WO2008069509A1

WO2008069509A1 - Apparatus and method for automatically switching dmb channel in dmb multiple frequency network

Info

Publication number: WO2008069509A1
Application number: PCT/KR2007/006160
Authority: WO
Inventors: Youngho Jeong; Hyungon Kim; Chung-Hyun Ahn; Soo-In Lee
Original assignee: Electronics And Telecommunications Research Institute
Priority date: 2006-12-05
Filing date: 2007-11-30
Publication date: 2008-06-12

Abstract

Provided are an apparatus and method for switching a DMB channel in a DMB multiple frequency network. The apparatus includes a handoff sensing unit for sensing a handoff operation between mobile communication base stations, which is performed according to movement of a DMB terminal, and a channel switching unit for determining necessity of switching a DMB channel when the handoff operation is sensed by the handoff sensing unit and a new mobile communication base station coverage is entered.

Description

APPARATUS AND METHOD FOR AUTOMATICALLY

SWITCHING DMB CHANNEL IN DMB MULTIPLE

FREQUENCY NETWORK

Technical Field

[1] The present invention relates to an apparatus and method for automatically switching a digital multimedia broadcasting (DMB) channel in a DMB multiple frequency network; and, more particularly, to a DMB channel switching apparatus and method for determining whether to switch a DMB channel and switching a DMB channel according to the determination result in a DMB multiple frequency network whenever handoff operation is performed between mobile communication base stations according to the movement of a DMB terminal having a mobile communication module.

[2] This work was supported by IT R & D program of MIC/ IITA [2005-S-403-02, "Development of Super-intelligent Multimedia Anytime- anywhere Realistic TV (SmarTV) Technology"]. Background Art

[3] Fig. 1 is a diagram illustrating a method for manually switching a DMB channel in a

DMB multiple frequency network according to the related art.

[4] In digital multimedia broadcasting (DMB) such as terrestrial digital multimedia broadcasting (T-DMB), digital video broadcasting-handheld (DVB-H), Forward Link Only (FLO), Integrated Services Digital Broadcasting-Terrestrial (ISDB-T), DMB services are provided through a multiple frequency network (MFN). In the MFN, an entire DMB service area divided into a plurality of cells, and each of the divided cells is allocated with a unique DMB channel.

[5] In order to constantly provide seamless DMB services to users although the users with a DMB terminal travels from one cell to the other cell in the DMB multiple frequency network, it was required to perform a DMB channel switch operation to change a DMB channel of one cell to that of the other cell.

[6] That is, Fig. 1 shows one of manual DMB channel switching methods according to the related art. As shown in Fig. 1, a DMB service area includes a plurality of cells, such as a first cell 101 and a second cell 102. Each cell denotes a coverage area of one DMB channel. The first cell 101 is allocated with a first DMB channel, and the second cell 102 is allocated with a second DMB channel.

[7] When a user having a DMB terminal 10 moves from the first cell 101 to the second cell 102, the receiving power of the first DMB channel 1 (ch#l) becomes decreased. That is, the receipt state of the first DMB channel 1 deteriorates. In the DMB channel switch method according to the related art, the user needed to recognize the deterioration of the receipt state of the first DMB channel 1 and manually switches the first DMB channel to the second DMB channel. That is, if a receipt state of a DMB channel deteriorates because a user moves into a new DMB channel coverage area, the user must manually change a DMB channel to that allocated to the entered new DMB channel coverage area according to the related art.

[8] As described above, the DMB channel change method according to the related art was inconvenient to a user because the user must manually perform the channel switch operation based on the receipt state of a current DMB channel whenever the user moves to a new DMB channel coverage area. Also, a related service was not smoothly provided to a user when a DMB channel is switched. Disclosure of Invention Technical Problem

[9] An embodiment of the present invention is directed to providing an apparatus and method for automatically switching a DMB channel in a DMB multiple frequency network.

