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Publication numberCA2837643 A1
Publication typeApplication
Application numberCA 2837643
Publication date8 Apr 2001
Filing date6 Oct 2000
Priority date8 Oct 1999
Also published asCA2322909A1, CA2322909C, CA2575035A1, CA2575035C, CA2575037A1, CA2575037C, CA2575038A1, CA2575038C, CA2627816A1, CA2627816C, CA2628000A1, CA2628000C, CA2629277A1, CA2629277C, CA2630140A1, CA2630140C, CA2688848A1, CA2688848C, CA2688849A1, CA2688849C, CA2688851A1, CA2688851C, CA2688917A1, CA2688917C, CA2688918A1, CA2688918C, CA2688919A1, CA2688919C, CA2688931A1, CA2688931C, CA2688933A1, CA2688933C, CA2689061A1, CA2689061C, CA2689063A1, CA2689063C, CA2689070A1, CA2689070C, CA2730358A1, CA2730358C, CA2730368A1, CA2730368C, CA2730576A1, CA2730576C, CA2730840A1, CA2730840C, CA2767311A1, CA2767311C, CA2776412A1, CA2776412C, CA2776418A1, CA2776418C, CA2776605A1, CA2776605C, CA2776645A1, CA2776645C, CA2776655A1, CA2776655C, CA2796906A1, CA2796906C, CA2796926A1, CA2796926C, CA2797143A1, CA2797143C, CA2797145A1, CA2797145C, CA2797146A1, CA2797146C, CA2824560A1, CA2824560C, CA2824562A1, CA2824562C, CA2824564A1, CA2824564C, CA2824634A1, CA2824634C, CA2824638A1, CA2824638C, CA2837460A1, CA2837460C, CA2837461A1, CA2837461C, CA2837617A1, CA2837617C, CA2837633A1, CA2837633C, CA2837640A1, CA2837640C, CA2837643C, CA2837675A1, CA2837675C, CA2837908A1, CA2837908C, CA2837910A1, CA2837910C, CN1187981C, CN1305309A, US7051359, US7051361, US7073194, US7080401, US7100189, US7448064, US7448065, US7469415, US7603695, US7620972, US7620973, US7735112, US7748024, US7757266, US7779447, US7779448, US7802289, US7814529, US7814530, US7831994, US7882534, US7882535, US7882536, US7886331, US7958538, US8347330, US8539521, US8539522, US8544041, US8555307, US8640155, US8677405, US8683506, US8701142, US8707344, US8707345, US8707356, US8707367, US8707368, US8726333, US8732752, US8739209, US8752082, US8782695, US8898699, US8910204, US8910205, US8938754, US8966529, US8978063, US8984553, US8997147, US9003444, US9003469, US9015752, US9015753, US9015754, US9021523, US9021524, US9032436, US9038101, US9043836, US9078032, US9084009, US9088806, US9113179, US9124927, US9124938, US9294812, US9300988, US9307271, US9307282, US9351042, US9525915, US9525916, US20040244052, US20040250290, US20040268382, US20040268411, US20040268412, US20050005307, US20050163148, US20080075105, US20080080546, US20080083007, US20090172735, US20090178076, US20090178077, US20090219448, US20090219450, US20090222856, US20090322965, US20100031289, US20100058392, US20100122298, US20100122299, US20100169922, US20100169923, US20100169924, US20110187923, US20120137331, US20120144431, US20120144432, US20130010200, US20130010201, US20130010202, US20130014204, US20130081086, US20130219450, US20130298165, US20130305284, US20130305309, US20130305310, US20130312036, US20130339995, US20130340008, US20130340010, US20130347042, US20140089974, US20140089975, US20140089976, US20140089977, US20140089978, US20140259064, US20140259066, US20140259076, US20140259077, US20140351856, US20140366077, US20140373056, US20140373058, US20140373059, US20140373060, US20140373068, US20140373069, US20140373072, US20140373083, US20140373084, US20150135215, US20150143428, US20150143429, US20150195610, US20150195622, US20150319483, US20150319495, US20150319496, US20150350695, US20150350696, US20150358673, US20150365718, US20170064392
Publication numberCA 2837643, CA 2837643 A1, CA 2837643A1, CA-A1-2837643, CA2837643 A1, CA2837643A1
InventorsJin Pil Kim
ApplicantLg Electronics Inc., Jin Pil Kim
Export CitationBiBTeX, EndNote, RefMan
External Links: CIPO, Espacenet
Virtual channel table for a broadcast protocol and method of broadcasting and receiving broadcast signals using the same
CA 2837643 A1
Abstract
A virtual channel,table for broadcasting protocol and a method for broadcasting by using the virtual channel table includes identification information identifying and permitting discrimination of active and inactive channels contained in the virtual channel table. At a receiver, the virtual channel table transmitted from the transmitting side is parsed, thereby determining whether the current received channel is an active or inactive channel.
Claims(22)
1. A virtual channel table for a broadcast protocol, comprising identification information in a bit stream syntax thereof, said identification information identifying each channel as one of an active and an inactive channel.
2. The virtual channel table of claim 1, wherein said virtual channel table is included in a program and system information protocol for a digital broadcast.
3. The virtual channel table of claim 2, wherein said digital broadcast is any one of a digital terrestrial broadcast and a digital cable broadcast.
