# Patent

## Title
E911 call blocking for non-initialized wireless telephones

## Abstract

Calls from a phone identified as being a source of harassing or other undesirable phone calls are blocked at a mobile positioning center (MPC). Upon request by the PSAP, a call record detail can be obtained from the MPC revealing a simulated “callback phone number” as well as a unique number identifier of the phone, such as an ESN or MEID. The MPC then intercepts all future incoming calls from phones with that unique identifier number and routes them to a recording that advises the harasser that the phone has been identified as a harasser and is now blocked. The recording can also advise the caller how to restore service. In a preferred embodiment, the MPC sets a timer to automatically restore service after a designated length of time.

## Background
This application is a continuation-in-part (CIP) of U.S. patent application Ser. No. 11/440,084, filed May 25, 2006, entitled “E911 Call Blocking For Non-Initialized Wireless Telephones” by Richard Dickinson, which in turn claims priority from U.S. Provisional Appl. No. 60/684,554, filed May 26, 2005, entitled “E911 Call Blocking For Non-Initialized Wireless Telephones”, by Richard Dickinson, the entirety of both of which are expressly incorporated herein by reference.


BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to wireless services. More particularly, it relates to E911 wireless services.
2. Background of the Related Art
The FCC has mandated that all wireless telephones must be able to dial 9-1-1, even if other service is denied. This includes uninitialized phones (i.e., cellular phones that have not yet been activated by the wireless carrier). Uninitialized phones have no assigned phone number and are virtually untraceable. Because of this, they have become a popular way for mischief-makers to place hundreds or thousands of harassment calls to Public Safety Answering Points (PSAPs), thereby compromising the ability of the PSAPs to respond to real emergencies.
FIG. 3 shows conventional elements relating to routing of an E911 call from a cell phone.
In particular, as shown in FIG. 3, a conventional wireless carrier's mobile switching center (MSC) 502 contacts a Mobile Positioning Center (MPC) 504 to ascertain proper routing of an E911 call. The MPC 504 responds with routing information and the MSC 502 then routes the call to the correct PSAP 208. The MPC 504 stores the caller's call-back number and location in a dynamic database and relays that information to the PSAP 208 at the appropriate time.
Currently, uninitialized phones are identified only with a nonfunctional, simulated “callback” number that consists of a portion of the phone's electronic serial number (ESN). The FCC has authorized wireless carriers to terminate service to these phones if the PSAP identifies the phone as a harasser. Some MSCs are capable of blocking single ESNs, while others are less flexible and must block all uninitialized phones. The effort to block these calls at the MSC 502 is time consuming and troublesome.
Thus, disadvantages of the current solutions include: (1) It requires time consuming manual intervention to block identified calls; (2) Once a call is blocked, it remains blocked until a technician manually restores service; and (3) Some wireless switches cannot block individual telephones.
Moreover, once blocked, the subsequent legitimate user of the phone is not advised that the phone has been blocked.
There is a need for improved technology for blocking E911 calls from a non-initialized wireless telephone deemed to have previously been used to make a harassing or illegitimate call to 9-1-1.
SUMMARY OF THE INVENTION
In accordance with the principles of the present invention, a method of blocking an undesirable call from being routed to an intended recipient comprises associating a simulated callback phone number with the undesirable call. A mobile positioning center (MPC) is queried for routing instructions for the undesirable call. The simulated callback phone number is further refined by ascertaining the unique MEID or ESN of the phone, which is compared with a known list of unique numbers to be blocked. If a match is made by the comparing, routing of the undesirable call to the intended recipient is blocked at the mobile positioning center (MPC).
In accordance with another aspect of the invention, apparatus for identifying an otherwise unidentifiable source phone of an E911 call comprises a simulated callback phone number module. The module associates as a callback phone number a 10-digit simulated callback number comprising “911” plus 7 digits of an electronic serial number (ESN) of the source phone. Even though the ESN or MEID is truncated for the purpose of creating the simulated phone number, the complete ESN or MEID remains intact within the call data flow and it can be accessed after the call in completed via call detail reports.
Apparatus for blocking an undesirable wireless call from being routed according to yet another aspect of the invention comprises a blocked unique number list maintained by a mobile positioning center (MPC). A module compares a unique number (MEID or ESN) associated with a received query for routing instructions to entries in the blocked number list. If a match is made between the unique number of the phone and an entry in the blocked number list, routing to an intended destination is refused.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows exemplary network elements relevant to call blocking for E911 harassment calls, in accordance with the principles of the present invention.
FIG. 2 shows exemplary messaging to accomplish call blocking for E911 harassment calls, in the exemplary system shown in FIG. 1.
FIG. 3 shows conventional elements relating to routing of an E911 call from a cell phone.



DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
In accordance with the principles of the present invention, calls from a phone identified as being a source of harassing or other undesirable phone calls are blocked at a mobile positioning center (MPC), rather than at the MSC as in conventional systems. Upon request by the PSAP (e.g., a PSAP designated as servicing the location from which the harassing call originates or is registered in), a call record detail can be obtained from the MPC revealing a simulated “callback phone number” of the mobile phone identified to have made a harassing call to the specific PSAP at a specific time. Because simulated “call back numbers” can in extremely rare occasions be duplicated, resulting in the remote possibility of blocking legitimate calls from a phone with a similar number, the call detail record is further referenced to obtain a unique identifier number related to that particular phone. Typically, that unique identifier number would be the MEID or the phone's Electronic Serial Number (ESN) The MPC then intercepts all future incoming calls from that phone corresponding to the unique identifier number, and routes this and any future calls therefrom to a recording that advises the harasser that the phone has been identified as a source of harassing phone calls and is now blocked. The recording can also advise the caller how to restore service. In a preferred embodiment, the MPC sets a timer to automatically restore service after a designated length of time.
FIG. 1 shows exemplary network elements relevant to call blocking for E911 harassment calls, in accordance with the principles of the present invention. The disclosed wireless infrastructure is implemented to support subsequent 9-1-1 calls.
In particular, as shown in FIG. 1, a mobile phone 173 communicates with a given cell site 174. The cell site 174 communicates with a mobile switching center (MSC) 202 in a wireless carrier's network. The mobile switching center (MSC) 202 is the wireless equivalent to a landline end office.
Importantly, according to the invention, the MSC 202 includes a simulated callback phone number module 202a. The simulated callback phone number module 202a provides a simulated callback number for a given wireless phone calling 911. In the disclosed embodiments, the simulated callback number comprises “911” plus the last 7 digits of the ESN (totaling 10 digits) of the phone sending the undesirable call. This format is typical per current industry standards for simulated callback number, but it is envisioned that this format can be modified in any manner that uniquely identifies the telephone, and/or is mutually agreeable to the MPC and the MSC and the PSAP.
An appropriate mobile positioning center 204 also communicates with the ALI database 210 and the coordinate routing database (CRDB) 212. The mobile positioning center (MPC) 204 is the call routing “mastermind” that maintains a database of cellular towers and which PSAPs should receive calls from which cellular tower. The MSC 202 relies upon the MPC 204 to determine which selective router should receive the E911 call. The MPC 204 also communicates with the PSAP 208 to inform the PSAP 208 of the caller's phone number and address.
The MSC 202 queries the MPC 204 for call routing instructions, and provides to the MPC 204 the simulated callback number across dedicated data circuits 102. Preferably, the query from the MSC 202 includes not only the simulated callback number (911+last 7 digits of the ESN), but also the cellular tower from where the call originated. The MPC queries the Harasser Number Data Base 216 to see if the simulated callback number is listed. In the absence of a match in the Harasser Number Database 216, the MPC 204 queries a coordinate routing database (CRDB) 212, which determines that calls originating from which cell towers should be routed to which PSAPs. The MPC 204 responds with appropriate call routing instructions. These instructions consist of a pseudo automatic number identifier (pANI) that relates to a specific trunk group 103 (e.g., CAMA or SS7 voice trunk) between the MSC 202 and the selective router 206. The MSC 202 directs the call to the selective router 206 via the identified trunk group 103. The E911 call is routed to the appropriate public safety answering point (PSAP) via the selective router 206, which has been provisioned to relate the specified pANI to a specific trunk group 104 that connects the selective router 206 to the intended PSAP 208. Upon receipt of the emergency call with the specified pANI, the selective router 206 routes the call to the PSAP 208. The selective router is provisioned as is otherwise conventional.
