Transcript Slides S802.16m-09/1221

SDD Comments on PHY Segmentation for Multicarrier Operation
Document Number: Slides S80216m-09/xxxx
Date Submitted: 2009-6-7
Source:
Lei Huang
Panasonic Singapore Laboratories Email: [email protected]
Isamu Yoshii, Kenichi Kuri
Panasonic Corporation
Email: [email protected]
Venue:
IEEE Session #62, San Francisco, USA.
Re: Category: SDD comments - Chapter 17.3 (PHY Aspects of OFDMA Multi-carrier Operation)
Base Contribution: C90216m-09/xxxx
N/A
Purpose:
For TGm discussion and adoption of 802.16m SDD text.
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1
Background
• According to 16m AWD, for CC-HARQ (re)transmissions and initial transmission of IR-HARQ, the
modulated symbol sequence actually consists of two parts: systematic part and parity part.
• According to 16m SDD, the modulated symbol sequence may be transmitted on DRUs across several
RF carriers, via PHY segmentation and mapping to different RF carriers, by using the same MCS and
MIMO scheme.
Systematic bits
CTC encoding
Parity bits
A subblock
B subblock
Y1 subblock
Y2 subblock
W2 subblock
W1 subblock
Subblock
interleaver
Subblock
interleaver
Subblock
interleaver
Subblock
interleaver
Subblock
interleaver
Subblock
interleaver
Bit grouping
Circularly leftshift k bits
Circularly left-shift 1 bit
Bit selection for
initial transmission
Systematic bits
Parity bits
Modulated symbol
sequence
Systematic part
Circularly left-shift k bits
When the FEC block size
NFB is equal to multiple of
the modulation order, k =
1. Otherwise, k = 0
Parity part
2
Simple PHY Segmentation Scheme
• Simple scheme: The modulated symbol sequence is sequentially segmented into N
blocks, each having P symbols, where P is number of effective data subcarriers per
LRU, and N is total number of allocated LRUs.
• Problem: Both systematic and parity bits are transmitted only over a portion of
active carriers, thus frequency diversity for systematic and parity bits is not fully
exploited. This may degrade CTC decoding performance, especially in higher
coding rate cases.
Parity part
Systematic part
Modulated
symbol sequence
Block 1
Block 2
Block Index
Block 3
Segmentation
Symbol index
Carrier Carrier Carrier
1
2
0
Logical carrier index
* Carrier 0 is
primary carrier
LRU index
Block 1
Block 2
Block 3
A( 1 ) A( 2 ) A( 3 ) A( 4 )
B(10)B(11)B(12)B(13)
Y 2 (9)Y 1 (10)Y 2 (10)Y 1 (11)
A( 5 ) A( 6 ) A( 7 ) A( 8 )
B(14 )B(15)B(16)B(17)
Y 2 (11)Y 1 (12)Y 2 (12)Y 1 (13)
A( 9 ) A( 1 0 ) A( 1 1 ) A( 1 2 )
B(18 )B(19)B(20)B(21)
Y 2 (13)Y 1 (14)Y 2 (14)Y 1 (15)
A(13)A(14)A(15)A(16)
B(22)B(23)B(24)B(1)
Y 2 (15)Y 1 (16)Y 2 (16)Y 1 (17)
A(17)A(18)A(19)A(20)
Y2(1)Y1(2)Y2(2)Y1(3)
Y 2 (17)Y 1 (18)Y 2 (18)Y 1 (19)
A(21)A(22)A(23)A(24)
Y2(3)Y1(4)Y2(4)Y1(5)
Y 2 (19)Y 1 (20)Y 2 (20)Y 1 (21)
B(2) B(3) B(4) B(5)
Y2(5)Y1(6)Y2(6)Y1(7)
Y 2 (21)Y 1 (22)Y 2 (22)Y 1 (23)
B(6) B(7) B(8) B(9)
Y2(7)Y1(8)Y2(8)Y1(9)
Y 2 (23)Y 1 (24)Y 2 (24)Y 1 (1)
Example: NFB= 48, 16 QAM, R = ½, P = 8
3
Permutation Scheme
• Permutation scheme: Block interleaving is applied to the modulated symbol
sequence
– Block interleaver size is P × N, where P is number of effective data
subcarriers per LRU, and N is total number of allocated LRUs
– Modulated symbol sequence is written into the block interleaver in row-byrow, and read out in column by column
• Benefit: Frequency diversity for systematic/parity bits are improved since
systematic/parity bits are almost equally allocated to each block/LRU
Parity part
Systematic part
Modulated symbol
sequence
Block 1
Block 2
Block Index
Block 3
Block interleaving
and segmentation
Symbol index
LRU index
Carrier
Carrier
Carrier
0
1
2
Logical RF carrier
index
* Carrier 0 is
primary carrier
Block 1
Block 2
Block 3
A(1)A(2)A(3)A(4)
A(5)A(6)A(7)A(8)
A(9)A(10)A(11)A(12)
A(13)A(14)A(15)A(16)
A(17)A(18)A(19)A(20)
A(21)A(22)A(23)A(24)
B(2)B(3)B(4)B(5)
B(6)B(7)B(8)B(9)
B(10)B(11)B(12)B(13)
B(14)B(15)B(16)B(17)
B(18)B(19)B(20)B(21)
B(22)B(23)B(24) B(1)
Y2(1)Y1(2)Y2(2) Y1(3)
Y2(3)Y1(4)Y2(4) Y1(5)
Y2(5)Y1(6)Y2(6) Y1(7)
Y2(7)Y1(8)Y2(8) Y1(9)
Y 2 (9)Y 1 (10)Y 2 (10) Y 1 (11)
Y 2 (11)Y 1 (12)Y2 (12) Y 1(13)
Y 2 (13)Y 1 (14)Y2 (14) Y 1(15)
Y 2 (15)Y 1 (16)Y2 (16) Y 1(17)
Y 2 (17)Y 1 (18)Y2 (18) Y 1(19)
Y 2 (19)Y 1 (20)Y2 (20) Y 1(21)
Y 2 (21)Y 1 (22)Y2 (22) Y 1(23)
Y 2 (23)Y 1 (24)Y 2 (24) Y 1 (1)
Example: NFB= 48, 16 QAM, R = ½, P = 8
4
Conclusion
• Before PHY segmentation, a symbol permutation shall be applied to the
modulated symbol sequence for the purpose of improving frequency diversity
for OFDMA multicarrier operation. The detailed permutation scheme is TBD.
Same as single
carrier operation
Burst CRC
encoder
Data
randomizer
Burst
partition
FEC block
CRC
encoder
FEC
encoder
Especially for multicarrier operation
with PHY segmentation
Bit selection
& repetition
Collection
Modulation
Symbol
permutation
Segmentation
over multiple
carriers
Channel coding procedure for multicarrier operation with PHY segmentation
5