Patent Publication Number: US-2011065481-A1

Title: Advanced features on a real-time exchange system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional under 35 U.S.C. Section 121 of co-pending and commonly-assigned U.S. Utility patent application Ser. No. 11/740,805, filed on Apr. 26, 2007, by Krishnakant M. Patel, Giridhar K. Boray, Ravi Ayyasamy, and Gorachand Kundu, entitled “ADVANCED FEATURES ON A REAL-TIME EXCHANGE SYSTEM,” attorneys&#39; docket number 154.26-US-U1, which application claims the benefit under 35 U.S.C. Section 119(e) of co-pending and commonly-assigned U.S. Provisional Patent Application Ser. No. 60/795,090, filed on Apr. 26, 2006, by Krishnakant M. Patel, Giridhar K. Boray, Ravi Ayyasamy, and Gorachand Kundu, entitled “ADVANCED FEATURES ON A REAL-TIME EXCHANGE SYSTEM,” attorneys&#39; docket number 154.26-US-P1, both of which applications are incorporated by reference herein. 
     This application is related to the following co-pending and commonly-assigned patent applications: 
     U.S. Utility application Ser. No. 10/515,556, filed Nov. 23, 2004, by Gorachand Kundu, Ravi Ayyasamy and Krishnakant Patel, entitled “DISPATCH SERVICE ARCHITECTURE FRAMEWORK,” attorney docket number G&amp;C 154.4-US-WO, which application claims the benefit under 35 U.S.C. Section 365 of P.C.T. International Patent Application Serial Number PCT/US03/16386 (154.4-WO-U1), which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. Nos. 60/382,981 (154.3-US-P1), 60/383,179 (154.4-US-P1) and 60/407,168 (154.5-US-P1); 
     U.S. Utility application Ser. No. 10/564,903, filed Jan. 17, 2006, by F. Craig Farrill, Bruce D. Lawler and Krishnakant M. Patel, entitled “PREMIUM VOICE SERVICES FOR WIRELESS COMMUNICATIONS SYSTEMS,” attorney docket number G&amp;C 154.7-US-WO, which application claims the benefit under 35 U.S.C. Section 365 of P.C.T. International Patent Application Ser. No. PCT/USO4/23038 (154.7-WO-U1), which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. Nos. 60/488,638 (154.7-US-P1), 60/492,650 (154.8-US-P1) and 60/576,094 (154.14-US-P1) and which application is a continuation-in-part and claims the benefit under 35 U.S.C. Sections 119, 120 and/or 365 of P.C.T. International Patent Application Serial Number PCT/US03/16386 (154.4-WO-U1); 
     U.S. patent application Ser. No. 11/126,587, filed May 11, 2005, by Ravi Ayyasamy and Krishnakant M. Patel, entitled “ARCHITECTURE, CLIENT SPECIFICATION AND APPLICATION PROGRAMMING INTERFACE (API) FOR SUPPORTING ADVANCED VOICE SERVICES (AVS) INCLUDING PUSH TO TALK ON WIRELESS MS 120 AND NETWORKS,” attorney docket number 154.9-US-U1, now U.S. Pat. No. 7,738,892, issued Jun. 15, 2010, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. Nos. 60/569,953 (154.9-US-P1) and 60/579,309 (154.15-US-P1), and which application is a continuation-in-part and claims the benefit under 35 U.S.C. Sections 119, 120 and/or 365 of U.S. Utility patent application Ser. No. 10/515,556 (154.4-US-WO) and P.C.T. International Patent Application Ser. No. PCT/USO4/23038 (154.7-WO-U1); 
     U.S. Utility patent application Ser. No. 11/129,268, filed May 13, 2005, by Krishnakant M. Patel, Gorachand Kundu, Ravi Ayyasamy and Basem Ardah, entitled 
     “ROAMING GATEWAY FOR SUPPORT OF ADVANCED VOICE SERVICES WHILE ROAMING IN WIRELESS COMMUNICATIONS SYSTEMS,” attorney docket number 154.10-US-U1, now U.S. Pat. No. 7,403,775, issued Jul. 22, 2008, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/571,075 (154.10-US-P1), and which application is a continuation-in-part and claims the benefit under 35 U.S.C. Sections 119, 120 and/or 365 of U.S. Utility patent application Ser. No. 10/515,556 (154.4-US-WO) and P.C.T. International Patent Application Ser. No. PCT/USO4/23038 (154.7-WO-U1); 
