KR100695257B1 - Method and System for Providing Forced Access Handoff for Securing Access Channel Capacity - Google Patents

Abstract

The present invention relates to a mandatory access handoff method and system for securing access channel capacity in a mobile communication system.

The present invention provides the strongest signal strength among a second wireless base station and a third wireless base station, which are adjacent cells, at a specific point in time, even when the mobile communication terminal fails to perform handoff when an attempt to access the first wireless base station is an active cell. A mandatory access handoff system forcibly handing off to a neighboring cell having a neighboring cell (hereinafter referred to as a 'maximum signal neighboring cell'), wherein the first handheld base station, which is an active cell, performs a forced handoff when the access attempt fails. Receives signal strengths of pilot channels from two wireless base stations and a third wireless base station and measures the signal strength, and includes a pilot strength measurement message (PSMM) including signal strength (hereinafter referred to as a PSMM). PSMM transmitted from a mobile communication terminal; A base station transmitter for transmitting a call and maintaining a wireless communication path, and a base station controller for performing a forced access handoff to a maximum signal neighbor cell by comparing signal strengths of neighbor cells at a specific time based on the PSMM signal transmitted from the base station transmitter. It provides a compulsory access handoff system comprising.

According to the present invention, it is possible to prevent an increase in the traffic of the active cell and a decrease in call performance, which may cause continuous access failure of the mobile communication terminal, and to improve the call quality by improving the access success rate of the mobile communication terminal. have.

Access handoff, mobile communication system, handoff

Description

Method and System for Providing Forced Access Handoff for Securing Access Channel Capacity

1 is a flowchart illustrating an access handoff process in a general mobile communication system;

2 is a diagram showing an access method of a mobile communication terminal defined in a CDMA standard document;

3 is a view showing the concept of forcibly handing off a mobile communication terminal to an adjacent cell having a strong signal strength according to an embodiment of the present invention;

4 is a block diagram schematically illustrating a configuration of a mobile communication system for performing a forced access handoff according to an embodiment of the present invention;

5 is a flowchart illustrating a mandatory access handoff process of a mobile communication system according to an exemplary embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

210: Mth Child Access Attempt 220: M + 1th Child Access Attempt

230: Nth lower access attempt 310: Mobile communication terminal

320: first wireless base station 330: second wireless base station

340: third wireless base station 324, 334, 344: base station controller

350: mobile switching center 352: home location register

354: Visitor Locator

The present invention relates to a mandatory access handoff method and system for securing access channel capacity in a mobile communication system. More specifically, in a mobile communication system, when a mobile communication terminal fails to access a specific number of times in an active cell, the mobile terminal continuously sends an access message to the active cell and does not perform a handoff unlike the conventional method of performing access in the active cell again. The present invention relates to a forced access handoff method and system for securing access channel capacity by forcibly handing off a neighboring cell having the strongest signal strength among neighboring cells at a specific time point.

In general, a mobile communication system is a system that operates so that a mobile communication terminal can receive a communication service while moving, and provides a service of the wireless base station while the mobile communication terminal is included in a coverage of one wireless base station. When the mobile communication terminal is moved to a service area of another neighboring wireless base station, a handoff is performed to operate the mobile communication terminal without disconnection. Handoff means that when a mobile communication terminal moves to another cell during a call, a new call channel is allocated from the mobile base station. In the conventional handoff, when a mobile terminal is in a traffic state, a pseudo-noise signal having a strength stronger than that of a currently connected signal is generated when the wireless base station searches for pseudo noise (PN) of the mobile terminal. If found, it attempts a handoff. On the other hand, an access handoff means that the mobile terminal performs a handoff while the traffic is not in a traffic state, and when an access handoff condition occurs, the wireless base station other than the wireless base station where the mobile terminal currently manages the active cell. It provides handoff information of the mobile communication terminal and receives channel information from the wireless base station provided with the information, and performs handoff in an access state. In detail, when the mobile communication terminal transmits an outgoing signal and an incoming signal during handoff and moves the boundary before the call is communicated, the wireless base station analyzes the signal strength among the outgoing messages of the wireless base station received from the mobile communication terminal and responds to the response message (BS). -ACK message or a channel assign message (Channel Assign Message) is transmitted to the mobile communication terminal to increase the call traffic rate, this is called an access handoff.

1 is a flowchart illustrating an access handoff process in a general mobile communication system.

