Patent Application
20080192681
The present invention relates to multi-mode user equipment and a method for controlling a communication path of multi-mode user equipment. More particularly, the present invention relates to multi-mode user equipment for supporting access to a plurality of networks, and a method for controlling a communication path for enabling data communication through an optimal network.
Recently, as user's interest and demand for use of the mobile Internet has increased, wireless data communication that provides bi-directional communication anytime and anywhere using a communication terminal such as a portable terminal, a notebook computer, and a personal digital assistant (PDA) rather than using an existing data communication service served through a wired network has emerged.
As wireless communication networks are being continuously developed, wireless data communication services are provided on the basis of new types of wireless networks, such as a code division multiple access (CDMA) scheme, and a wideband CDMA (WCDMA) that has been developed in an asynchronous manner is also provided for serving the wireless data communication service.
In addition, the existing wireless local area network (WLAN) system such as the IEEE 802.11 standard can be variously applied for establishing a network between buildings, an area where mobility of a terminal is essential, or an area where it is difficult to install cables. The WLAN provides a data communication scheme that allows short-range wireless communication with reference to stationary access points, and thus the WLAN supports wireless data communication as opposed to wired data communication in a local area rather than supporting mobility of a mobile subscriber station (MSS).
A wireless broadband portable Internet service (WiBro) system is being developed at present by combining features of the WLAN that provides a data communication service with high speed and high quality and a mobile communication network having a wide range of service available areas in order to support the mobility of the MSS.
The WiBro, developed by the IEEE 802.16 working group, guarantees mobility at 60 km/h within 1 km using the 2.3 GHz band frequency, and supports a 3 Mbps download speed and a 1 Mbps upload speed for each subscriber. The WiBro system has merits of mobility and high-speed data communication, but it also has drawbacks in that its service coverage is relatively small and a mobile communication system cannot be provided with high-speed service due to limited capacity.
Coverage areas of various communication networks may be overlapped, and therefore it is important to achieve stable data communication in accordance with traffic conditions of the respective networks when a subscriber's terminal is located in the overlapped coverage area. However, according to the prior art, a mobile terminal supporting service that is available only in the respective networks is used and accordingly it has been difficult to provide a data communication service through an optimal network in an area where the mobile terminal is located.
In addition, a handover is performed from a network-centric point of view even though various network services can be supported by one mobile terminal, and therefore there has been a problem of providing optimal network services since traffic conditions of the corresponding network, characteristics of the mobile terminal, and characteristics of data packets that the mobile terminal transmits/receives at a specific point are not taken into account according to the prior art.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
It is an advantage of the present invention to provide multi-mode user equipment that is capable of selecting an optimal network in overlapped coverage areas of various networks, and a method for controlling a communication path for the multi-mode equipment.
In one aspect of the present invention, multi-mode user equipment for supporting wireless data communication with the Internet via a plurality of access networks includes an interface unit and a user equipment operating unit. The interface unit includes a plurality of network interfaces for supporting access to the respective access networks. The user equipment operating unit receives information on the state of the respectively corresponding access networks from the plurality of network interfaces, selects an access network that is capable of providing stable data communication from among the plurality of access networks based on the information, and establishes a data communication path. In addition, the multi-mode user equipment and the respective network interfaces are allocated IP addresses, and the user equipment operating unit includes a network module that matches and manages information on the state of the plurality of access networks transmitted from the plurality of network interfaces and information on the IP addresses allocated to the respective network interfaces.
In another aspect of the present invention, there is provided a method for controlling a data communication path for multi-mode user equipment that includes a plurality of network interfaces respectively supporting access to a plurality of access networks and supports wireless data communication with the Internet via the plurality of access networks. In the method, the multi-mode user equipment obtains IP addresses for the plurality of network interfaces and the multi-mode user equipment, and collects information on the state of access networks that are respectively accessible through the plurality of network interfaces.
In addition, the multi-mode user equipment generates an interface state table by matching the collected information and the IP addresses allocated to the plurality of network interfaces, and generates a path information table by selecting a network interface that supports access to an access network providing stable data communication based on the interface state table. The path information table includes information on a destination IP address for data packet transmission, information on an IP address allocated to the network interface selected by the multi-mode user equipment, and information on an identifier of a timer that controls a lifetime of a data communication path established between the destination IP address and the IP address allocated to the selected network interface.
According to the present invention, an optimal access network for data packet transmission can be selected by multi-mode user equipment and a data transmission path can be controlled without changing upper layers, thereby guaranteeing mobility in an IP-based communication environment.