4. The virtual channel table of claim 1, wherein said identification information sets a value of a program number. field in the virtual channel table to *0* to indicate that a corresponding channel is an inactive channel.
5. The virtual channel table of claim 1, wherein said identification information sets a value of a number of elements field of a service location descriptor in the virtual channel table to "0" to indicate that a corresponding channel is an inactive channel.
6. The virtual channel table of claim 1, wherein said identification information indicates that a corresponding channel is an inactive channel whenever a service location descriptor is not included in the virtual channel table.
7. The virtual channel table of claim 1, wherein said identification information assigns at least one bit of a reserved field to indicate that a corresponding channel is an inactive channel.
8. The virtual channel table of claim 7, wherein said reserved field is positioned in a statement of a for loop in a bit stream syntax of the virtual channel table.
9. The method of broadcasting using a virtual channel table in a broadcasting protocol, said method comprising:
including identification information in the virtual channel table, said identification information identifying a channel as being one of an active and an inactive channel, and-transmitting the virtual channel table; and determining at a receiver whether the channel is inactive based upon, the identification information defined in the virtual channel table, by parsing the virtual channel table.
10. The method of claim 9, wherein including identification information further comprises, when a channel is inactive, setting a value of a program number field in the virtual channel table to "0" and inhibiting a service location descriptor from being transmitted through the virtual channel table.
11. The method of claim 9, wherein including identification information further comprises setting a value of the program number field and a value of a reserved field assigned for recognizing an inactive channel in the parsed virtual channel table to "0."
12. The method of claim 9, wherein determining at the receiver whether the channel is inactive comprises determining that the channel is inactive when a corresponding service location descriptor is not received in the virtual channel table.
13. The method of claim 9, wherein determining at the receiver whether the channel is inactive comprises determining that the channel is inactive when a value of a reserved field assigned for recognizing an inactive channel in the parsed virtual channel table is "0."
14. The method of claim 9, wherein determining at the receiver whether the Channel is inactive comprises determining that the channel is inactive when a value of a program number field in the virtual channel table iS "0."
15. In a digital television receiver, a method of inhibiting display of an inactive channel, comprising:
receiving a digital broadcast signal comprising a virtual channel table;
parsing the virtual channel table;
retrieving identification information from the parsed virtual channel table indicating whether a channel is inactive; and and, in response to said identification information indicating that the channel is inactive, inhibiting display of said channel when said channel is selected by a user.
16. The method of claim 15, wherein retrieving the identification information comprises reading a value of a reserved field for identifying an inactive channel in the patted virtual channel table.
17. The method of claim 15, wherein retrieving the identification information comprises reading a value of a program number field in the parsed virtual channel table.
18. The method of claim 15, wherein retrieving the identification information comprises determining whether a service location descriptor is found in the parsed virtual channel table.
19. In a digital broadcast transmitter, a method of indicating an inactive channel, comprising:
generating a virtual channel table, including within the virtual channel table information indicating the inactive channel; and transmitting the virtual channel table as part of a digital broadcast signal.
20. The method of claim 19, wherein including within the virtual channel table information indicating the inactive channel comprises setting a value of a program number field in the virtual channel table to indicate the inactive channel.
21. The method of claim 19, wherein including within the virtual channel table information indicating the inactive channel comprises assigning at least one bit of a reserved field to indicate the inactive channel.
22. The method of claim 19, wherein including within the virtual channel table information indicating the inactive channel comprises omitting a service location descriptor.
Description  (OCR text may contain errors)

