Abstract:
In according with the teachings of the present invention, a method and apparatus for performing fast call set-up in a wireless network is presented (FIG.  2 ). A number of efficiencies are implemented to diminish the time required for establishing a call in a packet-based network. For example, call initiation ( 224 ) and Base Station Subsystem (BSS- 202 ) resource allocation are performed contemporaneously; radio Link resources and packet resources are initiated contemporaneously ( 242 - 244 ); an A10 interface is established immediately after allocating and connecting packet control function (PCF) resources for a packet data session ( 246 ); and a service connection request ( 254 ) is performed immediately after a channel assignment process ( 250 ) is performed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to communications. Specifically, the setup of a communication call.  
         [0003]     2. Description of the Prior Art  
         [0004]     Conventional communications networks often include packet-switched technology. Although circuit-switched networks were implemented first, they are an older more traditional technology. Packet-switched networks are newer more flexible networks. A wide variety of new applications are being implemented to take advantage of the flexibility of these packet-switched networks.  
         [0005]     In a packet-switched network, packets may take a variety of different paths to arrive at a given destination. A message is first fragmented into packets, communicated across a network, and then combined back into the original message. Since the packets do not all take the same path, packet-switched networks have gained wide acceptance. For example, if a link goes down on a path, the packets can all be re-routed and still reach their destination with minimal effort.  
         [0006]     In general, packet-switched networks are being widely deployed and will continue to be widely deployed in the foreseeable future. However, packet-switched networks are not without their problems and the advent of new technologies and applications highlight some of these problems. For example, one of the slower aspects of a packet-switched communication session is the initial setup of the call. In addition, in many applications, such as push-to-talk, etc., there are times when a full circuit is not required, but instead there is a need to transmit just a few bits. Unfortunately, conventional packet-switched technologies and protocols were not initially designed for these types of applications and, as such, perform poorly when these applications are implemented.  
         [0007]     An example of a conventional implementation of a packet-based network will be shown in  FIG. 1A  and  FIG. 1B .  FIG. 1A  displays a conventional message process flow diagram. In  FIG. 1A , a Mobile Station (MS)  100  is shown. The MS  100  is in communication with a Base Station Subsystem (BSS)  102 . The BSS  102  includes a Base Transceiver Station (BTS)  104  that is in communication with a Base Station Controller (BSC)  106 . The BSC  106  also includes a Call Processor (CP)  108 , a Resource Manager (RM)  120 , and a Routing Agent (RA)  112 . The RA  112  is in communication with an MSC  120  and a Packet Control Function (PCF)  114 . The BSC  106  communicates with a Mobile Switching Center (MSC)  120  and a PCF  114 . The PCF  114  is in communication with an IP network  116 . An Authentication, Authorization, and Accounting (AAA) server  122  may be accessed through the IP network  116 . A PDSN  118  is also in communication with the IP Network  116 .  
         [0008]     In a conventional system, the MS  100  generates an origination message  124 . Origination for routing  126  is performed between the BTS  104  and the RA  112 . The RA  112  communicates the origination to the Mobile Switching Center (MSC)  120 . The MSC  120  conducts a setup conversation  132  with the RA  112 . The RA  112  communicates a resource allocation request  134  to the RM  110 . The RM  110  and the CP  108  allocate resources as shown by  136 . The RM  110  sends a resource allocation response  138  to the RA  112 . The RA  112  communicates a request for call setup  140  to the CP  108 . The CP  108  communicates a response to the call setup  142 . The RA  112  communicates a request to radio link setup  144  to the CP  108 . The CP  108  and the BTS  104  allocate channel resources as shown by  146 . The CP  108  generates a response to radio link setup  148 . A channel assignment process  150  is performed between the CP  108  and the MS  100 . The CP  108  communicates with the Packet Control Function (PCF)  114  to allocate PCF resources for packet data session  152 . The PCF  114  communicates a response to allocate PCF resources for packet data session  154  with the CP  108 .  
