KR101078140B1 - Method for selecting base station for seamless handoff of intelligent wireless transmit/receive unit - Google Patents

Abstract

A method for selecting a base station for seamless handoff of an intelligent mobile terminal according to an embodiment of the present invention comprises the steps of: receiving base station information from a base station information management server and storing it in a memory in the mobile terminal; Using the base station information stored in the memory, querying a first radio access technology (RAT) associated with the mobile terminal for the presence of an available channel; And selecting a base station corresponding to an optimal third RAT from among the second RATs in which the available channel exists and performing communication.

Handoff, Intelligent Mobile Terminal, Base Station Selection, RAT, GPS, USIM

Description

Base station selection method for seamless handoff of intelligent mobile terminal {METHOD FOR SELECTING BASE STATION FOR SEAMLESS HANDOFF OF INTELLIGENT WIRELESS TRANSMIT / RECEIVE UNIT}

Embodiments of the present invention relate to a method of selecting a base station for seamless handoff of an intelligent mobile terminal.

The present invention is derived from a study conducted as part of the IT source technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Communication Research and Development. [Task management number: 2008-F-001-01, Task name: Environmental adaptation of wireless communication method of mobile communication Type autonomous control technology].

Currently, wireless access systems configure each network to provide specific applications. Existing wireless access systems include wireless local area networks (WLANs), cellular networks including second generation third generation, and other radio access systems such as Long Term Evolution (LTE) and fourth generation.

When these mixed networks exist in a multicell environment, when users of such networks move from one network to another, there is a need for seamless connectivity support for the mobile terminal (WTRU). If a mobile terminal (WTRU) is capable of supporting a plurality of heterogeneous networks, it is required to seamlessly perform handoff between these networks for continuous service provision and radio resource utilization.

To this end, studies on a network structure for downloading information using a separate channel such as a common pilot channel (CPC) and handoff techniques related thereto are being conducted. However, each network has a connection technology, and even a homogeneous network raises a problem of using a common channel (CPC) in an environment in which a plurality of operators are divided.

SUMMARY OF THE INVENTION The present invention has been made to improve the prior art as described above, and an object of the present invention is to enable a seamless handoff of a mobile terminal by selecting an optimal base station using GPS information.

An object of the present invention is to reduce the time required for channel scanning by using GPS information and base station information.

The present invention can continuously update the base station information to shorten the time required for handoff, thereby reducing the number of packets that fail to communicate in a weak communication zone, and completing handoff after the start of handoff. It is an object of the present invention to reduce an amount of untransmitted data due to buffering of a previous base station.

The object of the present invention is not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object and to solve the problems of the prior art, a method for selecting a base station for seamless handoff of an intelligent mobile terminal according to an embodiment of the present invention receives the base station information from the base station information management server memory in the mobile terminal; Storing in; Using the base station information stored in the memory, querying a first radio access technology (RAT) associated with the mobile terminal for the presence of an available channel; And selecting a base station corresponding to an optimal third RAT from among the second RATs in which the available channel exists and performing communication.

Receiving the base station information from the base station information management server and storing in the memory in the mobile terminal, country code, multi-cell number, location coordinates of the base station, access technology, available channel number of the access technology, available channel of the access technology Sorting the base station information including at least one of a frequency or a minimum quality of service (QoS) available in an available channel according to a preset criterion; And storing the sorted base station information in a database in a base station information management table in the memory.

Using the base station information stored in the memory, inquiring of the presence of an available channel to the first RAT associated with the mobile terminal, using the GPS module mounted on the mobile terminal, the location coordinates of the mobile terminal Recognizing periodically; Recognizing a country code and a multi-cell number using the recognized location coordinates; Retrieving N (natural numbers) first available RATs from the memory using the recognized country code and the multi-cell number within the range of the multi-cell corresponding to the mobile terminal; And inquiring whether an available channel exists in the searched N first RATs.

The performing of communication by selecting a base station corresponding to an optimal third RAT from among the second RATs in which the available channel exists includes selecting the third RAT in consideration of the frequency strength of the available channel among the second RATs. Specifying; And selecting a base station corresponding to the designated third RAT to perform communication.

