KR20100084907A - Mobile terminal and synchronization obtaining method thereof - Google Patents

Abstract

PURPOSE: A mobile terminal and a synchronization obtaining method thereof are provided to accurately and quickly obtain system time during handover between heterogeneous networks, thereby synchronizing a network. CONSTITUTION: If power is turned on, an LTE(Long Term Evolution) modem(51) is connected to an LTE network. The LTE modem selects a cell. A CDMA modem(52) obtains system time by being synchronized with a CDMA network according to the synchronizing request signal during cell selection of the LTE modem. If handover occurs in the CDMA network in the LTE network, the CDMA modem synchronizes a call of a CDMA network using the obtained system time.

Description

MOBILE TERMINAL AND SYNCHRONIZATION OBTAINING METHOD THEREOF}

The present invention relates to a mobile terminal and a method for acquiring synchronization, which can acquire synchronization by quickly and accurately acquiring system time during handover between heterogeneous networks.

The mobile terminal may be configured to perform various functions. Examples of such various functions include data and voice communication functions, taking pictures or videos through a camera, storing voices, playing music files through a speaker system, and displaying images or videos.

Some mobile terminals include additional functionality to play games, while others are implemented as multimedia devices. Moreover, recent mobile terminals can receive broadcast or multicast signals to watch video or television programs.

In addition to the above functions, efforts are currently being made to support and increase the functions of the mobile terminal. The foregoing efforts include additions and improvements in software or hardware as well as changes and improvements in the structural components forming the mobile terminal.

The E-UMTS system is an evolution from the UMTS system and is undergoing basic standardization work in 3GPP. The E-UMTS system is also called a Long Term Evolution (LTE) system.

E-UMTS (LTE) network is divided into E-UTRAN and Core Network (CN). The E-UTRAN consists of a base station (eNode B or eNB), and the core network includes an access gateway (AG). The AG may be divided into a part for processing user traffic and a part for processing control traffic. In this case, the gateway for processing the user traffic and the gateway for controlling traffic may communicate with each other using a new interface. One or more cells may exist in one base station, and an interface for transmitting user traffic or control traffic may be used between base stations. The core network may be configured as a node for user registration of a gateway and other terminals (UEs).

LTE is a state-of-the-art communication technology designed to download a large amount of data. Unlike WCDMA and GSM, LTE uses a multi-antenna algorithm called a multiple input multiple output (MIMO).

Recently, in accordance with increased communication technology and user desire, dual mode terminals supporting at least one communication mode (LTE / CDMA) or single / dual wireless RF have been released to support handover between heterogeneous networks, for example, LTE and CDMA. Doing. The handover is a function for allowing the user to continue to communicate even when the user moves from the first area to a second area accessing a network different from the first area.

On the other hand, in the CDMA system, the system time is used as a reference time required for synchronization. Accordingly, the dual mode terminal supporting the CDMA mode can identify the pilot PN (Pseudo random noise sequence) offset using the system time, and based on this, it synchronizes with the cell / sector where it is currently located. Camp on can be performed accordingly. .

Therefore, when the mobile terminal supporting LTE / CDMA dual-dod is handed over from the LTE network to the CDMA network in an environment in which an LTE network serving as a hotspot in the CDMA network is mixed, the mobile terminal camps on. A new cell is found to identify the optimal pilot PN (Pseudo random Noise sequence) offset to obtain synchronization. Once sync is established, the system time of CDMA can be found on the sync channel.

However, conventionally, it takes too much time to acquire the system time by searching for the optimal pilot PN offset when handing over from LTE to CDMA, and when the system time is interfaced from LTE to CDMA, it is used in LTE. The disadvantage was that the system time was not updated correctly towards CDMA.

An object of the present invention is to provide a mobile terminal and a synchronization method thereof capable of aligning a network by obtaining a system time more quickly and accurately during handover between heterogeneous networks.

According to an aspect of the present invention, there is provided a synchronization obtaining method of a mobile terminal, comprising: performing a cell selection by connecting a first modem to a first network when power is turned on; Acquiring a system time in synchronization with a second network in a second modem while performing cell selection of the first modem; When a handover occurs from the first network to a second network, transmitting a handover command from the first modem to a second modem; Synchronizing a call of a second network using the system time obtained by the second modem according to the handover command.

Preferably, the first and second networks are heterogeneous networks, the first network is an LTE network, and the second network is a CDMA network.

Preferably, the first and second networks are heterogeneous networks, the first network is a CDMA network, and the second network is an LTE network.

Preferably, the network that preferentially performs the cell selection is determined by the user's menu selection.

Preferably, when the power is turned on, the second modem receives a synchronization request signal transmitted periodically from the connection manager to obtain synchronization with the second network.

According to an aspect of the present invention, there is provided a mobile terminal comprising: a first modem connected to a first network to perform cell selection when power is turned on; A connection manager for periodically generating a synchronization request signal; While performing the cell selection of the first modem, the system time is acquired in synchronization with the second network according to the synchronization request signal, and when the handover from the first network to the second network occurs, the acquired system time It includes a second modem to synchronize to the call of the second network using.

Preferably, the first and second networks are heterogeneous networks, the first network is an LTE network, and the second network is a CDMA network.

Preferably, the first and second networks are heterogeneous networks, the first network is a CDMA network, and the second network is an LTE network.

