KR102058991B1 - Dual mode terminal and controlling method therefor - Google Patents

Abstract

In a dual mode terminal capable of connecting to a plurality of networks, a period in which a connection is made to a network that is more advanced than the network while being connected to any one network, and attempts to connect according to a change in a wireless communication environment. To change. As a result, unnecessary connection attempts are minimized, thereby minimizing inconvenience such as waste of power, discontinuity of data transmission and reception, and loss of information due to discontinuity of data transmission.

Description

Dual mode terminal and control method therefor {DUAL MODE TERMINAL AND CONTROLLING METHOD THEREFOR}

The present invention relates to a dual mode terminal and a control method therefor. More specifically, the present invention relates to a dual mode terminal having an adaptive connection cycle according to a wireless communication environment when attempting to connect to a senior network in a state of being connected to a secondary network and a control method thereof.

In the field of wireless mobile communication, there has been a steady evolution in terms of not only voice calls but also high-speed data transmission and reception. At present, the fourth generation mobile communication technology, for example, LTE (Long Term Evolution) wireless communication system, is drawing attention. However, in the situation where the 4G communication network and the 3G communication network commercially available are mixed, the mobile communication terminal or the mobile communication data card is not only the 4G mobile communication technology but also the 3G mobile communication technology that is commercially available and widely used now. Must be included at the same time. Therefore, in order to simultaneously support the next generation of mobile communication technology and the previous generation of mobile communication technology, a mobile terminal having a dual modem processor or a data card type device (hereinafter, dual mode terminal) is required.

Dual-mode terminals are equipped with two modems with different communication methods to support wireless communication using each, and are mainly used in areas where heterogeneous communication networks are mixed. As a representative example of a dual mode terminal, a device capable of using both LTE (Long Term Evolution) wireless communication and CDMA (Code Divisional Multiple Access) wireless communication has attracted attention. In the present invention, for example, but described as a dual-mode terminal that can communicate with both LTE network, CDMA network, it is obvious to those of ordinary skill in the art that other methods of wireless communication can also be applied. One is true.

The LTE network is an advanced network than the CMDA network. In the dual mode terminal, the LTE network is used as the advanced network, and the CDMA network is used as the subordinate network. Therefore, even if the LTE network and the CDMA network is mixed in the region, even if the CMDA network is connected to the LTE network continues to attempt to connect.

However, when attempting to connect to the LTE network is accompanied with problems such as waste of power and discontinuity of data transmission and reception, there is a demand for a method that can minimize unnecessary attempts.

Based on the above discussion, the following will propose a dual mode terminal and a control method for minimizing an attempt to connect to a senior network while connected to a subordinate network.

The dual mode terminal of the present invention for solving the above problems is a first wireless communication module for communicating with a first communication network, a second wireless communication module for communicating with the second communication network, and received from the first communication network And a processor for processing one signal and a signal received from the second communication network, wherein the processor periodically attempts to connect to the second communication network while connected to the first communication network, When the communication environment information indicating the communication state is the same as the previous connection attempt, a dual mode terminal for increasing the connection period is provided.

In addition, the control method of the dual-mode terminal of the present invention for solving the above problems is the step of controlling the first wireless communication module to communicate with the first communication network, and periodically connected to the first communication network And attempting to connect to the second communication network, wherein the attempting step includes: dual mode for increasing an access period when communication environment information indicating a wireless communication state of the second communication network is the same as the previous connection attempt. Provided is a control method of a terminal.

According to an embodiment of the present invention, the dual mode terminal can minimize unnecessary connection attempts, thereby minimizing problems such as data loss due to discontinuity of data transmission and reception. In addition, there is an advantage that it is possible to prevent unnecessary waste of power required for the connection attempt.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

1 is a diagram conceptually illustrating a network structure of an E-UMTS.
2 is a diagram conceptually illustrating a network structure of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN).
3 and 4 illustrate a control plane and a user plane (U-Plane, User-Plane) structure of a radio interface protocol between a terminal and an E-UTRAN based on the 3GPP radio access network standard. It is a figure shown.
5 is a diagram showing the structure of a dual-mode terminal of the present invention.
FIG. 6 is a flowchart illustrating a method for repeatedly connecting to an LTE network while connected to a CDMA network by a general method.
7 is a flowchart illustrating a method for repeatedly connecting to an LTE network while connected to a CDMA network according to an embodiment of the present invention.
8 illustrates a block diagram of a terminal device according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details. For example, the following detailed description will be described in detail assuming that the main mobile communication system is a 3GPP LTE system, but is applicable to any other mobile communication system except for the specific matters of 3GPP LTE.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

In addition, in the following description, it is assumed that a terminal collectively refers to a mobile or fixed user terminal device such as a user equipment (UE), a mobile station (MS), and the like. In addition, it is assumed that the base station collectively refers to any node of the network side that communicates with the terminal, such as Node B, eNode B, Base Station.