According to another embodiment of the present invention, a method for selecting a base station for seamless handoff of an intelligent mobile terminal may include: recognizing a location coordinate of a mobile terminal periodically and recognizing a first multicell number corresponding to the location coordinate; If the recognized first multicell number and the previous second multicell number stored in a memory in the mobile terminal are the same, determining whether the mobile terminal is located in a communication safe zone or a communication weak spot; And when the mobile terminal is located in the communication safety zone, receiving base station information of the base station corresponding to the first RAT associated with the mobile terminal from a base station information management server and storing the base station information in the memory.

According to another exemplary embodiment of the present invention, a method for selecting a base station for seamless handoff of an intelligent mobile terminal is based on information associated with the mobile terminal by using base station information stored in the memory when the mobile terminal is located in the weak communication zone. Querying the first RAT for the presence of an available channel; And selecting a base station corresponding to an optimal third RAT from among the second RATs in which the available channel exists and performing communication.

The base station selection method for seamless handoff of an intelligent mobile terminal according to another embodiment of the present invention uses the base station information stored in the memory when the first multicell number and the second multicell number are different. Retrieving N (natural numbers) first RATs available from the memory within a range of multiple cells corresponding to a mobile terminal; Inquiring whether an available channel exists in the searched N first RATs; And selecting a base station corresponding to an optimal third RAT from among the second RATs in which the available channel exists and performing communication.

The determining of whether the mobile terminal is located in a communication safe zone or a weak communication zone may include using the received signal strength (RSSI) received from the first RAT available within a range of multiple cells corresponding to the mobile terminal. The method may include determining whether the mobile terminal is located in a communication safe zone or a communication weak spot.

According to another embodiment of the present invention, a method for selecting a base station for seamless handoff of an intelligent mobile terminal may include: recognizing a location coordinate of a mobile terminal periodically and recognizing a first multicell number corresponding to the location coordinate; If the recognized first multicell number and the previous second multicell number stored in the memory in the mobile terminal are the same, whether the channel performance with the base station of the first RAT associated with the mobile terminal satisfies a preset reference value. Determining; And when the channel performance satisfies the reference value, receiving base station information of the base station corresponding to the first RAT from a base station information management server and storing the base station information in the memory.

A base station selection method for seamless handoff of an intelligent mobile terminal according to another embodiment of the present invention corresponds to the mobile terminal using base station information stored in the memory when the channel performance does not satisfy the reference value. Retrieving N (natural numbers) first RATs available in the memory from the memory; Inquiring whether an available channel exists in the searched N first RATs; And selecting a base station corresponding to an optimal third RAT from among the second RATs in which the available channel exists and performing communication.

Specific details of other embodiments are included in the detailed description and the accompanying drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and those skilled in the art to which the present invention pertains. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

According to embodiments of the present invention, by selecting an optimal base station using GPS information, it is possible to perform a seamless handoff of the mobile terminal.

According to embodiments of the present invention, the time required for channel scanning can be shortened using GPS information and base station information.

According to embodiments of the present invention, it is possible to continuously update the base station information to shorten the time required for handoff, thereby reducing the number of packets that fail to communicate in the weak communication zone, and also the hand The amount of untransmitted data according to the buffering of the previous base station may be reduced from the off start until the handoff is completed.

As used herein, the term wireless transmitter receiver unit (WTRU) includes user equipment (UE), mobile station, fixed / mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment. It is not limited to these. In addition, the mobile terminal (WTRU) can communicate with two or more access technologies and base stations at the same time, and position recognition using a Global Positioning System (GPS) module.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating an example of a multicell structure applied to an embodiment of the present invention.

As shown in FIG. 1, WLANs 101 and 102 are arranged with the smallest cell radius, and Global System for Mobile (GSM) 103 and 104 having greater coverage are selected from the wireless LAN. It is arrange | positioned with the cell radius larger than (101, 102). For reference, FIG. 1 illustrates one example of a multicell, and the multicell may include various types of cells as many as the type of the mobile terminal.

In the multi-cell as shown in FIG. 1, when a mobile terminal is powered on and attempts to stand by in communication with any base station, the mobile terminal uses which access technology and which of the base stations or access points (APs) support the access technology. You can make a decision about whether to choose one. Detailed description thereof will be described later with reference to FIG. 4.

The handoff procedure can be divided into channel scanning, authentication, and reassociation. The procedure that takes up the most time and consumes the most power can be called channel scanning. Therefore, in the embodiment of the present invention, by performing the handoff using GPS, it is possible to reduce the time delay caused by channel scanning.