)를 갖는 셀을 분리하지만(S130), 단계 S120에서 인접 셀의 신호 세기 측정이 완료되지 않은 경우 단계 S110으로 돌아가 액세스 절차를 재수행한다. Referring to FIG. 1, the mobile communication terminal continuously measures signal strengths of adjacent cells by measuring signal strengths of pilot channels (S110). Subsequently, in step S120, it is determined whether the signal strength measurement of the adjacent cell is completed. If it is determined in step S120 that the signal strength measurement of the adjacent cell is completed, the strongest signal strength among the adjacent cells (

In step S130, if the signal strength measurement of the adjacent cell is not completed in step S120, the process returns to step S110 to repeat the access procedure.

)에 따라 바이어스 레벨값(

)를 측정한다(S140). 가장 강한 신호 세기를 갖는 인접 셀(이하 '최대 신호 인접 셀'이라 칭함)의 신호 세기가 액티브 셀의 신호 세기보다 바이어스 레벨 값 이상 큰지 판단한다(S150).The signal strength of the active cell is then

Depending on the bias level

) Is measured (S140). In operation S150, it is determined whether the signal strength of the neighboring cell having the strongest signal strength (hereinafter, referred to as 'maximum signal neighboring cell') is greater than or equal to the signal strength of the active cell.

If the signal strength of the active cell is smaller than the signal strength of the maximum signal neighbor cell by more than a predetermined level, the access handoff is performed to the maximum signal neighbor cell (that is, the base station of the maximum signal neighbor cell) (S160), and the signal strength of the active cell is increased. If the signal strength of the maximum signal neighbor cell is not smaller than a predetermined level or more, the process returns to step S110 to repeat the access procedure.

2 is a diagram illustrating an access method of a mobile communication terminal defined in a CDMA standard document.

Referring to FIG. 2, an access attempt represents an overall access process in which a mobile communication terminal sends an access message to a wireless base station and receives a response message, and one access attempt includes multiple (N) lower access attempts. The lower access attempt again includes a plurality of K access probe sequences, and the access probe sequence includes a plurality of access probes, which are basic units for transmitting an access message.

1 and 2, in a conventional access handoff, the signal strength of the neighboring cell is measured in each of a total of N lower access attempts during one access attempt, and the signal strength of the maximum signal neighboring cell is determined by the active cell. If the signal strength is greater than a certain level (bias level value), the access message is transmitted by transmitting the access message to the corresponding maximum signal neighbor cell. It will continue to send active messages to the active cell during the access attempt. In addition, if the access is not successful during one access attempt (i.e., N lower access attempts), the next access attempt is also performed on the current active cell.

On the other hand, the access procedure of the mobile communication terminal may fail due to various factors. The causes of the failure include, besides the weakening of the signal strength of the cell base station, a geographical problem, an increase in traffic load, a problem of the mobile communication terminal itself, and a wireless base station. Or problems of the exchange itself.

However, using the access handoff according to the prior art considering only the signal strength of the wireless base station as described above, even if the access fails for reasons other than the weakening of the signal strength of the base station, the current active continues without an adjacent cell having sufficient signal strength. There is a problem that an attempt is made to access a cell. That is, by continuously transmitting an access message to the base station of the active cell without a normal access handoff, not only increases the traffic load of the active cell but also decreases the probability of success of access, resulting in a decrease in call performance. There is this.

In order to solve the above-mentioned problem, the present invention relates to a conventional method in which a mobile communication terminal continuously sends an access message to an active cell to re-access the active cell when a specific number of access attempts have failed in the active cell in the mobile communication system. It is an object of the present invention to provide a forced access handoff method and system for securing access channel capacity by forcibly performing a handoff to a neighboring cell having the strongest signal strength among neighboring cells at a specific time, even if the situation is not to be handed off. .

Accordingly, according to the first object of the present invention, in a mobile communication system, when a mobile communication terminal fails to access a certain number of access attempts in an active cell, even when the mobile station does not need to handoff the strongest signal strength among neighboring cells at a specific time point, A mandatory access handoff system forcibly handing off to a neighboring cell having a neighboring cell (hereinafter referred to as a 'maximum signal neighboring cell'), wherein the first handheld base station, which is an active cell, performs a forced handoff when the access attempt fails. A mobile communication terminal receiving signal strength from a second wireless base station and a third wireless base station and transmitting a pilot strength measurement message (PSMM) signal including the signal strength; A base station transmitter for transmitting the transmitted PSMM signal to a base station controller; Based on the PSMM signal a terminal has sent out comparing the signal strength of the neighboring cells at a given point in time to provide a forced handoff access system comprising a base station controller for performing a forced access handoff cells adjacent maximum signal.