Preferably, the network that preferentially performs the cell selection is determined by the user's menu selection.

Preferably, the connection manager generates a sync request signal periodically when the power is turned on, and stops generating the sync request signal when the sync complete signal is input from the second modem.

According to an embodiment of the present invention, a mobile terminal and a method for acquiring synchronization thereof may be previously synchronized with a CDMA network in a CDMA modem while an LTE modem accesses an LTE network and performs a call selection procedure in an LTE preference environment. By acquiring the system time, when a handover occurs from LTE to CDMA, the system time can be used to quickly and accurately synchronize a call of the CDMA network.

Hereinafter, a mobile terminal according to the present invention will be described in more detail with reference to the accompanying drawings. The suffixes "module" and "unit" for components used in the following description are merely given in consideration of ease of preparation of the present specification, and do not impart any particular meaning or role by themselves. Therefore, it should be noted that the "module" and "unit" may be used interchangeably with each other.

The terminal may be implemented in various forms. For example, a terminal described herein includes a mobile terminal such as a mobile phone, a smart phone, a notebook computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, and the like. And fixed terminals such as digital TVs, desktop computers, and the like. In the following description, it is assumed that the terminal is a mobile terminal. However, it will be readily apparent to those skilled in the art that the configuration according to the following description may also be applied to the fixed terminal except for components specially configured for mobile use.

1 is a block diagram of a mobile terminal according to an embodiment of the present invention.

The mobile terminal 100 includes a wireless communication unit 110, an A / V input unit 120, a user input unit 130, a sensing unit 140, an output unit 150, a memory 160, and an interface. The unit 170, the controller 180, and the power supply unit 190 may be included. 1 illustrates a mobile terminal having various components. However, not all illustrated components are required. The mobile terminal may be implemented by more components than the illustrated components, or the mobile terminal may be implemented by fewer components.

Hereinafter, the components will be described in turn.

The wireless communication unit 110 may include one or more components for wireless communication between the mobile terminal 100 and the wireless communication system or wireless communication between the mobile terminal 100 and a network in which the mobile terminal 100 is located. For example, the wireless communication unit 110 may include a broadcast receiving module 111, a mobile communication module 112, a wireless Internet module 113, a short range communication module 114, and a location information module 115 .

The broadcast receiving module 111 receives a broadcast signal and / or broadcast related information from an external broadcast management server through a broadcast channel. The broadcast channel may include a satellite channel and a terrestrial channel. The broadcast management server may mean a server that generates and transmits a broadcast signal and / or broadcast related information or a server that receives a previously generated broadcast signal and / or broadcast related information and transmits the same to a terminal. The broadcast related information may mean information related to a broadcast channel, a broadcast program, or a broadcast service provider. The broadcast signal may include not only a TV broadcast signal, a radio broadcast signal, and a data broadcast signal, but also a broadcast signal having a data broadcast signal combined with a TV broadcast signal or a radio broadcast signal.

Meanwhile, the broadcast related information may be provided through a mobile communication network, and in this case, may be received by the mobile communication module 112.

The broadcast related information may exist in various forms. For example, it may exist in the form of Electronic Program Guide (EPG) of Digital Multimedia Broadcasting (DMB) or Electronic Service Guide (ESG) of Digital Video Broadcast-Handheld (DVB-H).

The broadcast receiving module 111 receives broadcast signals using various broadcasting systems, and in particular, digital multimedia broadcasting-terrestrial (DMB-T), digital multimedia broadcasting-satellite (DMB-S), and media forward link (MediaFLO). Digital broadcast signals can be received using digital broadcasting systems such as only), digital video broadcast-handheld (DVB-H), integrated services digital broadcast-terrestrial (ISDB-T), and the like. Of course, the broadcast receiving module 111 is configured to be suitable for all broadcasting systems that provide broadcasting signals as well as the digital broadcasting system described above.

The broadcast signal and / or broadcast related information received through the broadcast receiving module 111 may be stored in the memory 160.

In addition, the mobile communication module 112 transmits and receives a radio signal with at least one of a base station, an external terminal, and a server on a mobile communication network. The wireless signal may include various types of data according to transmission and reception of a voice call signal, a video call call signal, or a text / multimedia message.

The wireless Internet module 113 is a module for wireless Internet access, and the wireless Internet module 113 can be built in or externally. Wireless Internet technologies may include Wireless LAN (Wi-Fi), Wireless Broadband (Wibro), World Interoperability for Microwave Access (Wimax), High Speed Downlink Packet Access (HSDPA), and the like.

The short range communication module 114 refers to a module for short range communication. As a short range communication technology, Bluetooth, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, and the like may be used.

In addition, the location information module 115 is a module for checking or obtaining the location of the mobile terminal. A representative example of the location information module 115 is a GPS (Global Position System) module. According to the current technology, the GPS module calculates distance information and accurate time information from three or more satellites, and then applies triangulation to the calculated information, thereby obtaining three-dimensional current position information according to latitude, longitude, and altitude. It can be calculated accurately. Currently, a method of calculating position and time information using three satellites and correcting the error of the calculated position and time information using another satellite is widely used. In addition, the GPS module may calculate speed information by continuously calculating the current position in real time.

