JP2004282774A - Digital broadcast receiving apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital broadcast receiving apparatus in which power consumption is efficiently reduced by stopping the operation of a broadcast wave receiving part in response to a transmitting operation of a communication means including a mobile terminal part. <P>SOLUTION: The digital broadcast receiving apparatus equipped with an antenna for receiving a broadcast wave of an orthogonal frequency division multiplex (OFDM) scheme includes a tuning means for tuning to a desired frequency band, an analog/digital conversion circuit for converting a tuned signal into a digital signal, an OFDM demodulation part for digital demodulation from the converted digital signal, a decoding part for performing decoding from the demodulated signal, a demux decoder part for decoding the information by performing demultiplexing from a decoded transport stream signal, and a communication means 32 for making possible mobile transmitting/receiving or portable transmitting/receiving services, and all or partial operations of the tuning part, the analog/digital conversion circuit, the OFDM demodulation part and the decoding part are temporarily stopped in response to a transmitting (roaming) signal 22 from the communication means 32. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique in which a digital broadcast receiving apparatus reduces power consumption of a digital broadcast receiving apparatus when a function other than a broadcast wave receiving function, for example, a transmitting unit of a portable terminal unit operates.

  In terrestrial broadcasting, digitization is performed in order to improve service by digitalization and to realize effective use of bandwidth by SFN (Singe Frequency 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 area. At the same time, high-quality broadcasting and data broadcasting services will be realized.

  Generally, in digital broadcasting, video / audio information as content information is compressed by the MPEG2 system, and data broadcasting is generated by a BML language by a recarousel transmission system. 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.

  In the case of terrestrial digital broadcasting, in Japan, a BST-OFDM (Band Segmented Transmission-Orthogonal Frequency Division Multiplexing) system is adopted, and this system is a multi-carrier transmission system using a plurality of carriers simultaneously, and each carrier is mutually used. They are orthogonal and are modulated by 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.

  In actual transmitters and receivers, 2K points to 8K points of I-DFT (Inverse-Discrete Fourier Transformation) processing and DFT (Discrete Fourier Transformation) processing are performed.

  In terrestrial digital broadcasting, unlike satellite broadcasting, a reflected wave is generated by an obstacle such as a building or a mountain, causing an error in a ghost and a redigital modulation signal. For this reason, the video and audio signals are broken in the receiver, and the reception quality is significantly degraded. In general, signal degradation due to noise can be corrected by error correction if the received signal satisfies the required C / N, and the receiver can reproduce video / audio without error.

  As described above, in order to absorb the influence of ghost or multipath interference, a buffer region is provided in the OFDM system so that even if a delayed wave is present, information is not broken. This buffer area is called a guard interval (GI). If the delay time of the delay wave of the received signal does not exceed the time of the guard interval, no code interference occurs, so that the error can be corrected by the error correction circuit. If the guard interval is exceeded, intersymbol interference will occur, causing 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 microseconds to 250 microseconds.

  Generally, in mobile reception or mobile reception in terrestrial broadcasting, a digitally modulated signal deteriorates due to multipath fading or the like, 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 for portable reception and mobile reception.

  FIG. 5 shows the configuration of a conventional receiver. A desired channel is selected from a signal from an antenna 11 for receiving a broadcast wave by a tuner 12 serving as a tuning unit and output. The selected and output IF signal is converted into a digital signal by the ADC 13 that performs analog-digital conversion. The IF signal converted to a digital signal is OFDM-demodulated by the OFDM demodulation unit 14, decoded by the decoding unit 15, and outputs a TS signal.

  The output TS signal is demultiplexed by the demux decoder 14, and the respective streams such as video / audio / data broadcast are output. Each of the separated signals undergoes information decoding processing and is 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 in which MPEG4 or the like is embedded, and enables viewing of still images, simple moving images, and the like.

  In digital terrestrial broadcasting, this mobile OFDM system enables high-quality mobile reception and portable reception services, and a new system can be constructed with a digital broadcast receiver (combined terminal) or the like in which a broadcast receiver is combined with communication means. .

