Transcript IEEE C802.16m-09/0189r1

Performance comparison of Constellation Rearrangement and Bit Rearrangement
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE C802.16m-09/0189r1
Date Submitted:
2009-01-05
Source:
Hyungho Park, Sukwoo Lee
LG Electronics, Inc.
Voice: +82-31-450-1934
E-mail:[email protected], [email protected]
Hyungjoon Jeon, Jungnam Yun
POSDATA Co., Ltd.
E-mail:[email protected]
Sung-Eun Park
Samsung Electronics
E-mail:[email protected]
*<http://standards.ieee.org/faqs/affiliationFAQ.html>
Re : IEEE 802.16m-08/052, “Call for Comments on Project 802.16m System Description Document (SDD)”,
Supporting contribution on the comment of SDD section 11.13.2.2
Purpose: To be discussed and adopted by TGm for 802.16m SDD
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HARQ scheme for IEEE 16m
•
16m HARQ schemes with consideration of unequal bit error probability
–
Constellation Rearrangement (CoRe)
•
•
•
In case of high modulation order, modulated symbols consist of component bits with different bit reliability level.
Such a bit reliability difference results in performance degradation in channel decoding.
Constellation Rearrangement is well known scheme which can achieve significant performance gain by
averaging out unequal bit reliabilities.
The performance of CoRe is guaranteed as an additional HARQ gain regardless of MS’s mobility, frequency
channel selectivity and resource allocation type.
HARQ scheme for IEEE 16m
–
Bit Rearrangement (BitRe) using different bit reliability of systematic and parity bits
•
•
•
There exists bit reliability difference between systematic and parity bits.
By mapping systematic bits to MSB (Most Significant Bit) within signal constellation, the reliability of
systematic bits can be improved. However, bit reliability difference between coded bits still remains when chase
LLR combining.
Unequal bit reliability caused by QAM mapping with high modulation order is more important than the different
bit reliability of systematic and parity bits.
HARQ scheme for IEEE 16m
–
Bit Rearrangement (BitRe) to exploit frequency diversity
•
•
•
•
In order to exploit an additional frequency diversity gain, BitRe was proposed to map MSB or LSB to different
carrier which is apart from the previous assigned carrier location.
In case of distributed resource allocation, since frequency diversity gain is already achieved by distributed
resource allocation, it is very unlikely to get an additional gain by BitRe.
In case of localized resource allocation, it is not intended to get frequency selective diversity gain, and it is
hardly achieved due to the low fluctuation of CINR level.
Under the fast fading channel and distributed resource allocation, the BitRe scheme has almost the same
performance gain as a conventional HARQ scheme.
Performance comparison
•
Simulation Parameters
Parameters
Assumption
Bandwidth
10 MHz
Number of subcarrier
1024
Frame length
5ms
Channel estimation
Perfect
Channel code
CTC ½
Modulation
16 QAM
MIMO configuration
Tx: 1, Rx:1 or 2
Resource allocation
PUSC
Channel model
PedB ,VehA
MS mobility
30km/h, 120km/h
Receiver type
Linear MMSE
Maximum number of retransmission
1
Retransmission latency
10ms
Performance Comparison
•
SIMO, PedB 30km/h
PED B, 30km/h, SIMO, 16QAM, 1/2 CTC
PED B, 30km/h, SIMO, 16QAM, 1/2 CTC
1
0.1
0.01
FER
BER
0.1
1E-3
Chase Combing
Bit Rearrangement
CoRe
1
Chase Combing
Bit Rearrangement
CoRe
1E-3
1E-4
0
0.01
2
SNR
3
4
1E-4
0
1
2
3
SNR
4
5
6
Performance Comparison
•
SIMO, VehA 120km/h
VEH A, 120km/h, SIMO, 16 QAM, 1/2 CTC
VEH A, 120km/h, SIMO, 16 QAM, 1/2 CTC
0.1
0.1
FER
BER
0.01
0.01
1E-3
Chase Combing
Bit Rearrangement
CoRe (BER)
Chase Combing
Bit Rearrangement
Constellation Rearrangment
1E-4
1E-3
0
1
3
2
SNR
4
5
0
1
3
2
SNR
4
5
Performance Comparison
•
SISO, VehA 3km/h by LGE
VEH A, 3km/h, SISO, 16 QAM, 1/2 CTC
BER
0.1
0.01
Chase Combing
Bit Rearrangement
Constellation Rearrangment
1E-3
2
3
4
5
6
7
8
9
10
11
SNR
Performance comparison by ITRI
(SISO, VehA 0km/h, C802.16m-08/1144r1)
VEH A, 3km/h, SISO, 16 QAM, 1/2 CTC
[1] in the legend means ZTE BitRe scheme
LGE result shows almost no gain with
BitRe in term of FER performance
though it shows a little bit of gain in
terms of BER performance
FER
0.1
Chase Combing
Bit Rearrangement
Constellation Rearrangment
0.01
2
3
4
5
6
7
SNR
8
9
10
11
Text Proposal for 802.16m SDD
------------------------------------------- Start of the Text ----------------------------------------------
• 11. 13. 2.2. Constellation re-arrangement Bit re-arrangement
Bit re-arrangement (BitRe) is supported in 802.16m. Bit re-arrangement includes a bit-level
interleaver and an inverter. For each transmitted burst, the BitRe-version is selected by the
transmission number of this burst. The specific bit-level interleaver and inverter mechanism is
FFS. Constellation re-arrangement (CoRe) is supported in 802.16m. The CoRe can be
expressed by a bit-level interleaver within a QAM symbol. The specific CoRe version
selection mechanism is FFS.
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