)를 갖는 셀인 최대 신호 인접 셀을 분리하는 단계; (d) 이동통신 단말기가 액티브 셀에서 액세스 시도 중에 M+1 번째 하위 액세스 시도인지 여부를 판단하는 단계; (e) 이동통신 단말기가 단계 (d)에서 판단 결과 액티브 셀에서 액세스 시도가 M+1 번째 하위 액세스 시도이고, M 번째 하위 액세스 시도까지 정상적인 액세스 핸드오프가 이루어졌는지 판단하는 단계; 및 (f) 단계 (e)에 있어서, M 번째 하위 액세스 시도까지 정상적인 액세스 핸드오프가 이루어지지 않을 경우 M+1 번째 하위 액세스 시도 시점에서 최대 신호 인접 셀로 강제적으로 핸드오프 하는 단계를 포함하는 것을 특징으로 하는 강제적 액세스 핸드오프 방법을 제공한다.According to a second object of the present invention, in a mobile communication system, if a mobile communication terminal fails to handoff a specific number of attempts to access an active cell, the neighbor having the strongest signal strength among neighboring cells at a specific point in time is not in a situation of handoff. A forced access handoff method for forcibly handing off a cell, the method comprising: (a) measuring, by a mobile terminal, signal strength of an adjacent cell by continuously measuring signal strength of pilot channels; (b) determining whether the measurement of the adjacent cell signal strength of step (a) is completed; (c) the mobile terminal has the strongest signal strength among the adjacent cells (

Separating the largest signal neighbor cell that is a cell with &lt; RTI ID = 0.0 &gt; (d) determining whether the mobile communication terminal is the M + 1 th lower access attempt during an access attempt by the active cell; (e) the mobile terminal determining whether the access attempt is an M + 1 th lower access attempt in the active cell and a normal access handoff has been made until the M th lower access attempt as a result of the determination in step (d); And (f) step (e), forcibly handing off to the maximum signal neighbor cell at the time of M + 1 th lower access attempt if normal access handoff is not made until the M th lower access attempt. A mandatory access handoff method is provided.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are designated as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

3 is a diagram illustrating a concept in which a mobile communication terminal forcibly handoffs to an adjacent cell having a strong signal strength according to an embodiment of the present invention.

Referring to FIG. 3, it is assumed that the first wireless base station 320 is an active cell, the second wireless base station 330 and the third wireless base station 340 are adjacent cells, and the second wireless base station 330 is a third wireless base station. Assume that the adjacent cell has a stronger signal strength than 340. When the mobile communication terminal 310 fails to perform a specific number of access attempts within the first wireless base station 320, which is an active cell, the mobile communication terminal 310 performs a forced access handoff at a specific time point even though the mobile communication terminal 310 does not need to perform handoff. Handoff to the second wireless base station 330 having a stronger signal strength than). Although the preferred embodiment of the present invention is limited to three wireless base stations, it may include four or more wireless base stations.

According to a preferred embodiment of the present invention, the mandatory handoff method is limited to the handoff between the mobile communication terminal 310 and the wireless base station, but the wireless base station and the wireless base station, the wireless base station and the mobile communication switching station, the mobile communication switching station and the mobile communication switching station It is also applied to the handoff of the liver.

4 is a block diagram schematically illustrating a configuration of a mobile communication system for performing a forced access handoff according to a preferred embodiment of the present invention.

The mobile communication system 300 according to the present invention includes a mobile communication terminal 310, a first wireless base station 320, a second wireless base station 330, a third wireless base station 340, a mobile communication switching center 350, and a home. A home location register (HLR) 352, a visitor location register (VLR) 354, and the like.

The mobile communication terminal receives the signal strength from the second wireless base station and the third wireless base station (330, 340) to perform a forced handoff when the access attempt in the first wireless base station 320 that is the active cell 310, This signal is transmitted as a pilot strength measurement message (PSMM) signal including a signal strength.