Prior to describing the present invention, the following describes the Evolved Universal Mobile Telecommunications System (E-UMTS) and technical features related thereto.

1 is a diagram conceptually illustrating a network structure of an E-UMTS. In particular, the E-UMTS system has evolved from the existing WCDMA UMTS system and is currently undergoing basic standardization work in the 3rd Generation Partnership Project (3GPP). E-UMTS is also called a Long Term Evolution (LTE) system. For details of technical specifications of UMTS and E-UMTS, refer to Release 7 and Release 8 of the "3rd Generation Partnership Project; Technical Specification Group Radio Access Network", respectively.

Referring to FIG. 1, an E-UMTS is mainly an Access Gateway (hereinafter referred to as an AG) connected to an external network by being located at an end of a user equipment (UE), a cell (eNB), and a network (E-UTRAN). It is composed. Typically, an eNB may transmit multiple data streams simultaneously for broadcast service, multicast service and / or unicast service. An interface for transmitting user traffic or control traffic may be used between eNBs.

The AG may be divided into a part that handles user traffic and a part that handles control traffic. In this case, a new interface may be used to communicate with each other between the AG for processing new user traffic and the AG for controlling traffic. In addition, the AG manages mobility of the UE in units of a tracking area (TA), and the TA is configured of a plurality of cells. When the UE moves from one TA to another TA, it notifies the AG that the TA where it is located has changed.

CN (Core Network) may be configured as a network node for user registration of the AG and the UE. An interface for distinguishing between E-UTRAN and CN may be used.

2 is a diagram conceptually illustrating a network structure of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN).

Referring to FIG. 2, the E-UTRAN system is an evolved system from the existing UTRAN system. The E-UTRAN consists of cells (eNBs), which cells are connected via an X2 interface. The cell is connected to the terminal through the air interface, and is connected to the Evolved Packet Core (EPC) through the S1 interface.

The EPC includes a mobility management entity (MME), a serving-gateway (S-GW), and a packet data network-gateway (PDN-GW). The MME has information about the access information of the terminal or the capability of the terminal, and this information is mainly used for mobility management of the terminal. S-GW is a gateway having an E-UTRAN as an endpoint, and PDN-GW is a gateway having a PDN (Packet Data Network) as an endpoint.

3 and 4 illustrate a control plane and a user plane (U-Plane, User-Plane) structure of a radio interface protocol between a terminal and an E-UTRAN based on the 3GPP radio access network standard. It is a figure which shows. In particular, the air interface protocol consists of a physical layer, a data link layer, and a network layer vertically, and horizontally a user plane and control for transmitting data information. It is divided into a control plane for transmitting a signal.

In addition, the protocol layers of FIGS. 3 and 4 are based on the Open System Interconnection (OSI) reference model, which is widely known in communication systems. The lower three layers are L1 (first layer) and L2 (second layer). , L3 (third layer).

The control plane means a path through which control messages used by the terminal and the network to manage a call are transmitted. The user plane refers to a path through which data generated at an application layer, for example, voice data or Internet packet data, is transmitted. Hereinafter, each layer of the control plane and the user plane of the radio protocol will be described.

The physical layer, which is the first layer, provides an information transfer service to an upper layer by using a physical channel. The physical layer is connected to the upper Media Access Control (MAC) layer through a transport channel. Data moves between the MAC layer and the physical layer through the transport channel. Data moves between the physical layer between the transmitting side and the physical side of the receiving side. The physical channel is modulated by an orthogonal frequency division multiplexing (OFDM) scheme and utilizes time and frequency as radio resources.

The MAC layer of the second layer provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel. The RLC layer of the second layer supports reliable data transmission. The functionality of the RLC layer may be implemented as a functional block inside the MAC. In this case, the RLC layer may not exist. The PDCP (Packet Data Convergence Protocol) layer of the second layer performs a header compression function to reduce unnecessary control information in order to efficiently transmit an IP packet such as IPv4 or IPv6 over a narrow bandwidth interface. .

