KR20140146820A - Apparatus and method for proceeding rradio access technoligy in wireless communication system - Google Patents

Abstract

The present invention relates to a wireless communication system, and more specifically, to an apparatus and a method for wireless multiple access for efficiently supporting a request service of a terminal in a wireless communication system. The present invention includes an operation for combining wireless access networks (RATs) accessible by a terminal and all frequency bands of each RAT to allocate scanning priority indexes for preferentially performing frequency scanning, and determining scanning validity for a corresponding index to select a PLMN. Accordingly, at the time of PLMN selection by the terminal, power consumption of a terminal is minimized by performing selective scanning operation and selectively controlling a searching range for the PLMN selection. Through this, efficiency for the PLMN selection by the terminal is provided.

Description

[0001] APPARATUS AND METHOD FOR PROCESSING RRADIO ACCESS TECHNOLOGY IN WIRELESS COMMUNICATION SYSTEM [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system, and more particularly, to a wireless connection apparatus and method for efficiently supporting a requested service of a terminal in a wireless communication system in which one or more wireless connections coexist.

Recently, LTE (Long Term Evolution) system, a next generation wireless communication system, has been commercialized in earnest. This LTE system is spreading more rapidly after recognizing the need to support high-quality services for voice services as well as high-capacity services for users' needs while ensuring the activity of terminal users. The LTE system provides low transmission delay, high data rate, system capacity and coverage improvement.

On the other hand, considering the needs of service providers providing services to users, LTE system can improve performance by improving existing radio access and network, (Universal Mobile Telecommunication System) based on a 2G communication system and a Wideband Code Division Multiple Access (W-CDMA) system, which are GSM (Global System for Mobile Communications) And is compatible with 3G communication systems and is being developed into a coexistence mode. For example, LTE systems that support packet-based services offer more than 5 times higher data rates than existing wireless communication systems due to their flexibility and efficiency based on IP. There is an evaluation that the service quality is insufficient as compared with the voice service in the existing circuit domain.

Therefore, there is a need for an efficient wireless connection to an appropriate network in order to satisfy a user's demand in a wireless communication system in which different wireless communication systems coexist. In particular, there is a need for a radio access technology for minimizing battery power consumption of a terminal having a limited capacity.

SUMMARY OF THE INVENTION The present invention provides a wireless access apparatus and method for efficiently supporting a requested service of a multi-access terminal in a wireless communication system.

It is another object of the present invention to provide an apparatus and method for determining a scanning order by combining multiple wireless access networks (RATs) and bands of each network in a wireless communication system.

It is another object of the present invention to provide a frequency scanning apparatus and method for selecting a network of a terminal supporting multiple wireless access in a wireless communication system.

It is another object of the present invention to provide an apparatus and method for selecting a network according to frequency scanning that minimizes power consumption of a terminal supporting multiple wireless connections.

According to an aspect of the present invention, there is provided a method of performing multiple radio access in a wireless communication system, the method comprising: combining radio access networks (RAT) supported by the terminal with frequency bands supporting services in each RAT Determining validity for scanning in the order of network identification information (PLMN) having the highest priority according to a priority for performing the determined scanning; And performing a wireless connection to at least one PLMN selected in consideration of the validity of the PLMN.

According to another aspect of the present invention, there is provided a terminal apparatus for performing multiple wireless connections in a wireless communication system, the terminal apparatus comprising: a wireless processing unit for transmitting and receiving a wireless signal; and a wireless processing unit connected to the wireless processing unit, (RATs) and frequency bands supporting services in respective RATs, determines a priority for performing scanning, and determines network identification information having the highest priority according to a priority for performing the determined scanning PLMN) in order, and performs wireless connection with at least one PLMN selected in consideration of the confirmed validity.

The present invention has an advantage of providing a frequency scanning scheme that minimizes power consumption in cell reselection of a UE in a wireless communication environment in which different wireless communication systems coexist. Accordingly, it is advantageous for a terminal having a limited battery capacity to minimize battery consumption in a multi-radio connection. In addition, since it is unnecessary to perform scanning for an unnecessary frequency, it is possible to support wireless connection from the terminal to the network more quickly, and it also provides an advantage of maximizing the service of the user.

1 is a diagram schematically illustrating a structure of a next generation wireless communication system to which the present invention is applied.
2 is a block diagram illustrating a radio protocol architecture for a user plane to which the present invention is applied.
3 is a block diagram illustrating a wireless protocol structure for a control plane to which the present invention is applied.
4 is a diagram schematically illustrating a radio access procedure of a terminal supporting multiple access in a wireless communication system to which the present invention is applied.
5 is a schematic diagram illustrating a procedure for performing multiple wireless connections according to an embodiment of the present invention.
6 is a diagram illustrating an operation of a UE for performing cell reselection according to a scanning scheme through a priority according to an embodiment of the present invention.
7 is a diagram illustrating operations of a terminal for verifying the validity of scanning according to an embodiment of the present invention.
8 is a block diagram briefly showing a structure of a terminal according to the present invention.

Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

The present invention will be described with reference to a communication network. The work performed in the communication network may be performed in a process of controlling the network and transmitting data by a system (e.g., a base station) that manages the communication network, The work can be done.

1 is a schematic view illustrating a structure of a next generation wireless communication system to which the present invention is applied. This discloses the network structure of an E-UMTS (Evolved-Universal Mobile Telecommunications System). The E-UMTS system is called a LTE (Long Term Evolution) or LTE-A (advanced) system and is a packet-based system for providing various communication services such as voice and packet data.

Referring to FIG. 1, an E-UTRAN includes a base station 20 (eNB) that provides a control plane and a user plane to a user equipment (UE) 10. The terminal 10 may be fixed or mobile and may be referred to by other terms such as a mobile station (MS), an advanced MS (MS), a user terminal (UT), a subscriber station (SS) .

The base station 20 generally refers to a station that communicates with the terminal 10 and includes a base station (BS), a base transceiver system (BTS), an access point, a femto-eNB, A pico-eNB, a home eNB, a relay, or the like. The base station 20 can provide services to the terminal through at least one cell. The cell may mean a geographical area where the base station 20 provides communication services, or may refer to a specific frequency band. A cell may denote a downlink frequency resource and an uplink frequency resource. Or a cell may mean a combination of a downlink frequency resource and an optional uplink frequency resource. In this regard, in the LTE system, it is possible to provide an effect similar to the use of one large band band logically by bundling a plurality of physically continuous or non-continuous bands in the frequency domain, To provide high data rate.

The base stations 20 may be interconnected via an X2 interface. The base station 20 is connected to an S-GW (Serving Gateway) through an MME (Mobility Management Entity) and an S1-U through an EPC (Evolved Packet Core) 30, more specifically, an S1-MME through an S1 interface. The S1 interface exchanges OAM (Operation and Management) information to support the movement of the terminal 10 by exchanging signals with the MME.

The EPC 30 includes an MME, an S-GW, and a Packet Data Network-Gateway (P-GW). The MME has information on the connection information of the terminal 10 and the capability of the terminal 10. This information is mainly used for managing the mobility of the terminal 10. [ The S-GW is a gateway having an E-UTRAN as an end point, and the P-GW is a gateway having a PDN (Packet Data Network) as an end point.

The E-UTRAN and the EPC 30 may be combined to form an EPS (Evolved Packet System), and the traffic flow from the wireless link to the base station 20 to the PDN connecting the terminal 10 to the service entity (Internet Protocol).

The wireless interface between the terminal and the base station is called a Uu interface. The layers of the radio interface protocol between the UE and the network are classified into L1 (first layer), L1 (second layer), and the like based on the lower three layers of the Open System Interconnection (OSI) A physical layer belonging to a first layer provides an information transfer service using a physical channel, and a physical layer (physical layer) An RRC (Radio Resource Control) layer located at Layer 3 controls the radio resources between the UE and the network. To this end, the RRC layer exchanges RRC messages between the UE and the BS.

2 is a block diagram illustrating a radio protocol architecture for a user plane. 3 is a block diagram illustrating a wireless protocol structure for a control plane. The user plane is a protocol stack for transmitting user data, and the control plane is a protocol stack for transmitting control signals.

2 and 3, a physical layer (PHY) layer 210 provides an information transfer service to an upper layer using a physical channel. The physical layer is connected to a medium access control (MAC) layer, which is an upper layer, through a transport channel. Data is transferred between the MAC layer and the physical layer through the transport channel. The transport channel is classified according to how the data is transmitted through the air interface. Data is transferred between the different physical layers, that is, between the transmitter and the physical layer of the receiver through a physical channel. The physical channel can be modulated by an Orthogonal Frequency Division Multiplexing (OFDM) scheme, and uses time and frequency as radio resources. There are several physical control channels. The physical downlink control channel (PDCCH) informs the UE of resource allocation of a paging channel (PCH), a downlink shared channel (DL-SCH), and hybrid automatic repeat request (HARQ) information related to the DL-SCH. The PDCCH may carry an uplink scheduling grant informing the UE of the resource allocation of the uplink transmission. A physical control format indicator channel (PCFICH) informs the UE of the number of OFDM symbols used for PDCCHs and is transmitted every subframe. PHICH (Physical Hybrid ARQ Indicator Channel) carries HARQ ACK / NAK signal in response to uplink transmission. A physical uplink control channel (PUCCH) carries uplink control information such as HARQ ACK / NAK, scheduling request and CQI for downlink transmission. A physical uplink shared channel (PUSCH) carries an uplink shared channel (UL-SCH).

The function of the MAC layer 220 is to perform mapping / demultiplexing to a transport block provided on a physical channel on a transport channel of a MAC SDU (service data unit) belonging to a logical channel and a mapping between a logical channel and a transport channel . The MAC layer provides a service to a Radio Link Control (RLC) layer through a logical channel. The logical channel can be divided into a control channel for transferring control area information and a traffic channel for transferring user area information.

