Transcript IEEE C802.16m-09/1261r2

Proposed Improvement on PA Uplink Error Handling
Document Number:
Date Submitted:
Source:
Lu Zhaohua , Sun Bo
ZTE Corporation
Hujun Yin
Intel Corporation
IEEE C80216m-09/1261
2009-7-6
E-mail:
{ lu.zhaohua, sun.bo1}@zte.com.cn
[email protected]
*http://standards.ieee.org/faqs/affiliationFAQ.html
Venue:
RE:
IEEE 802.16m Session #62
Category: AWD comments / Area: Chapter 15.2.7 (Persistent scheduling)
“Comments on AWD 15.2.7 Persistent scheduling”
Base Contribution:
Purpose:
For discussion and adoption in the 802.16m AWD 802.16m-09/0010r2
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Error Handling in Current PA MAC Procedure
Problem
• Current error handling scheme is reasonable for DL persistent
resource allocation because:
– AMS shall feedback ACK/NACK or nothing on HARQ channel to the
first PA sub-packet. Thus
– ABS shall understand if AMS has successfully decoded the PA-AMAP
or not.
• For UL persistent resource allocation, it is another story:
– HFA is defined as a downlink HARQ feedback channel, so
– ABS cannot identify if AMS has failed to decode PA A-MAP thus
cannot transmit data using assigned LRU resources. Then
– ABS will trigger the HARQ process and until the HARQ process failed
it re-arrange PA resource for AMS. And
– This process will waste resources unnecessarily.
16e Solution
•
A MAP HARQ Feedback channel is allocated as well for AMS to feedback if the PA MAP
information is successfully decoded.
•
Problem
PA-MAP
MAP
HARQ
DL
UL
...
DL
UL
PA
PA(Wasted)
Frame k
Frame
(k+N*AP)
– In above case, the ABS sends PA MAP to assign UL persistent resource and MAP
HARQ feedback channel to an AMS, but the AMS fails to receive PA MAP, so
persistent resource in frame k assigned to the AMS is wasted.
•
Improvement
– In order to solve above problem, the AMS shall begin to transmit uplink data on UL
persistent resource after the frame which the AMS send ‘ACK’ through MAP HARQ
feedback channel to the ABS. In another words, the persistent resource in frame k can
be temporarily scheduled to other AMSs by the ABS.
Proposed Solution
• Proposed Solution:
– UL Persistent A-MAP IE should carry ‘MAP HARQ
Feedback channel Allocation’ field for AMS to feedback if
the UL PA MAP information is successfully decoded.
– When the ABS allocate a UL PA resource, it shall allocate a
corresponding MAP HARQ Feedback channel as well. And
the allocation of UL PA resource shall be delayed to the
corresponding MAP HARQ Feedback channel so that the
ABS can have chance to detect if the UL PA MAP
information is successfully decoded.
– If the ABS get nothing on the MAP HARQ Feedback
channel, neither ACK nor NACK, the ABS can transmit the
same UL Persistent A-MAP IE again.
Proposed AWD Text
•
===============Text Start========================
•
•
15.2.7.4 Error Handling Procedure
15.2.7.4.1 Error Handling Procedure for an Individual Connection
•
•
[Delete the red characters and add the blue characters in following paragraph]
For transmissions with HARQ enabled, an ACK is transmitted to acknowledge the
successful decoding of a data burst, or a NACK is transmitted to notify failure in
decoding a burst transmitted on the DL/UL. If an ACK or a NACK for the initial
data burst identified by the DL/UL Individual Persistent A-MAP IE is detected in
the assigned HARQ Feedback channel, the ABS shall assume that the DL/UL
Individual Persistent A-MAP IE is correctly received. If the initial data burst
identified by the UL Individual Persistent A-MAP IE is successfully decoded in
HARQ period, the ABS shall assume that the UL Individual Persistent A-MAP IE is
correctly received.
In the absence (When NULL detection) is used, in the absence of an ACK or a
NACK in the HARQ feedback channel assigned in the DL/UL Individual Persistent
A-MAP IE for the data burst, the ABS shall assume that the AMS has not received
the DL/UL Individual Persistent A-MAP IE and the same DL/UL Persistent A-MAP
IE can be transmitted again.
•
Proposed AWD Text (Contd.)
•
15.2.7.4.2 Error Handling Procedure for an Multiple Connection
•
•
[Delete the red characters and add the blue characters in following paragraph]
For transmissions with HARQ enabled, an ACK is transmitted to acknowledge the
successful decoding of a data burst, or a NACK is transmitted to notify failure in
decoding a burst transmitted on the DL/UL. If an ACK or a NACK for all the initial
data bursts identified by the DL/UL Composite Persistent A-MAP IE is detected in
the assigned HARQ Feedback channel, the ABS shall assume that the DL/UL
Composite Persistent A-MAP IE is correctly received by all the connections. If one
of the initial data burst identified by the UL Composite Persistent A-MAP IE is
successfully decoded in HARQ period, the ABS shall assume that the UL
Composite Persistent A-MAP IE is correctly received by that connections.
In the absence (When NULL detection)is used, in the absence of an ACK or a
NACK in the HARQ feedback channel assigned to one or more connections in the
DL/UL Composite Persistent A-MAP IE for data burst, the ABS shall assume that
the corresponding AMSs have not received the DL/UL Composite Persistent AMAP IE and the DL/UL Composite A-MAP IE can be transmitted again for these
connections. If the persistent allocation needs to be transmitted to only one
connection the DL/UL Individual A-MAP IE can be transmitted again for this
connection.
•
•
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