JP3717422B2 - Digital broadcast receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for reducing the power consumption of a digital broadcast receiving device when the digital broadcast receiving device has a function other than the function of receiving a broadcast wave, for example, when a transmitting unit of a mobile terminal unit is operating.
[0002]
[Prior art]
In terrestrial broadcasting, digitization is performed to improve services by digitalization and to realize effective use of bandwidth by SFN (Singe 1 Frequent Cy Network) and MFN (Multi Frequency Network). According to this, it is possible to broadcast one program for HDTV and three programs for SDTV using a 6 MHz region. At the same time, high-quality broadcasting services and data broadcasting services will be realized.
[0003]
In general, video / audio information, which is content information in digital broadcasting, is compressed by the MPEG2 system, and data broadcasting is generated by a recarous cell transmission system using the BML language. The compressed video, audio information, and data broadcast are multiplexed to generate a transport stream (TS). The generated TS signal is efficiently modulated and transmitted by a digital modulation method.
[0004]
In the case of digital terrestrial broadcasting, the BST-OFDM (Band Segmented Transmission-Orthogonal Frequency Division MuI multiplexing) method is adopted in Japan, and this method is a multi-carrier transmission method using a plurality of carriers at the same time. They are orthogonal and modulated with DQPSK, QPSK, 16QAM, 64QAM. The number of carriers used is about 1400 to 5600 in domestic terrestrial digital broadcasting, and OFDM modulation and OFDM demodulation are performed by inverse Fourier transform and Fourier transform, respectively.
[0005]
In actual transmitters and receivers, 2K points to 8K points of I-DFT (Inverse-Discrete Fourier Transform) processing and DFT (Discrete Fourier Transform) processing are used.
[0006]
Unlike satellite broadcasting, terrestrial digital broadcasting generates reflected waves due to obstacles such as buildings and mountains, which become ghosts and cause errors in the redigital modulation signal. For this reason, in the receiver, video and audio signals are broken, and reception quality is significantly deteriorated. In general, signal degradation due to noise can be corrected by error correction if the received signal satisfies the required C / N, and video / audio can be reproduced without error in the receiver.
[0007]
As described above, in order to absorb the influence of interference due to ghosts and multipaths, the OFDM system is devised so as not to cause information corruption even if a delay wave exists by providing a buffer region. This buffer area is called a guard interval (GI). Since the code interference does not occur unless the delay time of the delay wave of the received signal exceeds the guard interval time, the error correction circuit can correct it. If the guard interval is exceeded, intersymbol interference occurs and causes an error. The guard interval length is set to 1/4, 1/8, 1/16, 1/32 of the total transmission signal length, which corresponds to about 8 to 250 microseconds.
[0008]
In general, in mobile reception and mobile reception in terrestrial broadcasting, a signal digitally modulated by multipath fading or the like deteriorates and an error occurs. The OFDM system adopted for digital broadcasting uses a concatenated code together and incorporates time interleaving to make it a system that is strong against mobile reception and mobile reception.
[0009]
The configuration of a conventional receiver is shown in FIG. A desired channel is selected by a tuner 12 which is a channel selection unit and output from a signal from an antenna 11 that receives a broadcast wave. The selected IF signal is converted into a re-digital signal by the ADC 13 that performs analog-digital conversion. The IF signal converted into the digital signal is OFDM demodulated by the OFDM demodulator 14 and decoded by the decoder 15 to output a TS signal.
[0010]
The output TS signal is demultiplexed by the demax decoder 14, and each video / audio / data broadcast stream is output. Each of the separated signals is subjected to information decoding processing and converted into viewable information. Video is subjected to MPEG2 decoding and the like, and audio is mainly subjected to AAC decoding. Data broadcasting performs carousel processing, processes information embedded with MPEG4 and the like, and enables viewing of still images, simple moving images, and the like.
