KR20000061143A - Paging method for hierarchical cell structure in mobile communication system - Google Patents

Abstract

PURPOSE: A paging method in a mobile communication system for supporting a hierarchial cell is provided to select a suitable layer and allocate a channel in a switch by performing a paging according to a macro cell when the switch performs the paging to a base station and performing a response to the paging according to a micro cell unit. CONSTITUTION: A switch transmits a paging message to base stations(T1). Base stations for receiving the message transmit the paging message to a user using a paging channel(T2). The user receives the message and transmits a message for informing a receipt of the paging message to a neighboring micro base station using an access channel used in a micro base station(T3). The micro base station transmits the message to the switch(T4). The switch instructs that a call is set with the user to an optimum base station and simultaneously allocates a channel(T5). The user transmits a response message for informing a receipt of a channel allocation to the optimum base station(T8). The switch informs that a base station selected by the user is any base station and an allocated channel to the micro base station(T6). The base station transmits the allocated channel to the user(T7).

Description

Paging method for hierarchical cell structure in mobile communication system

The present invention relates to a paging method in a mobile communication system supporting a hierarchical cell. In particular, when an incoming call occurs in a mobile communication system supporting a hierarchical cell, paging is a method of determining a location of a called user and setting up a call. The present invention relates to a paging method for improving the efficiency of call management by providing an implementation method and a method for registering location registration information which is information used for the location determination.

In general, when an outgoing signal is generated by a caller in a mobile communication system consisting of only a single cell, a call setup process with a called user by an incoming call included in the outgoing signal is performed through a process as shown in FIG. 1.

When there is a call setup request by the caller 1 with the called party (a), the call is transmitted to the calling party's network 2 to which the caller 1 is subscribed.

The calling party's network 2 sends a call setup request for the call to the called party's home switchboard 3, and the called party's home exchanger 3 receives the call request. It is sent to the registered Home Location Register (HLR) (4) (c).

Subsequently, the subscriber location register 4 requests route information for call setup to the visitor location register (VLR) 5 in which the received current recipient is registered (d), and the destination visitor location register ( 5) after confirming that the called party is registered, collecting information about the route at the called party visited exchange 6 (e, f), and sending the information about the calling route back to the subscriber location register 4; (g).

When the route information collected above and the user information stored in the subscriber location register 4 are sent to the called party home exchange 3 (h), the called party home exchange 3 confirms the routing to the calling party network 2. Send a message (i). Subsequently, the originating network 2 uses this information to establish a call with the called party's visited exchange 6 (j).

The called party visited exchange 6, which has been requested to set up the call, sends a paging message to each base station 7 in the location registration area where the user (here, the called party) is registered for call setup (k).

Each base station 7 in the current location registration area that has received the paging message transmits a paging message for finding the called user (l), and the called user who receives the transmitted message transmits a response to paging (m). . The base station 7 which has received this response message transmits to the called party exchange 6 that it has received the response (n).

Upon receiving the response message, the called party visited exchange 6 searches for a response message from each base station 7 to determine which base station the user is currently in, and sets a call path to the determined base station. When this process is completed, the called party visited exchange 6 transmits a call setup completion message to the calling party network 2, thereby making a call setup between the calling party and the called user (o).

On the other hand, when looking at the registration method of the location registration information that is requested to each location register when paging, each mobile terminal user is the first to provide information about their location until the user turns off the power until the user turns off the power It registers in the visitor location register (VLR) which is the database inside the subscribed exchange and the subscriber location register (HLR) which is the user information processing device.

When the user supplies power, the process of registering his location is as shown in FIG.

When the user 9 supplies the power of the terminal, the terminal automatically sends a location registration message to the exchange to which it is subscribed, and the exchange receives the location round of the user to the visitor location register (VLR) 5. Request (p). The visitor location register 5 which has received the location registration request registers the location information for the user and then transmits the information to the subscriber location register (HLR) 4 to request location registration (q). (4) registers the location of the user according to the request and transmits a location registration confirmation message to the visitor location register (5) (r)

In this case, the information registered in the visitor location register (VLR) 5 is information on the location registration area to which the user currently belongs, and the information registered in the subscriber location register (HLR) 4 refers to an exchange to which the current user belongs, Information about the visitor location register (VLR) 5.

When the visitor location register (VLR) 5 receives the confirmation message, the visitor location register (VLR) 5 sends a confirmation message to the user 9 indicating that the registration was successful (s).

If the user moves out of the current location registration area, the current registered location must be updated. The position update at this time is classified into two types depending on whether the update is performed in one exchange area or an update to another exchange area.

3 shows the location update in one exchange area and the location registration process of two exchange periods. The terminal 10 compares the location registration area information transmitted from each base station with the information recorded in its register and detects that its location has changed when these two information are different (S1).