  As described above, when services for mobile reception and mobile reception are performed in digital terrestrial broadcasting, digital broadcasting receivers can usually view contents such as video, audio, and data broadcasting, and communication means and In conjunction with this, new viewing forms and devices such as interactive services become possible. Such a digital broadcast receiving device (receiving terminal) is often operated by a battery, and its power consumption is desired to be reduced. For example, power consumption during roaming of the transmitting unit of the communication unit and continuous operation of the broadcast wave receiving unit overlap, thereby instantaneously increasing power consumption and increasing the load on the battery.

  In addition, when the digital broadcast receiving apparatus is viewing the content, in the case of data broadcasting, etc., when the information is repeatedly transmitted in the carousel, the information of the received content is completely viewed by performing a decoder process in that cycle. It is possible. For example, if the carousel has a 15-second cycle and is updated 3 minutes later, it will be repeatedly transmitted 12 times. At this time, if the information of one cycle can be completely obtained, the process of the broadcast wave receiving unit will continue to receive the same information This means that redundant operations are being performed.

  Therefore, in the digital broadcast receiving apparatus, when the content information is repeatedly transmitted, it is not necessary to set the receiving operation to the receiving operation in the normal state, and the operation can be completely or partially stopped. .

  In this way, power can be used efficiently and power consumption can be kept low even when the battery and power are limited, such as in a small digital broadcast receiver, and the operation of the digital broadcast receiver can be reduced. The operation time can be extended stably.

  In a digital broadcast receiving apparatus combined with a communication means such as a mobile phone, power is consumed by a transmission state of a roaming process or the like of the communication means, and a load on a battery is large when operations with a broadcast wave receiving unit occur simultaneously. And power consumption becomes significant.

  In order to solve such a problem, an object of the present invention is to provide a digital broadcast receiving apparatus that stops the operation of a broadcast wave receiving unit by a transmitting operation of a communication unit including a portable terminal unit and efficiently reduces power consumption. Is to provide. It is another object of the present invention to control the operation of a digital broadcast receiving apparatus according to the type of content information including data broadcast, thereby suppressing power consumption.

In order to solve the above problems, the present invention mainly employs the following configuration.
In a digital broadcast receiving apparatus including an antenna for receiving a broadcast wave based on orthogonal frequency division multiplexing (OFDM),
Tuning means for tuning a desired frequency band from a signal received by the antenna,
An analog-digital conversion circuit for converting a signal tuned by the tuning means into a digital signal;
An OFDM demodulator for digitally demodulating a signal digitally converted by the analog-digital conversion circuit;
A decoding unit for decoding from a demodulated signal demodulated by the OFDM demodulation unit;
A demux decoder section for demultiplexing (demuxing) the transport stream signal decoded by the decoding section and decoding information;
A broadcast control unit that detects a carousel acquisition state of the demux decoder unit;
The tuning unit, the analog-digital conversion circuit, the OFDM demodulation unit, comprising a power control unit for controlling the operation of the decoding unit,
The broadcast control unit sends a control signal based on a detection signal of the detected carousel acquisition state to the power control unit,
The power control unit receives the control signal and temporarily stops all or a part of the operation of the tuning unit, the analog-to-digital conversion circuit, the OFDM demodulation unit, and the decoding unit.

  In the digital broadcast receiving apparatus, the carousel acquisition state is a state in which acquisition of carousel data has been completed.

  Further, in the digital broadcast receiving apparatus, the power control unit determines in advance after stopping all or a part of the operation of the tuning unit, the analog-digital conversion circuit, the OFDM demodulation unit, and the decoding unit. The operation is started at predetermined intervals, and the interval can be changed.

  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, consumption is achieved by detecting the transmission state of the transmitting unit and stopping the receiving operation of the broadcast wave receiving unit. The power can be reduced.

  In addition, it is possible to reduce the power consumption by detecting the reception state of data broadcasting etc., stopping all or a part of the operation of the broadcast wave receiving unit after the carousel acquisition, and operating again at intervals. It is.

  A digital broadcast receiving apparatus 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 according to an embodiment of the present invention, which includes a portable terminal unit in addition to a broadcast wave receiving unit. 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 showing operation timings between the transmitting unit and the broadcast wave receiving unit of the mobile terminal unit. FIG. 4 is a diagram showing the operation timing of the broadcast wave receiving unit.