[0011]
In digital terrestrial broadcasting, this mobile OFDM-resistant system enables high-quality mobile reception and mobile reception services, and a new system can be constructed using a digital broadcast receiver (composite terminal) or the like in which a broadcast receiver is combined with communication means. .
[0012]
[Problems to be solved by the invention]
As described above, when services for mobile reception and mobile reception are performed in terrestrial digital broadcasting, the digital broadcast receiving device can view content such as normal video, audio, and data broadcasting, and communication means. New viewing modes and devices, such as interactive services, can be realized by interlocking with each other. Such a digital broadcast receiving apparatus (receiving terminal) is often operated with a battery, and it is desired to reduce its power consumption. For example, the power consumption during roaming of the transmitter of the communication means overlaps with the continuous operation of the broadcast wave receiver, resulting in an instantaneous increase in power consumption and an increase in the burden on the battery.
[0013]
In addition, when the digital broadcast receiving apparatus is viewing content, in the case of data broadcasting, etc., when information is repeatedly transmitted in the carousel, the received content information can be viewed by performing decoder processing in that cycle. Is possible. For example, if the carousel has a period of 15 seconds and is updated after 3 minutes, it will be repeatedly transmitted 12 times. If one period of information can be completely acquired at this time, the processing of the broadcast wave receiving unit will continue to receive the same information. As a result, redundant operations are performed.
[0014]
For this reason, when content information is repeatedly transmitted in the digital broadcast receiving apparatus, it is not necessary to set the reception operation to a normal reception operation, and the operation can be completely or partially stopped. .
[0015]
In this way, even when there is a limit to battery or power, such as a small digital broadcast receiver, etc., power can be used efficiently and power consumption can be kept low, and the operation of the digital broadcast receiver can be reduced. The operating time can be extended stably.
[0016]
In a digital broadcast receiver combined with a communication means such as a mobile phone, power is consumed due to the transmission state such as roaming processing of the communication means, and if the operation with the broadcast wave receiver occurs simultaneously, the load on the battery is large. Power consumption becomes significant.
[0017]
In order to solve such problems, an object of the present invention is to provide a digital broadcast receiving apparatus that efficiently reduces power consumption by stopping the operation of the broadcast wave receiving unit by the transmission operation of the communication means including the portable terminal unit. Is to provide. Another object of the present invention is to control the operation of the digital broadcast receiving apparatus in accordance with the type of content information including data broadcast so as to suppress power consumption.
[0018]
[Means for Solving the Problems]
In order to solve the above problems, the present invention mainly adopts the following configuration. In a digital broadcast receiving apparatus having an antenna for receiving a broadcast wave by orthogonal frequency division multiplexing (OFDM),
Channel selection means for selecting a desired frequency band from a signal received by the antenna;
An analog-digital conversion circuit that converts the signal selected by the channel selection means into a digital signal;
An OFDM demodulator that digitally demodulates the signal digitally converted by the analog-to-digital converter;
A decoding unit for decoding from the demodulated signal demodulated by the OFDM demodulation unit;
A demultiplexing unit that performs demultiplexing from the transport stream signal decoded by the decoding unit;
A decoder unit for decoding information from the signal demultiplexed by the demax unit;
A communication means that enables mobile transmission / reception or portable transmission / reception services;
Digital broadcasting that temporarily stops the operation of all or a part of the channel selection unit, the analog-digital conversion circuit, the OFDM demodulation unit, and the decoding unit when a control signal from the communication unit operates. Receiver device.
[0019]
Also, in the digital broadcast receiving apparatus, the control signal is a signal that is a signal that detects a state in which a transmission function of the communication means shifts to an operating state.
