KR102067008B1 - Method and apparatus for transmitting and receiving digital multimedia broadcast and system for transmitting and receiving digital multimedia broadcast - Google Patents

Abstract

The digital multimedia broadcasting (DMB) transmission method by the base station of the present invention includes at least one emergency information signal, the emergency information signal including at least one of an emergency signal and additional information, and the at least one emergency information. Generating an emergency information alarm signal informing of occurrence of a signal, generating at least one emergency information spread signal and an alarm spread signal by assigning different spreading codes to the at least one emergency information signal and the emergency information alarm signal; And transmitting the at least one emergency information spread signal and the alarm spread signal through a transmission frame.

Description

TECHNICAL AND APPARATUS FOR TRANSMITTING AND RECEIVING DIGITAL MULTIMEDIA BROADCAST AND SYSTEM FOR TRANSMITTING AND RECEIVING DIGITAL MULTIMEDIA BROADCAST}

The present invention relates to digital multimedia broadcasting, and more particularly, to an apparatus and method for transmitting and receiving digital multimedia broadcasting, and a system for transmitting and receiving.

In the disaster broadcasting technology through the digital multimedia broadcasting system, when the power plug is plugged in, an additional device may be attached to automatically receive the disaster broadcasting when the disaster broadcasting starts even when the power switch is turned off. Can be. In this way, receiving a disaster broadcast when the power switch is turned off is also called a receiver.

However, in the case of disaster broadcasting through a portable small broadcasting terminal, the power consumption problem is an important problem that can never be overlooked. However, when transmitting a signal related to whether there is a disaster broadcast at a null position of a transmission frame, at least two frames or more processing are required to recognize a disaster. Thus, a need exists for a method that can reduce power consumption by performing less processing.

For this purpose, there is disclosed a disaster broadcasting service system configured to transmit and receive an emergency information presence signal and information on an emergency situation informing an emergency situation, and to provide another service in the same band when the emergency situation is not available (Korean public disclosure). Patent 10-2012-0032403). However, in the conventional disaster broadcasting service system, if one or more services are to be transmitted in an area of providing emergency information or other services, a multiplexing service should be used. In this case, since a plurality of emergency service signals use one channel coding and interleaving spreading code, all services have the same service area and reception quality, and there is a problem in that individual service reception delays occur according to multiple services.

An object of the present invention for solving the above problems is to transmit at least one emergency information-related service using a spreading code set having good self and cross-correlation characteristics to use channel coding, interleaving and spreading codes according to the purpose of the service, respectively. The present invention provides a digital multimedia broadcasting transmitting apparatus and method, a receiving apparatus and method, and a transmitting / receiving system.

Another object of the present invention is to provide a digital multimedia broadcasting transmitting apparatus and method, a receiving apparatus and method, and a transmitting / receiving system, which enable fast service reception at a receiver by designating a spreading code according to each service and transmitting the spreading code according to each service. will be.

Digital Multimedia Broadcast (DMB) transmission method by a base station of the present invention for achieving the above object is at least one emergency information signal-the emergency information signal includes at least one of an emergency signal and additional information- And generating an emergency information alarm signal informing of occurrence of the at least one emergency information signal, and assigning different spreading codes to the at least one emergency information signal and the emergency information alarm signal to at least one emergency information spread signal and an alarm. Generating a spread signal and transmitting the at least one emergency information spread signal and the alarm spread signal through a transmission frame.

The digital multimedia broadcasting transmission method may include generating transmission header information including the configuration and transmission information of the at least emergency information signal and spreading the at least one emergency information signal and the emergency information alarm signal for the transmission header. The method may further include generating a transmission header spreading signal by allocating a spreading code different from the code.

The digital multimedia broadcasting transmission method may further include modulating the emergency information spreading signal, the alarm spreading signal, and the transmission header spreading signal, and adding the modulated information to the digital multimedia broadcasting (DMB) signal.

A first set of spreading codes are assigned to the at least one emergency information signal, a second spreading code is assigned to the emergency information alarm signal, and a third allocation code is assigned to the transmission header. The magnetic and cross correlation properties may be excellent.

The length of the first set of spreading signals may be changeable.

The transmission information may include channel coding, interleaving and spreading code related information.

The at least one emergency information signal is an emergency information signal for providing at least one service, and the at least one service may be based on different service purposes or service areas.

The at least one emergency information signal may pass through different channel coding means and an interleaver.

The alarm spread signal may be transmitted through a synchronization channel of the transmission frame, and the emergency information spread signal may be transmitted through an information channel of the transmission frame.

