Abstract:
Methods and systems in which vocabulary recognition enables routing of analog transmissions over digital networks are provided. In one embodiment, a method ( 200 ) of delivering analog transmissions over a digital network includes receiving ( 208 ) an analog transmission including source identifying vocabulary associated with a source of the transmission, converting ( 210 ) the received analog transmission to a digitized transmission, analyzing ( 214 ) the digitized transmission to obtain the source identifying vocabulary therefrom, retrieving ( 220 ) routing information based on the source identifying vocabulary, buffering ( 212 ) the digitized transmission during the analyzing and retrieving steps, associating ( 222 ) the routing information with the buffered digitized transmission, and delivering ( 224 ) the buffered digitized transmission over the digital network according to the routing information associated therewith.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to accommodating analog voice transmissions in digital communication networks, and more particularly to routing and delivery of analog transmissions within digital communication networks. 
       BACKGROUND OF THE INVENTION 
       [0002]    At present, voice communications between airborne vehicles and ground stations such as, for example, between airplanes and air traffic control centers, is generally provided over analog wireless very high frequency (VHF) broadcasts using 25 KHz bandwidth assignments (25 KHz analog channels). Public safety and emergency response communication systems such as, for example, systems employed by police, fire, and emergency medical personnel and their associated dispatchers also often employ similar analog voice communication channels over a variety of frequencies. Given the large number of analog channels assigned for such uses, a substantial amount of spectrum is occupied and underutilized. 
         [0003]    Digital communication systems can provide enhanced capabilities as compared with existing analog air-to-ground/ground-to-air and public safety/emergency response communication systems such as, for example, an ability to accommodate more system users and improved transmission clarity and enhanced information transmission capabilities. Thus, there may be a desire to replace such analog systems with digital systems, but due to associated costs and other constraints it may not be practical to promptly end the use of such analog voice communication systems and require that digital voice communication systems immediately be employed by all users within a geographic region (e.g., a national or international air traffic control corridor, an air traffic control region, an airport, a county, or a city). In this regard, the ground control or public safety/emergency response dispatch communication system equipment may be upgraded to digital while many aircraft radios and public safety/emergency response personnel radios remain analog. This may create difficulties in directing analog voice transmissions from older analog equipment to the appropriate destination within digital ground control or public safety/emergency response dispatch networks. 
       SUMMARY OF THE INVENTION 
       [0004]    Accordingly, the present invention provides for the routing of analog transmissions over a digital network to desired destinations where source identifying vocabulary is included in the analog transmissions. The analog transmissions are processed to obtain the source identifying vocabulary therefrom and a destination on the digital network for the transmission is obtained using the source identifying vocabulary. One advantage provided by the present invention is that existing analog equipment can continue to be utilized while transitioning to an all digital communications system. Another advantage of the present invention is that information included in the analog transmission is utilized and no additional information regarding its source needs to be added to the transmission prior to transmitting it from the source. 
         [0005]    According to one aspect of the present invention, a method of delivering analog transmissions over a digital network includes receiving an analog transmission including source identifying vocabulary associated with a source of the transmission. The received analog transmission is converted to a digital format. The digitized transmission is analyzed to obtain the source identifying vocabulary therefrom. Routing information is retrieved based on the source identifying vocabulary. The digitized transmission is buffered during the steps of analyzing and retrieving, and the routing information is associated with the buffered digitized transmission. Thereafter, the buffered digitized transmission is delivered over the digital network according to the routing information associated therewith. 
         [0006]    The analog transmission may, for example, be received over a wireless communications channel such as a radio channel. The source of the analog transmission may, for example, be an individual onboard an aircraft (e.g., the pilot), or, for example, a public safety officer or an emergency responder (e.g., a police officer, firefighter, emergency medical technician). To obtain the source identifying vocabulary, the digitized transmission may be processed with a voice recognition algorithm. The voice recognition algorithm may be optimized to recognize a limited range of source identifying vocabulary corresponding with at least one standardized format for an activity such as, for example, where the activity is flying an aircraft, aircraft tail numbers and aircraft operator/flight number combinations. The routing information may comprise a network address that is associated with the buffered digitized transmission by concatenating it with the buffered digitized transmission. 