     U.S. Utility patent application Ser. No. 11/134,883, filed May 23, 2005, by Krishnakant Patel, Vyankatesh V. Shanbhag, Ravi Ayyasamy, Stephen R. Horton and Shan-Jen Chiou, entitled “ADVANCED VOICE SERVICES ARCHITECTURE FRAMEWORK,” attorney docket number 154.11-US-U1, now U.S. Patent No. 7,764,950, issued Jul. 27, 2010, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. Nos. 60/573,059 (154.11-US-P1) and 60/576,092 (154.12-US-P1), and which application is a continuation-in-part and claims the benefit under 35 U.S.C. Sections 119, 120 and/or 365 of U.S. Utility patent application Ser. No. 10/515,556 (154.4-US-W0), P.C.T. International Patent Application Ser. No. PCT/USO4/23038 (154.7-WO-U1), U.S. Utility patent application Ser. No. 11/126,587 (154.9-US-U1), and U.S. Utility patent application Ser. No. 11/129,268 (154.10-US-U1); 
     U.S. Utility patent application Ser. No. 11/136,233, filed May 24, 2005, by Krishnakant M. Patel, Vyankatesh Vasant Shanbhag, and Anand Narayanan, entitled “SUBSCRIBER INFORMATION MODULE (SIM) ENABLING ADVANCED VOICE SERVICES (AVS) INCLUDING PUSH TO TALK ON WIRELESS MS 120 AND NETWORKS,” attorney docket number 154.13-US-U1, now U.S. Pat. No. 7,738,896, issued Jun. 15, 2010, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/573,780 (154.13-US-P1), and which application is a continuation-in-part and claims the benefit under 35 U.S.C. Sections 119, 120 and/or 365 of U.S. Utility patent application Ser. No. 10/515,556 (154.4-US-WO), P.C.T. International Patent Application Serial Number PCT/USO4/23038 (154.7-WO-U1), U.S. Utility patent application Ser. No. 11/126,587 (154.9-US-U1), and U.S. Utility patent application Ser. No. 11/134,883 (154.11-US-U1); 
     U.S. Utility patent application Ser. No. 11/158,527, filed Jun. 22, 2005, by F. Craig Farrill, entitled “PRESS-TO-CONNECT FOR WIRELESS COMMUNICATIONS SYSTEMS,” attorney docket number 154.16-US-U1, now U.S. Pat. No. 7,529,557, issued May 5, 2009, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/581,954 (154.16-US-P1), and which application is a continuation-in-part and claims the benefit under 35 U.S.C. Sections 119, 120 and/or 365 of U.S. Utility patent application Ser. No. 10/515,556 (154.4-US-WO) and P.C.T. International Patent Application Serial Number PCT/USO4/23038 (154.7-WO-U1); U.S. Utility patent application Ser. No. 11/183,516, filed Jul. 18, 2005, by Deepankar Biswaas, entitled “VIRTUAL PUSH TO TALK (PTT) AND PUSH TO SHARE (PTS) FOR WIRELESS COMMUNICATIONS SYSTEMS,” attorney docket number 154.17-US-U1, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/588,464 (154.17-US-P1); U.S. Utility patent application Ser. No. 11/356,775, filed Feb. 17, 2006, by Krishnakant M. Patel, Bruce D. Lawler, Giridhar K. Boray, and Brahmananda R. Vempati, entitled “ENHANCED FEATURES IN AN ADVANCED VOICE SERVICES (AVS) FRAMEWORK FOR WIRELESS COMMUNICATIONS SYSTEMS,” attorney docket number 154.18-US-U1, now U.S. Pat. No. 7,813,722, issued Oct. 12, 2010, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/654,271(154.18-US-P1); 
     P.C.T. International Patent Application Serial Number PCT/US2006/011628, filed Mar. 30, 2006, by Krishnakant M. Patel, Gorachand Kundu, Sameer Dharangaonkar, Giridhar K. Boray, and Deepankar Biswas, entitled “TECHNIQUE FOR IMPLEMENTING ADVANCED VOICE SERVICES USING AN UNSTRUCTURED SUPPLEMENTARY SERVICE DATA (USSD) INTERFACE,” attorney docket number 154.19-WO-U1, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/666,424 (154.19-US-P1); 
     U.S. Utility patent application Ser. No. 11/462,332, filed Aug. 3, 2006, by Deepankar Biswas, Krishnakant M. Patel, Giridhar K. Boray, and Gorachand Kundu, entitled “ARCHITECTURE AND IMPLEMENTATION OF CLOSED USER GROUP AND LIMITING MOBILITY IN WIRELESS NETWORKS,” attorney docket number 154.20-US-U1, now U.S. Pat. No. 7,689,238, issued Mar. 30, 2010, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/705,115 (154.20-US-P1); 
