U.S. patent application number 14/834832 was filed with the patent office on 2015-12-17 for enhanced e911 network access for a call center using session initiation protocol (sip) messaging.
The applicant listed for this patent is TeleCommunication Systems, Inc.. Invention is credited to Jonathan Croy, Richard Dickinson, Gordon John Hines.
Application Number | 20150365811 14/834832 |
Document ID | / |
Family ID | 39303624 |
Filed Date | 2015-12-17 |
United States Patent
Application |
20150365811 |
Kind Code |
A1 |
Dickinson; Richard ; et
al. |
December 17, 2015 |
Enhanced E911 Network Access for a Call Center Using Session
Initiation Protocol (SIP) Messaging
Abstract
A switched emergency call (e.g., a 911 call, an alarm company
call) forwarded by a telematics call center is converted into a
session initiation protocol (SIP) packetized phone call at the call
center, and routed over an IP network, for presentation to an
emergency services gateway, which connects to a selective router
via dedicated circuits, gaining full access to the Enhanced 911
network. This provides a PSAP receiving a call from a telematics
call center or other call center with all features available in an
Enhanced 911 network, e.g., callback number of the 911 caller, and
location of the 911 caller. Location of the caller is provided
using a VoIP positioning center (VPC), queried from the call
center. In this way, the switched emergency call is converted into
a SIP packetized phone call and routed without further passage
through the public switched telephone network (PSTN).
Inventors: |
Dickinson; Richard;
(Seattle, WA) ; Hines; Gordon John; (Kirkland,
WA) ; Croy; Jonathan; (Seattle, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TeleCommunication Systems, Inc. |
Annapolis |
MD |
US |
|
|
Family ID: |
39303624 |
Appl. No.: |
14/834832 |
Filed: |
August 25, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14176557 |
Feb 10, 2014 |
9125039 |
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14834832 |
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13758721 |
Feb 4, 2013 |
8682286 |
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14176557 |
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13437538 |
Apr 2, 2012 |
8369825 |
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13758721 |
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12588332 |
Oct 13, 2009 |
8150364 |
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13437538 |
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11581454 |
Oct 17, 2006 |
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12588332 |
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11150343 |
Jun 13, 2005 |
7903791 |
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11581454 |
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10739292 |
Dec 19, 2003 |
6940950 |
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11150343 |
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Current U.S.
Class: |
370/338 |
Current CPC
Class: |
H04M 2242/30 20130101;
H04M 3/58 20130101; H04M 7/1205 20130101; H04M 11/04 20130101; H04L
65/1006 20130101; H04W 4/90 20180201; H04M 3/42059 20130101; H04M
7/006 20130101; H04W 4/44 20180201; G01S 19/01 20130101; H04M
3/5116 20130101; H04L 65/1069 20130101; H04M 11/00 20130101; H04W
4/029 20180201 |
International
Class: |
H04W 4/22 20060101
H04W004/22; H04M 3/51 20060101 H04M003/51; G01S 19/01 20060101
G01S019/01; H04M 7/00 20060101 H04M007/00; H04W 4/04 20060101
H04W004/04; H04L 29/06 20060101 H04L029/06; H04M 7/12 20060101
H04M007/12 |
Claims
1-12. (canceled)
13. A method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP),
comprising: converting into a packetized Internet Protocol (IP)
communication, at a call server, an incoming communication
initiated on a wireless device from a given location; injecting
location information into said converted packetized Internet
Protocol (IP) communication; routing said converted packetized IP
communication to a PSAP selected based on said given location; and
routing a return packetized IP communication from said PSAP to said
wireless device.
14. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, further comprising: injecting a callback
number associated with said wireless device, into said converted
packetized Internet Protocol (IP) communication.
15. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, wherein: said communication is a PSTN phone
call.
16. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, wherein: said communication is an Internet
Protocol (IP) communication.
17. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, wherein: said communication is a Voice over
Internet Protocol (VoIP) call.
18. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, wherein: said routing is based on an
emergency services routing key (ESRK) determined based on said
given location.
19. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, further comprising: injecting into said
converted packetized IP communication, as a callback address
associated with said wireless device, an address of a VoIP
positioning center.
20. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, wherein: said location information of said
wireless device is determined using a global positioning system
(GPS) device within said wireless device.
21. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 20, wherein: said GPS device is
vehicle-based.
22. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, wherein: said IP communication is routed to
a designated session initiation protocol (SIP) Uniform Resource
Identifier (URI) associated with said PSAP.
23. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, wherein: said call server is associated with
a wireless telematics call center.
24. The method of passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP)
according to claim 13, wherein: said call server is associated with
an alarm monitoring service.
25. A system for passing an incoming wireless device communication
to a call center, to a Public Safety Answering Point (PSAP),
comprising: means for converting into a packetized Internet
Protocol (IP) communication, at a call server, an incoming
communication initiated on a wireless device from a given location;
means for injecting location information into said converted
packetized Internet Protocol (IP) communication; means for routing
said converted packetized IP communication to a PSAP selected based
on said given location; and means for routing a return packetized
IP communication from said PSAP to said wireless device.
26. The system for passing an incoming wireless device
communication to a call center, to a Public Safety Answering Point
(PSAP) according to claim 25, further comprising: means for
injecting a callback number associated with said wireless device,
into said converted packetized Internet Protocol (IP)
communication.
27. The system for passing an incoming wireless device
communication to a call center, to a Public Safety Answering Point
(PSAP) according to claim 25, wherein: said communication is a PSTN
phone call.
28. The system for passing an incoming wireless device
communication to a call center, to a Public Safety Answering Point
(PSAP) according to claim 25, wherein: said communication is an
Internet Protocol (IP) communication.
29. The system for passing an incoming wireless device
communication to a call center, to a Public Safety Answering Point
(PSAP) according to claim 25, wherein: said communication is a
Voice over Internet Protocol (VoIP) call.
30. The system for passing an incoming wireless device
communication to a call center, to a Public Safety Answering Point
(PSAP) according to claim 25, wherein: said routing is based on an
emergency services routing key (ESRK) determined based on said
given location.
31. The system for passing an incoming wireless device
communication to a call center, to a Public Safety Answering Point
(PSAP) according to claim 25, further comprising: means for
injecting into said converted packetized IP communication, as a
callback address associated with said wireless device, an address
of a VoIP positioning center.
32. The system for passing an incoming wireless device
communication to a call center, to a Public Safety Answering Point
(PSAP) according to claim 25, wherein: said location information of
said wireless device is determined using a vehicle-based global
positioning system (GPS) device.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to E9-1-1 emergency phone
calls. More particularly, it relates to emergency E9-1-1 calls
using Voice Over Internet Protocol (VoIP), originating from
centralized call centers.
[0003] 2. Background of the Related Art
[0004] 911 is a phone number legislated into law as a designated
universal emergency phone number used by callers to access
emergency response services. Enhanced 911 (E911) is defined by the
transmission of callback number and location information to the
relevant public safety answering point (PSAP). A PSAP is the
endpoint of an emergency services call. PSAPs are responsible for
answering emergency services calls. E911 may be implemented for
landline, VoIP, and/or mobile devices. Some Public Safety Access
Points (PSAPs) are not enhanced, and thus do not receive the
callback or location information from any phone, landline or
mobile.
[0005] Many cars built today include a telematics system. The word
"telematics", in its broadest sense, relates to the combination of
computers and wireless telecommunications technologies. More
recently, the term "telematics" has evolved to refer to automobile
systems that combine global positioning satellite (GPS) tracking
and other wireless communications for automatic roadside assistance
and remote diagnostics. General Motors Corp. first popularized
automotive telematics with its OnStar.TM. system. Mercedes-Benz
offers a similar system called TeleAid.TM.. The use of the word
"telematics" throughout the current specification is intended to
refer to the later definition of more recent recognition, i.e., to
mean automotive telematics.
[0006] Many new vehicles are equipped with wireless-based
telematics units providing services controlled by voice commands.
One successful telematics system is available from OnStar Corp.
(www.onstar.com). According to OnStar, OnStar brings together
emergency service providers, wireless telephone, and satellite
technologies to help protect a driver, and keep them connected on
the road.
[0007] As part of the telematics system, a telematics unit
including a cellular telephone circuit is located within the
vehicle, and powered by the vehicle's battery. Telematics units
were originally analog-only, but have migrated to
analog/digital-ready, and finally to dual-mode analog/digital.
Dual-mode analog/digital telematics units operate on both the
analog and digital wireless networks.
