Patent Document

RELATED APPLICATIONS 
       [0001]    This application is a divisional application of co-pending U.S. patent application Ser. No. 11/526,094 which in turn claims the benefit of priority from U.S. Provisional Patent Application No. 60/719,742, filed on Sep. 22, 2005, and U.S. Provisional Patent Application No. 60/757,113 filed on Jan. 5, 2006, the entirety of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to the field of emergency services communications. More particularly, the present invention relates to the field of emergency services communications in connection with VoIP (Voice Over Internet Protocol). 
       BACKGROUND 
       [0003]    Currently, the rise in use of VoIP (Voice Over Internet Protocol) telephones has outpaced the ability of emergency telephone systems, such as 9-1-1, to handle these types of calls. First, because VoIP telephone calls do not originate from fixed physical locations in the same manner as landline telephone calls, it is difficult to ensure that the emergency call is sent to the appropriate local PSAP (Public Safety Access Point) responding to the location of the 9-1-1 call, such as the local police, local fire or local 9-1-1 emergency call center. 
         [0004]    Secondly, once a call is handled by a PSAP the use of VoIP telephone has further complicated the ability to detect the location of a caller when an emergency call is placed. 
         [0005]    For example, when a caller uses a VoIP telephone, the call is generally placed though the internet or other such packet switched network. Thus, when a dial string such as 9-1-1 is placed, the devices/routers handling the call do not have the capacity to properly determine the location of the caller to route the calls to a local PSAP through the internet. Although PSAP&#39;s may be able to handle incoming VoIP internet calls, the outgoing VoIP routers would not know which local PSAP to send them to, since the location of the VoIP caller is unknown. 
         [0006]    Furthermore, in standard landline telephone calls made to 9-1-1 or other similar emergency telephone numbers, the 9-1-1 call center is able to trace the physical location of the caller through a standard call trace since the location of the line is fixed. This is particularly useful when a caller is not able to give their location either because they do not know their location or they are physically unable to verbalize their location. Also, with cellular callers, GPS (Global Positioning System), other location systems, or cell tower triangulation can be used to physically locate an emergency caller. 
         [0007]    However, with VoIP telephones the call is connected to the destination telephone via the internet. This makes it difficult and/or impossible to easily trace the physical location of caller if they are unable to give the location on their own. This presents an added difficulty in directing emergency personal in the case of a 9-1-1 or other emergency call that is placed from a VoIP phone. 
       OBJECTS AND SUMMARY 
       [0008]    The present invention looks to overcome the drawbacks associated with the prior art and to provide a system and method for emergency call centers to obtain the location of a VoIP caller in the case of an emergency call. 
         [0009]    To this end, the present invention provides for a method for determining the location of a VoIP caller including receiving a call from a VoIP phone, where the VoIP phone accesses the internet via a VoIP enabling device. A device identifier of the VoIP enabling device through which the call from the VoIP device originated is received. The device identifier is compared against a pre-defined table of device identifiers, where each device identifier in the table has an associated physical location. The physical location of the VoIP enabling device is returned during the call from the VoIP phone. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The present invention can be best understood through the following description and accompanying drawings, wherein: 
           [0011]      FIG. 1  illustrates an arrangement for a VoIP emergency system, in accordance with one embodiment of the present invention; 
           [0012]      FIG. 2  is a flow chart for a PSAP telephone call placed through the VoIP system of  FIG. 1 , in accordance with one embodiment of the present invention; 
           [0013]      FIG. 3  illustrates an arrangement for a VoIP emergency system, in accordance with another embodiment of the present invention; 
           [0014]      FIG. 4  is a flow chart for a PSAP telephone call placed through the VoIP system of  FIG. 3 , in accordance with one embodiment of the present invention; 
           [0015]      FIG. 5  illustrates an arrangement for a VoIP emergency system, in accordance with another embodiment of the present invention; 
           [0016]      FIG. 6  illustrates a MAC address table, in accordance with one embodiment of the present invention; 
           [0017]      FIG. 7  is a flow chart for a PSAP telephone call placed through the VoIP system of  FIG. 5 , in accordance with one embodiment of the present invention; 
           [0018]      FIG. 8  illustrates an arrangement for a VoIP emergency system, in accordance with another embodiment of the present invention; 
           [0019]      FIG. 9  illustrates an arrangement for a VoIP emergency system, in accordance with another embodiment of the present invention; 
           [0020]      FIG. 10  illustrates an arrangement for VoIP emergency system with multiple access points for the VoIP phone, in accordance with one embodiment of the present invention; 
           [0021]      FIG. 11  is a flow chart for a PSAP telephone call placed through the VoIP system of  FIG. 10 , in accordance with one embodiment of the present invention; and 
           [0022]      FIG. 12  illustrates an arrangement for VoIP emergency system with multiple access points for the VoIP phone, in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In one embodiment of the present invention, a first arrangement is shown illustrating a typical VoIP installation for a commercial office setting. Here, a plurality of VoIP telephones  10   a - 10   x  are preferably connected to a PBX (Private Branch Exchange) device  12  that handles both VoIP calls as well as landline calls, and routes each call as necessary. 
