KR20060091581A - Apparatus and method of channel decoding in digital multimedia broadcasting a receiving set - Google Patents

Abstract

The present invention relates to a digital multimedia broadcasting receiver. After demodulating a received signal, the demodulated signal is divided into a quick information channel (FIC) and a main service channel (MSC), and the information on the quick information channel (FIC). Transmitting a signal to allow a user to select a sub-channel desired for decoding in the main service channel; And a step S2 of correcting, decoding, and displaying only sub-channels of the user selected main service channel (MSC).

Therefore, according to the present invention, it is possible to decode only a subchannel desired by a user among transmitted subchannels, thereby reducing power consumption and increasing efficiency.

Quick information channel, main service channel

Description

Apparatus and Method of Channel Decoding in Digital Multimedia Broadcasting a receiving set}

1 is a conceptual block diagram of a digital multimedia broadcasting receiver including the present invention.

2 is a diagram showing the structure of a transmission frame for digital multimedia broadcasting in accordance with the present invention.

3 is a conceptual block diagram for decoding only a main service channel desired by a user according to the present invention.

4 is a configuration block diagram for partial primary service channel decoding according to the present invention.

5 is a diagram showing the output of each component block diagram according to the present invention;

6 is a flowchart illustrating a partial main service channel decoding process in a digital multimedia broadcasting receiver according to the present invention.

* Explanation of symbols for the main parts of the drawings

201: tuner 202: OFDM demodulator

203: channel decoder 204: user controller

205: Audio / Video Decoder 401: Block Aggregator

402: time reverse interleaver 403: memory

404: Collector 405: Weaving Decoder

406: energy reverse scrambler

The present invention relates to a digital multimedia broadcasting receiver, and more particularly, to a method for reducing power consumption by decoding only a desired channel among received broadcast channels.

Digitization of broadcasts has also affected conventional analog radio broadcasts, speeding up the advent of digital radio broadcasts. In addition to the conventional voice radio service, digital multimedia broadcasting (Digital Multimedia Broadcasting) that includes data transmission and multimedia services has become possible.

The digital multimedia broadcasting is robust against noise and distortion on a transmission channel, has a high transmission efficiency, and has various advantages of enabling various multimedia services.

Terrestrial digital multimedia broadcasting among the digital multimedia broadcasting is a RS code that is robust to burst errors that may occur on a transmission channel in order to improve multimedia broadcasting performance based on digital audio broadcasting in Europe. Added Solomon Code and Convolutional Interleaver.

The two additional parts are applied to the digital radio broadcast ensemble input signal at the transmitter, and provide an error rate low enough to enable video service even in a mobile reception environment.

However, the transmission channel of the digital multimedia broadcasting is a wireless mobile reception channel, and the amplitude of the received signal is not only time-varied, but also the Doppler spread of the received signal spectrum due to the influence of the mobile receiver. Doppler Spreading) occurs.

In consideration of the transmission and reception in such a channel environment, the digital multimedia broadcasting transmission method is based on Orthogonal Frequency Division Multiplexing (OFDM).

In addition, interleaving is performed in the time domain and the frequency domain, so that an error occurring in the transmission channel can be corrected at the receiving end.

The above-described digital multimedia broadcasting transmission signal is transmitted with a much smaller signal strength than the conventional analog radio broadcasting signal, and considering the mobile reception environment such as a vehicle in a severe fading channel environment such as a city, the actual reception signal The century is very small.

Accordingly, the digital multimedia broadcasting receiver should be able to receive the received signal as much as possible in such a poor reception environment and correct an error that may occur in the transmission process.

In addition, considering the fact that it is a mobile receiver, the maximum reception performance at a limited cost is a key requirement of the digital multimedia broadcasting receiver.

The conventional digital multimedia broadcasting receiver decodes all the transmitted channels. In the real audio / video decoder, only one channel selected by the user is displayed by decoding from all the transmitted channels. There was a problem that the efficiency is low and the efficiency is low due to the high power consumption.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and in the present invention, the purpose of the present invention is not to decode all of the received broadcast channels, but to increase efficiency by decoding only a channel desired by the user, and to reduce power consumption of the reception apparatus. .

