PSAP Operations Guide for Wireless 9-1-1

PSAP Operations Guide for Wireless 9-1-1

July 2005

PSAP Operations Guide for Wireless 9-1-1 ii

Notice © 2005 Intrado Inc., Longmont, Colorado, USA - All rights reserved. Intrado, triangle beacon design, Informed Response, and the logo forms of the foregoing, are trademarks and/or service marks of Intrado Inc. in the United States, other countries, or both and may be registered therein.

This documentation may not be altered, copied, distributed, published, displayed, or reproduced in whole or in part without Intrado's prior written consent except as otherwise provided in writing. Any authorized use, in whole or in part, must contain the following statement: © 2005 Intrado Inc. All rights reserved. Trademark Information All trademarks are properties of their respective owners. It is the policy of Intrado to improve products and services as new technology, software, hardware, and firmware become available. Intrado, therefore, reserves the right to change specifications without prior notice.

PSAP Operations Guide for Wireless 9-1-1 iii

Table of Contents INTRODUCTION............................................................................................................. 1 A BRIEF HISTORY OF WIRELESS E9-1-1 ................................................................ 2

GETTING READY FOR PHASE I.......................................................................................... 5 GETTING READY FOR PHASE II ........................................................................................ 7

PHASE I OVERVIEW..................................................................................................... 8 PHASE I TECHNOLOGY OVERVIEW................................................................................... 9 PHASE I—WHAT THE DISPATCHER SEES ....................................................................... 13

PHASE II TECHNOLOGY OVERVIEW ................................................................... 15 GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS ........................................................ 16 OTHER SOLUTIONS ........................................................................................................ 17 ACCURACY TESTING AND VERIFICATION....................................................................... 17 PHASE II—WHAT THE DISPATCHER SEES...................................................................... 18 LOCATION RE-QUERIES AND MID-CALL UPDATES......................................................... 19

FREQUENTLY ASKED QUESTIONS........................................................................ 20 GLOSSARY..................................................................................................................... 22

PSAP Operations Guide for Wireless 9-1-1 1

IINNTTRROODDUUCCTTIIOONN Authorities involved in 9-1-1 find themselves facing ever changing and new technologies giving people the ability to access emergency services by multiple means. This document provides information about wireless Enhanced 9-1-1 (E9-1-1) history, technology, mandates, and implementation activities. Intrado Inc. has been involved in developing processes, identifying technical methodologies, and deploying wireless E9-1-1 since 1996. This document represents the collective knowledge of individuals who have faced similar challenges. Intrado provides this information to help you deploy, train, and understand wireless E9-1-1.


AA BBRRIIEEFF HHIISSTTOORRYY OOFF WWIIRREELLEESSSS EE99--11--11 Earlier solutions for wireless E9-1-1 implementation were developed based on the call flow model that E9-1-1 systems have been operating under since the 1970s. Alternative solutions have been developed that minimize the economic impact of adding wireless to the existing E9-1-1 infrastructure. There are a few core methods used by Intrado and others for connecting wireless calls through the Mobile Switching Center (MSC) to the Public Safety Answering Point (PSAP) and moving the call-back number and cell site information either directly to the PSAP or to the Automatic Location Identification (ALI) database for subsequent display at the PSAP. Those methods are discussed later in this document.

Wireline E9-1-1 infrastructure has been implemented in the United States since the 1970s, using primarily analog technology. The wireline version of E9-1-1 uses a single telephone number—Automatic Number Identification (ANI)—to route the call and retrieve the data that provides PSAPs with information about who is calling and where the caller is located. With the advent of wireless telecommunications—and its inherent mobility—the "who" and "where" were no longer associated with the caller’s telephone number. The challenge in integrating wireless and wireline technologies is to provide the PSAPs with essentially the same information to which they are accustomed to receiving from the wireline system.

After several years of handling wireless 9-1-1 calls without any associated data, the public safety community—embodied by several national professional organizations (NENA, APCO, and NASNA1)—joined together in 1994 to officially lobby the Federal Communications Commission (FCC) for service parity between existing wireline E9-1-1 systems and wireless services. The Commission requested that wireless subscribers be provided the same level of service available to wireline subscribers. The result of the Commission’s efforts was the opening of a Notice of Proposed Rule Making (NPRM) in FCC Docket # 94-102.

The magnitude of the technical challenge became evident to the communications industry and 9-1-1 professionals as soon as the NPRM was released for comment. The result of these comments led the FCC to release a Report and Order (R&O) that identified two phases of implementation, occurring over a specified time period, to allow for appropriate technological adjustments to bring wireless service up to par with wireline service.

Phase I requires that the calling party’s mobile telephone number and location of the cell site and sector from which the 9-1-1 call originated be delivered to the PSAP. The logic was that the caller’s number would be used to call back in the event the connection was lost; and the location of the originating cell site and sector would provide a level of location information that would allow delivery of the 9-1-1 call to the appropriate PSAP.

1 NENA: National Emergency Number Association; APCO: Associated Public Safety Communications Officers; and NASNA: National Association of State Nine-One-One Administrators.


Phase II requires that the mobile telephone number and location of the caller, within a specified accuracy margin, be delivered to the call taker in the form of earth coordinates (latitude and longitude). This phase requires the incorporation of new components into the wireless infrastructure to determine and provide the specific location information.

When the FCC’s R&O was released, there were a limited number of location technologies being used and tested in connection with the Department of Defense and other research activities. Since that time, wireless use across the country has exploded. In some markets, customers have actually chosen to discard their wired telephone service in exchange for the much more portable and sometimes more cost-effective wireless service. The growth can be seen in these numbers:

Year Number of Subscribers

1988 2 million

1993 16 million

1999 70 million

2002 134 million

2003 155 million

The first proposed wireless 9-1-1 solution used Call-path Associated Signaling (CAS). CAS allowed for the caller’s wireless telephone number to be routed along with the voice call to the PSAP. Both the Telecommunications Industry Association (TIA) and NENA supported this solution. This method followed the existing wireline model: the caller’s number (ANI) would arrive with the voice and be displayed for the call taker. In a wireline E9-1-1 system, the ANI not only identifies the caller’s telephone number but is used to retrieve the ALI from the 9-1-1 database. Given that wireless callers are often on the move and there is no static relationship between their location and their callback number, a modification was needed to route the call within the existing wireline infrastructure. The response to this need in a CAS solution was the creation of a pseudo-ANI (pANI) for each sector of each Phase I cell site. The pANI, like a telephone number (ANI), is a ten-digit number that cannot be assigned to a wireless subscriber’s telephone and is only used to provide routing and location information to the wireless E9-1-1 system. Because the cell site, unlike the wireless telephone, is at a fixed location, the pANI assigned to a sector of a cell site can be used to route the call to the correct PSAP and retrieve the ALI from the 9-1-1 database.

