Abstract:
An apparatus and method locate a portable telecommunication terminal for emergency telephone call to a public safety answering point by detecting the emergency telephone call, communicating the emergency telephone call to the public safety answering point, and enabling a transmission device in the portable telecommunication terminal so that the portable telecommunication terminal maybe located by personnel that are dispatched by the public safety answering point using a transceiver to locate the transmission device.

Description:
TECHNICAL FIELD  
       [0001]     This invention relates to locating a telecommunication terminal that has placed an emergency call.  
       BACKGROUND OF THE INVENTION  
       [0002]     Within the prior art, a problem exists in attempting to identify a portable telecommunication terminal that has placed an emergency telephone call. It is necessary to locate the portable telecommunication terminal so that assistance can be rendered to the user of the portable telecommunication terminal. Portable telecommunication terminals may be a cellular telephone, an in-building wireless telephone, an IP telephone, etc.  
         [0003]     In the absence of obstructions, it is known within the prior art to utilize global positioning satellite (GPS) devices to determine the position of the portable telecommunication device and to convey this information to the emergency center. In addition, it is known within cellular telephone systems to utilize triangulation to locate portable telecommunication units.  
         [0004]     Whereas the prior art techniques work reasonably well where there are no obstructions, GPS devices do not function well within buildings that utilize reinforced steel floors or roofs. In addition, the utilization of GPS devices adds a considerable amount of money to the cost of a portable telecommunication device.  
         [0005]     Also, the technique of locating a portable telecommunication unit using triangulation suffers from the problem of reflective signals if there are buildings or other objects which can reflect the radio waves. In addition, in a multi-story building where the wireless base stations are located on floors, it is possible for a base station many floors removed to actually be picking up a signal from a wireless handset.  
       SUMMARY OF THE INVENTION  
       [0006]     An apparatus and method locating a portable telecommunication terminal for an emergency telephone call to a public safety answering point by detecting the emergency telephone call, communicating the emergency telephone call to the public safety answering point, and enabling a transmission device in the portable telecommunication terminal so that the portable telecommunication terminal maybe located by personnel that are dispatched by the public safety answering point using a transceiver to locate the transmission device. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0007]      FIG. 1  illustrates an embodiment of a wireless telecommunication system;  
         [0008]      FIG. 2  illustrates an embodiment of a wireless telephone;  
         [0009]      FIG. 3  illustrates, in flowchart form, operations performed by an embodiment;  
         [0010]      FIG. 4  illustrates, in block diagram form, an embodiment of a telecommunication switching system with an IP softphone for implementing the invention;  
         [0011]      FIG. 5  illustrates, in flowchart form, operations performed by an embodiment; and  
         [0012]      FIG. 6  illustrates, in block diagram form, an embodiment of a telecommunication switching system with a telecommunication terminal for implementing the invention. 
     
    
     DETAILED DESCRIPTION  
       [0013]      FIG. 1  illustrates a wireless telecommunication switching system. System wireless controller  111  controls the base stations  101 - 107 . Wireless handsets  108  and  109  are also illustrated in  FIG. 1 . One skilled in the art would realize that there would be more base stations and wireless hand sets.  
         [0014]     To understand the operations of the embodiment illustrated in  FIG. 1 , assume that the user of wireless handset  108  has dialed the emergency number. Wireless handset  108  recognizes the fact that the emergency number has been dialed. In one embodiment, wireless handset  108  will immediately activate the emergency transmission device within the wireless handset. In another embodiment, the actuation and frequency utilized by the emergency transmission device is controlled by control signals from emergency center  113 . System wireless controller  111  is responsive to the placement of the emergency call by wireless handset  108  to interconnect wireless handset  108  to emergency center  113 . Note, that wireless handset  108  as illustrated in  FIG. 1  may utilize one of base stations  101 - 103 . The transmission device may be active or passive. An active device would have its own power supply; whereas a passive device would receive its power from RF transmissions of an emergency receiver such as emergency receiver  112 . Such a passive device is disclosed in U.S. Pat. No. 6,265,963, U.S. Pat. No. 6,600,443, and U.S. Pat. No. 6,486,780.  
         [0015]     Assuming, for the sake of example, that wireless handset  108  is within a building or among buildings where there is a large reflection of radio frequencies used by the wireless handsets. In which case, the radio signals utilized by wireless handset  108  to place the emergency call may not be utilized to pinpoint the location of wireless handset  108 . However, the general location of wireless handset  108  is known by the fact that it is utilizing one of the base stations  101 - 103 . The emergency center  113  dispatches an emergency crew which posesses emergency receiver  112 . Emergency receiver  112  utilizes the signal being transmitted from the emergency transmission device of wireless handset  108  to locate wireless handset  108 . In one embodiment, the frequencies generated by the emergency transmission device are lower in frequency than that utilized for the voice transmission by wireless handset  108 . These lower radio frequencies are less susceptible to reflection. Hence, emergency receiver  112  can utilize directional capabilities to locate wireless handset  108 .  
