Abstract:
A method for push to talk over cellular (PoC) operation is provided. The method is applied in a cellular phone with a PoC button associated. The method comprises: (A) detecting the PoC button has been pressed and released a first time, wherein the time length the PoC button has been pressed does not exceed a first time limit; (B) detecting the PoC button has been pressed and released a second time, wherein the time length the PoC button has been pressed the second time does not exceed the first time limit, wherein the time difference between the first and second times of releasing the PoC button does not exceed a second time limit; (C) assigning the PoC button a pressed button status when the PoC button has been pressed and then released the second time; (D) sending a floor grant request to establish an outward voice communication; (E) receiving a floor grant message; and (F) establishing and maintaining the outward voice communication wherein the PoC button is associated with the pressed button status.

Description:
BACKGROUND  
       [0001]     The invention relates to a cellular phone and in particular a cellular phone that provides a push to talk over cellular (PoC) service.  
         [0002]     Push to talk over cellular (PoC) introduces a direct one-to-one and one-to-many voice communication service to the cellular network. PoC provides a walkie-talkie-like service. The most powerful feature of PoC is a group talk service that allows many users to join the same session. PoC is based on half duplex VOIP (voice over IP) technology over the second generation GSM/GPRS network. A push to talk call is a one-way communication: while one person speaks, the other(s) listen. Typically, a cellular phone supporting a PoC service has a dedicated PoC button. A PoC service provides instant voice connectivity to the party on the other end. When a user wants to talk, he presses and holds down a PoC button on the phone, or holds down the mouse button or space bar on a computer. Letting go of the button allows the other person to talk. The turns to speak are granted by pressing a push to talk button on a first come, first serve basis. Thus, PoC requires a control mechanism to control the turns to speak among a plurality of users within a preset group. This control mechanism defines a “floor” (i.e., the turn to speak). The user gains the turn to speak when he or she owns the floor.  
         [0003]      FIG. 1  illustrates a communication system providing a PoC service. PoC clients  120  and  130  are cellular phones supporting PoC services. PoC client  120  comprises a PoC button  12   a , and PoC client  130  comprises a PoC button  13   a . PoC clients  120  and  130  communicate with a PoC server  110  via a PoC network  100 . The PoC network  100  can be a second generation GSM/GPRS network, or other network supporting a half duplex VOIP technology.  
         [0004]      FIGS. 2A and 2B  illustrate a flowchart of a conventional method of operating a PoC service. When a user of PoC client  120  wants to speak, a turn to speak must be obtained by first pressing PoC button  12   a (step S 210 ). PoC Client  120  sends a request to PoC server  110  to obtain the “floor” (step S 220 ). A PoC button Status is set to “pressed” (step S 230 ) while the PoC button continues to be pressed. PoC client  120  then waits for a floor grant message from PoC server  110  (step S 260 ). If the user decides while waiting that he no longer wish to speak, PoC button  12   a  is released (step S 240 ), and the PoC button status is set to “not pressed” (step S 250 ). When the floor is granted to PoC client  120  in response to the request, a grant message is sent to PoC client  120 . In step S 300 , the grant message is received by PoC client  120 . In step S 310 , it is determined whether the PoC button status is set as “pressed”. If the PoC button status is set as “not pressed”, a release request is sent from PoC client  120  to PoC server  110  to release the floor ( 350 ). If the PoC button status is set as “pressed”, a signal, such as a “beep” sound, is emitted to indicate that a talk session may be begin(step S 320 ). The voice transmitted from PoC client  120  is emitted from a built-in speaker in PoC client  130 . The user continues to press the PoC button  12   a  during the entire talk session (step S 330 ). When the PoC button is released in step S 340 , PoC client  120  sends a request to release the floor to PoC server (step S 350 ).  
         [0005]     In the conventional method, a user must continue pressing a PoC button during the entire talk session. During a long talk session, continuing to press the button may be inconvenient and cause physical discomfort.  