Meanwhile, the A / V input unit 120 is for inputting an audio signal or a video signal, and may include a camera 121 and a microphone 122. The camera 121 processes image frames such as still images or moving images obtained by an image sensor in a video call mode or a photographing mode. The processed image frame may be displayed on the display module 151.

The image frame processed by the camera 121 may be stored in the memory 160 or transmitted to the outside through the wireless communication unit 110. Two or more cameras 121 may be provided according to the configuration aspect of the terminal.

The microphone 122 receives an external sound signal by a microphone in a call mode, a recording mode, a voice recognition mode, etc., and processes the external sound signal into electrical voice data. The processed voice data may be converted into a form transmittable to the mobile communication base station through the mobile communication module 112 and output in the call mode. The microphone 122 may implement various noise removing algorithms for removing noise generated in the process of receiving an external sound signal.

The user input unit 130 generates input data for the user to control the operation of the terminal. The user input unit 130 may include a key pad, a dome switch, a touch pad (constant voltage / capacitance), a jog wheel, a jog switch, and the like. In particular, when the touch pad forms a mutual layer structure with the display module 151 described later, this may be referred to as a touch screen.

The sensing unit 140 detects a current state of the mobile terminal 100 such as an open / closed state of the mobile terminal 100, a position of the mobile terminal 100, presence or absence of a user contact, orientation of the mobile terminal, acceleration / deceleration of the mobile terminal, and the like. To generate a sensing signal for controlling the operation of the mobile terminal 100. For example, when the mobile terminal 100 is in the form of a slide phone, it may sense whether the slide phone is opened or closed. In addition, it is responsible for sensing functions related to whether the power supply unit 190 is supplied with power or whether the interface unit 170 is coupled to an external device. The sensing unit 140 may include a proximity sensor 141. This will be described later with reference to the touch screen.

The interface unit 170 serves as an interface with all external devices connected to the mobile terminal 100. For example, wired / wireless headset ports, external charger ports, wired / wireless data ports, memory card ports, ports for connecting devices with identification modules, audio input / output (I / O) ports, Video I / O (Input / Output) port, earphone port, etc. may be included.

Here, the identification module is a chip that stores various types of information for authenticating the use authority of the mobile terminal 100, and includes a user identification module (UIM) and a subscriber identify module (SIM). ), A Universal Subscriber Identity Module (“USIM”), and the like. In addition, the device equipped with the identification module (hereinafter, 'identification device') may be manufactured in the form of a smart card. Therefore, the identification device may be connected to the terminal 100 through a port. The interface unit 170 receives data from an external device or receives power and transmits the data to each component inside the mobile terminal 100 or transmits the data inside the mobile terminal 100 to an external device.

In addition, when the mobile terminal 100 is connected to an external cradle, the interface unit 170 serves as a passage through which power from the cradle is supplied to the mobile terminal 100 or inputted from the cradle by a user. Various command signals may be a passage for transmitting to the mobile terminal. Various command signals or power input from the cradle may be operated as signals for recognizing that the mobile terminal is correctly mounted on the cradle.

The output unit 150 is for outputting an audio signal, a video signal, or an alarm signal. The output unit 150 may include a display module 151, a sound output module 152, and an alarm unit 153.

The display module 151 displays and outputs information processed by the mobile terminal 100. For example, when the mobile terminal is in a call mode, a user interface (UI) or a graphic user interface (GUI) related to a call is displayed. When the mobile terminal 100 is in a video call mode or a photographing mode, the mobile terminal 100 displays a photographed and / or received image, a UI, or a GUI.

Meanwhile, as described above, when the display module 151 and the touch pad have a mutual layer structure and constitute a touch screen, the display module 151 may be used as an input device in addition to the output device. The display module 151 may be a liquid crystal display, a thin film transistor-liquid crystal display, an organic light-emitting diode, a flexible display, or a three-dimensional display. 3D display). Some of these displays can be configured to be transparent so that they can be seen from the outside. This may be referred to as a transparent display. A representative example of the transparent display is a transparent organic light emitting diode (TOLED). In addition, two or more display modules 151 may exist according to the implementation form of the mobile terminal 100. For example, an external display module (not shown) and an internal display module (not shown) may be simultaneously provided in the mobile terminal 100. The touch screen may be configured to detect a touch input pressure as well as a touch input position and area.

The sound output module 152 outputs audio data received from the wireless communication unit 110 or stored in the memory 160 in a call signal reception, a call mode or a recording mode, a voice recognition mode, a broadcast reception mode, and the like. In addition, the sound output module 152 outputs a sound signal related to a function (eg, a call signal reception sound, a message reception sound, etc.) performed in the mobile terminal 100. The sound output module 152 may include a speaker, a buzzer, and the like.

The alarm unit 153 outputs a signal for notifying occurrence of an event of the mobile terminal 100. Examples of events occurring in the mobile terminal include call signal reception, message reception, key signal input, and touch input. The alarm unit 153 may output a signal for notifying occurrence of an event in a form other than an audio signal or a video signal. For example, the signal may be output in the form of vibration. When a call signal is received or a message is received, the alarm unit 153 may output a vibration to inform this. Alternatively, when a key signal is input, the alarm unit 153 may output a vibration in response to the key signal input. The vibration output as described above allows a user to recognize an event occurrence. Of course, the signal for notification of event occurrence may be output through the display module 151 or the sound output module 152.