         [0024]    For VoIP calls originating from VoIP phones  10 , PBX  12  typically routes the call through the internet, shown as element  14 . For calls from other phones (not shown) connected to PBX  12 , such as landline phones in the office building, these call are routed outbound over the PSTN (Public Switched Telephone Network), shown as element  16 . As illustrated in  FIG. 1 , a local PSAP (Public Safety Access Point)  18 , such as a 9-1-1 answering service, local police or local fire company is capable of receiving incoming communications from either the PSTN  16  or the internet  14 . 
         [0025]    As illustrated in flow chart  FIG. 2 , at a first step  100 , a caller located at one of VoIP telephones  10  experiences an emergency and dials 9-1-1 or some other emergency access number. At step  102 , the call is forwarded to PBX  12  for routing to the intended destination. 
         [0026]    According to the arrangement of the present invention, at step  104 , PBX  14 , instead of automatically sending call 9-1-1 call by the internet  14  to PSAP  18 , parses the communication to determine if it includes a dial string related to an emergency service. If not, the call is routed over Internet  14 , as per normal call flow. In the present example, because the caller dialed 9-1-1, PBX  12  recognizes an emergency request dial string. 
         [0027]    Thus, at step  106 , instead of routing the call via the internet  14  to PSAP  18 , PBX  12  converts the call to a landline call internally, and routes the call to PSAP  18  using the PSTN  16 . This is done even though PSAP  18  could have received the call by the internet  14 . Even though PSAP  18  would have gotten the call, by converting and re-routing the call through PSTN  16 , PSAP  18  is able to take additional advantage of traditional call tracing to identify the location of the caller (ie. location of PBX  12 ). Thus, by the present invention a call originating from a VoIP phone  10  directed to a PSAP  18  allows them to locate the location of the caller. 
         [0028]    In another embodiment of the present invention, an arrangement for reaching a PSAP using a CDMA/VoIP smart phone is described, where the PSAP can determine the location of the caller. Here CDMA/VoIP smart phone  110  operates as a typical smart phone. When WiFi is available to smart phone  110 , it attempts to complete the call as VoIP to save airtime. Alternatively, if no WiFi is available, smart phone  110  simply handles the call by CDMA technology. 
         [0029]    Thus, a typical connectivity arrangement, as shown in  FIG. 3 , shows smart phone  110  having connections with either one of or both traditional CDMA cell towers  112  and a WiFi enabling device  114 . WiFi enabling device  114  is typically a wireless router however, any wireless capable internet access points, capable of receiving WiFi communications from smart phone  110  and communicating them through the internet, are within the contemplation of the present invention. 
         [0030]    CDMA cell towers  112  connect smart phone  110  to the desired party via traditional cellular transmission methods. WiFi device  114  is coupled to the internet, pictured as  116 , to complete the call by VoIP methodology. A PSAP  118  is coupled to both internet  116  and the CDMA cell tower  112  telephony connection equipment (including the combined mobile networks and PSTN and any other components of tradition cellular telephony connectivity). 
         [0031]    According to the present invention, as illustrated in flow chart  FIG. 4 , at a first step  200 , a caller using CDMA/VoIP smart phone  110  experiences an emergency and dials 9-1-1 or some other emergency access number. At step  202 , smart phone immediately parses the dial string to determine if it is an emergency string or if it is just a standard telephone call. If it is a standard call, then at step  204  the call is simply routed via WiFi device  114  if available, or, if not available, then over cell tower network  112 . 