       SUMMARY  
       [0006]     A method for push to talk over cellular (PoC) operation is provided. The method is applied in a cellular phone with a PoC button associated. The method comprises: (A) detecting the PoC button has been pressed and released a first time, wherein the time length the PoC button has been pressed does not exceed a first time limit; (B) detecting the PoC button has been pressed and released a second time, wherein the time length the PoC button has been pressed the second time does not exceed the first time limit, wherein the time difference between the first and second times of releasing the PoC button does not exceed a second time limit; (C) assigning the PoC button a pressed button status when the PoC button has been pressed and then released the second time; (D) sending a floor grant request to establish an outward voice communication; (E) receiving a floor grant message; and (F) establishing and maintaining the outward voice communication wherein the PoC button is associated with the pressed button status.  
         [0007]     Another method for push to talk over cellular (POC) operation is provided. The method is applied in a cellular phone with a PoC button associated. The method comprises: (A) providing a PoC button associated with a cellular phone; (B) detecting the PoC button has been pressed a first time; (C) sending a floor grant request for establishing an outward voice communication after the PoC button has been pressed the first time; (D) detecting that the PoC button is kept on being pressed until a floor grant message is then received; (E) receiving a floor grant message; (F) detecting the PoC button has been released a first time after the floor grant message is received; (G) assigning the PoC button a pressed button status when the PoC button has been pressed and released the first time; and (H) establishing and maintaining the outward voice communication, wherein the PoC button is associated with the pressed button status.  
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0008]     The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:  
         [0009]      FIG. 1  illustrates a communication system providing a PoC service;  
         [0010]      FIGS. 2A and 2B  illustrate a flowchart of a conventional method of operating a PoC service;  
         [0011]      FIG. 3  illustrates a communication system providing a PoC service;  
         [0012]      FIGS. 4A and 4B  illustrate configurations for a Push-To-Talk operation setting;  
         [0013]      FIGS. 5A and 5B  illustrate a Push-To-Talk operation for a long talk session; and  
         [0014]      FIGS. 6A and 6B  illustrate another Push-To-Talk operation suitable for a long talk session.  
     
    
     DETAILED DESCRIPTION  
       [0015]     The invention will now be described with reference to  FIGS. 3 through 6 , which generally relate to operations of push to talk over cellular (PoC) service.  
         [0016]     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration of specific embodiments. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural, logical and electrical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. The leading digit(s) of reference numbers appearing in the figures corresponds to the Figure number, with the exception that the same reference number is used throughout to refer to an identical component which appears in multiple figures.  
         [0017]      FIG. 3  illustrates a communication system providing a PoC service. The push to talk service is implemented using a Push to Talk application server (PTT server)  310  in an IP Multimedia Subsystem (IMS) frame. The PTT server  310  handles call set-up signaling for Push to Talk calls, reservation of talk spurts for one speaker at a time and real-time routing of IP packets, and carrying talk spurts to the recipients. The PTT server  310  also provides an interface to an operator system  340 , and creates charge detail records, which can be used as a basis for billing. The Push to Talk scales to multimillion user networks with several networked Push to Talk application servers. A Push to Talk user database  311  stores data pertaining to provisioned users, their access rights, authentication information and preconfigured group membership. The users and talk groups can be arranged in the database in organization-specific closed user groups.  
         [0018]     PoC clients  320 ,  321 ,  323 , and  325  are cellular phones supporting PoC services. PoC clients  320 ,  321 ,  323 , and  325  comprise PoC buttons  320   a ,  321   a ,  323   a , and  325   a , respectively. PoC clients  320 ,  321 ,  323 , and  325  communicate with a PoC server  310  via a PoC network  300 . The PoC network  300  can be a second generation GSM/GPRS network, or other network supporting a half duplex VOIP technology.  
         [0019]     Users can form a talk group on an ‘ad hoc’ basis without having to contact their service providers, which facilitates spontaneous and flexible group communication. A user using PoC client  320  can select a desired phone number or talk group from a phone book stored in the PoC client  320 .  