The terminal 10 that detects the change of location transmits a change of its location through a location update request message (S2), and the exchange / visitor location register 11 receiving the location change is already present. It is determined whether the user registered in the visitor location register (VLR), that is, the changed location is the area in the exchange (S3).

As a result of the determination, if the user is already registered, only the location of the visitor location register (VLR) is updated (4), and the user is notified of the location update by sending a confirmation message (S4). Update position in the exchange area of.

On the other hand, if it is determined that the user is not a previously registered user, that is, the changed location is not the inside area of the exchange, the exchange / visitor location register 11 sends this location update request to the subscriber location register (HLR) 4. Position update (S5). Subsequently, after updating the location, the subscriber location register (HLR) 4 sends a message to delete the user's location information to the previously registered exchange / visitor location register 12, and the visitor location register 12 receives the message. Delete the location information (S6).

Subsequently, the subscriber location register 4 transmits a message indicating that location registration has been registered to the new exchange / visitor location register 11 at the same time as the location information deletion message is transmitted, and the exchange / visitor location register 11 receiving the message receives a new message. After registering the user, all location registration procedures are completed by informing the user that the registration is completed (S7).

The conventional location registration / paging method as described above has no problem in a mobile communication system supporting a tomography cell, but when applied to a mobile communication system in which a layer cell is supported, the following problem occurs.

First, in the location registration method, a method of dividing cells composed of different layers into a location registration area is not provided. Also, in a system composed of microcells, the number of paging signals increases rapidly, so a method of managing them is provided. If not, it will cause inefficiency in location registration.

In view of the conventional problems and requirements as described above, the present invention, when performing the paging to the destination base station in the exchange to be performed in units of macrocells, the response to the paging is performed in units of microcells Thus, the objective is to select an appropriate layer at the exchange and make channel assignments.

In addition, another object of the present invention relates to the location registration used when the paging, location registration occurs frequently as the cell is micronized, location registration is a macro to prevent the load on the access channel and the call channel The purpose is to register only by cell.

1 is a flowchart illustrating a call setup process for setting up a conventional incoming call signal.

2 is a flowchart illustrating a process for registering location information of a conventional mobile terminal.

3 is a flow chart showing a conventional location registration change process.

4 is a flowchart illustrating a call setup process when an incoming call occurs in a mobile communication system supporting a hierarchical cell according to the present invention.

5a to 5d are information element definition tables in each message defined by the present invention.

<Explanation of symbols for the main parts of the drawings>

13: switch 14: macro base station

15 micro base station 16 optimal base station

17: user

In order to achieve the above object, in the paging method in a mobile communication system supporting a layer cell including a micro cell and a macro cell,

When a call setup request with the called party occurs by the calling party, the location information of the called party registered through the called party's exchange is collected, and paging for calling the called party at the exchange is performed in units of macrocells.

A plurality of base stations to which the called party receiving the paging is subscribed performs a paging response in units of microcells.

The exchange receives the response and selects a base station corresponding to the characteristics of the user from among the macro cell base station and the micro cell base station to perform channel allocation.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the principle of the present invention will be described.

Normally, paging may be more efficient as the number of cells belonging to one area is smaller, but the narrower the area, the more the number of signals for location registration is increased. In particular, this problem is more serious in a system using a microcell, where a microcell is a small cell serviced by one base station and a larger service area than the microcell, thereby serving an area including a plurality of microcells. The cell is called a macro cell.

Therefore, all paging and location registration is advantageously performed in macrocell units, and the terminal receiving the paging signal sends a response to inform its own location. This is advantageous.

Accordingly, in the present invention, it is possible to achieve the efficiency of the system by ensuring that each layer is responsible only for functions that are advantageous to them.

The paging method proposed by the present invention by applying the above principle will be described with reference to FIG. 4.

When an incoming call to find a user occurs, the exchange 13 searches its visitor location register to determine which base station to page. The base stations at this time are the macro base stations 14. The exchange 13 sends a paging message to the base stations 14 to be paged (T1), and the base stations 14 receiving the message send a paging message to the user 17 using their paging channels (T2). .

The user receives the message and sends a message indicating that the paging message has been received to the surrounding micro base station 15 by using the access channel used by the micro base station 15 (T3).

The micro base station 15 receiving the message delivers a message to the switch 13 (T4), and the switch 13 selects an appropriate layer according to the characteristics of the current user, and then uses the message received from each base station 15. The optimal base station 16 is selected.

In this case, when the optimal base station 16 is selected, an optimal layer is selected using information such as a speed and a degree of interest, which is a characteristic of a user, and then an optimal base station is selected from the base stations belonging to the selected layer.

