Constellation Rearrangement version indication method
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE C802.16m-09/0343
Date Submitted:
2009-01-07
Source:
Hyungho Park, Sukwoo Lee
LG Electronics, Inc.
LG R&D Complex, 533 Hogye-1dong,
Dongan-gu, Anyang, 431-749, Korea
*<http://standards.ieee.org/faqs/affiliationFAQ.html>
Voice:
+82-31-450-1934
E-mail:hyunghopark@lge.com, sugoo@lge.com
Re : C80216m-08/053r1 “Call for Comments and Contributions on Project 802.16m Amendment Working Document” for the topic of HARQ
Purpose: To provide details on constellation rearrangement version indication method proposed in amendment text of HARQ PHY
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Introduction
•
Constellation Rearrangement (CoRe) is considered as baseline HARQ scheme
in the current IEEE 802.16m SDD text
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•
CoRe is cost-effective solution to enhance HARQ performance with low complexity
CoRe is applied to both Chase HARQ and IR HARQ with 16QAM and 64QAM as modulation
mapping
Key issue points
– CoRe version signaling overhead
•
Bit or symbol / subpacket level
– Incorporation of DL/UL HARQ operation
•
•
Control signaling: Asynchronous DL HARQ
No control signaling: Synchronous UL HARQ
– USCCH misdetection impact
•
In case of USCCH message misdetection, the information on which CoRe version is applied to received
subpacket is also lost. With consideration of USCCH missing, CoRe version indication method should be
considered.
CoRe version indication
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CoRe version indication with consideration of DL/UL HARQ operation
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•
CoRe version indication method should be considered to apply CoRe version to the
corresponding subpacket at every transmission.
In asynchronous DL HARQ, control signaling fields such as SPID, ACID, and AISN are
transmitted for each subpacket by a user specific control channel. Additional control signaling
for CoRe version is needed to avoid USCCH misdetection problem.
In synchronous UL HARQ, no control signaling is needed, and HARQ timing relationship
including ACK/NACK delay and retransmission time should be implicitly known at MS and BS.
Therefore, the transmission order of subpacket is also predetermined with consideration of
CoRe version.
CoRe version indication overhead
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It is recommended that the signaling overhead should be minimized though CoRe shows better
performance if CoRe version is applied in a symbol level.
In case of DL HARQ, it is effective that one CoRe version is signaled for each subpacket.
In case of UL HARQ, it is possible for multiple CoRe versions to be applied to each subpaket in
a symbol level without additional signaling overhead
CoRe version indication in DL HARQ
•
Proposed CoRe version indication
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By considering signaling overhead, CoRe version is signaled for each subpacket to MS as a
starting value for CoRe version.
In case the transmitted bits wraparound at the end of circular buffer, CoRe version is changed
to the next version of current CoRe version
CoRe version indication in UL HARQ
•
Proposed CoRe version indication
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–
In synchronous UL HARQ, MS and BS can know which CoRe versions are applied to each
subpacket.
Without any additional signaling for CoRe version, BS is able to decode the subpacket symbols
rearranged by CoRe because of implicit CoRe version mapping. Therefore, the corresponding
CoRe version can be applied to each symbol within subpacket.