         [0032]    However, in the present example where the dial string is an emergency call, smart phone  110 , at step  206  regardless of the availability of WiFi device  114 , smart phone  110  routes the call through CDMA routing via cell towers  112 . This is done even though PSAP  118  could have received the call by the internet  116 . Even though PSAP  118  would have gotten the call, by choosing and routing the call through cell towers  112 , PSAP  118  in addition to simply receiving the call, is able to take additional advantage of available caller location technology such a tower triangulation, GPS or other location technologies available from the mobile service provider to identify the location of the caller. Thus, by the present invention, a call originating from CDMA/VoIP smart phone  110  directed to a PSAP  118  allows PSAP  118  to locate the location of the caller. 
         [0033]    Obviously, if the dial string were recognized as an emergency call, and only WiFi device  114  were available, the call would still be completed to PSAP  118 , even if no location were available. If available the physical location of WiFi device  114  may be known if otherwise registered with PSAP  118  as described in more detail below. 
         [0034]    In another embodiment of the present invention, as illustrated in  FIG. 5 , another typical caller may employ a VoIP only phone  310  that is connected to the outside world via a physical Ethernet-to-SIP converter box  312  physically plugged into their DSL or Cable Modem  314  at home. This arrangement of VoIP telephony connectivity make up a substantial portion of the PSTN (Public Switched Telephone Network) enabled VoIP connections. Here, soft phone  310  generates a telephony communication which can either be sent by PSTN  316  or via the internet  320  depending on how converter box  312  is arranged. 
         [0035]    According to the present invention when converter box  312  is operating to convert the calls to PSTN landline calls, then when 9-1-1 or other emergency calls are placed via VoIP only phone  310 , the calls are routed to a local PSAP  318  via PSTN  316 . 
         [0036]    However, when box  312  is set to deliver communications via modem  314  and subsequently internet  320 , then PSAP  318  may determine the location by way of tracing the MAC (Media Access Control) address of the devices used in the communication by consulting a MAC address table  322  stored in Physical location MAC address database  324 . 
         [0037]    The physical SIP/PSTN converter  312  connected to the network (PBX or other home modem our router  314 ) has a unique MAC address that can be used to provide the physical path—from the converter  312 , to the router and then onto the DSL or Cable Modem  314 , to the network and out over internet  320 . Each of these devices has a MAC (Media Access Control) address, a fixed and unique identifier that can be used for PSAPs  318  services to assist in obtaining the location of the caller. Thus, in one embodiment of the present invention, by using the MAC address of the nodes  312  and  314  in the network, the physical location of the VoIP phone path through the various VoIP call routers is sufficient to give a physical location of a VoIP phone  310  to PSAP  318 . 
         [0038]    For example, according to the present invention PSAP  318  can determine the location of an emergency caller using a VoIP telephone  310  by utilizing the MAC (Media Access Control) address of the physical. SIP/PSTN converter  312 . Because the physical location of the device  312  making the converted landline call is known to PSAP  318  as discussed below, a local call trace to the device can be used, not available on traditional VoIP telephone calls. 
         [0039]    In order to facilitate this, a MAC address table  322  is stored in physical location MAC address database  324 . As illustrated in  FIG. 6 , MAC address table maintains a first MAC number field  326  and a second physical location field  328  with an entry associated with each the MAC number field  326  entry in table  322 . 
         [0040]    MAC address table  322  can be generated either by a simple software set-up operation, where devices  312 ,  314  etc. . . . involved with VoIP communications can register with service that maintains table  322 . This process can be voluntary at set-up, voluntary at a later time frame (ie. by request) or even carried out by a local PSAP  318 . For example, a process of e-mail invitations may be used by PSAP  318  or the third party organizer of table  322  to request registration of WiFi device  314 . It is understood that the present invention contemplates that the service for setting up MAC address table  322  and location database  324  on which it resides is handled either by PSAP  318  itself, by PSAP  318  with third party software support or entirely off-site by a third party operator. 
         [0041]    As illustrated in  FIG. 5 , MAC address table and MAC location database  324  are pictured outside of PSAP  318 . However, this is in no way intended to limit the scope of the present invention. MAC location database  324  and table  322  may be maintained either within the physical location of PSAP  318  or instead by a third party operator physically located remotely from PSAP  318 . 
         [0042]    It is also noted that PSTN  316  replacement VoIP providers can detect when the MAC address path changes. When the SIP Phone  310  or converter VOX  312  registers itself onto the network, at that point, a call to the user of VoIP phone  310  and converter  312  can be placed requesting an updated address. Such a registration process takes seconds, and would solve any location quandaries for PSAP  318 . 
