KR101091036B1 - Method for Hand-Off between Wireless Communication Systems Applying Velocity of Mobile Communication Terminal - Google Patents

Abstract

The present invention relates to a handoff method between heterogeneous wireless communication systems using a moving speed of a mobile communication terminal to perform a handoff in consideration of signal strength and moving speed of a terminal.

The present invention provides a method for handing off a system A mobile communication terminal to a system B by handing the signal strength P_1 and system B at the time when the wireless communication system A starts various procedures for handoff. When the lowest signal strength included in the off candidate set is P_2 and the lowest serviceable signal strength of System A, that is, the signal strength at the time of handoff, is P_3, the signal strength of System A becomes P_1 or less, Determining whether the signal strength is greater than or equal to P_3; Measuring the moving speed of the mobile communication terminal when the signal strength of the system A becomes less than or equal to P_1 or the signal strength of the system B becomes greater than or equal to P_3; Determining whether the measured speed is below the supportable moving speed of the system B; Selecting System B as a handoff candidate if it is below a supportable speed; Determining whether the signal strength of system A is less than or equal to P_3, and whether or not the signal strength of system B is greater than or equal to P_2; Performing a handoff to the system B when the signal strength of the system A is less than or equal to P_3 and the signal strength of the system B is greater than or equal to P_2; It consists of technical features.

Description

Handoff method between heterogeneous wireless communication systems using mobile speed of mobile communication terminal {Method for Hand-Off between Wireless Communication Systems Applying Velocity of Mobile Communication Terminal}

1 is a conceptual diagram illustrating a handoff method of the present invention;

2 is a conceptual diagram illustrating a method for measuring a terminal movement speed according to an embodiment of the present invention;

3 is a conceptual diagram illustrating a method for measuring a terminal movement speed according to another embodiment of the present invention;

4 is a flowchart illustrating a handoff process between heterogeneous wireless communication systems according to an embodiment of the present invention;

5 is a flowchart illustrating a handoff process between heterogeneous wireless communication systems according to another embodiment of the present invention.

The present invention relates to a handoff method between heterogeneous wireless communication systems using a moving speed of a mobile communication terminal. More specifically, in consideration of the difference in the moving speed of a supported terminal for each wireless communication system, not only the signal strength but also the terminal The present invention relates to a handoff method between heterogeneous wireless communication systems using a moving speed of a mobile communication terminal to perform a handoff in consideration of the moving speed of the mobile communication terminal.

In general, in an environment where a plurality of wireless communication systems coexist, the mobile communication terminal selects a system capable of providing a high data transmission speed and a good transmission quality to perform a handoff.

For example, in the case of a dual mode terminal capable of using a CDMA2000 1xEV-DO and a WLAN, the transmission speed of the CDMA2000 1xEV-DO is 2Mbps, whereas the WLAN transmission rate is 54Mbps in the case of IEEE802.11a. Therefore, when the dual mode terminal receives data service through the 1xEV-DO for the first time and enters the WLAN service area, the dual mode terminal attempts to handoff to the WLAN system for high speed data service.

The handoff between the existing multiple wireless communication systems is generally based on the received signal strength (RSSI) of each system. Accordingly, the mobile communication terminal handoffs the received signal when the strength of the received signal rises or falls above a certain level. Will try.

On the other hand, CDMA or GSM-based 2nd and 3rd generation mobile communication systems generally support data transmission for high-speed mobile terminals moving at a speed of 250 km / h. Internet system (or WiBro system) supports low / medium speed of up to 60km / h, and pedestrian speed of about 3km / h in case of wireless LAN system including IEEE802.11b / g / a.                         

In addition, a CDMA mobile phone supports a data transfer rate of up to several Mbps, a portable Internet system may support a maximum data transfer rate of several tens to several tens of Mbps, and a wireless LAN system.

Therefore, in the case of a terminal moving at a pedestrian speed, if several wireless communication systems coexist, it is relatively advantageous to connect to a system having a high data transmission rate by considering only the data transmission rate.

However, in the case of a fast moving terminal, when accessing a system that can only support a pedestrian speed such as a wireless LAN, not only data transmission error is generated but also a medium access opportunity of the terminal connected to the entire wireless LAN is reduced. This reduces system throughput.