         [0016]      FIG. 2  illustrates, in block diagram form, an embodiment of a wireless handset. Components in this unit include control unit  201  and clock  209  for providing synchronization to: (1) control unit  201  (2) time domain duplexer (TDD)  203  and (3) combine digital-to-analog and analog-to-digital (D/A+A/D) converter  204 . Also included in the illustrated wireless handset are RF transceiver  206 , antenna  207 , and frequency synthesizer  208 . Telephone circuits and keypad section  205  permits dialing telephone digits and actuating control keys for placing and receiving telephone calls. Display  216  and audio transducer  217  are utilized by control unit  201  to provide feedback to the user and to alert the user of various situations.  
         [0017]     Transceiver  206  comprises both a RF transmitter and a RF receiver. Transceiver  206  demodulates voice signals transmitted by a base station and couples these signals via the D/A section of converter  204  and hybrid  210  to loud speaker  212 . Transceiver  206  receives its input analog speech signals from microphone  211 . These analog speech signals are coupled to the transceiver via hybrid  210  and the A/D section of converter  204 . Converter  204  converts the analog signals to digital signals which are then transmitted to RF transceiver  206 . Conventional amplifiers  213  and  214  are employed for amplifying the analog speech signals obtained from microphone  211  and provided to loud speaker  212 . Control messages are transferred via time domain duplexer  203  to control unit  201 . In accordance with various embodiments, control unit  201  actuates and controls transmitter  219  which transmits the emergency signal via antenna  218 .  
         [0018]      FIG. 3  illustrates, in flowchart form, operations performed by one embodiment. The operations illustrated in  FIG. 3  can be performed by a wireless handset such as illustrated in  FIG. 2  or by an IP telecommunication device such as illustrated in  FIG. 4 . Once started from block  300 , decision block  301  determines if the telecommunication terminal is making a call origination. If the answer is no, block  303  performs normal processing before returning control to decision block  301 . If the answer is yes in decision block  301 , decision block  302  determines if the communication terminal is placing an emergency call. If the answer is no, block  307  performs normal processing before returning control back to decision block  301 . If the answer in decision block  302  is yes, block  304  activates the emergency transfer, and block  306  sets up a call to the emergency center such as emergency center  113  of  FIG. 1  before returning control back to decision block  301 .  
         [0019]      FIG. 4  illustrates another embodiment of the invention.  FIG. 4  illustrates IP softphone  400  and IP telephone  412 . Each of these telecommunication terminals has an emergency transmission device for use in accordance with the invention. Both telecommunication terminals utilize voice transmission utilizing the Internet protocol (IP). The characteristic of IP telecommunication terminals is that they can be plugged into any portion of WAN  409  at any time, and enterprise communication switching system  411  has no information concerning the physical location of these devices in a particular room. Enterprise communication switching system  411  does know the general part of WAN  409  in which the IP telecommunication terminal is connected.  
         [0020]     IP softphone  400  is responsive to audio information received from audio receiver  401  to convert this information to digital information via sound card  403 . CPU and memory  408  then transmits the audio information to enterprise communication switching system  411  via IP interface  406 . When audio information is received from enterprise communication switching system  411 , via WAN  409  and IP interface  406 , CPU and memory  408  utilize sound card  403  to convert this information to audio information which can be presented to the user via audio transmitter  402 . CPU and memory  408  perform all of the control functions of IP softphone  400 . When CPU and memory  408  determine that the user is placing an emergency call, CPU and memory  408  perform the operations illustrated in the embodiments of  FIGS. 3 and 5 .  
         [0021]     IP telephone  412  is similar in construction to IP softphone  400  with the exception that IP softphone  400  utilizes computer  404  to provide the conductivity to WAN  409 . IP telephone  412  would simply consist of a processor, IP interface, audio conversion circuits, and an emergency transmission device, with of course the necessary microphone and speaker such as audio receiver  401  and audio transmitter  402 .  
         [0022]     One skilled in the art would readily realize that enterprise communication switching system  411  could be replaced by a telecommunication gatekeeper which would provide the necessary control functions for IP softphone  400  and IP telephone  412 .  