         [0043]    In one embodiment of the present invention as illustrated in flow chart  FIG. 7 , an exemplary call flow from VoIP phone  310  to PSAP  318  over internet  320  is shown. At a first step  300 , a caller dial 9-1-1 or another emergency number using VoIP phone  310 . At step  302 , converter  312  and modem  314  send the call out over internet  320 . Next, at step  304 , the call is routed to PSAP  318  which receives the call via their incoming VoIP call equipment. 
         [0044]    According to the present invention, at step  306 , while handling the call from VoIP phone  310 , PSAP  318  pings MAC address table  322  at MAC database  324  to see if the MAC address of the incoming call is listed. If not, then the call with PSAP  318  proceeds as normal, but it is conducted without the benefit of any auto-location of the caller. However, if the MAC address of the network equipment  312  or  314  of the incoming call is found in table  322 , then the physical location of the equipment, such as box  312  or modem  314 , is sent to the operator at PSAP  318 . At step  308 , as confirmation, the operator at PSAP  318  may ask to confirm the location if the caller is lucid and aware of their location. It is noted that in the case where a VoIP emergency call comes in and no associated MAC address is found in table  322  then a record is made of the incoming MAC address and an invitation is sent to the owner or manager requesting that the register device  314  in table  322  for future calls. 
         [0045]    In another embodiment of the present invention, as illustrated in  FIG. 8 , another arrangement shows PSAP  418  connectivity for users who run all of their phone conversations through softphones  410  or other VoIP devices  411  or via their laptops  412 . Here, unlike either the softphones via PBX or smart phone with CDMA, the calls from these VoIP phones  410  are handled exclusively through the internet. Similar to the previous arrangement from  FIG. 5 , laptops  412  are presumably in wireless contact with WiFi enabling device  414 , which are connected to the internet  416 , and which in turn are connected to PSAP  418 . 
         [0046]    According to this embodiment of the present invention, a MAC address table  422  is generated and stored in Physical location MAC address database  424 . Similar to the MAC address table  322  from  FIG. 6 , MAC address table  422  maintains a first MAC number field  426  and a second physical location field  428  associated with the MAC number field  426  for each MAC address entry in table  422 . Likewise, the call flow from  FIG. 7  is repeated in the case of emergency calls from VoIP phone  410  or laptop  412 . 
         [0047]    Regardless of the registration process for the physical locations of the WiFi routing devices  314  or  414  it is known that WiFi networks have very limited radii—typically only as large as a house, office, coffee shop, or airport lounge. When the VoIP Phone  310  or  410  registers itself on the network, the WiFi based station&#39;s MAC address can be identified and the physical location of the caller be identified. Since WiFi networks don&#39;t really “roam”, there is not need to track locations using a triangulation system. The registration process also enables WiFi routers  314  and  414  to identify the correct local PSAP  318  or  418  to ensure that any VoIP telephone call that is sent therethrough is routed to a PSAP  318  or  418  that is both local and capable of handling incoming VoIP calls. 
         [0048]    In another embodiment of the present invention, as illustrated in  FIG. 9 , road users of a softphone  510  may benefit from the present invention. Here VoIP phones  510  move along a road from one cell tower  512  to the next and through WiFi hotspot  514  to the next. Each of cell towers (and associated telephony connectivity equipment)  512  and WiFi devices  514  are connected to local PSAPs  318 . 
         [0049]    In the case of the road user using a CDMA (GSM 3G)/VoIP phone then the call arrangement would operate similarly to  FIGS. 3 and 4  described above. 
         [0050]    In the case of cellular towers  512  not being available or if phone  510  is VoIP only then the operation would occur similarly to  FIG. 5 through 7  above. 
         [0051]    In another embodiment of the present invention, it is contemplated that the location of VoIP phone  510  may be determined based on relative signal strength when more than one tower  512  or WiFi device  514  is within range of phone  510 . Although this may be more common in the case of a traveling VoIP phone  510  as shown in  FIG. 9 , it is contemplated that such an arrangement is equally applicable in any of the above described arrangements. 
         [0052]    For example, as illustrated in  FIG. 10 , a range estimation and location system  600 , may be used to determine the location of VoIP phone  610  by employing the VoIP device&#39;s  610  internal signal strength list. 
         [0053]    In general VoIP communication devices  610  perform a scan of nearby access points and their corresponding MACs before establishing a connection to a desired access point and initiating a call. However, a user may choose an access point that is farther away than the closest access point for reasons besides simple signal strength. For example, a more remote, but adequate access point may be free. However, when responding to an emergency call, ideally the PSAP should respond in the direction of the closest access point to the caller, regardless of whether or not they are using this access point, assuming both access points are registered. 
