KR100950768B1 - Determination Method of Handover between Heterogeneous Networks in a Specific Zone - Google Patents

Abstract

The present invention relates to a method for determining heterogeneous handover between heterogeneous networks in a specific area. The present invention relates to a wireless communication environment in which a second area capable of second wireless communication service is located in a first area, which is a first wireless communication service area. When the wireless terminal located in the first area detects a movement from the first cell to the second cell, the area identifier included in the first signal received from the second cell is read to determine a sub area within the second area currently located. Determining region mobility to the currently located subregion based on previously stored subregion information, calculating a handover weight set according to region mobility, and reflecting the calculated handover weight to heterogeneous manganese Determine whether handover. Accordingly, the present invention prevents unnecessary handovers to heterogeneous networks within certain zones.

Handover, heterogeneous network, area, WLAN, identifier

Description

Handover determination method between on mobile network and another mobile network

The present invention relates to heterogeneous handover. In particular, the present invention relates to a method for determining whether to handover to a homogeneous network or a heterogeneous network when a handover occurs during use of a communication service through a first network in an area where different networks exist.

Currently, various types of wireless communication networks (eg, CDMA networks, WCDMA networks, WiMAX, WLAN, etc.) have been developed and built, and thus there is a mixed area where different wireless networks are mixed. In particular, in a mixed area, a building, a factory, or a specific area requiring security, local area networks (WLAN, zigbee network, and Bluetooth network) are installed.

In these specific areas, the use of services through the local area network is recommended when using a wireless terminal capable of accessing the local area network and other wireless networks (eg WCDMA). Keeps the connection open. For example, in a specific building in which a plurality of access points (APs) are installed, a wireless terminal continuously uses a communication service through a wireless LAN.

By the way, although a local area wireless communication network is established in a specific area, it is located in a CDMA network and / or a WCDMA network. Therefore, if a wireless terminal cannot perform its absolute position measurement at the time of handover or the WCDMA communication environment is better than the short range wireless communication due to other factors, there is a problem of handover to the WCDMA communication network unnecessarily.

On the contrary, when a wireless terminal in communication service through a WCDMA network enters a specific region, even though the local wireless communication network is not used, the continuous communication service is available through the WCDMA network. The problem arises.

An object of the present invention is to provide a method for determining a handover between heterogeneous networks in a specific area that prevents unnecessary handover to another network other than the first wireless network during a communication service using the first wireless network.

According to an aspect of the present invention, a second area is located in a first area, which is a first wireless communication service area, and the second area is in a wireless communication environment in which a second wireless communication service is available. A method for determining handover between heterogeneous networks in a domain is provided.

The heterogeneous inter-network handover determination method includes a first step of detecting, by a wireless terminal located in the first region, a movement from a first cell to a second cell; The wireless terminal reads an area identifier included in a first signal received from the second cell, an identifier indicating a sub area to which each cell belongs among a plurality of sub areas divided by the first area, to determine a sub area currently located. A second step of doing; Determining, by the wireless terminal, area mobility to the currently located subregion based on the information of the previously located subregion; A fourth step of the wireless terminal calculating a handover weight set according to the area mobility; And a fifth step of determining, by the wireless terminal, whether to handover between heterogeneous networks by reflecting the calculated handover weight.

In the above, the first signal is a beacon signal or a probe response signal, and the area identifier is recorded in the element body in an element ID field of a newly defined type to inform the sub area.

The plurality of sub-regions includes a boundary region partitioning all boundary regions between the first region and the second region, and an inner region partitioned into the remaining regions except the boundary region of the second region. The boundary area and the inner area are distinguished.

The area mobility gives a low inter-network handover weight when the wireless terminal moves to the inner region, and gives a high inter-network handover weight when the wireless terminal moves to the border region.

Accordingly, in the fourth step, the handover weight is the highest when the area mobility is a movement from the inner area to the boundary area, and the handover weight is set as the middle when the area mobility is moved from the border area to the border area. When the movement to the inner region or the movement from the first region to the boundary region is made, the handover weight is lowest.

In the fifth step, the calculated handover weight is reflected in the inter-network handover operation.