In addition, the optimal access network for data packet transmission can be selected in accordance with the type of application service provided to a user in overlapped coverage areas of various networks, and accordingly, the IP-based data communication service can be synchronously achieved through a plurality of networks.
Further, the multi-mode user equipment can easily access various access networks using various network interfaces.
An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.
In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.
Accordingly, the drawings and description are to be regarded as illustrative in nature, and not restrictive. Like reference numerals designate like elements throughout the specification. In addition, throughout the specification and claims that follow, unless explicitly described to the contrary, the word “comprise/include” or variations such as “comprises/includes” or “comprising/including” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.
In addition, the word “module” means “a block configured to enable modification of a system of a hardware or software, or provide a plug-in function thereto, that is, a unit or block that performs a specific function of hardware or software.
Through the specification and claims, the word “multi-mode user equipment” refers to a communication terminal that is capable of IP-based data communication, and the multi-mode user equipment includes a notebook computer and a personal digital assistant (PDA), and is not restrictive.
Multi-mode user equipment and a method for controlling a communication path of the multi-mode user equipment according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in
At this time, the multi-mode UEs 212 to 214 located in the overlapped coverage areas of different networks respectively perform an algorithm for selecting an optimal network for data communication on the basis of the strength of network signals and traffic signals, traffic conditions, and information on network types that can be supported by each UE 212 to 214 in order to achieve the data communication service through a selected network.
In other words, the multi-mode UE 100 supports an interactive interface between the Internet 1000 and the various access networks 10 to 30 in order to allow a subscriber to use an IP packet-based data communication service of the Internet 1000 via the various access networks 10 to 30 by using the multi-mode UE 100 according to the exemplary embodiment of the present invention. In addition, when the network traffic conditions have changed due to movement of the corresponding subscriber or an increase in the number of other subscribers who access the same network, the multi-mode UE 100 may perform data transmission path routing to guarantee optimal wireless communication quality.
Unlike a conventional network-based path control algorithm, a path control algorithm according to the embodiment of the present invention is based on the multi-mode UE 100. The multi-mode UE 100 continuously checks a communication environment of an accessible network and controls a data packet transmission path, and thereby consistently and appropriately responds to variations of the communication environment. In addition, a plurality of data transmission paths via the access networks 10 to 30 can be established to be appropriate for data packets that are respectively generated in accordance with types of application programs executed in the multi-mode UE 100.
As shown in
The UE operating unit 300 reads a packet's address by analyzing a header of the data packet, determines an appropriate path, and controls data packet flow and transmission of data packets generated from an application program, and the interface unit 200 transmits/receives the data packets through physical access to the plurality of access networks 10 to 30.
The interface unit 200 realizes functions of a data link layer and a physical layer, and the UE operating unit 300 realizes functions of upper layers of the data link layer, i.e., a network layer, a transport layer, and an application layer. Some of the functions realized in the upper layers may be shared by the interface unit 200 and the UE operating unit 300 depending on characteristics of the network interfaces 210 to 230.
The interface unit 200 includes a plurality of network interfaces 210 to 230 respectively supporting the plurality of access networks 10 to 30 so as to allow the multi-mode UE 100 to function as a UE that is appropriate for the corresponding Internet. As described, the plurality of network interfaces 210 to 230 of the interface unit 200 are configured to realize the functions of the data link layer and the physical layer.
For example, the first network interface 210 may be configured to realize functions of the physical layer and the data link layer that support access to a wireless local area network (WLAN). The second network interface 220 may be configured to realize functions of the data link layer and the physical layer that support access to a code division multiplexing access (CDMA)-based mobile communication network. In addition, the third network interface 230 may be configured to realize functions of the data link layer and the physical layer that support access to a 3GE network and session and bearer establishment.
The third network interface 230 is configured to include a radio resource control (RRC) layer, a radio link control (RLC) layer, a logical link control (LLC) layer, and a media access control (MAC) layer, and realizes mobility management, session establishment, and bearer establishment by signaling between a serving GPRS support network and a gate GPRS supporting node in the 3GE network. In addition, the plurality of network interfaces 210 to 230 are respectively assigned IP addresses for operation.
A hardware module type of network interface, such as a universal serial bus (USB), an IEEE 1394, and PCMCIA, etc., can be used as a network interface for the multi-mode UE 100, or the network interface can be provided in a software module having the above-stated protocol stack and installed to the multi-mode UE 100 according to the embodiment of the present invention.