         [0007]    According to another aspect of the present invention, a communication system that delivers analog transmissions over a digital network includes an analog transmitter, an analog receiver, and an analog transmission processing unit. The analog transmitter is operable to transmit an analog transmission including source identifying vocabulary associated with a source of the transmission. The analog receiver is operable to receive the analog transmission. The analog transmission processing unit is communicatively coupled with the analog receiver and the digital network and is operable to perform a number of activities. In this regard, the analog transmission processing unit converts the received analog transmission to a digitized transmission, analyzes the digitized transmission to obtain the source identifying vocabulary therefrom, retrieves routing information based on the source identifying vocabulary, buffers the digitized transmission while analyzing the digitized transmission and retrieving the routing information, and associates the routing information with the buffered digitized transmission. In this manner, the digitized transmission corresponding with the transmitted and received analog transmission is prepared for routing and delivery to a destination via the digital network. 
         [0008]    The analog transmitter and analog receiver may, for example, be an analog radio transmitter and an analog radio receiver, respectively. The source of the analog transmission may, for example, be an individual onboard an aircraft (e.g., the pilot), or, for example, a public safety officer or an emergency responder (e.g., a police officer, firefighter, or emergency medical technician). The analog transmission processing unit may analyze the digitized transmission by implementing a voice recognition algorithm that processes the digitized transmission to recognize the source identifying vocabulary. In this regard, the voice recognition algorithm implemented by the analog transmission processing unit may be optimized to recognize a limited range of source identifying vocabulary corresponding with one or more standardized formats for an activity such as, for example, aircraft tail numbers and aircraft operator/flight number combinations. The routing information may be a network address, and the analog transmission processing unit may associate the routing information with the buffered digitized transmission by concatenating the network address with the buffered digitized transmission. 
         [0009]    These and other aspects and advantages of the present invention will be apparent upon review of the following Detailed Description when taken in conjunction with the accompanying figures. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0010]    For a more complete understanding of the present invention and further advantages thereof, reference is now made to the following Detailed Description, taken in conjunction with the drawings, in which: 
           [0011]      FIG. 1  shows one embodiment of communications system wherein analog transmissions are received and routed over a digital network; 
           [0012]      FIG. 2  shows one embodiment of a method of directing an analog transmission over a digital network; 
           [0013]      FIG. 3  shows another embodiment of communications system wherein analog transmissions are received and routed over a digital network; and 
           [0014]      FIG. 4  shows another embodiment of a method of directing an analog transmission over a digital network. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]      FIG. 1  is a schematic representation of one embodiment of communications system  100  in which analog transmissions are received and routed over a digital network. The system  100  includes several radios  102 A,  102 B,  102 C,  102 D. The system  100  is illustrated in the context of an air-traffic control application wherein the pilots of a plurality of aircraft  110  within an airspace communicate with ground controllers at an air traffic control center  108  via the system  100 . The system  100  may also be appropriate for use in other contexts as well including, for example, public safety officers or other emergency responders (e.g., police, fire, emergency medical) communicating with dispatchers at a public safety or emergency response coordination office (e.g., a dispatch center). Additionally, other embodiments of the system may include fewer than four radios or more than four radios, as well as multiple radios at the air traffic control center and additional air traffic control centers each including one or more radios. 
