Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
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Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [ TDOA/TWR Positioning and Ranging Techniques Based on Noncoherent OOK PHY] Date Submitted: [09 NOV , 2004]

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Project ieee p802 15 working group for wireless personal area networks wpans 5078694

Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

Submission Title: [TDOA/TWR Positioning and Ranging Techniques Based on Noncoherent OOK PHY]

Date Submitted: [09 NOV, 2004]

Source: [Kwan-Ho Kim(1), Sungsoo Choi(1), Youngjin Park(1), Hui-Myoung Oh(1), Yo-Ahn Shin(2), Wonchul Lee(2), and Ho-In Jeon(3)] Company: [(1)Korea Electrotechnology Research Institute(KERI), (2)Soongsil University(SSU), and (3)Kyoungwon University(KWU)]

Address: [(1)665-4, Naeson 2-dong, Euiwang-City, Kyunggi-do,Republic of Korea (2) 1-1, Sangdo-5-dong, Dongjak-Gu, Seoul, Republic of Korea (3)San 65, Bok-Jeong-dong, Seongnam, Republic of Korea]

Voice:[(1)+82-31-420 6183, (2)+82-2-820-0632, (3)+82-31-753-2533], FAX: [(1)82-31-420 6183, (2)82-2-821-7653, (3)+82-31-753-2532], E-Mail:[(1)[email protected], (2)[email protected], (3)[email protected] won.ac.kr]

Re: []

Abstract:[This document proposes preliminary proposal for the IEEE 802.15.4 alternate PHY standard.]

Purpose:[Preliminary Proposal for the IEEE802.15.4a standard]

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.

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Tdoa twr positioning and ranging techniques based on noncoherent ook phy

TDOA/TWR Positioning and Ranging Techniques Based on Noncoherent OOK PHY

KERI-SSU-KWU

Republic of Korea

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Contents

Contents

  • Noncoherent OOK UWB transceiver with power detection

  • Three modes in the receiver for system performance improvement

  • Asynchronous ranging by round trip time

  • Positioning based on sequential relay transmission

  • Positioning scenarios according to network topologies

  • Parallel window bank for power detection & ranging accuracy improvement

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Proposal overview 1

Proposal Overview(1)

  • Motivation of proposal

    • To satisfy IEEE 802.15.4a technical requirements, it is essential that low power consumption in the UWB system level as well as link level must be achieved

    • Conventional coherent UWB system based on correlator in the receiver can provide fairly good performance

    • However, coherent UWB system is very sensitive to the signal synchronization, and the additional pulse generator is required in the receiver

    • Thus, this system may increase the implementation complexity, and consequently power consumption and system cost

  • To meet low power and low cost requirement, we propose UWB system with OOK (On-Off Keying) modulation and noncoherent detection

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Proposal overview 2

Proposal Overview(2)

  • Pros & cons

    • In the proposed UWB system, unlike the conventional coherent UWB system, the signal demodulation is performed by simply comparing the received signal power with detection threshold

    • It can significantly relieve the strict synchronization requirement in the receiver and also provide with simplified transceiver structure with the minimal power and cost demand, since pulse generator is omitted

    • However, the noncoherent OOK UWB system may yield degraded

    • Bit Error Rate (BER) performance

  • Performance improvement for the noncoherent

  • OOK UWB system is essential

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Proposed noncoherent ook uwb system

Proposed Noncoherent OOK UWB System

Non-coherent OOK UWB system

based on noise power calibration

and signal power detection

Data repetition and multipath

combining for performance

improvement

Three modes in the receiver for

compensation of performance

degradation

(calibration/timing/operation)

UWB Transmitter

Pulse

Generator

Input Bit

Data

OOK

Sequence

Repetition

Modulation

Calibration Mode

(

C

a

l

Threshold

Noise

i

b

Control

Measuring

r

a

t

i

o

n

M

o

/

Timing Mode

d

T

e

i

m

S

i

Coarse Pulse Position Estimation

w

n

i

g

t

c

/

h

Operation Mode

O

p

e

r

P

a

o

t

Receiving

i

w

Multipath

o

e

Data

n

r

Combining

)

Gathering

D

e

t

e

c

t

i

o

n

Decision

Output Bit

Stage

Sequence

UWB Receiver

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Pulse repetition based on edge triggering

Pulse Repetition Based on Edge Triggering

Pulse repetition for data transmission

  • OOK modulation can be easily implemented by generating UWB pulse based on edge triggering

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Proposed three modes in the receiver

Proposed Three Modes in the Receiver

Signal processing in three modes

Calibration Mode

Timing Mode

Operation Mode (R=2)

Receiving Data

Preamble

Gathering

Transmission

Signal

Interval

“1”

“1”

“0”

Multipath

Noise Only (No Data)

Combining

Noise Power Level

Coarse Estimation

Demodulation of the

Measurement by

of Pulse Position &

Received Signal Based

Buffering & Averaging

Peak Sample Position

on Power Detection

Final Bit Decision by

Threshold Reset

Multipath Combining &

for Bit Decision

Receiving Data Gathering

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


More details in the operation mode 1

More Details in the Operation Mode (1)

Operation mode description

Simple

  • Decision statistics

    • : Number of pulse repetitions per data bit

    • : Number of multipath components for combining

    • : Received signal power corresponding to the ’th path

    • of the ’th transmitted pulse

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


More details in the operation mode 2

More Details in the Operation Mode (2)