VIRTUAL CHANNEL TABLE FOR A BROADCAST PROTOCOL
AND METHOD OF BROADCASTING AND RECEIVING BROADCAST SIGNALS
USING THE SAME
This application is a divisional of Canadian Patent Application Serial No. 2,824,634, which is a divisional of Canadian Patent Application Serial No.

2,796,926, which is a divisional of Canadian Patent Application Serial No. 2,767,311, which is a divisional of Canadian Patent Application Serial No. 2,688,918, which is a divisional of Canadian Patent Application Serial No. 2,628,000, which is a divisional of Canadian Patent Application Serial No. 2,575,037, which is a divisional of Canadian Patent Application Serial No. 2,322,909, filed on October 6, 2000.
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to a virtual channel table for a broadcast protocol and a method of broadcasting using the same.
Discussion of the Related Art Generally a program and system information protocol (hereinafter, referred to PSIP) of an advanced television systems committee (hereinafter, referred to as ATSC) standard for digital television broadcasting contains a virtual channel table (VCT).
The PSIP typically contains an electronic program guide (EPG) and system information (SI). The PSIP is defined as the protocol of the ATSC standard for terrestrial and cable digital television broadcasting, which parses encoded messages by using a moving picture experts group-2 (MPEG-2; ISO/IEC 13818-1) system to thereby provide various kinds of information on the broadcast programs. This ATSC standard is described in "Program and System Information Protocol For Terrestrial Broadcast and Cable", ATSC
Document A/65, 23 DEC 1997.

CA 02837643 2013-12-19 , . .
, = .
. . =
.. ._ . __:___.: =
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. . . 74420-21D6 t . ' - = ' =
:-. = ..
_ . .
...
It other words, the HIP tranemits'and receives = . '-' . .
, . : 'audio/videp clata With MOEG-2=video and 4C.-1 audiolormata4 ' = =
and. contains several:tables for=transmitting information on . = - .
. _ .
=
.
the channel of each broadcasting itation,,and information on , '. = 5 the. programs on each channel; The PSIP has .a. primary .
function of conducting the'aUdio and. video services'of the -= .
broadcast correiponding to a desired:channel, and an = =
, .
.
.
. = additional function-of-conducting the elec4ronic program' =
. = service for the broadcast programs.
.=
= .
. . .
=
- . . .
, . . .
' . The channel information for the channel selection - ..
.
.
.. .
-. ..-. and the packet identification (PIM. information for .
.. -reception of the, and.video data are contained .in a .
.
_ . .
...virtual Channel. table omal, and the eleCtronic,progrm ' = , , .
= , . .. Service, infOrmation on the broadcast programs on each.
.
=
15' channel ts contained in: an .event information* table (HIT). . =
.
Also, the PSIP.contains a systemtime.table (STT): foetime =
.
.
.
.
.
Information', a rating region table (M)' fortranemitting ' ..
, .
.=
=
. = ' information on the region, and organization .,for program - .
: -. _. . =
.
.
' _ - = rating, an extended text table.(ETT) for providing. an : . . .
-20 additional .explanation On...0e channel and broadcast, program;
. .,. = , , .
- and a' master guide tableA=MOT) for management of the version =
. . .
. of each table-mentioned'above And the packet identification:
.
. = APID).. these tables al's transmitted in data units, which.
' are called sections,' Namely, all of the tables have one or . .
25. more sections' as a basic, unit., . .
=
= .
. = .
.
. .
. .
- = = By way of exaMple, the Virtual. channel table may .
.
. . = , .
=
be divided* into. 256 sections. A single section may Contain.
' information on several Virtual channels,, but information for =
, .
_ =
.
' a single -virtual channel may.not'be spread over on two' or .
.
. .
.
. = -.
. = .. .
.:' . = . . Fig. 1. is, eldiagram illuitrating.the bit stream . . , _ .
=
-. .-= . syntax of a general virtual channel table for terrestrial , . , = .
- = - ' -2- ' = .
.
.
. .
.
_ = ' . = = = =
=
.- =
.
= .
. .
. . .
. . . .
.
. . . .
.
.
= = ' =
= =
. ,, = , .
.
' ' . ' ' =
= .