The first, second, and third wireless base stations 320, 330, and 340 may include a base station transmission system (BTS) 322, 332, and 342, and a base station controller (BSC) 324, 334. 344).

Here, the base station transmitters 322, 332, and 342 are arranged in cell units, respectively, and transmit the PSMM signal transmitted from the mobile communication terminal 310 to the base station controllers 324, 334, and 344 in a cell area controlled by the base station controllers 324, 334, and 344. Location registration is performed by identifying the location of the existing mobile communication terminal 310. In addition, the base station transmitters 322, 332, and 342 maintain a wireless communication call or communication path with respect to the mobile communication terminal 310.

Location registration is a processing procedure for informing the mobile communication switching center 350 of the location, status, identifier, slot period, and other characteristics of the mobile communication terminal 310 through the corresponding base station transmitters 322, 332, 342. 322, 332, and 342 are procedures for effectively calling the mobile communication terminal 310 when a call is to be set to the mobile communication terminal 310. The location registration of the mobile communication terminal 310 is performed when the mobile communication terminal 310 is turned on or off, when the mobile communication terminal 310 moves between mobile communication switching stations 350, and the mobile communication terminal ( It is implemented when the parameter of 310 is changed.

The base station controllers 324, 334, and 344 compare the signal strengths of the second wireless base station and the third wireless base station 330 and 340 at a specific time point based on the PSMM signal transmitted by the mobile communication terminal 310, thereby providing a strong signal strength. Perform a forced access handoff to an adjacent cell with

The mobile communication switching center 350 has a control function for allowing the wireless base stations 320, 330, and 340 to be efficiently operated and an interworking function with an exchange of a public telephone network. When the mobile communication switching station 350 registers the location of the mobile communication terminal 310 through the wireless base stations 320, 330, and 340, the mobile communication terminal 310 is connected to the VLR 354 in the mobile communication switching station 350. After temporarily storing the subscriber information, and requests the location registration of the mobile communication terminal 310 to the HLR (352).

Here, the HLR 352 is a database that stores a service profile related to subscriber information of the mobile communication terminal 310. The HLR 352 is a mobile identification terminal (MIN) of the mobile communication terminal 310 including a subscriber's telephone number. ), Terminal Serial Number (ESN) and service type information. The HLR 352 performs a function of storing subscriber information including information of the wireless base stations 320, 330, 340 and the mobile switching center 350 where the mobile communication terminal 310 is located. The mobile communication switching center 350 is composed of a control unit, a call path unit and a peripheral device, and also has a charging data collection function for the mobile communication terminal 310.

5 is a flowchart illustrating a mandatory access handoff process of a mobile communication system according to an exemplary embodiment of the present invention.

)를 갖는 셀(이하 '최대 신호 인접 셀'이라 칭함)을 분리하지만(S530), 인접 셀의 신호 세기 측정이 완료되지 않은 경우에 단계 S510으로 돌아가 액세스 절차를 재수행한다.Referring to FIG. 5, the mobile communication terminal 310 continuously measures signal strengths of pilot channels to measure signal strengths of adjacent cells (S510) and determines whether the measurement is completed (S520). When the measurement of the signal strength of the neighbor cell is completed, the mobile communication terminal 310 has the strongest signal strength among the neighbor cells.

Cell (hereinafter, referred to as 'maximum signal neighbor cell') is separated (S530), but when the signal strength measurement of the neighbor cell is not completed, the process returns to step S510 to perform the access procedure again.

After step S530, the mobile communication terminal 310 determines whether to access in the M + 1 th lower access attempt 220 (S540).

If the mobile communication terminal 310 fails to access the M + 1 th lower access attempt 220 in step S540, it is determined whether access handoff is performed in the lower access attempt 210 up to the M th time (S550).

In step S550, if the mobile terminal 310 does not have a normal conventional access handoff until the M th lower access attempt 210, and the access is not successful, the mobile terminal 310 forces the maximum signal neighbor cell when the M + 1 th lower access attempt is started. After performing the handoff, the access procedure is performed again (S560).

In case of mandatory access handoff, the signal strength of the target wireless base station should be greater than or equal to the signal strength for normal call processing. After forced handoff, normal handoff is not performed until the access attempt is completed. The specific value of M can be arbitrarily set by the administrator as necessary, and setting M to a small value can result in forced handoffs faster.