The radio resource control (RRC) layer located at the bottom of the third layer is defined only in the control plane, and the configuration, re-configuration, and release of radio bearers (RBs) are performed. Responsible for control of logical channels, transport channels and physical channels in connection with. The radio bearer refers to a service provided by the second layer for data transmission between the terminal and the E-UTRAN. To this end, the RRC layer exchanges RRC messages between the terminal and the network.

In FIG. 3, the non-access stratum (NAS) layer above the RRC layer performs functions such as session management and mobility management. The NAS layer is present in a mobility management entity (MME) of a terminal and a network.

MME is a key control-node in LTE access networks. The MME is responsible for tracking and paging processes for the terminal in the idle state. The MME is also involved in the radio bearer activation / deactivation process and is responsible for selecting a Serving Gateway (SGW) for UEs during 'Initial Attach' or during intra-LTE handovers including core network relocation. Together. The MME is responsible for terminal authentication through interaction with a Home Subscriber Server (HSS). NAS signaling is terminated in the MME, the MME is responsible for generating a temporary identifier and assigning to the terminal. The MME checks whether the UE has a right to camp on a PLMN (Public Land Mobile Network) of the service provider. The MME is the endpoint for encryption / integrity protection for NAS signaling in the network and is responsible for security key management. MME provides control plane functionality for mobility between LTE and 2G / 3G access networks.

In the NAS layer, two states are defined for ESM (EPS Mobility Management) registered state (EMM-REGISTERED) and EMM unregistered state (EMM-UNREGISTERED) for the mobility management of the UE, and these two states are applied to the UE and the MME. The initial terminal is in an EMM unregistered state, and the terminal performs a process of registering with the corresponding network through an initial attach procedure to access the network. If the contact procedure is successfully performed, the UE and the MME are in the EMM registration state.

In addition, the NAS layer defines two types of EPS connection management (ECM) idle state (ECM_IDLE) and ECM_CONNECTED (ECM_CONNECTED) in order to manage a signaling connection between the UE and the EPC. These two states are the UE and the MME. Applies to When the UE in the ECM idle state makes an RRC connection with the E-UTRAN, the UE is in the ECM connection state. The MME, which is in the ECM idle state, becomes an ECM connection state when it establishes an S1 connection with E-UTRAN. When the terminal is in the ECM dormant state, the E-UTRAN does not have a context of the terminal. Accordingly, the UE in the ECM idle state performs a UE-based mobility related procedure such as a cell selection or cell reselection procedure without receiving a command from the network. On the other hand, when the terminal is in the ECM connection state, the mobility of the terminal is managed by the command of the network. In the ECM idle state, when the location of the terminal is different from the location known by the network, the terminal informs the network of the corresponding location of the terminal through a TA update (Tracking Area Update) procedure.

5 is a diagram showing the structure of a dual-mode terminal of the present invention.

Referring to FIG. 5, a dual mode terminal may include an application processor, an LTE processor for processing a signal received from an LTE network, and a CDMA processor for processing a signal received from a CDMA network.

The application processor may be configured as a module in hardware within the dual mode terminal, or may be included in a PC and configured independently of the dual mode terminal. In addition, the application processor may include a connection manager (CM) for managing and controlling the connection state to the CDMA network or LTE network according to the network environment.

More specifically, the CM performs a switching role for transmitting and receiving data between an application and one of two processors (CDMA processor or LTE processor) according to a network connection state. That is, when the dual mode terminal is connected to the CDMA network, the application data is transmitted and received through the A interface so that the CDMA processor and the application are connected. When the dual mode terminal is connected to the LTE network, the application data is transmitted to the LTE processor. Send and receive over the B interface so that the application is connected.

The host interface is located between the CDMA processor and the LTE processor, and may be used for transmitting control signals and data signals between the processors.

In general, LTE networks can transmit and receive data faster than CDMA networks. Therefore, CM prefers to connect to LTE network over CDMA network. Therefore, the CM uses the LTE network when the CDMA network and the LTE network are mixed. That is, even when connected to the CDMA network, the CM periodically searches for the LTE network and attempts to connect to the found LTE network. This method is described in detail with reference to FIG.

6 is a flowchart illustrating a method of repeatedly attempting to connect to an LTE network while connected to a CDMA network by a general method.

In step S601, the dual mode terminal releases the connection to the CDMA network in order to attempt to access the LTE network. In other words, when data is transmitted / received through the CDMA network, data transmission / reception becomes impossible from step S601.

In step S602, the dual mode terminal searches for at least one LTE cell. In operation S603, the dual mode terminal reads a master information block (MIB) and / or system information blocks (SIBs) from the cell found in operation S602.

