Abstract:
A DBDM (dual band dual mode) terminal is provided for supporting different packet frame modes and a supporting method thereof. This may be provided by mounting a data communication protocol (TCP/UDP/IP/PPP) supporting different communication networks onto a video chip having application of packet data services of the DBDM terminal. It therefore may be possible to remove communication protocols of modem chips for different communication networks applied to a DBDM terminal. Accordingly, consistency of communication protocol may be maintained by using the same communication protocol in different communication networks, and performance of a terminal may also be improved by making application of a packet data service interwork directly with a socket. In addition, by mounting a communication protocol on a video chip, debugging can be easily performed during development.

Description:
The present application claims priority from Korean Patent Application No. 25462/2000, filed Apr. 22, 2003, the subject matter of which is incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a mobile communication terminal, and in particular to a DBDM (dual band dual mode) terminal supporting different packet frame modes. 
   2. Background of the Related Art 
   Due to the expanding usage range of mobile stations and increasing demand for high speed data communication, there has been a limit for supporting various data communication services with present CDMA (code division multiple access) networks as second generation wireless communication networks. 
   Accordingly, WCDMA (wideband code division multiple access) networks have been introduced as a third generation communication network for supporting various data communication services and high speed data communication. However, because the third generation communication network has been presently installed by way of example, a DBDM (dual band dual mode) terminal has been developed that uses the third generation communication network in an area in which a pertinent third generation communication network is installed and uses the existing second generation communication network in the third generation communication network-installed area. 
   The DBDM terminal may include a CDMA modem chip, a WCDMA modem chip and a video chip. More specifically, the terminal may include a total of three processors and an interface among the processors. 
   The video chip performs a function of a master control program for controlling a UI (user interface) (not shown) of a mobile station and includes applications of packet data services such as a VOD (video on demand), a WAP (wireless application protocol) and a MMS (multimedia message service). 
   In the CDMA modem chip, communication protocols (TCP/UDP/IP/PPP) for processing a CDMA protocol stack and packet data are provided. In addition, in order to interwork with application of a packet data service of the video chip, a socket API (application program interface) is mounted onto a TCP/UDP superior layer. 
   In CDMA networks, data communication is performed between a terminal and a base station by using PPP (point to point protocol) frames. Accordingly, in the case of performing communication by using PPP frames in the CDMA network, the DBDM terminal performs data communication by using the CDMA modem chip. 
   When the DBDM terminal receives data from the CDMA network, the CDMA modem chip processes PPP frames received from the CDMA network into IP packets according to the built-in communication protocols (TCP/UDP/IP/PPP) and transmits the IP packets to the video chip. In addition, when the terminal transmits data in the CDMA network, the CDMA modem chip converts the IP packets received from the video chip into PPP frames according to the built-in communication protocols (TCP/UDP/IP/PPP) and transmits them through the CDMA network. 
   In the WCDMA modem chip, communication protocols TCP/UDP/IP/PPP) for processing the WCDMA protocol stack and packet data are provided. In addition, similar to the CDMA modem chip, in order to interwork with applications of the packet data service of the video chip, a socket API (application program interface) is mounted onto a TCP/UDP superior layer. 
   In the case of performing data communication in the WCDMA network, both PPP and IP (internet protocol) frames are supported between a terminal and a base station. In the WCDMA network, because it is appropriate to communicate with IP frames in performance and expense aspects, communication is generally performed by using IP frames, as occasion demands, and IP frames and PPP frames are mutually converted and used. 
   In the above-mentioned DBDM terminal, because data communication protocols exist in a modem chip supporting each network and different protocols are used according to the WCDMA and CDMA networks, when a packet data service is implemented, an additional interface for interworking a socket with a modem chip according to each network is required. In addition, because it is difficult to interwork applications of all packet data services directly with a socket, performance of a terminal may be lowered, and all communication protocols of the WCDMA modem chip and the CDMA modem chip have to be debugged when the terminal has a problem. 
   SUMMARY OF THE INVENTION 
   An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter. 
   In order to solve the above-mentioned problems, an object of the present invention may be to provide a DBDM (dual band dual mode) terminal supporting different packet frame modes and a supporting method thereof capable of maintaining protocol use consistency in different communication networks. 
   Another object of the present invention may be to improve performance of a terminal by directly interworking with a socket and facilitated debugging of a data communication protocol by mounting a data communication protocol (TCP/UDP/IP/PPP) supporting both CDMA (code division multiple access) and WCDMA (wideband code division multiple access) on a video chip of a DBDM terminal in order to make a CDMA modem chip and a WCDMA modem chip perform only a modem function. 
   In order to achieve the above-mentioned objects, a dual mode terminal supporting different packet frame modes may include a video chip having an application of packet data services and second and third generation data communication protocol; a second generation network modem chip which is connected with the video chip through an interface and has a protocol stack about a second generation communication network; and a third generation network modem chip which is connected with the video chip through an interface and has a protocol stack about a third generation communication network. 
   In a DBDM (dual band dual mode) terminal, a method for supporting different packet frame modes may include judging a present system mode by using a terminal including a video chip having a second generation and third generation data communication protocol; transmitting packet data to a pertinent network according to a system mode; and receiving packet data from the pertinent network. 
   The packet data transmitting step may include transmitting a pertinent IP frame to the third generation network by transmitting the IP frame passing IP packet processing directly to a third generation modem chip according to a system mode. 
   The packet data transmitting step may include transmitting an IP frame passing IP packet processing to a PPP protocol, converting it into a PPP frame, transmitting the PPP frame to a second generation network modem chip and transmitting the pertinent PPP frame to the second generation network according to a system mode. 
   The packet data receiving step may include transmitting an IP frame received from the third generation network to a video chip when packet data is received from the third generation communication network, transmitting the received IP frame from the video chip to an IP protocol in order to perform packet processing and operating application of the pertinent packet data service. 
   The packet data receiving step may include transmitting a PPP frame received from the second generation network to a video chip when packet data is received from the second generation communication network, converting the PPP frame into an IP frame and performing packet processing in the video chip and operating application of the pertinent packet data service. 
   Additional advantages, objects, features and embodiments of the invention may be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein: 
       FIG. 1  is a block diagram illustrating packet data communication of a DBDM (dual band dual mode) terminal in accordance with an embodiment of the present invention; 
       FIG. 2  illustrates a packet data call set-up procedure of the DBDM (dual band dual mode) terminal in accordance with an embodiment of the present invention; 
       FIG. 3  illustrates a packet data call disconnection procedure of the DBDM (dual band dual mode) terminal in accordance with an embodiment of the present invention; and 
       FIG. 4  illustrates a packet data send/receive procedure of the DBDM (dual band dual mode) terminal in accordance with an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  is a block diagram illustrating packet data communication of a DBDM (dual band dual mode) terminal in accordance with an embodiment of the present invention. As depicted in  FIG. 1 , the DBDM terminal supporting different packet frame modes includes a video chip  10  having application of packet data services and a protocol for second and third generation network data communication; a second generation network modem chip  20  communicating with the video chip  10  through a UART (universal asynchronous receiver transmitter) IPC (interprocessor communication) interface  25  and having a protocol stack  22  about a second generation communication network in order to perform a modem function only for the pertinent network; and a third generation network modem chip  30  communicating with the video chip  10  through a DPRAM (dual port RAM) IPC (interprocessor communication) interface  35  and having a protocol stack  32  about a third generation communication network in order to perform a modem function only for the pertinent network. 
   The video chip  10  and the CDMA modem chip  20  send/receive PPP frames used for packet data communication in the second generation communication network through the UART IPC interface  25 , and the video chip  10  and the WCDMA modem chip  30  send/receive IP frames used for packet data communication in the third generation communication network through the DPRAM IPC interface  35 . 
   The video chip  10  performs a master control program function for controlling a UI (user interface) (not shown) of a mobile station, and includes applications of packet data services such as a VOD (video on demand), a WAP (wireless application protocol) and a MMS (multimedia message service) and also includes data communication protocols (TCP/UDP/IP/PPP)  12 ,  13  usable in CDMA and WCDMA. 
   Different communication protocols have been mounted on modem chips according to specific communication networks. However, only one data communication protocol is mounted on the video chip  10 . Each modem chip  20 ,  30  uses the data communication protocol (TCP/UDP/IP/PPP) by communicating with the video chip  10  through the interface  25 ,  35  respectively, and a packet processed through the data communication protocol (TCP/UDP/IP/PPP)  12 ,  13  of the video chip  10  can be interworked with the socket of the TCP/IP superior layer and provided to the packet application  11 . Accordingly, an additional socket interworking interface may not be required for the CDMA modem chip  20  and the WCDMA modem chip  30 . 
   Additionally internal communication may be performed with IP frames having a high speed, using the CDMA network in which communication is performed by using PPP frames, the video chip  10  including a PPP protocol  13 . When IP frames are transmitted in the CDMA network, the IP frames can be transmitted to the CDMA modem chip  20  by being converted into PPP frames through the PPP protocol  13 , and the PPP frame received from the CDMA modem chip  20  can be converted again into the IP frames. 
   Accordingly, the DBDM terminal in accordance with the present invention performs communication internally by using IP frames which have advantages in expense and processing speed aspects. In the case of PPP frame communication having relatively low speed, communication is performed by converting IP frames through the PPP protocol  13  and a serial communication port of the CDMA modem chip  20 . For the PPP frame communication, the video chip  10  and the CDMA modem chip  20  respectively include a UART driver  14 ,  21  for serial communication, and the UART drivers  14 ,  21  are connected through a UART IPC (inter processor communication)  25 . Although a serial communication method is used, the PPP packet data service is not interrupted because the PPP packet data service has a relatively low speed. 
   The video chip  10  can process communication with the WCDMA network smoothly. The video chip  10  internally processes IP packets as IP frames, and provides a pertinent IP frame to the WCDMA modem chip  30  at a high rate of speed through the existing DPRAM interface  35 . The video chip  10  also provides an IP frame received through the WCDMA modem chip  30  to the IP protocol  12  directly. In that case, the video chip  10  and the WCDMA modem chip  30  require IPC drivers  15  and  31  respectively, to sustain communication. 
   Furthermore, the CDMA modem chip  20  and the WCDMA modem chip  30  perform only functions of a modem having a protocol stack  22 ,  32  about each network respectively. The CDMA modem chip  20  and the WCDMA modem chip  30  co-own the IP/PPP protocol mounted on the video chip  10 . 
   Accordingly, as described-above, direct socket interworking with the applications of the packet data services is possible so as to improve performance. By debugging only the protocols  12 ,  13  of the video chip  10  in development, debugging efficiency may be improved. In addition, by using the same protocol, consistency of data communication protocol is maintained. 
   Actual packet data call processing in accordance with an embodiment of the present invention will be described. 
     FIG. 2  illustrates a packet data call set-up procedure of the DBDM (dual band dual mode) terminal in accordance with an embodiment of the present invention. More specifically, a UI (user interface)  40  provides a user&#39;s key input and various displays, and a TE (terminal equipment) as the video chip  10  performs packet data service application and control of the UI and has a dual mode protocol. A MT (mobile terminal) may be a CDMA modem chip  20  or a WCDMA modem chip  30  for performing a modem function about each network. There components are included in an MS (mobile station)  100 . The MS  100  performs packet data communication with the CDMA/WCDMA network  200 . 
   In order to perform packet data call connection, when a user presses a “send” key by operating the UI  40 , the video chip  10  checks a present system mode and performs call connection according to the check result. In the case of a service using the WCDMA communication network, call connection to the WCDMA network is performed. Similarly, in the case of a service using the CDMA communication network, call connection to the CDMA network is performed. 
   First, in the case of IP packet data communication using the WCDMA network, the video chip  10  having a pertinent protocol notifies the WCDMA modem  30  of a call originate with an IP frame. The WCDMA modem  30  transmits a service request signal to the WCDMA network. When the service request is accepted by the WCDMA network, in order to activate a PDP (packet data protocol) context, the WCDMA modem  30  transmits an activate PDP context request signal to the network  200 . The WCDMA modem  30  receives an activate PDP context accept signal as a reply to the request signal. 
   The terminal requests the network to perform the process for activating a PDP context between the terminal and the network, and that process is allocating an IP address and setting resources between the terminal and the network. 
   When the PDP context is activated, a PS_EVENT_CALL_CONNECT_E signal is transmitted to the video chip  10  in order to notify the video chip  10  of the call setup. The video chip  10  finishes the call setup by transmitting a PS CALL CONNECTED signal to the user interface  40 . 
   In the case of PPP packet data communication using the CDMA network, the video chip  10  having the pertinent protocol notifies the CDMA modem  20  of the call originate with a PPP frame converted from an IP frame. The CDMA modem  20  transmits a call setup request to the CDMA network  200 . After receiving a service connect signal from the network  200 , the CDMA modem  20  transmits a PS_EVENT_CALL_CONNECT_E signal to the video chip  10 , and accordingly, a PPP (point-to-point protocol) is set between the video chip  10  and the network  200 . The video chip  10  finishes the call setup by transmitting a PS CALL CONNECTED signal to the user interface  40 . 
     FIG. 3  illustrates a packet data call disconnection procedure of the DBDM (dual band dual mode) terminal in accordance with an embodiment of the present invention. 
   First, when a user presses an “end” key, the video chip  10  checks and performs a packet data call release procedure about a pertinent network. 
   In case of the WCDMA network, the video chip  10  notifies the WCDMA modem  30  of call release according to control about the user interface  40 . The WCDMA modem  30  transmits a deactivate PDP context request signal to the network  200 , and the WCDMA modem  30  receives the deactivate PDP context accept signal from the network  200 . A radio access bearer between the terminal  100  and the network  200  is released. The WCDMA modem  30  notifies the video chip  10  of call release by transmitting a PS_EVENT_CALL_RELEASE_E signal to the video chip  10 , and the video chip  10  transmits a PS CALL DISCONNECTED signal to the user interface  40  and finishes the call release. 
   In the case of the PPP packet data communication using the CDMA network, when PPP hang up is performed between the video chip  10  and the network  200 , the video chip  10  having the pertinent protocol notifies the CDMA modem  20  of call release with a PPP frame converted from an IP frame, and the CDMA modem chip  20  requests a call disconnect to the network  200 . The CDMA modem chip  20  receives the call release signal from the network  200  and notifies the video chip  10  of the call release by transmitting a PS_EVENT_CALL_RELEASE_E signal to the video chip  10 . The video chip  10  transmits a PS CALL DISCONNECTED signal to the user interface  40  and finishes the call release. 
   A data transmitting/receiving process of the DBDM terminal in the WCDMA network and the CDMA network will be described with reference to  FIG. 4 . 
     FIG. 4  illustrates a packet data send/receive procedure of the DBDM (dual band dual mode) terminal in accordance with an embodiment of the present invention depicting an IP/PPP packet processing process of the video chip  10 . 
   First, when the DBDM terminal transmits data, the data is transmitted from the UI  40  to the video chip  10 . In transmitting packet data to the network  200 , the terminal processes the transmitted data as an IP frame by adding an IP header through an IP packet processing. In performing packet data transmission from the terminal to the network, the IP packet processing is performed unconditionally. 
   The video chip  10  judges a present system mode. When the present system mode is in WCDMA communication, a packet-processed IP frame is transmitted to the WCDMA modem chip  30  through an IPC driver, and the WCDMA modem chip  30  transmits the received IP frame to the WCDMA network  200 . 
   When the present system mode is in CDMA communication, the video chip  10  transmits the packet-processed IP frame to the PPP protocol, converts it into a PPP frame and transmits it to the CDMA modem  20  through the UART driver. The CDMA modem chip  20  then transmits the PPP frame to the CDMA network  200 . 
   When the DBDM terminal receives the packet data, the WCDMA modem chip  30  receives the IP frame transmitted from the WCDMA network  200  and transmits it to the video chip  10 . The video chip  10  transmits the received IP frame to the IP protocol, performs packet processing, operates a pertinent packet data service application and transmits the received data to the user interface  40 . 
   In addition, the CDMA modem chip  20  transmits the PPP packet transmitted from the CDMA network  200  to the UART driver and inputs the PPP frame to the video chip  10 . The video chip  10  transmits the received PPP frame to the PPP protocol, converts it into an IP frame, performs a packet processing through the IP protocol, operates a pertinent packet data service application and transmits the received data to the user interface  40 . 
   Because the PPP is a second layer and the IP is a third layer, the IP is a protocol superior to the PPP, and CDMA/WCDMA is constructed with IP frames. Because a PPP frame has a longer frame length and additional operation is required, the video chip  10  internally processes data to be transmitted by using IP frames and transmits IP frames to the WCDMA network promptly in comparison with performing communication by using IP frames. In the case of the CDMA network, the video chip  10  converts an IP frame into a PPP frame as a subordinate layer and transmits it. 
   Accordingly, in embodiments of the present invention, because the video chip  10  has one data communication protocol processing both IP frames and PPP frames and the modems for the communication networks, both CDMA and the WCDMA systems can be used while maintaining consistency of communication protocol. Because the application of the packet data service can be directly connected with the socket, performance of the terminal is improved. In addition, by debugging only the protocol of the video chip, development efficiency is also improved. 
   The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.