JPH11261501A - Digital broadcasting receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly display plural data services included in a piece of ensemble as service components in a car radio for a DAB(digital audio broadcasting). SOLUTION: This receiver detects all data services included in an ensemble, decides whether or not they are decodable in order of a preliminarily defined priority and shows a data service that is decodable and is the highest order of the priority on an indicator at the time of starting to tune the ensemble. Also, a priority is preliminarily determined about the selection of the data services and a data service selected according to the priority is displayed and outputted. Also, whether or not a data service can be displayed and outputted against hardware restraints is decided in order of an upper priority and a data service which can be displayed and outputted and also has the uppermost priority is displayed and outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to, for example, DAB
(Digital Audio Broadcasti
The present invention relates to a digital broadcast receiver for receiving a digital broadcast such as ng (digital audio broadcast), and more particularly to a digital broadcast receiver including a data service.

[0002]

2. Description of the Related Art DAB has attracted attention as a radio broadcast format capable of coping with deterioration of sound quality due to interference due to multi-localization of FM broadcasting and difficulty in receiving good quality on a mobile body. DA
B has been developed by EUREKA (European Advanced Technology Development Plan), and its specifications have already been defined. As a modulation method, π / 4 shift DQPSK-OFDM is used.
(Differential Quadrature
Phase Shift Keying-Orthog
onal Frequency DivisionMu
ltiplex: orthogonal frequency division multiplexing), which is characterized by being less susceptible to fading and multipath.
Using the PEG layer II, a large number of stereo broadcasts and data broadcasts are enabled with a transmission bandwidth of 1.5 MHz. D
In AB, one ensemble includes a plurality of services, each service includes a plurality of service components, and a data service exists as one of the service components.

[0003]

The conventional digital broadcasting receiver cannot display the data service effectively. That is, in FM broadcasting and the like, one data service is included for one radio broadcast, and it is sufficient to display the tuned FM broadcast data service. In DAB, however, a large number of data services are included in one ensemble. Therefore, it is difficult to adopt a data service display method for FM broadcast radio.

An object of the present invention is to provide a digital broadcasting receiver which overcomes the above-mentioned problems.

[0005]

According to the digital broadcast receiver (10) of the present invention, one ensemble includes a plurality of services, each service includes a plurality of service components, and the data service includes a plurality of service components. One ensemble exists as one of the service components, and is transmitted in an orthogonal frequency division multiplex modulation scheme. Then, when tuning of the ensemble is started, all data services included in the ensemble are detected, and the data service selected based on a predetermined criterion is displayed and output.

[0006] Digital broadcasting is mainly DAB, but is not limited to DAB. Digital broadcasting is not limited to radio broadcasting, but also includes television broadcasting. At the start of tuning of the ensemble, not only when the ensemble is switched automatically or at the instruction of the user, but also when the digital broadcast receiver (10) starts up, that is, the user sets the digital broadcast receiver (10). This includes when the power is turned on. Upon power-on, the digital broadcast receiver (10) starts tuning the ensemble in the same manner as when the ensemble is switched. The digital broadcast receiver (10) includes at least a DAB car radio (10).

The names of ensembles, services, and service components are only used for the sake of convenience. DAB-compliant names are used for convenience, as long as these ensembles, services, and service components have the same relationship. And another name may be used.

The digital broadcast receiver (10) detects all data services included in the ensemble at the start of tuning of the ensemble, and selects one data service from the data services based on a predetermined criterion. Since the data service is displayed and output, the data service can be smoothly displayed and output at the time of startup and at the time of switching.

According to the digital broadcast receiver (10) of the present invention, priorities are determined in advance for data service selection, and the selected data service is displayed and output according to the priorities.