     U.S. Utility patent application Ser. No. 11/463,186 , filed Aug. 8, 2006, by Ravi Ayyasamy and Krishnakant M. Patel, entitled “ADVANCED VOICE SERVICES CLIENT FOR BREW PLATFORM,” attorney docket number 154.21-US-U1, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/706,265 (154.21-US-P1); 
     U.S. Utility patent application Ser. No. 11/567,098, filed Dec. 5, 2006, by Ravi Ayyasamy, Bruce D. Lawler, Krishnakant M. Patel, Vyankatesh V. Shanbhag, Brahmananda R. Vempati, and Ravi Shankar Kumar, entitled “INSTANT MESSAGING INTERWORKING IN AN ADVANCED VOICE SERVICES (AVS) FRAMEWORK FOR WIRELESS COMMUNICATIONS SYSTEMS,” attorney docket number 154.23-US-U1, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/795,090 (154.23-US-P1); 
     all of which applications are incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates in general to wireless communications systems, and more specifically, to enhanced features for advanced voice services wireless communications systems. 
     2. Description of Related Art 
     Advanced voice services (AVS), such as two-way half-duplex voice calls within a group, also known as Push-to-Talk (PTT) or Press-to-Talk (P2T), as well as other AVS functions, such as Push-to-Conference (P2C) or Instant Conferencing, Upgrade to Conference, Push-to-Message (P2M), etc., are described in the co-pending and commonly-assigned patent applications cross-referenced above and incorporated by reference herein. These AVS functions have enormous revenue earnings potential for wireless communications systems, such as cellular networks and personal communications systems (PCS) networks. 
     Currently, there are three major approaches employed in providing advanced voice services in wireless communications systems. One approach requires the installation of a dedicated private network, parallel to the wireless communications system, to support the group-based voice services. NEXTEL uses such a system, based on a solution developed by MOTOROLA known as IDEN. However, a dedicated private network is costly to install and maintain and is employed by a few public wireless carriers. Also, the IDEN system is non-standard, and hence cannot be used in standard wireless communications networks, such as those based on GSM (Global System for Mobile Communications) and CDMA (Code Division Multiple Access). 
     Another approach is based on Voice over IP (VoIP) technologies. While this approach promises compliance with newer and emerging standards, such as GPRS (General Packet Radio Service), UMTS (Universal Mobile Telecommunications System), etc., it does not provide a solution for carriers employing wireless communications systems based on existing standards, such as GSM, CDMA, etc. However, even for the newer standards, solutions based on VoIP have serious drawbacks, including slower call setup, significant overhead, increased susceptibility to packet losses, low bit rate voice coders, and significant modifications to the mobile handset. There is a need, instead, for solutions that require only minimal upgrades to the handset. 
     Still another approach is that defined in the co-pending and commonly-assigned patent applications cross-referenced above and incorporated by reference herein. In this approach, advanced voice services are provided by a dispatch gateway (DG) or real-time exchange (RTX) that interfaces to the wireless communications system to provide the advanced voice services therein, wherein both the dispatch gateway and mobiles that use the advanced voice services communicate with each other using call setup and in-band signaling within the wireless communications system. 
     Notwithstanding these innovations, there is a need in the art for other advanced voice services that comply with existing and emerging wireless standards and provide superior user experiences. The present invention aims to satisfy this need by providing enhanced features in advanced voice services for wireless communications systems. 