In order to achieve the above object, a digital multimedia broadcasting (DMB) transmitting apparatus includes at least one emergency information signal, the emergency information signal including at least one of an emergency signal and additional information, and the at least one emergency. A signal generator for generating an emergency information alarm signal for informing the occurrence of an information signal, and assigning different spreading codes to the at least one emergency information signal and the emergency information alarm signal to generate at least one emergency information spread signal and an alarm spread signal The spreading signal generator may include a transmission unit for transmitting the emergency information spreading signal and the alarm spreading signal through a transmission frame.

A method for receiving a digital multimedia broadcast (DMB) by a terminal for achieving the above object includes receiving a digital multimedia broadcast (DMB) signal, and receiving an emergency information alarm signal from a spread signal of the received digital multimedia signal. Acquiring and obtaining information related to the occurrence of the emergency information signal, wherein the emergency information signal includes at least one of an emergency signal and additional information; and synchronizing and despreading the spread signal through a spreading code when the emergency information signal is generated. And acquiring at least one emergency information signal. Since the emergency information notification signal and the at least one emergency information signal are assigned different spreading codes, they may be despread using different spreading codes. .

The digital multimedia broadcasting receiving method may further include obtaining the transmission header including the configuration and transmission information of the at least emergency information signal by despreading the spread signal, wherein the transmission header includes the at least one emergency information signal and The spreading signal may be despread through a spreading code different from the spreading signal assigned to the emergency information alarm signal.

The transmission information included in the transmission header may include channel coding, interleaving and spreading code related information, and may select and receive any one service of the at least one emergency information signal based on the transmission information.

The digital multimedia broadcasting receiving method may further include receiving and synchronizing an OFDM signal of the received digital multimedia signal, performing demodulation and decoding, and acquiring an existing signal according to a selection related to the use of a disaster service.

The at least one emergency information signal is despread using a first set of spreading codes, the emergency information alarm signal is a second spreading code, and the transmission header is spread using a third allocation code, wherein the first set of spreading signals May be excellent in magnetic and cross-correlation properties.

The at least one emergency information signal is an emergency information signal for providing at least one service, and the at least one service may be based on different service purposes or service areas.

The at least one emergency information signal may be obtained by performing channel decoding, deinterleaving and decoding after despreading.

In order to achieve the above object, a digital multimedia broadcasting (DMB) receiving apparatus includes: a receiver for receiving a digital multimedia signal, an emergency information alarm signal obtained from an spread signal of the received digital multimedia signal, and an emergency information signal-emergency The information signal includes at least one of an emergency signal and additional information-an emergency information alarm signal acquisition unit for acquiring information related to the occurrence of the emergency signal and the spread signal when the emergency information signal is generated and synchronized and despread by at least And an emergency information signal acquisition unit for acquiring one emergency information signal. Since the emergency information notification signal and the at least one emergency information signal are assigned with different spreading codes, they may be despread using different spreading codes. have.

A digital multimedia transmission / reception system for achieving the above object includes at least one emergency information signal, the emergency information signal including at least one of an emergency signal and additional information, and emergency information informing generation of the at least one emergency information signal. A transmitter for generating an alarm signal to generate a spread signal by assigning different spreading codes to the at least one emergency information signal and the emergency information alarm signal, and generating and transmitting a digital multimedia signal based on the generated spread signal; Receiving the digital multimedia signal, obtaining the emergency information alarm signal from the spread signal of the received digital multimedia signal, obtaining information related to the generation of the emergency information signal, and spreading the spread signal when the emergency information signal is generated Sync via But spread by obtaining at least one of the emergency information signal may include information about the emergency alarm signal and a reception section for despreading using the at least one emergency information signals with different spreading codes.

According to the digital multimedia broadcasting transmitting apparatus and method, the receiving apparatus and the method and the transmitting / receiving system of the present invention, at least one service is transmitted and spread as channel coding, interleaving and spreading codes, respectively, according to the purpose of the service, thereby increasing the service. In this case, the service can be increased by increasing the spreading code without major modification.

In addition, according to the digital multimedia broadcasting transmitting apparatus and method, the receiving apparatus and the method, and the transmitting and receiving system of the present invention, it is possible to transmit a specified spreading code corresponding to each service as a separate value to enable fast service reception at the receiver. .

1 is a view showing an example of a structure of a T-DMB (Terrestrial-Digital Multimedia Broadcasting) transmission frame to which the present invention is applied;
2 is a diagram illustrating an example of a transport layer of T-DMB to which the present invention is applied;
3 is a diagram illustrating an example of a DMB transmission / reception system;
4 is a view showing an example of a DMB transmitting apparatus of a disaster broadcasting system;
5 is a block diagram schematically showing the configuration of a digital media broadcast transmission device according to an embodiment of the present invention;
6 is a block diagram schematically showing the configuration of a digital media broadcast receiving apparatus according to an embodiment of the present invention;
7 and 8 illustrate an example of generating and transmitting an emergency information alarm signal and a spread signal for transmitting and receiving an emergency information signal;
9 and 10 illustrate another example of generating and transmitting an emergency information alarm signal and a spread signal for transmitting and receiving an emergency information signal;
11 is a diagram illustrating a system in which a DMB transmission / reception method according to the present invention is applied to an OFDM system;
12 is a view showing a T-DMB transmission frame structure to which the present invention is applied;
13 is a diagram illustrating an example of transmitting a spread signal according to the present invention.

