KR20210040009A - Method and apparatus for location registration of terminal in mobile communication system - Google Patents

Abstract

A location registering method of a terminal in a mobile communication network and a device thereof are disclosed. When the terminal receives a rejection message for a location registration request from a network after transmitting a location registration request message to the network, it waits until disconnection of wireless connection from the network is completed and when the disconnection of the wireless connection is completed, a new location registration request message is transmitted to the network.

Description

[Method and apparatus for location registration of terminal in mobile communication system]

The present invention relates to a method and apparatus for registering a location of a terminal in a mobile communication network. More specifically, the present invention relates to a method and apparatus for efficiently using radio resources in terms of time reduction or resource saving compared to conventional methods and apparatuses in the process of handover of a terminal, location registration, and wireless connection re-establishment. will be.

Early wireless communication systems were developed to provide voice services while ensuring user activity. Moreover, wireless communication systems are gradually expanding their range to not only voice but also data services, and have developed to the extent that they can provide high-speed data services.

1 is a diagram showing a general wireless communication system. Referring to FIG. 1, a wireless communication system may include a terminal 100, a radio access network 120, a radio access network (RAN), and a core network 140.

The wireless access network 120 may include radio access points 110 and 115. The radio access points 110 and 115 may interact with the terminal 100 through a wireless interface. Other elements of the wireless communication system are mainly wired. As a possible example of the radio access point (110, 115), evolved node ratio (evolved Node B, eNB), node ratio (Node B, NB) or a radio network subsystem (Radio Network Subsystem, RNS) including the same, a base station ( There are Base Transceiver Station (BTS) or a base station subsystem (BSS) including the same, and a wireless access point. Except for a few exceptions, the radio access points 110 and 115 are generally composed of one or more cells, the cell governs a specific range, and the terminal 100 is from the radio access points 110 and 115 within the range of the cell. Receive service. Here, the cell refers to a cell of a general cellular system, and the radio access points 110 and 115 are devices that manage and control each cell, but in this specification, for convenience, the cell and the radio access points 110 and 115 are the same. Can be used as a meaning.

Meanwhile, the core network 140 may include a RAN control element 130 (RAN control entity). The RAN control element 130 is responsible for overall control functions such as mobility management, authentication, and security. As an example of the RAN control element, a mobility management element (MME) and a serving general packet radio service (GPRS) support element (Serving GPRS Support Node, SGSN) may be included.

In order to provide a service to the terminal 100, the wireless communication system including the radio access point 110 must maintain a connection with the terminal 100 or have the terminal 100-related information (context). In addition, the wireless communication system performs a handover process, a location registration process, or a wireless connection re-establishment process in order to maintain a connection with the terminal 100 or place a context related to the terminal 100 in a proper place.

The handover process is mainly used to change the interacting radio access point 110 as the connected terminal 100 moves or according to other reasons. An example of the other reason is load balancing.

The location registration process includes an attach process and a tracking area (TA) update (TA Update, TAU) process. The attach process may be used when the terminal 100 first accesses the network or when the detached terminal 100 accesses the network. The TAU process may be performed in more various situations, and a representative example of use may be performed when the terminal 100 enters a new TA.

In addition to the handover process and the location registration process mainly caused by the mobility of the terminal, the wireless connection between the terminal 100 and the radio access point 110 may be unstable and may not be suitable for use for a certain period of time. In this case, a wireless connection re-establishment process may be performed between the terminal 100 and the radio access point 110 before separately starting the handover process and the location registration process or without performing the handover process and the location registration process.

An object of the present invention is to provide a method and apparatus capable of efficiently using radio resources in terms of time reduction or resource saving by improving a handover process of a terminal, a location registration process, and a wireless connection re-establishment process.

An embodiment of the present invention for achieving the above technical problem is a method for registering a location of a terminal in a mobile communication system, comprising: transmitting a location registration request message to a network; When receiving a rejection message for the location registration request from the network, waiting until the wireless connection with the network is completed; And when the wireless connection is released, transmitting a new location registration request message to the network.

An embodiment of the present invention for achieving the above technical problem is a method for registering a location of a terminal in a mobile communication system, comprising: transmitting a location registration request message to a network; And upon receiving a rejection message for the location registration request from the network, immediately transmitting a new location registration request message to the network.

An embodiment of the present invention for achieving the above technical problem is a method for controlling a location registration of a base station in a mobile communication system, comprising: receiving a connection release command message corresponding to a location request of a terminal from a core network; And when the connection release command message is received, immediately transmitting a connection release message to the terminal.

An embodiment of the present invention for achieving the above technical problem is a method for controlling a location registration of a base station in a mobile communication system, comprising: receiving a connection release command message corresponding to a location request of a terminal from a core network; And waiting until a new location registration request message for the network is received from the terminal.

An embodiment of the present invention for achieving the above technical problem is a terminal for performing location registration in a mobile communication system, comprising: a transceiver for transmitting and receiving signals and data to and from a network; And transmitting a location registration request message to the network, and when receiving a rejection message for the location registration request from the network, waits until the wireless connection release with the network is completed, and when the wireless connection release is completed, And a control unit for controlling to transmit a new location registration request message to the network.

An embodiment of the present invention for achieving the above technical problem is a terminal for performing location registration in a mobile communication system, comprising: a transceiver for transmitting and receiving signals and data to and from a network; And a control unit that transmits a location registration request message to the network and, upon receiving a rejection message for the location registration request from the network, immediately transmits a new location registration request message to the network.

An embodiment of the present invention for achieving the above technical problem is a base station for controlling the location registration of a terminal in a mobile communication system, the transmission and reception unit for transmitting and receiving signals and data with the terminal and the core network; And a control unit configured to immediately transmit a connection release message to the terminal upon receiving a connection release command message corresponding to the location request of the terminal from the core network.

An embodiment of the present invention for achieving the above technical problem is a base station for controlling the location registration of a terminal in a mobile communication system, the transmission and reception unit for transmitting and receiving signals and data with the terminal and the core network; And a controller configured to receive a connection release command message corresponding to the location request of the terminal from the core network, and to wait until a new location registration request message for the network is received from the terminal.