     SUMMARY OF THE INVENTION 
     To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses enhanced features for advanced voice services for wireless communications systems. A real-time exchange (RTX) interfaces to the wireless communications system to provide these enhanced features for the advanced voice services, which include Voice Activated Floor Management, Voice Short Message Services (SMS) and Address Book Backup. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring now to the drawings in which like reference numbers represent corresponding parts throughout: 
         FIG. 1  is a block diagram that illustrates an exemplary embodiment of the dispatch services architecture framework according to a preferred embodiment of the present invention; 
         FIG. 2  is a block diagram that illustrates the architecture of the real-time exchange according to the preferred embodiment of the present invention; 
         FIG. 3  illustrates the architecture used by the present invention in leveraging the underlying voice recognition systems of a wireless communications network;  FIG. 4  is a state diagram that illustrates the operation of a Push-to-Talk (PTT) call according to a preferred embodiment of the present invention; and 
         FIG. 5  illustrates a system architecture for the Voice Short Message System (SMS) service according to the preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description of the preferred embodiment, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration the specific embodiment in which the invention may be practiced. It is to be understood that other embodiments may be utilized as structural changes may be made without departing from the scope of the present invention. 
     Overview 
     The present invention describes a wireless communications network that is used for making calls to and from mobile units, wherein the calls are initiated by call setup and in-band signaling within the wireless communications network and voice frames for the calls are switched between the mobile units across bearer paths in the wireless communications network. A real-time exchange interfaces to the wireless communications network to provide an advanced features for use with advanced voice service (AVS) for the wireless communications network. Specifically, the advanced features for AVS comprises Voice Activated Floor Management, Voice Short Message Services (SMS) and Address Book Backup. 
     Network Architecture 
       FIG. 1  is a block diagram that illustrates an exemplary embodiment of a wireless communications network  100  according to a preferred embodiment of the present invention for making calls to and from mobile units. 
     Within the network  100 , an RTX (Real-Time Exchange)  102 , previously known as a Dispatch Gateway (DG), communicates with a MSC (Mobile Switching Center)  104  and PSTN (Public Switched Telephone Network)  106  using SS7-ISUP/WIN/CAMEL (Signaling System 7—Integrated Services Digital Network User Part/Wireless Intelligent Network/Customized Applications for Mobile Enhanced Logic) messages at a signaling plane  108 . 
     A bearer path  110  implements a TDM (Time Division Multiplexing) interface carrying PCM (Pulse Code Modulation) or TFO (Tandem Free Operation) voice frames. Support for TFO in this path  110  is negotiated between a BSC (Base Station Controller)  112  and the RTX  102  for each originating and terminating leg of an AVS call. The use of TFO ensures high voice quality (as voice vocoder conversion is avoided) between mobile-to-mobile calls. 
     When a subscriber originates an AVS call, the MSC  104  routes the call to the RTX  102 . The MSC  104  also requests the BSC  112  via  116  to establish a radio traffic path  118  with a mobile station (MS)  120  (also known as a handset or mobile unit) via the BTS (Base 
     Transceiver Station)  122  (as it does for a normal cellular call). At this time, the BSC  112  tries to negotiate TFO (if it is supported) on a TDM link with the far end (in this case, the RTX  102 ). 
     At the same time (after the MSC  104  terminates the group call request to the RTX  102 ), the RTX  102  identifies the terminating group users and their MS-ISDN (Mobile Station—Integrated Services Digital Network) numbers. It sends an ISUP call origination request for each terminating MS  120 . It may send requests directly to the MSC  104 , PSTN  106  or IP network  124  via a PDSN (Public Data Switched Network)  126 , Router  128 , and/or Internet/Intranet  130 , depending on the routing table configuration for terminating MS-ISDN numbers. 
     Once the bearer path  110  is established, the RTX  102  begins a negotiation with the far end (in this case, the terminating BSC  112 ) for each terminating leg to an MS  120 . 
     Once bearer paths  110  are established for originating and terminating legs for an AVS call, the RTX  102  switches (or duplicates) voice frames from the originating MS  120  to all terminating MS&#39;s  120 . 