The priority means, for example, that a packet mode data service is prioritized over a stream mode data service (higher priority) as a first stage priority standard. The second tier priority is 3 instead of 16-bit data service
Priority is given to 2-bit data service. Further, those having the same priority in the first and second stages give priority to the primary data service over the secondary data service in the priority standard in the third stage. Data services are usually transmitted in packet mode rather than stream mode and in 32 bits rather than 16 bits, and the data service of the ordinary transmission method is more important than the data service of the less-used transmission method. Presumed to be high,
Also, it is presumed that the primary is more important in data service than the secondary. The priority is based on the type of the data service, for example, a traffic message channel (Traffic Message Channel).
l) or paging.

In this way, the data service having the higher priority is displayed and output preferentially, and a useful data service can be presented to the user.

[0012] According to the digital broadcast receiver (10) of the present invention, it is determined whether or not display output is possible with respect to hardware restrictions from the higher priority order, and the display output is possible and the priority order is higher. Display and output the top data service.

The display output of the data service is restricted by the hardware of the digital broadcast receiver (10). That is,
If the total number of channels for transmitting the data service and the amount of data are large, decoding of the data service by the digital broadcast receiver (10) becomes difficult on hardware. Therefore, if a data service that is difficult to display and output is selected on the hardware, the data service with the next highest priority is examined without leaving the data service as it is, and the data service with the highest priority that can display and output is selected. It will be displayed and output.

According to the digital broadcast receiver (10) of the present invention, when the data service is switched by the user, the data service is selected so that the data service having the higher priority is selected first according to the priority. It can be switched.

When the user switches the data service, the priority of the selection of the data service at the time of starting the tuning of the ensemble is used, so that even when the user manually switches the data service, an efficient data service can be provided. Selection becomes possible.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram of a DAB car radio 10. DAB Car Radio 10
Is equipped with a main body 12, a DAB control microcomputer 26 separate from the main body 12, and the like. In the main body 12, the DAB system microcomputer 14 has a memory 16 and a plurality of ensembles (each ensemble is transmitted by radio broadcast radio waves modulated by DQPSK-OFDM, and one ensemble has a bandwidth of about 15 MHz). And normally includes six broadcast programs.), And designates one ensemble, and sends the frequency data of the designated ensemble to the RF block 18. The RF block 18 stores the ensemble RF (Radi) specified by the DAB system microcomputer 14.
o Frequency) signal is extracted and demodulated by the demodulation block 20
Send to In the demodulation block 20, R from the RF block 18
The F signal is demodulated as DAB data, and the channel decoding block 22 decodes the demodulated signal from the demodulation block 20 for the corresponding channel based on the channel information from the DAB system microcomputer 14. Thus, the data of the required channel in the ensemble designated by the DAB system microcomputer 14 to the RF block 18 is decoded in the channel decoding block 22. Among the digital signals decoded in the channel decoding block 22, the audio data is sent from the channel decoding block 22 to the audio decoding block 24, and the FI data such as a program type other than the audio data is transmitted.
G data (FIG is described later) is sent from the channel decoding block 22 to the DAB system microcomputer 14. The audio decoding block 24 decodes the audio data of the sub-channel designated by the DAB system microcomputer 14 out of the audio data input from the channel decoding block 22, and sends it to left and right speakers (not shown). DA
The B control microcomputer 26 has a memory 28,
Exchanges data with the DAB system microcomputer 14 of FIG. The DAB control microcomputer 26 receives an instruction from the user via the key 30 and outputs data such as a data service to the display 32 to display the information.
It informs the user.

In FIGS. 2 to 6, communication protocols of various elements of DAB such as a transmission frame will be described as appropriate. For details, see the European Telecommunications Standards Association (European Telecommunications).
indications Standards Instiu
te) issued by the European Telecommunications Standard (European Telecommunications)
ionics Standard).

FIG. 2 shows the structure of a DAB transmission frame. Transmission frame (Transmission fra
me) is the synchronization channel, FIC (Fast)
Information Channel) and M
It has SC (Main Service Channel). The FIC further includes a plurality of FIBs (Fast
Information Block), MS
C is a plurality of CIFs (Common Inter
left Frame). The DAB has specifications from mode 1 to mode 3, and the transmission frame time (duration) and the number of FIBs and CIFs in one transmission frame are different for each mode. For example, in mode 1, the time of one transmission frame is 9
The number of FIBs and CIFs in one transmission frame of 6 ms is 12 and 4, respectively.