That is, in the case of a mobile terminal, if a handoff is determined to a system having a high data transmission rate unconditionally considering only the strength of a received signal as described above, due to the influence of a terminal moving speed supported by each wireless system, the handoff is rather handoff. Has a problem of causing transmission quality degradation.

Particularly, in Korea, a new service called 'mobile Internet' has been proposed as a wireless Internet service that enables high-speed Internet access even during stoppage or low-speed movement using 2.3GHz band. The standard for a mobile environment and the WLAN is a standard for a fixed environment. In the case of a portable Internet, a data rate of about 500 kbps is provided for each subscriber, but a WLAN can guarantee a data rate of several Mbps or more.                         

Therefore, if the existing handoff method is applied as it is when handoff between the portable Internet system and the WLAN system, the terminal selects and connects a WLAN having a strong signal strength even in a mobile environment, which consequently degrades data transmission efficiency. The problem arises.

Accordingly, the present invention is to solve the problems and disadvantages of the degradation of the transmission quality when the handoff method based on the received signal strength between the heterogeneous wireless communication systems having different terminal mobile speed support standards. Rather, by utilizing the movement speed of the terminal additionally to allow handoff between heterogeneous wireless communication systems according to the environment, between heterogeneous wireless communication systems using the movement speed of the mobile communication terminal to receive services in a better connection environment It is an object of the present invention to provide a handoff method.

The object of the present invention is a handoff method between heterogeneous wireless communication systems as a mobile communication terminal receiving a service of system A moves to system B in a region where two wireless communication systems of system A and system B coexist, Signal strength at the time of starting the general procedure for handoff is called P_1, the lowest signal strength including System B in the handoff candidate set is called P_2, and P_3 is the lowest serviceable signal strength of System A, that is, A first step of determining whether the signal strength of the system A is equal to or smaller than P_1 or the signal strength of the system B is equal to or greater than P_3 when the signal strength at the time of handoff is required; A second step of measuring a moving speed of the mobile communication terminal when the signal strength of the system A becomes less than or equal to P_1 or the signal strength of the system B becomes greater than or equal to P_3; A third step of determining whether the measured moving speed of the mobile communication terminal is less than or equal to the supportable moving speed of the system B; A fourth step of selecting the system B as a handoff candidate system when the measured moving speed of the mobile communication terminal is less than or equal to the supportable moving speed of the system B; A fifth step of determining whether the signal strength of the system A is less than or equal to P_3 and at the same time whether the signal strength of the system B is greater than or equal to P_2; A sixth step of performing a handoff to the system B when the signal strength of the system A is less than or equal to P_3 and the signal strength of the system B is greater than or equal to P_2; It is achieved by a handoff method between heterogeneous wireless communication systems using the moving speed of the mobile communication terminal comprising a.

In addition, the above object of the present invention is to hand to any one of the system 1 to system N as the mobile communication terminal receiving the service of the system A moves in the area where the system A and the plurality of wireless communication systems of the system 1 to N coexist. A handoff method between heterogeneous wireless communication systems for performing an off, wherein a signal strength at the time when system A starts various procedures for handoff is called P_1, and any system n of system 1 to system N is handed off. When the lowest signal strength included in the candidate set is called P_2, and P_3 is the lowest serviceable signal strength of the system A, that is, the signal strength at the time of handoff, the signal strength of the system A becomes P_1 or less, or the system B A first step of determining whether or not the signal strength of P_3 is equal to or greater than P_3; A second step of measuring a moving speed of the mobile communication terminal when the signal strength of the system A becomes less than or equal to P_1 or the signal strength of any of the systems n of the system 1 to system P is equal to or greater than P_3; Determining whether the measured moving speed of the mobile communication terminal is less than or equal to the supportable moving speed of system n; A fourth step of selecting the system n as a handoff candidate system when the measured moving speed of the mobile communication terminal is less than or equal to the supportable moving speed of system n; A fifth step of determining whether the signal strength of the system A is equal to or less than P_3 and at the same time whether the signal strength of the system n is equal to or larger than P_2; A sixth step of performing a handoff to the system n when the signal strength of the system A is less than or equal to P_3 and the signal strength of the system n is greater than or equal to P_2; It is achieved by a handoff method between heterogeneous wireless communication systems using the moving speed of the mobile communication terminal.

Details of the above object and technical configuration of the present invention and the resulting effects thereof will be more clearly understood from the following detailed description based on the accompanying drawings.

First, Figure 1 is a conceptual diagram for explaining the handoff method of the present invention.

