KR20120011761A - Method for receiving sms at dual mode device and apparatus therefor - Google Patents

Abstract

PURPOSE: A method for receiving an SMS(Short Message Service) in a dual mode terminal and a device thereof are provided to enable a dual mode terminal to receive an SMS. CONSTITUTION: A first wireless communication unit transceives a signal from a CDMA(Code Divisional Multiple Access) communication network. A second wireless communication unit transceives a signal from an LTE(Long Term Evolution) communication network. A processor(1010) processes a signal received from the LTE communication network and a signal received from the CDMA communication network. The processor sets time information of an SMS to which an error average is reflected as time information of an SMS received from the LTE communication network.

Description

Method for receiving SMS in dual mode terminal and apparatus therefor {METHOD FOR RECEIVING SMS AT DUAL MODE DEVICE AND APPARATUS THEREFOR}

The present invention relates to a dual mode terminal. More specifically, the present invention relates to a method for receiving a Short Message Service (SMS) in a dual mode terminal and an apparatus therefor.

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 or a data card type device (hereinafter, dual mode terminal) having a dual modem processor is required.

The dual mode terminal is equipped with two modems having different communication methods to support wireless communication using each of them, and is mainly used in a region 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 Code Divisional Multiple Access (CDMA) wireless communication has attracted attention. In the present invention, a description will be given on the assumption of a multi-mode device capable of communicating with both an LTE network and a CDMA network, but it is obvious to those skilled in the art that other types of wireless communication can be applied. It is true.

An object of the present invention is to provide an SMS receiving method and a device therefor in a dual mode terminal.

Technical problems to be achieved in the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In a wireless communication system according to an aspect of the present invention, a method of receiving a short message service (SMS) by a dual mode terminal may include receiving first time information from a first communication network; Receiving second time information from a second communication network; Calculating and storing an error average between the first time information and the second time information; And setting the value reflecting the error average to the time information included in the SMS as time information of the SMS received from the second communication network when receiving the SMS from the second communication network. The first communication network is a Code Divisional Multiple Access (CDMA) communication network, and the second communication network is a Long Term Evolution (LTE) communication network. In addition, it is assumed that when the SMS is received from the LTE communication network, signal transmission and reception with the CDMA communication network is impossible.

More preferably, when the time information of the SMS from the LTE network is earlier than the time information of the immediately received SMS, the time information of the SMS from the LTE network is set to the time information of the immediately received SMS. It may be characterized by further comprising the step.

Meanwhile, in a method of receiving a short message service (SMS) by a dual mode terminal in a wireless communication system according to another aspect of the present invention, long term LTE (LTE) in an area where signal transmission and reception with the CDMA communication network is impossible Evolution) receiving an SMS from a communication network; Obtaining time information included in the SMS; And setting a reception time stamp by reflecting the estimated transmission time from the LTE communication network to the dual mode terminal in the time information, wherein the estimated transmission time is determined by the base station information where the transmitter is located and the dual mode terminal. Characterized in that it is statistically calculated using the connected base station information.

In addition, a dual mode terminal of a wireless communication system according to an aspect of the present invention includes a first wireless communication unit for transmitting and receiving a signal from a Code Divisional Multiple Access (CDMA) communication network; A second wireless communication unit for transmitting and receiving a signal from a Long Term Evolution (LTE) communication network; And a processor for processing a signal received from the LTE communication network and a signal received from the CDMA communication network, wherein the processor includes first time information received from the CDMA communication network and second time information received from the LTE communication network. Compute and store the average of the error, and when receiving the SMS (Short Message Service) from the LTE network, to set the value reflecting the error average in the time information included in the SMS as the time information of the SMS received from the LTE network It is characterized by. Preferably, the processor, when the time information of the SMS from the LTE network is earlier than the time information of the immediately received SMS, the time of the SMS immediately received the time information of the SMS from the LTE network It is characterized by setting as information.

On the other hand, a dual mode terminal of a wireless communication system according to another aspect of the present invention includes a first wireless communication unit for transmitting and receiving signals from a Code Divisional Multiple Access (CDMA) communication network; A second wireless communication unit for transmitting and receiving a signal from a Long Term Evolution (LTE) communication network; And a processor for processing a signal received from the LTE communication network and a signal received from the CDMA communication network, wherein the processor receives the SMS from the LTE communication network in an area where signal transmission and reception with the CDMA communication network are impossible. Acquires time information included in an SMS, sets a reception time stamp by reflecting the estimated transmission time from the LTE communication network to the dual mode terminal in the time information, and the estimated transmission time is determined by the base station information where the transmitting side is located; And a value calculated statistically using the base station information to which the dual mode terminal is connected.