[10] Other objects and advantages of the present invention can be understood by the following description, and become apparent with reference to the embodiments of the present invention. Also, it is obvious to those skilled in the art of the present invention that the objects and advantages of the present invention can be realized by the means as claimed and combinations thereof. Technical Solution

[11] In accordance with an aspect of the present invention, there is provided an apparatus for switching a digital multimedia broadcasting (DMB) channel in a DMB multiple frequency network, the apparatus including: a handoff sensing unit for sensing a handoff operation between mobile communication base stations, which is performed according to movement of a DMB receiving terminal; and a channel switching unit for determining necessity of switching a DMB channel when the handoff operation is sensed by the handoff sensing unit and a new mobile communication base station coverage is entered.

[12] In accordance with another aspect of the present invention, there is provided a method for switching a digital multimedia broadcasting (DMB) channel in a DMB multiple frequency network, the method including the steps of: a) sensing a handoff operation between mobile communication base stations, which is performed according to movement of a DMB receiving terminal; and b) determining necessity of switching a DMB channel whenever the handoff operation is sensed and a new mobile commu- nication base station coverage is entered.

Advantageous Effects

[13] A DMB channel switching apparatus and method according to the present invention can automatically switch a DMB channel using a handoff algorithm for mobile communication such as CDMA, GSM, and WiBro when a bidirectional DMB terminal moves from a current DMB channel coverage area to an adjacent DMB channel coverage area in a multiple frequency network (MFN).

[14] That is, the DMB channel switching apparatus according to the present invention automatically switches a DMB channel without the participation of a user. Also, a DMB service can be provided to a user seamlessly by automatically switching the DMB channel.

[15] Furthermore, the DMB channel switching apparatus and method according to the present invention do not perform a large amount of calculations for automatically switching a DMB channel in a DMB multiple frequency network environment because of using a result of performing a handoff operation in typical mobile communication systems such as CDMA, GSM, and WiBro systems. Therefore, the DMB channel switching apparatus and method according to the present invention are excellent in power efficiency. The excellent power efficiency is a valuable advantage for portable devices that have a limited power source. The automatic channel switching function can be realized with minimum modification of a typical DMB terminal. That is, the apparatus and method for switching a DMB channel in a DMB multiple frequency network according to the present invention can conveniently embody an automatic channel switching function at low costs in a typical DMB receiving terminal. Brief Description of the Drawings

[16] Fig. 1 is a diagram illustrating a method for manually switching a DMB channel in a

DMB multiple frequency network according to the related art.

[17] Fig. 2 is a diagram illustrating a method for automatically switching a DMB channel in a DMB multiple frequency network in accordance with an embodiment of the present invention.

[18] Fig. 3 is a flowchart illustrating a method for automatically switching a DMB channel in a DMB multiple frequency network in accordance with an embodiment of the present invention.

[19] Fig. 4 is a diagram illustrating a DMB terminal for automatically switching a DMB channel in a DMB multiple frequency network in accordance with an embodiment of the present invention.

[20] Fig. 5 is a block diagram illustrating an apparatus for automatically switching a DMB channel in accordance with an embodiment of the present invention. [21] Fig. 6 illustrates a DMB channel allocation table for a CDMA base station in accordance with an embodiment of the present invention.

[22] Fig. 7 is a diagram illustrating a service ID switch table per a DMB channel in accordance with an embodiment of the present invention. Mode for the Invention

[23] At first, an apparatus and method for switching a DMB channel in a DMB multiple frequency network according to an embodiment of the present invention will be briefly described.

[24] In the present embodiment, T-DMB, DVB-H, FLO, ISDB-T based DMB terminals with a mobile communication module use a handoff algorithm provided from CDMA, GSM, WiBro mobile communication systems to recognize that a DMB terminal moves into a new adjacent DMB channel coverage area. Also, the apparatus and method for switching a DMB channel according to an embodiment of the present invention is for DMB, which provides a related service through a multiple frequency network (MFN), with a bidirectional communication mode using CDMA, GSM, and WiBro as a return channel.

