KR20060083618A - Data mode detector in digital multimedia broadcasting a receiving set - Google Patents

Abstract

The present invention relates to a data mode detector in a forward error correction encoding unit of a digital multimedia broadcasting receiver. The present invention relates to receiving a pilot channel for receiving a start position of each superframe from a frame and superframe extraction circuitry and detecting a desired data mode value. A CRC decoder for checking whether an error occurs or not and determining reliability; An automatic / manual selection unit for determining and determining whether a pilot channel transmitted after the determination is in an automatic mode or a manual mode; A pilot information decoder for decoding a pilot information according to the selected mode to obtain a data mode value; A reliability counter which counts the obtained data mode value, determines whether or not the reliability is determined, and transmits the result to a pilot information decoder; The present invention provides a digital multimedia broadcasting receiver including a data mode detector comprising an output signal generator for transmitting a data mode value and a flag transmitted from the pilot information decoder to a bit deinterleaver and a Viterbi decoder.

Therefore, according to the present invention, the pilot channel information is reliable, and there is an effect that it can cope with a data mode value changing in the process of being transmitted.

Data Mode Detectors, Reliability Counters, Pilot Channels

Description

Data Mode Detector in Digital Multimedia Broadcasting a receiving set

1 is a conceptual block diagram of a digital multimedia broadcasting receiver according to the present invention;

2 is a pilot channel super frame configuration diagram related to the present invention.

3 is a pilot channel frame configuration diagram related to the present invention.

4 is a block diagram illustrating a configuration of a data mode detector according to the present invention.

* Explanation of symbols for the main parts of the drawings

110: CRC decoder 120: automatic / manual selection unit

130: pilot information decoder 140: reliability counter

150: output signal generator

The present invention relates to a digital multimedia broadcasting receiver, and more particularly, to a data mode detector in a forward error correction encoder.

Digital multimedia broadcasting can be classified into terrestrial digital multimedia broadcasting and satellite digital multimedia broadcasting.

The terrestrial digital multimedia broadcasting provides audio and video services while moving based on Orthogonal Frequency Division Multiplexing (OFDM).

The satellite digital multimedia broadcasting is based on CDM (Code Division Multiplexing), using a gap filler on the ground which is a repeater used to solve the satellite and the shadow area that is not directly received by the satellite. It is possible to provide audio and video services on the go.

At present, the technology of satellite digital multimedia broadcasting basically adopts CDM transmission method, and is a new concept service of communication and broadcasting convergence, which broadcasts weather, traffic, video information using CD (Compact Disk) level sound quality and various channels.

The above-mentioned satellite digital multimedia broadcasting has an advantage of wide coverage as a national broadcasting, but the transmission channel is a wireless mobile reception channel, and the size of the received signal is not only time-varying, but also the Doppler of the received signal spectrum due to the influence of mobile reception. There is a problem that a shift occurs.

In consideration of the transmission and reception in such a channel environment, the satellite digital multimedia broadcasting transmission method adopts the CDM method, and interleaves the time domain signals to correct errors occurring in the transmission channel.

As described above, an object of the present invention is to propose a data mode detector in a forward error correction coding unit for error correction of a signal transmitted by interleaving or the like at a transmitter.

The present invention is directed to the above-described proposal, and an object of the present invention is to provide an efficient and reliable data mode detector suitable for data mode transmission of a pilot channel required by a digital multimedia broadcasting receiver currently under development.

In order to achieve the above object, the present invention determines the reliability of the received pilot channel by checking whether the received pilot channel error occurs in order to detect the desired data mode value by receiving the start position of each superframe from the frame and superframe extraction circuitry. A CRC decoder; An automatic / manual selection unit for determining and determining whether a pilot channel transmitted after the determination is in an automatic mode or a manual mode; A pilot information decoder for decoding a pilot information according to the selected mode to obtain a data mode value; A reliability counter which counts the obtained data mode value, determines whether or not the reliability is determined, and transmits the result to a pilot information decoder; The present invention provides a digital multimedia broadcasting receiver including a data mode detector comprising an output signal generator for transmitting a data mode value and a flag transmitted from the pilot information decoder to a bit deinterleaver and a Viterbi decoder.

When the automatic mode is selected in the automatic / manual selector, the data mode value is detected by decoding the pilot channel currently being input.

When the manual mode is selected, the data mode value preset in the receiving device is used as it is.

The pilot information decoder, when there is a change in the mode selected by the automatic / manual selection unit, transmits a flag indicating that the mode of the corresponding channel has changed together with the decoded value of the changed data mode value to the output signal generator.

The reliability counter uses a counter to count whether the same data mode value is continuously input in every super frame, and if the count value is equal to or higher than a predetermined level set in the receiver, a signal indicating that the decoded data mode value is reliable. Is transmitted to a pilot information decoder to output the decoded data mode value to an output signal generator.