A second issue related to ANI delivery was that some wireline systems used a type of shorthand—or numbering plan digit (NPD)—for identifying the area code of the calling party. The trunk group delivering each ANI to the selective router represented a specific area code, or numbering plan area (NPA). In addition, there was a limitation of four NPAs that any specific selective router could manage. In the wireless environment, a cell


phone user whose telephone has a New York area code can make a wireless call in California as easily as local users who may need to make 9-1-1 calls. This means that any number of NPAs had to be supported by a selective router. In order for the CAS solution to work, network-signaling capabilities had to be enhanced to allow both the caller’s callback number and a pANI in the delivery of a wireless 9-1-1 call to a PSAP. In effect, the proposed solution more than doubled the number of digits—from eight to twenty—that would be forwarded to the PSAP. This change created other issues within the existing 9-1-1 systems, such as network capabilities, call set-up time, and limitations of PSAP customer premise equipment (CPE). As a result, additional solutions emerged for deployment of Wireless E9-1-1, including Non-Call-path Associated Signaling (NCAS), Hybrid CAS, and NCAS with WID solutions.


GGEETTTTIINNGG RREEAADDYY FFOORR WWIIRREELLEESSSS This section highlights the steps necessary to become ready at the PSAP level to accept wireless enhanced 9-1-1 calls and to have all the necessary data elements available to the public safety professionals who are responsible for answering the caller’s request for service.

GETTING READY FOR PHASE I The PSAP must address administrative, operational, and technical considerations to prepare for wireless E9-1-1.

For public safety related to Phase I, the FCC requires that the PSAP:

Is capable of receiving and using Phase I data Has a mechanism in place to pay their costs associated with the service Requests the service in writing from the wireless carrier.

When all of these requirements are met, the wireless carrier has six months—or 180 days—to either provide the service or have the consensus of the 9-1-1 authority for a later deadline.

Deployment of Phase I service also requires that the PSAP coordinate with the Local Exchange Carrier (LEC) and/or 9-1-1 service provider to do the following:

Assure and/or modify the ALI format to allow the wireless caller’s information to be displayed correctly on the PSAP’s ALI screen

Request an Emergency Services Number (ESN) for wireless E9-1-1 calls Request (from ALI provider) that appropriate MSAGs be built for wireless records Determine the PSAP’s SR to PSAP trunking configuration for wireless calls.

Some considerations for this decision are as follows: - Does the PSAP want both wireless and wireline calls to be transported

across the same trunks? If the answer is yes, are there currently enough trunks? OR

- Does the PSAP want dedicated wireline and wireless trunks? If the answer is yes, does the PSAP’s CPE need to be upgraded to accommodate this configuration?

The following table shows the deployment process and roles and responsibilities during the Phase I deployment process.


Item PSAP LEC WSP 3rd Party

Send request for wireless E9-1-1 service (RFS) to the wireless service provider (WSP). X

Notify Intrado (3rd-party provider) to proceed with deployment. X

Gather specific PSAP information. X X

Verify PSAP boundary. X X

Provide MSC and cell site data to 3rd-party vendor. X

Plot wireless carrier cell sites on the verified PSAP boundary map. X

Perform network analysis/recommend an appropriate number of MSC to SR trunks. X

Order and install required MSC to SR trunks. X X

Connect MSC to MPC/GMLC (initial market deployment) X X

Request/provide routing numbers. X X X

Discuss PSAP ALI screen display format. X X X

Determine default and alternate routing requirements at the MSC. X X X

Determine sector routing and PSAP cell sector location description. X X

Determine whether new ESNs will be used for wireless calls. X X

Ensure MSAGs are built to support wireless deployment. X X

Provision ALI database records. X

Provision E9-1-1 selective router. X X

Configure and provision MPC/GMLC. X

Incorporate E9-1-1 translations into wireless carrier’s MSC. X

Verify network, selective router, ALI database and MPC/GMLC readiness. X

Determine testing schedule. X X X

Provide all routing and test documentation. X

Conduct pre-deployment testing of all network components. X X

Conduct pre-production and 9-1-1 live call testing at all cell sectors. X X X

Declare 9-1-1 cutover a success! X X X X


GETTING READY FOR PHASE II The considerations that have to be made for Phase II wireless E9-1-1 service are similar to the considerations for Phase I.

For public safety related to Phase II, the FCC requires the following from the PSAP:

Is capable of receiving, displaying, and using the horizontal latitude/longitude

coordinates Has a mechanism in place to pay their costs associated with the service Requests the service in writing from the wireless carrier

When all of these requirements are met, the wireless carrier has six months—or 180 days—to either provide the service or have the consensus of the 9-1-1 authority for a later deadline.

Note: Many of the carriers have been granted waivers in reference to the six-month deadline. Please check the FCC website at www.fcc.gov/911 to verify the new date requirements.

As in Phase II, the PSAP must coordinate with the LEC and/or 9-1-1 service providers to ensure the following:

The LEC and/or database provider has the proper interface in place to the 9-1-1 database. The current interfaces are E2, E2 Plus, or enhanced PAM.

The ALI format is modified to allow the display of the latitude/longitude coordinates.

The 9-1-1 CPE can manually re-query the ALI database to request updates for the location of the Phase II caller.

If the PSAP has chosen to interface with a mapping system and/or computer-aided dispatch (CAD) system, the PSAP must make sure the interface and data format from the 9-1-1 CPE to these systems meets all of the requirements to display and use the Phase II data properly.