The memory 160 may store a program for processing and controlling the controller 180 and may provide a function for temporarily storing input / output data (for example, a phone book, a message, a still image, a video, etc.). It can also be done. In addition, the memory 160 may store data on vibration and sound of various patterns output when a touch input on the touch screen is performed.

The memory 160 may be a flash memory type, a hard disk type, a multimedia card micro type, a card type memory (for example, SD or XD memory), RAM (RAM, Random Access Memory) SRAM (Static Random Access Memory), ROM (Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), PROM (Programmable Read-Only Memory) magnetic memory, magnetic disk, It may include at least one type of storage medium of the optical disk. In addition, the mobile terminal 100 may operate a web storage that performs a storage function of the memory 160 on the Internet.

The controller 180 typically controls the overall operation of the mobile terminal. For example, perform related control and processing for voice calls, data communications, video calls, and the like. In addition, the controller 180 may include a multimedia module 181 for playing multimedia. The multimedia module 181 may be implemented in the controller 180 or may be implemented separately from the controller 180.

The controller 180 may perform a pattern recognition process for recognizing a writing input or a drawing input performed on the touch screen as text and an image, respectively.

The power supply unit 190 receives the external power and the internal power under the control of the controller 180 as a battery and supplies power required for the operation of each component.

Various embodiments described herein may be implemented in a recording medium readable by a computer or similar device using, for example, software, hardware or a combination thereof.

According to a hardware implementation, embodiments described herein include application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), and the like. It may be implemented using at least one of processors, controllers, micro-controllers, microprocessors, and electrical units for performing the functions. It may be implemented by the controller 180.

In a software implementation, embodiments such as procedures or functions may be implemented with separate software modules that allow at least one function or operation to be performed. The software code may be implemented by a software application written in a suitable programming language. In addition, the software codes may be stored in the memory 160 and executed by the control unit 180. [

In the above, the mobile terminal related to the present invention has been described in terms of components according to functions. Hereinafter, referring to FIGS. 2 and 3, the mobile terminal related to the present invention will be further described in terms of components according to appearance. Hereinafter, for simplicity, a slider type mobile terminal is described as an example among various types of mobile terminals such as a folder type, a bar type, a swing type, a slider type, and the like. Therefore, the present invention is not limited to the slider type mobile terminal, but can be applied to all types of mobile terminals including the above-described type.

2 is a front perspective view of an example of a mobile terminal according to the present invention;

The mobile terminal 100 of the present invention includes a first body 200 and a second body 205 configured to be slidable in at least one direction on the first body 200. In the case of a folder phone, the mobile terminal 100 will include a first body and a second body configured to be folded or unfolded on at least one side of the first body.

A state in which the first body 200 is disposed to overlap with the second body 205 may be referred to as a closed configuration, and as shown in the drawing, the first body 200 may be referred to as the second body 205. The exposed state of at least a portion of the N may be referred to as an open configuration.

Meanwhile, although not shown in the drawings, the mobile terminal related to the present invention may be a folder type including a first body and a second body configured to be folded or unfolded on at least one side of the first body. . Here, a state in which the second body is folded may be referred to as a closed state, and a state in which the second body is configured to be unfolded may be referred to as an open state.

Furthermore, the mobile terminal associated with the present invention may be a swing type including a first body and a second body configured to swing relative to the first body, although not shown in the drawings. Here, a state in which the first body is disposed to overlap the second body may be referred to as a closed state, and a state in which a portion of the first body is exposed by swinging the second body may be referred to as an open state.

The terminal according to the folder type and the swing type is considered to be easily understood by those skilled in the art even if there is no separate description, so a detailed description thereof will be omitted.

The mobile terminal 100 operates mainly in the standby mode in a closed state, but the standby mode may be released by a user's manipulation. In addition, although the mobile terminal 100 operates mainly in a call mode or the like in an open state, the mobile terminal 100 may be switched to a standby mode by a user's manipulation or a lapse of a predetermined time.

The case (casing, housing, cover, etc.) forming the exterior of the first body 200 is formed by the first front case 220 and the first rear case 225. Various electronic components are embedded in the space formed by the first front case 220 and the first rear case 225. At least one intermediate case may be further disposed between the first front case 220 and the first rear case 225.

The cases may be formed by injecting a synthetic resin or may be formed of a metal material, for example, a metal material such as stainless steel (STS) or titanium (Ti).

The display unit 151, the audio output module 152, the camera 121, or the first user input unit 210 may be disposed on the first body 200, specifically, the first front case 220.

Since the display unit 151 has already been described with reference to FIG. 1, a detailed description thereof will be omitted for simplicity of the present specification.

The sound output module 152 may be implemented in the form of a speaker.

The camera 121 may be implemented to be suitable for capturing an image or a video of a user or the like.

Like the first body 200, the case forming the exterior of the second body 205 is formed by the second front case 230 and the second rear case 235.

The second user input unit 215 may be disposed on the second body 205, specifically, on the front face of the second front case 230.

The third user input unit 245, the microphone 122, and the interface unit 170 may be disposed on at least one of the second front case 230 or the second rear case 235.