As shown in
The access module 310 includes a plurality of device drivers 311 to 313 respectively corresponding to the plurality of network interfaces 210 to 230 in the interface unit 200 for controlling the interface unit 200 and supporting the operating system of the multi-mode UE 100. As a constituent element for connecting the multi-mode UE 100 and the respective network interfaces 210 to 230, the access module 310 controls hardware constituent elements to appropriately perform expected functions for the corresponding operating system.
That is, the access module 310 controls the respective network interfaces 210 to 230 to establish data communication, and controls the multi-mode UE 100 to function as a UE that is appropriate for characteristics of the corresponding network when the data communication is established through a network interface selected by the multi-mode UE 100.
The network module 320 supports an Internet protocol, and includes a network selection algorithm for selecting a network that can provide optimal wireless data communication quality from among a plurality of access networks than can be supported by the multi-mode UE 100. In addition, the network module 320 collects and manages information on the state of the plurality of access networks, and controls establishment and release of the data communication path through the access network that has been selected on the basis of the information.
The network module 320 controls a data packet transmission path between the multi-mode UE 100, the access networks 10 to 30, and the Internet 1000 within the overlapped coverage area of the plurality of access networks by repeatedly performing the network selection algorithm. In addition, the network module 320 intercepts externally transmitted data packets and externally received data packets, and analyzes IP packet headers of the intercepted packets.
The network module 320 periodically checks variations of the received electric field strength in the respective access networks 10 to 30 by exchanging signals with the respective interfaces 210 to 230 of the interface unit 200, and generates an interface state table 600 for recording information on communication states of the respective access networks 10 to 30. In addition, the interface state table 600 is updated in accordance with variations of the communication state.
The network module 320 selects a network interface, that is, an access network, from among the network interfaces 210 to 230 for providing optimal communication quality on the basis of information recorded in the interface state table 600. In addition, the network module 320 manages information on IP addresses allocated to the network interfaces 210 to 230 for supporting physical access to the access network selected as a result of the network selection algorithm process and information on time set for data transmission through the corresponding path as a form of a path information table 700.
The network selection algorithm used by the multi-mode UE 100 in the embodiment of the present invention is well known, and accordingly, an appropriate network selection algorithm may be selected for the corresponding communication algorithm by those skilled in the art. The network selection and data transmission path control will now be described in more detail.
The transmission module 330 supports a transmission control protocol and a user datagram protocol, and defines data transmission, error correction, and flow control for establishing reliable data communication.
The application service module 340 supports an application program designed to perform a specific service. The application program may include an IP-based packet service application program that is designed to perform web browsing, file transmission, and a streaming service client role. For example, the application service module 340 may include an MP3 codec, an H.263 codec, a web browser, a media player, and an image communication program, etc. The application service module 340 generates a data packet according to a user's application program and transmits the data packet to the Internet 1000.
With such a configuration, the plurality of network interfaces 210 to 230 in the UE operating unit 300 and the interface unit 200 of the multi-mode UE 100 may be respectively assigned an IP address for operation according to the embodiment of the present invention. Allocation of the IP addresses is consistent with an IP allocation method that is appropriate for an operating system environment selected by the multi-mode UE 100. In addition, the multi-mode UE 100 sets one of the IP addresses as a default IP address and uses the default IP address as an identifier of the multi-mode UE 100 in the plurality of access networks 10 to 30.
The plurality of network interfaces 210 to 230 of the interface unit 200 include a physical layer that allows the multi-mode UE 100 to physically access the corresponding network or maintains the physical access between the multi-mode UE 100, and defines electrical, mechanical, procedural, and functional specifications and a data link layer for providing reliable data transmission through the physical access. The network interfaces 210 to 230 including such a protocol stack structure may be configured to have various detailed layers in accordance with types of accessible networks.
For example, the first network interface 210 for supporting access to the WLAN may include the physical layer and the data link layer. In addition, the third network interface 230 for supporting access to the 3GE network may have a protocol stack structure in addition to the physical layer and the data link layer. The protocol stack structure includes a protocol, e.g., a GPRS Mobility Management and Session Management (GMM/SM) protocol partially sharing functions of a network layer performing a function for establishing a session and bearer.
As described, configuration of the multi-mode UE 100 can be varied as long as the network work interfaces 210 to 230 support protocols of the physical layer and the data link layer, the UE operation unit 300 supports protocols of layers higher than the physical and data link layers, and the network interfaces 210 to 230 partially share the functions of the upper layers. A protocol stack and a user application program of the UE operating unit 300 which is interactively operated with the interface unit 200 are determined in accordance with such a configuration of the protocol stack of the network interfaces 210 to 230.