The function of the RLC layer 230 includes concatenation, segmentation and reassembly of the RLC SDUs. In order to guarantee various QoS (Quality of Service) required by a radio bearer (RB), the RLC layer includes Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode , And AM). AM RLC provides error correction via automatic repeat request (ARQ).

The functions of the Packet Data Convergence Protocol (PDCP) layer 240 in the user plane include transmission of user data, header compression and ciphering. The function of the Packet Data Convergence Protocol (PDCP) layer in the user plane includes transmission of control plane data and encryption / integrity protection.

The RRC layer 250 of FIG. 3 performs functions such as broadcast, paging, RRC connection management, RB control, mobility, and UE measurement of system information related to the NAS / AS. In particular, temporary ID assignment and radio resource setting for RRC connection are performed for setting up, managing, and releasing RRC connection between UE and E-UTRAN. That is, it is responsible for the control of the logical channels, the transport channels and the physical channels in connection with the configuration, re-configuration and release of the RBs. RB means a logical path provided by a first layer (PHY layer) and a second layer (MAC layer, RLC layer, PDCP layer) for data transmission between a UE and a network. The configuration of the RB means a process of defining characteristics of a radio protocol layer and a channel to provide a specific service, and setting each specific parameter and an operation method. The RB may be further classified into an SRB (Signaling RB) and a DRB (Data RB). The SRB is used as a path for transmitting the RRC message and the NAS message in the control plane, and the DRB is used as a path for transmitting the user data in the user plane.

In addition, the RRC layer 250 may perform mobility measurement between UEs and RAT (Radio Access Technology), UE handover, UE cell selection and reselection, context transmission between eNBs, UE measurement report, .

The NAS (Non-Access Stratum) layer located at the top of the RRC layer performs functions such as session management and mobility management.

When there is an RRC connection between the RRC layer of the UE and the RRC layer of the E-UTRAN, the UE is in an RRC connected state. Otherwise, the UE is in an RRC idle state do.

Meanwhile, the present invention provides an enhanced packet system (EPS) service in consideration of services of a terminal in a wireless communication system in which an access network supporting the next generation wireless communication and an access network supporting 2G / 3G wireless communication coexist (Non-EPS) service. Here, a concrete operation of a specific terminal performing cell selection to a network supporting a packet service or a network supporting a non-packet service And more particularly, to a cell selection method for minimizing battery consumption of a terminal.

4 is a diagram schematically illustrating a procedure for supporting a requested service of a terminal in a wireless communication system including various radio access networks to which the present invention is applied.

Referring to FIG. 4, the terminal 400 is a terminal supporting Multi-Radio Access Technology (hereinafter referred to as 'Multi-RAT' or 'Multiple Access Mode'). The UE supporting the Multi-RAT includes the E-UTRAN 410, the GERAN (Global System for Mobile Communications) / EDGE (Enhanced Data Rates for GSM Evolution) radio access network / UTRAN The terminal 400 is connected to the Terrestrial Radio Access Network 430 and can support the EPS service provided in the packet domain and the non EPS provided in the circuit domain. The terminal 400 is currently located in the E-UTRAN 410 .

The terminal 400 registers with the MME 420 that manages the mobility of the terminal to support EPS (hereinafter, used in combination with 'packet') / non-EPS Request message (Attach Request, 450). The registration request message includes EPS / non-EPS registration request information, which is information on whether the terminal 400 supports the packet / non-packet service. Also, the registration request message is performed through a combined access procedure, and the terminal 400 attempts to register its location in the MME 420.

Here, the MME 420 is an evolved packet core (EPC) network, and includes NAS signaling (NAS signaling), AS security control (AS signaling), and mobility control (UE in idle and active mode), SGSN selection for handover to a 2G / 3G access network, roaming, and the like. That is, the MME 420 controls a wireless link and a wired link, and controls the terminal 400 to access a network of another communication system or a network under the network management of the corresponding system. 400) and control functions necessary for efficient operation of frequency resources.

When the MME 420 confirms that there is a problem in the terminal 400 regarding the provision of the EPS service, the MME 420 transmits a registration rejection request including an EPS mobility management (EMM) ATTACH REJECT, 460) message to the terminal 400. In the present invention, the registration rejection message will be described as '# 7 EPS Service not allowed', which means that the EPS service is not authorized. Accordingly, the terminal 400 can not support the EPS service of the terminal 400 through the registration rejection message transmitted from the MME 420, and recognizes that the location registration in the MME 420 fails. This confirms that any operation for providing the EPS service is impossible using the current USIM installed in the terminal 400. [

Meanwhile, the terminal 400 selects an access network other than the E-UTRAN 410 (Inter-RAT Reselection) as a multi-RAT terminal and transmits a non-EPS service in addition to the EPS service It is a UE that can support. The UE 400 selects a cell (re-selection) from the GERAN (or UTRAN) 430 through a measurement procedure and then transmits a location update message to the Mobile Switching Center (MSC) Update, 480) request message. The MSC 430 notifies the location registration to the terminal 400 is successfully performed for the non-EPS service through a LOCATION UPDATING ACCEPT message. Therefore, the terminal 400 performs wireless connection to one (selected) cell 430 of the GERAN and the UTRAN, and supports the non-EPS service through the wireless connection.