The E911 call continues on to an ANI/ALI controller 275 or similar device within the PSAP 208, which communicates with an automatic location identifier (ALI) database 210, and ultimately on to a PSAP workstation manned by appropriate emergency personnel. The ALI database 210 is provisioned with the pANI so that queries using that pANI are routed to the MPC that initially issued the pANI. The ANI/ALI controller 275 queries the ALI 210 for ALI data related to the pANI. The ALI 210 routes the query to the MPC 204 via existing data circuits 105. The MPC 204 responds with the simulated callback number of the uninitialized phone.
TCP/IP data circuits 105 must be ordered and installed between the MPC 204 and the various ALI databases 210.
Web based Graphical User Interface 107 with appropriate access restrictions must be installed at the Harassment Number Database 216. This interface is used for the PSAPs to identify harassing telephones according to their simulated callback number. Alternatively, this communications can be verbal, via fax, or other device between authorized personnel at the PSAP and personnel managing the Harasser Number Database 216.
FIG. 2 shows exemplary messaging to accomplish call blocking for E911 harassment calls, in the exemplary system shown in FIG. 1.
In particular, as shown in FIG. 2, an initial harassing call is placed from the mobile phone 173 through a given cell site 174. The call flow shown in FIG. 2 traces a wireless harassment call from the uninitialized mobile phone 173, then designates it as a harassing call.
As shown in step 101 of FIG. 2, the receiving cell site routes the 911 call to the MSC 202. The MSC 202 receives the call.
In response to receipt of the E911 wireless call, the simulated callback phone number module 202a is activated, and in response appends a 10-digit simulated callback phone number to the E911 call (“911” plus the last 7 digits of the ESN of the uninitialized phone.)
The MSC 202 then queries the MPC 204 for routing information for the E911 call, which at that point includes the 10-digit simulated callback phone number. Preferably, the query from the MSC 202 includes not only the simulated callback number (911+last 7 digits of the ESN), but also the cellular tower from where the call originated.
As shown in step 102, upon determining the appropriate PSAP to receive the call, the MPC 204 responds with an appropriate pANI. This pANI is, e.g., a 10-digit number compatible with the existing selective router 206 that serves that PSAP 208. The ESRK is preferably unique to that PSAP 208.
In step 103, the MSC 202 routes the 911 call to the designated selective router 206.
In step 104, upon reaching the selective router 206, the existing E911 infrastructure delivers the call to the PSAP 208. The selective router 206, previously provisioned to recognize the pANI in the ANI field of the CAMA or SS7 voice call, routes the call to the appropriate PSAP.
In step 105, per current existing technology, the PSAP 208 receives the voice call and using the pANI, queries the ALI database 210 for the location and call-back information. The ALI database 210 steers the pANI to the appropriate MPC 204, which responds to the ALI query with the simulated “callback” number of the originating phone.
In step 106, the harasser harasses. For example, the harasser might merely breath heavily into the phone, whisper juvenile obscenities, whatever, and typically refuse to hang up.
In step 107, the PSAP dispatcher terminates the call, and in accordance with the principles of the present invention, notifies the MPC 204 of the simulated “callback” number associated with a harassing or prank 911 phone call.
In step 108, personnel at the MPC 204 access the call detail report related to the call and ascertain the ESN or MEID or other unique identifier of the phone. This unique identifier is listed in a suitable database of calls to be blocked from PSAPs in the future. The database may be a separate, special database, or may be integrated within a larger database. This database is represented by the harasser number database 216 shown in FIGS. 1 and 2.
