2019/5/7 Project: IEEE P802.15 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:[+81 46 847 5085], E-Mail: [lee@nict.go.jp] 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 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. Takizawa, Li, and Kohno (NICT)

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

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)

Modulation : 2PPM+BPSK 2019/5/7 non-coherent coherent 00 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)

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)

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)

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)

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)

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

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)

(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)

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

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)

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)

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)

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)

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)

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)