Abstract:
Described is a communication device which includes a receiver receiving a multicast communication including audio data and identification data identifying an initiator of the multicast communication, a memory, an audio output, a processor processing the multicast communication, sending the processed audio data to the audio output to be played to a user, sending the identification data to the memory to be stored and initiating a unicast communication with the initiator based on the identification data and a transmitter transmitting the unicast communication to the initiator.

Description:
PRIORITY CLAIM 
     This application claims the priority to the U.S. Provisional Application Ser. No. 60/884,722, entitled “System and Method of Switching from Multicast to Unicast Calls,” filed Jan. 12, 2007. The specification of the above-identified application is incorporated in its entirety herewith by reference 
    
    
     FIELD OF INVENTION 
     The present invention related to a system and method of switching from multicast to unicast calls. 
     BACKGROUND 
     A wireless mobile device may operate as a digital walkie-talkie over Internet Protocol (IP) and/or Voice Over Internet Protocol (VOIP). The digital walkie-talkie over IP operates on the basis of a half duplex communication system where, although two-way communication may be performed, only one party may send a signal at a time. A half duplex communication is multicast over a communication network so that one party may transmit the same signal to a plurality of recipients. 
     A VOIP communication utilizes a full duplex system, which is unicast so signals are only sent to a single destination, thereby increasing communication privacy. Wireless mobile devices are now equipped with the option to be able to communicate using both half duplex and full duplex communication systems. 
     SUMMARY OF THE INVENTION 
     A method for receiving a multicast communication including data identifying an initiator of the multicast communication, storing the data identifying the initiator and initiating a unicast communication with the initiator using the data identifying the initiator. 
     A communication device having a receiver receiving a multicast communication including audio data and identification data identifying an initiator of the multicast communication, a memory, an audio output, a processor processing the multicast communication, sending the processed audio data to the audio output to be played to a user, sending the identification data to the memory to be stored and initiating a unicast communication with the initiator based on the identification data and a transmitter transmitting the unicast communication to the initiator. 
     A method for receiving a multicast communication including audio data and identification data identifying an initiator of the multicast communication, processing the identification data and forwarding the audio data to a plurality of devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
         FIG. 1  shows a first exemplary system for placement of a unicast call according to an exemplary embodiment of the present invention. 
         FIG. 2  shows a first exemplary method for the first system of  FIG. 1  according to the present invention. 
         FIG. 3  shows a second exemplary system for placement of a unicast call according to second exemplary embodiment of the present invention. 
         FIG. 4  shows a second exemplary method for the second system of  FIG. 3  according to the present invention 
         FIG. 5  shows a third exemplary system for placement of a unicast call according to a third exemplary embodiment of the present invention. 
         FIG. 6  shows a third exemplary method for the third system of  FIG. 5  according to the present invention. 
         FIG. 7  shows a fourth exemplary system for placement of a unicast call according to a fourth exemplary embodiment of the present invention. 
         FIG. 8  shows a fourth exemplary method for the fourth system of  FIG. 7  according to the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention may be further understood with reference to the following description and the appended drawings. The present invention provides a method and system for facilitating the transition from half duplex to full duplex communications by the users of wireless mobile devices (e.g., a cell phone, a personal digital assistant, a walkie-talkie, a two-way radio, a data acquisition device, etc.). The exemplary embodiment may be implemented with either a single or a plurality of servers and/or routers and/or or any other type of network device that may perform the features of the server described herein. 
     The exemplary embodiments of the present invention utilize a user-friendly interface allowing mobile device users the option to switch from half duplex to full duplex communications with a minimal use of controls. In doing so, the exemplary embodiments employ a walkie-talkie transmission log to record incoming half-duplex communications on a mobile device. As will be described more fully below, the exemplary embodiments provide a number of methods by which the walkie-talkie transmission log is created and also a number of methods by which the walkie-talkie transmission log is retained on and/or relayed to the wireless mobile device(s). 
