Evaluation of DL subchannelization
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE C802.16m-09/0347
Date Submitted:
2009-01-07
Source:
Taeyoung Kim, Hyunkyu Yu, Jaeweon Cho,
Hokyu Choi , Heewon Kang
Voice:
E-mail:
+82-31-279-0202
ty33.kim@samsung.com
Samsung Electronics Co., Ltd.
416 Maetan-3, Suwon, 443-770, Korea
Venue:
IEEE 802.16m Session#59, San Diego, US
IEEE 802.16m-08/053r1, “Call for Comments and Contributions on Project 802.16m Amendment Working Document”.
Target topic: “DL Physical Structure”
Base Contribution:
None
Purpose:
Discussion and Approval
Notice:
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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
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Motivation
• In the current IEEE 802.16m Amendment Working Document
(IEEE80216m-08/050),
– The detail permutation rules (e.g. subband partitioning, miniband permutation,
secondary permutation, subcarrier permutation) are NOT determined yet.
• In the document C80216m-08_1508 or the latest version, there are
several permutation rules proposed from many companies
• This contribution shows the several kinds of evaluation results to
compare the permutation rules proposed from many companies
2/14
Performance Metric
• Emulation for estimating freq. diversity gain effect
– Compare the number of subcarriers located in the different frequency
band according to the different number of DRUs
• Link level simulation
– Single cell environment
– To see the frequency diversity gain
• Hitting ratio comparison
– To verify the interference due to the tone-pair hits from different
cells/sectors
3/14
Emulation for freq. diversity
• Frequency diversity gain is related with how many subcarriers
having different channel statistics exist within data burst
• Performance Metric
– Number of subcarriers located in the different frequency band
• Evaluation results
4/14
Link level simulation (1)
• Simulation Conditions
– Working Scenarios
Freq. Partition
# of subbands
# of minibands
# of PRUs in FPi
FP0
2
4
12
FP1 ~ FP3
2
4
12
FP0
4
8
24
FP1 ~ FP3
0
8
8
FP0
6
24
48
FP1 ~ FP3
0
0
0
Scenario #1
Scenario #2
Scenario #3
– Single-cell Environment
– MIMO configuration
• 2x2 SFBC
• Uncorrelated MIMO (4 lambda wavelength)
– Channel: PedA, PedB
– Channel estimator: 2D MMSE CH. Est.
Link level simulation (2)
Working scenario #2
• Evaluation Results
Single cell Environment
0
10
Samsung
Intel
LGE
– FER vs. SNR
• PedA, 3km/h
-1
10
FER
• # of LRUs = 1
– Cell_ID = 0
-2
10
Working scenario #1
Single cell Environment
0
-3
10
10
Samsung
Intel
LGE
-6
-4
-2
0
2
4
SNR[dB]
6
8
10
12
Working scenario #3
Single cell Environment
0
10
-1
10
FER
Samsung
Intel
LGE
-1
10
-2
FER
10
-2
10
-3
10
-6
-4
-2
0
2
4
SNR[dB]
6
8
10
12
-3
10
-6
-4
-2
0
2
4
SNR[dB]
6
8
10
12
Link level simulation (3)
Working scenario #2
• Evaluation Results
Single cell Environment
0
10
Samsung
Intel
LGE
– FER vs. SNR
• PedB, 3km/h
-1
10
FER
• # of LRUs = 1
– Cell_ID = 0
-2
10
Working scenario #1
Single cell Environment
0
-3
10
10
Samsung
Intel
LGE
-4
-2
0
2
4
SNR[dB]
6
8
10
Working scenario #3
Single cell Environment
0
10
-1
10
FER
Samsung
Intel
LGE
-1
10
-2
FER
10
-2
10
-3
10
-4
-2
0
2
4
SNR[dB]
6
8
10
-3
10
-4
-2
0
2
4
SNR[dB]
6
8
10
Conclusion – LLS results
• For LGE’s proposal, the frequency diversity order can be
different according to different Cell_ID, so the LLS
performance can be different.
• In terms of frequency diversity gain from LLS results,
proposal from Intel and Samsung have the best
performance compared to LGE’s proposal.
Hitting Ratio Comparison (1)
• Evaluate the number of hits among different Cell_IDs for
subcarrier permutation
• Evaluation methodology
– To choose (512, 2)=130816 cell pairs
– For each cell pair, there are NDRU*NDRU sub-channel pairs,
• Number of hits : the number of same tone-pairs for each LRU pair
• Average Hit Number : Hit statistic over (130816*NDRU*NDRU)
Hitting Ratio Comparison (2)
• Results
– k : number of tone-pairs hit within one LRU
# of
DRUs
4
8
12
24
Avg. hitting
No.
Hitting ratio
(k: 32~48)
Hitting ratio
(k: 24~48)
Hitting ratio
(k: 0~8)
Hitting ratio
(k: 0~12)
Samsung
12
4.86%
28.92%
38.65%
71.08%
Intel
12
6.21%
31.26%
43.69%
68.74%
LGE
11.92
1.31%
3.14%
14.25%
66.91%
Samsung
6
0.59%
3.06%
73.77%
90.82%
Intel
6
1.54%
1.54%
60.89%
92.20%
LGE
5.99
0.04%
0.19%
90.64%
98.71%
Samsung
4
0.18%
0.63%
84.67%
93.96%
Intel
4
0.7%
1.05%
80.78%
90.81%
LGE
3.99
0.01%
0.05%
98.06%
99.6%
Samsung
2
0.02%
0.09%
97.13%
99.11%
Intel
2
0.19%
0.19%
94.16%
98.59%
LGE
1.99
0.00%
0.01%
99.78%
99.96%
Conclusion – Hitting Ratio
• For average hit number, the proposal from Intel,
Samsung and LGE have almost same number.
• For Intel’s proposal, the probability to collide all tonepairs is higher than LGE and Samsung
• LGE’s subcarrier permutations have the best
performance compared to Intel and Samsung in terms of
Hitting Ratio
Recommendation
• Discuss and adopt the formulas proposed by
Samsung in IEEE C802.16m-08/1508r1