JP2002218339A - Digital broadcast receiver - Google Patents

Abstract

(57) [Summary] [PROBLEMS] A receiver corresponding to a terrestrial digital broadcasting system for transmitting using various transmission parameters, by referring to a reception area-transmission parameter correspondence table stored in advance from reception area information. To be able to successfully perform initial tuning and obtain new transmission parameters. SOLUTION: A channel selecting means, a means for decoding an OFDM frame transmitted by using a terrestrial digital broadcasting transmission system, and a TMC having transmission parameters multiplexed therein.
Means for decoding the C section, receiving area search means for inputting the area where the viewer is receiving and detecting the receiving area, means for controlling the demodulation parameter to act to use for tuning and decoding, and demodulation. Means for storing parameters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcast receiver such as a terrestrial digital broadcast receiver, and more particularly to an ISD.
BT (Integrated Services Digital Broadcasting-
TN) transmission method and SFN (Single Freqency Ne)
The present invention relates to a digital broadcast receiver suitable for use in reception of a broadcast system / operation system adopting a network configuration in which two network devices such as twork) and MFN (Multi Frequency Network) are mixed.

[0002]

2. Description of the Related Art Conventional terrestrial broadcasting is transmitted by NTSC, and the transmission mode is transmitted in only one mode.
That is, a luminance signal and two color difference signals are separated, a chrominance signal is represented by a chrominance subcarrier, and amplitude modulation is performed by a quadrature two-phase modulation method using a carrier whose carrier is suppressed. Is inserted. Furthermore, frequency use efficiency is improved by frequency interleaving.

On the other hand, the terrestrial digital broadcasting system is an OFDM (Orthogonal Frequency Division Multip
lex; orthogonal frequency division multiplexing), that is, BST-OFD
M (Band Segmented Transmisson-OFDM). This OFDM is a hierarchical transmission scheme in which a transmission band is divided into small segment groups, each group is subjected to transmission path coding with required parameters, and a plurality of transmissions having different degradation tolerances are possible. These configurations are performed based on the organization information of a program, and this organization information is used as a control signal for hierarchical transmission and is used as a transmission and multiplexing (TMCC).
Configuration Control; transmission and multiplexing control) signals are transmitted to the receiver. Furthermore, with the introduction of terrestrial digital television broadcasting, the current analog broadcasting UH
Use the F-band free channel and use the frequency effectively.
A single frequency network is planned for each broadcast area. However, in order to minimize the effects of various types of interference, etc., and to ensure a correct reception rate,
The introduction of multiple frequency networks is also envisioned.

[0004] The receiver converts network information and transmission control signal information of a receiving area into TMCC or NIT (Netw
ork Information Table; network information table)
Can be received and decoded and detected correctly,
Until the initial state, that is, the initial tuning succeeds, the reception area, the reception network information, and the transmission control information cannot be detected. How to tune quickly in the initial state is an important receiving performance, and since it is before the introduction, etc., methods and procedures related to the optimal initial tuning in consideration of the network of each broadcasting area have been proposed before. Absent.

[0005]

In the above-mentioned initial state, various control signals for hierarchical transmission performed based on the program information are prepared and stored in a receiver in advance, and after tuning based on them, , Receive and refer to TMCC signals and update various control signals of hierarchical transmission performed based on the program information held in advance, so that the next tuning and after will be started preferentially based on the transmission mode. By doing so, it is possible to tune quickly. The problem is how to receive and update information of various control signals of hierarchical transmission performed based on the program information of the program in the receiver.