         [0016]    In the present embodiment, the radios  102 A- 102 D are configured to transmit and receive analog transmissions. In this regard, the radios  102 A- 102 D are coupled to respective antennas  112 A- 112 D. Analog transmission  120 A is generated by a transmitter portion  104 A of the radio  102 A at the air traffic control center  108  and is broadcast from the air traffic control center  108  via antenna  112 A. Analog transmission  120 A may include voice communications from an air traffic controller for the pilot or pilots of one or more of the airplanes  110 . In this regard, where the air traffic controller is using a digital air traffic control system, the air traffic controller&#39;s voice communications may initially be directed to transmitter portion  104 A in the form of a digital signal that then undergoes a digital-to-analog conversion prior to transmitter portion  104 A generating analog transmission  120 A corresponding therewith. Analog transmission  120 A is collected by the antennas  112 B- 112 D onboard the airplanes  110  and received by receiver portions  106 B- 106 D of the radios  102 B- 102 D onboard the airplanes  110 . Transmitter portions  104 B- 104 D of the radios  102 B- 102 D onboard the airplanes  110  generate respective analog transmissions  120 B- 120 D that are broadcast via respective antennas  112 B- 112 D onboard the airplanes  110 . Each analog transmission  120 B- 120 D may include voice communications from the pilot of each respective airplane  110  for one or more air traffic controllers responsible for directing air traffic with the airspace controlled by the air traffic control center  108 . Analog transmissions  120 B- 120 D are received by receiver portion  106 A of the radio  102 A at the ground control station  108 . 
         [0017]    The radio  102 A at the air traffic control center  110  may be part of an air traffic control system  130 . Air traffic control system  130  may include one or more air controller stations  132 , an analog transmission processing unit  134  and a digital network  136  connecting the air controller stations  132  with the analog transmission processing unit  134 . Digital network  136  may also connect the air traffic control center  108  with one or more additional air traffic control centers (not shown) and with other facilities (not shown). Radio  102 A is communicatively coupled with the analog transmission processing unit  134 . Air traffic control system  130  may also include a digital radio  138  that transmits and receives digital transmissions (not shown) via antenna  112 A (or a separate antenna) to and from one or more digital radios (not shown) onboard one or more additional airplanes (not shown) within the airspace controlled by the air traffic control center  108 . Digital radio  138  is also connected via digital network  136  to the air controller stations  132 . Digital transmissions received by the digital radio  138  may include digital information identifying the airplane from which such received transmissions originated. The identifying digital information included in a received digital transmission may be used by the digital network  136  to route such received digital transmissions via the digital network  136  to the appropriate air traffic control station  134  at which the air traffic controller currently responsible for the originating airplane is stationed. 
         [0018]    When receiver portion  106 A of radio  102 A receives one of the analog transmissions  120 B- 120 D from one of the airplanes  110 , the received analog transmission is directed to the analog transmission processing unit  134 . Analog transmission processing unit  134  converts the received analog transmission to a corresponding digital transmission and processes the corresponding digital transmission to obtain information included in the received analog transmission identifying the originating source of the transmission (e.g., identifying the airplane  110  from which the analog transmission was transmitted). The analog transmission processing unit  134  uses the source identifying information to determine which of the air controller stations  132  the corresponding digital transmission should be directed to via the digital network  136  (e.g., the air controller station  132  at which the air traffic controller responsible for the originating airplane  110  is seated). The corresponding digital transmission is routed through the digital network  136  to the appropriate air controller station  132 . 
         [0019]    Where communications between the air traffic control center  108  and the airplanes  110  are bi-directional, the analog transmission processing unit  134  may also receive a digital signal from any one of the air controller stations  132  via the digital network  136  and convert it to an analog signal for transmission by the analog transmitter portion  104 A of radio  102 A. 
         [0020]      FIG. 2  shows the steps involved in one embodiment of a method  200  of directing an analog transmitted voice communication from an aircraft pilot or the like to a ground controller via a digital network. The method  200  may be employed in connection with a system  100  such as shown in  FIG. 1 . The method  200  of  FIG. 2  can also be employed in connection with other communication systems where analog voice transmissions are to be received and routed via a digital network to a destination. 
         [0021]    The method  200  begins with receiving  202  a vocal communication from an individual such as, for example, the pilot of the aircraft. The vocal communication may be received  202  using, for example, a microphone. Although the vocal communication may be referred to herein as the pilot voice communication (or simply pilot voice), the vocal communication may in general be from any individual onboard the aircraft (e.g., the pilot, co-pilot, navigator, etc.). 