If Intrado has not verified your PSAP boundaries within the previous six months, Intrado will contact you to verify the wireless jurisdictional boundary.


PPHHAASSEE II OOVVEERRVVIIEEWW This section starts with a high-level understanding of wireless Phase 0 and provides a discussion of the technical solutions employed in wireless E9-1-1. A number of Phase 1 and Phase 2 solutions are discussed and illustrated with appropriate diagrams to provide you with an overview of wireless 9-1-1. To develop an understanding of wireless 9-1-1, it is extremely helpful to understand the wireline environment from which it evolved.

The Wireline E9-1-1 Call Environment E9-1-1 networks components operate together in order to deliver a 9-1-1 call—including caller data—to a PSAP. In the wireline E9-1-1 environment, a 9-1-1 call is placed from a wireline telephone and sent to the local central office that serves that specific telephone. The central office recognizes the call as 9-1-1 and forwards the call to a specialized switch, referred to as a selective router. The selective router routes both the voice and the caller’s telephone number (ANI) to the appropriate PSAP. The PSAP’s Customer Premise Equipment (CPE) uses the ANI to retrieve the caller’s Automatic Location Information (ALI) by querying the ALI database.

PSAP's ALI

Workstation

Telephone

ANI Controller

ALI Controller

PSAPLandline Phone Central Office

911Selective Router

ANI (TN) ANI (TN)

PSAP's ALI

AN

I (TN

)

Loca

tion

Info

rmat

ion

= Voice Path

= Data Path

What is Phase 0? Wireless Phase 0 is the delivery of the wireless 9-1-1 call to a PSAP without the display of any caller information. In most cases, Phase 0 calls are delivered through the public telephone switch network to the PSAP. However, in some limited situations, Phase 0 calls may be delivered through the 9-1-1 trunks to the PSAP. If the call is delivered on an administrative line and the PSAP subscribes to caller ID services through its LEC, the telephone number of the wireless device may be delivered to the 9-1-1 call taker.


PHASE I TECHNOLOGY OVERVIEW This section discusses the wireline and wireless E9-1-1 network configurations and common Phase 1 solutions.

The Wireless E9-1-1 Call Environment There are several Wireless E9-1-1 solutions currently deployed that provide the required voice and data to a PSAP from the WSP’s network. These solutions can be grouped into three basic categories: Call-path Associated Signaling (CAS), which uses an expanded call signaling path through the E9-1-1 network; Non-Call-path Associated Signaling (NCAS), which uses digital out-of-band signaling over a separate data path; and Hybrid-CAS (HCAS), which uses an expanded call signaling path to the Selective Router and out of band signaling from Selective Router to ALI to deliver the unique call data. In all of these solutions the WSP must connect a voice and signaling path from its MSC to the E9-1-1 selective router. This transports the caller’s voice to the PSAP. The MSC is a switch that serves as the entry point for wireless calls received by multiple cell site sectors into the public switched telephone network (PSTN) and performs a role that is parallel to that of the end office in the wireline environment.

Non Call-Path Associated Signaling (NCAS) Solution The NCAS solution uses a Mobile Positioning Center (MPC) or Gateway Mobile Location Center (GMLC) that provides routing of all necessary data to both the MSC and the ALI database. The call is routed by two (2) separate paths to the PSAP. Voice over the voice path and ALI information over the data links are already in place. The voice call and routing number—called an Emergency Service Routing Key (ESRK)—are delivered to the PSAP through the serving 9-1-1 selective router. The MPC/GMLC dynamically populates the callback number and cell sector location information data for this call into the ALI database record indexed by the ESRK (aka pANI) assigned to the call. When the PSAP receives the voice call, the ESRK retrieves a record containing the call-back number and the cell site location data from the ALI database.

PSAP's ALI

Workstation

Telephone

ANI Controller

ALI Controller

PSAPMSC

911Selective Router

ESRK ESRK

PSAP's ALI

ESR

K

Location InfoC

allback #

MPC

= Voice Path

= Data Path

911(Send)

Cell Site

OR

RE

Q/IA

M in

Mes

sage

(MS

C, C

ell S

ite a

nd S

ecto

r ID

s,C

allb

ack

#)

OR

RE

Q R

esponse/IA

M O

ut(E

SR

K)

ALI Push(ESRK, Loc Info, Callback #)

Acknowledgment

NCAS Network Configuration


Call-Path Associated Signaling (CAS) Solution The CAS solution delivers the caller’s voice and call-back number to the PSAP through the voice portion of the network. The MSC forwards the call-back number along with the voice using a routing number called an Emergency Services Routing Digit (ESRD) that mimics the ANI for the purposes of 9-1-1 call routing. To accommodate the transmission of both the ESRD and callback number, CAS requires that 20 digits of data be transmitted to the PSAP along with the voice. The ESRD is pre-provisioned in the 9-1-1 selective router and ALI database, similarly to a wireline telephone record, to appropriately route the call based on the cell sector that received it. When the call is received at the PSAP, the ESRD serves as a lookup key into the database to retrieve static cell sector location information.

While the use of the CAS solution is a viable solution for Phase I, this solution does not have a migration path from Phase I to Phase II. CAS does not accommodate the additional data—latitude and longitude—required to identify actual caller location (nor will it in the foreseeable future). With a CAS solution, the SR, SR to PSAP trunks, and PSAP CPE must be capable of receiving 20 digits (accommodating call-back number and the routing number) through the voice call path. Often, the implementation of CAS requires upgrades to selective routers, trunking between selective routers and PSAPs, and upgrades to PSAP CPE to accommodate the extra ANI digits.