=

=
=
broadcast, which has been described in the above-mentioned = docuMent A/65. The general virtual, channel table contains a transport stream identifier, a major channel number, a minor channel number, a=short channel name, a carrier frequency, a program number and the like, and contains additional =information in the descriptor(s) thereof.
Referring to Fig. 1, the virtual channel table has the table identifier field of "Oxaim, and the value of the = packet identification (PID) for the virtual channel table is "OxiFFB". The version number field "version number"
represents the version value of the virtual channel table, the section number field "section number" represents a corresponding section number, the last section number field "last section number" represents a last section ntimber of ¨ =
the virtual channel table, and the section number :channel field "num channels_in section" represents the number of whole virtual channels existing within the Sections of the =
virtual channel table.
=
.The short name field "short name" within the . .
statement in the "for loop" represents the name of the .virtual channel, and the major channel number field "major channel_number" represents a major channel number among the virtual-channels defined in the statement mentioned above. Each virtual channel number is connected to the major and minor channel numbers, respectively, .and =
the major and minor channel numbers function as the user =
= reference number for the corresponding virtual channel. -In other words, the virtual channel table carries the data for , each virtual channel through the statement of the =
"for loop". =
The program number field "program number" contains the information for connecting the virtual channel where the = -3-=

= MPEG-2 program association table .(PAT), and program map table = (PMT) are defined, which corresponds to the program .numbers = in the program association table and the program map table.
In this case, the program association table defines the =
=
components of:the program for every program number, namely, = indicates the packet identification of the .transport packet transmitting the program map table. The program map table = defines the list and the annex information thereof on the packet identification of the =. .
' ' =
=
=
. .
=
= =
=
=
=
=
:
=
-4r = =

CA 02837643 2013-12-19 =

=
= transport packet transmitting the program identification number and the bit stream of the video and audio signals constituting the program.
=
The source identifier field "source_id" represents the program source connected to the. =
= corresponding virtual channel. In this case, the source means a specific source such as image, -'text, data or sound. The source identifier field *source id " has a unique value in the transport =
streamtransmitting the virtual channel table. The descriptor length field "deseriptorsjeng-th"
= indicates the whole length of the descriptors of the corresponding virtuat channel, and the =
. additional descriptor length field "additional descriptorsiength" indicates the whole length = :
of all of the.additional descriptors of the=virtual channel table. =
. .
t.
. 10 . Fig. 5 shoWs an exemplary list of descriptors for PSIP tables according to the ATSC
. . =
=
standard. = =
ơ .
Fig. 2 is a diagram illustrating an example of executing. scheduled broadcasting by = !
using four virtual=channels in a broadcasting station.
By way of example, it is. assumed that the scheduled broadcast as shown in Fig. 2 is executed through the _four virtual channels, 51-1, 51-2,51-3 and-51-8 in an arbitrary broadcast =
_ station and a virtual channel' table composed of a single section is transmitted.
.
.
=
If the current tittle is 20:15, the system time table transmits the current time =
= information. In this case, the channels 51-1 and 51-3 broadcasting at the current time 20:15 are 'defined as the aetive channels. =
=
2O.=
, On the other hand, the channel 51-2 is not broadcasting at the current time and is going to be broadcast the next day, and the channel 51-8 is going to be broadcast next at =
06:00. In this case, the channels 51-2 and 51-8, which are not broadcasting at thecurrent time =
:5_ .
. .
=
=
=

