JPH09130772A - Terminal equipment for digital television broadcast - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a receiver side to apply discrimination processing to a function that avoids charge imposition in the case of disable viewing of a pay broadcast due to deterioration in the C/N in a terminal equipment processing a signal in compliance with the digital television broadcast system using a broadcast communication satellite. SOLUTION: A signal received by an antenna 101 is frequency-converted by a tuner 102, a demodulation decoding processing section 103 decodes a video image and an audio signal from the signal and provides an output of them to a monitor/speaker 105. When the received signal is scrambled in the case of the demodufation decoding processing, key data used for descrambling are received from an IC card 108 and a descramble processing section 104 makes descramble processing. A C/N detection section 106 detects a C/N of the received signal in the case of demodulation decoding processing, a charging discrimination processing section 107 discriminates whether or not viewing is made based on a detection level and when the viewing is made, the charging information is written on the IC card 108.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital television broadcasting terminal device conforming to a digital television broadcasting system using a communication satellite (CS).

[0002]

[Background Art] DirectTv Inc. of the United States started digital satellite broadcasting in 1994, followed by CanalPlus of France and BskyB of the United Kingdom.
, Hong Kong Star TV will also start broadcasting. Japan also,
In July 1995, the Telecommunications Technology Council submitted a report on the standard method of digital broadcasting, and in the spring of 1996 broadcasting using Japan Satellite Systems' (JSAT) No. 3 satellite (JCSAT-3) will begin.

According to this standard system, MPEG2 (Motion Picture Exper) is an international standard for compressing video data and audio data.
It is compressed in ts Group Phase 2) and multiplexed with service data (program guide data) etc. into packet format. The packet at this time is a transport packet (Tra
nsport Packet), and the packet length is a fixed length of 188 bytes.

Of the 11 specifications of MPEG2, MP @ ML (Main Profile at Main Level) is expected to be used for the time being, but in the future, HDTV (High Definition T
(elevision) It is not specified in the standard system so that it can also be used for broadcasting. The coding speed is also left unspecified at the discretion of the broadcaster. The packetized data is then encrypted and then scrambled. This is to prevent the energy of the satellite wave from deviating due to continuous specific bit patterns. Next, an error correction code is added to each packet. Then, interleaving and convolutional coding are performed. The Viterbi algorithm is used for this decoding. The reason for interleaving is to cope with burst errors. Convolutional coding can be selected from 5 types of 1/2, 2/3, 3/4, 5/6, 7/8. Finally, QPSK (Quadrature Phase Shift
Keying) Modulate and transmit.

A transponder (repeater) 1 using QPSK
42.192 Mbit / sec data is transmitted with a frequency bandwidth of 27 MHz per book. Excluding the error correction code, the rate is 31.644 Mbit / sec. A combination of QPSK modulation and MPEG2 can be used to broadcast about 50 channels using eight transponders.

To receive this digital broadcast, an IC card to be inserted into the receiver is required in addition to the antenna and the receiver. The receiver includes a tuner circuit, a QPSK demodulation circuit, a decryption circuit, and an MPEG2 decoding circuit.

Of these, individual numbers are registered in the IC card and distributed to viewers. When a pay-broadcast program is received, whether or not to watch is determined from the registration number of the IC card.
When viewing is possible, the key data for descrambling is transferred from this IC card to the receiver.

[0008]

In the conventional pay satellite broadcasting, the viewing fee is on a channel-by-channel basis, but in the digital television broadcasting, the pay-per-view (Pay Per View) is used.
It is structured such that it is charged for each program called View).

Since the transmission power of communication satellites in satellite broadcasting is very weak, the attenuation of radio waves (decrease in C / N) due to rainfall and obstacles is large (for example, Journal of Television Engineers Vol.48, No1,
pp57-64).

Therefore, the viewing fee is charged even if the pay broadcast is received but cannot be received at all, or even if the viewer can only partially or partially view the broadcast.

The present invention has been made in order to solve such a problem, and if the data such as the video signal and the audio signal is not demodulated due to the C / N attenuation, the billing process is performed. It is an object of the present invention to provide a digital television broadcasting terminal device having a function not to be performed.

