KR20070011698A - Roaming service method of a mobile communication terminal, the mobile communication terminal and the mobile communication system - Google Patents

Abstract

The present invention stores a base station broadcasting a list of roaming neighboring systems in a corresponding region, and a preferred roaming list (PRL) consisting of a home system and a roaming system, and scans a home system scanned through a base station scan. A mobile communication terminal that receives a list of neighboring roaming systems from the base station, selects roaming systems in the neighboring system list from the preferred roaming list, and sequentially scans only the base stations of the selected roaming system when roaming service is requested. It provides a mobile communication system comprising a.

According to the present invention, when the mobile communication terminal searches only a roaming system selected from the PRL when searching for a radio channel to perform a roaming service, a roaming system capable of roaming service capable of roaming in a corresponding region among all roaming systems in the PRL is searched. By being able to preferentially scan, the roaming system scan time for roaming can be shortened, and the success rate of roaming system scan can be increased.

Description

Roaming service method of a mobile terminal, the mobile terminal and the mobile communication system TECHNICAL FIELD

1 is a block diagram of a mobile communication system according to an embodiment of the present invention;

2 is a block diagram of a mobile communication terminal for explaining performing a roaming service in a mobile communication terminal according to an embodiment of the present invention;

3 and 4 are flowcharts of performing a roaming service in a mobile communication terminal according to an embodiment of the present invention.

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

10: base station of the home system 20,30,40,50: base station of the roaming system

100: mobile communication terminal 110: memory

111: ROM 112: flash memory

113: RAM 120: control unit

130: RF unit 140: voice processing unit

150: speaker 160: microphone

170: key input unit 180: display unit

The present invention relates to a roaming service of a cellular mobile communication system, and more particularly, a base station broadcasts information of a neighboring system capable of roaming service in a corresponding area to each mobile communication terminal so that the mobile communication terminal can provide roaming service. The present invention relates to a roaming service method of a mobile communication terminal, a mobile communication terminal, and a mobile communication system that first search for roaming serviceable neighbor systems in a corresponding area when searching a wireless channel for performing.

Wireless communication networks, including fixed wireless and cellular type mobile communication networks, continue to evolve. Including code division multiple access (CDMA), time division multiple access (TDMA), pan-European cellular mobile communication system (GSM), advanced mobile phone system (AMPS) and digital AMPS (D-AMPS) (IS-135 TDMA) There are many available technologies for providing wireless communication.

When the subscriber of the mobile terminal has a use contract with a specific service provider A, the system of this service provider A is called a home system, and the service provider A has a roaming agreement with other service providers. For this reason, a system that a subscriber can use through a roaming service is called a roaming system.

Therefore, the mobile communication terminal uses the preferred roaming list (PRL) stored in the mobile communication terminal when the signal of the home system is less than the threshold or needs to acquire the roaming system for other reasons. Search for.

This preferred roaming list is provided by the service provider and stored in the mobile communication terminal upon opening. At this time, the list of available roaming systems is sorted in priority order in the preferred roaming list so that the mobile communication terminal can search for the systems in the priority order.

Service providers serving large regions, such as the United States or China, maintain and use home or roaming system status of all regions by region and priority on one preferred roaming list. It is difficult and complicated to do.

Therefore, the system information of a small unit (radius about 10 km) cannot be effectively provided to the mobile communication terminal. In the roaming list, if the regional classification is divided into larger units (states of the United States or provinces of Korea), all mobile terminals in the region search the system using the same roaming list information. This is an inefficient search method that does not reflect the system configuration status.

In this case, a mobile communication terminal in a roaming list in a specific area is actually far away from the local area, so that it is a waste of time by searching for an unobtainable system before an existing system.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. In the mobile communication terminal operating in different regions, the mobile communication terminal searches for a wireless channel to perform a roaming service. It is an object of the present invention to provide a roaming service method, a mobile communication terminal, and a mobile communication system of a mobile communication terminal that preferentially search for roaming serviceable neighbor systems in a corresponding region without performing a search.