In the output signal generator, the flag is transmitted when the bit deinterleaver and the Viterbi decoder are not always able to monitor when the decoded data mode value is to be transmitted.

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 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.

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

Looking at the receiving process of the receiving device, the received signal input to the antenna is converted from the tuner 10 to the baseband (Baseband), the converted signal is maintained in a constant size of the signal to the A / D (12) For this purpose, the A / D 12 is converted into a digital signal through an automatic gain control unit 11 that measures the power of the received signal and multiplies the calculated gain value.

In order to demodulate the signal in the CDM transmission scheme, the converted signal captures signal synchronization within -1/2 to +1/2 chip in the searcher 13, and tracks the signal captured by the searcher 13. The tracker 14 (1) to 14 (n) is used to finely track and synchronize the signal.

In the above description, the chip refers to a division unit of the pseudonoise sequence PN.

In this way, the signal that is captured, tracked and synchronized is despread by multiplying the pseudonoise sequence (PN) generated by the receiver, and multiplying by the WALSH code used to distinguish the CDM channels to extract the symbol of the desired CDM channel. (15 (1) to 15 (n)).

The above-described process is performed in all the multipaths found by the searcher 13, and each is called a finger.

Here, the frequency offset estimator 27 estimates the frequency offset for each finger, synthesizes it, and then feeds back the tuner 10 to correct the frequency offset.

The RAKE synthesizer 16 synthesizes the extracted symbols for all CDM channels for which demodulation is desired.

The timings of the frames and superframes of the symbols synthesized by the timing extraction circuit 17 of the frame and the superframe are extracted and transferred to the forward error correction encoder.

In this way, the signal sent from the rake synthesizer 16 is inputted to the forward error correction encoder, in which one pilot channel and four data channels correspond to the present invention, and are error corrected and displayed through the A / V data decoder 26. do.

There are two types of data mode values transmitted through pilot channels of the digital multimedia broadcasting system currently under development.

The first is an interleaving mode, and the second is a convolutional code rate.

The digital multimedia broadcasting system adopts a bit deinterleaver (19) in the forward error correction coding unit in order to correct the errors generated by distributing the collection errors occurring in the mobile reception environment.

This sets several modes to allow the interleaver's size to be adjusted according to the degree of fading, which is the interleaving mode.

In addition, since the convolutional encoder is used in the transmitter of the digital multimedia broadcasting system, the Viterbi decoder 21 must be used to decode the receiver.

At this time, by adjusting the code rate of the convolutional encoder of the transmitter, the ratio between the transmitted message bits and the parity bits can be adjusted, which is the convolutional code rate.

The data mode values described above are included in the pilot channel and transmitted. The data mode values are transmitted by being loaded in the structure shown in FIGS. 2 and 3.

The data mode value to be detected through the present invention, that is, the interleaving mode value and the convolutional coding rate, exist at a predetermined position of one superframe (or a frame constituting it).

2 is a diagram illustrating a pilot super frame structure of a digital multimedia broadcasting system according to the present invention. First, one super frame is composed of six frames (frame numbers 0 to 5), and each of the frames is a pilot signal and a data signal. It consists of.

The pilot signal is inserted for synchronization (position).

Each frame is composed of various pieces of information, which will be described in detail. FIG. 3 is a diagram showing the structure of a pilot frame of a digital multimedia broadcasting system according to the present invention.

Each frame includes pilot information (D3 to D22) and check bytes (D23 to D26) of an RS code, and the pilot information includes an identifier, payload data, and a cyclic redundancy check (CRC) for error detection. ').

The payload data includes CDM channel configuration information and receiver simultaneous additional information, and the CDM channel configuration information includes individual channel individual configuration information.

Each channel individual configuration information includes a data mode value (interleaving mode value and convolutional coding rate) to be obtained and remaining information.

Two data having the structure as shown in FIG. 3 are gathered to form one frame, and the formed frames are gathered to form one super frame.

Although the two data have the same structure, the contents may be different depending on the value sent from the transmitter.

Therefore, the start position of each super frame is received from the previous frame and super frame timing extraction circuit 17, and the relative position within the super frame and the frame is tracked to detect the data mode value.

In order to ensure the reliability of the pilot channel for detecting the data mode value, the data mode detector 24 counts whether a data mode value equal to or greater than a predetermined number of times set in the receiving apparatus comes in every super frame and is currently being input. The value is relied upon, and the decoded data mode value is transmitted to the actual bit deinterleaver 19 and the Viterbi decoder 21.

Referring to the configuration block of the data mode detector for the above operation, Figure 4 is a block diagram showing the configuration block of the data mode detector according to the present invention.

The data mode detector includes a CRC decoder 110, an automatic / manual selection unit 120, a pilot information decoder 130, a reliability counter 140, and an output signal generator 150.

The CRC decoder 110 checks whether an error occurs by using the output of the RS decoder 22 of the pilot channel as an input and determines whether to trust the output of the transmitted RS decoder.