[25] That is, the apparatus and method for switching a DMB channel according to an embodiment of the present invention enables a DMB terminal having one of CDMA, GSM, and WiBro communication modules to have information about a target base station for handoff when the DMB terminal decides to perform a handoff operation and to determine whether the target base station is in a new DMB channel coverage area based on the information about the target base station.

[26] A DMB terminal cannot determine whether or not the DMB terminal enters to a new

DMB channel coverage area only with base station information. The DMB terminal must have information about DMB channels of each base station. If the DMB terminal needs to switch a DMB channel because the DMB terminal determines that the DMB terminal moves to a new coverage area, the DMB terminal switches a current channel to a corresponding DMB channel of a new coverage area and automatically switches a service that a user previously receives through the DMB channel of the previous DMB channel coverage area to the same service provided through the changed DMB channel of the new coverage area.

[27] The present invention relates to automatic channel switch in T-DMB, DVB-H, FLO, and ISDB-T based DMB terminals with mobile communication module. Particularly, the present invention relates to a mechanism for automatically switching a current DMB channel to another DMB channel using a mobile communication handoff algorithm such as CDMA, GSM, or WiBro handoff algorithm when a DMB terminal moves to an adjacent coverage area in a multiple frequency network environment. [28] That is, the apparatus and method for switching a DMB channel in a DMB multiple frequency network according to an embodiment of the present invention enables a DMB terminal to detect a new DMB channel coverage area when a DMB terminal moves to the new DMB channel coverage area, determine whether to change a channel in a terminal level, and change a DMB channel to a new channel based on the determination result.

[29] Furthermore, the apparatus and method for switching a DMB channel in a DMB multiple frequency network according to an embodiment of the present invention enables a user to reselect a predetermined service that the user was receiving through a DMB channel of a previous DMB channel coverage area in order to continuously receive the predetermined service, such as a video service, an audio service, or a data service.

[30] The advantages, features and aspects of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, which is set forth hereinafter. Therefore, those skilled in the field of this art of the present invention can embody the technological concept and scope of the invention easily. In addition, if it is considered that detailed description on a related art may obscure the points of the present invention, the detailed description will not be provided herein. The preferred embodiments of the present invention will be described in detail hereinafter with reference to the attached drawings. Also, the present invention will be described with a code division multiple access (CDMA) system as an example of a mobile communication system.

[31] Fig. 2 is a diagram illustrating a method for automatically switching a DMB channel in a DMB multiple frequency network in accordance with an embodiment of the present invention.

[32] CDMA base stations are deployed according to a cell panning for optimizing the arrangement of base stations. Meanwhile, since digital multimedia broadcasting (DMB) is provided in an environment having an existing analog TV channel, it is difficult to form a single frequency network. Therefore, in the DMB, an entire service area is divided into a plurality of cells which are DMB channel coverage areas and an unique DMB channel is allocated to each DMB channel coverage areas, thereby forming a multiple frequency network (MFN).

[33] In Fig. 2, a CDMA network overlaps with a DMB network. In generally, the DMB channel coverage areas 210 and 220 are wider than the cell coverage areas 211 and 221 of a CDMA base station. That is, a channel coverage area 210 or 220 of a DMB transmitter 21 or 22 includes a plurality of cell coverage areas 211 and 221 of a plurality of CDMA base stations.

[34] In the present embodiment, corresponding DMB channel coverage areas are mapped to CDMA base stations based on the relation between a DMB channel coverage area and a CDMA Cell, and the mapping information is used. A broadcasting coverage area of each DMB channel is previously measured in the coverage of a CDMA base station, and a table is formed with information about the measured broadcasting coverage area. That is, the table, a DMB channel allocation table 201, is formed as shown in Fig. 6, and the DMB channel allocation table 201 is stored in a predetermined server (not shown). Based on the DMB channel allocation table 201, it is possible to determine which a DMB channel coverage area belongings to a predetermined base station. For example, CDMA base stations 1, 2, 3, and 4 belong to a first DMB channel coverage 201, and CDMA base stations 11, 12, 13, and 14 belong to a second DMB channel coverage 220.