     The RTX  102  may use an IP network  124  or the Internet/Intranet  130  for two different purposes. The IP network  124  or the Internet/Intranet  130  can be used in a toll bypass mode where two RTXs  102  can exchange voice traffic bypassing the PSTN  106 . However, each RTX  102  is responsible for terminating traffic to its closest MSC  104 . In this case, the IP network  124  or the Internet/Intranet  130  is used as a backbone transport of voice traffic between two RTXs  102 . 
     The IP network  124  or the Internet/Intranet  130  can also be used for a registration and presence application. Since the MSC  104  will not direct a registration request from an MS  120  to the RTX  102  (because it would require changes in the MSC  104 ), the latter does not have any information of the registered MS  120 . To circumvent this issue, a registration and presence application runs over an IP stack in the MS  120 . After the MS  120  registers for a data interface (i.e., obtaining an IP address) with the PDSN  126  (or Serving GSM Service Nodes (SGSN) in the case of GSM networks), the registration and presence application in the MS  120  registers with the RTX  102  using its IP address. The RTX  102  also uses this IP interface to update the presence information of other group members to an MS  120 . 
     An alternative embodiment would use the SMS (Short Message Service) transport to carry presence messages over a data channel. The RTX  102  interacts with the MS  120  using predefined presence application related messages that are transported as SMS messages. The same messages can be transported via the PDSN  126  interface, if group users have data service. 
     Real Time Exchange 
       FIG. 2  illustrates a proposed architecture for the RTX  102  according to the preferred embodiment of the present invention. 
     The architecture includes a Call Processing system  200 , Presence Server  202 , Real-Time Event Processing system  204 , one or more Media Managers  206 , and an SMPP (Short Message Peer-to-Peer) Transport  208 , as well as modules for various SS7 protocols, such as MTP- 1  (Message Transfer Part Level  1 )  210 , MTP- 2  (Message Transfer Part Level  2 )  212 , MTP- 3  (Message Transfer Part Level  3 )  214 , ISUP (Integrated Services Digital Network User Part)  216 , SCCP (Signaling Connection Control Part)  218 , and TCAP (Transactions Capabilities Application Part)  220  protocols. 
     The Call Processing system  200 , Presence Server  202 , Media Managers  204 , SMPP Transport  206 , and other modules communicate across an IP network  222 . The Real-Time Event Processing system  204  communicates directly with the Call Processing system  200 , Presence Server  202 , and the modules for various SS7 protocols. The modules for various SS7 protocols communicate with other entities via a SS7 Signaling Link  224 . The SMPP Transport  206  communicates with a SMSC (Short Message Service Center) gateway using the SMPP protocol  226 . The Media Managers  204  communicate among themselves using the H.110 protocol  228  (or some other protocol, such TCP/IP). 
     The operation of these various components are described in more detail below, as well as in the co-pending and commonly-assigned patent applications cross-referenced above and incorporated by reference herein. 
     The originating MS  120  signals the RTX  102  via the wireless network  100 , e.g., by transmitting one or more configured DTMF (Dual Tone Multi Frequency) digits or other signals to the RTX  102 . The Media Manager systems  206  receive the DTMF digits or other signals, and pass the DTMF digits or other signals to the Call Processing system  200 . The Call Processing (CP) system  200  determines whether the originating MS  120  has subscribed to the AVS feature before originating the AVS session. Upon confirmation, the Call Processing system  200  initiates a new AVS session. The Call Processing system  200  interacts with the Presence Server  202  and Real-Time Event Processing system  204  to cause the wireless network  100  to perform session setup for the AVS session, and thereafter to manage the AVS session. 
     During the AVS session, for example, the Call Processing system  200  interacts with the Media Manager systems  206  to maintain the H.110 channels  227  and assign any additional H.110 channels  228  required for the AVS session, which may span across multiple Media Manager systems  206 . Moreover, the Media Manager systems  206  of the RTX  102  may be used, for example, to mix audio streams between the originating MS  120  and the terminating MS  120 , and then deliver these mixed audio streams to the originating MS  120  and the terminating MS  120 . The H.110 channels  228  are used for passing mixed and unmixed audio streams voice between the Media Manager systems  200  as required. 