     A mobile device may operate as a digital walkie-talkie over Internet Protocol (IP) and/or Voice Over Internet Protocol (VOIP). The digital walkie-talkie over IP may operate on the basis of a half duplex communication system where, although two-way communication may be performed, only one party may send a signal at a time. Once a party begins receiving a signal, it must wait for the transmitter to stop transmitting before replying. A half duplex communication is multicast over a communication network so that one party may transmit the same signal to a plurality of recipients belonging to a particular multicast group. For example, an audio signal being sent to a particular multicast group may be multicast to every individual belonging to the group. 
     A VOIP communication utilizes a full duplex system, which allows simultaneous communication in both directions. The VOIP communication is unicast so signals are only sent to a single destination. A user may desire to switch from a half duplex to a full duplex communication system to increase communication privacy. Both of the aforementioned systems operate using the same basic infrastructure (e.g., both send digital signals through a server). However, those skilled in the art will understand that there are many different types of infrastructures that support these types of voice communications. As such, mobile devices are equipped with the option to be able to communicate using both half duplex and full duplex communication systems. 
       FIG. 1  shows a first system according to an exemplary embodiment of the present invention. Initially, a mobile device  105  may begin a half duplex communication using the walkie-talkie feature to multicast audio data  130  to a plurality of receivers  115 ,  125  and  135 . When the mobile device  105  multicasts the audio signal  130 , the phone extension  150  and the name  160  associated with the mobile device  105  may also be included in the transmission. Those skilled in the art will understand that, as this is a digital walkie-talkie over IP system, the aforementioned data (e.g., audio signal  130 , phone extension  150  and name  160 ) may be embedded in a multicast packet  111 . When the mobile devices  115 ,  125  and  135  receive the multicast transmission, they may output the audio data  130  via a speaker. The phone extension  150  and the name  160  associated with the mobile device that transmitted the information (e.g., mobile device  105 ) may be cached. The mobile devices  115 ,  125  and  135  may have any type of volatile and/or non-volatile memory to store or cache the data. The data may be stored, for example, in a database in the form of the walkie-talkie transmission logs  116 ,  126  and  136  for mobile devices  115 ,  125  and  135 , respectively. The walkie-talkie transmission logs  116 ,  126  and  136  may be a list of received data from different multicast transmissions. These lists may include a certain predefined number of previously received transmissions or may include previously received transmissions for a predetermined period of time. 
     Thus, when the users of mobile device  115 ,  125  or  135  desire to call the mobile device  105  using a full duplex communication, the walkie-talkie transmission logs  116 ,  126  and  136 , respectively, may be used to simplify this transition. For example, because the walkie-talkie transmission log  116  has the phone extension  150  and name  160  information for the recently received multicast transmissions, the mobile device  115  may allow quick access to this walkie-talkie transmission log  116  to quickly place the full duplex call to the mobile device  105 . 
       FIG. 2  shows a first exemplary method of the first system of  FIG. 1 . The method of  FIG. 2  will be described with reference to the system of  FIG. 1 . In step  200 , the mobile device  105  initiates a half duplex communication to a plurality of receiving mobile devices. In steps  201 - 203 , data included in the half duplex communication is sent to the plurality of receiving devices. The data includes the audio signal  130  (step  201 ), the name  160  (step  202 ) and the phone extension  150  (step  203 ). 
     In step  205 , the receiving mobile devices, including mobile devices  115 ,  125  and  135  cache the non-audio data (e.g., name  160  and phone extension  150 ) into respective walkie-talkie transmission logs  116 ,  126  and  136 . 
     In step  207 , if half duplex walkie-talkie transmissions continue to be made, the process will loop back to step  200  where the steps  200 - 205  will be performed for each walkie-talkie transmission. Those skilled in the art will understand that if a receiving device receives multiple transmissions from the same transmitting device, i.e., the same phone number and name data in successive transmissions, the receiving device may not store each instance of the data in the walkie-talkie transmission log. 
     If the walkie-talkie transmission is ended in step  207 , the method continues to step  208  to determine if the user desires to place a full duplex call. If no call is made, the process ends with the data stored in the walkie-talkie transmission log for further use. However, if the user desires to make a full duplex call, the mobile devices  115 ,  125  or  135  may display the walkie-talkie transmission log in step  209 . From these walkie-talkie transmission logs, a selection may be made based on the name and/or the phone number to place the full duplex call in step  210 . 