[35] A handoff algorithm for a CDMA base station having a return channel is used to recognize that a DMB terminal 20 moves to a new adjacent coverage 220. Handoff between CDMA base stations is a procedure for sustaining the continuation of call by allocating a new channel of a new base station to a terminal when the terminal moves from a current cell coverage area to a new cell coverage area of the new base station. A mobile terminal decides a target base station to handoff using a neighbor cell list and a handoff threshold. The mobile terminal performs a handoff operation to the decided base station. That is, if the intensity of a pilot signal transmitted from a current base station is smaller than that of an adjacent base station according to the movement of the mobile terminal, the mobile terminal selects an adjacent base station to handoff as a target base station according to a predetermined handoff algorithm.

[36] When a mobile terminal receives a request of triggering a handoff operation, the mobile terminal performs a handoff operation through a communication protocol.

[37] In the present embodiment, handoff triggering information and base station information are used to perform the handoff operation because a new base station to handoff is decided when the handoff operation is triggered. The handoff triggering information is used to inform the DMB application software of a DMB terminal that the handoff operation is triggered. The base station information includes information about a target base station to handoff. The base station information is used to determine whether a DMB channel mapped to the target base station is different from a current DMB channel or not.

[38] That is, the DMB application software determines whether a DMB channel coverage area mapped to a base station where a DMB terminal moves into is identical to a previous DMB channel coverage area or not by inquiring of the DMB channel allocation table 201, which is previously stored as shown in Fig. 2. If the DMB channel coverage areas are identical, a DMB channel is not switched. If the DMB channel coverage areas are different, a DMB channel switches to a new DMB channel defined in the DMB channel allocation table.

[39] The operation for switching the DMB channel will be described in more detail with reference to Fig. 2.

[40] When a DMB terminal moves from a coverage area of a third CDMA base station 3, which is the first DMB channel coverage area, to a coverage area of an eleventh CDMA base station 11, a handoff operation is triggered in a CDMA module of a DMB terminal. The DMB application software informed of the handoff triggering inquires of the DMB channel allocation table 201, which is previously stored therein.

[41] Since a newly entering DMB channel coverage area is a second DMB channel coverage 220 which is different from the previous DMB channel coverage area 210 that is the first DMB channel coverage area (#ch 1), the DMB application software switches a DMB channel to the second DMB channel (#ch X).

[42] When the DMB channel switches, service identification (ID) information is required to identify each service if a plurality of services including a video service, an audio service, and a data service, are provided. The service ID information will be described with referent of Fig. 7 in later.

[43] Fig. 3 is a flowchart illustrating a method for automatically switching a DMB channel in a DMB multiple frequency network in accordance with an embodiment of the present invention. That is, Fig. 3 shows an automatic channel switching algorithm installed in DMB application software in a DMB terminal.

[44] The automatic channel switching algorithm according to the present embodiment is triggered and performed once when handoff is generated between CDMA base stations.

[45] At step S300, a DMB terminal operates in an Idle state or a call state in a predetermined CDMA base station. When the DMB terminal moves into an adjacent base station coverage area, handoff between CDMA base stations is performed.

[46] If the CDMA module layer 3 of the DMB terminal decides to perform a handoff operation at step S302, the handoff operation is performed to change a CDMA base station. The CDMA module layer 3 informs DMB application software in an application layer about the triggering of the handoff operation and information about a CDMA base station to handoff at step S304.

