WO2015037937A1 - Method for searching for wireless lan and mobile terminal supporting same - Google Patents

Abstract

The present invention relates to a method for searching for a wireless LAN and to a mobile terminal supporting same, and a method for searching for a wireless LAN by a mobile terminal comprises the steps of: the mobile terminal receiving, from a base station, configuration parameters required for initiating search of a wireless LAN access point; the mobile terminal determining whether to initiate the search of a wireless LAN access point on the basis of the configuration parameters; and the mobile terminal initiating the search of a wireless LAN access point when the conditions required for the search initiation are satisfied.

Description

WLAN discovery method and mobile terminal supporting same

The present invention relates to a WLAN discovery method and a mobile terminal supporting the same.

A base station of a cellular network transmits and receives data with terminals included in a wide service area, that is, coverage. However, the cellular network base station has a wide coverage but a relatively low data transmission rate compared to a wireless LAN, and charges a data call fee to a user on a packet basis for transmitting and receiving data.

On the other hand, the WLAN has no data call charges charged to the user for packet transmission and reception, and the data transmission speed is high. However, since the coverage of the WLAN access point is small, the mobile terminal cannot freely transmit and receive data.

Because of these features of cellular networks and WLANs, mobile terminals that have access to both cellular networks and WLANs may search for an accessible WLAN access point before starting data communication, and do not have an accessible WLAN access point. If so, perform data communication over the cellular network.

However, in order to search for a WLAN access point, the mobile terminal must continuously power on the WLAN interface and periodically check whether it receives a WLAN signal from the WLAN access. Therefore, the load on the process from searching for access to the WLAN access point becomes large.

In recent years, in order to solve the problem of data explosion in mobile communication networks, data offloading through active linkage with a wireless LAN that can be freely used without permission using active bands has been actively studied. In addition, the 3rd Generation Partnership Project (3GPP) has established an interworking standard between cellular and WLAN. Therefore, even when using a wireless LAN, the subscriber's authentication is performed and the 3GPP network can be connected to attempt to solve the traffic congestion problem of the cellular network.

In addition, 3GPP LTE-A Release 12 standardizes cellular-WLAN interworking or small cell access to solve the explosion of data traffic in cellular systems. The most important problem to be solved in cellular-WLAN interworking or small cell access is to detect a WLAN or a small cell to be accessed and to establish a quick connection. Therefore, IEEE (Institute of Electrical and Electronics Engineers) 802.11 also defines a standard for faster access to a wireless LAN.

The QoS (Quality of Service) structure for WLAN interworking defined in the 3GPP standard provides a function provided in a 3GPP network using a WLAN as a wireless local area network (WLAN) 3GPP IP access function. That is, through WLAN interworking, traffic of the 3GPP network can be distributed through the WLAN network.

However, in order to access a WLAN network, a detection procedure is performed to obtain information necessary for access. Therefore, a connection delay occurs and power consumption occurs because a wireless packet (control frame) needs to be transmitted and received.

In addition, the number of WLAN access points existing within the cell radius of the base station is numerous. Therefore, in a situation in which the WLAN access point exists in a cell radius, when the mobile terminal is moving, the mobile terminal having two wireless modules, the wireless LAN and the cellular communication, searches for the WLAN while communicating with the cellular base station. Performs repetitive scanning for As a result, battery power of the mobile terminal is consumed. In addition, in the case of a mobile terminal having one wireless module, when communicating with a cellular base station or a wireless LAN access point, the mobile terminal should be changed to the corresponding wireless mode for communication. In other words, there is a problem that communication with the cellular base station is lost when the WLAN is searched because the cellular and the WLAN are not simultaneously communicated.

The foregoing example is disclosed in Korean Patent Publication No. 10-2008-0049894 (Name of the Invention: WLAN Searching Method and Apparatus in a Portable Terminal). In detail, when the WLAN is registered, a process of mapping cell information of a current location with the WLAN information and storing the cell information, and entering a mode that simultaneously supports a cellular network and a WLAN network while being connected to a cellular network, is currently accessing a cell. Comparing the stored cell information with the stored cell information; and searching for a WLAN using the WLAN information mapped to the stored cell information when the currently connected cell information matches the stored cell information. Doing.

Meanwhile, a base station of a cellular network transmits and receives data with terminals included in a wide service area. However, the data transmission speed in the boundary region of the cell becomes relatively lower than that in the center region of the cell. To compensate for this, a small cell is used, but when the same frequency is used between cells, an interference problem occurs, and a frequent handover occurs when the wireless communication device moves to the service area of the small cell. This causes frequent service disconnection.

Therefore, there is a need for a method that can perform a handover procedure while minimizing service disconnection.

In the context of the present invention, US registered patent US8279830 ("Method of performing")

handover for a dual transfer mode in a wireless mobile communication system "discloses a method in which a dual mode terminal receives information of a neighbor base station 200 and performs handover.

In addition, European Patent No. EP1744580 ("Dual-mode mobile terminal and method for handover of packet service call between different communication networks") discloses a method for providing communication including handover by mobile in a CDMA and WCDMA dual mode terminal. It is.

The present invention is to solve the above-mentioned problems of the prior art, and by receiving the mobility information of the mobile terminal from the base station, the mobile terminal determines the start of the WLAN access point search on its own during the movement, and more efficiently searching for the WLAN access point To provide a method.

Another object of the present invention is to provide a wireless communication system and method for reducing handover delay by using a wireless terminal capable of operating in a dual mode.

However, the technical problem to be achieved by the present embodiment is not limited to the technical problems as described above, and other technical problems may exist.

As a technical means for achieving the above-described technical problem, a wireless LAN discovery method of a mobile terminal according to an aspect of the present invention, the mobile terminal receiving a configuration parameter required for initiating a WLAN access point discovery from the base station; Determining, by the mobile terminal, whether to start searching for a WLAN access point based on a configuration parameter; The mobile terminal initiates the discovery of the WLAN access point when the conditions necessary for the discovery start are satisfied.

In addition, a mobile terminal according to another aspect of the present invention includes a memory for storing a program for performing WLAN discovery, one or more communication interface modules, and a processor for executing a program stored in the memory. At this time, the processor receives a setting parameter for initiating a WLAN access point discovery through the virtualization layer according to the execution of the program, and sets an operating parameter according to the received setting parameter.

In addition, the mobile terminal according to another aspect of the present invention includes a first communication module to operate as a primary communication module, and a second communication module to operate as a secondary communication module. Thus, when the first communication module is handed over from the source base station to the destination base station, the second communication module receives a data packet from the source base station.

In addition, a wireless network system for providing a wireless communication service to a mobile terminal according to another aspect of the present invention, a radio access network including a macro base station or a small cell base station, and a mobility management device and a core network gateway It includes a core network (core network) comprising a. At this time, the mobility management device is registered that the mobile terminal includes a primary communication module and a secondary communication module. In addition, when the primary communication module in the mobile terminal handovers from the source base station to the target base station, the secondary communication module receives a data packet from the source base station.

Further, a method for providing a wireless network service to a mobile terminal according to another aspect of the present invention, the method comprising: registering that the mobile terminal includes a primary communication module and a secondary communication module in the mobility management device of the wireless network system; Requesting packet redirection from the mobile terminal to the mobility management device; Instructing, by the mobility management device, the packet bypass to the core network gateway of the wireless network system; Setting, by the core network gateway, a bearer and a base station to deliver the packet to the secondary communication module according to the packet bypass request, and forwarding the packet to the set base station; And receiving, by the secondary communication module of the mobile terminal, the packet.

In addition, a method for handover by a mobile terminal in a wireless network system according to another aspect of the present invention includes the steps of: handing over from a source base station to a target base station by a main communication module of the mobile terminal; And simultaneously performing a handover by the primary communication module of the mobile terminal and receiving a data packet from the source base station by the secondary communication module.

According to any one of the above-described problem solving means of the present invention, the mobile terminal obtains the mobility information of the mobile terminal from the base station, it is possible to more efficiently wireless LAN search because the mobile terminal itself determines the start of the WLAN access point search during the movement Do.

