KR101286335B1 - Receiver for Base Band Processing of Digital Multimedia Broadcasting - Google Patents

Abstract

The present invention performs baseband processing for receiving digital multimedia broadcasting (DMB) and extracting fast information channel (FIC) information and main service channel (MSC) information, but through an efficient new interface structure, audio / video decoders or other applications. It is possible to exchange the extracted information with a device. Accordingly, it is possible to flexibly interface with various devices using baseband processed FIC information and MSC information, thereby enabling the development and application of various devices related to DMB.

Digital multimedia broadcasting, baseband, receiver, interface, decoder,

Description

DMB Baseband Receiver {Receiver for Base Band Processing of Digital Multimedia Broadcasting}

1 is an embodiment of a DMB baseband receiver according to the present invention;

2 illustrates an embodiment of configuring an interface unit;

3 is an overview of the interface signal,

4 is an embodiment of configuring a control unit;

5 is an example of a process in which a controller operates according to an output selection signal;

6 is an embodiment of a baseband processor;

7 is a detailed embodiment of the baseband processor.

DESCRIPTION OF THE REFERENCE NUMERALS

10: DMB baseband receiver 11: baseband processing unit

11-1: Channel Separator 11-2: FIC Processor

11-3: MSC Processing Unit 12: Clock Generator

13: interface 21: output terminal

22: control unit 70: antenna

71-1: Tuner 71-2: Automatic Gain Controller

71-3: A / D converter 71-4: Mode detector

71-5: I / Q distributor 71-6: Signal synchronization unit

71-7: OFDM demodulator 71-8: Frequency deinterleaving unit

71-9: Channel distributor 72: FIC processing unit

73-1: time deinterleaving unit 73-2: convolutional decoder

73-3: energy reverse scrambler 73-4: channel distributor

73-5: convolutional deinterleaving unit 73-6: RS decoder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DMB baseband receiver, and in particular, performs baseband processing for receiving digital multimedia broadcasting (DMB) and extracting FIC information and MSC information. To work with

Digitalization of broadcasts has also affected analog radio broadcasts, speeding up the advent of digital radio broadcasts. In addition, digital multimedia broadcasting (DMB), which includes not only a voice radio broadcasting service but also a data service and a multimedia service, has become possible. DMB is resistant to noise and distortion occurring in the transmission channel, has a high transmission efficiency and has the advantage of enabling various multimedia services.

DMB adopted in Korea is based on Eureka-147 Digital Audio Broadcasting (DAB), which has been adopted as the European terrestrial radio standard. Added to improve the performance of multimedia broadcasting is the RS code (Reed-Solomon Code) and the convolutional interleaver that has a strong characteristic of burst errors that can occur in the transmission channel. The two additional blocks are applied to the DAB Ensemble input signal at the transmitter and provide an error rate low enough for video service even in a mobile reception environment.

The transmission channel of the DMB is a wireless mobile reception channel, and the amplitude of the received signal is not only time-varied, but also the Doppler Spreading phenomenon of the spectrum of the received signal occurs due to the influence of the mobile receiver. do. In consideration of the transmission and reception in such a channel environment, the DMB transmission method is based on Orthogonal Frequency Division Multiplexing. In addition, interleaving of signals in the time domain and the frequency domain may be performed to correct an error occurring in the transport channel.

DMB transmission signals are transmitted at a much smaller signal strength than conventional analog radio broadcast signals. In consideration of severe fading channel environments such as urban areas and mobile reception in automobiles, the actual received signal strength is very small. Therefore, the DMB receiver should be able to correct the transmission error by receiving the received signal as much as possible even in such a poor reception environment. In addition, considering the fact that it is a mobile receiving terminal, it is a key requirement of the DMB receiver to provide maximum reception performance at a limited cost.

Meanwhile, a terrestrial DMB receiver in the form of a System on Chip (SoC) means an audio / video decoder, but a baseband receiver does not include an audio / video decoder. Chip size is small. In addition, if the baseband receiver is configured independently, there is also the possibility of using other audio or video decoders. Therefore, various methods regarding the independent configuration of the baseband receiver are required. However, the interface specification for the DMB baseband receiver is not determined yet.

