KR100704957B1 - Satellite digital multimedia broadcasting system and method - Google Patents

Abstract

The present invention is to transmit broadcast channel information used for satellite digital multimedia broadcasting by using a terrestrial mobile communication station having sufficient stability of information transmission, and includes broadcast data in a digital multimedia broadcasting channel and transmits it to satellites and digital multimedia broadcasting. A broadcast station for transmitting broadcast channel information used to extract broadcast data from a channel to a satellite and a terrestrial mobile communication station, a satellite for relaying a pilot channel including a multimedia broadcast channel and broadcast channel information to the ground, and broadcast channel information from a broadcast station. Extracting the broadcast data contained in the digital multimedia broadcasting channel transmitted from the satellite by using the broadcast channel information transmitted from the terrestrial mobile communication station and the terrestrial mobile communication station, which are received and transmitted to the receiving terminal through the terrestrial wireless communication network. It includes a receiving terminal.

DMB, terrestrial mobile station, pilot channel, broadcast channel information

Description

Satellite digital multimedia broadcasting system and satellite digital multimedia broadcasting method {SATELLITE DIGITAL MULTIMEDIA BROADCASTING SYSTEM AND METHOD}

1 is a simplified block diagram of a satellite multimedia broadcasting system according to the present invention.

2 shows the structure of a pilot channel;

3 is a flow chart illustrating a satellite DMB method.

(Explanation of symbols for the main parts of the drawing)

10: broadcasting station

20: satellite for DMB

30: ground mobile communication station

40: receiving terminal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital multimedia broadcasting system using satellites, and more particularly, to a method of providing digital multimedia broadcasting with improved quality by combining a satellite digital multimedia broadcasting system and a terrestrial mobile communication station.

Digital multimedia broadcasting using satellites (hereinafter referred to as DMB (Digital Multimedia Broadcasting)) uses satellites to receive high quality / high definition music broadcasting, traffic information, weather, sports, etc. through the frequency band of 1.4 ~ 2.7 ㎓. Broadcast service that can be output from.

In general, in satellite broadcasting or satellite communication using an artificial satellite, communication is possible only when a direct line of sight (LOS) with the satellite is guaranteed. That is, when the line of sight is disturbed by the feature, an area of poor quality of the communication service through the satellite occurs. Such a poor reception state is called a gap, and in order to improve the reception state of such an area, a method of additionally installing a terrestrial relay station which relays a signal from a satellite and retransmits it to a receiving terminal is used. Such relay stations are generally referred to as gap fillers. In addition, even when the receiving terminal is moving, a gap filler is required to provide an uninterrupted satellite broadcasting service. In addition, when constructing satellite DMB, not only a gap filler system should be established on the ground to ensure the mobility of the receiving terminal, but also fading due to multipath propagation formed by the movement of the receiving terminal. You should also remove the phenomenon. Currently, technologies suitable for a multipath environment include orthogonal frequency division multiplexing (OFDM) and code division multiplexing (CDM). Among them, the OFDM scheme is currently applied to the European DMB service.

In order to demodulate or decode digital data propagated from a satellite at a receiving terminal to predetermined broadcast information, synchronization with a satellite is required, and the necessary information is a pilot symbol. The pilot symbol is included in a predetermined packet of a pilot channel and transmitted. A unique word is used in a packet section in which a pilot symbol is not transmitted in the pilot channel. A frame counter, control data including various types of information about a channel for broadcast data propagated from satellites, and the like.

The structure of this pilot channel is shown in FIG. The pilot channel has a basic frame unit of 12.75 ms and all 51 pilot symbol units. One pilot symbol unit includes one pilot symbol PS and one satellite broadcast control data D1 to D51. Pilot symbols are all '1' data. Of the satellite broadcast control data, D1 and D2 represent a unique word and a frame counter, respectively, and the remaining D3 to D50 are control data for a broadcast channel, and D51 is reserved.

However, as described above, in the satellite broadcasting system, the distance between the receiving terminal and the satellite is very far, so that the strength of the radio wave received by the receiving terminal is weak, and when the line of sight is disturbed by the feature or fading occurs, the transmission is performed. There is a high possibility that the information to be distorted. In this case, when an error occurs due to distortion of a pilot symbol or control data of a pilot channel, the error is transmitted to the receiving terminal as it is, and the probability of an error occurring in relation to the reproduction of the digital multimedia broadcasting in the receiving terminal also increases. . Therefore, it can be said that transmission stability of information included in a pilot channel is more important than stability in transmission of broadcast information.

