KR20140021196A - Methods for reselceting cell of mobile terminal between heterogeneous networks - Google Patents

Abstract

Disclosed is a method for moving a heterogeneous terminal. After the UE moves from the first network to the second network due to CS fallback, when the call connection is terminated in the second network, the cell reselection time is set, and after the cell reselection time expires, MM (Mobility Management) / GMM (GPRS MM) determines whether the procedure is in progress, if the MM / GMM procedure is not in progress and performs cell reselection to the first network. Thus, it is possible to move quickly from the second network to the first network.

Description

METHODS FOR RESELCETING CELL OF MOBILE TERMINAL BETWEEN HETEROGENEOUS NETWORKS}

The present invention relates to a wireless communication system, and more particularly, to a method for moving between heterogeneous network terminals to allow a terminal to quickly reselect a cell among heterogeneous networks.

In addition to wired communication systems, wireless communication systems are accelerating data rates. As with the trend 4G mobile communication system such as the 3GPP (3 ^rd Generation Partnership Project) is LTE (Long Term Evolution) system has been commercialized.

If LTE is a standard for radically evolving wireless networks within 3GPP, SAE (System Architecture Evolution) is a standard for evolving core networks within 3GPP.

SAE focuses on packet-switching technologies that can support fast growing IP traffic by developing higher data rates, lower time delays, and packet-optimized systems.

In addition, EPC (Evolved Packet Core), a next-generation core network based on SAE, supports not only 3GPP-based wireless networks but also wireless networks of other standards organizations, and only service continuity for movement of terminals between 3GPP-based wireless networks. It also supports service continuity for mobility between 3GPP and non-3GPP wireless networks.

On the other hand, the voice call service, which is a basic service provided by a mobile communication network, has been provided using a circuit switched network in a network such as Global System for Mobile Telecommunication (GSM) or Wide Code Code Division Multiple Access (WCDMA). In this case, two methods are defined as standards for service in circuit-switched areas such as voice calls.

The first method is a method of providing a voice call service through Voice over Internet Protocol (VoIP) using IP Multimedia Subsystem (IMS). In this case, IMS should be additionally implemented in addition to LTE network and EPC.

The second method is to recycle existing circuit switching networks possessed by WCDMA, GSM, and CDMA networks. When a terminal registered in LTE network attempts to make a voice call, it provides a voice call service using the existing circuit switched network. It is a way.

Circuit Switched (CS) Fallback in EPS (Evolved Packet System) uses voice, video, SMS Refers to a technology that provides CS area services such as Short Message Service (LCS), Location Services (LCS), and Unstructured Supplementary Service Data (USSD).

A terminal supporting CS Fallback connected to the E-UTRAN may use GERAN (GSM / EDGE Radio Access Network) or UTRAN to connect to the CS area. Such a function is that the service coverage of the E-UTRAN is GERAN. Alternatively, this is possible only when it overlaps with the service provisioning area of UTRAN.

Due to CS fallback, the UE which redirects the network from the LTE network to GERAN or UTRAN determines the cell reselection condition after the end of the CS fallback, and if it meets the cell reselection condition again, the LTE network ( Or E-UTRAN).

For example, assuming that the E-UTRAN has a higher cell priority than the GERAN, the UE receives System Information (SI) broadcast from the network according to a Discontinuous Reception (DRX) cycle. The measurement is performed based on the system information. The UE determines parameter values such as RSRP (Reference Signal Received Power) and RSRQ (Reference Signal Received Quality) for each network according to the measured result, and satisfies the cell reselection condition when the determined parameter value is greater than or equal to a preset reference value. If so, the cell reselection procedure is performed.

In general, since the E-UTRAN can provide a faster data service than the GERAN or the UTRAN, it is preferable that the terminal quickly move to the E-UTRAN after the service of the circuit switched area in the GERAN or the UTRAN is terminated.

However, if the UE relocated to GERAN or UTRAN due to CS fallback is not satisfied with the cell reselection conditions, the UE will have to stay in GERAN or UTRAN, and this causes a problem that only low speed services can be provided.