According to an aspect of the present invention, a mobile communication terminal includes a memory and a controller. In the memory, a preferred roaming list (PRL) including at least one home system and a roaming system is stored.

The control unit scans the base station of the home system through the base station scan. The control unit receives a list of neighboring roaming systems in the region from the scanned base station, and selects roaming systems in the list of neighboring systems from the preferred roaming list. Then, when the roaming service is requested, the controller sequentially scans only base stations of the selected roaming system.

When a roaming service is requested, the control unit must sequentially scan roaming systems for roaming in the preferred roaming list and select an optimal roaming system. In this case, all roaming systems in the preferred roaming list are sequentially scanned. Instead, the scanning procedure of the roaming system can be significantly simplified by sequentially scanning only roaming systems that are selected by the list of neighboring systems received from the base station and roamable in the corresponding area.

Preferably, the memory may comprise a nonvolatile memory for storing a preferred roaming list and a volatile memory for storing a list of neighboring systems.

In a roaming service method of a mobile communication terminal according to another aspect of the present invention, a step of storing a preferred roaming list (PRL) including at least one home system and a roaming system is performed.

Scanning the base station of the home system by the preferred roaming list while the preferred roaming list is stored, and receiving and storing a list of neighboring roaming systems in the region from the scanned base station.

When a list of neighboring systems is received, a step of selecting roaming systems in the list of neighboring systems from the preferred roaming list is performed.

When roaming services are requested while roaming systems are selected, only the base stations of the selected roaming systems are sequentially scanned.

Here, receiving and storing the neighboring system list may include receiving a list of neighboring systems broadcast from the scanned base station, comparing the list of the received neighboring systems with a list of previously stored neighboring systems, and comparing the list of neighboring systems. And updating the list of neighboring systems with the latest information.

A mobile communication system according to another aspect of the present invention includes a base station and a mobile communication terminal. The base station periodically broadcasts a list of roaming neighboring systems in the region to the mobile communication terminal in the region.

The mobile terminal stores a preferred roaming list (PRL) composed of at least one home system and a roaming system, and the base station scans a list of neighboring roaming systems in the region from the base station of the scanned home system through a base station scan. Upon reception, the roaming systems in the neighboring system list are selected from the preferred roaming list, and only roaming base stations of the selected roaming system are sequentially scanned when roaming service is requested.

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

1 is a block diagram of a mobile communication system according to an embodiment of the present invention.

1, a mobile communication system according to an embodiment of the present invention includes a base station 10 of a home system broadcasting a list of roamable systems, and a mobile communication operator operating a base station 10 of a home system. Receives and stores a list of base stations 20, 30, 40, 50 of other mobile communication providers with roaming service agreements, and neighboring systems broadcasted from the base station 10 of the home system scanned through the base station scan. And a mobile communication terminal 100 for scanning the roaming system 20 for roaming based on the list of neighboring systems.

The base stations 20, 30, 40, and 50 of the other mobile communication service providers that have a roaming service contract with the mobile communication service provider operating the base station of the home system become neighboring systems in terms of the base station 10 of the home system.

Here, the neighboring system refers to base stations 20, 30, 40, and 50 of other mobile communication providers that have a roaming service contract with a mobile communication operator operating a base station of a home system. It is assumed that base stations of home systems operated by the same communication service provider are not included.

Also, in the drawing, the mobile communication terminal 100 receives roaming by receiving a neighbor system list from the home system base station 10 to facilitate explanation, but the base station of the home system performs a handoff in a corresponding region. Many are provided for this purpose.

The base station 10 has a list of systems 20, 30, 40, and 50 of roaming service providers with roaming service contracts in the area. This list is called a neighbor system list. The neighbor system list is a list of systems operated by other mobile communication providers that have a roaming service contract in each region where the base station is located.

Therefore, the neighbor system list of each base station is different depending on the region where the base station is located.