PSAP's ALI

Workstation

Telephone

ANI Controller

ALI Controller

PSAPMSC

911Selective Router

ESRD (pANI)+ Callback #

PSAP's ALI

AN

I (TN

) LocationInfo

911(Send)

Cell Site


= Voice Path

= Data Path

Call Path Associated Signaling (CAS)


Hybrid CAS Hybrid CAS (HCAS) is a combination of CAS and NCAS call delivery. HCAS delivers the call from the wireless carrier’s network to the 9-1-1 selective router in CAS (full 20 digits). At the router, the ESRD and callback number is sent to the ALI database where ALI creates a temporary record, assigning a routing “key” to the record (the digits used for the “key” vary by HCAS solution). The ESRD is used to look up the static location information in ALI. This static location information is copied into the temporary record along with the callback number. The SR then uses the key to deliver voice, over the voice path, to the PSAP. The PSAP’s CPE then uses the “key” to query ALI and obtain the callback and location information for the call.

This delivery solution is dependent upon the Local Exchange Carrier’s (LEC) or 9-1-1 service provider’s ability to implement the HCAS software solution within its network (on both the Selective Router and ALI) and is not available in all areas.

PSAP's ALI

Workstation

Telephone

ANI Controller

ALI Controller

PSAPMSC

911Selective Router


PSAP's ALI

Key

Location Info(inc X

,Y)

& Callback #

911(Send)

Cell Site

Key(Callback #or Call ID)

= Voice Path

= Data Path

Key

ESRD & Callback #

Phase I HCAS Call Flow


NCAS Solution with WID Device The functionality of the selective router can be altered to accept twenty digits along the voice path, but if the PSAP on the other end cannot accept the twenty digits, the router must strip off half of those digits to complete the voice call to the PSAP. In some cases, selective router functionality has been altered through either software or hardware upgrades to perform this function. In other cases, a device generically referred to as a wireless integration device (WID) is added into the network to perform this specialized function. A WID can be used to accept 20 digits conveyed from the MSC; the 20 digits are composed of the routing number and the caller’s 10-digit number. The WID converts a 10-digit ESRD to an 8-digit ESRD that is then passed with the voice call to the selective router. The WID device routes both the ESRD and the call-back number to the ALI database where the ALI record is dynamically updated with the call-back number.

When the PSAP receives the voice call, the PSAP uses the ESRD to query for the ALI record. In some cases—mainly related to the type of mobile switch used by the carrier—wireless carriers can use this solution to affect only Phase I wireless deployment. Specific technical details must be identified very early during deployment to ensure that the appropriate equipment is available. WIDs can be deployed either by wireless carriers or by LECs to resolve technical systems interface issues if necessary.

Similar to the NCAS solution described above, provisioning the ALI record supporting this solution assumes that the caller’s call-back number may be dynamically inserted into the ALI record at the time of the call. Information about the cell sector receiving the call is built into an ALI record with the appropriate ESRD number as its lookup key.

PSAP's ALI

Workstation

Telephone

ANI Controller

ALI Controller

PSAPMSC

911Selective Router

ES

RD

(pAN

I)&

Cal

lbac

k #

PSAP's ALI

ESR

D

Location Info(inc X

,Y)

& Callback #

911(Send)

Cell Site

ESRD (pANI)

ESRD & Callback #

= Voice Path

= Data Path

WID

ESRD

(pANI)

WID Solution NCAS


Summary Each of the technology solutions described above represents a viable method to provide the Phase I E9-1-1 data to the PSAP, taking into account the needs and capabilities of the WSP, the LEC network, and the PSAP. The selection of the technological solution used to deliver the required Phase I data to the PSAP is dependent upon existing E9-1-1 infrastructure, the technological capabilities of the WSP and the economic realities that PSAPs face.

PHASE I—WHAT THE DISPATCHER SEES The information displayed at the PSAP to the dispatcher may vary somewhat from the traditional ALI screens, depending on the solution the WSP uses to deploy wireless E9-1-1. Below are examples of the various call technologies. Please remember that individual PSAP equipment may vary from these examples.

NCAS Call Display In the NCAS delivery, the call is delivered over two paths. The voice over 9-1-1 trunks and the data are retrieved over the ALI circuit or path, just as wireline calls are sent. The ALI record is updated for every call with dynamic information. The ANI or call-back number is displayed along with the identification or description of the cell site. The routing number or ESRK is displayed in the LOC field. The NENA company ID for the wireless carrier whose network is handling the call will also be displayed.

The figure below is an example of an NCAS call display.

720-111-9600 ESN: 787WIRELESS CARRIER NAME123 MAIN ST – N SECTORBOULDER PSAP MOBL/WRLS WIRELESS CARRIER IDLOC= 303 511-2345BOULDER CO WIRELESS - VERIFYVERIFYVERIFY

callback number(Dynamic Data in Red)

cell sector location description

routing digit (ESRK/pANI)

NCAS Call Display Example


CAS Call Display In the CAS delivery, the call is delivered over a single path. The ANI or call-back number is displayed along with the identification or description of the cell site. The routing number or ESRD is displayed in the pilot number field. The NENA company ID for the wireless carrier whose network is handling the call will also be displayed.

The figure below is an example of a CAS call display.

720-111-9600 303 511-2345 ESN: 787W IRELESS CARRIER NAME123 MAIN STBOULDER PSAP MOBL W IRELESS CARRIER IDLOC = N SectorBOULDER CO W IRELESS - VERIFYVERIFYVERIFY

callback number routing digit (ESRD/pAN I)

cell sector tower address

cell sector location description

CAS Call Display Example

HCAS Call Display The HCAS call is delivered using a combination of NCAS and CAS. From the 9-1-1 service provider’s selective router, the call is delivered to the PSAP over two paths. The voice on the regular 9-1-1 trunks and the data are retrieved over the ALI circuit or path, just as wireline calls are sent. The ALI record is updated for every call with dynamic information. The ANI or call-back number is displayed along with the identification or description of the cell site. The routing number or ESRD is displayed in the pilot number field. The NENA company ID for the wireless carrier, whose network is handling the call, will also be displayed.

The figure below is an example of an HCAS call display.