An object of the present invention for overcoming the disadvantages as described above is to provide a method of moving between inter-network terminals to enable the UE moved to GERAN or UTRAN to move quickly to E-UTRAN with CS Fallback.

In order to achieve the above object of the present invention, a method for moving between heterogeneous networks according to an aspect of the present invention includes moving from a first network to a second network due to CS fallback, and ending a call connection in the second network. Setting a cell reselection time, determining whether a Mobility Management (MM) / GMM (GPRS MM) procedure is in progress after the cell reselection time has expired, and if the MM / GMM procedure is not in progress And performing cell reselection to the first network.

Here, the step of moving from the first network to the second network due to the CS fallback may be configured to move the terminal from the Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) to the GSM / EDGE Radio Access Network (GERAN).

Here, the method of moving between heterogeneous networks may wait until the MM / GMM procedure ends when the MM / GMM procedure is in progress after determining whether the MM / GMM procedure is in progress.

In this case, the method for moving a terminal between heterogeneous networks includes determining whether cell reselection is completed to the first network after performing cell reselection to the first network, and reselecting a cell to the first network. If not completed, the method may further include returning to the second network.

In addition, the method for moving between heterogeneous network terminals according to an aspect of the present invention for achieving the object of the present invention, the step of moving from the first network to the second network due to CS fallback, the call connection is terminated in the second network Setting a cell reselection time, determining whether a mobility management (MM) / GMM (GPRS MM) procedure is in progress before the cell reselection time expires, and if the MM / GMM procedure is not in progress And performing cell reselection to the first network.

Here, the method of moving the heterogeneous inter- terminal UE waits until the cell reselection timer expires and after the cell reselection time expires when the MM / GMM procedure is in progress before the cell reselection time expires. The method may further include determining whether an MM / GMM procedure is in progress. If the MM / GMM procedure is not in progress, performing a cell reselection to the first network may be performed.

Here, the method for moving the heterogeneous terminal between the terminals after the step of determining whether the MM / GMM procedure is in progress after the cell reselection time expires, until the MM / GMM procedure is terminated if the MM / GMM procedure is in progress I can wait.

Herein, the method for moving a terminal between heterogeneous networks includes determining whether cell reselection is completed to the first network after performing cell reselection to the first network, and reselecting a cell to the first network. If this is not completed, the method may further include returning to the second network.

According to the method for moving a heterogeneous terminal as described above, when the UE is moved from E-UTRAN to GERAN due to CS fallback and uses a service of the CS area, and the call connection is terminated, a cell reselection timer having a preset time is performed. After the expiration or before the expiration of the cell reselection timer, it is determined whether the MM / GMM signaling procedure is in progress and if the MM / GMM signaling procedure is determined to be terminated, the cell reselection is immediately performed by the E-UTRAN.

Therefore, after a call connection is terminated in GERAN, it is possible to move quickly to E-URTAN, thereby providing a service having a faster data rate than in GERAN.

In addition, if the connection or MM / GMM signaling procedure is in progress after the cell reselection timer expires, wait until the connection or MM / GMM signaling procedure is terminated, and then perform cell reselection to perform MM / GMM procedure after CS fallback. Is normally progressed so that the synchronization between the network and the terminal can be normally maintained even after the terminal moves to the E-UTRAN, thereby preventing paging loss to the terminal after the terminal moves from the GERAN to the E-UTRAN. .

1 is a conceptual diagram illustrating a network environment to which a network movement method of heterogeneous network terminals according to an embodiment of the present invention is applied.
2 is a flowchart illustrating a method for moving a heterogeneous network terminal according to an embodiment of the present invention.
3 is a flowchart illustrating a method of moving a heterogeneous network terminal according to another embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

The term "terminal" used in the present application is a mobile station (MS), a mobile terminal (MT), a user terminal, a user equipment (UE), a user terminal (UT: User Terminal), a wireless terminal, Access Terminal (AT), Subscriber Unit, Subscriber Station (SS), Wireless Device, Wireless Communication Device, Wireless Transmit / Receive Unit (WTRU), Mobile Node, Mobile And the like.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Hereinafter, the same reference numerals will be used for the same constituent elements in the drawings, and redundant explanations for the same constituent elements will be omitted.