Furthermore, with the introduction of terrestrial digital television broadcasting, it is planned to use a UHF band free channel of the current analog broadcasting and to construct a single frequency network for each broadcasting area for effective use of frequency. However, a plurality of frequencies may be used instead of a single frequency to avoid the influence of interference or the like for each broadcast area.
In addition, when the reception area is changed due to reception while moving, moving, or the like, it is necessary to promptly detect not only the transmission mode but also the mode of the current reception area from the frequency information included in the NIT. Currently, only representative information is planned for the network information described in the NIT, and it is highly likely that the frequency or the like detected when actually tuned is different from the frequency information or the like described in the stream. Therefore, realization of a means for managing these two frequency information is also an issue. Basically, the receiver tunes based on the NIT information, so it is necessary to correlate the NIT information with the actually tuned information and use it for the next tuning. Furthermore, reception at a mobile unit changes every time the reception area changes, so that seamless reception cannot be realized unless such information is updated to the reception area that changes sequentially. Therefore, the realization of a method for specifying the receiving area is also an issue.

[0007]

An outline of the means for solving the above-mentioned problems is as follows.

First, a reception frequency and transmission specification correspondence table in various parts of the country previously notified is stored in advance. The receiver detects the receiving area when the user inputs the postal code or the area setting. The receiver refers to the receivable frequencies and transmission specifications in the reception area from the reception area information input by the user and the reception frequencies and transmission specification correspondence tables in various parts of the country, and uses them for initial tuning. If the tuning is successful, the reception area information, the reception frequency information, and the mode guard interval information are associated and updated and stored. If the tuning is not successful, one of the mode and the guard interval is tried without changing the reception frequency, and the tuning operation is performed. Further, if the tuning is not successful, the frequency of the nearby service area is selected from the reception frequency and transmission specification correspondence table in various parts of the country, and the tuning operation is repeated. When the tuning is successful in the above procedure, in any case, the reception area information, the reception frequency information, and the mode guard interval information are associated and updated and recorded. If the tuning is not successful, it is determined that the signal cannot be received due to the direction of the antenna or the reception failure, and the receiver is notified of the fact. Further, if tuning is successful, the demodulated digital signal (MPEG-
TS), a network information table (NIT) is separated, and a reception frequency and a service list are detected from the information. At this time, depending on the receiving area, it is planned to construct a single frequency network.However, in order to minimize the effects of various interference interference and secure the correct reception rate, some The introduction of a network is also envisioned. Therefore, when a plurality of frequencies are used, the frequency of the master station and the frequency of the relay station may be different, and the frequency actually tuned and synchronized differs from the frequency described in the NIT. In such a case, a means for separately storing the frequency difference is provided, and the reception area, the reception frequency, the transmission control information,
It is necessary to associate and store NIT information and the like.
Further, from the network information described in the NIT, the tuning operation is performed at all receivable frequencies, and the receiving frequency and the transmission control information at the time of successful tuning are associated and updated and stored in the receiver. For the tuning after the next time, the tuning control is performed based on the stored fixed information. Further, when the reception area is moved, the corresponding information of the reception frequency and the transmission control signal at the time of successful tuning in the service area stored in the receiver cannot be used, and it is necessary to newly acquire the corresponding information. At this time, it is determined that the transmission control information of each broadcaster has a correlation nationwide, and the tuning operation is started by preferentially using the stored transmission control information other than the reception frequency. By this operation, tuning can be completed relatively quickly. That is, information on the received area is sequentially updated and stored from the reception frequency and transmission specification correspondence table nationwide, and the initial tuning when moving to other areas is updated with the frequency based on this correspondence table. The operation starts from the transmission control signal for each broadcaster. On the other hand, another means, for example, a means for taking in a receiving frequency and a transmission specification correspondence table in various parts of the country and a receiving frequency and a transmission specification correspondence table of the receiving area into a receiver via a modem may be provided. Furthermore, when receiving terrestrial digital broadcasts while riding on a mobile object such as an automobile, the receiving area changes every moment. Therefore, as a means for sequentially identifying the receiving area, it is linked with an automatic positioning system mounted on the automobile or the like. It is also conceivable to specify the receiving area. And
According to the reception area specified by the above-described means, by switching the frequency and transmission control signal, by performing tuning control,
It is possible to receive and view seamlessly even in a moving object.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

First, prior to the description of each embodiment of the present invention, a standard terrestrial digital broadcast receiver will be described. FIG. 1 is a block diagram showing a configuration example of a standard terrestrial digital broadcast receiver. In FIG. 1, reference numeral 1 denotes a channel selection unit, 2 denotes an OFDM demodulation / decoding unit, 3 denotes a demultiplexing unit, and 4 denotes an information source. It is a decoding unit.

