Abstract:
Mobile station communication architectures for supporting circuit and packet modes of operation and methods therefor, for example time division multiple access (TDMA) and general packet radio services (GPRS) in a cellular telephone handset. In one exemplary embodiment, the architecture includes a router and operating mode switch ( 108 ) coupled to an RF transceiver ( 112 ), a packet stack ( 102 ) coupled to the RF transceiver, a circuit stack ( 104 ) coupled to the router and operating mode switch and to the packet stack, the RF transceiver, and to the circuit stack coupled to the packet stack, and an interoperability entity ( 106 ) coupled to the router and operating mode switch and to the packet and circuit stacks.

Description:
FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to mobile station communications and, more particularly, to mobile station communication architectures supporting circuit and packet modes of operation, for example, time division multiple access (TDMA) and general packet radio services (GPRS) in a cellular telephone handset. 
     BACKGROUND 
     The deployment of some digital communication system architectures requires mobile stations that support both packet data and circuit service. 
     The EGPRS-136 Class B multi-mode communication system architecture, for example, integrates the TIA/EIA-136 standard air interface, also known as Time Division Multiple Access (TDMA), with the General Packet Radio Service (GPRS) standard specified by the European Telecommunications Standards Institute (ETSI) and the Third Generation Partnership Project (3GPP). 
     The EGPRS-136 Class B architecture supports circuit service (30 KHz TDMA), packet data services on a 200 KHz air interface, teleservices defined in the Global System for Mobile communication (GSM) standards, TIA/EIA-136 teleservices, Intelligent Roaming functions and TIA/EIA-41 short messaging services. 
     The EGPRS-136 Class B mobile station architecture provides for sequential, but not simultaneous, packet data and circuit mode services. Thus when a circuit call is initiated, either by the network or the mobile station, during a packet data transaction, packet data service is interrupted for execution of the circuit call. Thereafter, packet data service resumes upon termination of the circuit call. 
     Integration of packet and circuit architectures, including the EGPRS-136 Class B architecture, in multi-mode mobile stations requires packet and circuit switched mode interoperability. 
     The various aspects, features and advantages of the present invention will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Detailed Description of the invention with the accompanying drawings described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is schematic block diagram of an exemplary mobile station supporting packet and circuit modes of operation. 
         FIG. 2  is a schematic block diagram of an EGPRS-136 mobile station architecture according to an exemplary embodiment of the invention. 
         FIG. 3  is a state diagram illustrating interoperability during a power-up scenario. 
         FIG. 4  is an exemplary packet pause interoperability scenario diagram. 
         FIG. 5  is a packet/circuit mode switching scenario diagram. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a mobile station  100  supporting packet and circuit modes of operation.  FIG. 2  illustrates an exemplary EGPRS-136 multi-mode, mobile station architecture  200  integrating the TIA/EIA-136 standard air interface with the General Packet Radio Service (GPRS) standard specified by the European Telecommunications Standards Institute and the Third Generation Partnership Project. 
     In  FIG. 1 , the mobile station comprises generally a packet stack  102  for supporting packet mode operation, for example EGPRS or other packet data services, and a circuit stack  104  for supporting circuit mode, for example TDMA, or CDMA, or W-CDMA or some other circuit service. In the exemplary EGPRS-136 multi-mode architecture of  FIG. 2 , the packet stack is an EGPRS stack  202 , and the circuit stack is a TDMA stack  204 . 
     In  FIG. 1 , the packet and circuit stacks are coupled to each other for communications therebetween, for example, for communicating among other information a list of packet channels derived from control channel broadcast information with a system identifier. In the exemplary architecture of  FIG. 2 , a list of packet channels derived from Digital Control Channel (DCCH) broadcast information with a system identifier is communicated between the TDMA and EGPRS stacks. 
     In  FIG. 1 , the mobile station  100  comprises an interoperability entity  106  coupled to the packet and circuit stacks for communications therebetween, for example, for communicating mode or state changes, among other information. The interoperability entity  106  and the circuit stack  104  are coupled to a router and operating mode switch  108  for communications therebetween, for example to communicate mode or state changes, among other information. 
     Generally, the interoperability entity comprises a tunneling of messages (TOM) entity and a packet mode circuit mobility management entity. In one embodiment, the TOM entity is coupled to the packet stack for communications therebetween, for example to acknowledge whether circuit control information is transmitted over a packet channel air interface, although this information may be communicated by some other technology. 
     In  FIG. 2 , the interoperability entity comprises a 136 Mobility Management (136MM) entity  206  coupled to a tunneling of messages (TOM) entity  207 . The 136MM entity  206  is also coupled to a router and operating mode switch (MRTS)  208 . The TOM entity  207  is coupled to the EGPRS stack  202 . Particularly, the EGPRS stack comprises an RLC entity  216  coupled to the TOM entity  207 , and a Logical Link Control (LLC) entity  218  coupled to both the TOM entity  207  and to the GMM entity  210 . The EGPRS stack  202  also comprises a connection management entity  220  coupled to the LLC entity  218  and to the GMM entity  210 . 