     The walkie-talkie transmission logs may be displayed on the mobile device in various manners. For example, a user interface of the mobile device may include a callback selection button (hard or soft key). When the callback function is selected, the mobile device may display the walkie-talkie transmission log in a list form, allowing the user to scroll through the list in reverse chronological order and select the other user to call. In another exemplary embodiment, the walkie-talkie transmission logs may be selectable from the same initial menu. In yet another exemplary embodiment, each time a multicast transmission is received, the mobile device may display the data (e.g., phone number, name, etc.) with a list of options such as place a call to this user, cancel, show other recently received walkie-talkie communications, etc. 
       FIG. 3  shows a second exemplary system according to an exemplary embodiment of the present invention. As with the above-described exemplary embodiment, the mobile device  305  may initiate a half duplex communication using the walkie-talkie feature to a plurality of receivers. This communication may be processed and/or routed via a server  310  (or any other type of network device that may perform the features of the server described below). The multicast transmission from the mobile device  305  may include the audio signal  330  and the IP address  340  of the mobile device  305 . The server  310  may include a database  320  that may include a correlation of phone extensions  350  and/or names  360  with IP addresses  340 . Those skilled in the art will understand that using a database to store the correlation is only exemplary. Other storage mechanisms, for example, tables, arrays, etc., may also be used. Thus, when the server  310  receives the multicast communication from mobile device  305  having the audio signal  330  and the IP address  340 , the server  310  may look-up the correlation in the database  320 . The server  310  may then insert the corresponding phone extension  350  and/or name  360  into the multicast packets  333  that are forwarded to the members of the multicast group, including mobile devices  315 ,  325  and  335 . The multicast transmission leaving the server  310  will include the audio signal  330 , the phone extension  350  and/or the name  360 . When received by the mobile devices  315 ,  325  and  335 , the phone extension  350  and the name  360  may be cached in the walkie-talkie transmission logs  316 ,  326  and  336 . The walkie-talkie transmission logs  316 ,  326  and  336  may be used in the same manner as described above for the walkie-talkie transmission logs  106 ,  116 ,  126  and  136  as described with reference to  FIGS. 1-2 . 
       FIG. 4  shows a second exemplary method for the system of  FIG. 3 . The method of  FIG. 4  will be described with reference to the system of  FIG. 3 . In step  400 , the mobile device  305  initiates a half duplex communication to a plurality of receiving mobile devices. In steps  401 - 402 , data for the half duplex communication is sent to the server. The data includes the audio signal  330  (step  401 ) and the IP address  340  (step  402 ) for mobile device  305 . 
     In step  403 , the server  310  correlates the received IP address  340  to the name  360  and/or phone extension  350  using the database  320 . The server  310  then transmits this information, along with the audio signal  330 , to the multicast recipients in steps  405 - 407 . The transmitted data includes the audio signal  330  (step  405 ), the name  360  (step  406 ) and the phone extension  350  (step  407 ). The aforementioned data may be sent as part of a multicast data packet  333 . 
     In step  408 , the receiving mobile devices may cache the received non-audio data into walkie-talkie transmission logs  316 ,  326  and  336 . In step  409 , if half duplex walkie-talkie transmissions continue to be made, the process will loop back to step  400  where the steps  400 - 408  will be performed for each walkie-talkie transmission. Those skilled in the art will understand that if a receiving device receives multiple transmissions from the same transmitting device, i.e., the same phone number and name data in successive transmissions, the receiving device may not store each instance of the data in the walkie-talkie transmission log. For example, if a mobile device has the memory capacity to record only a predetermined number of transmissions, wherein newer transmissions replace older transmissions in chronological order, multiple transmissions from the same user may not override transmissions from other users. 