In the configuration shown in FIG. 1, a broadcast wave transmitted in the UHF band is input to a tuning unit 1 via an antenna. The tuning unit 1 tunes to the frequency of a broadcast wave that can be received or desired to be received, extracts only the desired wave, and
Output to the DM demodulation / decoding unit 2. The OFDM demodulation / decoding unit 2 converts an analog signal into a digital signal,
Demodulation and frequency / time deinterleaving are performed via FT (fast Fourier transform). In the case of hierarchical transmission, modulation division is performed, demapping is performed based on each modulation scheme, and then combined again to perform bit deinterleaving / bit deinterleaving.
Depuncture. Finally, it performs Viterbi decoding, byte deinterleaving, energy diffusion removal, and MPEG
After reproducing the TS, the error is corrected by the outer code. On the other hand, in order to decode the transmission control signal, the OFDM frame is decoded, and the transmission control signal portion is determined and extracted. The main transmission control signals multiplexed are as follows. That is, system identification (wideband / narrowband ISDB
-T), carrier modulation method (DQPSK / QPSK / 1)
6QAM / 64QAM), convolutional coding rate (1 /
2, 2/3, 3/4, 5/6, 7/8), an interleaving method (time interleaving configuration), and the like. It is necessary to execute a demodulation operation based on this transmission control signal. However, this transmission control signal is a signal that can be detected after the broadcast wave has been received, tuned and demodulated, and cannot be used at the time of initial tuning. Therefore, how quickly the initial tuning succeeds is an important function.

The error-corrected MPEG-
The TS (hereinafter, referred to as TS) is supplied to the demultiplexing unit 3 as a bit stream. The demultiplexing unit 3 separates a video signal and an audio signal to be viewed, program arrangement information, and the like, and performs decoding and control based on the arrangement information. In particular, an NIT in which information of a terrestrial network is described in the program arrangement information will be described. Within the NIT is a terrestrial distribution system descriptor that describes information about the terrestrial distribution system. The descriptor describes an area code (specifying a service area), a guard interval, mode information, frequency information, and the like. Each of these is important information used in channel selection and OFDM demodulation. When tuning, if this information is incorrect, there is a possibility that the information cannot be permanently received. However, this NIT is also tuned, OFDM,
Unless demodulation is successful, detection and decoding cannot be performed. When tuning in the initial tuning, the NIT information is compared with the actually tuned parameters,
It needs to be controlled.

[0013] The video / audio to be viewed is output from the demultiplexing section 3 to the information source decoding section 4. In the information source decoding unit 4, the video signal and the audio signal encoded by MPEG are decoded and presented by the presentation device.

Next, each embodiment of the present invention will be described. FIG. 2 is a block diagram showing a main configuration of the digital terrestrial broadcast receiver according to the first embodiment of the present invention. FIG.
, 1 is a tuning unit, 5 is an ADC (A / D conversion unit),
6 is an OFDM frame decoding unit, 7 is a TMCC decoding unit, 8 is a reception area search unit, 9 is a demodulation parameter control unit,
Reference numeral 10 denotes a demodulation parameter storage unit. 2 shows only functional blocks related to the gist of the present invention for the sake of simplicity of description, but the receiver of the present embodiment also has the same function as the receiver shown in FIG. (This is the same in the following embodiments).

