IEEE 802.15-10-0501-00-004g
Submission Sangsung Choi & Cheolho Shin, ETRI
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: A proposal of Comment resolutions for Interleaver and Pad bits in OFDM Group.
Date Submitted: July, 2010
Source: Sangsung Choi & Cheolho Shin
Electronics and Telecommunications Research Institute(ETRI)
Voice: +82 42 860 6722, +82 42 860 6831 Fax: +82 42 860 5218
E-maill: [email protected], [email protected]
Re: TG4g comment resolution
Abstract: Working doc of OFDM Comment Resolutions
Purpose: Comment Resolutions for CID #1041, #1409,#1411 and #1064
Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.
Slide 1
July, 2010
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Comment resolutions for CID #1041, #1409 and #1411
Slide 2
• Comments - CID #1041 : modify the Ncbps clearly - CID #1409 : Definition of Ncbps and Nbpsc are needed - CID #1411 : Definition of Ncbps and Nbpsc are needed
• Proposed Change - CID #1041 : for example, Ncbps = 96*{1,2} -> Ncbps = 96*Nbpsc - CID #1409 : Definition of Ncbps and Nbpsc are needed - CID #1411 : Provide the definitions
• Proposed Resolution - CID #1041 : proposed to modify accordingly. See also Document 15-10-0423-00-004g
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Comment resolutions for CID #1041, #1409 and #1411
Slide 3
Nrow = 12;OFDM Option 1: Ncbps = 96 *NbpscOFDM Option 2: Ncbps = 48 *NbpscOFDM Option 3: Ncbps = 24 *NbpscOFDM Option 4: Ncbps = 12 *NbpscOFDM Option 5: Ncbps = 6 *Nbpsc
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Comment resolutions for CID #1041, #1409 and #1411
Slide 4
• For example , in MCS 0 of OFDM Option 1 - Nbpsc = 1 (BPSK) , Ncbps = 96 * 1 = 96 - Interleaving size = 96• For example , in MCS 0 of OFDM Option 2 - Nbpsc = 1 (BPSK) , Ncbps = 48 * 1 = 48 - Interleaving size = 48• For example , in MCS 1 of OFDM Option 3 - Nbpsc = 1 (BPSK) , Ncbps = 24 * 1 = 24 - Interleaving size = 24• For example , in MCS 2 of OFDM Option 4 - Nbpsc = 2 (QPSK) , Ncbps = 12 * 2 = 24 - Interleaving size = 24• For example , in MCS 6 of OFDM Option 5 - Nbpsc = 2 (QPSK) , Ncbps = 6 * 2 = 12 - Interleaving size = 12
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Comment resolutions for CID #1064
Slide 5
• Comments - CID #1064 : OPFM symbol number for the PHY header of Option 1
and Option 2 should be modified considering the interleaver size
• Proposed Change - CID #1064 : 4 OFDM symbols for the PHY header of Option 1 and 8 OFDM symbols for the PHY header of Option 2
• Proposed Resolution - CID #1064 : Proposed resolution in document 15-10-0423-00-004g.
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
PHY Header fields for OFDM
Slide 6
• PHY Header fields are 36 bits including HCS and tail bits
Rate(5 bits)
Reserved(1 bit)
Frame Length(11 bits)
Reserved(2 bits)
Scrambler(2 bits)
Reserved(1 bit)
6 bits 2 bytes
Header Check SequenceCalculation
Append HCS
HCS
Rate(5 bits)
Reserved(1 bit)
Frame Length(11 bits)
Reserved(2 bits)
Scrambler(2 bits)
Reserved(1 bit)
6 bits 2 bytes 1 byte
HCS(8 bits)
Tail(6 bits)
6 Zero Bits
Pad bits
Append PAD bits
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Construction of Symbol number and Pad bits
Slide 7
• The Symbol number and Pad bits can be constructed by the formulas (16), (17) and (18) in page 67 of draft standard.
• According to these formulas, the PHY header occupies 3 OFDM symbols for OFDM 1 and 6 OFDM symbols for Options 2,3,4 and 5.
• However, these formulas should be corrected considering the Interleaving size and FDS repetition because the Interleaving can’t be completed in several data rate modes using FDS if we use these formulas.