According to the method and apparatus for registering a location of a terminal in a mobile communication network according to the present invention, it is possible to efficiently use radio resources in terms of time reduction or resource saving.

1 is a diagram showing a general wireless communication system;
2 is a diagram showing an example of a situation in which a first problem may occur;
3 is a diagram showing a terminal and a network operation to which the first and second embodiments of the present invention can be applied;
4 is a diagram specifically showing the operation of a RAN control element and a radio access point according to a second embodiment of the present invention;
FIG. 5 is a flowchart illustrating a process of transmitting a location registration message of a terminal 100 in which a radio access point reuses radio resources in a second embodiment of the present invention.
6 is a diagram illustrating a process of recognizing that a terminal to which a radio access point is handed over is a secondary service terminal according to an embodiment of the present invention related to a handover of a terminal;
FIG. 7 is a flow chart illustrating a process of re-establishing a wireless connection by reusing a wireless connection with a radio access point that a terminal interacted with according to an embodiment of the present invention related to re-establishment of a wireless connection of a terminal;
8 is a block diagram showing the configuration of a terminal according to an embodiment of the present invention, and,
9 is a block diagram showing the configuration of a base station according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this case, it should be noted that the same components in the accompanying drawings are indicated by the same reference numerals as possible. In addition, detailed descriptions of known functions and configurations that may obscure the subject matter of the present invention will be omitted.

In addition, in describing the embodiments of the present invention in detail, the wireless access network specified by the 3GPP, the core network of LTE (Long Term Evolution, LTE) and the evolved packet core (Evolved Packet Core, EPC) will be the main targets. , The main subject of the present invention can be applied to other communication systems having a similar technical background with slight modifications without significantly departing from the scope of the present invention. It will be possible with judgment.

In the past, the terminal 100 mainly interacted with one radio access point 110, but recently, it has become possible to interact with one or more radio access points 110 and 115 as well. For example, as described above, two radio access points 110 and 115 connected to the terminal 100 are shown in FIG. 1. However, the present invention is not limited to the embodiment shown in FIG. 1, and the wireless access network 120 is not necessarily composed of two radio access points 110 and 115, and the terminal 100 always has two radios. It is obvious that it does not interact with the connection points 110 and 115.

Hereinafter, throughout this specification, unless otherwise described, when only one radio access point 110 is referred to, the radio access point 110 refers to a general radio access point, and both radio access points 110 and 115 are referred to together. In this case, the first radio access point 110 is a radio access point 110 that primarily interacts with the terminal 100, and the second radio access point 115 is secondary to the terminal 100. Refers to the working radio access point 115. In addition, when the number of radio access points 110 and 115 connected to the terminal 100 is three or more, there may be one or more radio access points 115 that secondaryly interact with the terminal 100.

In the network structure described above, the following problems may occur. One is that it may take a long time when the terminal 100, which has failed to register the location for a specific reason, re-registers the location at the corresponding radio access point 110, and the other is that it interacts with two or more radio access points 110 and 115. When the connection state with the radio access point 110 that the terminal primarily interacts with is bad, the connection state with the radio access point 115 that interacts with the secondary (secondarily) is not considered at all, resulting in a waste of resources. Is that there is. Hereinafter, the problem situation will be described in more detail.

2 is a diagram illustrating an example of a situation in which a first problem may occur. First, in FIG. 2, the terminal 100 is location registered or received service in a wireless communication system using another radio access technology (RAT), or in another RAN control element group having a different RAN control element group identifier. Could have been. Alternatively, the terminal may have been in an idle state.

When the terminal 100 is moved from another RAT or another RAN control element group, such as 210, the terminal sends a TAU request message to the RAN control element 130, such as 220. Alternatively, when the terminal generates data to be transmitted to the network or received from the network in an idle state as shown in 215, the terminal sends a service request message to the RAN control element 130 at 220. At this time, the message sent from the terminal 100 to the RAN control element 130 is not directly transmitted from the terminal 100 to the RAN control element 130, but is transmitted through the radio access point 110.

The RAN control element 130 receiving the TAU request message or the Service request message from the terminal 100, if a problem occurs, a message that rejects the request message of the terminal 100, such as 240, for example, a TAU reject message or a service reject message Can be sent to the terminal 100. In this case, the RAN control element 130 may send information explaining or suggesting the cause of the problem in the reject message. In addition, the reject message is not directly transmitted from the RAN control element 130 to the terminal 100, but is transmitted to the terminal 100 through the radio access point 110.

The terminal 100 receiving the rejection message from the RAN control element 130 at 240 may send a new Attach request message to the RAN control element 130 through the radio access point 110 for a specific cause included in the rejection message. (280). Here, as an example of a specific cause, when the RAN control element 130 does not obtain the identifier of the terminal 100, when the terminal 100 is implicitly detached, bearer information is activated at all. If not, etc. These three causes are matched to cause values 9, 10, and 40, respectively, in the evolved packet system (EPS).

Meanwhile, the RAN control element 130 that sends a reject message to the terminal 100 at 240 may issue a command to release the context related to the terminal 100 to the radio access point 110 at 250. This command may be delivered through a UE CONTEXT RELEASE COMMAND message.

In addition, the radio access point 110 receiving the release command from the RAN control element 130 may send a message to release the connection to the terminal 100 as shown in 260. An example of a release message transmitted from the radio access point 110 to the terminal 100 is an RRCConnectionRelease message.

At this time, the time when the release message transmitted from the radio access point 110 to the terminal 100 arrives at 260 and the radio connection with the network is completed is 280, and the terminal 100 sends a new Attach request to the RAN control element 130. If it is earlier than the time to send the message, the terminal 100 may perform the Attach process without any problem.

