KR20080049494A - DMB Baseband Receiver - Google Patents

Abstract

The present invention performs baseband processing to receive digital multimedia broadcasting (DMB) to extract fast information channel (FIC) information and main service channel (MSC) information, and add header information to the extracted FIC information and MSC information. A new interface structure for output allows interoperability with audio / video decoders and other application devices. Accordingly, it is possible to flexibly interface with various devices using the FIC information and the MSC information of the DMB, thereby enabling the development and application of various devices related to the DMB.

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 illustrates an embodiment of configuring header information;

5 is an embodiment of configuring a control unit;

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

7 is an embodiment of a baseband processor;

8 is a detailed embodiment of the baseband processor.

* Explanation of symbols for main parts of the drawings

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

The present invention relates to a DMB baseband receiver. In particular, the present invention relates to a digital multimedia broadcasting (DMB), performs baseband processing to extract FIC information and MSC information, and adds header information to the extracted FIC information and MSC information. According to the new interface method, it can be linked with various audio / video decoders and other application devices.

Digitalization of broadcasts has also affected analog radio broadcasts, speeding up the advent of the digital radio broadcast era. 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, the baseband processing to extract the FIC information and MSC information by receiving the DMB signal, and adds the header information to the extracted FIC information and MSC information to output Its purpose is to provide a DMB baseband receiver that can interoperate with various audio decoders, video decoders, and many other application devices through a new interface method.

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 a clock output terminal CLOCK; And an interface unit for adding header information to the FIC information and the MSC information, and outputting the FIC information, the MSC information, and the interface additional signal to which the header information is added, through each output terminal to interface with other devices. Is done.

The interface unit may include: an output terminal DATA to output FIC information and MSC information to which the header information is added; An output terminal VALID for outputting a signal indicating whether data currently output through the output terminal DATA is valid data; And a controller configured to add header information to the FIC information and the MSC information extracted by the baseband processor and to control a corresponding signal to be output through the respective output terminals.

The output terminals CLOCK, DATA, and VALID may be configured as one terminal.

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 be configured to output a corresponding signal through the output terminal SOP. .

The header information added to the FIC information and the MSC information may include a field indicating whether the corresponding data is FIC information or MSC information.

The header information may have a 32-bit size, and the field indicating whether the corresponding data is FIC information or MSC information may have a 1-bit size.

Header information added to the MSC information may be added in units of subchannels.

The header information added to the MSC information may include a field for indicating a subchannel identifier, a subchannel size, a CIF start time, and a subchannel start time.

The clock generator may be configured to selectively output a clock signal having any one of a plurality of clock frequencies according to a clock control signal. In this case, the plurality of clock frequencies may be configured to include Masked 4.096MHz and Fixed 6.144MHz.

In each of the above embodiments, the controller may be configured to receive an output selection signal and to selectively control data to be output through the output terminal DATA according to the output selection signal.

The output selection signal may include a signal Auto for outputting both FIC information and MSC information to which header information is added through the output terminal DATA, and a signal Manual for selectively outputting the signal.

The output selection signal may further include a selection signal (FIC ON / OFF) for outputting FIC information together with the manual signal, and the control unit may include header information in the FIC information according to the selection signals Manual and FIC ON / OFF. It may be configured to determine whether to output through the output terminal DATA by adding a.

The output selection signal includes a selection signal (DAB / DMB) for selecting audio / data and video, and the controller controls header information on audio / data information or video information among the MSC information according to the selection signal DAB / DMB. In addition, it may be configured to output through the output terminal (DATA).

The output selection signal further includes a selection signal (SCHID_SEL) for designating a sub channel identifier, and the control unit adds header information of only subchannel information among the MSC information according to the selection signal SCHID_SEL to add the header information to the output terminal ( Data).

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 It may be configured to include an MSC processing unit for processing to output the 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 data configuration and service information, and an MSC (including actual audio, video, and data). Main 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 exist from 0 to 63, and each sub channel may include data for indicating 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. At this time, the MSC information includes audio / data information and video information.

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

The interface unit 13 transfers the FIC information and the MSC information extracted from the baseband processor 11 to another device 91. In particular, the interface unit 13 adds header information to the FIC information and the MSC information, and adds the header. FIC information and MSC information with the added information are output through one output terminal.