In addition, according to any one of the problem solving means of the present invention, since the mobile terminal determines the start of the WLAN access point search while moving, it is possible to save battery power, and to reduce the traffic congestion of the mobile communication network.

In addition, according to any one of the problem solving means of the present invention, there is an effect that can reduce the handover delay of the wireless network system.

Further, according to any one of the problem solving means of the present invention, the mobile terminal can continue to maintain data communication with the source base station while performing a handover procedure with the target base station. Therefore, there is an effect of reducing the service disconnection that occurs when performing the handover.

In addition, according to any one of the problem solving means of the present invention, there is an effect that the configuration is simplified because two communication modules are used, and the data plane and the control plane are each different, and each communication module is independent There is an advantage to operate as.

In addition, according to any one of the problem solving means of the present invention, the two communication modules can operate independently and transmit and receive data independently, thus, it is effective to distribute the traffic by distributing the traffic of the user .

1 illustrates a system supporting a WLAN discovery method of a mobile terminal to which an embodiment of the present invention is applied.

FIG. 2 is a detailed diagram illustrating an information transmission process of a wireless network system supporting a WLAN discovery method of a mobile terminal according to an embodiment of the present invention.

3 is a detailed diagram illustrating a WLAN discovery method of a mobile terminal to which a trigger timer is applied in a WLAN discovery method of a mobile terminal according to an embodiment of the present invention.

4 is a configuration diagram illustrating a configuration of a mobile terminal supporting a WLAN discovery method according to an embodiment of the present invention.

5 is a detailed diagram illustrating a process of obtaining mobility information of a mobile terminal supporting a WLAN discovery method according to an embodiment of the present invention.

6 illustrates a structure of a wireless network system to which another embodiment of the present invention is applied.

7 illustrates a macro cell and a small cell to which another embodiment of the present invention is applied.

8 illustrates received signal strengths in a macro cell and a small cell to which another embodiment of the present invention is applied.

9 shows an example of a wireless communication system according to another embodiment of the present invention.

10 illustrates in more detail an example of a wireless communication system in accordance with another embodiment of the present invention.

11 illustrates a communication protocol structure for dual mode function registration in a wireless network system to which another embodiment of the present invention is applied.

12 illustrates a process of generating a handover delay in a wireless network system to which another embodiment of the present invention is applied.

FIG. 13 illustrates an example of continuously delivering a packet to a mobile terminal when performing handover according to another embodiment of the present invention.

14 illustrates a flow of a handover method without service disconnection in a wireless network system to which another embodiment of the present invention is applied.

15 is a flowchart illustrating a dual mode function registration method of a wireless network system to which another embodiment of the present invention is applied.

16 illustrates a flow of a dual mode communication method of a wireless network system to which another embodiment of the present invention is applied.

17 illustrates a flow of a dual mode communication start embodiment of a wireless network system to which another embodiment of the present invention is applied.

18 illustrates a flow of a dual mode communication termination embodiment of a wireless network system to which another embodiment of the present invention is applied.

19 illustrates a flow of an embodiment of detecting a handover and a heterogeneous small cell WLAN of a wireless network system to which another embodiment of the present invention is applied.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is "connected" to another part, this includes not only "directly connected" but also "electrically connected" with another element in between. . In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

Hereinafter, a wireless network system supporting a WLAN discovery method of a mobile terminal to which an embodiment of the present invention is applied will be described in detail with reference to FIG. 1.

1 illustrates a system supporting a WLAN discovery method of a mobile terminal to which an embodiment of the present invention is applied.

Referring to FIG. 1, a system supporting a WLAN discovery method of a mobile terminal to which an embodiment of the present invention is applied may include a user equipment (UE) 100 and a WLAN access point (WLAN AP) ( 200, an enhanced NodeB (RNB) or a Radio Network Controller (RNC) 300.

First, the mobile terminal 100 has two wireless modules of WLAN and cellular. The mobile terminal 100 is connected to the cellular system to perform communication, discovers the WLAN access point 200, accesses the WLAN through a connection procedure, and then transmits data through the WLAN. In this case, the communication with the WLAN uses a different radio frequency from the cellular system to which the mobile terminal 100 is connected, and searches for a different frequency band to perform a WLAN discovery for discovering the WLAN access point 200. Performs a WLAN scanning procedure.

Since the WLAN access point 200 generally uses radio resources in an unlicensed licensed band, the cost of data communication is lower than that of cellular communication. Accordingly, a data transmission / reception method using a wireless LAN may be used to process the transmission / reception data of the mobile terminal at low cost while reducing the load of the cellular system.

The base station 300 is a communication protocol, i.e., control, used by the base station 300 and the mobile terminal 100 to communicate with each other, which may be used when the mobile terminal 100 searches for accessible WLAN access points 200. It can be delivered using a communication protocol over a plane. In addition, the macro base station 300 may transmit the configuration parameters required for the start of the WLAN access point 200 to the mobile terminal 100. In this case, the configuration parameter includes a WLAN installation density, a WLAN service radius, a scanning mobility reference value, and the like.

FIG. 2 is a detailed diagram illustrating an information transmission process of a wireless network system supporting a WLAN discovery method of a mobile terminal according to an embodiment of the present invention.

Referring to FIG. 2, the information transmission process of a wireless network system supporting a method for searching for a WLAN access point 200 of a mobile terminal 100 according to an embodiment of the present invention may include: 200) receiving setting parameters necessary for starting a search; Determining whether to initiate discovery of the WLAN access point 200; And initiating a discovery of the WLAN access point 200.

First, in step S110 of receiving, by the mobile terminal, a configuration parameter necessary for initiating a WLAN access point discovery, the base station 300 transmits the configuration parameter necessary for initiating the discovery of the WLAN access point 200 to the mobile terminal 100. The mobile terminal 100 receives the configuration parameters required to start the search. In this case, configuration parameters required for initiation of discovery are WLAN installation density, WLAN service radius, scanning mobility reference value, and the like. Herein, the scanning mobility reference value means that scanning is not performed when the moving speed of the mobile terminal 100 is greater than the scanning mobility reference value, and the wireless LAN access point 200 of the wireless LAN access point 200 does not scan when the moving speed of the mobile terminal 100 becomes smaller than the scanning reference value. The reference value used to start the search. This reference value may be selected using a user's moving speed statistics.

Next, in step S120 of determining whether to start searching for a WLAN access point, the mobile terminal 100 determines whether to start searching for a WLAN access point 200 based on a configuration parameter received from the base station 300. At this time, the determination of whether to start searching for the wireless LAN access point 200 of the mobile terminal 100 measures the moving speed of the mobile terminal 100, and if the moving speed is greater than the scanning mobility reference value, delays the search for the wireless LAN access point 200. The search for the WLAN access point 200 is initiated when the moving speed of the mobile terminal 100 becomes smaller than the scanning mobility reference value.

As a method of measuring the moving speed of the mobile terminal 100, a method using Doppler Shift, a method of counting the number of Handovers, a method using the strength of a received signal, a method using GPS, etc. have.

First, a method using the Doppler shift uses that the frequency measured by the mobile terminal 100 is correlated according to the originally transmitted frequency and the moving speed, and is represented by Equation 1 below.

Equation 1

Where f is the observed frequency, c is the velocity of the wave, and v _r and v _s are the relative velocity of the receiver and the relative velocity of the source, respectively. In addition, f ₀ is a transmission frequency.

In addition, the method for searching for a WLAN according to an embodiment of the present invention does not consider the mobility of the base station 300. Therefore, Equation 1 may be summarized as Equation 2, and v _r may be measured using Equation 2. At this time, Equation 2 is as follows.

Equation 2

Meanwhile, the method for counting the number of handovers may use a handover performed when the mobile terminal 100 changes a cell. Specifically, the speed is measured by counting the number of handovers performed while the mobile station moves. In this case, when the number of handovers is large, it may be determined that the speed is high. In addition, since the handover is also related to the size of the cell, the number of handovers may be obtained by negotiating with the base station 300. In addition, when there is a small cell in the base station 300 that does not perform handover, the small cell found through the measurement may be counted. Alternatively, the moving speed may be measured by continuously measuring the time between the moment when the signal of the small cell is detected and the moment when the signal of the small cell is lost.

