Abstract:
A method of terminating a packet data call at a target mobile station (MS) operating in the wireless network. The method comprises the steps of: i) receiving in a PDSN of the wireless network first packet data directed to the target MS; ii) identifying in the first packet data a mobile identification number of the target MS; iii) using the mobile identification number to retrieve an IP address of the target mobile station from a first database of the PDSN; and iv) forwarding the first packet data to the target mobile station using the retrieved IP address. The method further comprises the step of determining from a second database of the PDSN a target PCF unit and a target base station controller with which the target MS is currently in communication.

Description:
TECHNICAL FIELD OF THE INVENTION  
       [0001]     The present invention generally relates to packet data services in wireless networks and, more specifically, to a wireless network that allows packet data call termination at a mobile station and packet data calls between mobile stations.  
       BACKGROUND OF THE INVENTION  
       [0002]     Wireless communication systems have become ubiquitous in society. Business and consumers use a wide variety of fixed and mobile wireless terminals, including cell phones, pagers, Personal Communication Services (PCS) systems, and fixed wireless access devices (i.e., vending machine with cellular capability). Wireless service providers continually try to create new markets for wireless devices and expand existing markets by making wireless devices and services cheaper and more reliable. The price of wireless devices has decreased to the point where these devices are affordable to nearly everyone and the price of a wireless device is only a small part of the total cost to the user (i.e., subscriber). To continue to attract new customers, wireless service providers are implementing new services, especially digital data services that, for example, enable a user to browse the Internet and to send and receive e-mail.  
         [0003]     Conventional wireless networks provide packet data call services using control signals that connect the base station (BS) serving the mobile station (MS) that originates a packet data call to a packet data serving node (PDSN). All data transmitted by the source mobile station is transferred through the PDSN into a packet data network, such as the Internet. Unfortunately, conventional wireless networks do not support packet data call services in which the packet data call is terminated on a mobile station. Prior art mobile stations are only capable of originating packet data calls.  
         [0004]     Therefore, there is a need for packet data services in a wireless network that are more flexible and more user-friendly. In particular, there is a need in the art for wireless networks that support mobile station-terminated packet data services. More particularly, there is a need for wireless networks that provide mobile station-to-mobile station (MS-MS) packet data connections.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention provides a wireless network that allows packet data call termination at a mobile station. Advantageously, this facilitates mobile station-to-mobile station (MS-MS) packet data call services.  
         [0006]     To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide, for use in a wireless network, a method of terminating a packet data call at a target mobile station operating in the wireless network. According to an advantageous embodiment of the present invention, the method comprises the steps of: i) receiving in a packet data server node of the wireless network first packet data directed to the target mobile station; ii) identifying in the first packet data a mobile identification number associated with the target mobile station; iii) using the mobile identification number to retrieve an IP address of the target mobile station from a first database associated with the packet data server node; and iv) forwarding the first packet data to the target mobile station using the retrieved IP address.  
         [0007]     According to one embodiment of the present invention, the method further comprises the step of determining from a second database associated with the packet data server node a target packet controller function unit with which the target mobile station is currently in communication.  
         [0008]     According to another embodiment of the present invention, the method further comprises the step of determining from the second database associated with the packet data server node a target base station controller with which the target mobile station is currently in communication.  
         [0009]     According to still another embodiment of the present invention, the method further comprises the step of transmitting a Registration Request message from the packet data server node to the target base station controller, the Registration Request message capable of causing the target base station controller to establish a first traffic channel to the target mobile station.  
         [0010]     According to yet another embodiment of the present invention, the method further comprises the step of transmitting a Registration Response message from the target base station controller to the packet data server nodes after the first traffic channel has been established.  
         [0011]     According to a further embodiment of the present invention, the method further comprises the step of establishing a Point-to-Point Protocol (PPP) connection between the packet data server node and the target mobile station.  
         [0012]     According to a still further embodiment of the present invention, the method further comprises the step of receiving in the packet data server node subsequent packet data directed to the target mobile station and adding the IP address of the target mobile station to the received subsequent packet data.  
