1. 2019/5/7
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [FEC coding for TG4a]
Date Submitted: [12 October 2005]
Source: [Kenichi Takizawa, Huan-Bang Li, and Ryuji Kohno] Company [NICT]
Voice:[ ],
Abstract: [FEC coding proposal]
Purpose: [Assist the group in the selection of a modulation scheme]
Notice: This document has been prepared to assist the IEEE P 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 P
Takizawa, Li, and Kohno (NICT)

2. 2019/5/7
FEC Option 1
Takizawa, Li, and Kohno (NICT)

3. Modulation : bursts and peak PRF
2019/5/7
Modulation : bursts and peak PRF
TB = burst duration
= One code = 8 pulses
Ts = Duration of one symbol =
64 TB (PRF=494MHz)
32 TB (PRF=247MHz)
~ 1us
PRF = 494MHz:
1 pulse = 1 chip ~ 2ns; 1TB ~ 16ns
PRF = 247MHz
1 Pulse = 2 chips ~4ns; 1TB ~ 32ns
Takizawa, Li, and Kohno (NICT)

4. Modulation : 2PPM+BPSK 2019/5/7 non-coherent coherent00
0 - 01 10
1 - 11
Guard time for channel delay spread (260ns)
Code scrambling interval
coherent
non-coherent S 1 31 32 33 63 15 16 47 48 -S 1 31 32 33 63 15 16 47 48 S 1 31 32 33 63 15 16 47 48 -S 1 31 32 33 63 15 16 47 48
One code burst with PRF = 494 MHz
One code bust with PRF = 247 MHz
Takizawa, Li, and Kohno (NICT)

5. Guard time for channel delay spread (130ns)
2019/5/7
Modulation : 4PPM+BPSK
Guard time for channel delay spread (130ns) C NC
000
00 -
001
010
01 -
011
110
11 -
111
100
10 -
101 S 31 32 63 7 16 39 40 8 15 24 23 47 48 56 57 -S 31 32 63 7 16 39 40 8 15 24 23 47 48 56 57 S 31 32 63 7 16 39 40 8 15 24 23 47 48 56 57 -S 31 32 63 7 16 39 40 8 15 24 23 47 48 56 57 S 31 32 63 7 16 39 40 8 15 24 23 47 48 56 57 -S 31 32 63 7 16 39 40 8 15 24 23 47 48 56 57 S 31 32 63 7 16 39 40 8 15 24 23 47 48 56 57 -S 31 32 63 7 16 39 40 8 15 24 23 47 48 56 57
One code burst with PRF = 494 MHz One code bust with PRF = 247 MHz
Takizawa, Li, and Kohno (NICT)

6. K=3 Convolutional coding with 2PPM+BPSK
2019/5/7
K=3 Convolutional coding with 2PPM+BPSK
~1000ns
code
0..0
0..0
0..0
0..0
0..0
0..0
0..0 1
0..0
0..0
0..0
0..0
code
0..0
0..0
0..0 D D
0 -> +1
1 -> -1
Coherent receiver
K=3 Viterbi decoder (coding rate = 1/2)
Non-Coherent receiver
~1000ns
Uncoded
code
0..0
0..0
0..0
0..0
0..0
0..0
0..0 1
0..0
0..0
0..0
0..0
code
0..0
0..0
0..0 D D
Takizawa, Li, and Kohno (NICT)

7. K=3 Convolutional coding with 4PPM+BPSK
2019/5/7
K=3 Convolutional coding with 4PPM+BPSK
~1000ns 00
code
0..0
0..0
0..0
0..0
0..0
0..0
0..0 01
0..0
0..0
code
0..0
0..0
0..0
0..0
0..0 10
0..0
0..0
0..0
0..0
code
0..0
0..0
0..0 11
0..0
0..0
0..0
0..0
0..0
0..0
code
0..0 D D
0 -> +1
1 -> -1
Coherent receiver
K=3 Viterbi decoder (coding rate = 1/3)
Non-Coherent receiver
K=3 Viterbi decoder (coding rate = 1/2)
This FEC code is suitable for non-coherent receiver. D D
Takizawa, Li, and Kohno (NICT)

8. K=4 Convolutional coding with 4PPM+BPSK
2019/5/7
K=4 Convolutional coding with 4PPM+BPSK
~1000ns 00
code
0..0
0..0
0..0
0..0
0..0
0..0
0..0 01
0..0
0..0
code
0..0
0..0
0..0
0..0
0..0 10
0..0
0..0
0..0
0..0
code
0..0
0..0
0..0 11
0..0
0..0
0..0
0..0
0..0
0..0
code
0..0 D D D
0 -> +1
1 -> -1
Coherent receiver
K=4 Viterbi decoder
Non-Coherent receiver 00
code
0..0
0..0
0..0
0..0
0..0
0..0
0..0
Punctured K=2 Viterbi decoder 01
0..0
0..0
code
0..0
0..0
0..0
0..0
0..0 10
0..0
0..0
0..0
0..0
code
0..0
0..0
0..0 11
0..0
0..0
0..0
0..0
0..0
0..0
code
0..0 D D D
Takizawa, Li, and Kohno (NICT)