[0008] With a suitable subscription for the use of a telematics
operations center such as OnStar, a driver or passenger in a
vehicle including a telematics unit has access to a voice-activated
calling feature in their vehicle, just in case their hand-held cell
phone is lost, forgotten or has a low battery. They can
pre-purchase OnStar Hands-Free Calling minutes to use on the road.
Such packages are typically billed to a credit card they keep on
file with OnStar. They can order minutes packages by pushing the
phone or white-dot button at any time.
[0009] Conventional telematics units are also capable of providing
location information to a requesting wireless network, using a
Global Positioning Satellite (GPS) mounted in the vehicle, or using
other location technology within the wireless network. When a
vehicle occupant pushes a given button in the vehicle, essentially
calling the telematics operations center, the action initiates the
location-determining technology which then transmits vehicle
location to the telematics operations center. Moreover, if their
air bag deploys, the location of the vehicle can be automatically
reported to the telematics operations center. So it's only when the
button is pushed to contact the telematics operations center, or
when the telematics operations center is responding to an emergency
signal, that the telematics operations center is provided with a
location of the vehicle.
[0010] Today, most telematics companies and more generally alarm
companies monitor signals from customers' car, home or business.
The monitoring is usually centralized in a single location for
customer locations across the country (e.g., a station in Columbus,
Ohio might monitor homes throughout the country for a given
monitoring company. In more global companies, an alarm or other
monitoring company might monitor alarm signals from homes in the
United States from a centralized command center located in Bombay,
India.
[0011] Thus, in today's global economy, when a customer places an
emergency call such as a 911 call (or automated alarm system
emergency call), the call may be routed very far away, and in some
instances half-way across the world. The telematics operator must
then transfer the 911 call to the relevant 911 center (public
safety access point (PSAP)). However, this transfer must take place
over the Public Switched Telephone Network (PSTN) because such
transfer, cannot conventionally be gained to the PSAP's existing
Enhanced 911 (E911) dedicated network. Moreover, note that even the
call related information (e.g., CallerID) provided with the call
would relate to the identity and location of the centralized
telematics center--not to the callback number and certainly not the
location of the customer originally dialing 911.
[0012] FIG. 3 shows conventional relevant systems in an emergency
911 call made via a telematics call center.
[0013] In particular, as shown in FIG. 3, a telematics unit 101
within a car dials 911. The 911 call is serviced by a cell site of
a service provider, which includes a given mobile servicing center
(MSC) 102. The MSC 102 passes the 911 call on to its relevant
telematics call center 104 via the PSTN. The telematics call center
104 may be, e.g., an ONSTAR.TM. call center.
[0014] The operator at the telematics call center 104 that handles
the 911 call of its own subscriber obtains the identity and
location information of the 911 caller. Based on the current
location of the 911 caller, the operator performs a query of a
telematics PSAP database 106 to determine a unique 10-digit phone
number of the proper local PSAP physically responsible for the
location of the 911 caller. The telematics PSAP database 106 is
essentially the equivalent of an Emergency Routing Data Base
(ERDB).
[0015] The operator at the telematics call center 104 then forwards
the 911 caller to the PSAP by dialing its 10-digit phone number via
the public switched telephone network (PSTN) 110.
[0016] Unfortunately, calls that arrive at the PSAP in this manner
do not include call-back number (Automatic Number Identification
(ANI)) and location information (Automatic Location Identification
(ALI)). Moreover, the PSTN telephone 302 at the PSAP 118 is
typically not answered with the same priority as are calls that
originate on its E911 network. In addition, these calls are
typically not recorded or time-stamped by PSAP equipment as are
calls that arrive via the E911 network.
[0017] Trials have been conducted in which a local exchange carrier
(LEC) has permitted access to a selective router for the E911
network via the PSTN. In this trial, the LEC designated a specific
10-digit telephone number for each specific PSAP. A caller has
their emergency call transferred to this 10-digit telephone number,
which is then call-forwarded within the central office to the
selective router, which then forwards the call to the correct PSAP
based upon the digits dialed. However, this solution suffers from
various security issues and has not found favor in the LEC industry
or within the PSAP community.
[0018] Other conventional technology relies on the PSAP having
separate, second set of phone equipment capable of receiving
proprietary data from the telematics center 104. But this solution
would be prohibitively costly to implement nationwide for each
telematics center, not to mention take up valuable space inside a
PSAP center. Thus, the costs and disruption caused by the need for
new hardware makes this a rather undesirable solution.