The first to third user input units 210, 215, and 245 may be collectively referred to as the user input unit 130, and may be employed in any manner as long as the user is operating in a tactile manner. .

For example, the user input unit may be implemented as a dome switch or a touch pad capable of receiving a command or information by a user's push or touch operation, or a wheel or jog method of rotating a key, or a manipulation method such as a joystick. May also be implemented.

In functional terms, the first user input unit 210 is for inputting a command such as start, end, scroll, etc., and the second user input unit 215 is for inputting numbers, letters, symbols, and the like. The first user input unit 210 includes a so-called soft key used in conjunction with icons displayed on the display unit 151 and a navigation key (mainly composed of four direction keys and a center key) for direction indication and confirmation. can do.

In addition, the third user input unit 245 may operate as a hot-key for activating a special function in the mobile terminal.

The microphone 122 may be implemented in a form suitable for receiving a user's voice, other sounds, and the like.

The interface unit 170 serves as a path allowing the mobile terminal 100 according to the present invention to exchange data with an external device. Since the interface unit 170 has been described above with reference to FIG. 1, a detailed description thereof will be omitted.

The power supply unit 190 for supplying power to the mobile terminal 100 is mounted on the second rear case 235 side.

The power supply unit 190 may be detachably coupled for charging, for example, as a rechargeable battery.

3 is a rear perspective view of the mobile terminal of FIG. 2.

Referring to FIG. 3, a camera 121 may be additionally mounted on the rear surface of the second rear case 235 of the second body 205. The camera 121 of the second body 205 has a photographing direction substantially opposite to that of the camera 121 of the first body 200, and different pixels from the camera 121 of the first body 200. Can have

For example, the camera 121 of the first body 200 has a low pixel so that it is easy to take a picture of the user's face and transmit it to the counterpart in the case of a video call, and the camera 121 of the second body has a general structure. It is desirable to have a high pixel because the subject is often photographed and not immediately transmitted.

The flash 250 and the mirror 255 may be further disposed adjacent to the camera 121 of the second body 205. The flash 250 illuminates the subject when the subject is photographed by the camera 121 of the second body 205. The mirror 255 allows the user to see the user's face or the like when photographing (self-photographing) the user by using the camera 121 of the second body 205.

The sound output module 152 may be further disposed on the second rear case 235.

The sound output module 152 of the second body 205 may implement a stereo function together with the sound output module 152 of the first body 200, and may be used for a call in a speakerphone mode.

In addition, an antenna 260 for receiving broadcast signals may be disposed on one side of the second rear case 235. The antenna 260 may be installed to be pulled out of the second body 205.

A portion of the slide module 265 that slidably couples the first body 200 and the second body 205 is disposed on the first rear case 225 side of the first body 200.

The other part of the slide module 265 may be disposed on the second front case 230 side of the second body 205 and may not be exposed to the outside as shown in the drawing.

In the above description, the second camera 121 and the like have been described as being disposed in the second body 205, but the present invention is not limited thereto.

For example, at least one or more of the components 260, 121 to 250, and 152 described as disposed on the second rear case 235, such as the camera 121 of the second body, may be the first body 200, mainly. May be mounted on the first rear case 225. If so, there is an advantage that the configuration (s) disposed in the first rear case 225 in the closed state are protected by the second body 205. Furthermore, even if the camera 121 of the second body is not provided separately, the camera 121 of the first body may be rotatably formed so that the camera 121 of the second body may be photographed up to the photographing direction of the camera 121 of the second body. .

The terminal 100 illustrated in FIGS. 1 to 3 may be operated in a communication system capable of transmitting data through a frame or packet, including a wired / wireless communication system and a satellite-based communication system. It can be configured to.

Hereinafter, referring to FIG. 4, a communication system capable of operating a terminal according to the present invention will be described.

The communication system may use different air interfaces and / or physical layers. For example, a radio interface usable by a communication system may include frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (Code Division). Multiple Access (CDMA), Universal Mobile Telecommunications Systems (UMTS) (especially Long Term Evolution (LTE)), Global System for Mobile Communications (GSM), etc. May be included. Hereinafter, for convenience of description, the description will be limited to CDMA. However, it is a matter of course that the present invention is applicable to all communication systems including the CDMA wireless communication system.

As shown in FIG. 4, the CDMA wireless communication system includes a plurality of terminals 100, a plurality of base stations (BS) 270, and base station controllers (BSCs) 275. ), And a mobile switching center (MSC) 280. The MSC 280 is configured to be connected to a public switched telephone network (PSTN) 290 and is also configured to be connected to BSCs 275. The BSCs 275 may be coupled to the BS 270 through a backhaul line. The backhaul line may be provided according to at least one of E1 / T1, ATM, IP, PPP, Frame Relay, HDSL, ADSL, or xDSL. Thus, a plurality of BSCs 275 may be included in the system shown in FIG.

Each BS 270 may include at least one sector, and each sector may include an omnidirectional antenna or an antenna pointing radially out of BS 270. In addition, each sector may include two or more antennas of various types. Each BS 270 may be configured to support a plurality of frequency assignments, each of which has a specific spectrum (eg, 1.25 MHz, 5 MHz, etc.).