         [0022]    The pilot voice will typically include specific vocabulary (e.g., words, letters, numbers, or a combination thereof) identifying the aircraft. For example, the pilot&#39;s voice may include an aircraft tail number (e.g. “N12345”) or a combination of an aircraft operator name and flight number (e.g., “ABC Air 101”) as part of the communication. The vocabulary identifying the aircraft included in the pilot voice may take many forms other than an aircraft tail number or aircraft operator/flight number combination, but utilizing one or more standardized formats facilitates subsequent processing of the pilot voice communication for the source identifying vocabulary. The source identifying vocabulary may be anywhere in the pilot voice communication but will often occur at the beginning or end of the communication (e.g., “ABC Air 101 request permission to land” or “Acknowledge runway change N12345”). 
         [0023]    The pilot voice is modulated  204  onto a carrier signal and the modulated carrier signal is transmitted  206 . In the present embodiment, the modulated carrier signal is transmitted  206  wirelessly (e.g., typically as a radio signal although free-space optical or other wireless technologies may be utilized). The wirelessly transmitted pilot voice communication is an example of an analog voice transmission. 
         [0024]    The wireless analog voice transmission is received  208  and demodulated to obtain the pilot voice communication from the modulated carrier signal. In the present embodiment, the wireless analog voice transmission is received  208  and demodulated at a fixed location ground station. However, in other embodiments, it may be received and demodulated at a mobile ground platform (e.g., a truck, trailer or other moveable ground vehicle), a seaborne platform (e.g., a ship or submarine), an airborne platform (e.g., another aircraft) or a space platform (e.g., a satellite or space station). Thereafter, the demodulated pilot voice communication is converted  210  from an analog signal to a digital signal to obtain a digitized version of the pilot voice communication. The digitized pilot voice communication is an example of a digitized voice transmission corresponding with an analog voice transmission. In another embodiment, it is also possible to convert the received wireless analog voice transmission to digital and then digitally demodulate the pilot voice from the received and converted wireless transmission to obtain a digitized voice transmission. 
         [0025]    Once the digitized voice transmission is obtained, the digitized voice transmission is buffered  212  (e.g., in a digital memory) while a copy of the digitized voice transmission is analyzed  214 . In this regard, it is also possible to buffer a copy of the digitized voice transmission while the digitized voice transmission is analyzed  214 , and in general the digitized voice transmission and its copy are interchangeable since it is possible to make a perfect copy of the digitized voice transmission. Thus, the digitized voice transmission or its copy may be used interchangeably where appropriate. 
         [0026]    The digitized voice transmission is analyzed  214  to obtain the source identifying vocabulary from the pilot voice communication. In this regard, the digitized voice transmission may be processed  216  using a voice recognition algorithm. The voice recognition algorithm may, for example, be implemented in computer software executable by a computer processor. Voice recognition processing step  216  may also be referred to herein as vocabulary recognition processing step  216 . When processing  216  the digitized voice transmission using a voice recognition algorithm, anticipated characteristics of the pilot voice communication may be utilized to gain efficiencies in the processing  216 . In this regard, a limited vocabulary may be utilized corresponding with one or more standardized formats for the source identifying vocabulary. For example, the voice recognition algorithm may be programmed/trained to recognize only aircraft tail numbers or aircraft operator/flight number phrases from one or more lists of such information and all other words in the digitized voice transmission may be ignored. Further, the digitized voice transmission may be divided into a number of portions and processing  216  of the digitized voice transmission may begin with a first portion of the digitized voice transmission. If source identifying vocabulary is not found in the first portion, an end portion of the digitized transmission may analyzed, and if source identifying vocabulary is not found in the end portion, then one or more middle portions may be analyzed. Additionally, processing  216  of the digitized voice transmission may be ended once the source identifying vocabulary is obtained and the remainder of the digitized voice transmission ignored. 
