IEEE C802.16m-10/0784
Project
IEEE 802.16 Broadband Wireless Access Working Group <http://ieee802.org/16>
Title
ARQ Reset Changes (16.2.13.5.4)
Date
Submitted
2010-07-09
Source(s)
Anil Agiwal, Youngbin Chang, Rakesh anilag@samsung.com, yb.chang@samsung.com,
Taori, Jungje Son
*<http://standards.ieee.org/faqs/affiliationFAQ.h
Samsung Electronics
tml
Re:
Sponsor Ballot on the Draft Amendment (IEEE P802.16m/D6). Topic: ARQ (Section
16.2.13.5.4)
Abstract
This contribution proposes changes to ARQ Reset procedure
Purpose
Notice
Copyright
Policy
Patent
Policy
To be discussed and adopted by TGm for P802.16m/D7.
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.
The contributor is familiar with the IEEE-SA Copyright Policy
<http://standards.ieee.org/IPR/copyrightpolicy.html>.
The contributor is familiar with the IEEE-SA Patent Policy and Procedures:
<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>.
1
IEEE C802.16m-10/0784
ARQ Reset
Anil Agiwal, Youngbin Chang, Rakesh Taori, Jungje Son
Samsung Electronics
1 Introduction
In the ARQ reset procedure defined in D6 specification [1], ARQ receiver can receive the ARQ packets which
were transmitted by ARQ transmitter before the transmission of ARQ reset because of HARQ. For example
consider the sequence:
a) Transmitter sends ARQ packets
b) Transmitter initiates ARQ reset and disables transmission of ARQ packets
c) Transmitter sends ARQ reset
The ARQ packets in the ongoing HARQ transmissions at the time of sending ARQ reset message, can be
received by the receiver after receiving the ARQ reset message and after it has reset its windows. This will lead
to discarding of new packets as duplicates once the new ARQ packet transmissions are initiated by the
transmitter. In some cases it can also lead to combination of two SDU fragments, one from old transmission and
one for new transmission leading to delivery of incorrect SDU to upper layer.
2 Proposed Solution
To avoid the above problem, during the ARQ reset, the ARQ windows at the transmitter and receiver should
start from SN, which is not part of the transmitter’s ARQ window. This way all the new transmissions will be
having different SNs with respect to older transmissions. The older transmissions received after ARQ reset will
get discarded as out of window at the receiver.
3 Proposed text
[Change 1: Modify the text on page 359, section 16.2.13.5.4, lines 4 -11 as follows]
16.2.13.5.4 ARQ Reset procedure
The ARQ reset procedures defined in figures 50 xxx and yyy 51(see 6.3.4.6.2) shall be supported by both the
ARQ receiver and ARQ transmitter. Each side (receiver or transmitter) may initiate an ARQ reset procedure
when ARQ Synchronization loss (see <<15.3.8.7.5>> 16.2.13.5.5) happens or for any other implementation
specific reason. When ARQ reset error happens during the ARQ reset procedure, the ABS or AMS may
reinitialize its MAC.