As the present invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.

However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. In the following description of the present invention, the same reference numerals are used for the same elements in the drawings and redundant descriptions of the same elements will be omitted.

1 is a diagram illustrating an example of a structure of a T-DMB (Terrestrial-Digital Multimedia Broadcasting) transmission frame to which the present invention is applied.

Referring to FIG. 1, a transmission frame is composed of a synchronization channel and a data channel. The length of the transmission frame may be 96 ms as an example. The data channel may be classified into a fast information channel (FIC) and a main service channel (MSC).

The transmission system usually uses one transmission method. In order to transmit an emergency information signal and connect it with a receiver, an emergency information signal must be transmitted in a specific data section of a transmission frame. When the method of transmitting data and the method of transmitting an emergency information signal are the same, the emergency information signal is being transmitted. Occupies a data rate. Therefore, the transmission of data is affected by the transmission of the emergency information signal. Here, the emergency information signal may include the additional information signal. Hereinafter, the emergency information may mean emergency / additional information.

However, if emergency information is transmitted in a null symbol period once every two frames through TII (Transmitter Identification Information) of a synchronization channel rather than a data period, the emergency information signal does not occupy the data rate being transmitted.

2 is a diagram illustrating an example of a transport layer of T-DMB to which the present invention is applied.

Referring to FIG. 2, the T-DMB system is based on a DAB (Digital Audio Broadcasting) system. The audio service basically transmits two channels or multiple channels of audio. PAD (Program Associated Data) is an audio-linked additional data service, DLS (Dynamic Layer Service) can provide the song title, singer information, traffic information, etc., TDC (Transparent Data Channel) is not limited in format ( It is a protocol that provides a function to transmit data in a unique format defined by a broadcasting company. A broadcasting web site (BWS) can provide a real-time news service, and a slide show (JPEG Slide Show) can provide a web camera linked service. Interactive services are also possible.

NPAD (Non-PAD) is an independent channel service, which is a service of a method transmitted in a separate method. MOT (Multimedia Object Transfer) protocol among data transmission protocols is a protocol for downloading files to a receiver and can be used for periodically downloading data. IP tunneling (Internet Protocol Tunneling) provides a function for providing a passage for IP packets, and TPEG (Transport Protocol Expert Group) can provide real-time traffic information and additional information services.

In particular, an emergency warning system (EWS) of a fast information data channel (FIDC) is a data area that can be allocated for transmitting emergency information.

3 is a diagram illustrating an example of a DMB transmission / reception system. As shown in FIG. 3, the DMB transmission / reception system may include a DMB transmission apparatus 300 and a DMB reception apparatus 350 and a network 340 connecting the transmission and reception apparatuses 300 and 350. Here, the transmitting device 300 may be a base station. In addition, the receiving device 350 may be a terminal.

Referring to FIG. 3, the DMB transmitter 300 includes a controller 310, an emergency information signal generator 312, an emergency information alarm signal generator 314, an existing signal generator 316, and a transmitter 320. It may include. First, when emergency information occurs, the controller 310 controls the emergency information signal generator 312 and the emergency information alarm signal generator 314 to generate an emergency information signal and an emergency information alarm signal, respectively. According to an embodiment of the present invention, the emergency information signal generator 312 may generate an emergency information spread signal by spreading different emergency information signals using different spread codes. In addition, the emergency information signal generator 312 and the emergency information alarm signal generator 314 may generate an emergency information spread signal and an alarm spread signal by performing spread using different spread codes. The generated emergency information spread signal and the alarm spread signal may be transmitted to the receiving device 350 together with the existing signal generated by the existing signal generator 316 through the transmitter 320. The existing signal generator 316 may be configured to generate an existing broadcast signal which has been transmitted before the emergency information is generated.

The network 340 is a component for connecting the DMB transmitting apparatus 300 and the DMB receiving apparatus 350 and may be a wireless or wired network. The network 340 may include a broadcasting network.