Alternatively, since all electromagnetic waves including a radio signal propagate, the signal is attenuated in inverse proportion to the distance, and thus the moving speed may be measured using the strength of the received signal. Since the strength of the signal decreases in inverse proportion to the square of the distance in free space, the distance of the base station 300 can be known by measuring the strength of the received signal. Therefore, the speed can be calculated by measuring the distance traveled through the measurement of the signal quality of successive base stations with time intervals.

Finally, in the case of using GPS, the reference for the moving speed is determined by the WLAN service radius. For example, if the wireless LAN service radius is 100m and the moving speed is 50km / h, it moves about 14m per second, so it passes the service radius in about 7 seconds. In this case, the search is meaningless because the connection cannot be made even after searching the WLAN. On the other hand, when moving at 5km / h, because it moves about 1.4m per second, it will stay within 70 seconds service radius. Therefore, the user can manually input a preference setting for how long to stay within the service radius to connect. In addition, the scanning mobility reference value may be set together with the WLAN installation density or the WLAN service radius information transmitted from the base station 300.

Subsequently, in step S130 of initiating a WLAN access point search, if the received parameter value satisfies a condition required for initiation of the discovery, the mobile terminal 100 may initiate discovery of the WLAN access point 200. However, if the received parameter value does not satisfy the conditions necessary for starting the search, the search is delayed.

On the other hand, the WLAN discovery method of the mobile terminal according to an embodiment of the present invention may utilize a trigger timer. At this time, the mobile terminal 100 may set the activation time of the trigger timer while starting the movement. The setting time of the trigger timer can be set to, for example, the time taken to the arrival point by calculating the moving distance and the speed of the moving means. Therefore, when the activation of the trigger timer expires, the mobile terminal 100 may compare the moving speed and the scanning mobility reference value.

In other words, while the trigger timer is activated, the mobile terminal 100 does not start searching for the WLAN access point 200. However, at the time of expiration of the trigger timer activity, if the moving speed of the mobile terminal 100 is smaller than the scanning mobility reference value, the mobile terminal 100 starts searching for the WLAN access point 200. Alternatively, when the trigger timer is expired, if the moving speed of the mobile terminal 100 is greater than the scanning mobility reference value, the trigger timer is activated after the set time and ends.

For example, when using public transportation, there may be a case where a WLAN search must be performed in a bus or a train. In general, in order to use public transportation, there is a time when there is no mobility because there is a waiting time for public transportation. According to an embodiment of the present invention, a trigger timer may be activated when a movement occurs. However, movement may continue upon expiration of trigger timer activity, and there may be cases where the speed of the moving object is greater than or equal to the mobility reference value. Accordingly, in the WLAN discovery method of a mobile terminal according to an embodiment of the present invention, when using a public transportation means in which mobility is not available and mobility is generated, the mobility reference value is checked for the first time after the trigger timer expires. Do not perform. Therefore, it is possible to perform a connection by finding a WLAN access point existing in the mobile body. Such an operation may allow a user to set a selection mode to perform a selective operation in the mobile terminal.

3 is a detailed diagram illustrating a WLAN discovery method of a mobile terminal to which a trigger timer is applied in a WLAN discovery method of a mobile terminal according to an embodiment of the present invention.

As shown in FIG. 3, the mobile terminal 100 sets the active time of the trigger timer while starting the movement (S201).

The trigger timer may be activated while the mobile terminal 100 starts moving. Thereafter, when the activation of the trigger timer expires, the mobile terminal 100 compares the moving speed of the mobile terminal 100 with the scanning mobility reference value. In this case, if the moving speed of the mobile terminal 100 is smaller than the scanning mobility reference value, the mobile terminal 100 starts searching for the WLAN access point 200 (S202).

On the other hand, when the activation of the trigger timer expires, if the moving speed of the mobile terminal 100 is greater than the scanning mobility reference value, the mobile terminal 100 may delay the discovery of the WLAN access point 200 (S204). In addition, when the discovery of the WLAN access point 200 is delayed due to the moving speed of the mobile terminal 100, the mobile terminal 100 may reactivate the expired trigger timer to the checkpoint active state.

When the trigger timer is activated again with the checkpoint active state, the trigger timer periodically has a checkpoint and compares the moving speed of the mobile terminal 100 and the scanning mobility reference value at each checkpoint to start searching for the WLAN access point 200. Determine whether or not.

In addition, if the mobile terminal 100 stops moving while the trigger timer is in operation, the trigger timer may be temporarily stopped (s204). At this time, the remaining activation time is recorded by the mobile terminal 100, the trigger timer may also be activated when the mobile terminal 100 starts moving again (s205). After that, when the movement of the mobile terminal 100 starts again, the trigger timer is activated after the remaining time and ends. When the trigger timer is activated after the set activation time and ends, the mobile terminal 100 starts searching for the WLAN access point 200 (S206).

Hereinafter, a configuration of a mobile terminal supporting a WLAN discovery method according to an embodiment of the present invention will be described in detail with reference to FIG. 4.

4 is a configuration diagram illustrating a configuration of a mobile terminal supporting a WLAN discovery method according to an embodiment of the present invention.

Referring to FIG. 4, the mobile terminal supporting the WLAN discovery method according to an embodiment of the present invention includes a virtualization layer 110, an LTE protocol layer 120, and a WiFi protocol layer 130. In this case, the virtualization layer 110 may include a mobility control unit 112.

First, the virtualization layer 110 requests the mobility information delivery to the LTE protocol layer 120, and receives the mobility information from the LTE protocol layer 120. In this case, the mobility information delivery request may be requested whenever necessary, or after a request is made, information may be received whenever a mobility event occurs. In this case, the virtualization layer 110 may communicate with another layer through a service access point (SAP), and the service access point may communicate through a message of a primitive type. In other words, the WLAN installation density, the WLAN service radius, and the scanning mobility reference value (scanning start moving speed) received as LTE parameters are transmitted to the virtualization layer 110 as a primitive message.

In addition, the virtualization layer 110 may include a mobility control unit 112. In this case, the mobility control unit 112 sets an operation parameter according to the parameter received from the LTE protocol layer 120.

Meanwhile, the mobile terminal supporting the WLAN discovery method according to an embodiment of the present invention may include a trigger timer in the mobility controller 112. In this case, the mobility control unit 112 may set the activation time of the trigger timer while starting the movement. In addition, the mobility controller 112 may instruct the WLAN search if the trigger timer satisfies the condition for the WLAN search. Alternatively, the WLAN discovery instruction may be performed by a separate device instead of the mobility control unit 112.

Next, the LTE protocol layer 120 may include a WLAN data link layer (LTE MAC) and a WLAN physical layer (LTE PHY). In this case, the LTE WLAN data link layer will mean a combination of Radio Resource Control, Radio Link Control, and Medium Access Control of 3GPP LTE.

The LTE protocol layer 120 may observe the mobility of the mobile terminal 100 and transmit the mobility information to the virtualization layer 110 whenever a move or stop event occurs.

In addition, the WiFi protocol layer may include a WLAN data link layer (WiFi MAC) and a WLAN physical layer (WiFi PHY). Here, the WiFi protocol layer receives a WLAN discovery command from the virtualization layer 110 and performs a WLAN discovery.

For reference, the components illustrated in FIG. 4 according to an embodiment of the present invention mean software components or hardware components such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and perform predetermined roles. .

However, 'components' are not meant to be limited to software or hardware, and each component may be configured to be in an addressable storage medium or may be configured to reproduce one or more processors.

Thus, as an example, a component may include components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, procedures, and subs. Routines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables.

Components and the functionality provided within those components may be combined into a smaller number of components or further separated into additional components.

