E-911 Enhancement Solutions

(1)

Indoor Wireless Accuracy:

E-911 Enhancement Solutions

Impacts on In-Building Distributed Antenna Systems

Ski C ill

Skip Crilly

(2)

Topics

• _{What is E-911?}

_{What is E 911?}

• _{How are E-911 calls located?}

d

d l

• _{FCC-mandated location accuracies}

• _{FCC-led activities to improve accuracy}

• Issues with indoor location accuracy

• New technologies that improve indoor

New technologies that improve indoor

position accuracy

(3)

Indoor Subscribers

• Wireless devices are the number one means of communications

today

• 70 percent of voice calls and 80 percent of data sessions occur

indoors

M t l b ildi d i ( ) d di t d t ( )

• Most large buildings and campuses require (a) dedicated system(s)

to ensure ubiquity of:

– Cellular

– Public safety

– WiFi services

• Thousands of distributed antenna system (DAS) nodes and

repeaters are installed at hundreds of higher education institutions in the United States

(E-911 LOCATION technology rarely evaluated!) (E 911 LOCATION technology rarely evaluated!)

(4)

Mobile Subscribers Dominate System

• _{According to FCC, about 455,000 of the 650,000 911}

calls made every day are from wireless phones

wireless e911 calls landline e911 calls

• _{Many homes and apartments no longer use landlines}

_{Many homes and apartments no longer use landlines}

(5)

How is a wireless 911 call located?

Present Solutions to E911 Positioning Present Solutions to E911 Positioning

• GPS satellite signals are received and reported to the network

• CDMA downlink signals from cell sites are measured by the calling device and reported by the device to the network

GSM li k i l f th E 911 d i d b

• GSM uplink signals from the E-911 device are measured by, and reported, using location measurement units (LMUs)

• Serving cell site identification is reported to the network, as a g p , backup report

• Each operator’s cellular network provides a 911 call location fi t th bli f t i i t (PSAP)

(6)

E-911 Positioning Systems are Different From

Commercial Location Based Services Applications

Smarter phones have more commercial app capability but E-911 positioning has to work with all devices

Commercial Location

Engines

but E 911 positioning has to work with all devices

Engines Google, Apple… Measurements E 911 t Measurements

commercial applications _{E-911 system}

commercial applications

(7)

History of E-911

• E-911 = Enhanced 911

• 1994 - FCC docket opened in (94-102)

• 1996- within five years, requires accuracy of 125m RMSy , q y

• 1999- Separate handset and network-based rules adopted

– 50m CDMA, (x2 GSM) for 67 percent of calls50m CDMA, (x2 GSM) for 67 percent of calls

– 150m CDMA, (x2 GSM) for 95 percent of calls

• 2012 – FCC indoor location accuracy initiativey

(8)

History of E-911

Continued

• FCC opens new docket in 2007 (07-114) to update rules

J 2011 b d h d h h II l

Continued

• January 2011- broad changes made to the phase II rules

• Accuracy is to be measured at PSAP or county boundary level

• New rules are being phased in over the rest of the decade such that all service providers will be required to provide 50 meter accuracy 67 percent of the time, and 150 meter y p ,

accuracy 90 percent of the time, in 90 percent of the counties nationwide

• Indoor location accuracy investigation

(9)

911 Calls

Need Indoor Location

• No FCC requirement exists for indoor testing. Dormitories, parking garages, office areas, commons, class rooms, arenas, stadiums and other GPS - denied venues can “fit” into the ten stadiums and other GPS - denied venues can fit into the ten percent exclusion zone of the 150m 90 percent (to be 95

percent) mandate

• The current FCC requirements will leave a university campus vulnerable to large position errors in the places likely to be in need of assistance

(10)

FCC Activities:

Indoor Location Accuracy

• The FCC has given a CSRIC working group the goal of investigating new technologies, and reporting indoor E-911 location accuracyg , p g y

• ~40 experts from industry and carriers are in the CSRIC working group

• An indoor test-bed is underway at several locations in northern California y participants:

– Qualcomm/Verizon – AFLT, MCS, A-GPS

– NextNav – 900 MHz LMS

– Boeing – Iridium

– Polaris – RF Fingerprinting

• Future: WiFi beacons and others – for future discussion

CSRIC i i i li bili i bili il

(11)

A 911 caller’s device receives many signals

Not all signals are used for E-911

Glonass

Iridium Glonass

LMU = Location measurement

Green = Currently used for E-911

GPS GPS

LMU = Location measurement unit

CDMA

900 MHz FCC LMS

FCC Location & Monitoring Service

CDMA GSM 911 WiFi CDMA WCDMA LTE LMU LMU

(12)

GSM and CDMA Systems

Use different positioning methodsp g

• GSM service providers (e.g. AT&T) use uplink measurements of cell

phone transmissions to determine E-911 position solution

– U-TDOA is the standard technique: cell phone signals are measured at BTS (True Position, Inc.)