A method for selecting a network and controlling a path performed by the multi-mode UE 100 according to an exemplary embodiment of the present invention will now be described.
When the multi-mode UE 100 is supplied with power, the multi-mode UE 100 starts receiving a transmission signal with the network where the multi-mode UE 100 is located after an operating system of the multi-mode UE 100 is initialized, an initial network environment is set, and communication protocol parameters are initialized, in step S510.
The multi-mode UE 100 is assigned an IP address for the respective network interfaces 210 to 230 in the interface unit 200 in step S520. In addition, the multi-mode UE 100 may be assigned an additional IP address for the UE operating unit 300.
At this time, a subscriber may obtain a static IP address for the multi-mode UE 100, and the user may also obtain an IP address through a dynamic host configuration protocol (DHCP) provided by a WLAN access point during initialization of the WLAN in the case that the network interfaces 210 to 230 support access to the WLAN network. In addition, in the case that the network interfaces 210 to 230 support access to the CDMA or 3GE network, the subscriber may obtain an IP address through a signaling process for session and bearer establishment.
The multi-mode UE 100 may set the static IP address among the plurality of IP allocated addresses as a default IP address, or set an initially allocated IP address among IP addresses allocated to the network interfaces 210 to 230 as the default IP address. The default IP address is used as an identifier of the corresponding multi-mode UE for data communication. At this time, the multi-mode UE 100 stores information on the state of the respective access networks transmitted from the interface unit 200 and the plurality of IP addresses in the form of the interface state table 600 and the path information table 700.
The network module of the multi-mode UE 100 performs the network selection algorithm on the basis of the information stored in the interface state table 600 and selects a network for optimal data communication in step S530. Service lifetime and service price of the multi-mode UE 100 may be used as reference parameters when performing the network selection algorithm for selecting the optimal network.
In terms of data transmission power for a mobile UE that typically uses a battery as a power source, a power consumption amount can be varied depending on an overhead of a link layer protocol. Therefore, the multi-mode UE 100 can select a network that is capable of minimizing battery power consumption among currently accessible networks. In addition, a rate system for transmitting/receiving one packet may differ in accordance with types of the access networks 10 to 30, and a user of the multi-mode UE 100 prefers to use a network with an inexpensive rate system, and therefore the service price becomes an important parameter.
In addition, after a network is selected on the basis of the above-stated parameters, consistent quality of service (QoS) should be guaranteed between different access networks when the type of access network through which data communication is performed between the multi-mode UE 100 and the Internet 1000 is changed. Therefore, the network module 100 modifies various protocol parameters including communication speed and QoS management policy for the selected network.
When the network selection algorithm is performed and a network for providing an optimal data communication service is selected at a present location of the multi-mode UE 100, the path information table 700 is updated in step S540.
Steps S520 and S540 of
The network interface field 610 records and manages IP addresses allocated to the network interfaces 210 to 230 in the multi-mode UE 100. IP addresses allocated to the respective network interfaces 210 to 230 during the initialization stage of the multi-mode UE 100 are recorded. In addition, the network interfaces 210 to 230 may obtain new IP addresses when the multi-mode UE 100 moves and re-enters the previous access network, and the network interface field 610 may be updated. During the initialization stage of the multi-mode UE 100, each network interface field 610 has a null value.
The use state field 620 records and manages the possibility of use of the plurality of interface networks 210 to 230 in the multi-mode UE 100. That is, when the plurality of network interfaces 210 to 230 are activated and allocated IP addresses such that they are in the state of being able to provide a data communication service, the use state field 620 is recoded with a value indicating that the plurality of interface networks 210 to 230 can be used. In addition, when the multi-mode UE 100 moves out of a coverage area of a single network, when the multi-mode UE 100 enters the coverage area but a network card for accessing the corresponding network is not provided to the multi-mode UE 100, or when a deactivated network card is provided to the multi-mode UE 100, the use state field 620 is recorded with a value indicating that the plurality of interface networks 210 to 230 cannot be used and functions to inform that data communication cannot be achieved through the corresponding access network.
In addition, a user of the multi-mode UE 100 may directly determine whether to activate or deactivate the network interfaces 210 to 230 through a setting of the multi-mode UE 100. A value of the use state field 620 is set to be null when the network interfaces 210 to 230 are in the deactivation state. Network interface selection of the network module 320 for the network selection algorithm is limited to network interfaces that are in a usable state in the use state field 620.
