JP4135252B2 - Receiver - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data transmission / reception method and a reception apparatus for changing a reception frequency in response to a change or addition of a transmission frequency in a data transmission / reception system.
[0002]
[Prior art]
Currently, the digitization of television broadcasting is rapidly progressing worldwide. In Japan, digital broadcasting using a communication satellite (CS) is started in 1996, and digital broadcasting using a broadcasting satellite (BS) is scheduled to start in 2000. In these satellite broadcast receivers, the frequencies to be used are determined in advance, and in the receiver, a correspondence list of these physical channel numbers (transponder numbers in the case of satellites) and reception frequencies is stored in a memory or the like in advance. Based on this, the physical channel is switched.
[0003]
[Problems to be solved by the invention]
On the other hand, terrestrial broadcasting is also digitized, the service is scheduled to start in 2003, and the current analog broadcasting is scheduled to be abolished in 2010. Terrestrial digital broadcasting is broadcast using the current analog broadcasting vacant channel at the beginning of the service. Furthermore, it is expected that the frequency reassignment is performed such that the frequency currently used in the analog broadcast is also sequentially assigned to the digital after the abolition of the analog broadcast. There is also a possibility that a new frequency will be added to digital broadcasting.
[0004]
Frequency reassignment and addition are likely to be performed sequentially in time series, and the frequency to be reassigned or added to the receiver memory etc. from the time of shipment of the initial digital broadcast receiver is stored. Have difficulty.
[0005]
Therefore, when the frequency reassignment or addition is performed, the transmission side informs the digital broadcast receiver side, and the receiver side immediately responds to the frequency reassignment or addition and broadcasts a new frequency. Must be able to receive.
[0006]
The present invention has been made to solve such problems. In the transition period from analog broadcasting to digital broadcasting, the digital broadcast receiver side is notified of frequency reassignment and frequency addition, and the receiver side It is an object of the present invention to provide a data transmission / reception method and a receiving apparatus that can cope with the change.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the receiving apparatus of the present invention, the frequency change information extracting a frequency change information used to receive a new reassignment or additional frequency from the transport stream obtained from the radio wave of the received frequency extracting means and a changing frequency storing means constituted by the extracted non-volatile memory for outputting storing the frequency change information, changing the time extracting means for extracting a use start time of the frequency change information from the transport stream A change time storage means for storing and outputting the use start time of the extracted frequency change information, a reception frequency storage means for storing a frequency used for reception, and a clock means for measuring and outputting the time in the reception apparatus And the output of the clock means and the use start time of the frequency change information which is the output of the change time storage means A comparison means for outputting a signal for loading the frequency change information, which is the output of the change frequency storage means, into the reception frequency storage means when the output of the clock means reaches the output of the change time storage means; Prepare.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
(Embodiment 1)
FIG. 1 shows a method for transmitting frequency change information in a data transmission / reception method according to Embodiment 1 of the present invention. In the description of the embodiment, a digital broadcasting system is taken as an example, and it is divided into a transmission side and a reception side.
[0019]
On the transmission side in the digital broadcasting system, first, video and audio data are subjected to high-efficiency encoding and compression in accordance with the MPEG2 standard, and converted into a digital stream. This is packetized by adding control data (header), and is multiplexed into a transport packet of 1 packet = 188 bytes. In addition to video packets and audio packets, program arrangement information necessary for program selection at the receiver and electronic program guide is packetized and multiplexed in this transport packet.
[0020]
In the present invention, frequency change information is multiplexed on this transport stream. The receiver takes in this frequency change information and changes the setting of the reception frequency. The configuration and operation of the receiver of the present invention will be described later. The frequency change information of the present invention includes a frequency that is newly used from a certain time and a time at which the new frequency starts to be used.
[0021]
The frequency change information is stored, for example, in a descriptor (descriptor) of NIT (Network Information Table) defined by the program arrangement information (ARIBSTD-B10, “Program arrangement information used for digital broadcasting” 1997). Here, FIG. 2 shows a data structure of NIT defined by ARIB, and FIG. 3 shows an example of a descriptor for storing frequency change information of the present invention.