FIG. 3 is a view showing an example of the DAB service structure. The ensemble (Ensemble) whose ensemble label (ensemble name) is DAB ENSEMBLE ONE has a service label of Alpha 1 Radio (ALPHA1 RADIUS).
O), a plurality of services such as beta radio (BETA RADIO) and alpha 2 radio (ALPHA2 RADIO). The user hears the selected service from the DAB car radio 10.

The alpha 1 radio is a primary (pri
service component (Service comp)
contents, one secondary and one secondary
It has two service components of y). The primary service component is audio, and the secondary service component is a traffic message channel: TMC (Traffic Message Cha).
nel) and service information: SI (Service In)
formation). The audio component and the SI are transmitted on separate sub-channels (SubCh) in the MSC, and the TMC is transmitted in the FIDC (Fast Info) in the FIC.
transmission (Ration Data Channel).

Beta radio has two service components.
Audio and secondary audio (secondary a
audio component), both of which are MS
On the C subchannel.

The alpha 2 radio has the same TMC and SI as the alpha 1 radio, and the audio may be the same as the alpha 1 radio depending on the switch.

FIG. 4 is a structural diagram of the FIB. FIB
A total of 256 bits, the first 30 bytes of FI
B data area (FIB data field) and rear 16-bit CRC (Cyclic Redunda)
ncy Check word). The FIB data area further includes a plurality of FIG (Fas
t Information Group), one end marker (Endmarker), and one padding (filling the remaining bits with 0s to fit the FIB data area to bytes). The part of FIG is a useful data area (useful data view).
ld). Each FIG is, in order from the beginning, a FIG type, a Length (length: represents a bit length of a subsequent FIG data area), and a FIG data area (FIG.
data field). Fig type and Le
ngth forms a FIG header.

FIG. 5 is a structural diagram of the FIG data area of FIG. 4 in which the FIG type is 0 (000 in 3-bit binary notation). The FIG data area further stores C / N
(Current / Next), OE (Other E)
nsemble), P / D (Programme / Da
ta), Extension, Type 0 area (Type
0 field). Extension is 1 to 4
And 7, when C / N = 0, it means the current multiplex structure, and when C / N = 1, it means the next multiplex structure. Also, C / N =
When it is 1, it means that the type 0 area is related to the following arrangement. Extension is 6, 9, 11, 1
In the case of 8, 21, 22, 23, 24, 25, 27, and 30, C / N indicates the version number of the type 0 area.
OE is Extension = 12, 16, 17, 21,
24, 30 are used, and OE = 0 indicates this type 0
The information of the area means that it is related to this ensemble, and OE = 1 means that it is related to another ensemble. P / D = 1 indicates SId of type 0 area
Is the 16-bit Sid used for program services
, And P / D = 0 indicates that S in the type 0 area
Id is the 32-bit Sid used for data service
Means that This P / D is Extension
Are 2, 9, 23 and 24, and when not used, SId is in 16-bit format.

FIG. 6 is a structural diagram of FIG. 0/2. Note that each FIG is represented by the FIG type and the Extension as FIG0 / 2. The type 0 area has a plurality of service (v... K... T) areas. The service ID (SI
d) together with the service component description (Servicec c
omp. (description) is written. Then, in the service component description, TMId = 0
2 (MSC stream data)
data)), DSCTy (Data Serv)
ice Component Type: data service component type) and SubChId (see MSC in FIG. 3). Thereby, when a data service is included, the SubC related to the data service is included.
hId is determined. The data service component type includes a traffic message channel (Traffic M).
Essage Channel), Emergency Warning System
s) and paging.