In operation S604, the dual mode terminal measures the strength of a signal received from the LTE cell. For example, the strength of the received signal may be a reference signal received power (RSRP) value.

The information read in step S603 and the value measured in step S604 are used in step S605, where it is determined whether to attach to the LTE cell providing the information.

In step S605, the dual mode terminal determines whether the strength of the received signal measured in step S604 is sufficient.

An example of the process determined in step S605 may be determined by comparing the SIB information received in step S603 with the RSRP measured in step S604. Table 1 below shows 3GPP TS 36.304 chap. The types of parameters included in the SIB of 5.2.3.2 are shown.

Srxlev Cell selection RX level value (dB) Squal Cell selection quality value (dB) Q _rxlevmeas Measured cell RX level value (RSRP) Q _qualmeas Measured cell quality value (RSRQ) Q _rxlevmin Minimum required RX level in the cell (dBm) Q _qualmin Minimum required quality level in the cell (dB) Q _{rxlevminoffset} Offset to the signaled Q _rxlevmin taken into account in the Srxlev evaluation as a result of a periodic search for a higher priority PLMN while camped normally in a VPLMN [5] Q _{qualminoffset} Offset to the signaled Q _qualmin taken into account in the Squal evaluation as a result of a periodic search for a higher priority PLMN while camped normally in a VPLMN [5] Pcompensation max (P _EMAX -P _PowerClass , 0) (dB) P _EMAX Maximum TX power level an UE may use when transmitting on the uplink in the cell (dBm) defined as P _EMAX in [TS 36.101] P _PowerClass Maximum RF output power of the UE (dBm) according to the UE power class as defined in [TS 36.101]

Among the parameters included in the SIB of Table 1, "Q _rxlevmin " represents the minimum value of the received signal required by the cell. Therefore, in operation S605, the dual mode terminal may determine whether the measured RS is sufficient by comparing the _RSRP value with the Q _rxlevmin value.

According to the determined result, if the measured strength of the received signal is not enough, return to S602 without attempting to attach to the LTE cell to search for a new LTE cell again.

If the strength of the received signal measured in step S605 is sufficient, the dual mode terminal may enter the step S606, may attempt to attach to the retrieved LTE cell. If the dual mode terminal succeeds in attaching, it proceeds to step S607 and camps in the successful LTE cell.

Attempted to attach to the retrieved LTE cell in step S606, but fails, the dual mode terminal proceeds to step S608. In step S608, the dual mode terminal recovers the connection to the CDMA network. This is because the data is not transmitted or received because the connection to the CDMA network is released in step S601 to search for the LTE cell. Since the connection to the preferred LTE network has failed, the connection of the CMDA network, which is the original network, is restored.

In step S609, the dual mode terminal transmits and receives data in a CDMA network which is an existing network.

On the other hand, since a predetermined time elapses, whether or not it can be attached to the LTE cell may change again, and thus, attempts to connect to the LTE cell again (step S610). Therefore, the dual mode terminal judges whether a predetermined time has elapsed in step S610, and continues to transmit and receive data on the CDMA network (step S609) before the elapsed time, and returns to S601 when the elapsed time passes, and releases the connection to the CDMA network. do. And by repeating the above process, it will try to connect to the LTE network again.

As described above with reference to FIG. 6, the dual mode terminal connected to the CDMA network cannot transmit / receive data from step S601 to step S609 during a process for attempting to connect to the LTE network. In general, the time required from step S601 to step S609 is about 10 seconds. Therefore, when repeatedly attempting to connect to the LTE network, the user cannot be connected to continuous data communication.

Therefore, in the exemplary embodiments of the present invention, it is proposed to determine the wireless communication environment of the terminal and to control the period of attempting to connect to the LTE network according to whether the determined wireless communication environment is changed. That is, when the wireless communication environment does not change, the connection period to the LTE network is gradually increased to provide a continuous connection of data communication. Embodiments of the present invention will be described with reference to the accompanying drawings.

7 is a flowchart illustrating a method for repeatedly connecting to an LTE network while connected to a CDMA network according to an embodiment of the present invention. Steps S701 to S707 are similar to steps S601 to S607 of FIG. 6.

In step S701, the dual mode terminal releases the connection to the CDMA network in order to attempt to access the LTE network. In other words, when data is transmitted / received through the CDMA network, data transmission / reception becomes impossible from step S701.