In the configuration shown in FIG. 2, the tuning section 1 tunes to the frequency of a broadcast wave that can be received or desired to be received, and extracts only a desired wave. At this time, for example, a reception frequency and transmission specification correspondence table in various parts of the country that have been announced in advance are stored in the demodulation parameter storage unit 10 in advance. Furthermore, in order for the viewer to input the reception area by region setting or zip code, and to associate the information with the reception frequency and transmission specification correspondence table nationwide, the reception area search unit 8 conforms to the correspondence table. To the specified region code. The converted code is input to demodulation parameter control section 9. The demodulation parameter control unit 9 extracts the reception frequency and transmission data of the matched area from the demodulation parameter storage unit 10 based on the code, sets them in the channel selection unit 1 and the OFDM frame decoding unit 6, and performs initial tuning and demodulation. Start operation.
From the signal demodulated based on this information, the TMCC decoding unit 7
The demodulation parameter control unit 9 compares the extracted information with the information in the demodulation parameter storage unit 10 and updates the information in the demodulation parameter storage unit 10 if they are different. I do. Further, if the demodulation parameter storage unit 10 has other frequencies and transmission specifications in the matched area, tuning and demodulation are repeated for all combinations, and each time the TMCC decoding unit 7 modulates and transmits other transmission specifications. Then, the extracted information is compared with the information in the demodulation parameter storage unit 10, and if they are different, the information in the demodulation parameter storage unit 10 is updated.

FIG. 3 is a block diagram showing a main configuration of a terrestrial digital broadcast receiver according to a second embodiment of the present invention. In FIG. (This is the same in the following embodiments). In FIG. 3, 11 is an OFDM decoding unit, 12 is a multiplexing / demultiplexing unit, and 13 is a frequency difference storage / conversion unit.

In the configuration shown in FIG. 3, the tuning unit 1 tunes to the frequency of a broadcast wave that can be received or desired to be received, and extracts only a desired wave. At this time, for example, a reception frequency and transmission specification correspondence table in various parts of the country that have been announced in advance are stored in the demodulation parameter storage unit 10 in advance. Furthermore, in order for the viewer to input the reception area by region setting or zip code, and to associate the information with the reception frequency and transmission specification correspondence table nationwide, the reception area search unit 8 conforms to the correspondence table. To the specified region code. The converted code is input to demodulation parameter control section 9. The demodulation parameter control unit 9 extracts the reception frequency and transmission data of the matched area from the demodulation parameter storage unit 10 based on the code, sets them in the channel selection unit 1 and the OFDM frame decoding unit 6, and performs initial tuning and demodulation. Start operation.
From the signal demodulated based on this information, the TMCC decoding unit 7
The demodulation parameter control unit 9 compares the extracted information with the information in the demodulation parameter storage unit 10 and updates the information in the demodulation parameter storage unit 10 if they are different. I do. Further, if the demodulation parameter storage unit 10 has other frequencies and transmission specifications in the matched area, tuning and demodulation are repeated for all combinations, and each time the TMCC decoding unit 7 modulates and transmits other transmission specifications. Then, the extracted information is compared with the information in the demodulation parameter storage unit 10, and if they are different, the information in the demodulation parameter storage unit 10 is updated.

On the other hand, in each tuning operation, the bit stream reconstructed by the OFDM
The signal is input to the FDM decoding unit 11, and the OFDM decoding unit 11 decodes the terrestrial digital broadcast transmission channel coding method,
Extract the TS signal. This TS signal is transmitted to the multiplexing / demultiplexing unit 1
2. In the program arrangement information, a terrestrial distribution system descriptor describing the information of the terrestrial distribution system in the NIT describing the information of the terrestrial network is detected, and the area code (specifying the service area) is input. ), Guard interval, mode information, and frequency information. From this information, a guard interval, mode information, and a reception frequency when the area input by the receiver matches this area information are extracted and stored in the demodulation parameter storage unit 10 via the demodulation parameter control unit 9. Check with other frequencies. If the information described in the NIT is different from the storage information, the frequency difference storage / conversion unit 13
This difference information is stored at the next time, and at the time of the next channel selection, based on the difference information, the frequency described in the NIT is used.
The frequency is converted into an actually tunable frequency, and the tuning unit 1 and the OFDM frame decoding unit 6 are controlled via the demodulation parameter control unit 9. The difference information is stored only in the area code / area code obtained by converting the reception area set by the viewer in the reception area search unit 8 out of all the parameters for each reception area described in the NIT. Remember.