According to an embodiment of the present invention, the present invention provides a method for determining whether a wireless terminal is located in a specific area that recommends the use of a service through a first wireless network, at a boundary between a first wireless network and another wireless network, or a wireless terminal. The handover weight is calculated according to the direction in which is moved, and the handover is performed using the handover weight, thereby preventing unnecessary handovers between heterogeneous networks within a specific area.

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 said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. In addition, the terms “… unit”, “… unit”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. have.

Now, a method for determining heterogeneous handover between heterogeneous networks in a specific area according to an embodiment of the present invention will be described with reference to the accompanying drawings.

First, a network environment to which the present invention is applied will be described with reference to FIG. 1. 1 is a diagram showing a network environment to which the present invention is applied.

As shown in FIG. 1, the network environment to which the present invention is applied is a communication service for a wide area including a local area wireless communication network (N3) having a narrow area (that is, a specific local area) as a communication service area and a local area wireless communication network. At least one mobile communication network N2 serving as a region is established. The short range wireless communication network may be one of WLAN, Bluetooth, ZigBee, etc. The mobile communication network may be one of CDMA, WCDMA, High Speed Downlink Packet Access (HSDPA), and the like.

In the following description, the local area wireless communication network is referred to as WLAN, and the mobile communication network is referred to as WCDMA. The area in which communication service through WCDMA N2 is available is called area 1 (A1), and the area in which communication service through WLAN N3 is available is called area 2 (A2). Of course, area 1 is a large area including area 2.

Hereinafter, the management method difference between the conventional and the present invention for the WLAN constructed in the second area shown in FIG. 1 will be described with reference to FIGS. 2 and 3.

2 is a diagram illustrating a conventional WLAN environment installed in a specific area, and is a WLAN installed in a building or a factory.

As shown in FIG. 2, a WLAN is installed in a public place, a company, or a factory. An AP (Access Point) 10, which is a wireless access point, is densely installed for smooth WLAN communication service anywhere in the room. That is, the AP 10 installed indoors is installed around the door and is also installed in the inner center side.

However, from the perspective of the user's wireless terminal, the user does not know whether the user currently using the WLAN service is at the inner center side or at the door boundary. For this reason, the wireless terminal of a conventional user attempts to connect to a network having high call quality without considering its own location at the time of handover, so that a handover to a heterogeneous network occurs unnecessarily.

Next, a WLAN according to an embodiment of the present invention constructed in the second region shown in FIG. 1 will be described with reference to FIG. 3. 3 is a view showing a wireless LAN environment installed in a specific area according to an embodiment of the present invention.

As shown in FIG. 3, according to an embodiment of the present invention, an WLAN 10 installed in a public place, a company, or a factory is installed in the same manner as in FIG. 2. That is, the AP 10 installed indoors is installed at the door boundary and also at the inner center side.

However, the present invention enables the user to determine where he is currently using the communication service and where he has been in the past.

To this end, the present invention divides region 2 (A2), that is, a specific local region into a plurality of sub-regions. For example, the present invention divides the area 2 (A2) into the inner area A20 and the boundary area A21. The inner area A20 is an area that is separated from the door by a predetermined distance or more, and refers to an area that does not require handover to WCDMA from the handover position according to the present invention. In addition, the boundary area A21 may be at least one or more areas depending on the orientation in which the door is disposed within a predetermined distance from the door. From the standpoint of handover according to the present invention, the boundary area A21 may be an area capable of handover to the WCDMA.

In addition, in order to enable the user's wireless terminal to determine whether its location is located in the internal area A20 or the boundary area A21, the AP located in the corresponding areas A20 and A20 includes an area identifier. Provide a signal.

Accordingly, the wireless terminal determines whether it is located in the internal area A20 or the boundary area A21 through a signal including the area identifier from the AP of the signal having the highest signal quality (eg, signal strength) among the signals received at the current location. You can see if you are located at).

Of course, the wireless terminal stores the area identifier (or previous location information) of the previous area at the time of handover to calculate the area mobility between the newly moved area and the previous area. Here, the area mobility means information indicating whether the wireless terminal is located in the same area, moved to another area, or moved from which area to which area.