  In FIG. 1, first, the digital broadcast receiving apparatus 19 mainly includes a broadcast wave receiving unit 18 for receiving a broadcast wave, a portable terminal 32 (an example of a communication unit), and a control unit 21 for controlling operations of both. I have. Then, in the broadcast wave receiving unit 18 of the digital broadcast receiving apparatus 19 for receiving the broadcast wave transmitted from the broadcast station by the receiving antenna 11, the signal received by the antenna 11 is transmitted to the tuner 12 which is a tuning unit for tuning. To select the frequency you want to receive. The selected signal is converted into a re-digital signal by an analog-to-digital converter (ADC) 13 and demodulated by an OFDM demodulation unit 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).

  The transport signal is defined in the MPEG2-systems standard, and multiplexes video / audio / data broadcast and SI / PSI signals. The transport signal output from the decoding unit 15 is subjected to multiplex division processing by the demux decoder unit 16 and separated into content information such as video, audio, and data broadcast and control signals (SI / PSI signals) (filtering processing). ).

  The separated signals are subjected to decoding processing of the respective contents, and processed into viewable information. The video signal is subjected to MPEG2 decoding processing, and the audio signal is mainly subjected to AAC decoding processing. Data broadcasting performs carousel processing and displays information using a BML browser. It also processes information in which MPEG4 or the like is embedded, and enables viewing of still images, simple moving images, and the like.

  Then, voice and information are transmitted and received by the portable terminal unit 32 which is an example of the communication unit. Information from the microphone 28 is amplified by the amplifier 27, modulated and multiplexed 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 mobile terminal unit 32). Operation in the section). On the other hand, the signal received by the antenna 23 is amplified by the high-frequency amplifier 24, subjected to demodulation processing by the time division multiplexing 25 and the demodulation unit 29, amplified by the amplifier 30, and outputted from the speaker 31 (portable). Operation of the receiving unit of the terminal unit 32).

  The mobile terminal unit shown here shows a typical structure of a current mobile phone, but is not limited thereto, and may be, for example, a next-generation mobile phone (IMT200) that will appear in the future. . A similar effect can be expected with a PDA or the like having a transmission function.

  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 demodulation unit 14, and the decoding unit 15 in the broadcast wave receiving unit 18 are temporarily stopped to reduce the power consumption. For example, the tuner unit 12, the ADC 13, the OFDM demodulation unit 14, and the decoding unit 15 are controlled by the power control unit 20 of the broadcast wave receiving unit 18 via the control unit 21 according to the transmission state of the transmission control unit 22 in the portable terminal unit 32. The operation is temporarily stopped to suppress power consumption.

  Further, only the ADC 13, the OFDM demodulator 14, and the decoder 15 may stop the operation. Further, the operations of only the OFDM demodulator 14 and the decoder 15 may be stopped. Alternatively, only the operation of the decoding unit 15 may be stopped. The operation of the decoder units after the broadcast wave receiving unit may be stopped together with the stop of the broadcast wave receiving unit 18.

  When the operations of the OFDM demodulation unit 14 and the decoding unit 15 are stopped, the synchronization operation of the broadcast wave receiving unit 18 can be provided with continuity to enable quick operation recovery when the reception operation is recovered.

  FIG. 3 is a timing chart showing a typical operation in the broadcast wave receiving unit 18. Here, assuming that the portable terminal unit 32 performs transmission at an interval of about 640 ms for roaming or the like, the state is transmitted from the transmission control unit 22 to the power control unit 20 via the control unit 21 and the portable terminal unit 32 is transmitted. Is in the transmission state, the receiving operation of the broadcast wave receiving unit 18 is intermittently stopped. Based on a control signal from the power control unit 20, the operations of the tuner unit 12, the ADC 13, the OFDM demodulation unit 14, and the decoding unit 15 are temporarily or partially stopped to suppress power consumption.

  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, synchronized with the power control unit 20, the transmission timing for roaming is controlled, and the transmission timing and broadcast are transmitted. The operation of the wave receiving unit is exclusively performed, 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.

  Next, FIG. 2 shows a typical block diagram of another embodiment of the present invention. A signal from the antenna 11 for receiving a broadcast wave is extracted by the tuner 2 for selecting one wave of a desired frequency, and an IF signal is output. The output IF signal is converted into a digital signal by an analog-to-digital converter (ADC) 13 and demodulated by an OFDM demodulation unit 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). The transport signal is defined in the MPEG2-systems standard, and multiplexes video / audio / data broadcast and SI / PSI signals.