Next, a description will be given of a case where the receiving area is changed due to moving or the like. If you move in the receiving area because of moving or other reasons, ask the viewer to enter the receiving area again by region setting or zip code, and associate the information with the receiving frequency and transmission specification correspondence table all over the country, The receiving area search unit 8 converts the area code into an area code suitable for the correspondence table. The converted code is input to demodulation parameter control section 9. Based on this reception area, FIG. 2 or FIG.
Starts the operation described in the above, but assuming that transmission parameters are relatively unified for each carrier throughout the country, it detects the part changed from the previous record and the changed transmission data. , Preferentially enters the initial tuning from the transmission specifications. By such operation control, tuning can be performed more quickly than the operation described in FIGS.
Acquisition of information is also performed smoothly.

FIG. 4 is a block diagram showing a main configuration of a terrestrial digital broadcast receiver according to a third embodiment of the present invention. In FIG.
It is a data conversion unit.

The basic operation of this embodiment is the same as that of the first embodiment, but this embodiment is a specific example of how to acquire information stored in the demodulation parameter storage unit 10. . The receiver accesses the server where the trader stores the latest reception frequency and transmission specification correspondence table in various parts of the country without forcing or as desired. That is, the host server is accessed via the modem 14, and the reception frequency and transmission specification correspondence table in various parts of the country are extracted. The reception frequency and transmission specification correspondence table in various parts of the country
5 is converted to a format to be stored in the demodulation parameter storage unit 10 and stored. In the digital broadcast receiver, since the installation of a modem is almost an essential function, an example in which the modem is used and acquired has been described.

As an alternative to the modem, a download method may be used, and a correspondence table or an update difference may be distributed by broadcast waves, and these may be sequentially collected and updated. In this way, it is possible to construct a receiving system that can follow even if the introduction area is sequentially changed or updated.

FIG. 5 is a block diagram showing a main configuration of a terrestrial digital broadcast receiver according to a fourth embodiment of the present invention. In FIG. 5, reference numeral 16 denotes an automatic positioning system, and 17 denotes a reception area detection unit. is there. Here, the automatic positioning system 16
May be provided in a receiver, but here, a system mounted on an automobile or the like is used.

The basic operation of this embodiment is the same as that of the first embodiment. However, in this embodiment, when the user is moving on a moving body, for example, a car or the like, he or she sequentially moves while moving. When the reception area cannot be clearly determined or when the change of the reception area cannot be successively performed, the reception area is automatically determined by linking with the automatic positioning system 16 mounted on an automobile or the like and reflected in the reception operation. By
This enables seamless reception. That is, the position information is supplied to the reception area detection unit 17 from the automatic positioning system 16 mounted on the moving body. The reception area detection unit 17 converts the position information into an area code and an area code, extracts various parameters of a desired area from the demodulation parameter storage unit 10 via the demodulation parameter control unit 9, and uses them for channel selection and demodulation. . By this operation sequence, the reception area can be detected and specified in real time by linking with the automatic positioning system 16 even while moving with the mobile body, and optimal tuning and demodulation can be performed as appropriate.

[0025]

According to the first aspect of the present invention, based on the information on the receiving area inputted by the viewer, the table of the receiving area versus the transmission parameters in all parts of the country stored in advance is searched, and the transmission parameters of the receiving area are searched. By performing tuning and demodulation based on the source, initial tuning can be quickly and reliably performed. Further, by comparing and updating the received transmission data with the stored transmission data, it is possible to store the latest data.

According to the second aspect of the present invention, by detecting NIT data included in the TS stream, if the actual tuning result such as frequency information is different from the actual tuning result,
By storing the difference so that the tuning can be performed correctly, always taking the difference into account, and converting the frequency information, the tuning can be surely succeeded. On the other hand, when the tuning operation is started only with the NIT information without storing the difference, the tuning may not be successfully completed forever.