5 is a detailed diagram illustrating a process of obtaining mobility information of a mobile terminal supporting a WLAN discovery method according to an embodiment of the present invention.

Referring to FIG. 5, in the process of obtaining mobility information of a mobile terminal supporting a WLAN discovery method according to an embodiment of the present invention, first, the virtualization layer 110 connects to the LTE protocol layer 120. It may be to request the mobility information required to start the search (s301). Subsequently, the LTE protocol layer 120 may transmit mobility information according to whether an event occurs to the virtualization layer 110 (S302). Next, the virtualization layer 110 determines whether the mobility information satisfies the WLAN discovery start condition, and if the WLAN discovery start condition is satisfied, the virtualization layer 110 instructs the WLAN protocol layer 130 to discover the WLAN. (S303). In addition, if the WLAN discovery is successful, the WiFi protocol layer 130 transmits the WLAN discovery success to the virtualization layer 110 (s304), and then the virtualization layer 110 is the LTE protocol layer 120 Performs a request to cancel mobility information transfer.

Meanwhile, in the step of the virtualization layer 110 requesting the mobility information transmission required for initiating the WLAN access point 200 to the LTE protocol layer 120 (s301), the mobility information delivery request may be requested whenever necessary, or once requested. In this case, information may be received whenever a mobility event occurs. The initiation of the mobility information transfer request is generated when the necessity of accessing the WLAN is generated. The WLAN access operation may be manually set by the user or automatically set by the mobility controller 112.

Subsequently, in step S302 of the LTE protocol layer 120 transferring mobility information according to whether an event occurs to the virtualization layer 110, the LTE protocol layer 120 receives a request for delivering mobility information from the virtualization layer 110. In addition, the mobility of the mobile terminal 100 may be observed. In addition, the mobility information may be delivered to the virtualization layer 110 whenever a move or stop event occurs.

In detail, when the mobile terminal 100 starts to move, the LTE protocol layer 120 may transfer the included mobile information such as a moving start time, a moving direction, and a moving speed to the virtualization layer 110. In addition, when a stop event occurs, the LTE protocol layer 120 delivers the stop information to the virtualization layer 110. In this case, the stop information may include a stop time or a time required to stop after the start of the movement, a moving direction, and the like. This operation can be continued whenever a move or stop event occurs. In addition, information such as WLAN installation density, WLAN service radius, and scanning mobility reference value (scanning start moving speed) received from the base station 300 may be transmitted together.

When the virtualization layer 110 receives mobility information from the LTE protocol layer 120, the mobility control unit 112 of the virtualization layer 110 starts searching for the WLAN access point 200 based on the mobility information transmitted from the LTE protocol. Determine whether or not.

In the WLAN search apparatus according to an embodiment of the present invention, the mobility control unit 112 may include a trigger timer. In this case, the mobility control unit 112 controls the operation of the trigger timer. In detail, the mobility controller 112 may activate the trigger timer when the mobile terminal 100 starts to move. Thereafter, when the activation of the trigger timer expires, the mobility controller 112 compares the movement speed of the mobile terminal 100 with the scanning mobility reference value. In this case, if the moving speed of the mobile terminal 100 is greater than the scanning mobility reference value, the virtualization layer 110 instructs the WiFi protocol layer 130 to detect the WLAN access point 200. However, if the moving speed of the mobile terminal 100 is less than the scanning mobility reference value, the virtualization layer 110 instructs the WiFi protocol layer 130 to search for the WLAN access point 200 (s303).

When the WiFi protocol layer 130 receives the WLAN access point 200 discovery instruction from the virtualization layer 110, the WiFi protocol layer 130 initiates discovery of the WLAN access point 200. In addition, if the WLAN discovery is successful, the WiFi protocol layer 130 may transmit whether the WLAN discovery succeeds to the virtualization layer 110 (S304).

Thereafter, the virtualization layer 110 receives the WLAN discovery success from the WiFi protocol layer 130, and then performs a request to cancel mobility information transmission to the LTE protocol layer 120 (s305).

6 illustrates a structure of a wireless network system to which another embodiment of the present invention is applied.

Referring to FIG. 6, the wireless network system 10 to which another embodiment of the present invention is applied may include a core network (CN) and a radio access network (RAN), which are central parts of the network. have. Here, the radio access network may be an access network connecting the mobile terminal 100 with a radio frequency (RF signal).

In addition, the wireless network system 10 according to the embodiment of the present invention may be configured to comply with various wireless communication standards. For example, the wireless network system 10 may conform to the Long Term Evolution-Advanced (LTE-A) standard, but is not limited thereto.

In addition, the core network CN may include a serving gateway (SGW) 400 and a mobile management entity (MME) 500. The mobility management device 500 is a core component of a core network CN that is in charge of various control functions to provide a wireless communication function of the mobile terminal 100. In addition, the SGW 400 is responsible for the function of a router for forwarding user data packets. Therefore, in the following description, the MME 500 is referred to as an MME or mobility management device, and the serving gateway 400 is referred to as an SGW or a core network gateway.

In addition, the core network CN may be connected to an external network or the Internet through elements such as a PGW (PDN Gateway: Packet Data Network Gateway, not shown). Through this, the mobile terminal 100 may be provided with cellular communication and various Internet services provided by the wireless network system 10.

In the exemplary embodiment of the present invention, the mobile terminal 100 is called by various names such as a mobile terminal, a portable terminal, a user device, a user equipment (UE), and the like, and can use a wireless communication function provided by the wireless network system 10 Refers to.

The mobile terminal 100 according to the embodiment of the present invention includes a first communication module 140M and a second communication module 150M, and may provide a dual mode communication function using the same. In addition, the apparatus may further include a first antenna 140A and a second antenna 150A, which are connected to each communication module, respectively, but are not limited thereto. That is, the mobile terminal 100 may include one or a plurality of antennas. In addition, the first communication module 140M and the second communication module 150M of the mobile terminal 100 may operate in different frequency bands (different frequency allocation (FA)).

Meanwhile, the radio access network (RAN) may include one or more base stations (eNBs) 300, and may further include a small base station (HeNB) 310. Here, the base station 300 may be a transmission / reception system including both a base station (BS), a relay station, and the like, and may be called various names such as a cellular network base station and a wireless base station. Therefore, although referred to herein as an evolved node B (eNodeB), it is not limited to the range indicated by the term. The base station 300 may be to service or cover a macro cell (MC). Therefore, in the present specification, the base station 300 will also be referred to as a macro base station 300.

Meanwhile, the small base station 310 is a small base station having a lower output and a smaller coverage than a macro base station. In the present invention, the small base station 310 may be referred to as a home eNodeB (Evolved Node B). It is not limited to the range. The small base station 310 services or covers a small cell (SC), and the small cell may be, for example, a femtocell. Therefore, in this specification, the small base station 310 will also be referred to as a small cell base station 310. However, in the present specification, the small base station 310 is not specified, and when referring to the base station, it may imply a base station 300 and 310 including the small base station 310.

In recent years, small cells have been increasingly employed because of the advantages of increasing the coverage of the wireless cellular network at a low cost and reducing the traffic load of the wireless cellular network. However, this requires a problem of solving an interference problem or a handover delay problem.

The mobile terminal 100 resets the connection to other base stations 300 and 310 with stronger signal strengths in order to maintain connection with the radio access network (RAN) as it moves. This is called handover. Meanwhile, service disconnection may occur due to the handover delay described with reference to FIG. 9. However, since the delay incurred in handover with the small cell is longer than in the handover between the macro cells, the possibility of service disconnection may be higher in the handover with the small cell.

Next, the macro cell and the small cell will be described in more detail with reference to FIGS. 7 and 8.

FIG. 7 illustrates a macro cell and a small cell to which another embodiment of the present invention is applied, and FIG. 8 illustrates received signal strengths in the macro cell and the small cell.

As shown in FIG. 7, the mobile terminal 100 may transmit / receive a radio signal with the base station 300 and the small base station 310. The small cell SC has a smaller coverage than the macro cell MC, and as shown, when the small cell SC exists in the macro cell MC (overlapping), the wireless network system 10 includes the macro cell. Instead of the MC, the small cell SC may provide a wireless communication service to the mobile terminal 100 (off-load), thereby reducing the traffic load of the macro cell MC.