2 is a diagram illustrating an example of a method for storing information about a base station available in a memory in a universal subscriber identity module (USIM) of a mobile terminal according to an embodiment of the present invention.

As shown in FIG. 2, the mobile terminal 201 is connected to the base station information management server 202 through a wired cable such as a universal serial bus (USB), and the base station 203 is connected to the base station information management server 202. Base station information such as configuration information and recommended channel number or available channel number is downloaded and stored in a memory in the USIM of the mobile terminal 201.

In this case, the mobile terminal 201 may update the base station information stored in the memory. That is, the mobile terminal 201 may update the base station information stored in the memory through wired or wireless. The update via wire can be made by the user manually connecting the mobile terminal 201 to the base station information management server 202, and the update via wireless is automatically moved from each corresponding base station 203. It may be made based on the base station information collected by the terminal 201.

As mentioned above, the mobile terminal owns an internal storage memory such as USIM. The memory may store fixed base station information, for example, location information of cellular network base stations such as GSM base station and E-UTRAN base station, available information history, and the like. Location information of the AP of the network corresponding to the access point (WLAN AP) or the like, access technology, and history of available channel information of the access technology may be stored.

The mobile terminal aligns the base station information using a predetermined criterion, for example, user preference and quality of service (QoS) support capability and the like, and stores the information in a database. At this time, the mobile terminal can arrange the base station information from the top to the bottom in the order of high priority.

3 is a diagram illustrating an example of base station information stored in a memory of a mobile terminal according to an embodiment of the present invention.

As shown in FIG. 3, the base station information management table includes country code 301, multicell number 302, priority 303, location coordinates 304, access technology 305, channel number / channel frequency ( 306, provideable minimum QoS 307, and the like.

The mobile terminal recognizes the country code 301 and the multi-cell number 302 based on its location and records them in the base station information management table. At this time, the country code 301 and the multi-cell number 302 may be used to start the access technology and communication using the access technology.

The mobile terminal determines the priority 303 based on the history and the preference of the user. The mobile terminal determines an access technology (RAT) corresponding to each of the determined priorities 303 and an available channel number or channel frequency of the access technology. The priority 303 is recorded in the base station information management table.

The mobile station can find the RAT 305 and the available channel number 306 at the radius of the multicell using the location of the base station. At this time, the position coordinate 304, the RAT 305, and the available channel number 306 of the base station are recorded in the base station information management table.

The mobile station records the minimum quality of service (QoS) 307 that can be provided in the corresponding channel in the base station information management table, so as to determine whether the requirements of the user and the application are satisfied and to update the table more quickly. In addition, when the mobile terminal related technology is actually implemented, the mobile terminal may make some changes such as storing additional information in the base station information management table or deleting unnecessary items.

4 is a flowchart illustrating a method for selecting a base station for seamless handoff of an intelligent mobile terminal according to an embodiment of the present invention. FIG. 4 is a diagram corresponding to a case in which a mobile station starts to register with a base station due to power on or another reason in any region of FIG. 1. Here, the base station selection method may be implemented by the mobile terminal 201 of FIG.

Referring to FIG. 4, in step S401, the mobile terminal powers on. Before the mobile terminal is turned on, it is preferable that the mobile station first receives base station information from the base station information management server and stores the base station information in the internal memory USIM.

That is, the mobile terminal includes a country code, a multi-cell number, a location coordinate of a base station, an access technology, an available channel number of the access technology, an available channel frequency of the access technology, and a minimum quality of service (QoS) available in the available channel. The base station information is sorted according to preset criteria (user preference, QoS support capability, etc.), and the database information is stored in the base station information management table in the memory.

Next, the mobile terminal uses the base station information stored in the memory to query the Radio Access Technology (RAT) associated with the mobile terminal for the presence of an available channel.

That is, in step S402, the mobile terminal periodically recognizes the position coordinates of the mobile terminal by using the GPS module mounted therein. In step S403, the mobile terminal recognizes the country information (number) and the multicell number using the recognized location coordinates. In step S404, the mobile terminal reads the memory (USIM) information, that is, the base station information, based on the recognition information, that is, the country information and the multicell number. In step S405, the mobile station uses the base station information including the recognized country code and the multi-cell number to obtain N (natural numbers) RATs available within the range of the multi-cell corresponding to the mobile terminal from the memory. Search and query whether an available channel exists.