         [0054]    In the present invention, a range estimation and location system  600  is employed by PSAP  618 . As with the previous embodiments such a system  600  may be employed externally or even by a third party operator. 
         [0055]    Thus, in situation where VoIP phone  610  is located between a first closer WiFi device  614   a  and a second farther WiFi device  614   b , VoIP phone  610  maintains the signal strengths of both, but chooses a connection to the later, WiFi device  614   b . It is understood that both WiFi devices have significantly limited geographic coverage relative to the geographic area covered by PSAP  618  and thus, both WiFi devices  614   a  and  614   b  are registered to the same PSAP. 
         [0056]    In one embodiment of the present invention, as illustrated in flow chart  FIG. 11 , at step  700 , a caller dials 9-1-1 or some other VoIP phone  610 . At step  702  the call is sent to the local PSAP  618 , via connectivity through WiFi device  614   b . Simultaneously, the signal strengths of all available WiFi devices  614  are sent to, or otherwise electronically requested/retrieved by, PSAP  618 . 
         [0057]    At step  704 , PSAP  618  consults a MAC address table  622  in MAC database  624 , similar to the ones shown above in  FIG. 6 . At step  706 , the MAC address of the incoming call is compared against MAC field  626  and location of WiFi device  314   b  is determined from field  628 . 
         [0058]    According to the present embodiment, at step  708 , in addition to checking the location of WiFi device  314   b , system  600  further imports or retrieves all of the WiFi data (signal strengths) on available WiFi devices  614  for VoIP phone  610 , such as WiFi device  614   a  and also consults MAC address table  622  for their locations as well. 
         [0059]    At step  710 , system  600  compares the signal strength of WiFi device  614   b , upon which the VoIP call was placed, to the signal strength of WiFi device  614   a , which is closer to VoIP phone  610 , but not being used for the call. At step  712 , PSAP selects WiFi device  614   a  for determining the location of VoIP phone  610 , because it assumes that VoIP phone  610  is in closer proximity to WiFi device  614   a  than WiFi device  614   b , even though the call connection is through device  614   b , because the signal strength from VoIP phone  610  to device  614   a  is higher. 
         [0060]    Obviously, the present system could be expanded to accommodate as many WiFi devices that are in the range of VoIP phone  610  and registered to MAC address table  622 . Also, if for any reason the higher signal strength WiFi device  614   a  is not registered to MAC address table  622 , system  600  of PSAP  618  may still use the lower signal strength WiFi device  614   b , through which the call was placed to trace the call as per the examples above in  FIGS. 7 and 8 . 
         [0061]    In accordance with another embodiment of the present invention, using the imported signal strengths to VoIP phone  610  from WiFi device  614  as discussed above may be further used to estimate distance from the closest location similar to a triangulation operation. 
         [0062]    For example, as illustrated in  FIG. 12 , an 9-1-1 emergency call from VoIP phone  610  to PSAP  618  from WiFi device  614   x  is shown, where WiFi devices  614   x ,  614   y  and  614   z  are all possible available networks. System  600  when importing the WiFi signal strengths notes that device  614   x  has a strength of 100%,  614   y  has a strength of 20% and  614   z  has a strength 60%. Thus, in addition to system  600  choosing WiFi device  614   x  to base the location determination on, system  600  will further know that VoIP phone  610  is closer device  614   z  than device  614   y  and may further employ this information to assist in locating the caller. 
         [0063]    It is understood that while the above described exemplary embodiments of the invention are described in terms of emergency situations, the present invention using a MAC address table for locating callers by WiFi access point locations may also be used in non-emergency situations as well. 
         [0064]    For example, a link on a user&#39;s softphone or other VoIP unit, such as “Locate Me” link may be provided. By activating the link a provider employing the system of the present invention may locate the caller using the MAC or IP address of the access point network device as discussed above. 
         [0065]    Such an arrangement allows a faster real-time knowledge of the location of the VoIP caller so that the MAC address look up does not need to be carried out after a 9-1-1 call. Also, if authorized, it may allow the system to let the real time location of the VoIP operator to be provided to other members of friends list. 
         [0066]    While only certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes or equivalents will now occur to those skilled in the art. It is therefore, to be understood that this application is intended to cover all such modifications and changes that fall within the true spirit of the invention.

Technology Category: 5