[0022]
For the description of NIT, refer to the ARIB standard described above. Here, a descriptor for storing frequency change information will be described with reference to FIG. The name of this descriptor is assumed to be a frequency change descriptor (frequency # change # descriptor). Of course, other names may be used.
[0023]
Next, the meaning of the contents of the descriptor will be described. descriptor # tag and descriptor # length are fields used for the descriptor format specified in the MPEG2 system standard (ISO / IEC13818-1). In the present invention, the descriptor stores frequency # change # time as the time to change the frequency and new # frequency as the frequency to be newly used.
[0024]
For example, 40-bit JST # time used in TDT (Time and Date Table) may be used as frequency_change # time. For the JST # time encoding method, refer to the above ARIB standard.
[0025]
Next, the configuration and operation of the receiving apparatus of the present invention will be described. FIG. 4 shows the configuration of the receiving apparatus of the present invention. In FIG. 4, reference numeral 10 denotes a receiving unit that receives radio waves, and receives the radio waves and outputs a bit stream. This consists of an antenna and a tuner. Reference numeral 11 demodulates the bit stream digitally modulated by the demodulator, performs error correction, and reproduces the transport packet.
[0026]
12 is a demultiplexer that extracts a program selected by a viewer, a packet arrangement information, and a packet containing frequency change information from a transport stream multiplexed with video packets, audio packets, program arrangement information, frequency change information, and the like. It is. The extraction of the frequency change information will be described in detail later.
[0027]
A video decoding unit 13 decodes the compressed video packet extracted by the demultiplexing unit 12. Reference numeral 14 denotes a first digital / analog conversion unit for converting the decoded digital video data into an analog signal.
[0028]
An image display unit 15 is, for example, a CRT or a liquid crystal display. An audio decoding unit 16 decodes the compressed audio packet extracted by the demultiplexing unit 12. Reference numeral 17 denotes a second digital / analog conversion unit for converting the decoded digital audio data into an analog signal.
[0029]
Reference numeral 18 denotes an audio output unit such as a speaker. A control unit 19 controls the entire receiving apparatus of the present invention. The point of the present invention resides in this control unit.
[0030]
The configuration of the control unit 19 will be described in detail. FIG. 5 shows an internal configuration of the control unit 19. In FIG. 5, reference numeral 101 denotes a frequency change information extraction unit which extracts frequency change information, that is, a newly used frequency, from a packet including the frequency change information extracted by the demultiplexing unit 12. Reference numeral 102 denotes a changed frequency storage unit which stores a list of frequencies to be newly used, and needs to be realized by a nonvolatile memory or the like so that information is not lost even when the power of the receiving apparatus is turned off. A change time extraction unit 103 extracts a time when a frequency starts to be newly used from a packet including frequency change information extracted by the demultiplexing unit 12.
[0031]
A change time storage unit 104 stores the change time. The change time storage unit 104 needs to be realized by a non-volatile memory or the like so that the stored change time is preserved even when the power of the receiving apparatus is turned off.
[0032]
A clock unit 105 measures the time in the receiving apparatus. A comparison unit 106 compares the clock change times stored in the clock unit 105 and the change time storage unit 104 and outputs a load enable signal if they match.
[0033]
A reception frequency storage unit 107 associates a frequency used for reception with a physical channel number.
[0034]
Here, the physical channel number means a channel number that has a one-to-one correspondence with a physical frequency. The reception frequency storage unit 107 also needs to be configured with a nonvolatile memory. A specific operation of the receiving apparatus of the present invention configured as described above will be described below.
[0035]
The operations of the receiving unit 10 and the demodulating unit 11 are as described above. Here, the operations of the demultiplexing unit 12 and the control unit will be described in detail.
[0036]
It is assumed that the frequency change information is multiplexed on the NIT and transmitted on the transmission side. FIG. 6 shows a processing flow of the receiving apparatus. In the description of the embodiment, it is assumed that the frequency change information is multiplexed in the NIT. The following processing flow is divided into steps.
[0037]
Step 1: NIT is extracted by the demultiplexing unit.
[0038]
Step 2: The frequency change information extraction unit 101 extracts a frequency change descriptor from the NIT.
[0039]
Step 3: A frequency value newly used by the frequency change information extraction unit 101 is extracted.