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 which shows.
5 is a diagram showing the structure of a dual-mode terminal of the present invention.
6 is a diagram illustrating a method for receiving an SMS in a conventional terminal device supporting only a CDMA communication network.
7 is a diagram illustrating a problem that may occur in a general dual mode terminal device.
8 is a diagram illustrating an SMS receiving method in a dual mode terminal device according to an embodiment of the present invention.
9 is a diagram illustrating a method for receiving an SMS in a dual mode terminal device according to another embodiment of the present invention.
10 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the 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 the following description, it is assumed that the UE collectively refers to a mobile stationary or stationary user equipment such as a UE (User Equipment) and an MS (Mobile Station). It is also assumed that the base station collectively refers to any node of a network end that communicates with a terminal such as a Node B, an eNode B, and a 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 the technical specifications of UMTS and E-UMTS, refer to Release 7 and Release 8 of "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 the NAS layer, two types of EPS connection management (ECM_IDLE) and ECM_CONNECTED (ECM_CONNECTED) are defined 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 the 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 LTE processor for processing a signal received from an application processor and 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.

6 is a diagram illustrating a method for receiving an SMS in a conventional terminal device supporting only a CDMA communication network.

Referring to FIG. 6, a conventional terminal device supporting only signal transmission and reception with a CDMA communication network receives time information from a synchronous CDMA communication network as in step 601 to obtain time synchronization. Thereafter, when the SMS is received from the CDMA communication network in step 602, the time at which the SMS is received, that is, the time stamp, may be displayed to the user based on the obtained time synchronization in step 603.

7 is a diagram illustrating a problem that may occur in a general dual mode terminal device.

Referring to FIG. 7, even in the case of a dual mode terminal device, in order to set a system time, time synchronization is obtained based on a CDMA communication network based on a synchronous method. Therefore, if the terminal device does not connect with the CDMA network during initial driving, the system time of the terminal device does not obtain time synchronization.

However, if the dual mode terminal is not connected to the CDMA communication network, since there is a high probability of being located in an area where only the connection with the LTE communication network is possible, SMS reception from the LTE communication network is possible. Of course, the LTE communication network also transmits time information, but there is a difference from the time information transmitted in the CDMA communication network. Since the LTE communication network is basically asynchronous, the time when the dual mode terminal receives the SMS, that is, the time stamp is incorrect. Problems may arise.

Hereinafter, a method of receiving an SMS in a dual mode terminal device for solving such a problem will be described.

8 is a diagram illustrating an SMS receiving method in a dual mode terminal device according to an embodiment of the present invention. It is assumed that the dual mode terminal device is located in an area accessible to both the CDMA communication network and the LTE communication network.

Referring to FIG. 8, first, as in step 801, time information is received from a synchronous CDMA communication network to obtain time synchronization. On the other hand, since the dual mode terminal device can be connected to the LTE communication network, it also receives time information from the LTE communication network.

In this case, as shown in step 802, an error between the time information received from the LTE communication network and the time information received from the CDMA communication network is calculated, and an error average value is stored as shown in Equation 1 below.

&Quot; (1) "

CDMA_LTE_Diff = average (CDMA time-LTE Time)

Accordingly, the dual mode terminal of the present invention is based on the time information received from the LTE network and the error average value based on the error average value when received from the LTE network even though the dual mode terminal is not connected to the CDMA network as shown in FIG. The time stamp can be calculated and displayed on the received SMS. This may be expressed as Equation 2 below.

<Equation 2>

Stamp Time = LTE Time + CDMA_LTE_Dif

9 is a diagram illustrating a method for receiving an SMS in a dual mode terminal device according to another embodiment of the present invention. In particular, FIG. 9 assumes that the dual mode terminal device is located in an area where only the connection with the LTE communication network is possible. Similarly, if the CDMA communication network cannot be connected during the initial operation of the dual mode terminal, the system time of the terminal device does not acquire time synchronization.

Referring to FIG. 9, the SMS received from the LTE communication network may include information regarding the time at which the transmitting side transmits the SMS. In this case, the reception time stamp may be calculated by adding the transmission estimated time to the transmission time.

Here, the estimated transmission time may be a value preset by the manufacturer of the terminal, or may be a value calculated statistically using the base station information on which the transmitting side is located and the base station information to which the dual mode terminal of the receiving side is connected.