The automatic / manual selection unit 120 may determine whether to select an automatic mode or a manual mode after determining the CRC decoder.

The manual mode refers to a data mode value which is mainly used in a digital multimedia broadcasting system currently being developed, which is set in advance to a receiving device, and the set data mode value is input. When the manual mode is selected, a preset data mode value is selected. Use them as they are.

The automatic mode refers to a case in which a data mode value different from the data mode value set in the manual mode is received. When the automatic mode is selected, a value that is set in advance in the receiving apparatus should not be used. The data mode value should be detected by decoding the channel directly.

Dynamic reconfiguration is not considered in the digital multimedia broadcasting receiver currently under development. That is, there is no mechanism for informing the pilot channel in advance that the data mode value of the pilot channel may change during transmission.

However, from the transmitter's point of view, the data mode values may be changed for securing broadcasting freedom or for other reasons.

Therefore, even in such a situation, the data mode detector 24 always monitors the pilot channel because it must detect the data mode value, but if the data mode value of the currently input pilot channel is different from the previously detected value, that is, the automatic If there is a change in the mode selected by the manual selection unit, the following pilot information decoder 130 may display a flag indicating that the mode of the corresponding pilot channel has changed, together with the changed data mode value, the bit deinterleaver 19 and the Viterbi decoder ( To 21).

The pilot information decoder 130 decodes the pilot information according to the mode selected by the automatic / manual selection unit 120. If the automatic mode is selected, the pilot information decoder 130 decodes the pilot channel currently being input to the data mode. Values are detected, and if the manual mode is selected, the data mode value preset in the receiving device is used as it is.

The confidence counter 140 counts using the counter whether the decoded pilot information is reliable and transmits a signal regarding the reliability to the pilot information decoder 130.

That is, the counting of the reliability is performed by checking whether the same data mode value comes in every superframe, and when the same data mode value is input for a predetermined level or more in the receiving apparatus, the data mode value that is currently input is relied on, and thus the actual first bit is counted. The inverse interleaver 19 and the Viterbi decoder 21 transmit a signal to the pilot information decoder so that the data mode value can be transmitted.

The output signal generator 150 transmits the transmitted data mode value to the bit deinterleaver 19 and the Viterbi decoder 21, and also the bit deinterleaver 19 and the Viterbi decoder 21. ) Is not always able to monitor whether the data mode value is coming, so it is characterized by sending a flag indicating that pilot information is transmitted.

As described above, the superframe and the frame extracting circuit 17 receive the values of the superframes and the start time of the frames of the pilot channels, decode the pilot channels, and detect the data mode values. Transmission to the Viterbi decoder 21 enables decoding on the desired data channel and allows the receiver to display the desired information.

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 effect of the data mode detector of the forward error correction coding unit according to the present invention is as follows.

First, when the pilot channel is decoded, a reliability counter is provided to transmit the decoded data mode value only when the same value is detected more than a predetermined number of times set in the receiving apparatus, thereby making it possible to reliably transmit the information of the transmitted pilot channel.

Secondly, when the data mode value changes, the side receiving the information has an effect that can correspond to this by transmitting a flag.

Claims (6)

In order to detect the desired data mode value by receiving the start position of each superframe from the frame and superframe extraction circuit, A CRC decoder for checking reliability of the received pilot channel and determining reliability; An automatic / manual selection unit for determining and determining whether a pilot channel transmitted after the determination is in an automatic mode or a manual mode; A pilot information decoder for decoding a pilot information according to the selected mode to obtain a data mode value; A reliability counter which counts the obtained data mode value, determines whether or not the reliability is determined, and transmits the result to a pilot information decoder; And an output signal generator for transmitting a data mode value and a flag transmitted from the pilot information decoder to a bit deinterleaver and a Viterbi decoder. The method of claim 1, wherein in the automatic / manual selection unit, And a data mode detector for detecting a data mode value by decoding a pilot channel currently being input when the automatic mode is selected. The method of claim 2, When the manual mode is selected, the digital multimedia broadcasting receiver including a data mode detector, using the data mode value preset in the receiver as it is. The method of claim 1, wherein the pilot information decoder, And a flag indicating that the mode of the corresponding channel has changed when the mode selected by the automatic / manual selection unit changes, and transmitting the flag along with the decoded value of the changed data mode value to the output signal generator. Multimedia broadcasting receiver. The method of claim 1, wherein the reliability counter, A pilot information decoder is used to count whether the same data mode value is continuously input every superframe using a counter, and if the count value is greater than or equal to a predetermined level set in the receiver, a signal indicating that the decoded data mode value is reliable. And a data mode detector for outputting the decoded data mode value to an output signal generator. The method of claim 1, wherein in the output signal generator, And the flag is transmitted to indicate when the bit deinterleaver and the Viterbi decoder are not always able to monitor when a decoded data mode value is to be transmitted.

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