The neighbor system list includes various system identifiers of neighboring systems for which roaming service contracts are concluded in the region where the corresponding base station is located. That is, it includes information on the system that is operated by another mobile operator that has a roaming service contract.

Therefore, the neighbor system list (Neighbor System list) is a neighbor list message (NLM: Neighbor List Message) broadcast by the base station to provide the base station information to the mobile communication terminal, the General Neighbor List Message (GNLM), It is distinguished from an Extended Neighbor List Message (ENLM), a System Parameter Message (SPM), and an Extended System Parameter Message (ESPM).

The neighbor list message is information for a neighbor base station operated by the same mobile operator and is information for performing handoff.

The General Neighbor List Message (GNLM) and the Extended Neighbor List Message (ENLM) are information for handoff similarly to the Neighbor List Message (NLM).

The system identifier included in the neighbor system list may include frequency channel information, geography information, priority, communication system identifier (SID) information of the service provider, network identifier (NID), and the like. In the simplest case, this can be done with frequency channel information alone.

Each base station periodically broadcasts its neighbor system list from the mobile communication terminal 100 in the corresponding area.

Here, each base station may broadcast a neighbor system list in a separate message form, or may be broadcast in addition to a predefined message for broadcasting information of each base station. . The predefined message means a message that is broadcast among forward messages defined by the mobile communication standard, and a detailed description thereof will be omitted.

The mobile communication terminal 100 has a preferred roaming list (PRL). The preferred roaming list stores system information of a home system and a roaming system necessary for accessing a wireless network in the mobile communication terminal 100.

When the mobile communication terminal 100 is initially activated and wants to access a wireless network system, the mobile communication terminal 100 selects a base station of a home system to be read and scanned by a PRL.

When the base station to be scanned is selected, the mobile communication terminal 100 scans the base station using the radio frequency of the base station in the PRL, and receives the information of the base station broadcast from the base station through the radio frequency. Perform location registration with the base station.

After performing location registration, the mobile communication terminal 100 receives a list of neighboring roaming systems from a corresponding base station. The list of neighboring systems is information broadcast from each base station and consists of a list of neighboring systems roaming serviceable in a corresponding area.

The mobile communication terminal 100 selects neighboring systems in the list of neighboring systems stored in the RAM 113 in the PRL it has.

Subsequently, the mobile communication terminal 100 communicates with the base station, and when the received power from the base station is lowered below the threshold or the mobile communication terminal is located in the no service area, the mobile communication terminal 100 moves from the home system to the roaming system. Follow the procedure for roaming.

The mobile communication terminal 100 performs a procedure of sequentially scanning a roaming system capable of a mobile communication service based on a list of roaming systems in the PRL by reading a PRL which has a roaming service. .

In this case, the mobile communication terminal 100 sequentially scans only roaming systems selected by a list of neighboring systems.

As the mobile communication terminal 100 sequentially scans roaming systems selected by a list of neighboring systems among roaming systems in the PRL, the roaming system capable of roaming service in a corresponding region is first scanned.

The mobile communication terminal 100 scans the base station of the roaming system using the radio frequency of the roaming system having the highest priority among the roaming systems selected by the list of neighboring systems among the roaming systems in the PRL.

Subsequently, when base station information of the base station is received through the radio frequency of the roaming system, location registration is performed with the base station and a roaming service procedure is performed.

2 is a block diagram of a mobile communication terminal for explaining performing a roaming service in a mobile communication terminal according to an embodiment of the present invention.

Referring to FIG. 2, the mobile communication terminal 100 according to an embodiment of the present invention uses a memory 110 that stores various information for a roaming service including a PRL and a system identifier defined in the PRL. A control unit 120 for performing a wireless network system connection, an RF unit 130 for transmitting a wireless network system connection message generated by the control unit 120 to a wireless network through wireless communication, a voice processing unit 140, The speaker 150, the microphone 160, a key input unit 170 formed of a button, and a display unit 180 providing a screen window are configured.

The mobile communication terminal 100 stores data for performing initial startup of the mobile communication terminal 100 and corresponding software programs for performing various multimedia services in the memory 110.