In step S702, the dual mode terminal searches for at least one LTE cell. In step S703, the dual mode terminal reads the MIB and / or system information blocks (SIBs) from the cell found in step S702.

In operation S704, the dual mode terminal measures the strength of a signal received from the LTE cell. For example, the strength of the received signal may be a reference signal received power (RSRP) value.

The information read in step S703 and the value measured in step S704 are used in step S705. In this step, it is determined whether to attach to the LTE cell providing the information.

In operation S705, the dual mode terminal determines whether the strength of the received signal measured in operation S704 is sufficient.

An example of the process determined in step S705 may be determined by comparing the SIB information received in step S703 with the RSRP measured in step S704. As described above with reference to FIG. 6, in operation S705, the dual mode terminal may determine whether the measured RS has sufficient strength by comparing the _RSRP value with the Q _rxlevmin value.

According to the determined result, if the measured strength of the received signal is not enough, return to S702 without attempting to attach to the LTE cell to search for a new LTE cell again.

If the strength of the received signal measured in step S705 is sufficient, the dual mode terminal may enter the step S706, and attempt to attach to the retrieved LTE cell. When the dual mode terminal succeeds in attaching, the mobile terminal proceeds to step S707 and camps in the LTE cell where the attach is successful.

If the attachment fails in step S706, the flow proceeds to step S708.

In step S708, the dual mode terminal compares the communication environment information and the stored communication environment information for the LTE network that failed to attach. The communication environment information is information indicating a wireless communication state for the LTE network, and may include at least one of information for identifying an LTE network such as a cell ID and a frequency band of an LTE base station. .

The communication environment information may include values of parameters such as "Qrxlevmin" described above with reference to Table 1 or RSRP values actually measured by the terminal among parameters included in the SIBs received by the dual mode terminal. That is, if there is a change in the parameter value or the measured value, the possibility of access to the LTE network may be different.

The communication environment information may include identification information of the CDMA network which is returned again. For example, it may include a frequency band of a returned CDMA network or a cell ID of a base station.

Furthermore, it may include the time and / or date of returning to the CDMA network. The dual mode terminal may compare only recent information among stored communication environment information using time and / or date information.

In step S708, the reason for comparing the communication environment information is that if the wireless communication state at the time of the previous connection failure and the current wireless communication state have not changed, the possibility of successful connection is low. Therefore, it is proposed in embodiments of the present invention to increase the period of attempting to connect when the wireless communication state does not change when the connection to the LTE cell fails repeatedly. This step of increasing the cycle will be described in steps S709 and S710.

In particular, the reason for comparing the cell ID is that the wireless communication state changes with the movement of the position of the dual mode terminal. That is, when the user moves from the first cell to the second cell with the dual mode terminal, the cell ID is changed from the first cell ID to the second cell ID, and thus the wireless communication state is changed.

That is, in step S708, if the communication environment information at the time when the attachment fails immediately before is identical to the communication environment information at the time when the failure in step S706 is the same, proceeds to step S709. In step S709, the dual mode terminal stores communication environment information that failed in step S706. The stored communication environment information may be used as a comparison target at the next connection attempt.

In step S710, the dual mode terminal increases the access period T. Although an example was given on the flowchart by the method of making T + Δ to the connection period T, there is no limitation on the method of increasing. Thus, other examples may be exponentially increased or multiplied by multiples.

In step S711, the dual mode terminal recovers the connection to the CDMA network. This is because the data is not transmitted or received because the connection to the CDMA network is released in step S601 to search for the LTE cell. Since the connection to the preferred LTE network has failed, the connection of the CMDA network, which is the original network, is restored.

In operation S712, the dual mode terminal transmits and receives data in a CDMA network, which is an existing network.

On the other hand, if time T elapses, whether or not it can be attached to the LTE cell can be changed again, and thus attempts to connect to the LTE cell again (step S713). Therefore, the dual mode terminal judges whether time T has elapsed in step S713, and continues to transmit and receive data on the CDMA network if it has elapsed (return to S712), and returns to S701 to release the connection to the CDMA network after elapse. do. And by repeating the above process, it will try to connect to the LTE network again.

In the flowchart of FIG. 7 according to an embodiment of the present invention, as the connection to the LTE cell fails, the period in which the connection is attempted is changed. As a result, unnecessary connection attempts can be minimized if the connection fails continuously without any change in the wireless communication environment.

When minimizing unnecessary connection attempts, as described above, discontinuity of data connection generated during connection attempts, message loss through IMS (IP Multimedia Subsystem), or minimization of power waste may be minimized. In addition, if packet paging comes down to the LTE network for VoLTE, the possibility of not receiving it may be minimized.