1 is a conceptual diagram illustrating a network environment to which a network movement method of heterogeneous network terminals according to an embodiment of the present invention is applied.

Referring to FIG. 1, a user equipment (UE) 110 according to an embodiment of the present invention is located in the CS region of the UTRAN 130 and / or the GERAN 140 as well as the E-UTRAN 120 / EPC. Can be accessed. In addition, the terminal 110 may support CS fallback capability, combined EPS / IMSI (International Mobile Subscriber Identity) attach, combined TA / RA update, detach function, and an incoming / outgoing function of an SMS message.

The E-UTRAN 120 is a wireless access network of LTE, performs a function of delivering a paging request or SMS message for a CS fallback purpose to the terminal 110, and supports a direct connection function to a target cell capable of CS service.

UTRAN (130) and GERAN (140) is a radio access network in UMTS and GSM consisting of a base station, a radio network controller (RNC) / base station controller (BSC), etc., between the terminal 110 and the core network of the 3G mobile communication system It is located at and transfers data and control information based on Asynchronous Transfer Mode (ATM).

The mobility management node (MME) 150 performs CS fallback capability and combined EPS / IMSI attach, combined TA / LA update, detach, and SMS message processing from the terminal 110 and to the MSC 170. It supports SGs interface connection management.

Serving GPRS Supporting Node (SGSN) 160 is responsible for the management and support of packet switching services destined for wireless access networks, routing area update and location information registration for mobility management of terminals receiving packet switching services. , Paging, etc.

The MSC 170 supports CS Fallback, supports combined EPS / IMSI attach, combined TA / LA update, detach, SMS procedures from the MME 150, and supports SGs interface connection management to the MME 150. .

In FIG. 1, LTE-Uu represents a radio interface between the terminal 110 and the E-UTRAN 120, Uu represents a radio interface between the terminal 110 and the UTRAN 130, and Um represents a terminal 110. Represents an air interface between GERAN 140. In addition, S1-MME represents the air interface between the E-UTRAN 120 and the MME 150, and Gb and A respectively represent the GERAN 140 and SGSN 160 and the GERAN 140 and the MSC 170, respectively. Lu-ps and lu-cs represent the air interface between UTRAN 130 and SGSN 160 and between UTRAN 130 and MSC 170, respectively. S3 represents an interface between MME 150 and SGSN 160, and Gs represents an interface between SGSN 160 and MSC 170.

In addition, the SGs represent an interface between the MME 150 and the MSC 170, and are based on the Gs interface function.

2 is a flowchart illustrating a method for moving between inter-network terminals according to an embodiment of the present invention, after re-designating a network to GERAN due to CS fallback in a state where a terminal is initially registered in an LTE network (or E-UTRAN). For example, the case of moving to the LTE network is illustrated.

In the following description, it is assumed that a terminal and / or a network supports the Release 8 standard of 3GPP for convenience of description.

Referring to FIG. 2, first, a UE is initially registered in an E-UTRAN (or LTE network) and then moves from E-UTRAN to GERAN by performing a network redirection procedure for CS fallback.

Thereafter, the terminal connects a call in GERAN to perform a service of a CS domain, and then terminates the call connection (step 201).

In the conventional heterogeneous inter-network transfer method, when the UE moves from the E-UTRAN to the GERAN and terminates the call connection, the UE determines the cell reselection condition according to a preset criterion and satisfies the cell reselection condition. In the LTE network, a procedure for reselecting a cell is performed. When the cell reselection condition is not satisfied, a low-speed PS region service is used in GERAN without performing cell reselection.

The present invention provides a method for quickly performing cell reselection from GERAN to E-UTRAN in order to solve the above problems.