In addition, when the macro cell MC and the small cell SC are configured to overlap each other, the mobile terminal 100 may receive data simultaneously from both sides, or may select and receive only one of them. In addition, the macro cell MC and the small cell SC may be linked to each other through an interface that interworks between the macro cell MC such as the X2 interface.

Meanwhile, the macro cell MC and the small cell SC may be configured to use different carrier frequencies or may be configured to use the same carrier frequency. Both methods have advantages and disadvantages.

For example, when one frequency is used by the macro cell MC and the other is used by the small cell SC as in the former, the interference problem in which two carrier frequencies affect each other is less severe. There is this. However, in order to detect the small cell SC using a different frequency, a service break with the macro cell MC may occur, a service break occurs even during the handover process, and frequency efficiency is also lowered.

On the other hand, when the CA (Carrier Aggregation) technology macro cell (MC) and the small cell (SC) use the two frequencies together, the operation is complicated, but it is easy to detect the cell and efficiently It has the advantage of being available.

FIG. 8 is a diagram illustrating a radio wave transmission / reception distance between the macro cell MC and the small cell SC, and shows that the strength of the received signal decreases according to the position of the mobile terminal 100.

Referring to FIG. 8, the P1 section represents the strength of the downlink signal received from the macro base station 300, and the P2 section represents the strength of the downlink signal received from the small base station 310. In addition, the P3 section represents the strength of the uplink signal received by the macro base station 300, and the P4 section represents the strength of the uplink signal received by the small base station 310.

As shown in FIG. 8, due to the attenuation according to the distance of the radio signal, the data transmission rate is relatively lower than the center region of the cell as the cell is moved toward the boundary region. Accordingly, as described above, when the mobile terminal 100 moves away from the base station currently being serviced according to the movement, the mobile terminal 100 hands over to another base station having better signal strength.

In addition, as described above, if the small base station 310 that can be constructed at a low cost instead of the expensive macro base station 300 is constructed, it is possible to increase the overall coverage.

In general, when constructing a base station, the service coverage of a cell provided by each base station is overlapped. In this case, since the transmission distance of the small cell SC is shorter than that of the macro cell MC, the method of detecting the small cell SC should be different from that of the macro cell MC search method. Therefore, when the small cell SC is searched for and handed over in the same manner as the handover between the macro cells MC, service disconnection may occur.

Service interruption due to the above-described handover may occur more frequently, especially when using a moving object such as a car or a high-speed train. Accordingly, when the user of the mobile terminal 100 wants to be provided with a wireless communication service by riding on a mobile moving at a high speed, as in the example of the embodiment shown in FIG. There is a problem of difficulty.

9 and 10 show an example of a wireless network system according to another embodiment of the present invention.

Referring to FIG. 9, in a wireless network system to which another embodiment of the present invention is applied, cellular mobile communication such as LTE may be performed by establishing an on-board mobile communication terminal (On Board Terminal) in a mobile chain railway environment. . In this case, the mobile terminal 100 is a next-generation mobile communication terminal, it may be used to provide a WLAN service, such as WiFi to the passenger. That is, the mobile terminal 100 to which another embodiment of the present invention is applied may be used to provide WiFi, which is a heterogeneous wireless network, as a next-generation mobile communication terminal connecting to a cellular network (RAN). To this end, the mobile terminal 100 may be connected to one or more WiFi access points by wire, and the wireless LAN access point 200 may exchange a wireless communication signal with the WiFi terminal 210. In this case, the radio access network (RAN) and the core network (CN) to which the mobile terminal 100 connects are as described with reference to FIG. 6, and thus, the user's WiFi terminal 210 may be connected to the Internet.

In detail, the WiFi terminal 210 may transmit a packet by connecting to the WLAN access point 200 accessible from its location. In this case, the WiFi terminal 210 may transmit the packets transmitted from the WLAN access point 200 to the Internet in the same manner as the mobile terminal 100 performs cellular communication with the cellular base station. The same is true for packets in the opposite direction. That is, the packet is transmitted from the cellular base station 300 to the mobile terminal 100, and the mobile terminal 100 transmits it to the wireless LAN access point 200 connected thereto by wire. Subsequently, the WLAN access point 200 transmits the packet to the WiFi terminal 210 in a WLAN manner, so that the WiFi terminal 210 may receive the packet from the Internet network.

However, as described above, as the moving object moves at a high speed, the distance between the mobile terminal 100 and the source base station 300S serving cellular communication is rapidly moving away. Accordingly, the mobile terminal 100 is moved away from one source base station 300S and the radio signal quality is poor and moves toward the base station serving the adjacent cellular communication. Then, when the radio signal quality of the neighboring base station improves, a handover procedure is performed to establish a connection to the neighboring base station.

Hereinafter, in the specification of the present invention, the mobile station 100 handovers the base stations 300 and 310 which are currently being provided with the source eNB or the source base station 300S to the neighboring base station 300 to newly receive the service. 310 is referred to as a target eNB or a target base station 300T.

As described above, it takes a certain time to complete the handover procedure, the service disconnection may occur if the moving object moves at too fast. Accordingly, to solve this problem, the mobile terminal 100 to which the embodiment of the present invention is applied includes two communication modules 140M and 150M and antennas 140A and 150A respectively installed at the front and the rear of the vehicle. Can be.

Accordingly, the mobile terminal 100 performs a handover to the target base station 300T through the second antenna 150A installed at the front of the vehicle and at the same time through the first antenna 140A installed at the rear of the vehicle. Data may be exchanged with the source base station 300S.

This configuration has the advantage that it is possible to transmit and receive data while performing a handover, to provide a wireless LAN service without interruption of service to the user's WiFi terminal 210.

10 shows an example of a protocol layer of the first communication module 140M and the second communication module 150M to which another embodiment of the present invention is applied.

As shown in FIG. 10, the mobile terminal 100 may include two or more communication module sources, and perform handover while simultaneously communicating with the source base station 300S or the target base station 300T. . In this case, the mobile terminal 100 may perform communication using a data plane of the source base station 300S and the first communication module 140M. In addition, the mobile terminal 100 may perform communication using a control plane of the target base station 300T and the second communication module 150M.

In addition, the second communication module 150M of the mobile terminal 100 may transmit / receive a message for performing a control plane handover procedure with the target base station 300T through the antenna 150A mounted at the front of the train. . At the same time, the first communication module 140M may transmit and receive data plane data with the source base station 300S through the antenna 140A mounted at the rear of the train.

In this case, the data plane and the control plane may each include a physical (PHY) layer and a medium access control (MAC) layer corresponding to the first and second layers L1 and L2 of the OSI protocol stack, respectively. have. In addition, the second to third layers L2 and L3 of the data plane include an Internet Protocol (IP), a Packet Data Convergence Protocol (PDCP), and a Radio Link Control (RLC) layer. Control (RRC), PDCP, and RLC layer. In addition, the data plane includes upper layers for data communication, and in the case of the control plane, may include a non-access stratum (NAS) layer (see FIG. 11).

Meanwhile, as described above, in order to simultaneously use the first communication module 140M and the second communication module 150M, the dual mode of the mobile terminal 100 may be connected to the mobility management device 500 of the core network CN. mode) You must register the function.

11 illustrates a communication protocol structure for dual mode function registration in a wireless network system to which another embodiment of the present invention is applied.

According to the embodiment of the present invention, the mobile terminal 100 having two or more communication modules 140M and 150M should change the path of the IP packet in the network according to the communication situation of the mobile terminal 100.

Therefore, first, the network CN should recognize that the mobile terminal 100 is a terminal having two or more communication modules 140M and 150M. Capability negotiation of the mobile terminal 100 is performed between non-access stratum (NAS) layers.