In step 460, to support the EPS service, the terminal 400 that is not allowed to support the EPS service may turn off the power of the terminal to newly start the wireless setting procedure with the E-UTRAN, There is a restriction to remove a Universal Subscriber Identity Module (USIM) mounted on the terminal.

In this manner, after the terminal is powered off and booted up, the terminal can perform service recovery in a shadow area and a limited service area in order to receive a service provided from the network To perform, a PLMN selection procedure is performed. This is an operation for searching for a PLMN (Public Land Mobile Network (PLMN)) that is a service provider network identification number capable of being served by a terminal. For this purpose, the terminal searches all RATs supported by the terminal, Frequency scanning is performed on all the bands supported by the mobile station.

However, as described above, in recent wireless communications, not only the types of wireless access networks that can be accessed by terminals due to the commercialization of LTE technology as well as GSM and WCDMA have increased, As the frequency band used to satisfy the demand increases, the terminal needs more time and power to scan the added RAT and various bands than the existing wireless communication system.

Meanwhile, the issue of battery saving of the terminal is continuously required. Accordingly, the present invention is a method for quickly searching for a network capable of serving a terminal, and defines a priority sequence for performing scanning in a combination of various RATs and bands, and provides an optimized scanning method. In addition, scanning optimization is provided through operations such as the number of scanning times and scanning, and a method for acquiring a fast network service through the optimization is provided. In addition, the present invention proposes a wireless access scheme that maximizes the battery saving of the terminal.

FIG. 5 is a diagram schematically illustrating an operation of a terminal performing multiple wireless connections according to an embodiment of the present invention.

Referring to FIG. 5, the UE 501 is located in the E-UTRAN, the 4G EM Mobility Management 502 is in the active state and the 3G 503 / 2G 504 is in the inactive state (INACTIVE) state. Here, the active state means that the terminal 501 is allocated a radio resource from the current network to receive the service, that is, a radio access (RAT) is performed with the corresponding network. This means that the UE 501 is configured with a radio resource control (RRC) connection with the E-UTRAN.

On the other hand, the 4G EMM 502, which is the active state, indicates an EMM-DEREGEDED_NORMAL state in which the information of the terminal 501 has not yet been registered (ATTACH) in the upper network. That is, there is no information related to the mobility support of the UE 501, that is, there is no UE context related to the mobility. Here, the registration / connection state of the 4G EMM 502 can be transitioned to an idle state or a connected state (Connected) with respect to the mobility of the terminal according to the PLMM cell selection procedure of the terminal 501, It is also related to the state.

The 4G EMM 502 includes a registration procedure (ATTACH) with a procedure related to Global Unique Temporary Identifier (GUTI) assignment, authentication, UE identification, security mode control, and user mobility Update (TAU) procedure. That is, the 4G EMM 502 supports PLMN cell selection to support a service requested by the UE and UE registration process in a specific network supporting the UE to support wireless connection to the UE in the corresponding network.

In the present invention, the terminal sets a scanning priority for performing frequency scanning in consideration of the RAT and the band of each RAT (510). A method of setting the scanning order by combining the RAT / Band of the terminal can be defined by distinguishing a) current position information and b) current position information. Here, the current location information may include country information and the like. The country information may be identified through a mobile country code, which is system information of the network.

a) If the terminal has current location information (country)

1. The RAT / Band used by Registered PLMN (RPLMN)

2. The RAT / Band used by home PLMN (HPLMN)

3. The RAT / Band used by the User controlled PLMN (UPLMN)

4. The RAT / Band used by Operator controlled PLMN (OPLMN)

5. RAT / Band used by country or operator except 1/2/3

6. RAT / Band supported by UE except 1/2/3/4

Herein, the Registered PLMN means a wireless communication network in which the terminal, that is, the subscriber was last wirelessly connected, the Home PLMN means a service provider network subscribed by the user, and the User controlled PLMN means a provider network established by the user Operator controlled PLMN means the network established by the operator.

b) If the terminal does not have current location information (country)

1. RAT / Band used by RPLMN

2. RAT / Band used by HPLMN

3. RAT / Band used by UPLMN

4. RAT / Band used by OPLMN

5. RAT / Band excluding 1/2/3

The reason why the priority is distinguished by information on the current location information (country) is that the terminal can save battery consumption by performing the PLMN search in consideration of the location information. As an example, assume that a terminal user in country A moves to country B and receives a service through a roaming PLMN. When powering off the local B country and then boosting up, the terminal can minimize the power consumption by registering the Registered PLMN with the highest priority and considering the current location information (country). That is, by saving the power consumed by constantly searching for the subscribed network of country A by prioritizing the registered network of terminal A or country B, which has recently been wirelessly connected, to be.

Table 1 below lists the priorities of scanning for selecting a PLMN as index 1 through index 10, as a result of combining the RAT / Band described above by the terminal. Table 1 shows the scanning information for RAT / band in index units.