However, at 260, when the release message transmitted from the radio access point 110 to the terminal 100 arrives and the radio connection with the network is completed at 280, the terminal 100 sends a new Attach request to the RAN control element 130. Problems can arise if it is later than when the message is sent. In other words, this situation means that the wireless connection is released after the terminal 100 sends an Attach request message to the RAN control element 130. Accordingly, the terminal 100 recognizes that a problem has occurred in the attach process, waits for a relatively long period (eg, 10 seconds), and then attempts to register the location again. While waiting for such a long period of time, the terminal 100 cannot be provided with a service, and the user of the terminal 100 has to bear the inconvenience.

Hereinafter, an embodiment of the present invention for solving the problem as shown in FIG. 2 will be described in detail. However, it is obvious that the problem to be solved in the present invention is not limited to the situation shown in FIG. 2, but is for all situations in which a long time may take when a terminal that has failed to register a location for a specific reason re-registers its location at the corresponding radio access point Do.

In order to solve the above-described problem, two embodiments of the present invention are possible. However, it is obvious that all possible modifications that can achieve the technical idea of the present invention can be made in addition to the embodiments to be described below.

In the first embodiment according to the present invention, based on FIG. 2, when the arrival time of the release message transmitted from the radio access point 110 to the terminal 100 at 260 is 280, the terminal 100 controls the RAN control element ( 130) to the point of sending a new Attach request message.

In addition, according to the second embodiment of the present invention, the connection between the terminal 100 and the radio access point 110 is not released, that is, 260 is not performed in the case of FIG. 2. Therefore, according to the second embodiment of the present invention, a release message from the radio access point 110 is not transmitted to the terminal 100.

The fundamental difference between the above first and second embodiments is whether or not the wireless connection is reused. That is, in the first embodiment, the connection between the terminal 100 and the radio access point 110 must be released, and the terminal 100 makes a new location registration request. On the other hand, in the second embodiment, without releasing the connection between the terminal 100 and the radio access point 110, the terminal 100 reuses the existing wireless connection to request a new location.

In both the first and second embodiments, the release message transmitted from the radio access point 110 to the terminal 100, which was a problem in FIG. 2, arrives at the terminal and the time 260 when the wireless connection is released is the terminal 100. Time reduction effect in that it is possible to prevent a situation that is delayed than the timing 280 of transmitting a new location registration request to the RAN control element 130, and prevents the case that the terminal waits for a long period and then makes a location registration request again. There is.

3 is a diagram showing a terminal 100 and a network operation to which the first and second embodiments of the present invention can be applied. Specifically, the terminal 100 from the RAN control element 130 to the radio access point 110 It shows an operation of transmitting at least one of an indicator and a timer indicating that a new location registration is required, or in which the RAN control element 130 or the radio access point 110 transmits the timer to the terminal 100.

Referring to FIG. 3, the terminal 100 and the radio access point 110 may recognize a situation in which a new location registration process is required. In addition, the terminal 100 or the radio access point 110 may send a message to be transmitted during a new location registration process or wireless connection release process performed based on a timer at an appropriate time.

In step 310, the RAN control element 130 may determine that a new location registration of the terminal 100 is required in a specific problem situation. Here, the specific problem situation may be a situation corresponding to at least one of 9, 10, and 40 cause values in the case of EPS as described above. In addition, the determination made by the RAN control element 130 in step 310 may be a determination according to a location registration of the terminal 100 or a service request.

In step 320, the RAN control element 130 may transmit at least one of a timer and an indicator notifying that a new location registration of the terminal 100 is required to the radio access point 110. At this time, information transmitted from the RAN control element 130 to the radio access point 110 may be delivered through a DOWNLINK NAS TRANSPORT message. The DOWNLINK NAS TRANSPORT message is used to deliver a non-access stratum (NAS) message between the terminal 100 and the RAN control element 130. Examples of NAS messages delivered as DOWNLINK NAS TRANSPORT messages include TAU reject and Service reject. Meanwhile, information transmitted from the RAN control element 130 to the radio access point 110 may be transmitted through a UE CONTEXT RELEASE COMMAND message that commands disconnection from the terminal 100.

In addition, an indicator indicating that the terminal 100 needs to register a new location may be expressed in various ways. For example, the indicator may be expressed as simple binary information, or may be expressed as a reason or a cause value in which a new location registration of the terminal 100 is required.

In step 330, the radio access point 110 may transmit a timer to the terminal 100. The timer to the terminal 100 may be included in the DLInformationTransfer message or the NAS message entered in the DLInformationTransfer message.

Meanwhile, the timer transmitted from the RAN control element 130 to the radio access point 110 in step 320 and the timer transmitted from the radio access point 110 to the terminal 100 in step 330 may be set to the same value or different from each other. It can also be set to a value.

Hereinafter, at least one of an indicator and a timer indicating that the radio access point 110 needs to register a new location of the terminal 100 from the RAN control element 130 according to the first embodiment of the present invention in a situation as shown in FIG. 3. The operation of the RAN control element 130 and the radio access point 110 will be described in detail when both are received and when neither is received.

When the radio access point 110 does not receive both the indicator and the timer from the RAN control element 130, the network needs to release the radio connection as quickly as possible before the terminal 100 requests a new location registration. .

Accordingly, when the RAN control element 115 recognizes a situation in which a new location registration of the terminal 100 is required, the RAN control element 115 may send the UE CONTEXT RELEASE COMMAND message to the radio access point 110 as quickly as possible. For example, upon sending a NAS message notifying that location registration rejection is sent to the terminal 100, the UE CONTEXT RELEASE COMMAND message may be sent to the radio access point 110. In addition, the radio access point 110 may disconnect the wireless connection of the terminal 100 immediately upon receiving the UE CONTEXT RELEASE COMMAND message from the RAN control element 130. For example, upon receiving the UE CONTEXT RELEASE COMMAND message from the RAN control element 130, the radio access point 110 may send a connection release message, an RRCConnectionRelease message, to the terminal 100. In addition, the terminal 100 may perform wireless connection release immediately upon receiving a connection release message from the radio access point 110.