[0040]
Step 4: The newly used frequency is stored in the changed frequency storage unit 102.
[0041]
Step 5: The change time extraction unit 103 extracts the use start time of the new frequency.
[0042]
Step 6: Use start time is stored in the change time storage unit 104.
[0043]
Step 7: The time measured by the clock 105 is compared with the use start time.
[0044]
In comparison, the process returns to step 7 while the time of the clock does not reach the use start time. On the other hand, if the time of the clock reaches the use start time, the process goes to step 8.
[0045]
Step 8: Output a load enable signal from the comparison unit 106, load a new frequency to be used from the changed frequency storage unit 102 to the use frequency storage unit 107, and store it in the use frequency storage unit.
[0046]
As described above, according to the present embodiment, on the transmitting side, the frequency to be newly used and the time to start using are stored in the frequency change information descriptor, multiplexed and transmitted to the NIT, and on the receiving side. After receiving, demodulating, and error correcting processing, a step of extracting NIT by the demultiplexing unit, a step of extracting the frequency change descriptor by the frequency change information extracting unit, and a new use by the frequency change information extracting unit A step of extracting the frequency, a step of storing the new frequency in the changed frequency storage unit, a step of extracting the use start time in the new frequency by the change time extracting unit, and a step of storing the use start time in the changed time storage unit 104 And the step of comparing the time measured by the clock with the use start time, and if the clock time reaches the use start time, a load enable signal is output from the comparison unit 106 and changed. Receiving a newly used frequency from the wave number storage unit to the reception frequency storage unit, and storing the frequency in the reception frequency storage unit, so that the digital broadcast reception from the transmission side during the transition to digital broadcasting The frequency reassignment or frequency addition is notified to the device, and the receiver can respond to the change of the frequency and receive the broadcast of the new frequency.
[0047]
In this embodiment, the frequency change information is multiplexed on the NIT. However, the frequency change information may be multiplexed not on the NIT but on the program arrangement information included in the transport stream, or may be multiplexed as a PES packet, or in the MPEG. It may be multiplexed in the area defined as private. In the present embodiment, the frequency change information is stored in a format called a descriptor, but it may be stored in another format without being stored in the descriptor area.
[0048]
(Embodiment 2)
Next, a second embodiment of the present invention will be described. In the second embodiment, the method for transmitting frequency change information is the same as that in the first embodiment, but the frequency change information does not include a frequency value but includes only the time at which the frequency is changed. FIG. 8 shows a frequency change descriptor in the second embodiment. Since the transmitting side is the same except for the contents of the frequency change descriptor of the first embodiment, description thereof is omitted.
[0049]
Since the configuration and operation of the control unit are different on the receiving side, the control unit will be described. FIG. 8 shows the configuration of the control unit of the second embodiment. The same components as those in the first embodiment are denoted by the same reference numerals. Reference numeral 201 denotes a frequency scanning unit that scans frequencies in a receivable frequency region and extracts a frequency at which received power or received electric field strength has a maximum value.
[0050]
A control unit 202 activates the frequency scanning unit 201 according to the comparison result of the comparison unit. The operation of the second embodiment will be described below.
[0051]
Also in the second embodiment, description will be made assuming that the frequency change information is multiplexed and transmitted on the NIT on the transmission side. FIG. 9 shows a processing flow of the receiving apparatus. The following processing flow is divided into steps.
[0052]
Step 21: NIT is extracted by the demultiplexing unit.
[0053]
Step 22: The frequency change information extraction unit 101 extracts the frequency change descriptor from the NIT. Step 23: The change time extraction unit 103 extracts the use start time of the new frequency.
[0054]
Step 24: Use start time is stored in the change time storage unit 104.
[0055]
Step 25: The time measured by the clock 105 is compared with the use start time.
[0056]
In comparison, while the time of the clock does not reach the use start time, the process returns to step 25. On the other hand, if the time of the clock reaches the use start time, the process goes to step 26.
[0057]
Step 26: If the comparison result in Step 25 is “arrival”, the control unit 202 activates the frequency scanning unit 201. The frequency scanning unit 201 detects a frequency having a maximum value of electric power or electric field strength of received radio waves.