The present invention has been made to meet the above needs, and performs a baseband process for receiving a DMB signal and extracting FIC information and MSC information, and through the efficient interface structure, various audio decoders, video decoders, Its purpose is to provide a DMB baseband receiver that can communicate with other applications.

In order to achieve the above object, the DMB baseband receiver according to the present invention, the baseband processing unit for receiving the DMB signal to extract the FIC information and MSC information; A clock generator for generating a reference clock signal and outputting the same through an output terminal CLOCK; And an interface unit for outputting an additional signal for an interface for receiving the extracted FIC information and MSC information and the FIC information and MSC information through each output terminal to interface with another device.

The interface unit may include: an output terminal DATA to output the FIC information and the MSC information; An output terminal (FIC / MSC) for outputting a signal indicating which of the FIC information and the MSC information are being output from the output terminal DATA; An output terminal CIFSTART for outputting a signal indicating the start time of the CIF; An output terminal SCHSTART for outputting a signal indicating a start time of a sub channel; An output terminal SCHID for outputting a sub channel identifier ID; An output terminal VALID for outputting a signal indicating whether data currently output through the output terminal DATA is valid data; And a control unit for controlling a corresponding signal to be output through each of the output terminals.

The output terminals DATA, FIC / MSC, CIFSTART, SCHSTART, and VALID may be configured as one terminal, and the output terminal SCHID may be configured as six terminals. In this case, the controller may be configured to output a total of 13 bits of sub channel identifiers per sub channel by 6 bits through the six output terminals SCHID.

The interface unit may further include one output terminal SOP for outputting a signal indicating a start point of the transport stream TS.

In each embodiment of the DMB baseband receiver, the control unit receives an output selection signal for controlling an output state made through each output terminal, and outputs data to be output through each output terminal according to the output selection signal. May be configured to selectively control.

The output selection signal may include a signal Auto for outputting both the FIC information and MSC information, and a signal Manual for selectively outputting the signal.

The output selection signal includes a selection signal (FIC ON / OFF) for outputting the FIC information, the control unit outputs the FIC information through the output terminal DATA according to the selection signal (FIC ON / OFF) or It can be configured not to output.

The output selection signal includes a selection signal DAB / DMB for selecting audio / data and video, and the controller is configured to display audio / data information and video information among the MSC information according to the selection signal DAB / DMB. It may be configured to selectively output through the output terminal (DATA).

The output selection signal includes a selection signal SCHID_SEL that designates a subchannel identifier, and the controller outputs only information of a corresponding subchannel of the MSC information through the output terminal DATA according to the selection signal SCHID_SEL. It can be configured to.

On the other hand, the baseband processing unit, the channel separation unit for separating the FIC channel and the MSC channel by processing the DMB signal received through the antenna, the FIC processing unit for decoding the signal carried on the separated FIC channel, and the MSC channel It may be configured to include an MSC processing unit for processing the signal to output audio / data information and video information.

The baseband processor, the clock generator, and the interface unit may be configured to be embedded in a single integrated circuit chip.

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

First, the terrestrial DMB signal will be described. The DMB signal includes a fast information channel (FIC) part that informs about configuration and service information, and an MSC (main, audio, video, and data). Service Channel). Therefore, if the information contained in the FIC portion is decoded, the configuration information capable of decoding the information contained in the MSC portion can be known. That is, the number of channels transmitted from the MSC portion, the channel size, and the coding rate can be known through the decoding of the FIC information. Through this, the information of the MSC portion is decoded. In addition, the MSC portion is composed of a plurality of sub-channels (Sub Channel), up to 64 sub-channels can be included, each sub-channel has a unique identifier (ID). The sub channel identifier may be 0 to 63, and each sub channel may include data for informing audio, video, or other information.

Referring to FIG. 1, the DMB baseband receiver 10 according to the present invention includes a baseband processor 11, a clock generator 12, and an interface unit 13.

The baseband processor 11 receives the DMB signal, extracts the FIC information and the MSC information from the received DMB signal, and transfers the FIC information to the interface unit 13. In this case, the MSC information includes audio / data information and video information, and the interface unit 13 may receive other signals necessary for interfacing with other devices from the baseband processor 11.

The clock generator 12 generates and outputs a reference clock signal through the clock output terminal in order for the other device 91 to find a desired signal by using various interface signals output from the interface unit 13.