The exchange 13 assigns a channel to the selected optimal base station 16 at the same time as a command to set up a call with the user 17 (T5), and the user 17 responds to the response indicating that the channel has been allocated. The message is transmitted to the selected optimal base station 16 (T8).

In addition, the exchange 13 informs each of the micro base stations 15 which received the response, which base station is optimally selected to the user 17, and the assigned channel (T6), and the base station 15 transmits the information to the user 17. (T7).

Through the above process, since the channel is set between the selected optimal base station 16 and the user 17, a call is set using the channel (T9).

In order to support the method as described above, the following information should be included in the message, which will be described with reference to FIG. 5, and the information previously included will not be described and described.

FIG. 5A is a frame illustrating information added to paging information. The paging information includes not only information of a user who is to receive a call but also a base station identification number (Paging_Tx_Cell_ID), which is information of a sending base station.

In the field indicating the direction of information, the information indicates that the information is transmitted from the network to the user (n → u), and the type field indicating that the information is required or selectable. Mandatory information (M) indicates.

In addition, the response message for the paging is to transmit the information of the base station as it is shown in Figure 5b.

In this case, the information flow is the network direction (u → n) in the user and is required.

This information is used to select the appropriate base station within this layer after selecting the appropriate layer at the exchange. If the user is to be assigned to the macro layer, the call should be set up with the base station 14 included in the response message of the user. If it is advantageous to be assigned to the microphone, the call is set up with the base station to which the response message is delivered.

FIG. 5C shows information added to a channel assignment message. The channel assignment message further includes information (Assigned_Cell_ID) on which cell to set up a call, and the information flow is a user direction in the network (n → u). Is required.

Here, the channel assignment message is configured in three different ways, as shown in FIG. 4, as a message transmitted in steps T5, T6, and T7.

In the case of the T5 stage, the same as the existing message, and in the case of the T6 stage, information about the base station to which the channel is actually allocated is additionally included in the existing message, and in the case of the T7 stage, the message received in the T6 stage. This is a message to convey.

When the user receives the message in step T7, the user sends a channel assignment response message T8 shown in FIG. 5D using the channel of the base station specified in this message.

On the other hand, using the paging method as in the present invention and at the same time the registration method of the location information used during paging is performed only in units of macrocells.

As mentioned above, paging and location registration in the system is advantageously performed in macrocell units, and the response to the paging signal is advantageously performed in microcell units.

Using this point, the mobile communication system supporting the hierarchical cell divides the functions for each layer. The entire area is divided into location registration areas by macrocells. Register location only by unit of area.

At this time, since the actual location registration process is the same as the conventional method, description thereof is omitted.

As described in detail above, the present invention allows the base station to perform paging by separating the functions of the microcell and the macrocell from the layer cell by increasing the paging cost and location registration frequency caused by the microcellization. It has the advantage of mobility management with location registration cost, and when an incoming call occurs, it is possible to select and use a layer suitable for the user's characteristics so that an appropriate layer can be selected according to the situation. This has the advantage of reducing the number of overs.

In addition, preferred embodiments of the present invention are disclosed for the purpose of illustration, those skilled in the art will be able to various modifications, changes, additions, etc. within the spirit and scope of the present invention, such modifications and modifications belong to the following claims You will have to look.

Claims (6)

A paging method in a mobile communication system supporting a layer cell including a micro cell and a macro cell, When a call setup request with the called party occurs by the calling party, the location information of the called party registered through the called party's exchange is collected, and paging for calling the called party at the exchange is performed in units of macrocells. A plurality of base stations to which the called party receiving the paging is subscribed performs a paging response in units of microcells. The paging method in the mobile communication system supporting the hierarchical cell, wherein the exchange receives the response and selects a base station corresponding to the characteristics of the user from among the macro cell base station and the micro cell base station. The method of claim 1, The paging method in the mobile communication system supporting the hierarchical cell, characterized in that for registering the location information and update when the movement is registered in units of macrocells. The method of claim 1, Paging method in a mobile communication system supporting a hierarchical cell, characterized in that when the paging is performed in units of macrocells, an identification number of a base station to be transmitted is included in a paging message. The method of claim 1, Paging method in a mobile communication system supporting a layer cell, characterized in that for transmitting the response message for the paging message by the microcell unit including the identification number of the originating microcell base station. The method of claim 1, When the base station is selected according to the paging response message, a layer cell is selected by using a user's characteristics such as speed and facilitating rate information, and then selecting a base station to allocate a channel in the selected layer. Paging method in supported mobile communication systems. The method of claim 1, When the channel assignment message is transmitted after the base station is selected, the channel assignment message is transmitted to the selected base station. And a channel assignment message including selected base station information indicating that a channel for call setup is allocated to the base stations that are not selected.