Here, the N available RATs are RATs up to rank N arranged based on the history (base station information) stored in the USIM. When the mobile station is a fixed base station (for example, GSM, etc.) of the RATs up to alignment order N, the mobile station performs an access request for the presence of an available channel to the fixed base station, and the base station (for example, where mobility exists) WLAN), a connection request is performed to the base station where the mobility exists, inquiring whether the base station exists and whether there is an available channel.

Next, the mobile station designates a RAT in which the available channel exists among the N RATs, and selects a base station corresponding to an optimal RAT from the designated RATs to perform communication.

That is, in step S406, the mobile terminal receives a response (information on whether there is an available channel) from the corresponding base station, that is, the base station corresponding to the RAT in which the available channel exists. In step S407, the mobile terminal selects the corresponding base station and channel of the best RAT from the response result and starts communication. That is, the mobile terminal designates the optimal RAT by using the frequency strength of the available channel, and selects a base station corresponding to the designated optimal RAT to perform communication.

In step S408, the mobile terminal performs an operation of updating the USIM information. The mobile terminal may perform step S407 and step S408 simultaneously.

Meanwhile, the mobile terminal reports the collected channel information to the base station, so that the base station can continuously observe the channel state. The APs may send information to the terminal by referring to the AP information table in the corresponding multicell held by the APs using communication between the APs.

5 is a flowchart illustrating a method for selecting a base station for seamless handoff of an intelligent mobile terminal according to another embodiment of the present invention. Here, the base station selection method may be implemented by the mobile terminal 201 of FIG.

Referring to FIG. 5, in step S501, the mobile terminal periodically recognizes its location coordinates. In step S502, the mobile terminal recognizes a multicell number (first multicell number) corresponding to the location coordinates.

In step S503, the mobile terminal compares the recognized first multicell number with a previous second multicell number stored in a memory within the mobile terminal.

As a result of the comparison, when the first multicell number and the second multicell number are the same (Y direction in S503), in step S504, the mobile terminal determines whether the mobile terminal is located in a weak communication zone.

At this time, the mobile terminal receives the received signal from the available RAT within the range of the multi-cell to which it belongs, and using the strength of the received received signal (RSSI), whether the mobile terminal is located in a weak communication zone or a communication safety zone You can judge.

As a result of determination, when located in the weak communication zone (Y direction of S504), the mobile terminal reads the USIM (internal memory) information, that is, the base station information in step S505, and then using the base station information in step S506 The N (natural number) RATs available within the range of multiple cells corresponding to the mobile terminal are searched from the memory to inquire whether an available channel exists.

Here, the N available RATs are RATs up to rank N arranged based on the history (base station information) stored in the USIM. When the mobile station is a fixed base station (for example, GSM, etc.) of the RATs up to alignment order N, the mobile station performs an access request for the presence of an available channel to the fixed base station, and the base station (for example, where mobility exists) WLAN), a connection request is performed to the base station where the mobility exists, inquiring whether the base station exists and whether there is an available channel.

In step S507, the mobile terminal receives a response to the query (information on the available channel) from the corresponding base station, that is, the base station corresponding to the RAT in which the available channel exists. In step S508, the mobile terminal selects the corresponding base station and channel of the best RAT from the response result and starts communication. That is, the mobile terminal designates the optimal RAT by using the frequency strength of the available channel, and selects a base station corresponding to the designated optimal RAT to perform communication.

In step S509, the mobile terminal performs an operation of updating the USIM information. The mobile terminal may perform step S508 and step S509 simultaneously.

On the other hand, if the first multicell number is different from the second multicell number as a result of the comparison (N direction in S503), the mobile terminal performs steps S505 to S509.

On the other hand, the determination result, if not located in the communication weak zone (N direction of S504), that is, if located in the communication safety zone, the mobile terminal in step (S510) of the base station corresponding to each of the RAT associated with the mobile terminal The base station information management server requests information (base station information) about the position and status.

In step S511, the mobile terminal receives base station information corresponding to each RAT received in response to the request. In step S512, the mobile terminal rearranges the priorities in the USIM and stores the received information (base station information). In step S509, the mobile terminal updates USIM information, i.e., base station information.

6 is a flowchart illustrating a method of selecting a base station for seamless handoff of an intelligent mobile terminal according to another embodiment of the present invention. Here, the base station selection method may be implemented by the mobile terminal 201 of FIG.