In addition, an interface additional signal is output through each output terminal. That is, the interface unit 13 defines the output interface method of the DMB baseband receiver 10, and other devices such as various audio decoders, video decoders, and other application devices that can be used by being connected to the DMB baseband receiver 10. It is in charge of the interface with 91.

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 an interface signal through various output terminals 21 and respective output terminals. Can be done.

The output terminal 21 is a part for connecting with an audio decoder, a video decoder, and other application devices 91. As the output terminal 21, an output terminal for outputting a signal indicating whether the data currently output through the output terminal DATA to output FIC information and MSC information to which header information is added and the output terminal DATA is valid data ( VALID), and there is also an output terminal CLOCK for outputting a reference clock signal generated by the clock generator 12.

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

At this time, the output terminals CLOCK, DATA, VALID, SOP, etc. consist of one terminal.

The controller 22 controls to output a corresponding signal through each output terminal.

In detail, an interface signal output from each output terminal will be described with reference to FIG. 3. In an embodiment in which the output terminals CLOCK, DATA, VALID, and SOP exist, the output signals may be configured as a total of 4 bits.

The clock signal output from the output terminal CLOCK is for synchronization of output data, and the signal output from the output terminal VALID indicates that the signal output from the current output terminal DATA is valid data. At this time, the output of valid data can be configured to burst so that the signal at the output terminal VALID changes constantly.

Meanwhile, a unit of a logical frame of the terrestrial DMB includes a common interleaved frame (CIF), and up to 64 subchannels may be included in one CIF. As long as the channel configuration information does not change, the data transmission amount of one CIF is constant, so that a burst-configured VALID signal may also be configured in CIF units.

In addition, the signal output from the output terminal SOP (Start of Packet) indicates the start time of the transport stream packet (TS Packet). Since the start point of a transport stream packet is always composed of hexadecimal '47', if it is not serviced, it is troublesome to detect hexadecimal '47' from another device that needs it. If the data is DMB data, it can be configured to indicate the start point of the transport stream packet.

On the other hand, the data output from the output terminal DATA is the FIC information or MSC information to which the header information (H) is added as described above, the content or size of the header information can be configured in various ways as needed. An embodiment of configuring 32-bit header information added to FIC information or MSC information will be described with reference to FIG. 4.

As shown in the example of FIGS. 4A and 4B, the header information may include a field (fic / msc) indicating whether the corresponding data is FIC information or MSC information, and whether the data following the header information is FIC information. Alternatively, one bit size can be allocated because it can be identified as MSC information. That is, if the logical value of this field is '0' (or '1'), it may indicate FIC information, and if '1' (or '0'), it may indicate MSC information.

Header information added to the MSC information may be configured to be added in units of subchannels. That is, header information can be pasted and output for each subchannel. In this embodiment, the header information may include a sub channel identifier field (schid: Sub Channel ID), a sub channel size field (schsize), a field indicating a CIF start time (cifstart), in addition to the field fic / msc as shown in the example shown in FIG. It may be configured to include a field (schstart) for indicating the sub-channel start time. In addition, other contents indicating the contents of the sub channel may be included.

In FIG. 4, numbers in parentheses indicate the number of bits constituting each field. For example, since the subchannel identifier may have a number from 0 to 63, 6 bits may be allocated to the subchannel identifier field (schid). When the maximum size of one subchannel is 43,776 bits (EEP, Set B), 16 bits may be allocated to the subchannel size field (schsize).

Such header information is started to be output through the output terminal DATA at the start time of each sub-channel indicated by the output signal of the output terminal VALID and the start time at which the FIC information is output as shown in the example shown in FIG. ) Is output first, followed by sub-channel data or FIC data.

Meanwhile, the clock generator may be configured to selectively output a clock signal having any one of a plurality of clock frequencies according to the clock control signal. As one example, it may be configured to output one of the clock signal according to the clock control signal of Masked 4.096MHz and Fixed 6.144MHz.

Referring to FIG. 5, the controller 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, it can be controlled to output only FIC information, or can be controlled to output only desired subchannels among the subchannels.

This function opens the possibility to implement more convenient and various functions to other devices 91 that work with the DMB baseband receiver 10. Therefore, the output selection signal may be configured to be transmitted from another device 91 such as an audio decoder, a video decoder, or another application device that wants to use information output from the output terminal of the DMB baseband receiver 10.

At this time, regardless of the type of output selected, the output of meaningful data through the output terminal DATA can be configured to burst, and the meaningful data output through the output terminal DATA always includes header information. do.