         [0027]    Based on the recognized vocabulary from voice recognition processing step  216 , the aircraft identity is resolved  218 . In this regard, the identified vocabulary may be used to query one or more databases including vocabulary word and/or phrase entries cross-referenced with corresponding aircraft identifier entries. The vocabulary word and/or phrase entries included in the database(s) used in aircraft identity resolution step  218  may include the same aircraft tail numbers or aircraft operator/flight number phrases used as the limited vocabulary in the voice recognition processing step  216 . For example, where the recognized vocabulary is “N12345”, such recognized vocabulary may be cross-referenced with an aircraft identified as “ABC Airlines Flight Number 101”, or where the recognized vocabulary is “ABC Air 101”, such recognized vocabulary may also be cross-referenced with an aircraft identified as “ABC Airlines Flight Number 101”. 
         [0028]    After the aircraft identity is resolved, routing information is retrieved  220  based on the identity of the aircraft. The routing information indicates a destination for the digitized voice transmission buffered in buffering step  212 . In this regard, the routing information may be a network address within a digital network associated with a particular air traffic control station manned by a controller responsible for the identified aircraft. The routing information may be retrieved from one or more databases of network addresses that are cross-referenced against aircraft identities. The database(s) of network addresses and aircraft identifiers may be static over a given time period (e.g., digitized voice transmissions from a particular aircraft are always routed to the same station within the digital network) or dynamic over a given time period (e.g., digitized voice transmissions from a particular aircraft are routed to different destinations depending upon factors such as aircraft load on a given station within the digital network). 
         [0029]    After the routing information is retrieved, such routing information is associated  222  with the buffered digitized voice transmission. Routing information associating step  220  may also be referred to herein as digital message construct step  220 . In this regard, where the routing information is a network address associated with the destination, a digital message may be constructed that includes the routing information by concatenating the network address with the digitized voice transmission. For example, a string of one or more bits defining the network address may be added to the start or end of the string of bits comprising the digitized voice transmission. Where the digitized voice transmission is divided into a plurality of packets for transmission within a packet-switched digital network, the network address may be concatenated with each packet included in the digitized voice transmission. For example, a string of one or more bits defining the network address may be added to the start or end of each packet of bits comprising the digitized voice transmission. If not already included in the digitized voice transmission or one or more packets comprising the digitized voice transmission, error checking and/or parity bit(s) can also be added to the digitized voice transmission or one or more packets comprising the digitized voice transmission during the digital message construction step  222 . 
         [0030]    The buffered digitized voice transmission is routed  224  within digital network using the associated routing information. In this regard, the buffered digitized voice transmission or each packet comprising the buffered digitized voice transmission is routed to the destination retrieved in step  220 . To speed delivery of the buffered digitized voice transmission to the destination when the buffered digitized voice transmission is divided into a plurality of packets, routing  224  of early packets may be undertaken before association  222  of routing information with later packets is completed. 
         [0031]    When the digitized voice transmission reaches its destination, the digitized voice transmission is converted  226  into a voice signal. In this regard, the routing information (and any parity and/or error checking bits) may be stripped from the digitized voice transmission before converting  226  the digitized voice transmission. Where the digitized voice transmission comprises a number of packets, the packets may be buffered until all packets have been received before converting  226  or conversion  226  may begin on earlier packets before later packets have arrived. 
         [0032]    The voice signal is output  228  on an output device (e.g., a speaker). In this regard, the voice signal is an analog representation of the digitized voice transmission which is in turn a digital representation of the pilot&#39;s vocal communication. Thus, in addition to the words included in the pilot&#39;s voice communication, the voice signal that is output  228  includes original features of the pilot voice such as accent, pitch, tone, inflection, and cadence. Although possible to generate a synthesized voice in place of the voice signal, outputting  228  a non-synthesized voice signal is advantageous since the voice signal that is output includes such additional features and is therefore a more accurate representation of the original pilot&#39;s voice communication. 