In order to solve the problems described above, the present invention is to transmit the pilot symbol and broadcast channel information used for satellite digital multimedia broadcasting using a terrestrial mobile communication station is provided with a number of base stations and the stability of information transmission sufficiently It is an object of the present invention to improve the reception performance of satellite digital multimedia broadcasting.

In order to solve this problem, the satellite digital multimedia broadcasting system according to the present invention includes a broadcast channel information used to include broadcast data in a digital multimedia broadcasting channel and transmit it to a satellite and extract broadcast data from the digital multimedia broadcasting channel. And a terrestrial mobile communication station which receives broadcast channel information from a satellite and a broadcasting station that relays a pilot channel including a broadcasting station, a multimedia broadcasting channel, and broadcast channel information to the ground, and transmits the information to a receiving terminal through a terrestrial wireless communication network. And a receiver terminal for extracting broadcast data included in a digital multimedia broadcast channel transmitted from a satellite by using broadcast channel information transmitted from a terrestrial mobile communication station.

In addition, the receiving terminal stores the transmitted broadcast channel information, and reconstructs the stored broadcast channel information in synchronization with the pilot channel from the satellite, characterized in that for extracting the broadcast data.

The broadcast channel information transmitted from the broadcast station to the terrestrial mobile communication station is broadcast channel information not stored in the terrestrial mobile communication station or the receiving terminal.

The broadcast channel information transmitted from the terrestrial mobile communication station to the receiving terminal is characterized in that the broadcasting channel information is not stored in the receiving terminal.

In addition, the pilot channel includes a pilot symbol, a unique word, a frame counter, and the broadcast channel information for demodulating or decoding the broadcast data included in the digital multimedia broadcast channel.

The terrestrial mobile communication station and terrestrial wireless communication network may be a mobile communication station and a wireless communication network using CDMA, TDMA, and FDMA.

In addition, according to the present invention, a satellite digital multimedia broadcasting method includes transmitting broadcast data to a satellite by including broadcast data in a digital multimedia broadcasting channel at a broadcast station and simultaneously transmitting broadcast channel information to the satellite and terrestrial mobile communication stations. And relaying a pilot channel including broadcast channel information to the ground, receiving broadcast channel information from a terrestrial mobile communication station and transmitting the received broadcast channel information to a receiving terminal through a terrestrial wireless communication network, and a broadcast channel received from a receiving terminal via a terrestrial wireless communication network. Extracting broadcast data included in the digital multimedia broadcasting channel transmitted from the satellite by using the information.

The method may further include receiving and storing broadcast channel information transmitted from a receiving terminal in advance, and reconfiguring the stored broadcast channel information in synchronization with a pilot channel from a satellite, and broadcasting using reconstructed broadcast channel information. Characterized in that the data is extracted.

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

1 is a diagram briefly showing a configuration of a satellite multimedia broadcasting system according to the present invention.

The broadcasting station 10 converts high quality / high definition music broadcasting, traffic information, weather, sports, and the like into digital broadcasting data, undergoes predetermined modulation and / or encoding, and then converts the data into the satellite 20 as digital multimedia broadcasting data. send. At the same time, the broadcast station 10 includes information including a pilot symbol, a unique word, a frame counter, broadcast channel information for demodulating / decoding broadcast data included in a digital multimedia broadcasting channel, or information for recovering incorrectly transmitted data. Is transmitted to the ground mobile communication station 30 through a predetermined wired or wireless communication network.

The satellite 20 for digital multimedia broadcasting receives various types of information for digital multimedia broadcasting transmitted from the broadcasting station 10, and relays / transmits it to the ground again. Such digital multimedia broadcasting data includes broadcasting data for audio / video broadcasting. In addition, the digital multimedia broadcasting data includes a receiving terminal 40 and a satellite 20, a receiving terminal 40 and a digital multimedia broadcasting terminator or a terrestrial mobile communication station 30, and a satellite 20 and a digital multimedia broadcasting ground. A pilot channel including a pilot symbol for synchronizing with the repeater or the terrestrial mobile communication station 30 and various kinds of information used for extracting data for digital multimedia broadcasting from information included in the digital multimedia broadcasting channel is further included. .

The terrestrial mobile communication station 30 includes a wireless communication network using a land mobile communication technology such as CDMA, TDMA, FDMA, etc. currently commercially available, and receives and transmits various types of data transmitted from the satellite 20 or the broadcasting station 10. It propagates to a predetermined receiver through a communication network. The ground mobile communication station 30 includes all the communication equipment constituting the above ground wireless communication network. In addition, the terrestrial mobile communication station preferably further comprises an appropriate demodulation / decoding device and a modulation / coding device for receiving and transmitting information transmitted from satellites or broadcasting stations.

