LDPC Investigation for IEEE 802.11bd Technology in March 2019

In March 2019, the document IEEE 802.11-19/0346r3 delves into the investigation of LDPC (Low-Density Parity-Check) codes for the advancement of 11bd technology. The authors from Marvell explore the potential benefits of LDPC over BCC (Block Code Concatenation) in achieving better sensitivity for 802.11bd. Detailed comparisons and simulations are conducted to showcase the advantages of LDPC coding, demonstrating notable gains in various scenarios such as rural and urban environments. LDPC has been a key technology since 802.11n, and its adoption in 802.11bd holds promise for improved performance in WiFi products.

• LDPC
• IEEE 802.11bd
• Marvell
• WiFi technology
• Coding comparison

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1. March 2019 doc.: IEEE 802.11-19/0346r3 LDPC Investigation for 11bd Date: 2019-03-14 Authors: Name Affiliations Address Phone email Prashant Sharma Marvell 5488 Marvell Ln, Santa Clara, CA 95054 psharma@marvell.com Rui Cao ruicao@marvell.com Hongyuan Zhang hongyuan@marvell.com Submission Slide 1 Rui Cao and etc., Marvell

2. March 2019 doc.: IEEE 802.11-19/0346r3 Introduction In January meeting, LDPC was suggested as a promising PHY technology for 11bd [1, 2]. Some preliminary studies were provided together with some other PHY features. In this contribution, we will further investigate the benefits of LDPC over BCC in 11bd. Submission Slide 2 Rui Cao and etc., Marvell

3. March 2019 doc.: IEEE 802.11-19/0346r3 LDPC LDPC has been adopted since 802.11n, and become mature in most WiFi products. It is a low-hanging fruit for 802.11bd to achieve better sensitivity by adopting LDPC codes. The same LDPC code design as 802.11n/ac can be used. The coding type may be signaled in the NGV SIG field. Prominent LDPC coding gain over BCC is demonstrated for AWGN and various 11n channel Models in [3]. We simulate LDPC vs BCC under C2C channels. To make apple-to-apple comparison, genie data aided channel update is implemented in both cases, so to have the same Doppler effect, and the same channel update latency and period are chosen for both codes. Pure coding gain can be evaluated in term of PER Submission Slide 3 Rui Cao and etc., Marvell

4. March 2019 doc.: IEEE 802.11-19/0346r3 Simulations Settings 1x1-1SS, 10MHz DSRC channel Car2Car Doppler channel model [4] Number of data bits: 300 Bytes Genie-aided carrier sensing and timing NGV + LDPC vs 11p BCC NGV PPDU: 11ac 20MHz DC2, 11ac LDPC coding NGV PPDU has ~0.35dB worse per-tone SNR. Genie-aided Doppler Channel Update Shortest theoretical channel update delay and period for BCC Tracking latency of 2 symbols Tracking period of 1 symbol Submission Slide 4 Rui Cao and etc., Marvell

5. March 2019 doc.: IEEE 802.11-19/0346r3 Rural LOS LDPC vs BCC: 1x1-1ss, Rural-LOS, 300Bytes 0 10 -1 10 PER BPSK-1/2 QPSK-1/2 QPSK-3/4 16QAM-1/2 16QAM-3/4 64QAM-2/3 64QAM-3/4 11p-BCC 11ac-LDPC -2 10 -3 10 0 5 10 15 20 25 30 SNR (dB) 11ac-LDPC shows SNR gain 1.5~4dB among all MCSs Submission Slide 5 Rui Cao and etc., Marvell

6. March 2019 doc.: IEEE 802.11-19/0346r3 Urban Approaching LOS LDPC vs BCC: 1x1-1ss, Urban-Approaching-LOS, 300Bytes 0 10 BPSK-1/2 QPSK-1/2 QPSK-3/4 16QAM-1/2 16QAM-3/4 64QAM-2/3 64QAM-3/4 11p-BCC 11ac-LDPC -1 10 PER -2 10 -3 10 0 5 10 15 20 25 30 35 SNR (dB) 11ac-LDPC shows SNR gain 1~4dB among all MCSs Submission Slide 6 Rui Cao and etc., Marvell