         [0009]      FIG. 1B  displays a continuation of the conventional message process flow diagram shown in  FIG. 1A . In  FIG. 1B , the CP  108  communicates with the PCF  114  to request connect PCF resources for packet data session  156 . The PCF  114  communicates with the Packet Data Service Node (PDSN)  118  to setup/connect an A 10  interface  158 . The PCF  114  communicates with the CP  108  to connect PCF resources for packet data session  160 . The RA  112  sends a Service Connect (SC) request  162  to the CP  108 . The CP  108  and the MS  100  perform a service connection/negotiation process  164 . The CP  108  sends a service connection response  166  to the RA  112 . The RA  112  sends a Sat present message  168  to the MSC  120  and, as a result of the foregoing, data  170  may be communicated between the MS  100  and the PDSN  118 .  
         [0010]     It is clear from the foregoing process flow diagram that a number of steps must be accomplished to setup a call in a packet-based network. The various steps require time to setup the call. In addition, many of the steps are required before other steps can be accomplished. The foregoing process results in more cost for the operating network, dissatisfied customers because of the user delay, and ultimately, may even limit the types of applications that can be implemented in the network.  
         [0011]     Thus, there is a need for reducing the time for call setup in a packet-switched network. In addition, there is a need for methods that facilitate the efficient operation of packet-switched networks.  
       SUMMARY OF THE INVENTION  
       [0012]     A method and apparatus is presented that decreases the call setup time for packet-based applications, such as Push-To-Talk (PTT), Voice-over-IP (VoIP), etc. In one embodiment, the call setup time is decreased by enhancing the interface between an MS and BSS.  
         [0013]     In accordance with the teachings of the present invention, the call setup time in a packet network is decreased by performing contemporaneous process execution within a BSS for delay-sensitive packet-based applications, such as PTT and VoIP. In one embodiment, call origination is processed at the same time as the resource allocation in the BSS. In a first embodiment, call origination is processed during user authentication. In a second embodiment, radio link resources and packet resources are allocated at the same time. In a third embodiment, a service connection and/or service negotiation process are performed directly after a channel assignment process. In a fourth embodiment, service connection and/or service negotiation processes are eliminated after a channel assignment process.  
         [0014]     In accordance with the teachings of the present invention, multiple steps are combined into a single step within the BSS as a part of a call setup process for allocating a traffic channel to the MS. In accordance with the teachings of the present invention, packet-based applications are identified and/or remembered and, as such, receive special treatment in the wireless access network so that the MS allocates a traffic channel at the earliest possible time. In an example a unique service option is assigned to a delay-sensitive packet-based applications (such as PTT or VoIP). This service option may be included by the MS in the origination message so that the network may provide a fast call setup service for this specific delay-sensitive packet-based applications (such as PTT or VoIP).  
         [0015]     A method of operating a base station subsystem, comprises the steps of processing a call initiation request; and contemporaneously, allocating resources within the base station subsystem needed to grant network access to a Mobile Station.  
         [0016]     A method of operating a base station subsystem, comprises the steps of allocating radio frequency resources; and contemporaneously, allocating packet session resources.  
         [0017]     A method of operating a wireless network, comprises the steps of establishing an A 10  interface; allocating Packet Control Function resources for a packet data session in response to establishing the A 10  interface; and connecting the PCF resources for the packet data session in response to allocating the PCF resources.  
         [0018]     A method of operating a wireless network, comprises the steps of establishing an A 10  interface; performing a channel assignment process; and initiating a service connection request in response to establishing the A 10  interface and in response to performing the channel assignment process.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1A  displays a conventional message process flow diagram.  
         [0020]      FIG. 1B  displays a continuation of the conventional message process flow diagram shown in  FIG. 1A .  
         [0021]      FIG. 2  displays a message process flow diagram implemented in accordance with the teachings of the present invention.  
         [0022]      FIG. 3  displays a computer architecture implementing the teachings of the present invention. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0023]     While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.  
         [0024]      FIG. 2  displays a message process flow diagram detailing the method and apparatus of the present invention. In one embodiment, the method and apparatus presented may be implemented to establish a packet data call communication circuit for specific delay-sensitive applications, such as PTT, VoIP, etc. In one embodiment, delay-sensitive applications include applications that require end-to-end communication within a certain time to properly operate the application. In accordance with the teachings of the present invention, the call setup time in a packet network is decreased by performing contemporaneous process execution within a BSS for delay-sensitive packet-based applications, such as PTT and VoIP. In one embodiment, contemporaneous process steps include those process steps that are performed simultaneously, relatively simultaneously when compared with the time on other process steps and/or within the same time period when compared with the time period of other steps.  