         [0023]      FIG. 5  illustrates, in flowchart form, operations performed by an embodiment. In the embodiment illustrated in  FIG. 5 , the emergency center is given the capability of adjusting the frequency and power of the emergency transmission device. However, if the emergency center does not send such adjustment information within a predetermined time period, the emergency transmission device is automatically turned on at a preset power and frequency. The capability of being able to adjust the frequency and power of the emergency transmission device allows the emergency center to make these adjustments in order to take into account local situations.  
         [0024]     After being started in block  500 , decision block  501  determines if there is a call origination. If the answer is no, block  503  performs normal processing before returning control back to decision block  501 . If the answer in decision block  501  is yes, decision block  502  determines if an emergency call is being placed. If the answer is no, decision block  505  performs normal processing before returning control back to decision block  501 . If the answer in decision block  502  is yes, block  504  sets up a call to the emergency center.  
         [0025]     Decision block  506  then determines if information has been received from the emergency center. In this context, decision block  506  is determining whether control information to control the emergency transmission device has been received. If the answer is no in decision block  506 , decision block  507  determines if a predefined time period has elapsed since the placing of the call to the emergency center. If the answer is no, control is returned back to decision block  506 . If the answer in decision block  507  is yes, block  508  activates the emergency transmission device and transfers control back to decision block  501 . In another embodiment of the invention, block  508  returns control back to decision block  506  so that the emergency center can at a later point in time adjust the frequency and power.  
         [0026]     Returning to decision block  506 , if the answer is yes in decision block  506 , decision block  509  determines if control information has been received from the emergency center to control the frequency of the emergency transmission device. If the answer is yes, block  511  adjusts and activates the emergency transmission device before returning control back to decision block  501 . Note, if the emergency transmission device had already been activated, block  511  merely adjusts the frequency. In another embodiment, block  511  does not return control back to decision block  501  but rather returns control back to decision block  506  so that the emergency center can make further adjustments. If the answer is no in decision block  509 , it is assumed that the emergency center is adjusting the power and control is transferred to block  512  to perform power adjustment on the transmission device before returning control back to decision block  501 . In another embodiment, block  512  does not return control back to decision block  501  but transfers control back to decision block  506 .  
         [0027]      FIG. 6  illustrates another embodiment of the invention.  FIG. 6  illustrates portable telecommunication terminals  600  and  609  connected to enterprise communication switching system  611 . Enterprise communication switching system  611  is interconnected to emergency center  612 . Portable telecommunication terminals  600  and  609  would be portable terminals using the Q.931 protocol or a proprietary digital protocol which are well known to those skilled in the art. Each of these portable telecommunication terminals has an emergency transmission device for use in accordance with the invention. The characteristic of these portable telecommunication terminals is that they can be plugged into enterprise communication switching system  611  at any time, and enterprise communication switching system  611  has no information concerning the physical location of these devices to a particular room. However, enterprise communication switching system  611  does know in general where the portable telecommunication terminal is connected.  
         [0028]     Audio and control information is received from enterprise communication switching system  611  via network interface  606 . Processor  603  performs all of the control functions of portable telecommunication terminal  600 . When processor  603  determines that the user is placing an emergency call, processor  603  performs the operations illustrated in the embodiments of  FIGS. 3 and 5 . Processor  603  performs these emergency call operations by executing emergency control routine  608  stored in memory  601 . Processor  603  performs these normal call operations by executing call control routine  607 .  
         [0029]     When the operations of devices  201 ,  408 , or  603  are implemented in software, as is shown in  FIGS. 3 and 5 , it should be noted that the software can be stored on any computer-readable medium for use by or in connection with any computer related system or method. In the context of this document, a computer-readable medium is an electronic, magnetic, optical, or other physical device or means that can contain or store a computer program for use by or in connection with a computer related system or method. Devices  201 ,  408 , or  603  can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “computer-readable medium” can be any means that can store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. For example, the computer-readable medium can be, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM) (electronic), a read-only memory (ROM) (electronic), an erasable programmable read-only memory (EPROM, EEPROM, or Flash memory) (electronic), an optical fiber (optical), and a portable compact disc read-only memory (CDROM) (optical). Note that the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured via optical scanning of the paper or other medium and then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and stored in a computer memory.  
         [0030]     In an alternative embodiment, where devices  201 ,  408 , or  603  are implemented in hardware, devices  201 ,  408 , or  603  can be implemented with any or a combination of the following technologies, which are each well known in the art: a discrete logic circuit(s) having logic gates for implementing logic functions upon data signals, an application specific integrated circuit (ASIC) having appropriate combinational logic gates, a programmable gate array(s) (PGA), a field programmable gate array (FPGA), etc.  
         [0031]     Of course, various changes and modification to the illustrated embodiments described above will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the following claims except insofar as limited by the prior art.