FIG. 7 is a flowchart of the data service display routine. In S40, it is determined whether or not the tuning of the ensemble has started, and if the determination is YES, S4
Proceed to 1; if NO, end this routine. Ensemble tuning started when the user started the DAB car radio 10
Occurs when the user is powered on, or when the user or the listening ensemble is manually switched to another ensemble. In S41, FIC (Fast Information)
ion channel) is determined,
If the determination is YES, proceed to S42; if NO,
The routine ends. Since the data service is included in the FIC, the display and output of the data service cannot be performed unless the FIC can be captured. In S42, a predetermined time is waited. This is because it takes a predetermined time to grasp the configuration of the data service from the acquired FIC. In S43, it is determined whether or not there is a data service in the ensemble. If the determination is YES, the process proceeds to S48, and if NO, the routine ends.

At S48, all data services included in the ensemble are listed. In S49, the data services are rearranged (sorted) according to a predetermined priority. The priorities are as follows: The packet mode data service is prioritized (higher priority) over the stream mode data service as the first-stage priority criterion, and those having the same first-stage priority are assigned the next second-stage priority criterion. A 32-bit data service is prioritized over a bit data service. Further, those having the same priority in the first and second stages give priority to the primary data service over the secondary data service in the priority standard in the third stage.

At S53, i = 1 is set, and the routine proceeds to S54.
In S54, the data service having the i-th priority is selected. In S55, it is determined whether or not the selected data service can be decrypted. If the determination is YES, the process proceeds to S56, and if NO, the process proceeds to S57. DAB Car Radio 10
If the number of channels of the selected data service or the data capacity of the data service is excessively large due to the hardware restrictions described above, the DAB car radio 10 cannot decode the selected data service. In S56, the selected data service is actually decoded and displayed on the display 32. In S57, it is determined whether or not the decryption check in S55 has been completed for all the data services. If the determination is YES, the routine ends, and if the determination is NO, the process proceeds to S58. In S58, i is incremented by 1 and in S5
Return to 4.

The list of data services sorted by priority created in S49 of the flowchart of FIG. 7 can also be used when a user manually switches data services within the same ensemble. That is, when the user switches the data service currently displayed on the display device 32 by using the up / down switching key, the up operation is performed with one priority which is higher than the data service currently displayed.
The data service is sequentially switched to the data service of the higher rank, and in the down operation, the data service having the priority of the currently displayed data service is one priority
It is possible to sequentially switch to the data service of the lower order. Also, at this time, if it is determined in S55 that the decoding display is difficult, the data service is skipped and the data service can be switched to the next higher or lower data service.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of a DAB car radio.

FIG. 2 is a diagram showing a structure of a DAB transmission frame.

FIG. 3 is an exemplary diagram of a DAB service structure;

FIG. 4 is a structural diagram of an FIB.

FIG. 5 is a structural diagram of a FIG data area of FIG. 4 whose FIG type is 0;

FIG. 6 is a structural diagram of FIG0 / 2.

FIG. 7 is a flowchart of a data service display routine.

[Explanation of symbols]

10 Car radio for DAB (receiver for digital broadcasting) 32 Display

Claims (4)

[Claims] 1. An ensemble includes a plurality of services, each service includes a plurality of service components, a data service exists as one of the service components, and the one ensemble includes orthogonal frequency division multiplexing. A digital broadcast receiver (10) that receives a digital broadcast transmitted by a modulation method detects all data services included in the ensemble at the start of tuning of the ensemble, and selects a data service selected based on a predetermined standard. And a digital broadcast receiver. 2. The digital broadcast receiver according to claim 1, wherein priorities are determined in advance for selecting a data service, and the selected data service is displayed and output according to the priorities. 3. A method according to claim 1, wherein it is determined whether or not display is possible with respect to hardware restrictions from a higher priority, and a data service which is capable of display output and has the highest priority is displayed and output. The digital broadcast receiver according to claim 2. 4. When a user switches a data service, the data service is switched so that a data service having a higher priority is selected first according to the priority. A digital broadcast receiver according to claim 2.