When the radio access point 110 receives an indicator from the RAN control element 130 but does not receive a timer, the radio access point 110 recognizes that the terminal 100 requests a new location registration through the indicator. Accordingly, the radio access point 110 may cause the RAN control element 130 to disconnect the wireless connection of the terminal 100 as soon as it recognizes a situation in which a new location registration is required through the indicator, regardless of whether the RAN control element 130 sends the UE CONTEXT RELEASE COMMAND message. .

For example, if the indicator is received through the UE CONTEXT RELEASE COMMAND message, the radio access point 110 immediately transmits an RRCConnectionRelease message to the terminal 100, and if the indicator is received through another type of message, the UE CONTEXT RELEASE COMMAND message is received. Even before, the RRCConnectionRelease message may be immediately transmitted to the terminal 100.

When the radio access point 110 receives a timer from the RAN control element 130, the radio access point 110 may terminate the wireless connection of the terminal 100 within a time indicated or symbolized by the timer from an appropriate time point. Here, it can be seen that the timer serves as a kind of appointment. For example, the terminal 100 may be regarded as a promise not to make a new location registration request to the RAN control element 130 at least within a time indicated or symbolized by a timer received by the radio access point 110. In addition, an example of an appropriate time point at which the timer is started may be a time point at which the radio access point 110 receives the timer.

Next, a configuration in which the terminal 100 requests a new location registration by reusing a wireless connection according to the second embodiment of the present invention in a situation as shown in FIG. 3 will be described in detail.

When the radio access point 110 does not receive both the indicator and the timer indicating that the terminal 100 needs to register a new location in step 320 of FIG. 3, the radio access point 110 reuses the wireless connection that the terminal 100 already exists. Therefore, it is necessary to maintain a wireless connection for a certain period of time with a margin so that a new location can be requested. Here, the predetermined period may be determined by a timer unique to the radio access point 110.

Therefore, if the RAN control element 115 recognizes a situation in which a new location registration of the terminal 100 is required in step 310, the UE CONTEXT RELEASE COMMAND message may not be sent to the radio access point 110 in step 320. In addition, even if the radio access point 110 receives the UE CONTEXT RELEASE COMMAND message from the RAN control element 130, it may wait for a certain period of time without releasing the wireless connection of the terminal 100.

When the terminal 100 performs a new location registration request for the RAN control element 130 while the radio access point 110 is waiting, the radio access point 110 receives a UE CONTEXT RELEASE COMMAND message from the RAN control element 130 Despite this, the wireless connection of the terminal 100 may not be released.

When the radio access point 110 receives an indicator from the RAN control element 130 but does not receive a timer, the radio access point 110 recognizes that the terminal 100 requests a new location registration. Therefore, the radio access point 110, regardless of whether the RAN control element 130 sends a UE CONTEXT RELEASE COMMAND message, through the indicator, when recognizing a situation in which a new location registration of the terminal 100 is required, the wireless connection of the terminal 100 is established. It is possible to wait until a new location registration request is received from the terminal 100 without release. In addition, the waiting time of the radio access point 100 may be maintained during a timer period unique to the radio access point 110.

When the radio access point 110 receives a timer from the RAN control element 130, the radio access point 110 may not disconnect the wireless connection of the terminal 100 from an appropriate time point for a time indicated or symbolized by the timer. Here, it can be seen that the timer serves as a kind of appointment. For example, the terminal 100 may be regarded as a promise to make a new location registration request within a time indicated or symbolized by a timer received by the radio access point 110. In addition, an example of an appropriate time point at which the timer is started may be a time point at which the radio access point 110 receives the timer.

Next, the operation of the terminal 100 according to the first and second embodiments of the present invention in the situation shown in FIG. 3 will be described in detail.

According to the first embodiment of the present invention, when the terminal 100 does not receive a timer from the network in step 330 of FIG. 3, the terminal 100 waits until the wireless connection is disconnected by the radio access point 110, and then You can try to request a location registration.

Alternatively, the terminal 100 may attempt to request a new location registration by using a method applying the above method. That is, the terminal 100 waits for the wireless connection to be disconnected for a certain period of time, and then releases the wireless connection with the radio access point 110 after a certain period of time, and establishes a new connection with the radio access point 110 to request a location registration. You can try.

In addition, when the terminal 100 receives the timer in step 330, it may wait for at least the time indicated or symbolized by the timer, and then attempt a new location registration request. In this case, if the wireless connection is first released while waiting for the timer to expire, the terminal 100 may immediately stop the timer and attempt a new location registration request.

In addition, since the terminal 100 can recognize that a new location registration is required from a message received from the network in step 330 of FIG. 3, for example, a location registration rejection message, it is possible to disconnect the wireless connection as quickly as possible in terms of time reduction. You can see that it's efficient. Accordingly, when the terminal 100 receives a message to release the wireless connection from the radio access point 110, the terminal 100 may immediately leave the connected state without delay. The information received so that the terminal 100 can recognize that a new location registration process is required may be information received from the NAS layer. In addition, the NAS layer may deliver the information to the RRC layer so that the terminal 100 can immediately exit the connected state without delay.

In a specific situation, some terminals 100 are currently designed to delay the wireless connection release process for a period of 60 ms when receiving a wireless connection release message from the radio access point 110. Accordingly, in an embodiment of the present invention, the terminal 100 leaving the connected state'without delay' may mean'within 60 ms after receiving a message' or'without a waiting time of 60 ms'.

Next, according to the second embodiment of the present invention, if the terminal 100 does not receive the timer in step 330 of FIG. 3, the terminal can transmit a new location registration request to the RAN control element 130 immediately after step 330. have. In addition, when the terminal 100 receives the timer in step 330, the terminal may transmit a new location registration request to the RAN control element 130 within a time as long as a value indicated or symbolized by the timer.

Meanwhile, a third embodiment in which the terminal 100 determines whether to reuse the wireless connection for new location registration according to the situation is also possible.