The signal stability field 630 measures the strength of signaling signals and traffic signals between the network interfaces 210 to 230 and the corresponding access networks 10 to 30, which have been collected from the interface unit 200 by the multi-mode UE 100, and records and manages a signal stability level obtained by quantifying the measured strength. The network module 320 stores a signal stability level for a network interface in the usable state on the basis of the information recorded in the use state field 620.
At this time, the network module 320 measures the strength of the signaling signals when the multi-mode UE 100 receives a “hello” message periodically broadcasted from the corresponding access network or receives a response to a “probe” message that has been transmitted to the access network from the multi-mode UE 100.
In addition, the signal stability level is calculated by using the measured strength of the signaling and traffic signals. Information on a threshold value of the signal stability, which has been predetermined in accordance with the type of application program used by the subscriber and characteristics of traffic signals, may be embedded in the network module 320 of the multi-mode UE 100, and thus the multi-mode UE 100 may select an appropriate network for data communication based on the information.
A method for analyzing signal stability used for the multi-mode UE 100 is well-known to those skilled in the art, and the method used for the multi-mode UE 100 according to the exemplary embodiment of the present invention may be selected to be appropriate for an operation system and network conditions.
The destination IP address field 710 records and manages a destination IP address to which the generated data packets are expected to be transmitted. The destination IP address may be added or modified by performing the network selection algorithm in the network module 320.
The network interface field 730 records and manages IP addresses allocated to network interfaces for supporting the multi-mode UE 100 to directly access an access network selected as a result of performing the network selection algorithm. The IP address stored in the network interface field 730, that is, the IP address allocated to a specific network interface, may be added or modified by performing the network selection algorithm in the network module 320.
The timer field 720 records and manages a timer identifier that manages time available for communication through a data transmission path, that is, the lifetime of the data transmission path established by using the IP address recorded in the IP address field 710 as a destination and the IP address recorded in the network interface field 730 as a source.
When a network interface is selected from among the plurality of network interfaces 210 to 230 by performing the network selection algorithm, the multi-mode UE 100 generates a timer for setting the lifetime of a data transmission path using the selected network interface, assigns an identifier to the timer, and records the identifier to the timer field 720. At this time, the lifetime set by the timer may vary depending on movement speed of the multi-mode UE 100 and characteristics of the application program generating the data packet.
Similar to the network interface field 730, the timer field 720 is also updated when the network selection algorithm of the network module 320 is performed. In addition, a timer corresponding to the identifier recorded in the timer field 720 is reset when there is a data packet to be transmitted through the data transmission path, and the time is timed-out when there is no data packet subsequently transmitted through the data transmission path within a predetermined time period, and the data transmission path is released. When the timer is timed-out, the corresponding data transmission path is removed from the network transmission table 700.
As described, the lifetime of the corresponding data transmission path is set by using the timer in order to prevent resources of the multi-mode UE 100 from being wasted by maintaining a data transmission path which is no longer used for transmitting a data packet since the multi-mode UE 100 directly selects an access network, and thus a service termination point is not provided.
With such a configuration, the multi-mode UE 100 according to the exemplary embodiment of the present invention enables one multi-mode UE to perform data communication through various data transmission paths in accordance with characteristics of data packets to be transmitted and traffic of an access network to be used.
When a data packet to be transmitted to the Internet 1000 is generated by executing an application program of a subscriber's multi-mode UE 100, upon a service request, the network module 320 intercepts the data packet of the multi-mode UE 100 and analyzes a header of the data packet in step S810. The multi-mode UE 100 extracts a source IP address and a destination IP address of the data packet by analyzing the packet header.
The multi-mode UE 100 determines whether information on a data transmission path using the corresponding destination IP address is recorded in the path information path 700 on the basis of the extracted destination IP address in step S820.
When the destination IP address of the data packet is recorded in the path information table 700, the source IP address of the data packet is changed to an IP address of a network interface recorded in the network interface field 730 of the path information table 700 in step S821. The changed source IP address represents the next path through which the data packet is transmitted, that is, the changed source IP address represents an optimal destined access network.
When the destination IP address of the data packet is not recorded in the path information table 700, the multi-mode UE 100 temporarily stores the corresponding data packet in a queue of the UE operating unit 300 in step S830.
