Transcript IEEE C802.16m-09/0622

Evaluation and Proposed Text on DL Subcarrier Permutation
Document Number:
IEEE C80216m-09_0622
Date Submitted:
2009-03-02
Source:
HanGyu Cho, Seunghyun Kang, Jong Young Han, Sunam Kim,
Email: {hgcho, sh_kang
Jin Sam Kwak
fanaticey, snkim86, samji} @lge.com
LG Electronics
Venue:
“802.16m AWD”: IEEE 802.16m-09/0012. ”Call for Contribution on Project 802.16m Amendment
Working Document (AWD) Content” Target topic: Call for Comments on Amendment Working
Document
Purpose:
To provide proposed text on DL subcarrier permutation to be approved by TGm and adopted in the
Amendment Working Document
Notice:
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
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Motivation



In the current IEEE 802.16m Amendment Working
Document (IEEE 802.16m-09/0010), the DL subcarrier
permutation formula in the section 15.3.5.3.3 is TBD
So far, there have been many subcarrier permutation
formulas proposed by each company
This contribution reviews those rules and suggests a DL
subcarrier permutation formula based on simulation
results.
Evaluation Criteria for Subcarrier Permutation

Link level simulation


To show the diversity gain for distributed LRU
Hit ratio

To check the interference averaging effect of distributed
LRU
Subcarrier Permutation Formulas Considered

LGE’s proposed formula (updated)
k  {LDRU , FPi  f (m, s )  g ( PermSeq(), s, m, l , t )  l  LSP,l } mod{ LSP,l  LDRU , FPi }
where
f (m, s )  (5m  7 s ) mod LSP,l
g ( PermSeq(), s, m, l , t )  PermSeq(( f (m, s)  s  OSP  l  t ) mod LDRU ,FPi )
where
 GCD( LDRU , FPi, DSP ) 
PermSeq(i )  {DSP  i  OSP  i 
} mod LDRU , FPi,
LDRU , FPi


where
DSP  (Cell ID mod( LDRU , FPi 1))  1
 Cell ID 
OSP  
 1
(
L

1
)
 DRU , FPi

i  0,1, , LDRU , FPi  1
Subcarrier Permutation Formulas Considered

LGE’s old formula (C802.16m-09/0318r1) – for
comparison
k  LDRU , FPi  f (m, s)  g ( PermSeq(), s, m, l , t )
where
f (m, s )  (5m  7 s ) mod L pair,l
g ( PermSeq(), s, m, l , t )  PermSeq(( f (m, s )  s  OIP  l ) mod LDRU ,FPi )
where
 GCD( LDRU ,FPi, DIP ) 
PermSeq(i )  {DIP  i  OIP  i 
} mod LDRU ,FPi,
L
DRU , FPi


where
DIP  (Cell ID mod( LDRU ,FPi  1))  1
 Cell ID 
OIP  
 1
 ( LDRU , FPi  1) 
i  0,1,  , LDRU ,FPi  1
Subcarrier Permutation Formulas Considered

Intel (C802.16m-08/1508r1)
k  LDRU , FPi  f (m, s)  g ( PermSeq(), s, m, l , t )
where
f ( m, s )  {m  13s} mod L pair,l


g ( PermSeq, s, m, l , t )  {PermSeq({ f (m, s)  s  t  l} mod LDRU ,FPi )}  DL _ PermBase mod LDRU ,FPi

PermSeq is the sequence of length LDRU, FPi specified in Table
15.3.5.1 (Refer to C802.16m-08/1508r1).
Subcarrier Permutation Formulas Considered

Samsung (C802.16m-08/1508r1)
k  LDRU , FPi  f (m, s)  g ( PermSeq(), s, m, l , t )
where
f (m, s)   m  13  s  mod L pair ,l
g ( PermSeq, s, m, l , t )  PermSeq  f  m, s   107  l  s  mod LDRU , FPi 

PermSeq is the sequence of length LDRU, FPi and is determined
by SEED = {(IDcell+1024*t)*1357351} mod 220 and the
permutation sequence generation algorithm specified in
C80216m-08_1508r1
Subcarrier Permutation Formulas Considered

NSN



ZTE, ITRI


C802.16m-08/1508r1
NSN’s performance is not shown here due to difficulty in
simulation of two-step subcarier permutation (please refer to
C802.16m-08/0260r2 )
…
Motorola

No proposal
Simulation Environment: LLS (1/2)