         [0033]      FIG. 3  is a schematic representation of another communications system  300  configured for receiving and routing analog transmissions in a digital network. The system  300  includes several analog radios  302 A,  302 B,  302 C,  302 D. The system  300  is illustrated in the context of public safety/emergency responder communications. In this regard, one of the radios  302 A is located at, for example, a dispatch center  308  and three of the radios  302 B,  302 C,  302 D are associated with, for example, individual public safety/emergency responder personnel  310 . Dispatch center  308  may, for example, be fixed location or mobile (e.g., within a mobile command vehicle). Radios  302 B- 302 D may, for example, be handheld radios carried by police officers, fire fighters or emergency medical technicians and/or radios installed in police cruisers, fire trucks, ambulances or the like. Radio  302 A may be referred to herein as a dispatch radio  302 A, and radios  302 B- 302 D may be referred to herein as responder radios  302 B- 302 D. Other embodiments of the system may include more than the one dispatch radio  302 A and fewer or more than the three responder radios  302 B- 302 D. 
         [0034]    In the present embodiment, radios  302 A- 302 D, including the transmitter  304 A- 304 D and receiver  306 A- 306 D portions thereof, are configured to transmit and receive analog transmissions. In this regard, the radios  302 A- 302 D are coupled to respective antennas  312 A- 312 D. Analog transmission  320 A is generated by the transmitter portion  304 A of the dispatch radio  302 A and is broadcast from the dispatch center  308  via antenna  312 A. Analog transmission  320 A may include voice communications from a dispatcher or other personnel at the dispatch center  308  for individual public safety/emergency responder personnel. In this regard, where the dispatcher is using a digital dispatch communication system, the dispatcher&#39;s voice communications may initially be directed to transmitter portion  304 A in the form of a digital signal that then undergoes a digital-to-analog conversion prior to transmitter portion  304 A generating analog transmission  320 A corresponding therewith. Analog transmission  302 A is collected by the antennas  312 B- 312 D coupled to the responder radios  302 B- 302 D and received by the receiver portions  306 B- 306 D thereof. 
         [0035]    The transmitter portions  304 B- 304 D of the responder radios  302 B- 302 D generate respective analog transmissions  320 B- 320 D that are broadcast via respective antennas  312 B- 312 D coupled thereto. Each analog transmission  320 B- 320 D may include respective voice communications from respective public safety/emergency responder personnel  310  for one or more dispatchers or other personnel at the dispatch center  308 . 
         [0036]    The dispatch radio  302 A may be part of a public safety/emergency response dispatch system  330 . Public safety/emergency response dispatch system  330  may include one or more dispatcher stations  332 , an analog transmission processing unit  334 , and a digital network  336  connecting dispatcher stations  332  with the analog transmission processing unit  334 . Digital network  336  may also connect the dispatch center  308  with one or more additional dispatch centers (not shown), and with other facilities (not shown). Dispatch radio  302 A is communicatively coupled with the analog transmission processing unit  334 . 
         [0037]    Public safety/emergency response dispatch system  330  may also include a digital dispatch radio  338  that transmits and receives digital transmissions (not shown) via antenna  312 A (or a separate antenna) to and from one or more digital responder radios (not shown) utilized by one or more public safety/emergency responder personnel. The digital dispatch radio  338  may also be connected via digital network  336  to the dispatcher stations  332 . Digital transmissions received by the digital dispatch radio  338  may include digital information identifying the originating digital responder radio source of such received digital transmissions. The source identifying digital information included in a received digital transmission may be used by the digital network  336  to route such received digital transmission via the digital network  336  to the appropriate dispatcher station  332  at which a dispatcher or other personnel responsible for communicating with the individual public safety/emergency responder personnel operating the originating digital responder radio source. 
         [0038]    When receiver portion  306 A of the dispatch radio  302 A receives one of the analog transmissions  320 B- 320 D from one of the responder radios  302 B- 302 D, the received analog transmission is directed to the analog transmission processing unit  334  coupled to the dispatch radio  302 A. The analog transmission processing units  334  converts the analog transmission received thereby to a corresponding digital transmission and processes the corresponding digital transmission to obtain information included in the received analog transmission identifying the originating source of the transmission (e.g., identifying the individual public safety/emergency responder personnel operating the responder radio  302 B- 302 D from which the analog transmission was transmitted). The analog transmission processing unit  334  uses the source identifying information to determine which of the dispatcher stations  332  the corresponding digital transmission should be directed to via the digital network  336  (e.g., to the dispatcher station  332  at which the dispatcher responsible for communicating with the public safety/emergency responder personnel  310  is located). The corresponding digital transmission is routed through the digital network  336  to the appropriate dispatcher station  136 . In this manner, the appropriate dispatchers receive voice communications from the public safety/emergency responder personnel. 
