KR20060062950A - Apparatus and method of hand-off cell selection in portable internet network - Google Patents

Abstract

The present invention relates to an apparatus and method for handoff cell selection in a portable Internet network.

The access point of the present invention receives the handoff candidate cell information transmitted from the mobile terminal and the signal strength information of each cell to determine whether handoff is possible between cells managed by the mobile terminal, and if so, the mobile terminal performs the handoff. Otherwise, handoff candidate cell information and signal strength information are transmitted to the packet access router. The access point selects a candidate cell satisfying the quality of service by using the received handoff candidate cell information, aligns the cells according to the signal strength of the selected candidate cell, and transmits the sorted cell information to the mobile station.

As described above, according to the present invention, by selecting a cell providing the quality of service being used by the mobile terminal and sorting the selected cells according to signal strength, the mobile terminal can efficiently select a handoff cell.

Handoff, quality of service, signal strength, PAR

Description

Apparatus and method of hand-off cell selection in portable internet network

1 is a block diagram showing the structure of a portable Internet network according to an embodiment of the present invention.

2 is a flowchart illustrating a method of selecting a handoff cell in a portable Internet network according to an exemplary embodiment of the present invention.

The present invention relates to an apparatus and a method for selecting a handoff cell in a portable internet network, and more particularly, to an apparatus and a method for selecting a handoff cell in a portable internet network for providing the best stable quality of service during handoff in a portable internet network. It is about.

With the emergence of various multimedia services, the necessity of providing the best quality of service for systems providing Internet access services is increasing. In particular, when providing Internet services in a mobile communication network, the necessity of providing such quality of service becomes more important. .

In a mobile network, a cell is configured around a base station, and cells may have various shapes and overlap each other depending on the size of a service area. Unlike a fixed network, a mobile network supports a handoff function for changing a cell to be connected in consideration of a user's movement. The mobile network should select an optimal cell to be changed in order to prevent a deterioration of service quality provided during handoff.

A method of using signal strength is used as a method of selecting a cell to be moved during handoff. According to the method, the mobile station measures the strength of the signal continuously received from the base station, and if the strength of the signal received from the currently serving base station is less than a predetermined level to measure the strength of the signal received from another adjacent base station, Of these, the strongest base station is selected as the cell to move.

Korean Patent Laid-Open Publication No. 10-2002-0068064 (Method for setting a handoff area of a wireless data terminal; hereinafter referred to as a prior art) uses a handoff method using such signal strength and uses a code division multiple access (CDMA) mobile communication system. In the present invention, a terminal proposes a handoff zone setting method for more accurately predicting a unit cell to be moved when a prediction zone exists.

The prior art solves the problem of unnecessarily wasting resources in all adjacent cells by estimating resources for handoff in consideration of the signal strength of the handoff prediction zone and the base station. However, since the above-described prior art is a method of estimating resources for handoff by considering only the signal strength of a base station, there is a problem in that it is not possible to guarantee whether information on network structure and quality of service are provided.

On the other hand, since the portable Internet system must have a function of supporting the quality of service in the wireless network, it is necessary to select an optimal cell to provide the same quality of service continuously during handoff. Accordingly, there is a need for a handoff cell selection method in a portable Internet system for ensuring a more stable service quality without degrading service quality when handing off a mobile subscriber.

In order to solve the above problems, the present invention provides a handoff cell selection apparatus and method that can select a cell to perform a handoff more effectively while providing a quality of service during handoff of the mobile terminal in the portable Internet network It is for.

An apparatus for selecting a handoff cell in a portable internet network according to an aspect of the present invention for achieving the above object is

Perform wireless communication with a corresponding mobile terminal, and receive handoff candidate cell information received from the mobile terminal, wherein the handoff candidate cell information includes signal strength information received from each cell to the mobile terminal; One or more access points; And

Selecting a candidate cell satisfying the quality of service by using the handoff candidate cell information received from the access point, sorting the selected cell based on the signal strength information included in the handoff candidate cell information, and sorted cell information At least one packet access router for transmitting to the mobile terminal through the access point.

On the other hand, the handoff cell selection method of the portable Internet accessor according to the characteristics of the present invention

Handoff in a mobile Internet network comprising a plurality of cells performing wireless communication with a user's mobile terminal, one or more access points controlling the plurality of cells, and one or more packet access routers managing and controlling the access points As a cell selection method,

(a) Handoff candidate cell information from the mobile station in which an access point performs wireless communication with a cell controlled by the access point; The handoff candidate cell information includes signal strength information received from each cell to the mobile station. Receiving-;

(b) the access point sending the handoff candidate cell information to a packet access router managing it;

(c) the packet access router selecting a candidate cell satisfying the quality of service using the received handoff candidate cell information;

(d) sorting the selected candidate cells based on the signal strength information included in the handoff candidate cell information; And

(e) transmitting the information of the sorted cell to the mobile terminal through the access point to perform the handoff by the mobile terminal.

Hereinafter, 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 accompanying drawings, parts irrelevant to the description of the present invention are omitted for clarity, and like reference numerals designate like parts.