The DMB receiving apparatus 350 may include a receiver 360, an emergency information signal detector 362, an emergency information alarm signal detector 364, and an existing signal acquirer 366. The receiver 360 receives a DMB signal including an emergency information spread signal and an emergency information alarm signal from the DMB transmitter 300. The receiver 360 classifies the emergency information alarm signal, transmits the emergency information alarm signal to the emergency information alarm signal detector 364, and determines whether emergency information has occurred through the emergency information alarm signal. When the occurrence of the emergency information signal is detected through the emergency information alarm signal, the emergency information signal detection unit 362 may perform despreading using the spreading code of the emergency information spread signal to obtain the emergency information signal. The existing signal acquisition unit 366 may acquire the existing signal when selecting to receive the existing signal according to the use selection for the disaster broadcasting service.

4 is a diagram illustrating an example of an apparatus for transmitting a DMB in a disaster broadcasting system.

Referring to FIG. 4, in a multimedia broadcasting system such as a disaster broadcasting system, the DMB transmitting apparatus includes an emergency information alarm signal generator 410, an emergency information signal generator 412, a large capacity emergency information signal generator 414, and a transmission frame. The generator 420 includes an orthogonal frequency division multiplexing (OFDM) signal generator 430, and a high power amplifier 440. The DMB transmitter for disaster broadcasting transmits a very short emergency information alarm signal indicating only the presence or absence of an emergency information signal such as a disaster through the broadcasting network through the synchronization channel of the DMB transmission frame, and emergency information including detailed information is separated from the data. Can be transmitted through the channel.

The emergency information alarm signal generator 410 may repeatedly generate the emergency information alarm signal periodically so as to inform whether or not an emergency information signal is generated through a null channel of a synchronization channel of a transmission frame of the terrestrial DMB. The emergency information signal generator 412 generates the frequency and code information of the emergency information alarm signal, the type of emergency information such as disaster broadcasting, the level of emergency information, the location of the disaster occurrence area, the disaster broadcasting message, the main disaster broadcasting channel number, and the like. Produced according to DMB broadcasting standard. This emergency information signal can be transmitted through the FIDC (especially, EWS) channel of the FIC. In this case, although not shown in the figure, a transport header may be provided based on information related to the configuration and service of the generated emergency information signal. The transmission header may be spread through an emergency information alarm signal and a spreading code different from the emergency information signal.

The large-capacity emergency information signal generator 414 generates a large-capacity emergency information signal as needed. This information may be sent over the MSC channel 426. Meanwhile, the transmission frame generator 420 generates a DMB transmission frame so that the signals can be transmitted through separate channels. That is, the emergency information alarm signal generates a DMB transmission frame so that the null channel 422 of the synchronization channel, the emergency information signal can be transmitted through the FIDC 422 of the FIC, and the large-capacity emergency information signal can be transmitted through the MSC 426. Thereafter, when the OFDM signal generator 430 modulates the DMB transmission frame to generate an OFDM signal, the high power amplifier (HPA) 440 amplifies and transmits the OFDM signal with a constant power.

The transmitter transmits an emergency information alarm signal indicating only whether emergency information is generated through a null channel 422 of a synchronization channel of a DMB broadcast, and an emergency information signal including detailed information through a separate channel FIDC 424. have. The receiver checks only the emergency information alarm signal even when the power switch of the receiver is turned off, and moves to the channel receiving the emergency information signal when it confirms that there is emergency information, so that emergency information can be received at any time while minimizing power consumption. Can be.

That is, an emergency information alarm signal is transmitted using a null symbol section of a transmission frame (when transmitting TII, a null symbol section without TII is used), and a simple disaster is notified using FIDC 424. The matter may be communicated using the MSC 426. When transmitting emergency information through the FIDC 424, the service using the existing FIDC 424 must be stopped.

Since the emergency information signal is being transmitted through the FIDC 424, data of the FIDC can be read after all operations (eg, synchronization and demodulation) of the receiver are normally operated. In order for all receiver operations to work properly, the receiver field strength of the receiver must be greater than the minimum field strength available to receive existing services.

When the emergency information alarm signal is transmitted through a null symbol period, in particular, when the emergency information alarm signal is transmitted through a null symbol period without TII in the transmission using TII, whether there is an emergency information signal at any point in time. At least two frames of processing are required to determine whether or not.

5 is a block diagram schematically illustrating a configuration of a digital media broadcast transmission device according to an embodiment of the present invention. As shown in FIG. 5, the apparatus for transmitting digital media broadcasting according to an embodiment of the present invention generates an OFDM signal based on at least one existing signal (Source: 510-1,..., 510 -N). Configuration, configuration to spread the at least one emergency information signal 512-1, ..., 512-N to generate an emergency information spread signal, configuration to spread the transmission header 514, emergency information alarm signal 516 And spreading the signal to generate an alarm spread signal, and adding the signal to transmit the received signal to the receiving device through a high frequency conversion.