         [0039]    Where communications between the dispatch system  330  and the public safety/emergency responder personnel  310  are bi-directional, the analog transmission processing unit  334  may also receive a digital signal from any one of the dispatch stations  332  via the digital network  336  and convert it to an analog signal for transmission by the analog transmitter portion  304 A of dispatch radio  302 A. 
         [0040]      FIG. 4  shows the steps involved in one embodiment of a method  400  of directing an analog transmitted voice communication from an individual such as, for example, a public safety officer or an emergency responder to another individual such as, for example, a dispatcher via a digital network. The method  400  may be employed in connection with a public safety/emergency response communication system  200  such as shown in  FIG. 2 . The method  400  of  FIG. 4  can also be employed in connection with other communication systems where analog voice transmissions are to be received and routed via a digital network to a destination. The method  400  of  FIG. 4  represents a more generalized application of the method illustrated in  FIG. 2 . 
         [0041]    The method  400  begins with receiving  402  a voice communication from the individual using, for example, a microphone. The voice communication may include vocabulary (e.g., words, letters, numbers, or a combination thereof) identifying the speaker. For example, a police officer, fire fighter, or emergency medical technician may include his or her name and/or a vehicle number as part of their communication. Although the vocabulary identifying the individual included in the voice communication may take many forms, persuading users to adopt one or more standardized formats in advance of implementing the method  400  facilitates subsequent processing of the voice communication for the source identifying vocabulary. The source identifying vocabulary may be anywhere in the voice communication but will often occur at the beginning or end of the communication (e.g., “Engine 1 responding” or “Proceeding to crime scene Smith over”). 
         [0042]    The voice communication is modulated  404  onto a carrier signal and the modulated carrier signal is transmitted  406 . In the present embodiment, the modulated carrier signal is transmitted  406  wirelessly (e.g., typically as a radio signal although free-space optical or other wireless technologies may be utilized). In other embodiments, the modulated carrier signal may be transmitted using a non-wireless path or even a combination of wireless and non-wireless paths. 
         [0043]    The wireless analog voice transmission is received  408  and demodulated to obtain the voice communication from the modulated carrier signal. Thereafter, the demodulated voice communication is converted  410  from an analog signal to a digital signal to obtain a digitized version of the voice communication. The digitized voice communication corresponds with the original analog voice transmission. In another embodiment, it is also possible to convert the received wireless analog voice transmission to digital and then digitally demodulate the voice communication from the received and converted wireless transmission to obtain a digitized voice transmission corresponding with the original analog voice transmission. 
         [0044]    Once the digitized voice transmission is obtained, the digitized voice transmission is buffered  412  while a copy of the digitized voice transmission is analyzed  414 . In this regard, it is also possible to buffer a copy of the digitized voice transmission while the digitized voice transmission is analyzed  414 , and in general the digitized voice transmission and its copy are interchangeable since it is possible to make a perfect copy of the digitized voice transmission. Thus, the digitized voice transmission or its copy may be used interchangeably where appropriate. 
         [0045]    The digitized voice transmission is analyzed  414  to obtain the source identifying vocabulary from the voice communication. In this regard, the digitized voice transmission may be processed  416  using a voice recognition algorithm. Voice recognition processing step  416  may also be referred to herein as vocabulary recognition processing step  416 . When processing  416  the digitized voice transmission using a voice recognition algorithm, anticipated characteristics of the voice communication may be utilized to gain efficiencies in the processing  416 . In this regard, a limited vocabulary may be utilized corresponding with one or more standardized formats for the source identifying vocabulary. For example, the voice recognition algorithm may be programmed/trained to recognize only the names of police officers, fire fighters, emergency medical responders and their associated vehicle numbers working in a geographic region covered by a communication system in which the method  400  is implemented. Further, the digitized voice transmission may be divided into a number of portions and processing  416  of the digitized voice transmission may begin with a first portion of the digitized voice transmission. If source identifying vocabulary is not found in the first portion, an end portion of the digitized transmission may analyzed, and if source identifying vocabulary is not found in the end portion, then one or more middle portions may be analyzed. Additionally, processing  316  of the digitized voice transmission may be ended once the source identifying vocabulary is obtained and the remainder of the digitized voice transmission ignored. 
