IEEE C802.16m- 09/2750
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
Proposal to specify the processing times for A-MAP relevance and HARQ timing
(16.2.14.2.2)
Date
Submitted
2009-12-30
Source(s)
Mihyun Lee, Jaeweon Cho, Hokyu Choi, Heewon Kang,
Jaehee Cho, Ji-Yun Seol, Keunchul Hwang
mihyun.mac.lee@samsung.com
Samsung Electronics Co., Ltd.
Re:
IEEE 802.16-09/0073, “IEEE 802.16 Working Group Letter Ballot#30b”
Target topic: “IEEE P802.16m/D3, section 16.2.14.2.2”.
Abstract
The contribution proposes to separate a single HARQ processing time parameter Tproc, which is
defined in the current 802.16m/D3, into multiple parameters according to the applied case.
Purpose
To be discussed and adopted by TGm for the 802.16m/D4
Notice
Release
Patent
Policy
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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
<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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IEEE C802.16m- 09/2750
Proposal to specify the processing times for A-MAP relevance and
HARQ timing
(Section 16.2.14.2.2)
Mihyun Lee, Jaeweon Cho, Hokyu Choi, Heewon Kang,
Jaehee Cho, Ji-Yun Seol, Keunchul Hwang
Samsung Electronics
1. Introduction
This contribution proposes a change to the HARQ timing defined in the IEEE P802.16m/D2[1]. In the current
HARQ timing structure, when deciding DL HARQ feedback offset, UL HARQ transmission offset, and UL
HARQ feedback offset, a single processing time is applied to all cases. i.e. a single Tproc parameter is used.
However, each processing requires different functions, as listed below:
•
For DL HARQ burst,
-
Rx processing includes,
•
•
DL A-MAP decoding, DL data burst decoding, ACK/NACK encoding
For UL HARQ burst,
-
Tx processing includes,
•
-
UL A-MAP decoding or ACK/NACK decoding, UL data burst encoding
Rx processing includes,
•
UL data burst decoding, Scheduling, UL A-MAP or ACK/NACK encoding
In addition, processing powers of BS and MS are not the same. So, it is reasonable to apply different processing
time to each case. In this contribution, we propose to separate the single processing time parameter Tproc, which
is defined in the current D3[1], into three parameters according to the applied case: i.e. TDL_Rx_Processing for DL
burst Rx processing time, TUL_Tx_Processing for UL burst Tx processing time, and TUL_Rx_Processing for UL burst Rx
processing.
Also, we propose that the ABS broadcasts these processing times through S-SFH SP1 IE. Since HARQ shall be
enabled for MAC control messages sent on the unicast control connections, AMS should know the processing
times to determine the A-MAP relevance and HARQ timing. I recommend 3 or 4 AAI subframes for each
processing time. These figures show the UL HARQ retransmission delay according to the processing time.
UL HARQ timing when TUL_Tx_processing with 3 AAI subframes and TUL_Rx_processing with 3 AAI subframes are
used supports 5 ms RTT shown below,
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IEEE C802.16m- 09/2750
frame index i
frame index i+1
DL
5:3
0
1
2
UL
3
4
0
1
frame index i+2
DL
2
UL A-A-MAP
0
1
UL
2
3
4
0
UL burst
1
DL
2
0
HF A-MAP
1
2
UL
3
4
0
1
2
UL ReTx
UL HARQ timing when TUL_Tx_processing with 3 AAI subframes and TUL_Rx_processing with 4 AAI subframes are
used supports 10 ms RTT shown below,
5:3
frame index i
DL
0
1
2
3
4
0
UL
1
frame index i+1
DL
2
0
1
2
3
UL A-A-MAP
UL burst
4
0
UL
1
2
frame index i+2
DL
0
1
2
3
HF A-MAP
4
0
UL
1
UL ReTx
[Editor’s note]
This document includes 7 suggested remedies which are distributed in different places.
2. References
[1] IEEE P802.16m/D3, “P802.16m DRAFT Amendment to IEEE Standard for Local and metropolitan area
networks Part 16: Air Interface for Broadband Wireless Access Systems”, 2009-12-08
3
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IEEE C802.16m- 09/2750
3. Proposed Text Changes
[Remedy#1: Add the following text in line 44, page 229, section 16.2.14.2.2]
16.2.14.2.2 A-MAP relevance and HARQ timing
Transmissions of Assignment A-MAP IE, the HARQ subpacket, and the corresponding feedback shall be in
accordance to a pre-defined timing. In UL, retransmission of the HARQ subpacket shall also follow a
pre-defined timing.
Each transmission time is represented by frame index and AAI subframe index. The frame index shall range
from 0 to 3. In FDD, the index of DL or UL AAI subframe shall range from 0 to F-1, where F is the number
of AAI subframes per frame. In TDD, the index of DL AAI subframe shall range from 0 to D-1, where D is
the number of DL AAI subframes per frame, and the index of UL AAI subframe shall range from 0 to U-1,
where U is the number of UL AAI subframes per frame.
To determine A-MAP relevance and HARQ timing, DL HARQ feedback offset z, UL HARQ Tx offset v and
UL HARQ feedback offset w shall be set. In DL HARQ transmission, the DL Rx processing time
TDL_Rx_processing at AMS shall be considered for the DL HARQ feedback offset(z). In UL HARQ transmission,
UL Tx processing time TUL_Tx_Processing at AMS and the UL Rx processing time TUL_Rx_Processing at ABS are
considered for the UL HARQ Tx offset(v) and the UL HARQ feedback offset(w), respectively.
For 5, 10 and 20 MHz channel bandwidth, both TDL_Rx_processing and TUL_Tx_Processing at AMS are 3 AAI
subframes. The TUL_Rx_Processing at ABS is broadcast via S-SFH SP1 IE. For other system bandwidth, the values
are TBD.
[Remedy#2: Modify the text and equation, line 16 ~ 52, page 230, section 16.2.14.2.2.1.1]
DL HARQ feedback offset z shall be set to 1 only if a time gap from completion of the HARQ subpacket
transmission to its feedback time derived with z = 0 is shorter than the data burst processing time Tproc
TDL_Rx_Processing. Otherwise, z shall be set to 0. This rule shall be also applied to the long TTI transmission:

0,
z

1,
if ((ceil( F / 2)  NTTI )  Tproc TDL_Rx_Processing )
else
where NTTI is the number of AAI subframes which a HARQ subpacket spans; i.e., 1 for the default TTI and 4
for the long TTI in FDD. The index m in Table 750 indicates the 1st first AAI subframe which a long TTI
subpacket spans.
<Figure 428> omitted
Figure 428 shows an example of the timing relationship between a DL Basic Assignment A-MAP IE, a DL
HARQ subpacket with the default TTI, corresponding HARQ feedback, and retransmission in FDD frame
structure, for 5, 10 and 20 MHz channel bandwidths. In this example, Tproc is 3. TDL_Rx_Processing is 3 AAI
subframes.
[Remedy #3: Modify the text and equation, line 30 in page 231 ~ line 24 in 232, section 16.2.14.2.2.1.2]
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IEEE C802.16m- 09/2750
UL HARQ transmission offset v shall be set to 1 only if a time gap from completion of the UL Basic
Assignment A-MAP IE transmission to the HARQ subpacket transmission time derived with v = 0 is shorter
than TUL_Tx_Processing. Otherwise, v shall be set to 0:
Tproc TUL_Tx_Processing
)
0, if ((ceil( F / 2)  1) 

v

else
1,
UL HARQ feedback offset w shall be set to 1 only if a time gap from completion of the HARQ subpacket
transmission to its feedback time derived with w = 0 is shorter than the data burst processing time Tproc
TUL_Rx_Processing. Otherwise, w shall be set to 0. This rule shall be also applied to the long TTI transmission