74420-21D6 = =
=
20:15 and are going to be broadcaat.in the future, are -=
=
'defined as the inactive channels. =
=
-=
As a result, each channel may be an active or =
' inactive channel, based.upon an arbitrary point in time., =
:5 Within the PSIP, the virtual channel table should contain the active channels as required and may also contain.
=
the inactive -channels as recommended facts, for conducting=
=
.the electronic program guide:
.Therefore, at the current time 20:15 the virtual -channel table may contain information on all of the channels .
= 51-1, 51-2, 51-3 and 51-8, and thus a digital television .-broadcast receiver or a digital cable broadcast receiver =
=
receives the virtual channel table to thereby, provide the = = =
= channel Selection information to TV viewers.
Howevei, as shown in Fig. 1, according to the bit . .
streaM syntax of the virtual Channel table according to the=
. =
. A/65 standard, the digital television broadcast receiver or ' =
the'digital-cable=broadcast-receiver cannot discriminate between the active channels (for example, the channels 51-1 -= 20¨and 51-3) and the inactive channels (for example, the channels =
51-2 and.51-8), .when parsing thevirtual channel table.
.. =
As a-consequence, the TV viewers see a black ' screen because of the 'information on, the inactive channels transmitted'from the broadcast station for providing the electronic program guide. The black screen means the black = .
= background. color is displayed on the screen when an. inactive.
=
channel not broadcasting at a current time is selected. On .
= = the other hand, the character message "service not provided" =
. is displayed on the screen of the black background color by 30 the onscreen display function of the digital television =
. =
bFoaddast receiver' or the digital cable broadcast-receiver.
By way of example, if the TV viewer selects the channel 51-2 = =
= 6 =
.=
= =
=
' =

=

with a channel up .key while viewing the channel 51-1, the audib and video data are not= -displayed because the channel 51-2 is an inactive channel, such that the black background .
color is displayed.on'the screen.
The above-mentioned problem may give many =
= inconvenience to the TV viewers at a point of time when digital television broadcast receivers or digital cable.
broadcast receivers become popular and a.large number of virtual channels are broadcast.
SUMMARY OF THE: INVENTION
= , Accordingly, some embodiments of the present invention are directed to a virtual channel table that.
substantially obviates one or more of the problems due to.
limitations and disadvantages of the related art.
=
An object of-some embodiments of the present =
. invention is to provide a virtual channel table tor a = broadcast protocol, and a method of broadcasting by using the same table, which are capable of identifying and .
pemitting dibcrimination between active and inactive . 20 channels from the channels received by a broadcast receiver.
Another object of some embodiments of the .
=
invention is to provide a virtual channel table for a broadcast prdtocol,'and a method of broadcasting by using =
the same table, which are capable of rapidly displaying only = 25 0 the channels being broadcast at a current time. ;
Additional features and advantages of embodiments of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The 30 objectives and other advantages of the invention will'he = 7 =

> , = = _ 74420-21D6 =
realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
The identification information may be loaded on or included in at least one reserved field in the virtual channel table. Preferably, the identification information assigns at least one or more bits of a reserved field as a =
=

=

=
= .