     Voice Portal Integration 
     In one embodiment, the enhanced features comprise voice recognition services for enhancing the calls to and from the MS  120 . These features are provided using a voice portal. Voice portals provide telephone users with a natural language interface to access and retrieve network  100  services. Typically, voice portals are based on speaker-independent speech recognition technologies. Hence, this solution also applies equally well to AVS-enabled handsets and non-AVS-enabled handsets, including landline phones. 
     For example, voice portals have been extensively used for 1-800 directory enquiry, flight information, etc., and have matured over the years with improved speech recognition accuracy. In addition, the advent of standard voice scripting language, such as VoiceXML, has fueled growth of voice portal services just as HTML did for web services. 
     Additional information concerning voice portals can be found in U.S. Utility patent application Ser. No. 11/356,775, filed Feb. 17, 2006, by Krishnakant M. Patel, Bruce D. Lawler, Giridhar K. Boray, and Brahmananda R. Vempati, entitled “ENHANCED FEATURES IN AN ADVANCED VOICE SERVICES (AVS) FRAMEWORK FOR WIRELESS COMMUNICATIONS SYSTEMS,” attorney docket number 154.18-US-U1, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Serial Number 60/654,271(154.18-US-P1), which applications are incorporated by reference herein. 
       FIG. 3  illustrates the architecture used by the present invention in leveraging the underlying voice recognition systems of a wireless communications network  100 . In this embodiment, the RTX  102  interfaces to one or more Voice Portals (VPs)  300 , as well as an Integrated Local and Transit (ILT) switch  302 . The ILT  302  also interfaces to the VP  400  via a Media Gateway (MG)  404 . In addition, the RTX  102  interfaces to the MSC  104  through the ILT  402  (or interfaces directly to the MSC  104  as shown in  FIG. 1 ) to control call signaling, as well as voice frame buffering and duplication. 
     The integration of the RTX  102  with a standard VP  300  opens up unlimited possibilities to expand the reach of AVS. Moreover, the integration of the RTX  102  with the VP  300  eliminates the need for a client in the MS  120 . 
     Consider the example where the voice recognition services are used to invoke PTT services within a group of MS  120  identified in the RTX  102 . The typical scenario comprises the following:
         the user dials a pre-determined code on the MS  120  to access the VP  300 ,   the MS  120  receives a confirmation tone from the VP  300 ,   the user inputs a voice command on the MS  120  (for example, by saying “call friends”) to invoke a PTT call with a group identified as “friends” in the RTX  102 ,   the VP  300  performs speech recognition and sends the decoded message to the RTX  102 , and   the RTX  102  places the PTT call to the chosen group.       

     Voice Activated Floor Management 
     In the present invention, the RTX  102  interfaces to the wireless communications network  100  to provide a half-duplex Push-to-Talk (PTT) session between an initiator and two or more other participants, wherein both the TX  102  and MS  120  participating in the PTT session communicate with each other using call setup and in-band signaling within the wireless communications network  100 . The other participants comprise one or more contacts, one or more groups of contacts, or a subset of a group of contacts. 
     In other embodiments, for example as described in the cross-referenced applications set forth above, PTT is a command-and-control service that requires every participant in a multi-party call to have purpose-built handsets with a designated PTT button and a speaker. The PTT button aids in acquisition and release of floor in half-duplex, multi-party conversations. However, the requirement of having every user with special purpose handsets severely restricts the reach of this service, and thus there is a need for a solution that would apply to all terminal devices. 
     The present invention provides a solution for PTT floor management based on voice activity detection (VAD) in the RTX  102 , with or without the voice recognition services of the VP  300 . Specifically, the voice activity detection aids in acquisition and release of the floor of the PTT session, wherein the voice activity detection is based on detecting a level of voice activity from the initiator or other participants. 
     Floor management of the PTT session performed using voice activity detection obviates the need for purpose-built PTT handsets. In addition, the use of voice activity detection to perform floor management is also a natural way of controlling the floor. 
     There are a number of user benefits to this approach. For example, there is no need to purchase a purpose-built PTT handset. Moreover, there is no need to press and hold a PTT button while speaking. 
