frame

#7

DLSub-frame

#0

DLSub-frame

#1

DLSub-frame

#2

DLSub-frame

#3

DLSub-frame

#4

DLSub-frame

#5

DLSub-frame

#6

DLSub-frame

#7

(i+1)th frame

ULSub-frame

#0

ULSub-frame

#1

ULSub-frame

#2

ULSub-frame

#3

ULSub-frame

#4

ULSub-frame

#5

ULSub-frame

#6

ULSub-frame

#7CQ

I #1

TP

C #

1C

QI #

2

TP

C #

2C

QI #

1

CQ

I #2

Duration2Duration1

7

Assignment Rule Suggestion• FDD Systems

• TDD Systems– TBD

Frame index Subframe indexChannel

indexNote

FBCH Location

i m q

PC-A-MAP IE Location i + floor[ (m+P/2)/N ] (floor(m+P/2)) mod N q

P : period of FBCH (subframe)

N : # of subframes in a frame

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Some Limitation of the Default Mode TPC Scheme

• Periodicity of PC-A-MAP-IE is the same as CQI feedback

• When environment varies quickly, the previously mentioned scheme may not be fast enough to adapt to the channel variation– More frequent TPC is necessary

• Enhanced Mode is recommended

• Index for additional TPC command can be realized in both explicit and implicit ways– Explicit Index: UL GRA-A-MAP-IE– Implicit Index: UL basic A-A-MAP-IE and UL individual PA-A-

MAP-IE– The existence of enhanced TPC can be signaled via a short

MAC control header

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Explicit Indexing for GRA-A-MAP-IE in Enhanced Mode

• Indexing for AMS using UL GRA-A-MAP-IE– A [5]-bit index is used to specify the location of the PC-A-MAP-

IE of each active AMS in the same group– A [5]-bit index is used to specify the location of the PC-A-MAP-

IE of the first active AMS in UL GRA-A-MAP-IE while the other active AMS can find its PC-A-MAP-IE index by shifting the PC-A-MAP-IE index of the first active AMS by a fixed value. The offset value is determined by the order of corresponding AMS within active AMS in the same UL GRA-A-MAP-IE group

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Implicit Indexing for Enhanced Mode• Goal:

– Implicit Indexing is suitable for UL basic A-A-MAP-IE and UL individual PA-A-MAP-IE without much signaling overhead

• Proposed scheme:– PC-A-MAP-IE is mapped onto the logical resource unit (LRU)

according to certain index, which is determined by the MLRU index reserved for the corresponding UL basic A-A-MAP-IE or UL PA-A-MAP-IE

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ABS Behavior of the Implicit Indexing Scheme in Enhanced Mode TPC (1/3)

ABS needs to prepare its A-A-MAP-IE and PC-A-MAP-IE in the following steps

1. A-A-MAP-IE encoded by the same MCS are placed in contiguous MLRUs and formed a group

Within each group, UL A-A-MAP symbols, whose additional power control command are in the same subframe, are mapped onto contiguous MLRUs while the rest of A-A-MAP symbols are placed in the remaining MLRUs reserved for the same group

A-A-MAP Group 1 A-A-MAP Group 2

UL basic A-A-MAP-

IE G1,1

UL PA A-A-MAP-IE

G1,2

A-A-MAP-IE G1,N

UL PA A-A-MAP-IE

G2,1

UL basic A-A-MAP-

IE G2,2

A-A-MAP-IE G1,M

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ABS Behavior of the Implicit Indexing Scheme in Enhanced Mode TPC (2/3)

2. PC-A-MAP index of the associated UL A-A-MAP is determined by the MLRU index reserved for UL A-A-MAP via a known equation

For example, For group 1 and 2, additional PC-A-MAP of the ith AMS is placed in the ith PC-A-

MAP channel reserved for group 1 and 2 UL A-A-MAP, respectively

A-A-MAP Group 1 A-A-MAP Group 2

PC-A-MAP

ReservedGroup 1 Region

Reserved Group 2 Region

Default Mode PC-A-MAP Region

PC-A-MAP

PC-A-MAP

PC-A-MAP

UL basic A-A-MAP-

IE G1,1

UL PA A-A-MAP-IE

G1,2

A-A-MAP-IE G1,N

UL PA A-A-MAP-IE

G2,1

UL basic A-A-MAP-

IE G2,2

A-A-MAP-IE G1,M

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ABS Behavior of the Implicit Indexing Scheme in Enhanced Mode TPC (3/3)

3. To avoid possible collision between implicit indices for additional PC-A-MAP-IE and others, we allocate enhanced mode PC-A-MAP-IE for UL A-A-MAP in a separate region