Specifically, according to the third embodiment of the present invention, in step 310 of FIG. 3, the RAN control element 130 may start a timer when it is determined that a new location registration of the terminal 100 is required. Here, the timer may be the same as or different from the timer transmitted to the radio access point 110 by the RAN control element 130. In addition, the timer of the RAN control element 130 may be started after at least one of the indicator and the timer is transmitted to the radio access point 110 through a location registration related message in step 320 or at the same time.

Thereafter, if the terminal 100 transmits a new location registration request to the RAN control element 130 before the timer expires, the RAN control element 130 transmits a UE CONTEXT RELEASE COMMAND message to the radio access point 110 for wireless connection. The location of the terminal 100 can be registered without cancellation. That is, location registration is performed by reusing the wireless connection. When the terminal 100 attempts to register a location before the timer expires, the RAN control element 130 may stop or terminate the timer upon receiving the location registration request message.

On the other hand, if the terminal 100 does not transmit a new location registration request until the timer expires, the RAN control element 130 triggers radio connection release. The triggering of wireless connection release may be performed by transmitting a UE CONTEXT RELEASE COMMAND message to the radio access point 110.

4 is a diagram specifically showing the operation of the RAN control element 130 and the radio access point 110 according to the second embodiment of the present invention.

As described above, according to the second embodiment of the present invention, even if the RAN control element 130 transmits a UE CONTEXT RELEASE COMMAND message to the radio access point 110 to command the context release, the radio access point 110 ) The related context may not be released or the wireless connection may not be released. Accordingly, the radio access point 110 may inform the RAN control element 130 that it has not released a context related to the terminal 100 or has not released a radio connection. When the terminal 100 reuses an existing wireless connection to perform a new location registration request, the radio access point 110 establishes a wireless connection for a certain period even if a context release or a wireless connection release is requested from the RAN control element 130. We have previously explained that there are cases in which it is necessary to maintain.

Referring to FIG. 4, in step 410, the RAN control element 130 may send a message instructing the context release of the terminal 100 to the radio access point 110. An example of a message transmitted in step 410 is a UE CONTEXT RELEASE COMMAND message. The radio access point 110 receiving a message from the RAN control element 130 may not perform context release or may not perform radio connection release despite the command of the RAN control element 130.

In addition, in step 420, the radio access point 110 may notify through a message transmitted to the RAN control element 130 that it has not released a context related to the terminal 100 or has not released a radio connection. An example of the message transmitted in step 420 may be at least one of UE CONTEXT RELEASE COMPLETE and ERROR INDICATION messages. At this time, the message transmitted from the radio access point 110 to the RAN control element 130 may contain an information element (IE) indicating that the context related to the terminal 100 has not been released or that the wireless connection has not been released. Examples of IEs that can be included in a message include a cause and an indicator having a specific value.

Also, a message transmitted from the radio access point 110 to the RAN control element 130 may be a new type of message. When an IE indicating that the UE 100-related release has not been performed is transmitted through a new message, as an embodiment, the new message name may be UE CONTEXT RELEASE FAILURE.

In the past, if the RAN control element 130 commanded the context release, the radio access point 110 had to operate according to the command of the RAN control element 130. However, according to the second embodiment of the present invention described above, the radio access point 110 may not release a context or may not release a wireless connection in a specific situation.

On the other hand, when FIG. 4 is applied to the third embodiment of the present invention, in step 410 when the RAN control element 130 does not receive a new location registration request from the terminal 110 until its timer expires, The context release command is sent. In addition, even if the timer of the RAN control element 130 expires and a context release command is transmitted to the radio access point 110, if the timer of the radio access point 110 itself expires, the radio access point 110 controls the RAN as in step 420. A message indicating that context release has not been performed may be transmitted to the element 130.

FIG. 5 is a flowchart illustrating a process in which the radio access point 110 transmits a location registration message of the terminal 100 that reuses radio resources in the second embodiment of the present invention.

According to the process illustrated in FIG. 5, the radio access point 110 can successfully transmit the corresponding message to the RAN control element 130 even when the terminal 100 reuses radio resources and sends a location registration request message.

Referring to FIG. 5, in step 510, the terminal 100 transmits a message requesting location registration to the radio access point 110. The message transmitted by the terminal 100 may ultimately be a NAS message sent to the RAN control element 130, and may be transmitted through , for example, a ULInformationTrnasfer message. According to the second embodiment of the present invention, when the terminal 100 re-uses the wireless connection and makes a new location registration request, the terminal may send a location registration request message with specific information. The specific information included in the message may be used to inform that the terminal 100 re-uses the wireless connection and makes a new location registration request.

In step 520, the radio access point 110 may transmit a location registration request message of the terminal 100 to the RAN control element 130. At this time, at least one of INITIAL UE MESSAGE and UPLINK NAS TRANSPORT messages may be used to deliver the message of the terminal 100.

The existing location registration request message is mainly delivered through INITIAL UE MESSAGE. Unlike the UPLINK NAS TRANSPORT message and the DOWNLINK NAS TRANSPORT message, which transfer general NAS messages, a special IE is defined so that the INITIAL UE MESSAGE is suitable for delivering the location registration message. In addition, INITIAL UE MESSAGE is limited to deliver the first NAS message sent after a wireless connection is established.

However, when the wireless connection is reused, it may be necessary to deliver a location registration request message in addition to the first NAS message sent after the wireless connection is established. Accordingly, the radio access point 110 needs to be changed so that it can send the INITIAL UE MESSGAE even in a situation different from the situation in which the first NAS message is transmitted after the wireless connection of the terminal 100 is established. Here, as an example of another situation, there is a case in which the terminal 100 transmits specific information through a ULInformationTransfer message, and a case in which the RAN control element 130 informs that the terminal 100 is to request a new location registration.

In addition, when the message transmitted by the radio access point 110 is a UPLINK NAS TRANSPORT message, the UPLINK NAS TRANSPORT is sometimes not used when sending a location registration request message, so the radio access point 110 is an IE included in the INITIAL UE MESSAGE. For example, one or more of RRC Establishment Cause, S-TMSI, CSG Id, GUMMEI, Cell Access Mode, Relay Node Indicator, GUMMEI Type, and Tunnel Information for BBF may be included in the UPLINK NAS TRANSPORT message.