8 illustrates a block diagram of a terminal device according to an embodiment of the present invention.

Referring to FIG. 8, the terminal device 1000 includes a processor 1010, a memory 1020, an RF module 1030, a display module 1040, and a user interface module 1050. The terminal device 1000 is shown for convenience of description and some modules may be omitted. In addition, the terminal device 1000 may further include necessary modules. In addition, in the terminal device 1000, some modules may be classified into more granular modules. The processor 1010 may separately include an LTE processor for communicating with the LTE network and a CDMA processor for communicating with the CDMA network, and are configured to perform an operation according to the above-described embodiment of the present invention.

The memory 1020 is connected to the processor 1010 and stores an operating system, an application, program code, data, and the like. The RF module 1030 is connected to the processor 1010 and performs a function of converting a baseband signal into a radio signal or converting a radio signal into a baseband signal. To this end, the RF module 1030 performs analog conversion, amplification, filtering and frequency up-conversion, or a reverse process thereof. The display module 1040 is connected to the processor 1010 and displays various information. The display module 1040 may use well-known elements such as, but not limited to, a liquid crystal display (LCD), a light emitting diode (LED), and an organic light emitting diode (OLED). The user interface module 1050 is connected to the processor 1010 and may be configured with a combination of well-known user interfaces such as a keypad, a touch screen, and the like.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.

In this document, embodiments of the present invention have been mainly described based on data transmission / reception relations between a terminal and a base station. Certain operations described in this document as being performed by a base station may in some cases be performed by an upper node thereof. That is, it is apparent that various operations performed for communication with the terminal in a network including a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A base station may be replaced by terms such as a fixed station, a Node B, an eNode B (eNB), an access point, and the like. In addition, the terminal may be replaced with terms such as a user equipment (UE), a mobile station (MS), a mobile subscriber station (MSS), and the like.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In the case of a hardware implementation, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in a memory unit and driven by a processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit of the invention. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Claims (22)

A dual mode terminal operating in a wireless communication system including a first communication network and a second communication network,
A first wireless communication module for communicating with the first communication network;
A second wireless communication module for communicating with the second communication network; And
A processor for processing a signal received from the first communication network and a signal received from the second communication network,
The processor,
Communication environment information indicating a wireless communication state of the second communication network in a state in which connection to the second communication network is periodically attempted in the state of being connected to the first communication network, and the connection has failed in succession more than a preset number of times. If is the same as the previous connection attempt, increase the connection period,
The processor, in attempting to connect the second communication network,
Search for a first base station supporting the second communication network,
Receiving information including a minimum required strength value for attempting connection with a first base station from the retrieved first base station,
Measuring the strength of a signal received from the first base station,
Attempt to connect to the first base station if the measured signal strength is greater than the received minimum required strength value;
Searching for another second base station supporting the second communication network when the measured signal strength is less than the received minimum required strength value. Claim 2 has been abandoned upon payment of a set-up fee. The method of claim 1,
The communication environment information includes at least one of a cell ID (Cell ID), the frequency band (Frequency Band) of the first base station to attempt to connect to the second communication network. Claim 3 has been abandoned upon payment of a set-up fee. The method of claim 1, wherein the processor,
The dual mode terminal for initializing the connection period when the communication environment information indicating the wireless communication state of the second communication network is different from the previous connection attempt. Claim 4 has been abandoned upon payment of a setup registration fee. The method of claim 1,
The first communication network is a CDMA code divisional multiple access evolved high-rate packet data network. Claim 5 was abandoned upon payment of a set-up fee. The method of claim 1,
The second communication network is a dual mode terminal LTE (Long Term Evolution) network. Claim 6 has been abandoned upon payment of a setup registration fee. The method of claim 1, wherein the processor,
In increasing the access period, the dual mode terminal to increase by adding a predetermined value to the previous access period. Claim 7 was abandoned upon payment of a set-up fee. The system of claim 1, wherein the processor is
A dual mode terminal which is an exponentially increasing value in increasing the connection period. Claim 8 has been abandoned upon payment of a set-up fee. The method of claim 1,
The processor releases the connection with the first communication network when attempting to connect to the second communication network. Claim 9 was abandoned upon payment of a set-up fee. The method of claim 8,
If the processor fails to connect to the second communication network, the dual mode terminal recovers the connection with the first communication network again. delete delete delete delete delete delete delete delete delete delete delete delete delete

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