         [0013]     According to a yet further embodiment of the present invention, the method further comprises the step of transmitting the received subsequent packet data from the packet data server node to the target mobile station via the PPP connection.  
         [0014]     Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:  
         [0016]      FIG. 1  illustrates a wireless network that provides enhanced packet data services between mobile stations according to the principles of the present invention;  
         [0017]      FIG. 2  illustrates selected portions of the wireless network in  FIG. 1  in greater detail according to the principles of the present invention; and  
         [0018]      FIG. 3  is a message flow diagram illustrating the termination of a call connection on a base station in the wireless network according to the principles of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]      FIGS. 1 through 3 , discussed below, and the various embodiments used to describe the principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the present invention may be implemented in any suitably arranged wireless network.  
         [0020]      FIG. 1  illustrates exemplary wireless network  100 , which provides enhanced packet data services between mobile stations according to the principles of the present invention. Wireless network  100  comprises a plurality of cell sites  121 - 123 , each containing one of the base stations, BS  101 , BS  102 , or BS  103 . Base stations  101 - 103  communicate with a plurality of mobile stations (MS)  111 - 114  over code division multiple access (CDMA) channels according to the IS-2000-C standard (i.e., Release C of cdma2000). Mobile stations  111 - 114  may be any suitable wireless devices, including conventional cellular radiotelephones, PCS handset devices, personal digital assistants, portable computers, telemetry devices, and the like, which are capable of communicating with the base stations via wireless links.  
         [0021]     The present invention is not limited to mobile devices. Other types of wireless access terminals, including fixed wireless terminals, may be used. For the sake of simplicity, only mobile stations are shown and discussed hereafter. However, it should be understood that the use of the term “mobile station” in the claims and in the description below is intended to encompass both truly mobile devices (e.g., cell phones, wireless laptops) and stationary wireless terminals (e.g., monitoring devices with wireless capability).  
         [0022]     Dotted lines show the approximate boundaries of the cell sites  121 - 123  in which base stations  101 - 103  are located. The cell sites are shown approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the cell sites may have other irregular shapes, depending on the cell configuration selected and natural and man-made obstructions.  
         [0023]     As is well known in the art, cell sites  121 - 123  are comprised of a plurality of sectors (not shown), where a directional antenna coupled to the base station illuminates each sector. The embodiment of  FIG. 1  illustrates the base station in the center of the cell. Alternate embodiments position the directional antennas in corners of the sectors. The system of the present invention is not limited to any particular cell site configuration.  
         [0024]     In one embodiment of the present invention, BS  101 , BS  102 , and BS  103  comprise a base station controller (BSC) and at least one base transceiver subsystem (BTS). Base station controllers and base transceiver subsystems are well known to those skilled in the art. A base station controller is a device that manages wireless communications resources, including the base transceiver subsystems, for specified cells within a wireless communications network. A base transceiver subsystem comprises the RF transceivers, antennas, and other electrical equipment located in each cell site. This equipment may include air conditioning units, heating units, electrical supplies, telephone line interfaces and RF transmitters and RF receivers. For the purpose of simplicity and clarity in explaining the operation of the present invention, the base transceiver subsystem in each of cells  121 ,  122 , and  123  and the base station controller associated with each base transceiver subsystem are collectively represented by BS  101 , BS  102  and BS  103 , respectively.  
         [0025]     BS  101 , BS  102  and BS  103  transfer voice and data signals between each other and the public switched telephone network (PSTN) (not shown) via communication line  131  and mobile switching center (MSC)  140 . BS  101 , BS  102  and BS  103  also transfer data signals, such as packet data, with the Internet (not shown) via communication line  131  and packet data server node (PDSN)  150 . Packet control function (PCF) unit  190  controls the flow of data packets between base stations  101 - 103  and PDSN  150 . PCF unit  190  may be implemented as part of PDSN  150 , as part of base stations  101 - 103 , or as a stand-alone device that communicates with PDSN  150 , as shown in  FIG. 1 . Line  131  also provides the connection path to transfer control signals between MSC  140  and BS  101 , BS  102  and BS  103  used to establish connections for voice and data circuits between MSC  140  and BS  101 , BS  102  and BS  103 .  