The intersection of sectors and frequency assignments may be called a CDMA channel. BS 270 may be referred to as a base station transceiver subsystem ('BTSs'). In this case, the word "base station" may be called the sum of one BSC 275 and at least one BS 270. The base station may also indicate “cell site”. Alternatively, each of the plurality of sectors for a particular BS 270 may be called a plurality of cell sites.

As shown in FIG. 4, a broadcasting transmitter (BT) 295 transmits a broadcast signal to terminals 100 operating in the system. The broadcast receiving module 111 shown in FIG. 1 is provided in the terminal 100 to receive a broadcast signal transmitted by the BT 295.

In addition, FIG. 4 illustrates multiple satellite positioning systems (GPS) satellites 300. The satellites 300 help to locate the at least one terminal of the plurality of terminals 100. Although two satellites are shown in FIG. 4, useful location information may be obtained by two or less or more satellites. The location information module 115 shown in FIG. 1 cooperates with the satellites 300 to obtain desired location information. Here, the location can be tracked using all the techniques that can track the location, not just the GPS tracking technology. In addition, at least one of the GPS satellites 300 may optionally or additionally be responsible for satellite DMB transmission.

During typical operation of a wireless communication system, BS 270 receives a reverse link signal from various terminals 100. At this time, the terminals 100 are connecting a call, transmitting or receiving a message, or performing another communication operation. Each of the reverse link signals received by a particular base station 270 is processed within by the particular base station 270. The data generated as a result of the processing is transmitted to the connected BSC 275. BSC 275 provides call resource allocation and mobility management functionality, including the organization of soft handoffs between base stations 270. In addition, the BSC 275 transmits the received data to the MSC 280, and the MSC 280 provides an additional transmission service for connection with the PSTN 290. Similarly, PSTN 290 connects with MSC 280, MSC 280 connects with BSCs 275, and BSCs 275 send BSs 270 to transmit a forward link signal to terminals 100. ).

The present invention proposes a method for acquiring reference time information necessary for obtaining synchronization when heterogeneous network handover occurs in a mobile terminal supporting dual mode.

That is, the present invention obtains the system time in advance from a heterogeneous network (eg, CDMA) modem to be handed over at power-on, and if the handover occurs from the first network to the second network, the system time obtained in advance from the heterogeneous network modem is obtained. By camping on the second network, it is possible to efficiently synchronize the cells of the second network in a short time. The first network is an LTE network, and the second network is a CDMA network.

To this end, the connection manager periodically transmits a sync request message to a heterogeneous network (eg, CDMA) modem to be handed over when the mobile terminal is powered on, and the heterogeneous network modem transmits the synchronization request. Synchronize according to the (Sync request) message and obtain the system time.

5 is a schematic configuration diagram of a mobile terminal having a dual mode function applied to the present invention.

As shown in FIG. 5, the mobile terminal having the dual mode function applied to the present invention is basically the same as the mobile terminal 100 shown in FIG. 1, and has an application processor 50, an LTE modem 51, and a CDMA. Includes a modem 52.

The application processor 50 is provided in the controller 180 to control operations of the LTE modem 51 and the CDMA modem 52 according to a mode setting, and performs various applications. The application processor 50 manages the handover command transmission and the timer to periodically generate a synchronization request signal (Connection Manager (CM)), under the control of the connection manager LTE modem 51 and the CDMA modem ( 52 and an LTE driver and a CDMA driver, respectively. In particular, the connection manager periodically outputs a synchronization request signal to the CDMA modem 52 through the CDMA driver.

The application processor 50 includes a UI / application and a protocol stack. Here, the radio access interface protocol of the application processor 50 is divided into a control plane for transmitting control signals and a user plane for transmitting data information. The user plane is an area in which traffic information of a user is transmitted, such as voice or IP packet transmission, and the control plane is an area in which control information for pausing and managing an interface or a call of a network is transmitted. Thus, UI / applications, protocol stacks and connection managers are included in the control plane, and LTE drivers and CDMA drivers are included in the user plane.

The LTE modem 50 accesses the LTE network under the control of the application processor 50 and performs a cell selection procedure. When the handover is determined by the network, the LTE modem 50 issues a handover command to the application processor 50. Occurs. In this case, a network (LTE network or CDMA network) that preferentially performs the cell selection is determined by user selection. In the present invention, an LTE network will be described as an example for convenience of description.

The CDMA modem 52 obtains the system time according to the synchronization request signal input from the application processor 50 at a predetermined period, and when the handover command is transmitted through the application processor 50, the acquired system time is used. Gain motivation.

6 is a network structure in which a mobile terminal having a dual mode function applied to the present invention is used, and a LTE network serving as a hot spot in a CDMA network is mixed. When the terminal user moves in the network structure and moves from the LTE network to the CDMA network to generate a handover (inter-RAT handover), the mobile terminal searches for a cell to camp on and synchronizes with the CDMA network. .

As described above, an operation of acquiring synchronization by acquiring system time during handover in a mobile terminal having a dual mode function will be described.

7 is a signal flow diagram illustrating an example of a conventional synchronization acquisition method in a dual mode mobile terminal.

Referring to FIG. 7, when the mobile terminal is powered on, the connection manager of the application processor 50 outputs a power-on signal (S10) to connect the LTE modem 50 and the CDMA modem 51 to different communication networks. To operate.

