KR20000065869A - Handoff method for mobile communication system - Google Patents

Abstract

PURPOSE: A hand-off method in a mobile communication system is provided to improve a speech quality by preventing that a speech obstacle of a mobile station is occurred or a speech blocking of a mobile station is occurred when performing a hand-off. CONSTITUTION: A mobile station(M) measures a receiving intensity to a base station(B1) and transmits the receiving intensity to the base station(B1)(S'1). The base station(B1) receives the receiving intensity transmitted from the mobile station(M) to judge as to wether the receiving intensity is less than a threshold value and transmits a hand-off start message to a control switch station(S) when the receiving intensity is less than the threshold value(S'2). The switch station(S) receives the hand-off start message and transmits a receiving intensity measuring indication message to the base station(B1) and adjacent base stations(B2-B7)(S'3). The base station(B1) and adjacent base stations(B2-B7) receive the receiving intensity measuring indication message to measure a receiving intensity with the mobile station(M) and transmit a receiving intensity measuring result message to the switch station(S). The switch station(S) indicates a speech channel opening with the mobile station(M) to the greatly excellent base station(B2) and indicates a speech channel closing with the mobile station(M) to the base station(B1)(S'5).

Description

Handoff method for mobile communication system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication system, and more particularly, to a handoff method in a mobile communication system that enables a smooth handoff without causing a call interruption or disconnection in a mobile communication system.

In a mobile communication system, a method of dividing a service area into sectors and managing each sector in one base station is generally adopted. Therefore, when a mobile station moves from one sector to another, the distance between the mobile station and the previous base station is far from the mobile station and the base station, so that the call is disconnected.

In order to solve this problem, a handoff, which is a technology for switching a call path between a mobile station and a base station so that a call is continuously maintained even when a mobile station moves a sector in a service area, is used in a mobile communication system.

Hereinafter, a handoff method in a mobile communication system that has been conventionally applied will be described with reference to FIGS. 1 and 2.

In the conventional mobile communication system, the handoff method includes a step (S1) in which the mobile station M measures the signal strength of the base station B2, and whether the signal strength of the base station B2 is larger than the threshold value by the mobile station M. If the signal strength of the base station B2 becomes larger than the threshold, it is determined that the signal strength measurement result message is transmitted to the base station B1 until the handoff instruction message to use both the base stations B1 and B2 is received. In step S2, the base station B2 transmits a call signal to the mobile station M. After receiving the signal strength measurement result message at the base stations B1 and B2, the mobile station M receives a signal. Transmitting a handoff instruction message to use both of the base stations B1 and B2 (S4), and transmitting a handoff completion message to the base stations B1 and B2 from the mobile station M receiving the handoff instruction message. In step S5, the handoff completion message is received. Transmitting a handoff indication message to use only the base station B2 for the mobile station M at the stations B1 and B2 (S6), and the base stations B1 and B2 at the mobile station M receiving the handoff indication message; (S7) and the base stations (B1 and B2) receive the handoff completion message while the base station (B1) stops the transmission and reception of the call channel to complete the handoff. It consists of S8.

However, according to the handoff method in the conventional mobile communication system described above, the mobile station M until the mobile station M receives a handoff indication message to use both the base stations B1 and B2 from the base stations B1 and B2. ) Has to repeatedly transmit the signal strength measurement result message to the base station (B1), so that the call quality of the mobile station (M) or the call disconnection of the mobile station (M) occurs during the handoff process. There was a problem falling.

SUMMARY OF THE INVENTION An object of the present invention is to provide a handoff method in a mobile communication system according to the present invention, thereby preventing handset failure or disconnection of a mobile station in the handoff process so that handoff can be performed smoothly. The purpose of the present invention is to improve call quality in mobile communication.