[0020]
In addition, in a digital broadcast receiver equipped with an antenna for receiving broadcast waves by orthogonal frequency division multiplexing (OFDM),
Channel selection means for selecting a desired frequency band from a signal received by the antenna;
An analog-digital conversion circuit that converts the signal selected by the channel selection means into a digital signal;
An OFDM demodulator that digitally demodulates the signal digitally converted by the analog-to-digital converter;
A decoding unit for decoding from the demodulated signal demodulated by the OFDM demodulation unit;
A demax decoder unit that decodes information by demultiplexing from the transport stream signal decoded by the decoding unit,
The demux decoder unit detects a carousel acquisition state of data broadcasting, and temporarily or temporarily operates the channel selection unit, the analog-digital conversion circuit, the OFDM demodulation unit, and the decoding unit based on the detection signal. Digital broadcast receiving device to be stopped.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
A digital broadcast receiver according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram illustrating an overall configuration of a digital broadcast receiving apparatus including a mobile terminal unit in addition to a broadcast wave receiving unit according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a power control configuration of a digital broadcast receiving apparatus including a broadcast wave receiving unit according to another embodiment of the present invention. FIG. 3 is a diagram illustrating operation timing between the transmission unit and the broadcast wave reception unit of the mobile terminal unit. FIG. 4 is a diagram showing the operation timing of the broadcast wave receiving unit.
[0022]
In FIG. 1, first, the digital broadcast receiver 19 is mainly composed of a broadcast wave receiver 18 that receives broadcast waves, a portable terminal 32 (an example of communication means), and a controller 21 that controls the operation of both. Yes. Then, in the broadcast wave receiving unit 18 of the digital broadcast receiving apparatus 19 that receives the broadcast wave transmitted from the broadcast station by the receiving antenna 11, the signal received by the antenna 11 is sent to the tuner 12 that is a channel selecting unit for channel selection. Select the frequency you want to receive. The selected signal is converted into a redigital signal by an analog-to-digital converter (ADC) 13 and demodulated by an OFDM demodulator 14 that digitally demodulates an orthogonal frequency division multiplex (OFDM) signal. The demodulated signal is decoded by the decoding unit 15 and output as a transport stream signal (TS signal).
[0023]
The transport signal is defined by the MPEG2-systems standard, and video / audio / data broadcasting and SI / PSI signals are multiplexed. The transport signal output from the decoding unit 15 is subjected to demultiplexing processing by the demax / decoder unit 16 and separated into content information such as video / audio / data broadcasting and control signals (SI / PSI signals) (filtering processing). ).
[0024]
The separated signals are subjected to decryption processing of each content, and processed into information that can be viewed. The video signal is subjected to MPEG2 decoding, and the audio signal is mainly subjected to AAC decoding. Data broadcasting performs carousel processing and displays information using a BML browser. In addition, information embedded with MPEG4 or the like is processed to allow viewing of still images and simple moving images.
[0025]
Then, voice and information are transmitted and received by the portable terminal unit 32 which is an example of a communication means. Information from the microphone 28 is amplified by the amplifier 27, subjected to modulation multiplexing processing by the modulation unit 26 and the time division multiplexing unit 25, amplified by the high frequency amplifier 24, and output from the antenna 23 (transmission of the portable terminal unit 32). Operation in the department). On the other hand, the signal received by the antenna 23 is amplified by the high-frequency amplifier 24, demodulated by the time division multiplexing 25 and the demodulator 29, amplified by the amplifier 30, and the sound is output by the speaker 31 (mobile phone). Operation in the receiving unit of the terminal unit 32).
[0026]
The mobile terminal unit shown here shows a typical structure of a current mobile phone. However, the mobile terminal unit is not limited to this, and may be a next-generation mobile phone (IMT200) or the like that will appear in the future. . A similar effect can be expected with a PDA having a transmission function.
[0027]
The mobile terminal unit 32 performs roaming at intervals of several hundred ms (see FIG. 3), and power for this transmission is consumed. In the present invention, this roaming state is detected, and the operations of the tuner unit 12, the ADC 13, the OFDM demodulator unit 14, and the decoding unit 15 in the broadcast wave receiving unit 18 are temporarily stopped to reduce power consumption. For example, the tuner 12, the ADC 13, the OFDM demodulator 14, and the decoder 15 are controlled by the power controller 20 of the broadcast wave receiver 18 through the controller 21 depending on the transmission state of the transmission controller 22 in the mobile terminal unit 32. The operation is temporarily stopped to reduce power consumption.