0,
w

1,
if (( floor ( F / 2)  NTTI )  Tproc TUL_Rx_Processing )
else
where NTTI is the number of AAI subframes which a HARQ subpacket spans; i.e., 1 for the default TTI and 4
for the long TTI in FDD. The index m in Table 751 indicates the 1st first AAI subframe which a long TTI
subpacket spans.
<Figure 429> omitted
Error! Reference source not found. shows an example of the timing relationship between a UL Basic
Assignment A-MAP IE, a UL HARQ subpacket with the default TTI, corresponding HARQ feedback and
retransmission in FDD frame structure, for 5, 10 and 20 MHz channel bandwidths. In this example, Tproc is 3.
TUL_Tx_Processing and TUL_Rx_Processing are 3 AAI subframes.
[Remedy #4: Modify the text and equation, line 14~48, page 233, section 16.2.14.2.2.2.1]
DL HARQ feedback offset z shall be set to 1 only if a time gap from completion of the HARQ subpacket
transmission to its feedback time derived with z = 0 is shorter than the data burst processing time Tproc the
TDL_Rx_Processing. Otherwise, z shall be set to 0. This rule shall be also applied to the long TTI transmission:
0,
z
1,
if (( D  m  NTTI  n)  Tproc TDL_Rx_Processing )
else
where NTTI is the number of AAI subframes which a HARQ subpacket spans; i.e., 1 for the default TTI and D
for the long TTI in TDD DL. The index m in Error! Reference source not found. indicates the 1st first AAI
subframe which a long TTI subpacket spans.
<Figure 430> omitted
Error! Reference source not found. shows an example of the timing relationship between a DL Basic
Assignment A-MAP IE, a DL HARQ subpacket with the default TTI, corresponding HARQ feedback and
retransmission in TDD frame structure, for 5, 10 and 20 MHz channel bandwidths. In this example, Tproc is 3.
TDL_Rx_Processing is 3 AAI subframes.
[Remedy#5: Modify the text and equation, line 50 in page 234 ~ line 28 in page 235, section 16.2.14.2.2.2.2]
UL HARQ transmission offset v shall be set to 1 only if a time gap from completion of the UL Assignment
A-MAP IE transmission to the HARQ subpacket transmission time derived with v = 0 is shorter than the data
burst processing time Tproc TUL_Tx_Processing. Otherwise, v shall be set to 0:
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IEEE C802.16m- 09/2750
0,
v
1,
if (( D  l  1  m)  Tproc TUL_Tx_Processing
else
)
UL HARQ feedback offset w shall be set to 1 only if a time gap from completion of the HARQ subpacket
transmission to its feedback time derived with w = 0 is shorter than the data burst processing time Tproc the
TUL_Rx_Processing. Otherwise, w shall be set to 0. This rule shall be also applied to the long TTI transmission
0,
w
1,
if ((U  m  NTTI  l )  Tproc TUL_Rx_Processing )
else
N
where T T I is the number of AAI subframes which a HARQ subpacket spans; i.e., 1 for the default TTI
and U for the long TTI in TDD UL. The index m in Error! Reference source not found. indicates the 1st
first AAI subframe which a long TTI subpacket spans.
<Figure 431 > omitted
Error! Reference source not found. shows an example of the timing reclationship between a UL Basic
Assignment A-MAP IE, a UL HARQ subpacket with the default TTI, corresponding HARQ feedback and
retransmission in TDD frame structure, for 5, 10 and 20 MHz channel bandwidths. In this example, Tproc is 3.
TUL_Tx_Processing and TUL_Rx_Processing are 3 AAI subframes.
[Remedy#6: Modify the equations and the texts in line 26 in page 236 ~ line 37 in page 237, section
16.2.14.2.2.2.3]
0,
z
1,
0,
v
1,
0,
w
1,
if (( D'm' NTTI 'n' )  Tproc TDL_Rx_Processing )
else
if (( D'l '1  m' ) 
else
Tproc TUL_Tx_Processing
)
if ((U 'm' NTTI 'l ' )  Tproc TUL_Rx_Processing )
else
<figure 433 > omitted
<figure 434 > omitted
Error! Reference source not found. and Error! Reference source not found. show examples of the DL
and UL timing relationships between a Assignment A-MAP IE, a HARQ subpacket with the default TTI,
corresponding HARQ feedback and retransmission, for 5, 10 and 20 MHz channel bandwidths. The ratio of
whole DL AAI subframes to whole UL AAI subframes, D' : U' is 5 : 3. In this example, FRAME_OFFSET is
1, UL AAI subframes of the WirelessMAN-OFDMA and the Advanced Air Interface are frequency-division
multiplexed, the ratio of DL to UL AAI subframes for the Advanced Air Interface, D : U is 4 : 3, and Tproc is
3. TDL_Rx_Processing, TUL_Tx_Processing, and TUL_Rx_Processing are 3 AAI subframes. HARQ shall be used for unicast
data traffic in both downlink and uplink. The HARQ shall be based on a stop-and-wait protocol. ABS and
AMS shall be capable of maintaining multiple HARQ channels. DL HARQ channels are identified by HARQ
channel identifier (ACID). UL HARQ channels are identified by both ACID and the index of UL AAI
subframe in which UL HARQ data burst is transmitted. Multiple UL HARQ channels in the same UL AAI
subframe shall be identified by different ACIDs, and UL HARQ channels in different UL AAI subframes
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IEEE C802.16m- 09/2750
shall be identified by the index of UL AAI subframe when the same ACID is addressed to them.Group
Resource Allocation HARQ signaling and timing.
[Remedy #7: Add the following parameter into Table 801 in page 376, section 16.3.6.5.1.2]
Syntax
S-SFH SP1 IE format () {
...
TUL_Rx_Processing
Table 801– S-SFH SP1 IE format
Size (bit)
Notes
Specifies the Rx processing time for UL HARQ
For 5, 10 and 20 MHz channel bandwidth
0b0: 3 AAI subframes
0b1: 4 AAI subframes
1
}
7