[0019] There is the need for a simple and effective solution to
providing easy and full access to the Enhanced 911 network of an
emergency services provider (e.g., PSAP) from users of a
centralized call center, e.g. telematics call center, alarm call
center, etc.
SUMMARY OF THE INVENTION
[0020] In accordance with the principles of the present invention,
a method and apparatus for providing a call center with access to
an Enhanced 911 network supporting a public safety answering point
(PSAP) comprises determining a unique PSAP having jurisdictional
responsibility for a physical current location of a caller to the
call center. The caller is forwarded via a switched telephone
network to a VoIP call server. The switched telephone call is
converted into a session initiation protocol (SIP) packetized phone
call at the call center. A VoIP positioning center is queried for
call routing instructions for the SIP packetized phone call. The
SIP packetized phone call is routed to an emergency services
gateway without further passage through the public switched
telephone network (PSTN).
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows an exemplary E911 architecture including E911
network access provided to a telematics call center or other call
center, in accordance with the principles of the present
invention.
[0022] FIG. 2 shows an exemplary call flow tracing an emergency 911
call from a telematics subscriber source to the appropriate PSAP,
in accordance with the principles of the present invention.
[0023] FIG. 3 shows conventional relevant systems in an emergency
911 call made via a telematics call center.
[0024] FIG. 4 depicts another embodiment showing the use of SIP
messaging in lieu of the PSTN for passing an E911 call from a call
center, in accordance with the principles of the present
invention.
[0025] FIG. 5 shows message flow for the embodiment shown in FIG.
4.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0026] In a first embodiment, an emergency call (e.g., 911 call,
alarm company call) forwarded by a telematics call center is routed
over the switched PSTN to a Voice Over Internet Protocol (VoIP)
call server, where the switched call is converted to a packetized
IP call for presentation to an emergency services gateway, gaining
access to the Enhanced 911 network. Location of the caller is
determined by GPS or other technology in the vehicle or in the
wireless network, and is reported to the telematics call center.
The telematics center's call back number is provided to the VoIP
Positioning Center (VPC) via standard call set-up procedures across
the PSTN to the call server, and then from the call server to the
VPC. The caller's location may be provided to the VPC via non-call
path data links to the telematics call center. The VPC will stage
the call-back and location data for subsequent transmission to the
PSAP via the ALI database.
[0027] In a later embodiment, SIP messaging is used in lieu of the
PSTN for passing an E911 call from a call center. If a telematics
call center has VoIP capability, the PSTN may be avoided by routing
telematics E911 calls directly via VoIP between the call center and
the VPC.
[0028] In a last embodiment, wireless emergency services routing
keys (ESRKs) are used to route emergency calls to a telematics call
center over a Voice Over IP (VoIP) network to an enhanced E911
network of a public service access point (PSAP).
[0029] Voice Over IP (VoIP) is a technology that has been developed
as an alternative telephony technology to the conventional
telephony service (e.g. PSTN). VoIP takes advantage of high speed
Internet data packet networks, and is able to provide low cost
telephony services to end users. VoIP technology emulates a phone
call, but instead of using a circuit based system such as the
telephone network, utilizes packetized data transmission techniques
most notably implemented in the Internet.
[0030] VoIP phone calls are routed to a VoIP voice gateway, from
which they are passed on to their destination VoIP device.
Conventional VoIP voice gateways (i.e., soft switches) are
typically located in only a few places across the country. A soft
switch is a programmable network switch that can process the
signaling for all types of packet protocols. Also known as a `media
gateway controller,` `call agent,` or `call server,` such devices
are used by carriers that support converged communications services
by integrating SS7 telephone signaling with packet networks.
Softswitches can support, e.g., IP, DSL, ATM and frame relay.
[0031] Because VoIP is Internet Protocol (IP) based, call related
information such as CallerID type services may not be available or
accurate. A location of a given VoIP device may be provisioned to
be at a given geographic location, or queried from a home location
register (HLR) in a mobile system.
[0032] FIG. 1 shows an exemplary E911 architecture including E911
network access provided to a telematics call center or other call
center, in accordance with the principles of the present
invention.