11 shows a protocol structure diagram for communicating with the NAS layer. The mobile terminal 100 communicates with the base station 300 in the control plane (C2) of the air interface, the base station 300 is an interface (C3) consisting of a mobility management device 500 existing in the network (CN) and usually wired Communicate via.

NAS is a functional layer existing between the core network (CN) and the mobile terminal 100 in the protocol stack of the wireless network system 10, such as UMTS or LTE. The NAS manages the communication session setup and is responsible for maintaining communication even when the mobile terminal 100 moves. In addition, the NAS is a functional layer corresponding to an AS (Access Stratum) layer responsible for data transmission and reception. The AS transparents the radio access network (RAN) between the mobile terminal 100 and the MME 500 as shown, in contrast to the explicit communication between the mobile terminal 100 and the radio access network (RAN). (C1).

When performing initial registration with the NAS, when the mobile terminal 100 is a terminal having a communication capability using two or more communication modules 140M and 150M, the two communication modules 140M and 150M respectively perform a registration procedure. . It can also negotiate with the NAS which communication modules will be bound and operated. And, it is possible to negotiate which of the two communication modules is the primary and which is the secondary.

12 illustrates a process of generating a handover delay in a wireless network system to which another embodiment of the present invention is applied.

Referring to FIG. 12, when the signal quality of the source base station 300S is lower than a certain reference point or less, the mobile terminal 100 measures and reports the signal quality of the source base station 300S and the neighboring base station 200 (S401). ).

Subsequently, the source base station 300S looks at the reported content and decides to perform a handover (S402).

In addition, the source base station 300S performs a handover procedure for the target base station 300T and the mobile terminal 100 (S403, S404), and performs a handover to the mobile terminal 100 to the target base station 300T. To command (S405).

The mobile terminal 100 switches the radio link from the cell of the source base station 300S to the cell of the destination base station 300T (S406). From this step, the mobile terminal 100 cannot receive a packet transmitted from the source base station 300S.

Subsequently, the source base station 300S transmits the state of the mobile terminal 100 which it has to the target base station 300T (S407).

Next, the source base station 300S may transfer data not transmitted among the packets stored to be transmitted to the mobile terminal 100 to the destination base station 300T (S408). The target base station 300T stores the packets transmitted from the source base station 300S in a buffer (S409).

Next, the mobile terminal 100 reports that the connection is completed to the target base station 300T (S210).

Next, the mobile terminal 100 reports the number of packets correctly received at the source base station 300S to the target base station 300T (S411).

Subsequently, the target base station 300T transmits the packets that are not received by the mobile terminal 100 among the packets stored in the buffer to the mobile terminal 100 (S412).

As described above, when the mobile terminal 100 performs a handover that needs to change the base station 300 while moving, service disconnection may occur (from S405 to S412). In addition, since the handover occurs more frequently in a moving object such as a high-speed train moving at a higher speed as in the above-described embodiment, service disconnection may occur more frequently.

FIG. 13 illustrates an example of continuously delivering a packet to a mobile terminal when performing handover according to another embodiment of the present invention. The figure shows an example of delivering packets 1, 2, 3, 4, 5 from the source base station 300S to the mobile terminal 100 and continuing to deliver the packet when the handover is performed.

First, the packet number 1 is a case where the source base station 300S delivers the packet to the mobile terminal 100 without error in the initial transmission (S501).

Packet number 2 is a case in which the source base station 300S fails to transmit in the initial transmission to the mobile terminal 100 (S502), and retransmits without error (S503).

Packet number 3 is a case in which an error occurs in both initial transmission (S504) and retransmission (S505), so that the source base station 300S does not successfully transmit the packet to the mobile terminal 100.

Packet number 4 is a case where the source base station 300S successfully transmits the packet in the initial transmission to the mobile terminal 100 (S506).

Packet number 5 has not started transmission yet. As described above, the handover may be started in the state that some packets have not yet been delivered from the source base station 300S to the mobile terminal 100.

Therefore, during the handover, the source base station 300S may transmit packets of packet numbers 2, 3, and 5 that are not known whether the mobile terminal 100 has successfully received the packet to the target base station 300T (S507).

Subsequently, after successfully performing the handover, the mobile terminal 100 reports the received packets 1, 2, and 4 and the unsuccessful packet 3 to the destination base station 300T without error (S508).

Accordingly, the target base station 300T may transmit the packet 3 that received the NACK and the packet 5 that did not start transmission to the mobile terminal 100 at the time of handover to the mobile terminal 100. (S509, S510).

14 illustrates a flow of a handover method without service disconnection in a wireless network system to which another embodiment of the present invention is applied.

First, when the signal quality of the source base station 300S is not lower than a certain reference point, the mobile terminal 100 measures the signal quality of the source base station 300S and the neighboring base station 300 and reports it to the source base station 300S. (S601).

Thereafter, the source base station 300S determines to perform the handover based on the reported contents (S602).

Subsequently, the source base station 300S performs a handover procedure for the target base station 300T and the mobile terminal 100 (S603 and S604), and performs a handover to the target terminal 300T to the mobile terminal 100. To order (S605).

In addition, the source base station 300S transmits the state of the mobile terminal 100 that it has to the target base station 300T (S606).

In addition, the source base station 300S transmits data that has not been transmitted among the packets stored to the mobile terminal 100 to the target base station 300T (S608), and the target base station 300T is the source base station 300S. The delivered packets are stored in a buffer (S609).

The above step is the same as the prior art of FIG. However, in the prior art, the mobile terminal 100 could not receive a packet transmitted from the source base station 300S during handover, but in the embodiment of the present invention, while the above-described steps S606 to S608 are performed, the source Packets in the buffer of the base station 300S may be continuously delivered to the mobile terminal 100 (S607). Thus, as shown, the mobile terminal 100 may not experience service disruption.

Subsequently, the mobile terminal 100 reports that the connection is completed to the target base station 300T (S610).

In addition, the mobile terminal 100 reports the number of packets correctly received from the source base station 300S to the destination base station 300T (S611). At this time, in step S607, the number of correctly received packets is included and reported.

Subsequently, the mobile terminal 100 changes its data plane setting from communication with the source base station 300S to communication with the target base station 300T (S612).

The target base station 300T transmits the packets that are not received by the mobile terminal 100 among the packets stored in its buffer to the mobile terminal 100 (S613).

As described above, if the data plane continues to receive data packets from the source base station 300S while the control plane of the mobile terminal 100 performs the handover, the mobile terminal 100 should include two or more communication modules. will be.

Therefore, the mobile terminal 100 according to the embodiment of the present invention may have a dual mode capability. For example, as in the above-described embodiment, the second communication module 150M of the mobile terminal 100 transmits and receives a message for performing a control plane handover procedure with the target base station 300T, and at the same time, the first communication module. 140M may transmit and receive data plane data with the source base station 300S.

However, in order to use two or more communication modules at the same time, the mobile terminal 100 should inform the MME 500 that the mobile terminal 100 has a dual mode function. This will be described with reference to FIG. 15.

15 is a flowchart illustrating a dual mode function registration method of a wireless network system to which another embodiment of the present invention is applied.

FIG. 15 is an embodiment illustrating negotiation of a dual mode function in an attach procedure with an NAS layer of the MME 500.

First, the mobile terminal 100 requests registration while notifying the MME 500 that the terminal has a dual mode function (S701). In this case, the mobile terminal 100 may inform the MME 500 which communication module to bind with. That is, the current communication module is the primary communication module and informs the ID of the second communication module.

For example, when the current main communication module of the mobile terminal 100 is the first communication module 140M, the registration procedure is performed by the first communication module 140M, and the ID of the second communication module 150M is determined. Inform.

On the other hand, the MME 500 allows the registration (S703) or rejects (S704). If the registration is allowed, the mobile terminal 100 sends a registration completion message to the MME 500 (S703).

Hereinafter, a method in which a secondary communication module (eg, the second communication module 150M) instead receives a data packet to be received by the main communication module (eg, the first communication module 140M) through FIGS. 16 to 19, and such a method. Describe how to terminate data packet redirection. The description includes handovers to homogeneous small cells (SCs) and heterogeneous small cells (eg, WiFi networks).