1 is a schematic configuration diagram of a mobile communication system;

2 is a flowchart showing a handoff method in a conventional mobile communication system;

3 is a flowchart illustrating a handoff method in a mobile communication system according to a preferred embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

M: Mobile station B1: Base station in a call

B2-B7: Base station adjacent to B1 S: Switching station

In order to achieve the object of the present invention described above, the present invention comprises the steps of: sending a handoff indication message to the two base stations involved to use both base stations, a handoff completion message from the mobile station to the two base stations; Transmitting, from the two base stations, a handoff instruction message to use only the base station having the best reception sensitivity, transmitting a handoff completion message from the mobile stations to the two base stations, and A handoff method in a mobile communication system, comprising: a base station suspending transmission and reception of a communication channel to complete a handoff, wherein prior to performing the steps, a reception sensitivity is received from the mobile station to a base station in a call. Transmitting, at the base station, whether the reception sensitivity is less than the threshold Transmitting a handoff start message to a competent switching center, transmitting a reception sensitivity measurement instruction message to the base stations at the competent switching center, and measuring the reception sensitivity with the mobile station at the base stations. Transmitting a reception sensitivity measurement result message to a competent switching center, and instructing a communication channel to open a communication channel to a base station having the best reception sensitivity, while instructing a closing of a communication channel to a base station in a call; It provides a handoff method in a mobile communication system, characterized in that performed.

Hereinafter, a preferred embodiment of a handoff method in a mobile communication system according to the present invention will be described with reference to FIGS. 1 and 3.

First, the configuration of the above embodiment will be described.

Initially, step S'1 is performed in which mobile station M measures reception sensitivity for base station B1 in a call state and transmits reception sensitivity to base station B1.

Next, the base station B1 receives the reception sensitivity transmitted from the mobile station M, determines whether the reception sensitivity has fallen below the threshold, and judges that the reception sensitivity has fallen below the threshold. A step S'2 of transmitting a handoff start message to the switching center S is performed.

Next, in the jurisdiction switching center S receiving the handoff start message, transmitting a reception sensitivity measurement instruction message to the base station B1 and the base stations B2 to B7 adjacent to each other ( S'3) is performed.

Subsequently, the reception sensitivity measurement result of the receiving switching station S was measured by measuring the reception sensitivity of the base station B1 and the adjacent base stations B2 to B7 that received the reception sensitivity measurement instruction message with the mobile station M. A step S'4 of transmitting a message is performed.

Subsequently, the base station B2 having the best reception sensitivity is instructed by the jurisdiction switching station S that has received the reception sensitivity measurement result message to open the talk channel with the mobile station M, while the base station B1 that has been in a call state is already in the call. In step S'5, instructing the closing of the communication channel with the mobile station M is performed.

Next, the base stations B1 and B2 which have received the call channel opening and call channel closure instructions transmit a handoff indication message to the mobile station M to use both the base stations B1 and B2 (S'6). Is performed.

Next, the mobile station M receiving the handoff indication message transmits a handoff completion message to the base stations B1 and B2 (S'7).

Subsequently, in step S'8, a base station B1 and B2 receiving the handoff completion message transmits a handoff instruction message to use only the base station B2 for the mobile station M.

Subsequently, in step S'9, a mobile station M receiving the handoff instruction message transmits a handoff completion message to the base stations B1 and B2.

Next, the base station B1 and B2 receive the handoff completion message, while the base station B1 stops the transmission and reception of the call channel and completes the handoff (S'10).

On the other hand, as described above, after the step of transmitting the reception sensitivity from the mobile station to the base station in a call state is performed, the base station B1 receives the reception sensitivity transmitted from the mobile station M and the reception sensitivity is taken over. If it is determined that the drop is less than the threshold value, and it is determined that the reception sensitivity is not lower than the threshold value, it can be configured to feed back to the first step.

Then, as described above, the step of measuring the reception sensitivity with the mobile station in the base stations and transmitting the reception sensitivity measurement result message to the competent switching station is performed, and then receiving the reception sensitivity measurement result message ( In S), if it is determined that the base station having the best reception sensitivity is the same base station as the base station B1 in the call state, it may be configured to be fed back to the first step (not shown in the flowchart of FIG. 3). ).

Next, the operation of the embodiment will be described.