[0033] The present invention applies the switched telephone
connectivity of the PSTN to route calls to a media gatewayNoIP call
server 112. The switched call is converted into a packetized call
using Internet Protocol (IP), and is routed via the internet to the
ESGW 114 closest to the appropriate selective router for the
destination PSAP. The ESGW converts the packetized IP data back
into traditional TDM, and routes the call to the intended selective
router 116 via dedicated TDM trunks, where it enters the E911
network. A selective router is the node in an emergency services
network that performs enhanced call routing for 911 calls.
[0034] An example will be used to further illustrate the inventive
architecture. In this example, a telematics unit 101 within a car
dials 911. The 911 call is serviced by a cell site of a service
provider, which includes a given mobile servicing center (MSC) 102.
The MSC 102 forwards the 911 call on to its relevant telematics
call center 104 via the PSTN. The telematics call center 104 may
be, e.g., an ONSTAR.TM. call center, and may be located anywhere in
the country or anywhere in the world.
[0035] The operator at the telematics call center 104 that handles
the 911 call of its own subscriber obtains the nature of the call,
as well as the identity and location of the 911 caller. The
identity and location of the 911 call from the subscriber is most
often received by the call center 104 over the open phone line to
their subscriber. Equipment to receive the exact location of the
subscriber is expensive, but necessary only at the centralized
telematics call center. The thousands of PSAPs in the country do
not have the same equipment, as it would be prohibitively
expensive.
[0036] Based on the current location of the 911 caller, the
operator performs a query of a telematics PSAP database 106 to
determine a local PSAP physically responsible for that location, as
well as a unique 10-digit phone number to access the Enhanced 911
network of that PSAP.
[0037] The operator at the telematics call center 104 handling the
911 call forwards the emergency call to a given media gateway/VoIP
call server 112 via the PSTN by dialing the designated 10-digit
number for that PSAP
[0038] To determine the appropriate PSAP and ESGW, the VoIP call
server 112 queries a VoIP positioning center (VPC) 130. Using the
10-digit phone number dialed by the call center operator 104, the
VPC queries the database 134 to determine the corresponding PSAP.
The VPC then assigns an Emergency Services Query Key (ESQK) to the
call and relays this routing key back to the VoIP Call Server
112.
[0039] The VoIP call server 112 passes the 911 emergency call on to
an emergency service gateway (ESGW) 114, which in turn passes the
911 emergency call on to the desired PSAP 118. An ESGW resides in a
VoIP service provider's network, and is responsible for integrating
the session initiation protocol (SIP) network with the emergency
services network (TDM). An ESGW 114 network includes dedicated
voice trunks to selective routers in the Enhanced 911 (E911)
network for any/all PSAPs being served (ideally a national
network). The ESGW 114 routes 911 calls to the appropriate
selective router, based on the ESRN/ESQK it receives.
[0040] The selective router 116 is provisioned with emergency
services query keys (ESQKs) with ALI steering. (The ESQK is a digit
string that uniquely identifies an ongoing emergency services call
and is used to correlate the emergency services call with the
associated data messages. It may also identify an emergency
services zone and may be used to route the call through the
network. The ESQK is similar to an ESRK in wireless E911
networks.)
[0041] A subscriber location database (SLDB) 134 is also
provisioned. Preferably the SLDB 134 is configured so that no
modifications are required to the core conventional existing VoIP
E9-1-1 network. The SLDB 134 is used to relate a Session Initiation
Protocol (SIP) Universal Resource Identifier (URI) or a telephone
number to a PSAP.
[0042] In the given embodiments the SLDB 134 includes a listing of
a series of "subscribers", in which each subscriber is really a
specific PSAP with a designated 1-900-xxx-yyyy phone number. Note
that the phone number does not need to be a 1-900 number as this is
used as an example only. This is also a useful technique for
billing the call center for this service.
[0043] In the disclosed embodiments, the address of this
"subscriber" is the latitude/longitude (lat/lon) of a centroid of
the jurisdiction of the relevant PSAP. Alternatively, in datbases
that use tables in lieu of GIS for routing determination, the
address of the "subscriber" can be any valid address within the
jurisdiction of the PSAP.
[0044] FIG. 2 shows an exemplary call flow tracing an emergency 911
call from a telematics subscriber source to the appropriate PSAP,
in accordance with the principles of the present invention.