[Change 2: Add Figures xxx and Figures yyy as shown below after 16.2.13.5.4]
2
IEEE C802.16m-10/0784
ARQ Transmitter
ARQ Receiver
Disable ARQ block (re) transmission
and stop the running timers
ARQ Reset Type = 0x0
Disable Reception, stop all running
timers and ARQ feedback
generation
Set
ARQ_WINDOW_START_SNARQ_Reset =
(ARQ_TX_WINDOW_START_SN +
ARQ_WINDOW_SIZE) mod
(ARQ_SN_MODULUS)
ARQ_RX_WINDOW_START =
ARQ_WINDOW_START_SNARQ_Reset
Send ARQ Reset Type = 0x0, with
ARQ_WINDOW_START_SNARQ_Reset
ARQ_RX_HIGHEST_SN =
ARQ_WINDOW_START_SNARQ_Reset
Set T22
Discard all incomplete SDUs
Wait for ARQ Reset Type = 0x1
Enable reception
Timeout T22
ARQ Reset Type = 0x1 or 0x2
Send ARQ Reset Type = 0x1
No
Retries
exhausted
Yes
ARQ Reset
Error
Clear T22
End ARQ Reset
ARQ_TX_WINDOW_START =
ARQ_WINDOW_START_SNARQ_Reset
ARQ_TX_NEXT_SN =
ARQ_WINDOW_START_SNARQ_Reset
Discard SDUs corresponding to
ARQ blocks in discard state
Enable Transmission
End ARQ Reset
Figure xxx Transmitter Initiated ARQ Reset
3
IEEE C802.16m-10/0784
ARQ Transmitter
ARQ Receiver
ARQ Reset Type = 0x0
ARQ Reset Type
0x1
Disable Transmission and stop the
running timers
Disable Reception
Initiate ARQ Reset
Disable Reception, stop all
running timers and ARQ
feedback generation
Set
ARQ_WINDOW_START_SNARQ_Reset =
(ARQ_TX_WINDOW_START_SN +
ARQ_WINDOW_SIZE) mod
(ARQ_SN_MODULUS)
Send ARQ Reset Type = 0x0
Send ARQ Reset Type = 0x1, with
Wait for ARQ Reset
Set T22
ARQ_WINDOW_START_SNARQ_Reset
Set T22
ARQ Reset Type = 0x0 or
0x1
Wait for ARQ Reset Type = 0x1
Clear T22
ARQ_RX_WINDOW_START =
Timeout T22
No
Retries
exhausted
Yes
ARQ Reset
Error
ARQ Reset Type = 0x1 or 0x2
ARQ_WINDOW_START_SNARQ_Reset
ARQ_RX_HIGHEST_SN =
Clear T22
ARQ_WINDOW_START_SNARQ_Reset
ARQ_TX_WINDOW_START =
Discard incomplete SDUs
ARQ_WINDOW_START_SNARQ_Reset
Enable reception
ARQ_TX_NEXT_SN =
ARQ_WINDOW_START_SNARQ_Reset
Send ARQ Reset Type = 0x2
Discard SDUs corresponding to
ARQ blocks in discard state
End ARQ Reset
Enable Transmission
End ARQ Reset
Figure yyy Receiver Initiated ARQ Reset
4
Timeout T22
No
Retries
exhausted
Yes
ARQ Reset
Error
IEEE C802.16m-10/0784
[Change 3: Modify the section 16.2.3.45, lines 23-54 as follows]
16.2.3.45 AAI_ARQ-Reset message
The transmitter or receiver may send this message. The message is used in a dialog to reset the parent connection’s ARQ transmitter and receiver state machines. The detail ARQ reset procedure is described in the
section 16.2.13.5.4 <<15.3.8.7.4>>.
Table 741 – AAI_ARQ-Reset message format
Syntax
AAI_ARQ-Reset_Message_Format() {
MAC control Message type = 28
DL/UL indicator
Size (bits)
1
Flow ID
4
Type
2
SN
10
Reserved
17
Note
0b0 = Downlink
0b1 = Uplink
Corresponding connection ID to perform ARQ reset
procedure.
0b00 = Original message from Initiator
0b01 = Acknowledgement from Responder
0b10 = Confirmation from Initiator
0b11 = Reserved
This field shall be included when the ARQ
transmitter sends an ARQ reset message with type
0b00 or 0b01. ARQ transmitter sets this field to
(ARQ_TX_WINDOW_START_SN +
ARQ_WINDOW_SIZE) mod
(ARQ_SN_MODULUS).
Shall be set to zero
}
4 Reference
[1] IEEE P802.16m/D6, “DRAFT Amendment to IEEE Standard for Local and metropolitan area networks Part
16: Air Interface for Broadband Wireless Access Systems”
5