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 8
- According to Formula (16), (17), and (18)
• Nsym=Ceiling((8xLENGTH+6)/NDBPS)
Nsym = ceiling(8x3.75+6)/12)=3
• NDATA=Nsym x NDBPS
MDATA=3 x 12 =36
• Npad=NDATA-(8XLENGTH+6),
Npad = 36-(8 X 3.75+6) = 0
For Example of Option 1
Optiondata rate
(Kbps)Modulation
Coding
rate
(R)
FDS
(NF)
Coded Bits
/OFDM symbol
at IFFT
NCBPS
DATA Bits
/OFDM symbol
at IFFT
NDBPS
NPAD NSYM
100 BPSK 0.5 4 24 12 0 3
50 BPSK 0.5 4 12 6 0 6
50 BPSK 0.5 2 12 6 0 6
50 QPSK 0.5 2 12 6 0 6
50 DCM 0.75 1 8 6 0 65
1
2
3
4
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 9
For Example of Option 1(Continued)
DATAEncoder
(R=½)Interleaver
SubcarrierModulation
Mapper
FDS ( X4 )
IFFTCyclicPrefix
InsertionFiltering
DAC/RF Transceiver
/PA
Pad : 0 bits
Header : 36 bits
36 bits 72 bits 72 bits
72 carriers
24 carriers/OFDM
symbol
3 OFDM symbols
Interleaver size = 96
- According to the formula in page 67 of draft standard,
The bit number of PHY header fields is 36, and then it increases 72 bits
after Convolutional encoder.
<Block diagram of PHY Header Construction>
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 10
1 2 3 4 5 6 7 8 910
11
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# 1 # 2 # 9
# 1 # 2 # 8
89
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96
# 12
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# 11
73
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# 10
For Example of Option 1(Continued)
- In this case, the interleaving size is 96 .
- Thus, the interleaving of 96 can't be completed using 72 bits of PHY
header fields as shown below figure .
<Interleaving Procedure>
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 11
- According to Formula (16), (17), and (18)
• Nsym=Ceiling((8xLENGTH+6)/NDBPS)
Nsym = ceiling(8x3.75+6)/6)=6
• NDATA=Nsym x NDBPS
MDATA=6 x 6 =36
• Npad=NDATA-(8XLENGTH+6),
Npad = 36-(8 X 3.75+6) = 0
For Example of Option 2
Optiondata rate
(Kbps)Modulation
Coding
rate
(R)
FDS
(NF)
Coded Bits
/OFDM symbol
at IFFT
NCBPS
DATA Bits
/OFDM symbol
at IFFT
NDBPS
NPAD NSYM
100 BPSK 0.5 4 24 12 0 3
50 BPSK 0.5 4 12 6 0 6
50 BPSK 0.5 2 12 6 0 6
50 QPSK 0.5 2 12 6 0 6
50 DCM 0.75 1 8 6 0 65
1
2
3
4
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 12
For Example of Option 2(Continued)
- According to the formulas in page 67 of draft standard,
The bit number of PHY header fields is 36, and then it increases 72 bits
after Convolutional encoder.
<Block diagram of PHY Header Construction>
DATAEncoder
(R=½)Interleaver
SubcarrierModulation
Mapper
FDS ( X4 )
IFFTCyclicPrefix
InsertionFiltering
DAC/RF Transceiver
/PA
Pad : 0 bits
Header : 36 bits
36 bits 72 bits 72 bits
72 carriers
12 carriers/OFDM
symbol
6 OFDM symbols
Interleaver size = 48
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 13
For Example of Option 2(Continued)
- In this case, the interleaving size is 48 .
- Thus, the interleaving of 48 can't be completed using 72 bits of PHY
header fields as shown below figure .
1 2 3 4
1 5 913
17
21
25
29
33
37
41
45
4 812
16
20
24
28
32
36
40
44
48
# 1 # 2 # 12
# 1 # 4
5 6 7 845
46
47
48
# 11
41
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# 13 # 18 # 24
# 5 # 8
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# 23
89
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# 19
73
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76
<Interleaving Procedure>
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
PSDU fields for OFDM
Slide 14
• The maximum PSDU are 2047bytes
• For convenience of explanation, PSDU Length of 3 bytes is assumed.
• Although the formulas in page 67 of draft standard generate the Symbol number and Pad bits in PHY Header fields correctly, the Interleaving still can’t be completed in several data rate modes Using FDS of Option3 and 4.
PSDU : 3 Bytes Tail bits Pad bits
6 Zero Bits(Tail Bits)
Pad Bits
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 15
- If the PSDU Length of 3bytes is assumed in 50Kbps mode of Option 3
and 4, the number of Symbol and Pads bits can be calculated by the
formula (16), (17), and (18) in page 67 of draft standard.