)에 따라 바이어스 레벨값(

)를 측정하고(S542),When the mobile communication terminal 310 performs the M + 1 th lower access attempt 220 in step S540, if the access handoff is made until the M th lower access attempt 210, the cell does not perform a forced handoff. Perform a normal handoff based on the signal strength of. That is, the signal strength of the active cell (

Depending on the bias level

) Is measured (S542),

In operation S544, it is determined whether the signal strength of the maximum signal neighbor cell is larger than the signal strength of the active cell.

If the signal strength of the maximum signal neighbor cell is greater than the signal strength of the active cell by a predetermined level or more, the access handoff is performed to the maximum signal neighbor cell (that is, the base station of the maximum signal neighbor cell) (S546), otherwise, to step S510. Go back and perform the access procedure again.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

As described above, according to the present invention, it is possible to prevent an increase in the traffic of the active cell and a decrease in the call performance, which may cause continuous access failure of the mobile communication terminal, and to improve the access success rate of the mobile communication terminal. This can lead to an improvement in quality.

Claims (10)

In a mobile communication system, when an access attempt is failed in a first wireless base station in which a mobile communication terminal is an active cell, an adjacent cell having the strongest signal strength among the second and third wireless base stations, which are adjacent cells, at a specific point in time, even when it is not in a situation of handoff. In a mandatory access handoff system for performing mandatory access handoff (hereinafter referred to as 'maximum signal neighbor cell'), When the access attempt fails in the first wireless base station, which is the active cell, the signal strength of pilot channels is received from the second wireless base station and the third wireless base station to measure the signal strength in order to perform the forced access handoff. And a mobile communication terminal transmitting a pilot strength measurement message (PSMM) signal including the signal strength; A base station transmitter for transmitting the PSMM signal transmitted from the mobile communication terminal and maintaining a wireless communication path; And A base station controller performing the forced access handoff to the maximum signal neighbor cell by comparing the signal strengths of the neighbor cells at the specific time point based on the PSMM signal transmitted from the base station transmitter Compulsory access handoff system comprising a. The method of claim 1, The mandatory access handoff system is also applied to a handoff between the first wireless base station, a mobile communication switching center, and the mobile communication switching station. The method of claim 1, After the forced access handoff is performed, the mobile communication terminal does not perform a normal handoff in consideration of a bias level until the end of the access attempt in the corresponding cell. The method of claim 1, And the signal strength of the wireless base station is greater than or equal to the signal strength for normal call processing. In a mobile communication system, when a mobile communication terminal fails to access an active cell, the mobile terminal is a neighboring cell having the strongest signal strength among neighboring cells (hereinafter, referred to as a 'maximum signal neighboring cell') at a specific point of time, even when it is not in a situation of handoff. A forced access handoff method for performing a forced access handoff, (a) measuring signal strength of the adjacent cell by continuously measuring signal strength of pilot channels; (b) determining whether the signal strength measurement of the neighboring cell of step (a) is completed; (c) the strongest signal strength among the adjacent cells (

Separating the maximum signal neighbor cell that is a cell with &lt; RTI ID = 0.0 &gt; (d) determining whether the active cell is an M + 1 th lower access attempt among the access attempts; (e) determining that the access attempt is the M + 1 th lower access attempt in the active cell and that a normal access handoff has been made until the M th lower access attempt in the active cell; And (f) In the step (e), if the normal access handoff is not made until the M th lower access attempt, the forced access handoff is performed to the maximum signal neighbor cell at the time point of the M + 1 th lower access attempt. step Compulsory access handoff method comprising a. The method of claim 5, In the step (d), wherein the access attempt of the mobile communication terminal is made of a total of N lower access attempts, and M is smaller than the N. The method of claim 5, In the step (d), the M value is arbitrarily set by an administrator, and when the M value is made small, the handoff speed is increased. The method of claim 5, In step (d), if it is determined that the normal access handoff is performed until the Mth lower access attempt, performing the normal handoff in consideration of a bias level value without performing the forced access handoff. Characterized in a mandatory access handoff method. The method of claim 5, In the step (d), after the forced access handoff is performed, the normal access handoff method is not performed until the end of the access attempt in the corresponding cell in consideration of a bias level value. . The method of claim 5, In the step (e), the forced access handoff method is performed only when the signal strength of the maximum signal neighbor cell base station is greater than or equal to the signal strength in which normal call processing is possible. .

Images