9. Simulation results on AWGN
2019/5/7
Simulation results on AWGN
Takizawa, Li, and Kohno (NICT)

10. Eb/N0 required for PER of 1% (AWGN)
2019/5/7
Eb/N0 required for PER of 1% (AWGN)
Coherent
Non-coherent
2PPM+BPSK
(K=3)
6.3dB
13.6dB
4PPM+BPSK
7.8dB
10.6dB
(K=4)
5.8dB
11.7dB
Takizawa, Li, and Kohno (NICT)

11. (soft-decision decoding)
2019/5/7
Complexity comparison
Coding rates
Gate counts
(soft-decision decoding)
Clock speed*
2PPM+BPSK
(K=3)
1/2 (coh.)
1 (non-h)
3K (coh.)
0 (non-h)
2M (coh.)
1M (non-h.)
4PPM+BPSK
1/3 (coh.)
1/2 (non-h)
4.5K (coh.)
3K (non-h)
3M (coh.)
2M (non-h.)
(K=4)
9K (coh.)
6K (non-h)
*: 4PPM+BPSK c1 c2
4PPM
DEC c0 c1 c2 b
FEC
DEC c0 3M
1Mbps
BPSK
DEC
1/3-rate code
Takizawa, Li, and Kohno (NICT)

12. Additional information (if we allow iterative processing)
2019/5/7
Additional information (if we allow iterative processing)
Takizawa, Li, and Kohno (NICT)

13. Systematic Convolutional Encoder
2019/5/7
K=3 code with 2PPM + BPSK using iteration
4BOK mapping
~1000ns
code
0..0
0..0
0..0
0..0
0..0
0..0
0..0
Systematic 1
0..0
0..0
0..0
0..0
code
0..0
0..0
0..0
Systematic Convolutional Encoder
K=3
R=1/2
interleaver
Parity
0 -> +1
1 -> -1
interleaver
Coherent Receiver: Convolutional code Rate = ½
Non Coherent Receiver: Uncoded
Coherent receiver
Iterative demapping and decoding (IDD) between 4BOK demapper and K=3 half-rate Viterbi decoder
ADC
code
correlator
4BOK
decoder
FEC
decoder
deinterleaver
interleaver
code correlator outputs for each time slot
Takizawa, Li, and Kohno (NICT)

14. Improved performance with iteration
2019/5/7
Improved performance with iteration
Generation polynomial
G=[1,5/7]
2dB gain by 3 iterations
Takizawa, Li, and Kohno (NICT)

15. K=3 code with 4PPM + BPSK using iteration
2019/5/7
K=3 code with 4PPM + BPSK using iteration
~1000ns 00
code
0..0
0..0
0..0
0..0
0..0
0..0
0..0
systematic
Systematic Convolutional Encoder 1
K=3
R=1/2 01
0..0
0..0
code
0..0
0..0
0..0
0..0
0..0
parity 10
0..0
0..0
0..0
0..0
code
0..0
0..0
0..0
interleaver
systematic 11
0..0
0..0
0..0
0..0
0..0
0..0
code
0..0
Systematic Convolutional Encoder 2
K=3
R=1/2
Not use
parity
0 -> +1
1 -> -1
Coherent Receiver: Convolutional code Rate = 1/3
Non Coherent Receiver: Convolutional code Rate = 1/2
Coherent receiver
Iterative decoding between the two K=3 half-rate decoders
ADC
code
correlator
4BOK
decoder
FEC
decoder 1
FEC
decoder 2
deinterleaver
interleaver
Takizawa, Li, and Kohno (NICT)

16. Improved performance with iteration
2019/5/7
Improved performance with iteration
Generation polynomial
G=[1,5/7]
2.4dB gain by 4 iterations
Takizawa, Li, and Kohno (NICT)

17. Complexity comparison with FEC 1
2019/5/7
Complexity comparison with FEC 1
Coherent detection
Coding rates
Gate counts
Clock speed
(serial input*)
Required Eb/N0
for PER of 1%
2PPM+BPSK
(K=3, iterative)
1/2 8K
(4BOK+FEC) 2M
3.8dB
(K=3, FEC 1) 3K
6.3dB
4PPM+BPSK
1/3
15K
(2 FEC DECs) 3M
3.7dB
4.5K
7.8dB
2.5dB
4.1dB
Takizawa, Li, and Kohno (NICT)

18. Conclusion FEC Option 1 Iterative processing
2019/5/7
Conclusion
FEC Option 1
K=3 and 4 convolutional codes for 4PPM+BPSK modulation
K=3 code is suitable for Non-coherent receiver
K=3 convolutional code for 2PPM+BPSK modulation
This code provides the best performance among them for coherent receiver
Low-complexity
Iterative processing
If we approve the use of a bit-wise interleaver, we can use iterative processing at coherent receivers.
Trade-off the coding gain for the decoding complexity
Takizawa, Li, and Kohno (NICT)