  The transport signal decoded by the decoding unit 15 is subjected to multiplex division processing by the demux decoder unit 16 to be divided into the content information (video / audio / data broadcast) and control signals (SI / PSI signals) (filtering processing). ). The demuxed signal is subjected to decoding of the content information by the decoder 16 to output a video signal, an audio signal, and a data broadcast.

  Among digital broadcasting, data broadcasting uses a carousel data transmission system, and the same information is periodically transmitted. In the digital broadcast receiving apparatus of the present invention, once the data broadcast information is obtained, it is not necessary to receive the data until the information is updated, and thus the receiving operation is temporarily stopped. The broadcast control unit 35 detects the carousel acquisition state of the demux decoder unit 16 and sends a control signal to the power control unit 20. The power control unit 20 operates the tuner 12, the ADC 13, the OFDM demodulation unit 14, and the decoding unit 15. Is temporarily or partially stopped to suppress power consumption.

  FIG. 4 is a timing chart showing a power control operation in data broadcasting. In the present invention, the power consumption accompanying the reception of the broadcast wave is suppressed by stopping the digital broadcast receiving operation for a predetermined period (interval). 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, the operation of the receiver is stopped to further save power.

  As described above, an overview of the operation of the embodiment of the present invention is as follows. 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. The operation of the broadcast wave receiving unit is stopped at the time of transmission for reply to the request, and the operation of the broadcast wave receiving unit is stopped and the operation is started at intervals after receiving the carousel at the time of receiving the data broadcast.

FIG. 1 is a diagram illustrating an overall configuration of a digital broadcast receiving device including a portable terminal unit in addition to a broadcast wave receiving unit according to an embodiment of the present invention. FIG. 11 is a diagram illustrating a power control configuration of a digital broadcast receiving device including a broadcast wave receiving unit according to another embodiment of the present invention. It is a figure showing operation timing between a transmitting part and a broadcast wave receiving part of a personal digital assistant. It is a figure showing operation timing of a broadcast wave receiving part. FIG. 1 is a diagram illustrating an entire configuration of a digital broadcast receiving device according to a conventional technique.

Explanation of reference numerals

11 Broadcast wave receiving antenna 12 Tuner 13 ADC
Reference Signs List 14 OFDM demodulation unit 15 Decoding unit 16 Demax decoder 17 Output terminal 18 Broadcast wave reception unit 19 Digital broadcast reception device 20 Power control unit 21 Control unit 22 Transmission control unit 23 Transmission / reception antenna 24 High frequency amplifier 25 Time division multiplex 26 Modulation unit 27 Amplifier 28 Microphone 29 Demodulation unit 30 Amplifier 31 Speaker 32 Portable terminal unit 40 Control unit

Claims (4)

In a digital broadcast receiving apparatus including an antenna for receiving a broadcast wave based on orthogonal frequency division multiplexing (OFDM),
Tuning means for tuning a desired frequency band from a signal received by the antenna,
An analog-digital conversion circuit for converting a signal tuned by the tuning means into a digital signal;
An OFDM demodulator for digitally demodulating a signal digitally converted by the analog-digital conversion circuit;
A decoding unit for decoding from a demodulated signal demodulated by the OFDM demodulation unit;
A demux decoder section for demultiplexing (demuxing) the transport stream signal decoded by the decoding section and decoding information;
A broadcast control unit that detects a carousel acquisition state of the demux decoder unit;
The tuning unit, the analog-digital conversion circuit, the OFDM demodulation unit, comprising a power control unit for controlling the operation of the decoding unit,
The broadcast control unit sends a control signal based on a detection signal of the detected carousel acquisition state to the power control unit,
The power control unit receives the control signal, and temporarily stops the operation of all or a part of the tuning unit, the analog-digital conversion circuit, the OFDM demodulation unit, and the decoding unit. Digital broadcast receiving device.   The digital broadcast receiving apparatus according to claim 1, wherein the carousel acquisition state is a state in which acquisition of carousel data has been completed.   The power control unit stops the operation of all or a part of the tuning unit, the analog-digital conversion circuit, the OFDM demodulation unit, and the decoding unit, and then starts the operation at a predetermined interval. 3. The digital broadcast receiving apparatus according to claim 1, wherein   The digital broadcast receiving device according to claim 3, wherein the interval is changeable.

Images