In order to achieve the above object, the present invention demodulates a received signal and separates the demodulated signal into a fast information channel (FIC) and a main service channel (MSC), and the quick information channel. Transmitting information on the (FIC) to allow a user to select a sub-channel to decode in the primary service channel; And a step S2 of correcting, decoding, and displaying only sub-channels of a user selected main service channel (MSC).

In the step S1, the selection is characterized by receiving the ID of each subchannel from the information on the fast information channel transmitted and selecting a subchannel ID desired for decoding.

In step S2, time deinterleaving, convolutional decoding, energy descrambling, and RS decoding are performed only on the main service channel corresponding to the sub channel ID selected and transmitted by the user.

According to still another embodiment of the present invention, the present invention passes through an OFDM demodulator for demodulating a received signal, and transmits information on a quick information channel among the demodulated signals to a user control unit in a sub-channel selected and transmitted by a user. A channel decoder to decode And a user controller for selecting an ID of a subchannel to be decoded from the information on the fast information channel received from the channel decoder and transmitting the ID to the channel decoder. to provide.

The channel decoder includes a block aggregater for separating the demodulated signal transmitted in OFDM symbol units into a fast information channel and a primary service channel signal; A time inverse interleaver which receives a sub channel ID from the user controller and deinterleaves only a selected sub channel among the main service channels; An aggregater for muxing the fast information channel and the deinterleaved subchannel; A convolutional decoder that convolutionally decodes the coarse signal and performs error correction; And an energy inverse scrambler for decoding the error corrected signal into an original signal.

The user controller may serve as an interface with the channel decoder to decode only a subchannel desired by a user.

The same components as in the prior art are given the same names and the same reference numerals for convenience of description, and detailed description thereof will be omitted.

The digital multimedia broadcasting receiver including the channel decoder according to the present invention configured as described above will be described with reference to the accompanying drawings.

Digital multimedia broadcasting is configured to maximize reception performance even in a mobile environment. To this end, a coded orthogonal division multiplexing (COFDM) is used as a transmission method. This is a method of transmitting desired information on a network.

When the information is carried and transmitted by the COFDM scheme, it has better characteristics in signal distortion due to multi-path and inter-symbol interference than the single carrier scheme.

In addition, in order to further increase reception performance, the channel encoder performs RS encoding with excellent block correction capability, convolutional encoding with random error correction capability in each subchannel unit, and performs time domain interleaving.

The time domain interleaving refers to mixing data in the time domain in order to minimize errors that may occur during transmission. It then interleaves again in the frequency domain.

The purpose of the interleaving in the time domain and the frequency domain is to minimize errors when decoding real data during decoding by randomizing an error of a signal input to a receiving apparatus.

Hereinafter, a decoding method in a digital multimedia broadcasting receiver according to the present invention will be described with reference to the accompanying drawings.

First, FIG. 1 is a conceptual block diagram of a digital multimedia broadcasting receiver including the present invention.

The signal input to the antenna 100 of the receiver is converted into a pass-band signal of a desired intermediate frequency via the tuner 101.

The automatic gain control unit 102 multiplies the gain value calculated according to the magnitude of the reference signal to keep the magnitude of the signal input to the A / D 103 constant.

The A / D 103 converts an analog signal into a digital signal by performing sampling regardless of the magnitude of the received signal.

The I / Q divider 104 converts the baseband to a baseband using a real part of a received complex signal.

The mode detector 105 detects a transmission mode of the received signal.

The signal synchronizer 106 extracts information necessary for synchronization in the time / frequency domain of the signal using the input and output signals of the OFDM demodulator.

The OFDM demodulator 107 removes unnecessary guard intervals and then converts a signal in the time domain into a signal in the frequency domain through fast fourier transform (FFT).

The frequency deinterleaver 108 deinterleaves the positions of the subcarrier signals interleaved and transmitted by the transmitter and restores them.