When both the LTE modem 50 and the CDMA modem 51 are operated and the menu setting is set as the LTE preference, the LTE modem 51 performs a cell selection procedure according to the control of the access manager to perform an appropriate cell. Find and then camp on (camp on) the cell (S11). At this time, since the CDMA modem 52 is not awake, no action occurs on the CDMA side.

That is, when the user first turns on the power of the mobile terminal, the controller 180 of the mobile terminal first searches for an appropriate cell and then stays idle in the cell.

When the mobile terminal which is in the dormant state needs to establish an RRC connection with the network, the mobile terminal transitions to the RRC connection state by establishing an RRC connection with the network through an RRC connection procedure. There are several cases in which an idle terminal needs to establish an RRC connection. For example, when an upstream data transmission is necessary due to a user's call attempt or a paging message is received from the network, a response message is transmitted. Etc. can be mentioned.

In order to establish an RRC connection with the network, the idle terminal should proceed with an RRC connection procedure as described above. The RRC connection process is largely performed by the LTE modem 51 transmitting an RRC connection request message to a network (eg, UTRAN), and in response, an RRC connection setup message from the network to the LTE modem 51. And then, the LTE modem 51 is a step of transmitting a RRC connection setup complete (RRC connection setup complete) message to the network.

The wireless connection is established between the mobile terminal and the network by the RRC connection process, and the mobile terminal becomes active (S12).

Subsequently, when a handover (Inter-RAT Handover) is determined by the network as a user of the mobile terminal moves to a new cell (S13), the LTE modem 51 outputs a handover command to the access manager (S14). The access manager transmits the corresponding handover command to the CDMA modem 52 in the mobile terminal (S15).

When the handover command is input, the CDMA modem 52 searches all of the CDMA pilot pseudo random noise sequence (PN) -offsets within the corresponding interval, so that the pilot PN-offset having the strongest auto-correlation characteristic is obtained. If the synchronization is matched, the system time of the CDMA can be found in the synchronization channel (S16). In addition, the CDMA modem 52 transmits the found system time to the connection manager (S17).

Therefore, the CDMA modem 52 synchronizes the call of the CDMA network using the corresponding system time, and thus the user can continue the call without interruption even during handover.

However, the conventional synchronization acquisition method shown in FIG. 7 generally takes a few seconds to about 10 seconds to find the strongest pilot PN-offset, resulting in a delay in obtaining system time.

8 is a signal flow diagram illustrating another example of a conventional synchronization acquisition method in a dual mode mobile terminal.

As shown in FIG. 8, when the mobile terminal is powered on, the connection manager in the application processor 50 outputs a power-on signal to the LTE modem 50 and the CDMA modem 51, respectively. And operating the CDMA modem 51 (S20).

When the menu setting is the LTE preference in the active state, the LTE modem 51 performs a cell selection procedure under the control of the access manager as in FIG. 6 to find an appropriate cell and then camps on the cell. on) (S21, S22). At this time, in the case of LTE preference, when the LTE signal is strong, the LTE modem 51 is operated first, and since the CDMA modem 52 is not currently awake, no action occurs on the CDMA side.

Then, when the user is moved and the handover (Inter-RAT Handover) is determined by the network (S23), LTE modem 51 by using the system information block 8 (SIB8) or dedicated message (dedicated message) through the interface The system time is transmitted to the CDMA modem 52 (S24, S25). That is, the LTE modem 51 outputs a handover command including system time to the access manager, and the connection manager transmits a handover command including system time to the CDMA modem 52 through an interface.

However, the delay caused by API message traffic (status related to power control) or remote procedure call of the interface (eg SDIO) between the LTE modem 51 and the CDMA modem 52 is constant. It may not be deterministic. As a result, the system time used in the LTE modem 51 is not updated correctly with the system time used in the CDMA modem 52.

Therefore, when the handover command including the system time is transmitted, the CDMA modem 52 performs a correction procedure for correcting to the target system time. When the system time is corrected, the CDMA modem 52 synchronizes the call of the CDMA network by using the system time, so that the user can continue the call seamlessly even during handover.

The synchronization acquisition method shown in FIG. 8 provides a system time from the LTE modem 51 to the CDMA modem 52 before the handover so that the CDMA modem can be used when the handover occurs. In this case, the two modems are used. It takes time to compensate for the time delay that occurs at the interface between them.

9 is a signal flow diagram illustrating an example of a synchronization acquisition method of a mobile terminal according to an embodiment of the present invention.

As shown in FIG. 6, when the mobile terminal is powered on, the connection manager in the application processor 50 outputs a power-on signal to the LTE modem 50 and the CDMA modem 51, respectively. The LTE modem 50 and the CDMA modem 51 are operated (S30).

If the menu setting is the LTE preference in the active state, the LTE modem 51 performs a cell selection procedure according to the control of the access manager to find an appropriate cell, and then accesses the network of the corresponding cell to perform a call setup operation. (Active state) (S31, S32). At this time, the access controller drives a timer and transmits a synchronization request signal (or message) to the CDMA modem 52 to start synchronization with the CDMA network at predetermined intervals (S33).