When FIG. 5 is applied to the third embodiment of the present invention, if the location registration request message of the terminal 100 is transmitted before the timer of the RAN control element 130 expires, the RAN control element 130 establishes a radio connection. By reuse, the location of the terminal 100 can be registered.

Next, a second problem to be solved by the present invention will be described.

The second problem is based on a case in which the terminal 100 interacts with two or more radio access points 110 and 115 as shown in FIG. 1. When the wireless connection state with the radio access point 110 to which the terminal 100 mainly interacts deteriorates below a certain level, the terminal 100 may change the radio access point that the terminal 100 mainly interacts with through a handover process. In this case, a new radio access point that primarily interacts with the terminal 100, that is, a target radio access point, may be the radio access point 115 that previously interacted with the terminal 100 secondary.

In the existing handover process, a mechanism for reusing all or part of the wireless connection between the radio access point 115 and the terminal 100, which previously interacted with the terminal 100, has not been defined. There is no significant difference between the case of handover to the radio access point 115 that has secondary interaction with 100) and the case of handover to the radio access point that has no interaction with the terminal 100 before.

On the other hand, when the radio access point 110 primarily interacting with the terminal 100 fails to start handover of the terminal in time, a radio connection failure between the terminal 100 and the radio access point 110 primarily interacting with the terminal 100 (Radio Link Failure, RLF) or Handover Failure (HOF) may occur. The terminal 100 that has undergone RLF or HOF with the radio access point 100 that mainly interacts may attempt to re-establish a wireless connection. In this case, the target to which the terminal 100 attempts to re-establish a wireless connection may be a radio access point 115 that secondaryly interacts with the terminal 100.

Even when the terminal 100 experiences an RLF or HOF with the radio access point 110 that primarily interacts, the wireless connection state between the radio access point 115 and the terminal 100 that interacts with the secondary is good, so that the wireless connection continues. It can be well maintained. However, the existing wireless connection re-establishment process proceeded without consideration of the wireless connection state between the radio access point 115 and the terminal 100, which are secondary interactions. In addition, according to the existing wireless connection re-establishment process, the wireless connection re-establishment may be performed after all connections between the radio access point 115 and the terminal 100 that interact with each other are disconnected.

That is, in the handover process and the wireless connection re-establishment process of the terminal 100 as described above, if there is a radio access point 115 that secondaryly interacts with the terminal 100, the existing radio resource is reused and the resource Although saving can be achieved, a mechanism reflecting this has not been defined in the past.

First, with respect to the handover of the terminal 100, the terminal 100 or the radio access point 115 recognizes that the target radio access point 115 is the radio access point 115 that has secondary interaction before handover, and then has already The existing wireless connection can be reused to complete the wireless connection reconfiguration process.

Next, in relation to the re-establishment of the wireless connection of the terminal 100, the terminal 100 or the radio access point 115 is a radio access point 115 that has previously interacted with the wireless connection re-establishment target. The connection can be reused to complete the wireless connection re-establishment process.

In both of the above methods, the wireless connection with the radio access point 115, which has been secondary to the existing interaction, is reused to perform a necessary process, so that resource saving can be achieved.

Hereinafter, an embodiment of the present invention will be described in detail with respect to handover of the terminal 100 and re-establishment of a wireless connection.

First, in the handover process of the terminal 100, the terminal 100 or the radio access point 115 recognizes that the target radio access point 115 is the radio access point 115 that has secondary interaction before handover, and then already exists. The wireless connection reconfiguration process can be completed by reusing the wireless connection.

The terminal 100 may recognize that the target radio access point 115 is a radio access point 115 that has secondary interactions before handover, even with an existing mechanism. However, the target radio access point 115 may not be able to recognize that the terminal 100 performing the handover is the terminal 100 that has previously interacted with each other.

6 is a diagram illustrating a process of recognizing that the terminal 100 to which the radio access point 115 is handed over is the terminal 100 serving as a secondary service according to an embodiment of the present invention related to the handover of the terminal 100 to be.

6, in step 610, the radio access point 110 that mainly serves the terminal 100, that is, the primary radio access point 110 is a message requesting that the radio access point 115 secondaryly service the terminal 100 Can be sent. The name of the request message transmitted here may be SCELL ADDITION REQUEST MESSAGE. In addition, the request message may include at least one of an identifier used by the radio access point 110 to identify the terminal 100 and an identifier recommended to be used by the radio access point 115 to identify the terminal 100. The included identifier may mean at least one of C-RNTI and eNB UE X2AP ID.

The message delivered in step 610 may include additional information in addition to the identifier in order to successfully request the radio access point 115 to serve the terminal 100 as a secondary service. For example, the sub-identifier of the radio access point 115, bearer information desired to be serviced by the radio access point 115, access restriction information of the terminal 100, the RAN control element 130 in charge of the terminal 100, the RAN The identifier used by the control element 130 to identify the terminal 100, the security capabilities of the terminal 100, AS-related security information, the aggregate maximum bit rate (AMBR) of the terminal 100 ), one or more of CSG membership status can be sent.

The sub-identifier of the radio access point 115 may be expressed in the form of an E-UTRAN Cell Global Identifier (ECGI). When the radio access point 115 is an eNB, it may be necessary to send an ECGI for cell-level division within the eNB. Meanwhile, the bearer information desired to be serviced by the radio access point 115 may include at least one of a bearer identifier and a bearer QoS parameter. If the element indicated by the lower identifier of the radio access point 115 is permitted to service one or more of the bearers indicated by the bearer identifier contained in the bearer information desired to be serviced by the radio access point 115, the radio access point 115 You may need to reserve the resources you need.

The resource usage restriction information of the terminal 100 may include information on resources that the terminal 100 cannot use or resources that can be used. The resource use restriction information may mean a handover restriction list (HRL). Since HRL is mobility-related information, new information on resource use may be used.