Specifically, when the call connection between the network and the terminal is terminated in the GERAN, the terminal sets a cell reselection timer (step 203). Here, the set time of the cell reselection timer may be determined as an optimal value obtained through repeated experiments in an actual mobile communication network, and may have a value between 2 seconds and 5 seconds, for example. However, the cell reselection timer setting time is not limited to the above values, and may be set to different values according to various conditions such as network environment, mobile communication system capability, capacity, and the like.

As described above, while the cell reselection timer is set and driven after a call is terminated in GERAN, an additional location update (LU) / routing area update (RAU) occurs to generate an MM / GMM signaling procedure. Can be executed (step 205). Here, the additional location update / routing area update procedure may be performed according to the procedure defined in the 3GPP standard.

Thereafter, when the cell reselection timer expires (step 207), the UE determines whether a connection or mobility management (MM) / GMM (GPRS MM) signaling procedure is in progress (step 209), and the MM / GMM signaling procedure is performed. If determined to be in progress, the connection or MM / GMM signaling procedure is terminated and waits for a channel release (step 211).

Thereafter, if the channel is released due to the termination of the connection or MM / GMM signaling procedure (step 213), the UE performs step 209 again to determine whether the connection or MM / GMM signaling procedure is in progress, and the connection or MM / GMM signaling procedure is performed. If all are determined to have ended, camping is attempted to the E-UTRAN cell based on the stored previous cell information (step 215).

Thereafter, the UE determines whether the cell reselection is completed by the E-UTRAN (step 217). When the cell reselection is completed by the E-UTRAN, the UE enters an idle mode in the E-UTRAN. Here, the terminal may wait for paging reception by performing a discontinuous reception (DRX) operation in the idle mode (step 219).

Or, if it is determined in step 217 that the cell reselection is not completed by the E-UTRAN, the terminal returns to the GERAN cell again (step 221). Here, the terminal may be configured to return to the GERAN when camping from the GERAN to the E-UTRAN for a predetermined time.

3 is a flowchart illustrating a method of moving a heterogeneous network terminal according to another embodiment of the present invention.

Referring to FIG. 3, first, a UE is initially registered in an E-UTRAN (or LTE network) and then moves from E-UTRAN to GERAN by performing a network redirection procedure for CS Fallback.

Thereafter, the terminal connects a call in GERAN to perform a service of a CS domain, and then terminates the call connection (step 301).

As described above, when the call connection between the network and the terminal is terminated in the GERAN, the terminal sets a cell reselection timer (step 303). Here, the set time of the cell reselection timer may be determined as an optimal value obtained through repeated experiments in the actual mobile communication network.

While the cell reselection timer is set and driven after the call has ended in GERAN, an additional location update (LU) / routing area update (RAU) may occur to execute the MM / GMM signaling procedure (step 305). Here, the additional location update / routing area update procedure may be performed according to the procedure defined in the 3GPP standard.

If the additional location update / routing area update procedure is executed after the cell reselection timer is set to a specific time, the UE determines whether the MM / GMM signaling procedure is terminated before the cell reselection timer expires (step 307). If it is determined that the GMM signaling procedure is terminated, the process proceeds to step 317 without waiting for the cell reselection timer to expire, and attempts to camp for cell reselection with the E-UTRAN, thereby heterogeneous according to an embodiment of the present invention shown in FIG. 2. It is possible to move to the E-UTRAN faster than the method of moving the manganese terminal.

Here, when the MM / GMM signaling procedure is terminated before the cell reselection timer expires as described above, the UE initializes (or resets) the cell reselection timer and attempts camping for cell reselection with the E-UTRAN. You may.

Or, if it is determined in step 307 that the MM / GMM signaling procedure is not terminated, the UE waits until the cell reselection timer expires, and when the cell reselection timer expires (step 309), the connection or MM It is determined whether the / GMM signaling procedure is in progress (step 311).

If it is determined that the MM / GMM signaling procedure is in progress, the UE waits for the channel to be released (channel 313) after the connection or MM / GMM signaling procedure is terminated.

Thereafter, if the channel is released due to the termination of the connection or MM / GMM signaling procedure (step 315), the UE performs step 311 again to determine whether the connection or MM / GMM signaling procedure is in progress, and the connection or MM / GMM signaling procedure is performed. If all are determined to have ended, camping is attempted to the E-UTRAN cell based on the stored previous cell information (step 317).

Thereafter, the UE determines whether cell reselection is completed by the E-UTRAN (step 319). When the cell reselection is completed by the E-UTRAN, the UE enters an idle mode in the E-UTRAN. Here, the terminal may wait for paging by performing a DRX operation in the idle mode (step 321).

Or, if it is determined in step 319 that the cell reselection is not completed by the E-UTRAN, the terminal returns to the GERAN cell again (step 323). Here, the terminal may be configured to return to the GERAN when camping from the GERAN to the E-UTRAN for a predetermined time.

As shown in FIG. 2 and FIG. 3, in the method of mobile terminal migration between heterogeneous networks according to the embodiments of the present invention, the terminal is moved from E-UTRAN to GERAN due to CS fallback to use the CS area service, and then call connection is performed. After the termination, the MM / GMM signaling procedure is terminated by driving a cell reselection timer having a preset time and determining whether the MM / GMM signaling procedure is in progress after the cell reselection timer expires or before the expiration of the cell reselection timer. If it is determined that cell reselection is performed directly to the E-UTRAN, it is possible to move quickly from the GERAN to the E-URTAN.

In addition, if the connection or MM / GMM signaling procedure is in progress after the cell reselection timer expires, wait until the connection or MM / GMM signaling procedure is terminated, and then perform cell reselection to perform MM / GMM procedure after CS fallback. Is normally progressed so that synchronization between the network and the terminal can be normally maintained even after the terminal moves to the E-UTRAN.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

110: terminal, UE 120: E-UTRAN
130: UTRAN 140: GERAN
150: MME 160: SGSN
170: MSC

Claims (8)

Moving from the first network to the second network due to CS fallback;
Setting a cell reselection time when call connection is terminated in a second network;
Determining whether a Mobility Management (MM) / GPRS MM (GMM) procedure is in progress after the cell reselection time has expired; And
And performing cell reselection to the first network when the MM / GMM procedure is not in progress. The method according to claim 1,
The step of moving from the first network to the second network due to the CS fallback is the movement of the inter-network between heterogeneous networks, characterized in that from Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) to GERAN (GSM / EDGE Radio Access Network) Way. The method according to claim 1,
The method for moving the heterogeneous inter- terminal terminal waits until the end of the MM / GMM procedure when the MM / GMM procedure is in progress after determining whether the MM / GMM procedure is in progress. How to go. The method according to claim 1,
The method for moving a terminal between heterogeneous networks may include determining whether cell reselection is completed in the first network after performing cell reselection in the first network; And
And returning to the second network when the cell reselection is not completed in the first network. Moving from the first network to the second network due to CS fallback;
Setting a cell reselection time when call connection is terminated in a second network;
Determining whether a mobility management (MM) / GPS MM (GMM) procedure is in progress before the cell reselection time expires; And
And performing cell reselection to the first network when the MM / GMM procedure is not in progress. The method according to claim 5,
The method of moving the heterogeneous terminal is a case where the MM / GMM procedure is in progress before the cell reselection time expires.
Waiting for the cell reselection timer to expire; And
Determining whether an MM / GMM procedure is in progress after the cell reselection time expires;
And performing a cell reselection to the first network when the MM / GMM procedure is not in progress. The method of claim 6,
The method for moving the heterogeneous inter- terminal terminal waits until the MM / GMM procedure is terminated when the MM / GMM procedure is in progress after determining whether the MM / GMM procedure is in progress after the cell reselection time has expired. A method of moving between heterogeneous manganese terminals. The method according to claim 1,
The method for moving a terminal between heterogeneous networks may include determining whether cell reselection is completed in the first network after performing cell reselection in the first network; And
And returning to the second network when the cell reselection is not completed in the first network.

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