4. Since enhanced mode happens less often, we may not have to reserve many PC-A-MAP channels for UL A-A-MAP in both group 1 and 2

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AMS Behavior of the Implicit Indexing Scheme in Enhanced Mode TPC

The following steps are required for AMS to identify its additional PC-A-MAP-IE implicitly1. AMS can find its UL A-A-MAP-IE by blind decoding and thus

determine the MLRU index associated with its A-A-MAP-IE

2. The MCS of PC-A-MAP-IE, which determines the size of PC-A-MAP symbol, can be implied by that of the corresponding A-MAP-IE, e.g., UL A-A-MAP-IE, or can be signaled in the broadcast channel– Option: 802.16m specifies clearly the MCS mapping rule

3. With PC-A-MAP IE symbol size, the information of MLRU index and the mapping function available, AMS can determine its PC-A-MAP symbol location. Then it can decode its PC-A-MAP-IE

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Example of the Proposed Enhanced Mode TPC Indexing Scheme

• Two A-A-MAP-IE groups are considered in this example, where Group 1 and 2 contains 5 and 7 A-A-MAP-IEs, respectively

• MCS for Group 1 and 2 is QPSK ¼ and QPSK ½, respectively

• The number of AMS, which needs additional TPC, of Group 1 is 1 while that of Group 2 is 2

• Once AMS finds its UL A-A-MAP-IE, it can determines the MLRU index of its A-A-MAP-IE as 2 in the Group 2

• If 2 PC-A-MAP channels are reserved for each A-A-MAP group, we learn that the desired PC-A-MAP-IE is in the 1st channel of Group 2 region

• The modulation format of PC-A-MAP-IE can be determined by the MCS of the corresponding A-A-MAP, e.g., BPSK is applied to Group 1 while QPSK is applied to Group 2

• AMS can determine the location of PC-A-MAP symbol and then decode the power control command

UL A-A-MAP

other A-A-MAP

other A-A-MAP

other A-A-MAP

UL A-A-MAP

UL A-A-MAP

other A-A-MAP

other A-A-MAP

other A-A-MAP

other A-A-MAP

A-A

-MA

P G

roup 1 (Q

PS

K 1/4)

A-A

-MA

P G

roup 2 (Q

PS

K 1/2)

PC-A-MAP-IE

Empty

EmptyPC-A-MAP-IE

Empty

Empty

Empty

other A-A-MAP

other A-A-MAP

BPSK PC-A-MAP Symbol

Empty PC-A-

MAP Symbol

QPSK PC-A-

MAP Symbol

Empty PC-A-

MAP Symbol

Empty PC-A-

MAP Symbol

Empty PC-A-

MAP Symbol

Empty PC-A-

MAP Symbol

Empty

Empty

PC-A-MAP-IE

Empty PC-A-

MAP Symbol

G1 region

G2 region

Default region

16

Summary

• Default Mode TPC index scheme– Implicit indexing scheme

• PC-A-MAP location is coupled with FBCH allocation

• Enhanced Mode TPC index scheme– Explicit indexing scheme

• GRA-A-MAP-IE

– Implicit indexing scheme• UL basic A-A-MAP-IE and UL PA-A-MAP-IE

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Proposed Text• Insert the following text and Table XX under the table 810- PC-A-MAP IE format of page 3

94 in the section 16.3.6.5.2.3 of D3

Table XX-FDD PC-A-MAP Assignment Location

Frame index Subframe index Channel index

FBCH Location i m q

PC-A-MAP IE Location i + floor[ (m+P/2)/N ] (floor(m+P/2)) mod N q

For FDD systems, when FBCH is assigned to AMS, the corresponding PC-A-MAP follows the assignment

location defined in Table XX. In the table, P is allocation period of Feedback Allocation A-MAP IE (refer to

Table 818-Feedback Allocation A-MAP IE) in terms of subframe and N is the number of subframes in a

frame.

For TDD systems, when FBCH is assigned to AMS, the corresponding PC-A-MAP follows the assignment

location defined in TBD.

When additional PC-A-MAP-IE is necessary, ABS signals the existence of additional TPC using a short

MAC control header in the corresponding DL data packet in the same subframe. The index of additional

PC-A-MAP-IE can be explicitly indicated in GRA-A-MAP-IE or can be implicitly indicated in both UL

basic A-A-MAP-IE and UL individual PA-A-MAP-IE based on the MLRU index reserved for the

corresponding A-A-MAP-IE. The detail implicit indexing scheme for additional PC-A_MAP-IE is FFS.