According to the third aspect of the present invention, the transmission parameters actually tuned are arranged, for example, for each broadcasting company, and when the receiving area is changed due to moving or the like, the initial tuning is stored and organized before. By giving priority to tuning based on the information obtained, tuning can be performed more quickly. This control focuses on the fact that transmission parameters have a correlation in a reception area nationwide for each broadcaster.

The invention according to claim 4 has the following effects. Digital terrestrial broadcasting is initially introduced in a limited area and will be gradually expanded. At this time, transmission parameters may be frequently added / aborted / changed in the reception area. The revision information is not always obtained from the result of the initial tuning. In the invention according to claim 4, a modem provided as an essential function of the digital broadcast receiver is used to access a server containing the revision information in advance. Then, the information is taken into the receiver. By adopting such a configuration, it is possible to always obtain accurate revision information, and the initial tuning becomes faster.

The purpose of the invention according to claim 5 is the same as that of the invention according to claim 4, but in the invention according to claim 5, the download which is a part of the broadcast wave receiving function without using a modem is used. Using the system, it is possible to update revision information at once for all receivers via broadcast waves, and there is an advantage that updating can be performed efficiently and in large quantities.

The invention according to claim 6 has the following effects. One of the great features of terrestrial digital broadcasting is mobile service. In a moving object, it is difficult for a viewer to accurately input or know positional information during movement, and a reception area input and initial tuning are required again every time the reception area changes, and seamless reception cannot be continued. . Therefore, in the invention according to claim 5, an automatic positioning system is used to specify a reception area, and this sequentially detectable position information is converted into a regional code specification of the receiver, and the mobile terminal is moved by combining the above-mentioned tuning operation. It becomes possible to continue receiving seamlessly even in the body.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a standard terrestrial digital broadcast receiver.

FIG. 2 is a block diagram illustrating a main configuration of a terrestrial digital broadcast receiver according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a main configuration of a terrestrial digital broadcast receiver according to a second embodiment of the present invention.

FIG. 4 is a block diagram illustrating a main configuration of a terrestrial digital broadcast receiver according to a third embodiment of the present invention.

FIG. 5 is a block diagram showing a main configuration of a terrestrial digital broadcast receiver according to a fourth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 channel selection unit 2 OFDM demodulation / decoding unit 3 demultiplexing unit 4 information source decoding unit 5 ADC 6 OFDM frame decoding unit 7 TMCC decoding unit 8 reception area search unit 9 demodulation parameter control unit 10 demodulation parameter storage unit 11 OFDM decoding unit 12 multiplexing Separation unit 13 Frequency difference storage and conversion unit 14 Modem 15 Modem control and data conversion unit 16 Automatic positioning system 17 Reception area detection unit

Claims (6)

[Claims] 1. An apparatus comprising: means for inputting a reception area or service area; and means for storing transmission characteristics such as a reception frequency, a modulation method, a mode, and a guard interval, and acquiring the information on the reception area. Initial tuning is started based on the pre-stored reception frequency and transmission specification correspondence table nationwide, and when the tuning is successful, the transmission specifications such as the reception frequency and modulation method, mode, and guard interval are updated. Digital broadcast receiver. 2. A system according to claim 1, further comprising means for separating a network information table (NIT) from the demodulated digital signal (MPEG-TS) and storing a reception frequency and a service list from the information. A digital broadcast receiver comprising means for separately storing a difference between a tuned / synchronized frequency and a frequency described in NIT. 3. The transmission according to claim 1, wherein when moving in a receiving area or a service area, the transmission data at the time of starting the initial tuning / synchronization has already been stored at the time of previous synchronization. A digital broadcast receiver configured to start tuning with priority from specifications. 4. The digital broadcast receiver according to claim 1, wherein a reception frequency and transmission specification correspondence table nationwide are collected via a modem and stored. 5. The digital broadcast receiver according to claim 1, wherein a reception frequency and transmission specification correspondence table nationwide are distributed, collected, and stored by a download system. 6. The digital broadcasting system according to claim 1, wherein, when receiving at a moving body such as an automobile, a reception area at the time of movement is linked with an automatic positioning system for the moving body so as to perform automatic tuning. Receiving machine.