FIG. 1 illustrates a case where a terminal receives a service of System A and moves in the direction of System B in an area where two wireless communication systems of System A and System B coexist.                     

In the figure, the time point T_1 is a time point when the signal strength of the system A becomes P_1, which is the signal strength at the time to continuously measure the moving speed of the terminal.

The T-2 time point is a time point when P_2, which is the signal strength of System A, is still greater than or equal to the signal strength of System B in which the signal strength gradually increases, and it is a time when System B should be selected as a candidate set for handoff.

The time T_3 is the time when the signal strength of the system A currently being serviced becomes equal to or less than the signal strength of the system B, and the terminal should start handoff to another wireless communication system (system B) or an adjacent cell of the system A.

In the case of a general handoff, when the signal strength of the terminal receiving the service in the system A is lowered below a certain level (P_2) and the signal strength of the system B rises above a certain level (P_2), the system B is Selected as a candidate set for handoff, handoff is performed to system B at the time T_3, when the signal strength of system A is lowered and becomes below a certain level (P_3), and if the signal strength of system B is a certain level ( If not greater than P_2), handoff is attempted to an adjacent cell of the same wireless communication system.

In this case, in the case of a general handoff, only the signal strength is considered, and the signal strength of the system A is lowered to a predetermined level or lower at a time point T_3, and the signal strength of the system B is lowered to a lower level or lower. However, the present invention periodically measures the moving speed of the terminal at the time T_1.

When the time T_2 is reached, the system compares the movement speed of the terminal with the range of the movement speed supported by the system B. If it is determined that the system B can support the movement speed of the current terminal, the system B is selected as a candidate set for handoff. When time T_3 is reached, handoff to system B is performed. In addition, when the system B does not support the movement speed of the current terminal, at the time T_3, the terminal does not perform a handoff to the system B, but performs a handoff to an adjacent cell in the system A itself.

For example, if the signal strength of the IEEE802.11a (WLAN) increases while the mobile communication terminal receives the service of the CDMA2000 1xEV-DO, the terminal measures the moving speed of the terminal, if the terminal is less than 3km / h When moving at the same pedestrian speed as IEEE802.11a supports the pedestrian speed, handoff to IEEE802.11a. If the terminal is moving at a vehicle speed of 120 km / h, even if the signal strength of IEEE802.11a is high, the terminal attempts to handoff from the CDMA2000 1xEV-DO cell that has been serviced to the neighboring cell.

On the other hand, there may be a variety of methods for measuring the movement speed of the terminal, some of the measurement method will be described with reference to FIGS. 2 and 3 as follows. At this time, the present invention is to apply the moving speed to the handoff, and the speed measuring method of various methods can be applied in addition to the following measuring method.

First, FIG. 2 is a conceptual diagram illustrating a method for measuring a terminal movement speed according to an embodiment of the present invention, using a propagation delay or a round trip delay and a path loss (PL). A diagram relating to a method.                     

As shown in FIG. 2, the flow of data between the base station (or AP) and the mobile communication terminal is shown, and a data transmission delay of T_D is generated due to the distance difference between the base station (or AP) and the terminal, and the data processing time Let T_P be the round trip delay T_RT = 2 * T_D.

When the sender sends the time information sent at the time of sending the data, the receiver can know the T_D (transmission delay) or the T_RT (round trip delay) using the sent time and the received time information. If the transmission delay measured in the kth transmission interval is T_D [k], the amount of change in the transmission delay value due to the movement of the terminal becomes ΔT_D = T_D [k + 1] -T_D [k].

If the transmission output at the transmitting side is Pt and the receiving power at the receiving side is Pr, PL = Pt / Pr becomes the transmission loss, and the transmission loss varies with the transmission distance D. In an ideal free space, PL = Pt / Pr ∝ D ² has a relationship.

In the present invention, the virtual distance VD according to the virtual transmission loss is defined.

That is, VD [k] = α {PL [k]} ^β is obtained from PL [k] = Pt / Pr [k] measured in the kth transmission interval based on the transmission loss value of the free space. Here, α and β are constants and are obtained as statistical data on the transmission loss in the wireless channel environment, and in the non line of sight (NLOS) environment such as urban environment, β is affected by the multipath effect. Is known to have a value between 2.5 and 3.5. If the moving distance is obtained from the obtained virtual distance, the moving distance ΔD = VD [k + 1] -VD [k].

