Performance of 3GPP Rel-9 LTE positioning methods Nokia

1 © Nokia Siemens Networks

Performance of 3GPP Rel-9 LTE positioning methods

2nd Invitational Workshop onOpportunistic RF Localization for Next Generation Wireless DevicesJune 13 - 14, 2010

Karri Ranta-ahoSenior Specialist, Radio StandardizationNokia Siemens Networks

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2nd Opportunistic RF Localization for Next Generation Wireless Devices June 13-14, 2010 Worcester Polytechnic Institute Worcester, MA, USA

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Soc Classification level 3 © Nokia Siemens Networks

3GPP Location Standards EvolutionAn Overview

Release 6Privacy Profile

Register,inter-GMLC Lr

interface

Release 7LCS for I-WLAN

including reference to OMA SUPL, A-GNSS (Galileo)

2000 2005 2007

Release 4PS Domain

2001

Release 5EnhancedSubscriber

Privacy

2002

Release 99CS Domain

A-GPS(Phase1)

Release 8A-GNSS

[GLONASS & A-GPS (Phase II),

QZSS]

March 2009

3GPP Release 9 introduced LTE control plane signalling support for LCS

Release 9 Control Plane LCS in EPS (Evolved Packet System)

March 2010

Release 10TBD

Est. March 2011

LTE fromRel-8

onwards


Fallback

Fallback

Primary

Cell ID based positioning + Enhancements• Server knows the geographical locations of the cells • Timing Advance can be used to find the UE’s distance from the eNB antenna• Neighbor cell measurements etc. can be used to increase the accuracy

LTE Positioning Methods- overview3GPP Release 9

OTDOA (Observed Time Difference of Arrival)• UE location can be tri-laterated with the knowledge of three or more eNB’s

–Transmit timings of the cells in the system and their geographical locations–Received time difference of at least two other cells vs. serving cell in the UE

Assisted Satellite positioning (A-GPS, etc)• Network can provide assistance data for faster/more reliable fix

Must get GPS fix from 4 satellites

UE must detect signal of 3 eNBs

Neighbor cells enhance accuracy

A-GPS considered the primary positioning technique in LTE Other techniques used when GPS fix not available


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A-GNSS

OTDOA

• The server asks the UE locate itself• Provides also satellite assistance

data to aid detection• Satellite based positioning is radio

system agnostic• LTE just provides a connection between

the UE and the server

• The server provides the UE with a list of potential neighbors cells to search

• The UE measures and reports OTDOA for detected neighbor cells

• Detection of at least two neighbor eNBsin addition to the serving eNB required

LTE Positioning Methods

Enhanced Cell ID

• The UE reports• The serving cell’s Cell ID• The radio link Timing Advance• Detected neighbor cells and Rx levels

• Server approximates the UE location

T3T2

T1

Provides neighbor cell information and triangulates the UE location

Serving eNB

Cell 3Cell 2

E-SMLC

Measures OTDOAof each neighbor relative to the serving cell

Provides assistance datafor faster/more reliable GPS fix

Provides GPS location Serving eNB

E-SMLC

�d

D

Cell ID locates the UE to the cell size and shape

Timing Advance gives the UE’s approximate distance from the serving eNB

Detected neigbors and their relative signal levels approximate where in the arch the UE is

Neighbor eNB

Serving eNB

Neighbor eNB

E-SMLC

Estimates the UE location based on the measurement reports

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2

3


Accuracy expectations of the LTE positioning techniques

1m 3 10 50 100 300 1km 3km 10km

Availability

Accuracy

remote

rural

sub-urban

city

in-door

A-GNSS

Satellitepositioning

Primary Location Determination method

Supplementary Location Determination method

95% <150m

67% <50m

OTDOA

Hybridization /E-CID

Cell ID based methods

WiFi

GLONASS/GALILEO


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A-GPS Fallback Combined

Less than 3 sites detected; OTDOA fails,E-Cell-ID used.

3 or more sites detected; OTDOA works � 3 sites detected

~70% of cases;OTDOA works

Positioning accuracy

Assume • 67% probability for GPS fix• 80% probability for GPS

location error < 50m• 100% probability for GPS

position error < 150m

P(50m)

P(150m)

73%54%

85%67%

Performance of the fall-back methods, city environment

78%

95%

The A-GPS performance is compromised in urban/indoor environments

• WLAN a good fall-back technique for indoors case, not used in this slide.

The performance of the fallback methods heavily depending on the deployment

• Cell sizes• Deployment of OTDOA• Usage of OTDOA hearability aids


Summary

• 3GPP Release 9 standardized positioning techniques for LTE• A-GNSS (A-GPS) as the primary method• Enhanced Cell-ID and OTDOA as fall-back methods

• A-GPS performance very good when GPS fix successful• Urban/Indoor challenging for A-GPS

• Fall-back techniques’ performance heavily deployment dependent• Cell sizes• Usage of OTDOA and its hearabilty enhancements• Base station accuracy (antenna locations, transmit timings)• WLAN a good candidate for enhanced indoor positioning performance


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9 © Nokia Siemens Networks

Thank You! Questions ?


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Documents

Performance of 3GPP Rel-9 LTE positioning methods Nokia