In response to the synchronization request signal, the CDMA modem 52 searches for all CDMA pilot pseudo random noise sequence (PN) -offsets within a corresponding interval, so that the pilot PN-offset having the strongest auto-correlation characteristic is obtained. It finds and synchronizes with the CDMA network, and once synchronized, the system time of the CDMA can be found in the synchronization channel (S34). Once the system time is obtained, the CDMA modem 52 outputs the synchronization completion signal (or message) to the connection manager so that the synchronization request signal (or message) is no longer transmitted.

That is, in the present invention, while the LTE modem 51 first accesses the LTE network and performs a procedure of camping on a suitable cell through a call selection procedure, the CDMA modem 52 is connected to the access manager. As soon as it receives the synchronization request signal (or message) transmitted periodically, it acquires the system time by synchronizing with the CDMA network.

After the user is moved to determine the handover (Inter-RAT Handover) by the network (S36), LTE modem 51 outputs a handover command to the access manager (S37), the connection manager is a corresponding handover command Is transmitted to the CDMA modem 52 in the mobile terminal (S38).

When the handover command is input from the LTE modem 51, the CDMA modem 52 can use the system time obtained in the step S34 as it is so that it can efficiently synchronize with the call of the CDMA network in a short time without correction process. do.

As described above, the present invention actually obtains the system time by synchronizing with the CDMA network in the CDMA modem while the LTE modem accesses the LTE network and performs the call selection procedure in the LTE preference environment. System time can be used to synchronize the call of the CDMA network.

In addition, the present invention has been described using the case of handover from the LTE network to the CDMA network as an example for convenience of description, but the present invention is not limited thereto. The same applies to the case of handover from the CDMA network to the LTE network.

Therefore, the present invention can reduce the handover delay caused when obtaining the system time in the modem to move in the conventional handover, and transfer the system time from the LTE modem (or CDMA modem) to the CDMA modem (or LTE modem). In this case, it is possible to reduce the overall synchronization time by eliminating the correction procedure that occurs.

In addition, according to an embodiment of the present invention, the above-described method may be embodied as computer readable codes on a medium in which a program is recorded. The computer-readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the computer-readable medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and also implemented in the form of a carrier wave (for example, transmission over the Internet) . The computer may also include a control unit of the terminal.

The above-described mobile terminal is not limited to the configuration and method of the above-described embodiments, but the embodiments may be configured by selectively combining all or some of the embodiments so that various modifications can be made. It may be.

1 is a block diagram of a mobile terminal according to one embodiment of the present invention;

2 is a front perspective view of a mobile terminal according to an embodiment of the present invention;

3 is a rear perspective view of a mobile terminal according to one embodiment of the present invention;

4 is a block diagram of a wireless communication system in which a mobile terminal according to an embodiment of the present invention may operate.

5 is a schematic configuration diagram of a mobile terminal having a dual mode function applied to the present invention.

6 is a diagram illustrating a network structure in which a mobile terminal according to the present invention is used.

7 is a signal flow diagram illustrating an example of a general synchronization acquisition method.

8 is a signal flow diagram illustrating another example of a general synchronization acquisition method.

9 is a signal flow diagram illustrating an example of a synchronization acquisition method of a mobile terminal according to an embodiment of the present invention;

******* Description of the symbols for the main parts of the drawing ********

110: wireless communication unit 111: broadcast receiving module

112: mobile communication module 113; Wireless Internet Module

140; Sensing unit 150: output unit

151: display unit 160: memory

180: control unit

Claims (13)

Performing a cell selection by connecting the first modem to the first network when the power is turned on; Acquiring a system time in synchronization with a second network in a second modem while performing cell selection of the first modem; When a handover occurs from the first network to a second network, transmitting a handover command from the first modem to a second modem; And synchronizing a call of a second network using the system time obtained by the second modem according to the handover command. The method of claim 1, wherein the first and second networks A heterogeneous network, wherein the first network is an LTE network and the second network is a CDMA network. The method of claim 1, wherein the first and second networks A heterogeneous network, wherein the first network is a CDMA network and the second network is an LTE network. The network of claim 1, wherein the network that preferentially performs the cell selection A method for acquiring synchronization of a mobile terminal, characterized in that determined by user selection. The method of claim 1 wherein the handover is Method for acquiring synchronization of a mobile terminal, characterized in that inter-RAT handover. The method of claim 1, wherein the second modem And receiving a synchronization request signal periodically to obtain synchronization with the second network when the power is turned on. A first modem connecting to the first network and performing cell selection when the power is turned on; A connection manager for periodically generating a synchronization request signal; While performing the cell selection of the first modem, the system time is acquired in synchronization with the second network according to the synchronization request signal, and when the handover from the first network to the second network occurs, the acquired system time A mobile terminal comprising a second modem for synchronizing to a call of the second network by using. The method of claim 7, wherein the first and second network A heterogeneous network, wherein the first network is an LTE network and the second network is a CDMA network. The method of claim 7, wherein the first and second network A heterogeneous network, wherein the first network is a CDMA network and the second network is an LTE network. 8. The network of claim 7, wherein the network that preferentially performs the cell selection A mobile terminal characterized in that determined by the user selection. 8. The method of claim 7, wherein the handover is A mobile terminal characterized by inter-RAT handover. The method of claim 7, wherein the connection manager And generating a sync request signal periodically upon power-on, and stopping the generation of the sync request signal when the sync completion signal is input from the second modem. The method of claim 7, wherein the second modem And obtaining the system time before the handover occurs.

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