[0012]

In order to achieve the above object, the terminal device for digital television broadcasting of the present invention has an antenna section for receiving a digital broadcasting signal sent from a satellite and a signal received by the antenna at 480 MHz. Or 70MH
Tuner that converts to low frequency band up to z, QPSK demodulation processing of frequency converted signal, error correction processing, deinterleave processing, data such as video, audio data and service data compressed from transport packet by MPEG2 method Separated transport processing, demodulation and decoding processing unit that performs decoding processing that expands compressed video and audio data, monitor that displays and outputs decoded video and audio data, speaker unit, and scramble processing is performed. Descramble processing unit for recovering transport packet data, data error rate detection unit for detecting data error rate when demodulating and decoding transmitted data, billing processing is performed based on the detected data error rate A billing determination processing unit that determines whether or not there is a charge, when the billing is determined to be performed, the billing information is written and a fee is charged. And an IC card unit for passing the key data for performing the descramble processing only to the person who has selected the program.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION With the above configuration, the terminal device for digital television broadcasting of the present invention does not write charging information to the IC card when a pay broadcast program cannot be viewed due to C / N attenuation. The function can be realized.

An embodiment of the present invention in a digital television broadcasting terminal device will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of the arrangement of a digital television broadcasting terminal device according to the first embodiment of the present invention. The output of the antenna 101 is connected to the input of the tuner 102. The output of the tuner 102 is connected to the first input of the demodulation / decoding processing unit 103. The first output of the demodulation / decoding processing unit 103 is the descramble processing unit 10
4 is connected to the first input. Demodulation / decoding processing unit 103
The second output of is connected to the monitor / speaker 105. Further, the third output of the demodulation / decoding processing unit 103 is connected to the input of the data error rate detection unit 106. The output of the data error rate detection unit 106 is connected to the input of the billing determination processing unit 107. The output of the billing determination processing unit 107 is IC
It is connected to the input of the card 108. The output of the IC card 108 is connected to the second input of the descramble processing unit 104.

Next, the operation of the digital television broadcasting terminal device of the present embodiment having the above-mentioned configuration will be described. In FIG. 1, a digital television signal is input from the antenna 101 and input to the tuner 102. The tuner 102 frequency-converts the input signal to a low frequency of 480 MHz or 70 MHz. The demodulation and decoding processing unit 103 performs QP on the signal output from the tuner 102.
Performs SK demodulation, error correction, and deinterleave. Also,
When the demodulated signal is scrambled and the viewer requests to view a pay broadcast program, the IC
Key data for performing the descramble processing is output from the card 108, and the signal scrambled by the descramble processing unit 104 is descrambled and restored by the key data. Then, the descrambled signal is separated into other data such as a compressed video signal, audio signal and service data. Further, a decoding process for expanding the separated video data and audio data is performed and output to the monitor / speaker 105. The C / N detection unit 106 performs C / N detection processing on the signal output from the demodulation / decoding processing unit 103. When C / N is low, the signal cannot be correctly demodulated by QPSK demodulation. With a low C / N, even if error correction processing is performed, it cannot be corrected. In that case, it is possible that the data is incorrect, not locally. Therefore, since the transport packets cannot be synchronized, the video and audio data cannot be correctly decoded, and the viewer cannot watch the program.

Therefore, the viewer pays a program depending on the information indicating that the C / N value output from the C / N detector 106 is low and the time during which the demodulation cannot be performed occupies the entire program broadcasting time. Is determined by the billing determination processing unit 107 as to whether or not it has been viewed sufficiently, and if it can be viewed, then the IC
The charging information is written in the card 108, and when it is determined that the viewing is not possible, the processing of not writing the charging information in the IC card 108 is performed.

As described above, according to this embodiment, it is possible to control the writing of the charging information by judging whether the viewer can watch the program or not by the C / N level of the received signal, and the viewer can be controlled. It is possible to realize a function of not charging when the pay program cannot be viewed.

FIG. 2 is a block diagram showing a configuration example of a digital television broadcasting terminal device according to the second embodiment of the present invention.