In a preferred embodiment, personnel at the MPC 204 also assign a “timeout” period after which the simulated callback number that was listed in the harassing database is purged from the harassing database. At this point, the phone 173 would be free to call again, even as a harasser. However, given that a predefined period of time has elapsed since the last harassing call has been given from that phone 173, it is unlikely that the original harasser would harass again from the phone 173.
The timeout period may alternatively be automatically set without the need for operator intervention. Secure IP interfaces may be made available to PSAP personnel who invoke the timeout period directly.
As an alternative, rather than being purged, the callback number may be maintained in the blocked number database but de-activated or enabled in some way that maintains a record of the previous harassing 911 phone call made using that callback number. This allows normal operation of the wireless phone, but also a record of the undesirable harassing call made from that phone 173.
In step 109, the harasser might again dial 911. Again the MSC 202 activates the simulated callback phone number module 202a and appends a 10-digit simulated callback phone number to the 911 call. Again the MSC 202 routes the call to the MPC 204 per otherwise conventional processes.
However, this time, as shown in step 110, the MPC 204 compares the unique identifier of the phone against entries in the harasser number database 216. In the given scenario, this time the MPC 204 recognizes the unique identifier number in the special harassing 911 dialer's database 216. As a result, the MPC 204, this time, responds with routing instructions to a 10-digit PSTN number of a pre-recorded announcement message element 279 instead of routing information to the otherwise designated PSAP 208.
The pre-recorded message played by the recording element 279 can, of course, be programmed to say anything. As an example, the pre-recorded message might state something like: “911 calls from this phone have been blocked because this phone has been identified by law enforcement authorities as a source of telephone harassment. To restore 911 service, please contact XYZ Wireless. Goodbye.”
In step 111, after a given “timeout” period of time later (e.g., several hours, one or more days, etc. later), the relevant entry of the simulated callback number corresponding to the harassing 911 dialer's phone 173 is automatically purged from the harasser number database 216, and normal 911 service is thus restored. Of course, a record of the phone having been listed in the harasser number database 216 along with pertinent information such as when the harassing call was made, the location of the phone when the harassing call was made, etc., may be recorded for later review by appropriate personnel.
Note that the inventive blocking technology will work to block calls from any wireless phone presumably desired not to be routed to a PSAP. The example of an uninitialized phone is used because uninitialized phones are the most commonly used type phones for harassment, and also are the most difficult to trace.
The present invention provides technology that results in the reduction of the waste of 911 emergency service resources caused by prank or harassing 911 calls made from uninitialized wireless devices. In extreme emergencies where time saves lives, the present invention might also be credited with the capability of saving lives that might otherwise be lost due to the delay or even failure of a legitimate 911 caller from a wireless device to reach 911 responders caused while the relevant PSAP 208 is tied up dealing with a prankster or harasser.
The principles of the present invention can also be implemented to route specific legitimate callers to specific 911 resources. For example, a person with a heart condition may purchase a special wireless phone solely for the purpose of dialing 911 in the event of a heart attack. At the prior request of the caller, their phone number may be maintained in a special database similar to the harassing 911 caller's database 216. Then, in accordance with the principles of the present invention, any/all 911 calls made from that particular phone with a phone number previously entered into the special database can be routed directly to a medical responder or other designated phone (e.g., their surgeon, etc.)
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.