Meanwhile, the interface unit 13 transfers the FIC information and the MSC information extracted from the baseband processor 11 to another device. As described in detail below, the FIC information and the MSC information are one output terminal. It outputs through and, in addition, outputs various interface signals through various output terminals. That is, the interface unit 13 defines an independent output interface scheme of the DMB baseband receiver 10, and various audio decoders, video decoders, and other application devices that can be used in connection with the DMB baseband receiver 10 ( It is in charge of the interface with 91). In addition, the reference clock signal as described above is also included in the interface signal.

Referring to FIG. 2, a specific embodiment constituting the interface unit 13 will be described. The interface unit 13 is a control unit 22 that outputs a corresponding interface signal through various output terminals 21 and respective output terminals. Can be done.

The output terminal 21 outputs a signal for indicating whether the data currently being output is FIC information or MSC information through the output terminal DATA to output FIC information and MSC information, and the output terminal DATA. / MSC), the output terminal (CIFSTART) to output the signal to start the CIF (Common Interleaved Frame), the output terminal (SCHSTART) to output the signal to indicate the start of the sub-channel, the sub-channel identifier to output The output terminal SCHID may include an output terminal VALID for outputting a signal indicating whether data currently output through the output terminal DATA is valid data. The output terminal 21 is a position for connecting to an audio decoder, a video decoder, and other application devices, and there is also an output terminal CLOCK of a clock signal.

In addition, the output terminal 21 may be configured to further include an output terminal SOP for outputting a signal indicating a start time of a transport stream (TS).

The output terminal CLOCK, DATA, FIC / MSC, CIFSTART, SCHSTART, VALID, SOP, etc., the corresponding signal is output through one terminal, the output terminal SCHID may be composed of six terminals.

In addition, the controller 22 controls to output a corresponding signal through each output terminal.

Referring to FIG. 3, a specific example of the interface signal output from the interface unit 13 will be described. In the output terminals CLOCK, DATA, FIC / MSC, CIFSTART, SCHSTART, VALID, and SOP, one bit signal is output. In addition, when the sub channel identifier is configured to be output through six output terminals, a six bit signal is output from the output terminal SCHID.

The clock signal output from the output terminal CLOCK is for synchronization of output data, and the signal output from the output terminal FIC / MSC is whether the data output from the current output terminal DATA corresponds to the FIC information or the data corresponding to the MSC information. Indicates cognition. The signal output from the output terminal CIFSTART indicates the starting point of the CIF. CIF means a logical frame of the terrestrial DMB and corresponds to 24ms in time. The number of CIFs included in the MSC interval is determined according to the transmission mode (TM). In the case of the transmission mode I (TM I) used in Korea, one MSC interval is composed of four CIFs.

The signal output from the output terminal SCHSTART informs the start point of the sub channel. At this time, a maximum of 64 subchannels may be included in one CIF, and data corresponding to each subchannel should be distinguished from each other because it includes independent information. Therefore, the starting point of the subchannel should be indicated.

The signal output from the output terminal SCHID indicates a sub channel ID. Since the sub channel identifier may have a number from 0 to 63, a total of 6 bits are used. The signal output from the output terminal SCHID further includes the size of the currently output subchannel. Since the maximum size of one subchannel is 43,776 bits (EEP, Set B), 16 bits are required to express it, but all subchannel sizes may be configured to be represented by 13 bits considering the multiple of 8. As shown, the first subchannel identifier value (sch_id [5: 0]) of the signal output from the output terminal SCHSTART represents the identifier of the corresponding subchannel, and the subchannel size (sch_size) for the next three clocks. At this time, after the information on the last sub-channel size is output, it can be filled with an arbitrary value until the corresponding sub-channel ends.

The signal output from the output terminal VALID indicates that the signal output from the current output terminal DATA is valid data.

The signal output from the output terminal SOP (Start of Packet) indicates the start time of the transport stream (TS) packet. Since the start value of the transport stream packet always consists of the hexadecimal '47', the output terminal DATA because the hexadecimal '47' can be detected by other devices that need it if the signal is not serviced. If the signal output from the DMB data can be configured to indicate the start of the transport stream packet.

Referring to FIG. 4, the control unit 22 constituting the interface unit 13 receives an output selection signal for allowing a user to select an output type, and outputs data through each output terminal according to the input output selection signal. May be configured to selectively control. For example, only the FIC information may be controlled to be output, and it may be configured in various ways as needed, such as controlling to output only a desired subchannel among various subchannels.