     If the walkie-talkie transmission is ended in step  409 , the method continues to step  410  to determine if the user desires to place a full duplex call. If no call is made, the process ends with the data stored in the walkie-talkie transmission log for further use. However, if the user desires to make a full duplex call, the mobile devices  315 ,  325  or  335  may display the walkie-talkie transmission logs  316 ,  326  and  336  respectively in step  411 . The user of the mobile device may then reference the name and/or the phone extension included therein to place the full duplex call in step  412 . 
       FIG. 5  shows a third exemplary system according to an exemplary embodiment of the present invention. As with the above-described exemplary embodiments, the mobile device  505  may initiate a half duplex communication using the walkie-talkie feature. This communication may be processed and/or routed via a server  510  (or any other type of network device that may perform the features of the server described below). 
     In the exemplary embodiment of  FIG. 3  noted above, the server  310  may include a database that includes a correlation of phone extensions and/or names with IP addresses so a correlation may be made for the phone extensions and/or names for each of the multicast transmissions. In the exemplary embodiment of  FIG. 5 , the multicast transmission from the mobile device  505  includes the audio signal  530 , the phone extension data  550  and/or the name  560 . Thus, in this exemplary embodiment, the server  510  would not require the correlation database because the phone extension  550  and name  560  would be included in the multicast transmission. 
     Additionally, the server  510  may store the information concerning the multicast transmission (e.g., phone extension  550  and name  560 ) as a group-specific walkie-talkie transmission log  521  in the database  520 . As additional transmissions are sent to the multicast group in question, the server  510  may store this data to the walkie-talkie transmission log  521  in the database  520 . The database  520  may store all half duplex audio transmissions across a network according to the multicast group being transmitted to. The server  510  may then forward audio data  530  and the walkie-talkie transmission log  521  to the mobile devices  515 ,  525  and  535  that are the recipients in the particular multicast group. The mobile devices  515 ,  525  and  535  may then cache the data from the walkie-talkie transmissions log  521  internally as walkie-talkie transmission logs  516 ,  526  and  536 , respectively. Those skilled in the art will understand that the server  510  may not send the entire log after every transmission, but may merely send an update to indicate the last transmission to each multicast group. The walkie-talkie transmission logs  516 ,  526  and  536  may be used in the same manner as described above for the walkie-talkie transmission logs  116 ,  126  and  136  as described with reference to  FIGS. 1-2 . 
       FIG. 6  shows a third exemplary method for the third system of  FIG. 5 . The method of  FIG. 6  will be described with reference to the system of  FIG. 5 . In step  600 , the mobile device  505  initiates a half duplex communication to a plurality of receiving mobile devices. In steps  601 - 603 , data for the half duplex communication is sent to the server. The data includes the audio signal  530  (step  601 ), phone extension  550  (step  602 ) and name  560  (step  603 ) for mobile device  505 . 
     In step  604 , the audio signal is sent to the receiving devices  515 ,  525  and  535 . At the same time, the database  520  retains a log of the transmissions sent to a particular multicast group (step  605 ). Once this data has been saved, the database  520  enables the server  510  to transmit the data for the walkie-talkie transmission logs  516 ,  526  and  536  to the receiving mobile devices  515 ,  525  and  535  respectively (step  606 ). In step  607 , the receiving mobile devices may cache the data received for the walkie-talkie transmission logs  516 ,  526  and  536 . 
     In step  608 , if half duplex walkie-talkie transmissions continue to be made, the process will loop back to step  600  where the steps  600 - 607  will be performed for each walkie-talkie transmission. Those skilled in the art will understand that if a receiving device receives multiple transmissions from the same transmitting device, i.e., the same phone number and name data in successive transmissions, the receiving device may not store each instance of the data in the walkie-talkie transmission log. 
     Conversely, if the walkie-talkie transmission is ended in step  608 , the method continues to step  609  to determine if the user desires to place a full duplex call. If no call is made, the process ends with the data stored in the walkie-talkie transmission log for further use. However, if the user desires to make a full duplex call, the mobile devices  515 ,  525  or  535  may display the walkie-talkie transmission logs  516 ,  526  and  536  respectively in step  610 . The users may place the full duplex call in step  611  by selecting the name  560  and/or the phone extension  550  of the recipient. 