The receiving terminal 40 is a terminal capable of receiving various data transmitted from the terrestrial mobile communication station 30 and digital multimedia broadcasting data transmitted from the satellite 20 and outputting the image or sound. It is preferable that the communication / communication terminal is also capable of communication. That is, the reception terminal 40 includes a satellite DMB receiver with a cellular phone function, a cellular phone, a PDA, a notebook computer and the like.

The pilot channel and the DMB channel are composed of frames divided into a predetermined number, as described with reference to FIG. 2. In order to extract and acquire broadcast data included in the DMB channel, the receiving terminal 40 synchronizes the receiving terminal 40 to the DMB channel using a pilot symbol and extracts desired audio / video broadcast data from the DMB channel. The broadcast channel information including data for estimating the information and the transmission characteristics of the DMB channel and correcting the data of the DMB channel is used.

For each component in such satellite DMB system, synchronization of each channel is very important. Therefore, at least a pilot channel should secure communication stability and distortion.

By the way, the broadcast channel information included in the pilot channel often includes a known standardized pattern. Thus, the broadcast terminal information that is formatted and predicted in this way may be received by the terrestrial mobile communication station 30 in place of the satellite 20. It is the idea of the present invention to transmit to the (40) side. That is, the pilot symbol of the pilot channel is composed of a '1' signal of a predetermined bit at the head of the frame. The broadcast channel information is information for decoding and demodulating DMB broadcast data, and since the variability thereof is not large, the same information is often transmitted repeatedly.

The broadcast station 10 transmits such repetitive information to the terrestrial mobile communication station 30 in advance, and broadcast channel information after a predetermined repetition period is transmitted from the terrestrial mobile communication station 30 to the receiving terminal 40. In addition, if the repetitive pattern of the broadcast channel information is transmitted in advance from the terrestrial mobile communication station 30 to the receiving terminal 40, the receiving terminal 40 stores it, and when the DMB reception request for a specific channel is received in advance. It is also possible to extract the desired broadcast data from the DMB channel using the stored broadcast channel information.

The broadcast channel information transmitted from the broadcasting station 10 to the terrestrial mobile communication station 30 or from the terrestrial mobile communication station 30 to the receiving terminal 40 side is transmitted to the terrestrial mobile communication station 30 or the receiving terminal 40. It is desirable to additionally transmit only if the information is different from the stored broadcast channel information. In this case, the stored broadcast channel information may be updated and stored with newly transmitted broadcast channel information.

In addition, the broadcast channel information may be transmitted from the broadcasting station 10 to the terrestrial mobile communication station 30 in synchronization with the digital multimedia broadcasting data, or only necessary broadcasting channel information may be transmitted after being compressed in a predetermined compression format. have. In addition, the terrestrial mobile communication station 30 may relay and transmit broadcast channel information, which is transmitted in the uncompressed state, directly to the receiving terminal 40 side, and decompresses the compressed broadcast channel information to be transmitted from the satellite 20. It may be transmitted to the receiving terminal 40 in synchronization with the channel, or may transmit the control data in the compressed state to the receiving terminal 40 as it is.

A method of transmitting / receiving DMB using the satellite DMB system will be described with reference to FIG. 3.

When the digital multimedia broadcasting is started (S10), the broadcasting station 10 transmits the DMB data for at least one digital broadcast to the satellite 20 through a predetermined DMB channel and at the same time pilot symbol and broadcast channel information for synchronizing to the DMB channel. Is transmitted to the satellite 20 (S11). In addition, the broadcast station 10 transmits broadcast channel information included in the pilot channel to the terrestrial mobile communication station 30 (S21).

The DMB data and pilot symbols transmitted to the satellite 20 are relayed from the satellite 20 and transmitted to the ground (S12). The DMB data transmitted to the ground is received by the receiving terminal 40 and then used to watch the multimedia broadcast.

The terrestrial mobile communication station 30 that has received the broadcast channel information transmitted from the broadcast station 10 transmits the broadcast channel information to the receiving terminal 40 side again (S22). Then, the receiving terminal 40 stores the transmitted broadcast channel information in a predetermined memory (S23).

At this time, the broadcast channel information transmitted from the terrestrial mobile communication station 30 is not necessarily stored in the memory of the receiving terminal 40 when the general form included in the pilot channel is not processed into a predetermined form. However, in order to replace the repeated broadcast channel information, it is preferable to store the repeated information.