That is, the time stamp finally calculated and displayed may be expressed as Equation 3 below.

&Quot; (3) &quot;

Stamp Time = SMS Sending Time + Transmission Duration Expectation Time

Meanwhile, the time stamp value calculated in Equations 2 and 3 may be calculated as a time earlier than the time stamp of the SMS just received by the dual mode terminal. In such a case, the dual mode terminal may determine that the time stamp is an error and replace the time stamp of the immediately received SMS with the time stamp of the received SMS.

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

Referring to FIG. 10, 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 implemented 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 configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. 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, the embodiments of the present invention have been mainly described with reference to the data transmission / reception relationship between the terminal and the base station. The specific operation described herein as being performed by the base station may be performed by its upper node, in some cases. That is, it is apparent that various operations performed for communication with a terminal in a network including a plurality of network nodes including a base station can be performed by a network node other than the base station or 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.

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 (10)

In a method for receiving a dual message terminal Short Message Service (SMS) in a wireless communication system,
Receiving first time information from a first communication network;
Receiving second time information from a second communication network;
Calculating and storing an error average between the first time information and the second time information; And
When receiving the SMS from the second communication network, setting the value reflecting the error average in the time information included in the SMS as time information of the SMS received from the second communication network,
How to receive SMS. The method of claim 1,
The first communication network is a code divisional multiple access (CDMA) communication network,
The second communication network is characterized in that the Long Term Evolution (LTE) communication network,
How to receive SMS. The method of claim 2,
When receiving an SMS from the LTE network, characterized in that the signal transmission and reception with the CDMA network is impossible,
How to receive SMS. The method of claim 2,
If the time information of the SMS from the LTE communication network is earlier than the time information of the immediately received SMS, setting the time information of the SMS from the LTE communication network to the time information of the immediately received SMS. Characterized by
How to receive SMS. In a method for receiving a dual message terminal Short Message Service (SMS) in a wireless communication system,
Receiving an SMS from a Long Term Evolution (LTE) communication network in an area where signal transmission and reception are not possible with the CDMA communication network;
Obtaining time information included in the SMS; And
And setting a reception time stamp by reflecting the estimated transmission time from the LTE communication network to the dual mode terminal in the time information.
The estimated transmission time is a value calculated statistically using the base station information where the transmitting side is located and the base station information to which the dual mode terminal is connected.
How to receive SMS. The method of claim 5, wherein
If the calculated reception time stamp is earlier than the reception time stamp of the immediately received SMS, setting the reception time stamp of the SMS from the LTE communication network to the reception time stamp of the immediately received SMS. Characterized in that,
How to receive SMS. As a dual mode terminal of a wireless communication system,
A first wireless communication unit for transmitting and receiving a signal from a Code Divisional Multiple Access (CDMA) communication network;
A second wireless communication unit for transmitting and receiving a signal from a Long Term Evolution (LTE) communication network; And
A processor for processing a signal received from the LTE communication network and a signal received from the CDMA communication network,
The processor comprising:
Compute and store the error average between the first time information received from the CDMA communication network and the second time information received from the LTE communication network, and time information included in the SMS when SMS (Short Message Service) is received from the LTE communication network. Characterized in that the value reflecting the error mean to the time information of the SMS received from the LTE communication network,
Dual mode terminal. The method of claim 7, wherein
When receiving an SMS from the LTE network, characterized in that the signal transmission and reception with the CDMA network is impossible,
Dual mode terminal. The method of claim 7, wherein
The processor comprising:
When the time information of the SMS from the LTE network is earlier than the time information of the immediately received SMS, the time information of the SMS from the LTE network is set to the time information of the immediately received SMS; ,
Dual mode terminal. As a dual mode terminal of a wireless communication system,
A first wireless communication unit for transmitting and receiving a signal from a Code Divisional Multiple Access (CDMA) communication network;
A second wireless communication unit for transmitting and receiving a signal from a Long Term Evolution (LTE) communication network; And
A processor for processing a signal received from the LTE communication network and a signal received from the CDMA communication network,
The processor comprising:
When receiving an SMS from the LTE communication network in an area where signal transmission and reception are not possible with the CDMA communication network, time information included in the SMS is obtained, and the estimated transmission time from the LTE communication network to the dual mode terminal is reflected in the time information. To set the reception timestamp,
The estimated transmission time is,
Characterized in that it is calculated statistically using the base station information that the transmitting side is located and the base station information connected to the dual-mode terminal,
Dual mode terminal.

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