     Generally, the packet stack comprises a packet mode mobility management entity, and the circuit stack comprises a circuit mode mobility management entity. In the exemplary architecture of  FIG. 2 , for example, the EGPRS stack comprises a GPRS Mobility Management (GMM) entity  210  coupled to the 136MM entity  206 . The TDMA stack  204  comprises a Digital Control Channel Layer 3 Mobility Management (DCCH Layer 3) entity  212  coupled to the GMM entity  210  and to the 136MM entity  206 . The DCCH Layer 3 entity  212  and the 136 MM entity are both coupled to the router and operating mode switch  208 . Packet stack mobility management is provided by the 136MM entity of the interoperability entity. Circuit stack mobility management is provided by the DCCH Layer 3 entity  212 . 
     In  FIG. 1 , the router and operating mode switch  108  is coupled to a user interface  110  comprising inputs and outputs, for example input keys and devices, visual displays, accessory adapters, etc. Generally, the router and mode switch communicates display information from the packet and circuit stacks to the user interface. 
     In  FIG. 1 , display and other information is communicated from the packet and data stacks through the corresponding mobility management entities, to the user interface  110  via the router and mode switch  108 . In the exemplary architecture of  FIG. 2 , for example, display information from the EGPRS and TDMA stacks is communicated via the 136MM and DCCH Layer 3 entities  206  and  212  and the MRTS  208  to the user interface  214 . 
     The mobility management entities also communicate mode and state change information to the router and mode switch  108 . In  FIG. 2 , this information is communicated from the 136MM entity  206  and the DCCH Layer 3 entity  212  to the MRTS  208 . 
     Generally, mode and state change information is communicated between the mobility management entities. In the exemplary architecture of  FIG. 2 , this information is communicated between the 136MM entity  206  and the DCCH Layer 3 entity  212 . The 136 MM entity for example notifies the DCCH Layer 3 entity of changes to TDMA service, circuit page receipts, and call originations. Some of this information is generally sent along with pointers to one or more TDMA control channels derived from information broadcasts on the packet channel. The DCCH Layer 3 entity, for example, notifies the 136MM entity that packet service has been acquired, and that power down has been requested. 
     Packet channel selection information, e.g., success or failure, is communicated between the EGPRS stack and the TDMA stack, and particularly to the DCCH Layer 3 entity  212 . The DCCH Layer 3 entity, for example, sends a list of packet channels derived from broadcast information along with system identifier information to the EGPRS stack. 
     The router and operating mode switch  108  is also coupled to an RF transmitter/receiver (transceiver)  112 . In one embodiment, a single RF transceiver is tunable by a programmable digital signal processor in response to communications from the router and mode switch for operation at different frequencies for packet or circuit mode, depending on whether the mobile station is in packet or circuit mode. In an alternative embodiment, the RF transceiver is controlled by dedicated signal processors, one for circuit mode operation and the other for packet mode operation. 
     In one embodiment, only one circuit mobility management entity is active at any given time, for example, the 136MM entity or the DCCH Layer 3 entity in the exemplary EGPRS-136 Class B mobile station architecture. The active mobility management entity is communicated to the router and mode switch, which accordingly invokes proper tuning of the RF transceiver for the active mode. In the exemplary architecture of  FIG. 2 , for example, the router and operating mode switch  208  configures the RF transceiver and digital hardware for packet or circuit mode and notifies at least one of the 136MM entity and the DCCH Layer 3 entity of the RF transceiver configuration. 
     In the exemplary architecture of  FIG. 2 , the EGPRS stack comprises an RLC entity coupled to the TOM entity for acknowledging whether circuit control information is transmitted over the packet channel air interface. The EGPRS stack comprises a Logical Link Control (LLC)  218  entity coupled to both the TOM entity  207  and to the GMM entity  210 . The EGPRS stack also comprises a connection management entity  220  coupled to the GMM entity  210 . 
       FIG. 3  illustrates interoperability in a mobile station (MS) power-up scenario for the exemplary EGPRS-136 architecture. In this architecture, the MS enters the packet mode through the TIA/EIA-136 Digital Control Channel (DCCH). During power-up, the MS enters the D1 (Null) State and then the D2 DCCH Scanning and Locking State of the TDMA DCCH Layer 3 State Machine in the 136 Plane. At the same time, the MS enters the Null State of the GMM State Machine in the GMM Plane. The MS reads and decodes one or more frequency pointers to packet channels broadcast on the DCCH using TDMA technology, i.e., 30 KHz. Thereafter, the MS executes a packet GPRS cell selection procedure using a list of EGPRS-136 channel pointers along with system identity information, e.g. a PLMN identity. The GMM entity notifies the DCCH State Machine about the packet channel search results. 
     If a packet channel has been found successfully, the MS enters the P3R state of the 136 Mobility Management (P3R 136MM) State Machine that supports the mobility management of the TIA/EIA-41 circuit switched network when the packet channel is present (instead of entering the D3 MM State of the DCCH Layer 3 State Machine illustrated in phantom lines). At the same time, the MS enters a neutral state in the DCCH Layer 3 State Machine, because the circuit switched mobility management has been transferred to the P3R state of the 136MM state machine. If the GPRS cell selection procedure fails to find a packet channel, the MS transfers to the DCCH Layer 3 State Machine where it operates as a voice only TDMA device. 