16 illustrates a flow of a dual mode communication method of a wireless network system to which another embodiment of the present invention is applied.

The main communication module (eg, 140M) of the mobile terminal 100 registers the dual mode function in the MME 500 as in the method described with reference to FIG. 15 (S810).

Subsequently, the main communication module (eg, 140M) of the mobile terminal 100 requests packet bypass to the MME 500 (S812). This may be used in situations such as handover as described above.

Subsequently, the MME 500 instructs the SGW 400 to bypass the packet (S813).

The SGW 400 sets up a base station 300 and a bearer for the secondary communication module (eg, 150M) (S814).

The SGW 400 transmits a packet to be transmitted to the secondary communication module (eg, 150M) of the mobile terminal 100 to the base station 300 that communicates with the secondary communication module (eg, 150M) (S815).

The base station 300 transmits a packet to a secondary communication module (eg, 150M) of the mobile terminal 100 (S816).

Once again, as described above, the mobile terminal 100 negotiates and registers a dual mode function with the NAS located in the MME 500 (S810). After such registration, the communication of the first communication module 140M and the second communication module 150M is bound.

In such an environment, if a situation in which a packet should be received by the second communication module 150M occurs as in the above-described handover embodiment, a packet redirection request is made (S812).

Since the MME 500 is an entity in charge of control such as mobility management, the MME 500 instructs the packet detour to the SGW 400 in order to bypass the packet (S813).

The SGW 400 sets up a bearer with the base station 300 to deliver the packet to the second communication module 150M (S814). At this time, the base station 300 to which the bearer is set may be a base station 300 that is different from the base station 300 to which the first communication module 140M is connected and communicating.

The packet transmitted to the first communication module 140M may be transmitted to the second communication module 150M through the set bearer (S815).

The base station 300 transmits the received packet to the wireless interface to the communication second communication module 150M (S816).

Since the mobile terminal 100 has the same IP layer structure, even if the packet arrives at different communication modules from the lower end of the mobile communication module, the IP packet is composed of the same packet. Accordingly, the mobile terminal 100 may perform a communication operation and receive and process the detoured packet.

17 illustrates a flow of a dual mode communication start embodiment of a wireless network system to which another embodiment of the present invention is applied. 17 shows an embodiment when handing over to the small cell SC.

First, the small base station 310 usable in the mobile terminal 100 is searched for (S811).

The main communication module (eg, 140M) of the mobile terminal 100 requests packet bypass to the MME 300 (S812).

The MME 500 instructs the SGW 400 to bypass the packet (S813).

The SGW 400 sets up a bearer with the small base station 310 (S814).

The SGW 400 transmits a packet to be transmitted to the secondary communication module (eg, 150M) of the mobile terminal 100 to the small base station 310 (S815).

The small base station 310 transmits the packet to the secondary communication module (eg, 150M) of the mobile terminal 100 (S816).

Once again, the drawing illustrates an embodiment of a method of communicating using two communication modules when the mobile terminal 100 moves to a small cell (SC) network using the present invention.

The small cell SC is found (S811). The small cell (SC) found at this time may be a femtocell that is homogeneous or a heterogeneous WLAN.

A packet path change (packet bypass) request is performed (S812). The packet path change request is received by the base station 300 and delivered to the MME 500. This packet path change request can be included in the handover signal exchange.

The MME 500 instructs the SGW 400 to deliver a packet delivered to the mobile terminal 100 to the newly discovered small cell SC (S813).

The SGW 400 sets up a bearer for delivering the packet together with the found small cell SC (S814).

The packet is delivered to the newly discovered small cell SC to the configured bearer (S815).

The packet received by the small cell SC is transferred to the communication second communication module 150M of the mobile terminal 100 (S816).

18 illustrates a flow of a dual mode communication termination embodiment of a wireless network system to which another embodiment of the present invention is applied.

The mobile terminal 100 tries to move from the small cell base station 310 to the macro cell base station 300 (S821).

The main communication module (eg, 140M) of the mobile terminal 100 requests the packet bypass release to the MME 500 (S822).

The MME 500 instructs the SGW 400 to release the packet detour (S823).

The SGW 400 releases the bearer that has been connected to the secondary communication module (eg, 150M) of the mobile terminal 100 via the small base station 310 (S824).

The SGW 400 transmits a packet to be transmitted to the main communication module (eg, 140M) of the mobile terminal 100 to the macro base station 300 (S825).

The macro base station 300 transmits the packet to the main communication module (eg, 140M) of the mobile terminal 100 (S826).

Referring again to the drawings, when the mobile terminal 100 moves from the small cell (SC) network to the macro base station 300 using the present invention, an embodiment showing a method for communicating using two communication modules to be.

It is found out of the service area of the small cell (SC) network (S821).

A packet forwarding release request is performed (S822). At this time, the release request may be performed as part of the handover step.

The MME 500 instructs the SGW 400 to release the packet forwarding (S823).

The SGW 400 releases the bearer set up to deliver the packet to the small cell SC (S824), and forwards the packet to the base station 300 (S825). Step S825 may be performed at the same time as step S824 because the bearer previously established may be used as it is.

The packet received by the base station 300 is transmitted to the first communication module 140M of the mobile terminal 100 (S826).

FIG. 19 is a flowchart illustrating an embodiment of detecting a handover and a heterogeneous small cell (WiFi) of a wireless network system to which another embodiment of the present invention is applied.

When the signal quality of the source base station 300S is lower than a certain reference point or less, the mobile terminal 100 measures and reports the signal quality of the source base station 300S and the peripheral base station 300 (S901).

After the source base station 300S determines the handover based on the reported contents (S902), the source base station 300S performs a handover procedure for the target base station 300T and the mobile terminal 100 (S903 and S904) and the mobile terminal 100. RRC connection reconfiguration command to perform a handover to the target base station 300T (S905).

The status of the mobile terminal 100 possessed by the source base station 300S is transferred in a status transfer message (S906).

After a new connection is established with the target base station 300T (RRC Connection Configuration Complete), information of a heterogeneous small cell SC to be detected is received (S907).

The heterogeneous small cell SC may be detected and a connection may be established by performing passive scanning or active scanning based on the received heterogeneous small cell SC information (S908).

The above is summarized as follows.

One of the objects according to an embodiment of the present invention is to enable the mobile terminal 100 to perform a handover procedure while minimizing service interruption when performing a handover by movement.

Accordingly, in the wireless communication method according to the embodiment of the present invention, the mobile communication terminal 100 includes dual communication modules 140M and 150M, and handovers to one of two communication modules (for example, 140M). When performing, another communication module (eg 150M) receives data. Data reception after the handover may be performed in two (140M, 150M) or one (eg, 140M).

The dual communication modules 140M and 150M of the mobile terminal 100 according to an embodiment of the present invention may be connected to the source base station 300S and the target base station 300T by using the respective antennas 140A and 150A located at spatial distances. Can communicate with each other. At this time, the first communication module 140M performs a handover procedure with the target base station 300T, and the second communication module 150M communicates with the source base station 300S so that there is no service interruption.

A mobile terminal to which an embodiment of the present invention is applied may include a first communication module that operates as a primary communication module and a second communication module that operates as a secondary communication module. Therefore, when the first communication module performs control communication, the second communication module may perform data communication. Alternatively, when the first communication module performs a handover from the source base station to the target base station, the second communication module may receive a data packet from the source base station instead of the first communication module.

Alternatively, when the first communication module performs a packet redirection request and cancellation, and the first communication module performs a packet bypass request, the second communication module may receive a data packet instead of the first communication module.

Alternatively, the mobile terminal to which the embodiment of the present invention is applied includes a first antenna used for communication between the first communication module and the source base station and the target base station, and a second antenna used for communication between the second communication module and the source base station. Can be configured. In this case, the first antenna and the second antenna may be spaced apart from each other. Alternatively, the first antenna and the second antenna may be installed outside the mobile terminal.