Referring to FIG. 5, at least one existing signal 510-1,..., 510 -N is transmitted through digital multimedia broadcasting before generation of the emergency information signals 512-1,..., 512 -N. It may mean a signal. The at least one existing signal 510-1,..., 510 -N may be a plurality of broadcast signals according to channels. Each of the plurality of broadcast signals may be encoded through a separate source codec and may be channel coded and interleaved by different channel coding means and interleavers. At least one existing signal (510-1, ..., 510-N) passed through the process is multiplexed through a mux (mux) and modulated through an OFDM modulator with an FIC synch, and then It may be transmitted to the receiving device through an upconverter and a high frequency amplifier (HPA). In this case, in some cases, the mux may be located between the source codec and the channel coding and the interleaver. At this time, when the emergency information signal (512-1, ..., 512-N) occurs, the emergency information signal (512-1, ..., 512-N), the transmission header 514 and the emergency information alarm signal (516) ) Can be added to the spread signal.

The at least one emergency information signal 512-1,..., 512 -N may be a signal that provides at least one service. That is, it may be a signal having different service purposes or service areas. For example, emergency information signal 1 512-1 has a radius of 1 km for service area, emergency information signal 2 512-2 has a radius of 2 km for service area, and emergency information signal 3 512-1 has a radius of service area. It may be an emergency information signal having different service areas, such as 4 km. In addition, the purpose of each emergency information signal (512-1, ..., 512-N) can be different. The at least one emergency information signal 512-1,..., 512 -N may be coded through different source codec, and channel coded and interleaved by different channel coding means and interleaver. .

According to an embodiment of the present invention, different spreading codes 522-1, ..., for the at least one emergency information signal 512-1, ..., 512-N which have passed the above process 522-N). PN (Pesudo Noise) code may be used as the spreading code. In this case, the different spreading codes 522-1,..., 522 -N allocated to each other may be spreading codes constituting one set. In addition, the spreading codes 522-1,..., 522 -N may be configured as a set having excellent magnetic and cross correlation properties. Moreover, the length of spreading codes 522-1,..., 522 -N may be changeable. The lengths of the spreading codes 522-1,..., 522 -N may be changed according to performance, and the lengths of the spreading codes 522-1,. By spreading through the spreading codes 522-1,..., 522 -N, an emergency information spreading signal can be generated and transmitted separately from the existing signal. An information spread signal can be transmitted.

The DMB transmitting apparatus may transmit the transmission header 514 together with the emergency information signals 512-1, ..., 512-N. The transmission header 514 transmits the information related to the configuration of the emergency information signals 512-1, ..., 512-N and the services of each of the emergency information signals 512-1, ..., 512-N. May contain information. In this case, the transmission information may be information related to channel coding, interleaving, and spreading codes of the emergency information signals 512-1 to 512-N. Through this, the receiving device can acquire the spreading code-related information and can simply despread the emergency information assurance signal. The transmitting device encodes a transmission header 514 through a source codec and performs interleaving through an interleaver. Then, spreading is performed using spreading code 524. The spreading code 524 may preferably use a code different from the spreading codes 512-1, ..., 512-N that were used for the emergency information signals 512-1, ..., 512-N. have.

Next, the DMB transmitting device may spread the emergency information alarm signal 516 to transmit to the receiving device. When the emergency information alarm signal 516 is spread using the spreading code 526 and then transmitted, since the emergency information alarm signal 516 is not transmitted through the null symbol period, processing of two frames is not required. The spreading code 526 used for spreading the emergency information alarm signal 516 is a spreading code 522 that was used for spreading the emergency information signals 512-1, ..., 512-N and the transmission header 514. -1, ..., 522-N, 524 may be a different code.

The transmitting device spreads by adding a spread signal for the emergency information signals 512-1, ..., 512-N, a spread signal for the transmission header 514, and a spread signal for the emergency information alarm signal 516. A signal may be generated and added to an existing signal (OFDM signal) and transmitted. In addition, the spread signal transmitted has a relatively low power compared to the conventional OFDM signal, and may have little effect on the existing system, such as adding to a portion that does not affect the existing signal. Other data may be transmitted to some of the added signals.

6 is a block diagram schematically illustrating a configuration of a digital media broadcast receiving apparatus according to an embodiment of the present invention. As shown in FIG. 6, the DMB receiving apparatus may include a receiving RF module 610, a configuration for obtaining an existing signal, a configuration for recognizing an emergency signal, and a configuration for obtaining an emergency information signal.

Referring to FIG. 6, the receiving module 610 receives a digital multimedia broadcasting signal including a spread signal. If there is no signal related to emergency information (which may include an emergency information signal, an emergency information alarm signal, and a transmission header), an OFDM signal related to a broadcast signal may be received to receive synchronization, OFDM demodulation, and service according to a general process. Channel decoding and deinterleaving according to a selection are performed, and finally, an existing signal is obtained by performing source decoding through a source decodec (620). Even when a signal related to emergency information exists, the receiving module 610 distinguishes an existing signal from a spread signal, despreads the spread signal using a spreading code, and the OFDM signal is used to select a disaster service as described above. Accordingly, after channel decoding and deinterleaving are performed, an existing signal of a specific channel may be obtained by source decoding (620).