The radio access point 115 receiving the identifier of the RAN control element 130 in charge of the terminal 100 manages the terminal 100 when it is necessary to interact with the RAN control element 130 for the terminal 100 The RAN control element 130 may be identified using the RAN control element 130 identifier. In addition, when the RAN control element 130 interacts with the RAN control element 130 using an identifier used to identify the terminal 100, the terminal 100 may be identified.

The radio access point 115 prepares an AS security configuration by referring to at least one of Security Capabilities and AS-related security information of the terminal 100.

The radio access point 115 may schedule so that the sum of bit rates of specific bearers serving the terminal 100 does not exceed the AMBR of the terminal 100. The specific bearer may mean all bearers that the radio access point 115 serves to the terminal 100 or all data bearers that the radio access point 115 serves to the terminal 100.

The CSG membership status indicates the result of membership verification or access control performed by the terminal 100 or the terminal 100 and the radio access point 110 with respect to the radio access point 115. If the radio access point 115 determines that the CSG membership status is incorrect, the radio access point 115 may send the correct CSG membership status in step 620 or reject the request itself.

In step 620, the radio access point 115, that is, the secondary radio access point 115, may send a message to the radio access point 110 that it accepts the secondary service of the terminal 100. The name of the acceptance message transmitted here may be SCELL ADDITION ACKNOLEDGE. In addition, the acceptance message may include an identifier to be used or used by the radio access point 115 to identify the terminal 100. The included identifier may be at least one of C-RNTI and eNB UE X2AP ID. The acceptance message may include at least one of bearer information accepted by the radio access point 115 and bearer information not accepted among bearers requested to be serviced by the radio access point 110.

In step 630, the primary radio access point 110 may send a message to the secondary radio access point 115 requesting a handover of the terminal 100. The handover request message may be a HANDOVER REQUEST message. In addition, the HANDOVER REQUEST message may include an identifier received from the secondary radio access point 115 in step 20.

In step 640, the secondary radio access point 115 may send a message accepting the handover to the primary radio access point 110. The handover acceptance message may be a HANDOVER REQUEST ACKNOWLEDGE message. In addition, the handover accept message may include a RRCConnectionReconfiguartion message, RRCConnectionReconfiguartion message may include information used for terminal 100 is omitted, at least one of a random access procedure (Random Access Procedure), uplink synchronization, uplink assignment have. This information can be expressed as a bitmap.

The RRCConnectionReconfiguartion message received from the secondary radio access point 115 may be delivered to the terminal 100, and accordingly, the terminal 100 may omit the random access process during the handover process to the secondary radio access point 115.

FIG. 7 is a diagram illustrating re-establishment of a wireless connection by reusing a wireless connection with a radio access point 115 that the terminal 100 has interacted with in accordance with an embodiment of the present invention related to the re-establishment of the wireless connection of the terminal 100. It is a flow chart showing the process.

Referring to FIG. 7, in step 710, the terminal 100 detects the RLF or HOF of the primary radio access point 110. In addition, the terminal 100 may detect that the radio access point 115 to which a message requesting re-establishment of a wireless connection is transmitted is the radio access point 115 that has interacted with the secondary radio access point 115, that is, a secondary radio access point 115. Accordingly, the terminal 100 may release a relationship with a radio access point that has interacted with other secondary radio access points excluding the secondary radio access point 115 as an initial stage of the wireless connection re-establishment process.

In step 720, the terminal 100 may send a message requesting re-establishment of a wireless connection to the secondary radio access point 115. The message for requesting re-establishment of the wireless connection may be an RRCConnectionReestablishmentRequest message. In this case, the terminal 100 may omit the random access process prior to sending the wireless connection re-establishment request message.

The wireless connection re-establishment request message may include at least one of an identifier written by the secondary radio access point 115 to identify the terminal 100, an identifier of the secondary radio access point 115, and shortMAC-I for a secondary radio access point.

The identifier used by the secondary radio access point 115 to identify the terminal 100 may be C-RNTI. The secondary radio access point 115 identifier may be a physical cell identifier (PCI) or ECGI. The identifier used to identify the terminal 100 in the secondary radio access point 115 and the identifier of the secondary radio access point 115 may be paired and included in the request message.

The secondary radio access point 115 may retrieve the terminal context by using the ID of the terminal 100 and the ID of the secondary radio access point 115 contained in the request message. Additionally, the secondary radio access point 115 may be used to identify and query the terminal 100 using shortMAC-I for the secondary radio access point.

In step 730, the secondary radio access point 115 may recover terminal information in cooperation with the primary radio access point 110. In this case, the secondary radio access point 115 may send a message requesting terminal information to the primary radio access point 110. The primary radio access point 110 receiving the request may provide terminal information. Examples of terminal information provided by the requested primary radio access point 110 include terminal radio access capability information, AS configuration, AS context and radio resource management (RRM) configuration.

8 is a block diagram showing the configuration of a terminal according to an embodiment of the present invention.

Referring to FIG. 8, a terminal according to an embodiment of the present invention includes a transceiver 810, a multiplexing and demultiplexing device 820, various upper layer devices 830, a control message processing unit 840 and a control unit 850. can do.

The transceiver 810 receives data and control signals from a network, that is, a radio access point through a downlink channel, and transmits data and control signals to the network through an uplink channel.

The multiplexing and demultiplexing device 820 multiplexes the data generated by the upper layer device 830 or the control message processing unit 840 or demultiplexes the data received from the transceiver 810 to provide an appropriate upper layer device 830 or a control message. It serves to transfer to the processing unit 840.

The control message processing unit 840 is an RRC layer device and performs a necessary operation by processing a control message received from a network. The upper layer device 830 may be configured for each service, and may process data generated from a user service and transmit it to the multiplexing and demultiplexing device 820, or processing data transmitted from the multiplexing and demultiplexing device 820 Delivered to the layer service application.