In step S'1, the reception sensitivity of the base station B1 in the call state at the mobile station M is measured and transmitted to the base station B1. In step S'2, when the reception sensitivity is judged at the base station B1 to be lower than the threshold, it is determined that the reception sensitivity is lowered to the threshold or lower. Off-start message is sent. In step S'3, a reception sensitivity measurement instruction message is transmitted from the switching center S to the base station B1 in a call state and the base stations B2 to B7 adjacent thereto. In step S'4, the reception sensitivity of the mobile station M is measured at the base station B1 and the neighbor base stations B2 to B7, and a reception sensitivity measurement result message is transmitted to the competent switching center S. In the step S'5, the opening of the call channel with the mobile station M is instructed to the base station B2 having the best reception sensitivity from the jurisdiction switching station S, and to the base station B1 that was in the call state. Is closed, the communication channel with the mobile station M is instructed. In step S'6, a handoff instruction message is transmitted from the base stations B1 and B2 to use both the base stations B1 and B2 for the mobile station M. In step S'7, a handoff completion message is transmitted from the mobile station M to the base stations B1 and B2. In step S'8, a handoff indication message is transmitted from the base stations B1 and B2 to use only the base station B2 for the mobile station M. In step S'9, a handoff completion message is transmitted from the mobile station M to the base stations B1 and B2. In step S'10, transmission and reception of a call channel are stopped at the base station B1, and the handoff is completed.

On the other hand, according to another embodiment, after the step S'1 is performed, it is determined whether the reception sensitivity transmitted from the mobile station M is received at the base station B1 so that the reception sensitivity falls below the threshold. If it is determined that the reception sensitivity is not lowered below the threshold value, the feedback may be fed back to the first step.

Further, according to another embodiment, the base station in which the base station having the best reception sensitivity is already in a call state at the competent switching center S where the reception sensitivity measurement result message is received after step S'4 is performed. If it is determined that it is the same base station as (B1) may be fed back to the first step.

According to the handoff method in the mobile communication system according to the present invention, the call quality of the mobile communication is improved in the mobile communication by preventing the occurrence of a call interruption or disconnection of the mobile station during the handoff process. The effect is improved.

On the other hand, if the reception sensitivity is configured to be fed back to the first step after the step of transmitting the reception sensitivity from the mobile station to the base station that is in a call state is determined that the reception sensitivity is not lowered below the threshold, the reception sensitivity The effect is to prevent the handoff from occurring under normal conditions above the threshold.

Then, the base station measures the reception sensitivity with the mobile station and transmits the reception sensitivity measurement result message to the competent switching center, and then the base station having the best reception sensitivity in the competent switching station is the same base station as the base station in the call state. When it is determined to be, when it is configured to feed back to the first stage, an effect of preventing an unnecessary handoff is exerted when the mobile station moving to another sector returns to the existing sector again.

Claims (3)

Two related base stations transmitting a handoff indication message to the mobile station to use both base stations, transmitting a handoff completion message from the mobile station to the two base stations, and a base station having the best reception sensitivity from the two base stations to the mobile station; Transmitting a handoff indication message to use only a number; transmitting a handoff completion message from the mobile station to the two base stations; and completing a handoff by stopping transmission and reception of a communication channel by a base station previously in a call state. In the handoff method in a mobile communication system comprising: before performing the steps, Transmitting reception sensitivity from the mobile station to the base station in the call; Transmitting, by the base station, a handoff start message to a competent switching center when it is determined that the reception sensitivity is lowered to a threshold value or less; Transmitting a reception sensitivity measurement instruction message to the base stations by the competent switching center; Measuring reception sensitivity with the mobile station at the base stations and transmitting a reception sensitivity measurement result message to the competent switching center; and And a step of instructing the communication channel to be open to the base station having the best reception sensitivity, while instructing the communication channel to be closed to the base station that was in a call state. . The method as claimed in claim 1, wherein the step of transmitting reception sensitivity from the mobile station to the base station in a call state is performed as described above, and when it is determined that the reception sensitivity is not lowered to a threshold value or less, the first transmission is performed again. Handoff method in a mobile communication system, characterized in that fed back to the step. The method according to claim 1 or 2, wherein the base station measures the reception sensitivity with the mobile station and transmits a reception sensitivity measurement result message to the competent switching station as described above. And if it is determined that the base station having the best sensitivity is the same base station as the base station in the call state, it is fed back to the first step.