• Nsym = Ceiling((8xLENGTH+6)/NDBPS)
Nsym = ceiling(8x3+6)/6)=5
• NDATA = Nsym x NDBPS
MDATA=5 x 6 =30
• Npad = NDATA-(8XLENGTH+6),
Npad = 30-(8 X 3+6) = 0
For Example of Option 3 & 4
Optiondata rate
(Kbps)Modulation
Coding
rate
(R)
FDS
(NF)
Coded Bits
/OFDM symbol
at IFFT
NCBPS
DATA Bits
/OFDM symbol
at IFFT
NDBPS
NPAD NSYM
50 BPSK 0.5 2 12 6 0 5
50 QPSK 0.5 2 12 6 0 5
3
4
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 16
- PHY Payload of 30 bits including PSDU and tail bits increase (3*8 + 6)*2 = 60 bits after Convolutional encoder.
<Block diagram of PSDU Construction>
For Example of Option 3 & 4(Continued)
DATA ScramblerEncoder
(R=½)Puncturer Interleaver
SubcarrierModulation
Mapper
FDS ( X2 )
IFFTCyclicPrefix
InsertionFiltering
DAC/RF Transceiver
/PA
If R=1/2
PSDU 3byte + tail bits
3*8+6 = 30 bits Pad : 0 bits
30 bits 60 bits 60 bits
12 carriers/OFDM symbol in Option 36 carriers/OFDM symbol in Option 4
60 carriers in Option 330 carriers in Option 4
Interleaver size = 24
5 OFDM symbols
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 17
- In this case, the interleaving size is 24.
- Thus, the interleaving of 24 can't be completed using 60 bits as shown below figure.
1 2 3 4 5 6
# 1 #2 #3
1 3 5 7 911
13
15
17
19
21
23
2 4 6 810
12
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24
# 1 # 2
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24
#11 #12
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# 5 # 6
49
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# 25 #26
59
60
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#30 #31
69
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#35 #36
67
68
#34
57
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#29
For Example of Option 3 & 4(Continued)
<Interleaving Procedure>
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Propose new formulas for Construction of Symbol number and Pad bits
Slide 18
• We propose new formulas for PAD bits and the number of symbols considering the Interleaving size and FDS repetition.
- refer the document #15-10-0423
NCBPS = Ncbps
NDBPS = NCBPS * R
NPAD = NDBPS * ceiling ((8*LENGTH + 6)/NDBPS) - (8*LENGTH +
6)
NSYM = NsF * ceiling ((8*LENGTH + 6)/NDBPS)
-R: Coding rate
-NsF: Spreading Factor of FDS
-Ncbps: Coded Bits per OFDM symbol at interleaver
-NCBPS : Coded Bits per NsF OFDM symbols at IFFT
-NDBPS : DATA Bits per NsF OFDM symbols at IFFT
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Symbol Number and Pad bits in PHY Header fields by the new proposed formulas
Slide 19
• Construction of Symbol number and Pad bits of PHY Header using the new proposed formulas
Optiondata rate
(Kbps)Modulation
Coding
rate
(R)
FDS
(NSF)
Coded Bits
/OFDM symbol
at interleaver
Ncbps
Coded Bits
/NSF OFDM symbol
at IFFT
NCBPS
DATA Bits
/NSF OFDM symbol
at IFFT
NDBPS
NPAD NSYM
100 BPSK 0.5 4 96 96 48 12 4
50 BPSK 0.5 4 48 48 24 12 8
50 BPSK 0.5 2 24 24 12 0 6
50 QPSK 0.5 2 24 24 12 0 6
50 DCM 0.75 1 8 8 6 0 65
1
2
3
4
Option 1
NCBPS= 96
NDBPS= 48
NPAD = 48 * ceil (36/48) - (36) = 12
NSYM = 4 * ceil (36/48) = 4
Option 2
NCBPS= 48
NDBPS= 24
NPAD = 24 * ceil (36/24) - (36) = 12
NSYM = 4 * ceil (36/24) = 4 *2 = 8
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 20
For Example of Option 1
- According to the new proposed formulas,
The bit number of PHY header fields including pad bits is 48, and then it
increases 96 bits after Convolutional encoder.
<Block diagram of PHY Header Construction>
DATAEncoder
(R=½)Interleaver
SubcarrierModulation
Mapper
FDS ( X4 )
IFFTCyclicPrefix
InsertionFiltering
DAC/RF Transceiver
/PA
Pad : 12 bits
Header : 36 bits
48 bits 96 bits 96 bits
96 carriers
24 carriers/OFDM
symbol
4 OFDM symbols
Interleaver size = 96
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 21
For Example of Option 1(Continued)
- In this case, the interleaving size is 96 .