         [0025]     In  FIG. 2 , a Mobile Station (MS)  200  is shown. The MS  200  is in communication with a Base Station Subsystem (BSS)  202 . The BSS  202  includes a Base Transceiver Station (BTS)  204  that is in communication with a Base Station Controller (BSC)  206 . The BSC  206  also includes a Call Processor (CP)  208 , a Resource Manager (RM)  210 , and a Routing Agent (RA)  212 . The RA  212  is in communication with an MSC  220  and a Packet Control Function (PCF)  214 . The BSC  206  communicates with a Mobile Switching Center (MSC)  220  and a PCF  214 . The PCF  214  is in communication with an IP network  216 . An Authentication, Authorization, and Accounting (AAA) server  222  may be accessed through the IP network  216 . A PDSN  218  is also in communication with the IP Network  216 . It should be appreciated that, in alternate embodiments, the Packet Control Function (PCF)  214  and the PDSN  218  may each function as part of the BSS  202 .  
         [0026]     In one embodiment, the RM  210  is primarily responsible for allocating resources, such as selecting the appropriate CP  208 , memory resources, etc., within the BSC  206 . In one embodiment, the RA  212  is a functional entity within the BSC  206  that is responsible for routing messages within the BSS  202 .  
         [0027]     In one embodiment of the present invention, messages are sent from the MS  200  to the PSDN  218  to establish a communication path for data transmission. The messages and architectures discussed in the instant application are defined in various wireless standards. Among these standards are 3GPP2 Access Network Interfaces Interoperability Specification, A.S0002-A Version 2.0, 3GPP2, http://www.3ipp2.org/Public html/specs/A.S0002-A v2.0. df, Jun. 2002 and Interoperability Specification (IOS) for cdma2000 Access Network Interfaces Part 7-A20 and A22 Interfaces, 3G-IOSv4.3, 3GPP2 A.S0027-A, Version 2.0.2, http://www.3 gpp2.org/Public html/specs/A.S0027-A v2.0.2 222903.pdf, Jul. 2003, which are both incorporated by reference.  
         [0028]     The MS  200  sends a call setup initiation message  224 , such as an origination message, a page response message, a reconnect message, etc., to the BTS  204 . The BTS  204  forwards the call setup initiation message  226  to the RA  212 . The BTS  204  sends a base station acknowledgement message (BS Ack)  234  to the MS  200  indicating that the call setup initiation message  224  has been received.  
         [0029]     Upon receiving the call setup initiation message  226 , the RA  212  identifies the call as a packet data call for a specific packet-based application, such as PTT application, VoIP application, push-to-media, instant messaging, etc., that requires special treatment. In accordance with the teachings of the present invention, the RA  212  performs the following two tasks: 
        a) The RA  212  forwards the call setup origination message  228  to the MSC  220  for further processing, such as authentication shown as  229 , retrieval of user&#39;s profile etc.;     b) The RA  212  communicates a resource allocation request  230  to request that the RM  210  allocates all of the resources needed within the BSC  206  to complete the call setup process; the RM  210  communicates with the CP  208  to allocate resources  232 ; the RM  210  communicates a resource allocation response  236  to the RA  212 .        
 
         [0032]     The RM  210  allocates the appropriate CP  208  resources and communicates an allocate resource message  232  to inform the selected CP  208  module that it has been selected for processing this particular call setup message for the packet-based applications (i.e., such as PTT and VoIP). The MSC  220  replies to the origination message  228  with a setup conversation message  238  that may include the MS&#39;s  200  profile, such as Supplemental Channel (SCH) capability, Short Data Burst (SDB), supported bit, etc. RM  210  communicates a resource allocation response  236  to inform the RA  212  that the appropriate CP  208  module and the other necessary resources within the BSC  206  have been allocated. In one embodiment, the RM  210  provides the identity, such as an IP (Internet Protocol) address of the CP  208  module to the RA  212 . In another embodiment, the RM  210  also provides the software record number of a CP  208  element to the RA  212 .  