[47] After being informed, the DMB application software inquires of the DMB channel allocation table shown in Fig. 6 and the service ID switch table shown in Fig. 7 about adjacent DMB channel information at step S306. The DMB channel allocation table and the service ID switch table may be previously stored in the DMB terminal, or may be received from a predetermined server through requesting.

[48] If it is not necessary to switch a DMB channel, the DMB terminal sustains existing operation states. On the contrary, if it is necessary to switch a DMB channel, the DMB application software switches a current DMB channel to a DMB channel allocated to a new CDMA base station coverage area at step S310.

[49] That is, a DMB channel allocated to a new CDMA base station coverage area is compared with a previous DMB channel. If the DMB channels are identical, it is not necessary to change the DMB channel. If the DMB channels are different and if the existing service is sustained, it is necessary to perform a DMB channel switching operation at step S310. If the DMB channels are identical, it means that the DMB terminal is in the identical DMB channel coverage area. If the DMB channels are different, it means that the DMB terminal enters a different DMB channel coverage area.

[50] The DMB terminal can determine whether the existing service is sustained or not through the service ID switch table. The DMB terminal finally determines the necessity of switching a DMB channel based on the result of confirming the service ID switch table. That is, the DMB terminal obtains service IDs mapped to a predetermined channel and an adjacent channel. If the obtained service IDs include a service ID corresponding to a service that a user previously receives, that is, if an existing service is sustained, the DMB terminal also switches a service ID while switching the DMB channel. If the obtained service IDs do not include a service ID corresponding to the service that a user previously receives, the DMB terminal performs an automatic channel switch operation and switches the existing service to a default service in the switched DMB channel. In another embodiment, if the corresponding service ID is not included, that is, if the existing service is not sustained, the channel switch operation is automatically terminated or the DMB terminal informs of a user or enables a user to select another service.

[51] Fig. 4 is a diagram illustrating a DMB terminal for automatically switching a DMB channel in a DMB multiple frequency network in accordance with an embodiment of the present invention.

[52] As shown in Fig. 4, the DMB terminal includes a low transport layer 40 and an application layer 41. The DMB terminal includes a DMB module 401 and a CDMA module 402 in the low transport layer 40 at the same time in order to support a return channel. The DMB module 401 receives and processes a DMB broadcasting signal, and the CDMA module 402 is one of typical mobile communication modules that performs general mobile communication functions including a handoff operation.

[53] The DMB application software 411 includes DMB channel switch software for performing a function of automatically switching a DMB channel according to the movement of a user in a DMB multiple frequency network. The DMB application software 411 may stores tables for switching a DMB channel, which are shown in Figs. 6 and 7, in an own memory 412. In another embodiment, the DMB application software 411 receives the table from a predetermined server. The tables include a DMB channel allocation table of Fig. 6 and a service ID switch table of Fig. 7.

[54] For example, the DMB application software 411 of Fig. 4 is a functional block for automatically switching a DMB channel, and a memory 412 stores table information used to determine the necessity of switching a DMB channel. Two functional blocks are equivalent to the automatic DMB channel switch apparatus 50.

[55] Hereinafter, a DMB channel switch procedure of a DMB terminal will be described.

The layer 3 403 of the CDMA module 402 performs a handoff operation between CDMA base stations. The layer 3 403 informs the DMB application software 411 about triggering information and target base station information when it is decided to perform a handoff operation. Then, the DMB application software 411 determines whether it is necessary to switch a DMB channel using the DMB channel allocation table and the service ID switch table stored in the memory 412 and switches a DMB channel according to the determination result.

[56] Fig. 5 is a block diagram illustrating an apparatus for automatically switching a DMB channel in accordance with an embodiment of the present invention. That is, Fig. 5 shows detail configuration of DMB application software 411 and a memory 412 in Fig. 4.