When there is a signal related to emergency information, the occurrence of the emergency information signal is recognized through the emergency information alarm signal simultaneously with receiving the OFDM signal. When the generation of the emergency information signal is recognized, spreading code synchronization and reception synchronization may be performed. And you can choose to be a disaster service. This can be input from the user through the user interface. The user may choose to continue receiving existing signals through the disaster service selection. In this case, the receiving process of the emergency information signal may not be performed.

After spreading code synchronization is performed, the receiving device may obtain information about the transmission header 614 by despreading the spreading signal and performing channel decoding. The transmission header 614 includes transmission information (channel coding information, interleaving related information, and spreading code information) for each service of the at least one emergency information signal and the configuration of the emergency information signal. Can be received. After the service is selected through the transmission header, despreading is performed based on spreading code information of the selected emergency information spreading signal, channel decoding and deinterleaving operation is performed, and source decoding is performed to obtain a desired emergency information signal. 612.

According to another embodiment of the present invention, the emergency information signal may be obtained by despreading at least one emergency information spread signal without obtaining the transmission header 614 and the service selection process.

In this case, the at least one emergency information spreading signal may have different designated spreading codes, and this value may be transmitted separately through a transmission header, and a receiving device may quickly receive a service through the separately transmitted spreading code related information. You can do that.

7 and 8 illustrate an example of generating and transmitting an emergency information alarm signal and a spread signal for transmitting and receiving an emergency information signal.

Referring to FIG. 7, a PN (Pseudo Noise) code generator generates one PN code at a transmitter. A bipolar converter converts the message data and the PN codes, respectively, and multiplies them to generate and transmit a spread signal. Referring to FIG. 8, after the receiver receives the spread signal, the receiver multiplies this value by a value obtained by converting the PN code into a bipolar converter and integrates the result of the integrator, and decodes the message data decoder to obtain message data.

For example, if the message data is '1,0', the result of the conversion through the bipolar converter is '1, -1', and if the PN code is '0,1,0,1', the result of the conversion through the bipolar converter Is '-1,1, -1,1'. Multiplying the result of each conversion yields '-1,1, -1,1' and '1, -1,1, -1'. Multiply the previously generated PN code '0,1,0,1' by '-1,1, -1,1', which is converted to a bipolar converter, and '1,1,1,1' and '-1 , -1, -1, -1 'can be obtained and' 4, -4 'can be obtained by integrating with the integrator. Decoding this with a message data decoder can obtain '1,0', which is the first message data.

Since only one PN code is generated, the cross correlation between each codeset of the PN code is not important, and the auto correlation performance with oneself is important. If the autocorrelation property is good, the receiver can effectively detect the PN code and can show excellent performance in the multipath environment. However, such a code set may not be suitable to be assigned to at least one emergency information signal. This is because one set of spreading codes assigned to at least one emergency information signal is excellent in auto and cross correlation characteristics. However, it may be suitable for use as a spreading code between the emergency information signal and the emergency information alarm signal, between the emergency information signal and the transmission header, and between the emergency information alarm signal and the transmission header.

As another embodiment, transmission and reception may be performed using quadrature phase shift keying (QPSK), and the spreading signal generation method of FIGS. 7 and 8 described above may be applied to a real part and an imaginary part, respectively, to spread. Generate a signal.

9 and 10 illustrate another example of generating and transmitting an emergency information alarm signal and a spread signal for transmitting and receiving an emergency information signal.

Referring to FIG. 9, the PN code generator generates and transmits four different PN codes from message data. Referring to FIG. 10, a receiver multiplies a value obtained by converting a PN code into a bipolar converter and a received result, integrates the result of integrator, and decodes the message data decoder to obtain message data.

For example, when the message data is one of '00, 01,10,11 ', the PN code generator generates four different PN codes' 1,1,1,1 ',' 1, -1,1,- One of '1', '1,1, -1, -1' and '1, -1, -1,1' is generated and transmitted as a spread signal. That is, if the message data is' 00 ', the PN code is' 1,1,1,1'. If the message data is' 01 ', the PN code is' 1, -1,1, -1' and the message data is' 10 ', the PN code is' 1,1, -1, -1'. If the message data is' 11 ', the PN code is' 1, -1, -1,1'. Such PN codes are just an example, and the PN codes may be generated by a combination of other codes.