Index RAT Band List Searching Priority Time stamp (scanning time) Reference cell ID Validity Quick search info. One EUTRAN Band 1 One One One V #One 2 Band 2 2 One 2 IN-V #2 3 Band 3 3 3 3 IN-V # 3 4 UTRAN Band 1 4 3 4 IN-V # 33 5 Band 4 5 3 5 V # 35 6 Band 7 6 5 6 IN-V # 37 7 GERAN 850 7 5 7 IN-V 5 8 900 8 5 8 V 5 9 1800 9 3 IN-V 3 10 1900 10 One IN-V One

The scanning priority according to the present invention includes time stamp, reference cell information,? Search information, validity information on previous scanning, and the like. Here, the time stamp (scanning time) refers to the local time in which the RAT / Band is searched. The time unit is s (second), min (minute) μs). In addition, the information on the reference cell may be cell unique identification information for distinguishing cells of the network, and may use a global cell ID. Also, each network may use a UTRFCN (UTRA Absolute Radio Frequency Channel Number) or EARFCN (E-UTRA Absolute Radio Frequency Channel Number) or a center frequency of the corresponding frequency as a value for distinguishing between the frequency bands supported by the network have. In addition, it may include a cell ID (Physical Cell ID) used to distinguish the corresponding cell in the physical layer.

In the UARFCN, the uplink and the downlink are distinguished from each other, and the range of 0.0 MHz? F _{uplink ( or downlink)} ? 3276.6 MHz N _{u / d} = 5 * F _{uplink ( or downlink} < / RTI >

E-UTRA Operating Band Uplink (UL) operating band
BS receive
UE transmit Downlink (DL) operating band
BS transmit
UE receive Duplex Mode F _{UL _ low} - F _{UL _ high F DL _ low - F UDL _} high One 1920 MHz 1980 MHz 2110 MHz 2170 MHz FDD 2 1850 MHz 1910 MHz 1930 MHz 1990 MHz FDD 3 1710 MHz 1785 MHz 1805 MHz 1880 MHz FDD ... 33 1900 MHz 1920 MHz 1900 MHz 1920 MHz TDD 34 2010 MHz 2025 MHz 2010 MHz 2025 MHz TDD 35 1850 MHz 1910 MHz 1850 MHz 1910 MHz TDD

The quick search info is information required to search for a specific cell in the physical layer. The matching information includes timing information (time info) required to search the cell or time information And the like may be applied. The validity information is information for examining the validity of the index before performing the RAT / Band search, indicating that the corresponding index has been previously searched for, and may also be referred to as &quot; It may indicate that it is an object. Or to determine the validity for the current search, and may be newly determined information. Therefore, the priority may be set reflecting the validity information according to the validity check result of the index.

Accordingly, when performing the PLMN selection, the UE determines a priority for scanning according to the scanning order setting of the RAT / Band combination, and assigns a high priority index (RPLMN, HPLMN) having a high priority according to the priority (510). In the low priority index having a low priority, the time required for selecting the entire PLMN can be shortened by selecting the corresponding PLMN without performing scanning if necessary.

The terminal stores information on the confirmed PLMNs in consideration of the scanning priority (520). Information on the PLMNs may be stored in a PLMN list format as shown in Table 3 below.

PLMN List RAT (u / e) ArFcN Cell ID Time stamp (last measurement time) Access restriction PLMNE UTRAN # 35 # 5 3 Forbidden PLMNE EUTRAN #One #One One PLMN B GERAN 5 #8 5

Using the PLMN list, the UE 501 can select a corresponding PLMN to perform a wireless connection in consideration of a service requested by a user. That is, in step 530, a wireless connection may be attempted to the corresponding network using the information on the PLMNs identified through the priority order. In the present invention, an attempt is made to register the location with the PLMN A having the highest priority according to the scanning priority. Here, the PMMN A is a cell capable of supporting both the EPS / non-EPS service, but the wireless connection for supporting the actual non-packet service is limited.

The UE 501 transmits an ATTACH REQUEST message to the MME 509 to request the E-UTRAN wireless connection. Table 4 below is an example of terminal related information that can be included in the registration request message.

<UE related Information>
EPS capability: Enabled
Supported RAT: E-UTRAN, GERAN, UTRAN
UE supports EPS / non-EPS service

Meanwhile, the MME 509 records and tracks the authentication, security, and mobility of the terminal 501 with respect to the wireless access to the terminal, thereby determining a registration request. At this time, the service of the terminal can be restricted or rejected using the charging information of the terminal 501 or the like. At this time, the MME 509 confirms that the EPS service support is impossible in the currently allocated E-UTRAN, and notifies the terminal 501 of the ATTACH REJECT message (540).

The UE 501 may periodically perform the scanning operations of the 510 and 520 for the PLMN reselection. In addition, the PLMN selection procedure can be controlled by reflecting periodically performed results in Table 1.