The output of the antenna 201 is the tuner 202.
Connected to the input of The output of the tuner 202 is connected to the first input of the demodulation / decoding processing unit 203. The first output of the demodulation / decoding processing unit 203 is connected to the first input of the descramble processing unit 204. Demodulation / decoding processing unit 2
The second output of 03 is connected to the monitor / speaker 205. The third output of the demodulation / decoding processing unit 203 is
It is connected to the input of the error packet rate detection unit 206. The output of the error packet rate detection unit 206 is connected to the input of the billing determination processing unit 207. The output of the billing determination processing unit 207 is connected to the input of the IC card 208. The output of the IC card 208 is the second of the descramble processing unit 204.
Connected to the input of

The operation of this embodiment will be described below. In the present embodiment, the demodulation / decoding processing unit 20 determines whether the viewer in the first embodiment can or cannot watch the pay program.
The determination is made by detecting the presence or absence of error bits in the output transport packet of No. 3. As shown in FIG. 3, the transport packet has 1 byte of synchronization byte in the transport header of 4 bytes in 188 bytes of 1 packet. Since the pattern of the synchronization byte is fixed, if synchronization is lost, it is considered that a bit error due to noise has occurred in the synchronization pattern. If the transport packets cannot be synchronized, the video signal and audio signal cannot be decoded. Then, the viewer cannot watch the program. Therefore, whether or not to write the billing information in the IC card is determined according to the ratio of the number of transport packets that cannot be synchronized during the pay broadcast program to the total number of transport packets.

As described above, according to the present embodiment, it is possible to judge whether or not the viewer has been able to watch the program by the packet synchronization processing in the transport processing, and the viewer cannot watch the pay program. In this case, the function of not charging can be realized.

FIG. 4 is a block diagram showing an example of the arrangement of a digital television broadcasting terminal device according to the third embodiment of the present invention.

The output of the antenna 401 is the tuner 402.
Connected to the input of The output of the tuner 402 is connected to the first input of the demodulation / decoding processing unit 403. The first output of the demodulation / decoding processing unit 403 is connected to the first input of the descramble processing unit 404. Demodulation / decoding processing unit 4
The second output of 03 is connected to the monitor / speaker 405. Further, the third output of the demodulation / decoding processing unit 403 is
It is connected to the input of the error packet rate detection unit 406. The output of the error packet rate detection unit 406 is connected to the input of the billing determination processing unit 407. The output of the billing determination processing unit 407 is connected to the input of the IC card 408. The output of the IC card 408 is the second output of the descramble processing unit 404.
Connected to the input of

In this embodiment, the presence or absence of error bits in the transport packet in the second embodiment is realized by looking at the error indicator in the transport header.

The 1-bit error indicator in the transport header of FIG. 3 is a flag indicating that there is at least one bit error in the packet. Therefore, if there are many error indicators, video data,
If the important data is an error when decoding the audio data, the video and audio signals cannot be correctly decoded. Therefore, whether or not to write the billing information in the IC card is determined by the ratio of the transport packets having error bits in the pay broadcast program to all the transport packets.

As described above, according to this embodiment, it is possible to judge whether or not the viewer can watch the program by detecting the error indicator in the transport header, and the viewer watches the pay program. If it is not possible, the function of not charging can be realized.

In this embodiment, the presence or absence of the error bit in the third embodiment is determined by using the data used in the MPEG2 video decoding process. The compressed video data includes data that defines the format of the video to be decoded. It contains data specific to the digital television standard system such as the horizontal size, vertical size of the screen, and transmission system. Therefore, a local bit error can be detected by detecting the unique data and comparing it with a correct value. If the frequency of occurrence of bit errors is high due to the ratio of the number of bits compared to the number of detected bit errors, it is determined that the video data and audio data could not be correctly decoded.

As described above, according to this embodiment, it is possible to judge whether or not the viewer can watch the program by detecting the unique data such as the image format information in the compressed video data. It is possible to realize a function of not charging if the viewer cannot watch the pay program.

FIG. 5 is a block diagram showing a configuration example of a digital television broadcasting terminal device according to the fifth embodiment of the present invention.