– Location measurement units (LMU’s) measure relative uplink signal delays

• CDMA service providers (e.g. Verizon) use downlink measurements of

base stations and GPS satellite transmissions to determine E-911 solutions

– A-GPS is part of the 911 solution. A-GPS = Assisted GPS

– AFLT is the terrestrial technique: BTS signals are measured at the cell phone (Qualcomm Inc ) AFLT advanced forward link trilateration phone (Qualcomm, Inc.). AFLT = advanced forward link trilateration

– Use CDMA Pilot signals in CDMA carrier for measurements

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The Indoor E-911 Positioning Issue

• Issue: Indoor E-911 calls often cannot be located accurately, because:

because:

– GPS satellite signals may be blocked in urban canyons

– GPS satellite signals do not penetrate many building structuresg p y g

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Issue : Position accuracy degrades

due to in-building distributed antenna system

due to in building distributed antenna system

Repeater antenna 911 Base-station RF over fiber to another building to another building 911

Where is the 911 call originating from?

(15)

Compounding Problems

• Repeaters

– Signals re-promulgated are delayed by several microseconds, distortingSignals re promulgated are delayed by several microseconds, distorting

measurements by thousands of feet.

– BTS signals used for positioning require much lower SINR than those

needed for communication, therefore some non repeated signals are heard which can result in a pathologic condition: Some signals are delayed, others not.

• DAS Environments

– Operational paradigm forbids use of measurements from BTS signals that

go through fiber. (Not Line of Sight and velocity only 0.6 c).

Operational paradigm forbids measurements from BTS signals that are

– Operational paradigm forbids measurements from BTS signals that are

ambiguous due to simulcasting.

– Geometric techniques, e.g. signal strength measurements, are

compromised due to inability of tools to model small or oddly shaped DAS compromised due to inability of tools to model small or oddly shaped DAS coverage footprints.

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A Repeater’s Effect on

Position Measurements

Real Distance

Repeater’s 3 microseconds of delay => ~1000 yards of measurement error.

Repeater

Real Distance

Perceived Distance based on Perceived Distance based on measured time of arrival through repeater

O-DAS and I-DAS deployments have similar effects on perceived subscriber location due to d l d b fib ti d h i f th l

delays caused by fiber routing and physics of the glass

DAS Simulcasting to Multiple Buildings

Measurements from BTS Disqualified; Subscribers in

Building 5/6 _q _;

Building 1 & 2 Indistinguishable

Building 1 Building 2

Building 3/4

BTS / HE BTS / HE

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Are there existing solutions to these problems?

Yes

.

Yes

.

• Add additional network elements

U dditi l t ffi t f t k t l li t

– Use additional traffic sectors of a network to localize coverage to

particular buildings

– Add location measurement units in GSM/WCDMA networks – Both of these solutions add complexity to the network.

• Add additional signals using beacons

– The additional signals are unique to a venue

– A CDMA co-pilot beacon (CPB) is a technology that has existing

network compatibility and is cost-effective

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Co-Pilot Beacon Deployment

for Repeater Covered Venue

Co-Pilot Beacon

Beacon coverage footprint is small…. If you can hear me, you must be near me!

The CDMA network’s Base Station Almanac uses the beacon location and contains a building-footprint size metric.

(20)

Co-Pilot Beacons provide

additional distance references

Co-Pilot Beacon PN1 PN2 GPS BTS or off-air repeater feeds a distributed antenna system T1 T2 GPS T1

DAS coverage indoors Macro outdoors PN5 PN4 PN3 T4 T3 Device requiring position info T4

(21)

CPB signals are summed into a distributed

antenna system

• How to sum CPB signals into traffic channels

I j t CPB i l t l t th h t it

– Inject CPB signal at low power at the host units

– Inject CPB signal at low power before PA at DAS remote unit

– Inject CPB signal into DAS server antennaj g

Or, sum digital signal if digital media

Directional coupler Host i ( ) Remote i ( ) Fiber or other media

Head end N From BTS or repeater unit(s) unit(s) or coax N 21

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Some aspects of

Co-Pilot Beacons

Co Pilot Beacons

• CPBs are not proprietary technologyCPBs are not proprietary technology

• CPBs are currently supplied by multiple equipment vendors

• No change is required to the existing E-911 control plane interface standards for operation

• Current/future handset and smart-phone CDMA chipsets are compatible without modification

compatible without modification

• CPB locations are known and entered for accurate positioning, managed as a network element