If the message data is '01', the transmitter generates a PN code '1, -1,1, -1' in the PN code generator and transmits the spread signal, and the receiver transmits the spread signal '1, -1,1, -1'. Receive '. At the receiver, PN codes' 1,1,1,1 ',' 1, -1,1, -1 ',' 1,1, -1, -1 'and' from PN code generator 1 to PN code generator 4, respectively. Generate 1, -1, -1,1 'and multiply the received spread signal by the value of each PN code. As a result, '1, -1,1, -1', '1,1,1,1,' '1, -1,1, -1' and '1,1, -1, -1' are obtained . Integrating with the integrator, it is '0', '4', '0' and '0', respectively. Since a non-zero value is obtained only from the PN code generated from the PN code generator 2, the message data is '01' when decoded by the message data decoder.

The method using the four code families transmits data using the generated code set. The better the correlation between the code sets, the more effectively it can be detected (best when 0). Therefore, a block for decoding at the receiver is needed as much as the code set.

 According to the present invention, since one set of spreading codes allocated to at least one emergency information signal is excellent in cross-correlation and auto-correlation characteristics, it is preferable to use a code set (or code family) in the above manner. can do. In this case, the length of the spreading code may be variable. As the length of the code increases, it is important to appropriately select the code length because the correlation property becomes worse.

11 illustrates a system in which a DMB transmission / reception method according to the present invention is applied to an OFDM system.

Referring to FIG. 11, a transmitter generates a spread signal using message data and a spreading code and transmits the spread signal together with an existing OFDM signal. The receiver may receive an OFDM signal and a spread signal together, despread the spread signal using a spread code, and integrate the obtained signal to obtain an emergency information alarm signal, an emergency information signal, and a transmission header.

12 is a diagram illustrating a T-DMB transmission frame structure to which the present invention is applied.

Referring to FIG. 12, a transmission frame includes a synchronization channel, an FIC, and an MSC, and includes 76 symbols including null symbols of the sync channel. Each symbol includes a guard interval and a symbol data interval. A symbol reference symbol (PRS) may be transmitted to symbol 1.

13 is a diagram illustrating an example of transmitting a spread signal according to the present invention.

Referring to FIG. 13, the transmission frame is divided into a synch part and a data part, and an emergency information alarm signal is added to the sink part and transmitted, and the emergency information signal and a transmission header are added to the data part and transmitted. In this case, the sink and data portions may be sent over the entire portion of the transmission frame. At this time, the transmission frame of the added signal may or may not fit the existing DMB.

In the null symbol, the data portion may be transmitted and the sink portion may be transmitted.

In a part that does not significantly affect the reception performance, an emergency information alarm signal or an emergency information signal may be largely inserted.

In addition, since there may be a plurality of emergency information signals, data related to the plurality of emergency information signals may be transmitted in duplicate in the data portion of the transmission frame. The sink portion may be included in all of the plurality of data, only part of the plurality of data, or may be transmitted in duplicate with the plurality of data.

On the other hand, the addition of the emergency information alarm signal using the spreading code can be used not only for the signal for the receiver but also as a synchronization signal for the data using the spreading code.

The transmission frame is divided into the sink part, data and header part, and an emergency information alarm signal is added to the sink part and transmitted, and the emergency information signal is added to the data part and transmitted, but an important information signal includes an emergency information alarm signal or emergency information. Without adding a signal, it is possible to divide and send an emergency information alarm signal or an emergency information signal only to a specific part and a sink part and a data part. Only an emergency information alarm signal or an emergency information signal is added and transmitted only in a part that does not significantly affect the reception performance, and in this case, performance degradation of DMB reception can be minimized.

The length and position of the sync signal can be changed according to performance. However, as described above, the transmitter and the receiver must know the length and the appearance interval of the synchronization signal, respectively.

In FIG. 13, a separate spreading code may be used as a wake-up and another spreading code may be overlapped for data or transmission frame information. In this case, the spreading code may use a time division duplex (TDD) scheme or a code division duplex (CDD) scheme, and may use a mixture of the TDD and the CDD.

Although described above with reference to the drawings and embodiments, it does not mean that the scope of protection of the present invention is limited by the above drawings or embodiments, and those skilled in the art to the spirit of the present invention described in the claims It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the invention.