720-111-9600 303 511-2345 E S N : 787W IR E LE S S C A R R IE R N A M E123 M A IN S T – N S E C T O RB O U LD E R P S A P M O BL/W R LS W IR E LE S S C A R R IER IDB O U LD E R C O W IR E LE S S - V E R IF YV E R IF YV E R IF Y

callb ack nu m b er rou ting d igit (E S R D /pA N I)

cell secto r location descrip tion

Phase I – HCAS Call Display Example


PPHHAASSEE IIII TTEECCHHNNOOLLOOGGYY OOVVEERRVVIIEEWW Wireless Phase II requires that the specific location of the caller be delivered to the PSAP in the form of earth coordinates, (latitude/longitude, or x,y). This phase requires the incorporation of a positioning determining entity (PDE) into the wireless infrastructure to determine and provide location information.

The FCC defines two types of PDE technology— network-based and handset-based. Network-based means that the components needed to determine location are embedded into the wireless E9-1-1 network, such as at the MSC and/or cell sites. Handset-based means that some of the location technology is embedded into the wireless handset, such as a Geographical Positioning System (GPS) chip or software modifications.

The FCC adopted accuracy and reliability requirements for ALI as part of its rules for wireless carrier E9-1-1 service in CC Docket No. 94-102, Revision of the Commission’s Rules to Ensure Compatibility with Enhanced 911 Emergency Calling Systems. Those rules were adopted in 1996 and revised in the Third Report and Order in that docket (released October 6, 1999). The revised rules set the following accuracy and reliability requirements for E9-1-1 Phase II operations:

For network-based solutions: 100 meters for 67 percent of calls; 300 meters for 95 percent of calls;

For handset-based solutions: 50 meters for 67 percent of calls; 150 meters for 95 percent of calls.

Phase-in schedules for Phase II are incorporated in Section 20.18(g) of the Commission’s Rules (47 C.F.R. § 20.18(g)

PSAP's ALI

Workstation

Telephone

ANI Controller

ALI Controller

PSAP

MSC

911Selective Router

(ESNE)

ESRK ESRK

PSAP's ALI(ESME)

ESR

K

Location Info (inc X,Y

)C

allback #

MPC

911(Send)

Cell Site

OR

REQ

MSC

, Cel

l, C

allb

ack

#

orreq (response)- ESRK

ESPOSREQ (query for location-initial or update)

esposreq (Phase I initialand/or

Phase 2 location

CRDB

POSRTEREQ (X,Y)

posrtereq (P

SAP)PDE

E12

GPOSREQ

(request for location)

gposreq (Phase 2

location

= Voice Path

= Data Path

E2

E3

ANSI NCAS Phase II Wireless 9-1-1 Network Diagram


GLOBAL SYSTEM FOR MOBILE COMMUNICATIONS To provide a higher level of functionality for wireless services, there are some WSPs that are moving to the next generation of technology called Global System for Mobile Communications (GSM). The network components, functionality, and terminology related to wireless 9-1-1 varies. The network configuration diagram for GSM (below) identifies these differences. In many cases the positioning determining functionality for this technology is embedded in both the wireless handset and the carrier’s network. Because of complexities and the recent introduction of GSM in North America, the FCC has provided a phased approach for accuracy and time to deployment. This information is located on the FCC website at www.fcc.gov/911.

PSAP's ALI

Workstation

Telephone

ANI Controller

ALI Controller

PSAP

MSC

911Selective Router

(ESNE)

ESRK ESRK

PSAP's ALI(ESME)

ESR

K

Location Info (inc X,Y)C

allback #

GMLC

911(Send)

Cell Site

ISU

P Lo

opar

ound

Rou

ting

Info

rmat

ion

ESPOSREQ (query forlocation-

initial or update)


Phase 2 location

BSCSMLC

BTS

LsLg

Loca

tion

Info

rmat

ion

= Voice Path

= Data Path

GSM MAP NCAS Phase II


OTHER SOLUTIONS There are other solutions, including HCAS for Phase II, that are not discussed in detail in this document, but if you become aware that either a wireless carrier or LEC are deploying these alternatives, you should become familiar with their network configurations and functionality to understand how they operate. The following diagram is a generic Phase II HCAS call flow.

PSAP's ALI

Workstation

Telephone

ANI Controller

ALI Controller

PSAP

MSC

911Selective Router

(ESNE)

ESRDCallback #

Key(Callback #or Call ID

PSAP's ALI(ESME)Ke

y

Location Info(inc X

,Y)

Callback #

MPC

911(Send)

Cell Site

OR

RE

Q/IA

M In

orreq (response)/IAM

Out

ESPOSREQ (query forlocation-

initial or update)


Phase 2 location

PDE

E12

GPOSREQ

(request for location)

gposreq (Phase 2

location

ESRD

Callback #

ESN

= Voice Path

= Data Path

ANSI HCAS Phase II

ACCURACY TESTING AND VERIFICATION. In April 2000, the FCC released the document Guidelines for Testing and Verifying the Accuracy of Wireless E911 Location Systems (OET Bulletin No. 71). This document was prepared as a guideline to provide assistance in determining whether PDEs comply with the above accuracy standards set by the FCC. It addresses general principles related to default fallback, uncompleted calls, and timing and also provides recommendations on testing and verification methods, including empirical and predictive testing.

The Emergency Service Interconnection Forum (ESIF) Technical Report ATIS-05000, High Level Requirements for Accuracy Testing Methodologies (May 11, 2004) provides a common frame of reference that individual stakeholders can use to validate the accuracy methodology of 911 location technologies. The document provides a set of minimum requirements to which individual testing methodologies should comply.


PHASE II CALL ROUTING Phase II solutions provide two alternative methods for determining the PSAP to which a wireless 9-1-1 call will be routed. If x,y coordinates of the wireless phone placing the emergency call are available within the requisite routing interval, those coordinates can be used to determine the appropriate routing of the call. If the coordinates are not available in time to route the call, the cell site/sector routing established for Phase I will be used.

PHASE II—WHAT THE DISPATCHER SEES The information displayed at the PSAP to the calltaker may vary somewhat from the traditional ALI screens, depending on the solution the WSP uses to deploy wireless E9-1-1. Below are examples of the various call technologies. Please remember that individual PSAP equipment and ALI formats may vary from these examples.