• Periodic surveys are not required to ensure beacon location integrity

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McCarran Airport

Situation Goal and Solution

Situation, Goal, and Solution

• Situation: After the McCarran Airport DAS is installed in concourses A and B, the PSAP will not be able to

adequately differentiate between 911 calls made from concourse A or concourse B, due to the simul-casting concourse A or concourse B, due to the simul casting of a sector to both concourses

• Goal : A first responder needs to have increased

• Solution: Install co-pilot beacons based on the DAS

Goal : A first responder needs to have increased

confidence which concourse the call is originating from

Solution: Install co pilot beacons based on the DAS design and the design goal

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DAS Deployed without Co-Pilot Beacons

(100 Test calls)

X

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Typical Metropolitan Airport

w/ DAS Deployed

1000 test calls Objective is 95% of fixes within 150 25% of the fixes were outside the

50% of the fixes were between

meters

Test location X were outside the

1/4 mile radius 150 m & 1/4 mile

radius

X

25% of the fixes 25% of the fixes were inside the 150 m radius

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The position uncertainty is caused by the

simulcasting of the BTS into the DAS

g

BTS/HE BTS/HE

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DAS Deployed With Beacons

(100 test points)

(

p

)

X

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Typical Metropolitan Airport after Co-Pilot

Beacon Installation

Objective of 95% of fixes within 150 Test location X meters is achieved

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Some Issues when adding beacons

to indoor DAS infrastructure

• It is possible that the wireless network will not be able to

id h PN d d d b h b d

provide the new PN codes needed by the beacons, due to code exhaustion

• The wireless network needs its databases to reflect theThe wireless network needs its databases to reflect the beacons’ locations

• Solution : A multi-PN co-pilot beacon

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Multi-PN CDMA Co-Pilot Beacon

Description

• Multiple PNs are transmitted simultaneously on multiple existing macro 1xRTT channels

existing macro 1xRTT channels

• Beacon pilot PN offsets are chosen to match nearby macro cell-site PN offsets, rather than use “new” PNs

• Beacon transmit delays (taus) are adjusted to match expected delays from macro sites to fix location

• The solution brings the macro network’s positioning capability

• The solution brings the macro network s positioning capability into the venue

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A Multi-PN Co-Pilot Beacon

Multi-PN Co-Pilot Beacon Tau_PN1 = T1 Tau PN2 = T2 Beacon Tau_PN2 T2 Tau_PN3 = T3 Tau_PN4 = T4 Tau_PN5 = T4 Et PN1 PN2 GPS BTS or off-air repeater Etc. PN1 T2 Benefits:

-No BTS database entries

T1

T2

DAS space inside Macro space outside No BTS database entries

-No BSA database entries -Moveable fix using CPB taus -Adjust taus for best accuracy

PN4 PN3

T3

p

PN5

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Multi-PN CDMA Co-Pilot Beacon

Benefits

• PNs do not have to be dedicated to pilot beaconsp

– No PN exhaustion

• Base station almanac entries are not required for multi-PN CPB transmitters

• Neighbor lists generally do not have to change

Low risk of neighbor list exhaustion

– Low risk of neighbor list exhaustion

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Babson College Multi-PN Beacon E911 Tests

Pre-Fixes Indoor DAS On/Off– Beacons Off Pre-Fixes Indoor DAS On/Off– Beacons Off

Fixes with the DAS ON

-Off-air Repeater located in bldg. other side of campus

Fixes with the DAS OFF Fixes with the DAS OFF

5 km

High percentage of outliers

(34)

Babson College Multi-PN Beacon E911 Tests

Pre-fixes Indoor; DAS On ; Beacons On Pre-fixes Indoor; DAS On ; Beacons On

l f

One outlier of ~40 E911 tests

Additional successful Multi-PN Tests: -Rockingham MallRockingham Mall

-CSI lab/screen room

E911 test location

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Review

• Position determination for E-911/public safety is more problematic indoors than outdoors

• Coverage and capacity enhancements adversely impact location accuracy

• Smart phone apps do not currently help the public safety E-911 system

• Exceptions to the E-911 FCC mandate are sufficient today to account for in-building positioning errors

• When indoor subscribers have sufficient reference points, location accuracies are much improved

(36)

Advice for a Safer Venue

• If you are deploying a DAS and/or repeater solutions for coverage be concerned about the impact on E-911

coverage, be concerned about the impact on E 911 positioning: A COMPLETED CALL IS NOT ENOUGH

• Augmentation equipment is considered generally available by WSPs. Request its deployment as part of the DAS solution

and test it

h b h

• Engage systems integrators with subject matter expertise who are willing to work with the customer, WSPs, PSAPs to

engineer in-building location solutionsg g

YOUR VENUE WILL BE SAFER WHEN FIRST RESPONDERS KNOW WHERE TO GO!

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Thank You!

Questions?

William J. (Skip) Crilly Jr.

CTO

Cellular Specialties, Inc. (603) 606-7782

[email protected]