         [0033]     The RA  212  identifies the call as a packet data call for specific packet-based applications (such as PTT and VoIP). It, therefore, combines the functions of call setup and radio link setup into a single message before forwarding it to the CP  208 . Using a combined message (i.e., combined request for call and radio link setup  240 ), the CP  208  performs all the necessary tasks needed to setup the call as well as setup the radio link between the MS  200  and the BSS  202 . In this way, the messages between the RA  212  and the CP  208  are minimized to a single message as opposed to multiple messages. In one embodiment, the combined message may include parameters, such as the Quality of Service (QoS) priority, the SDB bit, etc. Upon receiving the combined request for call and radio link setup  240 , the CP  208  may perfonn the following two functions (among other things): 
        a) Using an allocate channel resources message  242 , the CP  208  requests the BTS  204  to allocate the radio link related resources. Radio link related resources include the resources necessary to establish, operate, and terminate a radio link. In a first embodiment, the radio related resources may include a Channel Element (CE), Fundamental Channel (FCH), a FCH Walsh Code, a radio frequency channel, a packet scheduler, a frame processor, a code (such as long code mask, Walsh code etc.) generator, a code (such as long code mask, Walsh code etc.) distributor, radio frequency transmitter, and radio frequency receiver. In addition, the radio link-related resources may include, but are not limited to, the following: hardware and software entities within the BTS  204 , BSC  206 , and PCF  214  that process a packet-based session; software manager (such as PCF manager) to manage such resources; software binding cache to create and maintain co-relationship (also known as software ‘binding’) between the user&#39;s radio-related address, such as International Mobile Subscriber Identity (IMSI), Mobile Identification Number (MIN), Mobile Equipment ID (MEID), etc.; the user&#39;s packet-related address, such as IP address, Network Access Identifier (NAI), Ethernet address, etc.; software session manager to create and maintain the packet session ID, packet session state, R-P session information, etc.; and mobility manager to maintain the mobility information in the packet domain. The CP  208  may also send null frames on the forward FCH as a part of allocating radio link related resources;     b) The CP  208  sends a message (i.e., allocate and connect PCF resources for packet data session message  244 ) to the PCF  214  to request that the PCF  214  allocate appropriate resources (i.e., packet resources) to setup this packet data call for specific packet-based applications (such as PTT and VoIP). Packet resources include the resources necessary to establish, operate, and terminate a packet link. In one embodiment, the packet resources include hardware and software entities within the BSC  206  and PCF  214  to process a packet-based session; software manager (such as PCF manager) to manage such resources; software binding cache to create and maintain co-relationship (also known as software ‘binding’) between the user&#39;s radio-related address, such as International Mobile Subscriber Identity (IMSI), Mobile Identification Number (MIN), Mobile Equipment ID (MEID), etc.; the user&#39;s packet-related address, such as IP address, Network Access Identifier (NAI), Ethernet address, etc.; software session manager to create and maintain the packet session ID, packet session state, R-P session information, etc.; and mobility manager to maintain the mobility information in the packet domain. In one embodiment, the allocated and connected PCF resources for packet data session message  244  may include the transition identification (i.e., to indicate whether the MS  200  is transitioning from Null to Active or Dormant to Active, and/or the MS&#39;s  200  International Mobile Subscriber Identity (IMSI)).        
 
         [0036]     The PCF  214  allocates the appropriate resources necessary to setup the packet data call for specific packet-based applications (such as PTT and VoIP). The PCF  214  resources may include a block of Read Only Memory, a packet session identification (SID), a Port identification (PID), etc. The PCF  214  may then send an All -Resigtration Request message to the PDSN  218  to set up (or re-connect) an A 10  interface as shown by  246  to serve specific packet-based applications (such as PTT and VOIP). The PCF  214  may also create a proprietary A 10  interface between the PCF  214  and the PDSN  218 .  