Referring to FIG. 6, in step S601, the mobile terminal periodically recognizes its location coordinates. In step S602, the mobile terminal recognizes a multicell number (first multicell number) corresponding to the location coordinates.

In step S603, the mobile terminal compares the recognized first multicell number with a previous second multicell number stored in a memory in the mobile terminal.

As a result of the comparison, when the first multi-cell number and the second multi-cell number are the same (Y direction in S603), in step S604, the mobile station determines a base station corresponding to an available RAT within a range of the multi-cell to which it belongs. It is determined whether the channel performance of satisfies a preset reference value.

That is, the mobile terminal includes information on the channel performance such as channel quality indicator (CQI), signal-to-noise ratio (SNR), bit error ratio (BER), and packet error ratio (PER). It can be determined whether it meets the requirements (reference values). Here, the requirements may be preset manually or automatically, and may include reference levels such as CQI, SNR, BER, PER, and the like.

As a result of determination, if the channel performance is lower than or equal to the reference value (Y direction in S604), the mobile terminal reads USIM (internal memory) information, that is, base station information in step S605, and then the base station in step S606. Using the information, N (natural numbers) RATs available within a range of multiple cells corresponding to the mobile terminal are searched from the memory to inquire whether an available channel exists.

Here, the N available RATs are RATs up to rank N arranged based on the history (base station information) stored in the USIM. When the mobile station is a fixed base station (for example, GSM, etc.) among the RATs up to alignment order N, the mobile station performs an access request to ask the fixed base station whether there is an available channel, and the base station (for example, where mobility exists) , WLAN), the access request is performed to the base station where the mobility exists, inquiring whether the base station exists and whether there is an available channel.

In step S607, the mobile terminal receives a response (information on availability of available channel) from the corresponding base station, that is, the base station corresponding to the RAT in which the available channel exists. In step S608, the mobile terminal selects the corresponding base station and channel of the best RAT from the response result and starts communication. That is, the mobile terminal designates the optimal RAT by using the frequency strength of the available channel, and selects a base station corresponding to the designated optimal RAT to perform communication.

In step S609, the mobile terminal performs an operation of updating the USIM information. The mobile terminal may perform step S608 and step S609 simultaneously.

On the other hand, if the first multi-cell number and the second multi-cell number is different as the result of the comparison (N direction in S603), the mobile terminal performs steps S605 to S609.

On the other hand, as a result of the determination, when the channel performance is larger than the reference value (N direction of S604), that is, when information such as CQI, SNR, BER, PER, etc. does not meet the requirements (reference value) of the mobile terminal, step ( In step S610, the mobile terminal requests the base station information management server for information (base station information) regarding the location and status of the base station corresponding to each of the RATs within the multi-cell range to which it belongs.

In step S611, the mobile terminal receives base station information corresponding to each RAT received in response to the request. In step S612, the mobile terminal rearranges the priorities in the USIM and stores the received information (base station information). In step S609, the mobile terminal updates USIM information, that is, base station information.

Embodiments of the present invention include computer readable media including program instructions for performing various computer implemented operations. The computer readable medium may include program instructions, local data files, local data structures, or the like, alone or in combination. The media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical recording media such as CD-ROMs, DVDs, magnetic-optical media such as floppy disks, and ROM, RAM, flash memory, and the like. Hardware devices specifically configured to store and execute the same program instructions are included. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like.

While specific embodiments of the present invention have been described so far, various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below, but also by the equivalents of the claims.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will belong to the scope of the present invention.

1 is a diagram illustrating an example of a multicell structure applied to an embodiment of the present invention.

2 is a diagram illustrating an example of a method for storing information about a base station available in a memory in a universal subscriber identity module (USIM) of a mobile terminal according to an embodiment of the present invention.

3 is a diagram illustrating an example of base station information stored in a memory of a mobile terminal according to an embodiment of the present invention.

4 is a flowchart illustrating a method for selecting a base station for seamless handoff of an intelligent mobile terminal according to an embodiment of the present invention.

5 is a flowchart illustrating a method for selecting a base station for seamless handoff of an intelligent mobile terminal according to another embodiment of the present invention.

6 is a flowchart illustrating a method of selecting a base station for seamless handoff of an intelligent mobile terminal according to another embodiment of the present invention.