     There are also a number of network operator benefits to this approach. For example, the present invention expands the reach of RTX  102  enabled AVS by allowing users to experience PTT without the need of purpose-built PTT handsets. Moreover, the present invention allows PTT users from multiple networks to be part of a group call. 
       FIG. 4  is a state diagram that illustrates the operation of a PTT call according to a preferred embodiment of the present invention. 
     State  400  represents an MS  120  in a NULL state, i.e., the start of the logic. A transition out of this state is triggered by a user making a request to originate a PTT call, or by a request being made to terminate a PTT call at the MS  120 . A request to originate a PTT call is normally made by pressing a PTT button, but may be initiated in this embodiment by dialing some sequence of one or more numbers on the MS  120  that are interpreted by the RTX  102 , by pressing one or more other keys on the MS  120  that are interpreted by the RTX  102 , by speaking one or more commands that are interpreted by the VP  400 , or by some other means. 
     State  402  represents an MS  120  in an active group call state. In this state, the user receives a chirp tone that indicates that the user may start talking The user responds by talking on the MS  120 . The MS  120  uses the reverse traffic channel to send voice frames to the RTX  102 , and the RTX  102  switches voice frames only in one direction, i.e., from talker to one or more listeners, which ensures the half-duplex operation required for a PTT call. 
     State  404  represents the group “floor” being available to all members of the group. When the talking user signals that the floor is released, the floor is available to all group members. The signal to release the floor is normally made by releasing the PTT button, but may be performed in this embodiment by voice activity detection, e.g., by not speaking for some time period (which is interpreted by RTX  102  as a release command). All members of the group receive a “free floor” tone on their MS  120 . A user who requests the floor first (in the “free-floor” state), for example, is assigned the floor, wherein the network  100  sends a chirp tone to the successful user. The signal to request the floor is normally made by pressing the PTT button, but may be performed in this embodiment by voice activity detection, e.g., by speaking for some time period (which is interpreted by RTX  102  as a request command). 
     State  406  represents an MS  120  being in an active group call state. In this state, the user is listening to the group call. If a non-talking user requests the floor in the active group call state, the user does not receive any response from the network  100  and remains in the same functional state. As noted above, the signal to request the floor is normally made by pressing the PTT button, but may be performed in this embodiment by voice activity detection, e.g., by speaking for some time period (which is interpreted by RTX  102  as a request command). 
     State  408  represents a user receiving an “unsuccessful bidding” tone on his MS  120 , after the user has requested the floor, but was not granted the floor, of the group call. The user subsequently listens to the voice message of the talking user. 
     Non-talking users (including the talking user who must release the floor to make it available for others) can request the network  100  to end their respective call legs explicitly. 
     State  410  represents a terminating leg being released from the call after the user ends the call. 
     State  412  also represents a terminating leg being released from the call after the user ends the call. 
     State  414  represents all terminating legs being released from the call when no user makes a request for the within a specified time period, or after all users have ended their respective call legs. 
     Voice Short Message Service (SMS) 
     In the present invention, the RTX  102  interfaces to the wireless communications network  100  to provide a Voice Short Message Service (SMS) message that comprises a short voice message, wherein a user sends the Voice SMS message to at least one contact, in a manner similar to sending a short text message, using their mobile unit. The Voice Short Message Service (SMS) is a value-added feature that allows a user to send short voice messages to one or more contacts, in a manner similar to the sending of short text messages, using the click of a button, on the MS  120 . 
     In one embodiment, the user initiates a call to a Voice SMS number associated with the contact, the RTX  102  provides an indication to the user to start speaking the Voice SMS message, the RTX  102  provides for the storage of the Voice SMS message, and then the user then ends the call after completing the Voice SMS message. Thereafter, the contact receives the text SMS message on their MS  120  indicating that the Voice SMS message has been sent, the contact dials a callback number for the Voice SMS, and then the contact listens to the Voice SMS message. Finally, the RTX  102  deletes the Voice SMS message after a configured retention period or in response to a user command. 
     The benefits to the user of this invention are that it provides a fast and easy messaging mechanism. Moreover, it does away with the typing of messages. In addition, there is inherent multiple language support 
     The benefits to the network operator of this invention is that it provides a new feature for a large group of users that my not be used to typing SMS messages. Moreover, the attractiveness of voice as a messaging medium enhances network usage. In addition, it grows average revenue per user (ARPU) for the operator. Finally, the invention only requires the existing network infrastructure to deploy the service. 