## Claims

1. A method of blocking an undesirable emergency voice call from being routed to an intended phone device, comprising:
associating a simulated callback phone number with a unique phone device identifier number and an undesirable emergency voice call;
querying a mobile positioning center (MPC) for routing instructions for said undesirable emergency voice call, said mobile positioning center (MPC) being distinct and remote from a mobile switching center (MSC);
comparing said simulated callback phone number and said unique phone device identifier number with a known list of phone devices to be blocked; and
if a match is made by said comparing, blocking routing at said mobile positioning center (MPC) of said undesirable emergency voice call to said intended phone device, by said MPC sending routing instructions including a routing number of a pre-recorded announcement element.

2. The method of blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 1, wherein:
said undesirable emergency call is a 911 call.

3. The method of blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 1, wherein:
said designated recipient is a public safety answering point (PSAP).

4. The method of blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 1, wherein:
said simulated callback phone number is a 10-digit number.

5. The method of blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 4, wherein said 10-digit simulated callback phone number comprises:
“911” plus 7 digits corresponding to the electronic serial number (ESN) of the phone sending said undesirable emergency call.

6. The method of blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 5, wherein:
said 7 digits are the last 7 digits of said ESN.

7. Apparatus for blocking an undesirable emergency voice call from being routed to an intended phone device, comprising:
means for associating a simulated callback phone number with a unique phone device identifier number and an undesirable emergency voice call;
means for querying a mobile positioning center (MPC) for routing instructions for said undesirable emergency voice call, said mobile positioning center (MPC) being distinct and remote from a mobile switching center (MSC);
means for comparing said simulated callback phone number and said unique phone device identifier number with a known list of phone devices to be blocked; and
means for blocking routing at said mobile positioning center (MPC) of said undesirable emergency voice call to said intended phone device if a match is made by said means for comparing, by said MPC sending routing instructions including a routing number of a pre-recorded announcement element.

8. The apparatus for blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 7, wherein:
said undesirable emergency call is a 911 call.

9. The apparatus for blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 7, wherein:
said intended phone is a public safety answering point (PSAP).

10. The apparatus for blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 7, wherein:
said simulated callback phone number is a 10-digit number.

11. The apparatus for blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 10, wherein said 10-digit simulated callback phone number comprises:
“911” plus 7 digits corresponding to an electronic serial number (ESN) of a sending phone device of said undesirable emergency call.

12. The apparatus for blocking an undesirable emergency voice call from being routed to an intended phone device according to claim 11, wherein:
said 7 digits are the last 7 digits of said ESN.

13. Apparatus for blocking an undesirable wireless emergency voice call from being routed, comprising:
a blocked phone list maintained in electronic storage by a mobile positioning center (MPC) that is distinct and remote from a mobile switching center (MSC), said blocked phone list comprising a unique phone device identifier;
a module to compare a callback number associated with a received, at said mobile positioning center (MPC), query for routing instructions to unique identifier phone device numbers in said blocked phone list; and
if a match is made between said callback number and said unique identifier phone device number in said blocked phone list, blocking routing at said mobile positioning center (MPC) of an undesirable wireless emergency call to an intended destination phone device, by said MPC sending routing instructions including a routing number of a pre-recorded announcement element.

14. The apparatus for blocking an undesirable wireless emergency voice call from being routed according to claim 13, further comprising:
if said match is made, providing routing to a predesignated recorded message instructing a calling device of a reason for blocking routing of said undesirable wireless emergency voice call.

15. The apparatus for blocking an undesirable wireless emergency voice call from being routed according to claim 13, further comprising:
a timer to automatically purge entries from said blocked phone number list after a predetermined amount of time.

16. Apparatus for blocking an undesirable wireless emergency voice call from being routed, comprising:
a blocked phone list maintained in electronic storage by a mobile positioning center (MPC) that is distinct and remote from a mobile switching center (MSC), said blocked phone list comprising a unique phone device identifier;
means for comparing a callback number associated with a received, at said mobile positioning center (MPC), query for routing instructions to unique phone device identifier numbers in said blocked phone list; and
means for blocking routing, at said mobile positioning center (MPC), of said undesirable wireless emergency voice call to an intended destination phone device if a match is made between said callback number and said unique phone device identifier number in said blocked phone list, by said MPC sending routing instructions including a routing number of a pre-recorded announcement element.

17. The apparatus for blocking an undesirable wireless emergency voice call from being routed according to claim 16, further comprising:
means for providing routing, to a predesignated recorded message instructing a calling device of a reason for blocking routing of, said undesirable wireless emergency voice call if said match is made.

18. The apparatus for blocking an undesirable wireless emergency voice call from being routed according to claim 16, further comprising:
means for automatically purging entries from said blocked phone list after a predetermined amount of time.