         [0037]     The PCF  214  communicates allocate and connect PCF resources for packet data session message  248  to the CP  208  to inform the CP  208  that the appropriate resources as well as the A 10  interface have been allocated (or connected) to setup this packet data for specific packet-based applications (such as PTT and VoIP). The CP  208  communicates with the MS  200 , shown with the channel assignment process  250  to complete the channel assignment process between the MS  200  and the BSS  202 . In accordance with the teachings of the present invention, in one embodiment, the channel assignment process  250  may continue simultaneously while the steps of allocate and connect PCF resources for packet data session  244 , setup/connect A 10  interface  246 , and allocate and connect PCF resources for packet data session  248  are being performed. In one embodiment, the channel assignment process  250  may include the CP  208  sending Extended Channel Assignment Message (ECAM) to MS  200  on a paging channel, the assigned CE acquiring reverse FCH, the BTS receiving traffic channel preamble from the MS  200 , the CP  208  receiving null traffic data from the MS  200 , the CP  208  sending BS Ack message  234  to the MS  200 , the MS  200  sending MS Acknowledgement (MS Ack)  234  message to the CP  208 , the CP  208  sending Status Request message to the MS  200  and the MS  200  sending Status Response message to the CP  208 , etc.  
         [0038]     The CP  208  communicates a response to call and radio link setup  252  to inform the RA  212  that the channel has been successfully setup for this packet data call for serving specific applications (such as PTT and VOIP). The RA  212  communicates a Service Connection (SC) request  254  to request that the CP  208  sends a service connect message to the MS  200 . In one embodiment, the SC request  254  includes the user&#39;s zone ID, the user&#39;s network ID, and other location-related information.  
         [0039]     The CP  208  completes the service connect process as shown by  256 . In one embodiment, completing the service connection process  256  includes sending a service connect message to the MS  200  and then receiving a service connect complete message from the MS  200 . The service connect message informs the MS  200  that the call has been setup to serve specific applications (such as PTT and VOIP). In one embodiment, parameters, such as the multiplexing option, coding type, interleaving type, and allowed radio configuration, etc., may be included in the service connect message.  
         [0040]     As shown by the SC response  258 , the CP  208  informs the RA  212  that the MS  200  has been granted access to the BSS  202  to serve specific packet-based applications (such as PTT and VOIP). In one embodiment, the CP  208  informs the RA  212  about MS&#39;s  200  SCH capabilities, SDB supported bit, the PCF  214  address, etc. In another embodiment, the SC request  254 , the service connect process  256 , and SC response  258  can all be omitted to reduce the call setup time. This is done based on the network&#39;s knowledge that the user is currently in the process of launching specific packet-based applications (such as PTT and VoIP).  
         [0041]     The RA  212  sends a Sat present message  260  to the MSC  220  informing the MSC  220  that the MS  200  has been allowed in the network, that is, a traffic channel has been allocated to the MS  200 . In one embodiment, the Sat present message  260  may also inform the MSC  220  of the MS  200  SCH capabilities, SDB supported bits, etc.  
         [0042]     The MS  200  may now launch the specific packet-based applications illustrated by the data  262 . The MS  200  may also establish Radio Link Protocol (RLP) and Point-To-Point (PPP) sessions (not shown in the figure) before launching the specific packet-based applications.  
         [0043]      FIG. 3  displays a computer architecture implementing the teachings of the present invention. The computer  300  may be used to implement the MS  200 , the BSC  206 , the CP  208 , the RM  210 , the RA  212 , MSC  220 , PCF  214 , IP Network  216 , AAA  222 , and the PDSN  218  of  FIG. 2 . A central processing unit (CPU)  302  functions as the brain of the computer  300 . Internal memory  304  is shown. The internal memory  304  includes short-term memory  306  and long-term memory  308 . The short-term memory  306  may be a Random Access Memory (RAM) or a memory cache used for staging information. The long-term memory  308  may be a Read Only Memory (ROM) or an alternative form of memory used for storing information. Storage memory  320  may be any memory residing within the computer  300  other than internal memory  304 . In one embodiment of the present invention, storage memory  320  is implemented with a hard drive. A communication pathway  310  is used to communicate information within computer  300 . In addition, the communication pathway  310  may be connected to interfaces, which communicate information out of the computer  300  or receive information into the computer  300 .  
         [0044]     Input devices, such as tactile input device, joystick, keyboards, microphone, communications connections, or a mouse, are shown as  312 . The input devices  312  interface with computer  300  through an input interface  314 . Output devices, such as a monitor, speakers, communications connections, etc., are shown as  316 . The output devices  316  communicate with computer  300  through an output interface  318 .  
         [0045]     While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.  
         [0046]     It is, therefore, intended by the appended claims to cover any and all such applications, modifications, and embodiments within the scope of the present invention.