The output selection signal may be transmitted from another device 91 such as an audio / video decoder or other application device 91. That is, it is possible to add convenience to the use of other devices that interface with the DMB baseband receiver 10.

Specific examples of the output selection signal for the purpose of understanding the description include a signal for outputting both FIC information and MSC information through the output terminal DATA (Auto), a signal for selectively outputting (Manual) and FIC information. Selector signal (FIC ON / OFF), audio / data information or video information for selecting and outputting (DAB / DMB), and subchannel identifier for outputting only specific subchannel information. It may be configured to include a selection signal (SCHID_SEL) and the like.

Then, the controller 22 controls the signals to be output through each output terminal according to the output selection signal.

Referring to FIG. 5A, when the Auto signal is input, the controller 22 controls the corresponding signal to be output through all output terminals (S51-1 and S51-2). In particular, when the DAB / DMB selection signal is input, The audio / data information or the video data is selectively output through the output terminal DATA according to the selection signal (S51-1, S51-3).

Referring to FIG. 5B, when a manual signal is input, the controller 22 may determine an output according to the FIC ON / OFF signal and the SCHID_SEL signal. That is, when the FIC ON signal is input, the FIC information is output (S52-1, S52-2). When the FIC OFF signal is input, the FIC information is not output (S52-3). In addition, when a subchannel identifier is input through the SCHID_SEL signal (S52-4), if a subchannel having the corresponding subchannel identifier is included in the MSC information, only information on the subchannel is output (S52-5, S52-). 6).

In addition, when the corresponding subchannel identifier is not selected while the FIC ON signal is input, only the FIC information may be output. In this case, the signals of the output terminals CIFSTART, SCHSTART, and SCHID will be meaningless signals and can be controlled to output a logic value '0'. In addition, when the FIC OFF signal is input, only data corresponding to the subchannel identifier selected by the SCHID_SEL signal may be output, and audio / data information or video information may be selectively output according to the DAB / DMB selection signal. As such, the type of output selection signal and its processing may be variously configured.

In each of the embodiments described above, the baseband processing unit 11, the clock generator 12, and the interface unit 13 of the DMB baseband receiver 10 according to the present invention are configured in the form of a single integrated circuit chip. Can be.

An embodiment of configuring the baseband processor 11 of the DMB baseband receiver will be described with reference to FIG. 6.

The baseband processor 11 processes the DMB signal received through the antenna to separate the FIC channel and the MSC channel, and the information on the FIC channel separated by the channel separator 11-1 and the channel separator 11-1. And an MSC processing unit 11-3 for processing audio signals and outputting audio / data information and video information by processing a signal carried on the MSC channel.

A specific embodiment of the baseband processor 11 will be described with reference to FIG. 7.

First, the DMB signal received through the antenna 70 in the channel separator 11-1 is converted into a pass-band signal of a desired intermediate frequency through the tuner 71-1. Automatic gain controller (71-2, AGC) serves to keep the size of the signal input to the A / D converter (71-3) constant, and serves to multiply the gain value calculated according to the reference signal size. do. Therefore, the A / D converter 71-3 performs sampling to transform the digital signal regardless of the magnitude of the received signal. The mode detector 71-4 detects a transmission mode of the received signal, and the I / Q divider 71-5 restores a real part of the received complex signal to a complex signal.

The OFDM demodulator 71-7 removes unnecessary guard intervals and converts the signal in the time domain into the frequency domain through fast fourier transform (FFT). The signal synchronizer 71-6 extracts information necessary for synchronization in the time / frequency domain of the signal using the input and output signals of the OFDM demodulator 71-7. The frequency deinterleaving unit 71-8 restores the positions of the sub-carrier signals interleaved by the transmitter, and the channel divider 71-9 controls the FIC channel and the data channel. Isolate the MSC channel.

The FIC decoder 72 receives the FIC channel signal and extracts information necessary to decode the MSC channel.

Meanwhile, the time deinterleaving unit 73-1 in the MSC processing unit 11-3 restores the 16 logical frames interleaved by the transmitter in the original frame order. The time deinterleaved MSC channel corrects a random error occurring in the transport channel through a convolutional decoder (73-2). The data whose error is corrected is energy descrambled through the energy descrambler 73-3 and restored to the original data.