     From the P3R 136MM state, the MS activates a GPRS packet service attachment procedure. Upon successful attachment to the packet service, the MS changes state to the P3U 136MM State. Because the MS is physically tuned to the packet control channel (200 kHz PCCH, GMSK/8PSK modulation), the tunneling of messages (TOM) mechanism is used to deliver the circuit switched signaling and teleservices from/to the MS. 
     From the P3U 136MM State, the MS registers within the TDMA circuit switched network using the TOM mechanism. After registration with the circuit network, the MS co-exists in the 136MM plane and the GMM Plane. The 136 Plane supports signaling and teleservices for the circuit switched activity, and the GMM Plane controls the management for the packet network. In the EGPRS-136 architecture, the MS camps on the packet channel until an interoperability scenario occurs. 
       FIG. 4  illustrates a packet pause interoperability scenario for the EGPRS-136 architecture. In one embodiment, when the MS, which is physically tuned to the 200 KHz packet channel, receives a page for establishment of a TIA/EIA-136 circuit switched connection, packet activity is interrupted, or paused. 
     In  FIG. 4 , the MS is paged with a PACKET PAGING REQUEST message. Upon receipt of the REQUEST message, the MS sends a PACKET CHANNEL REQUEST message indicating “Single block without TBF establishment” to the Base Station System (BSS). 
     In  FIG. 4 , a radio resource assignment is assigned by the BSS to the MS in the PACKET UPLINK ASSIGNMENT message. The PACKET UPLINK ASSIGNMENT message from the BSS is sent on any Packet Access Grant Channel (PAGCH) on the same packet common control channel (PCCCH) on which the network has received the PACKET CHANNEL REQUEST message from the MS. 
     In one embodiment, upon sending the PACKET CHANNEL REQUEST message, the MS starts a timer, for example a 1 second timer. If the timer expires before a PACKET UPLINK ASSIGNMENT message from the BSS is received, the packet access procedure is aborted, and the MS tunes to the DCCH for circuit switched operations. 
     In  FIG. 4 , when receiving a PACKET UPLINK ASSIGNMENT message, the MS sends an RLC/MAC PACKET PAUSE message in the allocated radio block on the assigned Packet Data Channel (PDCH). No Temporary Block Flow (TBF) is established and the network does not acknowledge reception of the PACKET PAUSE message. The Base Station System (BSS) sends a GMM suspend message to the Serving GPRS Support Node (SGSN) using the Base Station GPRS Protocol (BSSGP). The SGSN acknowledges the GMM SUSPEND request by sending the BSS a GMM SUSPEND-ACK message. After sending the PACKET PAUSE REQUEST message, the MS tunes to the 30 kHz TDMA DCCH and establishes a circuit switched connection, whereupon MS DCCH Layer 3 mobility management is active. 
       FIG. 5  illustrates a mode-switching scenario in response to an incoming circuit page in the exemplary EGPRS-136 mobile station architecture. When the MS is paged, the page is sent to the GRR entity or layer at  501 . At  502 , the GPRS Radio Resource (GRR) entity decodes the page and delivers it to the GMM entity, which in turn notifies the 136MM entity of receipt of the circuit page at  503 . The 136MM entity sends a pause request to the GMM entity requesting suspension of packet data operations at  504 . The GMM entity notifies the GRR entity and the packet pause procedure is invoked at  505 . In response to the message from the GMM entity, the GRR entity constructs a resource request, which is sent to the BSS at  506 . At  507 , the network replies with a resource assignment to the GRR. Upon receiving the resource assignment, the GRR triggers a packet pause request, which is sent to the BSS at  508 . The GRR entity also notifies the GMM entity that the packet pause request has been sent at  509 . At  510 , the GMM entity issues a primitive that suspends the Logical Link Control (LLC). At  511 , the GMM entity notifies the 136MM entity that the packet pause request has issued, and the 136MM entity sends the mode change request to the router and mode switch (MRTS) at  512 . The MRTS communicates with the digital hardware, which triggers re-programming of the hardware and the RF transceiver at  513 . At  514 , the MRTS receives confirmation that the digital hardware has been re-programmed, and at  515  the MRTS notifies the 136MM entity of the change. At  516 , the 136MM entity notifies the DCCH Layer 3 entity that the MS has been paged by the network and sends a list of the possible DCCH channel numbers along with other information for finding circuit service. At  517 , the 136MM entity notifies the MRTS of state changes, and at  518  the DCCH Layer 3 entity notifies the MRTS of state changes. 
     While the present disclosure and what is considered presently to be the best modes thereof have been described in a manner that establishes possession thereof by the inventors and that enables those of ordinary skill in the art to make and use the same, it will be understood and appreciated that there are many equivalents to the exemplary embodiments disclosed herein and that myriad modifications and variations may be made thereto without departing from the scope and spirit of the inventions, which are to be limited not by the exemplary embodiments but by the appended claims.