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

201: mobile terminal

202: base station information management server

203: base station

204: access point (AP)

Claims (10)

Receiving base station information from a base station information management server and storing the base station information in a memory in the mobile terminal; Using the base station information stored in the memory, querying a first radio access technology (RAT) associated with the mobile terminal for the presence of an available channel; And Performing communication by selecting a base station corresponding to an optimal third RAT from the second RATs in which the available channel exists; Including, Inquiring whether the available channel exists, Periodically recognizing position coordinates of the mobile terminal by using the GPS module mounted in the mobile terminal; Recognizing a country code and a multi-cell number using the recognized location coordinates; Retrieving N (natural numbers) first available RATs from the memory using the recognized country code and the multi-cell number within the range of the multi-cell corresponding to the mobile terminal; And Querying whether there are available channels in the searched N first RATs A base station selection method for seamless handoff of an intelligent mobile terminal comprising a. The method of claim 1, Receiving base station information from the base station information management server and storing in the memory in the mobile terminal, At least one of a country code, a multi-cell number, a location coordinate of a base station, an access technology, an available channel number of the access technology, an available channel frequency of the access technology, or a minimum quality of service (QoS) available on the available channel. Sorting the base station information according to a preset criterion; And Storing the sorted base station information in a database in a base station information management table in the memory; A base station selection method for seamless handoff of an intelligent mobile terminal comprising a. delete The method of claim 1, In the second RAT where the available channel exists, the step of performing communication by selecting a base station corresponding to the optimal third RAT, Designating, from the second RAT, the third RAT in consideration of the frequency strength of the available channel; And Selecting a base station corresponding to the designated third RAT to perform communication; A base station selection method for seamless handoff of an intelligent mobile terminal comprising a. Periodically recognizing location coordinates of the mobile terminal and recognizing a first multicell number corresponding to the location coordinates; If the recognized first multicell number and the previous second multicell number stored in a memory in the mobile terminal are the same, determining whether the mobile terminal is located in a communication safe zone or a communication weak spot; And When the mobile terminal is located in the communication safety zone, receiving base station information of the base station corresponding to the first RAT associated with the mobile terminal from a base station information management server and storing the base station information in the memory; A base station selection method for seamless handoff of an intelligent mobile terminal comprising a. The method of claim 5, If the mobile terminal is located in the communication weak zone, Using the base station information stored in the memory, querying a first RAT associated with the mobile terminal for the presence of an available channel; And Performing communication by selecting a base station corresponding to an optimal third RAT from the second RATs in which the available channel exists; The base station selection method for a seamless handoff of the intelligent mobile terminal further comprising. The method of claim 5, If the first multi-cell number and the second multi-cell number is different, Using the base station information stored in the memory, retrieving N (natural numbers) first RATs available from the memory within a range of multiple cells corresponding to the mobile terminal; Inquiring whether an available channel exists in the searched N first RATs; And Performing communication by selecting a base station corresponding to an optimal third RAT from the second RATs in which the available channel exists; The base station selection method for a seamless handoff of the intelligent mobile terminal further comprising. The method of claim 5, Determining whether the mobile terminal is located in a communication safe zone or a communication weak zone, Determining whether the mobile terminal is located in a communication safe zone or a weak communication zone by using a strength (RSSI) of a received signal received from the first RAT available within a range of multiple cells corresponding to the mobile terminal; A base station selection method for seamless handoff of an intelligent mobile terminal comprising a. Periodically recognizing location coordinates of the mobile terminal and recognizing a first multicell number corresponding to the location coordinates; Comparing the recognized first multicell number with a previous second multicell number stored in a memory in the mobile terminal to the channel performance of the base station of the first RAT associated with the mobile terminal and a preset reference value. ; And When the channel performance is greater than the reference value, receiving base station information of the base station corresponding to the first RAT from a base station information management server and storing the base station information in the memory. A base station selection method for seamless handoff of an intelligent mobile terminal comprising a. 10. The method of claim 9, When the channel performance is lower than or equal to the reference value, the N (natural number) first RATs available within the range of the multicell corresponding to the mobile terminal are searched from the memory using base station information stored in the memory. step; Inquiring whether an available channel exists in the searched N first RATs; And Performing communication by selecting a base station corresponding to an optimal third RAT from the second RATs in which the available channel exists; The base station selection method for a seamless handoff of the intelligent mobile terminal further comprising.

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