In this case, considering the RAT / Band scanning information maintenance / management, a reference cell for each RAT / Band index is set during PLMN selection, and a periodically retried PLMN selection Is performed through a "Target RAT / Band-specific scanning validity check" using a timer.

c) Set the reference cell by RAT / Band

1. When there is a serving cell during the RAT / Band scanning; Set serving cell as reference cell

2. When there is no serving cell during the RAT / Band scanning;

If the strongest cell in scanning is larger than P_min, it is set as a reference cell. If there is no cell found during scanning, a cell found within T_min among reference cells set in another RAT / Band is set as a reference cell Set

Herein, P_min is a minimum value at which the corresponding cell is determined to be valid by a measured power of a specific cell, and a measurement quantity and a measurement result may be different depending on multiple connections . T_min is the maximum time that it is determined that iterative scanning is not needed for a specific time in the index unit immediately after the scanning, and T_max is the minimum time that it is determined that repetitive scanning is required after a specific time in units of index immediately after scanning.

d) Target RAT / Band scanning validation setting

1. Valid when the latest scanning time by index (Index) is smaller than T_min.

2. Invalid if the scanning time per index is larger than T_max.

3. When the scanning time per index is larger than T_min and smaller than T_max; If the reference cell is the same as the serving cell and the reference cell is different from the serving cell and the measured power value of the measurement result of the reference cell measured through the quick search is larger than P_min It is set to be valid (valid) and invalid if it is small

Accordingly, the UE reflects the scanning information collected in the PLMN selection procedure performed recently in order to reduce the number of redundant and unnecessary RAT / Band scanning during periodic PLMN selection. In this case, in order to maintain / manage the scanning priority for each index, information on retries of the current cell and information on retries of the target cell are considered. Therefore, the power consumption of the terminal due to the return of the PLMN service can be reduced in a limited service or an out-of-service area. That is, in order to save power of the terminal, redundant or unnecessary RAT / Band scanning is prevented in advance (560).

Meanwhile, the PLMN 505 supports the PLMN selection of the UE through the RAT handover procedure between the networks (552). Accordingly, the PLMN 505 transmits a PLMN selection request message to the RRC 508 of the RRC / UTRAN of the E-UTRAN or the RR 509 of the GSM to check the search result and obtain an initial PLMN (554). In the PLMN selection procedure, a PLMN selection request according to the service needs of the terminal is transmitted to the 4G-RRC layer 506 supporting the EPS service and to the 3G RRC 508 or 2G RR 509 supporting the non-EPS service The PLMN selection procedure is controlled to exist (Step 554).

After that, the UE 501 determines cell reselection from the E-UTRAN 502 where it is located to the GERAN 504 and receives radio resources from the GERAN 504 (570). The terminal then initiates a registration request to the GERAN 504, which is a wireless access network for supporting non-EPS service (580). Accordingly, the 2G 504 that has completed the wireless connection transitions to the active state (ACTIVE), and the 4G EMM 502 / 3G GMM / MM 503 transitions to the inactive state (INACTIVE RAT). The terminal 501 transmits a location update request message to the GERAN 504 to request approval of the service support for supporting the non-EPS service (590).

6 is a diagram illustrating an operation of a UE for performing cell reselection according to a scanning scheme through a priority according to an embodiment of the present invention.

Referring to FIG. 6, in operation 605, the UE determines whether a 3GPP radio access technology supported by the UE is an applied network, GERAN, UTRAN, and EUTRAN, and confirms all frequency bands supported by each RAT. Considering the support of the plurality of RATs and bands, an index is determined, and a priority for scanning is set for each index.

In step 610, the index having the highest priority is selected according to the set scanning priority, and in step 615, it is determined whether the selected index is valid.

If it is determined that the index selected in step 615 is not valid, then in step 620, the corresponding index is scanned and information about one or more PLMNs confirmed through the scanning process is stored. Here, the information about the identified at least one PLMN may be stored in the form of a PLMN list. On the other hand, if it is determined in step 615 that the selected index is valid, the process proceeds to step 625.

In step 625, the existence of the PLMN corresponding to the index is confirmed. At this time, if there are other PLMNs corresponding to the index in step 625, the flow advances to step 630 to check whether the corresponding PLMN is RPLMN or HPLMN. If it is determined that the PLMN is one of RPLMN or HPLMN, the process proceeds to step 635 and attempts to register with the corresponding PLMN. Then, in step 640, it is confirmed whether registration for the PLMN is successful or rejected. If registration is successful, the terminal is wirelessly connected to the network and supports the requested service of the terminal. On the other hand, if registration fails in step 640, the process proceeds to step 645.

On the other hand, if it is determined in step 625 that there is no more PLMN corresponding to the index, the process proceeds to step 645 to select an index having the next priority, and performs the operations of steps 615 to 625 as needed . At this time, the operations of the steps 615 to 645 may be terminated by checking whether all the indexes have been searched for, as shown in step 650.

If all the indexes are scanned in step 650, information on PLMNs that are the result of step 655 is stored. Here, the information about the identified at least one PLMN may be stored in the form of a PLMN list. In step 660, the UE attempts to register the confirmed PLMNs in order of PLMN according to the priority order.