In a portable Internet system, a cell may be configured of an omnicell and a cell having three sectors, one access point (AP) may have several wireless channels, and a packet access router (PAR) Manage several or dozens of APs and control handoffs between them.

In this system structure, handoff between sectors, between APs, and between PARs is possible, and thus, the present invention proposes a handoff method considering a quality of service and a system structure for a successful handoff and an efficient handoff.

1 is a block diagram showing the structure of a portable Internet network according to an embodiment of the present invention.

Referring to FIG. 1, a portable Internet network that provides a portable Internet service to an access terminal 110 may include a plurality of cells 120, 121, and 122, a plurality of APs, and It includes a number of PAR 140.

According to an embodiment of the present invention, the plurality of cells includes a single cell 120 and 121 and a cell 122 having three sectors, respectively, and each AP 130 directly controls a corresponding cell and is configured in a network configuration. Therefore, several frequency bands can be managed. Accordingly, according to an embodiment of the present invention, the AT 110 may perform an intersectoral handoff within one AP 130 or may perform a handoff for changing a currently connected frequency band to another frequency band. . Each PAR 140 manages the corresponding AP 130, controls handoff between the APs 130, and controls handoffs between the PARs 140 in association with other PARs 140.

In short, in the embodiment of the present invention, since the inter-sector handoff, the inter-AP handoff, and the inter-PAR handoff can be provided, the optimal cell can be selected by selecting an appropriate handoff method in consideration of the quality of service. .

Intersectoral handoff is performed within one AP 120, so that control messages including security and transmission of user data packets are not required between subsystems due to cell changes during AT110 handoff. The handoff delay can be minimized.

The handoff between APs 130 is a handoff in which the AP 130 is changed when the cell is changed. Accordingly, a control message including security between the APs 130 is transmitted from the AP 130 of the new cell to the AP 130 of the new cell. Is sent). In addition, user packets that have already been transmitted to the previous AP 130 to be transmitted to the AT 110 should also be transmitted back to the new AP 130.

Meanwhile, the handoff between PAR 140 is a handoff in which the PAR 140 is changed when the cell is changed. Accordingly, a control message including security between the APs 130 is transmitted from the AP 130 of the old cell to the AP of the new cell. The control information is transmitted from the old PAR 140 to the new PAR 140. In addition, user packets that have already been transmitted to the previous AP 130 to be transmitted to the AT 110 should also be transmitted to the new AP 130, and after the handoff is determined, the user packets arriving at the previous PAR 140 are transferred to the new PAR. Must be forwarded to 140.

A handoff cell selection method in a portable Internet network according to an embodiment of the present invention having the above structure is as follows.

2 is a flowchart illustrating a method of selecting a handoff cell in a portable Internet network according to an exemplary embodiment of the present invention.

Referring to FIG. 2, first, the AT 110 measures the strength of a signal received from an AP 130 currently connected (S201), and determines whether the strength of the received signal falls below a predetermined level. (S202).

As a result of the determination in step S202, when the signal strength from the currently connected AP 130 is less than or equal to a predetermined level, the AT 110 obtains permission from the AP 130 and performs scanning on neighboring candidate cells. The strength of the signal received from each candidate cell is measured (S203), and the information on the measured signal strength is transmitted to the AP 130 currently connected (S204).

The AP 130 currently connected determines whether the list of candidate cells transmitted by the AT 110 is a cell managed by itself (S205), and when the cells are all managed by the AP 110, a signal received from the AT 110. Based on the strength information, the AT selects a candidate cell that has transmitted the signal having the greatest strength and performs handoff. In operation S206, the AP 130 notifies the upper PAR 140 of the handoff result (S207) and updates the information in the PAR 140 (S208).

As a result of the determination in step S205, when there is a cell belonging to another AP 130 in the list of candidate cells transmitted by the AT 110, the currently connected AP 130 requests cell selection for handoff. The message is transmitted to the upper PAR 140 (S209).

Upon receiving the cell selection request message for handoff, the PAR 140 selects a cell capable of satisfying the service band currently used by the AT 110 from among candidate cells selected by the AT 110 (S210). Here, the cell capable of satisfying the service band refers to a cell capable of guaranteeing the quality of service used by the AT 110. According to an embodiment of the present invention, the PAR checks using the bandwidth utilization of the cell at the time when the information about the cell below the PAR 140 to which the AT 110 is currently connected is requested, and the PAR currently being accessed. In the case where the cell is not under 140, the mobile station determines using the bandwidth utilization rate of the adjacent PAR 140 that is periodically received.

Then, the PAR 140 to which the AT 110 is currently connected determines whether there is a cell capable of intersectoral handoff among the cells selected in step S210 (S211). Among these cells, the cells are sorted in ascending order based on the information of the signal strength transmitted by the AT 110. (S212)

In addition, the PAR determines whether there is a cell capable of handoff between APs 130 among candidate cells excluding cells capable of inter-sector handoff (S213), and if there is a cell capable of handoff between APs, AT 110. The cells are arranged in order of increasing strength based on the signal strength information of the cell transmitted by S) (S214).