         [0020]     For example, users A, B, and C use PoC clients  320 ,  321 , and  323 , respectively. Users A, B, and C are personnel in a manufacturing system, wherein user A is a supervisor, and users B and C are operators. When user A wants to know whether user B and C have been confronted by any problem, he sets up a PTT call to PoC clients  321  and  323 . First, user A has to obtain a grant message for a turn to speak (or a ‘floor’). At this time, the PTT call is intended for a short query. PoC button  320   a  is pressed, and a request for a floor grant message is sent to PoC server  310 . When receiving a floor grant message, an audio signal, such as a “beep”, is emitted to indicate that a talk session may begin, and user A starts to speak. Typically, about 2 seconds are required to obtain the floor grant message. User A continues pressing PoC button  320   a  until the intended short query is issued, for example, ‘Everything OK’. PoC button  320   a  is released after the short query is uttered. The voice transmitted from PoC client  320  is emitted from built-in speakers in PoC clients  321  and  323 . If user B or C wants to say something to user A or the entire group, the floor must first be obtained.  
         [0021]     For example, user B is confronted with a tool shut down situation, and wants to inform user A of the situation. If the desired PTT operation is enacted, user B must continue pressing PoC button  321   a  for the entire talk session. Details of the tool shut down situation, however, cannot be provided using just one or two words, and since user B is engaged in other activities, it may be inconvenient to describe the situation using the described PTT operation. Another PTT operation illustrated in  FIGS. 5A and 5B  is detailed as the following.  
         [0022]     The described PTT operations can be configured to meet special needs.  FIG. 4A  illustrates configuration of PTT settings.  FIG. 4A  illustrates a default PTT operation setting configuration. In setting display  40 , check boxes  41 ,  43 , and  45  are presented. When none of the three check boxes is selected, a default PTT operation (as described in  FIG. 2A &amp; 2B ) is configured. When check box  41  is selected, a “double-click” PTT operation is enabled. When check box  43  is selected, a “long talk without pressing PoC button” PTT operation is enabled. When check box  45  is selected, a silence threshold must be set, and the silence detection mechanism is enabled.  
         [0023]     Using  FIG. 4B  as an example, when none of check boxes  41 ,  43 , and  45  is selected, a default PTT operation is performed (as shown in condition  400 ). When check box  41  is selected, a “double-click” PTT operation is enabled (as shown in condition  410 ). When check box  43  is selected, a “long talk without pressing PoC button” PTT operation is enabled (as shown in condition  430 ). When check box  45  is selected, a silence threshold must be set, and the silence detection mechanism is enabled.  
         [0024]     When check box  41  is selected, user needs not to press PoC button during a talk session by double-clicking the PoC button to initiate the “double-click” PTT operation. Additionally, when check box  41  is selected, check box  45  can be selected optionally. The silence detection is preformed according to the silence period determined by the user.  
         [0025]     When check box  43  is selected, user needs to press PoC button until a floor grant is received, and then the PoC button is released during a talk session. Additionally, when check box  43  is selected, check box  45  can be selected optionally. The silence detection is preformed according to the silence period determined by the user.  
         [0026]     It should be noted that the default PTT operation, the “double-click” PTT operation, and the “long talk without pressing PoC button” PTT operation are not exclusive. That is, when both check boxed  41  and  43  are selected, the cellular phone can be operated in one of the tree operations according to the pressing status of the PoC button. For example, when the user presses the PoC button and keeps on pressing the PoC button even when the floor grant message is received and during the talk session, it can be known that the user operates the cellular phone in the default PTT operation.  
         [0027]     When the user double-clicks the PoC button, it can be known that the user operates the cellular phone in the “double-click” PTT operation. And when the user presses the PoC button and then releases the PoC button when the floor grant message is received, it can be known that the user operates the cellular phone in the the “long talk without pressing POC button” PTT operation.  