7. March 2019 doc.: IEEE 802.11-19/0346r3 Urban Crossing NLOS LDPC vs BCC: 1x1-1ss, Urban-Crossing-NLOS, 300Bytes 0 10 BPSK-1/2 QPSK-1/2 QPSK-3/4 16QAM-1/2 16QAM-3/4 64QAM-2/3 64QAM-3/4 11p-BCC 11ac-LDPC -1 10 PER -2 10 -3 10 0 5 10 15 20 25 30 35 SNR (dB) 11ac-LDPC shows SNR gain 1~4dB among all MCSs Submission Slide 7 Rui Cao and etc., Marvell

8. March 2019 doc.: IEEE 802.11-19/0346r3 Highway LOS LDPC vs BCC: 1x1-1ss, Highway-LOS, 300Bytes 0 10 BPSK-1/2 QPSK-1/2 QPSK-3/4 16QAM-1/2 16QAM-3/4 64QAM-2/3 64QAM-3/4 11p-BCC 11ac-LDPC -1 10 PER -2 10 -3 10 0 5 10 15 20 25 30 35 SNR (dB) 11ac-LDPC shows SNR gain 1.5~4dB among all MCSs Submission Slide 8 Rui Cao and etc., Marvell

9. March 2019 doc.: IEEE 802.11-19/0346r3 Highway NLOS LDPC vs BCC: 1x1-1ss, Highway-NLOS, 300Bytes 0 10 BPSK-1/2 QPSK-1/2 QPSK-3/4 16QAM-1/2 16QAM-3/4 64QAM-2/3 64QAM-3/4 11p-BCC 11ac-LDPC -1 10 PER -2 10 -3 10 0 5 10 15 20 25 30 35 40 SNR (dB) 11ac-LDPC shows SNR gain 1~4dB among all MCSs Submission Slide 9 Rui Cao and etc., Marvell

10. January 2019 doc.: IEEE 802.11-19/0346r3 Summary LDPC coding is revisited and evaluated under C2C channel models. Simulations show prominent SNR gain, 1~4dB, by changing the coding from BCC to LDPC. LDPC codes are mature in 802.11 standards and products. Propose to add LDPC coding to 11bd standards. Submission Slide 10 Rui Cao and etc., Marvell

11. March 2019 doc.: IEEE 802.11-19/0346r3 Reference [1] Rui Cao and etc., Potential PHY Designs for NGV , IEEE 802.11-19/0016r0. [2] Dongguk Lim and etc., Consideration on Features for 11bd , 802.11-19/0009r0. [3] Aleksandar Purkovic, and etc., LDPC vs Convolutional Codes for 802.11n applications performance comparison , 11-04/0071r01. [4] Prashant Sharma and etc. Simulation of NGV Channel Models , 11-19/0017r4 Submission Slide 11 Rui Cao and etc., Marvell

12. March 2019 doc.: IEEE 802.11-19/0346r3 Straw Poll 1 Do you agree to add the following text into Section 3 of SFD? 11bd amendment shall support LDPC Y: 36 N: 0 A: 9 Submission Slide 12 Rui Cao and etc., Marvell

13. March 2019 doc.: IEEE 802.11-19/0346r3 Straw Poll 2 Do you agree to add the following text into Section 3 of SFD? 11bd amendment shall support LDPC code, with the same coding method as defined in IEEE 802.11-2012 section 19.3.11.7 (LDPC Codes) Y: 30 N: 2 A: 11 Submission Slide 13 Rui Cao and etc., Marvell

14. March 2019 doc.: IEEE 802.11-19/0346r3 Motion Move to add the following text into Section 3 of SFD: 802.11bd amendment shall support LDPC Move: Second: Result: Submission Slide 14 Rui Cao and etc., Marvell

15. March 2019 doc.: IEEE 802.11-19/0346r3 Appendix: AWGN LDPC vs BCC: 1x1-1ss, AWGN, 2000 Bytes 0 10 BPSK-1/2 QPSK-1/2 QPSK-3/4 16QAM-1/2 16QAM-3/4 64QAM-2/3 64QAM-3/4 11p-BCC 11ac-BCC 11ac-LDPC -1 10 PER -2 10 -3 10 0 5 10 15 20 25 SNR (dB) NGV receiver uses channel smoothing across LLTF and VHT-LTF LDPC shows 2~3dB SNR gain over BCC for 11ac OFDM format Submission Slide 15 Rui Cao and etc., Marvell