Since the remaining cells except the cells capable of handoff between sectors and the handoff between AP 130 are the handoffable cells between the PAR 140, the PAR 140 is the signal strength of the cell transmitted by the AT 110 among the remaining cells. Based on the information, the cells are sorted in ascending order of size (S215).

The currently connected PAR 140 sorts the handoff cells between sectors, between APs 130, and between PARs 140 in the order of steps S211 through S215 (S216), and AT sorts the list of aligned candidate cells. Transmit to 110 (S217).

Upon receiving the sort list of candidate cells in step S217, the AT 110 selects a cell to actually handoff according to an internal policy.

As described above, according to the embodiment of the present invention, in the handoff of the AT 110, the PAR 140 preferentially selects a cell that can satisfy the quality of service being used by the AT 110, and then By creating a list of candidate cells capable of various types of handoffs using the signal strengths and providing them to the AT 110, the AT 110 can select a handoff cell that can satisfy both the quality of service and the signal strength at the same time. do.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various other modifications and changes are possible.

As described above, the apparatus and method for handoff cell selection in a portable Internet network according to the present invention provides a quality of service used by a mobile terminal in selecting a handoff cell by a PAR for handoff of the mobile terminal. By selecting the cells to be sorted and sorting the cells according to the signal strength and providing them to the mobile terminal, it is possible to select an efficient handoff cell by selecting a good signal strength condition while ensuring the quality of service.

Claims (10)

An apparatus for selecting a handoff cell according to a movement of a mobile terminal in a portable internet network providing a mobile internet service to a user's mobile terminal, Perform wireless communication with a corresponding mobile terminal, and receive handoff candidate cell information received from the mobile terminal, wherein the handoff candidate cell information includes signal strength information received from each cell to the mobile terminal; One or more access points; And Selecting a candidate cell satisfying the quality of service by using the handoff candidate cell information received from the access point, sorting the selected cell based on the signal strength information included in the handoff candidate cell information, and sorted cell information And at least one packet access router for transmitting to the mobile station through the access point. The method of claim 1, When all of the handoff candidate cells received from the mobile station are cells managed by the access point, the access point selects a candidate cell having the largest signal strength of the candidate cell received from the mobile station and performs the handoff. A handoff cell selector for a portable internet accessor. The method of claim 1, And the packet access router classifies the selected cells into inter-sector, inter-access point, and inter-packet access router handoff-capable cells, and sorts the classified cells according to signal strength. The method according to any one of claims 1 to 3, And the packet access router selects a candidate cell satisfying the quality of service among candidate cells belonging to the lower level by using the bandwidth utilization rate of the cell at the time when the mobile terminal receives a handoff request from the mobile station. The method according to any one of claims 1 to 3, The apparatus for selecting a handoff cell in a mobile Internet network for selecting a candidate cell satisfying a quality of service among cells belonging to another packet access router by using the bandwidth utilization information of an adjacent packet access router received at regular intervals. . Handoff in a mobile Internet network comprising a plurality of cells performing wireless communication with a user's mobile terminal, one or more access points controlling the plurality of cells, and one or more packet access routers managing and controlling the access points In the cell selection method, (a) handoff candidate cell information from the mobile station in which an access point performs wireless communication with a cell controlled by the access point; the handoff candidate cell information includes signal strength information received from each cell to the mobile station; Receiving a box; (b) the access point sending the handoff candidate cell information to a packet access router managing it; (c) the packet access router selecting a candidate cell satisfying the quality of service using the received handoff candidate cell information; (d) sorting the selected candidate cells based on the signal strength information included in the handoff candidate cell information; And (e) transmitting the information of the sorted cells to the mobile terminal through the access point, so that the mobile terminal performs handoff. The method of claim 6, Step (b) is Determining, by the access point, whether all candidate handoff cells received from the terminal are cells that can be controlled by the access point; And If all of the received candidate handoff cells are cells managed by the mobile station, selecting the candidate cell having the largest signal strength of the candidate cell received from the mobile station and allowing the mobile station to perform handoff; Method for selecting a handoff cell in a mobile internet network. The method of claim 7, wherein And the access point sending a result of performing the handoff of the mobile terminal to the packet access router, so that the packet access router updates information. The method of claim 6, In step (d), a signal strength of each cell is classified by dividing a candidate cell capable of handoff between sectors, a candidate cell capable of handoff between access points, and a candidate cell capable of handoff between packet access routers among the selected candidate cells. A handoff cell selection method in a portable internet network, characterized in that the sorting is performed according to size. The method of claim 6, Step (d) Classifying candidate cells capable of handoff between sectors within the same access point among the selected candidate cells, and sorting the candidate cells according to signal strength of each cell; Dividing the candidate cells capable of handoff between access points among the remaining cells except for the inter-sector handoff cells among the selected candidate cells and sorting the candidate cells according to signal strength of each cell; And And determining that handoff between packet routers is possible for the remaining cells among the selected candidate cells, and sorting according to signal strength.

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