         [0028]      FIGS. 5A and 5B  illustrate a PTT operation for a long talk session (i.e. the “double-click” PTT operation). Referring to  FIG. 5A , when user B wants to speak to user A, a turn to speak must be obtained by pressing and releasing PoC button twice, wherein the time length the PoC button has been pressed does not exceed a first time limit (step S 410 ). Here, pressing and releasing PoC button twice and the time length the PoC button has been pressed is within a predetermined short period of time can also be referred to as “double-clicking” PoC button. PoC Client  321  sends a request to PoC server  310  to obtain the “floor” (step S 420 ). A PoC button status is set to “pressed” when the PoC button is pressed and released twice and the time length the PoC button has been pressed is within a predetermined short period of time, i.e. when the PoC button is double-clicked (step S 430 ). PoC client  321  then waits for a floor grant message from PoC server  310  (step S 460 ). If user B does not want to speak anymore during the waiting, PoC button  321   a  is pressed and released (clicked) (step S 440 ), and the PoC button status is set to “not pressed” (step S 450 ).  
         [0029]     When the floor is granted to the user B in response to the request, a grant message is sent to PoC client  321 . Referring to  FIG. 5B , in step S 500 , the floor grant message is received by PoC client  321 . In step S 510 , it is determined whether the PoC button status is set to “pressed”. If the PoC button status is set as “not pressed”, a release request is sent from PoC client  321  to PoC server  310  to release the floor ( 550 ). If the PoC button status is set as “pressed”, an audio signal, such as a “beep”, is emitted indicating that a talk session may begin (step S 520 ). User B reports the tool shut down situation to user A without pressing the PoC button  321   a , that is, the PoC button  321   a  is released during the entire talk session (step S 530 ). When user B finishes his report and wants to close the talk session, he clicks PoC button  321   a  in step S 540 . PoC client  321  then sends a request to release the floor to PoC server  310  (step S 550 ). If user B is engaged and cannot clicks PoC button  321   a  when he finishes the report, a silence detection mechanism can be used for closing the talk session automatically. According to the silence detection mechanism, if user B is silent for a preset period of time, the PoC button status is reset to ‘not pressed’, and a request to release the floor is automatically sent to PoC server  310 . The preset period of time can be, for example, 5 or 10 seconds.  
         [0030]      FIGS. 6A and 6B  illustrate another PTT operation suitable for a long talk session (i.e. the “long talk without pressing PoC button” PTT operation). After user A understands what user B has said, he may want to instruct both users B and C to handle the tool shut down situation. User A selects a talk group comprising PoC clients  321  and  323 , and obtains a floor grant by pressing PoC button  320   a  at first (step S 610 ). PoC Client  320  sends a request to PoC server  310  to obtain the “floor” (step S 620 ). A PoC button status is set to “pressed” when PoC button  320   a  continues to be pressed (step S 630 ). PoC client  320  then waits for a floor grant message from PoC server  310  (step S 660 ) If user A does not want to speak anymore during the waiting, PoC button  320   a  is released (step S 640 ) and the PoC button status is set to “not pressed” (step S 650 ).  
         [0031]     When the floor is granted to the user in response to the request, a floor grant message is sent to PoC client  320 . Referring to  FIG. 6B , in step S 700 , the floor grant message is received by PoC client  320 . In step S 710 , it is determined whether the PoC button status is set to “pressed”. If the PoC button status is set as “not pressed”, a release request is sent from PoC client  320  to PoC server  310  to release the floor (step S 750 ). If the PoC button status is set as “pressed”, an audio signal, such as a “beep”, is emitted to indicate that a talk session may begin (step S 720 ). User A gives instructions for handling the tool shut down situation to users B and C, while PoC button  321   a  is released during the entire talk session (step S 730 ). When user A finishes his instruction and wants to close the talk session, he clicks PoC button  320   a  in step S 740 . PoC client  320  then sends a request to release the floor to PoC server  310  (step S 750 ). If user A is engaged and cannot click PoC button  320   a  when he finishes speaking, a silence detection mechanism can be used for closing the talk session automatically (step S 760 ). According to the silence detection mechanism, if user A is silent during a preset period of time, the PoC button status is reset to ‘not pressed’, and a request to release the floor is automatically sent to PoC server  310 . The preset period of time can be, for example, 5 or 10 seconds.  
         [0032]     While the invention has been described by way of example and in terms of several embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.