[0028]
Further, only the ADC 13, the OFDM demodulator 14, and the decoder 15 may stop the operation. Further, only the operation of the OFDM demodulator 14 and the decoder 15 may be stopped. Further, the operation of only the decoding unit 15 may be stopped. When the broadcast wave receiving unit 18 is stopped, the operation of the decoder unit after the broadcast wave receiving unit may also be stopped.
[0029]
When the operations of the OFDM demodulator 14 and the decoder 15 are stopped, the synchronization operation of the broadcast wave receiver 18 can be made continuous so that the operation can be quickly recovered when the reception operation is recovered.
[0030]
FIG. 3 is a timing chart showing typical operations in the broadcast wave receiving unit 18. Here, if the mobile terminal unit 32 performs transmission at intervals of about 640 ms for roaming or the like, the state is sent from the transmission control unit 22 to the power control unit 20 via the control unit 21, and the mobile terminal unit 32 is transmitted. Is in a transmitting state, the reception operation of the broadcast wave receiving unit 18 is intermittently stopped. Based on the control signal of the power control unit 20, the operations of the tuner unit 12, ADC 13, OFDM demodulation unit 14, and decoding unit 15 are temporarily or partially stopped to suppress power consumption.
[0031]
The roaming timing of the portable terminal unit 32 is sent to the control unit 21 based on the information from the transmission control unit 22, and is synchronized with the power control unit 20 to control the transmission timing for roaming. Wave receiver operation is performed exclusively, and power consumption can be suppressed. Also, at the time of transmission for reply to the communication carrier, the operation of the broadcast wave receiving unit may be temporarily or partially stopped in the same manner as described above.
[0032]
Next, FIG. 2 shows a representative block diagram of another embodiment of the present invention. As for the signal from the antenna 11 that receives the broadcast wave, the tuner 2 for channel selection extracts one desired frequency and outputs an IF signal. The output IF signal is converted into a re-digital signal by an analog-digital converter (ADC) 13 and demodulated by an OFDM demodulator 14 that digitally demodulates an orthogonal frequency division multiplexing (OFDM) signal. The demodulated signal is decoded by the decoding unit 15 and output as a transport stream signal (TS signal). The transport signal is defined by the MPEG2-systems standard, and video / audio / data broadcasting and SI / PSI signals are multiplexed.
[0033]
The transport signal decoded by the decoding unit 15 is subjected to demultiplexing processing by the demax / decoder unit 16 and is divided into the content information (video / audio / data broadcast) and the control signal (SI / PSI signal) (filtering processing). ). The demultiplexed signal is decoded by the decoder 16 to re-content information, and a video signal, an audio signal, and a data broadcast are output.
[0034]
Among digital broadcasting, data broadcasting uses a carousel data transmission system, and the same information is sent periodically. In the digital broadcast receiving apparatus of the present invention, once the data broadcast information is acquired, it is not necessary to receive the data until the information is updated, so the reception operation is temporarily stopped. The broadcast control unit 35 detects the carousel acquisition state of the demax decoder unit 16 and sends a control signal to the power control unit 20. The power control unit 20 operates the tuner 12, ADC 13, OFDM demodulation unit 14, and decoding unit 15. Is temporarily or partially stopped to reduce power consumption.
[0035]
FIG. 4 is a timing chart showing the power control operation in data broadcasting. In the present invention, the digital broadcast receiving operation is stopped for a predetermined period (interval) to suppress the power consumption accompanying the reception of the broadcast wave. At this time, the interval is variable, and when the acquisition of the carousel data of the data broadcast in the broadcast wave is completed, further power saving can be achieved by stopping the receiver operation.