Claims (19)

In the digital multimedia broadcasting (DMB) transmission method by a base station,
Generating a plurality of emergency information signals having different service areas and an emergency information alarm signal informing of occurrence of the plurality of emergency information signals;
Allocating different spreading codes to the plurality of emergency information signals and the emergency information alarm signal to generate a plurality of emergency information spread signals and alarm spread signals; And
Transmitting the plurality of emergency information spreading signals and alarm spreading signals through a transmission frame,
The generating step,
Instead of multiplexing the plurality of emergency information signals using a mux, the plurality of emergency information spreading signals are assigned to the plurality of emergency information signals, respectively, to generate the plurality of emergency information spreading signals. Digital multimedia broadcasting transmission method, characterized in that the step of doing.
The method of claim 1,
Generating transmission header information including configuration and transmission information of the plurality of emergency information signals; And
And generating a transmission header spreading signal by allocating a spreading code different from a spreading code allocated to the plurality of emergency information signals and the emergency information alarm signal to the transport header. .
The method of claim 2,
And modulating the emergency information spreading signal, the alarm spreading signal, and the transmission header spreading signal and adding the same to a digital multimedia broadcasting (DMB) signal.
The method of claim 2,
A first set of spreading codes are assigned to the plurality of emergency information signals, a second spreading code is assigned to the emergency information alarm signal, and a third spreading code is assigned to the transmission header.
And the first set of spreading codes is excellent in self and cross-correlation characteristics.
The method of claim 4, wherein
And a length of the first set of spread signals is changeable.
The method of claim 2,
The transmission information includes channel coding, interleaving and spreading code related information.
The method of claim 2,
Each of the plurality of emergency information signals is an emergency information signal for providing a plurality of services,
And wherein the plurality of services are based on different service purposes or service areas.
The method of claim 2,
And the plurality of emergency information signals pass through different channel coding means and an interleaver.
The method of claim 2,
And the alarm spread signal is transmitted through a synchronization channel of the transmission frame, and the emergency information spread signal is transmitted through an information channel of the transmission frame.
In the digital multimedia broadcasting (DMB) transmitting apparatus,
A signal generator configured to generate a plurality of emergency information signals having different service areas and an emergency information alarm signal informing generation of the plurality of emergency information signals;
A spreading signal generator for generating a plurality of emergency information spreading signals and an alarm spreading signal by allocating different spreading codes to the plurality of emergency information signals and the emergency information alarm signal; And
A transmission unit for transmitting the emergency information spreading signal and the alarm spreading signal through a transmission frame,
The spread signal generator,
Instead of multiplexing the plurality of emergency information signals using MUX, the plurality of emergency information signals are allocated to the plurality of emergency information signals by assigning different spreading codes designated for the different service areas, respectively. Digital multimedia broadcasting transmission apparatus, characterized in that.
In the method for receiving a digital multimedia broadcast (DMB) by a terminal,
Receiving a digital multimedia broadcasting (DMB) signal;
Acquiring an emergency information alarm signal from the spread signal of the received digital multimedia signal to obtain information related to generation of an emergency information signal, the emergency information signal including at least one of an emergency signal and additional information;
Acquiring a plurality of emergency information signals by synchronizing and despreading the spread signal through a spreading code when the emergency information signal is generated,
Since the emergency information notification signal and the plurality of emergency information signals are assigned with different spreading codes, they are despread using different spreading codes.
The plurality of emergency information signals are signals that are not multiplexed by the MUX at the transmitter, and are despread using different spreading codes designated for different service areas.
The method of claim 11,
Despreading the spread signal to obtain a transmission header including configuration and transmission information of the plurality of emergency information signals,
The transmission header is despread through a spreading code different from a spreading signal allocated to the plurality of emergency information signals and the emergency information alarm signal.
The method of claim 12,
Transmission information included in the transmission header includes channel coding, interleaving and spreading code related information,
And receiving and selecting any one service among the plurality of emergency information signals based on the transmission information.
The method of claim 12,
And receiving and synchronizing an OFDM signal of the received digital multimedia signal according to a selection related to the use of a disaster service, performing demodulation and decoding, and acquiring an existing signal.
The method of claim 12,
The plurality of emergency information signals are despread using a first set of spreading codes, the emergency information alarm signal is a second spreading code, and the transmission header is spread using a third spreading code.
And the first set of spreading signals is excellent in self and cross-correlation characteristics.
The method of claim 12,
Each of the plurality of emergency information signals is an emergency information signal for providing a plurality of services,
And the plurality of services are based on different service purposes or service areas.
The method of claim 12,
The plurality of emergency information signals are obtained by performing channel decoding, deinterleaving and decoding after despreading.
In the digital multimedia broadcasting (DMB) receiving apparatus,
Receiving unit for receiving a digital multimedia signal;
An emergency information alarm signal obtaining unit obtaining an emergency information alarm signal from the spread signal of the received digital multimedia signal to obtain information related to generation of the emergency information signal;
When the emergency information signal is generated includes an emergency information signal acquisition unit for obtaining a plurality of emergency information signals by synchronizing and despreading the spreading signal through a spreading code,
Since the emergency information notification signal and the plurality of emergency information signals are assigned with different spreading codes, they are despread using different spreading codes.
The plurality of emergency information signals are signals that are not multiplexed by the MUX at the transmitter, and are despread using different spreading codes designated for different service areas. delete

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