The block aggregator 109 functions as a demux for separating signals input in units of OFDM symbols into a fast information channel as a control channel and a main service channel as a data channel.

The fast information channel decoder 110 receives the fast information channel among the signals output from the block aggregater 109, performs convolutional decoding and energy descramble, and extracts information necessary to decode the main service channel.

The time deinterleaver 111 deinterleaves the frames of the 16 logical primary service channels interleaved and transmitted by the transmitter to restore the original frame order.

The convolutional decoder 112 corrects random errors that may occur during transmission of the time deinterleaved main service channel.

The energy descrambler 113 restores error corrected data to original data.

The channel distributor 114 has a demux function for distinguishing and separating the audio / data signal for the digital audio broadcasting service and the video signal for the digital multimedia broadcasting service among the main service channels transmitted through the error correction and the original data. do.

The convolutional deinterleaver 115 receives the separated video signal through the channel distributor 114 for the digital multimedia broadcasting service, and rearranges the data additionally interleaved by the transmitter in the original order.

The RS decoder 116 performs error correction on data transmitted by RS encoding at a transmitting end.

The quick information channel data decoder 117 restores separate data transmitted through the quick information channel.

The audio / data decoder 118 receives and decodes the audio / data signals transmitted separately through the channel distributor 114 for the digital audio broadcasting service.

The video decoder 119 receives and decodes the video signal transmitted through the channel divider 114.

The audio / data decoder 118 and the video decoder 119 classify and decode audio / data and video signals under the control of the fast information channel data decoder 117, respectively.

2 is a view showing the structure of a transmission frame of a digital multimedia broadcasting according to the present invention. The transport frame consists of a synchronization channel, a quick information channel, and a primary service channel.

However, in the above-described synchronization channel, only the fast information channel (FIC) and the main service channel (MSC) are transmitted to the forward error correction encoder for real error correction.

The quick information channel (FIC) is a channel transmitted without time interleaving by a transmitter, and has information for controlling a main service channel (MSC) having data to be actually decoded, and the quick information channel (FIC). Has a fast information block (FIB) as a component.

The main service channel (MSC) is a channel transmitted through time interleaving by a transmitter, and is composed of audio / video / data information which is data to be actually decoded. The main service channel (MSC) is a common interleaved frame (CIF). Is a component.

The organization and length of the above-described transmission frame depend on the transmission mode, and the transmission mode is I to IV.

Looking at the general transmission characteristics of these transmission frames through a table,

Transmission mode Duration of transmission frame FIB Number of Transmission Frames CIF number of transmission frame Transmission mode Ⅰ 96 ㎳ 12 4 Transmission mode Ⅱ 24 ㎳ 3 One Transmission mode Ⅲ 24 ㎳ 4 One Transmission mode Ⅳ 48 ㎳ 6 2

Same as

2 illustrates the transmission mode I shown in Table 1 as an example.

In Table 1, the transmission mode I has four CIFs constituting the main service channel (MSC). However, the digital multimedia broadcasting receiver currently under development allows up to 64 channels per CIF.

In the above, CIF is the serial digital output of the primary service mux containing the primary service channel portion of the transmission frame.

In addition, the CIF includes 864 CUs and is common to all transmission modes, and the CIF includes subchannels and paddings, each of which has a CU address.

The CU address is an address constituting a CIF, and the one CIF is composed of 864 CUs.

In the above description, a CU (capacity unit) is one unit constituting the CU address.

Since padding is a null concept, it is not necessary to fill a single CIF. Therefore, the CIF is composed of the subchannels and all remaining CU address parts are treated as padding. As shown in FIG. 2, the padding may be located at the last part, but may also be located between the subchannel and the subchannel.

In FIG. 2, three subchannels and paddings are configured to subchannels 0 to 2, and each subchannel has a CU address for each channel data, and each subchannel needs to have an address of the same length. none.