Data for performing initial startup of the mobile communication terminal 100 are stored in the ROM 111, and operating system (OS) call processing software requiring real time processing and software programs for performing various multimedia services are generally mobile. It is stored in the flash memory 112 of the communication terminal 100. The variables and states of these programs are loaded into RAM 113 and the corresponding operations are performed.

Data stored in the flash memory 112 may be downloaded and installed or additionally updated by the corresponding software program through wired or wireless Internet or wired network.

In addition, the mobile communication terminal 100 stores the PRL for accessing the system of the wireless network in the ROM 111 or the flash memory 112. The PRL is a list that stores system identifier information allocated to each service provider and includes information about a home system and a roaming system.

The information of the home system consists of system information of all home systems operated by the mobile communication service provider in which the corresponding mobile communication terminal 100 is registered.

The roaming system information consists of information of the roaming system operated by another mobile communication service provider that has a roaming service contract with the mobile communication service provider.

The PRL may be stored and released in the ROM 111 or the flash memory 112 at the time of manufacture of the mobile communication terminal 100, downloaded and stored in the flash memory 112 via wired or wireless Internet or a wired network, or further updated. It can also be. At this time, the PRL first stored in the ROM 111 is called a default PRL.

In the PRL stored in the flash memory 112, frequency channel information, geography information, priority, communication system identifier (SID) information of a carrier, and whether the mobile communication terminal uses system identifier information designated when the PRL is used. Contains information specifying (Preferred only).

Here, if the Preferred only field is set to True, it means that only the system specified in the PRL is acquired. If it is set to FALSE, it means that it is obtainable if it is not a negative system.

System identifier (SID) information is allocated for each carrier and does not overlap. For example, a system identifier (SID) of 0 indicates a system of all service providers, and a system identifier (SID) of a specific value indicates a system used by the service provider. For each setting field and setting value of the PRL, refer to the Internet site http://www.ifast.org.

On the other hand, the mobile communication terminal 100 is to use the default PRL stored in the ROM 111 when the PRL stored in the flash memory 112 cannot be used. The default PRL stored in the ROM 111 is hard coded at the time of manufacture of the ROM 111. After the product release of the mobile communication terminal 100, the user may download and update the wired / wireless Internet or wired network. It is not possible.

Here, the default PRL coded in the ROM 111 may include frequency channel information, location information, priority, system identifier information of a designated carrier, and a mobile communication terminal so as to access a wireless network system using a system identifier of a specific operator. Contains information specifying to use only the system identifier information specified when using the default PRL.

When the controller 120 is initially started and wants to access the wireless network system, the controller 120 selects the base station of the home system to be scanned by reading the PRL stored in the flash memory 112.

In general, as the scan priority is selected in the PRL, a base station of a high priority home system is selected as a scan target.

When the base station to be scanned is selected, the controller 120 performs a scan for the base station using the radio frequency of the base station in the PRL.

When the controller 120 receives information of the base station broadcast from the base station through the corresponding radio frequency, the controller 120 performs location registration with the base station.

After performing location registration, the controller 120 receives a list of neighboring roaming systems in the corresponding area from the corresponding base station.

The list of neighboring systems is information broadcast from each base station and consists of a list of neighboring systems roaming serviceable in a corresponding area.

The controller 120 stores a list of neighboring systems received from the base station in the RAM 113 which is a volatile memory.

The list of neighbor systems may be updated at any time as stored in the RAM 113, which is a volatile memory, and the list of neighbor systems stored in the RAM 113 is also erased when the power of the mobile communication terminal is cut off.

The controller 120 selects neighbor systems in the list of neighbor systems stored in the RAM 113 from the PRL stored in the flash memory 112.

Subsequently, the controller 120 communicates with the base station, and when the received power from the base station becomes lower than the threshold or the mobile terminal is located in the no service area, roaming from the home system to the roaming system is performed. Perform the procedure to carry out.