[0036]
As described above, the operation description of the embodiment of the present invention is outlined. When the mobile terminal unit roams, the operation of the broadcast wave receiving unit is stopped in synchronization with the transmission unit of the mobile terminal unit, and the communication carrier The operation of the broadcast wave receiving unit is stopped at the time of transmission for replying to the above, and the operation of the broadcast wave receiving unit is stopped and the operation is started after an interval after acquiring the carousel at the time of data broadcast reception.
[0037]
【The invention's effect】
According to the present invention, in a receiving device equipped with a broadcast wave receiving unit and a portable terminal unit having a transmitting unit, the transmission state of the transmitting unit is detected and the reception operation of the broadcast wave receiving unit is stopped. Electric power can be reduced.
[0038]
In addition, it is possible to reduce power consumption by detecting the reception status of data broadcasting, etc., stopping all or part of the operation of the broadcast wave receiver after the carousel acquisition, and operating again at intervals. It is.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of a digital broadcast receiving apparatus including a mobile terminal unit in addition to a broadcast wave receiving unit according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a power control configuration of a digital broadcast receiving apparatus including a broadcast wave receiving unit according to another embodiment of the present invention.
FIG. 3 is a diagram illustrating operation timing between a transmission unit and a broadcast wave reception unit of a mobile terminal unit.
FIG. 4 is a diagram illustrating an operation timing of a broadcast wave receiving unit.
FIG. 5 is a diagram illustrating an overall configuration of a digital broadcast receiving apparatus according to a conventional technique.
[Explanation of symbols]
11 Broadcast wave receiving antenna 12 Tuner 13 ADC
14 OFDM demodulator 15 Decoder 16 Demax decoder 17 Output terminal 18 Broadcast wave receiver 19 Digital broadcast receiver 20 Power controller 21 Controller 22 Transmit controller 23 Transmit / receive antenna 24 High frequency amplifier 25 Time division multiplexing 26 Modulator 27 Amplifier 28 Microphone 29 Demodulator 30 Amplifier 31 Speaker 32 Mobile Terminal 40 Controller

Claims (4)

In a digital broadcast receiving apparatus having an antenna for receiving a broadcast wave by orthogonal frequency division multiplexing (OFDM),
Channel selection means for selecting a desired frequency band from a signal received by the antenna;
An analog-digital conversion circuit that converts the signal selected by the channel selection means into a digital signal;
An OFDM demodulator that digitally demodulates the signal digitally converted by the analog-to-digital converter;
A decoding unit for decoding from the demodulated signal demodulated by the OFDM demodulation unit;
A demultiplexing unit that performs demultiplexing from the transport stream signal decoded by the decoding unit;
A decoder unit for decoding information from the signal demultiplexed by the demax unit;
A communication means that enables mobile transmission / reception or portable transmission / reception services;
When the communication means operates, the operation of all or part of the channel selection unit, the analog-digital conversion circuit, the OFDM demodulation unit, and the decoding unit is temporarily stopped by a control signal from the communication unit. A digital broadcast receiver characterized by the above. The digital broadcast receiver according to claim 1,
The digital broadcast receiving apparatus according to claim 1, wherein the control signal is a signal that detects a state in which a transmission function of the communication unit shifts to an operation state. The digital broadcast receiver according to claim 1,
A detection unit that detects a state in which the transmission function of the communication unit shifts to an operation state, and temporarily or partially operates the channel selection unit, the analog-digital conversion circuit, the OFDM demodulation unit, and the decoding unit. A power control unit that automatically stops,
A digital broadcast receiving apparatus comprising: a control unit that synchronizes a transmission timing from the detection unit and a temporary stop of an operation by the power control unit. The digital broadcast receiver according to claim 1,
The digital broadcast receiver according to claim 1, wherein the control signal is a timing signal for roaming of the mobile terminal unit.

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