Therefore, the moving speed V = ΔD / ΔT_D of the terminal can be obtained from the above obtained ΔT_D and ΔD.

3 is a conceptual diagram illustrating a method of measuring a terminal movement speed according to another embodiment of the present invention, and illustrates a method of measuring speed using GPS location information.

As shown, the moving speed of the terminal can be known from the location information using the GPS. That is, if the terminal position through the k-th position tracking through the position information is called P [k] and the position tracking time is T [k], the terminal moving speed V = {P [k + 1] -P [k]}. / {T [k + 1] -T [k]}.

Meanwhile, a handoff process between heterogeneous wireless communication systems in consideration of the moving speed of the terminal measured as described above will be described with reference to the flowcharts of FIGS. 4 and 5.

First, FIG. 4 is a flowchart illustrating a handoff process between heterogeneous wireless communication systems according to an embodiment of the present invention, which relates to handoff in an area in which only system A and system B coexist.

Hereinafter, for convenience of explanation, the signal strength at the time A starts various procedures for handoff is referred to as P_1, the lowest signal strength including System B in the handoff candidate set is referred to as P_2, and P_3 as the system. It is assumed that the lowest serviceable signal strength of A, that is, the signal strength at the time of handoff.

As shown, in the region where the two wireless communication systems of system A and system B coexist, the signal strength of system A (P _A ) as the mobile communication terminal, which is being serviced by system A (S101), moves to the system B side. Determines whether P_1 or less, or whether the signal strength (P _B ) of the system B is more than or equal to P_3 (S102).

As a result of the determination, when the signal strength of the system A becomes less than or equal to P_1 or the signal strength of the system B becomes greater than or equal to P_3, the moving speed V of the mobile communication terminal is periodically measured (S103).

Subsequently, when the signal strength of the system A is continuously lowered and the signal strength of the system B is continuously increased, and it is time to select a handoff candidate, the measured moving speed V of the mobile communication terminal is determined by the system B. It is determined whether or not the supportable moving speed SV _B (S104). If the measured moving speed of the mobile communication terminal is equal to or less than the supportable moving speed SV _{B of} the system B, the system B is a handoff candidate system. (S105).

Next, if the system B is selected as the candidate system, it is determined whether the signal strength of the system A is equal to or less than P_3 and at the same time whether the signal strength of the system B is equal to or larger than P_2, that is, whether or not the handoff time is reached (S106).

As a result of the determination in step S106, if the signal strength of the system A is not less than P_3 or if the signal strength of the system B is not more than P_2, it is determined whether the signal strength measurement allowable time (ST) has passed. (S107), if the signal strength measurement allowable time has not elapsed, it is returned to the step S106 to determine whether the handoff is possible to the system continuously, and when the signal strength measurement allowable time has elapsed, the adjacent cell in the system A itself is passed. Handoff is performed (S109).

When the signal strength of the system A is less than or equal to P_3 and the signal strength of the system B is greater than or equal to P_2 as a result of the determination in S106, a handoff to the system B is performed (S108).

On the other hand, as a result of the determination in step S102, when the signal strength of the system A is not less than P_1 and at the same time the signal strength of the system B is not more than P_3 (prediction of handoff is not the time to measure the speed of the terminal Case), it is returned to the first step to continuously determine whether or not it is time to measure the speed of the terminal.

When the measured moving speed V of the mobile communication terminal is not equal to or less than the supportable moving speed SV _{B of} the system B, handoff is performed to the system B only by considering the signal strength. If so, since the transmission quality may deteriorate, handoff should be performed to an adjacent cell in the system A itself (S109).

Finally, FIG. 5 is a flowchart illustrating a handoff process between heterogeneous wireless communication systems according to another embodiment of the present invention, in which System A and System 1 to System in a region where a plurality of wireless communication systems of System 1 and N coexist. A method for performing handoff with any of N.                     

As described above, in this embodiment, the signal strength at the time when A starts the overall procedure for handoff is called P_1, and the lowest signal that selects any system n from system 1 to system N as a handoff candidate set. The strength is referred to as P_2, and P_3 is referred to as the lowest serviceable signal strength of system A, that is, the signal strength at the time of handoff.

