Jul 12, 2010 07/12/10 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Adaptive Preamble Length Mode for UWB HRP Ranging Date Submitted: September 2018 Source: Yi Yang, Jong-Hoon Jang, Moon-Seok Kang, Jonghyo Lee, Aditya V. Padaki, Boon Loong Ng Company: Samsung Email: yi83.yang@samsung.com, jh0.jang@samsung.com, moonseok.kang@samsung.com, jonghyo.lee@samsung.com, a.padaki@samsung.com, b.ng@samsung.com Abstract:[] Purpose: [] 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 Slide 1 Page 1

Note: Notation/nomenclature based on Overview Introduction Experimental Results to Motivate use of Adaptive Preamble Length Proposed Frame Format in PHR Proposed PIB for Adaptive Preamble Length Conclusions Note: Notation/nomenclature based on https://mentor.ieee.org/802.15/dcn/18/15-18-0286-01-004z-hrp-uwb-srdev- ppdu-text-contribution.docx and https://mentor.ieee.org/802.15/dcn/18/15-18-0335-00-004z-srdev-ppdu-for- enhanced-impulse-radio.pptx

Current Preamble Length SYNC part of SHR is static value set by higher layers Receiver calculates the first path of Channel Impulse Response(CIR) from Preamble to get the ranging info Higher layer oblivious to the required Number of symbols (Nsym) in SHR as because environment is always changing Following issues are observed: Long preambles may be used even in good LOS scenarios Wastes power and makes channel busy Short preambles may be used even in bad NLOS scenarios Lose the performance ex: ranging accuracy

Experimental Test 1: NLOS True Distance: 3.5m Nsym=64 Nsym=4096 Nsym=64, results in distance error for NLOS Nsym=4096, gives much better accuracy

Experimental Test 2: LOS Nsym 128 and Nsym 1024 achieve almost the same accuracy Nsym Tsym(us) LOS(cm) 128 130.4 340 +/- 3.93 1024 1042.1 340 +/- 4.07

Current Developments 802.15.4a 802.15.4z HRP Bits: 0 1-10 11 Reserved   Bits: 0 1-10 11 Reserved Frame Length Ranging  

Proposal To achieve the best trade off between ranging accuracy and power consumed, dynamically change the preamble duration based on (not exhaustive list) Setting ranging confidence level(CI) the S/N of 1st path Data rate

Proposed Workflow

Proposed PHR frame structure Bits:0-1 2-10 11 12 13-18 Data Rate Frame Length Ranging Preamble Mode SECDED OR 0 Static 1 Dynamic 0~511 byte Bits:0-1 2-11 11 12 13-18 Data Rate Frame Length Ranging Preamble Mode SECDED 0 Static 1 Dynamic 0~1023 byte For the 128 MHz PRF mode, the proposed change in PHR is Bits: 0 1-10 11 12 Reserved Frame Length Ranging Preamble Mode

Proposed PIB for Adaptive Preamble Mode Attribute Type Range Description phyHrpUwbAdaptivePreabmleLengthMode Boolean FALSE,TRUE Enable Adaptive Preamble Length modes phyHrpUwbAdaptivePreabmleLengthConfidenceLevel 3bit 55~99 Confidence Level for the Adaptive Preamble Length modes Confidence Level Bit2 Bit1 Bit0 Reserved 1 55% 85% 92% 99% Low Medium High

Conclusions Static SYNC length in the preamble may result in low ranging accuracy or high power consumption This can be optimized by enabling adaptive preamble mode Frame structure and PIB for adaptive preamble mode is proposed for performance optimized mode