The channel divider 73-4 distinguishes and separates whether the transmitted MSC channel is a data / audio signal for a DAB service or a video signal for a DMB service. At this time, the MSC channel is composed of Common Interleaved Frame (CIF), and the smallest unit that can be assigned an address in the CIF is a Capacity Unit (CU), and one CU is 64-bit. The MSC channel is a multiple structure of these subchannels because such a plurality of CUs are connected to form one subchannel. The interface unit 13 outputs each interface signal through the corresponding output terminal according to this structure.

On the other hand, the signal for the DMB service is again input to the convolutional deinterleaving (73-5). The convolutional deinterleaving unit 73-5 rearranges the data additionally interleaved by the transmitter in the original order, and the RS decoder 73-6 restores the RS encoded data by the transmitter. At this time, a transport stream (TS) packet is output from the RS decoder 73-6.

As described above, the DMB baseband receiver provides a new interface with a video decoder, audio decoder, or other application device. Accordingly, it is possible to flexibly interface with various devices using baseband-processed FIC information and MSC information, and to apply and develop various devices related to DMB.

Claims (12)

A baseband processor configured to receive the DMB signal and extract FIC information and MSC information; A clock generator generating a reference clock signal and outputting the same through an output terminal CLOCK; And And an interface unit for outputting the FIC information and the MSC information extracted by the baseband processor and the interface additional signal for receiving the FIC information and the MSC information through each output terminal to interface with other devices. Done, The interface unit, An output terminal DATA for outputting the FIC information and the MSC information; An output terminal (FIC / MSC) for outputting a signal indicating which of the FIC information and the MSC information are being output from the output terminal DATA; An output terminal CIFSTART for outputting a signal indicating the start time of the CIF; An output terminal SCHSTART for outputting a signal indicating a start time of a sub channel; An output terminal SCHID for outputting a sub channel identifier ID; An output terminal VALID for outputting a signal indicating whether data currently output through the output terminal DATA is valid data; And And a control unit for controlling a corresponding signal to be output through each of the output terminals. delete The method of claim 1, The output terminal DATA, FIC / MSC, CIFSTART, SCHSTART, and VALID is composed of one terminal, and the output terminal SCHID is composed of six terminals. The method of claim 3, wherein And the control unit is configured to output subchannel size information of a total of 13 bits per subchannel by 6 bits in order over 3 clocks through the six output terminals SCHIDs. The method of claim 1, The interface unit may further include one output terminal SOP for outputting a signal indicating a start point of the transport stream TS, and the controller may output the corresponding signal through the output terminal SOP. DMB baseband receiver. The method of claim 1, And the control unit is configured to receive an output selection signal and to selectively control data to be output through the respective output terminals according to the output selection signal. The method of claim 6, The output selection signal includes a signal (Auto) for outputting both the FIC information and MSC information through the output terminal DATA and a signal (Manual) for selectively outputting the DMB baseband receiver. The method of claim 7, wherein The output selection signal further includes a selection signal (FIC ON / OFF) for outputting the FIC information, and the controller outputs the FIC information through the output terminal DATA according to the selection signal (FIC ON / OFF). DMB baseband receiver, characterized in that configured not to output. The method of claim 7, wherein The output selection signal includes a selection signal DAB / DMB for selecting audio / data and video, and the controller is configured to display audio / data information and video information among the MSC information according to the selection signal DAB / DMB. DMB baseband receiver, characterized in that configured to selectively output through the output terminal (DATA). The method of claim 7, wherein The output selection signal further includes a selection signal SCHID_SEL for designating a sub channel identifier, and the controller outputs only the corresponding sub channel information among the MSC information through the output terminal DATA according to the selection signal SCHID_SEL. And a DMB baseband receiver. The method of claim 1, The baseband processing unit, a channel separation unit for processing the DMB signal received through the antenna to separate the FIC channel and the MSC channel, the FIC processing unit for decoding the signal carried on the separated FIC channel, and the signal carried on the MSC channel And an MSC processor for processing the audio / data information and video information. The method of claim 1, The baseband processing unit, the clock generator, and the interface unit DMB baseband receiver, characterized in that the configuration is built in a single integrated circuit chip (IC Chip).

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