         [0026]     Communication line  131  may be any suitable connection means, including a T1 line, a T3 line, a fiber optic link, or any other type of data connection. The connections on line  131  may transmit analog voice signals or digital voice signals in pulse code modulated (PCM) format, Internet Protocol (IP) format, asynchronous transfer mode (ATM) format, or the like. According to an advantageous embodiment of the present invention, line  131  also provides an Internet Protocol (IP) connection that transfers data packets between the base stations of wireless network  100 , including BS  101 , BS  102  and BS  103 . Thus, line  131  comprises a local area network (LAN) that provides direct IP connections between base stations without using PDSN  150 .  
         [0027]     MSC  140  is a switching device that provides services and coordination between the subscribers in a wireless network and external networks, such as the PSTN or Internet. MSC  140  is well known to those skilled in the art. In some embodiments of the present invention, communications line  131  may be several different data links where each data link couples one of BS  101 , BS  102 , or BS  103  to MSC  140 .  
         [0028]     In the exemplary wireless network  100 , MS  111  is located in cell site  121  and is in communication with BS  101 . MS  113  is located in cell site  122  and is in communication with BS  102 . MS  114  is located in cell site  123  and is in communication with BS  103 . MS  112  is also located close to the edge of cell site  123  and is moving in the direction of cell site  123 , as indicated by the direction arrow proximate MS  112 . At some point, as MS  112  moves into cell site  123  and out of cell site  121 , a handoff will occur.  
         [0029]     According to the principles of the present invention, wireless network  100  provides packet data services and wireless networks  100  is capable of terminating packet data calls at a mobile station. Advantageously, this allows a packet data call connection to be set up from a source (or originating) mobile station to a target (or destination) mobile station. This capability if useful for implementing, for example, a voice-over-IP (VoIP) application. Implementing the present invention requires changes to the functionality of packet control function (PCF) unit  190  and packet data server node (PDSN)  150 .  
         [0030]      FIG. 2  illustrates selected portions of wireless network  100  in greater detail according to the principles of the present invention. Packet control function (PCF) unit  190  comprises A 10 /A 11  interface (IF) controller  210  and packet data server node (PDSN)  150  comprises A 10 /A 11  Interface (IF) controller  220 . A 10 /A 11  IF controller  210  has been modified to include packet data termination function  215 . Similarly, A 10 /A 11  IF controller  220  has been modified to include packet data termination function  225 . Packet data termination function  215  and packet data termination function  225  enable A 10 /A 11  IF controller  210  and A 10 /A 11  IF controller  220  to terminate a packet data call on a mobile station, a capability that is absent in the prior art.  
         [0031]     In order to terminate the call at a mobile station, the address of the terminating mobile station must be known. The address may be the mobile identification number (MIN) of the terminating mobile station or the IP address of the terminating mobile station. According to an exemplary embodiment of the present invention, PDSN  150  accesses a database that maps the MIN (e.g., IMSI value) of a mobile station to the IP address of the mobile station. This database is represented by MIN-to-IP address mapping database  240 . MIN-to-IP address mapping database  240  may be directly coupled to PDSN  150 . Alternatively, PDSN  150  may access remotely disposed MIN-to-IP address mapping database  240  via the Internet.  
         [0032]     According to an exemplary embodiment of the present invention, PDSN  150  also accesses a database that tracks the local BSC and/or local PCF unit with which each active mobile station is currently communicating. This database is represented by MS location BSC/PCF tracking database  250 . MS location BSC/PCG tracking database  250  may be directly coupled to PDSN  150 . Alternatively, PDSN  150  may access remotely disposed MS location BSC/PCF tracking database  250  via the Internet.  