As shown, in order to perform a procedure for handoff as the mobile communication terminal which is being serviced by the system A (S201) moves, the signal strength of the system A becomes P_1 or less, or the signal strength of the system B is P_3. If it is determined whether or not the abnormality (S202), the signal strength of the system A is equal to or less than P_1, or if the signal strength of any system n of the system 1 to system N is equal to or greater than P_3, the moving speed of the mobile communication terminal It measures (S203).

Next, it is determined whether the measured moving speed V of the mobile communication terminal is equal to or less than the supportable moving speed SV _n of the corresponding system n (S204). The candidate system is selected (S205).

Subsequently, it is determined whether the signal strength of the system A is equal to or less than P_3, and at the same time whether the signal strength of the system n is equal to or greater than P_2 (S206), and the signal strength of the system A is equal to or less than P_3 and at the same time the signal strength of the system n is equal to or greater than P_2. If it is, handoff to the system n is performed (S207).                     

On the other hand, in the embodiment of FIG. 5, since a plurality of systems coexist, other systems may be selected as candidate systems if the arbitrary system n is not selected as a candidate system unlike in FIG. 4.

Therefore, when the moving speed of the measured mobile communication terminal in the S204 step system n supportable movement speed is not less than (SV _n) of, as in Example 4, rather than performing handoff to the system A, again After returning to step S202 and performing another step S202 of any one of the system 1 to system N except the system n, a handoff to another system is considered.

Further, after the step S206, if the signal strength of the system A is not less than P_3 or if the signal strength of the system n is not more than P_2, it is determined whether the signal strength measurement allowable time has elapsed (S207), If the signal strength measurement allowable time has not elapsed, the process returns to the fifth step, and when the signal strength measurement allowable time has elapsed, it is determined whether there is another system capable of performing handoff among the systems 1 to n. S209).

As a result of the determination, if another system exists, the first step is performed again for the corresponding other wireless communication system among the system 1 to system N, and if there is no other system to be considered for handoff further, the system A Handoff is performed to an adjacent cell in itself (S210).

Meanwhile, in steps S103 and S203, in which the moving speed of the terminal is measured in the embodiments of FIGS. 4 and 5, the moving speed of the terminal is determined by one of a round trip delay (RTD) and a propagation delay (Propagation Delay). The measurement may be performed using the GPS location information or the GPS location information, and the moving speed measurement method of the terminal is not limited thereto.

In addition, the overall process of measuring the movement speed of the terminal for handoff and handoff according to the present invention may be performed by the mobile communication terminal or by the base station, and is performed by only one of the terminal and the base station. It is not limited.

As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above should be understood as illustrative and not restrictive in all aspects. Should be. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Therefore, according to the handoff method between heterogeneous wireless communication systems using the moving speed of the mobile communication terminal of the present invention, the terminal moving speed support standard by performing the handoff by additionally utilizing the moving speed of the terminal as well as the received signal strength. There is an advantage that the problem of transmission quality deterioration by applying the handoff method considering only received signal strength between different heterogeneous wireless communication systems can be solved, and handoff between heterogeneous wireless communication systems can be made according to the environment. There is an effect that the service can be received in a better connection environment.

Claims (10)