[57] An automatic DMB channel switch apparatus 50 according to the present embodiment determines whether it is necessary to switch a DMB channel or not using DMB channel allocation information whenever a handoff operation is performed between communication mobile base stations because a DMB terminal enters a new mobile communication base station and switch a DMB channel according to the determination result. As shown in Fig. 5, the apparatus for automatically switching a DMB channel includes a handoff sensing unit 51, a channel switching unit 52, and a memory 53.

[58] The handoff sensing unit 51 detects a handoff operation performed between CDMA base stations by the CDMA module 402 according to the movement of a user, that is, the movement of a DMB terminal. In more detail, the handoff sensing unit 51 detects the handoff operation by receiving handoff notice and target base station information from the CDMA module of the DMB terminal.

[59] The channel switching unit 52 determines whether to switch a DMB channel using a

DMB channel allocation table and a service ID stored in the memory 53. Based on the determination result, the channel switching unit 52 switches a DMB channel.

[60] Fig. 6 is a diagram illustrating a DMB channel allocation table per a CDMA base station in accordance with an embodiment of the present invention.

[61] In a method for allocating an optimal DMB channel for each CDMA base station according to the present embodiment, a broadcasting coverage area of each DMB channel is measured in each CDMA base station, and a DMB channel having the optimal measuring value is allocated to a corresponding CDMA base station as a DMB channel.

[62] As described above, the table shown in Fig. 6 stores the optimal DMB channels allocated to each of CDMA base stations. The DMB channel allocation table is a table showing mapping relations between CDMA base station coverages and DMB channel coverages.

[63] The DMB channel allocation table may be previously generated and stored in an internal memory of a DMB terminal. In another embodiment, the DMB channel allocation table may be stored in a predetermined server on a network. In this case, a DMB terminal may dynamically receives a DMB channel allocation table according to the request of a DMB terminal.

[64] As shown in Fig. 6, the same 8^th DMB channel is allocated to the first CDMA base station and the second CDMA base station. It means that the first and second CDMA base stations are included in the same DMB channel coverage area.

[65] Since the same 10^th DMB channel is allocated to the third and fourth CDMA base stations, the third and fourth CDMA base stations are included in the same DMB channel coverage area.

[66] Fig. 7 is a service ID switch table per a DMB channel in accordance with an embodiment of the present invention.

[67] Since a plurality of services such as an audio service, a video service, and a data service are provided through one DMB channel, an identifier is required to identify a plurality of services in order to sustain the same service before/after switching a DMB channel. Therefore, a service ID is used in the present embodiment.

[68] When a DMB channel is automatically switched according to the present embodiment, it is required to select the same service that a user used in a previous DMB channel at the same time of selecting an adjacent DMB channel. That is, since service IDs may be the same or different according to each of DMB channels, a service ID switch table is required to sustain the same service. The service ID switch table is information about services of each channel. The service ID switch tale is provided to enable a user to receive the same service before/after switching a DMB channel. That is, the service ID switch table shows service ID corresponding relation to provide the same service between a current DMB channel and an adjacent DMB channel.

[69] Referring to Fig. 7, when a DMB terminal receiving a service having a service ID #2 through a current 8^th DMB channel switches the current 8^th DMB channel to an adjacent 10^th DMB channel, the DMB terminal must select a service ID #3 of the 10^th DMB channel to sustain the same service.

[70] As described above, the service ID switch table is previously stored in a memory of a DMB terminal like the DMB channel allocation table. In another embodiment, the service ID switch table may be stored in a predetermined external server on a network. In this case, the service ID switch table may be provided to a DMB terminal according to the request of the DMB terminal.

[71] The above described method according to the present invention can be embodied as a program and stored on a computer readable recording medium. The computer readable recording medium is any data storage device that can store data which can be thereafter read by the computer system. The computer readable recording medium includes a read-only memory (ROM), a random-access memory (RAM), a CD-ROM, a floppy disk, a hard disk and an optical magnetic disk.