On the other hand, when the area 2 (A2) is a place partitioned into a specific area, not a building, the boundary area A21 is defined as all boundary areas between the area 1 (A1) and the area 2 (A2), the inner area (A20) Is defined as the remaining region except for the boundary region A21 in the region 2 (A2).

Hereinafter, an example of a signal for providing a corresponding area identifier to a user's wireless terminal will be described with reference to FIG. 4. 4 is a structural diagram of a signal frame having a location identifier of an AP according to an embodiment of the present invention.

As shown in FIG. 4, a signal including an area identifier among signals transmitted from the AP is a beacon signal or a probe response signal. The frame of this beacon signal or probe response signal includes a MAC header field and a payload frame body field and a frame check sequence (FCS) field as shown in (a).

In this case, the frame body field is variable in length, and has a plurality of element ID fields in addition to default fields such as a time checking pad, a beacon interval field, a capacity field, and a support rate field.

As shown in (b), the element ID field is composed of an element ID and an element body in which a length and content are recorded.

Here, the element ID may represent one of values of 0 to 255, and the type of the element ID field is determined according to the value. Currently, element IDs 1 to 6 and 16 to 31 have a value, that is, a type is used. For example, the SSID (Service Set ID) is an element ID having a type value of 1.

The length indicates information indicating how many bytes the element body is, and the element body records the content defining the type indicated by the element ID. For example, if the element ID indicates an SSID having a type value of 1, the element body records identifier (ID) information used by the service provider to distinguish different radio cells from the WLAN.

Accordingly, the present invention creates a new type of element ID field (hereinafter referred to as a "location element ID field") that makes it possible to identify each of the areas A20 and A21 and adds it to the frame body of the beacon frame or probe response frame. In this case, the position element ID field includes a position element ID having one of 7-15 and 32-255 for which the type is not designated as a type value for identifying each of the regions A20 and A21 in the region 2 (A2), and the boundary region. And a body element in which an area identifier for distinguishing between A21 and the inner area A20 is recorded.

Thus, the user's wireless terminal reads the location element ID field extracted from the beacon frame or probe response frame received from the AP, in particular the area identifier, to determine whether it is currently located in the inner area A20 or the border area A21. Determine if you are located.

Hereinafter, a method for determining heterogeneous handover between heterogeneous networks in a specific zone according to an embodiment of the present invention will be described with reference to FIG. 5. 5 is a flowchart illustrating a method for determining a handover between heterogeneous networks in a specific zone according to an embodiment of the present invention.

If the quality of the signal received from the AP to which the wireless terminal is currently connected due to the user's movement during the WLAN communication service drops below the set value in the area 2 (A2) where the WLAN communication service is recommended, it is determined that the handover situation is performed (S510). When the terminal determines that the handover is in progress, the terminal determines its current subregion (one of the inner region and the boundary region) identified from the region identifier of the location element ID field of the beacon frame of the currently connected AP, and the sub-network identified from the previously stored AP. The mobility, that is, the direction of movement of the wireless terminal is calculated using the region (one of the inner region and the boundary region) (S520).

At this time, the movement direction is the movement direction between regions, whether the movement of the wireless terminal is made within the same region, has moved from the boundary region A21 to the inner region A20, or moves from the inner region A20 to the boundary region A21. Whether it has moved from area 1 (A1) to area 2 (A2).

When the wireless terminal determines the moving direction of the wireless terminal, the handover weight corresponding to the moving direction is calculated (S530), and the handover weight is reflected in the preset handover operation to handover to the homogeneous network or the heterogeneous network. It is determined whether to hand over to (S540).

The handover operation to which the handover weight is applied is an operation for handover between heterogeneous networks. That is, when the handover target is a homogeneous network, the handover weight is not reflected in the handover operation, and when the handover target is a heterogeneous network, the handover weight is applied.

Hereinafter, the weight calculation process will be described in detail with reference to FIG. 6. 6 is a flowchart illustrating a handover weight calculation method according to an embodiment of the present invention.

The wireless terminal which has grasped its currently located area determines whether the currently located area is the boundary area A21 (S561).

In the case where the current location is the boundary area A21 in the determination S561, the wireless terminal determines whether the previously located area is the internal area A20 (S562), and if the area is the internal area A20, the weight W. Is calculated as 1.5 (S563), and if the previously located area is not the internal area A20, it is determined whether the previous area is the boundary area A21 (S564).

