1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Ranging Signal Waveforms: Non-coherent Ranging Proposals (Overview)
Date Submitted: [13 June, 2005]
Source: [Zafer Sahinoglu] Company [Mitsubishi Electric.]
Address [201 Broadway, Cambridge, MA 02139]
Voice ], FAX: [ ],
Re: [ a.]
Abstract: [Overview of ranging receiver architectures for non-coherent reception]
Purpose: [To promote discussion in a.]
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

2. Outline
Signal Waveforms
Receiver Architecture
Comparison of Proposals
Issues in Non-coherent ranging
Suggestions

3. There are 4 waveforms under consideration
Signal Waveforms
There are 4 waveforms under consideration
Bulk PPM
IR-TR (Impulse Radio Transmitted Reference)
MTOK sequences
TH-IR (Time Hopping Impulse Radio)

4. Option-I One Bit The Other Bit Always Empty Always Empty Always Empty
100ns
8-chip times: 150ns
100ns
8-chip times: 150ns
The Other Bit
Always Empty
Always Empty
Always Empty
8-chip times: 150ns
100ns
Enough long not to cause IFI : 100ns
8-chip times: 150ns

5. Option-II Ts = 500ns « 11 » 2-PPM + TR base M = 2 « 01 »
« 11 »
2-PPM + TR base
M = 2
One bit/symbol
« 01 »
« 10 »
« 00 »
(coherent decoding possible)

6. Ternary Signaling for Synchronization & Ranging
Option-III
To compare fairly, with option-I, which has 8 pulses in 500ns, the PRI for option-III is 62.5ns
Ternary Signaling for Synchronization & Ranging
Pulse Repetition Interval ~ 62.5ns
-Common signaling (Mode 1) for ALL Detectors
-Receiver-specific signaling (Mode 2) for ED 1 2 3 4 5 6 7 8 30 31
…………………………
Non-inverted pulses are blue,
Inverted pulses are green.
Synchronisation / Ranging
preamble = Binary Base
Sequence repeated
For K times…
……………
……………
Symbol Interval =1937.5ns
Symbol Interval =1937.5ns
Tuesday, November 27, 2018

7. Option-IV Illustration: Use of an 8-ary Time Hopping code of length 4
Use of such a TH code combined with the band plan may allow to handle the SOP issue
Code order and length are scalable to meet different requirements
Tp = 4ns, Tc = 20 ns, Tf = 160 ns, Tsymbol = 640 ns
PRP ± TH Tp Tc Tf

8. Recommended Architecture for Ranging with Non-Coherent Rx (MERL)
(No FFT routine is needed, being different from doc#0269)
Energy image generation
Removes interference
2-4ns
Length-3 Vertical Median or Minimum Filtering
1D to 2D Conversion
LPF /
integrator
BPF
( )2
ADC
2D to 1D Conversion with Energy Combining
TOA Estimator

9. Recommended Architecture for Ranging with Non-Coherent Rx (I2R)
TOA Estimator
Energy image generation & interference suppression
2D-1D conver-sion
interference suppression
2-4ns
Energy combining across symbols
1D-2D conversion
Sliding Correlator
LPF /
integrator
BPF
( )2
ADC
Bipolar Template

10. Recommended Architecture for Ranging with Non-Coherent Rx (FT R&D)
Time base
1-2ns accurate
4ns
Time-stamping
LPF /
integrator
Analog
Comparator
"Path-arrival dates" table
BPF
( )2
1D to 2D Conversion
Filtering + Assumption/path selection
Assumption path synchronization Matrix
TOA measure

11. Signal energy collection architecture is the same
Commonalities
Signal energy collection architecture is the same
Sampling resolution is the same (e.g., 2ns-4ns)
1D to 2D conversion for interference removal seems to be adopted in all the architectures
BPF
LNA
ADC
Signal
RF Part
Analog comparator
Energy image generation
1D to 2D Conversion
Interference removal
2D to 1D Conversion
TOA Estimator

12. Ranging Architecture Comparison
MERL architecture works with all signal waveforms
Its performance would be
Very high in Option-4 (FT)
High in Option-1 (MERL, TDC)
Moderate in Option-3 (I2R)
I2R and MERL receiver architectures have good support for scalability in TDOA applications (unsure about FT)
Receive from TDOA stations simultaneously, without changing the RF front
Decode TOA from each station at the post filtering
Energy Matrix Generator-I
Post Filtering
2D-1D conversion
TOA Est.
Post Filtering
Energy Matrix Generator-M
2D-1D conversion
TOA Est.

13. Feature Comparison Pulse OOK (option-III) Burst PPM (option-I) TH-IR
Signaling
Spaced out pulse seq
Clustered pulse seq
Time Hopping Impulse Radio
Energy Integration period (for ranging)
2~4ns
2ns-4ns
without SOP
TBD
with SOP
Good in com. Mode
Questionable in ranging
(Sufficient processing gain to handle)
good in ranging mode
(Not much processing gain to handle the comm. mode)
Good in ranging and comm. Pulse amplitudes may be a drawback
Common signaling for preamble
No Time hopping
Time Hopping
Additional complexity for Coherent receiver to receive preamble with common signaling No
Yes (2 layer sync, TH then code de-spreading) TH
Inter-pulse interference during ranging operation
Less due to long PRI
33MHz PRF or ~16MHz PRF)
More due to small inter pulse interval
Sampling rate in ranging
Low in transmitter
High in receiver
Low in receiver
High in transmitter

14. Issues in Non-coherent ranging
Square-law operation is non-linear
Relative improvement in SNR by statistical multiplexing is higher, when pulse amplitudes are higher
Option-1 requires longer preamble than option-4 to achieve the same SNR level
Error floor can be lowered for the same SNR level, by having narrower integration intervals -
Preamble length
For a given sampling resolution
Mean absolute ranging error
Higher sampling resolution +
EbN0
25dB

15. Suggestions
Test the ranging performance of the three proposals at a sufficiently high SNR without SOP
To see the best achievable ranging accuracy with 90% confidence level
To derive the required preamble length
Test the ranging performance of the three proposals at the 90% level SNR from step-1 with SOP (SIR=0dB, 10dB)
Quantify the degradation in ranging accuracy and confidence level