As described above, the terminal performs PLMN selection using the scanning information according to the priority order, and confirms whether the selected PLMN is RPLMN or HPLMN, thereby guiding the power consumption for searching for the terminal to be minimized when the PLMM is selected. Therefore, instead of attempting frequency scanning for all RATs and all bands supported by each RAT, scanning a band of a network supporting a frequency in consideration of priorities, and selecting a final PLMN selection .

Hereinafter, the validity check operation of the index for checking whether the selected index is valid in performing the scanning operation according to the set priorities will be described in more detail. This is to only validate the scanning of the required network frequency, and to check the validity / invalidity of the index.

Accordingly, the UE repeatedly uses the information on T_min, T_max, reference cell, and the like to selectively perform a scanning attempt or scanning exclusion for the corresponding cell when the PLMN is selected. can do. Through the selective scanning process, the UE enjoys the advantage of saving the power and time required for selecting the PLMN.

7 is a diagram illustrating operations of a terminal for verifying the validity of scanning according to an embodiment of the present invention.

Referring to FIG. 7, in step 705, the terminal checks the timestamp of the selected index. That is, it is confirmed whether or not the scanning time for the selected index has exceeded T_max which is a predetermined time, that is, a time at which the scanning is determined to be necessary for the index. If the time stamp exceeds the preset T_max, the process proceeds to step 740 and determines that the index is invalid. Therefore, the scanning is retried corresponding to the index. Therefore, the mobile station scans the frequency corresponding to the index and confirms whether the PLMN is to be selected by considering the scanned result.

On the other hand, if it is determined that the time stamp does not exceed the predetermined T_max, the process proceeds to step 710, where it is determined whether the time stamp is smaller than a predetermined T_min. That is, in step 710, it is determined whether the result of the previous scanning is a value that can be judged as no time-wise additional scanning. Accordingly, if the time stamp is smaller than the T_min, the process proceeds to step 725, and the time stamp is treated as a valid value. Therefore, the processing is performed as a target for PLMN search without performing a separate scanning operation.

On the other hand, if the time stamp is greater than T_min, the process proceeds to step 715 to check the state of the UE. In step 720, the UE confirms whether the camped-on cell is a serving cell. Here, when the terminal is in the camping on state, it means that the PCH / SI can be monitored in the selected cell and the user can perform the monitoring operation and the cell reselection if necessary.

Here, the determination that the current cell is a serving cell means a cell in which the measurement result of the cell is the best and satisfies the interference condition. Accordingly, if the cell selection condition is satisfied according to the measurement result, the process proceeds to step 725 to process the cell, that is, the index having the scanning frequency, as a PLMN target having a valid priority. On the other hand, if the cell is not a serving cell in step 720, the process proceeds to step 740 and determines that the index is invalid.

On the other hand, if the UE not camped on the cell in step 715 determines that the cell corresponding to the index is a? And performs a search. If the measured power of the cell corresponding to the index is greater than P_min, which is a value set for judging the validity, as a result of performing the quick search, the process proceeds to step 735 to determine that it is valid. On the other hand, The process proceeds to step 740 where it is determined that the cell corresponding to the index is invalid.

As described above with reference to FIG. 7, in performing scanning according to the set scanning priority, the terminal determines whether the scanned values are valid by determining the validity in consideration of the result of the previous scanning, that is, Operation and B) a measurement result of a cell corresponding to a frequency at which the scanning is to be performed, and checking whether the corresponding cell is a cell having proper validity for cell selection, thereby maintaining / managing the scanning information, The reliability of the scanning operation is maximized.

In addition, the present invention has an advantage in that selection is made to a suitable PLMN without performing additional scanning for an index having a valid value, and the total time and power consumption required for PLMN selection is saved.

8 is a block diagram briefly showing a structure of a terminal according to the present invention.

Referring to FIG. 8, a terminal 800 includes a radio signal processing unit (RF unit) 810, a processor 820, and a memory 830. The RF processor 810 is connected to the processor 820 and transmits / receives a radio signal.

The processor 820 is an entity that performs functions, procedures, methods, and the like according to the present invention, and performs the operations of FIGS. 4 to 7 of the present invention. That is, it transmits a registration message for requesting a radio resource allocation or registering its own location in the network, receives a message for approval or rejection of network registration from an upper network, performs wireless connection to the network, Perform reselection. At this time, in performing wireless connection to different networks according to the present invention, it is possible to perform a scanning operation different in priority or an optional PLMN procedure. Particularly, in performing the scanning, the validity of the previously scanned result and the validity of the scanned cell are determined, and the scanning according to the priority is selectively performed. In addition, PLMN procedures may be optionally performed for selected PLMNs according to this priority. In other words, the UE according to the present invention may perform frequency scanning on all RATs and all bands supported by each RAT, but if necessary, The efficiency of the PLMN selection procedure may be provided by inducing a frequency of scanning and an optional PLMN selection procedure.