[0045] In particular, as shown in FIG. 2, a caller or automated
calling device 101 contacts a local security monitoring company or
roadside assistance operator or similar third party call center
104. As an example shown in step 1, a caller 101 dials 911, which
is serviced through a wireless MSC 102 and passed on to the
relevant telematics call center, e.g., an OnSTAR.TM. call center.
In the given example, the wireless MSC 102 may be part of a
wireless carrier's network, with the 911 call being forwarded to
the relevant telematics call center 104. Alternatively, the MSC 102
may be part of a large wireless network used by the telematics
company itself.
[0046] The 911 call may be placed using an SOS or similar
single-press button located in a car for use in emergency
situations, automatically in the event of an accident, etc.
Alternatively, the phone user may simply dial 911 in a manual cell
phone call from a mobile phone, either integrated into a vehicle or
entirely separate from a vehicle.
[0047] In step 2, a wireless MSC 102 routes the incoming emergency
call to a telematics call center 104 (e.g., an ONSTAR.TM. or
TeleAid.TM. call center). In the given example this routing
includes use of the PSTN 110, though this need not be the case in
all applications.
[0048] The call taker at the call center 104 who receives the 911
call from the caller 101 determines that this is an emergency call
that must be referred to the local 911 PSAP.
[0049] Thus, in step 3, the telematics call taker queries an
existing telematics PSAP database 106 to determine the correct PSAP
to which the call should be routed. Of course, to save time step 3
may be performed simultaneous with, or even prior to, the call
taker's determination that the call from the mobile user 101 is an
emergency call.
[0050] In step 4, a telematics dispatcher dials (could be the same
person and/or equipment as the call taker) a NPA-xxx-yyyy number
designated for the determined PSAP. For instance, the call taker at
the call center 104 then dials 1-900-xxx-yyyy, a designated number
for that PSAP 118, and prepares to conduct a conference call with
the caller 101 and the PSAP 118.
[0051] The call is then routed, via the PSTN 110, to a designated
VoIP call server 112 (alternatively referred to as a media
gateway). The media gateway and the VoIP call server may be two
distinct functions co-located in the same unit, as in the present
embodiment. The media gateway converts TDM to IP. The VoIP call
server routes the resulting IP calls much like a traditional
telephone switch routes a TDM call.
[0052] The VoIP call server 112 receives the ANI (caller ID) of the
call center. The VoIP media gateway 112 reformats the call from
time division multiplex (TDM) or code division multiplexed (CDM)
into session initiation protocol (SIP). The VoIP Call Server
rearranges the dialed digits, putting the DID that was dialed in
step iii (e.g., 1-900-xxx-yyyy) in the FROM field and putting the
ANI of the call center into the Just-in-Time callback number (JIT
CBN) field within the P-Asserted Identity in the SIP Invite.
(Session initiation protocol (SIP) is an IP-based protocol defined
in IETF RFCs 3261 and 2543, the entirety of which are expressly
incorporated herein by reference. SIP is one of two dominant
messaging protocols used by the VoIP industry.
[0053] Importantly, the VoIP Media Gateway/call server 112 converts
the TDM or CDM protocol of the incoming switched network phone call
to packet data using session initiation protocol (SIP), and vice
versa, meaning that packetized VoIP information coming from a
relevant PSAP is converted into a switched connection with the 911
caller, terminated at the VoIP call server 112.
[0054] In step 5, the VoIP call server 112 forwards the 911 call to
the VPC 130 as a VoIP call. The Invite is received by the VPC 130
for call routing instructions.
[0055] The VPC 130 is an application that determines the
appropriate PSAP, based on the location of the 911 caller 101,
returns associated routing instructions to the VoIP network, and
provides the call center's identity and the callback number to the
PSAP through the automatic location identification (ALI). (An ALI
is a database that relates a specific telephone number to an
address. This database accepts a PSAP query with a telephone number
and responds with an address. In the case of an ESQK, the ALI
database steers (redirects) the query to the appropriate VoIP
positioning center and steers the response back to the querying
PSAP).