BW=10MHz (NPRU=48) – Copied from Intel’s contribution (IEEE
802.16m-09/0251 )
Scenario1 (Mixed Reuse 1&3 – equal size)
# of subbands
(KSB,FP,i)
# of minibands
(KMB,FPi)
# of PRUs in
FPi
FP1
2
4
12
FP2
2
4
FP3
2
FP4
2
Freq.
Partition
Scenario 3 (Reuse 1)
# of subbands
(KSB,FP,i)
# of minibands
(KMB,FPi)
# of PRUs in
FPi
FP1
6
24
48
12
FP2
0
0
0
4
12
FP3
0
0
0
4
12
FP4
0
0
0
# of subbands
(KSB,FP,i)
# of minibands
(KMB,FPi)
# of PRUs in
FPi
Scenario 2 (Mixed Reuse 1&3 – unequal size)
Freq.
Partition
Scenario 4 (Reuse 3)
# of subbands
(KSB,FP,i)
# of minibands
(KMB,FPi)
# of PRUs in
FPi
FP1
4
8
24
FP1
0
0
0
FP2
0
8
8
FP2
2
8
16
FP3
0
8
8
FP3
2
8
16
FP4
0
8
8
FP4
2
8
16
Freq.
Partition
Freq.
Partition
Simulation Environment: LLS (2/2)


MIMO mode SFBC
Antenna configuration



Channel


10MHz
Fixed AMC


PedB 3Km/h
System BW


2 Tx antennas with zero correlation (4 wavelengths)
2 Rx antennas
QPSK ½
Averaged over Cell ID 0~47
Simulation Results: LLS
Scenario 1
0
10
-1
10
FER

-2
10
Intel
Samsung
LGE
-3
10
-3
-2
-1
0
1
SNR (dB)
2
3
4
Simulation Results: LLS
Scenario 2
0
10
-1
10
FER

-2
10
Intel
Samsung
LGE
-3
10
-3
-2
-1
0
1
SNR (dB)
2
3
4
Simulation Results: LLS
Scenario 3
0
10
-1
10
FER

-2
10
Intel
Samsung
LGE
-3
10
-3
-2
-1
0
1
SNR(dB)
2
3
4
Simulation Results: LLS
Scenario 4
0
10
-1
10
FER

-2
10
Intel
Samsung
LGE
-3
10
-3
-2
-1
0
1
SNR (dB)
2
3
4
Simulation Results: modified LLS
There are two cells: Home cell and Interfering cell


50% partial loading
Home cell


Scenario 3 (6 SBs and 24 MBs) with cell ID=0
Interfering cell

4 SBs and 32 MBs with cell ID=18
0
10
-1
10
FER

-2
10
Intel
Samsung
LGE
-3
10
-3
-2
-1
0
1
SNR (dB)
2
3
4
Conclusion on LLS results


We evaluated DL subcarrier permutations with
varying scenarios.
In terms of diversity gain, LGE, Intel, SS have the
similar performance in all cases
Simulation Environment: Hit ratio


BW
10MHz
#Cell ID
512
Distributed LRU
48 subcarrier-pairs (excluding pilot
subcarriers for 2Tx streams)
NDRU
varying
For choose(512,2)=130816 cell pairs,
For each cell pair, there are NDRU * NDRU sub-channel pairs,
 Hit Number: the number of same subcarrier-pairs for each su
b-channel pair
 Average Hit Number: hit statistic over 130816 cell pairs
 % of total hits: (Average Hit Number) / (NDRU * NDRU) * 100%
Simulation Results: Hit ratio
# of Hits (k)
#. of DRUs
4
8
12
24
48
k≥12
k≥24
k≥36
LGE (old)
61.87 %
14.55
2.04
LGE (updated)
61.87
14.55
2.04
Intel
56.31
31.26
6.21
Samsung
61.15
27.89
5.48
LGE (old)
9.67
1.16
0.20
LGE (updated)
9.67
1.16
0.20
Intel
39.11
1.54
1.54
Samsung
26.12
3.38
0.61
LGE (old)
1.36
0.22
0.05
LGE (updated)
1.36
0.22
0.05
Intel
10.88
1.03
0.68
Samsung
6.48
0.24
0.06
LGE (old)
0.27
0.02
0.000064
LGE (updated)
0.27
0.02
0.000064
Intel
2.28
0.17
0.165882
Samsung
0.51
0.03
0.005034
LGE (old)
0.04
0.005
0
LGE (updated)
0.04
0.005
0
Intel
0.72
0.039
0.039496
Samsung
0.10
0.004
0.000434
Best cases were colored
Conclusion on Hit ratio results

In terms of hitting ratio, LGE has the best
performance showing the smallest ‘larger hit ratios’ in
most
Conclusions



In terms of diversity gain, LGE, Intel, SS have the
similar performance in all cases
In terms of hitting ratio, LGE has the best
performance showing the smallest ‘larger hit ratio’ in
most cases
In terms of complexity, LGE is most simplest


Intel requires a huge table
SS requires a complex algorithm for sequence generation
Text Proposal


Replace the equation k  LDRU , FPi  f (m, s)  g ( PermSeq(), s, m, l , t )
in (186) of page 31 of IEEE 802.16m-09/0010 by the
subcarrier permutation formula in the page 4 of this
contribution
Delete the following text in line 35 to 37 of page 31 of
IEEE 802.16m-09/0010
“PermSeq() is the permutation sequence generated
by a function or by a lookup table;
g(PermSeq(),s,m,l,t) is a function (TBD) with value
from the set [0, LDRU,FPi - 1]; f(m,s) is a function (TBD)
with value from the set [0, LSP,l - 1].”