The memory 830 is connected to the processor 820 and includes information for supporting all the operations of the processor 820. [

Meanwhile, the base station 850 includes a radio signal processing unit (RF unit) 860, a processor 880, and a memory 870. The RF processor 860 is connected to the processor 880 and transmits / receives a radio signal.

The processor 880 is an entity for performing functions, procedures, and methods according to the present invention, and performs the operations of FIGS. 4 to 7 of the present invention. That is, the terminal 800 receives the registration message for location registration from the terminal 800 and delivers the registration message to the upper network. Or transmits information related to the measurement to the terminal 800 and provides information on the cell located in the terminal to the terminal 800. In addition, the terminal 800 is wirelessly connected to the terminal 800, and provides information on the necessary information, radio resource allocation, and information on the terminal 800 to the upper network.

The memory 870 is connected to the processor 880 and includes information for supporting all the operations of the processor 880.

The foregoing description is merely illustrative of the technical idea of the present invention and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (15)

A method for performing multiple wireless connections of a terminal in a wireless communication system,
Determining a priority for performing scanning by combining radio access networks (RAT) supported by the terminal and frequency bands supporting services in each RAT;
Confirming the validity of the scanning in the order of the network identification information (PLMN) having the highest priority according to the priority for performing the determined scanning;
And performing a wireless connection with at least one PLMN selected in consideration of the confirmed validity.
The method of claim 1, wherein the determining of the priority for performing the scanning comprises:
The priority order can be set in consideration of the location information acquired by the terminal,
Determines the priority in consideration of a PLMN (RPLMN) registered last by the terminal or a PLMN (HPLMN) subscribed by the terminal,
Wherein the location information includes mobile country codes in system information transmitted from a network.
The method of claim 1, wherein the step of verifying the validity of the scanning comprises:
Determining the validity of the time stamp for the previously performed scanning; and
Determining validity of the cell for scanning; and
And determining a validity of a previously performed scanning result. The method of claim 1,
4. The method of claim 3, wherein the determining of the validity of the time stamp comprises:
Determining whether the time stamp is smaller than a maximum value (T_max) determined to require a predetermined scanning, or determining whether the time stamp is less than a minimum value (T_min) determined to be not required to be scanned in advance The method comprising the steps of:
The method of claim 3, wherein the step of determining the validity of the cell for scanning comprises:
Determining whether the cell for scanning is a serving cell connected by the terminal or comparing the power of the corresponding cell measured through the interference with a preset power P_min if it is determined that the cell is not the serving cell; And determining the validity of the cell based on the cell identification information.
The method of claim 1, wherein the determining of the priority for performing the scanning comprises:
Combining the RATs and frequency bands supporting services in each RAT;
Confirming the result of the combination;
And allocating an index in order according to a priority order for performing the scanning on the identified result.
The method of claim 1, wherein the step of verifying the validity of the scanning comprises:
And performing no scanning for a PLMN corresponding to the index satisfying the validity. The method of claim 1,
The method of claim 1, wherein the step of verifying the validity of the scanning comprises:
And managing a PLMN corresponding to the index satisfying the validity by including the PLMN in a PLMN list for performing the multi-radio access.
A terminal apparatus for performing multiple wireless connections in a wireless communication system,
A radio processing unit for transmitting and receiving a radio signal,
Determining a priority for performing scanning by combining radio access networks (RATs) supported by the terminal and frequency bands supporting services in each RAT, connected to the radio processor, and performing the determined scanning (PLMN) having the highest priority according to a priority order for performing a wireless connection to at least one PLMN selected in consideration of the validity of the scanning The terminal device performing multiple wireless connections.
10. The apparatus of claim 9,
The RATs and the frequency bands supporting the services in the respective RATs are combined, the results of the combination are listed, and the indexes are sequentially allocated according to the priority for performing the scanning on the results of the combinations listed. The terminal apparatus performing multiple connections.
10. The apparatus of claim 9,
The validity of the scanning is checked in the order of the index having the highest priority, the PLMN corresponding to the index satisfying the validity is included in the PLMN list without performing the scanning on the PLMN corresponding to the index satisfying the validity And performs a wireless connection with at least one PLMN included in the PLMN list.
10. The apparatus of claim 9,
(RPLMN) registered last by the terminal, or a PLMN (HPLMN) subscribed by the terminal, considering the position information acquired by the terminal, And obtains the location information by checking the mobile country code in the system information transmitted from the network.
10. The apparatus of claim 9,
The validity of the time stamp for the previous scanning or the validity of the cell for the scanning or the validity of the scanning result that has been performed previously is determined Terminal device.
14. The apparatus of claim 13,
Judges whether the time stamp is smaller than a maximum value (T_max) judged to require a predetermined scanning, or judges whether the time stamp is smaller than a minimum value (T_min) judged not to require a predetermined scanning The terminal apparatus comprising:
14. The apparatus of claim 13,
The mobile station determines whether the cell for scanning is a serving cell connected by the terminal or compares the power of the corresponding cell measured through the interference with a preset power P_min if it is determined that the cell is not the serving cell, And judges the validity of the terminal connection.

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