[0056] A SIP Invite command may be used for the query from the Call
Server 112 to the VPC 130. The disclosed SIP Invite command
preferably includes the following parameters: [0057] a) The "from"
field [0058] =the dialed digits from the call center (NPA-xxx-yyyy)
[0059] b) The "to" field [0060] =911 [0061] c) The JIT CBN field
[0062] =callback number of the call center
[0063] In step 6, the VoIP positioning center 132 queries an ERDB
(SLDB) 134 for call routing instructions based upon the dialed
NPA-xxx-yyyy number. The ERDB 134 relates the dialed number to the
address of that phone number (lat/lon of the PSAP jurisdictional
centroid) and determines the appropriate PSAP to receive the call.
Within the ERDB 134, each phone number corresponds to a different
PSAP.
[0064] In step 7, the ERDB 134 responds to the VPC 130 with the
identity of the appropriate PSAP to serve the caller 101. The VPC
130 assigns an ESQK and emergency services routing number (ESRN) to
the call and stages an ALI record. The ESRN is a 10-digit number
that specifies the selective router to be used to route a call. The
ALI record contains the phone number of the call center 104, based
upon the ANI that accompanied the call. If the call center 104 is
capable of sending the ANI of the actual end user, then this can be
staged in the VPC ALI record.
[0065] Further call processing is otherwise per the conventional
NENA i2 VoIP standard:
[0066] For instance, in step 8, the VoIP positioning center 130
assigns an emergency services query key (ESQK) appropriate to that
PSAP, and stages a record with the call center call back number
(CBN) and call center company ID.
[0067] The VoIP positioning center 130 responds to the VoIP call
server 112 with the ESQK, emergency services routing number (ESRN),
and last routing option (LRO). (The LRO is routing information sent
by the VPC 130 that provides a "last chance" destination for a
call, for example the contingency routing number (CRN) or a routing
number associated with a national call center.
[0068] In step 9, the VoIP call server 112 uses the ESRN to route
the call to the correct emergency services gateway (ESGW) 114.
[0069] The VoIP call server 112 uses the received ESRN to determine
the appropriate ESGW 114 and routes the call appropriately to the
correct emergency services gateway (ESGW) 114. The ESGW 114 uses
the ESRN to determine the appropriate selective router 116. For
simplicity and clarity of description, only one ESGW 114 and one
selective router 116 are pictured in FIG. 2.
[0070] In step 10, the ESGW 114 performs media conversion by
converting the SIP protocol (and vice versa in the opposite
communication direction), and uses the ESRN to route the call to
the correct selective router 116, along with the ESQK.)
[0071] In step 11, the selective router 116 routes the ESQK to the
PSAP 118.
[0072] In step 12, the PSAP 118 queries the automatic location
identification (ALI) database 120 using the ESQK.
[0073] In step 13, the ALI database 120 steers the query to the
VoIP positioning center (VPC) 130, per previously provisioned
steering tables. The VPC 130 responds with a staged record that
includes the callback number (CBN) and call center company ID. In
the preferred embodiments, no latitude/longitude (lat/lon) is sent
in the ALI record, although such data could be forwarded if it is
available.
[0074] In step 14, the ALI database 120 forwards the callback
number (CBN) and call center ID to the requesting PSAP 118.
[0075] FIG. 4 depicts another embodiment showing the use of SIP
messaging in lieu of the PSTN for passing an E911 call from a call
center, in accordance with the principles of the present
invention.
[0076] In particular, according to the embodiment shown in FIG. 4,
in the event that a telematics call center has VoIP capability, the
PSTN 110 may be eschewed by routing the telematics E911 call
directly via VoIP between the call center 104 and the VPC 132.
[0077] As seen in FIG. 4, the PSTN of FIG. 1 is eliminated from the
call flow. In this embodiment, each PSAP is assigned a designated
10-digit number that is provisioned in the telematics PSAP database
106. However, unlike the embodiment of FIG. 1, these 10-digit
numbers need not be dialable via the PSTN. Instead, they can be
assigned by the participating entities without regard to what
numbers may be in use by other parties that use the PSTN. In fact,
they do not necessarily need to be 10-digit numbers at all. Because
they never see the light of day and remain at all times internal to
the telematics vendor and the VPC, these PSAP-identifiers can be
any mutually compatible predetermined format.
[0078] To accomplish this, the telematics call center includes what
would otherwise be included at the telematics call center 104 shown
in FIG. 1, but additionally a session initiation protocol (SIP)
private branch exchange (PBX) or telephone switch 104B.
[0079] FIG. 5 shows message flow for the embodiment shown in FIG.
4.