The receiving terminal 40 acquires the pilot symbol through the DMB data and the pilot channel through the DMB channel transmitted from the satellite 20, and tries to receive from the DMB data of the DMB channel using previously stored broadcast channel information. The broadcast data to be demodulated is decoded and decoded (S13, S14).

Although the present invention has been described with reference to one embodiment as an example, the present invention is not limited thereto. In the satellite digital multimedia broadcasting system, broadcast channel information included in a pilot channel is transmitted using a terrestrial mobile communication station and received at a receiving terminal. As long as it is possible to perform digital broadcasting, appropriate modifications and variations will be possible by those skilled in the art.

In addition, the frequency band used by the broadcast channel information transmitted from the broadcast station to the terrestrial mobile communication station and the broadcast channel information transmitted from the terrestrial mobile communication station to the receiving terminal may be the same or different.

In addition, the DMB channel and the pilot channel may use any one of the OFDM communication method, the CDM communication method, the TDM communication method, and the FDM communication method for satellite communication.

According to the present invention made up of the above-described configuration, a pilot channel necessary for digital multimedia broadcasting between a satellite and a receiving terminal can be transmitted without error rate by using a terrestrial mobile communication station having a stable transmission of information. Digital multimedia broadcasting reception performance is improved than when broadcasting channel information is received. In addition, the unique word and frame counter of the pilot channel can be used as a pilot symbol, thereby improving the synchronization method by the pilot channel.

Claims (11)

delete A satellite digital multimedia broadcasting system for providing a broadcasting service using a satellite relaying a multimedia broadcasting channel and a pilot channel to the ground, A broadcasting station including broadcast data in a digital multimedia broadcasting channel and transmitting to satellites, and transmitting broadcast channel information for extracting the broadcasting data from the digital multimedia broadcasting channel to a terrestrial mobile communication station; A terrestrial mobile communication station receiving broadcast channel information from the broadcasting station and transmitting the broadcast channel information to a receiving terminal through a wireless communication network; A receiving terminal which receives the broadcast channel information from the terrestrial mobile communication station and extracts broadcast data included in the digital multimedia broadcasting channel from the satellite by synchronizing the received broadcast channel information with the pilot channel from the satellite; Satellite digital multimedia broadcasting system comprising a. The satellite digital multimedia according to claim 2, wherein the broadcast channel information transmitted from the broadcast station to the terrestrial mobile communication station is broadcast channel information not stored in the terrestrial mobile communication station or the receiving terminal among the broadcast channel information. Broadcasting system. 3. The satellite digital multimedia broadcasting system according to claim 2, wherein the broadcast channel information transmitted from the terrestrial mobile communication station to the receiver terminal is broadcast channel information not stored in the receiver terminal among the broadcast channel information. The satellite digital multimedia broadcasting of claim 2, wherein the pilot channel includes a pilot symbol, a unique word, a frame counter, and the broadcast channel information for demodulating or decoding the broadcast data included in the digital multimedia broadcasting channel. system. 6. The satellite digital multimedia broadcasting system according to any one of claims 2 to 5, wherein said terrestrial mobile communication station and terrestrial wireless communication network are mobile communication stations and wireless communication networks using CDMA, TDMA and FDMA. delete A satellite digital multimedia broadcasting method for providing a broadcasting service using a satellite that relays a multimedia broadcasting channel and a pilot channel to the ground, i) transmitting broadcast data to a satellite by including broadcast data in a digital multimedia broadcasting channel at a broadcast station, and transmitting broadcast channel information for extracting the broadcast data to the terrestrial mobile communication station; ii) receiving the broadcast channel information provided by the broadcast station from the terrestrial mobile communication station and transmitting the received broadcast channel information to a receiving terminal through a terrestrial wireless communication network; iii) the receiving terminal reconstructing the broadcast channel information received from the terrestrial mobile station in synchronization with a pilot channel from the satellite; iv) extracting the broadcast data transmitted through the digital multimedia broadcast channel from the satellite using the reconstructed broadcast channel information; Satellite digital multimedia broadcasting method comprising a. 9. The satellite digital multimedia broadcasting method according to claim 8, wherein the broadcast channel information transmitted to the receiver terminal is broadcast channel information not stored in the receiver terminal among the broadcast channel information. The satellite digital multimedia broadcasting of claim 8, wherein the pilot channel includes a pilot symbol, a unique word, a frame counter, and the broadcast channel information for demodulating or decoding the broadcast data included in the digital multimedia broadcasting channel. Way. 11. A satellite digital multimedia broadcasting method according to any one of claims 8 to 10, wherein said terrestrial mobile communication station and terrestrial wireless communication network are mobile communication stations and wireless communication networks using CDMA, TDMA, and FDMA.

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