  • Threshold value for bit decision (no pulse repetition & no multipath combining)

    • : Parameter relative to the average power and power

    • variance of the first path

    • : Noise power measured by noise calibration mode

  • Threshold value (pulse repetition & multipath combining)

  • Threshold value (only pulse repetition)

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Asynchronous ranging scheme

Asynchronous Ranging Scheme

  • Synchronous ranging

    • One way ranging

    • Simple TOA/TDOA measurement

    • Universal external clock

  • Asynchronous ranging

    • Two way ranging

    • TOA/TDOA measurement by RTTs

    • Half-duplex type of signal exchange

TOF : Time Of Flight

RTT : Round Trip Time

SHR : Synchronization Header

But, High

Complexity

Asynchronous Ranging

Synchronous Ranging

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Project ieee p802 15 working group for wireless personal area networks wpans 5078694

Proposed Positioning Scheme

Features- Sequential two-way ranging is executed via relay transmissions- PAN coordinator manages the overall schedule for positioning- Inactive mode processing is required along the positioning- PAN coordinator may transfer all sorts of information such as observed - TDOAs to a processing unit (PU) for position calculationBenefits- It does not need pre-synchronization among the devices- Positioning in mobile environmentis partly accomplished

P_FFD3

P_FFD2

TOA

24

TOA

34

RFD

PAN

coordinator

TOA

14

PU

P_FFD : Positioning Full Function Device

RFD : Reduced Function Device

P_FFD1

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Process of proposed positioning scheme

Process of Proposed Positioning Scheme

TOA measurement

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


More details for obtaining tdoas

RTT12 = T + 2T12

RTT23 = T + 2T23

RTT13 = T12 + 2T + T23 + T13

More Details for obtaining TDOAs

  • Distances among the positioning FFDs are calculated from RTT measurements and known time interval T

  • Using observed RTT measurements and calculated distances, TOAs/TDOAs are updated

T12 = (RTT12 – T)/2

T23 = (RTT23 – T)/2

T13 = (RTT13 – T12 – T23 – 2T)

RTT34 = T34 + T + T34

TOA34 = (RTT34 - T)/2

RTT24 = T23 + T + T34 + T + T24

TOA24 = (RTT24 - T23 - TOA34 - 2T)

TOA14 = (RTT14 - T12 - T23 - TOA34 - 3T)

RTT14 = T12 + T + T23 + T + T34 + T + T14

TDOA12 = TOA14 – TOA24

TDOA23 = TOA24 – TOA34

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Position calculation using tdoas

Position Calculation using TDOAs

  • The range difference measurement defines a hyperboloid of constant range difference

  • When multiple range difference measurements are obtained, producing multiple hyperboloids, the position location of the device is at the intersection among the hyperboloids

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Positioning scenario overview

PAN Coordinator

FFD

RFD

Positioning FFD(P_FFD)

Positioning Scenario Overview

  • Using static reference nodes in relatively large scaled cluster :

    • Power control is required

    • Power consumption increases

    • All devices in cluster must be in inactive data transmission mode

  • Using static and mobile nodes in overlapped small scaled sub-clusters :

    • Sequential positioning is executed in each sub-cluster

    • Low power consumption

    • Associated sub-cluster in positioning mode should be in inactive data transmission mode

  • Case 1

Cluster 1

  • Case 2

Cluster 1

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Positioning scenario for star topology

Positioning Scenario for Star topology

  • Star topology

    • PAN coordinator activated mode

      • Positioning all devices

      • Re-alignment of positioning FFD’s list is not required

    • Target device activated mode

      • Positioning is requested from some device

      • Re-alignment of positioning FFD’s list is required

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Positioning scenario for cluster tree topology

Positioning Scenario for Cluster-tree Topology

  • Cluster-tree topology

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Modifications of mac common frame

Octets : 2

1

0/4/8

variable

2

Frame

control

Sequence

number

Addressing

fields

command frame identifier

Positioning parameter

Command

payload

FCS

MHR

MAC payload

MFR

Modifications of MAC Common Frame

  • Features

    • Frame control field

      • frame type : positioning (new addition)

    • Command frame identifier field

      • Positioning request/response (new addition)

    • Positioning parameter information field

      • Absolute coordinates of positioning FFDs

      • POS range

      • List of positioning FFDs and target devices

      • Power control

      • Pre-determined processing time (T)

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Signal processing for accuracy improvement 1

Signal Processing for Accuracy Improvement (1)

  • Technical requirement for positioning

    • “It can be related to precise (tens of centimeters) localization in some cases, but is generally limited to about one meter”

  • Parameters for technical requirement

    • Pulse duration :

    • Required clock speed

High Cost !

  • Fast ADC clock speed in the receiver is also required for

    noncoherent power detection based OOK reception

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


Signal processing for accuracy improvement 2

Signal Processing for Accuracy Improvement (2)

  • Proposed parallel window bank

    • Fast clock can be implemented by using parallel signal processing windows with low clock speed

  • : Target clock speed

  • : Number of signal processing windows

  • : Window clock speed

  • Example

    • Pulse duration is 3.33 nsec

    • Target speed is 300 MHz

    • Each signal processing

      window has 3 MHz speed

    • Number of windows is 100

Only 3 MHz is

required !!!

K. Kim, S. Choi, Y. Park, H. Oh, Y. Shin, W. Lee, and H. Jeon


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