As a handoff method between heterogeneous wireless communication systems as a mobile communication terminal receiving a service of System A moves to System B in an area where two wireless communication systems of System A and System B coexist, The signal strength at the time System A starts the overall procedure for handoff is called P_1, the lowest signal strength including System B in the handoff candidate set is called P_2, and P_3 is the lowest serviceable signal strength of System A. That is, when the signal strength at the time when the handoff should be A first step of determining whether the signal strength of system A is equal to or less than P_1 or whether the signal strength of system B is equal to or greater than P_3; A second step of measuring a moving speed of the mobile communication terminal when the signal strength of the system A becomes less than or equal to P_1 or the signal strength of the system B becomes greater than or equal to P_3 as a result of the determination in the third step; A third step of determining whether the measured moving speed of the mobile communication terminal is less than or equal to the supportable moving speed of the system B; A fourth step of selecting the system B as a handoff candidate system when the measured moving speed of the mobile communication terminal is less than or equal to the supportable moving speed of the system B; A fifth step of determining whether the signal strength of the system A is less than or equal to P_3 and at the same time whether the signal strength of the system B is greater than or equal to P_2; A sixth step of performing a handoff to the system B when the signal strength of the system A is less than or equal to P_3 and the signal strength of the system B is greater than or equal to P_2; Handoff method between heterogeneous wireless communication system using the moving speed of the mobile communication terminal, characterized in that consisting of. The method of claim 1, The second step, And as a result of the determination of the first step, if the signal strength of the system A is not less than P_1 and at the same time the signal strength of the system B is not more than P_3, the method further includes the step of returning to the first step. A handoff method between heterogeneous wireless communication systems using a moving speed of a mobile communication terminal. The method of claim 1, After the third step, Performing a handoff to a neighbor cell in the system A itself when the measured movement speed of the mobile communication terminal is not less than or equal to the supportable movement speed of the system B; The handoff method between heterogeneous wireless communication systems using the moving speed of the mobile communication terminal further comprising. The method of claim 1, After the fifth step, Determining whether the signal strength measurement time has elapsed when the signal strength of the system A is not equal to or less than P_3 or the signal strength of the system B is not equal to or greater than P_2; If the signal strength measurement time has not passed, returning to the fifth step, and when the signal strength measurement time has passed, performing a handoff to an adjacent cell in the system A itself; The handoff method between heterogeneous wireless communication systems using the moving speed of the mobile communication terminal further comprising. In an area where system A and a plurality of wireless communication systems of systems 1 to N coexist, heterogeneous wireless communication for performing handoff to any of systems 1 to N as the mobile communication terminal receiving the service of system A moves. As a method of handoff between systems, The signal strength at the time System A starts the procedure for handoff is called P_1, the lowest signal strength including any system n from System 1 to System N in the handoff candidate set is called P_2, and P_3 is system When the serviceable minimum signal strength of A, that is, the signal strength at the time of handoff, A first step of determining whether the signal strength of system A is equal to or less than P_1 or whether the signal strength of system n is equal to or greater than P_3; A second step of measuring a moving speed of the mobile communication terminal when the signal strength of the system A becomes less than or equal to P_1 or the signal strength of any of the systems n of the system 1 to system P is equal to or greater than P_3; Determining whether the measured moving speed of the mobile communication terminal is less than or equal to the supportable moving speed of system n; A fourth step of selecting the system n as a handoff candidate system when the measured moving speed of the mobile communication terminal is less than the supportable moving speed of system n; A fifth step of determining whether the signal strength of the system A is equal to or less than P_3 and at the same time whether the signal strength of the system n is equal to or larger than P_2; A sixth step of performing a handoff to the system n when the signal strength of the system A is less than or equal to P_3 and the signal strength of the system n is greater than or equal to P_2 as a result of the determination in the fifth step; Handoff method between heterogeneous wireless communication system using the moving speed of the mobile communication terminal, characterized in that consisting of. The method of claim 5, The second step, And as a result of the determination of the first step, returning to the first step if the signal strength of the system A is not less than P_1 and at the same time the signal strength of the system n is not more than P_3. A handoff method between heterogeneous wireless communication systems using a moving speed of a mobile communication terminal. The method of claim 5, After the third step, As a result of the determination in the third step, if the measured moving speed of the mobile communication terminal is not less than the supportable moving speed of the system n, the first step may be performed with respect to any other wireless communication system of the system 1 to the system N. A handoff method between heterogeneous wireless communication systems using a moving speed of a mobile communication terminal. The method of claim 5, After the fifth step, Determining whether the signal strength measurement time has elapsed when the signal strength of the system A is not less than P_3 or the signal strength of the system n is not greater than or equal to P_2 as a result of the determination in the fifth step; If the signal strength measurement allowable time has not passed, returning to the fifth step, and if the signal strength measurement allowable time has elapsed, determining whether there is another system capable of performing handoff among the systems 1 to n. Wow; As a result of determining whether the other system exists, if the other system exists, the first step is performed for the corresponding other wireless communication system among the system 1 to system N, and if the other system does not exist, Performing a handoff to an adjacent cell; The handoff method between heterogeneous wireless communication systems using the moving speed of the mobile communication terminal further comprising. 6. The method according to claim 1 or 5, The second step, A handoff between the heterogeneous wireless communication systems using the mobile speed of the mobile communication terminal, wherein the mobile speed is measured by using one of a round trip delay (RTD) and a propagation delay value; Way. 6. The method according to claim 1 or 5, The second step, A method for handoff between heterogeneous wireless communication systems using the movement speed of the mobile communication terminal, characterized in that the step of measuring the movement speed of the mobile communication terminal using GPS location information.

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