- Thus, the interleaving of 96 can be completed using 96 bits of PHY
header fields as shown below figure .
<Interleaving Procedure>
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 22
For Example of Option 2
- According to the new proposed formulas,
The bit number of PHY header fields including pad bits is 48, and then it
increases 96 bits after Convolutional encoder.
<Block diagram of PHY Header Construction>
DATAEncoder
(R=½)Interleaver
SubcarrierModulation
Mapper
FDS ( X4 )
IFFTCyclicPrefix
InsertionFiltering
DAC/RF Transceiver
/PA
Pad : 12 bits
Header : 36 bits
48 bits 96 bits 96 bits
96 carriers
12 carriers/OFDM
symbol
8 OFDM symbols
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 23
For Example of Option 2(Continued)
- In this case, the interleaving size is 48 .
- Thus, the interleaving of 48 can be completed using 96 bits of PHY
header fields as shown below figure .
<Interleaving Procedure>
1 2 3 4
1 5 913
17
21
25
29
33
37
41
45
4 812
16
20
24
28
32
36
40
44
48
# 1 # 2 # 12
# 1 # 4
5 6 7 845
46
47
48
# 11
41
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# 13 # 14 # 24
# 5 # 8
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# 23
89
90
91
92
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
PSDU fields for OFDM
Slide 24
• The maximum PSDU are 2047bytes
• For convenience of explanation, PSDU Length of 3 bytes is assumed.
PSDU : 3 Bytes Tail bits Pad bits
6 Zero Bits(Tail Bits)
Pad Bits
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 25
- If the PSDU Length of 3bytes is assumed in 50Kbps mode of Option 3
and 4, the number of Symbol and Pads bits can be calculated by the
new proposed formulas.
NCBPS = 24 NDBPS = 24 * ½ = 12 NPAD = 12 * ceiling ((8*3 + 6)/12) - (8*3 + 6) = 6 NSYM = 2 * ceiling ((8*3 + 6)/12) = 6
For Example of Option 3 & 4
Optiondata rate
(Kbps)Modulation
Coding
rate
(R)
FDS
(NSF)
Coded Bits
/OFDM symbol
at interleaver
Ncbps
Coded Bits
/NSF OFDM symbol
at IFFT
NCBPS
DATA Bits
/NSF OFDM
symbol
at IFFT
NDBPS
NPAD NSYM
50 BPSK 0.5 2 24 24 12 6 6
50 QPSK 0.5 2 24 24 12 6 6
3
4
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 26
- PHY Payload of 36 bits including PSDU, tail bits and Pad bits increase (3*8 + 6 +6)*2 = 72 bits after Convolutional encoder.
<Block diagram of PSDU Construction>
For Example of Option 3 & 4(Continued)
DATA ScramblerEncoder
(R=½)Puncturer Interleaver
SubcarrierModulation
Mapper
FDS ( X2 )
IFFTCyclicPrefix
InsertionFiltering
DAC/RF Transceiver
/PA
If R=1/2
PSDU 3byte + tail bits
3*8+6 = 30 bits Pad : 6 bits
36 bits 72 bits 72 bits
12 carriers/OFDM symbol in Option 36 carriers/OFDM symbol in Option 4
72 carriers in Option 336 carriers in Option 4
Interleaver size = 24
6 OFDM symbols
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Slide 27
- In this case, the interleaving size is 24.
- Thus, the interleaving of 24 can be completed using 72 bits as shown below figure.
For Example of Option 3 & 4(Continued)
<Interleaving Procedure>
1 2 3 4 5 6
# 1 #2 #3
1 3 5 7 911
13
15
17
19
21
23
2 4 6 810
12
14
16
18
20
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24
# 1 # 2
21
22
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24
#11 #12
49
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# 5 # 6
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# 25 #26
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#30 #31
69
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#35 #36
67
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#34
57
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#29
Submission Sangsung Choi & Cheolho Shin, ETRI
IEEE 802.15-10-0501-00-004g
Conclusion
Slide 28
July, 2010
• The generation formulas for the number of symbol and PAD bits
in page 67 of draft standard can not consider the Interleaver
size and FDS repetition.
- In several data rate modes using FDS, Interleaving can’t be completed.
• Then, we propose new generation formulas for PAD bits and the
number of symbol considering the Interleaver size and FDS
repetition.
- The proposed formulas can be good solution for all data rate modes of
all Options.