[72] The present application contains subject matter related to Korean Patent Application

Nos. 2006-0122472 and 2006-067225, filed in the Korean Intellectual Property Office on December 5, 2006, July 4, 2007, the entire contents of which are incorporated herein by reference.

[73] While the present invention has been described with respect to certain preferred embodiments, it will be apparent to those skilled in the art that various switches and modifications may be made without departing from the spirits and scope of the invention as defined in the following claims.

Claims

[1] An apparatus for switching a digital multimedia broadcasting (DMB) channel in a DMB multiple frequency network, comprising: a handoff sensing means for sensing a handoff operation between mobile communication base stations, which is performed according to movement of a DMB terminal; and a channel switching means for determining necessity of switching a DMB channel when the handoff operation is sensed by the handoff sensing means and a new mobile communication base station coverage is entered.

[2] The apparatus of claim 1, wherein the handoff sensing means senses the handoff operation by receiving information about handoff notice and information about a target base station for handoff from a mobile communication module of the DMB terminal.

[3] The apparatus of claim 1, wherein the channel switching means compares a

DMB channel allocated to a current mobile communication base station and a DMB channel allocated to a target mobile communication base station through DMB channel allocation information including information about DMB channels allocated to each mobile communication base station.

[4] The apparatus of claim 3, wherein the DMB channel allocation information is a

DMB channel allocation table formed of DMB channels which are allocated to each mobile communication base station by measuring broadcasting coverages of DMB channels for each mobile communication base station, selecting one having an optimal measuring value from the DMB channels for each mobile communication base station, and allocating the selected DMB channel having the optimal measuring value to each mobile communication base station.

[5] The apparatus of claim 3, wherein the DMB channel allocation information is stored in a storing means of the DMB terminal or is stored in an external server and provided to the DMB terminal.

[6] The apparatus of claim 3, wherein the channel switching means further performs a function of switching service identification (ID) information using service information including information about services of each channel so as to constantly provide the same service before and after switching a channel in case of DMB broadcasting that provides a plurality of services through one DMB channel.

[7] The apparatus of claim 6, wherein the service information is a service ID switch table that shows relations service ID information corresponding to DMB channels for providing the same service between a current DMB channel and an adjacent DMB channel.

[8] The apparatus of claim 6, wherein the service information is stored in an internal storing means of the DMB terminal or is stored in an external service and provided to the DMB terminal.

[9] The apparatus of claim 7, wherein if the service ID switch table does not include service ID information corresponding to the same service, the channel switching means provides a predetermined service or informs a user and enables the user to select another service.

[10] A method for switching a digital multimedia broadcasting (DMB) channel in a

DMB multiple frequency network, comprising the steps of: a) sensing a handoff operation between mobile communication base stations, which is performed according to movement of a DMB terminal; and b) determining necessity of switching a DMB channel whenever the handoff operation is sensed and a new mobile communication base station coverage is entered.

[11] The method of claim 10, wherein in the a), the handoff operation is sensed by receiving information about handoff notice and information about a target base station for handoff from a mobile communication module of the DMB terminal.

[12] The method of claim 10, wherein the step b) includes the steps of: b-1) comparing a DMB channel allocated to a current mobile communication base station and a DMB channel allocated to a target mobile communication base station through DMB channel allocation information including information about DMB channels allocated to each mobile communication base station; and b-2) switching a DMB channel to the DMB channel of the target mobile communication base station if the DMB channel allocated to a current mobile communication base station is different from the DMB channel allocated to a target mobile communication base station.

[13] The method of claim 12, wherein the DMB channel allocation information is stored in an storing means of the DMB terminal or is stored in an external server and provided to the DMB terminal.

[14] The method of claim 12, further comprising switching service identification (ID) information using information about services of each channel so as to constantly provide the same service before and after switching a channel in case of DMB broadcasting that provides a plurality of services through a DMB channel.

[15] The method of claim 14, wherein the service information is stored in a storing means of the DMB terminal and is stored in an external server and provided to the DMB terminal.