[0080] In particular, as shown in step 1 of FIG. 5, a cell site
picks up and relays a 911 call made from a wireless subscriber to
the carrier's wireless mobile switching center (MSC) 102.
[0081] In step 2, the wireless MSC 102 passes the wireless 911 call
to the telematics call center 104A, which in this embodiment is
associated with a SIP PBX or voice over Internet protocol (VoIP)
switch 104B. As shown in step 3, upon receipt of the 911 call, the
call taker at the telematics call center 104B accesses the local
telematics PSAP database 106 to determine routing (as otherwise
shown and described with respect to the embodiment of FIGS. 1 and
2).
[0082] In response, the telematics PSAP database 106 provides a
designated PSAP number for that PSAP that need not be a 10-digit
number that is dialable on the PSTN.
[0083] As shown in FIG. 4, the telematics call taker dials the
designated PSAP number and initiates a conference call, or
transfers the call. However, when the telematics call taker dials
the designated PSAP number, the integrated telematics VoIP switch
104B translates the designated PSAP number into a specific SIP
message.
[0084] The VoIP switch initiates a SIP INVITE message in which the
"TO" address is a universal resource indicator (URI) address equal
to a specific mailbox at the VoIP positioning center (VPC) 132
reserved for the PSAP designated by the original designated PSAP
number. The "Just in time Call back Number" (JITCBN) is preferably
provisioned to be the PSTN-dialable phone number of the telematics
call taker at the telematics call center 104A.
[0085] In step 5, the SIP INVITE message is passed to the VoIP
positioning center 132.
[0086] In steps 6-8, the VPC 132 selects an ESQK, ESRN and LRO
appropriate to the PSAP designated in the SIP INVITE message, and
will establish RTP between the SIP switch 104B and the ESGW 114
indicated by the selected ESRN.
[0087] In step 9, a voice path is established via Internet Protocol
(IP) between the VoIP switch 104B and the ESGW 114.
[0088] As is otherwise described herein with respect to the
embodiment of FIGS. 1 and 2, the ESGW 114 performs media conversion
from Internet Protocol (IP) to time division multiplexing
(TDM).
[0089] In step 10, the ESGW 114 routes the call in TDM format to
the designated selective router 116 according to the ESRN or the
ESQK.
[0090] In step 11, the selective router 116 determines the
destination PSAP based upon the ESQK, and routes the call to the
PSAP 118 per existing technology.
[0091] As in the embodiments described above, the VPC 132 stages an
ALI record when it responds to the SIP INVITE. This record consists
of the assigned ESQK, plus the call back number (CBN) received in
the JITCBN field of the SIP INVITE message, plus other data as
available and as desired by the PSAP 118, e.g., NENA ID, lat/lon,
etc.
[0092] In step 12, upon receipt of the call, the PSAP 118 initiates
a standard query to the ALI database 120 per existing
technology.
[0093] In step 13, the ALI database 120 routes that query from the
PSAP 118 to the VPC 132 per otherwise existing technology.
[0094] In step 14, the VPC responds to the ALI query with the
staged record, including a callback number and other data as
desired by the PSAP 118.
[0095] In accordance with the present invention, benefits are
derived by routing 911 calls via the Enhanced E911 network.
Moreover, PSAPs can utilize all available technologies available to
them in an Enhanced E911 network such as CAD, selective transfer,
etc. when responding to a call from a telematics or other call
center.
[0096] The present invention makes possible the transfer of
misrouted or defaulted VoIP calls from a VoIP default call center
to the appropriate PSAP via the Enhanced E911 network. In
conventional systems defaulted calls must be routed via the
PSTN.
[0097] This invention saves taxpayers money by allowing PSAPs to
discontinue designated PSTN lines. This invention also increases
the speed with which emergency services (responders) can be
dispatched and provides recorded documentation of conversations
that are typically available on calls received via the E911
network, but not via the PSTN.
[0098] The present invention has particular relevance for use by
any alarm monitoring company, telematics call center, or emergency
call center that monitors incoming calls. The invention has
significant benefit in the use by automotive roadside assistance
call centers like OnStar.TM., TeleAid, etc.
[0099] While the invention has been described with reference to the
exemplary embodiments thereof, those skilled in the art will be
able to make various modifications to the described embodiments of
the invention without departing from the true spirit and scope of
the invention.
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