In Phase II, as in Phase I, the ANI or call-back number is displayed along with the identification or description of the cell site. In addition, the latitude and longitude are delivered and can be plotted on the PSAP’s selected mapping system. Uncertainty and Confidence are measures of the predicted accuracy of the delivered coordinate location information and are not always available to the PSAP. The ESRD is typically displayed in the LOC field. The NENA company ID for the wireless carrier, whose network is handling the call, will also be displayed.

During the Phase I deployment, the PSAP’s wireless jurisdictional boundaries are established. Phase II uses those boundaries to identify the appropriate PSAP to receive the 9-1-1 call.

The figure below is an example of a typical Phase II data display.

(Dynamic Data in Red)

720-111-9600 ESN: 787WIRELESS CARRIER NAME123 MAIN ST - NE-104.548407 +39.356910COF 45BOULDER PSAP WPHII WIRELESS CARRIER IDLOC= 303 511-2345BOULDER CO WIRELESS – VERIFY

VERIFYVERIFY

callback number

cell sector text location description(Phase I type information)

routing digit (ESRK/pANI)

Longitude (X) and latitude (Y)

Uncertainty (meters) COP 90 Confidence factor (%)

Phase II Data Elements


LOCATION RE-QUERIES AND MID-CALL UPDATES Location re-queries and mid-call updates are dependant on many factors. The PSAP will need the capability to request a manual re-query in the following events:

The caller’s latitude/longitude (x,y) is unavailable at the time the call is delivered to the PSAP.

To request a more accurate x,y if the uncertainty or confidence factor was at the high end of the acceptable range.

The PSAP needs an updated location for the caller.


FFRREEQQUUEENNTTLLYY AASSKKEEDD QQUUEESSTTIIOONNSS Q What is the difference between static and dynamic data in ALI records?

Static data is the data that is built into the ALI record and remains unchanged during the 9-1-1-call process. Dynamic data is the information that is inserted into ALI records at the time of a 9-1-1 call. Examples of dynamic data are Callback Number, Cell Site Address and Location Coordinates (Latitude/Longitude). Dynamic data is generally inserted into ALI by the means of an MPC, GMLC, gateway, a CAMA conversion device—such as Proctor®, CML, WID, Cell Trace™—or a selective router with added functionality.

Q Where will the callback number be displayed in the ALI record? The host ALI provider, along with the PSAP, determines the placement of the callback number. Considerations include ALI display format and capabilities and available NENA-standard data fields in the ALI database. The callback number location is ultimately determined by the LEC and/or PSAP but is typically placed in the Loc field, the RCF field, or the TN field.

Q What is a cell sector? Cell sites—or base stations—usually have one or more sectors or receiving antennas (one sector is most common in rural areas where maximum coverage is most desired; three or more sectors are common in urban areas where simultaneous call volume is more of an issue). Each sector is a separate antenna—or an array of antennas—that emits and retrieves radio frequency (RF) signals. Sectors of multiple-sector sites typically send and receive RF signals from a particular direction and have a coverage area shaped roughly like a slice of pie. In the case of Phase I, identifying the directional orientation of the sector that is handling a 9-1-1 call can help to identify caller location.

Q How does the cell site recognize the cell phone callback number and pass it to the MSC? When a cell phone is used to call 9-1-1, it sends out a radio frequency (RF) signal, which is picked up or received by an antenna on a cell site. The cell site receives the radio frequency signal and relays it to the MSC. The RF signal includes the electronic serial number (ESN), which is a 32-bit number that is coded into the wireless phone, and the callback number of the phone. The combination of the ESN and callback number uniquely identifies the account number of the wireless phone subscriber. Due to upcoming ESN number exhaust, manufacturers will be coding wireless phones with a machine equipment identifier (MEID). MEIDs are 56 bits, 14 hexadecimal digits, and are much larger numbers than ESNs.

Q Will PSAPs need to spend money to upgrade their CPE for Phase I? No. If your PSAP is already enhanced, Phase I service does not require any changes to your CPE.


Q Can PSAPs receive Phase I if they are not enhanced? No. Since current Phase I technologies require ANI delivery and ALI retrieval, the PSAP must be part of an E9-1-1 wireline network. (According to the FCC's Report & Order in Docket No. 94-102, the wireless carrier is not obligated to deliver Phase I service unless the requesting PSAP is able to make use of the data elements to be provided.)

Q What is the difference between an ESRD and an ESRK? The emergency service routing digit (ESRD) is a routing number or group of numbers assigned per cell site/sector. The ALI record for an ESRD contains a static address field that defines the cell sector location to the PSAP and may be dynamically updated with the callback number at the time of the call. In a CAS environment, there is no update required in the ALI record because the callback number arrives with the voice as part of a 20-digit ANI.

The emergency service routing key (ESRK) is also a routing number or group of numbers, but the numbers are assigned on a per PSAP basis. The ALI record for an ESRK may be dynamically updated with the address field and the callback number at the time of the call. The ESRK lends itself to additional field updates for wireless Phase II, where location coordinates will be identified and passed into the 9-1-1 system.

Q Where are the MSCs located? The MSCs are part of the wireless network infrastructure and are located within the wireless carrier’s facilities.

Q Wireless integration devices (WIDs), also known as Proctor boxes or Cell Trace™ boxes, are called CML boxes at Bell South. What are these devices? WIDs are devices that handle a 20-digit signal and convert that signal to send it along two separate paths to complete a wireless 9-1-1 call. CML Technologies is one of the manufacturers who make one of these WID devices. Proctor and Associates is another manufacturer of a WID device. Qwest uses the product name Cell Trace when providing WID service for wireless 9-1-1.


GGLLOOSSSSAARRYY This section provides the definitions and explanations of the terms, acronyms, and abbreviations used within this document and the 9-1-1 Industry.

Term Definition

ALI Automatic Location Identification. A feature of E9-1-1 service that displays the name and address associated with the number of the phone used to dial 9-1-1. A database managed by a database provider.

ALI Database Host computer system that stores ALI records.

Alternate Routing A feature of Enhanced 9-1-1. Allows E9-1-1 calls to be routed to a designated alternate location if the 9-1-1 system malfunctions, or the primary PSAP is unable to receive and process 9-1-1 calls.