In order to perform a roaming service, the controller 120 reads a PRL stored in the flash memory 112 and sequentially scans a roaming system capable of a mobile communication service based on a list of roaming systems in the PRL. Will be performed.

In this case, the control unit 120 does not scan all roaming systems in sequence for the PRL stored in the flash memory 112, but only scans roaming systems selected by a list of neighboring systems.

The controller 120 sequentially scans roaming systems selected by a list of neighboring systems among roaming systems in the PRL, and then scans roaming systems capable of roaming services in a corresponding region. As a result, the time required to find the optimal roaming system is significantly reduced.

The RF unit 130 is controlled by the controller 120 and converts a signal output from the controller 120 into a wireless signal. In addition, the RF unit 130 converts the radio signal received through the antenna into a desired signal and outputs it.

The voice processing unit 140 modulates the voice signal input from the microphone 160 and converts the voice signal into voice data, and converts the voice data input from the RF unit 130 and voice data stored in the memory 110 into voice signals. The demodulator outputs the voice through the speaker 150.

The key input unit 170 includes a plurality of numeric keys, menu keys, and function keys for performing various functions, and outputs key data to the control unit 120 by an external operation.

Accordingly, the controller 120 reads the menu from the memory 110 and displays the menu on the display unit 180 according to a user's menu display request by the key input unit 170. That is, the key input unit 170 is a conventional user information input means, and has a plurality of keys suitable for a mobile communication terminal to be applied, such as a plurality of numeric keys and function keys, and if there is an input of each of the provided keys, Therefore, by outputting the corresponding unique key data to the control unit 120, through the key input operation of the key input unit 170 to enter the menu display mode and selection of the menu is made. Then, the controller 120 reads a menu according to the corresponding key input from the memory 110 and displays the menu on the display unit 180.

The display unit 180 is a display device such as a liquid crystal display (LCD). The display unit 180 displays a state of a mobile communication terminal or a progress of a program under the control of the controller 120. That is, the overall state of the mobile communication terminal and input user information are displayed.

3 and 4 are flowcharts of performing a roaming service in a mobile communication terminal according to an embodiment of the present invention.

3 and 4, the controller 120 of the mobile communication terminal 100 reads data to the RAM 113 for initial startup of the mobile communication terminal 100 from the ROM 111 when power is supplied. Perform a boot (S1). As booting is performed, screen information of the mobile communication terminal is displayed on the display unit 180.

After booting for initial startup is performed, the controller 120 reads the PRL stored in the flash memory 112 and scans the base station of each home system by priority according to the priority entry of the home system specified in the PRL ( S2).

The control unit 120 scans the base station of the home system through the RF unit 130 using the radio frequency of the home system having the highest priority among the list of home systems in the PRL.

When the controller 120 receives the information of the base station broadcast from the base station through the radio frequency by the RF unit 130, the controller 120 registers a location with the base station (S3).

Since the mobile communication terminal performs the location registration procedure with the base station using a known technique, a detailed description thereof will be omitted.

After performing location registration, the control unit 120 receives a list of neighboring systems roamable in the corresponding area from the base station through the RF unit 130 (S4).

The controller 120 stores a list of neighboring systems received from the base station through the RF unit 130 in the RAM 113, which is a volatile memory (S5).

The controller 120 selects roaming systems in a list of neighboring systems stored in the RAM 113 from the PRL stored in the flash memory 112 (S6).

Thereafter, the controller 120 periodically performs a base station scan through the RF unit 130 to perform location registration with a base station having the strongest reception power from the base station and perform handoff.

Therefore, the controller 120 determines whether the handoff is performed periodically (S7).

When the controller 120 performs a handoff from one base station to another neighboring base station, the control unit 120 receives a list of neighboring systems broadcasted from the corresponding base station and stores the list of neighboring systems previously stored in its RAM 113 of the new neighboring system. Update to a list (S8).

Accordingly, when the mobile communication terminal moves from one region to another region, the mobile communication terminal can select only a neighboring system capable of roaming service in the region from the PRL stored in the flash memory 112.