[0058]
Step 27: Store the frequency detected in step 26 in the reception frequency storage unit 107.
[0059]
As described above, according to the present embodiment, the transmission side newly stores the time at which the use of the frequency is started in the frequency change descriptor, is multiplexed and transmitted to the NIT, and is received on the reception side. After performing demodulation and error correction processing, a step of extracting NIT by the demultiplexing unit, a step of extracting a frequency change descriptor by the frequency change information extracting unit, a step of storing a new frequency in the changed frequency storage unit, and a change A step of extracting the use start time to the new frequency by the time extraction unit; a step of storing the use start time by the change time storage unit 104; a step of comparing the time measured by the clock with the use start time; and the time of the clock When the use start time is reached, a frequency scan is performed to detect a frequency having a maximum value of received power or received electric field strength and store the frequency in the received frequency storage unit. Therefore, during the transition to digital broadcasting, the sending side notifies the digital broadcasting receiver of the time at which frequency reassignment or frequency addition is performed, and the receiver side responds to the frequency change. It becomes possible to receive broadcasting of a new frequency.
[0060]
In this embodiment, the frequency change information is multiplexed on the NIT. However, the frequency change information may be multiplexed not on the NIT but on other program arrangement information of the transport stream, or may be multiplexed as a PES packet, or in the MPEG. It may be multiplexed in the area defined as private.
[0061]
In the present embodiment, the frequency change information is stored in a format called a descriptor, but it may be stored in another format without being stored in the descriptor area. The present invention is applicable not only to terrestrial digital broadcasting but also to other media such as satellite broadcasting and CATV.
[0062]
【The invention's effect】
As described above, according to the data transmission / reception method of the present invention, the transmission side transmits data storing the frequency to be newly used by modification or addition and the time when the use is started, and the reception side uses the changed frequency and the use thereof. When the start time is detected and the use start time is reached, the frequency is reassigned or added to the digital broadcast receiver from the transmission side during the transition to digital broadcasting by setting the reception frequency. The time is notified, and the receiver can respond to the frequency change and receive a broadcast of a new frequency.
[Brief description of the drawings]
FIG. 1 is a diagram showing frequency change information multiplexed in a transport stream. FIG. 2 is a diagram showing a data structure of NIT. FIG. 3 is a diagram showing a data structure of a frequency change information descriptor in the first embodiment. 4 is a diagram illustrating a configuration of a receiving device. FIG. 5 is a diagram illustrating a configuration of a control unit in the first embodiment. FIG. 6 is a diagram illustrating a process flow in the first embodiment. FIG. 7 is a frequency in the second embodiment. FIG. 8 is a diagram showing a data structure of a change descriptor. FIG. 8 is a diagram showing a configuration of a control unit in the second embodiment. FIG. 9 is a diagram showing a processing flow in the second embodiment.
DESCRIPTION OF SYMBOLS 10 Reception part 11 Demodulation part 12 Demultiplexing part 13 Video decoding part 14 Digital analog conversion part 15 Video display part 16 Audio | voice decoding part 17 Digital analog conversion part 18 Audio | voice output part 19 Control part 101 Frequency change information extraction part 102 Change frequency memory | storage part 103 Change Time Extraction Unit 104 Change Time Storage Unit 105 Clock Unit 106 Comparison Unit 107 Reception Frequency Storage Unit 201 Frequency Scan Unit 202 Control Unit

Claims (1)

And the frequency change information extraction means for extracting the frequency change information used to receive the new reassignment or additional frequency from the transport stream obtained from the radio wave of the received frequency,
Change frequency storage means configured by a non-volatile memory that stores and outputs the extracted frequency change information;
And changing the time extracting means for extracting a use start time of the frequency change information from the transport stream,
Change time storage means for storing and outputting the use start time of the extracted frequency change information;
A reception frequency storage means for storing a frequency used for reception;
Clock means for measuring and outputting the time in the receiving device;
The output of the clock means is compared with the use start time of the frequency change information which is the output of the change time storage means, and when the output of the clock means reaches the output of the change time storage means, the change frequency storage A comparison means for outputting a signal for loading the frequency change information, which is an output of the means, into the reception frequency storage means;
A receiving apparatus.

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