         [0046]    Based on the recognized vocabulary from voice recognition processing step  416 , the identity of the source of the voice transmission is resolved  418 . In this regard, the source identified vocabulary may be used to query one or more databases including vocabulary word and/or phrase entries cross-referenced against corresponding individual source name entries. The vocabulary word and/or phrase entries included in the database(s) used in source identity resolution step  418  may include the same vocabulary used as the limited vocabulary in the voice recognition processing step  416 . 
         [0047]    After the identity of the source is resolved, routing information is retrieved  420  based on the source identity. The routing information indicates a destination for the digitized voice transmission buffered in buffering step  412 . In this regard, the routing information may be a network address within a digital network connecting a receiver of the wireless analog transmission with an output device associated with one or more individuals to whom the voice communication is directed. The routing information may be retrieved from one or more databases of network addresses that are associated with output devices connected to the digital network that are cross-referenced against corresponding source identities. The database(s) of network addresses and source identities may be static over a given time period (e.g., digitized voice transmissions from a particular source are always routed to the same output device station within the digital network) or dynamic over a given time period (e.g., digitized voice transmissions from a particular source are routed to different destinations). 
         [0048]    After the routing information is retrieved, such routing information is associated  422  with the buffered digitized voice transmission. Routing information associating step  420  may also be referred to herein as digital message construct step  420 . In this regard, where the routing information is a network address associated with the destination, a digital message may be constructed that includes the routing information by concatenating the network address with the digitized voice transmission. For example, a string of one or more bits defining the network address may be added to the start or end of the string of bits comprising the digitized voice transmission. Where the digitized voice transmission is divided into a plurality of packets for transmission within a packet-switched digital network, the network address may be concatenated with each packet included in the digitized voice transmission. For example, a string of one or more bits defining the network address may be added to the start or end of each packet of bits comprising the digitized voice transmission. If not already included in the digitized voice transmission or one or more packets comprising the digitized voice transmission, error checking and/or parity bit(s) can also be added to the digitized voice transmission or one or more packets comprising the digitized voice transmission in the digital message construction step  422 . 
         [0049]    The buffered digitized voice transmission is routed  424  within digital network using the associated routing information. In this regard, the buffered digitized voice transmission or each packet comprising the buffered digitized voice transmission is routed to the destination retrieved in step  420 . To speed delivery of the buffered digitized voice transmission to the destination when the buffered digitized voice transmission is divided into a plurality of packets, routing  424  of early packets may be undertaken before association  422  of routing information with later packets is completed. 
         [0050]    When the digitized voice transmission reaches its destination, the digitized voice transmission is converted  426  into a voice signal. In this regard, the routing information (and any parity and/or error checking bits) may be stripped from the digitized voice transmission before converting  426  the digitized voice transmission. Where the digitized voice transmission comprises a number of packets, the packets may be buffered until all packets have been received before converting  426  or conversion  426  may begin on earlier packets before later packets have arrived. 
         [0051]    The voice signal is output  428  on an output device (e.g., a speaker). In this regard, the voice signal is an analog representation of the digitized voice transmission which is in turn a digital representation of the original vocal communication. Thus, in addition to the words included in the voice communication, the voice signal that is output  428  includes original features of the speaker&#39;s voice such as accent, pitch, tone, inflection, and cadence. Although possible to generate a synthesized voice in place of the voice signal, outputting  428  a non-synthesized voice signal is advantageous since the voice signal that is output includes such additional features and is therefore a more accurate representation of the original speaker&#39;s voice communication. 
         [0052]    While various embodiments of the present invention have been described in detail, further modifications and adaptations of the invention may occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention.