Abstract:
Disclosed are a method of controlling packet service setup and a mobile communication system. The method includes the steps of: transmitting a packet service request message containing a requested QoS to a packet service node by a mobile communication terminal; transmitting to the mobile communication terminal a packet service request response message including an assigned QoS determined in consideration of the requested QoS and network resources contained in the message received by the packet service node; comparing one or more parameter values among parameters contained in the assigned QoS contained in the packet service request response message from a mobile communication network with corresponding one or more parameter values among parameters contained in the QoS requested by the mobile communication terminal; and transmitting a packet service cancel request message if a difference between the parameter values is greater than or equal to a preset value.

Description:
BACKGROUND OF THE INVENTION 
     This application claims the priority of Korean Patent Application No. 2004-59401, filed on Jul. 28, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a mobile communication terminal and, more particularly, to a technology related to a packet service. 
     DESCRIPTION OF RELATED ART 
     Mobile communication terminals basically provide a wireless communication function using a circuit switching system. Recently, as rapid development has been made in such the mobile communication technology field, current mobile communication terminals can provide a service of a packet switching system through a general packet radio service (GPRS) network. 
     The GPRS can add voiceless information to information that is transmitted and received through a wireless communication system, and makes it possible to interconnect between a GPRS network and the existing Internet for the first time. Accordingly, the mobile communication terminal can make use of the Internet through the GPRS network, so that it can provide services such as Web browsing, chatting, E-mail, and telnet, which are currently provided via wired Internet connections. 
     When the mobile communication terminal makes use of the packet service described above, it is provided with a packet switching path for the packet service from the GPRS network. Also, the mobile communication terminal is assigned a quality of service (QoS) for using the packet switching path from the GPRS network. For reference, the QoS refers to a performance unit indicating transmission quality, transmission rate and error rate of a transmission system. 
     The mobile communication terminal can make use of a packet service, i.e., it can transmit/receive packet data, through the packet switching path provided from the GPRS network. However, when a user of the mobile communication terminal makes use of the packet service, he or she cannot identify the QoS assigned to the mobile communication terminal, particularly, a transmission speed among parameters of the QoS, even when the transmission speed does not reach a user desired level. 
     When the user determines that the transmission speed is too low due to a service delay while using the packet service, he or she may compulsorily terminate the service. For example, when the user accesses the Internet wirelessly and downloads desired content, the user may cancel the download process due to an intolerably low download speed thereof. Also, there occurs a problem in that the user is billed for the packet service regardless of the fact that the user terminated the download before completion. 
     SUMMARY OF THE INVENTION 
     The present invention provides a mobile communication terminal capable of controlling the use of packet service depending on a quality of service assigned when using the packet service. 
     In accordance with an aspect of the present invention, there is provided a method of controlling packet service setup, the method comprising the steps of: transmitting a packet service request message containing a requested QoS (quality of service) to a packet service node by a mobile communication terminal; transmitting to the mobile communication terminal a packet service request response message including an assigned QoS determined in consideration of the requested QoS and network resources contained in the message received by the packet service node; comparing one or more parameter values among parameters contained in the assigned QoS contained in the packet service request response message from a mobile communication network with corresponding one or more parameter values among parameters contained in the QoS requested by the mobile communication terminal; and transmitting a packet service cancel request message if a difference between the parameter values is greater than or equal to a preset value. 
     In accordance with another aspect of the present invention, there is provided a mobile communication system, comprising: at least one packet service node for receiving a packet service request message from a mobile communication terminal, determining an assigned QoS in consideration of a requested QoS and available network resources contained in the packet service request message, and transmitting a packet service request response message containing the assigned QoS to the mobile communication terminal; and at least one mobile communication terminal for transmitting the packet service request message to the packet service node, comparing one or more parameter values among the assigned QoS parameters contained in the packet service request response message from the packet service node with corresponding one or more parameter values among the requested QoS parameters, and transmitting a packet service cancel request message if a difference between the corresponding two QoS parameter values is greater than or equal to a preset value. 
     The packet service cancel request message may be transmitted according to a user&#39;s command if the difference between the corresponding two QoS parameter values is greater than or equal to a preset value. 
     The compared QoS parameter may be a transmission speed. 
     The transmission speed may be a downlink transmission speed. 
     The packet service node may be an SGSN. 
     The packet service request message may be a PDP Context activation request message. 
     The packet service request response message may be a PDP Context activation accept message. 
     The packet service cancel request message may be a PDP Context activation cancel message. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a schematic view showing a construction of a GPRS network serving as a packet switching network; 
         FIG. 2  is a flowchart showing a method of controlling packet service setup in accordance with a preferred embodiment of the present invention; 
         FIG. 3  is a flowchart showing a method of controlling packet service setup in accordance with another embodiment of the present invention; 
         FIG. 4  is a view showing QoS parameters; 
         FIG. 5A  is a view showing an example of a screen displayed in accordance with the method of the present invention; 
         FIG. 5B  is a view showing another example of a screen displayed in accordance with the method of the present invention; and 
         FIG. 5C  is a view showing another example of a screen displayed in accordance with the method of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Exemplary embodiments of the present invention will now be described below in more detail with reference to the accompanying drawings. Like numerals refer to like elements throughout the specification. 
       FIG. 1  is a schematic view showing a GPRS network serving as a packet switching network. The GPRS network includes two nodes, an SGSN (Serving GPRS Support Node)  40  and a GGSN (Gateway GPRS Support Node)  50 . The SGSN  40  is a node that performs position control and access control of the mobile communication terminal  10 , and transmits and receives a packet to and from a mobile communication terminal in a service area. Further, the GGSN  50  is connected to a corresponding SGSN  40  through an assigned tunnel, and serves as a gateway to another network (e.g., Internet). 
     Tunneling assignment between the corresponding SGSN  40  and GGSN  50  is performed by setting a packet data protocol context (PDP Context). The PDP Context refers to a network protocol that an external packet data network uses to communicate with the GPRS network. PDP Context setup is a preparation procedure to transmit a packet in the GPRS network, where the packet switching path is set. That is, the procedure to set a packet switching path in the GPRS network can be an operational procedure to set the PDP Context. As the PDP Context is set, a tunnel is assigned between the corresponding SGSN  40  and GGSN  50 . The set PDP Context is managed and synchronized by the mobile communication terminal  10 , the SGSN  40  and the GGSN  50 . 
     Accordingly, the mobile communication terminal  10  can perform a packet transmitting/receiving process through a packet switching path that is connected to the base station  20 , the BTS system controller  30  for controlling a plurality of base stations, the SGSN  40  and the GGSN  50 . 
       FIG. 2  is a flowchart showing a method of controlling packet service setup in accordance with an embodiment of the present invention. First, to provide the packet service to the mobile communication terminal  10 , a packet switching path setup, that is, a tunnel assignment between the SGSN  40  and the GGSN  50  which are packet service nodes should be performed (PDP Context setup) as described above. The PDP Context setup is performed using GTP-C (GTP Control plane) of the GTP (GPRS Tunnel Protocol) as described below. 
     The mobile communication terminal  10  transmits a PDP Context activation request message (Activate PDP Context Request), which is a packet service request message, to the SGSN  40  (step  100 ). The SGSN  40  receives the PDP Context activation request message transmitted from the mobile communication terminal  10  and then transmits the PDP Context setup request message (Create PDP Context Request) to the GGSN  50  in order to set up a tunnel to the GGSN  50  (step  102 ). The PDP Context setup request message includes TEID (Tunneling Endpoint Identifier) in order that the GGSN  50  may identify user traffic of the corresponding SGSN  40 . 
     The GGSN  50  receives the PDP Context setup request message from the SGSN  40  and stores the TEID of the SGSN  40 . Next, the GGSN  50  transmits a PDP Context setup response message (Create PDP Context Response) to the SGSN  40  (step  104 ). The PDP Context setup response message contains the TEID in order that the SGSN  40  may identify user traffic of the GGSN  50  and then is transmitted. The SGSN  40  receives the PDP Context setup response message and stores the TEID of the GGSN  50 . 
     When the PDP Context setup is completed through the tunnel assignment procedure as described above, it is possible to perform traffic transmitting/receiving between the SGSN  40  and the GGSN  50 . At this time, the user traffic transmitted/received between the SGSN  40  and GGSN  50  is processed according to the GTP-U (GPRS User plane) protocol, which serves as the traffic protocol. Since the user traffic processing technology according to the GTP-U protocol is well known in the art, a detailed description thereof is omitted. 
     After the PDP Context is set, the SGSN  40  transmits the PDP Context activation accept message (Activate PDP Context Accept), which is a packet service request response message, to the mobile communication terminal  10  (step  106 ). The mobile communication terminal  10  receives the PDP Context activation accept message, and checks the assigned QoS parameter among information elements contained in the PDP Context. 
       FIG. 4  is a view showing QoS parameters. The QoS includes various parameters indicating quality levels for the packet service. ‘Maximum bit rate for uplink’, ‘Maximum bit rate for downlink’, ‘Guaranteed bit rate for uplink’ and ‘Guaranteed bit rate for downlink’ are parameters related to transmission speed. 
     ‘Maximum bit rate for uplink’ and ‘Maximum bit rate for downlink’ indicate assigned maximum transmission speeds, where the ‘Maximum bit rate for uplink’ indicates the maximum bit rate for uplink transmitted within a given time, and the ‘Maximum bit rate for downlink’ indicates the maximum bit rate for downlink transmitted within a given time. In addition, ‘Guaranteed bit rate for uplink’ and ‘Guaranteed bit rate for downlink’ indicate a guaranteed transmission speed, where the ‘Guaranteed bit rate for uplink’ indicates the minimum guaranteed bit rate for uplink and ‘Guaranteed bit rate for downlink’ indicates the minimum guaranteed bit rate for downlink. 
     The mobile communication terminal compares one or more parameter values included in the assigned QoS with the parameter value stored in advance. Preferably, between the maximum transmission speed and the guaranteed transmission speed included in the assigned QoS, the mobile communication terminal compares the maximum transmission speed with a preset transmission speed (step  108 ). In accordance with an embodiment, the mobile communication terminal  10  compares the ‘Maximum bit rate for uplink’ or ‘Maximum bit rate for downlink’ with preset uplink transmission speed or downlink transmission speed. In accordance with another embodiment, the mobile communication terminal  10  can compare both of ‘Maximum bit rate for uplink’ and ‘Maximum bit rate for downlink’ with the preset uplink transmission speed and downlink transmission speed. 
     If the transmission speed included in the QoS, i.e., the assigned transmission speed, is lower than the preset transmission speed as a result of the comparison, the mobile communication terminal transmits a PDP Context activation cancel message (that is, deactivation request message), which is a packet service cancel request message, to the SGSN  40  (step  114 ). For example, if the preset transmission speed in the mobile communication terminal  10  is 32 Kbps and the assigned transmission speed is 16 Kbps, the mobile communication terminal  10  transmits the PDP Context activation cancel message to the SGSN  40 . The SGSN  40  performs a procedure for the assigned tunnel cancel process with the GGSN  50 . Such a procedure is well known in the art, and a detailed description thereof is thus omitted. 
     Preferably, when the assigned transmission speed is lower than the preset transmission speed, the mobile communication terminal  10  displays packet service release information on, for example, a liquid crystal display (LCD), and informs the user of this fact before transmitting the PDP Context activation cancel message to the SGSN  40 .  FIG. 5A  is a view showing an example of service release information displayed on the LCD of the mobile communication terminal. As shown in  FIG. 5A , when the mobile communication terminal  10  automatically terminates the packet service due to the fact that the assigned transmission speed is lower than the preset speed, it displays a pop-up window on the LCD for 1 or 2 seconds. Next, the mobile communication terminal  10  transmits the PDP Context activation cancel message to the SGSN  40  and releases the packet service. 
     Accordingly, since the mobile communication terminal automatically performs the packet service use release in the case where the transmission speed assigned when using the packet service is lower than the preset transmission speed, the problems of user inconvenience and additional costs levied against the user, which occur when the user uses the packet service at a low transmission speed, can be solved. 
     In step  108 , if the assigned transmission speed is greater than or equal to the preset transmission speed, the mobile communication terminal  10  is connected to the Internet network through the set packet switching path to process traffic transmission/reception (step  110 ). Accordingly, the mobile communication terminal can gain access to the Internet and then download desired content and the like. 
     If there is a command for packet service termination according to a user&#39;s key operation (step  112 ), the mobile communication terminal  10  transmits a PDP Context activation cancel message to the SGSN  40  as in step  114 . Without the command, the mobile communication terminal  10  continues to process the traffic transmitting/receiving process as in step  110 . 
     According to another feature of the present invention, the mobile communication terminal  10  transmits the PDP Context activation cancel message to the SGSN  40  according to a user&#39;s command in the case where the transmission speed included in the assigned QoS is lower than the preset transmission speed. 
     In the step  108 , if the transmission speed included in the QoS, that is, the assigned transmission speed is lower than the preset transmission speed, the mobile communication terminal  10  preferably informs the user of this fact through the LCD as shown in  FIG. 5B . The user identifies that the assigned transmission speed is lower than the preset transmission speed through the LCD, and determines whether or not the packet service use is released. If the user selects ‘YES’ through the key operation, the mobile communication terminal releases the packet service by transmitting the PDP Context activation cancel message to the SGSN  40  as in step  114 . 
     However, if the user selects ‘NO’ through the key operation, the mobile communication terminal  10  does not transmit the PDP Context activation cancel message to the SGSN  40  even though the assigned transmission speed is lower than the preset transmission speed. This is because the user may need to use the packet service even though the assigned transmission speed is lower than the preset transmission speed. Accordingly, the mobile communication terminal  10  can be connected to the Internet network to transmit the traffic as in step  110 . 
     According to another feature of the present invention, the transmission speed described above is a transmission speed for the downlink. Generally, since a user of the mobile communication terminal makes use of the packet service to download various content such as a game, the transmission speed for the downlink is a critical factor to the user. Accordingly, the mobile communication terminal  10  compares the assigned downlink transmission speed, that is, ‘Maximum bit rate for downlink’ with the preset transmission speed, and controls packet service setup. 
       FIG. 3  is a flowchart showing a method of controlling packet service setup in accordance with another embodiment of the present invention. Hereinafter, in describing the present invention with reference to  FIG. 3 , a description already mentioned in  FIG. 2  is omitted. If the mobile communication terminal  10  receives the PDP Context activation accept message from the SGSN  40  in step  106 , it displays the transmission speed included in the QoS parameter among PDP Context information elements (see  FIG. 4 ), i.e., the assigned transmission speed, on the LCD. 
       FIG. 5C  is a view showing an example where a transmission speed assigned by the mobile communication terminal  10  for the packet service use is displayed on the LCD. After the user of the mobile communication terminal identifies the transmission speed assigned for the packet service use, he or she determines whether or not to use the packet service and selects ‘YES’ or ‘NO’. 
     If the user selects ‘NO’, that is, the user commands the packet service to be terminated, the mobile communication terminal  10  transmits the PDP Context activation cancel (deactivation request) message to the SGSN  40  as in step  114 , thereby releasing the packet service. If the user commands the packet service to be used by selecting ‘YES’, the mobile communication terminal  10  can be connected to the Internet network and perform the traffic transmitting/receiving process as in step  110 . 
     The mobile communication system based on the SGSN and the mobile communication terminal controls the packet service setup through signal processing. The mobile communication system can be described in the same manner with reference to  FIGS. 1 and 2  as described above, and a detailed description thereof will thus omitted. 
     As described above, since the mobile communication terminal in accordance with the present invention determines whether or not to use the packet service depending on the transmission speed assigned when using the packet service, it is possible to solve problems of user inconvenience and additional costs levied against the user, which may occur when the user uses the packet service at a low transmission speed. 
     While the present invention has been described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the present invention as defined by the following claims.