ANI Automatic Number Identification. A feature that displays, at the answering point, the number of the phone from which the 9-1-1 call was placed. In the wireless environment, ANI is the display of the Mobile Directory Number (MDN).

ANSI American National Standards Institute

CAS Call-Path Associated Signaling. A term that describes data transmission or signaling that occurs on the same channel as voice communication. In the 9-1-1 environment, CAS is associated with the transmission of the wireless caller’s mobile directory number (MDN) along the same channel as the caller’s voice.

CBN Callback number. On a wireless E9-1-1 call this is the Mobile Directory Number (MDN) that the PSAP would use to re-contact or callback the caller.

CDMA Code Division Multiple Access as defined in IS-95. When a communication channel is shared by spread spectrum transmitted each with a different spreading code for the purpose of achieving multiple access. Spread spectrum is a technique to spread a signal over a frequency band that is larger than the signal being sent in order to gain interference immunity. This is one of several ways wireless or cellular devices function.

Cell Basic geographic unit assigned to a fixed location cellular transmitting and receiving station.

Cell Face See Cell Sector.

Cell Sector Location Information

Data that indicates the cell sector from which a 9-1-1 call has been placed.

Cell Sector The geographical area served by a cell site is divided into coverage areas of one or more sectors (receiving antennas). 1 sector (Omni) is common in rural areas where maximum coverage is most desired; 3 or more sectors are common in urban areas where call volume is more of an issue.

Cell Sector Number

The unique numerical identification of a cell sector.

Cell Site A radio transceiver base station that acts as a point of entry for calls from wireless devices into the wireless carrier’s telecommunications network.

CLEC Competitive Local Exchange Carrier.


Term Definition

CLLI Common Language Location Identifier. A Bellcore Standard code used to identify a central office (CO) through the use of an 11-character code.

CMRS Commercial Mobile Radio Service. This is the formal FCC classification of wireless carriers.

CO – Central Office

A telephone-switching center that contains the equipment to provide phone service to users in a particular geographic area. A CO may serve more than one prefix, or more than one CO located in the same building. Also known as End Office, Control Office.

CPE Customer Premise Equipment. Phone or terminal equipment located on the customer’s premises. This equipment may be owned or provided by the customer or a telephone company.

CRDB Coordinate Routing Database.

Default Routing A feature of Enhanced 9-1-1. Default routing occurs when a 9-1-1 call cannot be selectively routed because the ANI signal is garbled or not available to the tandem switch.

Directional Antenna

An antenna or array of antenna designed to concentrate radio signal in a particular area.

E2 Messaging protocol for transferal of ALI data for Phase II to send the x, y, confidence, uncertainty, cell sector information.

ELT English Language Translation. A database table in MS that provides the names of the emergency service agencies associated with the Administrative ESN. Both Intrado data analysts and the MSAG coordinator are responsible for maintaining and updating ELTs.

EMF Enhanced Multi Frequency. A voice path signaling protocol that allows the transmission of up to 20 digits per call using Multi Frequency tones.

Enhanced 9-1-1 (E9-1-1)

Includes ANI and ALI features that display name, address or cell sector info, and TN of 9-1-1 caller.

End Office The telephone-switching center that initiates a 9-1-1 call. Also known as CO.

ENP Emergency Number Professional.

ESCO Emergency Service Central Office Number. The information delivered to the PSAP when there is an ANI failure between the end office and the 9-1-1 Control Office. When ANI is not available, the 9-1-1 call is default routed and the ANI display at the PSAP will be "911-0TTT" (or 911-TTTT) with TTT identifying the trunk group between the end office and the selective router and therefore, the end office.

ESN Emergency Service Number. A three to five digit alphanumeric code that represents an emergency service zone. This number is used by selective router to route E9-1-1 call to a particular PSAP.

ESPOSREQ Request to the MPC or GMLC by the ESME for location information for the wireless caller

esposreq MPC/GMLC response to the ESME containing the wireless caller’s location data

ESRD Emergency Services Routing Digit. A 10-digit routable, but not necessarily


Term Definition

dialable, number that is used for routing on a per origination cell sector basis.

ESRK 10 digit routable, but not necessarily dialable, number that is used not only for routing but also as a correlator, or key, for the mating of data that is provided to a PSAP by different paths, such as via the voice path and ALI data path. In daily use, the term ESRK is used to distinguish operational environments where the “routing” digits are assigned on a per destination PSAP basis as opposed to a per origination cell sector basis (which is the strict technical definition of an ESRD).

Federal Communications Commission

(FCC) The United States agency, which is charged with licensing and regulation of the wireless industry.

FCC NPRM FCC Notice of Proposed Rule Making (NPRM) issued 10/94 -ensures compatibility with E9-1-1 calling systems and is to be implemented in phases: - Phase 0—The delivery of a voice call from a wireless device to a

PSAP. - Phase .5—Delivers the caller’s voice and call back number. - Phase I—Delivers the caller's voice, call back number, and cell site

sector information. - Phase II—Delivers Phase I info plus the Latitude and Longitude of the

caller (x, y) FOA First Office Application. The initial installation of an application into a

customer site.

Geo-code The assignment of a geographic coordinate to a non-location value (e.g., street address to lat./long coordinate)

GIS Geographic Information System

GMLC Gateway Mobile Location Center

GPOSREQ MPC’s request for the wireless caller’s X,Y from the PDE

gposreq PDE’s response to the MPC containing the wireless caller’s X,Y

GPS Global Positioning System

GSM Global System for Mobile Communications. The standard digital phone service offered in Europe and Japan. Some carriers in the United States are also deploying this standard as well.

HCAS Hybrid Call-path Associated Signaling

ILEC Incumbent Local Exchange Carrier

IAM Initial Address Message - ISUP

ISDN Integrated Services Digital Network. A hierarchy of digital switching and transmission systems synchronized so that all digital elements speak the same language at the same speed. ISDN provides simultaneous voice and digital transmission capabilities. A digital interface providing multiple channels for simultaneous functions between the network and CPE.

LEC Local Exchange Carrier.

LNP Local Number Portability.