= = =
. = .
.
.
, _ flag, thereby indicating that a' corresponding channel is an inactive, channel. =
=
For example, the value of the program number field "program number" in the virtual channel table is set to "0", =
.thereby 'indicating that the corresponding channel is the inactive channel.. = =
The identification information sets the value of =
. the number elements field "number elements" (which indicates the number of PID's used for a program) of the service . .
.1 ao' position.. descriptor field "service_location-desoriptor"
(which is usedto list available bie streams by their PID's) - in the virtual channel table to "0", thereby indicating that' the corresponding channel is an inactive channel. =
=
= . ' In.a.case where the corresponding .channel is an inactive. channel,, the virtual channel.table does not contain the .service location descriptor field therein, for the - ==purpose of indicating that the corresponding channel is an = .
inactive'. channel. =
k =
It is to be understood that both the foregoing -general desoriPtion-and thefollowing detailed description =
are exemplary and' explanatory and are intended to provide .
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS.
= -The' accompanyingdrawings,.which are included to .
25. provide .a further understanding of the invention and are incorporated in and constitute- a part of this specification, illustrate embodiments of the :invention and together with the =
description serve to explain, the principles of embodiments of the invention.
= =
. -= =
= =
= =

. r =
= 74420-21D6 In the drawings:
-FIG. '1 is a diagram illubtrating the bit stream syntax of a general virtual channel table for terrestrial broadcast;
.
FIG. 2 is a.-diagram illustrating an example of executing schedule broadc4sting by using four virtual channels in.a broadcast Station;
=
FIG. 1 is a diagram illustrating the bit stream ' = syntax of a virtual channel table for terrestrial broadcast =
according to an embodiment of the present invention;
==
FIG. -4 is a diagram -illustrating the bit stream e : syntax of a virtual channel table for cable according=to another embodiment of the present invention; and FIG. 5 is chart listing various descriptors available according to a program and system information ' protocol of an advanced television systems committee .
standard digital television. broadcast..
=
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS =
Reference will now be made in detail to the =
preferred embodiments of the present invention, examples of .
=
which are illustrated in the accompanying drawings.
According to the present invention, a virtual =
' channel 'table' for a broadcast protocol comprises identification information dapable of identifying and =
permitting discrimination between active and inactive channels in the bit stream syntax thereof. A-transmitting side, namely, a broadcast station transmits the virtual channel table having the identification information to the receivers. Each of the receivers parses the virtual channel = 10 74420-21D6 = =
= = =
.
.
table received, thereby determining whether the channel =
currently selected is an active channel or an inactive.
channel..
=
=
The identification information, which is. capable - 5 . of identifying and permitting discrimination between an' active channel and an inactive channel under the standard of the .PSIP, is contained in at least one field of the virtual .
=
channel table: of the above protocol, such that only active' . = _ = channels. being currently broadcast are displayed to TV.
. 10 .viewers. = =
=
=
Hereinafter, preferred -embodiments of a virtual =
channel table and a method according to the present = =
=
Invention .will be in_ detail described With reference to Figs. 3 and 4.
=
15 In-order for a-digital television receiver and a digital-cable broadcast receiver to parse the virtual .
.
=
Channel tablevarid.thus to determine whether the channel selected currently is an activechannel or an inactive = =
channel, the bit etreamsyntax.of the virtual channel table =
20 may be corrected.
=For example, = the fact that channels 51-2 and 51-8 .
=
are not broadcast at the current time 20:15, but are going to be. broadcast in the future, should be recognized in a =
digital television receiver and a cable broadcast receiver. -=
. 25 In a preferred embodiment, the identification information =
caPable of identifying an inactive channel is contained in -'the program number field "program number", the service =
=
location descriptor field "service_location descriptor"
=and/or Other reserved fields contained in the bit stream 30 syntax.of-the virtual channel table.
=
=