The first communication module and the second communication module included in the mobile terminal to which the embodiment of the present invention is applied can use different frequency bands.

In addition, a mobile terminal to which an embodiment of the present invention is applied may register a primary communication module and a secondary communication module through non-access stratum (NAS) communication with a core network.

The first communication module included in the mobile terminal to which the embodiment of the present invention is applied requests a packet redirection to the second communication module from the core network, and the core network may forward the packet to the second communication module according to the request. Bearers and base stations can be configured.

A wireless communication system providing a wireless communication service to a mobile terminal to which an embodiment of the present invention is applied includes a radio access network including a macro base station or a small cell base station, and a mobility management device and a core network gateway. It may be configured to include a core network (core network). At this time, the mobility management device is registered that the mobile terminal includes the primary communication module and the secondary communication module, the mobile terminal is the primary communication module when the handover (handover) from the source base station to the target base station, the secondary communication module is the primary The data packet may be received from the source base station instead of the communication module.

In addition, the mobility management device instructs the core network gateway to bypass the packet when the mobile terminal requests packet redirection, and the core network gateway bears a bearer for delivering the packet to the secondary communication module of the mobile terminal according to the packet bypass request. ) And a base station, and can transmit a packet to the set base station.

Alternatively, the mobility management entity instructs the core network gateway to release the packet bypass when the mobile terminal requests the packet bypass release, and the core network gateway forwards the packet to the secondary communication module of the mobile terminal according to the packet bypass release request. And release the base station and forward the packet to the base station communicating with the primary communication module of the mobile terminal.

Using a wireless communication system to which an embodiment of the present invention is applied, a method of providing a wireless communication service to a mobile terminal including a primary communication module and a secondary communication module may include packet redirection to a mobility management device. Requesting; Instructing, by the mobility management device, the packet bypass to the core network gateway of the wireless communication system; Setting, by the core network gateway, a bearer and a base station to deliver the packet to the secondary communication module according to the packet bypass request, and forwarding the packet to the set base station; And receiving, by the secondary communication module of the mobile terminal, the packet.

Alternatively, a method of providing a wireless communication service to a mobile terminal including a primary communication module and a secondary communication module by using a wireless communication system to which an embodiment of the present invention is applied may be performed by the mobile terminal to a mobility management apparatus of the wireless communication system. The method may further include registering that the communication module and the sub communication module are included.

Using a wireless communication system to which an embodiment of the present invention is applied, a method of providing a wireless communication service to a mobile terminal including a primary communication module and a secondary communication module may include requesting, by the mobile terminal, a packet bypass release from the mobility management device. The mobility management device instructing the core network gateway of the wireless communication system to release packet bypass; The core network releasing a bearer and a base station that have delivered packets to the secondary communication module of the mobile terminal according to the packet bypass release request, and forwarding the packet to the base station communicating with the primary communication module of the mobile terminal; And receiving, by the main communication module of the mobile terminal, the packet.

Alternatively, the method may further include performing a handover by the primary communication module of the mobile terminal from the source base station to the target base station, and receiving a data packet from the source base station by the secondary communication module of the mobile terminal at the same time as the handover.

Meanwhile, the performing of the handover by the main communication module of the mobile terminal may include requesting packet redirection to the mobility management device.

In a wireless communication system to which an embodiment of the present invention is applied, a method for handover by a mobile terminal is performed by a main communication module of the mobile terminal handovering from a source base station to a target base station and at the same time as handover. The module may further comprise receiving a data packet from a source base station.

Alternatively, the performing of the handover by the main communication module of the mobile terminal may include requesting packet redirection to the mobility management entity.

One embodiment of the present invention can also be implemented in the form of a recording medium containing instructions executable by a computer, such as a program module executed by the computer. Computer readable media can be any available media that can be accessed by a computer and includes both volatile and nonvolatile media, removable and non-removable media. In addition, computer readable media may include both computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Communication media typically includes computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave, or other transmission mechanism, and includes any information delivery media.

Although the methods and systems of the present invention have been described in connection with specific embodiments, some or all of their components or operations may be implemented using a computer system having a general purpose hardware architecture.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Claims (14)

1. In a wireless LAN discovery method of a mobile terminal,

   Receiving, by the mobile terminal, configuration parameters required for initiating a WLAN access point search from a base station;

   Determining, by the mobile terminal, whether to start a WLAN access point search based on the configuration parameter; And

   And initiating a discovery of a WLAN access point by the mobile terminal when a condition necessary for initiation of discovery is satisfied.
2. The method of claim 1,

   The configuration parameter required for initiation of discovery is one or more of WLAN installation density, WLAN service radius, and scanning mobility reference value.
3. The method of claim 2,

   The scanning mobility reference value is a reference value used to initiate discovery of a WLAN access point, and the reference value is selected using a user's moving speed statistical value.
4. The method of claim 1,

   Determining whether to start the WLAN access point search is

   Delaying discovery of a WLAN access point if the moving speed of the mobile terminal is greater than the scanning mobility reference value;

   And initiating a WLAN access point search when the moving speed of the mobile terminal is less than the reference value.
5. The method of claim 4, wherein

   Determining whether to start searching for the WLAN access point is

   Activating a trigger timer when the mobile terminal starts to move;

   The trigger timer is

   And activating the mobile terminal when the mobile terminal starts moving, and when the activation of the trigger timer expires, the mobile terminal comparing the moving speed of the mobile terminal with a scanning mobility reference value.
6. The method of claim 4, wherein

   Determining whether to start searching for the WLAN access point is

   The base station further comprises the step of transmitting the information of the trigger timer for activating the discovery start time of the mobile terminal to the mobile terminal.
7. The method of claim 4, wherein

   If the moving speed of the mobile terminal is greater than the scanning mobility reference value, delaying the WLAN access point discovery

   Further comprising measuring a moving speed,

   The method of measuring the moving speed, using a Doppler shift method, the method of counting the number of handovers, the method of using the strength of the received signal and the method of using the WLAN using any one of the methods.
8. The method of claim 4, wherein

   Determining whether to start searching for the WLAN access point is

   Activating a trigger timer when the mobile terminal starts to move;

   The trigger timer is

   The WLAN discovery method according to the option set by the user, the user does not activate the trigger timer at the time when the user starts to move in a vehicle equipped with a WLAN access point.
9. In a mobile terminal,

   A memory in which a program for performing a WLAN discovery is stored;

   One or more communication interface modules and

   A processor for executing the program stored in the memory,

   The processor receives a configuration parameter for initiating a WLAN access point discovery through a virtualization layer according to the execution of the program,

   A mobile terminal for setting an operating parameter according to the received setting parameter.
10. The method of claim 9,

    The mobile terminal

    Further includes an LTE protocol layer and a WiFi protocol layer,

    The processor requests mobility information necessary for initiating a WLAN access point discovery to the LTE protocol layer through a virtualization layer,

    Delivers mobility information based on event occurrence to the virtualization layer through the LTE protocol layer,

    If the mobility information satisfies the WLAN discovery start condition,

    Instruct the WLAN discovery to the WiFi protocol layer through the virtualization layer,

    If WLAN discovery is successful,

    A mobile terminal making a request to cancel mobility information transfer to the LET protocol layer through the virtualization layer.
11. The method of claim 9,

    The processor controls the operation of the trigger timer in the virtualization layer,

    A mobile terminal that activates a trigger timer when the mobile terminal starts to move.
12. The method of claim 11,

    The trigger timer is activated when the mobile terminal starts moving, and when the activation of the trigger timer expires, the processor compares the moving speed of the mobile terminal with a scanning mobility reference value through a program.
13. The method of claim 11,

    The trigger timer is not activated at the time when the user starts to move in a vehicle equipped with a WLAN access point according to a selection set by a user.
14. The method of claim 9,

    If the parameter is a scanning mobility value,

    The processor delays the discovery of a WLAN access point when the current mobile terminal's moving speed is greater than the scanning mobility reference value.

    A mobile terminal for initiating a WLAN search when the moving speed of the mobile terminal is less than the scanning mobility reference value.

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