As a specific example of the output selection signal, a signal (Auto) for outputting both FIC information and MSC information added with header information, a signal for selectively activating a signal (Manual), and whether to output FIC information (FIC ON / OFF), audio / data or video selection signal (DAB / DMB), subchannel identifier 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. 6A, when the auto signal is input, the controller 22 controls the output terminal DATA to output both the FIC information and the MSC information (S61-1, S61-2). In particular, the DAB / DMB selection signal is input. In this case, audio / data information or video data is selectively output through the output terminal DATA according to the selection signal (S61-1, S61-3).

Referring to FIG. 6B, 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 (S62-1, S62-2). When the FIC OFF signal is input, the FIC information is not output (S62-3). In addition, when a subchannel identifier is input through the SCHID_SEL signal (S62-4), if the subchannel having the corresponding subchannel identifier is included in the MSC information, only information on the subchannel is output (S62-5, S62-). 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, fields other than the field fic / msc included in the header information will be meaningless fields and can be set to any logical value. 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 DAB or DMB data 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. 7.

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.

An exemplary embodiment of the baseband processor 11 will be described with reference to FIG. 8.

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 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 generates header information according to this structure and adds the header information to the FIC information and the MSC information.

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 according to the present invention provides a new interface structure with a video decoder, audio decoder, or other application device. In particular, the interface structure is very simple because only three outputs (four outputs when SOP is added) can be interfaced. In addition, the reference clock signal can be selected from a variety of clock signals (e.g., Masked 4.096Mhz, Fixed 6.144Mhz) to enhance convenience when using the final output.

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 (17)

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 The header information is added to the FIC information and the MSC information extracted by the baseband processor, and the FIC information, the MSC information, and the interface additional signal to which the header information is added are output through each output terminal so as to interface with other devices. DMB baseband receiver comprising an interface unit. The method of claim 1, The interface unit may include: an output terminal DATA to output FIC information and MSC information to which the header information is added; 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 configured to add header information to the FIC information and the MSC information extracted by the baseband processing unit, and to control a corresponding signal to be output through the respective output terminals. The method of claim 2, The output terminal DATA and VALID is a DMB baseband receiver, characterized in that composed of one terminal. The method of claim 3, wherein 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, The header information added to the FIC information and the MSC information includes a field indicating whether the corresponding data is FIC information or MSC information. The method of claim 5, wherein The header information has a 32-bit size, and the field indicating whether the FIC information or MSC information comprises a 1-bit size DMB baseband receiver. The method of claim 5, wherein The header information added to the MSC information is configured to be added in units of subchannels. The method of claim 7, wherein The header information added to the MSC information includes a field for indicating a subchannel identifier, a subchannel size, a CIF start time, and a subchannel start time. The method of claim 1, And the clock generator is configured to selectively output a clock signal having any one of a plurality of clock frequencies according to a clock control signal. The method of claim 9, The plurality of clock frequencies are masked 4.096MHz and fixed 6.144MHz DMB baseband receiver characterized in that it is configured. The method according to any one of claims 2 to 10, And the control unit is configured to receive an output selection signal and to selectively control data to be output through the output terminal DATA according to the output selection signal. The method of claim 11, The output selection signal includes a signal Auto for outputting both FIC information and MSC information to which header information is added through the output terminal DATA, and a signal Manual for selectively outputting the DMB. Baseband Receiver. The method of claim 12, The output selection signal further includes a selection signal (FIC ON / OFF) for outputting FIC information together with the manual signal. And the control unit is configured to determine whether to output through the output terminal DATA by adding header information to the FIC information according to the selection signal Manual and FIC ON / OFF. The method of claim 11, The output selection signal further includes a selection signal (DAB / DMB) for selecting audio / data and video, and the controller controls audio / data information or video information among the MSC information according to the selection signal 'DAB / DMB'. DMB baseband receiver, characterized in that configured to add the header information and output through the output terminal (DATA). The method of claim 11, The output selection signal further includes a selection signal (SCHID_SEL) for designating a sub channel identifier, and the controller adds header information of only the corresponding sub channel information of the MSC information according to the selection signal 'SCHID_SEL' to output the output terminal ( DMB baseband receiver, characterized in that configured to output through. The method according to any one of claims 1 to 10, 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 according to any one of claims 1 to 10, 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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