The controller 850 controls the transceiver 810 and the multiplexing and demultiplexing device 820 according to information received through the transceiver 810. In addition, the controller 850 performs a function of controlling the terminal to increase efficiency by reducing the time for the terminal to transmit a new location registration request or reusing a wireless connection according to an embodiment of the present invention.

9 is a block diagram showing the configuration of a radio access point, for example, a base station according to an embodiment of the present invention. Referring to FIG. 9, a base station may include a transceiver 910, a multiplexing and demultiplexing device 920, an upper layer device 930, a control message processing unit 940, and a control unit 950.

The transceiver 910 transmits data and control signals to the terminal through a downlink channel, and receives data and control signals from the terminal through an uplink channel. In addition, the transceiver 910 also transmits and receives data and signals to and from other network entities connected through a wired network. In particular, the transceiver 910 transmits and receives necessary signals to and from a RAN control element, for example, an MME, according to an embodiment of the present invention.

The multiplexing and demultiplexing device 920 multiplexes the data generated by the upper layer device 930 or the control message processing unit 940 or demultiplexes the data received from the transceiver 910 to provide an appropriate upper layer device 930 or control message. It serves to transfer to the processing unit 940.

The control message processing unit 940 processes the control message transmitted by the terminal to take necessary actions, or generates a control message to be transmitted to the terminal and transmits it to a lower layer. The upper layer device 830 may be configured for each bearer, and the data transmitted from the S-GW or another base station is configured as an RLC PDU and transmitted to the multiplexing and demultiplexing device 920 or from the multiplexing and demultiplexing device 920 The delivered RLC PDU is configured as a PDCP SDU and delivered to the S-GW or other base station.

The controller 950 controls the transceiver 910 and the multiplexing and demultiplexing device 920 according to information received through the transceiver 910. In addition, the controller 950 releases the wireless connection of the terminal as soon as possible according to an embodiment of the present invention to shorten the time for the terminal to transmit a new location registration request, or to allow the terminal to reuse the wireless connection for a certain period of time. It performs the function of controlling to increase efficiency by maintaining it. Furthermore, control is performed so that the terminal can reuse the wireless connection with the secondary base station even in the process of handover and wireless connection re-establishment of the terminal.

In the above-described embodiments, all steps may be selectively performed or omitted. In addition, the steps in each embodiment do not necessarily have to occur in order, and may be reversed.

On the other hand, the embodiments of the present invention disclosed in the specification and drawings are only provided specific examples to easily explain the technical content of the present invention and to aid understanding of the present invention, and are not intended to limit the scope of the present invention. That is, it is apparent to those of ordinary skill in the art that other modifications based on the technical idea of the present invention can be implemented.

Claims (16)

In the method of the first base station of the communication system,
A second base station including a first identifier assigned by the first base station for the first base station to identify a terminal, a security-related capability of the terminal, and an aggregate maximum bit rate (AMBR) of the terminal used by the second base station Transmitting an additional request message to the second base station; And
When the addition of the second base station is approved by the second base station, the second base station sends a second base station addition approval message including a second identifier assigned by the second base station to identify the terminal. Including the step of receiving from the base station,
The first identifier and the second identifier are used to support dual connectivity of the terminal. The method of claim 1,
The method according to claim 1, wherein the second base station addition request message includes information on a bearer. The method of claim 2,
The information on the bearer, characterized in that it comprises an identifier of the bearer. The method of claim 2,
The information on the AMBR and the bearer is used for resource allocation to the terminal of the second base station. In the method of the second base station of the communication system,
A second base station including a first identifier assigned by the first base station for a first base station to identify a terminal, a security-related capability of the terminal, and an aggregate maximum bit rate (AMBR) of the terminal used by the second base station Receiving an additional request message from the first base station;
When the addition of the second base station is approved by the second base station, the second base station sends a second base station addition acknowledgment message including a second identifier assigned by the second base station to identify the terminal. Including the step of transmitting to the base station,
The first identifier and the second identifier are used to support dual connectivity of the terminal. The method of claim 5,
The method according to claim 1, wherein the second base station addition request message includes information on a bearer. According to claim 6
The information on the bearer, characterized in that it comprises an identifier of the bearer. The method of claim 6,
And allocating a resource to the terminal based on the AMBR and the bearer information. In the first base station of the communication system,
Transmitting and receiving unit for transmitting and receiving a signal; And
A second base station including a first identifier assigned by the first base station for the first base station to identify a terminal, a security-related capability of the terminal, and an aggregate maximum bit rate (AMBR) of the terminal used by the second base station When the addition request message is transmitted to the second base station, and the addition of the second base station is approved by the second base station, the second base station sends a second identifier assigned by the second base station to identify the terminal. And a control unit configured to receive an additional acknowledgment message for a second base station including, from the second base station,
The first base station, wherein the first identifier and the second identifier are used to support dual connectivity of a terminal. The method of claim 9,
The first base station, characterized in that the second base station addition request message includes information on a bearer. The method of claim 10,
The first base station, characterized in that the information on the bearer includes an identifier of the bearer. The method of claim 10,
The first base station, characterized in that the information on the AMBR and the bearer is used for resource allocation by the second base station to the terminal. In the second base station of the communication system,
Transmitting and receiving unit for transmitting and receiving a signal; And
A second base station including a first identifier assigned by the first base station for a first base station to identify a terminal, a security-related capability of the terminal, and an aggregate maximum bit rate (AMBR) of the terminal used by the second base station When an addition request message is received from the first base station, and the addition of a second base station is approved by the second base station, the second base station sends a second identifier assigned by the second base station to identify the terminal. And a control unit configured to transmit a second base station addition approval message including, to the first base station,
The second base station, wherein the first identifier and the second identifier are used to support dual connectivity of a terminal. The method of claim 13,
The second base station addition request message, characterized in that it includes information on a bearer. The method of claim 14,
The second base station, characterized in that the information on the bearer includes an identifier of the bearer. The method of claim 14,
The second base station, wherein the control unit is further configured to allocate resources to the terminal based on the AMBR and information on the bearer.

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