         [0033]      FIG. 3  depicts message flow diagram  300 , which illustrates the termination of a call connection on a base station in wireless network  100  according to the principles of the present invention. In  FIG. 3 , it is assumed that source mobile station (MS)  111  is originating a packet data call that is to be terminated on target mobile station (MS)  340 . However, those skilled in the art will understand that this is not required. In alternate embodiments, some other processing system, such as a server or personal computer (PC), may originate a packet data call connection that is to be terminated on target MS  340 .  
         [0034]     Also, for the sake of simplicity, it is assumed that the packet control function (PCF) unit is part of the base station controller (BSC). Hence, the PCF unit and the BSC associated with source MS  111  are collectively represented as source BSC/PCF  320  and the PCF unit and the BSC associated with target MS  340  are collectively represented as target BSC/PCF  330 .  
         [0035]     Initially, the user of source mobile station (MS)  111  originates a packet data call that will be terminated on target mobile station (MS)  340  by dialing the mobile identification number (MIN) of target MS  340 . According to conventional IS-2000 protocol, source MS  111  transmits Origination message  301  to the base station in source BSC/PCF  320 , which responds by transmitting a Base Station Acknowledgement (BS ACK) Order message  302  back to source MS  111 . The base station of source BSC/PCF  320  also transmits CM Service Request message  303  to MSC  140 , which responds by transmitting Assignment Request message  304  back to source BSC/PCF  320 . Thereafter, the base station portion of source BSC/PCF  320  and source MS  111  execute IS-2000 traffic channel (TCH) setup procedure  305 .  
         [0036]     After traffic channel setup is complete, the BSC portion of BSC/PCF  320  triggers A 10 /A 11  connection setup procedure  306  with PDSN  150 . Source MS  111  also transmits Assignment Complete message  307  to MSC  140 . Unlike conventional IS-2000 protocol messages, the A 11  Registration message according to the principles of the present invention contains the dialed digits (MIN) of target MS  340 . PDSN  150  accesses MS location BSC/PCF tracking database  250  to determine the PCF and BSC with which target BS  340  is currently communicating (i.e., network location). PDSN  150  also accesses MIN-to-IP address mapping database  240  to map the dialed digits of target MS  340  to the IP address associated with target MS  340 .  
         [0037]     Next, PDSN  150  transmits Registration Request message  308  to target BSC/PCF  330  associated with target MS  340 . Then, the BSC portion of target BSC/PCF  330  transmits sends BS Service Request message  309  to MSC  140 . MSC  140  responds by transmitting BS Service Response message  310  to the BSC portion of target BSC/PCF  330 . MSC  140  also transmits Page Request message  311  to target MS  340 . Target MS  340  responds by transmitting Page Response message  312  to MSC  140 . MSC  312  then transmits Assignment Request message  313  to the BSC portion of target BSC/PCF  330 . Thereafter, the BSC portion of target BSC/PCF  330  and target MS  340  execute IS-2000 traffic channel (TCH) setup procedure  314 .  
         [0038]     Once traffic channels are established for target MS  340 , target BSC/PCF  330  transmits Registration Response message  315  to PDSN  150 . Target BSC/PCF  330  also transmits Assignment Complete message  316  to MSC  140 . At this point, a point-to-point protocol (PPP) connection is established between target MS  340  and PDSN  150 . Active packet data session  317  indicates that source MS  111  transmits to PDSN  150  IP packets that have the destination address of PDSN  150 , and PDSN  150  then forwards the IP packets from source MS  111  to target MS  340 .  
         [0039]     One application of the present invention that is particularly useful is VoIP (Voice Over IP). In VoIP, the source mobile station makes the call to other user to talk. The VoIP application is a packet data application where the call is initiated using either S 033  or S 060 /SO 61 . The caller is unaware that the call is packet data call. Just like for other types of voice calls, the user dials the number of the target mobile station. Under that scenario, the packet data call must terminate on a target mobile station.  
         [0040]     Although the present invention has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present invention encompass such changes and modifications as fall within the scope of the appended claims.