     Note that, because the information being shared is communicated by SMS, it may comprise any number of different types of data other than just voice. For example, Voice SMS messages may comprise multimedia SMS messages (e.g., audio, video, images, data, etc.). 
     In one embodiment, the Voice SMS feature may use the functionality of the Press-to-Message (P 2 M) service described in co-pending and commonly-assigned P.C.T. International Patent Application Number PCT/USO4/23038, filed Jul. 16, 2004, by F. Craig Farrill, Bruce D. Lawler and Krishnakant M. Patel, entitled “PREMIUM VOICE SERVICES FOR WIRELESS COMMUNICATIONS SYSTEMS,” attorney docket number 154.7-WO-U1, which application is set forth above, and incorporated by reference herein. The P 2 M service uses the MMS (Multi Media Services) protocol as the transport medium. The P 2 M service delivers multimedia messages (e.g., audio, video, images, data, etc.), known hereafter as P 2 M messages from an originator to one or more recipients. 
       FIG. 5  illustrates a system architecture for the Voice SMS feature according to the preferred embodiment of the present invention. The system architecture includes one or more RTXs  102  coupled to a P 2 M server  500 , which is (optionally) coupled to a Voice Mail Server  502 , wherein the RTX  102  and the P 2 M Server  500  work together to deliver Voice SMS messages in a non-real time manner from an originator to one or more recipients, without establishing voice paths between the originator and recipients. Recipients may comprise one or more contacts, one or more groups of contacts, or a subset of a group of contacts. 
     The P 2 M Server  500  provides a message storage facility for Voice SMS messages, or may interface to the Voice Mail Server  502  to provide a message storage facility for the Voice SMS messages. The user can store Voice SMS messages, retrieve Voice SMS messages, reply to Voice SMS messages, or forward Voice SMS messages to other subscribers. The P 2 M Server  500  supports the sending of Voice SMS messages to one or more contacts, one or more groups of contacts, or a subset of a group of contacts. 
     Address Book Backup 
     In the present invention, the RTX  102  interfaces to the wireless communications network  100  to perform an “over-the-air” backup of an address book stored on an MS  120  via the wireless communications network  100  for subsequent storage in a network server separate from the MS  120 , wherein the network server may be the RTX  102  it self, or the P 2 M Server  500 , or another storage system. 
     In one embodiment, a client application on the MS  120  detects a change to the address book stored on the MS  120  unit and automatically uploads the address book to the RTX  102 . In another embodiment, a client application on the MS  120  performs a periodic backup of the address book stored on the MS  120  by uploading the address book to the RTX  102 . In both embodiments, the address book is stored by the RTX  102  on the network server, which may be available to the user via Internet access, such that any changes made to the address book stored on the network server can be downloaded by the RTX  102  to the MS  120  via the wireless communications network  100 . 
     Note that such functionality may integrated with the techniques described in U.S. Utility patent application Ser. No. 11/183,516, filed Jul. 18, 2005, by Deepankar Biswaas, entitled “VIRTUAL PUSH TO TALK (PTT) AND PUSH TO SHARE (PTS) FOR WIRELESS COMMUNICATIONS SYSTEMS,” attorney docket number 154.17-US-U1, which application claims the benefit under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60/588,464 (154.17-US-P1), which applications are incorporated by reference herein. Those techniques include a common data store for sharing information with members of a group, including a phone book or address book, where the entries or contact lists may be shared among group members or a master phone book can be maintained. 
     The present invention provides a number of user benefits, including the safeguarding of address book information against theft, loss or phone damage. Moreover, the present invention eliminates the need to manually transfer address books when the user changes phones. In addition, users can view and edit the address book online, wherein changes made online are synchronized with the MS  120 . 
     The present invention provides a number of network operator benefits as well. For example, the present invention reassures customers by protecting valuable information, namely their address books. It also has the potential to reduce customer churn. 
     CONCLUSION 
     The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not with this detailed description, but rather by the claims appended hereto.