Referring to a conceptual block diagram for implementing a method for decoding only a sub-channel desired by a user according to the present invention, FIG. 3 is a conceptual configuration for decoding only a main service channel (MSC) desired by a user according to the present invention. It is a block diagram.

Referring to the decoding process of FIG. 3, first, a signal received through an antenna is removed by an OFDM demodulator 202 through a tuner 201 and then converted into a signal in a frequency domain through an FFT.

The signal converted by the OFDM demodulator 202 is input to the channel decoder 203 to decode a partial main service channel (Partial MSC). For this purpose, the channel decoder 203 is transmitted by the OFDM demodulator 202. The information on the fast information channel (FIC) of the received signal is transmitted to the user control unit 205.

The user controller 205 transmits the ID of the subchannel to be decoded from the received information on the fast information channel (FIC) to the channel decoder 203 again.

The channel decoder 203 receiving the ID of the user-selected subchannel decodes only the subchannel desired by the user among the main service channels, and transmits the decoded subchannel to the audio / video decoder. Now, only the desired subchannel is finally displayed.

The user controller 205 refers to a configuration block that serves as an interface with a channel decoder to decode only a channel desired by a user such as a computer, a cpu, and the like.

The portion corresponding to the channel decoder 203 collectively refers to the audio / data decoder 118 and the video decoder 119 after the block aggregater 109 of FIG.

Referring now to the detailed operation of the channel decoder 203, FIG. 4 is a block diagram illustrating a partial main service channel decoding according to the present invention.

The block diagram includes a block aggregater 401, a time deinterleaver 402, a memory 403, an aggregate 404, a convolutional decoder 405, and an energy descrambler 406.

An apparatus for decoding only a sub-channel desired by a user among the received main service channels will be described.

The block aggregator 401 functions as a demux for separately transmitting a fast information channel (FIC) and a primary service channel (MSC) among signals received through the OFDM decoder.

Since the fast information channel (FIC) of the separated signals is transmitted without time interleaving at the transmitter, the receiver is transmitted directly to the aggregator 404 without passing through the time deinterleaver 402.

However, since the main service channel (MSC) of the separated signals was transmitted by time interleaving at the transmitter, the receiver deinterleaves only the sub-channel selected by the user through the time deinterleaver 402 to decode it. It is then sent to aggregator 404.

The memory 403 is required for reverse interleaving in the time reverse interleaver 402, and the memory 403 uses a general SRAM, which is necessary for storing data other than the part for reverse interleaving during time reverse interleaving. Do.

Through the above-described process, the quick information channel (FIC) and the main service channel (MSC) are input to the aggregator 404, and the fast information channel (FIC) and the main service channel (MSC) are input from the aggregator 404. This function muxes the sub channel selected by the user.

The mux signal from the aggregator 404 is transmitted to the audio / video decoder through the convolutional decoder 405 and the energy descrambler 406 so that only the sub-channel selected by the user among the main service channels is displayed.

Looking at the output of each step in Figure 4, Figure 5 is a view showing the output of each component block according to the present invention.

First, the output of the block aggregator 401 is in the received state of the receiving device. That is, it has both a fast information channel (FIC) and a main service channel (MSC) and transmits them separately.

Only the main service channel (MSC) signal of the transmitted signals is input to the time inverse interleaver 402, and the time inverse interleaver 402 is controlled only by the user control unit 205 of FIG. Reverse interleaving is sent to the aggregate 404.

Thus, as shown in FIG. 5, the output from the time deinterleaver 402 is padded by all remaining subchannels, and only the desired subchannels are deinterleaved.

Then, after passing through the convolutional decoder 405 and the energy descrambler 406 through the aggregate 404 again, the output is output by the user of the fast information channel (FIC) and the main service channel as shown in the last part of FIG. It consists only of the desired subchannels.

6 is a flowchart illustrating a decoding method in the above-described receiving apparatus, and FIG. 6 is a flowchart illustrating a partial service channel decoding process in the digital multimedia broadcasting receiving apparatus according to the present invention.

First, the signal received through the antenna 100 of the receiver is demodulated by the OFDM demodulator 107 (step S10).