In this determination (S564), if the previous area is the boundary area A21, the wireless terminal calculates the weight W to be 1.0 (S565), and if it is not the boundary area A21, the wireless terminal determines that the area has been entered from the area 1 (A1). W) is calculated as 0.5 (S566).

On the other hand, if it is determined in step S561 that the current area is not the boundary area A21, the wireless terminal determines that it is located in the inner area A20 and calculates a weight W of 0.5 (S566).

As a result, the weight is high since the wireless terminal is likely to move from the area 2 (A2) to the area 1 (A1) when the wireless terminal moves from the inner area A20 to the border area A21, and thus the border area A21. Since the probability that the wireless terminal moves to the area 1 (A1) is slightly lower when the boundary area A21 is moved to the area A21, it is small, and when the mobile terminal enters the area 1 (A1) or moves only in the inner area A20, Is very small since it is very unlikely to move to area 1 (A1).

As a result, the smaller the weight, the lower the likelihood of handover to the heterogeneous network, and the higher the weight, the higher the likelihood of handover to the heterogeneous network.

For example, if it is determined that handover from the WLAN to the WCDMA is possible at the current location without reflecting the handover weight, the handover to the WLAN is preferably performed when the value of the handover weight is low. If the value of the handover weight is large, the handover to WCDMA is actively performed.

The embodiments of the present invention described above are not only implemented by the apparatus and method but may be implemented through a program for realizing the function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded, The embodiments can be easily implemented by those skilled in the art from the description of the embodiments described above.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1 is a diagram showing a network environment to which the present invention is applied.

Figure 2 is an exemplary view showing a wireless LAN environment installed in a specific region in the prior art.

3 is a view showing a wireless LAN environment installed in a specific area according to an embodiment of the present invention.

4 is a structural diagram of a signal frame having a location identifier of an AP according to an embodiment of the present invention.

5 is a flowchart illustrating a method for determining a handover between heterogeneous networks in a specific zone according to an embodiment of the present invention.

6 is a flowchart illustrating a handover weight calculation method according to an embodiment of the present invention.

Claims (8)

In a wireless communication environment in which a second area is located in a first area, which is a first wireless communication service area, and the second area is capable of a second wireless communication service, the method for determining a handover between heterogeneous networks in the first area, A first step of detecting, by a wireless terminal located within the first area, a movement from a first cell to a second cell; The wireless terminal reads an area identifier included in a first signal received from the second cell, an identifier indicating a sub area to which each cell belongs among a plurality of sub areas divided by the first area, to determine a sub area currently located. A second step of doing; Determining, by the wireless terminal, area mobility to the currently located subregion based on the information of the previously located subregion; A fourth step of the wireless terminal calculating a handover weight set according to the area mobility; And And a fifth step of determining, by the wireless terminal, whether to handover between heterogeneous networks by reflecting the calculated handover weight. A method for determining inter-network handover within a specific area. The method of claim 1, And said first signal is a beacon signal or probe response signal. The method of claim 2, And the area identifier is a heterogeneous network handover decision method within a specific area recorded in an element body in an element ID field that informs the sub-region among a plurality of element ID fields forming the first signal. The method according to claim 2 or 3, The sub area is, The method for determining heterogeneous inter-network handover in a specific area including a boundary area that is all boundary areas between the first area and the second area, and an inner area that is the remaining area except the boundary area of the second area. The method of claim 4, wherein And the area identifier is an identifier for distinguishing the boundary area from the internal area. The method of claim 4, wherein The fourth step, Heterogeneous manganese in a specific area that gives a low handover weight when the region mobility moves to the inner region and a high handover weight when the wireless terminal moves to the border region. How to determine handover. The method of claim 6, The fourth step, If the area mobility is a movement from the inner area to the border area, the handover weight is the highest; if the area mobility is a move from the border area to the border area, the handover weight is set to the middle; The method for determining the heterogeneous inter-network handover within a specific zone, wherein the handover weight is lowest when the movement from the first area to the boundary area. The method of claim 7, wherein In the fifth step, the calculated handover weight is reflected in the handover operation to the heterogeneous network.

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