=
=

-= 74420-21D6 Fig. a is a diagram illustrating the bit stream .
syntax of a virtual Channel table for terrestrial broadcast according to an embodiment of the present invention. To indicate that a corresponding channel is an inactive channel, the value of the program number field "program_number" is set to "0". And, since there are no audio and video signals.of the current service location _ descriptor, the value of the number elements field "numbpt_elements" of the service location descriptor "service_location_descriptor".is set to "0". Also, or alternatively, to indicate that the corresponding channel is =
an inactive channel, the service location descriptor "service location descriptor" (Bee Fig. 5) is not contained = in the virtual channel table. In other words, for the digital television receiver and the cable broadcast receiver, the seLyice location descriptor field should be contained in the virtual channel table only in a case where =
the corresponding channel is the active channel. If the corresponding channel is an inactive channel, however, the.
service location descriptor field is not contained in the =
virtual channel table.
In a preferred embodiment, in.order to recognize the fact that the corresponding channel is an inactive channel in a more apparent manner, 1. bit of the reserved =
field of 6 bits for each channel is assigned to define a =
flag indicative of an inactive channel. In the preferred .
embodiment, 1 bit in the reserved 'field between the hidden field "hidden" and the service type field "service type" in .
the statement of the "for loop" is assigned to define a flag =
=

=
indicative of an inactive channel. For example, in a case.
where the flag indicative of the illactive channel is "1", .the corresponding. channel is an active channel, and if the flag is "0", the corresponding channel is an inactive = =
channel.
In the preferred embodiment, the above three cases may be added as requirements to the A/65 standard. Any of all of the three cases may be added to the A/65 standard.
As mentioned above, since the information on an inactive channel. is contained in the. virtual channel table, = the digital television receiver can determine whether the virtual Channel currently received is an active channel or an inactive channel by parsing only the virtual channel table. For example, if the value of the program number . 15 field "program_number" in the virtual channel table is "0";
.if the value of the information on the inactive channel defined by assigning a predetermined bit in the reserved =. field is "0",. or if the service location descriptor field =
"service location descriptor" is not contained in the =
.virtual channel table, the major channel number field "major channel number" and the minor channel number field "minor channel number" defined in the bit stream syntax of the virtual channel table currently transmitted can be used =
to determine that the current virtual channel is an inactive channel for example by both being assigned a value of "0".
On the-other hand, if an. inactive channel has been determined under the above process, the digital television receiver can skip the inactive channel, without displaying it-on =
12a =
=
=

=

=
=
=
= the screen, upon channel conversion by means of a.channel up key or a channel doWn key.
. = . .
4 is a diagram illustrating the bit Stream syntax of a virtual channel table for cable =
=
. .
adcording to another embodiment. As shown, the .virtual cllannel table may be.applied to == cable broadcasting in the same manner.as abov.e. = =
= = .
As is apparent from the foregoing description, a virtual channel table for a broadcast . protocol, and a method of broadcasting by using the virtual channel table are capable of= =
including the identificatien information capable of identifying and permitting discrimination .=
between active- and inactive channels in a transmitting side, and ha receiving side parsing the virtdal channel table to thereby determine whether the channel currently-selected is the aciive- - =
channel or the inactive channel. Therefore, inactive channels may be-skipped, without being = . =
= displayed, upon the channel conversion by using a channel up key or a channel down key, = such that the TV viewer can enjoy channel .surfing in a convenient manner, without viewing a = black screen. Iti addition, the virtual channel table my be transmitted, while containingthe =
inactive channels therein, thereby making it possible to provide a more abundant electronic = 15 = program. service.
== It will be apparent to those skilled in the art that various modifications and vaiiations can be made to the embodiments described herein. =
= =
Thus, it is intended that thepresent invention cnver.the Modifications and =
=vaiiations of this inventionprovided they-come within the scope ofthe Appended claims and =
= their equivalents.
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= , - 1'3 - =
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Legal Events
DateCodeEventDescription
29 Jan 2014EEERExamination request
Effective date: 20131219