The demodulated signal input in units of OFDM symbols is demuxed into a fast information channel (FIC) and a main service channel (MSC) signal by the block aggregater 109 in the channel decoder 203 (step S20).

Information on the fast information channel (FIC) of the separated signal is transmitted to the user control unit 204 (step S30).

The user control unit 204 selects an ID of a subchannel to which the user wants to decode from among the main service channels in the transmitted information on the fast information channel (FIC) (step S40).

After the selection, the user control unit 204 retransmits the selected subchannel ID from the user control unit 204 to the channel decoder 203 to decode only the desired subchannel among the main service channels (step S50).

The channel decoder 203 receives the subchannel ID transmitted in step S50 and performs time deinterleaving only on the subchannel selected by the user among the main service channels (step S60).

The time deinterleaved sub-channel and the fast information channel (FIC) are muxed in the aggregator 404 in the channel decoder and transmitted to the convolutional decoder 405 and the energy descrambler 406 (step S70).

After the convolutional decoder 405 and the energy descrambler 406 are decoded by the fast information channel data decoder 117, the audio / data decoder 118, and the video decoder 119 according to each signal (step S80).

The respective decoded signals are finally displayed (step S90).

The decoded signal is decoded and displayed only in the sub-channel selected by the user for decoding among the main service channels received.

Through the above-described steps, only the channel selected and selected by the user is decoded and displayed.

The above-mentioned partial main service channel decoding is performed by each CIF unit constituting a transmission mode, and can be applied not only to the above-described transmission mode I but also to the remaining transmission modes II to IV.

In addition, the terminology used in the present invention is a general term that is currently widely used as possible, but in certain cases, the term is arbitrarily selected by the applicant, and in this case, since the meaning is described in detail in the corresponding part of the present invention, a simple term It is to be clear that the present invention is to be understood as a meaning of terms rather than names.

The present invention is not limited to the above-described embodiments, and as can be seen in the appended claims, modifications can be made by those skilled in the art to which the invention pertains, and such modifications are within the scope of the present invention.

The effects of the decoding method of the digital multimedia broadcasting receiver according to the present invention described above are as follows.

According to the present invention, it is possible to reduce power consumption and increase efficiency by decoding only the sub-channels that the user actually wants to view through the interface with the user, rather than decoding all the main service channels received.

Claims (6)

After demodulating the received signal, the demodulated signal is separated into a fast information channel (FIC) and a main service channel (MSC), and information about the quick information channel (FIC) is transmitted so that a user can decode the key service channel. Step S1 for selecting a desired subchannel; And step S2 of error correction, decoding, and displaying only sub-channels of the MSC selected by the user. According to claim 1, In the step S1, The selection means is a channel decoding method for receiving a digital multimedia broadcasting, characterized in that for receiving the ID of each sub-channel from the information on the fast information channel transmitted from among the sub-channel ID to be decoded. The method of claim 1, wherein the step S2, And time deinterleaving, convolutional decoding, energy descrambling, and RS decoding only the main service channel corresponding to the sub channel ID selected and transmitted by the user. Via an OFDM demodulator that demodulates the received signal, A channel decoder which transmits information on the quick information channel among the demodulated signals to a user control unit and decodes a subchannel selected and transmitted by a user; And a user controller which selects an ID of a subchannel desired to be decoded from the information on the quick information channel received from the channel decoder and transmits the ID to the channel decoder. The method of claim 4, wherein the channel decoder, A block aggregater for separating the demodulated signal transmitted in OFDM symbol units into a fast information channel and a primary service channel signal; A time inverse interleaver which receives a sub channel ID from the user controller and deinterleaves only a selected sub channel among the main service channels; An aggregater for muxing the fast information channel and the deinterleaved subchannel; A convolutional decoder that convolutionally decodes the coarse signal and performs error correction; And an energy inverse scrambler for decoding the error corrected signal into an original signal. The method of claim 4, wherein And the user controller serves as an interface with the channel decoder to decode only a subchannel desired by a user.

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