Thereafter, the controller 120 determines whether the reception power from the base station is lowered below the threshold when communicating with the base station (S9).

As a result of the determination, when the reception power from the base station is lowered below the threshold, it is determined whether or not it is located in the no service area (S10).

Here, whether the base station is located in the no service area is determined based on whether a base station capable of performing a mobile communication service is scanned even though the base stations of the home system in the PRL are sequentially scanned. If the base stations of the home system in the PRL are sequentially scanned but there are no base stations of the serviceable home system, it is determined that they are in the no service area.

If it is determined that the corresponding mobile communication terminal is not located in the no service area, the controller 120 performs handoff (S11).

The controller 120 performs a procedure for roaming from the home system to the roaming system when the determined mobile communication terminal is located in the no service area. When the roaming service is performed, the controller 120 may display a message indicating that the roaming service is being performed on the display unit 180 as screen information.

The control unit 120 uses the radio frequency of the roaming system having the highest priority among the roaming systems selected from the list of neighboring systems among the PRLs stored in the flash memory 112 to perform the roaming service. Scan (S12).

In operation S13, it is determined whether information of the base station broadcast from the base station of the roaming system is received through the corresponding radio frequency.

As a result of the determination, when base station information is received from the base station of the roaming system, a procedure for roaming service is performed by performing location registration with the base station (S14).

If it is determined that base station information is not received from the base station of the roaming system, the radio frequency of the roaming system corresponding to the next priority among the roaming systems selected by the list of neighboring systems among the PRLs stored in the flash memory 112 is used. To perform a procedure for scanning the base station of the roaming system (S15).

The present invention has been described with reference to preferred embodiments and many specific variations. However, those skilled in the art will understand that many other embodiments other than those specifically described also fall within the spirit and scope of the invention.

According to the present invention, the base station periodically broadcasts a list of neighboring systems capable of roaming service in the region to each mobile communication terminal in the region.

The mobile communication terminal receives a list of neighboring systems broadcast from the base station and selects only roaming systems capable of roaming service in the region from the PRL stored in its memory by the list of the neighboring systems.

When searching for a wireless channel to perform a roaming service, the mobile terminal searches only the roaming systems selected from the PRL in turn, and thus, among the roaming systems in the PRL, the roaming service capable of roaming service in the region can be first scanned. By doing so, the time taken to scan the roaming system to perform roaming can be shortened, and the success rate of the roaming system scan can be increased.

Claims (5)

A memory for storing a preferred roaming list (PRL) comprising at least one home system and a roaming system; Receiving a list of roaming neighboring systems in the region from the base station of the home system scanned through the base station scan to screen the roaming systems in the list of the received neighboring systems in the preferred roaming list, and when the roaming service is requested And a control unit that sequentially scans only base stations of the selected roaming system. The method of claim 1, wherein the memory, A nonvolatile memory for storing the preferred roaming list; And a volatile memory for storing a list of the neighboring systems. Storing a preferred roaming list (PRL) comprising at least one home system and a roaming system; Scanning a base station of the home system and receiving and storing a list of roaming neighboring systems in the region from the scanned base station; Selecting roaming systems in the received list of neighboring systems in the preferred roaming list; And roaming sequentially scanning only base stations of the selected roaming system in the preferred roaming list when a roaming service is requested. The method according to claim 3, Receiving and storing the neighbor system list, Receiving a list of neighboring systems broadcast from the scanned base station; And comparing the received neighbor system list with a list of previously stored neighbor systems and updating the list of neighboring systems with the latest information according to the comparison result. A base station broadcasting a list of roaming neighboring systems in the region; Preferred Roaming List (PRL), which consists of at least one home system and roaming system, is stored, and a list of neighboring roaming systems in a corresponding region is received from a base station of a scanned home system through a base station scan. And a mobile communication terminal that selects roaming systems in the received list of neighboring systems from a preferred roaming list, and sequentially scans only base stations of the selected roaming systems when roaming service is requested.

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