The output of the antenna 501 is the tuner 502.
Connected to the input of The output of the tuner 502 is connected to the first input of the demodulation / decoding processing unit 503. The first output of the demodulation / decoding processing unit 503 is connected to the first input of the descramble processing unit 504. Demodulation / decoding processing unit 5
The second output of 03 is connected to the input of monitor / speaker 505. Further, the third output of the demodulation / decoding processing unit 503 is connected to the input of the C / N detection unit 506. The fourth output of the demodulation / decoding processing unit 503 is connected to the input of the error packet rate detection unit 507. Demodulation / decoding processing unit 50
The fifth output of 3 is the video data error rate detection unit 508.
Connected to the input of The output of the C / N detection unit 506 is connected to the first input of the billing determination processing unit 509. The output of the error packet rate detection unit 507 is output by the billing determination processing unit 509.
Is connected to the second input of. The output of the video data error rate detection unit 508 is connected to the third input of the billing determination processing unit 509. The output of the billing determination processing unit 509 is connected to the input of the IC card 510. The output of the IC card 510 is connected to the second input of the descramble processing unit 504.

This embodiment includes all of the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment, and the output of the C / N detection unit 506 and the error packet rate detection unit 507. Based on the output and the output information of the video data error rate detection unit 508, the charge determination processing unit 509 determines whether or not the pay broadcast can be viewed.

[0033]

As described above, the present invention determines whether or not a viewer can watch a pay broadcast program when receiving a digital television signal with a low C / N, the C / N level, the error packet rate, By judging based on the video data error rate, it is possible to realize the function of stopping the writing of the billing information when the viewing is impossible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of second and third embodiments of the present invention.

FIG. 3 is a diagram showing a data structure of a transport packet.

FIG. 4 is a block diagram showing a configuration of a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a fifth embodiment of the present invention.

[Explanation of symbols]

 101 antenna 102 tuner 103 demodulation / decoding processing unit 104 descrambling processing unit 105 monitor / speaker 106 C / N detection unit 107 billing determination processing unit 108 IC card 201 antenna 202 tuner 203 demodulation / decoding processing unit 204 descramble processing unit 205 monitor / Speaker 206 Error packet rate detection unit 207 Charge determination processing unit 208 IC card 401 Antenna 402 Tuner 403 Demodulation / decoding processing unit 404 Descramble processing unit 405 Monitor / speaker 406 Video data error rate detection unit 407 Charge determination processing unit 408 IC card 501 antenna 502 tuner 503 demodulation / decoding processing unit 504 descrambling processing unit 505 monitor / speaker 506 C / N detection unit 507 error packet rate detection unit 08 video data error rate detecting unit 509 charging determination processing unit 510 IC card

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Kubota 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] An antenna for receiving a digital television signal, a tuner for converting a signal output by the antenna to a low frequency, a demodulation decoding processing unit for demodulating and decoding a signal output by the tuner, and the demodulation decoding processing unit. Descramble processing of the scrambled signal output by and output to the demodulation decoding processing section and a monitor for displaying and outputting the video signal and audio signal decoded and output by the demodulation decoding processing section, C / of the received signal from the signal output from the speaker unit and the demodulation / decoding processing unit
The C / N detecting section for detecting the N level, and the billing discriminating processing section for discriminating whether or not the pay program can be viewed from the C / N signal outputted by the C / N detecting section and for deciding whether to charge or not. Writing the billing information output by the billing determination processing unit to the IC card If the IC card unit and the program are scrambled, and if the viewer can watch, the key data for descrambling is output to the descrambling unit. It is characterized by having an IC card section. Terminal equipment for digital television broadcasting. 2. The terminal device for digital television broadcasting according to claim 1, wherein whether or not the viewer has been able to watch the pay broadcast is determined by an error packet rate by detecting a synchronization byte of a transport packet. 3. The terminal device for digital television broadcasting according to claim 1, wherein whether or not the viewer is able to watch the pay broadcast is detected and determined by detecting an error indicator of the transport packet. 4. A method for determining whether or not a viewer has been able to watch a pay broadcast by detecting a value specific to compressed video data. An error packet rate is detected and determined by detecting an indicator. The terminal device for digital television broadcasting according to claim 1. [Claim 5] Whether or not the viewer was able to watch the pay broadcast C
2. The determination is made by detecting / N, detecting an error packet rate, and detecting a video data error rate.
Digital television broadcasting terminal device.