In addition, the multi-mode UE 100 selects the most stable access network with reference to the use state field 620 and the signal stability field 630 of the interface state table 600 in step S840. At this time, the multi-mode UE 100 may select a network interface with the highest signal stability level in the signal stability field 630 from among activated network interfaces, but the multi-mode UE 100 may also select an appropriate access network based on resources and other parameters of the network selection algorithm of the multi-mode UE 100.
The multi-mode UE 100 determines whether the selected network interface supports a protocol that provides the session and bearer establishment function. When the selected network interface supports the protocol, the multi-mode UE 100 interacts with the corresponding access network for the session and bearer establishment using the session and bearer establishment protocol supported by the interface unit 200 in step S850. When the selected network interface does not support the protocol, the multi-mode UE 100 interacts with the corresponding access network for the session and bearer establishment using the session and bearer establishment protocol supported by the UE operating unit 300.
When the session and bearer establishment process performed through the interaction between the interface unit 200 or UE operating unit 300 and the selected access network is terminated, an IP address allocated to the corresponding network interface and the destination IP address extracted from the data packet are correspondingly recorded in the path information table 700 such that the path information table 700 is updated in step S860. At this time, the multi-mode UE 100 generates a timer for controlling lifetime of the corresponding data transmission path, assigns an identifier to the timer, and records the identifier to the timer field 720 of the path information table 700.
When an optimal data transmission path for the data communication service is established through the above-stated process, the data packet temporarily stored in the queue is pulled out and a source IP address of the data packet is changed to the IP address allocated to the selected network interface in step S870. The IP address allocated to the selected network interface indicates an access network destination of the data packet, and therefore the multi-mode UE 100 according to the exemplary embodiment of the present invention may perform data communication via an optimal network access by managing the path information table 700.
The multi-mode UE 100 transmits the data packet, of which the IP address has been changed, to a destination of the Internet 1000 through the selected access network in step S880. At this time, a timer corresponding to the identifier recorded in the path information table 700 is reset when the data packet is transmitted, and the timer is timed-out when there is no data packet subsequently transmitted through the data transmission path within a predetermined time period. In addition, the data transmission path is released and removed from the path information table 700, and the service session and bearer are released.
Through such a process, resources and power of the multi-mode UE 100 can be efficiently used by blocking signaling with the corresponding transmission path when data transmission to a specific destination IP address is stopped due to termination of the corresponding application program.
In addition, when the multi-mode 100 is located in overlapped coverage areas of different networks and a data transmission path selected by the network selection algorithm of the network module 320 is recorded in the path information table 700, packet transmission is available through various paths at a specific point until before data packet transmission is stopped and the timer is timed-out. Therefore, the subscriber of the multi-mode UE 100 may use various application programs with optimal service quality.
When a data packet is externally received at the multi-mode UE 100 through one network interface, the network module 320 of the multi-mode UE 100 analyzes a header of the data packet and extracts a destination IP address and a source IP address in steps S910 and S920.
The multi-mode UE 100 searches the path information table 700 in the network module 320 based on the extracted destination and source IP addresses in step S930. That is, multi-mode UE 100 determines whether the network interface field 730 and the destination IP address field 710 have corresponding information by searching the network interface field 730 by using the destination IP address of the packet and searching the destination IP address field 710 of the path information table 700.
When a transmission path for transmitting the received data packet is recorded in the path information table 700, a timer assigned to the path is reset and updated in step S940.
The multi-mode UE 100 changes the destination IP address of the received data packet to a default IP address of the multi-mode UE 100, that is, an IP address allocated to the UE operating unit 300, in step S950.
In addition, the multi-mode UE 100 transmits the data packet having the changed header information to an upper entity that supports a transmission protocol in order to allow provision of a user-desired data communication service in step S960. At this time, the multi-mode UE 100 sets the corresponding timer that controls the lifetime of the corresponding path to time-out, releases the session and bearer, and removes the corresponding field from the path information table 700 when the multi-mode UE 100 perceives that no more data packets are externally transmitted when there are no data packets subsequently transmitted within the predetermined time period.
The timer controlling the lifetime of the data transmission path established by the network selection algorithm is reset when there is a data packet to be transmitted according to the exemplary embodiment of the present invention. However, the setting of the timer may be canceled and a new timer may be generated, and thus an identifier of the new timer is recorded in the path information table 700 for controlling the data transmission path.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2005-0042436 | May 2005 | KR | national |
| 10-2005-0108947 | Nov 2005 | KR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/KR2006/001886 | 5/19/2006 | WO | 00 | 11/20/2007 |