Term Definition

MDN Mobile Directory Number. A 10-digit directory number used to call a wireless phone.

MIN Mobile Identification Number. Key identification number assigned by the cellular carrier to a cellular phone, paired with the electronic serial number both numbers are verified for legitimate wireless call making.

MPC Mobile Position Center. The MPC serves as the entity that retrieves, forwards, stores, and controls position data within the location network. The MPC receives and stores the position estimation for subsequent retrieval.

MS Mobile Station

MSC Mobile Switching Center. A switch that provides stored program control for wireless call processing. Identifies the switching office that processes the cellular call to the Public Switch Telephone Network (PSTN). SCC uses the term MSC as per TR45.2, but “MTSO” and “MSO” also describe a mobile switching center.

MSO Mobile Switching Office. See MSC.

MTSO Mobile Telephone Switching Office. See MSC.

NCAS Non Call-Path Associated Signaling. A term that describes data transmission or signaling that occurs on a separate channel than that which transmits a voice communication. In the 9-1-1 environment, NCAS refers to a wireless solution set that employs a signal control point (SCP) within a wireless carrier network. The SCP has a software application installed to provide dynamic update of several data fields during the course of a 9-1-1 call event. The NCAS solution set permits PSAPs to receive ANI and ALI information relating to a wireless voice call via separate data channels, thus permitting the continued use of CAMA lines. The solution set requires that routing numbers (ESRD/K) be built following the relationship of trunk capacity to each PSAP being deployed.

OREQ or ORREQ Origination Request message sent to the MPC by the MSC

pALI Pseudo ALI (Automatic Location Identification). In the Wireless 9-1-1 application, this is the ALI for the pANI. pANI is used to route the call to the appropriate PSAP, not a call-back number to reconnect with the caller.

pANI Pseudo ANI (Automatic Number Identification). In the Wireless 9-1-1 application, this is the ANI for the pANI. pANI is used to route the call to the appropriate PSAP, not a call-back number to reconnect with the caller.

PDE Position Determining Entity. The PDE determines the precise position or geographic location of a wireless terminal when the MS starts a call or while the MS is engaged in a call. Each PDE supports one or more position determining technologies.

POSRTEREQ MPC’s request from CRDB for a number associated with a PSAP for routing purposes.’ The MPC provides the wireless caller’s X,Y to the CRDB.

posrtereq CRDB response to the MPC containing a number associated with a PSAP for the purposes of routing the wireless caller’s emergency call.

PS/ALI Private Switch/Automatic Location Information: The process of providing ALI information for access lines located within a PBX environment. In this process, the private switch must provide data to the 9-1-1 system to identify the locations of 9-1-1 calls placed through the switch.


Term Definition

PSAP Public Safety Answering Point. A facility equipped and staffed to receive 9-1-1 calls. A Primary PSAP receives the calls directly. If the call is relayed or transferred, the next receiving PSAP is designated a Secondary PSAP.

PSTN Public Switched Telephone Network. The network of equipment, lines, and controls assembled to establish communication paths between calling and called parties in N. America. The phone system, including the Network.

Routing Number A number used to facilitate the routing and delivery of a wireless 911 call. Routing numbers are assigned both in quantity and configuration, dependent upon the solution set employed. See also ESRD and ESRK.

Rehome The process of relocating the records that serves a specific geographic area from one switch to another. Rehoming typically affects MSCs and Selective Routers.

RF Radio Frequency.

SALI Stand-alone ALI. An ALI database, which is maintained locally at the PSAP on-premise or at a telephone company’s central or regional office.

SCP Service Control Point. A centralized database system used for, among other things, wireless E9-1-1 service applications. It specifies the routing of 9-1-1 calls from the cell site to the PSAP. The SCP contains special software and data that includes all relevant cell site location and cell sector identifiers. SCPs contain centralized network databases for providing enhanced services. The SCP accepts queries from a STP and returns the requested information to the originator of the query. They provide the core database and call processing functions on which telecommunications services are based. A remote database within the SS7 network that supplies the translation and routing data needed to deliver advanced network services. Identifies cell sites sending 9-1-1 calls to the 9-1-1 network. Part of the SS7 network that determines where the call should be connected according to the digits dialed – usually a database with routing and control information. Also referred to as a Signal Control Point.

Secondary PSAP A PSAP that only receives emergency calls from the 9-1-1 network as a result of a transfer. 9-1-1 calls are not routed to secondary PSAPs.

SR or Selective Routing

Selective Router. A switch that provides the feature in which 9-1-1 calls from a central office area that is served by more than one PSAP are electronically routed to the proper PSAP. The combination of the Routing ESN and the customer location information accomplish this.

SR / ALI Selective Router Automatic Location Information. An SCC proprietary product that allows compatible selective routers to query the ALI database for routing instructions.

STP Signal Transfer Point. The packet switch in the Common Channel Interoffice Signaling (CCIS) system.

TDMA Time Division Multiple Access. A digital (usually radio) system that allows a number of users to use the same system by being dynamically assigned a particular timeslot on request.

TDOA Time Difference of Arrival. A method of location determination using the time differences at which the radio signal arrives at multiple sites or antennas in a network.


Term Definition

TN Telephone Number. Unique combination of ten digits that identifies the equipment used to place and receive calls.

Trunk A network communication path connecting two switching systems. A Central Office circuit terminating in the telephone equipment on the customer’s premises. A circuit between CO and the PSAP.

WID Wireless Integration Device. A device that performs a protocol conversion function to allow for transport of wireless data into the 9-1-1 system without modifying existing selective routers or PSAP CPE.

WIN Wireless Intelligent Network. Term used by cellular carriers in the wireless industry. SS7 based, Standardization Activity (IS-53), MIN Based value added services.

Wireless A set of radio-based telecommunications services including cellular, paging, PCS and other mobile radio services. A technology that combines the use of radio frequency and hard wired telephone networks to allow voice and/or data communications from, to and between devices that are, may, or may not be hard wired to the public switched telephone network.

WSP Wireless Service Provider.

PSAP Operations Guide for Wireless 9-1-1

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Transcript of PSAP Operations Guide for Wireless 9-1-1