     It should be noted that this exemplary embodiment may also incorporate the correlation database as discussed above with reference to  FIG. 3 . It will be apparent to those skilled in the art as to how to implement the correlation database based on the above description of this exemplary embodiment and the correlation database. 
       FIG. 7  shows a fourth exemplary system according to an exemplary embodiment of the present invention. The embodiment of  FIG. 7  may operate in the same manner as the embodiment described with respect to  FIG. 5 . The difference is that, in this embodiment, the server  710  will not send the walkie-talkie transmission logs  716 ,  726  and  736  to the mobile devices  715 ,  725  and  735 , respectively, until requested to do so. Once the audio signal  730  is sent to the server  710  along with the phone extension  750  and the name  760  of the mobile device  705 , the database may record the aforementioned non-audio data in a multicast group specific walkie-talkie transmission log  721 . After receipt of the audio signal  730 , the mobile device  715 ,  725  or  735  may send a transmission log request  717 ,  727  or  737 , respectively, to the server  710  requesting the walkie-talkie transmission log for a particular multicast group. This transmission log requests  717 ,  727  and  737  may be sent via a plurality of options, e.g., by selecting a callback option on the mobile device  715 ,  725  or  735 , via a text message prompt sent by a mobile device, via selection of a log request option which may automatically be displayed upon termination of a half-duplex transmission, etc. After receiving the request, the server  710  may retrieve the multicast group specific walkie-talkie transmission log  721  from the database  720  and send the walkie-talkie transmission log  721  to the mobile device  715 ,  725  and  735 . The mobile devices  715 ,  725  and  735  may then cache the received data into respective walkie-talkie transmission logs  716 ,  726  and  736 , which may be used in the same manner as described above for the walkie-talkie transmission logs  116 ,  126  and  136  as described with reference to  FIGS. 1-2 . 
       FIG. 8  shows an exemplary method for the system of  FIG. 7 . The method of  FIG. 8  will be described with reference to the system of  FIG. 7 . In step  800 , the mobile device  705  initiates a half duplex communication to a plurality of receiving mobile devices. In steps  801 - 803 , data for the half duplex communication is sent to the server. The data includes the audio signal  730  (step  801 , phone extension  750  (step  802 ) and name  760  (step  803 ) for mobile device  705 . 
     In step  804 , the audio signal is multicast to the receiving devices  715 ,  725  and  735 . In step  805 , if half duplex walkie-talkie transmissions continue to be made, the process will loop back to step  800  where the steps  800 - 805  will be performed for each walkie-talkie transmission. 
     Conversely, if the walkie-talkie transmission is ended in step  805 , the method continues to step  806  to determine if the user desires to place a full duplex call. If no call is made, the process ends. However, if a full duplex call is to be placed at a later time to a recent half-duplex transmission recipient, the mobile device may be directed to steps  807 - 810 , as detailed below. 
     If the user desires to make a full duplex call, the mobile devices  715 ,  725  or  735  may send walkie-talkie transmission logs requests  717 ,  727  and  737  respectively in step  807 . Upon receipt of these requests, the server  710  may transmit the walkie-talkie transmission log  721  to the mobile devices  715 ,  725  and  735  (step  808 ). Upon receipt, the receiving mobile devices  715 ,  725  and  735  may cache the walkie-talkie transmission log  721 . The mobile devices  715 ,  725  and  735  may now reference their respective walkie-talkie transmission logs  716 ,  726  and  736  to place the full duplex call in step  811 . 
     In yet another exemplary embodiment, the server may listen to all walkie-talkie multicast groups and record the device that initiates the transmissions, thereby creating a walkie-talkie transmission log for each multicast group. The devices may then request multicast group logs from the server on an as-needed basis. 
     Those skilled in the art will understand that the described exemplary embodiments of the present invention may be altered without departing from the spirit or scope of the invention. Thus, it is to be understood that these embodiments have been described in an exemplary manner and are not intended to limit the scope of the invention which is intended to cover all modifications and variations of this invention that come within the scope of the appended claims and their equivalents.